TW201922975A - Thermosetting release coating agent and release film capable of forming a cured film excellent in appearance of a coating film and excellent in peeling property and solvent resistance - Google Patents

Abstract

The present invention provides a novel thermosetting release coating agent characterized in that the thermosetting release coating agent is capable of forming a cured film excellent in appearance of a coating film and excellent in peeling property and solvent resistance. The present invention provides a thermosetting release coating agent characterized by comprising: a melamine resin (A), a self-condensate (B) containing an aliphatic hydroxy acid (b) having a carbon number of 12 to 24, and an acid catalyst (C). Specifically, the coating agent is suitable for a release agent to release the polyester film.

Description

Thermosetting release coating agent, and release film

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

The biaxially stretched polyester film represented by a polyethylene terephthalate film has excellent transparency, dimensional stability, mechanical properties, chemical resistance and the like, and is utilized in various industrial fields. In recent years, it has been used in various optical films, and has been used for various applications such as a base sheet of an LCD unit, a light-diffusing sheet, a reflector, a base film for a touch screen, or a base film for preventing reflection. In addition, it is also widely used as a base film for a release film, and is also widely used for an adhesive material, an adhesive tape, a protective film for a touch screen, and an electronic material for manufacturing a ceramic green sheet.

The conventional release film is mainly formed of a release layer formed of a resin coating film of a silicone resin release agent having releasability on the surface of the polyester film. However, it has been pointed out that in the case where the resin coating film is formed using a ruthenium-based release agent, the low molecular weight oxime compound derived from the oxime-based release agent is transferred from the resin coating film to the adhesive of the adhesive sheet. On the surface of the layer, there is a concern that the adhesion of the adhesive layer is lowered, or that the electronic component to which the sheet is adhered is problematic. In addition, the peeling film for the manufacturing steps of the ceramic green sheet or the printed circuit board for the capacitor, the sealing step of various electronic parts, etc., is also pointed out to be affected by the above-mentioned oxygen compound shifting. Go to the surface of the electronic component and the fault occurs.

In order to suppress the contamination by the above-described oxygen-containing compound, a non-oxygen-based release agent has been proposed (see Patent Documents 1 and 2). Patent Documents 1 and 2 disclose a non-oxygen-based release agent containing a long-chain alkyl side chain type polymer formed by reacting a polyvinyl alcohol or an ethylene-vinyl alcohol copolymer with a long-chain alkyl isocyanate.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2000-119608

[Patent Document 2] Japanese Patent Laid-Open No. Hei 5-295332

However, the release agent disclosed in Patent Documents 1 and 2 has excellent peelability from the coating film formed therefrom, but the coating film is not crosslinked, and the solvent resistance is low. Further, since the release agent has low solubility in various solvents, the coating film formed of the release agent tends to have flaws in appearance such as white turbidity or unevenness, and has a problem that the appearance of the coating film is not good.

An object of the present invention is to provide a novel thermosetting release coating agent which can form a cured film which is excellent in appearance of a coating film and excellent in peeling property and solvent resistance.

The inventors, after intensive research, found that by specifying the trimerization The composition of the cyanamide resin and the specified self-condensation product of the aliphatic hydroxy acid and the acid catalyst can solve the above problems, and the present invention has been completed. That is, the present invention relates to the following thermosetting release coating agent and release film.

A thermosetting release coating agent comprising: a melamine resin (A), an aliphatic hydroxy acid having a carbon number of 12 to 24 (b), a self condensate (B), and an acid catalyst (C) .

2. The thermosetting release coating agent according to the above item 1, wherein the component (A) contains a constituent unit derived from methylated melamine and/or butylated melamine.

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

4. The thermosetting release coating agent according to any one of the preceding claims, wherein the content of the component (B) is from 1 to 50% by weight based on 100% by weight of the total solid content of the release coating agent. weight%.

The thermosetting release coating agent according to any one of the items 1 to 4, wherein the component (C) is an organic sulfonic acid and/or an organic phosphoric acid.

The thermosetting release coating agent according to any one of the above items 1 to 5, wherein the content of the component (C) is 1 to 10% by weight based on 100% by weight of the total solid content of the release coating agent. weight%.

The thermosetting release coating agent according to any one of the items 1 to 6, further comprising a polyol (D).

