JP2000119992A - Active energy ray-hardenable resin composition for paper and its hardened material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an active energy ray-hardenable resin composition for paper without generating curl or crack when applying it on paper and hardening the paper by irradiating it with active energy rays by mixing a (meth)acrylate of bisphenol-type epoxy resin with a specific imide (meth)acrylate. SOLUTION: This resin composition for paper hardening by irradiating active energy rays such as ultraviolet rays or electron beams is obtained by blending 5-80 wt.%, preferably 8-50 wt.% of a (meth)acrylate of bisphenol-type epoxy resin with 5-60 wt.%, preferably 10-50 wt.% of imide (meth)acrylate expressed by the formula (R is H or methyl) and a photopolymerization initiator as an optional component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active energy ray-curable resin composition useful for coating paper, and more particularly to a resin composition which is cured in a very short time by irradiation with an active energy ray such as an ultraviolet ray or an electron beam. The present invention relates to an active energy ray-curable resin composition which is excellent in adhesion of a cured product to paper, does not generate cracks when folded, and is excellent in imparting gloss to paper, and a cured product thereof.

[0002]

2. Description of the Related Art In recent years, active energy ray-curable resin compositions which are cured by active energy rays have been actively studied, and among them, printing inks, clear varnishes,
Practical application is being promoted in the fields of paints, adhesives, resists and the like. These are monomers and prepolymers having radical polymerizability and, if necessary, a photopolymerization initiator, an organic solvent,
It is made of pigment and the like.

[0003]

The active energy ray-curable resin composition is instantaneously cured by irradiation with the active energy ray, so that an internal stress is generated in the cured film.
For this reason, those obtained by applying and curing these curable resin compositions are liable to be cracked when curled or bent, and have poor adhesion and insufficient gloss.

[0004]

Means for Solving the Problems The present inventor has conducted intensive studies to improve these drawbacks. As a result, the curing speed is high, the workability such as adhesion to paper and bending properties is excellent, and the gloss is good. An active energy ray-curable resin composition was invented. That is, the present invention provides (1) a bisphenol-type epoxy resin (meth) acrylate (A),

[0005]

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(In the formula (1), R represents a hydrogen atom or a methyl group.) An imide (meth) acrylate (B) represented by the formula (1) and a photopolymerization initiator (C) as an optional component. Active energy ray-curable resin composition for paper, (2) a cured product of the active energy ray-curable resin composition for paper of (1), (3) paper covered with a cured product film of (2), About.

The (meth) acrylic acid ester (A) of the bisphenol type epoxy resin used in the present invention is a reaction product of the bisphenol type epoxy resin and (meth) acrylic acid. Examples of the bisphenol type epoxy resin include a bisphenol A type epoxy resin and a bisphenol F type epoxy resin. These are known compounds. The amount of the component (A) to be used is preferably 5 to 80% by weight, more preferably 8 to 50% by weight in the composition of the present invention.

As the imide (meth) acrylate (B) represented by the formula (1) used in the present invention, for example, a compound wherein R is a hydrogen atom in the above formula (1) (Toa Gosei Chemical Industry Co., Ltd.) And Aronix TOA-1429) and compounds wherein R is a methyl group. Its use amount is preferably 5 to 60% by weight of the resin composition,
Particularly, 10 to 50% by weight is preferable. By adding this component, the flexibility increases and the bendability is excellent,
Good gloss.

The photopolymerization initiator (C) used as an optional component includes, for example,

[0010]

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Copolymerizable polymerization initiators such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone,
-Methyl-1- [4- (methylthio) phenyl] -2-
Acetophenones such as morpholino-propan-1-one and N, N-dimethylaminoacetophenone; 2,4-diethylthioxanthone, 2-chlorothioxanthone,
Thioxanthones such as isopropylthioxanthone;
Ketals such as benzyl dimethyl ketal and acetophenone dimethyl ketal; benzophenones such as benzophenone, methylbenzophenone, 4,4'-bisdiethylaminobenzophenone and 4-benzoyl-4'-methyldiphenyl sulfide; 2,4,6-trimethylbenzoyldiphenyl And phosphine oxides such as phosphine oxide. These can be used alone or in combination of two or more.

Further, photosensitizers can be used alone or in combination of two or more. Examples of the photosensitizer include N, N-dimethylaminobenzoic acid ethyl ester,
Tertiary amines such as N, N-dimethylaminobenzoate, triethylamine, triethanolamine and the like can be mentioned.

