WO2010024249A1 - Leather-like sheet and manufacturing method thereof - Google Patents

Abstract

A method for manufacturing a leather-like sheet (10) that is characterized by having a first polyurethane layer formation step in which a first polyurethane layer (2) is formed by applying a heat melted hot-melt type moisture-cured polyurethane (2) on the surface of a base fabric (1) or a release sheet, a porous sheet adhesion step in which a porous sheet (3) is adhered to the first polyurethane layer (2), and a second polyurethane layer formation step in which a second polyurethane layer (4) is formed on the outer surface of the porous sheet (3).

Description

Leather-like sheet and manufacturing method thereof

The present invention relates to a leather-like sheet formed from a polyurethane laminate and a method for producing the same.

Conventionally, a leather-like sheet made of a polyurethane laminate has been widely used as a surface material for footwear, clothing, bags, furniture, and the like.

As a typical configuration of such a leather-like sheet, a composite fiber base material in which a fibrous base material such as a nonwoven fabric, a woven fabric, or a knitted fabric is impregnated with polyurethane is used as a base fabric, and the surface of such a base fabric is used. An example is a structure in which after an intermediate layer made of polyurethane is laminated, a silver surface layer formed of polyurethane, acrylic resin or the like is further formed on the surface of the formed intermediate layer. The intermediate layer is formed by applying a solvent-type polyurethane or water-based polyurethane to the surface of the base fabric and then drying, or by adhering a polyurethane film previously formed on the surface of the release paper to the surface of the base fabric with an adhesive. It is formed using.

By the way, in recent years, in order to reduce the environmental burden, in the polyurethane product production field, a process using an aqueous polyurethane or a solventless polyurethane which does not use a large amount of an organic solvent is required. In the production of leather-like sheets, some processes using water-based polyurethane have been put into practical use. However, water-based polyurethanes have not yet sufficiently replaced solvent-based polyurethanes due to poor water resistance, durability, etc., or low drying efficiency.

For example, Patent Document 1 below discloses a method of using a hot-melt moisture-curing polyurethane as a method for producing a leather-like sheet that can reduce the amount of organic solvent used. Specifically, [FIG. 3] of Patent Document 1 describes a method of bonding a film layer made of hot-melt type moisture-curing polyurethane on a substrate with an adhesive made of hot-melt type moisture-curing polyurethane. ing. Hereinafter, this method will be described in detail.

FIG. 1 shows a drawing quoting [FIG. 3] described in Patent Document 1. In FIG. 1, 30 is a delivery reel of release paper (release paper) 301, 36 is a delivery reel of a base material 37, 38 is a take-up reel of a leather-like sheet as a product, 31, 32, 33a, 33b, 34 , 35 are rollers, 303 and 305 are knife coaters for applying hot-melt type moisture-curing polyurethane 312, 314, and 304 is a steam sprayer.

In FIG. 1, the release paper 301 wound around the delivery reel 30 is carried on rollers 31 and 32. Then, a coating layer is formed by applying a hot-melt type moisture-curing polyurethane 312 in a molten state to the surface of the release paper 301 with a knife coater 303. Subsequently, water vapor is sprayed onto the film layer made of the hot-melt type moisture-curing polyurethane 312 with the water vapor sprayer 304. Then, it is placed on the rollers 33a and 33b and sent to the roller 34, and a hot-melt type moisture-curing polyurethane 314 in a molten state is further applied as an adhesive on the coating layer made of the hot-melt type moisture-curing polyurethane 312 with the knife coater 305. To do. Then, the base material 37 is supplied from the delivery reel 36, and the base material 37 is bonded to the adhesive layer of the hot-melt type moisture-cure polyurethane with the roller 35 to manufacture a leather-like sheet.

JP 2000-54272 A

When a film layer or an adhesive layer is formed using a solvent-free hot-melt moisture-curing polyurethane as described in Patent Document 1, the solvent-free process can be realized. However, when a leather-like sheet is industrially continuously produced using the method as described above, there are the following problems.

Hot-melt type moisture-cure polyurethane is heated and melted during application and applied onto a substrate or release paper. And it solidifies again by cooling to predetermined temperature after application | coating. The coating workability which was excellent by such heat melting property is exhibited. Immediately after re-solidification, the curing reaction does not proceed sufficiently, and thus the surface remains tacky (tack). Then, the curing reaction proceeds with a high molecular weight by moisture in the air, water vapor jetted in the process, etc., and tack disappears when the curing reaction is completed.

In the process as shown in FIG. 1, a film layer made of hot-melt type moisture-cured polyurethane 312 applied in a molten state to the surface of the release paper 301 is sprayed with water vapor by a water vapor sprayer 304, and then a roller 33a. , 33b and sent to the roller 34. In such a process, the curing reaction is accelerated by spraying water vapor. And it seems that smooth conveyance property is going to be ensured by accelerating hardening reaction and suppressing tackiness. However, when the coating layer formed from the hot-melt type moisture-curing polyurethane 312 that is not sufficiently cured has come into contact with the surfaces of the rollers 33a and 33b, the tack remaining on the surface of the hot-melt type moisture-curing polyurethane 312. As a result, the film layer of the hot-melt moisture-curing polyurethane 312 adheres to the surfaces of the rollers 33a and 33b and wraps around the rollers 33a and 33b, thereby causing a problem of hindering smooth conveyance. Also, when the polyurethane layer is laminated after the film layer formed from the hot-melt moisture-curing polyurethane 312 is sufficiently crosslinked and cured, the transportability is improved, but the hot-melt moisture that is laminated is improved. Adhesiveness with a layer made of a partially cured polyurethane was not sufficiently high.

As described above, when a leather-like sheet is continuously produced in an industrial process using a hot-melt type moisture-curing polyurethane, it may be difficult to smoothly convey the laminated intermediate immediately after application using a roller or the like. There was a problem that the adhesive strength of the laminate was not sufficient.

In order to solve the above problems, the present invention provides a hot-melt type moisture-curing polyurethane film having tackiness in the case where a coating layer is formed on the surface of a base fabric or a release paper using a hot-melt type moisture-curing polyurethane. An object of the present invention is to provide a method for producing a leather-like sheet using a hot-melt type moisture-cured polyurethane that can suppress a decrease in productivity due to direct contact with a roller or the like and has high adhesion between laminations. .

One aspect of the present invention is a first polyurethane layer forming step of forming a first polyurethane layer by applying hot melt moisture-cured polyurethane heated and melted on a surface of a base fabric or a release paper, and the first polyurethane layer. A method for producing a leather-like sheet, comprising: a porous sheet laminating step for laminating a porous sheet on the surface; and a second polyurethane layer forming step for forming a second polyurethane layer on the outer surface of the porous sheet. It is.

Another aspect of the present invention is a base fabric, a first polyurethane layer formed from a hot-melt type moisture-cured polyurethane laminated on the surface of the base fabric, and laminated on the surface of the first polyurethane layer. A leather-like sheet comprising a porous sheet and a second polyurethane layer laminated on the porous sheet.

