JP2019107824A - Release film and adhesive body - Google Patents

Abstract

To provide a release film excellent in heat resistance, chemical resistance (solvent resistance) and adhesion between a release layer and a base material and having a light peel force.SOLUTION: The release film has a release layer formed on at least one surface of a polyester film in which the release layer is a cured layer of a resin composition containing a nonreactive polyolefin, an acid-modified polyolefin and a crosslinking agent.SELECTED DRAWING: None

Description

The present invention relates to a release sheet which is excellent in heat resistance, chemical resistance (solvent resistance), adhesion between a release layer and a substrate, and in which the pressure-sensitive adhesive layer can be directly coated on the release layer. The present invention also relates to a pressure-sensitive adhesive body in which a pressure-sensitive adhesive layer is provided on a release layer of a release sheet.

Release films are widely used to protect adhesive surfaces or adhesive surfaces. Most commonly used materials for forming the release surface of the release film are silicone polymers containing siloxane units. However, since siloxane-based low-molecular-weight substances are inherent in silicone-based mold release agents, when applied to precision applications such as electronic members, they may volatilize and be oxidized in the air and cause problems due to sticking. there were. Therefore, a film having no siloxane source and having the same releasability as a silicone-based release film has been desired. For example, the hard disk drive has been significantly improved in performance and density, and such performance and density are considered to be further advanced in the future. When the performance and density of the hard disk drive are further increased, it is pointed out that the deposition of the minute silicone compound as described above may adversely affect the reading and writing of the hard disk.

As examples of release layers which contain neither silicon nor halogen elements, polyolefins or long-chain alkyl-containing polymers are also known.
Patent documents 1-6 are mentioned as an example which achieved reduction of exfoliation power using polyolefin. Among them, Patent Document 1 has a problem that the adhesion between the polyolefin and the base film is not sufficient, and the release layer is detached to the adhesive side when the adhesive and the release layer are peeled off. In addition, although polyolefin is good in releasability, heat resistance is not high, so there is a problem that the heat releasability becomes large. Patent documents 2 to 5 improve the adhesion between the polyolefin and the substrate by dissolving the polyolefin in an organic solvent, mixing the polyolefin polyol and the isocyanate crosslinking agent, and applying and drying the mixture. I can not say. Although patent document 6 forms the coating film which consists of acid-modified polyolefin and a crosslinking agent on a base material, peeling property is not enough, adhesiveness of a base material and a release layer, heat resistance, solvent resistance There was no sex assessment.

In a substrate-less adhesive sheet in which a release film is disposed on both sides of an adhesive, or in an adhesive body employing transfer coating, an adhesive solution is coated on the release layer, heated and dried, and then the organic contained in the adhesive solution A pressure-sensitive adhesive layer is provided by evaporating a solvent and performing a chemical reaction of the pressure-sensitive adhesive. However, conventional non-silicone release materials are inferior in chemical resistance (solvent resistance) and heat resistance, or have not achieved low peel strength in the first place, so use substrateless adhesive sheet and transfer coating It has been considered unsuitable for sticky bodies.

JP 2001-246697 A JP, 2011-52207, A JP, 2011-94096, A JP 2012-87210 A JP, 2012-87211, A JP, 2009-101680, A

In view of these problems of the prior art, the present invention has an object to provide a release film which is excellent in heat resistance, solvent resistance, adhesion between a release layer and a substrate, and which has a small peel force. .

As a result of intensive studies to solve the above problems, the inventors of the present invention have found that the release layer of the release film is a cured layer of a resin composition containing a non-reactive polyolefin, an acid-modified polyolefin and a crosslinking agent. It has been found that the above problem is solved.
That is, the gist of the present invention resides in the following.
(1) A release film provided with a release layer on at least one side of a polyester film, wherein the release layer is a cured layer of a resin composition containing a non-reactive polyolefin, an acid-modified polyolefin and a crosslinking agent. Release film characterized by
(2) The release film as described in said (1) whose ethylene unit of the said non-reactive polyolefin is 50 to 80 mass%.
(3) The release film as described in said (1) or (2) whose said non-reactive polyolefin is a copolymer of ethylene and an alpha olefin.
(4) The above-mentioned (non-reactive polyolefin having a density of 0.85 to 0.92 g / cm ³ )
The release film as described in any one of 1)-(3).
(5) The release film according to any one of (1) to (4) above, wherein the acid-modified polyolefin is one modified with maleic anhydride, acrylic acid or methacrylic acid.
(6) The amount of functional groups contained in the acid-modified polyolefin is 0.1 to 5% by mass (1)
The release film as described in any one of-).
(7) The above (1) to (1), wherein the density of the acid-modified polyolefin is 0.94 g / cm ³ or less
(6) Release film (8) according to any one of the above (1) to (7), wherein the crosslinking agent is an epoxy compound.
(9) The adhesive body which laminated | stacked the adhesive layer on the release layer of the release film in any one of said (1)-(8).

