WO1998035884A1 - Packaging material having mold release function - Google Patents

Abstract

A packaging material which has a mold release function which enables direct packaging of various adhesive articles in a state in which the packaging material can be released from an article. The packaging material has a release function, which enables seal processing providing an adequate seal strength even if a surface being subjected to seal processing when the packaging material is subjected to seal processing is a release agent layer surface. The release agent layer surface usually develops cracks when the packaging material is drawn, and an area rate of cracks per unit surface area of the release agent layer after the packaging material is drawn is 10 to 80 % or an area rate of cracks in a seal processed portion of the packaging material is 10 % or more.

Description

 Description Packaging material with release function Technical field

 The present invention relates to a packaging material having a release function that can directly package various kinds of adhesive articles in a state where they can be peeled off from the article. The present invention relates to a packaging material having a release function that can be processed. Background art

 An adhesive is often used as a simple means for adding an adhesive function to various articles.

For example sanitary napkins (hereinafter, referred to as napkin.), In order to prevent misalignment during use, the pressure-sensitive adhesive layer is formed on the surface _(the good Una napkin typically an adhesive layer with a release paper After protection, the entire napkin is individually sealed and wrapped with a packaging material such as a plastic film, etc. In this case, the opening of the packaging material after the napkin is wrapped is made of various types such as a heat seal method and a press seal method. Sealed by sealing.

 On the other hand, recently, a method of directly packing an adhesive-coated napkin with a packaging material having a release function on the surface without protecting the adhesive layer with release paper has become mainstream. As a packaging material having a releasing function, a material in which various release agents such as silicone are applied to the surface of a base material such as a plastic film is generally used. ing.

When such a packaging material having a release function is used, a release paper for protecting the adhesive layer is not required, and therefore, dust generated when using a napkin is used. It is less economical and more economical.

 However, in the case of a packaging material having a release agent layer formed on the surface of the base material, if the packaging material is to be sealed, the processed surface is the surface coated with the release agent (release agent layer surface). Thus, it was impossible to perform a sealing process having sufficient hermeticity.

Also, in order to achieve a seal with sufficient seal retention. Apply a release agent to the base material so that it only contacts the adhesive layer, and do not apply the release agent to the sealing surface Packaging materials have also been proposed. ₍ However, such packaging materials require the release agent to be applied in a pattern, so compared to those that do not require the release agent to be applied in a pattern. There were problems such as the complexity of the manufacturing process and the high cost in terms of product yield.

 The present invention has been made in view of the above problems, and an object of the present invention is to provide a packaging material having a release function in which a release agent layer is formed on the surface of a base material, wherein the seal processing surface has a release agent. An object of the present invention is to provide a packaging material having a release function capable of performing sealing with sufficient adhesive strength even on the surface of a layer. Disclosure of the invention

 The present inventors have conducted intensive studies to solve the above problems, and as a result, formed a release material layer on the surface of a stretchable base material to produce a packaging material, and the release agent layer Cracks are formed when the material is stretched, and the above problem is solved by setting the area ratio of cracks per unit surface area of the release agent layer after the packaging material is stretched to a specific range. It has been found that the present invention can be achieved, and has led to the present invention.

That is, the present invention relates to a packaging material having a release agent layer formed on the surface of a stretchable base material, wherein the release agent layer is formed when the packaging material is stretched. It is characterized by causing cracks, and the area ratio of cracks per unit surface area of the release agent layer after the packaging material is stretched is 10 to 80% (aspect 1) ). Further, the packaging material of the present invention is characterized in that the area ratio of a crack portion per unit surface area of the release agent layer in the sealed portion is 10% or more (aspect 2). The present invention is found that, a brief description of the embodiment 1 or the packaging material having a releasing function of 2 related to that used as a separate packaging material tacky adhesive article (embodiment 3) _c drawings

Fig. 1 is a cross-sectional view showing the packaging material having the release function of the present invention. _C Fig. 2 is a scanning electron microscope showing the surface of the release agent layer after stretching the packaging material having the release function of the present invention. It is an electron micrograph (magnification: 300 times) when observed by (SEM).

