JP2020122069A - Thermosetting release coating agent and release film - Google Patents

Abstract

To provide a novel thermosetting release coating agent making it possible to form a cured film that is excellent in coating appearance, peeling performance and solvent resistance.SOLUTION: A thermosetting release coating agent includes polyol (A), a self-condensation product (B) of aliphatic hydroxycarboxylic acid (b) having a carbon number of 12 to 24, and polyisocyanate (C).SELECTED DRAWING: None

Description

The present invention relates to a thermosetting release coating agent and a release film.

A biaxially stretched polyester film represented by a polyethylene terephthalate film is excellent in performances such as transparency, dimensional stability, mechanical properties, and chemical resistance, and is used in various industrial fields. In recent years, it has been widely used for various optical films, and has been used for various applications such as a prism sheet of an LCD member, a light diffusion sheet, a reflection plate, a base film for a touch panel, a base film for antireflection, and the like. Further, it is often used as a base film of a release film, and is widely used for electronic materials such as production of adhesive sheets/adhesive tapes, protective films for touch panels and ceramic green sheets.

The conventional release film is mainly one in which a release layer made of a resin coating film of a silicone resin-based release agent having release properties is formed on the surface of a polyester film. However, when the resin coating film is formed using a silicone-based release agent, the low molecular weight silicone compound derived from the silicone-based release agent may migrate from the resin coating film to the surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet. Therefore, it has been pointed out that the adhesive strength of the pressure-sensitive adhesive layer may be reduced and that the electronic component bonded by this pressure-sensitive adhesive sheet may cause a trouble. Also, in the release film used in the manufacturing process of ceramic green sheets for capacitors and printed circuit boards, the sealing process of various electronic components, etc., similarly, the silicone compound migrates to the surface of the electronic components, which causes a problem. Was pointed out.

A non-silicone release agent has been proposed in order to suppress contamination by the silicone compound (see Patent Documents 1 and 2). Patent Documents 1 and 2 disclose a non-silicone release agent containing a long-chain alkyl pendant polymer obtained by reacting polyvinyl alcohol or ethylene-vinyl alcohol copolymer with a long-chain alkyl isocyanate.

JP 2000-119608 A JP-A-5-295332

However, the release agents disclosed in the above Patent Documents 1 and 2 have a problem that the coating film formed from the release agent has low solvent resistance, although the release performance is good. Further, since the above-mentioned release agent has low solubility in various solvents, the coating film formed from the release agent is liable to have defects in appearance such as white turbidity or unevenness, and there is also a problem that the coating film appearance is poor. ..

An object of the present invention is to provide a novel thermosetting release coating agent capable of forming a cured film having an excellent coating film appearance and excellent release performance and solvent resistance.

As a result of intensive studies, the present inventors have found that the above problems can be solved by a composition containing a polyol, a predetermined self-condensation product of an aliphatic hydroxycarboxylic acid, and a polyisocyanate, and have completed the present invention. That is, the present invention relates to the following thermosetting release coating agent and release film.

1. A thermosetting release coating agent containing a polyol (A), a self-condensate (B) of an aliphatic hydroxycarboxylic acid (b) having 12 to 24 carbon atoms, and a polyisocyanate (C).

2. The thermosetting release coating agent according to item 1, wherein the hydroxyl value of the component (A) is 50 to 500 mgKOH/g.

3. Item 3. The thermosetting release coating agent according to Item 1 or 2, wherein the component (B) is a self-condensation product of an aliphatic hydroxycarboxylic acid having 18 carbon atoms.

4. The thermosetting release coating according to any one of Items 1 to 3, wherein the content of the component (B) is 1 to 30% by mass based on 100% by mass of the total solid content of the thermosetting release coating agent. Agent.

5. The thermosetting release coating agent according to any one of Items 1 to 4, wherein the component (C) is a polyisocyanate having at least 3 isocyanate groups in the molecule.

6. Item 6. The heat according to any one of Items 1 to 5, wherein the molar ratio (NCO/OH) of the isocyanate group contained in the component (C) and the hydroxyl group contained in the component (A) is 0.3 to 3.0. Curable release coating agent.

7. Furthermore, the thermosetting release coating agent in any one of said claim|item 1-6 containing a hardening catalyst (D).

8. A release film comprising a cured film comprising the thermosetting release coating agent according to any one of Items 1 to 7 and a plastic film.

9. Item 9. The release film according to Item 8, wherein the plastic film is a polyethylene terephthalate film.

The thermosetting release coating agent of the present invention has a light release force and can form a cured film having excellent solvent resistance by heat drying for a short time (rapid curing). Further, the cured film formed from the coating agent is transparent and smooth and has an excellent coating film appearance. Further, the coating agent is suitable as a release agent for a release film whose base film is a polyester film.

The thermosetting release coating agent (hereinafter referred to as a coating agent) of the present invention is a self-condensate of a polyol (A) (hereinafter referred to as a component (A)) and an aliphatic hydroxycarboxylic acid (b) having 12 to 24 carbon atoms ( It is a composition containing B) (hereinafter referred to as “component (B)”) and polyisocyanate (C) (hereinafter referred to as “component (C)”).

