JP2002241646A - Resin composition for coating curable with activated energy beam and coating curable with activated energy beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for coating curable with activated energy beam that has good storage stability and can form effective coating layer giving excellent abrasion resistance, surface hardness and adhesion to plastics. SOLUTION: The objective resin composition for coating curable with activated energy beam comprises a urethane (meth)acrylate (I) including 5 or more (meth)acryloyl units on the average and is produced by allowing (A) a (meth) acrylate bearing a hydroxyl and two or more (meth)acryloyl groups to react with (B) an aliphatic polyisocyanate at a molar ratio (OH/NCO) of 1.01-1.24. The objective activated energy beam-curable coating includes the resultant resin composition for coating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a novel and useful active energy ray-curing method which, when used for coating plastic molded products and plastic films, provides a coating film having excellent abrasion resistance, adhesion and surface hardness. The present invention relates to a resin composition for a mold paint and an active energy ray-curable paint.

[0002]

2. Description of the Related Art In recent years, plastic materials such as engineering plastics are lightweight, and have excellent moldability and toughness.
It is used as a base material in general industry and daily necessities. However, plastics are inferior in surface hardness and abrasion resistance, so that the surface of the base material is often coated with a surface protective layer.

An energy ray-curing type coating agent which is cured by irradiation with ultraviolet rays, electron beams, etc.
Plastic surface protective layers have been put to practical use with added value such as energy saving, workability improvement, and productivity improvement.However, depending on the type of plastic base material, adhesion to the base material, surface hardness, There are many cases where it is difficult to balance with wear resistance.

[0004] When the number of functional groups of the polyfunctional acrylate compound is increased or the content of the compound is increased in order to satisfy the abrasion resistance, the cured film shrinks during the polymerization reaction at the time of irradiation with energy rays, so that the coating film may be damaged. Cracks may occur,
Due to distortion at the interface between the base material and the coating film, the coating film tended to peel or warp.

Therefore, urethane acrylates having excellent abrasion resistance, relatively hardly causing cracks in the coating film, and having a high degree of freedom in designing have been widely studied as polyfunctional acrylate compounds. This is attributable to the toughness of urethane bonds possessed by urethane acrylate. For example, JP
No. 0-37728 discloses a hydroxyl-containing polyfunctional (meth) compound.
A method for producing a polyfunctional urethane acrylate comprising an acrylate compound and an isocyanate compound is disclosed, wherein a molar ratio (OH / NCO) between a hydroxyl group (OH) and an isocyanate group (NCO) is 1.25 to 5.0. It is described that it is preferable to use it. This suggests that it is possible to shorten the reaction time by performing the urethanization reaction under the condition that the hydroxyl group is in a large excess, and the unreacted remaining hydroxyl group without reacting with the isocyanate compound. No consideration is given to a decrease in abrasion resistance that the contained polyfunctional (meth) acrylate compound exerts on the coating properties such as abrasion resistance. The gist of the publication is further clarified by looking at the molar ratio (OH / NCO) in the examples. In Examples, the molar ratio (OH / NCO) is 0.45 to 7.1.
Although synthesis examples in the range of 0 are described, most of them have a molar ratio (OH / NCO) of 2.4 or more and are produced by reacting hydroxyl groups with isocyanate groups under a large excess condition. The main point is to shorten the time.

A report on a polyfunctional urethane acrylate comprising a hydroxyl group-containing polyfunctional (meth) acrylate compound and an isocyanate compound is disclosed in JP-A-48-805.
No. 17 and JP-A-48-57620.

JP-A-48-80517 describes a radiation-curable resin composition containing a free isocyanate group, and the synthesis of a urethane acrylate comprising a polyfunctional (meth) acrylate compound containing a hydroxyl group and an isocyanate compound. Although an example is described, it is stated that containing a free isocyanate group improves adhesion to a metal material. Therefore, the addition of an isocyanate compound to include a polyisocyanate compound as a composition also improves the adhesion to metal materials. However, free isocyanate groups react with moisture in the air, so that not only storage stability is insufficient,
The pot life is short and the use is complicated.
In addition, in diluting a paint having a viscosity suitable for work with a solvent, an alcohol-based solvent having active hydrogen cannot be used because it reacts with a free isocyanate group. Furthermore, in the urethane (meth) acrylate described in the examples, the number of (meth) acryloyl groups contained in one molecule is two or less, and it is not intended to form a coating film having a high crosslinking density.

