JP2011127236A - Release sheet for artificial leather production process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a release sheet for artificial leather production process which has a proper releasability unlikely to be released during the process and to be easily released after the production process. <P>SOLUTION: The release sheet for artificial leather production process is obtained by laminating a release layer on at least one side of a substrate. The release layer is formed from a resin composition comprising an acid-modified polyolefin resin containing 1-10 mass% of an acid modifying component and 1-50 pts.mass of a crosslinking agent based on 100 pts.mass of the acid modified polyolefin resin. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a release sheet for a synthetic leather production process used in a synthetic leather production process. Specifically, the synthetic leather manufacturing process that does not easily peel off the synthetic leather resin layer in the synthetic leather manufacturing process, and can be easily peeled off without destroying the synthetic leather resin layer in the release sheet peeling process. It relates to a mold release sheet.

  Synthetic leather is industrially manufactured, is a substitute for natural leather, can be manufactured in large quantities of a certain quality compared to natural leather, and there are no restrictions on shape, clothing, It is used in a wide range of fields such as shoes, bags and sofas.

Synthetic leather manufacturing methods include a dry method and a wet method.
In the dry method, a resin solution of polyurethane or polyvinyl chloride is applied on a release sheet, heat-dried to form a resin film layer, and then a substrate such as a fabric is formed on the resin film layer via an adhesive. After joining the materials by means such as roller pressure bonding, the release sheet is peeled off to produce synthetic leather.

  In the wet method, a resin film layer is formed by coating a polyurethane or polyvinyl chloride resin solution on a release sheet and coagulating it in a coagulation tank containing dimethylformamide or the like to form a film. . Subsequently, after washing and drying, the release sheet is peeled off and further processed to produce a synthetic leather.

  As the release sheet for the synthetic leather manufacturing process used at this time, conventionally, a release sheet in which polypropylene resin is laminated on paper as a base material, or a release sheet in which silicone is laminated on paper as a base material is used. , Mainly used. In general, the release sheet is repeatedly used in the production process.

  In the case of producing synthetic leather by the above-mentioned wet method, in order to allow the resin to solidify in the coagulation liquid, or to pass the water tank for washing, However, water resistance is required. However, the paper using the base material does not have the required water resistance, and the release sheet has problems such as swelling and curling. Moreover, in the release layer used for the conventional release sheet, there is a possibility that peeling occurs between the synthetic leather resin layer and the release sheet during the process of solidifying the synthetic leather resin or washing with water. is there. In particular, in the case of a release sheet using a silicone resin, there is a tendency that peeling easily occurs. On the other hand, in order to solve the above problems, an adhesive layer is provided on the surface of the process paper, a pressure-sensitive adhesive is added to the release layer made of polypropylene resin, or a corona treatment is performed on the polypropylene resin layer. Methods for controlling the moldability have been proposed (Patent Documents 1 and 2).

JP 2003-286664 A JP 2007-154407 A

  However, when the releasability is controlled using an adhesive, the adhesive generally has a low molecular weight and insufficient solvent resistance. Therefore, when such a release sheet is used repeatedly, the releasability is reduced. The quality of the synthetic leather is likely to change before and after repeated use. Even when corona treatment is performed, the effect of the corona treatment changes with time, and when the release sheet is repeatedly used, there is a possibility that peeling occurs between the release sheet and the resin coating.

  It is an object of the present invention to provide a release sheet for a synthetic leather manufacturing process that has an appropriate releasability that is unlikely to be peeled off during the process and can be easily peeled off after the manufacturing process.

  As a result of intensive studies to solve the above problems, the present inventor has developed a resin composition containing an acid-modified polyolefin resin having an acid-modified component of 1 to 10% by mass and a crosslinking agent on at least one surface of a substrate. It has been found that a release sheet obtained by laminating a release layer formed in this manner can be suitably used as a release sheet in a synthetic leather manufacturing process, and has reached the present invention.

  The gist of the present invention is as follows.

  (1) A release sheet for a synthetic leather manufacturing process in which a release layer is laminated on at least one side of a base material, wherein the release layer is an acid-modified polyolefin resin having an acid-modified component of 1 to 10% by mass; A release sheet for a synthetic leather manufacturing process, which is formed of a resin composition containing 1 to 50 parts by mass of a crosslinking agent with respect to 100 parts by mass of the acid-modified polyolefin resin.

  (2) The resin composition for forming a release layer contains 1 to 1000 parts by mass of polyvinyl alcohol per 100 parts by mass of the acid-modified polyolefin resin. Mold sheet.

  (3) The release sheet for synthetic leather production process according to (1) or (2), wherein the base material is a resin material.

  (4) The release sheet for synthetic leather production process according to (3), wherein the base material is a polyester film.

  (5) The synthetic leather production process according to any one of (1) to (4), wherein the peel strength between the release layer and the synthetic leather resin layer is 0.1 to 3.0 N / cm Release sheet.

  (6) The release sheet for a synthetic leather production process according to any one of (1) to (5), which is usable when producing synthetic leather by a wet method.

  (7) A liquid material containing 100 parts by mass of an acid-modified polyolefin resin having 1 to 10% by mass of an acid-modified component and 1 to 50 parts by mass of a crosslinking agent is coated on a substrate and then dried. A method for producing a release sheet for a synthetic leather production process.

  According to the present invention, the release layer includes a resin composition containing an acid-modified polyolefin resin having an acid-modified component of 1 to 10% by mass and a crosslinking agent of 1 to 50 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin. To provide a release sheet for a synthetic leather manufacturing process having an appropriate releasability that can be easily peeled off after passing through a manufacturing process because it is formed of a product and hardly peels off in the process. Can do.

  The acid-modified polyolefin resin contained in the release layer needs to have an acid-modified component of 1 to 10% by mass of the acid-modified polyolefin resin. 1-7 mass% is preferable, 2-5 mass% is more preferable, and 2-3 mass% is especially preferable. When the mass ratio of the acid-modified component, that is, the modification amount is less than 1% by mass, not only sufficient adhesion to the substrate may not be obtained, but also during the synthetic leather manufacturing process, the synthetic leather resin layer There is a possibility of peeling off from the release sheet. Furthermore, at the time of producing the release sheet, it tends to be difficult to disperse the acid-modified polyolefin resin in water and laminate it on the substrate. On the other hand, when it exceeds 10 mass%, mold release property may fall.

  Examples of the acid-modifying component include an unsaturated carboxylic acid component. Examples of unsaturated carboxylic acid components include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid, and the like, as well as unsaturated dicarboxylic acid half esters and half amides. It is done. Among these, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferable from the viewpoint of dispersion stabilization of the resin, and acrylic acid, methacrylic acid, and maleic anhydride are particularly preferable.

