JPH09268260A - Active energy ray-curable coating material for plastic and plastic molded product whose surface is treated with the coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an active energy ray-curable coating material for plastics, excellent in abrasion resistance and in adhesivity to various kinds of plastic substrates including acrylic resins, polyester resins and polyolefin resins and capable of imparting also antistaticity. SOLUTION: This coating material comprises 30-90wt.% of a (meth)acryloyl group-containing compound having an additivity-average acryl equivalent of 80-300 and not containing a quaternary ammonium salt group, 10-70wt.% of N-vinylformamide and 0-25wt.% of a (meth)acryloyl group-containing compound having a quaternary ammonium salt group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating agent for active energy ray-curable plastics and a plastic molded article obtained by surface treatment with the coating agent. In particular, the coating agent of the present invention is an acrylic resin,
It is useful as a hard coating agent for plastic substrates such as polyester resins and polyolefin resins.

[0002]

2. Description of the Related Art Today, various plastics are used in a wide range of fields because of their excellent characteristics such as easy workability, light weight and transparency. However, these plastics generally have the drawbacks of having a soft surface, being easily scratched, and being easily charged. In order to make up for such drawbacks, various kinds of coatings are applied to the surface of plastics. In particular, active energy ray-curable coating agents are evaluated for their hard coat properties, chemical resistance, finished appearance, energy saving and high productivity.

However, conventionally known active energy ray-curable coating agents composed of (meth) acryloyl group-containing compounds are generally not suitable for plastic substrates such as polyvinyl chloride resin, polycarbonate resin and ABS resin. Although it adheres well, it does not adhere sufficiently to a plastic substrate such as an acrylic resin, a polyester resin or a polyolefin resin. Therefore, when coating or printing a plastic substrate such as an acrylic resin, a polyester resin, or a polyolefin resin with an active energy ray-curable coating agent, the plastic substrate is first subjected to corona treatment or frame treatment, or an anchor. The coating has to be applied and a very complicated process is required.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned drawbacks of the conventional active energy ray-curable plastic coating agents. That is, the present invention provides a coating agent for an active energy ray-curable plastic, which has excellent adhesion and scratch resistance to various plastic substrates including acrylic resin, polyester resin, polyolefin resin and the like, and which can also impart antistatic property. The purpose is to provide.

[0005]

[Means for Solving the Problems] As a result of intensive research conducted by the present inventors in order to solve the above problems, as a result, the acrylic equivalent, which has been conventionally used as a coating agent for active energy ray-curing plastics, is 80 to N-vinylformamide having a (meth) acryloyl group-containing compound of 300 has a surface tension close to that of a plastic substrate such as an acrylic resin, a polyester resin, or a polyolefin resin, and has excellent penetrability with the plastic substrate. The active energy ray-curable composition, which is used in combination with a certain amount or more, has adhesion and scratch resistance to various plastic substrates,
Fast curing, excellent flexibility, and when used together with a (meth) acryloyl group-containing compound having a quaternary ammonium salt, antistatic property and antifogging property can be imparted, and the cured product is less colored, It has been found that a coating agent for active energy ray-curable plastic can be provided.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a (meth) acryloyl group-containing compound having a quaternary ammonium salt having a weighted average of acrylic equivalent of 80 to 300 is used. Here, the acrylic equivalent is the mass of the resin containing 1 gram equivalent of the (meth) acryloyl group, that is, a numerical value expressed in units of g / eq. The (meth) acryloyl group means an acryloyl group and / or a methacryloyl group, and the following (meth) has the same meaning.