[0008] JP-A-48-57620 reports a urethane (meth) acrylate comprising a hydroxyl group-containing polyfunctional (meth) acrylate compound and a diisocyanate compound, and has a molar ratio (OH / NCO) of 1.0. The preferred range is 10 or less. This publication is intended mainly for application as a photosensitive resin for forming a corrosion-resistant film for plating or etching in the field of printed wiring, and the urethane (meth) acrylate described in Examples is also one molecule. Inside (meta)
Only a system containing two acryloyl groups is described, and is not intended to produce a coating film having a high crosslinking density.

[0009]

The problem to be solved by the present invention is to provide a resin composition for an active energy ray-curable paint capable of obtaining a coating film having excellent abrasion resistance, surface hardness and adhesion to plastics. It is to provide an active energy ray-curable paint.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies while aiming at the above-mentioned problems, and as a result, have found that a (meth) having a hydroxyl group and two or more (meth) acryloyl groups has been obtained. The acrylate compound (A) and the aliphatic polyisocyanate compound (B) have a hydroxyl group / isocyanate group molar ratio (OH / NCO) of 1.01 to 1.2.
And a resin composition for an active energy ray-curable coating material containing, as an essential component, a urethane (meth) acrylate compound (I) having an average of 5 or more (meth) acryloyl groups obtained by reacting in the range of 4 The active energy ray-curable coating composition containing the composition has good storage stability, and has been found to provide an effect coating film having excellent abrasion resistance, surface hardness, and excellent adhesion to plastics. I came to.

That is, the present invention relates to a method for converting a (meth) acrylate compound (A) having a hydroxyl group and two or more (meth) acryloyl groups and an aliphatic polyisocyanate compound (B) into a hydroxyl / isocyanate group. Molar ratio (OH
/ NCO) as an essential component, comprising a urethane (meth) acrylate compound (I) having an average of 5 or more (meth) acryloyl groups obtained by reacting in a range of 1.01 to 1.24. An active energy ray-curable coating composition comprising the active energy ray-curable coating composition and a resin composition for the active energy ray-curable coating composition.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The (meth) acrylate compound (A) used in the present invention is not particularly limited as long as it is a (meth) acrylate having a hydroxyl group and two or more (meth) acryloyl groups. For example, trimethylolpropanedi (meth) acrylate, ethoxylated trimethylolpropanedi (meth) acrylate, propoxylated trimethylolpropanedi (meth) acrylate,
Tri (2-hydroxyethyl isocyanurate) di (meth) acrylate, di (meth) acrylate of trihydric alcohol such as glycerin di (meth) acrylate, and di (meth) acrylate obtained by modifying the hydroxyl group of these di (meth) acrylates with ε-caprolactone (Meth) acrylate; pentaerythritol di (meth) acrylate, dipentaerythritol di (meth) acrylate, ditrimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, ditrimethylolpropane Tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, ditrimethylolpropanetetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate , Ditrimethylolpropanehexa (meth) acrylate and the like, which are polyfunctional (meth) acrylates of tetrahydric or higher alcohols having a hydroxyl group, and those polyfunctional (meth) acrylates having a hydroxyl group are partially alkylated. And polyfunctional (meth) acrylates having a hydroxyl group modified with a group or ε-caprolactone.

Among the above (meth) acrylate compounds (A), one hydroxyl group and three (meth) acryloyl groups are low in viscosity and excellent in curability due to having many (meth) acryloyl groups. Having a group (meta)
Acrylate compounds are preferred. Among them, pentaerythritol triacrylate and pentaerythritol trimethacrylate are preferred, but pentaerythritol triacrylate is particularly preferred from the viewpoint of excellent reactivity upon irradiation with active energy rays.

