JP2002155474A - Mold release paper and synthetic leather produced by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce mold release paper which is used for producing a synthetic leather and can impart an appearance and a touch similar to those of a peach skin to the surface of the synthetic leather, and to provide a synthetic leather which is produced by using the mold release paper and whose surface has the appearance and the touch similar to those of the peach skin. SOLUTION: The mold release paper 10 comprising substrate paper 1 and a mold release resin layer 2 which is laminated to one side of the substrate paper 1 is characterized in that the mold release resin layer 2 is formed from polypropylene and/or a 4-methylpentene-1 based resin and has a fine uneven surface 3 which has an arithmetical average roughness Ra of 0.5 to 15 μm, an average unevenness distance Sm of 0.5 to 10 μm, and an average unevenness inclination θa of >=45 deg. and <90 deg.. The fine unevenness 3 can easily be formed by a heat press method. The mold release paper 10 can be used for producing a synthetic leather by a known paste-coating method or a dry method to provide the synthetic leather having the appearance and the touch similar to those of the peach skin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release paper and a synthetic leather produced using the same, and more particularly, to a release paper used for producing a synthetic leather, wherein the surface of a skin layer of the synthetic leather is provided. The present invention also relates to a release paper capable of providing an appearance and a tactile sensation like a so-called peach skin feeling, and a synthetic leather having a delicate peach skin-like appearance and a tactile sensation manufactured using the release paper.

[0002]

2. Description of the Related Art Conventionally manufactured synthetic leather includes:
Polyurethane leather, semi synthetic leather, vinyl chloride leather (P
VC leather). As a method for producing a polyurethane leather, for example, a paste-like polyurethane resin for a skin layer is applied on a release paper, dried and solidified, and then adhered to a base cloth with a two-component reaction type polyurethane adhesive to obtain 50%. There is a method of producing a polyurethane leather by removing the release paper after reacting for 2 to 3 days in an aging room at ~ 70 ° C.

[0003] As a method for producing a semi-synthetic leather, a paste-like polyurethane resin for a skin layer is applied on release paper, dried and solidified, and then a polyvinyl chloride foam layer is formed and adhered to a base cloth. After that, there is a method of manufacturing semi-synthetic leather by peeling off the release paper. Then, as a method of manufacturing PVC leather, a polyvinyl chloride sol is applied on release paper, heated and gelled, then a polyvinyl chloride foam layer is formed and bonded to the base cloth, and then the release paper is peeled off. P
There is a method of manufacturing VC leather.

As a release paper used in such a synthetic leather production method, for example, for the production of polyurethane leather, a base paper having a thickness of 2 mm of polypropylene as a release layer is used.
Release paper formed by laminating to about 0 to 50 μm is used. In addition, for the production of semi-synthetic leather or PVC leather, release paper formed by laminating a methylpentene resin as a release layer on a base paper to a thickness of about 20 to 50 μm, or release on a base paper Acrylic resin as layer 20 to 1 in thickness
Release paper formed by laminating about 20 μm is used. Further, a release paper obtained by laminating a silicone resin as a release layer on a base paper is also used. In addition, such release paper is subjected to various types of embossing processes as necessary, and the surface of the synthetic leather is embossed by the embossing.

[0005]

However, when synthetic leather is manufactured using the release paper as described above, even when the release resin layer of the release paper has been subjected to molding, the synthetic leather is usually used. When the release paper is peeled from the leather, the synthetic resin for the skin layer is clearly separated from the release resin layer of the release paper and peels off, so that the synthetic leather has a delicate appearance and touch such as a so-called peach skin feeling. It was difficult. The present invention has been made to solve such a problem,
The purpose is a release paper used for the production of synthetic leather, a release paper capable of imparting a so-called peach skin appearance and feel to the surface of the skin layer of the synthetic leather, and a production paper using the release paper. An object of the present invention is to provide a synthetic leather having a delicate appearance and tactile sensation of peach skin tone with high productivity.

