WO2015064599A1

WO2015064599A1 - Mold release sheet

Info

Publication number: WO2015064599A1
Application number: PCT/JP2014/078683
Authority: WO
Inventors: 暢康奥村
Original assignee: ユニチカ株式会社
Priority date: 2013-10-29
Filing date: 2014-10-29
Publication date: 2015-05-07
Also published as: JPWO2015064599A1; JP6516681B2; TW201522042A; TWI630106B

Abstract

This mold release sheet, which results from providing a resin layer on a substrate, is characterized by the resin layer containing 0.1-50 parts by mass of a cross-linking agent for every 100 parts by mass of an acid-modified ethylene-α-olefin copolymer and the cross-linking agent comprising an oxazoline compound and/or a carbodiimide compound.

Description

Release sheet

The present invention relates to a release sheet.

Adhesive sheets are used in various applications including manufacturing processes of electronic parts such as semiconductor devices and precision equipment. In order to protect the surface of such an adhesive sheet, a release sheet is laminated and laminated until it is used.
A resin layer containing a release agent is provided on the surface of the base material constituting the release sheet so that the release sheet can be easily peeled off. Silicone release agents are most frequently used as release agents for release sheets. However, when a silicone release agent is used, the low molecular weight silicone compound contained in the silicone release agent may migrate to the adhesive surface of the adhesive sheet and remain. The silicone compound remaining on the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet not only causes a decrease in the pressure-sensitive adhesive force of the pressure-sensitive adhesive, but also gradually vaporizes, for example, by depositing on the surface of the electronic component in which the pressure-sensitive adhesive sheet is used, It was pointed out that it adversely affects its performance.

As a non-silicone release agent for a release sheet, Patent Documents 1 and 2 propose using an olefin elastomer, and Patent Documents 3 and 4 propose using an acid-modified polyolefin. . Patent Document 5 proposes using acid-modified polybutadiene or acid-modified polyisoprene.
The release sheets of Patent Documents 1 and 2 exhibit good release properties with respect to the pressure-sensitive adhesive sheet. However, since these release sheets have low heat resistance, when stored at a high temperature in a state of being bonded to the pressure-sensitive adhesive sheet, the release sheet strongly adheres to the pressure-sensitive adhesive sheet, and handling properties may be deteriorated. In particular, when heat is applied at the time of drying after application of the pressure-sensitive adhesive or at the time of transfer of the pressure-sensitive adhesive sheet, the release sheet tends to change its releasability, which is undesirable in handling.
On the other hand, in the release sheets of Patent Documents 3 and 4, an acid-modified ethylene polymer is used as a release agent, and exhibits good release properties for various adherends. . However, the adhesive sheet has a slightly high peel strength, so the handling properties when peeling the adhesive sheet may not be good, especially when releasing the release sheet from the adhesive sheet at high speed. In some cases, the smoothness and transparency of the pressure-sensitive adhesive sheet surface may be impaired.
Although the release sheet of Patent Document 5 has good release properties with respect to the pressure-sensitive adhesive, the release layer is soft, so that when the release sheet is rolled up, blocking of the sheet occurs, and the roll There is a problem in production that there is a risk that it may not be possible to unwind the sheet.

Japanese Patent No. 4907724 Japanese Patent No. 4367082 JP 2009-101680 A International Publication No. 2009/025063 JP 2012-152965 A

In view of these problems, the present invention aims to provide a release sheet that is excellent in releasability from an adhesive material, has good handling properties even at high-speed peeling, and is excellent in heat resistance and blocking resistance. To do.

As a result of diligent studies to solve the above problems, the present inventor used an acid-modified ethylene-α-olefin copolymer as a release agent, and formed a resin layer containing this and a specific crosslinking agent. It has been found that a release sheet provided on a substrate solves the above problems, and has reached the present invention.
That is, the gist of the present invention is as follows.

(1) A release sheet having a resin layer provided on a substrate, the resin layer comprising 100 parts by mass of an acid-modified ethylene-α-olefin copolymer and 0.1 to 50 parts by mass of a crosslinking agent. A release sheet comprising: a crosslinking agent comprising an oxazoline compound and / or a carbodiimide compound.
(2) The mass ratio (ethylene component / α-olefin component) of the ethylene component and α-olefin component constituting the acid-modified ethylene-α-olefin copolymer is 60/40 to 99/1 The release sheet according to (1).
(3) The release sheet according to (1) or (2), wherein the α-olefin component is propylene or 1-butene.
(4) The content of the acid-modified component constituting the acid-modified ethylene-α-olefin copolymer is less than 1% by mass with respect to the total of the ethylene component and the α-olefin component ( The release sheet according to any one of 1) to (3).
(5) The release sheet according to any one of (1) to (4), wherein the substrate is any one of a resin material, paper, synthetic paper, cloth, metal material, and glass material.
(6) The release sheet according to (5), wherein the resin material is a polyester resin film.
(7) The release sheet according to any one of (1) to (6), wherein the peel strength between the resin layer and the acrylic adhesive material is 0.5 N / cm or less.

By using the release sheet of the present invention, the pressure-sensitive adhesive surface of the pressure-sensitive adhesive material can be protected, and even when the release sheet is peeled off at high speed during use of the pressure-sensitive adhesive material, the quality of the pressure-sensitive adhesive material is not impaired. Can be peeled off. Moreover, since the release sheet of this invention is excellent in heat resistance, it is excellent in the mold release property after heat processing, after bonding with an adhesive material etc. Furthermore, the release sheet of the present invention is excellent in blocking resistance even when rolled up in a roll.

Hereinafter, the present invention will be described in detail.
The release sheet of this invention is comprised from a base material and the resin layer provided on it. The resin layer contains an acid-modified ethylene-α-olefin copolymer and a crosslinking agent.

The acid-modified ethylene-α-olefin copolymer is obtained by acid-modifying an ethylene-α-olefin copolymer. The ethylene-α-olefin copolymer comprises an ethylene component and one or more α-olefin components. Containing.
Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene and the like can be mentioned. Among these, propylene and 1-butene are preferable from the viewpoints of economy and availability.