In the composition of the present invention, the amount of component (C) used is preferably from 0 to 15 parts by weight, more preferably from 1 to 10 parts by weight, based on 100 parts of the total of components (A) and (B). It is preferred to use.

In the resin composition of the present invention, an ethylenically unsaturated compound other than the components (A) and (B) can be used if necessary. Examples of the ethylenically unsaturated compound other than the components (A) and (B) include N-vinylacetamide,
Monofunctional (meth) acrylate monomer, polyfunctional (meth)
Compounds having a (meth) acrylate group other than the above components (A) and (B), such as an acrylate monomer and a polymer (meth) acrylate, are exemplified. The amount of the ethylenically unsaturated compound to be used is preferably 0 to 60% by weight, particularly preferably 10 to 50% by weight in the composition. These ethylenically unsaturated compounds are readily available on the market.

The monofunctional (meth) acrylate monomer is a monomer having one (meth) acrylate group in the molecule, for example, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate, 2-hydroxy-3-phenyloxypropyl acrylate, acryloylmorpholine, And dicyclopentanyloxyethyl acrylate.

The polyfunctional (meth) acrylate monomer is a monomer having two or more, preferably two to six, (meth) acrylate groups in the molecule, such as dioxane glycol diacrylate (manufactured by Nippon Kayaku Co., Ltd., KAYAR
ADR-604), polyethylene glycol diacrylate, tripropylene glycol diacrylate,
Examples include acrylates of 1,6-hexanediol diglycidyl ether, trimethylolpropane triacrylate, trimethylolpropane polyethoxytriacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol penta, and hexaacrylate.

Examples of the polymer (meth) acrylate include modified (meth) acrylates such as polyurethane, polyester, silicone resin, alkyd resin, and phenol resin.

Although the composition of the present invention may or may not contain an organic solvent, it may be preferable to use an organic solvent for viscosity adjustment depending on the use. When an organic solvent is added, it is desirable to remove it with a hot air drier after coating. For this purpose, the smaller the amount, the better. The solvent has a boiling point of 70 to remove by hot air drying after coating.
A solvent that is as harmless and safe as possible at ~ 150 ° C is desirable.
For example, ethyl acetate, butyl acetate, toluene, xylene, methyl ethyl ketone, methyl butyl ketone, and the like can be used. Further, it can be used as a mixed solvent with another solvent. The preferred viscosity is

The resin composition of the present invention may further comprise a pigment, a dye, an antifoaming agent, a leveling agent, a slipping agent, a matting agent, an antioxidant, a light stabilizer, an ultraviolet absorber, a polymer compound (for example, Acryl polymer, styrene polymer, polyurethane elastomer, polyester elastomer, etc.).

The resin composition of the present invention can be obtained by uniformly mixing and dissolving each component. This composition is usually obtained as a liquid. Its preferred viscosity is 1
It is about 00 to 1000 cps (25 ° C.). The cured product of the resin composition of the present invention can be obtained by irradiating the resin composition of the present invention with an active energy ray according to a conventional method. Ultraviolet rays, electron beams and the like can be used as the active energy rays.

The resin composition of the present invention is useful for paper coating, especially for paper overcoating. It is also useful for printing inks for paper and the like. When the resin composition of the present invention is used for coating paper, for example, a roll coater, an offset printing machine, a flexographic printing machine, and the like, on a paper on which another printing ink or a coating liquid has been printed or applied, is used. It is preferably coated with a thickness of 1 to 6 μm, and after containing the solvent, after removing the solvent, is covered with a cured film by irradiating an active energy ray such as an ultraviolet ray or an electron beam by an ordinary method. You can get torn paper.

[0022]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. Parts in Synthesis Examples and Examples are parts by weight. (Synthesis of (meth) acrylate (A) of bisphenol type epoxy resin) Synthesis Example 1 Epomic R-304 (bisphenol A type epoxy resin, manufactured by Mitsui Petrochemical Industries, Ltd., epoxy equivalent: 916.
8) 800 parts, 59.2 parts of acrylic acid, 0.86 parts of hydroquinone monomethyl ether, 2-hydroxy-3-
860 parts of phenyloxypropyl acrylate and 8.6 parts of triphenylphosphine were charged and reacted at 90 ° C. for 30 hours to obtain a mixture containing an acrylate (A) of a bisphenol-type epoxy resin.