8. The thermosetting release coating agent according to the above item 7, wherein the weight ratio of the component (A) to the component (D) is 90/10 to 30/70.

A release film comprising: any one of the preceding items 1 to 8 A cured film and a plastic film formed by the thermosetting release coating agent described.

10. The release film according to the above item 9, wherein the plastic film is a polyethylene terephthalate film.

The thermosetting release coating agent of the present invention can be dried by heating in a short period of time to form a cured film (stable hardenability) which is light in peeling force and excellent in solvent resistance. Further, the cured film formed of 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 of a polyester film as a base film.

The thermosetting release coating agent (hereinafter referred to as a coating agent) of the present invention contains a melamine resin (A) (hereinafter referred to as component (A)) and an aliphatic hydroxy acid having a carbon number of 12 to 24 (b). The composition of the self-condensation product (B) (hereinafter referred to as (B) component) and the acid catalyst (C) (hereinafter referred to as component (C)).

The component (A) is not particularly limited as long as it is a melamine resin, and various conventionally used ones can be used. For example, a resin containing a constituent unit derived from a compound represented by the following general formula (1) can be exemplified. The average degree of polymerization of the component (A) is not particularly limited, but is usually about 1.1 to 10.

(In the formula (1), R ¹ to R ⁶ may be the same or different, and each represents a hydrogen atom, a hydroxymethyl group (-CH ₂ OH), a methoxymethyl group (-CH ₂ OCH ₃ ), or an ethoxy group. Base (-CH ₂ OCH ₂ CH ₃ ), n-butoxymethyl (-CH ₂ OCH ₂ CH ₂ CH ₂ CH ₃ ) and isobutoxymethyl (-CH ₂ OCH(CH ₃ )CH ₂ CH ₃ ) Selected in the middle.)

The component (A) is a resin containing a constituent unit derived from methylated melamine and/or butylated melamine, from the viewpoint of the excellent quick-curing property of the coating agent and the mutual solubility balance with the component (B) described later. good. Refers to: methylated melamine, wherein at least one of the substituents R ¹ to R ⁶ of the above general formula (1) is methoxymethyl (-CH ₂ OCH ₃ ); butylated melamine is the substitution At least one of the groups is n-butoxymethyl (-CH ₂ OCH ₂ CH ₂ CH ₂ CH ₃ ) or isobutoxymethyl (-CH ₂ OCH(CH ₃ )CH ₂ CH ₃ ).

The component (A) is a resin containing a constituent unit derived from the monoether methylated melamine in which all of R ¹ to R ⁶ are methoxymethyl groups (hereinafter, referred to as a full ether type) from the viewpoint of excellent rapid curability. A methylated melamine resin is preferred; and any one derived from the R ¹ to R ^{6 is} n-butoxymethyl or isobutoxymethyl, depending on the mutual solubility with the component (B) described later. The resin of the constituent unit of the perether type butylated melamine (hereinafter referred to as a full ether type butylated melamine resin) is preferred. Further, according to the excellent speed hardenability and the mutual solubility balance with the component (B) described later, at least one of the R ¹ to R ^{6 is} contained in the methoxymethyl group, and the others are n- A resin of a constituent unit of a full ether type methylated butylated melamine of any one of a butoxymethyl group or an isobutoxymethyl group (hereinafter referred to as a full ether type methylated butylated melamine resin) is preferred.