[0006]

The above objects can be attained by the present invention described below. That is, the invention described in claim 1 is a release paper formed of a base paper and a release resin layer laminated on at least one surface of the base paper, wherein the release resin layer is made of polypropylene. And / or 4-methylpentene-1 resin, and the surface of the release resin layer is provided with fine irregularities, and the arithmetic average roughness (Ra) of the fine irregularities is 0.5 to 15 μm. The release paper is characterized in that the average interval (Sm) of the unevenness is 0.5 to 10 μm and the average inclination (θa) of the unevenness is 45 ° or more and less than 90 °.

As the 4-methylpentene-1 resin, a polymer of 4-methylpentene-1 or a copolymer of 4-methylpentene-1 and another α-olefin will be described in detail later. Alternatively, a blended resin obtained by blending an appropriate amount of a modified 4-methylpentene-1 polymer and / or a polyethylene resin, which are graft-modified with an unsaturated carboxylic acid or a derivative thereof, may be used.

In the present invention, the arithmetic average roughness (Ra) of fine irregularities provided on the surface of the release resin layer and the average interval (Sm) of irregularities are JIS B 0601-19.
94 is a value measured based on "Surface roughness-definition and display", and the measurement conditions are as follows. (Measurement conditions) Tip radius of the stylus: 5 μm Load: 4 mN Cut-off value: Select a standard value described in Table 1. Reference length: Select a standard value described in Table 2. Measuring equipment: Surface roughness measuring device Softest-201
[Mitutoyo Corporation] used.

[0009]

[Table 1]

[0010]

[Table 2]

[0011] The release resin layer of the polypropylene and /
Alternatively, a 4-methylpentene-1 resin has good releasability and heat resistance when producing synthetic leather such as PVC leather or polyurethane leather (hereinafter abbreviated as PU leather), and has a fine surface on its surface. It is also excellent in moldability when providing irregularities. Further, fine irregularities are formed on the surface of the release resin layer, and the arithmetic average roughness (Ra) is 0.5.
１５15 μm, and the average interval (Sm) of unevenness is 0.5〜１０10
μm, the average inclination (θa) of the unevenness is 45 ° or more and less than 90 °, and a synthetic resin such as a resin composition for a skin layer of a synthetic leather is provided on such a fine uneven surface. By applying the synthetic resin liquid, the synthetic resin liquid penetrates into the concave portions of the fine irregularities. Then, after forming a synthetic resin layer by forming a film by heating and drying or the like, by peeling the synthetic resin layer, the synthetic resin that has entered the concave portions of the fine irregularities has a greater strength at the time of peeling than its breaking strength. Since the resistance is increased, it is surely broken in the middle and a part thereof remains at the bottom of the concave portion.

The fractured surface of this synthetic resin has irregular and fine irregularities on both the peeled side and the remaining side. Therefore, the synthetic resin layer surface on the peeled side, that is, the skin layer resin surface of synthetic leather, Is a shape having fine irregularities as a whole, and this surface shape is a shape suitable for giving the appearance and touch of a peach skin to the surface of the synthetic leather. A peach skin feeling, that is, an appearance and a tactile sensation like peach skin are provided.
Also, on the release paper side that has been peeled, fine irregularities are provided on the entire surface, the broken synthetic resin remains at the bottom of the concave portions of the irregularities, and the fracture surface is irregular and has fine irregularities. Because it becomes a shape, by manufacturing a synthetic leather using this release paper, it is possible to form the same fine irregularities as the synthetic resin layer surface on the peeled side on the entire surface of the skin layer resin, A peach skin feeling, that is, an appearance and a touch like peach skin are provided.

Therefore, by adopting the above-described structure, it is possible to impart good releasability and heat resistance, and to give the skin layer of synthetic leather an appearance and a tactile sensation excellent in a so-called peach skin feeling. It is possible to provide a release paper with high productivity that can be repeatedly used a plurality of times.

According to a second aspect of the present invention, the fine irregularities on the surface of the release resin layer are irregularities formed by a hot press method. Become.