According to the present invention, it is possible to provide a release film which is excellent in heat resistance, chemical resistance (solvent resistance), adhesion between a release layer and a substrate, and which has a small peel strength.

<Polyester film>
The polyester film (hereinafter sometimes referred to simply as a base material) in the present invention may have a single-layer structure or a laminated structure of two or more layers. For example, it is possible to change the materials of the surface layer and the intermediate layer to form a three-layer structure in order to effectively improve various characteristics by using highly functional polyester as the surface layer material.

The polyester film in the present invention may be a non-oriented film (sheet) or a stretched film, but is preferably a stretched film, and more preferably a biaxially stretched film.
The polyester used in the present invention may be homopolyester or copolyester. When it consists of homo polyesters, what is obtained by polycondensing aromatic dicarboxylic acid and aliphatic glycol is preferred. Examples of aromatic dicarboxylic acids include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and aliphatic glycols include
Ethylene glycol, diethylene glycol, 1,4-cyclohexanedimethanol and the like can be mentioned. A polyethylene terephthalate etc. are illustrated as a typical polyester. On the other hand, as a dicarboxylic acid component of copolyester, isophthalic acid, phthalic acid,
One or more of terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid and the like can be mentioned, and as a glycol component, ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol,
One or more of neopentyl glycol and the like can be mentioned.

There is no restriction | limiting in particular as a polymerization catalyst of polyester, A conventionally well-known compound can be used, For example, an antimony compound, a titanium compound, a germanium compound, a manganese compound, an aluminum compound, a magnesium compound, a calcium compound etc. are mentioned. Among these, antimony compounds are advantageous in that they are inexpensive and have high catalytic activity.
In the polyester film in the present invention, it is also possible to blend particles mainly for the purpose of imparting slipperiness and preventing the occurrence of flaws in each step. In the case of blending particles, the type of particles to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness, and as specific examples, for example, silica, calcium carbonate, magnesium carbonate, barium carbonate, sulfuric acid Inorganic particles such as calcium, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide and titanium oxide, and organic particles such as acrylic resin, styrene resin, urea resin, phenol resin, epoxy resin and benzoguanamine resin can be mentioned. Furthermore, precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed can also be used in the polyester production process.

On the other hand, the shape of the particles to be used is not particularly limited either, and any of spherical, massive, rod-like, flat and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. These series of particles may be used in combination of two or more as needed.
The average particle diameter of the particles used is preferably 5 μm or less, more preferably 0.1 to 3 μm.
It is the range of m. By using the average particle diameter in the above range, the film can be provided with an appropriate surface roughness, and good slipperiness and smoothness can be ensured.

Furthermore, the particle content in the polyester layer is preferably 5% by mass or less, more preferably 0.
. It is in the range of 0003 to 3% by mass. If there are no particles or if the amount is very small, the transparency of the film will be high and it will be a good film, but since slipperiness may become insufficient, slipperiness can be achieved by putting particles in the coating layer. In some cases, improvements such as improvement are required. When the particle content is too high, the transparency of the film may be insufficient.

It does not specifically limit as method to add particle | grains in a polyester layer, A conventionally well-known method can be employ | adopted. For example, although it can be added at any stage of producing the polyester constituting each layer, it is preferably added after completion of the esterification or transesterification reaction. In addition, the particles may be melt-kneaded and blended with polyester by an extruder or the like.

When the polyester film has a laminated structure of three or more layers, it is also preferable to contain particles only in the surface layer.
In addition to the above-mentioned particles, conventionally known antioxidants, heat stabilizers, lubricants, dyes, pigments and the like can be added to the polyester film in the present invention, as needed.
The thickness of the polyester film in the present invention is not particularly limited as long as the film can be formed as a film, but is preferably 5 to 300 μm, more preferably from the viewpoint of mechanical strength, handling and productivity. Is in the range of 10 to 125 μm.

Next, although the manufacturing example of the polyester film in this invention is concretely demonstrated, it is not limited at all to the following manufacturing examples. That is, it is preferable to extrude the pellets obtained by drying the polyester raw material described above from a die as a molten sheet using an extruder and to cool and solidify with a cooling roll to obtain an unstretched sheet. In this case, in order to improve the planarity of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum.
Alternatively, a liquid coating adhesion method is preferably employed. Next, the obtained unstretched sheet is biaxially stretched. In that case, first, the unstretched sheet is stretched in one direction by a roll or tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Then, the film is stretched in the direction orthogonal to the first-stage stretching direction, in which case the stretching temperature is usually 70 to 170 ° C., and the stretching ratio is usually 3.0 to 7 times, preferably 3.5 to 6 times is there. And continue 18
Heat treatment is performed at a temperature of 0 to 270 ° C. under tension or relaxation within 30% to obtain a biaxially oriented film. In said extending | stretching, the method of performing extending | stretching of one direction in two or more steps is also employable. In that case, it is preferable to carry out so that the draw ratio of two directions finally becomes the said range, respectively.

