JPH11148045A - Active energy light-curable coating composition and formation of coating using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition capable of forming coating films having high hardness and excellent adhesivity by compounding an oxetane functional group-containing resin, a polyepoxide, a radically polymerizable double bond-containing compound or resin, and a photopolymerization initiator. SOLUTION: This coating composition contains (A) a resin containing on the average two oxetane functional groups of the formula (R1 is H, a 1-6C alkyl, F, a 1-6C fluoroalkyl, allyl, an aryl or the like) in the molecule, (B) a polyepoxide, (C) a compound or resin containing one or two radically polymerizable double bonds in the molecule, and (D) a photocationic/radical polymerization initiator or a mixture of a photocationic polymerization initiator with a photoradical polymerization initiator as essential components. The components B and C are compounded in amounts of about 0.1-500 pts.wt. and about 0.1-500 pts.wt., respectively, per 100 pts.wt. of the component A as solid contents, and the component C is compounded in an amount of 0.01-20 pts.wt. per 100 pts.wt. of the total amount of the components A, B and C as solid contents.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel active energy ray-curable coating composition and a method for forming a film using the same.

[0002]

2. Description of the Related Art Conventionally, active energy ray-curable resin compositions which are cured by active energy rays such as ultraviolet rays and electron beams have been widely used for applications such as paints, inks and adhesives. In general, paints such as thermosetting paints and lacquers are not sufficiently cured immediately after finishing, and after a certain period of time (cooling, drying), the product is wound up, stacked and transported. Has the disadvantage that productivity is poor. On the other hand, the active energy ray-curable resin composition can be cured in seconds and does not require heating, thereby enabling high-speed curing and drying that could not be achieved with thermosetting paints and lacquers, and is suitable for this. Widely used for applications.

However, since conventional active energy ray radically polymerizable vinyl compounds are inhibited from surface hardening by oxygen, they are usually cured by active energy ray irradiation in the presence of an inert gas such as nitrogen, The amount is large. For this reason, there are problems that the cost is increased due to the necessity of special equipment, the inert gas is not good for the human body, and the productivity is poor.

[0004] Among active energy ray-curable resin compositions, those in which a cationic photopolymerization initiator is blended with an epoxy resin are known as those which are less susceptible to surface curing inhibition by oxygen. There was a disadvantage that the membrane performance was insufficient.

[0005] Further, the conventional cured film still has problems such as insufficient surface hardness and poor adhesion to a plastic film such as polyethylene terephthalate.

[0006]

SUMMARY OF THE INVENTION The present invention is to develop a curable resin composition by irradiation with active energy rays which is excellent in surface hardness, adhesion, curability, film performance and productivity in the presence of oxygen. It is done for the purpose of doing.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned disadvantages of the prior art. As a result, the problems of the prior art can be solved by using an oxetane functional group, an epoxy group, and a radical polymerizable double bond as a cross-linking functional group, and adding a photocationic polymerization initiator and a photoradical polymerization initiator thereto. They have found that they can do this and have completed the present invention.

According to the present invention, (A) the following general formula (I)

[0009]

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(Wherein, R ₁ is a hydrogen atom, having 1 to 6 carbon atoms)
An oxetane functional group represented by an alkyl group, a fluorine atom, a fluoroalkyl group having 1 to 6 carbon atoms, an allyl group, an aryl group, an aralkyl group, a furyl group or a phenyl group) in a molecule. Resin, (B) polyepoxide, and (C) radical polymerizable double bond.
A compound or resin containing one or more compounds in the molecule, and (D) a photopolymerization initiator that simultaneously generates cations and radicals by irradiation with active energy rays or a photopolymerization initiator that generates cations by irradiation with active energy rays. An active energy ray-curable coating composition (hereinafter referred to as "active energy ray-curable coating composition (1)") comprising a mixture of photopolymerization initiators that generate radicals as an essential component. ), (E) the following general formula (I)

[0011]

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(Wherein R ₁ is a hydrogen atom, having 1 to 6 carbon atoms)
Oxetane functional group represented by an alkyl group, a fluorine atom, a fluoroalkyl group having 1 to 6 carbon atoms, an allyl group, an aryl group, an aralkyl group, a furyl group or a phenyl group) and an epoxy group in the same molecule. Resin, (C)
A compound or resin containing one or more radically polymerizable double bonds in one molecule, and (D) a photopolymerization initiator which simultaneously generates cations and radicals by irradiation with active energy rays, or by irradiation with active energy rays An active energy ray-curable coating composition comprising a mixture of a photopolymerization initiator that generates cations and a photopolymerization initiator that generates radicals as an essential component (hereinafter referred to as an “active energy ray-curable coating composition”). Coating composition (2)) and the surface of the object to be coated with the active energy ray-curable coating composition, followed by irradiation with active energy rays to cure the composition. Provided.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The active energy ray-curable coating composition of the present invention can be cured by simultaneously conducting cationic polymerization and radical polymerization by irradiation with active energy rays such as ultraviolet rays and electron beams. Things.