The aliphatic polyisocyanate compound (B) used in the present invention is a compound containing two or more aliphatic isocyanate groups in one molecule, for example, an aliphatic diisocyanate compound and an aliphatic diisocyanate compound. Adduct-type polyisocyanate compound synthesized from diisocyanate compound and polyfunctional polyol compound, aliphatic diisocyanate
And isocyanurate-type polyisocyanate compounds comprising a trimer of a compound. These aliphatic polyisocyanate compounds may be used alone or in a mixture, but among them, aliphatic diisocyanate compounds are preferable because they improve the abrasion resistance of the coating film.

The term "aliphatic isocyanate group" as used herein means an isocyanate group bonded to a carbon atom of a chain hydrocarbon, an isocyanate group desired to bond to a carbon atom of a cyclic saturated hydrocarbon, or a chain chain bonded to an aromatic ring. An isocyanate group bonded to a carbon atom of a hydrocarbon is referred to as an aliphatic diisocyanate compound. A diisocyanate compound containing two of these aliphatic isocyanate groups is referred to as an aliphatic polyisocyanate compound. The polyisocyanate compound containing at least one polyisocyanate means each.

Examples of the aliphatic diisocyanate compound include 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate,
Hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, 1,3-diisocyanate cyclohexane,
1,4-diisocyanatocyclohexane, dicyclohexylmethane-4,4'-diisocyanate, 1,3-
Tetramethylxylene diisocyanate, 1,4-tetramethylxylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 2,2,4-trimethylcyclohexane diisocyanate, 2,4,4-trimethylcyclohexane diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, norbornane diisocyanate, etc., among which 1,6-hexamethylene diisocyanate, dicyclohexylmethane-4,4 ' Diisocyanates are particularly preferred.

The urethane (meth) acrylate compound (I), which is an essential component of the active energy ray-curable coating resin composition of the present invention, is a (meth) acrylate compound (A)
And the aliphatic polyisocyanate compound (B), the molar ratio (OH / NCO) of the hydroxyl group contained in the (meth) acrylate compound (A) to the isocyanate group contained in the aliphatic polyisocyanate compound (B) is 1 .01-1.
It is a urethane (meth) acrylate compound having an average of 5 or more (meth) acryloyl groups obtained by reacting in the range of 24, and in particular, a molar ratio (OH / NCO)
Is within the range of 1.03 to 1.10, the time required for the isocyanate group to disappear during the urethanization reaction is short, the storage stability is good, and the cured coating is excellent in abrasion resistance. This is preferable in that a film can be obtained.

When the molar ratio (OH / NCO) is less than 1.01, the molar ratio (OH / NCO) is preferably 1.00.
If the molar ratio (OH / NCO) is other than about 1.00, it is not preferable because a large amount of time is required until the isocyanate group disappears during the urethanization reaction. Are not preferable since they remain in the system and cause a decrease in storage stability.

The molar ratio (OH / NCO) is 1.24.
If the amount is larger than the above range, a large amount of unreacted (meth) acrylate compound (A) which does not participate in the urethanization reaction remains, which is not preferable because the abrasion resistance of the coating film is reduced.

As described above, it is essential that the urethane (meth) acrylate compound (I) used in the present invention has at least 5 (meth) acryloyl groups on average, and is particularly excellent in abrasion resistance. Those having an average of 5 to 8 are preferred from the viewpoint of obtaining a cured coating film. If the number of (meth) acryloyl groups is less than 5 on average, the resulting coating film has an insufficient cross-linking density, so that the abrasion resistance of the coating film is insufficient.

The urethane (meth) acrylate compound (I) is, for example, a (meth) acrylate compound (A)
And the aliphatic polyisocyanate compound (B) under the usual reaction conditions for urethanization reaction, that is, 20 to 100.
C, preferably at 40 to 80C. Although the reaction can be carried out under a nitrogen atmosphere, it is preferable to carry out the reaction in a dry air atmosphere containing oxygen so that the (meth) acryloyl group does not cause polymerization.