In the present invention, simultaneous biaxial stretching can also be employed for polyester film production. The simultaneous biaxial stretching method is a method of simultaneously stretching and orienting the above-mentioned unstretched sheet in the machine direction and the width direction in a state where the temperature is usually controlled at 70 to 120 ° C., preferably 80 to 110 ° C. Is 4 to 50 times in area magnification, preferably 7 to 3
It is 5 times, preferably 10 to 25 times. Then, heat treatment is subsequently performed at a temperature of 170 to 250 ° C. under tension or relaxation within 30% to obtain a stretched and oriented film. As for the simultaneous biaxial stretching apparatus adopting the above-mentioned stretching method, a screw method, a pantograph method,
A conventionally known stretching method such as a linear drive method can be employed.

Furthermore, a so-called coating and drawing method (in-line coating) can be applied to treat the film surface during the above-described polyester film drawing step. In the case where the coating layer is provided on the polyester film by the coating and drawing method, the coating can be performed simultaneously with the drawing, and the thickness of the coating layer can be reduced according to the draw ratio to produce a suitable release film. be able to.

In addition, the "polyester film" which comprises the release film of this invention does not mean only what was shape | molded beforehand as a film, and the polyester layer should just be comprised in the release film. That is, "polyester film" is synonymous with "polyester layer." Therefore, not only the aspect which laminates a mold release layer on the surface of a polyester film, it can also be set as a polyester film by co-extrusion molding of a polyester layer and a mold release layer.

<Composition for Release Layer Formation>
(Non-reactive polyolefin)
The non-reactive polyolefins used in the present invention are polyolefins which have substantially no reactivity. More specifically, it means a polyolefin which does not have reactivity with a crosslinking agent. The nonreactive polyolefins may be used alone or in combination of two or more. It is preferable to use a polyethylene copolymer from the viewpoint of releasability and heat resistance.

When using a polyethylene copolymer, it is preferable to use what was synthesize | combined using transition metal catalysts, such as a Ziegler Natta catalyst and a metallocene catalyst. Among them, use of one synthesized using a metallocene catalyst has an advantage that a release film having excellent release property and heat resistance can be obtained. Specific examples of the polyethylene copolymer include ethylene-propylene copolymers, ethylene-hexene copolymers, ethylene-butene copolymers, ethylene-octene copolymers, and copolymers of ethylene and α-olefins. It can be mentioned.

The density of the nonreactive polyolefin is not particularly limited, but is preferably 0.92 g / cm ³ or less, and more preferably 0.90 g / cm ³ or less. Also, the density of the nonreactive polyolefin is usually 0.85 g / cm ³ or more. When the density of the nonreactive polyolefin is in the above range, releasability tends to be good.
The content of ethylene units contained in the non-reactive polyolefin is not particularly limited, but 50
% By mass or more and 80% by mass or less is preferable. When the content of the ethylene unit is 80% by mass or less, the generation of gel during coating is small, the pressure increase of the filter and the deterioration of the appearance of the release film are suppressed, and the productivity tends to be good. Further, when the content of the ethylene unit is 50% by mass or more, sufficient releasability tends to be obtained.

In the present invention, when only one non-reactive polyolefin is used, the non-reactive polyolefin has a MFR (melt flow rate) at 230 ° C. and a load of 2.16 kg from the viewpoint of coating film strength at the time of forming a release layer. Those having 100 g / 10 min or less are preferable, those having MFR 70 g / 10 min or less are more preferable, those having MFR 50 g / 10 min or less are still more preferable, and MFR is 10 g / 10 min or less Is particularly preferred. The lower limit is not particularly limited, but is usually 0.2 g / 10 min or more.

When two or more non-reactive polyolefins are used, it is preferable to use one having MFR of 100 g / 10 min or less at 230 ° C. and a load of 2.16 kg at least one of them, and in the release layer. The proportion of the polyolefin having an MFR of 100 g / 10 minutes or less is preferably 10% by mass or more, and more preferably 50% by mass or more.
If this condition is satisfied, the other polyolefin is M at 230 ° C. under a load of 2.16 kg.
One having an FR of more than 100 g / 10 min may be used.

The content of the non-reactive polyolefin in the composition for forming a release layer is preferably 80 to 99% by mass, more preferably 90 to 99% by mass. When the content is 80% by mass or more, the removability tends to be good and the releasability tends to be small, and by being 99% by mass or less,
There is a tendency for sufficient coating strength to be obtained without excessively reducing the amount of components to be crosslinked.

(Acid-modified polyolefin)
The acid-modified polyolefin used in the present invention reacts with the crosslinking agent to form a three-dimensional network. Through such a crosslinking reaction, heat resistance and chemical resistance (solvent resistance) can be imparted to the release layer.
The acid-modified polyolefin is prepared by using ethylene and one or more .alpha.
It is preferable to be comprised by the unit which consists of olefins. Examples of α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene etc. are mentioned. Among these, propylene or 1-butene is preferable from the viewpoint of economy and availability.

