CN101557929B - Stretchable sheet and process for producing the stretchable sheet - Google Patents

Abstract

This invention provides a stretchable sheet (10) comprising a number of elastic filaments (13) arranged so as to extend in one direction without mutual crossing, the elastic filaments (13) having beenbonded to stetchable nonwoven fabrics (11, 12) in a substantially nonstreched state over the whole length. The stretchable sheet (10) is produced by taking off a number of elastic filaments (13) in a molten state spun from a spinning nozzle (16) at a predetermined rate, fusing the elastic filaments (13) while stretching, before the solidification of the elastic filaments (13) while stretching, to the nonwoven fabrics (11, 12) so as to allow the elastic filaments (13) to arrange in one direction without mutual crossing, and then stretching a composite (19) comprising the fused elastic filament s (13) in a direction along which the elastic filaments (13) are extended, thereby imparting stretchability to the composite (19).

Description

Stretchable sheet and its manufacturing method

technical field

The present invention relates to a stretch sheet made by compounding elastic filaments and non-woven fabric and its manufacturing method. the

Background technique

As prior art related to a stretch sheet in which elastic fibers are combined with a nonwoven fabric, techniques described in Patent Documents 1 and 2 are known, for example. As shown in Fig. 1 of these documents, the stretch sheet described in these documents is composed of a first nonwoven fabric layer 122, a second nonwoven fabric layer 126, and an elastic body layer 124 positioned between the two nonwoven fabric layers. The elastomer layer 124 is made of scrim, perforated film, elastomer woven fabric, or nonwoven fabric. In Fig. 1 of these documents, it is described that the elastic body layer 124 is composed of an elastic body scrim 130, and the elastic body scrim 130 is composed of a large number of first strands 125 and a large number of second strands 127 perpendicular to each other. . Since the elastic body layer 124 forms such a structure, when the elastic sheet described in Patent Documents 1 and 2 is stretched in a certain direction, the width of the sheet in the direction perpendicular to the stretching direction becomes narrow. That is, the phenomenon of width reduction occurs. Therefore, when the stretchable sheet is used as an outer wrapping material for a pants-type diaper, the material is stretched in the waist direction, and the width decreases in the longitudinal direction of the diaper, so that the diaper becomes easy to fall off, or the diaper falls off easily. Creases appear. In addition, it causes uneven elongation in the width direction in consideration of the configuration of the diaper and the user's motion, so width reduction becomes more conspicuous. In addition, the strands 125, 127 and the non-woven fabric layers 122, 126 are bonded together by heat and pressure, so the strands 125, 127 are trapped in the non-woven fabric layers 122, 126, thereby damaging the non-woven fabric layers. 122, 126 bulkiness. The strands 125, 127 and the nonwoven fabric layers 122, 126 are bonded together by heat and pressure applied from the nonwoven fabric 122 or 126 side, so the temperature on the outer nonwoven fabric side tends to rise during bonding. , tends to be in a state where the temperature on the strand side is lower than the temperature of the nonwoven fabric. Therefore, if it is desired to obtain sufficient bonding strength, there is a problem that the nonwoven fabric melts before the strands due to heat and pressure and becomes thinner. In addition, since it is necessary to melt the resin of the inner fibers in contact with the strands, a higher temperature or pressure is applied, resulting in a problem that the texture is deteriorated. If a non-woven fabric with a high melting point is used, the non-woven fabric fiber itself will not melt, but it will become difficult to melt and bond with the elastic scrim, so the peel strength when it is made into a sheet will decrease. In addition, it is difficult to obtain a soft sheet with a good touch from a nonwoven fabric with a high melting point. the

The technique described in patent document 3 is also known as another technique of a stretch sheet. As shown in Fig. 1, Fig. 2 and Fig. 7 of this document, the elastic sheet described in this document forms a large number of arched parts 13 on the sheet 12 by means of corrugated members 20, 21 having a gear shape. Elastic strands 16 are fusion bonded to the top (bottom) of the arcuate portion 13 . The elastic strands 16 are extruded in a molten state from the die 22 and are fusion bonded to the sheet 12 in an unstretched state. Therefore, the elastic strands 16 and the sheet 12 are joined in point contact, and thus, it is not easy to increase the joining strength. In addition, the arched portion 13 of the elastic sheet material described in this document can no longer be stretched after being flattened, and has a so-called limit of elongation. Furthermore, the use amount of the sheet 12 at the portion where the arched portion 13 is formed and the sheet 12 is loosened increases, which is not economical, and the air permeability also decreases. In addition, this document describes that the sheet 12 before being joined to the elastic strand 16 may be joined to the elastic strand in a state already stretchable in its original roll state. However, it is difficult to convey a nonwoven fabric stretchable in the moving direction without stretching it. Moreover, when the stretch sheet described in Patent Document 3 is wound into a roll, stress relaxation occurs, that is, the shrinkage force gradually decreases when stored for a long time in a state stretched by tension during winding, and the This has a problem in terms of preservation. When the post-processing of the sheet is carried out at a different location, the stretchable sheet must be wound into a roll in consideration of handleability and transportability. the

The elastic sheet-like composite material described in Patent Document 3 is formed by arranging elastic strands on one surface of a sheet made of nonwoven fabric or the like so as to extend in one direction without intersecting each other. The thread is made of a molten thermoplastic material that is elastic when cooled (e.g. elastomeric polyester, polyurethane, polystyrene-polyisoprene-polystyrene, polystyrene-polybutadiene-polystyrene or polystyrene- Poly(ethylene-butylene)-polystyrene). Such a stretchable sheet in which a large number of filaments are arranged extending in one direction without intersecting each other is produced by extruding a molten state from a large number of spinning nozzles arranged at predetermined intervals perpendicular to the conveying direction of the sheet. The filaments are melt bonded to the sheet. the

However, in the above-mentioned method for producing a stretchable sheet, filaments extruded in a molten state from a spinning nozzle may be bent by wind or static electricity before being fused with the sheet. As a result, there is a problem that filaments that should extend straight in one direction on the final product are joined to the sheet in a zigzag state, and a stretchable sheet in which a large number of filaments are arranged at equal intervals cannot be produced. The meandering of the filament can be prevented by pulling the filament extruded from the spinning nozzle at a tension greater than or equal to a specified value. If a tension effective for preventing meandering is applied to the molten filament, sometimes the The filaments are broken (broken), and spinning of the filaments cannot be performed. In particular, when the diameter of the filament is small, the filament breakage often occurs due to pulling, and the productivity of the stretchable sheet decreases seriously. On the other hand, from the viewpoint of improving the texture of the stretch sheet, the diameter of the filament tends to be thinner than that of the elastic yarn used in commercially available absorbent articles such as diapers. the

Patent Document 4 describes a method of forming an elastic strand, elongating the elastic strand in a cooled and solidified state, and bonding the elastic strand to a nonwoven fabric to obtain a stretch sheet. By recovering the elongated portions of the elastic strands, the nonwoven relaxes, thereby exhibiting stretchability throughout its length. Since the elastic strand is cooled and solidified before bonding to the nonwoven fabric, it is necessary to bond the elastic strand to the nonwoven fabric with an adhesive or the like. Therefore, in order to obtain sufficient adhesive strength, a relatively large amount of adhesive is required. If a large amount of adhesive is applied, the gaps between the fibers of the nonwoven fabric will be filled, so the air permeability will decrease. In addition, since a plurality of fibers are bundled together with an adhesive, rigidity is improved. Therefore, it is difficult to obtain a soft and air-permeable sheet. In addition, the elastic sheet described in this document has the same structure as a normal linear rubber elastic body bonded in a stretched state of the elastic thread, so gathers are formed on the elastic sheet, which has poor skin feel and no Cloth-like appearance. In the state where the pleats are formed, the non-woven fabric is stretched to its original state, while the elastic body is stretched, and stress relaxation occurs, that is, the shrinkage force gradually decreases due to long-term storage in the stretched state. , so the stretching force decreases during long-term storage. In addition, in the process of compositing with non-woven fabrics, etc., when the elastic strand is stretched using a roll or wrapped on a roll for conveyance, the elastic strand may stick to the roll or break. silk and other issues. the

In addition, since the strands of the elastomer are relatively thick, it has a hard touch, which is not good in hand. the

Different from the above techniques, an elastically stretchable composite sheet has also been proposed: an elastic sheet made of an elastically stretchable film or elastically stretchable continuous fibers, and an aggregate of non-elastically extensible fibers laminated (see Patent Document 5). The elastic sheet and the fiber aggregate are joined together by discontinuously arranged joints. The constituent fibers of the fiber aggregate are continuous long fibers between joints. The long fibers are neither welded nor melt-bonded between joints, but the fibers are separated and independent from each other. In addition, the long fibers have an irregular curved shape between joints. the

According to Patent Document 5, in the elastically stretchable composite sheet, the long fibers of the fiber aggregates form irregular curves between joints, so that when the sheet is stretched, the elongation will not be affected by the stretch. Fibrous aggregates hinder. However, since the long fibers of the fiber aggregate are separated and independent from each other at the joints, this elastically stretchable composite sheet has low strength against pulling. Furthermore, the peel strength between the fiber assembly and the elastic sheet was also low. In addition, the floating of the long fibers tends to occur between the joints, and the sheet has a fluffy appearance, which is not a good impression of the appearance. the

Patent Document 1: WO00/20206A1

Patent Document 2: WO00/20207A1

Patent Document 3: WO95/34264A1

Patent Document 4: WO01/87214A1

Patent Document 5: US6730390B1

Contents of the invention

The present invention provides a stretchable sheet in which a large number of elastic filaments arranged in such a manner as to extend in one direction without intersecting each other are bonded to an extensible nonwoven fabric in a substantially unstretched state over the entire length thereof . the

In addition, the present invention provides a method for producing a stretchable sheet, wherein a large number of elastic filaments in a molten state spun from a spinning nozzle are drawn and stretched at a predetermined speed, and the elastic filaments are solidified Before, the elastic filaments are melt-bonded with the non-woven fabric in such a way that the elastic filaments are arranged in one direction without intersecting each other, and then the composite body melt-bonded with the elastic filaments is bonded along the elastic filaments. Stretching in the direction of extension, so that the composite has stretchability. the

In addition, the present invention is a method for producing a stretch sheet, which comprises drawing and stretching a large number of elastic filaments in a molten state spun from a spinning nozzle at a predetermined speed, and solidifying the elastic filaments. Before, the elastic filaments are melt-bonded with the non-woven fabric in such a way that the elastic filaments are arranged in one direction without intersecting each other, and then the composite with the elastic filaments is melt-bonded along the direction of the elastic filaments. The stretching direction is stretched so that the composite has stretchability, wherein, before the elastic filaments spun from the spinning nozzle contact the nonwoven fabric, the elastic filaments are spun from the spinning The moving distance from the tip of the nozzle is 600 mm or less. the

Description of drawings

Fig. 1 is a partially cutaway perspective view showing one embodiment of the stretch sheet of the present invention. the

Fig. 2 (a) and (b) are longitudinal cross-sectional views of the elastic filaments in the stretch sheet shown in Fig. 1 in a natural state and in an elongated state, respectively, along the extension direction. the

Fig. 3 is a SEM image of an example of an inelastic fiber showing a state in which the diameter (cross-sectional area) of the fiber changes approximately in a stepwise manner. the

FIG. 4 is an explanatory diagram of a method of measuring melt tension. the

Fig. 5 is a schematic view showing an apparatus preferably used for producing the stretch sheet shown in Fig. 1 . the

Fig. 6 is a side view schematically showing the main part of the device shown in Fig. 5 . the

Fig. 7 is a schematic view showing a state in which the composite is stretched by the apparatus shown in Fig. 5 . the

Fig. 8 is a schematic diagram showing a state in which an inelastic fiber is stretched. the

Fig. 9 is an explanatory diagram of a method of evaluating the misplaced drop property of a diaper. the

Detailed ways

Hereinafter, the present invention will be described based on preferred embodiments of the present invention with reference to the drawings. FIG. 1 shows a partially cutaway perspective view of one embodiment of the stretch sheet of the present invention. the

The stretch sheet 10 of the present embodiment is composed of a total of two nonwoven fabrics, a first nonwoven fabric 11 and a second nonwoven fabric 12, and a large number of elastic filaments 13 sandwiched between the two nonwoven fabrics. Specifically, the stretchable sheet 10 is constituted as follows: a large number of elastic filaments 13 arranged so as to extend in one direction without intersecting each other are in a substantially unstretched state and an extensible stretchable sheet composed of non-elastic fibers. The nonwoven fabrics 11, 12 are bonded. the

The stretch sheet 10 contains elastic resin. The elastic resin imparts stretchability to the stretch sheet 10 and is an essential component of the stretch sheet of the present invention. In the elastic filaments and the stretchable nonwoven fabric which are constituent members of the stretch sheet of the present invention, it is preferable that at least the elastic filaments contain an elastic resin. The stretchable nonwoven fabric may or may not contain elastic resin. As the elastic resin, for example, a thermoplastic elastomer (SBS, SIS, etc.) or rubber, which will be described later, can be used. the

The content of the elastic resin in the elastic filaments is preferably 40% by weight or more, more preferably 70 to 100% by weight. Thereby, the modification of the elastic resin (improvement of formability, oxidation resistance, coloring, etc.) or the bonding strength between the elastic filament and the nonwoven fabric can be improved. The content of the elastic resin in the stretchable nonwoven fabric is preferably 0 to 30% by weight, more preferably 0 to 10% by weight. By containing the elastic resin in the nonwoven fabric, not only the recovery strength can be improved, but also the bonding strength can be improved by the compatibility between the elastic resin contained in the nonwoven fabric and the elastic filament resin. In addition, the unit of the elastic resin contained in the stretchable sheet of the present invention is from the viewpoints of stiffness, skin feel, residual yarn when pulled, recovery strength, and bonding strength between the elastic filament and the nonwoven fabric. The area weight is preferably 1 to 25 g/m ² , more preferably 4 to 15 g/m ² . This weight per unit area is obtained by the method mentioned later.

The bonding strength between the elastic filaments 13 and the nonwoven fabric 11 is preferably 10 cN/25 mm or more, more preferably 20 to 200 cN/25 mm. The bonding strength between the elastic filaments 13 and the nonwoven fabric 12 is also within the above range. By making the bonding strength between the elastic filaments 13 and each non-woven fabric 11, 12 more than 10 cN/25mm, the overall sense of unity of the stretch sheet 10 is improved, and the stretch sheet 10 is stretched or joined with other sheets. , it is possible to effectively prevent the elastic filaments 13 from peeling off from the nonwoven fabrics 11, 12 and the like. On the other hand, if the bonding strength between the elastic filaments 13 and the nonwoven fabrics 11 and 12 exceeds 200 cN/25 mm, the stretching properties of the stretch sheet 10 may decrease, so it is preferable to set the upper limit of the bonding strength as 200cN/25mm. The above joint strength was measured as follows. the

<Measurement method of joint strength between elastic filament and nonwoven fabric>

(1) When there are 2 non-woven fabrics

The stretchable sheet was cut into a test piece having a size of 150 mm in the stretching direction and 25 mm in the direction perpendicular to the stretching direction. This test piece was peeled off about 3 cm in the expansion-contraction direction on one nonwoven fabric and the other nonwoven fabric. At this point, the elastic filaments are peeled off together with the more firmly bonded nonwoven. A part of the test piece peeled off in this way was installed and fixed between the chucks of a tensile testing machine (Autograph AG-1kNIS manufactured by Shimadzu Corporation) in such a way that the expansion and contraction direction was the tensile direction (the distance between the chucks was 25 mm). The test piece was pulled at a pulling speed of 300 mm/min until the chuck distance reached 160 mm to peel one nonwoven fabric from the other nonwoven fabric, and the peel strength at this time was measured. The measurement interval of the peel strength is calculated as follows: set the distance between chucks at 35 to 150 mm, and when the peel strength fluctuates in the manner of showing a maximum and minimum point in the measurement interval, the maximum point (bump point ) The average of the larger 5 points was taken as the average peel strength. When no maximum and minimum points were displayed, the average peel strength was calculated. In addition, as a preferred measurement method of the present invention, Autograph AG-1KNIS manufactured by Shimadzu Corporation is used as a tensile testing machine, and the material testing machine software TRAPEZIUM2 manufactured by Shimadzu Corporation is used for measurement. The point average was used to calculate the average peel strength. According to this method, the average peel strength can be calculated irrespective of whether the maximum and minimum are exhibited or not. The measurement was performed 5 times, and the average value was used as the joint strength between the elastic filament and the nonwoven fabric. the

(2) When the non-woven fabric is 1 sheet

When installing and fixing the test piece between the chucks of the tensile testing machine, install and fix the elastic filament on one chuck, and install and fix the non-woven fabric on the other chuck, in the same way as above (1). proceed. the

For the stretch sheet 10 of this embodiment, except that the joint strength between the elastic filament 13 and each nonwoven fabric 11, 12 is within the above-mentioned range, the stretch sheet 10 is further stretched in one direction (the direction of the elastic filament 13). The strength of the stretch sheet 10 (hereinafter referred to as "25% recovery strength") when it is stretched by 50% to the opposite direction of the stretch direction is preferably relative to the strength of the stretch sheet 10 contained in the stretch sheet 10. The elastic resin has a weight per unit area of 1.0 cN/{50 mm·(g/m ² )} or more, more preferably 2.0 to 10 cN/{50 mm·(g/m ² )}. By making the 25% recovery strength of the stretch sheet 10, relative to the weight per unit area of the elastic resin in the stretch sheet 10, within the above range, especially when used in an outer wrapping material of a disposable diaper, etc., The stretchable sheet 10 can be easily stretched with a small external force when the diaper is worn. Therefore, the diaper is easy to put on, and the fit of the diaper becomes good because it exhibits moderate recovery strength in a state of being worn. The 25% recovery strength per unit area weight of the elastic resin contained in the stretch sheet was measured as follows.