As the component (A), various known compounds can be used without particular limitation as long as they are compounds having at least two hydroxyl groups (—OH) in the molecule.

Examples of the component (A) include a polyol (a1) as a single compound (hereinafter referred to as a component (a1)) and/or a polyol (a2) as a polymer (hereinafter referred to as a component (a2)).

As the component (a1), various known ones can be used without particular limitation. Specifically, for example, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 2-methyl-1,5-pentanediol, 2,2-diethyl-1,3- Aliphatic diols such as propanediol, 1,9-nonanediol, 1,10-decanediol, butylethylpropanediol, butylethylpentanediol; alicyclic diols such as 1,4-cyclohexanedimethanol; trimethylolpropane, Pentaerythritol, ditrimethylolpropane, dipentaerythritol, dimer diol, hydrogenated dimer diol, trimer triol, hydrogenated trimer triol, castor oil, castor oil-based modified polyol, alkylene oxide adduct of bisphenol compound or its derivative, and the like. , One kind may be used alone, or two or more kinds may be used in combination.

As the component (a2), various known ones can be used without particular limitation. Specific examples include at least one selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, acrylic polyol, polyolefin polyol and the like.

Polyether polyols include, for example, polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, as well as a plurality of alkylene oxides as monomer components such as ethylene oxide-propylene oxide copolymers (alkylene oxide-others). The alkylene oxide) copolymer and the like are listed, and one kind can be used alone or two or more kinds can be used in combination. Commercially available products are, specifically, Adeca polyether P-400, Adeca polyether P-700, Adeca polyether P-1000, Adeca polyether P-2000, Adeca polyether G-400, Adeca polyether G-700. , Adeka polyether G-1500, Adeka polyether G-3000B, Adeka polyether T-400, Adeka polyether AM-302 (above, manufactured by ADEKA), PTMG650, PTMG850, PTMG1000, PTMG1300, PTMG1500, PTMG1800, PTMG2000 (above, Mitsubishi Chemical Corporation make) etc. are mentioned.

Examples of the polyester polyol include a condensation polymerization product of a polyhydric alcohol and a polycarboxylic acid; a ring-opening polymer of a cyclic ester (lactone); a three-way reaction product of a polyhydric alcohol, a polycarboxylic acid and a cyclic ester. To be Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, 3-methyl. -1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, glycerin, trimethylolpropane, trimethylolethane, cyclohexanediols (1,4 -Cyclohexanediol, etc.), cyclohexanedimethanols (1,4-cyclohexanedimethanol, etc.), bisphenols (bisphenol A, etc.), sugar alcohols (xylitol, sorbitol, etc.), etc., and one kind alone or two kinds The above can be used together. Examples of polycarboxylic acids include aliphatic dicarboxylic acids such as malonic acid, maleic acid, succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid and dodecanedioic acid; alicyclic rings such as 1,4-cyclohexanedicarboxylic acid. Group dicarboxylic acids; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, trimellitic acid, phthalic anhydride, trimellitic anhydride, etc. More than one species can be used together. Examples of the cyclic ester include propiolactone, β-methyl-δ-valerolactone, ε-caprolactone and the like, and one kind may be used alone or two or more kinds may be used in combination. Commercially available polyester polyols are specifically Kuraray Polyol P-510, Kuraray Polyol P-1010, Kuraray Polyol P-2010, Kuraray Polyol F-510, Kuraray Polyol F-1010, Kuraray Polyol F-2010, and Kuraray Polyol F. -3010 (above, manufactured by Kuraray Co., Ltd.), PLAXEL 205, PLAXEL 205H, PLAXEL L205AL, PLAXEL 205U, PLAXEL 208, PLAXEL 210, PLAXEL 303, PLAXEL 305, PLAXEL 308, PLAXEL 309, PLAXEL 312, PLAXEL 320, PLAXEL L320AL. , Praxel 410 (above, manufactured by Daicel Corporation) and the like.

Examples of the polycarbonate polyol include a reaction product of a polyhydric alcohol and phosgene; a ring-opening polymerization product of a cyclic carbonic acid ester (alkylene carbonate or the like). Examples of the polyhydric alcohol include those described above. Examples of the alkylene carbonate include ethylene carbonate, trimethylene carbonate, tetramethylene carbonate, hexamethylene carbonate and the like. Commercially available products of polycarbonate polyols include, specifically, Duranol T4691, Duranor T5650J, Duranor T5650E, Duranor G3450J (all manufactured by Asahi Kasei Co., Ltd.), Praxel CD205PL, Praxel CD210, Praxel CD220, Praxel CD220PL (or more, Co., Ltd.). Daicel), Kuraray Polyol C-590, Kuraray Polyol C-1090, and Kuraray Polyol C-2090 (all manufactured by Kuraray Co., Ltd.) and the like.