The mass ratio of ethylene units in the acid-modified polyolefin is 50% by mass or more and 80% by mass
The following are preferable, More preferably, they are 60 mass% or more and 75 mass% or more. When the ethylene component is 50% by mass, the releasability tends to be good, and when it is 80% by mass or less, gelation during coating tends to be small.
Acid-modified polyolefins that can be used in the present invention include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic acid, aconitic acid, aconitic acid, aconitic acid anhydride, fumaric acid, crotonic acid, citraconic acid, mesaconic acid, allyl succinic acid Examples thereof include compounds having at least one carboxyl group or acid anhydride group in the molecule (within the monomer unit), such as polyolefins modified with acid or the like, half esters of unsaturated dicarboxylic acids, half amides and the like. From the viewpoint of availability, polyolefin modified with maleic anhydride, acrylic acid or methacrylic acid is preferred, and maleic anhydride modified polyolefin is more preferred.

Examples of commercially available acid-modified polyolefins include Modic series manufactured by Mitsubishi Chemical Co., Ltd., and MP-0620, MH-7020, and MA-8510 of Tafmar series manufactured by Mitsui Chemicals, Inc.
In order to achieve both low peel strength and adhesion to a substrate, the amount of functional groups contained in the acid-modified polyolefin is preferably 0.1 to 5% by mass, and 0.5 to 3% by mass. More preferable. By being the said range, there exists a tendency for peeling force to be small, and the adhesiveness of a base material and a mold release layer to become favorable. The amount of functional groups as referred to herein means the content of carboxyl group and acid anhydride group, and does not include other functional groups.

The lower the density of the acid-modified polyolefin, it is possible to reduce the impact on the peel strength, density is preferably 0.94 g / cm ³ or less, more preferably 0.90 g / cm ³ or less. On the other hand, the lower limit is not particularly limited, but is preferably 0.80 g / cm ³ or more.
Acid-modified polyolefins have a load of 2.1 at a temperature of 230 ° C. from the viewpoint of coating film strength at the time of forming a release layer.
The MFR (melt flow rate) at 6 kg is preferably 100 g / 10 min or less, more preferably 70 g / 10 min or less, and even more preferably 50 g / 10 min or less. Particularly preferred is one having 10 g / 10 minutes or less. On the other hand, the lower limit is not particularly limited, but is usually 0.2 g / 10 min or more.

The acid-modified polyolefin may have a functional group other than a carboxyl group or an acid anhydride group in the molecule, for example, a hydroxyl group, an amino group, an epoxy group, a vinyl group, a glycidyl group and the like. The acid-modified polyolefin used in the present invention may be a composition comprising a plurality of acid-modified polyolefins.
Moreover, in this invention, content of the acid modified polyolefin in the composition for mold release agent formation becomes like this. Preferably it is 1-40 mass%, More preferably, it is 3-30 mass%. When the content is 1% by mass or more, the heat resistance and the solvent resistance tend to be good. Moreover, there exists a tendency for peeling force to become small because it is 40 mass% or less.

(Crosslinking agent)
The crosslinking agent is a compound having two or more functional groups capable of reacting with the acid-modified polyolefin in one molecule. Reactive polyolefins having functional groups that can react with acid-modified polyolefins can also be used as crosslinkers.
The crosslinking agent is a compound having the function of forming a network by dispersing or compatibilizing in an acid-modified polyolefin in the micro, and crosslinking with the acid-modified polyolefin, thereby improving heat resistance and chemical resistance. . The crosslinking agent is preferably a compound which also has the function of reacting or interacting with functional groups present on the surface of the substrate to improve adhesion to the substrate.

As a crosslinking agent, it is possible to use conventionally well-known various crosslinking agents, for example, a melamine compound, an oxazoline compound, an epoxy compound, a carbodiimide type compound, a silane coupling compound etc. are mentioned. Among these, isocyanate is particularly preferable from the viewpoint of the reactivity with the acid-modified polyolefin. Specific examples include tetramethylene diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthyl diisocyanate, tolidine diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogen And polyfunctional isocyanates such as hydrogenated diphenylmethane diisocyanate, dimer acid diisocyanate, norbornene diisocyanate, trans-cyclohexane diisocyanate, hydrogenated tolylene diisocyanate and adducts thereof, polyhydric alkylamines and compositions thereof. From the viewpoint of the strength and heat resistance of the release layer, an isocyanate having two or more isocyanate groups in one molecule is preferable.