<Measuring method of 25% recovery strength per unit area weight of elastic resin contained in stretch sheet>

The 25% recovery strength of the elastic sheet is obtained by the method described later, and then divided by the weight per unit area of the elastic resin in the elastic sheet obtained separately, thereby obtaining the weight per unit area of the elastic resin in the elastic sheet. 25% recovery strength by area weight. The weight per unit area of the elastic resin in the stretch sheet is obtained by dividing the amount of the elastic resin added in the production of the stretch sheet by the area of the stretch sheet. When the elastic resin can be extracted from the stretch sheet by using a solvent or the like, the weight per unit area of the elastic resin in the stretch sheet can be obtained by the following method. That is, the elastic resin is extracted from the stretchable sheet with a solvent or the like, and the component ratio of the extracted component is determined by analysis such as NMR. The weight per unit area of the elastic resin was obtained by dividing the content of the elastic resin calculated from the extraction ratio by the area of the stretch sheet. According to this method, the elastic resin contained in the elastic filaments constituting the stretch sheet can be extracted, and when the elastic resin is contained in the extensible non-woven fabric constituting the stretch sheet, the elastic resin contained in the non-woven fabric can also be extracted. The elastic resin, so that the weight per unit area of the elastic resin contained in the stretch sheet can be accurately measured. the

The joint strength between the elastic filament 13 and the non-woven fabrics 11, 12 is 10 cN/25mm or more, and the 25% recovery strength per unit area weight of the elastic resin in the stretch sheet 10 is 1.0cN/{50mm·(g /m ² )} or more can be produced by the production method described later. It is particularly important to obtain a stretch sheet having an excellent balance between the above-mentioned interlayer bonding strength and stretch characteristics, in its production process, "before the elastic filaments in a molten state are solidified, the elastic filaments are combined with the Fabric Fusion Bonding". That is, the joining of the elastic filaments 13 and the nonwoven fabrics 11 and 12 by fusion bonding largely contributes to the expression of the aforementioned joint strength and 25% recovery strength. Elastic filaments and non-woven fabrics joined by means other than fusion bonding of the elastic filaments, for example, by overlapping the solidified elastic filaments and non-woven fabrics In the stretch sheet obtained by heat-pressing and integrating them, the fibers constituting the nonwoven fabric are not sufficiently trapped in the elastic filaments, so it is difficult to achieve both the above-mentioned bonding strength and 25% recovery strength.

In order to make the bonding strength between the elastic filament 13 and the nonwoven fabrics 11 and 12, and the 25% recovery strength per unit area weight of the elastic resin in the stretch sheet 10 respectively fall within the above-mentioned specific ranges, as a specific method , For example, the following methods can be mentioned: in the production method described later, 1) adjust the clamping strength when joining elastic filaments and nonwoven fabrics; 2) use when joining elastic filaments and nonwoven fabrics 3) From the top end of the spinning nozzle to the kneading part between the elastic filament and the nonwoven fabric when the elastic filament in the molten state is spun from the spinning nozzle Adjust the distance, etc. By carrying out any of the above 1) to 3), the elastic filaments can be bonded to the nonwoven fabric while maintaining the shape of the elastic filaments to some extent. In general, when a thinner filament is joined to a nonwoven fabric as in the present invention, compared with the case of joining a film that is much wider than the filament to a nonwoven fabric, since the filament is thinner, Therefore, it is particularly vulnerable to damage when joining. The damage refers to a reduction in the cross-sectional area of the elastic filaments in the stretching direction of the stretchable sheet. Due to such damage to the elastic filaments, the recovery strength of the stretch sheet decreases. However, according to the methods 1) to 3) above, the above-mentioned disadvantages do not occur, and the above-mentioned joint strength and 25% recovery strength can be kept within the above-mentioned specific ranges, respectively. the

In the elastic sheet 10 of the present embodiment, the joint strength between the elastic filaments 13 and the nonwoven fabrics 11 and 12 is within the above range, and the 25% recovery strength per unit area weight of the elastic resin in the elastic sheet 10 is Outside the above range, it is more preferable that the average bonding ratio between the elastic filaments and the fibers (nonwoven fabric constituting fibers) constituting the extensible nonwoven fabrics 11 and 12 is 10 to 60%, more preferably 20 to 60%. 50%. A stretch sheet having the average bonding ratio within the above range has sufficient peel strength, and has excellent hand feeling without conspicuous stiffness due to the bonding between the elastic filaments and the fibers constituting the nonwoven fabric. In addition, by setting the average bonding ratio within the above range, the stretch properties of the stretch sheet 10 can be brought close to the stretch properties of the elastic filaments 13 themselves. The weight per unit area of the elastic resin in the usual stretch sheet that contains the elastic resin film is 30～80g/ ^m (g/m ² )}), in contrast, the elastic sheet of the present invention can obtain higher 25% recovery strength and joint strength with less elastic resin per unit area weight.

In order to make the average joining ratio between the elastic filament and the above-mentioned nonwoven fabric constituent fibers within the above-mentioned special range, as a specific method, in addition to the above-mentioned methods 1) to 3), the following methods can also be enumerated: 4 ) Make the melting temperature (forming temperature) of the elastic resin 125°C to 180°C higher than the melting point of the low-melting component with the lowest melting point in the fibers constituting the non-woven fabric; The density is relatively low, ranging from 0.05 to 0.12g/ ^cm3 . By reducing the fiber density of the fibers constituting the nonwoven fabric as in 5) above, a sheet with high recovery strength can be obtained without hindering the fusion bonding and stretching of the elastic filaments to the surface fibers of the nonwoven fabric. The average bonding ratio between the elastic filaments and the fibers constituting the nonwoven fabric was determined as follows.

<Measurement method of the average bonding ratio between elastic filaments and fibers constituting nonwoven fabrics>

For the joint part of one elastic filament and non-woven fabric, under the magnification of 100 to 1000 times, the cross-section of the stretch sheet in the direction perpendicular to the stretching direction is observed by SEM, and the fibers constituting the elastic filament and the non-woven fabric are obtained respectively. The length of the joined portion of the elastic filament along the circumferential direction of the elastic filament (joined circumference), and the length of the non-joined portion of the elastic filament and the non-woven fabric constituent fiber along the circumferential direction of the elastic filament (unjoined Circumferential length), the bonding ratio of one elastic filament was obtained by the following formula. the

Bonding ratio of 1 elastic filament (%)={joined perimeter/(joined perimeter+unjoined perimeter)}×100

The average value of n=10 in each SEM observation was taken as the average joining ratio of elastic filaments and fibers constituting the nonwoven fabric. the

Returning to FIG. 1 , the stretchable sheet 10 of the present embodiment consists of a total of two nonwoven fabrics, the first nonwoven fabric 11 and the second nonwoven fabric 12, and a large number of elastic filaments sandwiched between the two nonwoven fabrics. 13 poses. Each elastic filament 13 is bonded to the first and second nonwoven fabrics 11 and 12 . The 1st nonwoven fabric 11 and the 2nd nonwoven fabric 12 may be the same kind of nonwoven fabric, and may be different kinds of nonwoven fabrics. The same kind of non-woven fabric mentioned here refers to the non-woven fabrics that have the same manufacturing process, the type of non-woven fabric constituent fibers, the fiber diameter or length of the constituent fibers, the thickness or unit area weight of the non-woven fabric, etc. cloth. When at least one of the above is different, it is called a different kind of nonwoven fabric. In addition, the elasticity in the present invention refers to the property that it can be stretched and returns to 125% or less of the original length when the force is released from a state stretched by 100% relative to the original length (the length is 200% of the original length). length. the

Each nonwoven fabric 11, 12 can be stretched. Each nonwoven fabric 11, 12 can be stretched in the same direction as the stretching direction of the elastic filament 13. The so-called elongation includes the following cases: (1) the case where the constituent fibers of the nonwoven fabrics 11, 12 are elongated by themselves; The three-dimensional structure formed by a plurality of fibers is structurally changed due to the combination of fibers, or the constituent fibers are broken, or the loose part of the fibers is stretched, thereby elongating the entire nonwoven fabric. the

The individual nonwovens 11 , 12 can also already be extensible in the state of the blank roll before joining with the elastic filaments 13 . Or it may be the following nonwoven fabric: although it is not extensible in the state of the blank roll before being joined with the elastic filament 13, after being processed in a manner that becomes extensible after being joined with the elastic filament 13 , thus becoming a stretchable non-woven fabric. Specific methods for making the nonwoven fabric stretchable include heat treatment, stretching between rolls, meshing stretching using tooth grooves or gears, stretching stretching using a tenter, and the like. In view of a preferable manufacturing method of the stretch sheet 10 described later, from the viewpoint of improving the conveyability of the nonwoven fabrics 11 and 12 when the elastic filaments 13 and the nonwoven fabrics 11 and 12 are melt-bonded, Preferably, the nonwoven fabrics 11, 12 are not stretchable in the state of the blank roll. the

Each of the nonwoven fabrics 11 and 12 is extensible and contains substantially inelastic fibers, thereby being substantially inelastic. the

Each elastic filament 13 is substantially continuous over the entire length of the stretch sheet 10 . The elastic filaments 13 contain elastic resin. The elastic filaments 13 are arranged so as to extend in one direction without intersecting each other. However, due to unavoidable fluctuations in the manufacturing conditions of the stretch sheet 10, it is acceptable that the elastic filaments 13 intersect inadvertently. The elastic filaments 13 may extend linearly or meander as long as they do not cross each other. The fact that the filaments do not cross each other means that there are almost no intersection points. If there is an intersection point, there will be a large number of fibers between the intersection points, but generally industrially, it is rare that the lengths of the fibers existing between the intersection points are uniform. If stretching is performed in a state where the lengths of the fibers existing between the intersections are different, stress is applied only to the shorter fibers included in the intersections, and even if many fibers are arranged, many fibers that do not participate in the stretching will be generated. When comparing fibers of the same weight, fibers with more intersection points have less shrinkage force. Therefore, costs are wasted. Considering the expansion and contraction only in the vertical direction, when fibers exist in the horizontal direction like a network, the horizontal fibers are not only useless, but also the above-mentioned intersection points are formed, and useless parts are similarly generated in the vertical fibers. The direction in which the elastic filaments 13 extend may coincide with the direction in which the first and second nonwoven fabrics 11 and 12 are produced, or may be perpendicular to the direction in which the nonwoven fabrics 11 and 12 are produced. When the elastic sheet 10 is manufactured according to the preferred manufacturing method described later, the extending direction of the elastic filament 13 is consistent with the moving direction of the first and the second nonwoven fabrics 11 and 12 during manufacture. the

The elastic filaments 13 are joined to the nonwoven fabrics 11 and 12 in a substantially unstretched state. These nonwoven fabrics 11, 12 are stretchable. Since the elastic filaments 13 are bonded to the nonwoven fabrics 11 and 12 in an unstretched state, the stretchable sheet 10 of this embodiment has the advantage that no slack (creep) due to elongation occurs, that is, the stretchability hardly decreases. . And, for example, when elastic filament 13 is stretched to 2 times and bonded to non-woven fabrics 11, 12, assuming that it returns to the original 1.3 times, it can only be stretched to 1.54 times from this state, but it can only be stretched to 1.54 times from this state. When pasting under the state, since the initial origin when the stretch sheet is stretched is different, it can be stretched to the extensible length of the non-woven fabrics 11, 12 or the maximum elongation rate of the elastic filament 13. advantage. the

Joining of the elastic filaments 13 to the nonwoven fabrics 11, 12 in the unstretched state also has the following advantages. The elastic sheet 10 of the present embodiment is produced, for example, by joining the elastic filaments 13 in a substantially unstretched state to the non-woven fabrics 11 and 12 in an unstretched state, and temporarily winding them up as a raw material roll, (at this time, The non-woven fabrics 11 and 12 in the non-stretched state joined with the elastic filaments 13 are non-stretchable), and the blank roll is sent out, and stretching processing (such as alveolar stretching) is carried out in another process, so that The non-woven fabrics 11 and 12 in the unstretched state become stretchable non-woven fabrics. In the above-mentioned state of the original roll, the original roll is not stretched and stretchable, and no external force is exerted on the elastic filament 13 . As a result, there is an advantage that slack due to elongation does not occur even if the above-mentioned raw material roll is stored for a long time. the

The elastic filaments 13 may be linear synthetic rubber threads or natural rubber. Alternatively, it may be a filament obtained by dry spinning (melt spinning) or wet spinning. Among them, the elastic filament 13 is preferably a filament obtained by melt spinning directly without temporarily winding or storing it, in view of a preferable manufacturing method described later. the

The elastic filaments 13 are preferably obtained by stretching molten resin ejected from a nozzle on a spinning line. By stretching, the polymers constituting the elastic filaments 13 are molecularly oriented in the longitudinal direction of the elastic filaments 13, so that the elongation/recovery ratio at 50% elongation described later increases and the hysteresis loss decreases. In addition, by stretching, thin elastic filaments can be obtained. From this viewpoint, the elastic filament 13 is preferably stretched 1.1 to 400 times, particularly preferably 4 to 100 times. On the other hand, in the aforementioned Patent Document 3, the elastic strand extruded from the die in a molten state is bonded to the sheet in an unstretched state, so the hysteresis loss of the elastic strand is not sufficiently small. In addition, in Patent Document 4, when stretching is performed, since the adhesive resin directly contacts the roll, there is a problem that the elastic strand is entangled with the roll. the

In particular, the elastic filaments 13 are preferably formed by stretching an elastic resin in a melted or softened state. Thereby, sufficiently fine filaments can be obtained, and the hand feeling is improved for the reason described later. In addition, by stretching the elastic resin in a melted or softened state, after laminating the nonwoven fabrics 11 and 12, the elastic filaments 13 at room temperature do not show the force to shrink, and become the same as the elastic filaments 13 in the In the non-stretched state, it is the same state as when the nonwoven fabrics 11 and 12 are joined. As the specific operation of stretching in this embodiment, the following operations can be cited: (1) melt spinning the resin used as the raw material of the elastic filament 13 to obtain an undrawn yarn, and then The elastic filament is heated again, and stretched at a state above the softening temperature (glass transition temperature Tg of the hard segment); (2) melting the resin that is the raw material of the elastic filament 13 Spinning is an operation in which the resulting molten fiber is directly stretched. When the stretch sheet 10 is manufactured according to a preferred manufacturing method described later, the elastic filaments 13 can be obtained by directly stretching the melted fibers obtained after melt spinning. the

The elastic filaments 13 obtained by stretching after spinning preferably have a diameter of 10 to 200 μm, particularly preferably 20 to 130 μm. This range is determined in consideration of the feel of the stretch sheet 10 and the productivity of the elastic filaments 13 . In detail, if the diameter of the elastic filaments 13 is too large, it is easy to feel the height difference caused by the elastic filaments 13 when touching the stretchable sheet 10 . This height difference has a negative effect on the feel of the stretch sheet 10 . From this point of view, the smaller the diameter of the elastic filaments 13, the easier it is to feel only the texture of the nonwoven fabrics 11 and 12, which is preferable. In addition, by reducing the translucency of the nonwoven fabric, it is possible to have a so-called body fluid color masking function, and in this sense, the elastic filaments 13 are also preferably thinner. In addition, in the elastic expressing treatment using toothed rollers described later, the diameter of the elastic filaments 13 is set to be equal to or less than the tooth-to-tooth gap between the toothed rollers (as a preferable gap, from the viewpoint of improving the durability of the teeth) From the viewpoint of increasing the draw ratio determined by the amount of engagement, the gap becomes smaller, less than 250 μm, more preferably less than 200 μm), and the elastic filament is less likely to be damaged (crack or break) during stretching, so it is preferable thin. The ratio of the diameter of the elastic filament to the gap is preferably 0.2 to 1, particularly preferably 0.2 to 0.5. In particular, the thinner the diameter of the elastic filament 13, the easier its manufacture becomes. In consideration of these, the diameter of the elastic filament 13 is preferably within the above range. the

The ratio of the diameter of the elastic filaments 13 in the thickness direction of the stretch sheet to the thickness of the stretch sheet 10 is preferably 1 to 30%, particularly preferably 5 to 12%, from the viewpoint of preventing the aforementioned height difference. the