As the (meth) acryloyl group-containing compound having no quaternary ammonium salt having an acrylic equivalent of 80 to 300, a compound having two or more (meth) acryloyl groups is preferable. Examples of such a compound having two or more (meth) acryloyl groups include trimethylolpropane tri (meth) acrylate, trimethylolpropane poly (repeating number 1 to 3) propoxytri (meth) acrylate, trimethylolpropane poly (repeating). 1 to 3) ethoxy (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol poly (repeating number 1 to 4) propoxytetra (meth) acrylate, pentaerythritol poly (repeating number) 1-4) ethoxytetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) ) Acrylate, dipentaerythritol poly (repetition number 1
6) Propoxyhexa (meth) acrylate, dipentaerythritol poly (repeating number 1 to 6) ethoxyhexa (meth) acrylate, bisphenol A poly (repeating number 1 to 4) propoxydi (meth) acrylate, bisphenol A poly (repeating number 1) 4) Ethoxydi (meth) acrylate, polyurethane polyacrylate, polyester polyacrylate, epoxy polyacrylate and the like can be mentioned, but the invention is not limited thereto. Such acrylic equivalent is 80 to 3
The (meth) acryloyl group-containing compound having no quaternary ammonium salt of 00 can be appropriately used alone or as a mixture of two or more compounds.

As the (meth) acryloyl group-containing compound having no quaternary ammonium salt, tetrahydrofurfuryl (meth) acrylate, carbitol (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, morpholine. It is also possible to use a compound having one (meth) acryloyl group such as (meth) acrylamide, phenoxyethyl (meth) acrylate, and isobornyl (meth) acrylate. In addition, it does not have a quaternary ammonium salt used in the present invention (meth)
The acryloyl group-containing compound may have a weighted average of acrylic equivalents of 80 to 300, and those having an acrylic equivalent of more than 300 may be used in combination. When the additive average of the acrylic equivalent is less than 80, the crosslink density is high, the coating surface becomes brittle, and the curing shrinkage is large and the adhesion is insufficient. On the other hand, when the additive average of the acrylic equivalent exceeds 300, curing occurs. The property is insufficient, and in any case, it is not preferable.

The coating agent for active energy ray-curable plastics of the present invention comprises 30 to 90% by weight of a (meth) acryloyl group-containing compound having a quaternary ammonium salt having an acrylic equivalent weight average of 80 to 300. Preferably 50-90% by weight and N-vinylformamide 10-70% by weight, preferably 10-50% by weight
Comprising. The ratio of N-vinylformamide is 10
If it is less than 10% by weight, it has poor penetrability into a plastic substrate such as an acrylic resin, a polyester resin or a polyolefin resin, and the adhesiveness to the plastic substrate cannot be satisfied, and the N-vinylformamide has scratch resistance, rapid curing, Not flexible enough. On the other hand, when it exceeds 70% by weight, the proportion of the (meth) acryloyl group-containing compound becomes small, the crosslink density becomes small, and the scratch resistance cannot be satisfied.

In addition to the (meth) acryloyl group-containing compound and N-vinylformamide, the active energy ray-curable plastic coating agent of the present invention contains a quaternary ammonium compound in order to improve antistatic property and antifogging property. It is also possible to contain a (meth) acryloyl group-containing compound having a salt.

As the (meth) acryloyl group-containing compound having a quaternary ammonium salt, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl ( (Meth) acrylate, N, N-dipropylaminoethyl (meth) acrylate, N, N-dibutylaminoethyl (meth) acrylate, N, N-dihydroxyethylaminoethyl (meth) acrylate, N, N
-Dimethylaminoethyl (meth) acrylamide, N,
N-diethylaminoethyl (meth) acrylamide,
Examples thereof include those obtained by quaternizing a tertiary amino group of a (meth) acryloyl group-containing compound having a tertiary amino group such as N, N-dimethylaminopropyl (meth) acrylamide with a quaternizing agent. Specific examples of the quaternizing agent include:
Examples thereof include alkylsulfates such as dimethylsulfate, diethylsulfate and dipropylsulfate, sulfonates such as methyl p-toluenesulfonate and methylbenzenebenzenesulfonate, and alkyl halides such as alkyl chlorides, alkyl bromides and benzyl chlorides.