In the urethanization reaction, a normal organic tin catalyst represented by dibutyltin diacetate or dibutyltin dilaurate, or a tertiary amine compound such as triethylamine may be used to accelerate the reaction. .
Further, in order to prevent polymerization of the (meth) acryloyl group from occurring during the reaction, a polymerization inhibitor such as methoquinone and hydroquinone or an antioxidant may be used.

In the urethanization reaction, an organic solvent having no active hydrogen group that reacts with an isocyanate group can be used alone or in combination of two or more. Specific examples include ester solvents such as ethyl acetate and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; and aromatic solvents such as toluene and xylene.

The urethane (meth) contained as an essential component in the active energy ray-curable coating resin composition of the present invention.
A radical polymerizable monomer (II) other than the acrylate compound (I) and / or an organic solvent (III) may be contained.

Examples of the radical polymerizable monomer (II) include butanediol di (meth) acrylate,
Hexanediol di (meth) acrylate, ethoxylated hexanediol di (meth) acrylate, propoxylated hexanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate Di (meth) acrylates such as, neopentyl glycol di (meth) acrylate, ethoxylated neopentyl glycol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate;

2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2
-Hydroxybutyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, glycidyl (meth) acrylate, acryloylmorpholine, N-vinylpyrrolidone, tetrahydrofurfuryl acrylate , Cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth)
Acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, 2
-Ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phosphoric acid (meth) acrylate, ethylene oxide modified phosphoric acid (meth) acrylate, phenoxy (meth) acrylate, ethylene oxide Modified phenoxy (meth) acrylate, propylene oxide-modified phenoxy (meth) acrylate, nonylphenol (meth) acrylate, ethylene oxide-modified nonylphenol (meth) acrylate, propylene oxide-modified nonylphenol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxypolyethylene Glycol (meth) acrylate, methoxypropylene glycol (meth) acrylate, 2
-(Meth) acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- (meth) acryloyloxyethyl hydrogen phthalate, 2- (meth) acryloyloxypropyl hydrogen phthalate, 2 -(Meth) acryloyloxypropyl hexahydrohydrogen phthalate, 2- (meth) acryloyloxypropyl tetrahydrohydrogen phthalate, dimethylaminoethyl (meth) acrylate, trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoro Propyl (meth) acrylate, octafluoropropyl (meth) acrylate, octafluoropropyl (meth) acrylate, adaman Mono (meth) acrylates such as mono (meth) acrylate;

Trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, tris-2-hydroxyethyl isocyanurate tri (meth) acrylate, glycerin tri ( Tri (meth) acrylates such as (meth) acrylate;

Pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra 4- or more-functional poly (meth) such as (meth) acrylate, dipentaerythritol penta (meth) acrylate, ditrimethylolpropanepenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and ditrimethylolpropanehexa (meth) acrylate ) Acrylates;

And polyfunctional (meth) acrylates in which a part of the above (meth) acrylate is substituted with an alkyl group or ε-caprolactone.

These radically polymerizable monomers (II) may be used alone or in combination of two or more. The amount of the radically polymerizable monomer (II) is used in order to prevent a decrease in the abrasion resistance of the resulting coating film. It is preferably 100 parts by weight or less, more preferably 10 to 70 parts by weight, based on 100 parts by weight of the urethane (meth) acrylate compound (I).

The resin composition for an active energy ray-curable coating material of the present invention may further contain other urethane acrylate resin, epoxy acrylate resin, vinyl urethane resin, vinyl ester resin, unsaturated polyester resin depending on the target performance. There is no problem even when various energy ray-curable resins such as a resin containing an unsaturated double bond are used together.

The active energy ray-curable coating resin composition of the present invention may further comprise an organic solvent (III) for adjusting the viscosity.
Can be used. When the organic solvent (III) is used, it is preferable to remove the organic solvent (III) by a hot air drier after coating, and the use amount is not particularly limited, but usually the solid content concentration of the paint is 5 to 40% by weight. %.

As the organic solvent (III), those having a boiling point of 50 to 180 ° C. are usually used to obtain an active energy ray-curable coating resin composition which is excellent in workability at the time of coating and drying before and after curing. Alcoholic solvents such as methanol, isopropyl alcohol, n-butanol and isobutanol; methyl acetate, ethyl acetate, butyl acetate, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether Ester solvents such as acetate; acetone, methyl ethyl ketone,
Ketone solvents such as methyl isobutyl ketone; toluene,
Examples thereof include aromatic solvents such as xylene, and mixtures thereof.