The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

FIG. 1 is a drawing in which [FIG. 3] described in Patent Document 1 is cited. FIG. 2 is a schematic process diagram illustrating a method for manufacturing a leather-like sheet according to the first embodiment. FIG. 3 is a schematic cross-sectional view of the leather-like sheet obtained by the process of the first embodiment. FIG. 4 is a schematic process diagram illustrating a method for manufacturing a leather-like sheet according to the second embodiment. FIG. 5 is a schematic cross-sectional view of the leather-like sheet obtained by the process of the first embodiment. FIG. 6 is a schematic process diagram illustrating a method for manufacturing a leather-like sheet according to the third embodiment. FIG. 7 is a schematic process diagram illustrating a method for producing a laminated intermediate body of a polyurethane laminate according to the fourth embodiment. FIG. 8 is a schematic process diagram illustrating a process of applying a second polyurethane layer by spraying to the nonwoven fabric surface side obtained by heating and smoothing the nonwoven fabric surface of the laminated intermediate wound in FIG. It is. FIG. 9 illustrates a process of applying the second hot-melt type moisture-curing polyurethane on the release paper, and bonding the nonwoven fabric surface of the laminated intermediate wound up in FIG. 7 with the heat-smoothed nonwoven fabric surface side. It is a schematic process drawing. FIG. 10 is a schematic process diagram illustrating a method for manufacturing a leather-like sheet of Comparative Example 2.

[First Embodiment]
The method for producing a leather-like sheet according to the present embodiment comprises applying a first melted polyurethane by applying hot-melt type moisture-cured polyurethane (hereinafter also simply referred to as moisture-cured polyurethane) heated and melted to the surface of a base fabric or release paper. A first polyurethane layer forming step for forming a layer, a porous sheet laminating step for laminating a porous sheet to the first polyurethane layer, and a second polyurethane for forming a second polyurethane layer on the outer surface of the porous sheet A layer forming step.

Hereinafter, the first embodiment will be described with reference to FIG.

FIG. 2 is a schematic process diagram for explaining a method for producing a leather-like sheet according to this embodiment. In FIG. 2, 1 is a base fabric, 2 is a first moisture-curing polyurethane, 3 is a porous sheet, 4 is a second moisture-curing polyurethane, and 5 is a release paper. Reference numeral 11 denotes a delivery reel for the base cloth 1, 12 denotes a delivery reel for the porous sheet 3, 13 denotes a delivery reel for the release paper 5, and 14 denotes a take-up reel for the leather-like sheet 10 covered with the release paper 5. Furthermore, 20, 22, 23, 24a, 24b, 25, 27, and 28 are transport rollers. Reference numerals 100 and 101 denote calendar rolls. Reference numerals 21 and 26 denote reverse roll coaters equipped with heating rolls, and 102 and 104 denote resin feeders equipped with heaters (not shown).

In the process of FIG. 2, first, the base cloth 1 is sent out from the feed reel 11 through the rollers 20, 22, 23, 24 a, 24 b, and 27 toward the take-up reel 14 to form a line of the base cloth 1. .

Then, the first moisture-curing polyurethane 2 accommodated in the resin feeder 102 and heated and melted is flowed toward the base cloth 1 on the line while maintaining the molten state. Then, the first moisture-curing polyurethane 2 is applied in a molten state with a uniform thickness on the surface of the base fabric 1 by the heated reverse roll coater 21 (first polyurethane layer forming step).

Specific examples of the base fabric 1 used in the present embodiment include, for example, fiber base materials generally used for leather-like sheets such as non-woven fabrics, woven fabrics, and knitted fabrics; Examples thereof include composite fiber base materials impregnated with water-based, emulsion-based or solvent-free polyurethane resins, acrylic resins, butadiene-based resins (SBR, NBR, MBR) and the like. In these, the composite fiber base material which impregnated the polyurethane resin to the nonwoven fabric formed from the ultrafine fiber is used especially preferable from the point from which the leather-like sheet | seat which has a soft texture and more excellent mechanical strength is obtained.

Next, the hot melt moisture-curing polyurethane used in this embodiment will be described.

The hot-melt type moisture-cure polyurethane is a polyurethane-forming component having a hot-melt property and a moisture-curing property containing a urethane prepolymer obtained by reacting a polyol and a polyisocyanate as a main component.

The hot-melt property of moisture-cured polyurethane is solid at room temperature or has a viscosity that is difficult to apply, but it becomes a viscosity that can be applied by heating and melting, and re-solidifies by cooling. Expresses adhesiveness. As described above, the moisture-curing polyurethane can be applied to a base fabric, a release paper, or the like in a heated and melted state, and after application, the viscosity is rapidly increased and re-solidified by cooling.

On the other hand, the moisture-curing property of moisture-curing polyurethane is based on a curing reaction in which the isocyanate group terminal in the urethane prepolymer reacts with moisture (water) to form a urethane bond or a urea bond. Further, the formed urethane bond or urea bond also depends on a crosslinking reaction by reacting with an isocyanate group present in the system. And through such a curing reaction and a crosslinking reaction, a polyurethane cured product having excellent mechanical properties and moisture resistance is formed by increasing the molecular weight.

In contrast to the cooling and solidification that occurs in a short time, the moisture curing reaction of the moisture-curing polyurethane is completely cured over a relatively long time, for example, about 20 to 50 hours. Therefore, immediately after coating by heating and melting, and immediately after cooling and solidifying, remarkable tackiness (tackiness) remains on the surface. Then, the tack disappears as the curing and crosslinking reaction proceed to increase the molecular weight.

The number average molecular weight of the urethane prepolymer in the hot melt moisture-curing polyurethane is preferably in the range of 500 to 30,000, more preferably 1000 to 10,000. When the number average molecular weight of the urethane prepolymer is in such a range, a polyurethane layer having excellent flexibility, mechanical strength, abrasion resistance, and hydrolysis resistance can be formed.

The melt viscosity of the hot melt moisture-cured polyurethane is preferably in the range of 100 to 10,000 mPa · s, more preferably 1000 to 8000 mPa · s, at 125 ° C. as measured with a cone plate viscometer.

The moisture-curing polyurethane in the present invention is usually a resin component mainly composed of a polyurethane prepolymer, a urethanization catalyst, a colorant such as a pigment, a thickener, a crosslinking agent, a crosslinking accelerator, an antioxidant, etc. Used as a resin composition containing additives. Moreover, when forming a 1st polyurethane layer as a foaming polyurethane layer, a foaming agent is mix | blended. Such a resin composition can be obtained by uniformly mixing a resin component mainly composed of a polyurethane prepolymer and other components in a heated and melted state.

Specific examples of an apparatus for heating and melting hot melt type moisture-curing polyurethane and applying it to the surface of the base fabric 1 include the above-mentioned reverse roll coater, for example, knife coater, reverse coater, kiss roll coater, roll coater, spray coater. , T-die coater, comma coater or the like can be used. In particular, a reverse roll coater or a roll coater provided with a heating roll is preferable from the viewpoint that the molten state of the hot-melt type moisture-curing polyurethane can be maintained.

The melt viscosity at the time of application is preferably in the range of 1000 to 15000 mPa · s, more preferably 2000 to 10000 mPa · s from the viewpoint of excellent coating workability.