The active energy ray-curable coating composition (1) of the present invention is described below. The active energy ray-curable coating composition (1) comprises a resin (A) having an oxetane functional group represented by the formula (I) as a crosslinking functional group, a polyepoxide (B), and a compound having a radical polymerizable unsaturated group or It is characterized in that the resin (C) is contained as a main component.

Oxetane functional group-containing resin (A): In the definition of R ₁ in the formula (I), the “alkyl group having 1 to 6 carbon atoms” may be linear or branched; For example, methyl, ethyl, n-propyl, isopropyl,
n-butyl, isobutyl, sec-butyl, tert-
Butyl, n-hexyl and the like. "C 1-6
Is a group in which at least one hydrogen atom of the above alkyl group is substituted with a fluorine atom, and examples thereof include fluoropropyl, fluorobutyl, trifluoropropyl and the like. The “aryl group” may be monocyclic or polycyclic, and the aromatic ring may be substituted with one or more alkyl groups having 1 to 6 carbon atoms, for example, phenyl, toluyl , Xylyl, naphthyl and the like. An “aralkyl group” is an aryl-alkyl group in which the aryl portion and the alkyl portion have the above-mentioned meanings, such as a benzyl group and a phenethyl group.

As R ₁ , an alkyl group having 1 to 6 carbon atoms, especially 1 to 4 carbon atoms, such as methyl and ethyl, is preferred.

The oxetane functional group is bonded to the side chain or main chain of the resin (A) via an oxygen-containing bond such as an ether bond, an ester bond, or a urethane bond or a hydrocarbon containing one or more of these bonds. It is preferably bonded to

The oxetane functional groups can be present in the resin (A) at an average of at least about 2 or more, preferably about 3 to about 30 on average per molecule. If the number of the oxetane functional groups is less than about 2 per molecule on average, it is not preferable because the curability of the active energy ray is lowered.

The oxetane functional group-containing resin (A) has a number average molecular weight in the range of 1,000 to 150,000, preferably in the range of 3,000 to 100,000. When the number average molecular weight is less than 1,000, the durability of the coating film is inferior. On the other hand, when it exceeds 150,000, the finished appearance of the coating film is inferior.

The oxetane functional group-containing resin (A) has no particular limitation as long as it contains at least two oxetane functional groups in one molecule and has a number average molecular weight in the range of 1,000 to 150,000. Can be used. Specifically, for example, a polyester resin, an acrylic resin, a fluororesin, a silicon resin, an alkyd resin, a polyether resin, and modified resins thereof are included.

Representative examples of the method for introducing an oxetane functional group into the above resin are described below.

(1) Polybasic acids (eg, (phthalic anhydride), isophthalic acid, terephthalic acid, (maleic anhydride), adipic acid, azelaic acid, etc.) and polyhydric alcohols (eg, ethylene glycol, neopentyl glycol) Propylene glycol, 1,6-hexanediol, glycerin, pentaerythritol, trimethylolpropane, etc.) and, if necessary, a mixture of monobasic acid in the presence of an esterification catalyst to cause a polycarboxylic acid polyester resin. And then subjecting the obtained resin to an esterification reaction with a triol component such as trimethylolpropane to form the following formula derived from the triol component in the polyester resin.

[0023]

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A polyester resin having a cyclic polycarbonate produced by introducing the 1,3-diol residue of the above, followed by reacting the residue with diethyl carbonate, and subsequently decarbonating the polyester resin.

(2) A triol such as trimethylolpropane is reacted with diethyl carbonate to produce a hydroxyl group-containing cyclic carbonate, which is then decarbonated to give 3-ethyl having a hydroxyl group at one end and an oxetane functional group at the other end. −
A 3-hydroxymethyloxetane is prepared, and then a complementary functional group that reacts complementarily with the hydroxyl group of the oxetane but does not substantially react with the oxetane group, for example,
Resins having isocyanate groups, lower alkoxy groups (eg, methoxy, ethoxy), lower alkoxycarbonyl groups (eg, methoxycarbonyl, ethoxycarbonyl), etc. (eg, acrylic resins containing isocyanate groups, polyester resins containing methyl ester groups) Etc.).