In the ethylene-α-olefin copolymer, the mass ratio of the ethylene component to the α-olefin component (ethylene component / α-olefin component) is preferably 60/40 to 99/1, and preferably 70/30 to 97. / 3 is more preferable, and 80/20 to 95/5 is still more preferable. If the mass ratio of the ethylene component to the α-olefin component is outside this range, the resulting release sheet may have poor release properties and may have high speed peelability.

The ethylene-α-olefin copolymer is preferably produced using a metallocene catalyst. The ethylene-α-olefin copolymer produced by this method has a narrow molecular weight distribution, a small amount of low molecular weight components, and uniform copolymerization.

In the present invention, the ethylene-α-olefin copolymer is acid-modified from the viewpoint of improving the adhesion between the resulting resin layer and the substrate and improving the heat resistance by reacting with a crosslinking agent. is required. The acid modification of the ethylene-α-olefin copolymer can be performed, for example, by introducing an unsaturated carboxylic acid component into the ethylene-α-olefin copolymer.
In the present invention, the content of the acid-modified component constituting the acid-modified ethylene-α-olefin copolymer is less than 1% by mass with respect to the total amount of the olefin component, that is, the total amount of the ethylene component and the α-olefin component. Is preferably 0.01% by mass or more and less than 1% by mass, more preferably 0.05% by mass or more and less than 1% by mass, and further preferably 0.1% by mass or more and 1% by mass. Is particularly preferably 0.2% by mass or more and less than 1% by mass. When the content of the acid-modified component is less than 0.01% by mass, the adhesion to the substrate may be insufficient, or the reaction with the crosslinking agent may be insufficient, resulting in poor heat resistance. On the other hand, when the content of the acid-modified component is 1% by mass or more, the releasability tends to decrease. In addition, when a polyolefin resin containing an ethylene component is usually acid-modified, a cross-linking reaction also proceeds in concert. Therefore, it is substantially difficult to produce a product having a high acid-modified amount from the viewpoint of operability. May be.

Specific examples of the unsaturated carboxylic acid component to be introduced into the ethylene-α-olefin copolymer include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, aconitic acid, aconitic anhydride, In addition to fumaric acid, crotonic acid, citraconic acid, mesaconic acid, allyl succinic acid, etc., at least one carboxyl group or acid anhydride in the molecule (in the monomer unit) such as half ester or half amide of unsaturated dicarboxylic acid The compound which has a physical group is mentioned. Of these, maleic anhydride, acrylic acid and methacrylic acid are preferred, and maleic anhydride is more preferred from the viewpoint of ease of introduction into the ethylene-α-olefin copolymer.
The unsaturated carboxylic acid component only needs to be copolymerized in the ethylene-α-olefin copolymer, and the form thereof is not limited, and examples thereof include random copolymerization, block copolymerization, and graft copolymerization. It is done.

The method for introducing the unsaturated carboxylic acid unit into the ethylene-α-olefin copolymer is not particularly limited. For example, a method in which an ethylene-α-olefin copolymer and an unsaturated carboxylic acid are heated and melted to a temperature higher than the melting point of the ethylene-α-olefin copolymer in the presence of a radical generator, or an ethylene-α-olefin is reacted. After dissolving the copolymer and unsaturated carboxylic acid in an organic solvent, the unsaturated carboxylic acid is added to the ethylene-α-olefin copolymer by a method of reacting by heating and stirring in the presence of a radical generator. A method of graft copolymerization may be mentioned. The former method is preferable because the operation is simple.
Examples of the radical generator used for graft copolymerization include di-tert-butyl peroxide, dicumyl peroxide, tert-butyl hydroperoxide, tert-butyl cumyl peroxide, benzoyl peroxide, dilauryl peroxide, Examples thereof include organic peroxides such as cumene hydroperoxide, tert-butyl peroxybenzoate, ethyl ethyl ketone peroxide, and di-tert-butyl diperphthalate, and azonitriles such as azobisisobutyronitrile. These may be appropriately selected and used depending on the reaction temperature.

In the present invention, the melt flow rate of the acid-modified ethylene-α-olefin copolymer as a raw material for producing the resin layer is not particularly limited, but is preferably 0.01 to 500 g / 10 min at 230 ° C. and 2160 g load. 0.1 to 100 g / 10 min is more preferable, and 0.3 to 10 g / 10 min is still more preferable. An acid-modified ethylene-α-olefin copolymer having a melt flow rate of less than 0.01 g / 10 minutes is difficult to dissolve in a solvent, while the melt flow rate of the acid-modified ethylene-α-olefin copolymer is difficult. Is 500 g / 10 min or more, the resulting resin layer may have poor adhesion to the substrate, and migration of low molecular weight components tends to occur on the adherend such as an adhesive.

A commercially available ethylene-α-olefin copolymer can be used as the ethylene-α-olefin copolymer for acid modification. Examples of commercially available ethylene-α-olefin copolymers include the Esprene series manufactured by Sumitomo Chemical Co., Ltd. and the Tuffmer series manufactured by Mitsui Chemicals. An acid-modified ethylene-α-olefin copolymer can be obtained by performing acid modification using the commercially available ethylene-α-olefin copolymer by the method described above.
A commercially available acid-modified ethylene-α-olefin copolymer may be used. Examples of commercially available acid-modified ethylene-α-olefin copolymers include Tuffmer series MP-0620, MH-7020, and MA-8510 manufactured by Mitsui Chemicals.

The resin layer of the release sheet of the present invention contains a crosslinking agent. As the crosslinking agent, a compound having in its molecule a plurality of functional groups that react with the acid-modified ethylene-α-olefin copolymer is used, and at least one crosslinking selected from oxazoline compounds and carbodiimide compounds from the viewpoint of reactivity. It is necessary to be an agent. When a crosslinking agent other than an oxazoline compound or a carbodiimide compound is used as the crosslinking agent, the crosslinking reaction becomes insufficient, so that the resulting resin layer tends to have a reduced heat resistance and a reduced release property after heat treatment.