  The olefin component which is the main component of the acid-modified polyolefin resin is not particularly limited, but an alkene having 2 to 6 carbon atoms such as ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene, 1-hexene is preferable. A mixture of these may also be used. Among these, alkene having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene and 1-butene is more preferable, ethylene and propylene are further preferable, and ethylene is most preferable.

  The acid-modified polyolefin resin preferably contains a (meth) acrylic acid ester component for the purpose of improving the adhesion to the substrate. When the (meth) acrylic acid ester component is included, the content is preferably 0.5 to 40% by mass, and in order to have good adhesion to various substrates, this range is 1 to 1%. The content is more preferably 20% by mass, and further preferably 3 to 10% by mass.

Examples of the (meth) acrylic acid ester component include an esterified product of (meth) acrylic acid and an alcohol having 1 to 30 carbon atoms. Among these, an esterified product of (meth) acrylic acid and an alcohol having 1 to 20 carbon atoms is preferable from the viewpoint of availability. Specific examples of such compounds include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, (meth) acrylic acid. Examples include octyl, decyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, and the like. Mixtures of these may be used. Of these, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl acrylate, and octyl acrylate are more preferable from the viewpoint of adhesion to the base film, and ethyl acrylate. More preferred is butyl acrylate, and particularly preferred is ethyl acrylate. ("(Meth) acrylic acid" means "acrylic acid or methacrylic acid".)
Each component constituting the acid-modified polyolefin may be copolymerized in the acid-modified polyolefin resin, and its form is not limited. Examples of the state of copolymerization include random copolymerization, block copolymerization, and graft copolymerization (graft modification).

  The melting point of the acid-modified polyolefin resin is preferably 80 to 150 ° C, more preferably 85 to 130 ° C, and further preferably 90 to 100 ° C. When the temperature exceeds 150 ° C., a high-temperature treatment is required for forming the release layer, and when the temperature is less than 80 ° C., the releasability is remarkably deteriorated.

  The Vicat softening point of the acid-modified polyolefin resin is preferably 50 to 130 ° C, more preferably 53 to 110 ° C, and still more preferably 55 to 90 ° C. When the Vicat softening point is less than 50 ° C., the releasability is lowered, and when it exceeds 130 ° C., a high temperature treatment is required for forming the release layer.

  The melt flow rate of the acid-modified polyolefin resin is preferably 1 to 1000 g / 10 minutes at 190 ° C. and 2160 g load, more preferably 1 to 500 g / 10 minutes, and 2 to 300 g / 10 minutes. Is more preferable, and 2 to 200 g / 10 min is particularly preferable. When the amount is less than 1 g / 10 minutes, it is difficult to produce a resin and to make an aqueous dispersion. On the other hand, when it exceeds 1000 g / 10 minutes, the adhesion to the substrate is lowered, and the transition to the synthetic leather resin layer as the adherend tends to occur.

  The release layer in the present invention contains a crosslinking agent. The content needs to be 1-50 mass parts with respect to 100 mass parts of acid-modified polyolefin resin. It is more preferably 3 to 30 parts by mass, and further preferably 5 to 20 parts by mass. If it is less than 1 part by mass, the effect of addition is poor, and if it exceeds 50 parts by mass, the releasability may decrease. By crosslinking the acid-modified polyolefin resin using a cross-linking agent, even when a high-temperature treatment is performed when the synthetic leather resin is cross-linked, the change in the peeling force of the release sheet is small and can be easily peeled off. Can play.

  Examples of the crosslinking agent for crosslinking the acid-modified polyolefin resin include carbodiimide compounds, oxazoline group-containing compounds, isocyanate compounds, melamine compounds, urea compounds, epoxy compounds, aziridine compounds, zirconium salt compounds, and silane coupling agents. Of these, carbodiimide compounds and oxazoline group-containing compounds are effective and preferable, and oxazoline group-containing compounds are particularly preferable.

  The oxazoline group-containing compound is not particularly limited as long as it has at least two oxazoline groups in the molecule. For example, 2,2'-bis (2-oxazoline), 2,2'-ethylene-bis (4,4'-dimethyl-2-oxazoline), 2,2'-p-phenylene-bis (2-oxazoline) , A compound having an oxazoline group such as bis (2-oxazolinylcyclohexane) sulfide, and an oxazoline group-containing polymer. These can use 1 type (s) or 2 or more types. Among these, an oxazoline group-containing polymer is preferable because of ease of handling. The oxazoline group-containing polymer is obtained by polymerizing an addition polymerizable oxazoline such as 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline. Other monomers may be copolymerized as necessary. The polymerization method of the oxazoline group-containing polymer is not particularly limited, and various known polymerization methods can be employed.

  An example of a commercially available oxazoline group-containing polymer is EPOCROSS series manufactured by Nippon Shokubai Co., Ltd. More specifically, water-soluble type “WS-500”, “WS-700”, emulsion type “K-1010E”, “K-1020E”, “K-1030E”, “K-2010E”, "K-2020E", "K-2030E", etc. are mentioned.

  The carbodiimide compound is not particularly limited as long as it has at least two carbodiimide groups in the molecule. For example, compounds having a carbodiimide group such as p-phenylene-bis (2,6-xylylcarbodiimide), tetramethylene-bis (t-butylcarbodiimide), cyclohexane-1,4-bis (methylene-t-butylcarbodiimide) And polycarbodiimide which is a polymer having a carbodiimide group. These can use 1 type (s) or 2 or more types. Among these, polycarbodiimide is preferable from the viewpoint of ease of handling. Although the manufacturing method of polycarbodiimide is not specifically limited, For example, the method of manufacturing by the condensation reaction accompanying the carbon dioxide removal of an isocyanate compound can be mentioned.

  As a commercially available product of polycarbodiimide, there is a carbodilite series manufactured by Nisshinbo. More specifically, water-soluble type “SV-02”, “V-02”, “V-02-L2”, “V-04”, emulsion type “E-” 01 ”,“ E-02 ”, organic solution type“ V-01 ”,“ V-03 ”,“ V-07 ”,“ V-09 ”, and solventless type“ V-05 ”.

  The isocyanate compound is not limited, and any of aliphatic isocyanate, alicyclic isocyanate, and aromatic isocyanate may be used. Moreover, polyfunctional liquid rubber, polyalkylene diol, etc. may be copolymerized as needed.

  The release layer in the release sheet of the present invention preferably contains polyvinyl alcohol. When it contains, the content needs to be 1-1000 mass parts with respect to 100 mass parts of acid-modified polyolefin resin. It is preferably 10 to 600 parts by mass, more preferably 20 to 400 parts by mass, and most preferably 30 to 300 parts by mass. By containing polyvinyl alcohol in this range, even when the synthetic leather resin is cross-linked, it can prevent the release layer from softening even when it is treated at high temperature, and the change in the release force of the release sheet is small. The effect that it can peel easily can be show | played. If the content is less than 1 part by mass, the effect of addition is poor, and even if it exceeds 1000 parts by mass, the effect of addition is poor. Moreover, when it exceeds 1000 parts by mass, the synthetic leather resin layer and the release layer are in close contact with each other, and not only the releasability is not obtained but also the liquid stability is lowered when used as a liquid material. There is.