The component (A) may be a commercially available product, and may be, for example, CYMEL 300, CYMEL 301, CYMEL 303LF, CYMEL 350, CYMEL 370N, CYMEL 771, CYMEL 325, CYMEL 327, CYMEL 703, CYMEL 712, CYMEL 701, CYMEL 266 , CYMEL 267, CYMEL 285, CYMEL 232, CYMEL 235, CYMEL 236, CYMEL 238, CYMEL 272, CYMEL 212, CYMEL 253, CYMEL 254, CYMEL 202, CYMEL 207, MYCOAT 506 (above, manufactured by Allnex Japan Inc.), NIKALAC MW-30M, NIKALAC MW-30, NIKALAC MW-30HM, NIKALAC MW- 390, NIKALAC MW-100LM, NIKALAC MX-750LM, NIKALAC MW-22, NIKALAC MS-21, NIKALAC MS-11, NIKALAC MW-24X, NIKALAC MS-001, NIKALAC MX-002, NIKALAC MX-730, NIKALAC MX- 750, NIKALAC MX-708, NIKALAC MX-706, NIKALAC MX-042, NIKALAC MX-035, NIKALAC MX-45, NIKALAC MX-43, NIKALAC MX-417, NIKALAC MX-410 (above, Sanhe CHEMICAL Co., Ltd.) System), U-VAN 20SB, U-VAN 20SE60, U-VAN 21R, U-VAN 22R, U-VAN 122, U-VAN 125, U-VAN 220, U-VAN 225, U-VAN 228, U- VAN 2020 (above, Mitsui Chemicals Co., Ltd.), AMIDIR J-820-60, AMIDIR L-109-65, AMIDIR L-117-60, AMIDIR L-127-60, AMIDIR 13-548, AMIDIR G-821 -60, AMIDIR L-110-60, AMIDIR L-125-60, AMIDIR L-166-60B (above, DIC Corporation), etc., may be used alone or in combination of two or more. The content of the component (A) is not particularly limited. However, from the viewpoint of obtaining the solvent resistance of the cured film, it is preferably about 25 to 98% by weight based on 100% by weight of the total solid content of the coating agent, and 30 to 95% by weight. About weight% is better. In addition, "all solids" means the total composition of the coating agent after removing the component (E) described later. The following is the same.

The component (B) is a component which imparts releasability, and is a self-condensation product of the aliphatic hydroxy acid (b) having a carbon number of 12 to 24 (hereinafter referred to as component (b)), and is not particularly limited. Since the component (B) is a self-condensate of the component (b), the coating agent can form a transparent and smooth cured film, and the coating film is excellent in appearance. Although the details are not clear, since the single compound of the component (b) has high crystallinity, it is presumed that the coating film containing the single compound may be cloudy due to crystallization, or may be formed on the surface of the coating film. The unevenness caused by the insoluble components in the medium. On the other hand, since the crystallinity of the self-condensation product of the component (b) is low, the coating film containing the self-condensation product is estimated, and the above problem does not occur.

The component (b) is not particularly limited as long as it is an aliphatic hydroxy acid having 12 to 24 carbon atoms, and various conventionally used ones can be used. The carbon number of the component (b) is preferably a number of carbon atoms from the viewpoint of lightly peeling off the cured film, and the component (b) is based on the viewpoint that the cured film can be lightly peeled off and the appearance of the film is excellent. The carbon number is usually around 12~24, about 14~22 is better, and about 16~20 is better. According to the same point of view, around 18 is especially good. When the component (b) is an aliphatic hydroxy acid having a carbon number of 11 or less, the peeling property of the cured film is lowered, and when it is an aliphatic hydroxy acid having a carbon number of 25 or more, the appearance of the coating film is deteriorated. Further, the aliphatic hydroxy acid in the present invention means an aliphatic monocarboxylic acid having a hydroxyl group in its molecule.

Specific examples of the component (b) include, for example, 2-hydroxylauric acid, hydroxylauric acid such as 3-hydroxylauric acid, 2-hydroxy myristic acid, hydroxy myristic acid such as 3-hydroxy myristic acid, and 2 Hydroxypentadecanoic acid such as hydroxydodecanoic acid, 3-hydroxypentadecanoic acid, hydroxypalmitic acid such as 2-hydroxypalmitic acid or 3-hydroxypalmitic acid, 2-hydroxystearic acid, 3-hydroxystearic acid, Hydroxy arachidic acid such as hydroxystearic acid such as 12-hydroxystearic acid, 2-hydroxyarachiic acid or 3-hydroxyarachidic acid, hydroxyarachiic acid such as 2-hydroxy aramic acid, 3-hydroxy carboxylic acid, etc., 2-hydroxyl Hydroxytetradecanoic acid such as tetrazoic acid, 3-hydroxytetracosic acid, ricinoleic acid, hardened castor oil fatty acid (main component 12-hydroxystearic acid), and castor oil fatty acid (main component system castor oil) Acid) and so on. Among them, according to the viewpoint of light peeling and excellent appearance of the coating film, 2-hydroxystearic acid, 3-hydroxystearic acid, 12-hydroxystearic acid, ricinoleic acid, hardened castor oil fatty acid, and hydrazine are used. Ethanol fatty acid and other aliphatic 18-hydroxy hydroxy acid Preferably, 12-hydroxystearic acid or ricinoleic acid is more preferred from the viewpoint of easy availability. 12-hydroxystearic acid, which is industrially obtainable by hydrolyzing hardened castor oil or hydrogenated ricinoleic acid. Ricinoleic acid, which can be obtained from saponified castor oil. Further, although 12-hydroxystearic acid obtained by the above hydrolysis contains a small amount of impurities such as stearic acid or palmitic acid, these may be contained in the coating agent of the present invention.