Examples of the acrylic polyol include homopolymers or copolymers of acrylic monomers having one or more hydroxyl groups in one molecule, or those obtained by copolymerizing these copolymers with other monomers. These may be used alone or in combination of two or more. Specific examples of commercially available acrylic polyols include ARUFON UH-2041 and ARUFON UHE-2012 (all manufactured by Toagosei Co., Ltd.).

Examples of the polyolefin polyol include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, and chlorinated products thereof. Specific examples of commercially available polyolefin polyols include Epol (made by Idemitsu Kosan Co., Ltd.) and NISSO-PB GI-1000 (made by Nippon Soda Co., Ltd.).

From the viewpoint of solvent resistance, the component (A) is preferably castor oil-based modified polyol, polyether polyol, polyester polyol, polycarbonate polyol, or acrylic polyol.

The physical properties of the component (A) are not particularly limited. The molecular weight of the component (A) is preferably about 300 to 30,000, more preferably about 600 to 20,000, from the viewpoint of excellent balance between solvent resistance and releasability. In addition, the "molecular weight" in this specification is a formula weight or a number average molecular weight, and when a molecular weight can be specified by the formula weight of a chemical formula, it says a formula weight. The number average molecular weight is a value in terms of polystyrene by gel permeation chromatography. (The same applies below).

From the viewpoint of solvent resistance, the hydroxyl value of component (A) (according to JIS K0070; hereinafter the same as hydroxyl value) is preferably about 50 to 500 mgKOH/g, more preferably about 100 to 400 mgKOH/g. ..

The content of the component (A) is not particularly limited, but from the viewpoint that the cured film has excellent solvent resistance, it is preferably about 20 to 80% by mass, and 30 to 70% by mass based on 100% by mass of the total solid content of the coating agent. % Is more preferable. The "total solid content" means the total solid content of the coating agent. The same applies below.

The component (B) is a component that imparts releasability, and is not particularly limited as long as it is a self-condensate of an aliphatic hydroxycarboxylic acid (b) having 12 to 24 carbon atoms (hereinafter referred to as the component (b)). When the component (B) is a self-condensation product of the component (b), the coating agent can form a transparent and smooth cured film, and has an excellent coating film appearance. Although the details are unknown, in the coating film containing the single compound of the component (b), the single compound has high crystallinity, so that the coating film becomes cloudy due to crystal precipitation, and unevenness is formed on the coating surface due to the insoluble component. On the other hand, in the coating film containing the self-condensate of the component (b), on the other hand, the self-condensate has low crystallinity, and therefore it is presumed that the above defects are not observed. As the component (B), one type can be used alone, or two or more types can be used in combination.

As the component (b), various known compounds can be used without particular limitation as long as they are aliphatic hydroxycarboxylic acids having 12 to 24 carbon atoms. Regarding the carbon number of the component (b), it is preferable that the number of carbon atoms is large from the viewpoint of light release of the cured film, but from the viewpoint of achieving both light release of the cured film and excellent appearance of the coating film, The carbon number is usually about 12 to 24, preferably about 14 to 22, more preferably about 16 to 20, and from the same point, the number of carbon is preferably about 18. If the component (b) is an aliphatic hydroxycarboxylic acid having 11 or less carbon atoms, the cured film has low peelability, and if it is an aliphatic hydroxycarboxylic acid having 25 or more carbon atoms, the appearance of the coating film is poor. The aliphatic hydroxycarboxylic acid in the present invention means an aliphatic monocarboxylic acid having one hydroxyl group in the molecule.

Specific examples of the component (b) include hydroxylauric acid such as 2-hydroxylauric acid and 3-hydroxylauric acid, hydroxymyristic acid such as 2-hydroxymyristic acid and 3-hydroxymyristic acid, and 2-hydroxypenta. Hydroxypentadecyl acid such as decyl acid, 3-hydroxypentadecyl acid, 2-hydroxypalmitic acid, hydroxypalmitic acid such as 3-hydroxypalmitic acid, 2-hydroxystearic acid, 3-hydroxystearic acid, 12-hydroxystearic acid Hydroxystearic acid such as 2-hydroxyarachidic acid, hydroxyarachidic acid such as 3-hydroxyarachidic acid, hydroxybehenic acid such as 2-hydroxybehenic acid and 3-hydroxybehenic acid, 2-hydroxylignoceric acid, Examples thereof include hydroxy lignoceric acid such as 3-hydroxylignoceric acid, ricinoleic acid, hydrogenated castor oil fatty acid (main component is 12-hydroxystearic acid), and castor oil fatty acid (main component is ricinoleic acid). Among them, 2-hydroxystearic acid, 3-hydroxystearic acid, 12-hydroxystearic acid, ricinoleic acid, hydrogenated castor oil fatty acid, castor oil fatty acid, and the like from the viewpoint of achieving both light release and excellent coating film appearance. An aliphatic hydroxycarboxylic acid having 18 carbon atoms is preferable, and 12-hydroxystearic acid and ricinoleic acid are more preferable because of easy availability. 12-Hydroxystearic acid is industrially obtained by hydrolyzing hydrogenated castor oil or by hydrogenating ricinoleic acid. Ricinoleic acid is obtained by saponification of castor oil. The 12-hydroxystearic acid obtained by the above hydrolysis contains a small amount of stearic acid or palmitic acid as impurities, but these may be contained in the coating agent of the present invention.