  The kind of polyvinyl alcohol is not particularly limited. For example, a completely or partially saponified polymer of vinyl ester can be mentioned. Examples of the saponification method include known alkali saponification methods and acid saponification methods. Of these, a method of alcoholysis using an alkali hydroxide in methanol is preferred. As will be described later, it is preferable to have water solubility for use as a liquid material.

  Examples of vinyl esters include vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl versatate, and the like. Of these, vinyl acetate is most preferred industrially.

  It is also possible to copolymerize other vinyl compounds with the vinyl ester as long as the effects of the present invention are not impaired. Other vinyl monomers include unsaturated monocarboxylic acids such as crotonic acid, acrylic acid and methacrylic acid and their esters, salts, anhydrides, amides and nitriles; unsaturated dicarboxylic acids such as maleic acid, itaconic acid and fumaric acid. Examples include acids and salts thereof; α-olefins having 2 to 30 carbon atoms; alkyl vinyl ethers; vinyl pyrrolidones.

  The average degree of polymerization of polyvinyl alcohol is not particularly limited, but is preferably 300 to 2,000.

  Examples of commercially available polyvinyl alcohol include “JC-05”, “VC-10”, “ASC-05X”, “UMR-10HH” of “J-Poval” of Nippon Vine Poval Co .; , “PVA-103”, “PVA-105”, “Exeval” “AQ4104”, “HR3010”; Denki Poval “PC-1000”, “PC-2000”, etc. .

  Since the release sheet of the present invention has a release layer having the above-described configuration, it exhibits good adhesion to various substrates. Furthermore, it has moderate releasability with respect to the resin film of synthetic leather. Therefore, by using the release sheet of the present invention, in the synthetic leather manufacturing process, the release sheet and the synthetic leather are sufficiently adhered, and in the peeling process, it is good between the resin film of the synthetic leather and the release layer. Releasability can be expressed.

  Examples of the base material of the release sheet include resin material, paper, synthetic paper, cloth, metal material, and glass material. Although the thickness of a base material is not specifically limited, Usually, it may be 1-1000 micrometers, 1-500 micrometers is preferable, 20-300 micrometers is more preferable, and 50-200 micrometers is especially preferable.

  Examples of resin materials that can be used for the substrate include thermoplastic resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polylactic acid (PLA), and the like; polystyrene resins; nylon 6, poly-m Polyamide resins such as xylylene adipamide (MXD6 nylon); polycarbonate resins; polyacrylonitrile resins; polyimide resins; multilayers of these resins (for example, nylon 6 / MXD / nylon 6, nylon 6 / ethylene-vinyl) Examples thereof include alcohol copolymers / nylon 6) and mixtures. The base material preferably has a melting point higher than the crosslinking temperature of the synthetic leather resin. Among these, a polyester resin is preferable, and a polyethylene terephthalate resin that is relatively inexpensive and excellent in heat resistance and dimensional stability is more preferable. The resin material may be stretched.

  The resin material may contain known additives and stabilizers such as antistatic agents, plasticizers, lubricants, antioxidants, etc., and in order to improve the adhesion to the release layer, The treatment may be subjected to corona treatment, plasma treatment, ozone treatment, chemical treatment, solvent treatment and the like. Moreover, silica, alumina, etc. may be vapor-deposited, and other layers, such as a barrier layer, an easily bonding layer, an antistatic layer, an ultraviolet absorption layer, and an adhesive layer, may be laminated.

Examples of paper that can be used for the substrate include Japanese paper, craft paper, liner paper, art paper, coated paper, carton paper, glassine paper, semi-glassine paper, and the like.
The structure of the synthetic paper that can be used for the substrate is not particularly limited, and may be, for example, a single layer structure or a multilayer structure. As a multilayer structure, for example, a two-layer structure of a base material layer and a surface layer, a three-layer structure in which a surface layer exists on the front and back surfaces of the base material layer, and another resin film layer exists between the base material layer and the surface layer. A multilayer structure can be exemplified. Each layer may or may not contain an inorganic or organic filler. A microporous synthetic paper having a large number of fine voids can also be used.

  Examples of the fabric that can be used for the substrate include non-woven fabrics, woven fabrics, and knitted fabrics made of the above-described synthetic resin and natural fibers such as cotton, silk, and hemp.

  Examples of the metal material that can be used for the substrate include metal foils such as aluminum foil and copper foil, and metal plates such as aluminum plate and copper plate. Examples of the glass material include a glass plate and a cloth made of glass fiber.

  The base material using the resin material may be a paper, synthetic paper, cloth, other resin material, metal material, or the like laminated on the side opposite to the release layer in the base material. .

  The release sheet of the present invention is a release sheet for the purpose of preventing blocking between the opposite surface of the release sheet and the synthetic leather when the laminate of the release sheet and the synthetic leather is rolled. A process for forming a similar release layer may be performed on the surface opposite to the release layer. In other words, the base material may be sandwiched between a pair of release layers.

  In the present invention, the surface roughness (properties) of the substrate is not particularly limited. However, when it is desired to give a special shape to the surface of the synthetic leather, it is desirable to give a special shape to the surface of the release sheet correspondingly. The method for controlling the surface roughness is not particularly limited. For example, as a method for controlling the surface roughness of the polyester film, for example, a film is formed using a polyester resin raw material to which several mass% of inorganic particles or organic particles are added. Method (kneading mat), method of spraying fine inorganic sand on the surface to roughen the surface (sand mat), method of chemically eroding the polyester film surface with chemical solution (chemical mat), base material The method of embossing on the surface by pressing on an embossing roll etc. is mentioned. A special shape can be imparted to the surface of the synthetic leather by forming a release layer on the substrate having such a controlled surface roughness. Moreover, when forming a release layer on the substrate surface, a method (coat mat) for controlling the surface shape by adding inorganic particles or organic particles to the release layer may be used.

  The control of the surface roughness is for the purpose of preventing blocking between the reverse side surface of the release sheet and the synthetic leather resin layer when the laminate of the release sheet and synthetic leather is rolled. Further, it may be applied to the surface opposite to the side on which the release layer is provided in the substrate.

  The thickness of the release layer in the release sheet is preferably in the range of 0.01 to 5 μm, more preferably 0.1 to 2 μm, still more preferably 0.2 to 1 μm. A thickness of 3 to 0.7 μm is particularly preferable. When the thickness is less than 0.01 μm, sufficient releasability may not be obtained. When the thickness exceeds 5 μm, not only the cost is increased, but the releasability may be lowered.