 Figs. 3a and 3b are electron micrographs of the surface of the release agent layer in the sealed portion after heat sealing the packaging material having the release function of the present invention when observed by SEM. The magnifications are 100 times and 300 times, respectively.

 FIG. 4 is an enlarged cross-sectional view schematically showing the case where the packaging material having a releasing function of the present invention is used as an individual packaging material for a sanitary napkin with an adhesive. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the present invention will be described with reference to the drawings.

 FIG. 1 is a cross-sectional view showing a state of a packaging material having a release function according to the present invention (hereinafter, simply referred to as a packaging material) before a stretching treatment. A release agent layer 2 is formed on one entire surface of a substrate 1 Make up the packaging material.

In the present invention, the release agent layer formed on the surface of the substrate, immediately after the release agent is applied to the surface of the substrate and cured or dried, For example, as shown in FIG. 1, a continuous release agent film is formed on almost the entire surface of the substrate. Thereafter, by subjecting the packaging material having the above configuration to a stretching treatment, the release agent layer is cracked to be discontinuous.

 In the present invention, the cracks generated in the release agent layer when the packaging material is stretched are usually defined by a scanning electron microscope (SEM) on the surface of the release agent layer of the packaging material after stretching. It is a fine crack that can be confirmed by observing at a magnification of 0 to 1000. For example, the crack has a diameter of about 100,000 A to 6,500,000 A (angstrom) as a diameter of the crack in a direction perpendicular to the stretching direction.

 In the part where the release agent layer is cracked (cracked part), the surface of the base material that is the base is exposed, or the release agent application amount is smaller in that part compared to other parts It is formed as follows. In the packaging material of the present invention, the surface of the release agent layer can be made a sealed surface by the cracks generated in the release agent layer.

 FIG. 2 shows an electron micrograph (magnification: 300 times) of the surface of the release agent layer after the packaging material of the present invention was subjected to the stretching treatment (100% stretching) by SEM.

 In the case of the packaging material of FIG. 2, it is clear that countless cracks (P) are formed in the release agent layer in a direction substantially perpendicular to the stretching direction (S) of the packaging material.

The packaging material of the present invention requires that the release agent layer be cracked when the packaging material is stretched as described above, and furthermore, the sealability on the release agent layer surface of the packaging material and the release property. from the viewpoint of compatibility between the mold features are measured by the method described below, the area ratio is 1 ^0-8 0% of the release agent layer unit surface area equivalent Rino cracking unit after the packaging material is stretched, good or Or 30% to 70%.

If the area ratio of the cracks in the release agent layer is lower than 10%, the packaging material The sealing strength (adhesion strength) when sealing the surface of the release agent layer is insufficient, and the sealing and holding ability as a packaging material is deteriorated. Further, when the area ratio of the cracked portion is higher than 80%, the release function is reduced, and the adhesive article cannot be smoothly separated from the packaging material. In the present invention, the unit surface area of the release agent layer The area ratio of the crack is determined by analyzing the surface of the release agent after stretching the packaging material with an electron beam microanalyzer, obtaining a color mapping image, and performing image analysis processing. . When the release agent layer is composed of a silicone-based release agent, a fluorine-based release agent, and a long-chain alkyl-based release agent, the Si-α-ray, the F-α-ray, and the O- (4) The intensity of the line is measured using an electron beam microanalyzer, and the obtained color matching image is subjected to image analysis processing.

 Hereinafter, the method of measuring the area ratio of the crack portion per unit surface area of the release agent layer will be described in further detail, taking as an example the case where the release agent layer is made of a silicone-based release agent.

 1) Measure the Si-α-ray intensity on the surface of the release agent layer of the packaging material after stretching with an electron beam microanalyzer (Ε ΡΜ-810, manufactured by Shimadzu Corporation). Obtains a line intensity color mapping image.