From the viewpoint of adhesion of the release layer and heat resistance, epoxy compounds are preferred. As a specific example,
N, N, N ', N'-tetraglycidyl-m-xylenediamine, diglycidyl aniline, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane (Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C" ), 1,6-Hexanediol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 1600"), neopentyl glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 1500 NP"), ethylene glycol diglycidyl ether (Kyoeisha Chemical Co., Ltd., trade name "Epolight 40E"), Propylene glycol diglycidyl ether (Kyoeisha Chemical Co., Ltd., trade name "Epolight 70P"), polyethylene glycol diglycidyl ether (Nippon Yushi Co., Ltd., trade name "Epiol E- 400 "
), Polypropylene glycol diglycidyl ether (manufactured by Nippon Oil and Fats Co., Ltd., trade name "Epiol P-200"), sorbitol polyglycidyl ether (manufactured by Nagase ChemteX, trade name "Denacol EX-611"), glycerol polyglycidyl ether (Nagase) Chemtex, trade name "Denacol EX-314"), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX, trade name "Denacol EX-512"), sorbitan polyglycidyl ether, trimethylol Propane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl tris (2-hydroxyethyl) isocyanurate, resorcin diglycidyl Ether, bisphenol -S- diglycidyl ether, epoxy resins having two or more epoxy groups in the molecule.

Content of the crosslinking agent in the composition for mold release layer formation (mold release layer before hardening) is 0.5-20 mass%, Preferably it is 0.5-10 mass%. When the content is 0.5% by mass or more, sufficient heat resistance and solvent resistance tend to be obtained. Moreover, there exists a tendency for peelability to become favorable and peel force to become small because content is 20 mass% or less.

(Other ingredients)
The composition for forming a release layer according to the present invention may further contain, if necessary, an olefin resin other than the above nonreactive polyolefin and reactive polyolefin, paraffin, paraffin wax, process oil, antioxidant, UV absorber, Light stabilizers such as hindered amine light stabilizers and antistatic agents, fillers such as carbon black, calcium oxide, magnesium oxide, silica, zinc oxide and titanium oxide, pigments, catalysts and the like may be appropriately blended.

A catalyst may be added to the composition for forming a release layer used for producing the release film of the present invention in order to accelerate the reaction of the release layer. Although the type of the catalyst is not particularly limited, it is preferable to use a curing catalyst in order to accelerate the reaction of the acid-modified polyolefin contained in the composition for release layer formation and the crosslinking agent.
As a curing catalyst in the case of using an isocyanate as a crosslinking agent, tertiary amines, carboxylates of tertiary amines, metal salts of carboxylic acids (such as potassium acetate, potassium octylate and stannas octoate) and organometallic compounds (dibutyltin) Dilaurate etc., and tertiary amines are preferred.

Examples of tertiary amines include N-ethylmorpholine, N-methylpiperidine, pyrrolidine, quinuclidine, 1,4-diazabicyclo [2.2.2] octane, diethylethanolamine, N, N, N ', N'-. Tetramethylhexamethylenediamine, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1,8-diazabicyclo- [5,4,0] -undecene-7 (carboxylate) and bis (dimethylaminoethyl) )
Ethers (carboxylates) as well as combinations of two or more of these can be mentioned.

Moreover, as a curing catalyst in the case of using an epoxy compound as a crosslinking agent, tertiary amines such as benzyldimethylamine, tris (dimethylamine methyl) phenol and dimethylcyclohexylamine; 2-ethyl-4-methylimidazole, 2- Methyl imidazole,
Imidazoles such as 1-benzyl-2-methylimidazole; 1,8-diazabicyclo [
5.4.0] Diazabicycloalkenes such as undecene-7 and 1,4-diazabicyclo [2.2.2] octane and salts thereof; Organics such as zinc octylate, tin octylate and aluminum acetylacetone complex Metal compounds; organic phosphine compounds such as triphenylphosphine etc .; quaternary ammonium compounds etc. may be mentioned.
The content of the curing catalyst is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, and still more preferably 0.05% by mass or more from the viewpoint of promoting reaction. On the other hand, 5 mass% or less is preferable, 4 mass% or less is more preferable, and 3 mass% or less is more preferable.

<Release film>
The release film of the present invention is provided with a release layer on at least one side of a polyester film, but the method of laminating the release layer is not limited. Specifically, the composition constituting the release layer is dissolved in a diluting solvent, and the solution is applied to a substrate and then dried. Although the solution concentration (solid content concentration) is not particularly limited, it is usually adjusted in the range of 0.1 to 5% by mass.

The dilution solvent is not particularly limited as long as the composition for forming a release layer can be uniformly dissolved or suspended and dispersed, but since the release agent in the present invention is mainly composed of polyolefin, it is mainly a hydrocarbon solvent. It is preferable to use it from the viewpoint of uniformly dissolving or suspending it. Examples of hydrocarbon solvents include aliphatic hydrocarbon solvents such as normal hexane and normal heptane, alicyclic hydrocarbon solvents such as cyclohexane, and aromatic hydrocarbon solvents such as toluene and xylene. If necessary, ketones such as methyl ethyl ketone, cyclohexanone and acetylacetone, esters such as ethyl acetate, and alcohols such as methanol, ethanol and isopropyl alcohol may be used in combination.