The photopolymerization initiator (IV) can be added to the active energy ray-curable coating resin composition of the present invention according to the purpose. As the photopolymerization initiator (IV), various ones can be used. Among them, particularly typical ones are those which generate radicals by hydrogen abstraction of benzophenone, benzyl, Michler's ketone, thioxanthone, anthraquinone and the like. And the like. These compounds are generally used in combination with tertiary amines such as methylamine, diethanolamine, N-methyldiethanolamine, and tributylamine.

As another type of photopolymerization initiator, for example, a compound of a type that generates a radical by intramolecular splitting can be mentioned. Specifically, for example, benzoin,
Dialkoxyacetophenone, acyl oxime ester, benzyl ketal, hydroxyalkylphenone,
Halogenoketone and the like.

If necessary, a polymerization inhibitor such as hydroquinone, benzoquinone, tolhydrinoquinone and paratertiary butyl catechol may be added in combination with the photopolymerization initiator (IV).

The active-energy-ray-curable coating resin composition of the present invention may further contain an active-energy-ray-curable paint by using a pigment, a natural or synthetic polymer, or other compounding agents, if necessary. It can be a paint.

The above-mentioned pigments are not particularly restricted but include, for example, extender pigments, white pigments, black pigments, gray pigments, red pigments described in the 1970 Handbook of Coating Materials (edited by the Japan Paint Manufacturers Association). Organic pigments and inorganic pigments such as brown pigments, green pigments, blue pigments, purple pigments, metal powder pigments, luminescent pigments, pearlescent pigments, and plastic pigments. Various examples of these colorants are listed, and examples of organic pigments include various insoluble azo pigments such as Benzidine Yellow, Hansa Yellow, Lake 4R and the like; Lake C, Carmine 6B, Bordeaux 10 and the like. Soluble azo pigments; phthalocyanine blue, phthalocyanine green, etc., various (copper) phthalocyanine pigments; rhodamine lake, methyl violet lake, etc., various chlorine dyeing lakes; quinoline lake, fast sky blue, etc. Various mordant dye pigments; various vat dye pigments such as anthraquinone pigments, thioindigo pigments, and perinone pigments;
Examples include various quinacridone pigments such as Synchasia Red B; various oxazine pigments such as oxazine violet; various condensed azo pigments such as chromophtal; and aniline black.

Examples of the inorganic pigments include various chromates such as graphite, zinc chromate and molybdate orange; various ferrocyanide compounds such as navy blue;
Various metal oxides such as titanium oxide, zinc oxide, mapico yellow, iron oxide, red iron oxide, chrome green, etc .; various sulfides or selenides such as cadmium yellow, cadmium red, mercury sulfide, etc .; barium sulfate, sulfuric acid Various sulfates such as lead; various silicates such as calcium silicate and ultramarine blue; calcium carbonate;
Various carbonates such as magnesium carbonate; various phosphates such as cobalt violet and manganese purple; various metal powder pigments such as aluminum powder, gold powder, silver powder, copper powder, bronze powder and brass powder; Metallic pigments and pearl pigments, such as metal flake pigments, mica flake pigments, mica flake pigments coated with metal oxides, mica-like iron oxide pigments, and the like; graphite, carbon black, and the like.

Examples of extenders include precipitated barium sulfate, powder, precipitated calcium carbonate, calcium bicarbonate, dolomite, alumina white, silica, hydrated fine silica powder (white carbon), ultrafine powder anhydrous silica (Aerosil),
Examples include silica sand, talc, precipitated magnesium carbonate, bentonite, clay, kaolin, loess and the like.

Further, a plastic pigment [for example, Grandol PP-100 manufactured by Dainippon Ink and Chemicals, Inc.]
0, PP-2000S].