The oxazoline compound is not particularly limited as long as it has two or more 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) And compounds having an oxazoline group such as bis (2-oxazolinylcyclohexane) sulfide and polymers containing an oxazoline group. These 1 type (s) or 2 or more types can be used. Among these, an oxazoline group-containing polymer is preferable because of ease of handling.
The oxazoline group-containing polymer can be 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.
Commercially available products of the oxazoline group-containing polymer include EPOCROSS series manufactured by Nippon Shokubai Co., Ltd. Specifically, water-soluble type “WS-500”, “WS-700”, solid type “RPS-1005” Or the like.

The carbodiimide compound is not particularly limited as long as it has at least two or more 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 1 type (s) or 2 or more types can be used. Among these, polycarbodiimide is preferable from the viewpoint of ease of handling.
The method for producing polycarbodiimide is not particularly limited. Polycarbodiimide can be produced, for example, by a condensation reaction involving decarbonization of an isocyanate compound. The isocyanate compound is not limited, and any of aliphatic isocyanate, alicyclic isocyanate, and aromatic isocyanate may be used. The isocyanate compound may be copolymerized with a polyfunctional liquid rubber or polyalkylene diol as necessary.
Examples of commercially available products of polycarbodiimide include the Carbodilite series manufactured by Nisshinbo Co., Ltd. Specifically, water-soluble types “SV-02”, “V-02”, “V-02-L2”, “ V-04 ”, organic solution type“ V-01 ”,“ V-03 ”,“ V-07 ”,“ V-09 ”, solventless type“ V-05 ”, and the like.

The content of the crosslinking agent comprising the oxazoline compound and / or carbodiimide compound must be 0.1 to 50 parts by mass with respect to 100 parts by mass of the acid-modified ethylene-α-olefin copolymer. The amount is preferably 30 parts by mass, and more preferably 2 to 20 parts by mass. When the content of the crosslinking agent is less than 0.1 parts by mass, the effect of addition is poor, the releasability may deteriorate over time, or sufficient heat resistance may not be obtained, and the content exceeds 50 parts by mass. In some cases, the releasability may be reduced. In addition, a several kind of crosslinking agent can also be used simultaneously, and when it is used simultaneously, the total amount of a crosslinking agent should just satisfy | fill the range of content of said crosslinking agent.

The resin layer constituting the release sheet of the present invention contains an acid-modified ethylene-α-olefin copolymer and a cross-linking agent as described above. If necessary, a leveling agent and an antifoaming agent are used. Further, it may contain various agents such as anti-waxing agents, antistatic agents, pigment dispersants, ultraviolet absorbers, and pigments or dyes such as titanium oxide, zinc white and carbon black. In addition, organic or inorganic compounds other than those described above can be added to the liquid material and contained in the resin layer as long as the stability of the liquid material for forming the resin layer described later is not impaired.

In the release sheet of the present invention, the thickness of the resin layer is preferably 0.01 to 5.0 μm, more preferably 0.03 to 3.0 μm, and 0.05 to 1.0 μm. Is more preferable. If the thickness of the resin layer is less than 0.01 μm, sufficient releasability may not be obtained. On the other hand, if the thickness exceeds 5.0 μm, the cost increases, which is not preferable.

In the present invention, the method for providing the resin layer on the substrate is not particularly limited. For example, a method of preparing a liquid material containing an acid-modified ethylene-α-olefin copolymer, a cross-linking agent, and a medium, applying the liquid material on a substrate, and drying the medium can be achieved by the thickness of the resin layer. It is preferable in that it can be easily made uniform and mass production is possible. Alternatively, a resin layer may be formed by melt-extruding a mixture of an acid-modified ethylene-α-olefin copolymer and a crosslinking agent onto a substrate. Moreover, you may obtain a release sheet by coextruding the resin material which comprises a base material, and resin layer forming material.

An organic solvent capable of dissolving or dispersing the acid-modified ethylene-α-olefin and the crosslinking agent as a medium for producing the liquid containing the acid-modified ethylene-α-olefin copolymer and the crosslinking agent, Those that can be removed by drying in the course of film formation can be used. From the viewpoint of efficient removal from the coating film, the boiling point of the organic solvent is preferably 150 ° C. or lower. An organic solvent having a boiling point of more than 150 ° C. tends to be difficult to scatter from the coating film by drying, and in particular, the adhesion property and content resistance of the coating film may decrease.
Examples of the organic solvent include acetone, methyl ethyl ketone, diethyl ketone (3-pentanone), methyl propyl ketone (2-pentanone), isobutyl ketone, methyl isobutyl ketone (4-methyl-2-pentanone), 2-hexanone, 5- Ketones such as methyl-2-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, cyclopentanone, cyclohexanone; aromatic hydrocarbons such as toluene, xylene, benzene, Solvesso 100, Solvesso 150; Aliphatic hydrocarbons such as butane, pentane, hexane, cyclohexane, heptane, octane, nonane; methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, chlorobenzene, o -Dichlorobenzene, m-dic Halogenated compounds such as benzene and p-dichlorobenzene; methyl acetate, ethyl acetate, acetic acid-n-propyl, isopropyl acetate, acetic acid-n-butyl, acetic acid isobutyl, acetic acid-sec-butyl, acetic acid-tert-butyl, acetic acid- Esters such as 3-methoxybutyl, methyl propionate, ethyl propionate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, isophorone; methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, cyclohexanol, ethyl Alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether; ethers such as tetrahydrofuran and 1,4-dioxane; dimethylformamide, dimethylacetamide, diacetone alcohol, acetonitrile, In addition, ammonia, diethylamine, triethylamine, diethanolamine, triethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, N-diethanolamine, 3-methoxypropylamine, 3-diethylaminopropylamine, dimethylamino Organic amine compounds such as propylamine; and the like.
Among them, from the viewpoint of obtaining a stable liquid material and facilitating coating, aromatic hydrocarbons such as toluene, xylene, benzene, Solvesso 100, Solvesso 150, butane, pentane, hexane, cyclohexane, heptane, octane, nonane Aliphatic hydrocarbons such as toluene are preferred, and toluene is particularly preferred from the viewpoint of solubility.