 The analysis conditions of the electron microanalyzer are as follows: • Acceleration voltage: 15 kV, sample current: 10 nA

 • Bead scan: l O O z m X l. 40 m, beam diameter: 1 μm φ

2) The unit surface area (lOOmXlOOzm) of the obtained S i — K ct line intensity force mapping image is converted to an image processing device (Image Command 509 8 Model No. TMN- 1 5 2 8-0 1) And 3 Avionics Co., Ltd.) to perform image analysis processing and measure the area ratio of cracks. At this time, the part where S i _ 線 α-ray intensity is 40 cps or less Image analysis is performed using the part where the K α-ray intensity is higher than 40 cps as the release agent layer, and the area ratio of the crack is determined.

 The packaging material of the present invention is formed of a material that can stretch the base material itself after forming a release agent layer on the surface of the base material and then forming a crack in the release agent layer by stretching the packaging material. Need to be configured.

 The stretchable base material as referred to in the present invention has the stretchability following the stretching process for forming a crack in the release agent layer as described above, and further as a packaging material after the stretching process. The material, configuration, and the like are not particularly limited as long as they have sufficient mechanical strength.

 Further, since the packaging material of the present invention is subjected to sealing after forming a crack in the release agent layer, the base material itself has sealability by a heat sealing method, a press sealing method, or the like. Need to be.

 The base material used for the packaging material of the present invention is not particularly limited as long as it satisfies the above-mentioned characteristics. For example, the base material is mainly composed of a polyolefin-based thermoplastic resin. It is preferred that it consist of a film.

As such a polyolefin-based thermoplastic resin, for example, polyethylene, polybutene, polyhexene, polyoctene and the like can be used alone or in a mixture, and polyethylene is particularly preferably used. As the polyethylene, any of ultra-low density, low density, linear low density, medium density, high density single product or blend product can be used, and particularly preferred is linear low density polyethylene. And the content of Z or low density polyethylene is 15% by weight. /. The above, or those having a high-density polyethylene content of 80% by weight or less. If necessary, a material having a higher melting point than ultra-low-density or low-density polyethylene can be added to improve heat resistance. Such a material has a melting point of less than or equal to 185 ° C, preferably from 110 to 180 ° C. Further, for example, an elastomer component such as a styrene-based, polyolefin-based, or polyester-based polymer can be added, preferably in an amount of 40% by weight or less, to improve flexibility.

 Examples of the polymer constituting the thermoplastic film here include ultra-low density, low density, linear low density, medium density high density polyethylene, polypropylene, and ethylene vinyl acetate. Polymer, ethylene mono (meth) acrylic acid copolymer, ethylene mono

(META) Methyl acrylate copolymer, Ethylene mono (meth) Ethyl acrylate copolymer, Polyethylene propylene copolymer, Olefin-based elastomer, Styrene-based elastomer It consists of a single or a combination of two or more selected from polyisobutylene and butyl rubber.

 Here, the ethylene elastomers include ethylene-propylene rubber (EPT), ethylene-propylene-gene rubber (EPDM), ethylene-propylene and ethylene-butene elastomers such as styrene. Examples of such elastomers include styrene-isoprene-styrene block copolymer (SIS) and styrene butane-styrene block copolymer (SBS), or hydrogenation of these. Things.

 In the present invention, the base material may have a single-layer structure as described above. For example, the base material is composed of at least two or more layers, and has a melting point higher than that of one of the layers on one or both sides. It is preferable to have a heat seal layer having a temperature lower than 5 ° C because heat seal can be performed easily and reliably.

In other words, when performing heat sealing, if the heat is strong with a single layer, there is a risk that holes will be formed in the base material, making it difficult to control the material. There is an effect that the condition of the seal can be easily obtained. Examples of such a base material include a layer made of low-density polyethylene (melting point: 100 ° C.) as a heat seal layer, and a high-density polyethylene.

(Melting point: 120 ° C.) or the like having two or more layers. In this case, the release agent layer is provided on the low-density polyethylene side which is the heat seal layer.