The proportion of the pigment used depends on the type of the pigment, the desired hue, the type of the photopolymerization initiator to be used, and the like, and is not particularly limited. However, when the composition is cured by ultraviolet light, the colored pigment is necessary for curing. Since a large amount of ultraviolet light is absorbed, a range in which sufficient ultraviolet light for curing can be supplied to the unsaturated double bond produced by radical polymerization is preferable. Usually, the pigment is 30 parts by weight or less based on 100 parts by weight of the resin solid content. Is preferable.

Examples of natural or synthetic high-molecular substances include other various vinyl ester resins, polyisocyanate compounds, polyepoxides, acrylic resins, alkyd resins, urea resins, melamine resins, polyvinyl acetate. , Vinyl acetate copolymers, polybutadiene elastomers, saturated polyesters, saturated polyethers, nitrocellulose or cellulose derivatives such as cellulose acetate butyrate; linseed oil, tung oil,
Fats and oils such as soybean oil, castor oil and epoxidized oils and the like can be mentioned.

Other compounding agents include antioxidants, ultraviolet absorbers, leveling agents, surfactants, slip agents,
An antifoaming agent and the like are included.

The active energy ray-curable coating composition of the present invention as described above is adjusted to an appropriate coating viscosity with an organic solvent or the like, if necessary, coated on a plastic substrate or the like, and exposed to ultraviolet light, visible light, laser light, or the like. Light, electron beam, X-ray, γ
Irradiation with energy rays such as radiation, plasma, microwave, etc. can be cured to form a coating film.

The plastic substrate means a plastic molded product or a plastic film. Examples of the plastic molded product include ABS resin, polymethyl methacrylate resin, polycarbonate resin, polypropylene resin,
Examples include molded products produced from an unsaturated polyester resin and a polymer alloy resin thereof by injection molding, extrusion molding, press molding, or the like. Examples of the plastic film include films made of polyethylene, polypropylene, triacetyl cellulose, polyethylene terephthalate, vinyl chloride, polycarbonate, and the like. The active energy ray-curable coating material of the present invention may be applied directly to these plastic substrates. However, if the plastic substrate is to be designed, the base material is applied to the plastic substrate after applying the base coat agent. The active energy ray-curable paint of the invention may be applied as a top coat. Further, in order to modify the surface of the plastic film, surface oxidation such as corona discharge or chromic acid treatment may be performed, or the surface may be made uneven by sandblasting or solvent treatment. Furthermore, after applying a solution-type or emulsion-type coating agent to the plastic film to impart properties such as heat sealability, moisture proofness, and adhesion of the paint, the active energy ray-curable paint of the present invention is topped. It may be painted as a coat.

Examples of the base coat agent for the plastic substrate include a paint containing an acrylic resin and a pigment. The base coat agent is not particularly limited to the composition of the acrylic resin. A top coat using an acrylic resin obtained by copolymerizing a monomer mixture containing (meth) acrylate and methyl (meth) acrylate as essential components is composed of a base coat and the active energy ray-curable paint of the present invention. It is preferable to improve the interlayer adhesion between the substrate and the substrate.

As the pigment, those exemplified for the active energy ray-curable paint may be used. As the monomer mixture used for obtaining the acrylic resin, for example, it is preferable that n-butyl (meth) acrylate and methyl (meth) acrylate are essential components.
Copolymerizable monomers other than butyl (meth) acrylate and methyl (meth) acrylate can be used in combination.

Representative copolymerizable monomers other than n-butyl (meth) acrylate and methyl (meth) acrylate include (meth) acrylic acid, ethyl (meth) acrylate, and isopropyl (meth) acrylate. , 2-ethylhexyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, n-hexyl (meth) acrylate, lauryl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, stearyl (Meth) acrylate, maleic acid, itaconic acid, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, styrene, (meth) acrylamide, N-methylol (meth) acrylamide,
Diacetone (meth) acrylamide, glycidyl (meth) acrylate, vinyltoluene, vinyl acetate, vinyl chloride, (meth) acrylonitrile and the like,
The present invention is not limited to these, and any monomer used in ordinary acrylic resins can be used.