In addition, two or more of the above organic solvents may be used in combination from the viewpoints of improving the stability of the liquid material, improving the solubility, applying to the substrate, and improving the coating appearance. When two or more types of organic solvents are used, it is preferable to use a combination of aromatic hydrocarbons and alcohols and / or ketones. When two or more organic solvents are used, the aromatic hydrocarbons are preferably toluene, xylene, etc. The alcohols are preferably methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, etc. As the class, acetone, methyl ethyl ketone, isobutyl ketone, methyl isobutyl ketone and the like are preferable.
By using these solvents in combination, the leveling property is improved, the interference fringes of the coating film are eliminated, and a release sheet excellent in coating appearance can be obtained. When a release sheet having interference fringes is used, the interference fringes may be transferred to the surface of an adhesive or the like, and may not be used for optical materials.
The mixing ratio in the case of mixing two or more organic solvents is not particularly limited, but the mass ratio of (aromatic hydrocarbon solvent) / (alcohol) to the aromatic hydrocarbon solvent and alcohols and / or ketones. And / or ketones)) is preferably 99/1 to 50/50, more preferably 97/3 to 70/30, and still more preferably 95/5 to 80/20.

In the method of forming a resin layer by applying 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, dipping A uniform resin layer is obtained by uniformly applying a liquid material to the surface of the substrate by coating, brushing, etc., setting it at around room temperature as necessary, and then subjecting it to drying treatment or heat treatment for drying. Can be formed in close contact with the substrate.

After the resin layer is formed on the substrate, an aging treatment may be performed in an environment controlled at a constant temperature in order to promote the reaction between the acid-modified ethylene-α-olefin copolymer and the crosslinking agent. . The aging temperature is preferably relatively low from the viewpoint of reducing damage to the substrate, but it is preferable to treat at a high temperature from the viewpoint of allowing the reaction to proceed sufficiently and rapidly. The aging treatment is preferably performed at 20 to 100 ° C, more preferably at 30 to 70 ° C, and further preferably at 40 to 60 ° C.

As a method for producing a liquid material containing an acid-modified ethylene-α-olefin copolymer, a crosslinking agent, and a medium, an acid-modified ethylene-α-olefin copolymer, a crosslinking agent, The method of dissolving is mentioned.
Further, as a method for producing a liquid material, a method in which an acid-modified ethylene-α-olefin copolymer is made into an aqueous dispersion and a crosslinking agent is mixed can be mentioned. The method for dispersing the acid-modified ethylene-α-olefin copolymer in an aqueous medium and obtaining the aqueous dispersion is not particularly limited. For example, the acid-modified ethylene-α-olefin copolymer, an organic solvent, Examples thereof include a method of preparing an aqueous dispersion by introducing a raw material such as water and stirring while maintaining the temperature in the tank at about 40 to 150 ° C. For example, a method described in International Publication No. 02/055598 pamphlet can be mentioned, and a good aqueous dispersion can be obtained by neutralizing an acid-modified ethylene-α-olefin copolymer with a basic compound in an aqueous medium. Is obtained.

The solid content in the liquid material can be appropriately selected depending on the formation conditions, thickness, performance, and the like of the resin layer, and is not particularly limited. In order to form a layer, 1 to 60% by mass is preferable, and 2 to 20% by mass is more preferable.

Examples of the base material constituting the release sheet include those formed of resin material, paper, synthetic paper, cloth, metal material, glass material, and the like. The thickness of the substrate is not particularly limited, but it may usually be 1 to 1000 μm, preferably 1 to 500 μm, more preferably 10 to 200 μm, and particularly preferably 25 to 100 μm.

Examples of resin materials that can be used for the substrate include polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polylactic acid (PLA) as thermoplastic resins; polyolefin resins such as polypropylene; polystyrene resins; Polyamide resin such as nylon 6, poly-m-xylylene adipamide (MXD6 nylon); polycarbonate resin; polyacrylonitrile resin; polyimide resin; multilayer of these resins (for example, nylon 6 / MXD6 nylon / nylon 6) And nylon 6 / ethylene-vinyl alcohol copolymer / nylon 6) and mixtures.
The resin material may be stretched. Among them, the base material is preferably a polyester resin film excellent in mechanical properties and thermal properties, and is preferably a polyethylene terephthalate film from the viewpoint of being inexpensive and easily available.

When a liquid material is applied to a thermoplastic resin film, it may be dried and heat-treated after being applied to a biaxially stretched film, or it may be liquid on an unstretched film before or after completion of uniaxial stretching. The product may be applied and dried and heated to stretch, or heated and stretched simultaneously with drying to complete the orientation. The method of applying the liquid to the latter unstretched film or the film after uniaxial stretching, followed by drying and stretching orientation allows the resin layer to be laminated simultaneously with the formation of the thermoplastic resin film. To preferred.

The thermoplastic resin film may contain a known additive or stabilizer, such as an antistatic agent, a plasticizer, a lubricant, or an antioxidant. The thermoplastic resin film may be vapor-deposited with silica, alumina, or the like, and may be laminated with other layers such as a barrier layer, an easy adhesion layer, an antistatic layer, and an ultraviolet absorption layer. In order to improve the adhesion when laminating with other materials, the surface of the thermoplastic resin film may be subjected to corona treatment, plasma treatment, ozone treatment, chemical treatment, solvent treatment, etc. as pretreatment.

Examples of paper that can be used as the substrate include Japanese paper, kraft paper, liner paper, art paper, coated paper, carton paper, glassine paper, semi-glassine paper, and the like. The paper may be provided with a sealing layer or the like.
The structure of the synthetic paper that can be used as the substrate is not particularly limited, and may be 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 cloth that can be used as the substrate include fibers made of the above-described synthetic resin, nonwoven fabrics made of natural fibers such as cotton, silk, and linen, woven cloth, and knitted cloth.
Examples of the metal material that can be used as 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 that can be used as the substrate include a glass plate and a cloth made of glass fiber.