  The release sheet of the present invention is easily obtained industrially by a production method in which a liquid material containing an acid-modified polyolefin resin, a cross-linking agent and, if necessary, polyvinyl alcohol is coated on a substrate and then dried. be able to.

  The method for producing a liquid material containing an acid-modified polyolefin resin, a crosslinking agent and, if necessary, polyvinyl alcohol is not particularly limited as long as each component is uniformly mixed in a liquid medium. For example, the following method is mentioned.

  (A): A method of adding and mixing a dispersion or solution of a crosslinking agent and a dispersion or solution of polyvinyl alcohol used as necessary to a dispersion or solution of an acid-modified polyolefin resin.

(B): A method of liquefying a mixture of an acid-modified polyolefin resin, a crosslinking agent, and polyvinyl alcohol used as necessary.
In the case of the method (A), a dispersion or a solution may be mixed as appropriate. The solute concentration of the dispersion or solution of polyvinyl alcohol is not particularly limited, but is preferably 5 to 10% by mass from the viewpoint of ease of handling. In the case of the method (B), when the acid-modified polyolefin resin is liquefied, a crosslinking agent and polyvinyl alcohol used as necessary may be added.

  Moreover, also when adding another component, this can be added in the arbitrary steps in the manufacturing method of (A) or (B).

  In the production of the release sheet of the present invention, the solvent in the liquid material containing the acid-modified polyolefin resin, the cross-linking agent, and polyvinyl alcohol used as necessary can be applied to the substrate, It can be used without being particularly limited. Examples thereof include water, an organic solvent, or an aqueous medium containing water and an amphiphilic organic solvent. Especially, it is preferable to use water or an aqueous medium from an environmental viewpoint and the solubility viewpoint of polyvinyl alcohol.

  Examples of organic solvents include diethyl ketone (3-pentanone), methyl propyl ketone (2-pentanone), methyl isobutyl ketone (4-methyl-2-pentanone), 2-hexanone, 5-methyl-2-hexanone, and 2-to. Ketones such as butanone, 3-heptanone, 4-heptanone, cyclopentanone, cyclohexanone; aromatic hydrocarbons such as toluene, xylene, benzene, Solvesso 100, Solvesso 150; butane, pentane, hexane, cyclohexane, heptane Aliphatic hydrocarbons such as octane, nonane; methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, chlorobenzene, o-dichlorobenzene, m-dichlorobenzene, Halogen-containing compounds such as p-dichlorobenzene; acetic acid Esters such as til, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, 3-methoxybutyl acetate, methyl propionate, ethyl propionate, diethyl carbonate, γ-butyrolactone, isophorone; Examples include amphiphilic organic solvents described below.

  Here, the aqueous medium containing water and an amphiphilic organic solvent means a solvent having a water content of 2% by mass or more. The amphiphilic organic solvent herein refers to an organic solvent having a water solubility of 5% by mass or more at 20 ° C. [For the solubility of water in an organic solvent at 20 ° C., for example, “Solvent Handbook” (It is described in documents such as Kodansha Scientific, 1990, 10th edition)]. Specifically, alcohols such as methanol, ethanol, n-propanol and isopropanol; ethers such as tetrahydrofuran, 1,4-dioxane and ethylene glycol-n-butyl ether; ketones such as acetone and methyl ethyl ketone; methyl acetate and acetic acid -Esters such as n-propyl, isopropyl acetate, methyl propionate, ethyl propionate, dimethyl carbonate; in addition, ammonia, diethylamine, triethylamine, diethanolamine, triethanolamine, N, N-dimethylethanolamine, N, N -Organic amine compounds such as diethylethanolamine and N-diethanolamine; lactams such as 2-pyrrolidone and N-methyl-2-pyrrolidone.

  The method for dispersing the acid-modified polyolefin resin in the aqueous medium as described above is not particularly limited. For example, what was described in the international publication WO02 / 055598 pamphlet is mentioned.

  The dispersed particle size of the acid-modified polyolefin resin in an aqueous medium containing water and an amphiphilic organic solvent has a number average particle size from the viewpoint of stability when mixed with other components and storage stability after mixing. It is preferably 1 μm or less, and more preferably 0.8 μm or less. Such a particle size can be achieved by the production method described in the pamphlet of International Publication No. WO02 / 055598.

  The solid content of the liquid can be appropriately selected depending on the lamination conditions, the thickness and performance of the target release layer, and is not particularly limited. However, in order to keep the viscosity of the liquid material moderate and to form a good release layer, the content is preferably 1 to 60% by mass, and more preferably 5 to 30% by mass.

  When coating a liquid material on a substrate, known methods such as gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, dip coating, brushing method After applying uniformly on the surface of the substrate by setting, etc., if necessary, set it near room temperature, and then subjecting it to a release layer or heat treatment for drying, forming a uniform release layer in close contact with the substrate can do.

  As a method for producing synthetic leather using the release sheet of the present invention, a known method can be used. General methods for producing synthetic leather include a dry method and a wet method.

  For example, when producing polyurethane leather by a dry method, a paste-like polyurethane resin solution is applied onto a release sheet, dried and solidified at 110 to 140 ° C., and then bonded to a base fabric with an adhesive. After reacting in an aging room at ˜70 ° C. for 2 to 3 days, the release sheet is peeled off to obtain polyurethane leather. As a method for producing polyvinyl chloride leather, a paste-like vinyl chloride sol is applied onto a release sheet, heated and gelled, and then a polyvinyl chloride sol containing a foaming agent is further applied and heated to foam. A method of forming a layer, laminating with a base fabric, peeling off the release sheet to obtain a polyvinyl chloride leather can be mentioned.

  In the case of producing by a wet method, a polyurethane resin solution such as N, N-dimethylformamide (DMF) solution of polyurethane resin is applied on a release sheet and controlled to a predetermined thickness using a knife coater. After the base fabric is bonded onto the coated resin solution, it is immersed in a coagulation tank in which a coagulation liquid mainly composed of water is stored. Thereby, the DMF is extracted with water to solidify the polyurethane resin, and then the DMF is completely removed in the water washing tank. Therefore, the release sheet is peeled off and dried. Thereafter, post-processing such as printing or laminating with a pattern or hue may be performed as necessary.

  Similarly, when polyurethane leather is produced by a wet method, when using a conventional release sheet laminated with polypropylene or silicone resin on paper, the adhesion between the polyurethane resin layer and the release layer is not sufficient. In the process, peeling is likely to occur, and the paper as the base material absorbs water, resulting in swelling and the quality is not constant, and it is difficult to repeatedly use the release sheet. On the other hand, when the release sheet of the present invention is used, since it has sufficient adhesion between the polyurethane resin layer and the release layer, it is difficult to peel off during the process and can be easily peeled off. . Further, when a resin material such as a polyester film is used as the base material, it can be used repeatedly.