The component (B) can be obtained by subjecting the component (b) to self-condensation by various conventional methods. The method is not particularly limited, and for example, the component (b) is heated to about 150 to 250 ° C in an inert gas atmosphere, and the water is removed to the system by azeotropy in the presence of toluene and xylene. In addition, one side is subjected to dehydration condensation. Further, a catalyst such as a titanium compound, p-toluenesulfonic acid or sulfuric acid may be added. For the commercially available product of the component (B), for example, PHF-33, PCF-30 (above, manufactured by Ito Oil Co., Ltd.), K-PON306, K-PON402, K-PON404, K-PON406 (above, Ogura) Synthetic Industry Co., Ltd.), HSC-32, HSC-47, HSC-60D, HSC-95 (above, manufactured by Fengguo Oil Co., Ltd.), KF-3400, KF-4500, KF-4013, KF-4055E KF-40E (above, KF Trading Co., Ltd.).

The hydroxyl value of the component (B) (JIS K0070. Hereinafter, the hydroxyl value is also the same) is not particularly limited, but it is preferably 10 to 50 mgKOH/g from the viewpoint of light peeling, and 20 to 20% from the same viewpoint. 40 mg KOH/g is more preferred. Further, the number average molecular weight of the component (B) (the polystyrene-converted value according to the gel permeation chromatography, hereinafter, the number average molecular weight is also the same) is not particularly limited, but may be lightly peeled off depending on the cured film. The viewpoint of the appearance of a good coating film and the appearance of a good coating film is preferably about 500 to 3,000, and more preferably about 1,000 to 2,000. Further, the component (B) is preferably a 2 to 10 polymer of the component (b), and a 4 to 8 polymer is more preferable from the viewpoint of allowing the cured film to be lightly peeled off and the appearance of the excellent film to be uniform.

The component (B) is a structure in which one molecule contains a hydroxyl group and a carboxyl group, and the carboxyl group is also esterifiable. Since the component (B) contains a hydroxyl group in one molecule, the coating agent of the present invention can form a cured film having a light peeling force. The following formula shows an example of the structure of the component (B).

The content of the component (B) is not particularly limited, and it is about 1 to 50% by weight based on 100% by weight of the total solid content of the coating agent, from the viewpoint of allowing the light-peeling and the solvent resistance of the cured film to stand side by side. Good, about 2~30% by weight is better.

The component (C) is not particularly limited as long as it is an acid catalyst, and various conventionally used ones can be used. Specifically, for example, inorganic acids or organic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and the like can be exemplified. The organic acid may, for example, be a carboxylic acid such as oxalic acid, acetic acid or formic acid; methanesulfonic acid, trifluoromethanesulfonic acid, 3-methyl-1,3-butadiene-2-sulfonic acid, camphorsulfonic acid, Hexanesulfonic acid, octanesulfonic acid, decanesulfonic acid, decanesulfonic acid, hexadecanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, cumenesulfonic acid, dodecylbenzenesulfonic acid, naphthalene Organic sulfonic acid such as sulfonic acid or mercapto naphthalenesulfonic acid; methyl phosphate, ethyl phosphate, propyl phosphate, isopropyl phosphate, butyl phosphate, butoxyethyl phosphate, octyl phosphate Salt, 2-ethylhexyl phosphate, decyl phosphate, lauryl phosphate, octadecyl phosphate, oleyl phosphate, tetradecyl phosphate, phenyl phosphate, decyl phenyl phosphate Salt, cyclohexane phosphate, phenoxyethyl phosphate, alkoxy polyethylene glycol phosphate, bisphenol A phosphate, dimethyl phosphate, diethyl phosphate, dipropyl phosphate Salt, diisopropyl phosphate Esters, dibutyl phosphate, dioctyl phosphate, di(2-ethylhexyl) phosphate, dilauryl phosphate, di(octadecyl) phosphate, diphenyl phosphate, phosphoric acid An organic acid phosphate such as a dimercaptophenyl ester salt; a thermal acid generator such as a phosphonium salt, a benzothiazolium salt, an ammonium salt or a phosphonium salt; and the like. These may be used alone or in combination of two or more.