(3) The functional group and the radical polymerizable unsaturated group (eg, acryloyl group, methacryloyl group, vinyl group, etc.) reacting complementarily with the above-mentioned 3-ethyl-3-hydroxymethyloxetane. Reacting with a saturated monomer to produce an unsaturated monomer having a radically polymerizable unsaturated group at one end of the molecule and an oxetane functional group at the other end, and then subjecting the unsaturated monomer to other radical polymerization if necessary. Unsaturated monomers (e.g.,
Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, alkyl or cycloalkyl esters of _C 1 _{-C 24} (meth) acrylic acid such as cyclohexyl (meth) acrylate s; 2-hydroxypropyl (meth) acrylate, caprolactone-modified (meth) such as hydroxyethyl acrylate (meth) C ₂ -C ₈ hydroxyalkyl esters of acrylic acid; (meth)
Carboxyl group-containing unsaturated monomers such as acrylic acid;
Aromatic vinyl compounds such as styrene, α-methylstyrene and vinyltoluene; fluorinated unsaturated monomers such as perfluorobutylethyl (meth) acrylate and perfluoroisononylethyl (meth) acrylate; and (meth) acrylamide Polymerizable amides; polymerizable nitriles such as (meth) acrylonitrile) and radicals (co)
Polymerized one.

(4) The above-mentioned hydroxyl-containing cyclic carbonate is reacted with the resin having the complementary functional group to introduce a cyclic carbonate into the resin, and then the cyclic carbonate is decarboxylated to be converted into an oxetane functional group.

(5) The above-mentioned hydroxyl-containing cyclic carbonate is reacted with the above-mentioned functional group which reacts complementarily and an unsaturated monomer containing a radically polymerizable unsaturated group, so that a radically polymerizable unsaturated group and a Producing an unsaturated monomer having a cyclic carbonate at the other end, and then subjecting the unsaturated monomer to radical (co) polymerization with the above-mentioned other radically polymerizable unsaturated monomer, if necessary,
(C) After introducing a cyclic carbonate into a polymer, the cyclic carbonate is converted into an oxetane functional group by decarboxylation.

Polyepoxide (B): The polyepoxide (B) used in the present invention is a resin having an average of about 2 or more, preferably about 2 to 10 on average, epoxy groups in one molecule. When the number of the epoxy groups is less than about 2 in one molecule on average, it is not preferable because the curability of the active energy ray is lowered.

The polyepoxide (B) has a number average molecular weight of about 120 to 200,000, preferably about 240
Those within the range of ~ 80,000 are preferred. When the number average molecular weight is less than about 120, the durability of the coating film is reduced, and when the number average molecular weight is more than about 200,000, there is a disadvantage that coating workability is deteriorated, which is not preferable.

Specific examples of the polyepoxide (B) include:
For example, glycidyl group-containing ethylenically unsaturated monomers such as glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, and allyl glycidyl ether;
An epoxy group-containing ethylenically unsaturated monomer such as an alicyclic epoxy group-containing ethylenically unsaturated monomer such as 3,4-epoxycyclohexylmethyl (meth) acrylate; (Co) polymers obtained by radical (co) polymerization of monomers; glycidyl ether compounds such as diglycidyl ether, 2-glycidylphenyl glycidyl ether, and 2,6-diglycidylphenyl glycidyl ether; vinylcyclohexenedioxide, lemonendi Compounds containing a glycidyl group and an alicyclic epoxy group such as oxide; dicyclopentadienedioxide, bis (2,3-epoxycyclopentyl) ether, epoxycyclohexene carboxylic acid ethylene glycol diester, bis (3,4-epoxy) B hexyl methyl) adipate, 3,4-epoxycyclohexylmethyl-3,4-
Alicyclic epoxy group-containing compounds such as epoxycyclohexanecarboxylate and 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate; bisphenol A epoxy resin; bisphenol F epoxy resin Cresol novolak type epoxy resin; phenol novolak type epoxy resin and the like.

Radical polymerizable unsaturated group-containing compound or tree
Fat (C): The compound containing a radically polymerizable unsaturated group or the resin (C) used in the present invention has one or more double bonds in one molecule of a polymerizable unsaturated group that can be radically polymerized by irradiation with active energy rays. It is a compound or resin containing two or more, and includes a radical polymerizable unsaturated group-containing monomer, a radical polymerizable unsaturated group-containing oligomer, a radical polymerizable unsaturated group-containing resin, and the like.

Examples of the radical polymerizable unsaturated group-containing monomer include styrene, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and lauryl (meth) acrylate. , Cyclohexyl (meth) acrylate, cyclohexenyl (meth) acrylate, 2-hydroxy (meth) acrylate, hydroxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, ε-caprolactone-modified tetrahydrofurfuryl (meth) acrylate, phenoxyethyl (Meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate Rate, isobornyl (meth)
Acrylate, benzyl (meth) acrylate, ε-caprolactone-modified hydroxyethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth)
Acrylate, 2-hydroxy-3-butoxypropyl (meth) acrylate, monohydroxyethyl phthalate (meth) acrylate, Aronix M110 (product of Toagosei Co., Ltd.), N-methylol (meth) acrylamide, N-methylol (meth) Acrylamide butyl ether, acryloyl morroline, dimethylaminoethyl (meth) acrylate and the like can be mentioned.