  In the resin solution, additives such as a plasticizer, a foaming agent, a stabilizer, and a coloring agent may be added as necessary.

  In the above production method, a known method such as a roll coater, a knife coater, a reverse coater, or a curtain coater can be used as a method for coating the resin solution on the release sheet.

  Although it does not specifically limit as a base fabric for synthetic leather, For example, a nonwoven fabric, woven fabrics, such as a tricot and a Ben nylon tricot, etc. can be used.

  The synthetic leather may be subjected to a treatment such as embossing with an embossing roll or the like, if necessary, after peeling off the release sheet.

  The peel strength between the release layer of the release sheet and the surface resin layer of the synthetic leather is such that when the release sheet is held and peeled from the synthetic leather, the T-type peeling and pulling are performed at a temperature of 20 ° C. It is preferable that the average value when measured at a speed of 300 mm / min and the peel strength is stable is 0.1 to 3.0 N / cm. More preferably, it is 0.1-2.0 N / cm, More preferably, it is 0.2-1.5 N / cm, Most preferably, it is 0.2-1.0 N / cm. When the peel strength is in the above range, it is difficult for floating and peeling to occur in the synthetic leather manufacturing process, and the yield of the product can be improved and the quality can be kept high. Furthermore, when the release sheet is peeled off, it can be peeled off from the synthetic leather surface without any adverse effects. When the peel strength is less than 0.1 N / cm, the adhesion between the release sheet and the synthetic leather is poor, and thus the peel sheet is easily peeled off during the manufacturing process, possibly leading to deterioration in yield and quality. There is. Moreover, when it exceeds 3.0 N / cm, a release sheet is hard to peel off from a synthetic leather, and when peeling, the surface of a synthetic leather resin layer may be damaged.

  The release sheet for the production process of synthetic leather is often used repeatedly, but even when used repeatedly, the peel strength is preferably in the above range.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by these.
Various characteristics in the following examples and comparative examples were measured or evaluated by the following methods.

(1) Configuration of acid-modified polyolefin resin The configuration of the acid-modified polyolefin resin was determined by ¹ H-NMR analysis using a high-resolution nuclear magnetic resonance apparatus (manufactured by Varian, trade name “GEMINI 2000/300”). .

The analysis conditions are shown below.
Frequency: 300MHz
Solvent: orthodichlorobenzene (d ₄ )
Temperature: 120 ° C

(2) Organic solvent content of acid-modified polyolefin resin dispersion (% by mass)
Using an FID detector (manufactured by Shimadzu Corporation, trade name “Gas Chromatograph GC-8A”), an acid-modified polyolefin resin dispersion or an acid-modified polyolefin resin dispersion diluted with water was directly put into the apparatus, The content of the organic solvent was determined. The detection limit was 0.01% by mass.

The measurement conditions are shown below.
Carrier gas: nitrogen Column filler: GL Sciences, trade name "PEG-HT (5%)-Uniport HP (60/80 mesh)"
Column size: 3mm diameter x 3m
Sample charging temperature (injection temperature): 150 ° C
Column temperature: 60 ° C
Internal standard: n-butanol

(3) Solid content concentration (mass%) of acid-modified polyolefin resin dispersion
An appropriate amount (for example, 5 g) of the acid-modified polyolefin resin dispersion was weighed, and this was heated at 150 ° C. until the mass of the residue (solid content) became a constant amount (that is, an amount in which the residue did not decrease any more). And solid content concentration was computed according to the following formula | equation.
Solid content concentration (mass%) = mass after heating / mass before heating × 100

(4) Thickness of release layer The thickness of the substrate was measured with a contact-type film thickness meter (manufactured by HEIDENNHAIN, trade name “MT12B”). Subsequently, the release layer-forming liquid material was applied to the substrate and dried to laminate the release layer. The thickness of the obtained laminate was measured with a contact-type film thickness meter, and the thickness of the release layer was determined by subtracting the thickness before coating the release layer from the thickness of the laminate.

(5) Floating / peeling of release sheet and synthetic leather resin layer, release property Urethane resin solution on the release sheet [Crisbon “7367SL” manufactured by Dainippon Ink & Chemicals, Inc. 22 mass% N, N-dimethylformamide ( DMF) / methyl ethyl ketone (MEK) solution] was applied with a film applicator and immersed in a coagulation tank adjusted with water so that the DMF concentration was 15% by mass to coagulate the urethane resin, The presence or absence of lifting / peeling of the urethane resin layer was visually evaluated according to the following evaluation criteria. Further, a laminate of the release sheet and polyurethane cut into a size of 2 cm in width and 10 cm in length is used as a sample, and this sample is subjected to a tensile tester (manufactured by Intesco, precision universal material tester, type 2020). The peel strength was measured under the conditions of an atmospheric temperature of 20 ° C., T-peel peeling, and a pulling speed of 300 mm / min to evaluate the release property. The measurement results are shown in units of N / cm.

○: The urethane resin layer does not float or peel off from the release sheet.
X: The urethane resin layer floats off from the release sheet, is peeled off, or is completely peeled off.

(6) Repetitive usability In (5) above, the release sheet is peeled from the obtained laminate, and the release sheet after peeling is used to total the creation of the laminate in the same manner as (5). Repeated 5 times, the laminate obtained by making 5 times was cut into a size of 2 cm in width and 10 cm in length, and the peel strength was measured by the same method to evaluate the releasability.

Preparation Example 1 (Preparation of acid-modified polyolefin resin P-1)
280 g of propylene-butene-ethylene terpolymer (manufactured by Huls Japan, trade name “Best Plast 708”, propylene / butene / ethylene = 64.8 / 23.9 / 11.3 mass%) The flask was put in and melted by heating in a nitrogen atmosphere. Next, while maintaining the system temperature at 170 ° C. and stirring, 32.0 g of maleic anhydride as an unsaturated carboxylic acid and 6.0 g of dicumyl peroxide as a radical generator were added over 1 hour, respectively, and then stirred. The reaction was carried out for 1 hour. After completion of the reaction, the obtained reaction product was put into a large amount of acetone to precipitate an acid-modified polyolefin resin. This acid-modified polyolefin resin was further washed several times with acetone to remove unreacted maleic anhydride, and then dried under reduced pressure in a vacuum dryer to obtain acid-modified polyolefin resin P-1.

Preparation Example 2 (Preparation of acid-modified polyolefin resin P-2)
A propylene-butene-ethylene terpolymer (manufactured by Huls Japan, trade name “Best Plast 408”, propylene / butene / ethylene = 12.3 / 82.2 / 5.5% by mass) was used. Otherwise in the same manner as in Preparation Example 1, polyolefin resin P-2 was obtained.