[0015] Polypropylene and / or
Alternatively, 4-methylpentene-1 resin has good mold release properties and heat resistance, and is a thermoplastic resin, so that fine irregularities of the above-described shape can be easily formed on the surface thereof by a hot press method. it can. The hot press method uses a mold roll and a nip roll (pressing roll) provided with irregularities for forming the fine irregularities on the surface, and heats and presses with a roll press method to release from the base paper. Method of forming fine irregularities on the surface of the release resin layer of the laminate of the conductive resin layer, flat pressing using a flat mold and a face plate provided with irregularities for forming the fine irregularities on the surface. Heat and pressurize in the method,
A method for forming fine irregularities on the surface of the release resin layer of the laminate of the base paper and the release resin layer, and the use of an extrusion coater such as a T-die to apply the fine particles to the surface of the chill roll (cooling roll). By providing a concave / convex part capable of forming various irregularities, using this as a mold, a release resin is extruded in the form of a film on the surface of the base paper, and pressed with a nip roll to form fine irregularities simultaneously with lamination. A method such as a roll press method or a method using an extrusion coater is particularly preferable because productivity can be further improved.

Therefore, by adopting the above-described configuration, in addition to the functions and effects of the invention described in the first aspect,
By making a mold for hot pressing with high precision, the process of forming the fine irregularities on the release resin layer of release paper,
Since release can be performed with stable quality and high productivity, release paper having excellent quality can be provided with high productivity.

According to a third aspect of the present invention, there is provided a method according to the first aspect, wherein the fine irregular surface on the surface of the release resin layer is coated with a synthetic resin on the irregular surface, and the synthetic resin layer formed by the coating is formed. The release paper according to claim 1 or 2, wherein a part of the applied synthetic resin is formed so as to be broken and remain on the bottom of the concave portion of the unevenness by being peeled off. Become. In the above synthetic resin, for example, an inorganic,
Organic fine particles can be used, thereby reducing the cohesive force of the synthetic resin, making it easier for the synthetic resin that has entered the concave and convex portions to be broken, and ensuring that the synthetic resin is at the bottom of the concave and concave portions. Can be left, and fine irregularities can be more easily formed on the broken surface of the broken synthetic resin.

Further, the release paper of the present invention has fine irregularities on the surface of the release resin layer, the arithmetic average roughness (Ra) of the fine irregularities is 0.5 to 15 μm, and Since the average interval (Sm) of the irregularities is 0.5 to 10 μm and the average inclination (θa) of the irregularities is 45 ° or more and less than 90 °, as described earlier, By producing synthetic leather in a normal procedure using a pattern paper, that is, a resin composition for a skin layer of a synthetic leather is coated on a release resin layer of the release paper, and heated and dried to form a skin. After forming the film of the layer, and further laminating the base cloth thereon, the release paper is peeled off, and thereby a part of the resin composition for the skin layer which has entered the concaves and convexes of the release resin layer. Is broken on the way, and a part of the skin layer resin composition remains at the bottom of the concave portion, Since the fracture surface is irregular and has a fine irregular shape, the surface of the synthetic leather is formed to have an appearance and a tactile sensation excellent in peach skin feeling,
The peeled release paper also has a resin composition for the skin layer that has been broken at the bottom of the concave portion of the fine irregularities of the release resin layer, and the fracture surface is irregular and has a fine irregular shape. Even when synthetic leather is produced by repeatedly using release paper, a synthetic leather having an excellent appearance and a tactile sensation can be produced as in the first case. However, in this case, the resin composition for the skin layer remaining in the concave portions of the fine irregularities of the release paper is not necessarily an optimal material as a component of the release paper, for example, in terms of its releasability. It is also possible to use a synthetic resin of a more suitable material.

Therefore, by adopting the above-described configuration, in addition to the effects of the invention described in claim 1 or 2, the synthetic resin is previously coated on the bottom of the concave portion of the fine irregularities of the release resin layer. Because it can be left, the selection range of the synthetic resin is expanded, and it is possible to select and leave the synthetic resin of a more suitable material such as mold releasability. Release paper that can be given a stable shape.

According to a fourth aspect of the present invention, there is provided a synthetic leather manufactured using the release paper according to any one of the first to third aspects.

[0021] By adopting such a configuration, a fine irregularity of a suitable shape formed on the surface of the release resin layer of the release paper according to any one of claims 1 to 3 is utilized. Since the skin layer of the synthetic leather can be formed, a synthetic leather having a delicate appearance and tactile sensation of peach skin can be more reliably provided with high productivity.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are schematic cross-sectional views each showing the configuration of an embodiment of the release paper of the present invention.