 Further, as the substrate of the present invention, a laminate of a thermoplastic plastic film and a nonwoven fabric or a woven fabric is also preferable.

 Further, in the present invention, by blending the above polymer, the surface of the base material can be roughened like a matte surface or an embossed surface. You can get a sense of luxury. In addition, the effect that the running property of the line can be improved by reducing the dynamic friction coefficient is obtained. Due to such a blend, incompatible materials are mixed so as to be separated from each other due to a difference in interfacial tension at the time of dissolution. However, since the surface is rough, the surface is considered to be a matte or embossed surface. The roughness of this surface is usually 0.2 to 30 μπι, preferably 2 to 5 // m, but when embossing or satin is formed with It is preferable that the thickness be within 1/2 of the thickness. By blending polymers with different properties, it becomes possible to blend them with each other's strengths only, and to provide polymers with new functions, for example, functions that balance softness and good stiffness. There is an effect that can be obtained.

 Also, by blending the relatively soft polymer elastomer as described above, the peeling sound can be reduced when the packaging material is peeled off from the adhesive article, and the use is not noticed by others. There is also an effect.

A more aggressive method for forming a matte or embossed surface is- In addition to the above-described polymer blend method, the film can be formed, for example, by a knurled surface that comes into contact with a T-die extruder during the production of the film. I like it.

 Further, as the base material of the present invention, at least one side of the multilayer thermoplastic plastic film composed of at least two or more layers is made to have a matte surface or an embossed surface made of the aforementioned polymer blend. You can. By using such a multilayer structure, the characteristics of the polymer film of each layer can be compounded like a polymer blend, and new functions can be added, for example, the heat sealability and the tear strength can be improved. This has the advantage that functions can be added, such as compatibility with good texture.

 As another specific embodiment of the base material of the present invention, for example, at least one surface of a thermoplastic plastic film, for example, a matte surface having a surface roughness (R a) of about 12 or less of the film thickness. Alternatively, a release agent layer can be provided on the other surface, which is an embossed surface. This structure improves softness when touched, high-grade appearance, and improved line running performance (dynamic friction coefficient). Reduction).

 In another embodiment, at least one surface of the thermoplastic film has a matte or embossed surface having a surface roughness (Ra) of about 1 Z2 or less of the film thickness, A release agent layer may be provided on the surface.

In this case, the coefficient of static friction of the release surface or the embossed surface is preferably less than 1.5, preferably 0.2 to 1.0, and the dynamic friction coefficient was less than 1.2, preferably 0.1 to 1 0 is desirable. By setting the thickness in this range, the running performance on the line can be improved, and there is an effect that a shear, meandering, cutting, and the like hardly occur at the time of contact with the roll. The thickness of the base material is not particularly limited and is usually lmm or less, but from the viewpoint of softness and flexibility, it is 10 to 50/1 m, particularly 20 to 40 // m. I like it.

 In the present invention, a certain degree of strength is required from the viewpoint of the transfer of the base material on the line. Usually, the tensile strength of the base material in the MD direction (measuring temperature: 23 ° C) Force SSOO gf Zl O mm or more, especially 300 to 100 gf / 1 O mm, tensile strength in the TD direction of 200 gf / 1 O mm or more, particularly 300 to 100 gf / 1 O mm Is preferred. As described above, the material constituting the release agent layer in the present invention causes a crack in the release agent layer when the packaging material is stretched, and adjusts the area ratio of the cracked portion to a specific range. The material is not particularly limited as long as it can be used, and a material having a release function satisfying such characteristics can be appropriately selected and used.

 Examples of the material constituting the release agent layer include a silicone-based release agent such as a thermosetting type, an ultraviolet curing type, and an electron beam curing type, a fluorine-based release agent, or a long-chain alkyl-based release agent. (Generally, a polymer of a long-chain alkyl acrylate having 12 or more carbon atoms, a copolymer of a long-chain alkyl acrylate with another vinyl monomer, or a polyalkyl alcohol with a long-chain alkyl acrylate. A reaction product obtained by reacting a long-chain alkyl component such as (g) a known release agent that satisfies the above-mentioned properties from known release agents such as When the material is composed of a thermoplastic film, it is preferable to use a UV-curable and electron-curable silicone-based release agent which does not require heat treatment when forming the release agent layer. Especially mosquito A thione polymerization type ultraviolet curing silicone release agent is preferable.