Preparation Example 3 (Preparation of acid-modified polyolefin resin P-3)
280 g of a propylene-ethylene copolymer (propylene / ethylene = 81.8 / 18.2% by mass, weight average molecular weight 85,000) was heated and melted in a four-necked flask under a nitrogen atmosphere. Next, while stirring the system temperature at 180 ° C., 35.0 g of maleic anhydride as an unsaturated carboxylic acid and 6.0 g of di-tert-butyl peroxide as a radical generator were added over 2 hours, respectively. Thereafter, the reaction was allowed to proceed for 1 hour. After completion of the reaction, the obtained reaction product was put into a large amount of acetone to precipitate a resin. This resin was further washed several times with acetone to remove unreacted maleic anhydride and then dried under reduced pressure in a vacuum dryer to obtain polyolefin resin P-3.

  Table 1 shows the characteristics of the resins of Preparation Examples 1 to 3 and other acid-modified polyolefin resins used in the following Examples and Comparative Examples.

Preparation Example 4 (Preparation of acid-modified polyolefin resin aqueous dispersion E-1)
In a sealed 1 liter glass container with a heater, 60.0 g of acid-modified polyolefin resin (P-1), 45.0 g of ethylene glycol-n-butyl ether (manufactured by Wako Pure Chemical Industries, special grade, boiling point 171 ° C., Hereafter referred to as “Bu-EG”), 6.9 g of N, N-dimethylethanolamine (manufactured by Wako Pure Chemical Industries, special grade, boiling point 134 ° C., based on the carboxyl group of the maleic anhydride unit in the resin) 1.08.1 equivalents, hereinafter may be referred to as “DMEA”) 188.1 g of distilled water was injected, and the stirring blade provided in the vessel was stirred at a rotational speed of 300 rpm. During stirring, no resin precipitation was observed at the bottom of the container, confirming that it was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was kept at 140 ° C. and further stirred for 60 minutes. Then, while stirring at a rotational speed of 300 rpm, it was cooled to room temperature (25 ° C.) by air cooling, and pressure filtered (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter: 0.035 mm, plain weave). A milky yellow uniform acid-modified polyolefin resin dispersion E-1 was obtained. There was almost no residual resin on the filter.

Preparation Example 5 (Preparation of acid-modified polyolefin resin dispersion E-2)
Instead of the acid-modified polyolefin resin (P-1) in Preparation Example 4, an acid-modified polyolefin resin (P-2) was used. Otherwise by performing the same operations as in Preparation Example 4, an acid-modified polyolefin resin aqueous dispersion E-2 was obtained.

Preparation Example 6 (Preparation of acid-modified polyolefin resin aqueous dispersion E-3)
Instead of the acid-modified polyolefin resin (P-1) in Preparation Example 4, an acid-modified polyolefin resin (P-3) was used. Otherwise by performing the same operations as in Preparation Example 4, an acid-modified polyolefin resin aqueous dispersion E-3 was obtained.

Preparation Example 7 (Preparation of acid-modified polyolefin resin dispersion E-4)
A hermetic pressure resistant 1 liter glass container with a heater was prepared. In this container, 60.0 g of maleic anhydride-modified polyolefin resin (manufactured by Arkema, trade name “Bondaine LX-4110”), 90.0 g of isopropanol (manufactured by Wako Pure Chemical Industries, Ltd., hereinafter referred to as “IPA”) ), 3.0 g of triethylamine (manufactured by Wako Pure Chemical Industries, Ltd., hereinafter sometimes referred to as “TEA”), and 147.0 g of distilled water are injected, and the rotation speed of the stirring blade provided in the container is set to 300 rpm. Stir. During stirring, no resin precipitation was observed at the bottom of the container, confirming that it was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was kept at 140 to 145 ° C. and further stirred for 30 minutes. Thereafter, it was placed in a water bath and cooled to room temperature (about 25 ° C.) while stirring at a rotational speed of 300 rpm. Furthermore, pressure filtration (air pressure 0.2 MPa) was performed through a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to obtain a milky white uniform acid-modified polyolefin resin dispersion E-4. There was almost no residual resin on the filter.

Preparation Example 8 (Preparation of acid-modified polyolefin resin aqueous dispersion E-5)
Instead of the acid-modified polyolefin resin “LX-4110” in Preparation Example 7, an acid-modified polyolefin resin “Bondaine HX-8210” (manufactured by Arkema) was used. Otherwise by performing the same operations as in Preparation Example 7, acid-modified polyolefin resin aqueous dispersion E-5 was obtained.

Preparation Example 9 (Preparation of acid-modified polyolefin resin aqueous dispersion E-6)
Using a stirrer equipped with a heat-resistant 1-liter glass container with a heater, 60.0 g of “Primacol 5980I” (manufactured by Dow Chemical Co., acrylic acid-modified polyolefin resin), 16.8 g of TEA, and 223. 2 g of distilled water was charged into a glass container. And it stirred for 30 minutes, setting the rotational speed of a stirring blade to 300 rpm, maintaining system temperature at 140-145 degreeC. Then, it put on the water bath and cooled to room temperature (about 25 degreeC), stirring with a rotational speed of 300 rpm. Furthermore, pressure filtration (air pressure 0.2 MPa) was performed with a 300-mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to obtain a slightly cloudy aqueous dispersion E-6. At this time, almost no resin remained on the filter.

  Table 2 shows the compositions of the acid-modified polyolefin resin aqueous dispersions E-1 to E-6 obtained in Preparation Examples 4 to 9 and the particle diameters of the resins.

Example 1
On the corona-treated surface of a biaxially stretched polyester film (Embret S-125, thickness 125 μm, hereinafter sometimes referred to as “S-125”) as a base material, an acid-modified polyolefin resin aqueous dispersion E-1 and An aqueous solution of an oxazoline compound (Epocross WS-500 manufactured by Nippon Shokubai Co., Ltd., solid content concentration of 40% by mass, hereinafter may be referred to as “OX”) and an oxazoline compound solid content with respect to 100 parts by mass of acid-modified polyolefin resin. The liquid material added to 10 parts by mass was coated using a Meyer bar and dried at 120 ° C. for 30 seconds to form a release layer having a thickness of 0.3 μm. Then, the release sheet was obtained by performing aging at 50 degreeC for 2 days.

Example 2
Instead of the acid-modified polyolefin resin aqueous dispersion E-1 in Example 1, an acid-modified polyolefin resin aqueous dispersion E-2 was used. Otherwise, the same operation as in Example 1 was performed to obtain a release sheet.

Example 3
Instead of the acid-modified polyolefin resin aqueous dispersion E-1 in Example 1, an acid-modified polyolefin resin aqueous dispersion E-3 was used. Otherwise, the same operation as in Example 1 was performed to obtain a release sheet.