The thickness of the first polyurethane layer 2 to be formed is in the range of 5 to 800 μm, more preferably 10 to 500 μm after curing, and a leather-like sheet having excellent flexibility and mechanical strength can be obtained. It is preferable from the point which is made.

Next, the porous sheet 3 is delivered from the delivery reel 12 toward the surface of the application layer of the first moisture-curing polyurethane 2 in a molten or softened state. And the porous sheet 3 is bonded by the calender roll 100 to the coating layer surface of the 1st moisture hardening polyurethane 2 (porous sheet bonding process). In this way, by coating the surface of the application layer of the moisture-curing polyurethane 2 with the porous sheet 3, it is possible to suppress the adverse effect of the tack property of the uncured moisture-curing polyurethane 2 on the process.

Examples of the porous sheet 3 include fiber base sheets such as nonwoven fabrics, woven fabrics, and knitted fabrics obtained by known methods such as a spunbond method and a melt blow method, and foamable resins such as foamable polyurethane sheets. A sheet can be used without particular limitation. In particular, when a fiber base sheet is used, the moisture-cured polyurethane in a molten state sinks into the fiber base, and the polyurethane grips the fiber, so that the first moisture curing is performed by an anchor effect. This is preferable in that the adhesiveness between the polyurethane layer and the second moisture-curing polyurethane layer is excellent. Further, it is preferable to use a non-woven fabric because a regular pattern such as a woven fabric or a knitted fabric is hardly expressed on the surface of the leather-like sheet and it is easy to maintain an irregular smooth feeling like natural leather.

Specific examples of fibers forming the nonwoven fabric used as the porous sheet 3 include, for example, polyurethane fibers, polyethylene terephthalate (PET) fibers, various polyamide fibers, various polyolefin fibers, polyvinyl alcohol fibers, and the like. In these, a polyurethane fiber is preferable from the point which is excellent in the adhesiveness with a 1st polyurethane layer and a 2nd polyurethane layer, and a sense of unity.

The fibers forming the nonwoven fabric are preferably ultrafine fibers having a fiber diameter of 0.1 to 50 μm, more preferably 1 to 15 μm. Such ultrafine fibers are preferred because they have a low rigidity and are soft, so that a leather-like sheet having a soft texture can be obtained.

The non-woven fabric may be obtained by forming a web and then superimposing a plurality of webs so that they are entangled by needle punching or the like.

The basis weight of the nonwoven fabric is preferably in the range of 10 to 100 g / m ² , more preferably in the range of 20 to 60 g / m ² , from the viewpoint of obtaining a leather-like sheet having a soft texture and excellent processability.

On the other hand, as the foamable resin sheet, a resin sheet having a foam structure can be used without any particular limitation. Specific examples thereof include a foamable polyurethane sheet, a foamable acrylic sheet, a foamable polyester sheet, a foamable olefin-based sheet, and a foamable polyamide-based sheet. In these, a foamable polyurethane sheet is preferable from the point which is excellent in adhesiveness with a 1st polyurethane layer and a 2nd polyurethane layer, and a sense of unity.

The thickness of the foamable resin sheet is preferably 5 to 100 μm, more preferably 10 to 50 μm.

As the method for bonding the porous sheet 3 to the surface of the coating layer of the first moisture-cured polyurethane 2 in a molten or softened state, the above calender roll can be preferably used.

In addition, when using a thermoplastic resin nonwoven fabric such as a polyurethane nonwoven fabric as the porous sheet, a heating calender roll is used when the thermoplastic resin nonwoven fabric is bonded to the surface of the first moisture-curing polyurethane 2 coating layer. Thus, it is preferable that the thermoplastic resin nonwoven fabric is bonded while being smoothed by heating and pressing. Since the nonwoven fabric has a relatively large amount of internal space, the apparent density is low. Therefore, by bonding the thermoplastic resin nonwoven fabric to the first polyurethane layer while heating and pressing, the thermoplastic resin nonwoven fabric having a large number of spaces is smoothed and compressed into a sheet having an appropriate gap. Thereby, since a porosity can be adjusted moderately, intensity | strength can be improved. In addition, the adhesion between the first polyurethane layer and the porous sheet is improved.

Next, the laminated intermediate formed by laminating the porous sheet 3 passes through the rollers 23, 24 a, 24 b, and 25, and is directed directly below the resin feeder 104 that houses the second moisture-curing polyurethane 4. Are transported. Then, the second moisture-curing polyurethane 4 accommodated in the resin feeder 104 flows down in a molten state onto the surface of the porous sheet 3 of the laminated intermediate, and is applied with a uniform thickness by the reverse roll coater 26 (the first thickness). 2 polyurethane layer forming step).

As the second moisture-curing polyurethane 4, the same one as used in the first moisture-curing polyurethane 2 described above is used. In addition, when the 2nd moisture hardening polyurethane 4 forms the skin of a leather-like sheet | seat, the moisture hardening polyurethane of the compounding composition which provided the desired skin function is used. The same coating method and coating conditions as those used in the first moisture-curing polyurethane 2 can be used.

Then, the release paper 5 is delivered from the delivery reel 13, and is bonded to the release paper 5 by the calendar roll 101 in a state where the applied second moisture-curing polyurethane 4 is melted or softened (sheet bonding step). . In this way, the leather-like sheet 10 is formed. Then, the obtained leather-like sheet 10 is taken up by the take-up reel 14 while being covered with the release paper 5. And the moisture hardening reaction of the 1st moisture hardening polyurethane 2 and the 2nd moisture hardening polyurethane 4 advances by aging for a predetermined time in the wound state.

As the release paper 5, in addition to a release paper having a smooth surface, a release paper having an embossed pattern may be used for the purpose of imparting surface design properties.

The aging conditions of the obtained leather-like sheet 10 are preferably aging for about 20 to 50 hours at a temperature of 20 to 40 ° C. and a relative humidity of 50 to 80%. By aging under such aging conditions, the moisture-cured polyurethane is moisture-cured and moisture-crosslinked, whereby a leather-like sheet having excellent mechanical strength and water resistance can be obtained. In addition, the leather-like sheet | seat 10 peels the release paper 5 coat | covered on the surface.

In the process as described above, the surface of the coating layer of the first moisture-curing polyurethane 2 is covered with the porous sheet 3 before coming into contact with the surfaces of the rollers 24a and 24b. Therefore, in the process after being coated with the porous sheet 3, the adverse effect due to the tackiness of the uncured first moisture-cured polyurethane 2 does not reach the production line. Therefore, since conveyance by each roller becomes smooth, continuous production can be stabilized.

FIG. 3 shows a schematic cross-sectional view of the leather-like sheet 10 obtained by such a process.

As shown in FIG. 3, the leather-like sheet 10 is completed by peeling the release paper 5 coated on the surface. In such a leather-like sheet 10, the first moisture-curing polyurethane layer 2 and the second moisture-curing polyurethane 4 are bonded via the porous sheet 3. Therefore, the adhesive force with the 1st moisture hardening polyurethane layer 2 and the 2nd moisture hardening polyurethane layer 4 can be heightened by the anchor effect by the space | gap of the porous sheet 3. FIG.