In addition, as a method for applying the composition for forming a release layer to a substrate, known and commonly used methods such as a kiss roll coater, a bead coater, a rod coater, a Mayer bar coater, a die coater, and a gravure coater can be used. The drying method is also not particularly limited, but the most common method is hot air drying, and depending on the heat resistance of the substrate, the release layer can be obtained by drying at a temperature of about 80 to 150 ° C.
The thickness of the release layer is preferably 30 to 500 nm, more preferably 45 to 400 nm
, Most preferably 60 to 300 nm. If the thickness of the release layer is less than 30 nm, the peeling force may increase, and if it exceeds 500 nm, blocking may occur when the film is wound in a roll, or the peeling force may increase.

<Adhesive body>
The present invention provides a pressure-sensitive adhesive body in which a pressure-sensitive adhesive layer is laminated on a release layer of a release film.
The pressure-sensitive adhesive used for the pressure-sensitive adhesive layer of the pressure-sensitive adhesive body is not particularly limited, and rubber-based, acrylic-based, polyester-based pressure-sensitive adhesives and the like can be mentioned. It is preferable because the property is obtained.

Acrylic-based pressure-sensitive adhesives mainly contain acrylic polymers obtained by conventional polymerization methods such as solution polymerization method, emulsion polymerization method and UV polymerization method, and if necessary, crosslinking agents, tackifiers, softeners, anti-aging agents It can be prepared by adding various additives such as agents and fillers.
As the acrylic polymer, for example, alkyl (meth) acrylate such as butyl (meth) acrylate or 2-ethylhexyl (meth) acrylate as a main component, and as a copolymerizable modifying monomer if necessary, 2-hydroxyethyl ( Hydroxy group-containing monomers such as (meth) acrylate, carboxy group-containing monomers such as (meth) acrylic acid,
A copolymer of a monomer mixture to which another monomer such as a styrene-based monomer such as styrene or a vinyl ester such as vinyl acetate is added is used.

In addition, as polyester-based pressure-sensitive adhesives, polyester-based weights containing an aliphatic carbonate diol (for example, a carbonate diol obtained by the reaction of a diol component such as butanediol and a carbonate compound such as ethylene carbonate) as an essential polyol component The adhesive which makes a combination the main ingredient is mentioned.
The pressure-sensitive adhesive layer can be formed, for example, by applying a solution containing a pressure-sensitive adhesive on the release layer of the release film and drying it. The thickness of the pressure-sensitive adhesive layer can be appropriately selected in consideration of adhesiveness and the like, and is usually 3 to 100 μm, preferably 5 to 90 μm, and more preferably 10 to 80 μm.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Moreover, the measuring method used by this invention is as follows.

(1) Measurement of Intrinsic Viscosity of Polyester Weigh precisely 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed, and add 100 ml of mixed solvent of phenol / tetrachloroethane = 50/50 (mass ratio) It was dissolved and measured at 30 ° C.

(2) Measurement of average particle diameter (d50: μm) 50% of integration (mass standard) in equivalent spherical distribution measured using a centrifugal sedimentation type particle size distribution measuring apparatus (SA-CP type 3 manufactured by Shimadzu Corporation) The value was taken as the average particle size.

(3) Evaluation of Normal Peeling Force of Releasing Film After pasting one side of double-sided adhesive tape (“No. 31 B” made by Nitto Denko) on the surface of releasing layer of sample film, after cutting into 50 mm × 300 mm size Measure the peel force after standing for 1 hour at room temperature. Peeling force can be measured using a tensile tester (Intesco Model Intesco Model 20
Using a 01 type), 180 ° peeling was performed under a tensile speed of 300 mm / min, and the normal peeling force (A) was measured.

(4) Evaluation of thermal peeling force of mold release film After affixing one side of double-sided adhesive tape ("No. 31 B" made by Nitto Denko) on the surface of mold release layer of sample film, after cutting into a size of 50 mm x 300 mm It was left to stand at 100 ° C. for 1 hour, and the peeling force after cooling to normal temperature (23 ° C.) was measured. The peeling force was measured using a tensile tester (“Intesco model 2001 type” manufactured by Intesco Corporation) under conditions of a tensile speed of 300 mm / min.
Peeling was performed at 180 °, and the thermal peeling force (B) was measured.

(5) Evaluation of peeling force after solvent treatment and solvent treatment of release film 10 cellulose non-woven wipers in which 4 ml of toluene was impregnated on the surface of the release layer of the sample film using a rubbing tester made by Taiheisei Kogyo Co., Ltd. 10 Then it was reciprocated, then air-dried, and an adhesive tape (Nitto Denko "No. 31 B") was attached. After cutting this into a size of 50 mm × 300 mm, the peeling force after leaving at room temperature for 1 hour was measured. Peeling force performs 180 ° peeling using a tensile tester (Intesco Model 2001 type manufactured by Intesco Co., Ltd.) under conditions of 300 mm / min tensile speed, and the peeling force after solvent treatment (C) It was measured.
The solvent resistance was compared by determining the ratio ((C) / (A)) of the peel strength (C) after the solvent treatment and the normal-state peel strength (A). The smaller the value of (C) / (A), the smaller the change in peel force from the normal peel force, suggesting that the solvent resistance is higher.