The thickness of the release agent layer formed on the surface of the substrate is not particularly limited, but is usually 0.05 to 4 5μπι, and 0.1 to 4.0. im is preferred, and 0.3 to 1.5 / m is more preferred.

 In the present invention, the release agent can be applied to either one side or both sides of the substrate. Further, the release agent can be applied to the entire surface of the substrate or only to a part thereof.

 The method for applying the release agent to the substrate is not particularly limited, and for example, an appropriate coating apparatus such as a multi-hole method or an offset gravure method is used. can do.

 The packaging material of the present invention has a release agent layer formed by applying a release agent to the surface of the base material and performing drying or various curing treatments (for example, ultraviolet irradiation or electron beam irradiation). Thereafter, a crack is formed in the release agent layer by stretching the packaging material.

 Such a stretching treatment method is not particularly limited, and a known stretching treatment method such as a tenter stretching method and a knurl stretching method, which is used for a normal plastic film stretching treatment, is appropriately selected and used. can do.

 The stretching conditions are not particularly limited either, and the type of the base material is set so that the area ratio of the release agent layer cracks formed by the stretching process satisfies the specific range specified in the present invention. The stretching conditions can be set according to the conditions.

 As described above, the packaging material of the present invention can be stretched in advance before the sealing process. For example, after the adhesive material is packaged with the unstretched packaging material, the sealing material is stretched. Only the part can be stretched to form a crack in the release agent layer.

At this time, the area ratio of cracks per unit surface area of the release agent layer in the seal processing portion is 10% or more, and preferably 15%. / _0-95 . It must be / ₀ .

If the area ratio of the cracks per unit surface area of the release agent layer in the sealed area is lower than 10%, the adhesive strength of the sealed area is insufficient. And the hermeticity as a packaging material deteriorates.

 Here, the area ratio of the crack portion per unit surface area of the release agent layer in the seal processing portion is defined as the release agent layer surface S i Κ α line intensity of the seal processing portion under the same conditions as described above. The color matching image was obtained by image analysis under the same conditions as described above.

 When a crack is formed in the release agent layer of the seal processing portion, a stretching process for forming the crack may be performed during the sealing process. That is, the packaging material of the present invention can be used to generate a crack in the release agent layer by the external force applied to the packaging material during the sealing process.

The sealing method in this case is not particularly limited. For example, between two rolls in contact at different rotational speeds (at least one of the mouths is a heat seal). (A heating roll for heating) through the sealing part of the packaging material (the part where the packaging material overlaps), and the stretching and sealing of the packaging material can be performed simultaneously. In this case, Ri by the the child utilizing the shearing force between the rolls, _c can be generated cracks in the release agent layer of the packaging material also convex portions on the surface heater Toshiruba one obtained by forming a (projections) By using a heat sealing machine having the above, stretching of the packaging material and sealing can be performed simultaneously. In this case, at the time of the heat seal processing, a crack can be generated in the release agent layer of the packaging material by stretching the packaging material at the convex portion of the heat seal bar.

In addition to the above, if an external force for causing a crack in the release agent layer can be applied to the packaging material during the sealing process, the stretching process can be performed simultaneously with the sealing process. Therefore, in this case, it is not necessary to stretch the packaging material in advance, so It is possible to further improve the productivity of tool processing.

 Figs. 3a and 3b show electron micrographs of the packaging material of the present invention after heat sealing, peeling off the sealed part, and observing the surface of the release agent layer by SEM (Fig. 3a). : Magnification 100 ×, Figure 3b: Magnification 300 ×).

 In the case of the packaging materials shown in Figs. 3a and 3b, the packaging material undergoes the same operation as stretching when the heat sealing process is performed (the packaging material is stretched). A crack is formed.