The amount of the (meth) acryloyl group-containing compound having a quaternary ammonium salt used is 0 to 25% by weight in the active energy ray-curable plastic coating agent. If it exceeds 25% by weight, the curability cannot be satisfied, which is not preferable.

Furthermore, when the coating agent for active energy ray-curable plastics of the present invention is cured by ultraviolet rays, it is necessary to contain a photopolymerization initiator. On the other hand, when curing with an electron beam or the like, a photopolymerization initiator is unnecessary. As the photopolymerization initiator, any known photopolymerization initiator may be used, but a photopolymerization initiator having good storage stability after being mixed with the coating agent is preferable. As such a photopolymerization initiator, Darocur 117
3, Irgacure 651, Irgacure 184, Irgacure 907 (manufactured by Ciba Geigy), benzophenone, o-benzoylbenzoic acid methyl ester, p-dimethylaminobenzoic acid ester, p-dimethylacetophenone, thioxanthone, alkylthioxanthone, amines, etc. Can be given. One of these photopolymerization initiators may be appropriately selected alone or used as a mixture of two or more compounds. When it is necessary to use the photopolymerization initiator, the usage ratio thereof is usually 0.1 to 10% by weight, preferably 1 to 5% by weight, based on the coating agent.

Further, the active energy ray-curable plastic coating material of the present invention may contain a solvent, a non-reactive resin and various additives depending on the application and the coating method. Considering the solubility and the drying rate, the solvent is preferably ethanol, isopropyl alcohol, methyl ethyl ketone, ethyl acetate, butyl acetate, toluene, xylene or the like. Moreover, as the non-reactive resin, polyester resin, alkyd resin, phenol resin, polyurethane, polybutadiene, polyether, epoxy resin, styrene-containing polymer and the like can be mentioned. Examples of the additives include silicon compounds, leveling agents, antioxidants, polymerization inhibitors, and the like.

The active energy ray-curable plastic coating agent of the present invention is applied to the surface of various plastic moldings by conventional means such as gravure coater, roller, spray, spin, flow coating, dipping, etc.
It is cured by irradiation with active energy rays such as ultraviolet rays and electron rays to form a cured film having excellent adhesion. Further, by forming a cured film on the surface of the plastic molded product, various properties such as scratch resistance, chemical resistance, antistatic property, antifogging property and transparency can be imparted to the plastic molded product. Examples of plastic molded products include various plastic molded products such as polyvinyl chloride resin, polycarbonate resin, ABS resin, acrylic resin, polyester resin and polyolefin resin. Specifically, polycarbonate, polystyrene, polymethylmethacrylate, a plastic lens made of styrene-methylmethacrylate copolymer or the like, polypropylene, polyethylene terephthalate, polystyrene,
Examples include molded products and sheet-shaped products of various shapes such as polymethylmethacrylate, polyamide, polymethylpentene or polyethersulfone.

[0016]

The active energy ray-curable plastic coating agent of the present invention has excellent adhesion to various plastic substrates, and can be applied to plastic moldings in terms of scratch resistance, chemical resistance, antistatic property, and antistatic property. It can be used as a hard coating agent for plastics that can impart various properties such as cloudiness and transparency. The active energy ray-curable plastic coating agent of the present invention has low viscosity and good coating workability.

[0017]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples. In each example, parts are based on weight.

Example 1 Dipentaerythritol polyacrylate (manufactured by Arakawa Chemical Industry Co., Ltd., beam set 700, acrylic equivalent 95)
80 parts, 20 parts of N-vinylformamide and 1-hydroxycyclohexyl phenyl ketone as a photopolymerization initiator (manufactured by Ciba Geigy Corp., Irgacure 184)
Hereinafter, 5 parts (hereinafter abbreviated as “Irg184”) were weighed in a beaker, stirred and heated under heating at 50 ° C., and dissolved to prepare an active energy ray-curable plastic coating agent.