Since the release sheet of the present invention has a good releasability for various materials, it can be used for various materials, and the release sheet of the present invention can be used via a resin layer. By stacking on the adherend, a stacked body can be obtained.
Specifically, the release sheet of the present invention is a sheet as a protective material for adhesive materials and liquid crystal display parts, as a process material for prepregs used in press process materials for printed wiring boards, structural materials for aircraft, etc. As a base substrate at the time of production of the shaped structure, it can be suitably used as a release sheet for transfer printing. In particular, it can be suitably used for an adhesive material.

Examples of the adhesive material include an adhesive sheet, an adhesive sheet, an adhesive tape, and an adhesive tape. More specifically, an adhesive is laminated on a base material. The component and base material of the pressure-sensitive adhesive are not particularly limited, but examples of the pressure-sensitive adhesive include acrylic pressure-sensitive adhesives, natural rubber-based pressure-sensitive adhesives, synthetic rubber-based pressure-sensitive adhesives, and silicone-based pressure-sensitive adhesives. Coumarone-indene-based, terpene-based, petroleum-based, styrene-based, phenol-based, and xylene-based tackifiers may be included. Examples of the substrate include the above-described paper, cloth, and resin material.
The release sheet used for the pressure-sensitive adhesive material is required to have excellent releasability in handling, for example, a sheet having a peel strength of 0.5 N / cm or less from the acrylic pressure-sensitive adhesive material. It has been demanded. When the release sheet of the present invention is used for an acrylic pressure-sensitive adhesive material, the peel strength between the resin layer and the acrylic pressure-sensitive adhesive material after the acrylic pressure-sensitive adhesive material is pasted and allowed to stand is 0.5 N / cm or less, more preferably 0.4 N / cm or less, still more preferably 0.3 N / cm or less, and most preferably 0.2 N / cm or less. When the peel strength with an acrylic adhesive material exceeds 0.5 N / cm, when the release sheet is peeled from the adhesive material, resistance is felt or the adhesive surface is roughened, resulting in a decrease in adhesiveness Therefore, it may be difficult to use as a release sheet for acrylic adhesive materials.
Moreover, it is possible to use the release sheet of this invention also with respect to the silicone type adhesive material which is a representative of the adhesive material with strong adhesive force. When a conventional silicone release sheet is used for the silicone-based adhesive material, the adhesiveness between the adhesive layer and the release layer is high, so that the adhesion is increased and it is difficult to peel off. On the other hand, the release sheet of the present invention can maintain good peelability even with respect to the silicone-based adhesive material. When used for a silicone-based adhesive material, it is preferable that the peel strength between the resin layer and the silicone-based adhesive material after the silicone-based adhesive material is pasted and left to be 1.0 N / cm or less, more preferably Is 0.8 N / cm or less, more preferably 0.7 N / cm or less.
Since the release sheet of the present invention is excellent in heat resistance, even if the adhesive material to which the release sheet is attached is exposed to a high temperature for a long time in the process of storage and distribution, the peel strength changes over time. No change in the peel strength between the resin layer and the adhesive material can be kept small even after a long time has elapsed after pasting.
Also, in the process of peeling the release sheet industrially, the release sheet is peeled at a speed generally exceeding 10 m / min as the work line speeds up, so that high-speed peeling from the adhesive material is possible. There is a need for a release sheet. Since the release sheet of the present invention has sufficient releasability, even if it is peeled from the adhesive material at a high speed, it can be peeled without sound and without feeling of resistance. That is, the release sheet of the present invention can suppress a decrease in transparency and adhesiveness due to a rough surface condition of the adhesive material due to a phenomenon called “zipping or stick-slip” during high-speed peeling. .

Examples of liquid crystal display components that can use the release sheet of the present invention as a protective material include polarizing plates, retardation plates, and retardation plates.

The release sheet of the present invention is also used as a prepreg process material. For example, a solution containing a resin such as an epoxy resin or a phenol resin and a curing agent is applied and dried to form a sheet. It can be suitably used as a carrier sheet.
Since the release sheet of the present invention also has heat resistance, the release property can be maintained even after high temperature treatment in the curing step. The prepreg may use a reinforcing material such as a woven fabric such as carbon fiber or glass fiber in order to enhance the reinforcing effect. Examples of the process in which the prepreg is used include a process for pressing a printed wiring board, a process for forming a structural member such as an aircraft, a bicycle, and a windmill, and a process for forming a sport / leisure product such as a golf shaft and a tennis racket. Examples of the printed wiring board include a single-sided printed wiring board, a double-sided printed wiring board, a flexible printed wiring board, and a multilayer printed wiring board.

Examples of sheet-like structures that can be produced using the release sheet of the present invention as a base substrate include rubber sheets such as silicone rubber, fluorine rubber, and urethane rubber, synthetic leather made of vinyl chloride and urethane, par Examples thereof include an ion exchange membrane made of a polymer electrolyte such as fluorosulfonic acid resin, a ceramic green sheet made of dielectric ceramics or glass, a heat radiating sheet containing a heat radiating material, and the like.
In these production steps, a sheet-like structure can be formed by applying and drying a raw material in a paste or slurry form with a solvent on the release sheet of the present invention as a base substrate. Alternatively, a sheet-like structure can be formed by extruding a molten resin on a release sheet.