The release paper 10 shown in FIG. 1 has a configuration in which a release resin layer 2 is laminated on a base paper 1 and fine irregularities 3 are provided on the entire surface of the release resin layer 2. It was done. The fine irregularities 3 have an arithmetic average roughness (Ra) of the irregular surface of 0.5 to 15 μm and an average interval of irregularities (S
m) is 0.5 to 10 μm, and the average inclination (θa) of unevenness is 4
It is formed so as to be at least 5 ° and less than 90 °.

The release paper 20 shown in FIG. 2 is different from the release paper 10 shown in FIG. 1 in that the bottom of the concave portion of the fine unevenness 3 formed on the entire surface of the release resin layer 2 is further provided. ,
The surface is filled with a synthetic resin 4 having a fine uneven shape. As described above, such a synthetic resin 4 includes, as described above, a resin composition for a skin layer used for manufacturing synthetic leather such as PVC leather and PU leather, that is, a polyvinyl chloride or polyurethane containing various additives. The resin composition or the like may be used as it is, or a resin composition or the like that has reduced cohesion by adding, for example, inorganic or organic fine particles to another resin having relatively good releasability and heat resistance is used. can do.

The inorganic and organic fine particles include, for example, inorganic fine particles such as silica, calcium carbonate, talc, kaolin, clay, titanium oxide, zinc oxide, alumina, and aluminum hydroxide. As the fine particles, fine particles such as melamine resin, tetrafluoroethylene resin, silicone resin, acrylic resin, and polypropylene can be appropriately selected and used in consideration of the particle diameter. The appropriate particle size of such fine particles is about 0.1 to 2 μm.

As described above, the method of filling the synthetic resin 4 into the bottom of the concave portion of the fine unevenness 3 is such that the liquid of the resin composition is applied to the release resin layer 2 of the release paper. By coating on the top, the liquid of the resin composition also enters the concave portions having fine irregularities. Then, after the film is formed by heating and drying or the like, by peeling the film from the release paper, the resin composition that has entered the concave portions of the fine irregularities has a higher resistance to peeling than the breaking strength in the concave portions. Therefore, the resin composition is broken on the way and a part of the resin composition remains at the bottom of the concave portion. Then, the surface of the remaining resin composition, that is, the fracture surface, has a shape having irregular and fine irregularities. By leaving the resin composition, that is, the synthetic resin 4 at the bottom of the concave and convex concave portions in this manner, it is possible to fill the synthetic resin 4 having a fine concave and convex shape into the bottom of the concave concave and convex portions 3. it can.

When the resin composition for the skin layer of synthetic leather such as PVC leather or PU leather is filled in the bottom of the concave portion of the fine unevenness 3 as the synthetic resin 4, the release paper having the structure shown in FIG. The resin composition for the skin layer is coated on the mold release resin layer 2 by a usual procedure using 10 and heat-dried to form a film, and a base cloth is stuck thereon to form a synthetic leather. After the preparation, the release paper is peeled off, so that the resin composition for the skin layer automatically remains at the bottom of the concave portion of the fine unevenness 3, and the release paper 20 having the configuration shown in FIG. 2 is obtained. Therefore, it is possible to repeatedly produce a synthetic leather having a peach-skin appearance and touch by using the release paper 20 thereafter.

In the release paper of the present invention, the base paper 1
In addition to paper such as kraft paper, high quality paper, or cast coated paper, besides paper, polyethylene terephthalate, polyester such as polyethylene naphthalate,
Polyamide such as various nylons, plastic films such as polypropylene, synthetic paper, metal foil, woven fabric, non-woven fabric, and the like can be used, and these can be used alone or appropriately laminated. The laminating surface on which the release resin layer 2 is laminated on the base paper 1 is subjected, if necessary, to an easy-adhesion treatment such as corona discharge treatment, ozone treatment, and flame treatment, a primer coat, etc. And the adhesive property of the release resin layer 2 can be improved.