The component (B) can be obtained by self-condensing the component (b) by various known methods. Although the method is not particularly limited, for example, in an inert gas atmosphere, the component (b) is heated to a temperature of about 150 to 250° C., and water is removed from the system by azeotropic distillation in the presence of toluene and xylene. However, it can be obtained by dehydration condensation. Further, a catalyst such as a titanium compound, p-toluenesulfonic acid, sulfuric acid may be present. Examples of commercially available products of the component (B) include PHF-33, PCF-30 (above, manufactured by Ito Oil Co., Ltd.), K-PON306, K-PON402, K-PON404, K-PON406 (above, Ogura Gosei). Industrial Co., Ltd.), HSC-32, HSC-47, HSC-60D, HSC-95 (above, Toyokuni Oil Co., Ltd.), KF-3400, KF-4500, KF-4013, KF-4055E, KF. -40E (above, KF Trading Co., Ltd. product) etc. are mentioned.

The physical properties of the component (B) are not particularly limited. The hydroxyl value of component (B) (JIS K0070; hereinafter the same as the hydroxyl value) is preferably about 10 to 50 mgKOH/g from the viewpoint of light release, and about 20 to 40 mgKOH/g from the same point. More preferable.

The number average molecular weight of the component (B) is preferably about 500 to 3,000, more preferably about 1,000 to 2,000, from the viewpoint of achieving both light release of the cured film and excellent appearance of the coating film.

The component (B) is preferably a dimer to a trimer of the component (b), and more preferably a trimer to a octamer, from the viewpoint of achieving both light release of the cured film and excellent appearance of the coating film.

The component (B) has a structure having one hydroxyl group and one carboxyl group in one molecule, and the carboxyl group may be esterified. Since the component (B) has one hydroxyl group in one molecule, the coating agent of the present invention can form a cured film having a low peeling force. Below, an example of the structure of the component (B) is shown. The component (B) is different from the component (A).

The content of the component (B) is not particularly limited, but is preferably about 1 to 30% by mass based on 100% by mass of the total solid content of the coating agent, from the viewpoint of achieving both light release and solvent resistance of the cured film. Further, from the viewpoint of solvent resistance, about 1 to 20% by mass is more preferable.

As the component (C), various known compounds can be used without particular limitation as long as they are compounds having at least two isocyanate groups (-N=C=O) in the molecule. The component (C) reacts with the component (A) to form a crosslinked structure in the cured film, whereby a cured film excellent in solvent resistance and light peeling property can be obtained.

The component (C) is, for example, a linear aliphatic diisocyanate, a branched aliphatic diisocyanate, an alicyclic diisocyanate, an aromatic diisocyanate, a biuret body of these diisocyanates, an isocyanurate body, an allophanate body, an adduct body, and a biuret body, isocyanate. Examples thereof include a complex obtained by reacting two or more kinds selected from the group consisting of a nurate body, an allophanate body and an adduct body. These may be used alone or in combination of two or more.

A linear alkylene group etc. are illustrated as said linear aliphatic group. Linear alkylene groups of the general formula _:-( CH ₂₎ n - (n is represented by an integer of 1 or more). The linear alkylene group is specifically a methylene group, an ethylene group, a propylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, an n-heptylene group, an n-octylene group, an n-nonylene group, Examples thereof include n-decamethylene group.

Examples of the linear aliphatic diisocyanate include methylene diisocyanate, ethane diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate and the like. ..

Examples of the branched aliphatic group include a branched alkylene group and the like. The branched alkylene group is, for example, a group in which at least one hydrogen atom of a linear alkylene group is substituted with an alkyl group. Examples of the branched alkylene group include a diethylpentylene group, a trimethylbutylene group, a trimethylpentylene group, and a trimethylhexylene group.

Examples of the branched aliphatic diisocyanate include diethyl pentylene diisocyanate, trimethyl butylene diisocyanate, trimethyl pentylene diisocyanate, trimethyl hexamethylene diisocyanate, and the like.

Examples of the alicyclic group include a cycloalkylene group and the like. Cycloalkylene groups may have one or more hydrogen atoms replaced by a straight chain or branched alkyl group. The cycloalkylene group is, for example, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclodecylene group, a 3,5,5-trimethylcyclohexylene group, a tricyclodecylene group, an adamantylene group, a norbornylene group, a tricyclodecylene group. Group, adamantylene group, norbornylene group, bicyclodecylene group and the like.

The alicyclic diisocyanate is, for example, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, isophorone diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, cycloheptylene diisocyanate, cyclodecylene diisocyanate, tricyclodecylene diisocyanate, adamantane diisocyanate. , Norbornene diisocyanate, bicyclodecylylene diisocyanate and the like.