(6) Evaluation of base material adhesion of release layer of release film (evaluation of practical characteristics)
The release surface of the sample film immediately after coating was rubbed 20 times with a feeler, and the degree of release of the release layer was determined according to the following determination criteria.
Judgment criteria
○: no detachment of the coating was observed, or the coating became white, but not (practical use)
X: Dropping of the coating film was confirmed (practical difficulty)
The materials used in the examples and comparative examples were prepared as follows.

[Raw material of base material]
Polyester A:
Polyethylene terephthalate homopolymer chip (Inherent viscosity: 0.66 dl / g)
Polyester B:
Chip of polyethylene terephthalate homopolymer containing 1000 ppm of amorphous silica having an average particle diameter of 2 μm (Intrinsic viscosity: 0.62 dl / g)

[Raw material for release layer]
<Non-reactive polyolefin>
Ethylene-propylene copolymer B1:
Ethylene-Propylene Random Copolymer ( ¹ H-NM) Obtained by Metallocene Catalyst
Composition mass ratio by R: ethylene / propylene = 74/26, MFR (230 ° C., load 2.
16 kg) 2.0 g / 10 min, density 0.86 g / cm ³ ).
Ethylene-propylene copolymer B2:
Ethylene-Propylene Random Copolymer ( ¹ H-NM) Obtained by Metallocene Catalyst
Composition mass ratio by R: ethylene / propylene = 51/49, MFR (230 ° C., load 2.
16 kg) 2.0 g / 10 min, density 0.86 g / cm ³ ).
Ethylene-propylene copolymer B3:
Ethylene-Propylene Random Copolymer ( ¹ H-NM) Obtained by Metallocene Catalyst
Composition mass ratio by R: ethylene / propylene = 47/53, MFR (230 ° C., load 2.
16 kg) 2.0 g / 10 min, density 0.86 g / cm ³ ).
· Ethylene-hexene copolymer C1:
Ethylene-Hexene Random Copolymer ( ¹ H-NMR) Obtained by Metallocene Catalyst
Composition mass ratio by: ethylene / hexene = 76/24, MFR (230 ° C., load 2.16)
kg) 3.5 g / 10 min).
· Ethylene-hexene copolymer C2:
Ethylene-Hexene Random Copolymer ( ¹ H-NMR) Obtained by Metallocene Catalyst
Composition mass ratio according to: ethylene / hexene = 85/15, MFR (230 ° C., load 2.16)
kg) 7 g / 10 min).

<Reactive polyolefin>
・ Mitsubishi Chemical Co., Ltd., Polytail H (Hydride of polybutadiene having hydroxyl group, number average molecular weight 2700, OH group content 1.5 mass% determined by NMR, density 0.85 g / cm ³ )
<Acid-modified polyolefin>
· Mitsui Chemicals, Inc. Tafmer MA 8510 (maleic anhydride-modified ethylene-propylene copolymer, density 0.885 g / cm ³ , MFR (230 ° C., load 2.16 kg) 5 g / 10)
Minutes)

<Trifunctional isocyanate>
Aliphatic trifunctional isocyanate / triol adduct, manufactured by Mitsubishi Chemical Corporation,
Mitec NY 718A (75% by mass butyl acetate solution)
Mitsui Chemicals, Inc., alicyclic trifunctional isocyanate / trimethylolpropane adduct
Takenate D 120 N (75% by mass ethyl acetate solution)
<Epoxy compound>
Nagase ChemteX, Multifunctional Epoxy Compound Denacol EX-614B
<Curing catalyst>
Wako Pure Chemical Industries, Ltd., 1,4-diazabicyclo [2,2,2] octane

Example 1:
(Preparation of base material)
The polyester A is a raw material for the intermediate layer, and the polyester B is a raw material for the surface layer,
Each raw material is melt-extruded by a separate melt extruder, and the sheet is coextrusion-cooled and solidified on a casting drum on which the amorphous sheet of two types and three layers of surface layer / interlayer / surface layer is cooled, and non-oriented sheet is obtained. Obtained.

Then, it was stretched 3.4 times at 90 ° C. in the machine direction (longitudinal direction). In addition 12 in the tenter
After the 0 ° C. preheating step, the film was stretched 4.1 times in the width direction (lateral direction) and heat-treated at 230 ° C. for 3 seconds to obtain a polyester film as a substrate. The thickness of the obtained polyester film was 38 μm, and the thickness configuration of the surface layer / intermediate layer / surface layer was 3 μm / 32 μm / 3 μm.