As the bifunctional polymerizable monomer, for example,
Ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl Glycol di (meth) acrylate, 1,4-butanediol di (meth)
Acrylate, 1,6-hexanediol di (meth) acrylate, bisphenol A ethylene oxide-modified di (meth) acrylate, bisphenol A propylene oxide-modified di (meth) acrylate, 2-hydroxy-1-acryloxy-3-methacryloxypropane, triacrylate Cyclodecane dimethanol di (meth) acrylate,
Di (meth) acryloyloxyethyl acid phosphate, Kayarad HX-220, 620, Kayarad R-604, MANDA (all products of Nippon Kayaku Co., Ltd.) and the like.

Examples of the trifunctional or higher polymerizable monomer include trimethylolpropane tri (meth) acrylate, trimethylolpropaneethylene oxide-modified tri (meth) acrylate, trimethylolpropanepropylene oxide-modified tri (meth) acrylate, and glycerin triacrylate. (Meth) acrylate, glycerin ethylene oxide modified tri (meth) acrylate, glycerin propylene oxide modified tri (meth) acrylate,
Examples include pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, isocyanuric acid ethylene oxide-modified triacrylate, dipentaerythritol hexa (meth) acrylate, and the like. In addition, N-vinyl-2-pyrrolidone,
Monomers having a nitrogen-containing heterocycle such as vinylpyridine; 2-hydroxyethyl (meth) acrylate, 2-
Adducts of a hydrogen group-containing monomer such as hydroxypropyl (meth) acrylate with a polyisocyanate such as butyl isocyanate and phenyl isocyanate; and adducts of phosphoric acid with the above-mentioned hydroxyl group-containing monomer.

Examples of the radical polymerizable unsaturated group-containing oligomer include ethylene glycol di (meth) acrylate, diethylene glycol (meth) acrylate, triethylene glycol (meth) acrylate, tetraethylene glycol (meth) acrylate, and 1,3.
-Butylene glycol di (meth) acrylate, 1,4
-Butanediol diacrylate, glycerin di (meth) acrylate, glycerin tri (meth) acrylate, trimellilol propane di (meth) acrylate,
Trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, hydroxyisocyanurate tri (meth) acrylate , Neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, glycerol allyloxydi (meth) acrylate, 1,1,1-tris (hydroxymethyl)
Oligomers such as di-, tri-, and tetra-vinyl compounds such as ethanedi (meth) acrylate and 1,1,1-tris (hydroxymethyl) ethanetri (meth) acrylate; ethylene glycol, glycerin, butylene glycol, trimethylolpropane, Products obtained by reacting (meth) acrylic acid with an adduct of a polyhydric alcohol such as pentaerythritol, neopentyl glycol, or 1,6-hexanediol with ethylene oxide or propylene oxide; and a phosphorus-containing polymerizable unsaturated oligomer. Can be

Examples of the radical polymerizable unsaturated group-containing resin include a resin obtained by condensing (meth) acrylic acid with polyester, an ethylenically unsaturated group-containing urethane resin,
Ethylenically unsaturated group-containing epoxy resin, ethylenically unsaturated group-containing phosphorus epoxy resin, ethylenically unsaturated group-containing acrylic resin, ethylenically unsaturated group-containing silicone resin,
Examples include melamine resins containing an ethylenically unsaturated group.

The above radical polymerizable unsaturated group-containing compound or resin (C) can be used alone or in combination of two or more.

The oxetane functional group-containing resin (A) described above,
The compounding ratio of the polyepoxide (B) and the radical polymerizable unsaturated group-containing compound or resin (C) is such that the polyepoxide (B) is about 0.1 part by weight based on 100 parts by weight of the oxetane functional group-containing resin (A) on a solid basis. When the amount of the radical polymerizable unsaturated group-containing compound or resin (C) is about 0.1 to 500 parts by weight, preferably 10 to 200 parts by weight.
A range of 500 parts by weight, preferably a range of 10 to 200 parts by weight is suitable.

Photopolymerization initiator (D): The photopolymerization initiator (D) used in the present invention is a photopolymerization initiator (hereinafter referred to as a photopolymerization initiator which simultaneously generates cations and radicals upon irradiation with active energy rays.
A photopolymerization initiator (hereinafter referred to as "photocationic / radical polymerization initiator") or a photopolymerization initiator that generates cations by irradiation with active energy rays (hereinafter referred to as a "photocationic polymerization initiator") and a photopolymerization initiator that generates radicals (hereinafter referred to as "photocationic / radical polymerization initiator") , "Photo-radical polymerization initiator").

Examples of the photocation / radical polymerization initiator include compounds represented by the following formulas (III) to (XI).