Synthesis Example 2 Epomic R-140 (bisphenol A type epoxy resin, manufactured by Mitsui Petrochemical Industries, Ltd., epoxy equivalent: 189)
1215 parts, 458.6 parts of acrylic acid, 0.84 parts of hydroquinone monomethyl ether and 0.6 parts of triphenylphosphine were charged, reacted at 90 ° C. for 20 hours, and an acrylic acid ester of bisphenol type epoxy resin (A)
I got

Example 1 30 parts of a mixture containing an acrylate of a bisphenol-type epoxy resin obtained in Synthesis Example 1, 40 imide acrylates (Aronix TOA-1429: a compound in which R is a hydrogen atom in the above formula (1)) 40 Parts, 15 parts of tetrahydrofurfuryl acrylate, 10 parts of polyethylene glycol diacrylate and 5 parts of 1-hydroxycyclohexyl phenyl ketone were mixed to obtain a resin composition A of the present invention. Table 1 shows the properties of the cured product.

Example 2 20 parts of the acrylate ester of the bisphenol-type epoxy resin obtained in Synthesis Example 2, 45 parts of the imide acrylate used in Example 1, and phenyloxyethyl acrylate 20
Parts, 1,6-hexanediol diglycidyl ether diacrylate (10 parts) and 1-hydroxycyclohexyl phenyl ketone (5 parts) were mixed, and the resin composition B of the present invention was mixed.
I got Table 1 shows the properties of the cured product.

Example 3 A composition C of the present invention was obtained in the same manner as in Example 1 except that 5 parts of 1-hydroxycyclohexylphenyl ketone was excluded from the composition of Example 1. Table 1 shows the properties of the cured product.

Comparative Example 1 30 parts of the mixture containing the acrylate of the bisphenol type epoxy resin obtained in Synthesis Example 1, 15 parts of tetrahydrofurfuryl acrylate, 50 parts of polyethylene glycol diacrylate and 5 parts of 1-hydroxycyclohexyl phenyl ketone were mixed. Then, a resin composition D was prepared.
Table 1 shows the properties of the cured product.

Table 1 Example Comparative Example Resin composition ABCD Evaluation item Curing speed ○ ○ ○ ○ Gloss ○ ○ ○ ○ Hardness ○ ○ ○ × Adhesion ○ ○ ○ × Overall evaluation ○ ○ ○ ×

Evaluation method Curing speed: A resin composition was applied to a paper coated with an aqueous ink at a thickness of 5 μm by a flexographic printing machine, and this was applied to one high-pressure mercury lamp (2 kW, 80 w / cm) using an ultraviolet irradiator. Cured at a conveyor speed of 5 m / min.
(Note that the resin composition C in Table 1 is an electron beam 3 Mrad.
And cured. The curing speed was determined based on the presence or absence of surface tack after curing. ○ ・ ・ ・ ・ No tack △ ・ ・ ・ ・ Tack a little × ・ ・ ・ ・ Tack considerably

Gloss: The gloss after curing was visually determined. ○ ... Excellent gloss. × ・ ・ ・ ・ Insufficient gloss

Hardness: Judgment by cracking of the folded paper resin part after curing ○ ・ ・ ・ ・ No cracking × ・ ・ ・ ・ Severe cracking Adhesion: After curing, apply cellophane tape to the coated surface and cure the peeling resin When the film and the water-based ink portion were peeled off from the underlying paper or when only the cellophane tape was peeled off, it was evaluated as ○, and when only the applied cured film was peeled off, it was evaluated as ×.

As is clear from Table 1, the resin composition of the present invention has good curability, and the cured product has good adhesion, flexibility, and excellent gloss.

[0033]

By using the active energy ray-curable resin composition for paper of the present invention, the viscosity can be reduced and high-speed coating can be performed. To improve. Further, a cured product having excellent adhesion and flexibility and excellent gloss can be obtained.

Claims (3)

[Claims] 1. A (meth) -based bisphenol type epoxy resin
Acrylic ester (A), formula (1) (Wherein, R represents a hydrogen atom or a methyl group) An imide (meth) acrylate represented by the formula (B), a photopolymerization initiator as an optional component, and (C): a paper activity. Energy ray-curable resin composition. 2. A cured product of the resin composition according to claim 1. 3. A paper covered with the cured product film according to claim 2.