[Second Embodiment]
Next, a second embodiment will be described with reference to FIG.

In addition, since the part which attached | subjected the code | symbol similar to 1st Embodiment is a part which is common in 1st Embodiment, detailed description is abbreviate | omitted.

FIG. 4 is a schematic process diagram illustrating a method for manufacturing the leather-like sheet 50 of the second embodiment. In the process of 2nd Embodiment, it is the same as that of the process of 1st Embodiment until the porous sheet bonding process in which the porous sheet 3 is bonded to the coating layer surface of the 1st moisture hardening polyurethane 2. FIG. On the other hand, the second polyurethane layer is formed by adhering a polyurethane film 42 formed in advance on the surface of the release paper 5 to the outer surface of the porous sheet 3 with an aqueous polyurethane adhesive 44.

In FIG. 4, 44 is a water-based polyurethane adhesive, and 45 is a polyurethane film with release paper having a polyurethane film 42 formed on the surface of the release paper. Reference numeral 43 denotes a delivery reel for the polyurethane film 45 with release paper. Furthermore, 20, 22, 23, 24a, 24b, 25, 26, 27, and 28 are transport rollers. In addition, 21 is a reverse roll coater provided with a heating roll, and 154 is a knife coater.

In FIG. 4, the process up to the porous sheet bonding process is the same as the process shown in FIG. The laminated intermediate formed by laminating the porous sheet 3 is conveyed through the rollers 23, 24 a, 24 b, 25 toward the lower part of the resin feeder 144 that contains the aqueous polyurethane adhesive 44. Then, the aqueous polyurethane adhesive 44 accommodated in the resin feeder 144 flows down to the surface of the porous sheet 3 on the surface layer of the laminated intermediate, and is applied to the surface of the porous sheet 3 with a uniform thickness by the knife coater 154. . Then, the adhesive layer 47 is formed by drying with a drying furnace 46. Then, the polyurethane film 45 with release paper fed from the delivery reel 43 is merged, and the calendar layer 101 is used to bond the adhesive layer 47 and the polyurethane film 42 on the surface of the polyurethane film 45 with release paper so as to face each other (second). Polyurethane layer forming step). Thereby, the leather-like sheet 50 is formed.

In the process of the second embodiment, the second polyurethane layer is formed by adhering the polyurethane film 42 on the surface of the polyurethane film 45 with release paper to the outer surface of the porous sheet 3 with the adhesive layer 47. Even in such a process, since the surface of the application layer of the moisture-curing polyurethane 2 is previously covered with the porous sheet 3, the tack property of the uncured moisture-curing polyurethane 2 prevents smooth roller feeding. There is no.

As the aqueous polyurethane that can be used for forming the adhesive layer 47, a polyurethane aqueous dispersion, a polyurethane emulsion, or the like that has been conventionally used for interlayer adhesion when a leather-like sheet is produced can be preferably used. In the present embodiment, aqueous polyurethane is used for the purpose of reducing the amount of organic solvent used, but solvent-based polyurethane may be used instead of aqueous polyurethane. The thickness of the adhesive layer 47 is preferably in the range of 10 to 100 μm, more preferably 20 to 60 μm, from the viewpoint of obtaining a leather-like sheet excellent in flexibility and mechanical properties.

The polyurethane film 45 with release paper is not particularly limited as long as the polyurethane film 42 for forming the second polyurethane layer is previously formed on the release paper surface. Examples of the polyurethane film 42 on the surface of the release paper include films formed from hot melt type (moisture curing) polyurethane, aqueous polyurethane, solvent type polyurethane, and the like. Among these, a film formed from hot-melt type polyurethane and aqueous polyurethane is preferable from the viewpoint that the amount of organic solvent used can be suppressed, and in particular, a film formed from hot-melt type moisture-cured polyurethane. Is preferable from the viewpoint of excellent mechanical properties and moisture resistance. The thickness of the polyurethane film 42 is preferably in the range of 10 to 500 μm, more preferably in the range of 20 to 200 μm, from the viewpoint of obtaining a leather-like sheet excellent in flexibility and mechanical properties.

Then, the obtained leather-like sheet 50 is taken up by the take-up reel 14. Then, the moisture curing reaction of the first polyurethane 2 proceeds by aging for a predetermined time in the wound state.

FIG. 5 shows a schematic cross-sectional view of the leather-like sheet 50 thus obtained.

[Third Embodiment]
Next, a third embodiment will be described with reference to FIG.

In addition, since the part which attached | subjected the code | symbol similar to 1st Embodiment is a part which is common in 1st Embodiment, detailed description is abbreviate | omitted.

FIG. 6 is a schematic process diagram for explaining a method for producing a leather-like sheet according to the third embodiment. In the process of the third embodiment, in the first polyurethane layer forming process of the first embodiment, the release paper 5 is sent out instead of sending out the base cloth 1 from the delivery reel 11, and in the sheet bonding process, the release paper is released from the delivery reel 13. It is the same as that of 1st Embodiment except sending out the base fabric 1 instead of sending out 5. That is, the order of supplying the base fabric 1 and supplying the release paper 5 is simply changed.

The obtained leather-like sheet 60 has the same layer structure as the leather-like sheet 10 obtained in the first embodiment.

[Fourth Embodiment]
Next, a fourth embodiment will be described with reference to FIG. 7, FIG. 8, and FIG.

In addition, since the part which attached | subjected the code | symbol similar to 1st Embodiment is a part which is common in 1st Embodiment, detailed description is abbreviate | omitted.

FIG. 7 is a schematic process diagram for explaining a manufacturing process of the laminated intermediate 140 in the polyurethane laminate of the fourth embodiment.

In the process of the fourth embodiment, as shown in FIG. 7, a laminated intermediate 140 obtained by laminating the same porous sheet 3 as formed in the first embodiment by heating and pressing is temporarily wound by a take-up reel 74. Wind up. Then, the first hot-melt type moisture-curing polyurethane is aged and cured. The porous sheet 3 on the surface of the laminated intermediate 140 may be surface-finished or may be dry-surface-finished by a known method using an aqueous polyurethane resin.

Next, when the porous sheet 3 is a thermoplastic nonwoven fabric, after the first hot-melt type moisture-cured polyurethane is aged and cured, the surface is further smoothed by heating and pressing with a heating roll, so that the interior and the surface A sheet having fine holes and communication holes is formed.

Then, for example, as shown in FIG. 8, the second polyurethane layer is formed by spraying an aqueous polyurethane resin on the surface of the flattened porous sheet 3 with a spray coating machine 200 and drying it with a drying furnace 46. It is formed. Further, gravure coating may be used instead of spray coating. When the second polyurethane layer is formed by spray coating or gravure coating, a thin skin layer can be formed. The leather-like sheet thus obtained is particularly capable of achieving both fine creases and smoothness.

Instead of using the process shown in FIG. 8, the second hot-melt type moisture-curing polyurethane 2 was applied on the release paper 5 by the reverse roll coater 21 as shown in FIG. You may use the process of bonding with the porous sheet 3 of the lamination | stacking intermediate body 140. FIG.