[0050]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. In the following, all parts and percentages are by weight unless otherwise specified. The NCO% (isocyanate content) is a numerical value representing the content of isocyanate groups contained in the sample on a weight basis.

Synthesis Example 1 [Preparation of urethane (meth) acrylate compound (A)] Aronix M-305 was placed in a 1-liter flask equipped with a stirrer, a gas inlet tube, a condenser and a thermometer.
[Pentaerythritol triacrylate / pentaerythritol tetraacrylate manufactured by Toa Gosei Co., Ltd. = 60
/ 40 (weight ratio) mixture, hydroxyl value 116 mgKOH /
g] 549.1 parts, dibutyltin diacetate 0.1 part,
Sumilizer BHT [Antioxidant manufactured by Sumitomo Chemical Co., Ltd.]
0.6 part, 0.1 part of methoquinone (a polymerization inhibitor manufactured by Seiko Chemical Industry Co., Ltd.) and 160.0 parts of butyl acetate were added, and the temperature was gradually raised while uniformly mixing. When the temperature reaches 60 ° C, Desmodur H [Sumitomo Bayer Urethane
Hexamethylene diisocyanate, NCO% = 5
(0%), 90.9 parts were added, and reacted at 80 ° C. for 5 hours to obtain 800 parts of urethane acrylate (I-1).
Table 1 shows the nonvolatile content, the appearance, the Gardner viscosity (25 ° C.), the Gardner color, the isocyanate content, and the molar ratio (OH / NCO) in the urethane reaction of the obtained urethane acrylate (A1).

Synthesis Examples 2 to 5 (same as above) The reaction was carried out in the same manner as in Synthesis Example 1 except that the raw material components were used in the composition ratios shown in Table 1, and urethane acrylates (I-2) to (I- 6) 800 parts were obtained. The obtained urethane acrylate has a nonvolatile content, an appearance, a Gardner viscosity (25 ° C.), a Gardner color, an isocyanate content, and a molar ratio (OH / NC) in the urethane reaction.
O) is shown in Table 1.

[0053]

[Table 1]

<Footnotes to Table 1> Desmodur W: dicyclohexylmethane-4,4'-diisocyanate manufactured by Sumitomo Bayer Urethane Co., Ltd., NC
O% = 32.1% Takenate 500: Xylene diisocyanate manufactured by Takeda Pharmaceutical Co., Ltd., NCO% = 44.7% Takenate 600: Hydrogenated xylene diisocyanate manufactured by Takeda Pharmaceutical Co., Ltd., NCO% = 43.3% VESTANAT IPDI: Daicel Huls Co., Ltd., isophorone diisocyanate, NCO% = 37.8% Sumidur N-3300: Sumitomo Bayer Urethane Co., Ltd.
Isocyanurate type polyisocyanate, NCO% =
21.8%

Comparative Synthetic Examples 1 to 4 (Preparation of Comparative Urethane Acrylate) The reaction was carried out in the same manner as in Synthetic Example 1 except that each raw material component was used in the composition ratio shown in Table 2. 800 parts of acrylates (I-1 ') to (I-4') were obtained. Table 2 shows the nonvolatile content, the appearance, the Gardner viscosity (25 ° C.), the Gardner color, the isocyanate content, and the molar ratio (OH / NCO) in the urethane reaction of the obtained urethane acrylate.

[0056]

[Table 2]

<Table 2 footnote> 2-hydroxyethyl acrylate: manufactured by Osaka Organic Chemical Industry Co., Ltd.

Examples 1 to 6 and Comparative Examples 1 to 4 Using the urethane acrylates (I-1 to I-6, I-1 'to I-4') obtained in the synthesis examples and the comparative synthesis examples,
As shown in Tables 3 and 4, butyl acetate was added to dilute the nonvolatile content to 40%, and then Irgacure # 184 [Ciba Specialty Chemicals Co., Ltd.]
Photoinitiator, 1-hydroxy-cyclohexyl-phenyl-ketone], respectively, and each of the active energy ray-curable coating resin compositions (X1 to X6, X1 'to X
4 ') was prepared.