Examples of the aromatic group include a phenyl group (phenylene group), a tolyl group (tolylene group), a mesityl group (mesitylene group), and a naphthyl group (naphthylene group). In addition, one or more hydrogen atoms of these aromatic groups may be substituted with a linear or branched alkyl group.

The aromatic diisocyanate is, for example, dialkyldiphenylmethane diisocyanate such as 4,4′-diphenyldimethylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate such as 4,4′-diphenyltetramethylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 4, 4'-dibenzyl isocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, m-tetramethyl xylylene diisocyanate, 1,5-naphthylene diisocyanate and the like can be mentioned.

The biuret body of the diisocyanate,
The following structural formula:
[In the formula, n ^b is an integer of 1 or more, and R ^{bA to} R ^bE are each independently a linear aliphatic diisocyanate residue, a branched aliphatic diisocyanate residue, an alicyclic diisocyanate residue, and an aromatic diisocyanate. R ^{bα to} R ^bβ each independently represent an isocyanate group or
(N ^b1 is an integer of 0 or more, R ^{b1 to} R ^b5 are the same as R ^{bA to} R ^bE , and R ^b ′ to R ^b ″ are each independently an isocyanate group or R ^{bα to} R ^bβ itself. The groups of R ^{b4 to} R ^b5 and R ^b ″ may be different for each constitutional unit). The ^{groups of} R ^{bD to} R ^bE and R ^bβ may be different for each structural unit. ] The compound etc. represented by these are illustrated.

The biuret body of the above-mentioned diisocyanate is specifically, Duranate 24A-100, Duranate 22A-75P, Duranate 21S-75E (above, Asahi Kasei Corp.), Desmodur N3200A (hexamethylene diisocyanate biuret body) (above). , Sumitomo Bayer Urethane Co., Ltd., and the like.

The isocyanurate body of the diisocyanate,
The following structural formula:
Wherein, n ⁱ is an integer of 0 or more, R ^iA to R ^iE are each independently a straight-chain aliphatic diisocyanate residue, branched aliphatic diisocyanate residue, an alicyclic diisocyanate residue and an aromatic diisocyanate R ^{iα to} R ^iβ each independently represent an isocyanate group or
(N ⁱ¹ is an integer of 0 or more, R ^{i1 to} R ⁱ⁵ are the same as R ^{iA to} R ^iE , and R ⁱ ′ to R ⁱ ″ are each independently an isocyanate group or R ^{iα to} R ^iβ itself. The groups of R ⁱ⁵ and R ⁱ ″ may be different for each constitutional unit). The groups of R ^{iD to} R ^iE and R ^iβ may be different for each structural unit. ] The compound etc. represented by these are illustrated.

The above-mentioned isocyanurate body of the above-mentioned diisocyanate is, specifically, Duranate TPA-100, Duranate TKA-100, Duranate MFA-75B, Duranate MHG-80B (above Asahi Kasei Corp.), Coronate HXR, Coronate HX (above). , Isocyanurate of hexamethylene diisocyanate) (manufactured by Tosoh Corporation), Takenate D-127N (isocyanurate of hydrogenated xylylene diisocyanate) manufactured by Mitsui Chemicals, Inc., VESTANAT T1890/100 ( The isocyanurate body of isophorone diisocyanate) (above, Evonik Japan Co., Ltd. product) etc. are mentioned.

The allophanate form of the diisocyanate,
The following structural formula:
Wherein, ^{n a} is an integer of 0 or ^{more, R aA} is an alkyl group, an aryl group, a polyether group, a polyester group or polycarbonate ^group, R aB ^{to R aG} is independently a linear It is any one of an aliphatic diisocyanate residue, a branched aliphatic diisocyanate residue, an alicyclic diisocyanate residue and an aromatic diisocyanate residue, and R ^{aα to} R ^aγ are each independently an isocyanate group or
^{(N a1} is an integer of 0 or ^more, R a1 ^{to R a6} is the same as ^R aB ^{to R aG,} each ^{R a '~R a'} '' is independently, an isocyanate group, or ^{R aα ~R aγ} R ^{a1 to} R ^a4 and R ^a ′ to R ^a ′″ may be different groups for each constitutional unit). R ^{aB to} R ^aE and R ^{aα to} R ^aγ may have different groups for each structural unit. ] The compound etc. represented by these are illustrated.

Specific examples of the allophanate form of the diisocyanate include Coronate 2793 (manufactured by Tosoh Corporation) and Takenate D-178N (manufactured by Mitsui Chemicals, Inc.).