When the release sheet of the present invention is used for transfer printing, various functional layers such as a printing layer, an electrode, and a protective layer are formed by coating on the release sheet of the present invention. The functional layer is heated and pressure-bonded to the transfer object to transfer the functional layer to the transfer object, and then the release sheet is peeled from the functional layer. Thus, the release sheet of this invention can be used for what is also called a stamping foil. Examples of the functional layer include metallic foil, pigment foil, multicolor printing foil, hologram foil, electrostatic breakdown foil, and half mirror metallic foil.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

(1) Unsaturated carboxylic acid component content of acid-modified ethylene-α-olefin copolymer The content of unsaturated carboxylic acid component relative to the total amount of olefin component is determined using the method (A) or (B) shown below. It was.
(A): The acid value of the acid-modified ethylene-α-olefin copolymer was measured in accordance with JIS K5407, and the content (graft ratio) of the unsaturated carboxylic acid was determined from the value from the following formula.
Content (mass%) = (mass of grafted unsaturated carboxylic acid) / (mass of raw material polyolefin resin) × 100
(B): Infrared absorption spectrum analysis (Perkin Elmer Fourier transform infrared spectrophotometer System-2000, resolution 4 cm ⁻¹ ) was performed to determine the content of the unsaturated carboxylic acid component.

(2) Configuration of acid-modified ethylene-α-olefin copolymer other than unsaturated carboxylic acid component ¹ H-NMR, ¹³ C-NMR analysis (manufactured by Varian, Inc.) in orthodichlorobenzene (d ₄ ) at 120 ° C. , 300 MHz). ^{In the 13} C-NMR analysis, measurement was performed using a gated decoupling method in consideration of quantitativeness.

(3) Melt flow rate of acid-modified ethylene-α-olefin copolymer Measured by a method according to JIS K7210 (230 ° C., 2160 g load).

(4) Peel strength for acrylic adhesive (at room temperature)
An acrylic pressure-sensitive adhesive tape (Nitto Denko Corporation, No. 31B / acrylic pressure-sensitive adhesive) having a width of 50 mm and a length of 150 mm was pressure-bonded to the resin layer side of the obtained release sheet with a rubber roll to prepare a sample. The sample was sandwiched in the form of a metal plate / rubber plate / sample / rubber plate / metal plate and allowed to stand in an atmosphere of 2 kPa load and 25 ° C. for 24 hours to obtain a sample for peel strength measurement. The peel strength between the adhesive tape and the release sheet of this peel strength measurement sample was measured with a tensile tester (manufactured by Intesco, precision universal material tester, type 2020) in a thermostatic chamber at 25 ° C. The peeling angle was 180 ° C. and the peeling speed was 300 mm / min.

(5) Peel strength for acrylic adhesive (70 ° C)
A sample for measuring peel strength was obtained by the method described in (4) above, except that the condition for leaving the sample was changed from an atmosphere of 25 ° C. to an atmosphere of 70 ° C. The peel strength between the adhesive tape and the release sheet of the peel strength measurement sample was measured by the method described in (4) above.

(6) High-speed peelability Using the sample for measuring peel strength obtained by the method described in (4) above, the release sheet portion is fixed to a stainless steel plate with a double-sided tape, and the end of the adhesive tape is attached The evaluation was performed using the following indices with the hand feeling and the sound generated at the time of peeling when held by hand and peeled at once (peeling speed of about 30 m / min).
○: No sound, no resistance, and peeling
Δ: A noise due to zipping occurs, and resistance is felt during peeling.
X: A loud sound is generated by zipping, and the resistance at the time of peeling is large, so that peeling at a peeling speed of about 30 m / min cannot be performed.

(7) Residual adhesion rate 50 mm width and length peeled from the release sheet surface by the peel strength test (normal temperature) of (4), the peel strength test (70 ° C.) of (5) and the high speed peel test of (6) A 150 mm polyester pressure-sensitive adhesive tape (Nitto Denko No. 31B / acrylic pressure-sensitive adhesive) was applied to a stainless steel plate (SUS304 thickness 1 mm), and left at room temperature for 20 hours at a load of 2 kPa. Thereafter, the peel strength between the polyester adhesive tape and the stainless steel plate was measured with a tensile tester (manufactured by Intesco, precision universal material tester, type 2020) in a thermostatic chamber at 25 ° C. The peeling angle was 180 degrees and the peeling speed was 300 mm / min. The peel strengths obtained by this measurement were F1 ₍₄₎ , F1 ₍₅₎ , and F1 ₍₆₎ , respectively.
A polyester adhesive tape (Nitto Denko No. 31B / acrylic adhesive) having a width of 50 mm and a length of 150 mm was attached to a stainless steel plate (SUS304 thickness 1 mm) and left at room temperature for 20 hours at a load of 2 kPa. Thereafter, the peel strength of the polyester adhesive tape and the film was measured with a tensile tester (manufactured by Intesco, precision universal material tester, type 2020) in a thermostatic chamber at 25 ° C. (peeling angle was 180 degrees, peeling rate was 300 mm / And the obtained peel strength was defined as F2.
The residual adhesion rate of each pressure-sensitive adhesive tape was obtained using the following formula.
Residual adhesion rate after standing at room temperature (%) = (F1 ₍₄₎ / F2) × 100
Residual adhesion rate after standing at 70 ° C. (%) = (F1 ₍₅₎ / F2) × 100
Residual adhesion rate after high speed peeling (%) = (F1 ₍₆₎ / F2) × 100
When the surface of the pressure-sensitive adhesive of the pressure-sensitive adhesive tape is contaminated by the release sheet or the surface of the pressure-sensitive adhesive tape becomes extremely rough during peeling, the re-tackiness of the pressure-sensitive adhesive tape is lowered, and the performance as the pressure-sensitive adhesive tape is impaired. Therefore, it is preferable that the residual adhesion rate is high.

(8) Peel strength (normal temperature, 70 ° C.), high-speed peelability, residual adhesion rate for silicone-based pressure-sensitive adhesive In the above (4) to (7), instead of an acrylic pressure-sensitive adhesive tape having a width of 50 mm and a length of 150 mm, a width The same procedure as (4) to (7) above was applied to the silicone adhesive except that a 25 mm and 150 mm long silicone adhesive tape (Nitto Denko Corporation, No. 336 / silicone adhesive) was used. Measurement of peel strength (normal temperature, 70 ° C.), evaluation of high-speed peelability, and measurement of residual adhesion rate were performed.