As described above, an example of the manufacturing method according to the present embodiment has been exemplified as the first to fourth embodiments. However, the present invention is not limited to the above-described process. If the process is such that the effect of tackiness of moisture-cured polyurethane in an uncured state is eliminated by laminating the porous sheet after applying the moisture-cured polyurethane to the base fabric or release paper It can be used without.

The polyurethane laminate thus obtained can maintain high adhesion to the first polyurethane layer and the second polyurethane layer, particularly due to the anchor effect by the voids of the porous sheet. For this reason, in the leather-like sheet, the appearance of the crease is also improved.

The obtained leather-like sheet is further coated with a solvent-based, water-based, emulsion-based or solvent-free polyurethane resin or acrylic resin in order to impart surface designability by a known and conventional method. Alternatively, post-processing such as buffing or embossing may be appropriately performed.

The leather-like sheet thus obtained can be preferably used as a leather-like sheet that becomes a surface material for footwear, clothing, bags, furniture, and the like.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the examples.

First, the raw materials used in this example will be described together below.

<Base fabric 1,37>
Use a water-soluble thermoplastic polyvinyl alcohol-based resin as the sea component, polyethylene terephthalate with an isophthalic acid modification degree of 6 mol% as an island component, and a melt compound spinning die that has 25 islands per fiber. Used and melted and discharged from the die at 260 ° C. so that the mass ratio of sea component / island component was 30/70. The ejector pressure is adjusted so that the spinning speed is 4500 m / min, and long fibers made of ultrafine fiber generating fibers having an average fineness of 2.0 dtex are collected on a net to obtain a long fiber web having a basis weight of 30 g / m ^2. It was. The eight long fiber webs corresponding to each other were overlapped by cross wrapping to give a spinning oil. Next, needle punching at 3600 P / cm ² was performed from both sides with a needle needle, and the long fiber web was entangled. This sheet was calendered to obtain a long fiber entangled nonwoven fabric having a basis weight of 510 g / m ² and a specific gravity of 0.45. Evaphanol AP-12 (Nikka Chemical Co., Ltd.) as a water-based urethane emulsion stock solution was adjusted to 20% resin solid content and the heat-sensitive gelling agent to 15 parts with respect to the resin. After impregnating the long-fiber entangled nonwoven fabric with this emulsion, drying and curing, the water-soluble thermoplastic polyvinyl alcohol resin in the ultrafine fiber-generating fiber is dissolved and removed in warm water at 95 ° C. Thus, a base fabric 1 having a thickness of 1.0 mm in which an ultrafine fiber bundle made of an island component was expressed was obtained.

<Polyurethane nonwoven fabric 3>
A poly 3-methyl-1.5 methyl adipate glycol having an average molecular weight of 1150, 4,4-diphenylmethane diisocyanate and 1,4-butanediol are charged at a molar ratio of 1: 4: 3 and melted using a screw kneading type polymerization machine. Polyurethane was polymerized by a polymerization method. The obtained polyurethane was conveyed in the form of fine fibers with a high-speed air flow heated to a temperature of 260 ° C. from a slot at both ends of a die orifice heated at a temperature of 260 ° C. by a melt-blown method in a molten state. Random webs were collected at a collection distance of 40 cm on a wire mesh moving in minutes. By such a method, a polyurethane nonwoven fabric 3 made of fine fibers having an average diameter of 8 μm and having an average basis weight of 25 g / m ² was obtained.

<Hot melt type moisture curing polyurethane 2,312>
100 parts by weight of Task Force KMM-100 (hot melt type moisture-cure polyurethane manufactured by DIC Corporation), 15 parts by weight of pigment, and 2 parts of foaming agent are melt-mixed at 120 ° C and the melt viscosity at 125 ° C is 3000 mPa · s. A foamed hot-melt type moisture-curing polyurethane 2 was obtained.

<Hot melt type moisture curing polyurethane 4,314>
100 parts by mass of Task Force KMM-100 (hot melt type moisture-cure polyurethane manufactured by DIC Corporation) and 15 parts by mass of pigment are melt-mixed at 120 ° C., and the melt viscosity at 125 ° C. is 3000 mPa · s. A mold moisture cured polyurethane 4 was obtained.

<Water-based polyurethane adhesive 44>
An aqueous polyurethane dispersion containing hydran WLA-404 (manufactured by DIC Corporation) as a resin component and a crosslinking agent, a crosslinking accelerator, a colorant and additives.

<Polyurethane film 45 with release paper>
Aqueous polyurethane dispersion containing hydran ULK-003 (manufactured by DIC Corporation), which is an aqueous polyurethane, as a resin component, and a crosslinking agent, a crosslinking accelerator, a colorant, and additives, is used as a release paper (R manufactured by Lintec Corporation). A polyurethane film 42 having a thickness of 30 μm is formed by applying and drying on the surface of −70 N).

<Release paper 5,301>
R-70N manufactured by Lintec Corporation

[Example 1]
The leather-like sheet 10 was manufactured using the manufacturing process as shown in FIG.

Specifically, first, the base fabric 1 is sent out at a speed of 1 m / min toward the take-up reel 14 through the rollers 20, 22, 23, 24a, 24b, 25, and 27 from the delivery reel 11 to form a line. . And the hot melt type moisture hardening polyurethane 2 accommodated in the resin feeder 102 and heated and melted was flowed down in a molten state toward the base fabric 1 on the line. And the hot-melt type moisture hardening polyurethane 2 which flowed down was apply | coated to the surface of the base fabric 1 with the reverse roll coater 21 provided with the heating roll of surface temperature 110 degreeC. At this time, the coating thickness was adjusted to 200 μm.

Next, the polyurethane nonwoven fabric 3 was sent out from the delivery reel 12 toward the surface of the coating layer of the hot-melt type moisture-cured polyurethane 2 in a molten or softened state. Then, the polyurethane nonwoven fabric 3 is bonded to the surface of the coating layer of the first moisture-curing polyurethane 2 by the heating calender roll 100, and at the same time, the polyurethane nonwoven fabric 3 is heated and smoothed so that fine pores and communication hole structures are formed on the surface and inside. Been formed. At this time, the surface temperature of the heating calendar roll 100 was 155 ° C.

Next, the laminated intermediate formed by bonding the heat-smoothed polyurethane nonwoven fabric 3 is passed through rollers 23, 24 a, 24 b, and 25, and directly below the resin feeder 104 that stores the hot-melt moisture-curing polyurethane 4. It was conveyed toward the department. Then, the hot-melt type moisture-curing polyurethane 4 accommodated in the resin feeder 104 is poured into a laminated intermediate in a molten state, and is applied by a reverse roll coater 26 equipped with a heating roll having a surface temperature of 110 ° C. A polyurethane layer was formed. At this time, the coating thickness was adjusted to 40 μm.

Then, the release paper 5 was delivered from the delivery reel 13 and bonded to the applied hot-melt moisture-cure polyurethane 4 with a calendar roll 101. In this way, a leather-like sheet 10 having a layer structure as shown in FIG. 3 was formed. Then, the obtained leather-like sheet 10 was wound up by the take-up reel 14 while being covered with the release paper 5.