The adduct body of the diisocyanate,
The following structural formula:
[In the formula, n ^ad is an integer of 0 or more, and R ^{adA to} R ^adE are each independently a linear aliphatic diisocyanate residue, a branched aliphatic diisocyanate residue, an alicyclic diisocyanate residue, and an aromatic diisocyanate. R ^{ad1 to} R ^ad2 each independently represent a residue.
(In the formula, n ^{ad ′} is an integer of 0 or more, R ^{ad ′ to} R ^{ad ″} are the same as R ^{adA to} R ^adE , and R ^{ad ″′} is a group of R ^{ad1 to} R ^ad2 itself. And R ^{ad' to} R ^ad''' may have different groups for each constitutional unit.)
And R ^{adD to} R ^adE and R ^ad2 may have different groups for each structural unit. ]
An adduct of trimethylolpropane and diisocyanate,
The following structural formula
[ ^Wherein , n ^ad1 is an integer of 0 or more, and R ^{adα to} R ^{ad ε} are each independently a linear aliphatic diisocyanate residue, a branched aliphatic diisocyanate residue, an alicyclic diisocyanate residue and an aromatic diisocyanate. R ^{adA to} R ^adB independently of each other.
(In the formula, n ^{ad1 ′} is an integer of 0 or more, R ^{adδ ′ to} R ^{ad ε ′} are the same as R ^{ad α to} R ^{ad ε} , and R ^{adB ′} is the group of R ^{adA to} R ^adB itself, and R ^{The groups of adδ′ to} R ^adε′ and R ^adB′ may be different for each structural unit.)
R ^{adδ to} R ^{ad ε} may have different groups for each structural unit. ]
Examples thereof include adducts of glycerin and diisocyanate.

The adduct body of the diisocyanate specifically includes Duranate P301-75E (above, manufactured by Asahi Kasei Co., Ltd.), Takenate D-110N, Takenate D-160N (above manufactured by Mitsui Chemicals, Inc.), Coronate L, Coronate HL (all manufactured by Tosoh Corporation) and the like can be mentioned.

In each of the above formulas, the term "linear aliphatic diisocyanate residue, branched aliphatic diisocyanate residue, alicyclic diisocyanate residue and aromatic diisocyanate residue" means the linear aliphatic diisocyanate and the branched fat. Of the group diisocyanates, the alicyclic diisocyanates, and the aromatic diisocyanates, it means the remaining groups excluding the isocyanate groups.

From the viewpoint of solvent resistance, the component (C) is preferably a polyisocyanate having at least 3 isocyanate groups in the molecule. As the polyisocyanate having at least three isocyanate groups in the molecule, the biuret body, the isocyanurate body, the allophanate body, and the adduct body are preferable.

The isocyanate group content (NCO%) of the component (C) is not particularly limited, but is preferably about 10 to 30% from the viewpoint of solvent resistance.

The molar ratio (NCO/OH) of the isocyanate group contained in the component (C) to the hydroxyl group contained in the component (A) is not particularly limited, but is about 0.3 to 3 from the viewpoint of curability and light peeling. Is preferable, and about 0.5 to 2.5 is more preferable. Moreover, the solid content mass ratio ((C)/(A)) of the component (C) and the component (A) is not particularly limited, but from the same point, it is preferably about 0.1 to 3, and 0.3 About 2.5 is more preferable.

The content of the component (C) is not particularly limited, but from the viewpoint of curability and light release, it is preferably about 10 to 80% by mass with respect to 100% by mass of the total solid content of the coating agent, and 20 to 70% by mass. The degree is more preferable.

The coating agent of the present invention may further contain a curing catalyst (D) (hereinafter referred to as component (D)). As the component (D), various known curing catalysts can be used. Specifically, tertiary amine compounds such as triethylamine, triethylenediamine, 1,8-diazabicyclo(5,4,0)-undecene-7(DBU), dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, Dibutyltin dimaleate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, dioctyltin dilaurate, dioctyltin diversate, tributyl. Tin compounds such as tin chloride, tributyltin trichloroacetate, tin 2-ethylhexanoate, titanium tetraacetylacetonate, titanium diisopropoxybis(acetylacetonate), titanium diisopropoxybis(ethylacetoacetate), titanium di 2-ethylhexoxybis(2-ethyl-3-hydroxyhexoxide), titanium-based compounds such as tetrabutyl titanate, iron 2-ethylhexanoate, iron-based compounds such as iron acetylacetonate, zinc naphthenate, Examples thereof include zinc compounds such as zinc 2-ethylhexanoate, zirconium compounds such as zirconium tetraacetylacetonate, zirconium tributoxymonoacetylacetonate and zirconium naphthenate. These may be used alone or in combination of two or more.

From the viewpoint of reactivity, the component (D) is an organic tin catalyst such as dibutyltin dilaurate or dioctyltin dilaurate, an organic titanium catalyst such as titanium ethylacetoacetate, an organic zirconium catalyst such as zirconium tetraacetylacetonate, or an iron acetylacetonate. Organic iron catalysts and the like are preferable.

The content of the component (D) is not particularly limited, but from the viewpoint of curability and pot life, it is preferably about 0.1 to 5 mass% with respect to 100 mass% of the total solid content of the coating agent. From the same point, the content of the component (D) is preferably about 0.2 to 4 parts by mass based on 100 parts by mass of the total of the components (A) and (C).