Example 4
Instead of the acid-modified polyolefin resin aqueous dispersion E-1 in Example 1, an acid-modified polyolefin resin aqueous dispersion E-4 was used. Moreover, it changed so that an oxazoline compound solid content might be 5 mass parts with respect to 100 mass parts of acid-modified polyolefin resin solid content. Otherwise, the same operation as in Example 1 was performed to obtain a release sheet.

Example 5
Instead of the acid-modified polyolefin resin aqueous dispersion E-4 in Example 4, an acid-modified polyolefin resin aqueous dispersion E-5 was used. Otherwise by performing the same operations as in Example 4, a release sheet was obtained.

Example 6
With respect to the acid-modified polyolefin resin aqueous dispersion E-1, an aqueous solution of an oxazoline compound (Epocross WS-500 manufactured by Nippon Shokubai Co., Ltd., solid content concentration 40% by mass) and polyvinyl alcohol (VC-10 manufactured by Nippon Vinegar Pover Co., Ltd.) 8 mass% aqueous solution with a polymerization degree of 1000 (hereinafter sometimes referred to as “PVA”) is 10 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin, and 100 parts by mass of the acid-modified polyolefin resin. On the other hand, the liquid substance added so that polyvinyl alcohol might be 50 mass parts was obtained. This liquid material is coated on the corona-treated surface of a biaxially stretched polyester film (Embret S-125, thickness 125 μm, manufactured by Unitika Co., Ltd.) as a base material using a Mayer bar, dried at 120 ° C. for 30 seconds, A release layer having a thickness of 0.3 μm was formed on the film. Then, the release sheet was obtained by performing aging at 50 degreeC for 2 days.

Example 7
Instead of the acid-modified polyolefin resin aqueous dispersion E-1 in Example 6, an acid-modified polyolefin resin aqueous dispersion E-2 was used. Otherwise by performing the same operations as in Example 6, a release sheet was obtained.

Example 8
Instead of the acid-modified polyolefin resin aqueous dispersion E-1 in Example 6, an acid-modified polyolefin resin aqueous dispersion E-3 was used. Otherwise by performing the same operations as in Example 6, a release sheet was obtained.

Example 9
Instead of the acid-modified polyolefin resin aqueous dispersion E-1 in Example 6, an acid-modified polyolefin resin aqueous dispersion E-4 was used. And oxazoline compound solid content was made into 5 mass parts with respect to 100 mass parts of acid-modified polyolefin resin. Otherwise by performing the same operations as in Example 6, a release sheet was obtained.

Example 10
In place of the acid-modified polyolefin resin aqueous dispersion E-4 in Example 9, an acid-modified polyolefin resin aqueous dispersion E-5 was used. Otherwise by performing the same operations as in Example 9, a release sheet was obtained.

Example 11
Compared with Example 6, it changed so that polyvinyl alcohol might be 1 mass part with respect to 100 mass parts of acid-modified polyolefin resin. Otherwise by performing the same operations as in Example 6, a release sheet was obtained.

Example 12
Compared with Example 6, it changed so that polyvinyl alcohol might be 100 mass parts with respect to 100 mass parts of acid-modified polyolefin resin. Otherwise by performing the same operations as in Example 6, a release sheet was obtained.

Example 13
Compared with Example 6, it changed so that polyvinyl alcohol might be 300 mass parts with respect to 100 mass parts of acid-modified polyolefin resin. Otherwise by performing the same operations as in Example 6, a release sheet was obtained.

Example 14
Compared with Example 6, it changed so that polyvinyl alcohol might be 500 mass parts with respect to 100 mass parts of acid-modified polyolefin resin. Otherwise by performing the same operations as in Example 6, a release sheet was obtained.

Example 15
Compared with Example 6, it changed so that polyvinyl alcohol might be 1000 mass parts with respect to 100 mass parts of acid-modified polyolefin resin. Otherwise by performing the same operations as in Example 6, a release sheet was obtained.

Example 16
Compared with Example 9, it changed so that polyvinyl alcohol might be 300 mass parts with respect to 100 mass parts of acid-modified polyolefin resin. Otherwise by performing the same operations as in Example 9, a release sheet was obtained.

Example 17
Compared with Example 9, it changed so that polyvinyl alcohol might be 1000 mass parts with respect to 100 mass parts of acid-modified polyolefin resin. Otherwise by performing the same operations as in Example 9, a release sheet was obtained.

Example 18
Compared with Example 6, it changed so that an oxazoline compound might be 50 mass parts with respect to 100 mass parts of acid-modified polyolefin resin. Otherwise by performing the same operations as in Example 6, a release sheet was obtained.

Example 19
Compared with Example 16, it changed so that an oxazoline compound might be 1 mass part with respect to 100 mass parts of acid-modified polyolefin resin. Otherwise by performing the same operations as in Example 16, a release sheet was obtained.

Example 20
Instead of the aqueous solution “WS-500” of the oxazoline compound in Example 6, an aqueous solution of a polycarbodiimide compound (“V-02” manufactured by Nisshinbo Co., Ltd., solid concentration 40 mass%, hereinafter sometimes referred to as “CI”) ) Was used. And it changed so that a polycarbodiimide compound might be 30 mass parts with respect to 100 mass parts of acid-modified polyolefin resin. Otherwise by performing the same operations as in Example 6, a release sheet was obtained.

Example 21
Instead of the aqueous solution “WS-500” of the oxazoline compound in Example 9, an aqueous solution CI of a polycarbodiimide compound was used. And it changed so that a polycarbodiimide compound might be 10 mass parts with respect to 100 mass parts of acid-modified polyolefin resin. Otherwise by performing the same operations as in Example 9, a release sheet was obtained.

Example 22
Instead of the biaxially stretched polyester film (Embret S-125, thickness 125 μm manufactured by Unitika) as the base material in Example 6, a biaxially stretched polyester kneaded mat film (PTH-50, thickness 50 μm manufactured by Unitika) was used. . Otherwise by performing the same operations as in Example 6, a release sheet was obtained.

Example 23
In place of the biaxially stretched polyester film (Embret S-125, thickness 125 μm, manufactured by Unitika Ltd.) as the base material in Example 16, a biaxially stretched polyester kneaded mat film (PTH-50, thickness 50 μm manufactured by Unitika Ltd.) was used. . Otherwise by performing the same operations as in Example 16, a release sheet was obtained.

Example 24
Instead of the biaxially stretched polyester film (Embret S-125, thickness 125 μm, manufactured by Unitika Ltd.) as a base material in Example 6, a polyester sand mat film (SM-125, thickness 125 μm manufactured by Unitika Ltd.) was used. Otherwise by performing the same operations as in Example 6, a release sheet was obtained.

Example 25
Instead of the biaxially stretched polyester film (Embret S-125, thickness 125 μm, manufactured by Unitika) as the base material in Example 9, a polyester sand mat film (SM-125, thickness 125 μm, manufactured by Unitika) was used. Otherwise by performing the same operations as in Example 9, a release sheet was obtained.