In the above process, the laminated intermediate was not wound around the rollers 24a and 24b, and the continuous productivity was excellent.

Then, in a wound state, the leather-like sheet 10 was aged for 35 hours under the conditions of a temperature of 40 ° C. and a relative humidity of 60%. After aging, the obtained leather-like sheet 10 was cut by a predetermined area, the release paper 5 was peeled off, and interlayer adhesion was evaluated by the following method.

(Interlayer adhesion)
A cloth hot melt tape [Trademark: Melco Tape, manufactured by Sankasei Co., Ltd.] was thermocompression bonded at 130 ° C. for 5 seconds to the surface of the second polyurethane layer 4 of the leather-like sheet 10 from which the release paper was peeled, and then 200 mm / The peel strength was measured using Tensilon (manufactured by Shimadzu Corporation) in accordance with JIS K 6854-2 at a head speed of minutes. Moreover, the position of the part which peeled at that time was confirmed.

As a result, the peel strength of the leather-like sheet 10 was 10.6 kg / 25 mm, and internal peeling occurred within one layer of the base fabric.

[Example 2]
A leather-like sheet 50 was manufactured using a manufacturing process as shown in FIG.

Specifically, first, the base cloth 1 is sent out at a speed of 1 m / min toward the take-up reel 14 through the rollers 20, 22, 23, 24a, 24b, 25, 26, 27 from the delivery reel 11, and the line is formed. Formed. And the hot melt type moisture hardening polyurethane 2 accommodated in the resin feeder 102 and heated and melted was flowed down in a molten state toward the base fabric 1 on the line. And the hot-melt type moisture hardening polyurethane 2 which flowed down was apply | coated to the surface of the base fabric 1 with the reverse roll coater 21 provided with the heating roll of surface temperature 110 degreeC. At this time, the coating thickness was adjusted to 30 μm.

Next, the polyurethane nonwoven fabric 3 is sent from the delivery reel 12 toward the surface of the molten or softened hot melt moisture-curing polyurethane 2 and is applied by the heating calendar roll 100 to the first moisture-curing polyurethane 2. At the same time as laminating to the surface of the layer, the polyurethane nonwoven fabric 3 was heated and smoothed to form micropores and communication hole structures on the surface and inside. At this time, the surface temperature of the heating calendar roll 100 was 155 ° C.

Next, the laminated intermediate formed by bonding the heat-smoothed polyurethane nonwoven fabric 3 passes through rollers 23, 24 a, 24 b, and 25, and immediately below the resin feeder 144 that contains the aqueous polyurethane adhesive 44. It was conveyed towards. Then, the aqueous polyurethane adhesive 44 accommodated in the resin feeder 144 was flowed down to the surface of the polyurethane nonwoven fabric 3 and applied to the surface of the polyurethane nonwoven fabric 3 with a uniform thickness by the knife coater 154. At this time, the coating thickness was adjusted to 50 μm. Then, an adhesive layer 47 derived from the aqueous polyurethane adhesive 44 was formed by drying with a drying furnace 46. And it was made to merge with the polyurethane film 45 with release paper sent out from the delivery reel 43, and it was bonded by the calendar roll 101 so that the adhesive layer 47 and the polyurethane film 42 on the surface of the polyurethane film 45 with release paper faced each other. Thus, the leather-like sheet | seat 50 which has a layer structure as shown in FIG. 5 was formed. The obtained leather-like sheet 50 was wound up by the take-up reel 14 while being covered with the release paper 5.

In the above process, the laminated intermediate was not wound around the roller in the process, and the continuous productivity was excellent.

Then, in a wound state, the leather-like sheet 50 was aged for 35 hours under the conditions of a temperature of 40 ° C. and a relative humidity of 60%.

After aging, the obtained leather-like sheet 50 was cut by a predetermined area, the release paper 5 was peeled off, and interlayer adhesion was evaluated by the same method as in Example 1. As a result, the peel strength of the leather-like sheet 50 was 13.3 kg / 25 mm, and internal peeling occurred within one layer of the base fabric.

[Example 3]
A polyurethane laminate was produced using the production process shown in FIGS.

Specifically, as shown in FIG. 7, a line was formed by feeding the base fabric 1 from the feed reel 11 through the roller 20 toward the take-up reel 74 at a speed of 1 m / min. And the hot melt type moisture hardening polyurethane 2 accommodated in the resin feeder 102 and heated and melted was flowed down in a molten state toward the base fabric 1 on the line. And the hot-melt type moisture hardening polyurethane 2 which flowed down was apply | coated to the surface of the base fabric 1 with the reverse roll coater 21 provided with the heating roll of surface temperature 110 degreeC. At this time, the coating thickness was adjusted to 200 μm.

Next, the polyurethane nonwoven fabric 3 is sent out from the delivery reel 12 toward the surface of the molten or softened hot-melt type moisture-curing polyurethane 2 and is applied by the calendar roll 100 to the first moisture-curing polyurethane 2 coating layer. A laminated intermediate 140 was formed by being bonded to the surface. The laminated intermediate 140 was once taken up by the take-up reel 74. Then, the wound laminated intermediate 140 was aged for 35 hours under the conditions of a temperature of 40 ° C. and a relative humidity of 60%. The surface of the polyurethane nonwoven fabric 3 of the laminated intermediate 140 after aging was smoothed by heating with a calender roll at a temperature of 155 ° C., so that the total thickness of the first polyurethane layer and the polyurethane nonwoven fabric layer was 125 μm. Micropores and communication holes were formed inside and on the surface of the heat-smoothed polyurethane nonwoven fabric 3. And as shown in FIG. 8, it sprays with the spray coating machine 200 so that aqueous polyurethane resin may be set to 15 g / m < ² > in solid content conversion as a 2nd polyurethane layer on the polyurethane nonwoven fabric 3 surface of the surface layer of the lamination | stacking intermediate body 140. FIG. The polyurethane laminate which balances a fine crease and smoothness was obtained by apply | coating, drying with the drying furnace 46, and also embossing with a heating calender roll 101 by flat plate heating embossing. The interlayer adhesion of the obtained polyurethane laminate was evaluated by the same method as in Example 1. As a result, the peel strength of the polyurethane laminate was 12.5 kg / 25 mm, and internal peeling occurred within one layer of the base fabric.

[Comparative Example 1]
Instead of using the process having the step of bonding the polyurethane nonwoven fabric 3 as shown in FIG. 2, the leather-like sheet was manufactured using the process having no step of bonding the polyurethane nonwoven fabric 3 as shown in FIG. A leather-like sheet was produced in the same manner as in Example 1 except for the above.

Specifically, as shown in FIG. 1, a release paper 301 was sent out from the delivery reel 30 toward the take-up reel 38 at a speed of 1 m / min to form a line. Then, the release paper 301 wound around the delivery reel 30 was carried on rollers 31 and 32. Then, a coating layer was formed by applying a hot-melt type moisture-curing polyurethane 312 in a molten state to the surface of the release paper 301 with a knife coater 303. At this time, the coating thickness was adjusted to 40 μm. Subsequently, water vapor was sprayed by a water vapor sprayer 304 onto the coating layer made of hot melt moisture-curing polyurethane 312. And it put on roller 33a, 33b, sent to the roller 34, and apply | coated the hot-melt type moisture hardening polyurethane 314 of the molten state with the knife coater 305. FIG. Then, the base cloth 37 was supplied from the delivery reel 36, and the base cloth 37 was bonded to the adhesive layer of the hot-melt type moisture-curing polyurethane with the roller 35 to produce a leather-like sheet.