The component (C) is preferably an organic acid based on the viewpoint of good mutual solubility with the components (A) and (B). Further, from the viewpoint of the quick-curing property, the above-mentioned organic sulfonic acid and/or the above-mentioned organic phosphoric acid are preferred, and from the same viewpoint, an organic sulfonic acid is particularly preferable.

The content of the component (C) is not particularly limited, but it is about 1 to 10% by weight based on 100% by weight of the total solid content of the coating agent, depending on the viewpoint of the quick-setting property and the management stability of the coating agent. It is better, about 2~8 wt% is better. Further, from the same viewpoint, it is preferably about 2 to 25 parts by weight based on 100 parts by weight of the total of the components (A) and (B), and more preferably about 3 to 10 parts by weight.

The coating agent of the present invention may further contain a polyol (D) (hereinafter referred to as component (D)) which can form a crosslinked structure with the component (A). The component (D) is not particularly limited as long as it contains two or more hydroxyl groups per molecule, and various conventionally used ones can be used. Specifically, for example, ethylene glycol, 2-methyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 2-methyl- 1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,9-nonanediol, 1,10-decanediol, ethylbutylpropanediol, ethylbutylpentanediol An aliphatic diol; an alicyclic diol such as 1,4-cycloethane dimethanol; 1,1,1-trimethylolpropane, pentaerythritol, ditrimethylolpropane, Dipentaerythritol, dimer diol, hydrogenated dimer diol, terpolymer triol, hydrogenated terpolymer triol, castor oil, castor oil denatured polyol, and bisphenol compound An ethylene oxide addenda of a derivative thereof or the like. In addition, for example, polyether polyol, polyester polyol, polycarbonate polyol, A polymer polyol such as a propylene polyol or a polyene polyol. These may be used alone or in combination of two or more. Further, the component (D) is different from the component (B) described above.

The molecular weight of the component (D) is usually about 60 to 3,000 from the viewpoint of rapid hardenability, and preferably about 80 to 2,000, more preferably 100 to 1,500. Further, the molecular weight of the component (D), the amount of the formula or the number average molecular weight, if the molecular weight can be determined by the formula, is called the formula. The number average molecular weight, as described above, is a polystyrene-converted value according to gel permeation chromatography. The hydroxyl value of the component (D) is preferably from about 50 to 2,000 mgKOH/g, more preferably from about 100 to 1,500 mgKOH/g, from the viewpoint of rapid hardenability.

In the coating agent of the present invention, the content ratio of the component (A) and the component (D) is not particularly limited, but the weight ratio [(A)/ is based on the viewpoint that the quick-curing property and the solvent resistance of the cured film can be set in parallel. (D)] It is better to be around 90/10~30/70, and about 80/20~40/60 is better. Further, the content of the component (D) is not particularly limited, but it is 10 to 60% by weight based on 100% by weight of the total solid content of the coating agent, depending on the viewpoint of the quick-hardenability and the solvent resistance of the cured film. % is better.

The coating agent of the present invention may further contain an organic solvent (E) (hereinafter referred to as component (E)). Specifically, for example, methyl ethyl ketone, methyl isobutyl ketone, acetone, ethyl acetate, butyl acetate, toluene, xylene, isopropanol, ethanol, butanol or the like can be exemplified, and one type or more can be used. Among these, it is preferred that at least one selected from the group consisting of methyl ethyl ketone, methyl isobutyl ketone, isopropyl alcohol, ethyl acetate, and toluene is used in view of solubility.

The content of the component (E) is not particularly limited, but it is usually preferably such that the solid content of the coating agent of the present invention is in the range of about 1 to 50% by weight. This range of values gives the appearance of the film of the cured film, the hardenability of the coating agent, and the plastic film (especially polyethylene terephthalate). The film of the film) has a good balance of compactness.