The release resin layer 2 may be made of polypropylene or 4-methylpentene-1 resin, or a blend resin of both. As 4-methylpentene-1 resin, 4-methylpentene-1
In addition to a single polymer, 4-methylpentene-1 and other α
-Olefin, for example, ethylene, propylene, butene-
Copolymers with α-olefins having 2 to 20 carbon atoms such as 1, hexene-1, octene-1, decene-1, tetradecene-1, and octadecene-1 can be used. In particular, 4-methylpentene- 1 is a copolymer containing 97% by weight or more and less than 98% by weight and α-olefin of 2% by weight or more and less than 3% by weight, and has a melting point of 236 ° C. to 238 ° C .;
Those having an MFR in the range of 160 to 200 g / 10 min measured under the conditions of a load of 5.0 kg and a temperature of 260 ° C. according to D1238 are preferred.

Further, with respect to 90 parts by weight of a polymer of 4-methylpentene-1 alone or a copolymer of 4-methylpentene-1 and another α-olefin, an unsaturated carboxylic acid or a derivative thereof is used. A modified 4-methylpentene-1 polymer modified by graft polymerization and / or a density of 0.910 to 0.930 g / cm ³ , DS
The melting point measured by the method C is in the range of 100 to 110 ° C., and the load is 2.16 kg according to ASTM D1238.
The MFR measured at a temperature of 190 ° C. is 1.0 to 100.
For example, a blended resin obtained by blending a polyethylene-based resin in the range of g / 10 min at a ratio of about 10 parts by weight can be suitably used. By using such a blend resin, good heat resistance and releasability can be maintained, and workability such as extrusion coating can be further improved.

Examples of the unsaturated carboxylic acid or derivative thereof used for the graft polymerization modification include maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid,
Citraconic acid, crotonic acid, isocrotonic acid, nadic acid, acrylic acid, unsaturated carboxylic acids such as methacrylic acid, or derivatives thereof, for example, acid anhydrides,
Imides, amides, esters and the like, specifically, maleic anhydride, citraconic anhydride, maleimide,
Monomethyl maleate, dimethyl maleate, glycidyl malate and the like can be mentioned. Among these, unsaturated dicarboxylic acids or anhydrides thereof are preferred, and in particular,
Maleic acid, nadic acid or anhydrides thereof are particularly preferred.

A method of laminating such a releasing resin on the base paper 1 is, for example, an extrusion coating method using a T-die or the like (both single-layer and multilayer co-extrusion are possible). A method of laminating, a method in which a release resin is formed into a film in advance, and this is bonded to the base paper 1 by a dry lamination method or the like, a method in which the release resin is made into a liquid state such as a solution or a dispersion, and a roll coating method. , Bar coating method, knife coating method, etc., to the base paper 1,
A method of forming a film and laminating the film may be employed.

The releasable resin layer 2 may be formed as a single layer using the above-described resin, but may be formed as a multilayer using, for example, a multilayer co-extrusion coating method. it can. In particular, when a 4-methylpentene-1 resin is used for the release resin layer 2, the workability of the resin is further improved by, for example, laminating in a two-layer configuration using a multilayer co-extrusion coating method. Further, by adjusting the temperature conditions during processing and the thickness of each layer, it is also possible to suppress the curl in the width direction of the release paper. Further, the formation of the fine irregularities 3 on the surface of the release resin layer 2 can be easily formed by a hot press method such as an embossing method. The contents thereof have already been described in the section of the invention described in claim 2, so that the description is omitted here.

The method for producing synthetic leather using the release papers 10 and 20 as described above is based on the method in which the surface of the release papers 10 and 20 where the fine irregularities 3 are formed on the release resin layer 2 is provided. Resin composition liquid for knife coating method, roll coating method,
After coating by gravure coating method etc., heating and drying to form a skin layer film, a two-component curing adhesive for dry lamination such as polyurethane is applied on top of it, and solvent components are dried by hot air drying etc. After removing the base cloth, the base cloth is laminated and further dried and aged, and then the release paper is peeled off to produce a synthetic leather having fine irregularities on the surface.