[0059]

[Table 3]

[0060]

[Table 4]

Next, on SUMIPEC E (manufactured by Sumitomo Chemical Co., Ltd .: polymethyl methacrylate molded plate),
The obtained active energy ray-curable coating resin composition (X1 to X6, X1 'to X4') was dried at a dry film thickness of 1
After coating with a bar coater so as to be 0 μm,
Drying was performed at 70 ° C. for 10 minutes using a hot air drier to remove the organic solvent by volatilization. Next, using an ultraviolet irradiation device, a high-pressure mercury lamp of 80 W / cm was used at a speed of 5 m / min.
The film was passed twice to form a cured coating film, and the obtained cured coating film was evaluated by the following method. The evaluation results are shown in Tables 5 and 6.

<Evaluation method> (1) Primary adhesion: 1 mm × 1 on the coated surface with a cutter knife
After 100 grids of 100 mm were created and a cellophane tape manufactured by Nichiban Co., Ltd. was applied, the cells were peeled off. At this time, the number of grids in which the coating film adhered without peeling was counted and evaluated. (2) Pencil hardness: A scratch test was carried out with a 1 kg load using a Mitsubishi Pencil Uni, and the hardness one rank below the lowest hardness at which scratches were made was indicated. (3) Abrasion resistance: 4 using steel wool # 0000
After performing a 500 reciprocating wear test under a load of 40 g / cm ² ,
外 観 indicates that the coating film had no scratches, Δ indicates that the scratches occurred slightly, and x indicates that the coating film was whitened due to deep scratches.

[0063]

[Table 5]

[0064]

[Table 6]

[0065]

The resin composition for an active energy ray-curable coating composition and the active energy ray-curable coating composition of the present invention have good storage stability and are excellent in abrasion resistance, surface hardness and adhesion to plastics. Is obtained.

Claims (10)

[Claims] 1. A (meth) acrylate compound (A) having a hydroxyl group and two or more (meth) acryloyl groups,
The aliphatic polyisocyanate compound (B) has a hydroxyl group / isocyanate group molar ratio (OH / NCO) of 1.0
(Meta) obtained by reacting in the range of 1-1.24
Urethane (meta) having an average of 5 or more acryloyl groups
A resin composition for an active energy ray-curable coating material, comprising an acrylate compound (I) as an essential component. 2. The urethane (meth) acrylate compound (I) is obtained by converting the (meth) acrylate compound (A) and the aliphatic polyisocyanate compound (B) into a hydroxyl group / isocyanate group molar ratio (OH / NCO). Is 1.03 ~
The energy ray-curable resin composition according to claim 1, which is a urethane (meth) acrylate compound having an average of 5 to 8 (meth) acryloyl groups obtained by reacting within a range of 1.10. 3. The method according to claim 1, wherein the (meth) acrylate compound (A) is
The resin composition for an active energy ray-curable coating according to claim 1 or 2, which is a (meth) acrylate compound having one hydroxyl group and three (meth) acryloyl groups. 4. The method according to claim 1, wherein the (meth) acrylate compound (A) is
The resin composition for an active energy ray-curable coating according to claim 1 or 2, which is pentaerythritol tri (meth) acrylate. 5. The resin composition for an active energy ray-curable coating material according to claim 1, wherein the aliphatic polyisocyanate compound (B) is an aliphatic diisocyanate compound. 6. The method of claim 1, wherein the aliphatic polyisocyanate compound (B) is hexamethylene diisocyanate (HDI)
And / or dicyclohexylmethane-4,4'-diisocyanate (H12MDI).
The resin composition for an active energy ray-curable coating material according to any one of the above. 7. A radical polymerizable monomer (II) other than the urethane (meth) acrylate compound (I) and / or
Or the resin composition for an active energy ray-curable coating material according to any one of claims 1 to 6, which contains an organic solvent (III). 8. The resin composition for an active energy ray-curable coating material according to claim 1, further comprising a photopolymerization initiator (IV). 9. The active energy ray-curable coating resin composition according to claim 1, which is a coating resin composition for a plastic molded article or plastic film. 10. An active energy ray-curable paint comprising the resin composition for an active energy ray-curable paint according to any one of claims 1 to 9.