The method for producing the coating agent of the present invention is not particularly limited, and for example, a method of mixing the above components can be exemplified. The order of mixing the components is not particularly limited, and mixing can be started from any of the components. Further, the mixing method is not particularly limited, and various conventional methods such as stirring can be used.

The coating agent of the present invention may be blended with various conventional additives as necessary, and examples thereof include a binder, an antifoaming agent, a preservative, a rust inhibitor, a hardener, a pH adjuster, an antioxidant, a pigment, a dye, and a lubricant. , leveling agent, anti-blocking agent, conductive agent, etc. The binder is not particularly limited, and examples thereof include a phenol resin, an epoxy resin, a urea resin, a polyurethane, an alkyd resin, and the like. Examples of the curing agent include an isocyanic curing agent, an epoxy curing agent, a nitrogen cyclopropane curing agent, a carbodiimide curing agent, and an oroxazoline curing agent.

The release film of the present invention is an article having at least one side of a release layer formed of the coating agent of the present invention, which can be cured by applying the coating agent of the present invention to various conventional substrate films and heating or drying. Got it.

The substrate film can be exemplified by, for example, polycarbonate, polymethyl methacrylate, polystyrene, polyethylene terephthalate (PET), polyimine, polyene, nylon, epoxy resin, A film formed of a plastic such as melamine resin, cellulose triacetate, ABS resin, AS resin or norbornene resin. The substrate film may also be subjected to surface treatment (corona discharge, etc.). Among these, polyethylene terephthalate is preferred from the viewpoints of properties such as transparency, dimensional stability, mechanical properties, and chemical resistance. These plastic films may also be coated on one or both sides with a coating agent other than the thermosetting release coating agent of the present invention.

The peeling layer (cured film) is obtained by applying the thermosetting release coating agent of the present invention to various substrates, heating, drying, etc., and the thickness after hardening is It is preferably about 0.01 to 10 μm and about 0.1 to 5 μm.

The coating method is not particularly limited, and various conventional means are used. Specifically, for example, a roll coater, a reverse roll coater, a gravure coater, a knife coater, a rod coater, or the like can be exemplified.

The heating and drying conditions are not particularly limited. The coating agent of the present invention is usually hardened at about 90 to 130 ° C and about 30 seconds to 2 minutes, and the formation conditions of the general coating film are usually about 150 to 190 ° C and about 1 minute to 5 minutes. In view of the above differences, it is known that the coating agent of the present invention is hardened at a relatively low temperature. Therefore, the coating agent is suitable for a plastic film which is easily deformed by heat, particularly a polyethylene terephthalate film.

The use of the release film of the present invention may, for example, be a release film for a manufacturing step of a ceramic green sheet, a synthetic leather, a decorative sheet, a carbon fiber prepreg, a printed circuit board, or the like, a release film for a transfer-related product, or a polarizing plate. It is a peeling film for protecting the adhesive layer, such as a phase difference plate.

[Examples]

In order to more specifically illustrate the present invention, the following examples and comparative examples are given, but the present invention is not limited to the examples. In each case, unless otherwise indicated, the parts and % are based on the weight basis.

<Preparation of thermosetting peeling coating agent>

Example 1

99 parts by weight of NIKALAC MX-45 (per ether type methylated butylated melamine resin, manufactured by Sanhe Chemical Co., Ltd.) and (F) component PHF-33 (12-hydroxyl group) 1 part by weight of a self-condensation product of stearic acid, manufactured by Ito Oil Co., Ltd., and 4 parts by weight of p-toluenesulfonic acid of the component (C), and diluted with 333 parts by weight of toluene and 83 parts by weight of isopropyl alcohol. It was prepared to have a solid content concentration of 20% to obtain a thermosetting peeling coating agent (hereinafter, also referred to as a coating agent).

Examples 2 to 13 and Comparative Examples 1 to 6

The manufacturing procedure was the same as in Example 1 except that the composition was changed to the components in Table 1.

<Production of release film>

The coating agent of Example 1 was applied to a polyethylene terephthalate film (film thickness: 50 μm, "Lumirror T60" manufactured by Toray Industries, Inc.) to form a cured film of 1 μm, and dried at 120 ° C for 1 minute. A release film was obtained. The coating agents of the other examples and comparative examples were also subjected to the same method to obtain a release film.