[0042] _{^{Ar 2 I + · X - (}} III) [ wherein, Ar represents an aryl group such as phenyl group, X ^- is PF ₆ ^-, SbF ₆ ^-, or AsF ₆ ^- represents a] Ar ₃ S ⁺ · ^X - (IV) [wherein, Ar and X ^- is the same as defined above]

[0043]

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Wherein R ³ is an aralkyl group having 7 to 15 carbon atoms or an alkenyl group having 3 to 9 carbon atoms, R ⁴ is a hydrocarbon group or hydroxyphenyl group having 1 to 7 carbon atoms, R ⁵ Represents an alkyl group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, and X ⁻ has the same meaning as described above.

[0045]

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Wherein Y ⁻ is PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆
^- or SbF ₅ (OH) ^- represents a]

[0047]

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[Wherein, X ^- has the same meaning as described above]

[0049]

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[Wherein, X ^- has the same meaning as described above]

[0051]

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[0052]

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Wherein R ⁶ and R ⁷ each independently represent an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms.

[0054]

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The above photocationic / radical polymerization initiators can be used alone or in combination of two or more.

Commercially available photocationic / radical polymerization initiators include, for example, Cyracure UVI-697.
0, UVI-6990, UVI-6974, UV
I-6950 (all, manufactured by Union Carbide, USA), SP-150, SP-170 (all, manufactured by Asahi Denka Kogyo), PI-2074 (Rhone Poulin, pentafluorophenyl borate toluylcumyl) Iodonium salt), FC-509 (manufactured by 3M), BBI-
102 (manufactured by Midori Kagaku).

The mixing ratio of the above-mentioned photocation / radical polymerization initiator is calculated based on the total weight of the components (A) to (C).
The amount is preferably 0.01 to 20 parts by weight, preferably 0.05 to 15 parts by weight, and more preferably 0.1 to 10 parts by weight based on parts by weight (solid content basis). If the compounding ratio is less than 0.01 part by weight, the curability, processability, etc. decrease, and if it exceeds 20 parts by weight, the storage stability, the finished appearance of the cured product, yellowing, etc. decrease, so neither is preferable. .

Examples of the photocationic polymerization initiator include compounds represented by the following formulas (XII) to (XVII).

[0059]

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[Wherein, X ^- has the same meaning as described above]

[0061]

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[Wherein R ² represents an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms, and n represents 0
Represents an integer of from 1 to 3, and X ^- has the same meaning as described above.

[0063]

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[Wherein, R ⁶ and R ⁷ each independently represent an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms]

[0065]

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[0066]

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Examples of commercially available photocationic polymerization initiators include Irgacure 261 (manufactured by Ciba Geigy).

Examples of the photoradical polymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, 2-methylbenzoin, benzyl,
Benzyl dimethyl ketal, diphenyl sulfide, tetramethyl thiuram monosulfide, diacetyl, eosin, thionine, Michler's ketone, anthracene, anthraquinone, chloranthraquinone, methyl anthraquinone, acetophenone, α-hydroxyisobutylphenone, p-isopropyl-α-hydroxyisobutylphenone, α Α′-dichloro-4-phenoxyacetophenone, 1-hydroxy-1-cyclohexylacetophenone, 2,2′-dimethoxy-2-phenylacetophenone, methylbenzoylformate, 2-methyl-1- [4- (methylthio) phenyl ] Conventionally known photoradical polymerization initiators such as 2-morpholinopropanone-1, thioxanthone and benzophenone can be mentioned.

The mixing ratio of the above-mentioned cationic photopolymerization initiator and photoradical polymerization initiator is in the range of 1: 100 to 100: 1, preferably 30: 100 to 100: 30. The mixing ratio of the mixture of the photocationic polymerization initiator and the photoradical polymerization initiator is 0.01 to 100 parts by weight (solid basis) of the components (A) to (C).
The range is preferably from 20 to 20 parts by weight, preferably from 0.05 to 15 parts by weight, more preferably from 0.1 to 10 parts by weight. If the compounding ratio is less than 0.01 part by weight, the curability, processability, etc., decrease, and if it exceeds 20 parts by weight, the storage stability,
None of them is preferable since the finished appearance, yellowing and the like of the cured product are reduced.

In order to accelerate the photopolymerization reaction by the photopolymerization initiator (D), a photosensitization accelerator may be used in combination with the photopolymerization initiator. Examples of photosensitizers that can be used in combination include tertiary amines such as triethylamine, triethanolamine and dimethylaminoethanol, alkylphosphines such as triphenylphosphine, and β-
And thioether-based photosensitizers such as thiodiglycol. Each of these photosensitizers can be used alone or in combination of two or more.
The amount is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the total components.