The cross section of the elastic filament 13 may be circular, or may be oval or flat cross section according to different situations. For example, when the elastic sheet 10 is manufactured according to the manufacturing method described later, the cross-section of the elastic filaments 13 tends to be flattened. At this time, in the stretchable sheet 10, the elastic filaments 13 are preferably arranged such that the major axis of the flat shape is substantially in the same direction as the planar direction of the stretchable sheet 10, and the short axis is substantially in the same direction as the thickness direction of the stretchable sheet 10. direction. the

When the cross section of the elastic filament 13 is a flat shape, from the viewpoint of increasing the elastic properties, the bonding strength between the elastic filament 13 and the constituent fibers of the nonwoven fabrics 11, 12, and the masking function of the stretch sheet 10, the long axis The ratio of /short axis (average oblateness) is preferably 1.0 to 7.0, particularly preferably 1.1 to 3.0. The elastic filaments 13 having a flat cross section are arranged such that their major axis direction substantially coincides with the planar direction of the stretch sheet 10 . In addition, when the cross section of the elastic filament 13 is flat, the diameter of the elastic filament 13 means the average of the major axis diameter and the minor axis diameter. The major axis in the elastic filament 13 having a flat shape refers to the length of the longest orthogonal line in the outer circumference of the elastic filament 13 selected by microscopic observation. The short axis of the elastic filament 13 refers to the length of the short side when drawing a rectangle having both sides parallel to the long axis defined above and circumscribing the above-mentioned outer periphery. The above-mentioned values were measured for arbitrary elastic filaments at 5 points, and the average value of the flattening ratio was taken as the average flattening ratio, and the average value of the diameter values was taken as the diameter value of the elastic filaments. the

The elastic filaments 13 are also preferably colored in a color different from the colors of the first and second nonwoven fabrics 11 and 12 . In this way, the following pattern design effects can be achieved: the elastic filaments 13 can be seen through the first non-woven fabric 11 and/or the second non-woven fabric 12, and the stretchable sheet 10 presents a striped pattern. Such an effect becomes more remarkable especially when the thickness and basis weight of each nonwoven fabric are in the range mentioned later. the

From the viewpoint that the stretchable sheet 10 exhibits sufficient stretchability, exhibits a good cloth-like feel, and from the viewpoint of exhibiting the above-mentioned pattern design effect as required, the distance between adjacent elastic filaments 13 (relative to The distance between adjacent elastic filaments 13) is preferably 0.1 to 5 mm, particularly preferably 0.4 to 1 mm, on the condition that the diameter of the elastic filaments 13 is within the above-mentioned range. the

The elastic filaments 13 are joined to the respective nonwoven 11 , 12 over their entire length. In other words, the junction between the elastic filaments 13 and the nonwoven fabrics 11 and 12 is continuously formed over the entire length of the elastic filaments 13 in the longitudinal direction. Here, "bonded over its entire length" means that all the fibers in contact with the elastic filaments 13 (constituting fibers of the nonwoven fabrics 11, 12) do not need to be bonded with the elastic filaments 13, but are bonded to the elastic filaments. The elastic filaments 13 are bonded to the constituent fibers of the nonwoven fabrics 11 and 12 in a form in which there is no intentionally formed non-joint portion at 13 . By bonding the elastic filaments 13 to the respective nonwoven fabrics 11, 12 over their entire lengths, the bonding force between the elastic strands 13 and the respective nonwoven fabrics 11, 12 can be sufficiently increased. As a result, even if the stretchable sheet 10 is stretched, it is difficult to peel the elastic filaments 13 from the nonwoven fabrics 11 and 12 . If the elastic filament 13 is peeled off from each nonwoven fabric 11, 12, then in a natural state (relaxed state), floating occurs between the elastic filament 13 and each nonwoven fabric 11, 12, and the stretchable sheet 10 is easily formed. Wrinkles are generated on the top, thereby lacking the sense of unity as the stretch sheet 10 as a whole. the

As a joining form of the elastic filament 13 and the 1st and 2nd nonwoven fabrics 11 and 12, fusion bonding etc. are mentioned, for example. When the stretch sheet 10 is manufactured according to a preferred manufacturing method described later, the elastic filaments 13 are bonded to the respective nonwoven fabrics 11 and 12 by fusion bonding. Fusion bonding includes both the state where the elastic filaments and the fibers constituting the nonwoven fabrics 11 and 12 are fused and bonded to each other, or the state where either one is melted and the other is trapped and bonded. According to this method, without applying excessive heat to each of the nonwoven fabrics 11, 12, before the solidification of the elastic filaments 13 obtained by melt spinning, the elastic filaments 13 can be melt-bonded with the nonwoven fabrics. , so only the fibers that exist around the elastic filaments 13 are joined to the elastic filaments 13, and the fibers away from this position maintain the feel of the nonwoven fabrics 11, 12, so the feel of the stretchable sheet 10 is good Keep the advantages. At this time, before the nonwoven fabrics 11 and 12 are joined to the elastic filaments 13, an adhesive may be applied as an auxiliary joining means. Or, after each nonwoven fabric 11, 12 is bonded with the elastic filament 13, as an auxiliary bonding means, heat treatment (steam injection, heat embossing) or mechanical interweaving (needle punching, spun lace method) etc. can also be carried out. . However, these auxiliary joining means may impair the hand feeling of the obtained stretch sheet 10 or cause damage to the elastic filaments 13 . Therefore, it is preferable to melt-bond the elastic filaments 13 with the nonwoven fabrics 11, 12 by means of their fusion heat. However, when heat treatment by hot air blowing by the hot air method is used as an auxiliary bonding means, a sheet with high bonding strength of the nonwoven fabrics 11 and 12 can be obtained without impairing the handle of the obtained stretchable sheet 10. material, it is preferred from this point of view. the

The stretchable sheet 10 is stretchable in the same direction as the stretching direction of the elastic filaments 13 . The stretchability of the stretch sheet 10 is expressed by the elasticity of the elastic filaments 13 . When the stretchable sheet 10 is stretched in the same direction as the direction in which the elastic filaments 13 extend, the elastic filaments 13 and the first and second nonwoven fabrics 11 and 12 are stretched. Then, when the stretching of the stretch sheet 10 is released, the elastic filaments 13 shrink, and along with the shrinkage, the first and second nonwoven fabrics 11 and 12 return to the state before stretching. the

Unlike the sheets described in the aforementioned Patent Documents 1 and 2, in the stretch sheet 10 of the present embodiment, other elastic filaments bonded perpendicularly to the elastic filaments 13 do not exist. Therefore, even if the stretchable sheet 10 is stretched in the same direction as the direction in which the elastic filaments 13 extend, the stretchable sheet 10 is stretched without substantially shrinking in width. That is, the stretchable sheet 10 has substantially the same width in its longitudinal direction in its stretched state. As a result, workability becomes good when the stretch sheet 10 is conveyed in its stretched state and processed. In addition, when the stretchable sheet 10 is used as the outer packaging material of, for example, a pants-type diaper, it can effectively prevent the diaper from being shifted, dropped or wrinkled during wearing. In addition, considering the structure of the diaper and the movement of the user, although uneven elongation occurs in the width direction, there is almost no reduction in width at this time, and the diaper can be effectively prevented from shifting or wrinkling. From this point of view, the width reduction ratio when the stretch sheet 10 is stretched 1.5 times is preferably 1% to 10% of the width before stretching, particularly preferably 1% to 5%. The width reduction can be calculated by (1-width after stretching ÷ width before stretching)×100. The width after stretching was measured as follows. Cut the sample with a width of 50 mm in such a way that its length direction is roughly along the moving direction (the angle difference is within 15 degrees). The length exceeds 150mm. While keeping the width of the sample at 50 mm, both ends in the longitudinal direction of the sample were held at a holding interval of 150 mm. At this time, care is taken that the sample does not slack or elongate in its lengthwise direction. From this state, the holding gap was stretched to 1.5 times, and the width of the central portion in the longitudinal direction of the sample at this time was measured, and this value was defined as the width after stretching. the

2( a ) and ( b ) show longitudinal cross-sectional views along the extending direction of the elastic filaments 13 in the stretch sheet 10 according to one embodiment of the present invention. The embodiments shown in FIGS. 2( a ) and ( b ) are forms that are remarkably expressed when alveolar stretching is used in the elasticity expressing process in the manufacturing process of the stretch sheet 10 . Fig. 2(a) is a longitudinal sectional view of the stretchable sheet 10 in a natural state (relaxed state), and Fig. 2(b) is a longitudinal sectional view of the stretchable sheet 10 in an extended state. In a natural state, the stretch sheet 10 is in a wavy shape in which tops 14' and valleys 14" are alternately arranged. The tops 14' and valleys 14" are connected by ridges 15'. Compared with the thickness of the top 14' and the valley 14", the thickness of the ridge 15' is slightly smaller, so it is easier to transmit light than the top 14' and the valley 14". When looking down on the stretch sheet 10, the top 14', the ridges 15' and the valleys 14" extend in a direction perpendicular to the elongation direction of the stretch sheet 10. Therefore, in the stretch sheet 10, in its natural state , appear faintly by the ridge line portion 15 ' of light transmission easily and the top 14 ' and the valley part 14 that are difficult to transmit light than it and the transverse stripe pattern that produces. Elastic performance processing and other conditions become more apparent. 

That is, as shown in FIG. 2( b ), in the stretched sheet 10 in the stretched state, along the direction in which the elastic filaments 13 extend, the high basis weight portions 14 and the low basis weight portions 15 are alternately arranged. Each portion 14 , 15 extends in a belt shape in a direction perpendicular to the direction in which the elastic filament 13 extends. The high basis weight portions 14 and the low basis weight portions 15 are alternately arranged at a constant period. As for the high basis weight portion 14 , portions protruding toward the upper side of the sheet 10 and portions protruding toward the lower side of the sheet 10 are alternately arranged. The high basis weight portion 14 protruding toward the upper side of the sheet 10 comes from the top 14' in the sheet 10 in its natural state shown in Fig. 2(a). And the high unit area weight portion 14 protruding to the underside of the sheet 10 comes from the valley portion 14 ″ in the sheet 10 in the natural state shown in FIG. 2( a). In addition, the low unit area weight portion 15 comes from FIG. 2 (a) shows the ridge line portion 15' in the sheet 10 in the natural state. In the high unit area weight part 14 and the low unit area weight part 15, due to their difference in unit area weight, the light transmission degree There are differences. As a result, the stretch sheet 10 presents a horizontal striped pattern extending in a direction perpendicular to the direction of extension of the elastic filament 13, and the pattern design is high. Especially, as previously mentioned, the stretch sheet 10 also presents a pattern composed of elastic The striped pattern produced by the filament 13, so the stretchable sheet 10 also presents a grid-like pattern formed by a combination of the striped pattern and the striped pattern produced by the high unit area weight part 14 and the low unit area weight part 15, and the pattern design Improve further.In addition, as shown in Figure 2 (a) and (b), as a preferred embodiment of the present invention, the protruding part of the upper side or the lower side of the sheet 10 is filled with fibers.

The high basis weight portion 14 has a larger basis weight and a larger thickness than the low basis weight portion 15 . Accordingly, the light transmission degree differs between the high basis weight portion 14 and the low basis weight portion 15 , and a striped pattern appears due to the difference. The high basis weight portions 14 are substantially equal in width to each other, and similarly, the respective low basis weight portions 15 are also substantially equal in width to each other. the

The thickness of the high basis weight portion 14 is preferably 0.3 to 10 mm, particularly preferably 0.5 to 1 mm. The thickness of the low basis weight portion 15 is preferably 0.1 to 3 mm, particularly preferably 0.2 to 0.6 mm, from the viewpoint of stretchability and air permeability. The thickness is measured by leaving the stretchable sheet 10 in an environment of 20±2° C. and 65±5% RH without a load for more than 2 days, and then obtains it by the following method. First, the stretchable sheet 10 was stretched 1.5 times in the elongation direction, and in this state, it was sandwiched between flat plates with a load of 0.5 cN/cm ² . The cross-section was observed with a microscope at a magnification of 50 to 200 times, and the average thickness in each field of view was determined, and the above-mentioned thickness was obtained as an average value of thicknesses in three fields of view. The high basis weight portion 14 and the low basis weight portion 15 can be easily formed when the stretch sheet 10 is produced by a production method described later.

Next, constituent materials of the first and second nonwoven fabrics 11 and 12 and the elastic filaments 13 constituting the stretch sheet 10 will be described. Substantially inelastic fibers can be used as fibers constituting each of the nonwoven fabrics 11 and 12 . Examples thereof include fibers made of polyethylene (PE), polypropylene (PP), polyester (PET or PBT), polyamide, and the like. The fibers constituting each of the nonwoven fabrics 11 and 12 may be short fibers or long fibers, and may be hydrophilic or hydrophobic. In addition, core-sheath type or side-by-side composite fibers, split fibers, irregular cross-section fibers, crimped fibers, heat-shrinkable fibers, etc. can also be used. These fibers may be used alone or in combination of two or more. Each nonwoven fabric 11, 12 may be a nonwoven fabric of continuous filaments or short fibers. In particular, each of the nonwoven fabrics 11 and 12 is preferably a short fiber nonwoven fabric from the viewpoint of making the stretchable sheet 10 a thick bulky sheet. When the stretchable sheet 10 is used as a member in contact with the skin, a short-fiber nonwoven fabric with a good feel can be used on the skin-contact side, and a high-strength continuous filament nonwoven fabric can be used on the opposite side. the

Each of the nonwoven fabrics 11 and 12 preferably has constituent fibers composed of two or more components of a low-melting point component and a high-melting point component. At this time, the constituent fibers are bonded at fiber intersections by thermal fusion bonding of at least a low-melting point component. As the core-sheath type conjugate fiber composed of two or more low-melting-point components and high-melting-point components, it is preferable that the core is made of high-melting point PET or PP, and the sheath is made of low-melting point PET, PP, or PE. In particular, when these conjugate fibers are used, the fusion bonding with the elastic filaments 13 becomes stronger, and the peeling between the two is less likely to occur, which is preferable. the

The thickness of each of the nonwoven fabrics 11 and 12 is preferably 0.05 to 5 mm, more preferably 0.1 to 1.0 mm, and even more preferably 0.15 to 0.5 mm. The measurement of the thickness can be carried out as follows: clamp between the flat plates with a load of 0.5 cN/cm ² , observe the cross-section of the stretchable sheet 10 with a microscope at a magnification of 50 to 200 times, and obtain the average thickness in each field of view respectively, and use three The above-mentioned thickness is obtained in the form of the average value of the thickness of each field of view. The thickness of the entire sheet can be obtained by measuring the distance between the flat plates. The weight per unit area of each of the nonwoven fabrics 11 and 12 is preferably 3 to 100 g/m ² , particularly preferably 10 to 30 g/m ² , from the viewpoint of texture, thickness, and pattern design.