The coating agent of the present invention may further contain an organic solvent (E) (hereinafter referred to as component (E)). Specific examples include methyl ethyl ketone, methyl isobutyl ketone, acetone, ethyl acetate, butyl acetate, toluene, xylene and the like, and one kind can be used alone, or two or more kinds can be used in combination. Among these, at least one selected from the group consisting of methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate and toluene is preferable from the viewpoint of solubility.

The content of the component (E) is not particularly limited, but from the viewpoint of pot life, it is usually preferable that the coating agent of the present invention has a solid content concentration of about 5 to 40% by mass. Within such a numerical range, the appearance of the cured film, the curability of the coating agent, and the adhesion of the cured film to the plastic film (particularly polyethylene terephthalate film) are well balanced.

The method for producing the coating agent of the present invention is not particularly limited, and examples thereof include a method of mixing the above components. The order of mixing the components is not particularly limited, and any component may be mixed. The mixing method is also not particularly limited, and various known methods such as stirring can be used.

In the coating agent of the present invention, in addition to the above components, various known additives, such as binders, defoamers, preservatives, rust preventives, and curing agents, may be added as necessary as long as the effects of the present invention are not impaired. , A pH adjusting agent, an antioxidant, a pigment, a dye, a lubricant, a leveling agent, an antiblocking agent, and a conductive agent can be added. The binder is not particularly limited, but examples thereof include phenol resin, epoxy resin, urea resin, urethane resin, and alkyd resin. Examples of the curing agent include an isocyanate curing agent, an epoxy curing agent, an aziridine curing agent, a carbodiimide curing agent, and an oxazoline curing agent.

The release film of the present invention is an article having a release layer composed of the coating agent of the present invention on at least one side, and the coating agent of the present invention is applied to various known base films and cured by heating or drying. It is obtained by

Examples of the base film include polycarbonate, polymethylmethacrylate, polystyrene, polyethylene terephthalate (PET), polyimide, polyolefin, nylon, epoxy resin, melamine resin, triacetyl cellulose resin, ABS resin, AS resin, norbornene resin, and the like. An example is a film made of plastic. The substrate film may be surface-treated (corona discharge, etc.). Among these, polyethylene terephthalate is preferable in terms of performance such as transparency, dimensional stability, mechanical properties, and chemical resistance. These plastic films may be provided with a layer of a coating agent other than the thermosetting release coating agent of the present invention on one side or both sides thereof.

The release layer (cured film) is formed by coating the thermosetting release coating agent of the present invention on various substrates so that the thickness after curing is about 0.01 to 10 μm, preferably about 0.1 to 5 μm. It is applied to, heated and dried.

The coating method is not particularly limited, and various known means may be used. Specific examples include roll coaters, reverse roll coaters, gravure coaters, knife coaters, bar coaters, and the like.

The heating and drying conditions are not particularly limited. The coating agent of the present invention is usually cured at about 90 to 130° C. and about 30 seconds to 2 minutes, but it is considered that general coating film forming conditions are usually about 150 to 190° C. and about 1 to 5 minutes. Then, it can be said that the coating agent of the present invention cures at a relatively low temperature. Therefore, the coating agent is suitable for a plastic film that is easily deformed by heat, particularly a polyethylene terephthalate film.

Examples of applications of the release film of the present invention include release films for manufacturing processes such as ceramic green sheets, synthetic leather, decorative plates, carbon fiber prepregs, and printed circuit boards, release films for transfer printing-related products, polarizing plates and retarders. Examples include release films for protecting adhesive layers such as plates.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In each example, parts and% are based on mass unless otherwise specified.

<Synthesis of acrylic polyol>
Production example 1
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen introducing tube, 80.0 parts by mass of methyl methacrylate, 3.0 parts by mass of n-butyl acrylate, and 2-hydroxyethyl acrylate. 17.0 parts by mass and 185.7 parts by mass of methyl ethyl ketone were charged, and the reaction system was set at 80°C. Next, 0.5 parts by mass of azobisisobutyronitrile was charged and the temperature was kept at about 80° C. for 5 hours. Next, 1.0 part by mass of azobisisobutyronitrile was charged, and the reaction system was kept at the same temperature for about 4 hours. Then, the reaction system was cooled to room temperature to obtain an acrylic polyol (solid content 35%, hydroxyl value 80 mgKOH/g, number average molecular weight 20000).

<Preparation of thermosetting release coating agent>
Example 1
100 parts by mass of URIC F-97 (castor oil-modified polyol manufactured by Ito Oil Co., Ltd., solid content 100%) as the component (A), and PHF-33 (self-condensation product of 12-hydroxystearic acid as the component (B) Ito oil ( Co., Ltd. (solid content 100%) 10 parts by mass, (C) component Coronate HX (isocyanurate body of hexamethylene diisocyanate Tosoh Co., Ltd. solids 100%) 120 parts by mass, as a catalyst Neostan U-830 (dioctyltin) 1 part by weight of Gibacertate Nitto Kasei Co., Ltd. (solid content 100%) was mixed, and this was diluted with methyl ethyl ketone to prepare a solid content concentration of 15%. (Also referred to as coating agent).