In the above process, the laminated intermediate often wraps around the rollers 33a and 33b shown in FIG. 1 and smooth conveyance is not performed, and continuous production is difficult. The bare leather-like sheet was aged for 35 hours under conditions of a temperature of 40 ° C. and a relative humidity of 60%. Then, after aging, the obtained leather-like sheet was cut by a predetermined area, the release paper was peeled off, and the interlayer adhesion was evaluated by the same method as in Example 1. As a result, the peel strength of the leather-like sheet was 6.5 kg / 25 mm, and interface peeling occurred at the interface between the layer made of moisture-cured polyurethane 312 and the layer made of moisture-cured polyurethane 314.

[Comparative Example 2]
A leather-like sheet 80 is manufactured using a process having a step of spraying water vapor with a water vapor sprayer 304 as shown in FIG. 10 instead of using a process having a step of bonding the polyurethane nonwoven fabric 3 as shown in FIG. A leather-like sheet was produced in the same manner as in Example 2 except that.

Specifically, first, the base fabric 1 is sent out at a speed of 1 m / min toward the take-up reel 14 through the rollers 20, 23, 24a, 24b, 25, 26, and 27 from the sending reel 11 to form a line. . And the hot melt type moisture hardening polyurethane 2 accommodated in the resin feeder 102 and heated and melted was flowed down in a molten state toward the base fabric 1 on the line. And the hot-melt type moisture hardening polyurethane 2 which flowed down was apply | coated to the surface of the base fabric 1 with the reverse roll coater 21 provided with the heating roll of surface temperature 110 degreeC. At this time, the coating thickness was adjusted to 30 μm. Subsequently, water vapor was sprayed onto the film layer made of the hot-melt type moisture-curing polyurethane 2 with the water vapor sprayer 304. And it was conveyed toward the direct lower part of the resin feeder 144 which accommodates the water-based polyurethane adhesive 44 through the rollers 23, 24a, 24b, and 25. Then, the aqueous polyurethane adhesive 44 accommodated in the resin feeder 144 was flowed down to the surface of the film made of the hot-melt type moisture-curing polyurethane 2, and was applied with a uniform thickness by the knife coater 154. At this time, the coating thickness was adjusted to 50 μm. Then, an adhesive layer 47 derived from the aqueous polyurethane adhesive 44 was formed by drying with a drying furnace 46. And it was made to merge with the polyurethane film 45 with release paper sent out from the delivery reel 43, and it was bonded by the calendar roll 101 so that the adhesive layer 47 and the polyurethane film 42 on the surface of the polyurethane film 45 with release paper faced each other. In this way, a leather-like sheet 80 was formed. The obtained leather-like sheet 80 was wound up by the take-up reel 14 while being covered with the release paper 5.

In the above process, a phenomenon in which the laminated intermediate body is wound around the rollers 24a and 24b shown in FIG. 10 and the smooth conveyance is not performed frequently occurs, and continuous production is difficult. The bare leather-like sheet was aged for 35 hours under conditions of a temperature of 40 ° C. and a relative humidity of 60%. After aging, the obtained leather-like sheet 80 was cut by a predetermined area, the release paper was peeled off, and the interlayer adhesion was evaluated by the same method as in Example 1. As a result, the peel strength of the leather-like sheet was 6.5 kg / 25 mm, and interface peeling occurred at the interface between the layer made of moisture-cured polyurethane 2 and the layer made of polyurethane film 42.

As a result of the above examples, the surface of the first moisture-curing polyurethane according to the present invention is coated with a polyurethane nonwoven fabric, and then the second moisture-curing polyurethane is laminated to form a leather-like sheet. Example 1 After covering the surface of the first moisture-cured polyurethane with a polyurethane nonwoven fabric, a polyurethane film previously formed as a polyurethane film with a release paper was adhered by an adhesive layer derived from aqueous polyurethane, and a leather-like sheet In Example 2 formed, the first moisture-cured polyurethane 2 did not wrap around the roller during production, smooth conveyance was performed in the process, and the continuous productivity was excellent. In Example 3 in which the second polyurethane layer was formed by spraying an aqueous polyurethane resin after coating the surface of the first moisture-curing polyurethane with a polyurethane nonwoven fabric, by coating with a polyurethane nonwoven fabric, Since the laminated intermediate can be wound up once, the production process can be simplified. On the other hand, in Comparative Examples 1 and 2 in which the surface of the first moisture-curing polyurethane 2 was not coated with the polyurethane nonwoven fabric 3, the coating layer of the first moisture-curing polyurethane was wound around the roller during production, and the process was smooth. Therefore, continuous production was difficult.

In addition, all of the leather-like sheets obtained in Examples 1 to 3 had high peel strength in the interlaminar adhesion test, and were internally peeled with a layer made of the first moisture-cured polyurethane. On the other hand, the peel strength of the leather-like sheet obtained in the comparative example was low and peeled at the interface between the first moisture-cured polyurethane and the second moisture-cured polyurethane. This is presumably because, in Examples 1 to 3, the polyurethane nonwoven fabric has a so-called primer function that exhibits an anchoring effect on the first polyurethane layer and the second polyurethane layer.

As described above, one aspect of the present invention is that the first polyurethane layer is formed by applying the hot-melt type moisture-cured polyurethane heated and melted to the surface of the base fabric or release paper. Leather-like, comprising a step, a porous sheet laminating step of laminating a porous sheet to the first polyurethane layer, and a second polyurethane layer forming step of forming a second polyurethane layer on the outer surface of the porous sheet It is a manufacturing method of a sheet.

According to such a manufacturing method, in order to coat the surface of the hot-melt type moisture-cured polyurethane having tackiness formed as the first polyurethane layer with the porous sheet having substantially no tackiness, It is possible to suppress a decrease in productivity of the leather-like sheet due to the adverse effect of the tackiness. Moreover, since the space | gap which a porous sheet has exhibits an anchor effect, the adhesiveness of the 2nd polyurethane layer and 1st polyurethane layer to be formed can be improved. In addition, according to a porous sheet, since the channel | path of a water | moisture content can fully be ensured, the moisture sclerosis | hardenability of hot melt type moisture hardening polyurethane can fully be maintained. And the usage-amount of an organic solvent can be reduced by using a solvent-free hot-melt type moisture hardening polyurethane.

The manufacturing method further includes a sheet bonding step of bonding a sheet to the surface of the second polyurethane layer after the second polyurethane layer forming step, wherein the first polyurethane layer is based on the first polyurethane layer forming step. If it is formed on the surface of the cloth, the sheet in the sheet bonding step is a release paper, and if the first polyurethane layer is formed on the surface of the release paper, the sheet is a base cloth. It is preferable. According to this configuration, instead of using the base fabric in the first polyurethane layer forming step, the base fabric may be used in the sheet laminating step, and instead of using the release paper in the first polyurethane layer forming step. Since the release paper can be used in the sheet bonding step, the leather-like sheet can be obtained by peeling the release paper used in the first polyurethane layer forming step or the sheet bonding step in any manufacturing method. Can be completed.