It is preferable that each of the nonwoven fabrics 11 and 12 is composed of substantially inelastic fibers from the viewpoint of texture and tackiness. The ratio of the non-elastic fiber in the nonwoven fabric may be 70% by weight or more, preferably 90% by weight or more, and more preferably 100% by weight. In addition, the substantially inelastic fibers may contain an elastic resin in the inelastic resin, and the ratio of the inelastic resin may be 70% by weight or more, preferably 90% by weight or more, more preferably 100% by weight. In particular, as the inelastic fiber, it is preferable to use a fiber having a different thickness in the longitudinal direction (hereinafter, the fiber is referred to as an indeterminate fiber). That is, the indeterminate fiber has a portion with a large fiber cross-sectional area (diameter) and a portion with a small fiber cross-sectional area (diameter) when viewed along its length direction. In indeterminate fibers, the diameter (cross-sectional area) can vary continuously from the smallest part to the largest part. Alternatively, the diameter (cross-sectional area) of the fiber may change substantially in steps like the necking phenomenon observed in the drawing step of the undrawn yarn. An example of an inelastic fiber having a state where the diameter (cross-sectional area) of the fiber changes approximately stepwise is shown in FIG. 3 . the

Non-elastic fibers are made of fibers with constant fiber diameter and high elongation (for example, the maximum elongation of the fiber is 80-800%, especially 120-650%), which can obtain a stretchable sheet with high maximum strength. It is preferable from the viewpoint of material 10. The elongation of the fiber is based on JIS L-1015, based on the measurement under the following conditions: the measured ambient temperature and humidity are 20±2°C, 65±5%RH, the distance between the clamps of the tensile testing machine is 20mm, and the pulling speed It is 20mm/min. In addition, the elongation rate is measured by collecting fibers from the manufactured non-woven fabric. If the clamp distance cannot be set at 20 mm, that is, when the measured fiber length is less than 20 mm, set the clamp distance at 10 mm or 5 mm. Determination. the

The aforementioned high-elongation fibers are preferably low-stretch non-elastic fibers. When the stretch sheet 10 of this embodiment is manufactured by using low-stretch non-elastic fibers as raw materials according to the manufacturing method described later, stretching the low-stretch fibers during the elastic expression treatment process can create a stretch in the fibers. A finer fraction is produced, thereby forming the aforementioned unsizing fibers. As a result, in the process of expressing the elasticity of the stretch sheet according to the present embodiment, the nonwoven fabric becomes structurally stretchable, and by stretching the fibers, the entire structure of the nonwoven fabric becomes easily stretchable, which will affect the stretchability of the stretchable sheet. The damage of the joints between fibers with non-caliber diameters and the joints between the non-woven fabrics 11 and 12 and the elastic filaments 13 is minimized, and the strength of the stretch sheet 10 can be improved while maintaining the stretch performance. That is, a stretchable sheet 10 having both high elongation and high strength can be obtained. In addition, the bond between the above-mentioned non-caliber fibers is hardly broken during the elastic expressing process, and this also has an effect of making it difficult for the nonwoven fabrics 11 and 12 to fluff. This is advantageous from the viewpoint of improving the appearance of the stretch sheet 10 of this embodiment. On the other hand, in the elastic-stretch composite sheet described in Patent Document 5 described in the Background Art section, since the constituent fibers are difficult to stretch in the stretching step, welding or mechanical entanglement of the fibers cannot be achieved. As a result, the strength of the sheet decreases, and high elongation and high strength cannot be achieved at the same time. the

In addition, by using the above-mentioned low-drawn fiber as a raw material, the number (length) of thin fibers substantially increases compared with that before fiber drawing. Thereby, the opacity of the stretch sheet 10 of this embodiment improves. From the viewpoint of improving the masking performance of the body fluid absorbed by the absorbent body that is difficult to see through the front sheet, the opacity of the stretch sheet 10 is improved when, for example, the stretch sheet 10 is used as a sanitary napkin or a disposable diaper, etc. The use of the front sheet of an absorbent article is advantageous. the

In addition, if the thickness of the non-diameter fibers is periodically changed, there is an additional effect that the surfaces of the nonwoven fabrics 11 and 12 are finely undulated, and the skin feel becomes good. At this time, the period of change, that is, the distance between the thicker part and its adjacent thicker part is preferably 0.5 to 10 mm, particularly preferably 2 to 5 mm. This period can be measured from microscopic observation of each nonwoven fabric 11 , 12 . Here, the measurement of the diameter of the indeterminate fiber can be performed in the following procedures (1) to (5). the

(1) The nonwoven fabric 11 or the nonwoven fabric 12 is sampled from an area of 5 mm×5 mm or more on the surface of the stretch sheet 10 . The samples at this time may be collected by cutting the nonwoven fabrics 11 and 12 from the elastic filaments 13 , or may collect the stretchable sheet 10 as a whole. the

(2) The collected sample is fixed on the sample stage for SEM observation. At this time, in order to facilitate observation of the sample, the sample may be fixed on the sample stand with double-sided tape while stretching the sample to such an extent that the structure of the sample is not broken (to the extent that the slack of the nonwoven fabric disappears). The amount of stretching at this time is set to be equal to or less than the stretching ratio at which the precursor of the stretchable sheet 10 is stretched in the stretching step, for example, when the elasticity expressing treatment step is used in the manufacturing step of the stretchable sheet 10 . the

(3) SEM observation was performed at a magnification of 200. The field of view area at one point was about 0.4 mm×0.4 mm or more, and five points were observed. the

(4) Randomly extract fibers, and measure the diameter at intervals of 10 μm in the fiber axial direction in units of 0.1 μm, and measure more than 20 places in total (fusion bonding points between fibers or broken parts are not included in the measurement). Four or more fibers were measured in each visual field, and a total of 20 fibers in five visual fields were measured. the

(5) From these values, the respective maximum diameters and minimum diameters of 20 fibers are selected. the

The difference between the maximum diameter and the minimum diameter of one fiber is 1 μm or more, and when the relationship between the axial position of the fiber and the change in diameter is plotted, a fiber with two or more maximum positions or minimum positions is called indeterminate. fiber. the

From the viewpoint of making the above effects more remarkable, the thickness of the indeterminate fiber is preferably 2 to 15 μm at the thinnest portion, more preferably 5 to 12 μm, and preferably 10 to 40 μm at the thickest portion, more preferably 12～30μm. The difference between the maximum diameter and the minimum diameter of the indeterminate fiber is preferably 3 μm or more, particularly preferably 5 μm or more, particularly preferably 10 μm or more. In addition, the ratio of the fiber diameter defined by "maximum fiber diameter/minimum fiber diameter" is preferably 1-15, more preferably 1.2-10, even more preferably 2-5. the

The non-sizing fibers preferably have an interfiber fusion bond strength higher than the 100% elongation strength of the non-sizing fibers. Therefore, in the elastic expressing treatment process when the stretchable sheet 10 is produced, when the stretchable sheet 10 before stretching is stretched to perform the elastic expressing process, it is difficult to cause the elastic sheet 10 before the elastic expressing treatment to be stretched. Breakage of fusion bonding points between fibers is preferable in that the strength of the stretch sheet 10 obtained through the above-mentioned elasticity expressing treatment step is less likely to decrease compared with the strength of the stretch sheet 10 before expressing elasticity. The fusion point strength can be measured in accordance with the description in paragraph [0040] of the applicant's prior application, Japanese Patent Application Laid-Open No. 2004-218183. The strength at 100% elongation can be measured using a tensile tester under the conditions of a distance between chucks of 20 mm and a pulling speed of 20 mm/min. the

The aforementioned low-stretch non-elastic fiber includes both: a fiber drawn at a low draw ratio after spinning and an undrawn fiber, ie, an undrawn fiber. As the low-stretch fiber, it is preferable to use a fiber having an elongation of 80 to 800% as described above, and it is particularly preferable to use a fiber having an elongation of 120 to 650%. By using a low-stretch fiber having an elongation in this range, the fiber can be smoothly stretched in a stretching device 22 shown in FIG. 5 described later, and an indeterminate fiber can be easily formed. The fiber diameter of the low-stretched fibers is preferably 10 to 35 μm, particularly preferably 12 to 30 μm. the

As previously stated, non-sizing fibers are preferably derived from low-stretch fibers having a constant fiber diameter. In this case, the low-stretch fiber may be a fiber composed of a single raw material, or may be a composite fiber using two or more raw materials, such as a core-sheath composite fiber or a side-by-side composite fiber. In consideration of the ease of bonding of non-diameter fibers to each other and the ease of bonding of the nonwoven fabrics 11 and 12 and the elastic filaments 13, it is preferable to use a conjugate fiber. In the case of a core-sheath composite fiber, the core is preferably polyester (PET or PBT), polypropylene (PP), and the sheath is low-melting polyester (PET or PBT), polypropylene (PP), or polyethylene. (PE). In particular, when these conjugate fibers are used, when the elastic filaments 13 contain a polyolefin-based elastomer, the thermal fusion bonding between the elastic filaments 13 and the constituent fibers of the nonwoven fabrics 11, 12 is enhanced, and it is difficult to It is preferable from the viewpoint of causing layer peeling. the

The indeterminate fibers may be short fibers such as staple fibers or long fibers such as continuous filaments. In view of a preferable manufacturing method of the stretch sheet 10 described later, short fibers are preferably used. Additionally, non-sizing fibers can be either hydrophilic or hydrophobic. the

Each of the nonwoven fabrics 11 and 12 may be composed only of indeterminate fibers, or may contain other non-elastic fibers of constant diameter in addition to indeterminate fibers. Examples of other inelastic fibers include the aforementioned fibers. When each of the nonwoven fabrics 11 and 12 contains other non-elastic fibers of constant diameter in addition to the fibers of indeterminate diameter, the compounding amount of the other non-elastic fibers is preferably 1 to 30% by weight, particularly preferably 5 to 20% by weight. the

It is particularly preferable that the non-caliber fibers be contained in both of the two nonwoven fabrics 11 , 12 , but may be contained in only one of the two nonwoven fabrics 11 , 12 . the

The elastic filaments 13 are, for example, made of elastic resin such as thermoplastic elastomer or rubber as described above. The elastic filaments 13 are long fibers having elasticity. In particular, when a thermoplastic elastomer is used as a raw material for the elastic resin, it can be melt-spun using an extruder in the same way as a common thermoplastic resin, and the obtained filaments are easily thermally melt-bonded, so it is suitable for this embodiment. stretchable sheet. Examples of thermoplastic elastomers include SBS (styrene-butadiene-styrene), SIS (styrene-isoprene-styrene), SEBS (styrene-ethylene-butadiene-styrene), Styrene-based elastomers such as SEPS (styrene-ethylene-propylene-styrene), olefin-based elastomers (ethylene-based α-olefin elastomers, propylene-based elastomers copolymerized with ethylene/butylene/octene, etc.) , Polyester-based elastomers, polyurethane-based elastomers. These may be used alone or in combination of two or more. In addition, core-sheath type or side-by-side type conjugate fibers made of these resins can also be used. In particular, it is preferable to use styrene-based elastomers, olefin-based elastomers, or combinations thereof from the viewpoints of formability, stretchability, and cost of the elastic filaments 13 . the

The preferred combination of the elastic filaments 13 and the fibers constituting the nonwoven fabrics 11 and 12 is the following combination: the elastic filaments 13 use SEBS resin or SEPS resin, and the constituent fibers of the nonwoven fabrics 11 and 12 use PP/PE core sheath composite fiber or PET/PE core-sheath composite fiber. By employing this combination, fusion bonding can be reliably performed. In addition, since the core has a high melting point, the fibers are incompletely fused (the core remains) during fusion bonding, and a stretchable sheet 10 with high maximum strength can be obtained. the

In particular, as the elastic filament 13, it is preferable to use an elastic filament formed of a resin composition containing an A1-B-A2 type triblock copolymer composed of Polymer blocks A1 and A2 mainly composed of vinyl aromatic polymers, and polymer block B mainly composed of polyolefins are formed. the

The sum of the weight average molecular weights of the polymer blocks A1 and A2 as measured by gel permeation chromatography (GPC) is preferably 14000 to 20000, more preferably 14000 to 18000, and the polymer block B as measured by the GPC method The weight average molecular weight is preferably 40,000 to 80,000, more preferably 40,000 to 70,000. In this specification, the weight average molecular weight determined by GPC method is determined under the following measurement conditions: column: TSKgel G-2000H; column temperature: 40°C; mobile phase: tetrahydrofuran (THF); flow rate: 1.0mL/min; Sample concentration: 10mg/5mL-THF; injection volume: 500μL; and the value of the above-mentioned weight-average molecular weight was obtained by converting polystyrene. As an analysis sample, a sample obtained by the following pretreatment operation was used: 10 mg of the sample was dissolved in 5 mL of tetrahydrofuran at room temperature for 10 minutes, and then filtered through a sintered filter with a pore size of 0.45 μm. the

When the resin composition contains two or more types of A1-B-A2 type triblock copolymers, for example, the above-mentioned "weight average molecular weight of the polymer block A1 measured by GPC" is used as two or more types of A1-B- The polymer block A1 of each type A2 triblock copolymer is obtained by the weight average of the weight average molecular weight measured by the GPC method. That is, for example, the resin composition contains (A1'-B'-A2') and (A1"-B'-A2") two A1-B-A2 type triblock copolymers as A1-B-A2 type triblock copolymers. Segment copolymer, and the percentage content of (A1'-B'-A2') (A1'-B'-A2' contains two or more A1-B-A2 type triblock copolymers contained in the resin composition When the percentage content in the total amount of (A1 "-B"-A2") is 80% by weight and the percentage content of (A1"-B"-A2") is 20% by weight, the weight average of the above "polymer block A1 measured by GPC method Molecular weight" is obtained by the following formula.

(The weight-average molecular weight measured by the GPC method of the polymer block A1')×0.8+(the weight-average molecular weight measured by the GPC method of the polymer block A1″)×0.2

When the resin composition contains two or more A1-B-A2 type triblock copolymers, for the above "weight average molecular weight of polymer block A2 measured by GPC method" and "polymer block B measured by GPC method The weight-average molecular weight of ", also obtain respectively according to the above-mentioned example of polymer block A1. the

In addition, when the resin composition contains two or more types of A1-B-A2 type triblock copolymers, the above-mentioned "total weight average molecular weight of each of the polymer blocks A1 and A2 measured by the GPC method" is obtained as above The total of the weight averages of the above-mentioned weight average molecular weights of the respective polymer blocks A1 and A2. the

The elastic filament 13 is formed of a resin composition containing an A1-B-A2 type triblock copolymer satisfying the above-mentioned physical properties, has excellent spinning formability, and does not cause filament breakage even when the diameter is small. And it can be ejected from the spinning nozzle without twists and turns. the

The polymer block A1 is mainly composed of a vinyl aromatic polymer. Examples of the vinyl aromatic constituting the vinyl aromatic polymer include styrene, p-methylstyrene, m-methylstyrene, p-tert-butylstyrene, α-methylstyrene, chlorinated Methylstyrene, p-tert-butoxystyrene, dimethylaminomethylstyrene, dimethylaminoethylstyrene, vinyltoluene, 1-vinylnaphthalene, 4-propylstyrene, 4- Cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl)styrene, and the like. The vinyl aromatic polymer may be composed of one type of these vinyl aromatics, or may be composed of two or more types. Among these vinyl aromatics, styrene is preferable from the viewpoint of ease of polymerization and versatility. the

The content of the vinyl aromatic polymer in the polymer block A1 is preferably 90 to 100% by weight, more preferably 95 to 100% by weight, based on the entire structural unit of the polymer block A1. the

The polymer block A1 may contain a conjugated diene compound polymer in addition to the vinyl aromatic polymer. Examples of the conjugated diene compound constituting the conjugated diene compound polymer include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl- 1,3-butadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, phenylbutadiene, 4,5-diethyl-1,3-octadiene , 3-butyl-1,3-octadiene, etc. The conjugated diene compound polymer may be composed of one type of these conjugated diene compounds, or may be composed of two or more types. the

The content of the conjugated diene compound polymer in the polymer block A1 is preferably 0 to 10% by weight, more preferably 0 to 5% by weight, based on the entire structural unit of the polymer block A1. the

The weight average molecular weight measured by the GPC method of polymer block A1 becomes like this. Preferably it is 7000-10000, More preferably, it is 7000-9000. the

As the polymer block A2, the same block as that of the above-mentioned polymer block A1 can be used. The description of the polymer block A1 can be appropriately applied to the points that are not particularly described for the polymer block A2. In the A1-B-A2 type tri-block copolymer, the structures of the polymer block A1 and the polymer block A2 may be the same or different. the

In particular, polymer blocks A1 and A2 are preferably both styrene. That is, the elastic filament 13 preferably has a configuration including only polystyrene as the polymer block A1 and only polystyrene as the polymer block A2. the

The total content of the polymer blocks A1 and A2 in the A1-B-A2 type triblock copolymer is preferably 15 to 40% by weight, more preferably, relative to the entire structural unit of the A1-B-A2 type triblock copolymer It is 18 to 30% by weight. the

In addition, as mentioned above, when the polymer blocks A1 and A2 are both polystyrene, the ratio of the polymer block A1 and the polymer block A2 in the A1-B-A2 type triblock copolymer is calculated by weight ratio Preferably it is (A1/A2)=0.8-1.2, More preferably, it is (A1/A2)=0.9-1.1. the

The polymer block B is mainly composed of polyolefin. Examples of the olefin constituting the polyolefin include isoprene, butadiene, ethylene, propylene, butene and the like. The olefin constituting the polymer block B may consist of one type of these olefins, or may consist of two or more types. Among these olefins, ethylene and propylene are preferable from the viewpoint of weather resistance and stretchability. the

The content of the polyolefin in the polymer block B is preferably 90 to 100% by weight, more preferably 95 to 100% by weight, based on the entire structural unit of the polymer block B. the

The polymer block B may contain other polymers derived from other polymerizable monomers that can be polymerized with polyolefins in addition to the above-mentioned polyolefins. As this other polymerizable monomer, styrene is mentioned, for example. The above-mentioned other polymers that can be polymerized with polyolefins that constitute the polymer block B may be composed of one type of these other polymerizable monomers, or may be composed of two or more types. the

The content of the above-mentioned other polymers in the polymer block B is preferably 0 to 10% by weight, more preferably 0 to 5% by weight, based on the entire structural unit of the polymer block B. the

Specific examples of the polymer block B include polyisoprene, polybutadiene, poly(ethylene-propylene), poly(ethylene-butylene), and the like. Among them, poly(ethylene-propylene) is preferable in terms of weather resistance and stretchability. the

The content of the polymer block B in the A1-B-A2 type triblock copolymer is preferably 60 to 85% by weight, more preferably 70 to 70% by weight relative to the entire structural unit of the A1-B-A2 type triblock copolymer. 82% by weight. the

Specific examples of preferred A1-B-A2 type triblock copolymers include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block Copolymer (SIS), Styrene-ethylene-butylene-styrene block copolymer (SEBS) as a hydrogenated product of SBS, Styrene-ethylene-propylene-styrene block copolymer ( SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), etc. Among them, SEBS, SEPS, and SEEPS are preferable because elastic filaments 13 excellent in thermal stability and weather resistance can be obtained. the

Commercially available items can also be used as the A1-B-A2 type triblock copolymer. As a commercially available product of the A1-B-A2 type triblock copolymer preferably used in the present invention, for example, the trade name "Kraton" of Kraton Polymers, the trade name "Tuftec" and "Tuftec" of Asahi Kasei Chemical Co., Ltd. TUFPRENE", Kuraray's trade name "SEPTON", "Hybrar" series, etc. the