(9) Evaluation of coating appearance (interference fringes) Black glossy tape (Yamato vinyl tape 200-50-21) was pasted on the biaxially stretched polyester resin film surface of the obtained release sheet in a dark room. The coating fringe was evaluated by observing the degree of interference fringes visually while changing the angle 30 cm directly under a three-wavelength fluorescent lamp (FPL27EX-N, manufactured by Panasonic Corporation).
A: Interference fringes are hardly visible.
○: Interference fringes are slightly visible.
Δ: Weak interference fringes are visible.
X: Interference fringes are clearly visible.

(10) Blocking resistance Two pieces of the obtained release sheet having a size of 50 mm × 50 mm were cut out and overlapped so that the resin layer and the opposite surface of the resin layer were in contact with each other, and a load of 10 kPa was applied at 60 ° C. Then, after leaving for 24 hours, the load was removed and the mixture was cooled to room temperature, and then the blocking resistance was evaluated by examining the adhesion between the resin layer and the opposite surface of the resin layer.
○: Adhesion is not observed between the two sheets, or the two sheets are easily peeled off, and no change such as whitening is observed in the resin layer.
X: The resin layer causes cohesive failure, or the resin layer after the two sheets are peeled off is entirely white.

The following were used as the resin constituting the resin layer.
P-1:
100 g of an ethylene-propylene copolymer (ethylene / propylene = 75/25% by mass) was dissolved in 400 g of xylene heated to 130 ° C. in a four-necked flask under a nitrogen atmosphere. Next, 10 g of a toluene solution of maleic anhydride (5% by mass) and 5 g of a toluene solution of dicumyl peroxide (10% by mass) were respectively added to this solution over 30 minutes, and then the system was kept at 130 ° C. The reaction was performed for 4 hours. 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, and acid-modified ethylene-α-olefin copolymer P-1 obtained by drying under reduced pressure was used.

P-2:
Except for changing the ethylene-propylene copolymer (ethylene / propylene = 75/25 mass%) to the ethylene-propylene copolymer (ethylene / propylene = 55/45 mass%) in the production of P-1, the same The acid-modified ethylene-α-olefin copolymer P-2 obtained by the operation was used.

P-3:
In the production of P-1, except that ethylene-propylene copolymer (ethylene / propylene = 75/25% by mass) was changed to ethylene-butene copolymer (ethylene / 1-butene = 70/30% by mass), An acid-modified ethylene-α-olefin copolymer P-3 obtained by the same operation was used.

P-4:
In the production of P-1, the same thing except that the ethylene-propylene copolymer (ethylene / propylene = 75/25 mass%) was changed to the ethylene-propylene copolymer (ethylene / propylene = 90/10 mass%). The acid-modified ethylene-α-olefin copolymer P-4 obtained by the operation was used.

P-5:
In the production of P-1, acid-modified ethylene-α-olefin resin P-5 obtained by performing the same operation except that the amount of the maleic anhydride toluene solution (5% by mass) was changed to 3 g was used. did.

P-6:
In the production of P-1, an acid-modified ethylene-α-olefin copolymer P-6 obtained by performing the same operation except that the amount of a maleic anhydride toluene solution (5% by mass) was changed to 20 g. It was used.

P-7:
In the production of P-1, the same operation was carried out except that the amount of the maleic anhydride toluene solution (5% by mass) was changed to 40 g and the amount of the dicumyl peroxide toluene solution (10% by mass) was changed to 7 g. The acid-modified ethylene-α-olefin copolymer P-7 obtained above was used.

P-8:
In the production of P-1, except that ethylene-propylene copolymer (ethylene / propylene = 75/25% by mass) was changed to propylene-1-butene copolymer (propylene / butene = 70/30% by mass), An acid-modified propylene-α-olefin copolymer P-8 obtained by the same operation was used.

P-9:
Bondine “LX-4110” (maleic anhydride-modified polyethylene resin) manufactured by Arkema was used.

P-10
Claprene “LIR-403” (acid-modified polyisoprene, number average molecular weight 34,000, acid value 9 to 11 mgKOH / g) manufactured by Kuraray Co., Ltd. was used.

P-11:
An acid-modified ethylene-propylene copolymer (ethylene / propylene = 70/30% by mass) was used.

Table 1 shows the composition and characteristics of the resins P-1 to P-11 constituting the resin layer.

Example 1
The acid-modified ethylene-α-olefin copolymer P-1 was dissolved in toluene to prepare a 2% by mass solution. An acid-modified ethylene-α-olefin copolymer and a solution of an oxazoline compound (manufactured by Nippon Shokubai Co., Ltd., Epocross “WS-500”, solid concentration: 39% by mass, diluted with isopropanol) A liquid obtained by mixing 2 parts by mass with respect to 100 parts by mass of the acid-modified ethylene-α-olefin copolymer was prepared as a biaxially stretched polyester resin film (“Embret PET-38” manufactured by Unitika). After coating with a Meyer bar on a corona-treated surface having a thickness of 38 μm), it was dried at 140 ° C. for 15 seconds to form a 0.2 μm-thick resin layer on the film, and then at 50 ° C. for 2 days. A release sheet was obtained by aging.

Examples 2 to 10, Comparative Examples 1, 4 to 6
A release sheet was obtained in the same manner as in Example 1, except that the type of acid-modified ethylene-α-olefin copolymer and the type and content of the crosslinking agent were changed as shown in Table 2. . Nisshinbo Carbodilite “V-03” was used as a cross-linking agent composed of a carbodiimide compound.

Examples 11-15
In Example 1, the same operation as in Example 1 was conducted except that instead of toluene, a medium having the composition shown in Table 2 was used as the medium for dissolving the acid-modified ethylene-α-olefin copolymer P-1. To obtain a release sheet.