 The packaging material of the present invention can be provided in a state where the packaging material has been stretched in advance, that is, in a state where a crack can be formed in the release agent layer and sealing can be performed, for example, as described above. Alternatively, it is also possible to provide a packaging material in a state where stretching has not been performed, and after packaging an adhesive article with such a packaging material, perform a stretching process at the time of sealing to form a crack in the release agent layer.

 FIG. 4 is an enlarged cross-sectional view schematically showing a case where the packaging material of the present invention is used as an individual packaging material (individually packed sheet) of a napkin with an adhesive. After the napkin B is packaged with the packaging material A that has not been stretched, the napkin B is stretched only in the sealing portion C, which is composed of the surfaces of the release agent layers of the packaging material, and the cracks in the release agent layer are formed. They are formed and sealed. In the drawings, reference numeral 1 denotes a substrate, 2 denotes a release agent layer, and 3 denotes an adhesive layer.

 In the present invention, the method of sealing the packaging material after the stretching treatment is not particularly limited, and for example, a heat sealing (heat bonding) method or a press sealing method can be used. . The packaging material of the present invention uses the surface of the release agent layer on which the cracks are formed as a seal processing surface.

In such cracks, the underlying base material layer is exposed, Since the amount of the release agent applied is reduced, practically sufficient seal strength (adhesion strength) can be obtained even when the surface of the release agent layer is used as a seal processing surface. In the present invention, the sealing surface of the packaging material may be formed between the surfaces of the release agent layers of the packaging material, or the surface of the release agent layer and the surface of the base material (for example, when the release agent layer is formed). May be formed on the opposite side of the surface that has been set).

In the present invention, from the viewpoint of keeping the contents tightly sealed after the sealing process, the sealing strength (measuring temperature of 23 ° C.) representing the adhesive strength of the sealing portion is 2 g Z 25 mm or more. Less than the breaking strength of the material. Preferably, the sealing strength is 5 g / 25 mm or more: 100 g g 25 mm. Here, the breaking strength of the base material refers to the strength when the base material is broken without peeling off from the sealing part when measuring the sealing strength, and refers to the state where the bonding strength of the sealing part is extremely strong. _{c If the} seal strength is less than 2 g / 25 mm, the sealed part tends to peel off easily, and the sealability of the contents tends to deteriorate.

 The packaging material of the present invention uses, in addition to the individual packaging material of the sanitary napkin with an adhesive shown in FIG. It can be used as a packaging material for direct packaging without the need.

 Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited to these examples. Reference example 1

100 parts by weight of a UV-curable silicone release agent (TPR650, manufactured by Toshiba Silicone Co., Ltd.) on the entire surface of a low-density polyethylene film with a thickness of 30 / xm. Photoinitiator (UV-9310C, manufactured by Toshiba Silicone Corporation) The mold agent was applied to a thickness of 0.7 // m, and was irradiated with UV light to form a release agent layer, thereby producing a packaging material before the stretching treatment. Reference example 2

 A release agent prepared by adding 100 parts by weight of an addition-reaction-type thermosetting silicone release agent and 2 parts by weight of a platinum-based curing catalyst to the entire surface of one side of a low-density polyethylene film with a thickness of 30 / m Was applied to a thickness of 0.3 μm, and a release agent layer was formed in a hot-air drier to prepare a packaging material before the stretching treatment. Example 1

The packaging material (25 mm width × 100 mm length) before the stretching treatment obtained in Reference Example 1 was stretched by 100 ° / _{0 with} respect to the flow direction (MD direction) of the substrate. At this time, the stretching process is performed using a tensile tester at a tensile speed of 50 mm / min.

 After the stretching treatment, the surface of the releasing agent layer was observed by SEM (magnification: 300 times). It was observed that cracks were generated in the releasing agent layer. The area ratio of the cracks per unit surface area of the agent layer was 15%. Example 2

 The packaging material (25 mm width x 100 mm length) obtained in Reference Example 1 before the stretching treatment was applied to the base material in the same direction as in Example 1 with respect to the flow direction (MD direction) of the base material. Stretched 50%.