The A1-B-A2 type triblock copolymer can be synthesized by, for example, the following procedure. First, a vinyl aromatic compound is added to a hydrocarbon solvent such as cyclohexane, and anionic polymerization is performed using an organic lithium compound or metal sodium as an initiator to obtain a polymer block A1. Then, an olefin monomer was added and polymerized to obtain a polymer block A1-B. When the olefin monomer is a conjugated diene, the double bond based on the conjugated diene of the copolymer is hydrogenated to obtain the target polymer block A1-B. From the viewpoint of heat resistance and weather resistance, the hydrogenation rate based on the double bond of the conjugated diene is preferably 80% or more of the double bond of the conjugated diene, particularly preferably 90% or more. The hydrogenation reaction can be carried out using noble metal catalysts such as platinum and palladium, organic nickel compounds, organic cobalt compounds, or composite catalysts of these compounds and other organic metal compounds. The hydrogenation rate can be calculated by the iodine value measurement method. Then, a vinyl aromatic compound is added and polymerized to obtain polymer blocks A1-B-A2. the

The above-mentioned resin composition constituting the elastic filament 13 may be constituted by only containing the above-mentioned A1-B-A2 type triblock copolymer, and may, as required, include a mixture other than A1-B-A2 within the scope of not impairing the purpose of the present invention. In addition to the type triblock copolymer, it is composed of one or two or more other resins. When the above-mentioned resin composition contains A1-B-A2 type triblock copolymer and other resins, the content of A1-B-A2 type triblock copolymer in the resin composition is preferably 90 to 100% by weight, more preferably It is 95 to 100% by weight. However, from the viewpoint of maximizing the spin formability and stretchability, the resin composition is preferably composed of only the A1-B-A2 type triblock copolymer. the

In addition, the aforementioned resin composition may contain one type of A1-B-A2 type triblock copolymer, or may contain two or more types of A1-B-A2 type triblock copolymers having different structures. the

When the above-mentioned resin composition contains other resins besides the A1-B-A2 type triblock copolymer, as the other resins, for example, rubber, or polyolefin-based elastomers, polyester-based elastomers, polyurethanes, etc., can be used. Thermoplastic elastomers such as elastomers, etc. In addition, resins other than thermoplastic elastomers, for example, thermoplastic resins such as polyethylene and polypropylene, and the like can be used. These can also be used in combination of 2 or more types. the

The above-mentioned resin composition can be obtained by melt-mixing the A1-B-A2 type triblock copolymer, or the A1-B-A2 type triblock copolymer and the above-mentioned other resins by various known methods. For example, the above-mentioned components are simultaneously or sequentially loaded into a Henschel mixer, a V-type mixer, a drum mixer, a ribbon mixer, etc. for mixing, and then extruded with a single-screw extruder or a multi-screw extruder. kneading machine, kneader, internal kneader and other kneading equipment to obtain the above-mentioned resin composition. the

In addition to the above-mentioned resin components (A1-B-A2 type triblock copolymer, other resins), the above-mentioned resin composition may also contain a plasticizer (such as a paraffinic oil , paraffin wax, naphthene oil, ethylene-α-olefin oligomer, low molecular weight polyethylene, etc.), weathering stabilizer, heat stabilizer, antistatic agent, lubricant, slip agent, nucleating agent, Flame retardants, pigments, dyes, inorganic or organic fillers, etc. the

When the above-mentioned resin composition is heated and melted at a temperature of 245°C, when it is ejected from a cylindrical nozzle with an inner diameter of 0.45mm and a length of 4.5mm at a discharge speed of 8.4m/min, the maximum melt tension is The value is preferably 0.06 to 0.20 cN, more preferably 0.07 to 0.15 cN. Fig. 4 shows the method of measuring the melt tension. The upward force applied to the load cell shown in FIG. 4 was measured, and the measured value was regarded as the melt tension. When the maximum value of the melt tension of the resin composition constituting the elastic filaments 13 falls within the above range, the spinning formability can be improved. The adjustment of the melt tension can be performed by adding, for example, a plasticizer (paraffin wax, etc.), rubber, thermoplastic resin, or the like. The melt tension of the resin composition constituted as described above is within the above range. the

The apparent basis weight of the elastic filaments composed of a large number of elastic filaments 13 disposed between the two nonwoven fabrics 11, 12 is preferably 4 to 30 g/momentum from the viewpoint of stretchability, texture, thickness, and cost. m ² is particularly preferably 6 to 15 g/m ² .

Next, a preferable manufacturing method of the stretch sheet 10 of the present embodiment will be described with reference to FIG. 5 . In this manufacturing method, a large number of elastic filaments 13 in a molten state spun from a spinning nozzle 16 are drawn and stretched at a predetermined speed, and before the elastic filaments 13 are solidified, 13 are arranged in one direction without intersecting each other so that the elastic filaments are melt-bonded with the non-woven fabrics 11 and 12, and then the composite 19 that is melt-bonded with the elastic filaments 13 is made along the length of the elastic filaments 13 The non-woven fabric composite 19 is stretchable by performing elastic expressing treatment in the extending direction. the

The spinning nozzle 16 is provided on a spinning head 17 . The spinning head 17 is connected to the extruder. The resin may also be supplied to the spinning head 17 by a gear pump. The elastic resin melt-kneaded by this extruder is supplied to the spinning head 17 . On the spinning head 17, a large number of spinning nozzles 16 are arranged in a line in a straight line. The spinning nozzles 16 are arranged along the width direction of the first and second nonwoven fabrics 11 and 12 . The distance between adjacent spinning nozzles 16 corresponds to the distance between the elastic filaments 13 in the target stretch sheet 10 . The spinning nozzle 16 is generally circular, and its diameter (inner diameter) will affect the diameter and draw ratio of the elastic filament 13 . From this viewpoint, the diameter (inner diameter) of the spinning nozzle 16 is preferably 0.1 to 2 mm, particularly preferably 0.2 to 0.6 mm. In order to improve the bonding strength with the non-woven fabrics 11, 12, improve the spinnability of the elastic filament 13, and improve the stretching properties of the stretchable sheet 10, the elastic filament 13 can also be made into a composite form (side-by-side, core-sheath , island structure). Specifically, a combination of a PP-based elastomer resin and a styrene-based elastomer resin is preferable. the

The elastic filaments 13 in the molten state spun out are merged with the first nonwoven fabric 11 and the second nonwoven fabric 12 spun out at the same speed from the stock roll, and then clamped between the two nonwoven fabrics 11, 12. time and pull at the specified speed. The pulling speed of the elastic filament 13 is consistent with the spinning speed of the two non-woven fabrics 11 and 12 . The pulling speed of the elastic filament 13 will affect the diameter and stretching ratio of the elastic filament 13 . The tension applied to the elastic filaments 13 by stretching prevents the elastic filaments 13 from flying away due to wind or static electricity when the elastic filaments 13 are bonded to the nonwoven fabrics 11 and 12 . Accordingly, the elastic filaments can be arranged in one direction without intersecting each other. From these viewpoints, the pulling speed of the elastic filament 13 is preferably adjusted to a draw ratio of 1.1 to 400 times, particularly 4 to 100 times, and further 10 to 100 times, relative to the resin ejection speed in the spinning nozzle hole. 80 times. the

The elastic filaments 13 merge with the first and second nonwoven fabrics 11 and 12 before they are solidified, that is, in a melt-bondable state. As a result, the elastic filaments 13 are fusion bonded to the above-mentioned nonwoven fabrics 11 and 12 in a state sandwiched between the first and second nonwoven fabrics 11 and 12 . That is, the elastic filaments 13 are drawn and stretched while the elastic filaments before solidification are melt-bonded to the conveyed nonwoven fabrics 11 and 12 . When the elastic filaments 13 are melt-bonded, no heat is applied to the first and second nonwoven fabrics 11 and 12 from the outside. That is, the elastic filaments 13 and both nonwoven fabrics 11 and 12 are melt-bonded only by the heat of fusion generated by the melt-bondable elastic filaments 13 . As a result, only the fibers present around the elastic filaments 13 among the constituent fibers of the nonwoven fabrics 11 and 12 are melt-bonded with the elastic filaments, and the fibers present far from the position are not melt-bonded. As a result, the heat applied to both nonwoven fabrics 11 and 12 is kept to a minimum, so that the original good texture of the nonwoven fabric itself can be maintained. Thereby, the texture of the stretchable sheet 10 obtained becomes favorable. the

Before the elastic filament 13 in the molten state spun from the spinning nozzle 16 contacts the nonwoven fabrics 11, 12, the moving distance L of the elastic filament 13 from the tip 16a of the spinning nozzle 16 (the tip of the spinning nozzle 16 16a and the shortest distance between the contact portions 11a, 12a of the elastic filaments 13 in the molten state and the nonwoven fabrics 11, 12 when they first contact, see FIG. By setting the moving distance L of the elastic filaments 13 in the molten state to be 600 mm or less, the elastic filaments and the nonwoven fabric can be reliably melt-bonded before the elastic filaments in the molten state are solidified, so that the gap between the layers can be obtained more reliably. A stretch sheet having an excellent balance between joint strength and stretch characteristics, that is, the joint strength between the elastic filaments and the nonwoven fabric in the stretch sheet is 10 cN/25 mm or more, and the elastic resin in the stretch sheet has a density per unit area The 25% recovery strength by weight is 1.0 cN/{50 mm·(g/m ² )} or more. In addition, by making the moving distance L of the molten elastic filament 13 100 mm or more, the viscosity of the elastic resin is increased by cooling the molten elastic filament 13, so that the elastic filament 13 is moved between the nip rollers 18a, 18b. The space is difficult to be crushed. Thereby, the average bonding ratio between the elastic filaments 13 and the fibers constituting the extensible nonwoven fabrics 11 and 12 can be set within the aforementioned preferable range. On the other hand, by making the moving distance L of the elastic filament 13 in the molten state 600 mm or less, the filament will not be scattered due to static electricity or wind, and the frequency of occurrence of adhesion, overlap, or filament breakage between the filaments Since the distance becomes lower, it is preferable to make the upper limit of the moving distance L 600 mm.

The adjustment of the moving distance L can be performed by adjusting the position of the spinning nozzle and/or the nip roll. In this embodiment, the fusion bonding of the elastic filaments 13 and the nonwoven fabrics 11 and 12 is carried out by combining the molten elastic filaments 13 spun from the spinning nozzle 16 with the nonwoven fabrics being conveyed. The spun cloths 11, 12 merge and pass between a pair of nip rolls 18a, 18b. In the stretch sheet 10 of this embodiment, as described above, the elastic filaments 13 are bonded to the nonwoven fabrics 11 and 12 over their entire lengths. As the pinch rollers 18a and 18b, cylindrical rollers having no unevenness on the roller peripheral surface are used. the

Before the spun elastic filaments 13 merge with the first and second nonwoven fabrics 11 and 12, the elastic filaments 13 are stretched and their molecules are oriented in the stretching direction. And the diameter becomes smaller. By molecular orientation, elastic filaments 13 having a low elongation/recovery ratio of strength at 50% elongation can be obtained. From the viewpoint of fully stretching the elastic filaments 13 and preventing the elastic filaments 13 from breaking, it is also possible to blow wind (hot air, cold air) at a predetermined temperature to the spun elastic filaments 13 to adjust the elastic filaments 13. 13 temp. the

The stretching of the elastic filament 13 is not only stretching of the raw material resin in a molten state (melt stretching), but also stretching in a softened state during cooling thereof (softening stretching). The molten state refers to a state in which the resin can flow when an external force is applied. The melting temperature of the resin is measured as the peak temperature of Tan δ by viscoelasticity measurement (for example, measurement is performed by applying vibration deformation in the rotation direction to the resin sandwiched between circular parallel flat plates). In order not to cause filament breakage when the elastic resin is stretched, it is sufficient to ensure a long stretching range. From this viewpoint, the melting temperature of the elastic resin is preferably 130 to 300°C. In addition, from the viewpoint of heat resistance of the elastic resin, the melting temperature is preferably 220° C. or lower. In order to improve the fluidity of the resin to optimize the moldability, the molding temperature of the elastic filaments 13 (the temperature of the mold) is preferably +50° C. or higher than the melting temperature of the raw material resin, and the above-mentioned molding temperature is preferably at the temperature of the raw material resin due to heat resistance. Melting temperature below +110°C. The softening temperature is measured as the Tg temperature in the viscoelastic properties of the measurement sample of the sheet-like elastic resin. The range from softening temperature to melting temperature is called softening state. In addition, the state of temperature lower than softening temperature is called hardening state. The softening temperature is preferably 60°C or higher, more preferably 80°C to 180°C, from the viewpoint of crystal growth of the elastic resin during storage of the stretchable sheet 10 and reduction in the stretchability of the stretchable sheet 10 due to body temperature. the

The temperature of the elastic filaments 13 when joining the elastic filaments 13 and the nonwoven fabrics 11 and 12 is preferably 100° C. or higher, more preferably 120° C. or higher, and still more preferably 140° C. or higher for reliable fiber fusion bonding. In addition, the temperature of the elastic filaments is preferably 180° C. or lower from the viewpoint of maintaining the shape of the elastic filaments 13 to obtain the stretch sheet 10 with good stretch properties. More preferably, it is the range of 160 degreeC or less. The comprehensive result is that the most suitable filament temperature is in the range of 120-160°C, more preferably 140-160°C. The temperature at the time of bonding is to use a film composed of modified polyethylene, modified polypropylene, etc. having a melting point different from that of the elastic resin constituting the elastic filaments as a lamination base material to be bonded to the elastic filaments 13, and observe the bonding status to measure. At this time, if the elastic filaments are fusion-bonded with the laminated base material, the bonding temperature should be equal to or higher than the melting point of the laminated base material. the

When the elastic filaments 13 are bonded to the nonwoven fabrics 11 and 12, the elastic filaments 13 are substantially in an unstretched state (a state that does not shrink when the external force is removed). In the bonded state of the two, at least a part of the fibers constituting the nonwoven fabrics 11, 12 is preferably melt-bonded with the elastic filaments, or more preferably at least a part of the fibers constituting the nonwoven fabrics 11, 12 with the elastic filaments 13 Both of these undergo fusion bonding. Because in this way sufficient bonding strength can be obtained. The stretch properties of the resulting stretch sheet 10 are affected by the density of the joining points between the elastic filaments 13 and the nonwoven fabrics 11 and 12 . In addition, the expansion and contraction characteristics can be adjusted by joining temperature, joining pressure, and shifting of joining points due to elastic expressing treatment of the nonwoven fabrics 11 and 12 described later. By fusion-bonding the constituent fibers of the nonwoven fabrics 11 and 12 to the elastic filaments 13, the joint strength at each joint is improved. If the density of joint points is reduced, the resistance to expansion and contraction by the nonwoven fabrics 11 and 12 is reduced, and the stretchable sheet 10 having sufficient joint strength can be obtained, which is preferable. the

When the elastic filaments 13 are merged with the first and second nonwoven fabrics 11 and 12, the elastic filaments 13 are arranged in one direction without intersecting each other. Then, in the state where the elastic filament 13 is merged with the first and second nonwoven fabrics 11, 12 and the elastic filament 13 is clamped between the two nonwoven fabrics 11, 12, a pair of nip rollers 18, 18 Clamp the three. The conditions of crimping will affect the hand feeling of the stretchable sheet 10 obtained. If the clamping force is too high, the elastic filaments 13 are likely to sink into the two non-woven fabrics 11 and 12, thereby easily reducing the hand feeling of the stretchable sheet 10 obtained. From this point of view, the nip force generated by the nip rollers 18, 18 is sufficient to bring the elastic filaments 13 into contact with both nonwoven fabrics 11, 12, and it is not necessary to apply an excessively high nip force. the

In the state where the elastic filament 13 is merged with the first and second nonwoven fabrics 11 and 12 and the elastic filament 13 is sandwiched between the two nonwoven fabrics 11 and 12, a pair of kneading rollers 18 and 18 are used to Another preferred method of nip-pressing the three includes a method of merging the elastic filament 13 and the nonwoven fabrics 11, 12, and providing a space W between the pair of nip rolls 18a, 18b (see FIG. 6). In the same manner as above, the interval W provided between 18a and 18b is preferably 0.05 to 1 mm, particularly preferably 0.05 to 0.5 mm, from the viewpoint of obtaining sufficient joint strength without damaging the elastic filaments. the

(G/ρvnπ)求得。其中，G为整个机械宽度上的每单位时间的挤出量(g/min)、n为整个机械宽度上的长丝根数、v为夹持辊速度(m/min)、ρ为长丝树脂的密度(g/cm³)。通过使W/T0在上述范围内，弹性长丝与无纺布构成纤维的接合点密度和无纺布构成纤维在弹性长丝中的陷入之间获得平衡，由此可以兼顾上述的弹性长丝与无纺布之间的接合强度和单位伸缩片材的构成树脂单位面积重量的25％回复强度。  When the total value of the thickness of each of the nonwoven fabrics 11 and 12 before joining and the thickness of the elastic filament 13 immediately before joining (clamping) (thickness along the thickness direction of the nonwoven fabric) is T0, the above-mentioned pair The ratio W/T0 of the interval W between the nip rolls 18a and 18b to T0 is preferably 0.05 to 0.8, particularly preferably 0.1 to 0.4. The thickness of the nonwoven fabric can be obtained by the aforementioned method. The thickness of the elastic filament (mm) is

(G/ρvnπ) obtained. Among them, G is the extrusion amount per unit time on the entire machine width (g/min), n is the number of filaments on the entire machine width, v is the nip roller speed (m/min), and ρ is the filament Density of the resin (g/cm ³ ). By setting W/T0 within the above-mentioned range, a balance can be achieved between the joining point density of the elastic filament and the nonwoven fabric constituting fiber and the entrapment of the nonwoven fabric constituting fiber in the elastic filament, thereby achieving the above-mentioned elastic filament. Bonding strength with non-woven fabric and 25% recovery strength per unit area weight of constituting resin per stretch sheet.