Comparative Example 2
60.0 g of maleic anhydride-modified polyethylene resin P-9 (manufactured by Arkema, Bondine “LX-4110”), 90.0 g Isopropanol, 3.0 g of triethylamine and 147.0 g of distilled water were charged into a glass container, and the rotation speed of the stirring blade was set to 300 rpm. The system temperature was kept at 140 to 145 ° C., and the mixture was further stirred for 30 minutes. Then, after putting in a water bath and cooling to room temperature (about 25 ° C.) while stirring at a rotational speed of 300 rpm, pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) As a result, a milky white uniform acid-modified polyethylene resin aqueous dispersion E-1 was obtained.
The obtained acid-modified polyethylene resin aqueous dispersion E-1 and the oxazoline compound solution were mixed so that the solid content of the oxazoline compound was 5 parts by mass with respect to 100 parts by mass of the acid-modified polyethylene resin. Performed the same operation as Example 1 to obtain a release sheet.

Comparative Example 3
60.0 g of acid-modified polyisoprene P-10 (manufactured by Kuraray Co., Ltd., Claprene “LIR-403”), 60.0 g of isopropanol, 15 g of triethylamine and 165 g of distilled water were charged into a glass container and heated while stirring at a rotation speed of a stirring blade of 300 rpm, and the system temperature was kept at 120 ° C. and further stirred for 60 minutes. Then, after cooling to room temperature (about 25 ° C.) while stirring with air cooling, pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave), milky white uniform An acid-modified polyisoprene aqueous dispersion was obtained. Except that the obtained acid-modified polyisoprene aqueous dispersion and oxazoline compound solution were mixed so that the solid content of the oxazoline compound was 5 parts by mass with respect to 100 parts by mass of the acid-modified polyethylene resin. The same operation as 1 was performed to obtain a release sheet.

Comparative Example 7
In Example 1, instead of the oxazoline compound solution, a solution obtained by diluting an isocyanate compound (manufactured by BASF, Basonat “HW-100”, solid concentration: 100% by mass) with isopropanol was used, and acid-modified ethylene-α- A release sheet was obtained in the same manner as described above except that the mixture was mixed to 100 parts by mass with respect to 100 parts by mass of the olefin copolymer.

Comparative Example 8
In Example 1, instead of the solution of the oxazoline compound, a solution obtained by diluting an epoxy compound (manufactured by DIC, EPICLON “860-90X”, solid content concentration: 90 mass%) with isopropanol was used, and acid-modified ethylene-α -A release sheet was obtained in the same manner as above except that the mixture was mixed with 100 parts by mass of the olefin copolymer so as to be 5 parts by mass.

Comparative Example 9
In Example 1, instead of the solution of the oxazoline compound, a solution obtained by diluting a melamine compound (Nippon Cytec Industries, Cymel “325”, solid content concentration: 80% by mass) with isopropanol was used. -A release sheet was obtained in the same manner as described above except that the mixture was mixed to 100 parts by mass with respect to 100 parts by mass of the olefin copolymer.

Table 2 shows the evaluation results of the release sheets obtained in the examples and comparative examples.

The release sheet provided with the resin layer containing the acid-modified ethylene-α-olefin copolymer obtained in Examples 1 to 15 and the kind and amount of the crosslinking agent specified in the present invention has a release property, It was excellent in heat resistance, high-speed peelability, and blocking resistance. As shown in Examples 11 to 15, when a mixture of toluene and alcohol or a mixture of toluene and ketone was used as the liquid medium, the coating appearance was excellent. In Example 2, since the mass ratio of the ethylene component and the α-olefin component constituting the acid-modified ethylene-α-olefin copolymer was not in the preferred range, the release property and the high-speed peelability were slightly lowered. In Example 7, the content of the acid-modifying component constituting the acid-modified ethylene-α-olefin copolymer was not in the preferred range, so that the releasability was slightly lowered.

On the other hand, when a resin that does not contain an ethylene component and an α-olefin component at the same time is used as the resin constituting the resin layer (Comparative Examples 1 and 2), the obtained release sheet has a release property and a high-speed release property. It was inferior to. Further, when acid-modified polyisoprene is used as the resin constituting the resin layer (Comparative Example 3), the obtained release sheet has excellent release properties, heat resistance, and residual adhesiveness, but is resistant to blocking. The property decreased significantly.
When a resin that does not undergo acid modification was used as the resin constituting the resin layer (Comparative Example 4), the obtained release sheet was inferior in heat resistance, and the releasability was remarkably lowered by heat treatment.
Even when the resin layer did not contain a cross-linking agent (Comparative Example 5), the release property of the release sheet was remarkably lowered by the heat treatment. Moreover, when there is more content of the crosslinking agent in a resin layer than the range prescribed | regulated by this invention (comparative example 6), the obtained release sheet is inferior to the mold release property in normal temperature, and is further released by heat processing. Decreased.
When a crosslinking agent not specified in the present invention was used (Comparative Examples 7 to 9), the obtained release sheets were inferior in heat resistance, and the releasability was remarkably lowered by heat treatment.

Claims

A release sheet comprising a resin layer provided on a substrate, the resin layer containing 100 parts by mass of an acid-modified ethylene-α-olefin copolymer and 0.1 to 50 parts by mass of a crosslinking agent, A release sheet, wherein the crosslinking agent comprises an oxazoline compound and / or a carbodiimide compound.
The mass ratio (ethylene component / α-olefin component) of the ethylene component and the α-olefin component constituting the acid-modified ethylene-α-olefin copolymer is 60/40 to 99/1. Item 1. The release sheet according to Item 1.
The release sheet according to claim 1 or 2, wherein the α-olefin component is propylene or 1-butene.
The content of the acid-modifying component constituting the acid-modified ethylene-α-olefin copolymer is less than 1% by mass with respect to the total of the ethylene component and the α-olefin component. The release sheet according to any one of 3 above.
The release sheet according to any one of claims 1 to 4, wherein the substrate is any one of a resin material, paper, synthetic paper, cloth, metal material, and glass material.
6. The release sheet according to claim 5, wherein the resin material is a polyester resin film.
The release sheet according to any one of claims 1 to 6, wherein the peel strength between the resin layer and the acrylic adhesive material is 0.5 N / cm or less.