  The evaluation result about each release sheet of Examples 1-25 is shown in Tables 3-5.

Comparative Example 1
Without forming a release layer on a biaxially stretched polyester resin film (Embret S-125, thickness 125 μm, manufactured by Unitika Ltd.), the corona untreated surface of the film was evaluated.

Comparative Example 2
The corona-treated surface of a biaxially stretched polyester film (“Embret S-125” manufactured by Unitika) was coated with an acid-modified polyolefin resin aqueous dispersion E-1 so that the thickness was 5 μm. Furthermore, a stretched polypropylene film (# 20u-1 thickness 20 μm, manufactured by Tosero Co., Ltd.) is laminated thereon, and pressed with a heat press machine at 2 kg / cm ² and a temperature of 110 ° C. for 5 seconds to obtain a release sheet. It was. The acid-modified polyolefin resin aqueous dispersion E-1 was not used as a release layer, but as an adhesive for adhering polyester as a base material to an acid-modified polypropylene film as a release layer.

Comparative Example 3
Compared to Example 1, a silicone release agent (manufactured by Toshiba Silicone Co., Ltd., trade name “ TSM6341 ”, solid concentration: 40% by mass) was coated to a thickness of 0.3 μm to obtain a release sheet.

Comparative Example 4
Instead of the acid-modified polyolefin resin aqueous dispersion E-1 in Example 1, an acid-modified polyolefin resin aqueous dispersion E-6 was used. Otherwise, the same operation as in Example 1 was performed to obtain a release sheet.

Comparative Example 5
Instead of the acid-modified polyolefin resin aqueous dispersion E-1 in Example 6, an acid-modified polyolefin resin aqueous dispersion E-6 was used. Otherwise by performing the same operations as in Example 6, a release sheet was obtained.

Comparative Example 6
Compared with Example 1, the addition amount of the oxazoline compound was changed to 60 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin. Otherwise, the same operation as in Example 1 was performed to obtain a release sheet.

Comparative Example 7
A corona-treated surface of a biaxially stretched polyester film (trade name “Emblet S-125” manufactured by Unitika Ltd.) is coated with acid-modified polyolefin E-1 to a thickness of 0.3 μm, and a release sheet is formed. Obtained.

Comparative Example 8
In the acid-modified polyolefin resin aqueous dispersion E-1, an aqueous solution of polyvinyl alcohol (VC-10, degree of polymerization 1000, manufactured by Nippon Vinegar Poval Co., Ltd.) was added to 50 parts by mass of polyvinyl alcohol with respect to 100 parts by mass of the acid-modified polyolefin resin. Was added to obtain a liquid. This liquid material is coated on a corona-treated surface of a biaxially stretched polyester film (trade name “Emblet S-125”, manufactured by Unitika Ltd.) as a base material using a Mayer bar, and dried at 120 ° C. for 30 seconds. Then, a release layer having a thickness of 0.3 μm was formed on the film. Then, the release sheet was obtained by performing aging at 50 degreeC for 2 days.

  Table 6 shows the evaluation results for the release sheets of Comparative Examples 1 to 8.

  In Examples 1 to 25, a release layer containing an acid-modified polyolefin resin having an acid-modified component of 1 to 10% by mass, a crosslinking agent, and optionally included polyvinyl alcohol in a range specified in the present invention, It was the release sheet formed on the base material. For this reason, in the manufacturing process of the synthetic leather, no release or peeling occurred, and the release sheet could be easily peeled off. In addition, the releasability did not change greatly even after repeated use, and the reusability was excellent. Among these, those containing the three of acid-modified polyolefin resin having an acid-modified component of 1 to 10% by mass, a crosslinking agent, and polyvinyl alcohol have relatively low peel strength, and the peel strength changes after repeated use. And was excellent as a release sheet for the synthetic leather manufacturing process.

  On the other hand, since Comparative Example 1 was a polyester film not provided with a release layer, the release property from the synthetic leather was poor, and it was difficult to use it as a release sheet in the synthetic leather manufacturing process. .

  In Comparative Example 2, since a polypropylene resin that was not acid-modified was used as a release layer, although it was excellent in releasability and repeated use, floating / peeling occurred during the manufacturing process. Use as a release sheet in the manufacturing process has been difficult.

  Since Comparative Example 3 was a release sheet in which a silicone-type release agent was coated on a polyester film, it could not be said that the peel strength was too small to have an appropriate release property, and it floated during the manufacturing process. Peeling also occurred and it was difficult to use as a release sheet in the synthetic leather manufacturing process.

  Since Comparative Example 4 and Comparative Example 5 used an acid-modified polyolefin resin having a modified amount outside of the present invention, the releasability from the synthetic leather was poor, and the use as a release sheet in the synthetic leather production process was It was difficult.

In Comparative Example 6, since the addition amount of the crosslinking agent was outside the range of the present invention, the releasability from the synthetic leather was poor, and it was difficult to use as a release sheet in the synthetic leather manufacturing process. .
Since the comparative example 7 was a thing which does not add a crosslinking agent, the release property from synthetic leather was bad, and the use as a release sheet in a synthetic leather manufacturing process was difficult.

  Since Comparative Example 8 contained polyvinyl alcohol but did not contain a crosslinking agent, the releasability from synthetic leather was poor, and it was difficult to use as a release sheet in the synthetic leather manufacturing process.

Claims (7)

  A release sheet for a synthetic leather manufacturing process in which a release layer is laminated on at least one side of a base material, wherein the release layer is an acid-modified polyolefin resin having an acid-modified component of 1 to 10% by mass, and the acid-modified A release sheet for a synthetic leather manufacturing process, which is formed of a resin composition containing 1 to 50 parts by mass of a crosslinking agent with respect to 100 parts by mass of a polyolefin resin.   The release sheet for synthetic leather production process according to claim 1, wherein the resin composition forming the release layer contains 1-1000 parts by mass of polyvinyl alcohol with respect to 100 parts by mass of the acid-modified polyolefin resin. .   The release sheet for a synthetic leather manufacturing process according to claim 1 or 2, wherein the base material is a resin material.   The release sheet for synthetic leather production process according to claim 3, wherein the substrate is a polyester film.   The peel strength for the synthetic leather manufacturing process according to any one of claims 1 to 4, wherein the peel strength between the release layer and the synthetic leather resin layer is 0.1 to 3.0 N / cm. Mold sheet.   The release sheet for synthetic leather production process according to any one of claims 1 to 5, wherein the release sheet can be used when producing synthetic leather by a wet method.   A composition comprising: a liquid material containing 100 parts by mass of an acid-modified polyolefin resin having an acid-modified component of 1 to 10% by mass and 1 to 50 parts by mass of a crosslinking agent; A method for producing a release sheet for a leather production process.