The temperature of the nip roll 18 is mentioned as another condition of the nip by the nip roll 18. The results of the research of the present inventors are: instead of nip-pressing in the state of heating the nip rollers 18, it is better not to heat (i.e. let it be) or to nip-press while cooling to obtain a stretchable sheet 10 with a good feel. . When cooling the nip roll 18, it is preferable to use a cooling medium such as cooling water, and adjust the set temperature of the surface of the nip roll 18 to 10 to 50°C. the

In this way, a composite 19 in which the elastic filaments 13 are sandwiched between the two nonwoven fabrics 11 and 12 is obtained. When a nonwoven fabric originally having stretchability is used as the nonwoven fabrics 11 and 12, the composite 19 is the stretchable sheet 10 itself. On the other hand, when using a non-woven fabric that does not originally have elongation as the non-woven fabric 11, 12, the composite 19 including the non-woven fabric 11, 12 performs elastic expression along the extending direction of the elastic filament 13. processing, so as to make the complex 19 stretchable. In this manufacturing method, this operation is carried out as follows: Using an elastic performance processing device 22 provided with a pair of toothed rollers 20 and 21 respectively formed with teeth and tooth grooves alternately in the circumferential direction, the composite body 19 is moved along its conveying direction. That is, the elastic expressing treatment is performed along the extending direction of the elastic filaments 13 . the

The elastic performance processing device 22 has a known elevating mechanism (not shown) for vertically displacing the pivot portions of one or both toothed rollers 20, 21, so the interval between the toothed rollers 20, 21 can be adjusted. In this manufacturing method, the combination of each toothed roller 20, 21 is that the teeth of one toothed roller 20 are inserted between the teeth of the other toothed roller 21, and the teeth of the other toothed roller 21 are inserted in one toothed space. Between the teeth of the roller 20, the composite body 19 is inserted between the two toothed rollers 20 and 21 in this state, and then elastic expressing treatment is performed on it. the

In the elastic performance processing device 22, both of a pair of toothed rollers 20 and 21 may be driven by a driving source (co-rotating rollers), or only one toothed roller 20 or 21 may be driven by a driving source (following rollers). ), in this manufacturing method, only the cogged roller 21 of the lower side is driven by the driving source, and the cogged roller 20 of the upper side is not connected with the driving source, but follows the rotation of the cogged roller 21 (with the rotation ). The use of the follow-up roller makes it easy to make the striped pattern of the high unit area weight part 14 and the low unit area weight part 15 clearly appear on the elastic sheet material 10 processed by the elastic expression treatment, thereby improving the pattern design of the elastic sheet material 10, and From the viewpoint of making the basis weight lower than the low basis weight portion 15 to improve air permeability, use of a follower roll is preferable. As the tooth profile of the toothed rollers 20 and 21 , it is preferable to use a general involute tooth profile and a cycloid tooth profile, and it is particularly preferable to use a tooth profile in which the width of these teeth is narrowed. the

FIG. 7 schematically shows the state of the elastic expression treatment of the composite body 19 . When the composite 19 passes between the toothed rollers 20 and 21 , the composite 19 is hardly stretched in the region (between P3 and P2 and between P1 and P4 ) in contact with the teeth 23 and 24 of the toothed rollers 20 and 21 . On the other hand, through the tooth surface of the tooth 24 of the cogged roller 21 as the driving roller, the region (between P2 and P1) that is pressed toward the tooth surface of the tooth 23 of the cogged roller 20 as the follower roller is pressed. The two teeth 20, 21 are greatly stretched. In addition, in the region (between P4-P3) pulled away from the teeth 23 of the tooth-groove roller 20 by the tip end portions of the teeth 24 of the tooth-groove roller 21, although the area (between P2-P1) does not reach the extent of the above-mentioned region (between P2-P1), the Also stretched greatly. the

In addition, the composite body 19 is basically not stretched as described above in the region (between P3-P2 and P1-P4) in contact with the top ends of the teeth 23, 24 of the toothed rollers 20, 21, but is stretched by the teeth 23. , 24 is partially compressed in its diameter direction, that is, in the thickness direction of the composite body 19, and thus becomes thinner in the thickness direction. However, since the directions in which the area (between P3-P2) and the area (between P1-P4) are locally squeezed are in opposite directions, the thinning directions are also in opposite directions. the

Through the above stretching process, the elastic filament 13 can be prevented from peeling off between the two nonwoven fabrics 11, 12, and the two nonwoven fabrics 11, 12 in the composite body 19 can be effectively stretched, so that the composite body 19 can be made It is scalable. In addition, the greatly stretched region (between P2-P1 and P4-P3) becomes the low basis weight portion 15, and the substantially unstretched region (between P3-P2, P1-P4) becomes the high basis weight portion. Part 14. the

In particular, when the non-woven fabrics 11 and 12 contain low-stretch fibers, the fibers are stretched and thinned between the above-mentioned (P2-P1) and (P4-P3), thereby causing a change in fiber thickness. Periodically changing unsizing fibers. the

The stretching force generated by the toothed rollers 20, 21 mainly acts on the stretching of the low-stretching fibers, and does not apply excessive force to the junction between the nonwoven fabrics 11, 12 and the elastic filaments 13. As a result, it is possible to prevent the breakage of the joined portion, to prevent the nonwoven fabrics 11, 12 from peeling off from the elastic filaments 13, and to stretch the composite 19 efficiently. In addition, by this stretching, as shown in FIG. 8, the non-woven fabrics 11, 12 are sufficiently elongated without breaking the bond between the fibers, whereby the non-woven fabrics 11, 12 prevent the elastic filaments 13 from being free. The degree of stretching is greatly reduced. As a result, according to the present manufacturing method, the stretchable sheet 10 having high strength, high stretchability, and good appearance with less damage and fuzz can be efficiently manufactured. In addition, in Fig. 8, for convenience, the thickness of the inelastic fibers produced by stretching is shown as the same. the

As mentioned above, when the non-woven fabrics 11, 12 contain low-stretch fibers, since the fibers can be smoothly processed for elastic expression, and the bonding between these fibers will not be damaged by stretching, the elastic expression treatment The resulting reduction in the strength of the nonwoven fabrics 11, 12 can be controlled as much as possible. Specifically, the ratio of the tensile strength of the stretch sheet 10 obtained after stretching to the tensile strength of the composite 19 before the elastic expressing treatment is 0.3 to 0.99, particularly 0.5 to 0.99, and further 0.7 to 0.99. A value close to 1. The tensile strength referred to here can be measured according to the following method of measuring the maximum strength. the

<Determination of maximum strength>

The stretchable sheet 10 is cut out to a rectangular test piece having a size of 200 mm in the stretching direction and 50 mm in a direction perpendicular to the stretching direction. Set the distance between chucks to 150mm. The test piece was stretched at a rate of 300 mm/min in the stretching direction of the stretchable sheet 10, and the load at that time was measured. Let the load at the maximum point at this time be the maximum intensity. The maximum strength was also measured for the composite 19 before the elasticity expressing treatment by the same method. The above-mentioned maximum strength is preferably measured using a tensile tester AG-1kNIS manufactured by Shimadzu Corporation under the conditions of a measurement environment temperature of 22°C and a humidity of 65%RH. the

The composite 19 is subjected to an elastic expressing process by a pair of toothed rollers 20 and 21 , whereby the target stretch sheet 10 is obtained. After the obtained stretchable sheet 10 passes through the toothed rollers 20 and 21, the stretched state in the MD direction is quickly released due to its own shrinkage recovery force. As a result, the length of the stretch sheet 10 in the conveyance direction is substantially recovered. Thus, in the stretched state, the high basis weight portions 14 and the low basis weight portions 15 are alternately arranged along the extending direction of the elastic filament 13 . In addition, when the stretched state is released, the stretched state may be completely released, or the stretched state may be released while maintaining a certain degree of stretched state within the limit of expressing stretchability. the

The thickness of the elastic sheet 10 is preferably increased by 1.1 to 4 times, particularly preferably 1.3 to 3 times the thickness of the composite 19 before the elasticity expressing process by the above elastic expressing process. As a result, the fibers constituting the nonwoven fabrics 11 and 12 are plastically denatured and elongated, whereby the fibers become thinner. At the same time, both nonwoven fabrics 11 and 12 become bulkier, feel better on the skin, and have better elasticity (cushioning properties). the

From the viewpoint of exhibiting sufficient stretch properties, the load A (hereinafter also referred to as 50%) when the thus obtained stretch sheet 10 is stretched by 100% in the direction in which the elastic filaments 13 extend and returns to 50% from this state recovery strength), and the ratio (A/B) of the load B (hereinafter also referred to as 50% elongation strength) when elongated by 50% along the extending direction of the elastic filament 13 is preferably 50% or more, particularly preferably 65%. above. the

In addition, although it varies depending on specific uses, the entire basis weight of the stretch sheet 10 is preferably 10 to 150 g/m ² , particularly preferably 25 to 60 g/m ² . The thickness of the stretch sheet 10 is preferably 0.05 to 5 mm, particularly preferably 0.5 to 2 mm. The thickness of the stretch sheet 10 can be measured by the method similar to the measurement of the thickness of each nonwoven fabric 11 and 12 mentioned above.

The stretch sheet 10 of the present embodiment is preferably used as an outer wrapping material for a pants-type disposable diaper. In this case, the stretchable sheet 10 of this embodiment may be used as the outer sheet and a non-stretchable sheet as the inner sheet, and the two sheets may be bonded together to be used as the above-mentioned outer packaging material. In addition to this application, it can also be used in various applications such as medical disposable clothes, cleaning sheets, eye masks, facial masks, and bandages by taking advantage of its good texture, anti-pilling properties, stretchability, and air permeability. . It is particularly preferably used as a constituent material of absorbent articles such as sanitary napkins and disposable diapers. Examples of such constituent materials include liquid-permeable sheets (including front sheets, sub-layers, etc.) on the skin side of the absorber, sheets constituting the outer surface of disposable diapers, sheets for making the waist Sheets with elastic stretchability such as the waist or around the legs. Moreover, it can be used as a sheet|seat etc. which form the wing of a sanitary napkin. In addition, it can also be used in a site other than these but where stretchability is desired. The weight per unit area or thickness of the stretchable sheet 10 can be properly adjusted according to its specific application. For example, when used as a constituent material of an absorbent article, the basis weight is preferably about 20 to 60 g/m ² , and the thickness is preferably about 0.5 to 1.5 mm.

As mentioned above, although this invention was demonstrated based on preferable embodiment, this invention is not limited to the said embodiment. For example, in the expansion and contraction of the above-mentioned embodiment, a large number of elastic filaments 13 are sandwiched between two nonwoven fabrics 11 and 12, but instead, a large number of elastic filaments may be bonded to the surface of one nonwoven fabric. To make a stretch sheet. In this case, a resin having low adhesiveness when cured can be used as the constituent material of the elastic filaments, which is preferable from the viewpoint of preventing stagnation when the stretch sheet 10 is stored in a rolled state. the

In addition, in the above embodiment, the elastic filaments 13 all have the same diameter and are arranged at equal intervals, so the elongation stress is the same for any part of the stretch sheet 10 . However, instead, the stretchable sheet may be configured so as to be composed of two or more regions having different elongation stresses in the elongation direction of the elastic filaments. Two or more of the regions are arranged substantially side by side in the elongation direction. In this case, the pitch of the adjacent elastic filaments differs and/or the diameter of the elastic filaments differs between regions having different elongation stresses. This makes it possible to vary the elongation stress between the regions. When manufacturing a stretch sheet, two or more different resins can also be introduced into any spinning nozzle for spinning, so that the elongation stress of each region is different. the

The stretch sheet 10 may be partially embossed, or the elastic filaments 13 may be partially cut or partially heat-sealed. These operations are performed to form non-stretchable portions of the stretchable sheet 10 or to locally increase the strength. Or, it is performed in order to bond with other components, or to provide design. the

In addition, the stretching direction may be not only the moving direction of the nonwoven fabrics 11 and 12 but may be oblique, for example, in the elastic expressing treatment performed after bonding the elastic filaments 13 to the nonwoven fabrics 11 and 12 . Furthermore, two or more elastic expression processing methods may be combined, or the stretch ratio may be increased stepwise, or the elastic expression processing may be partially performed. The elastic performance processing direction can be not only one direction, but also two vertical directions. The stretchable sheet may be stretchable in all directions by joining a nonwoven fabric stretchable in one direction and a nonwoven fabric stretchable in a direction perpendicular thereto. the

In addition, in the manufacturing method of the above-mentioned embodiment, the elasticity expressing processing apparatus provided with a pair of tooth-groove rolls 20 and 21 is used for the elastic expressing processing of the composite body 19, However, instead, the elastic expressing processing apparatus provided with the tenter can also be used. The expression processing device is used for elastic expression processing. the

In addition, in the above-mentioned production method, as another method of joining the elastic filaments 13 and the nonwoven fabrics 11 and 12, the elastic filaments 13 may be directly extruded on one nonwoven fabric without melt stretching. The draw ratio at this time was 1 time. In addition, before joining the elastic filaments 13 to the nonwoven fabrics 11 and 12, an adhesive may be applied auxiliary on the nonwoven fabric or the elastic filaments, and then the elastic filaments may be in a substantially unstretched state. Next fit. In addition, it is also possible not to apply an adhesive, but to perform auxiliary heat treatment (hot air blowing by hot air method, steam injection, heat embossing), mechanical Interweaving (acupuncture method, spunlace method), etc. In this case, instead of the nonwoven fabric, a fiber web may be used on one or both sides. the

Example

Hereinafter, the present invention will be described in further detail through examples. However, the scope of the present invention is not limited to these Examples. the

[Example 1-1]

Stretchable nonwoven fabrics having the structures shown in FIGS. 1 and 2 were manufactured using the apparatus shown in FIG. 5 . As the first and second nonwoven fabrics 11 and 12, an air-through nonwoven fabric with a basis weight of 15 g/m ² was used. The constituent fibers of this nonwoven fabric are core-sheath composite fibers (core: PET; sheath: PE) having a diameter of 19 µm, a maximum elongation of 180%, and a fiber length of 44 mm. As the raw material resin of the elastic filament 13, an elastomer composed of SEPS resin (weight-average molecular weight: 50,000, MFR: 60 g/10 min (230° C., 2.16 kg)) (JIS K7210: 1999) was used. The spinning conditions were: the temperature of the spinning head 17 was 310° C., the diameter of the spinning nozzles 16 was 400 μm, and the pitch of the spinning nozzles 16 was 1 mm. The elastic filaments 13 have a diameter of 120 μm. The apparent weight per unit area of the filament (weight of the filament in the sample/area of the sampled sheet) was 10 g/m ² , and the draw ratio was 11 times. The draw ratio is defined by (nozzle diameter/fiber diameter before stretching expression processing) ² . The elastic expression processing of the composite body 19 was performed using an elastic expression processing apparatus 22 including a pair of toothed rollers 20 and 21 alternately formed with teeth and grooves in the axial direction. The pitch between the teeth and the pitch between the teeth was 2.0 mm (the pitch P between the teeth in the meshing state was 1.0 mm). The pressing amount of the upper and lower toothed rollers was adjusted, and the composite 19 was subjected to elastic expressing treatment in the extending direction of the elastic filament 13 at a draw ratio of 3.0 times. Thus, a stretchable sheet 10 with a weight per unit area of 40 g/m ² stretchable along the extending direction of the elastic filaments 13 was obtained. The obtained stretchable sheet 10 presents a striped pattern produced by the elastic filaments 13 through the non-woven fabric. In addition, the striped pattern produced by the high basis weight region and the low basis weight region was also exhibited. With these two striped patterns, the stretch sheet also presents a checkered pattern. In addition, the elastic filaments 13 in the stretch sheet 10 have an elliptical cross-section whose long axis is in the plane direction of the sheet 10, and the ratio of the long axis/short axis is 1.6. The width when stretched 1.5 times is the original width 96% of the width is reduced to 4%. It was confirmed with a microscope that the thickness of the constituent fibers of the nonwoven fabrics 11 and 12 in the stretch sheet 10 is different along the length direction of the fibers. The constituent fibers had a maximum fiber diameter of 26.1 μm, a minimum fiber diameter of 6.8 μm, and a fiber diameter ratio of 3.8. In addition, the thickness of the fiber diameter changes periodically within this range.