The active energy ray-curable coating composition (1) of the present invention may contain, if necessary, a coloring pigment, a filler, a blocking inhibitor, an ultraviolet absorber, an ultraviolet stabilizer, a surface conditioner, and an anti-peeling agent. And other additives such as resin.

The active energy ray-curable coating composition (2) of the present invention is described below. The active energy ray-curable coating composition (2) comprises a resin (E) having an oxetane functional group represented by the above formula (I) and an epoxy group in the same molecule as a crosslinking functional group, and a radical polymerizable unsaturated group. It is characterized in that the compound or the resin (C) is contained as a main component.

The oxetane functional group and the epoxy group have the same molecule
Resin (E) having therein : at least about 2 or more, preferably about 2 to about 100, more preferably about 2 to about 100 oxetane functional groups on average per molecule in resin (E). It can be present in a proportion of 50. If the number of the oxetane functional groups is less than about 2 per molecule on average, it is not preferable because the curability of the active energy ray is lowered.

On the other hand, the epoxy group has at least about 2 or more, preferably about 2 to about 100 on average, more preferably about 2 to about 50 on average per molecule in the resin (E).
Can be present in proportions. When the number of the epoxy groups is less than about 2 per molecule on average, it is not preferable because the curability of the active energy ray is lowered.

The type of the resin (E) is not particularly limited, and various resins such as an acrylic resin, a polyester resin, a polyurethane resin, and a polyether resin can be used. From the viewpoints of weather resistance and durability, in particular,
Acrylic resins are preferred.

The acrylic resin having both the oxetane functional group of the formula (I) and the epoxy group includes, for example, (a) a molecule having an oxetane functional group of the formula (I) at one end of a molecule and a radical polymerizable polymer at the other end. It can be produced by copolymerizing an unsaturated monomer having an unsaturated group and (b) an epoxy group-containing acrylic unsaturated monomer optionally with (c) another copolymerizable radically polymerizable unsaturated monomer.

As the oxetane functional group-containing unsaturated monomer (a), for example, the following formula (II)

[0078]

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In the formula, R ₁ has the same meaning as described above, and the 3-hydroxymethyloxetane compound of the formula (II) reacts complementarily with the hydroxyl group in the above formula (II), but substantially reacts with the oxetane group. It has a non-reactive complementary functional group, for example, isocyanate group, lower alkoxy group (for example, methoxy, ethoxy), lower alkoxycarbonyl group (for example, methoxycarbonyl, ethoxycarbonyl), etc. It can be obtained by reacting with an unsaturated compound having a saturated group, for example, an acryloyl group, a methacryloyl group or a vinyl group.

The compound of the above formula (II), for example, 3-ethyl-3-hydroxymethyloxetane is produced by reacting trimethylolpropane with diethyl carbonate to produce a hydroxyl group-containing cyclic carbonate, followed by decarboxylation. be able to.

Examples of the unsaturated compound which is reacted with the compound of the formula (II) include (meth) acrylic acid, methyl (meth) acrylate, isocyanatoethyl (meth) acrylate, m-isopropenyl- α, α
-Dimethylbenzyl isocyanate, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, methyl vinyl ether, ethyl vinyl ether and the like.

Examples of the above-mentioned epoxy group-containing acrylic unsaturated monomer (b) include glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate and the like.

Examples of the radically polymerizable unsaturated monomer (c) copolymerizable with the monomers (a) and (b) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, - ethylhexyl (meth) acrylate, C ₁ -C a (meth) acrylic acid such as cyclohexyl (meth) acrylate
₂₄ alkyl or cycloalkyl esters; C ₂ -C ₈ hydroxyalkyl esters of (meth) acrylic acid such as 2-hydroxypropyl (meth) acrylate and caprolactone-modified hydroxyethyl (meth) acrylate; (meth) acrylic acid Carboxyl group-containing unsaturated monomers such as styrene; α-methylstyrene, aromatic vinyl compounds such as vinyltoluene; and fluorine-containing unsaturated compounds such as perfluorobutylethyl (meth) acrylate and perfluoroisononylethyl (meth) acrylate. Saturated monomers; polymerizable amides such as (meth) acrylamide;
And polymerizable nitriles such as (meth) acrylonitrile. One or more of these monomers can be appropriately selected and used depending on the properties desired for the resin to be formed.

The resin (E) can be produced, for example, by subjecting a mixture of the above monomers (a), (b) and (c) to a radical polymerization reaction in an organic solvent in the presence of a polymerization initiator. .