Example 2 Pentaerythritol polyacrylate (manufactured by Arakawa Chemical Industry Co., Ltd., beam set 710, acrylic equivalent 88) 7
0 part, N-vinylformamide 20 parts, N, N-dimethylaminoethyl methacrylate 10 parts and "Irg
5 parts of "184" were weighed in a beaker, stirred and heated under heating at 50 ° C., and dissolved to prepare an active energy ray-curable plastic coating agent.

Example 3 Bisphenol A tetraethoxy acrylate (manufactured by Arakawa Chemical Industry Co., Ltd., beam set 300, acrylic equivalent 2)
62) 70 parts, 30 parts of N-vinylformamide and 5 parts of "Irg184" were weighed out in a beaker, stirred under heating at 50 ° C and dissolved to prepare an active energy ray-curable plastic coating agent.

Example 4 Polyurethane polyacrylate (Arakawa Chemical Industry Co., Ltd.)
Made, beam set 575, acrylic equivalent 189) 60
Parts, 40 parts of N-vinylformamide and “Irg18
4 parts and 5 parts were weighed out in a beaker, stirred and heated under heating at 50 ° C., and dissolved to prepare an active energy ray-curable plastic coating agent.

Comparative Example 1 Dipentaerythritol polyacrylate (manufactured by Arakawa Chemical Industry Co., Ltd., beam set 700, acrylic equivalent 95)
100 parts and 5 parts of "Irg184" were weighed out in a beaker, stirred and heated under heating at 50 ° C, and dissolved to prepare an active energy ray-curable plastic coating agent.

Comparative Example 2 Dipentaerythritol poly (penta or hexa) acrylate (manufactured by Arakawa Chemical Industry Co., Ltd., Beamset 70)
0, acrylic equivalent 95) 80 parts, morpholine acrylamide 20 parts and "Irg184" 5 parts were weighed in a beaker and stirred under heating at 50 ° C. to dissolve to prepare an active energy ray-curable plastic coating agent. .

(Preparation of Test Piece) The active energy ray-curable plastic coating material obtained in the above-mentioned Examples or Comparative Examples was applied onto a polypropylene resin with an applicator to a thickness of 10 μm, and a low-pressure mercury lamp ( 120
W / cm, one light, irradiation height 10 cm, belt speed 1
(20 m / min) and repeated until it became tack-free, and after the coating agent was cured, the following evaluation was performed. Table 1 shows the evaluation results.

(1) Curability The irradiation dose (mJ / cm ² ) required for curing when the above test piece was prepared was measured.

(2) Adhesion property The cured coating film portion of the above test piece was cross-cut and a cellophane tape peeling test was conducted, and the condition of the test piece was evaluated according to the following criteria. ◯: No peeling and no chipping Δ: Slight chipping ×: Complete peeling of cured composition coating, most peeling

(3) Scratch resistance The cured coating film portion of the test piece was lightly rubbed with steel wool, and the condition of the test piece was evaluated according to the following criteria. ○: No scratches △: Slight scratches are seen ×: Significant scratches are seen

[0028]

Claims (3)

[Claims] 1. The additive average of acrylic equivalent is 80 to 300.
30 to 90% by weight of a (meth) acryloyl group-containing compound having no quaternary ammonium salt, 10 to 70% by weight of N-vinylformamide, and 0 to 25% by weight of a (meth) acryloyl group-containing compound having a quaternary ammonium salt. A coating agent for active energy ray-curable plastics that contains. 2. The additive average of acrylic equivalent is 80 to 300.
The active energy ray-curable plastic coating composition according to claim 1, wherein the (meth) acryloyl group-containing compound having no quaternary ammonium salt is a compound having two or more (meth) acryloyl groups. 3. The surface of the molded plastic article according to claim 1.
A plastic molded product on which a cured film of the active energy ray-curable plastic coating agent is formed.