[Example 1-2]

The pitch of the spinning nozzles 16 was set to 1 mm in the width direction of the spinning head 17 to form a first row of nozzles. Then, starting from the first nozzle row, a second nozzle row was formed at a position separated by 1 mm in the moving direction of the spinning head 17 at the same pitch as the first nozzle row. The first nozzle row and the second nozzle row are arranged with a half pitch shifted from each other. In addition, except that the stretch ratio of the elastic filament 13 was changed to 25 times, and the diameter of the elastic filament 13 was 80 μm, the stretch sheet 10 was obtained in the same manner as in Example 1-1. In the stretchable sheet 10, the distance between the elastic filaments 13 is 0.5 mm. the

[Example 1-3]

Forming the first region, wherein the nozzle diameter of the spinning nozzle 16 is set to 400 μm, the draw ratio of the elastic filament 13 is set to 11 times, and the diameter of the elastic filament 13 is set to 120 μm; and forming the second region A region in which the nozzle diameter of the spinning nozzle 16 was set to 300 μm, the draw ratio of the elastic filament 13 was set to 18 times, and the diameter of the elastic filament 13 was set to 70 μm. Except for this, it carried out similarly to Example 1-1, and obtained the stretch sheet 10. The first region and the second region are aligned in the width direction of the stretch sheet 10 . The diameters of two types of elastic filaments having different thicknesses in the stretchable sheet were measured respectively. the

[Example 1-4]

In the styrene-based elastomer used in Example 1-1, 1.5% by weight of purple coloring masterbatch compounding material (PE-based resin matrix, product with a pigment concentration of 60% by weight) was dry-blended, except that purple elastic long Except for the yarn 13, the stretchable sheet 10 was obtained in the same manner as in Example 1-1. In this stretch sheet, the stripe pattern produced by the elastic filaments 13 is more obvious through the non-woven fabric. the

[Example 1-5]

The composite 19 used in Example 1-2 was heat-treated by hot air blowing using the hot air method, and then stretched under the same conditions as in Example 2 to obtain a stretch sheet 10 . In this stretch sheet, the fibers of the nonwoven fabrics 11 and 12 are melt-bonded to each other, and the joint strength is further improved. the

[Comparative example 1-1]

A stretch sheet was produced according to the method described in Patent Document 1. That is, a stretchable fiber web (basis weight: 73 g/m ² ) of CONWED was used, and as the first and second nonwoven fabrics 11 and 12, air-through nonwoven fabrics with a basis weight of 20 g/m ² were used. The constituent fibers of this nonwoven fabric are core-sheath composite fibers (core PET; sheath: PE) having a diameter of 17 μm, a maximum elongation of 30%, and a fiber length of 44 mm. With respect to the MD direction of the nonwoven fabrics 11 and 12, the lattice of the stretchable fiber web is approximately square (3.2 mm in both the MD direction and the CD direction). The above-mentioned fiber web and nonwoven fabric were subjected to heat/pressure bonding at a pressure of about 10 kg/cm ² for 10 seconds using metal presses heated to about 120° C. and about 60° C., respectively. The resulting sheet was stretched using a stretching device (elasticity expression processing device) having a pair of concave-convex rolls (the pitch P between the teeth in the meshing state is 1.0 mm) in which large-diameter portions and small-diameter portions are alternately formed in the axial length direction. Flexible performance handling. Since the constituent fibers of the nonwoven fabric do not elongate, if the stretching ratio of the elastic expressing treatment is high, the phenomenon of opening holes in the nonwoven fabric will be observed. Therefore, the treatment was performed under the condition that the draw ratio in the MD direction was 2.7 times. The degree of stretching is controlled by adjusting the pressing amount of the upper and lower concave-convex rollers. Since the obtained stretch sheet is difficult to stretch, the reduction in width becomes large. In addition, the rigidity of the elastic fiber web was felt, and the texture was poor.

[Comparative example 1-2]

A stretchable sheet was obtained using a stretchable fiber web (weight per unit area: 55 g/m ² ) of CONWED in the same manner as in Comparative Example 1-1. With respect to the MD direction of the nonwoven fabrics 11 and 12, the lattice of the stretchable fiber web is approximately rhombus (9.5 mm in both the MD direction and the CD direction). The above-mentioned fiber web and nonwoven fabric were subjected to heat/pressure bonding at a pressure of about 10 kg/cm ² for 10 seconds using metal presses heated to about 120° C. and about 60° C., respectively. The resulting sheet was stretched using a stretching device (elasticity expression processing device) having a pair of concave-convex rollers (the pitch P between the teeth in the meshing state is 1.0 mm) having large diameter portions and small diameter portions alternately formed in the axial length direction, Stretched 3.0 times in the MD direction for elastic expressive processing. In the resulting stretch sheet, since the fibers of the nonwoven fabric were not stretched, many holes were opened in the nonwoven fabric during the elastic expressing treatment. Therefore, although the sheet has thickness as a whole, the joining point between the elastic fiber web and the nonwoven fabric is relatively hard. The result is inferior in feel.

[evaluate]

For the stretch sheets obtained in Examples and Comparative Examples, 50% recovery strength/50% elongation strength and hand feeling were measured and evaluated by the following methods. In addition, the thicknesses of the stretchable sheet and the nonwoven fabric were measured by the method described above. These results are shown in Table 1 below. the

[50% recovery strength/50% elongation strength] 

A test piece was cut out from the stretchable sheet to a size of 200 mm in the stretching direction and 50 mm in the direction perpendicular to the stretching direction. The test piece was installed and fixed on a tensile testing machine AG-1kNIS manufactured by Shimadzu Corporation so that the distance between chucks was 150 mm. The test piece was stretched at a rate of 300 mm/min in the stretching direction. The load was recorded at 50% elongation, and this value was taken as the 50% elongation strength. The test piece was further stretched to 100%, and then shrunk at the same speed in the recovery direction (shrinking direction) to form a 50% stretched state. Record the load at this time as 50% recovery strength. The above measurements are carried out in an environment with a temperature of 20±2° C. and a humidity of 65±5% RH. the

[feel]

Ten female evaluators evaluated the texture of the stretchable sheet in an environment with a temperature of 25° C. and a humidity of 40% in a dark box where the stretchable sheet could not be seen. Based on the evaluation by each evaluator, the following points were used for scoring, and the average score (rounded up to one decimal point) of 10 evaluators was used as the evaluation score of texture. the

5 points: Feel good. the

4 points: Feeling is slightly better. the

3 points: average. the

2 points: Feeling slightly poor. the

1 point: The hand feeling is bad. the

From the results shown in Table 1, it can be seen that the stretchable sheets of the respective examples have better stretch properties than the stretchable sheets of the comparative examples. Moreover, it turns out that it has thickness and has favorable texture. In addition, in the stretch sheet of each example, the elastic filaments are arranged separately so that they do not substantially intersect each other and do not contact each other. On the other hand, the elastic body of the stretch sheet of Comparative Example 1-1 was destroyed by pressing, the fiber web became conspicuous, and the gloss of the fiber web was present, so it could not be said that the appearance was good. the

[Example 2-1～2-5 and Comparative Example 2-1～2-3]

A composite 19 (precursor of the stretch sheet 10 shown in FIGS. 1 and 2 ) was obtained using the apparatus shown in FIG. 5 , and this was used as a sample of Example 2-1. That is, a device having a structure in which a spinning head 17 is installed on a single-screw extruder, and the spinning head 17 is provided with spinning nozzles 16, and 250 spinning nozzles 16 are arranged on a straight line at intervals of 1 mm. The nozzle hole is a cylindrical hole with an inner diameter of 0.45 mm and a length of 4.5 mm. The following triblock copolymers (1) to (8) as the resin composition are melted at a melting temperature of 290 ℃, the ejection amount is 0.3kg/min and is ejected from the spinning nozzle 16 to obtain the long filament as the precursor of the elastic filament 13, which is used at a position 100 mm away from the spinning nozzle 16 downwards. Air-through non-woven fabrics 11, 12 are clamped and they are joined, thereby obtaining a composite 19 in which elastic filaments 13 are clamped between non-woven fabrics 11 and non-woven fabrics 12, wherein said air-through non-woven fabrics 11, 12 is a nonwoven fabric having a weight per unit area of 20 g/m ² , a thickness of 0.4 mm, and a fiber diameter of 3 dtex sent out at a speed of 150 m/min. In addition, both the nonwoven fabrics 11 and 12 are nonwoven fabrics that do not have extensibility originally.

In the following 8 kinds of A1-B-A2 type triblock copolymers (1)～(8), triblock copolymers (1)～(5) are compounds within the scope of the present invention, triblock copolymers (6) to (8) are compounds outside the scope of the present invention. the

A1-B-A2 type triblock copolymer ( 1 ):

A1'-B'-A2' type triblock copolymer (SEPS triblock copolymer, styrene content is 30% by weight, ethylene-propylene content is 70% by weight, the weight average molecular weight of A1', A2' is 7500, the weight average molecular weight of B is 35000) 80% by weight, and A1 "-B"-A2 " type triblock copolymer (SEPS triblock copolymer, styrene content is 18% by weight, ethylene-propylene content is 82% by weight, the weight average molecular weight of A1", A2" is 8100, and the weight average molecular weight of B" is 73800) 20% by weight is mixed with a Henschel mixer, and the obtained polymer is used as a triblock copolymer (1) . The maximum value of the above-mentioned melt tension of the triblock copolymer (1) (in the state of heating and melting at a temperature of 245°C, measured at 8.4 m from a cylindrical nozzle hole with an inner diameter of 0.45 mm and a length of 4.5 mm The maximum value of the melt tension at the time of ejection at the ejection speed/minute) was 0.07 cN. the

The weight-average molecular weight of the polymer block A1 in the triblock copolymer (1) is: [(the weight-average molecular weight of the polymer block A1') × (the A1'-B'-A2' contained in the resin composition The percentage content in the total amount of two or more A1-B-A2 type triblock copolymers)+(the weight-average molecular weight of the polymer block A1″)×(the A1″-B″-A2 "The percentage content in the total amount of two or more A1-B-A2 type triblock copolymers contained in the resin composition) =] 7620. the

The weight-average molecular weight of polymer block B in the three-block copolymer (1) is: [(the weight-average molecular weight of polymer block B') * (the A1 '-B'-A2 ' contained in the resin composition The percentage of the total amount of two or more A1-B-A2 type triblock copolymers)+(the weight-average molecular weight of the polymer block B ")×(the A1"-B"-A2 "The percentage content in the total amount of two or more A1-B-A2 type triblock copolymers contained in the resin composition) =] 42760. the

The weight-average molecular weight of the polymer block A2 in the triblock copolymer (1) is: [(the weight-average molecular weight of the polymer block A2') × (the A1'-B'-A2' contained in the resin composition The percentage content in the total amount of two or more A1-B-A2 type triblock copolymers)+(the weight-average molecular weight of the polymer block A2")×(the A1"-B"-A2 "The percentage content in the total amount of two or more A1-B-A2 type triblock copolymers contained in the resin composition) =] 7620. the

A1-B-A2 type triblock copolymer (2):

A1-B-A2 type triblock copolymer (SEPS triblock copolymer, styrene content is 18% by weight, ethylene-propylene content is 82% by weight, the weight average molecular weight of A1, A2 is 8100, the weight of B The average molecular weight is 73800) and 100% by weight was used as the triblock copolymer (2). The above-mentioned maximum value of the melt tension of the triblock copolymer (2) was 0.13 cN. the

A1-B-A2 type triblock copolymer ( 3 ):

A1-B-A2 type triblock copolymer (SEBS triblock copolymer, styrene content is 20% by weight, ethylene-butylene content is 80% by weight, and the weight average molecular weight of A1, A2 is 9400 , The weight average molecular weight of B is 75200) 100% by weight is used as a triblock copolymer (3). The maximum value of the aforementioned melt tension of the triblock copolymer (3) was 0.15 cN.

A1-B-A2 type triblock copolymer ( 4 ):

A1'-B'-A2' type triblock copolymer (SEPS triblock copolymer, styrene content is 30% by weight , ethylene-propylene content is 70% by weight, the weight of A1', A2' The average molecular weight is 7500, the weight average molecular weight of B' is 35000) 60% by weight, and A1 "-B"-A2" type triblock copolymer (SEPS triblock copolymer, styrene content is 18% by weight, ethylene -The propylene content is 82% by weight, the weight average molecular weight of A1", A2" is 8100, and the weight average molecular weight of B" is 73800) 40% by weight is mixed with a Henschel mixer, and the obtained polymer is used as a triblock copolymer (4) use. The maximum value of the melt tension of the triblock copolymer (4) was 0.20 cN.

The weight-average molecular weight of the polymer block A1 in the triblock copolymer (4) is: [(the weight-average molecular weight of the polymer block A1') × (the A1'-B'-A2' contained in the resin composition The percentage content in the total amount of two or more A1-B-A2 type triblock copolymers)+(the weight-average molecular weight of the polymer block A1″)×(the A1″-B″-A2 "The percentage content in the total amount of two or more A1-B-A2 type triblock copolymers contained in the resin composition) =] 7740. the

The weight-average molecular weight of polymer block B in the three-block copolymer (4) is: [(the weight-average molecular weight of polymer block B') * (the A1 '-B'-A2 ' contained in the resin composition The percentage of the total amount of two or more A1-B-A2 type triblock copolymers)+(the weight-average molecular weight of the polymer block B ")×(the A1"-B"-A2 "The percentage content in the total amount of two or more A1-B-A2 type triblock copolymers contained in the resin composition) =] 50520. the

The weight-average molecular weight of the polymer block A2 in the triblock copolymer (4) is: [(the weight-average molecular weight of the polymer block A2') × (the A1'-B'-A2' contained in the resin composition The content in the total amount of two or more A1-B-A2 type triblock copolymers)+(the weight average molecular weight of the polymer block A2 ") × (the A1 "-B"-A2 "in The percentage content of the total amount of two or more A1-B-A2 type triblock copolymers contained in the resin composition =] 7740. the

A1-B-A2 type triblock copolymer ( 5 ):

A1'-B'-A2' triblock type copolymer (SEPS triblock copolymer, styrene content is 30% by weight, ethylene-propylene content is 70% by weight, the weight average molecular weight of A1', A2' is 7500, the weight average molecular weight of B' is 35000) 50% by weight, and A1 "-B"-A2" type triblock copolymer (SEPS triblock copolymer, styrene content is 30% by weight, ethylene-propylene content 70% by weight, the weight average molecular weight of A1", A2" is 10500, and the weight average molecular weight of B" is 49000) 50% by weight is mixed with a Henschel mixer, and the resulting polymer is used as a triblock copolymer (5) use. The maximum value of the melt tension of the triblock copolymer (5) was 0.07 cN. the

The weight-average molecular weight of the polymer block A1 in the triblock copolymer (5) is: [(the weight-average molecular weight of the polymer block A1') × (the A1'-B'-A2' contained in the resin composition The percentage content in the total amount of two or more A1-B-A2 type triblock copolymers)+(the weight-average molecular weight of the polymer block A1″)×(the A1″-B″-A2 "The percentage content in the total amount of two or more A1-B-A2 type triblock copolymers contained in the resin composition) =] 9000. the

The weight-average molecular weight of polymer block B in the three-block copolymer (5) is: [(the weight-average molecular weight of polymer block B') * (the A1 '-B'-A2 ' contained in the resin composition The percentage of the total amount of two or more A1-B-A2 type triblock copolymers)+(the weight-average molecular weight of the polymer block B ")×(the A1"-B"-A2 "The percentage content in the total amount of two or more A1-B-A2 type triblock copolymers contained in the resin composition) =] 42000. the

The weight-average molecular weight of the polymer block A2 in the triblock copolymer (5) is: [(the weight-average molecular weight of the polymer block A2') × (the A1'-B'-A2' contained in the resin composition The percentage content in the total amount of two or more A1-B-A2 type triblock copolymers)+(the weight-average molecular weight of the polymer block A2")×(the A1"-B"-A2 "The percentage content in the total amount of two or more A1-B-A2 type triblock copolymers contained in the resin composition) =] 9000. the

A1-B-A2 type triblock copolymer ( 6 ):

By A1-B-A2 type triblock copolymer (SEPS triblock copolymer, styrene content is 30% by weight, ethylene-propylene content is 70% by weight, the weight average molecular weight of A1, A2 is 10500, The weight average molecular weight of B is 49000) 100% by weight was used as a triblock copolymer (6). The above-mentioned maximum value of the melt tension of the triblock copolymer (6) was 0.08 cN.

A1-B-A2 type triblock copolymer ( 7 ):

A1-B-A2 type triblock copolymer (SEBS triblock copolymer, styrene content is 20% by weight, ethylene-butylene content is 80% by weight, and the weight average molecular weight of A1, A2 is 4750 , The weight average molecular weight of B is 38000) 100% by weight is used as a triblock copolymer (7). The maximum value of the aforementioned melt tension of the triblock copolymer (7) was 0.05 cN.