As the organic solvent, the above-mentioned monomer (a)
Any inert organic solvent which does not substantially react with (c) can be used without particular limitation. Specifically, for example, aromatic solvents such as toluene and xylene; amyl acetate, propyl acetate, butyl acetate, methoxybutyl acetate,
Acetate solvents such as methyl acetoacetate, ethyl acetoacetate, methyl cellosolve acetate, cellosolve acetate, diethylene glycol monomethyl ether acetate, carbitol acetate; ether solvents such as dioxane, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol diethyl ether A ketone solvent such as acetone, methyl ethyl ketone and methyl isobutyl ketone; These can be used alone or in combination of two or more. In the organic solvent, it is preferable to use an aromatic solvent as a main component (50% by weight or more), and to use it in combination with a solvent other than the aromatic solvent as necessary.

As the polymerization initiator, a conventionally known radical polymerization initiator can be used without any particular limitation. Specifically, for example, benzoyl, di-tert-butyl hydroperoxide, tert-butyl hydroperoxide, cumyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, tert-butylperoxybenzoate, lauryl peroxide , Acetyl peroxide, te
rt-butyl-2-ethylhexanoate, tert-
Amyl peroxy-2-ethylhexanoate, 1,
Peroxides such as 1,3,3-tetramethylbutylperoxy-2-ethylhexanoate; and 2,2'-azobisisobutyronitrile, azobisdimethylvaleronitrile, azobiscyclohexanecarbonitrile and the like. Azo series and the like can be mentioned. These can be used alone or in combination of two or more.

The conditions of the radical polymerization reaction are not particularly limited, but are, for example, about 50 to 200 ° C., preferably about 70 to 200 ° C.
About 150 hours at a temperature range of about 1 to 24 hours, preferably about 5 hours.
A range from 10 to 10 hours is preferred.

The resin (E) having both the oxetane functional group and the epoxy group in one molecule may have a number average molecular weight of 1,000 to 150,000, preferably 3,
000 to 100,000.
When the number average molecular weight is less than 1,000, the durability of the coating film is inferior. On the other hand, when it exceeds 150,000, the finished appearance of the coating film is inferior.

The mixing ratio of the photopolymerization initiator (D) is generally 100 parts by weight (based on solid content) of the resin (E).
0.01 to 20 parts by weight, preferably 0.05
The range is preferably from 15 to 15 parts by weight, more preferably from 0.1 to 10 parts by weight. If the compounding ratio is less than 0.01 part by weight, the curability, processability, etc. decrease, and if it exceeds 20 parts by weight, the storage stability, the finished appearance of the cured product, yellowing, etc. decrease, so neither is preferable. .

In order to accelerate the photopolymerization reaction of the photopolymerization initiator (D), a photosensitization accelerator may be used in combination with the photopolymerization initiator. Examples of the photosensitizer that can be used in combination include alkylphosphine-based photosensitizers such as triphenylphosphine and thioether-based photosensitizers such as β-thiodiglycol. Each of these photosensitizers can be used alone or in combination of two or more. The compounding amount is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the component (D).

The active energy ray-curable coating composition (2) of the present invention may contain, if necessary, a coloring pigment, a filler, an antiblocking agent, an ultraviolet absorber, an ultraviolet stabilizer, a surface conditioner, and an anti-peeling agent. And other additives such as resin.

The active energy ray-curable coating composition of the present invention can be used for paints, inks, adhesives and the like.

The active energy ray-curable coating composition of the present invention can be applied to substrates such as paper, plastic, metal, and combinations thereof.

In the method of forming a coating film of the present invention, the above-mentioned active energy ray-curable coating composition wire is applied to the above-mentioned substrate surface so that the coating amount is 1 to 50 μm in the cured film thickness.
Then, it can be carried out by irradiating an active energy ray to cure.

The coating can be performed by a conventionally known method, for example, a spray, a roll coater, a gravure coater, a screen, or the like. The thickness of the applied coating film is about 1 to 50 microns in cured film thickness, preferably about 3 to 20 microns.
A range of microns is preferred.

Examples of the active energy ray include a mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a carbon arc, a metal halide lamp, a gallium lamp, and an excimer. it can. The irradiation amount of the ultraviolet ray is not particularly limited, but is usually about 10 to 2,000 mj / cm.
^It is preferably within the range of ² . In the case of an electron beam, an electron beam of 50 to 300 KeV is usually applied to an electron beam of 1 to 20 Mra.
Irradiation with d is preferred.

[0097]

The active-energy-ray-curable coating composition of the present invention has excellent storage stability and, when applied to an object to be coated, is cured by an active-energy ray to give a coating film having high hardness and excellent adhesion. Can be

[0098]

The present invention will be described more specifically below with reference to examples. “Parts” and “%” are based on weight, respectively.