By heating each of ethylene-propylene copolymer B2, ethylene-hexene copolymer C1, and Tafmer MA 8510 with toluene, a 2% concentration toluene solution was obtained. The composition in the solid content of the composition for forming a mold release layer (hereinafter sometimes abbreviated as mold release agent) is ethylene-propylene copolymer B2 / ethylene-hexene copolymer C1 / Tafmer MA8510 / Denacol EX 614B / The mixture was mixed so that 1,4-diazabicyclo [2,2,2] octane = 40/40/17/2/1 (mass ratio) to obtain a releasing agent liquid. The release agent liquid was applied to the polyester film obtained above by a Meyer bar and dried for 30 seconds with a dryer at 150 ° C. to obtain a release film having a release layer with a thickness of 0.2 μm.

Example 2:
Ethylene-propylene copolymer B2 / Tafmer MA 8510 composition of solid content of mold release agent
/ Takenate D 120 N / 1,4-diazabicyclo [2,2,2] octane = 80/17
A release film was produced in the same manner as in Example 1 except that the ratio was set to 1/21 (mass ratio).

Example 3:
Ethylene-propylene copolymer B1 / Tafmer MA 8510 composition of solid content of mold release agent
/ Denacol EX 614 B / 1,4-Diazabicyclo [2,2,2] octane = 50/4
A release film was produced in the same manner as in Example 1 except that the ratio was 4/5/1 (mass ratio).

Example 4:
The composition of the solid content of the releasing agent was ethylene-hexene copolymer C1 / Tafmer MA8510 /
Denacol EX 614 B / 1,4-Diazabicyclo [2,2,2] octane = 60/35
A release film was produced in the same manner as in Example 1 except that the ratio was changed to / 4/1 (mass ratio).

Example 5:
Ethylene-propylene copolymer B1 / ethylene-hexene copolymer C2 / tafmer MA8510 / denacol EX 614B / 1,4-diazabicyclo [2,2,2] octane = 20/20/20 A release film was produced in the same manner as in Example 1 except that the ratio was 53/6/1 (mass ratio).

Comparative Example 1:
A release film was produced in the same manner as in Example 1 except that the composition in the solid content of the release agent was changed to ethylene-propylene copolymer B1 = 100.

Comparative example 2:
Toughmer MA 8510 / Denacol EX 614 B / 1, 4 in solid content of mold release agent
A release film was produced in the same manner as in Example 1 except that diazabicyclo [2,2,2] octane = 89/10/1 (mass ratio).

Comparative example 3:
The composition of the solid content of the releasing agent was ethylene-propylene copolymer B3 / polytail H / mitech NY 718A / 1,4-diazabicyclo [2,2,2] octane = 80/17/2 /
A release film was produced in the same manner as in Example 1 except that 1 (mass ratio) was used.
Table 1 shows the evaluation results of the release film prepared in the example and the comparative example.

As in Examples 1 to 5, the adhesion to the substrate is good and the peeling force is small, and the peeling force is relatively small after heating and after the solvent treatment, and the peeling force (C) and the normal state peeling force (A) after the solvent treatment Ratio ((C) / (
A) A) was small, and the solvent resistant high release film was able to be created. In Comparative Example 1, the release layer was made of the composition for forming a release layer containing no acid-modified polyolefin and no crosslinker.
It is suggested that the adhesion to a substrate is insufficient, the peel strength after heat peeling and after solvent treatment is large, and the heat resistance and solvent resistance are insufficient. In Comparative Example 2, the heat release strength exceeds 200 mN / cm because the release layer is made of the composition for forming a release layer which does not contain a nonreactive polyolefin although the above (C) / (A) is relatively small. It is suggested that heat resistance is insufficient. Although the comparative example 3 used the reactive polyolefin which has a hydroxyl group instead of acid-modified polyolefin, the adhesiveness of a mold release layer and a base material is inadequate, and the normal-state peeling force became large.

Claims (9)

A release film provided with a release layer on at least one side of a polyester film, wherein the release layer is a cured layer of a resin composition containing a non-reactive polyolefin, an acid-modified polyolefin and a crosslinking agent. Release film. The release film according to claim 1, wherein the ethylene unit of the nonreactive polyolefin is 50% by mass or more and 80% by mass or less. The non-reactive polyolefin is a copolymer of ethylene and an α-olefin.
Or the release film as described in 2. The density of the non-reactive polyolefin is 0.85 to 0.92 g / cm ³ .
The release film of any one of 3. The release film according to any one of claims 1 to 4, wherein the acid-modified polyolefin is one modified with maleic anhydride, acrylic acid or methacrylic acid. The amount of functional groups contained in the acid-modified polyolefin is 0.1 to 5% by mass.
The release film according to any one of the above. The density of the said acid modified polyolefin is 0.94 g / cm < ³ > or less, The release film of any one of Claims 1-6. The release film according to any one of claims 1 to 7, wherein the crosslinking agent is an epoxy compound. The adhesive body which laminated | stacked the adhesive layer on the release layer of the release film of any one of Claims 1-8.