Further, in the production method, the porous sheet is a polyurethane nonwoven fabric, and the porous sheet laminating step is a step of smoothing the polyurethane nonwoven fabric by heating and pressing and bonding the polyurethane nonwoven fabric to the first polyurethane layer. Preferably there is. In this way, the polyurethane nonwoven fabric is heated and pressed and bonded to the first polyurethane layer, whereby the polyurethane nonwoven fabric having many spaces is compressed into a smoothed sheet having appropriate voids. Thereby, the intensity | strength of the layer which consists of a porous sheet improves. Also, the adhesion between the first polyurethane layer and the second polyurethane layer is improved.

When the porous sheet laminating step includes the step of smoothing the surface of the polyurethane non-woven fabric by heating and pressing simultaneously with or after laminating the polyurethane non-woven fabric to the first polyurethane layer, the polyurethane non-woven fabric Is a smoother sheet, which is preferable because the strength of the layer made of the porous sheet is further improved.

Further, when the porous sheet is a foamable polyurethane sheet, it is preferable from the viewpoint that the porosity and the anchor effect can be easily adjusted because the porosity can be easily adjusted in advance.

In the manufacturing method, the porous sheet can be easily bonded to the first polyurethane layer in a molten or softened state while maintaining a high adhesive force. To preferred.

When the second polyurethane layer forming step is a step of applying hot-melt type moisture-cured polyurethane heated and melted on the outer surface of the porous sheet, the amount of organic solvent used can be further reduced. It is preferable from the point.

In the manufacturing method, the second polyurethane layer forming step may include forming a polyurethane film derived from hot-melt moisture-curing polyurethane or aqueous polyurethane previously formed on the surface of the sheet on the outer surface of the porous sheet. The sheet is a release paper if the first polyurethane layer is formed on the surface of the base fabric, and the sheet is formed if the first polyurethane layer is formed on the surface of the release paper. Is preferably a base fabric since the amount of the organic solvent used can be further reduced.

Further, in the above production method, when the first polyurethane layer or the second polyurethane layer is a foamed polyurethane layer, it is preferable because a soft leather-like sheet rich in elasticity can be obtained.

Another aspect of the present invention includes a base fabric, a first polyurethane layer formed from a hot-melt type moisture-cured polyurethane laminated on the surface of the base fabric, and a surface of the first polyurethane layer. A leather-like sheet comprising a laminated porous sheet and a second polyurethane layer laminated on the porous sheet. According to such a structure, the space | gap of the said porous sheet exhibits the anchor effect, and the adhesiveness of a porous sheet, a 1st polyurethane layer, and a 2nd polyurethane layer improves. Thereby, the peel strength and crease state of the obtained leather-like sheet are improved. Moreover, it can manufacture by reducing the usage-amount of an organic solvent.

Further, when the porous sheet is a polyurethane non-woven fabric smoothed by being heated and pressed, the adhesion with the first polyurethane layer and the second polyurethane layer, the smoothness of the leather-like sheet and the crease This is preferable in that the state is excellent.

Further, when the first polyurethane layer is a foamed polyurethane layer, it is preferable from the point that it becomes a leather-like sheet rich in elasticity.

Also, when the second polyurethane layer is formed from hot melt moisture-curing polyurethane or water-based polyurethane, it can be produced by further reducing the amount of organic solvent used.

According to the method for producing a leather-like sheet of the present invention, the surface of the hot-melt type moisture-cured polyurethane having tackiness formed as the first polyurethane layer is coated with a porous sheet having substantially no tackiness. Therefore, it is possible to suppress a decrease in the productivity of the leather-like sheet due to the adverse effect of the tackiness. Moreover, since the solventless hot-melt moisture-curing polyurethane is used, the amount of organic solvent used can be reduced. Furthermore, the obtained leather-like sheet has high adhesion between the first polyurethane layer and the second polyurethane layer due to the anchor effect of the porous sheet.

Claims (13)

A first polyurethane layer forming step of forming a first polyurethane layer by applying hot-melt type moisture-cured polyurethane heated and melted on the surface of the base fabric or release paper, and bonding a porous sheet to the first polyurethane layer A method for producing a leather-like sheet, comprising: a porous sheet laminating step; and a second polyurethane layer forming step of forming a second polyurethane layer on the outer surface of the porous sheet. Further, after the second polyurethane layer forming step, a sheet bonding step of bonding a sheet to the surface of the second polyurethane layer is provided, and if the first polyurethane layer is formed on the surface of the base fabric, the sheet is 2. The method for producing a leather-like sheet according to claim 1, wherein the sheet is a base cloth if it is a release paper and the first polyurethane layer is formed on the surface of the release paper. The porous sheet is a polyurethane nonwoven fabric, and the porous sheet laminating step is a step of smoothing and laminating the polyurethane nonwoven fabric by heating and pressing the polyurethane nonwoven fabric. Method of leather-like sheet. The porous sheet laminating step includes a step of smoothing the surface of the polyurethane non-woven fabric by heating and pressing simultaneously with or after laminating the polyurethane non-woven fabric to the first polyurethane layer. A method for producing leather-like sheets. The method for producing a leather-like sheet according to claim 1 or 2, wherein the porous sheet is a foamable polyurethane sheet. The method for producing a leather-like sheet according to any one of claims 1 to 5, wherein the porous sheet is bonded to the first polyurethane layer in a melted or softened state. The leather-like sheet according to any one of claims 1 to 6, wherein the second polyurethane layer forming step is a step of applying hot-melt type moisture-cured polyurethane heated and melted to the outer surface of the porous sheet. Manufacturing method. The second polyurethane layer forming step is a step of adhering a polyurethane film derived from hot melt moisture-curing polyurethane or aqueous polyurethane previously formed on the surface of the sheet to the outer surface of the porous sheet, 2. The sheet is a release paper if a polyurethane layer is formed on the surface of the base fabric, and the sheet is a base fabric if the first polyurethane layer is formed on the surface of the release paper. 8. The method for producing a leather-like sheet according to any one of 1 to 7. The method for producing a leather-like sheet according to any one of claims 1 to 8, wherein the first polyurethane layer or the second polyurethane layer is a foamed polyurethane layer. A base fabric, a first polyurethane layer formed from a hot-melt moisture-cured polyurethane laminated on the surface of the base fabric, a porous sheet laminated on the first polyurethane layer, and a porous sheet laminated on the porous sheet. And a second polyurethane layer. The leather-like sheet according to claim 10, wherein the porous sheet is a polyurethane nonwoven fabric smoothed by being heated and pressed. The leather-like sheet according to claim 10 or 11, wherein the first polyurethane layer is a foamed polyurethane layer. The leather-like sheet according to any one of claims 10 to 12, wherein the second polyurethane layer is formed from a hot-melt moisture-curing polyurethane or an aqueous polyurethane.

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