Production Examples 1 to 4 85 parts of toluene was charged into a reaction vessel equipped with a thermometer, a thermostat, a stirrer, a reflux condenser and a dropping device, and heated to 110 ° C. while blowing nitrogen gas. From the monomer mixture shown in Table 1
-Azobis (2-methylbutyronitrile) in Examples 1 to
A solution in which 4 parts were dissolved in 2 and 3 parts in Examples 3 and 4 were added dropwise over 3 hours. After dropping, 110 ° C
For 2 hours to complete the reaction. Thereafter, the toluene is removed by distillation under reduced pressure, and the acrylic resin (a) is cooled and cooled.
To (d). Table 1 also shows the number average molecular weight of the obtained resin by GPC (gel permeation chromatography) measurement and the number of functional groups in one molecule.

[0100]

[Table 1]

Production Example 5 85 parts of ethyl alcohol was charged into a reaction vessel equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, a nitrogen gas distributor and a dropping device, and the temperature was raised to 80 ° C. while blowing nitrogen gas. did. Thereafter, a mixture of the following compounds was added dropwise over 3 hours while maintaining the temperature at 80 ° C.

Methyl methacrylate 10 parts Styrene 10 parts n-butyl acrylate 50 parts Glycidyl methacrylate 17 parts 2-hydroxyethyl acrylate 13 parts t-butyl peroctoate 5 parts After dropping, the mixture was left at 80 ° C. for 5 hours. Next, the following mixture was added and reacted at 80 ° C., and the resin acid value was 6 m
The reaction was terminated when gKOH / g was reached. Thereafter, ethanol was removed by distillation under reduced pressure, and the mixture was cooled to obtain a radical polymerizable unsaturated group-containing resin (e).

Methacrylic acid 14 parts Tetraethylammonium chloride 0.2 parts Parabenzoquinone 0.1 parts The number average molecular weight of the obtained resin (e) measured by GPC (gel permeation chromatography) was 3,500.
The number of oxetane functional groups in one molecule is 0, the number of epoxy groups is 0, and the number of radically polymerizable unsaturated groups is 2.45.
Was individual.

Examples 1 to 4 and Comparative Examples 1 to 4 Components (A) to (D) were mixed at room temperature in the proportions shown in Table 2,
Polyethylene terephthalate film (thickness 100μ)
m) was applied by a bar coater so that the dry film thickness became 10 μm, and then 2 μm was applied using a metal halide lamp.
Irradiation with ultraviolet light of 00 mj / cm ² resulted in a cured film.
The appearance, adhesion, pencil hardness, and surface curability of the obtained film were evaluated. Table 2 shows the results.

The test method in Table 2 is as follows.

Appearance of coating film: Abnormalities of the coating film such as cracks, cracks and reduction in gloss of the coating film were visually observed.

：: good, Δ: slightly poor smoothness and gloss, ×: poor smoothness and gloss.

Adhesion: 100 pieces of 1 × 1 mm grid are formed on the film with a sharp cutter to reach the material, and an adhesive cellophane tape is adhered to the surface, and the material is rapidly peeled off and adhered to the material. The score of the go board was evaluated visually.

Pencil hardness: This was measured according to JIS K-5400. The evaluation was performed by abrasion.

Surface curability: The cured film was rubbed with gauze impregnated with methyl ethyl ketone, and the glossiness of the rubbed surface was evaluated according to the following criteria.

◎: good even with 5 or more rubbings, ：: good with 2 to 4 rubbings, ×: poor gloss with one rubbing.

[0112]

[Table 2]

Claims (3)

[Claims] (A) The following general formula (I): (Wherein, R ₁ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a fluorine atom, a fluoroalkyl group having 1 to 6 carbon atoms,
(Showing an allyl group, an aryl group, an aralkyl group, a furyl group or a cyenyl group), a resin containing an average of two or more oxetane functional groups in one molecule, (B) a polyepoxide, and (C) a radical polymerizable double. Compound or resin containing one or more bonds in one molecule, and (D) a photopolymerization initiator that simultaneously generates cations and radicals by irradiation with active energy rays, or a photopolymerization that generates cations by irradiation with active energy rays An active energy ray-curable coating composition comprising, as an essential component, a mixture of an initiator and a photopolymerization initiator generating radicals. (E) The following general formula (I): (Wherein, R ₁ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a fluorine atom, a fluoroalkyl group having 1 to 6 carbon atoms,
A resin having an oxetane functional group represented by an allyl group, an aryl group, an aralkyl group, a furyl group or a phenyl group) and an epoxy group in the same molecule; and (C) a radical polymerizable double bond in one molecule. Compounds and / or resins containing one or two or more, and (D) a photopolymerization initiator that simultaneously generates cations and radicals by irradiation with active energy rays and / or a photopolymerization initiator that generates cations by irradiation with active energy rays An active energy ray-curable coating composition comprising, as an essential component, a mixture of a photopolymerization initiator generating radicals. 3. A method for forming a coating film, comprising applying the active energy ray-curable coating composition according to claim 1 or 2 to a surface of an object to be coated, and then irradiating the composition with an active energy ray.