After stretching, observed儺型agent layer surface S EM (magnification 3 0 0 times) was a roller releasing agent layer to be observed that cracking occurs a _t The release after stretching treatment agent The area ratio of the cracks per unit surface area of the layer was 50%. Example 3

 The packaging material (25 mm width x 100 mm length) obtained in Reference Example 1 before the stretching treatment was applied to the base material in the same direction as in Example 1 with respect to the flow direction (MD direction) of the base material. The film was stretched by 0%.

 After stretching, the surface of the release agent layer was observed with an SEM (magnification: 300 times). As a result, cracks were observed in the release agent layer. The area ratio of the cracks per unit surface area was 75%. Example 4

 The surface of the release agent layer of the packaging material obtained in Reference Example 1 before the stretching treatment is superimposed on the release agent layer, and is heated by a heat-sealing machine having a heat-sealing bar having convex portions on the surface. Toseal processing was performed. In the case of this embodiment, at the time of heat sealing, the packaging material is stretched at the convex portion of the heat seal bar, and the release agent layer at that portion is cracked, and sufficient sealing strength for practical use is obtained. A heat seal with was performed.

 After the heat sealing, the sealing portion of the packaging material was peeled off, and the area ratio of the crack portion per unit surface area of the release agent layer in the sealing portion of one of the packaging materials was measured. The area ratio was 53%.

Comparative Example 1

 The packaging material before the stretching treatment obtained in Reference Example 1 was used without stretching. At this time, the area ratio of the cracks per unit surface area of the release agent layer was 0%. Comparative Example 2

The packaging material before stretching (25 mm width x 100 mm length) obtained in Reference Example 1 was processed in the same manner as in Example 1 in the flow direction of the base material. (MD direction).

 After stretching, the surface of the release agent layer was observed with an SEM (magnification: 300 times). As a result, cracks were observed in the release agent layer. The area ratio of cracks per unit surface area was 5%. Comparative Example 3

 The packaging material (25 mm width x 100 mm length) obtained in Reference Example 1 before the stretching treatment was applied to the base material in the same direction as in Example 1 with respect to the flow direction (MD direction) of the base material. The film was stretched by 0%.

 After the stretching treatment, the surface of the releasing agent layer was observed by SEM (magnification: 300 times). It was observed that cracks were generated in the releasing agent layer. <Also, the releasing agent layer after the stretching treatment was observed. The area ratio of cracks per unit surface area is 85. /. Met. Comparative Example 4

 The packaging material (25 mm width x 100 mm length) obtained in Reference Example 1 before the stretching treatment was applied to the base material in the same direction as in Example 1 with respect to the flow direction (MD direction) of the base material. The film was stretched by 0%.

 After the stretching treatment, the surface of the release agent layer was observed by SEM (magnification: 300 times). No crack was found in any part of the release agent layer. Comparative Example 5

The surface of the release agent layer of the packaging material before the stretching treatment obtained in Reference Example 2 was overlapped, and heat sealing was performed in the same manner as in Example 4, but no heat sealing was performed. Was. The following evaluation was performed on the samples obtained in Examples 1 to 3 and Comparative Examples 1 to 4.

 (Heat seal strength)

 The surfaces of the release agent layers of each sample were overlapped, and heat sealing was performed using a heat sealer (TP-701S HEAT SEAL TESTER, TESTER SANGYO CO. LTD) under the following conditions. After the heat seal processing, the heat seal strength was measured at a tensile speed of 300 mm / min (T-peel test) using a tensile tester.

 The surface shape of the heat sealer of the heat sealer used in this evaluation was flat.