(film appearance)

With respect to the production of the release film of the above Example 1, the appearance of the cured film was observed, and the appearance of the coating film was evaluated on the following basis. The release films in the other examples and comparative examples were also evaluated on the same basis.

○: A transparent and smooth cured film was obtained.

×: The cured film has a white turbidity phenomenon, or the cured film has irregularities due to an undissolved coating agent.

(solvent resistance)

The cured film of the release film of Example 1 was wiped with a cotton swab impregnated with methyl ethyl ketone, and the number of round trips required until the substrate was exposed was measured to evaluate the solvent resistance of the cured film. The release film in the other examples and comparative examples was also evaluated for its solvent resistance in the same manner.

○: The surface of the base film (polyethylene terephthalate film) was not exposed even if it was rubbed 50 times or more.

△: The surface of the base film was exposed by rubbing 10 to 49 times.

X: The surface of the base film was exposed by rubbing 1 to 9 times.

(Peel force)

The cured film of the release film of Example 1 and the polyester adhesive tape (31B tape manufactured by Nitto Denko Co., Ltd.: 25 mm width) were bonded to each other while being pressed by a roll of 2 kg, and stored at 23 ° C for 1 hour. Next, the force (N/25 mm) required for stretching and peeling the tape at an angle of 180° and a peeling speed of 0.3 m/min was measured. The peeling force of the peeling films in the other examples and comparative examples was also measured in the same manner.

【Table 1】

The unit of the compounding amount of Table 1 is part by weight. The abbreviations and notes in Table 1 are as follows:

(1) Since the solvent resistance was poor, the peeling force was not evaluated.

(2) Since the appearance of the coating film was uneven or white, the solvent resistance and peeling force were not evaluated.

(abbreviation and details of the compound)

NIKALAC MX-45: Fully ether methylated butylated melamine resin, manufactured by Sanhe CHEMICAL Co., Ltd.

CYMEL 303LF: a fully ether type methylated melamine resin manufactured by Allnex Japan Inc., Japan.

PHF-33: Self-condensate of 12-hydroxystearic acid (number average molecular weight 1,800), manufactured by Ito Oil Co., Ltd.

PCF-30: Self-condensation of castor oil fatty acid (number average molecular weight 1,600), manufactured by Ito Oil Co., Ltd.

12-hydroxystearic acid: manufactured by Ito Oil Co., Ltd.

KURARAY Polyol F-3010: Polyester polyol (number average molecular weight 3,000), manufactured by Kuraray Co., Ltd.

Pripol 2033: hydrogenated dimer diol (number average molecular weight 540), manufactured by Croda Japan KK.

PIROIRU 1010S: Long chain alkyl side chain type polymer, manufactured by LION SPECIALTY CHEMICALS CO., LTD.

URIC F-97: Castor oil is a denatured polyol, manufactured by Ito Oil Co., Ltd.

Claims (10)

A thermosetting release coating agent comprising: a melamine resin (A), a self-condensate (B) of an aliphatic hydroxy acid (b) having 12 to 24 carbon atoms, and an acid catalyst (C). The thermosetting release coating agent according to the first aspect of the invention, wherein the component (A) contains a constituent unit derived from methylated melamine and/or butylated melamine. The thermosetting release coating agent according to the first or second aspect of the invention, wherein the component (B) is a self-condensation product of an aliphatic hydroxy acid having a carbon number of 18. The thermosetting release coating agent according to any one of claims 1 to 3, wherein the content of the component (B) is 100% by weight based on the total solid content of the release coating agent. ~50% by weight. The thermosetting release coating agent according to any one of claims 1 to 4, wherein the component (C) is an organic sulfonic acid and/or an organic phosphoric acid. The thermosetting release coating agent according to any one of claims 1 to 5, wherein the content of the component (C) is 100% by weight based on the total solid content of the release coating agent. ~10% by weight. The thermosetting release coating agent according to any one of claims 1 to 6, further comprising a polyol (D). The thermosetting release coating agent according to claim 7, wherein the weight ratio of the component (A) to the component (D) is 90/10 to 30/70. A release film comprising a cured film and a plastic film formed of the thermosetting release coating agent according to any one of claims 1 to 8. The release film according to claim 9, wherein the plastic film is a polyethylene terephthalate film.