[0035]

The present invention will be described more specifically below with reference to examples and comparative examples. (Preparation of release paper) AKD paper (manufactured by Kishu Paper Co., Ltd.) having a tsubo of 125 g / m ² was used as a base paper, and the following two types of release resin layers were separately laminated on one surface thereof. Fine irregularities are formed on the entire surface of the release resin layer by the hot embossing method, and the arithmetic average roughness (Ra) of the irregularities and the average interval (S
m), and the average inclination (θa) of the unevenness is formed so as to be the numerical value described in the column of “surface unevenness” in Table 3, and the synthetic resin remains at the bottom of the formed unevenness concave portion. In order to carry out the treatment, the resin composition for the skin layer of PVC leather (main component polyvinyl chloride) or the resin composition for the skin layer of PU leather (polyurethane main component) is treated by the above-mentioned procedures of coating, film formation and peeling. After the operation, all of the resin compositions were allowed to remain, and release paper having the configuration described in the column of “release paper” in Examples 1 to 20 of Table 3 was obtained.

Releasable resin layer-1 TPX DX820 of 4-methylpentene-1-based resin
And DX820M (manufactured by Mitsui Chemicals, Inc.) by a co-extrusion coating method to a thickness of 15 μm and a total thickness of 3 μm.
The base paper was co-extruded and coated so as to have a thickness of 0 μm. Release resin layer-2 Polypropylene (manufactured by Chisso Corporation) was extruded and coated on a base paper so as to have a thickness of 30 μm by an extrusion coating method, and was laminated.

[0037]

[Table 3]

Apart from the above-described embodiment, as a comparative example, the shape of the fine unevenness provided on the surface of the release resin layer in the same manner as in the embodiment, that is, the arithmetic average roughness (Ra) of the uneven surface. ,
Only the average interval (Sm) of the irregularities and the average inclination (θa) of the irregularities are changed so as to be the numerical values described in the column of “Surface irregularities” of Comparative Examples 1 to 20 in Table 4, respectively.
Release papers of Comparative Examples 1 to 20 were produced. However, also in this case, since the synthetic resin is left at the bottom of the concave and convex portions formed on the surface of the release resin layer, the PV
A series of operations of coating, forming a film, and peeling the resin composition for the skin layer of C leather or the resin composition for the skin layer of PU leather were performed. The entire resin composition was peeled off cleanly by the peeling operation, and the synthetic resin could not be left at the bottom of the concave and convex concave portions. Accordingly, the configurations of the release papers of Comparative Examples 1 to 20 are as described in the column of “release paper” in Table 4.

[0039]

[Table 4]

(Preparation of Synthetic Leather) Using the release papers of Examples 1 to 20 prepared as described above and the release papers of Comparative Examples 1 to 20, PVC leather or PU leather was prepared by the following method. The quality of the peach skin feeling on the surface was determined based on the appearance and the tactile sensation, and the results are shown in Tables 3 and 4. still,
In the release papers of Examples 1 to 20, depending on the type of the resin composition left in the concave and convex portions of the surface, the one in which the PVC composition was left was used for producing PVC leather, and the polyurethane composition was used. The remaining one was used for producing PU leather. Further, in the release papers of Comparative Examples 1 to 20, since the resin composition could not be left in the concave and convex portions on the surface, one of the release papers having the same configuration was used for the production of PVC leather, and the other was used. It was decided to use it for producing PU leather.

That is, when producing PVC leather, polyvinyl chloride (molecular weight: 1000) is placed on the release resin layer.
100 parts by weight, 60 parts by weight of DOP, 5 parts by weight of a foaming agent, and 2.5 parts by weight of a stabilizer were mixed to prepare a polyvinyl chloride sol composition, which was coated by a knife coating method when dried. Is applied to be 150 g / m ² ,
After drying under the condition of 00 ° C for 2 minutes, a base cloth is stuck on it with an adhesive, dried and aged, and then the release paper is peeled off to form a PVC leather having fine irregularities on the surface. Was prepared.