 • Heat seal temperature: 130 ° C

 • 2 seconds crimping time

 • Crimp conditions 4 kg / cm2

 • Crimp area 10 mm x 30 mm

 (Peeling force)

 Attach adhesive tape (trade name: F-140BK: manufactured by Nitto Denko Corporation) to the surface of the release agent layer of the sample (10 mm width) by reciprocating a 2 kg roller once, and at room temperature. After standing for 30 minutes, the peeling force when the adhesive tape was peeled from the sample (packaging material) side was measured at a tensile speed of 300 mmZmin (180 ° peeling) using a tensile tester.

Table 1 shows the results. table 1

表 1 から明らかなよ うに、 実施例 1 〜 3の包装材料は、 延伸処 理によって形成される離型剤層単位表面積当 りの亀裂部の面積率 を、 本発明において規定した特定範囲内に調整しているので、 シ —ル加工面が離型剤層表面同士であつても十分なヒ ー トシール強 度を有していると共に、 該離型剤層は粘着テープに対する剥離性 を有していることがわかる。

As is clear from Table 1, the packaging materials of Examples 1 to 3 have an area ratio of cracks per unit surface area of the release agent layer formed by the stretching treatment within a specific range defined in the present invention. Because of the adjustment, even if the sealing surface is between the release agent layer surfaces, the release agent layer has sufficient heat seal strength and the release agent layer has releasability from the adhesive tape. You can see that it is.

 On the other hand, in the packaging material of Comparative Example 3, since the area ratio of the crack portion exceeds 80% specified in the present invention, the releasability from the adhesive tape is reduced.

Further, in the packaging materials of Comparative Examples 1, 2, and 4, even if cracks were not formed in the release agent layer, or even if cracks were formed, the area ratio of the cracks was defined by the present invention as 10%. to be Ri good low, or could not heating Toshi Le processing, Ru this and force ^s I force to seal strength has become extremely rather small. Industrial applicability

The packaging material having a release function according to the present invention has the configuration as described above. By having this, even when the surface of the release agent layer is used as a seal processing surface, it is possible to perform sealing with sufficient adhesive strength, and the release agent layer has a sufficient adhesion to various adhesive articles. Peelability can be maintained.

 Therefore, by using the packaging material of the present invention, a packaging material having a release function is produced without going through a complicated manufacturing process that has been conventionally used such that a release agent is not applied only to a seal processing portion. This is possible.

 Furthermore, in the packaging material of the present invention, when the same external force as in the stretching process can be applied to the packaging material during the sealing process, the step of forming a crack in the release agent layer is performed simultaneously with the sealing process. Since it can be performed, it is not necessary to stretch the packaging material in advance, and the workability of the sealing can be further improved.

Claims

The scope of the claims 1. A packaging material having a release agent layer formed on the surface of an extensible base material, wherein the release agent layer causes a crack when the packaging material is stretched, and the packaging material is stretched. A packaging material having a release function, characterized in that the area ratio of the cracks per unit surface area of the release agent layer after the release is 10 to 80%.  2. In a packaging material in which a release agent layer is formed on the surface of a stretchable base material, the area ratio of cracks per unit surface area of the release agent layer in the sealing portion of the packaging material is 10% or more. A packaging material having a release function, characterized in that:  3. The packaging material having a release function according to claim 1 or 2, which is used as an individual packaging material for an adhesive article.  4. The packaging material having a releasing function according to claim 1 or 2, which is used as an individual packaging material for a sanitary napkin.  5. The area ratio of cracks per unit surface area of the release agent layer obtained by stretching the material in which the release agent layer is formed on the surface of the stretchable base material is 10 to A packaging material having a release function of 80%.  6. The packaging material having a mold releasing function according to claim 5, wherein the base material is a plastic film having a thickness of 10 to 50 / zm and comprising a polyolefin-based thermoplastic resin as a main component.  7. The packaging material having a release function according to claim 5, wherein the release agent layer is formed from an ultraviolet curable silicone release agent. 8. The packaging material having a release function according to claim 5, wherein the thickness of the release agent layer is 0.05 to 4.0 m.  9. The packaging material having a release function according to claim 5, wherein the release agent layer has a thickness of 0.1 to 4.0 / m.