A1-B-A2 type triblock copolymer ( 8 ):

By A1-B-A2 type triblock copolymer (SEPS triblock copolymer, styrene content is 30% by weight, ethylene content is 70% by weight, the weight average molecular weight of A1 , A2 is 22750, B's The weight average molecular weight was 84500) and 100% by weight was used as the triblock copolymer (8). Melt tension was measured as shown in Fig. 4, but it could not be measured because the viscosity was high and it could not be extruded.

[evaluate]

The properties of the composite 19 (elastic filament 13 ) obtained in Examples and Comparative Examples are shown in Table 2 and Table 3 below together with the composition of the resin composition (material for forming the elastic filament 13 ). The measurement method of each item in Table 2 and Table 3 is as follows. the

<Spinning Formability of Elastic Filament>

In the state where the resin composition (the above-mentioned triblock copolymers (1) to (8)) serving as the forming material of the elastic filament was heated and melted at a temperature of 245° C., the In the cylindrical nozzle hole, it is sprayed as shown in FIG. 4 at a spray speed of 8.4 m/min to make a long filament, and the long filament is collected on a stainless steel plate arranged at a position 100 mm downward from the nozzle hole. . The case where the collected filaments are continuous without breaking and the sides of the filaments are smooth when observed with a microscope at 200 times magnification is evaluated as ○ (spinning formability is good), and the cases where the filaments are broken and discontinuous or long The case where the thickness of the yarn became non-uniform due to die swell was evaluated as x. the

<bending state>

From the composites obtained in Examples and Comparative Examples, 30 cm was sampled along the mechanical movement direction (MD direction, the moving direction of the composite during composite manufacture), and the elastic length was visually observed through the nonwoven fabric covering the elastic filaments. The tortuosity of the wire. Among 100 adjacent elastic filaments, the case where less than 10 intersected or contacted the elastic filaments was evaluated as ○, and the case where 11 or more intersected or contacted among them was evaluated as x. the

<Diaper deflection and drop resistance>

The composites obtained in Examples and Comparative Examples were stretched using a stretching device equipped with a pair of toothed rollers as shown in Fig. 7 to produce stretchable sheets as shown in Figs. 1 and 2, which were used as diapers Outer packaging materials, making a shorts-type disposable diaper with a waist circumference of 35cm. As shown in Fig. 9, the diaper was put on an acrylic tube having a circumference of 44 cm, the lower part of the diaper was fixed with an alligator clip, the clip was moved upward, and the acrylic tube was placed on a jack. At this time, the waist position of the diaper was marked on the acrylic tube (the position at this time was defined as initial position A), and the jack was lowered by 50 mm while the clip was fixed. The distance between the waist position after the jack was lowered by 50 mm (the position at this time was defined as the offset position) and the initial position A was measured, and this distance was defined as the offset drop amount of the diaper. The case where the amount of this deviation and drop is less than 10 mm is judged as ◎ (prevention of diaper deviation and drop is very good), the case of 10 mm or more but less than 20 mm is judged as ○ (diaper deviation and drop resistance is good), and the case of 20 mm The case of more than 30 mm but less than 30 mm was judged as Δ (a level that is practically no problem), and the case of 30 mm or more was judged as ×. the

From the results shown in Table 2 and Table 3, it can be seen that since Examples 2-1 to 2-5 all used the resin composition within the scope of the present invention, the spinning formability of the filament was excellent, and it was long in the stretch sheet. There are no twists and turns in the thread, and when the stretch sheet is used for diapers, it is possible to obtain a diaper that is difficult to fall off. On the other hand, in Comparative Example 2-1, the thickness of the filaments became non-uniform due to the die swell, and the filaments were broken from the very thin portions, so that continuous filaments could not be obtained. In Comparative Example 2-2, although the thickness was uniform, the melt tension was low, so the filaments were broken and continuous filaments could not be obtained. Therefore, when the stretch sheets obtained in Comparative Examples 2-1 and 2-2 were used for diapers, the stretching properties were lowered due to the breakage of the filaments, so that the deflection drop property deteriorated. In Comparative Example 2-3, since the viscosity of the triblock copolymer (8) was high, it could not be spun and formed, so a filament could not be obtained. the

[Example 3-1]

The stretch sheet having the structure shown in Fig. 1 and Fig. 2 was manufactured using the apparatus shown in Fig. 5 . As the first and second nonwoven fabrics 11 and 12, an air-through nonwoven fabric having a basis weight of 20 g/m ² and a fiber density of 0.074 g/cm ³ was used. The constituent fibers of this nonwoven fabric are core-sheath composite fibers (core: PET; sheath: PE) having a diameter of 19 μm, a maximum elongation of 180%, and a fiber length of 44 mm. As the raw material resin of the elastic filament 13, an elastomer composed of SEPS resin (weight-average molecular weight: 50,000; MFR: 60 g/10 minutes (230° C., 2.16 kg)) was used. The spinning conditions were as follows: the temperature of the spinning head 17 was 310° C., the diameter of the spinning nozzles 16 was 400 μm, the pitch of the spinning nozzles 16 was 1 mm, and the draw ratio was 11 times. The elastic filament 13 has a diameter of 107 μm. The weight per unit area of the filament was 8 g/m ² . The gap W between the nip rolls was set in joining the elastic filaments and the nonwoven fabrics 11 and 12, and the gap was set to 0.2 mm. One of the pinch rollers uses a metal flat roller, and the other uses a rubber roller. Stretching of the composite 19 is performed using a stretching device 22 including a pair of toothed rolls 20 and 21 alternately formed with teeth and grooves in the axial direction. The pitch between the teeth and the pitch between the teeth was 2.0 mm (the pitch P between the teeth in the meshing state was 1.0 mm). The pressing amount of the upper and lower toothed rollers was adjusted, and the composite 19 was stretched in the stretching direction of the elastic filament 13 at a stretching ratio of 3.0 times. Thus, a stretchable sheet 10 with a basis weight of 48 g/m ² stretchable in the extending direction of the elastic filaments 13 was obtained. The obtained stretchable sheet 10 presents a striped pattern produced by the elastic filaments 13 through the non-woven fabric. In addition, the striped pattern produced by the high basis weight region and the low basis weight region was also exhibited. With these two stripe patterns, the stretch sheet also presents a checkered pattern. In addition, the elastic filaments 13 in the stretchable sheet 10 have an elliptical cross-section whose long axis is in the plane direction of the sheet 10, and the ratio of the long axis/short axis is 1.5. The width reduction when stretched 1.5 times is 4%. .

[Example 3-2～3-4]

A stretch sheet 10 was obtained in the same manner as in Example 3-1 except that the interval W between the nip rolls was set to the value shown in Table 4 and Table 5. the

[Example 3-5～3-7]

Except that the distance from the tip of the spinning nozzle to before joining is set to the values shown in Table 4 and Table 5, and the entire surface extrusion is performed without gaps between nip rolls during joining, the same as in Example 3- 1. Perform the same operation to obtain a stretchable sheet 10. the

[Comparative Example 3-1]

A stretch sheet was obtained in the same manner as in Example 3-1 except that a film-like elastic resin extruded from a T-die was used instead of the elastic filaments, and the film-like elastic resin was laminated on a nonwoven fabric. As the elastic resin, G1657 (trade name, manufactured by Kraton Polymers) was used. the

[evaluate]

Each item shown in Table 4 and Table 5 was measured and evaluated about the stretch sheet obtained in the Example and the comparative example. In Table 4 and Table 5, "interlaminar peel strength" (bonding strength between elastic filament and nonwoven fabric), "25% recovery strength (cN/{50mm·(g/m ² )})" (unit 25% recovery strength per unit area weight of the elastic resin contained in the stretch sheet), "average bonding ratio between elastic filaments and non-woven fabric constituting fibers", "width reduction (%)" (stretch the stretch sheet Width reduction when 1.5 times longer), and the thickness of the stretch sheet and nonwoven fabric were measured by the above-mentioned methods, respectively. In addition, "25% recovery strength (cN/50mm)", "25% recovery strength/25% elongation strength (%)", and "touch" were measured and evaluated by the following methods, respectively. In addition, "intersection of elastic filaments" was performed by visual observation. The case where the intersection of the elastic filaments was hardly observed was the highest evaluation, and the case where the intersection was observed was the low evaluation.

[25% Recovery Strength/25% Elongation Strength, 25% Recovery Strength] 

A test piece is cut out from the stretchable sheet to a size of 200 mm in the stretching direction and 50 mm in a direction perpendicular to the stretching direction. A test piece was mounted and fixed on a tensile tester (Autograph AG-1kNIS manufactured by Shimadzu Corporation) so that the distance between chucks (initial length) was 150 mm. Make the test piece elongate at a rate of 300 mm/min in the stretching direction, record the load at the time of 25% elongation, and use this value as the 25% elongation strength. Continue to stretch the test piece to 50%, then immediately shrink it in the recovery direction (shrinkage direction) at the same speed, and record the load when it is stretched to 25% of the initial length, and use it as the 25% recovery strength. Using the values of the 25% elongation strength and the 25% recovery strength thus obtained, respectively, 25% recovery strength/25% elongation strength (%) was calculated. The above measurements are carried out in an environment with a temperature of 20±2° C. and a humidity of 65±5% RH. the

[feel]

Ten female evaluators evaluated the feel of the stretch sheet in an environment with a temperature of 25° C. and a humidity of 40% in a dark box where the stretch sheet could not be seen. Based on the evaluation by each evaluator, the following points were used for scoring, and the average score (rounded up to one decimal point) of 10 evaluators was used as the evaluation score of texture. the

5 points: Feel good. the

4 points: Feeling is slightly better. the

3 points: average. the

2 points: Feeling slightly poor. the

1 point: The hand feeling is poor. the

Table 4

table 5

From the results shown in Table 4 and Table 5, it can be seen that the stretch sheets of each embodiment show the desired average bonding ratio, and have a higher interlayer peel strength (bonding strength between the elastic filament and the nonwoven fabric) And high 25% recovery strength (25% recovery strength per unit area weight of the elastic resin in the stretch sheet), the width reduction is small, the intersection of elastic filaments is hardly observed, and the hand feeling is also excellent. In addition, the stretch sheet of each Example had the appearance shown in FIG. 2, and the appearance was also favorable. In contrast, the elastic resin in the stretch sheet of Comparative Example 3-1 had a low 25% recovery strength per unit area weight, a large width reduction, and no air permeability. the

As described above, in the stretchable sheet of the present invention, since the elastic filaments are arranged to extend in one direction, the stretchable sheet can be stretched in the direction in which the elastic filaments extend without reducing the width. In addition, the stretchable sheet of the present invention has high strength, and when the stretchable sheet is stretched, the elastic filaments and the nonwoven fabric are less likely to be peeled off. the

In addition, in the stretchable sheet of the present invention, a large number of elastic filaments are arranged to extend in one direction with respect to an extensible nonwoven fabric composed of non-elastic fibers, and the elastic filaments and the nonwoven fabric The bonding strength between them, the 25% recovery strength per unit area weight of the elastic resin in the stretch sheet, and the average bonding ratio between the elastic filaments and the fibers constituting the nonwoven fabric are respectively within the above-mentioned specified ranges, so The balance between the interlayer joint strength and stretch properties is excellent, and the stretch sheet can be stretched along the extending direction of the elastic filaments without width reduction, and when the stretch sheet is stretched, It is not easy to cause peeling of elastic filaments and non-woven fabrics. the

In addition, the elastic filament of the present invention has excellent spinning formability, and can be ejected from the spinning nozzle without breaking or twisting even in the case of a small diameter, and can be processed at high speed. Production. When the elastic sheet of the present invention composed of such elastic filaments is used, for example, as a forming material of various kinds of clothing represented by absorbent articles such as disposable diapers, and other various articles worn on the human body, due to the elasticity The role of the filaments, showing excellent fit, can effectively prevent the deviation of wearing clothes from falling. The absorbent article of the present invention comprising the stretchable sheet has excellent fit during wearing and is difficult to fall off. the

Claims (18)

1. flexible sheet material; Its for a large amount of elastic filament on its whole length with in fact not the state of elongation engage with tensile nonwoven and form; Said a large amount of elastic filament is arranged according to the mode of not extending along a direction across each other; Wherein, tensile said nonwoven contains along the different non-elastic fiber of the fineness degree of fibre length direction.

2. flexible sheet material according to claim 1, wherein, said elastic filament engages through melt bonded with said nonwoven.

3. flexible sheet material according to claim 1 and 2, wherein, said elastic filament is to form through elastic resin is stretched under fusion or softening state.

4. flexible sheet material according to claim 3, wherein, said elastic filament through will be from spinning-nozzle spun elastic resin carry out fusion drawn and obtain.

5. flexible sheet material according to claim 3, wherein, said elastic filament reaches said elastic resin 1.1～400 times and obtains in that fusion or softening state are drop-down, and the diameter of said elastic filament is 10～200 μ m.

6. flexible sheet material according to claim 1 and 2; Wherein, In said flexible sheet material; Said elastic filament roughly disposes with respect to this prolonging direction in the different zone more than 2 of the elongation stress on the prolonging direction side by side, and between each zone, the spacing of adjacent said elastic filament diameter different and/or said elastic filament is different.

7. flexible sheet material according to claim 1 and 2, wherein, said elastic filament is clamped between 2 identical or different nonwoven.

8. flexible sheet material according to claim 1 and 2, wherein, the average flat ratio of said elastic filament is 1.0～7.0 times.

9. flexible sheet material according to claim 1 and 2, wherein, the fineness degree of said non-elastic fiber is 2～15 μ m at its thinnest part place, is 10～40 μ m at its thickest part place.

10. flexible sheet material according to claim 1, wherein, said non-elastic fiber is the short fiber that is made up of composite fibre.

11. flexible sheet material according to claim 1 and 2; Wherein, Bond strength between said elastic filament and the said nonwoven is more than the 10cN/25mm; 25% answer intensity is 1.0cN/{50mm (g/m2) with respect to the per unit area weight of the elastic resin that is contained in the said flexible sheet material } more than, and the average splice ratio between the fiber of said elastic filament and the said nonwoven of formation is 10～60%.

12. flexible sheet material according to claim 1 and 2; Wherein, The resin combination that said elastic filament constitutes by containing A1-B-A2 type triblock copolymer forms, and said A1-B-A2 type triblock copolymer is by being polymer blocks A1 and the A2 of main body with the vinyl aromatic polymers and being that the polymer blocks B of main body constitutes with the polyolefin;

Said polymer blocks A1 and the A2 weight average molecular weight of passing through gel permeation chromatography separately add up to 14000～20000, and the weight average molecular weight of passing through gel permeation chromatography of said polymer blocks B is 40000～80000.

13. flexible sheet material according to claim 12; Wherein, Said resin combination is that 0.45mm, length are that the maximum of the fusion tension force during with 8.4m/ minute spouting velocity ejection the nozzle bore of drum of 4.5mm is 0.06～0.20cN from internal diameter under the state with 245 ℃ temperature heating and melting.

14. the manufacturing approach of a flexible sheet material; Wherein, Will be from spinning-nozzle a large amount of elastic filament of spun molten condition with the fixing speed tractive and stretch; And before this elastic filament solidified, the mode of not arranging along a direction across each other according to said elastic filament made said elastic filament and nonwoven melt bonded, then the bearing of trend of the melt bonded complex that said elastic filament arranged along said elastic filament was stretched; Thereby make said complex have retractility

Wherein, Said fixing speed is the spin speed of said elastic filament from said spinning-nozzle that is adjusted into respect to molten condition; Its stretching ratio is 1.1～400 times a speed, and said nonwoven contains along the different non-elastic fiber of the fineness degree of fibre length direction.

15. the manufacturing approach of flexible sheet material according to claim 14, wherein, through making the said nonwoven in said elastic filament and the conveyance melt bonded, thereby with said elastic filament tractive and stretch.

16. manufacturing approach according to claim 14 or 15 described flexible sheet materials; Wherein, Said complex is passed through between a pair of tooth space roller along its moving direction; Thereby the moving direction along said complex makes said complex have retractility, and said a pair of tooth space roller alternately is formed with tooth and roller seating space in a circumferential direction.

17. the manufacturing approach of a flexible sheet material; Its will be from spinning-nozzle a large amount of elastic filament of spun molten condition with the fixing speed tractive and stretch; And before said elastic filament solidifies; The mode of each other not arranging along a direction across according to said elastic filament makes said elastic filament and nonwoven melt bonded; Then the bearing of trend of the melt bonded complex that said elastic filament arranged along said elastic filament stretched, thereby make said complex have retractility

Wherein, At spun said elastic filament from said spinning-nozzle with before said nonwoven contacts; The displacement that said elastic filament is started at from the top of said spinning-nozzle is below the 600mm; Said fixing speed is the spin speed of said elastic filament from said spinning-nozzle that is adjusted into respect to molten condition, and its stretching ratio is 1.1～400 times a speed, and said nonwoven contains along the different non-elastic fiber of the fineness degree of fibre length direction.

18. the manufacturing approach of flexible sheet material according to claim 17; Wherein, The melt bonded of said elastic filament and said nonwoven is between a pair of niproll, to collaborate to carry out through said elastic filament and the said nonwoven in the conveyance that makes spun molten condition from said spinning-nozzle, is spaced apart 0.05～1.0mm between the said a pair of niproll.

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