When PU leather is produced, polyurethane [Resamine NE-881] is placed on the release resin layer.
1 Dainichi Seika Kogyo Co., Ltd.] 100 parts by weight, colorant [Seika Seven NET-5794 Black Dainichi Seika Kogyo Co., Ltd.] 15 parts by weight, toluene 25 parts by weight, isopropyl alcohol 25 parts by weight. P made
The polyurethane composition for U leather was coated by a knife coat method so that the coating amount at the time of drying was 150 g / m ^2.
After drying at 00 to 120 ° C. for 2 minutes, a base cloth is stuck thereon using an adhesive, dried and aged,
The release paper was peeled off to produce a PU leather having fine irregularities formed on the surface.

As is evident from the results shown in Tables 3 and 4, the release papers of Examples 1 to 20 all had an arithmetic mean roughness of the fine uneven surface formed on the surface of the release resin layer. (Ra) is 0.5 to 15 μm, the average interval (Sm) of the irregularities is 0.5 to 10 μm, and the average inclination (θa) of the irregularities is 45 ° or more and less than 90 °. Yes, when a synthetic resin, in this case, a resin composition for a skin layer of PVC leather or PU leather is applied to the surface of the release resin layer and the synthetic resin layer formed is peeled off, it enters into the concave and convex concave portions. A part of the synthetic resin layer is broken and has the ability to leave a part at the bottom of the recess, and by using the release paper to produce synthetic leather, a good peach skin feeling is obtained on the surface. It had performance that could be provided. Also,
As shown in Table 3, the synthetic leathers of Examples 1 to 20 actually manufactured using the release papers of Examples 1 to 20 all had a good peach skin-like appearance and touch. Was.

On the other hand, in the release papers of Comparative Examples 1 to 20, the arithmetic average roughness (Ra) of the fine uneven surface formed on the surface of the release resin layer and the average interval (Sm) of the unevenness were obtained. Since at least one of the average slopes (θa) of the irregularities is out of the above range, the resin composition for the skin layer of PVC leather or PU is formed on the bottom of the concave portions of the irregularities.
None of the resin compositions for the leather skin layer can remain, and therefore, the synthetic leathers manufactured using the release papers of Comparative Examples 1 to 20 all have inferior peach skin feeling on their surfaces. As shown in Table 4, the result was poor.

[0045]

As described in detail above, according to the present invention, there is provided a release paper for use in the production of synthetic leather, which has fine irregularities on the entire surface thereof, and has a surface of a skin layer of the synthetic leather, A release paper capable of providing a so-called peach skin feeling with an excellent appearance and feel, and a synthetic leather having an excellent peach skin-like appearance and feel produced using the same with good productivity. Play.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing the configuration of an embodiment of a release paper of the present invention.

FIG. 2 is a schematic cross-sectional view showing the configuration of another embodiment of the release paper of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base paper 2 Release resin layer 3 Fine unevenness 4 Synthetic resin 10, 20 Release paper

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B29K 105: 20 B29K 105: 20 B29L 7:00 B29L 7:00 9:00 9:00 31:00 31: 00 F term (reference) 4F055 AA01 DA02 DA12 FA08 FA15 GA13 4F100 AK07B AK08B BA02 DD07B DD09B DG10A GB90 4F209 AA11 AA12 AC03 AD06 AD08 AG01 AG03 AG05 AH81 PA01 PB02 PC03 PC06 PC08 PG05

Claims (4)

[Claims] 1. A release paper formed of a base paper and a release resin layer laminated on at least one surface of the base paper, wherein the release resin layer is made of polypropylene and / or 4-methyl. It is formed of a pentene-1 resin and has fine irregularities on the surface of the release resin layer, and the arithmetic average roughness (Ra) of the fine irregularities is 0.5 to 15 μm. Release paper characterized in that the average spacing (Sm) is 0.5 to 10 μm and the average inclination (θa) of the unevenness is 45 ° or more and less than 90 °. 2. The method according to claim 1, wherein the fine irregularities on the surface of the release resin layer are
2. The release paper according to claim 1, wherein the release paper has irregularities formed by a hot press method. 3. A fine uneven surface on the surface of the release resin layer is formed by applying a synthetic resin to the uneven surface and peeling off the synthetic resin layer formed by coating. The release paper according to claim 1, wherein a part of the applied synthetic resin is formed so as to be broken and remains at the bottom of the concave and convex portions. 4. A synthetic leather manufactured using the release paper according to any one of claims 1 to 3.