Examples 2-10, Comparative Examples 1-5
The procedure of Example 1 was repeated except that the composition was changed to that shown in Table 1.

<Preparation of release film>
The release agent was coated with the coating agent of Example 1 onto a polyethylene terephthalate film (film thickness 50 μm, Toray Industries, Inc. “Lumirror T60”) so that a cured film was 1 μm, and dried at 120° C. for 1 minute. Obtained. Release films were similarly obtained for the coating agents of the other Examples and Comparative Examples.

(Appearance of coating film)
In the above production of the release film according to Example 1, the appearance of the cured film was observed, and the appearance of the coating film was evaluated according to the following criteria. The release films according to other examples and comparative examples were also evaluated in the same manner.
◯: A transparent and smooth cured film was obtained.
X: The cured film became cloudy, or
Unevenness was left in the coating agent, and unevenness was observed in the cured film.

(Solvent resistance)
The cured film of the release film according to Example 1 was rubbed with a cotton swab dipped in methyl ethyl ketone, and the number of reciprocations until the substrate was exposed was measured to evaluate the solvent resistance of the cured film. Solvent resistance was evaluated in the same manner for release films according to other examples and comparative examples.
A: The surface of the base film (polyethylene terephthalate film) is not exposed even after rubbing 30 times or more.
◯: The surface of the base film is exposed when rubbed 11 to 29 times.
Δ: The surface of the base film is exposed when rubbed 2 to 10 times.
X: The surface of the base film is exposed only by rubbing once.

(Peeling force)
A polyester pressure-sensitive adhesive tape (31B tape manufactured by Nitto Denko KK: 25 mm width) was attached to the cured film of the release film according to Example 1 while being pressed with a 2 kg roller. Then, this tape was peeled off at an angle of 180° of 0.3 m/min. The force (N/25 mm) required for pulling and peeling was measured. The peeling force was similarly measured for the peeling films according to other examples and comparative examples.

The blending amount in Table 1 is a value of parts by mass in terms of solid content. The abbreviations and annotations in Table 1 are as follows.
(1) Since the appearance of the coating film was uneven or whitened, the solvent resistance and the peeling force were not evaluated.

(Compound abbreviations and details)
URIC F-97: Castor oil type modified polyol (solid content 100%, hydroxyl value 332 mgKOH/g) PTMG650 manufactured by Ito Oil Co., Ltd.: polytetramethylene glycol (solid content 100%, hydroxyl value 170 mgKOH/g) Mitsubishi Chemical (stock) ) P-1010: Polyester polyol (solid content 100%, hydroxyl value 112 mgKOH/g) Duranor G3450J manufactured by Kuraray Co., Ltd.: Polycarbonate polyol (solid content 100%, hydroxyl value 140 mgKOH/g) PHF-33 manufactured by Asahi Kasei Corporation 12-Hydroxystearic acid self-condensate (solid content 100%, number average molecular weight 1800) Ito Oil Co., Ltd. 12-hydroxystearic acid: Ito Oil Co., Ltd. Coronate HX: hexamethylene diisocyanate isocyanurate (solid 100%, NCO% 21%, three isocyanate groups in the molecule) Tosoh Corp. Takenate D-110N: trimethylolpropane adduct of xylylene diisocyanate (solid content 100%, NCO% 15.3%, Three isocyanate groups in the molecule) Mitsui Chemicals, Inc. Neostan U-830: Dioctyltin diversate (solid content 100%) Nitto Kasei Co., Ltd. Piroyl 1010S: Long chain alkyl pendant polymer (solid content 100) %) Lion Specialty Chemicals Co., Ltd.

Claims (9)

A thermosetting release coating agent containing a polyol (A), a self-condensate (B) of an aliphatic hydroxycarboxylic acid (b) having 12 to 24 carbon atoms, and a polyisocyanate (C). The thermosetting release coating agent according to claim 1, wherein the hydroxyl value of the component (A) is 50 to 500 mgKOH/g. The thermosetting release coating agent according to claim 1 or 2, wherein the component (B) is a self-condensation product of an aliphatic hydroxycarboxylic acid having 18 carbon atoms. The thermosetting release coating according to any one of claims 1 to 3, wherein the content of the component (B) is 1 to 30% by mass based on 100% by mass of the total solid content of the thermosetting release coating agent. Agent. The thermosetting release coating agent according to any one of claims 1 to 4, wherein the component (C) is a polyisocyanate having at least 3 isocyanate groups in the molecule. The heat according to claim 1, wherein the molar ratio (NCO/OH) of the isocyanate group contained in the component (C) and the hydroxyl group contained in the component (A) is 0.3 to 3.0. Curable release coating agent. Furthermore, the thermosetting release coating agent in any one of Claims 1-6 containing a curing catalyst (D). A release film comprising a cured film comprising the thermosetting release coating agent according to claim 1 and a plastic film. The release film according to claim 8, wherein the plastic film is a polyethylene terephthalate film.