JPH08208832A - Active energy ray curing type composition for coating plastics - Google Patents

Abstract

PURPOSE: To obtain the subject composition, comprising a specific compound containing the oxetane ring and a cationic photopolymerization initiator, having a high curing rate, excellent in adhesion, scuff resistance and surface smoothness of a film and useful for hard coating of a plastics. CONSTITUTION: This composition comprises (A) a compound having 1-4 oxetane rings e.g. a compound of formula I [R<1> is H, a 1-6C (fluoro)alkyl, allyl, etc.; R<2> is a 1-6C alkyl, a 2-6C alkenyl, phenyl, etc.] or a compound of formula II [R<3> is a (branched) alkylene, a (branched) poly(alkyleneoxy), a bivalent unsaturated hydrocarbon group, etc.]} and (B) a cationic photopolymerization initiator (e.g. a diaryliodonium salt or a triarylsulfonium salt) and, as necessary, further (C) a compound containing epoxy group, (D) a compound containing vinyl ether group or (E) a compound containing (meth)acryloyl group and a photopolymerization free radical initiator.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an active energy ray-curable composition for coating plastics, which comprises a compound having an oxetane ring.
It is used in the field of use, especially in the field of plastic hard coat. In addition, in this specification, an acryloyl group or a methacryloyl group is represented as a (meth) acryloyl group.

[0002]

2. Description of the Related Art Plastic materials are used as alternative materials for metal materials, etc., by taking advantage of their toughness and workability.
Plastic materials used in various applications, however, often have soft and easily scratched surfaces, and in order to solve this problem, there are more methods than ever before to improve the hardness and scratch resistance of the plastic material surface. Proposed. A typical example thereof is coating of the surface of a plastic material with an active energy ray-curable composition that is cured by an active energy ray such as ultraviolet rays or electron rays. The features of this method are that it is possible to obtain a wide range of properties by selecting an oligomer as a curing component, the curing speed is fast, the pot life is long, and the solvent is essentially solvent-free. However, most of the active energy ray-curable compositions for coating conventional plastic materials use polyfunctional acrylates or unsaturated polyesters that cure by active energy ray-initiated radical polymerization, but these are generally coated. In the application of a thin plastic coating with a film thickness of around several μm, the effect of polymerization inhibition by oxygen during curing is large, and the curability of the composition, the scratch resistance of the resulting coating film, the surface smoothness, etc. tend to be impaired. There was

As an active energy ray curing technique other than the active energy ray initiated radical polymerization, an active energy ray initiated cationic polymerization technique has been put into practical use. In particular, the active energy ray-initiated cationic polymerization is not inhibited by oxygen, so there is no limitation that it must be carried out in an inert atmosphere, and it has the advantage that rapid and complete polymerization can be carried out in air. To date, active energy ray initiated cationic polymerization techniques have focused on the polymerization of two types of monomers: epoxy resins and vinyl ethers. Particularly, the photocurable epoxy resin has excellent adhesiveness, and the coating film has good heat resistance and chemical resistance. However, the conventional photocurable epoxy resin has a defect that the photopolymerization rate is relatively slow, and thus cannot be used in applications where rapid photocuring is required. Further, low molecular weight photocurable epoxy resins have been pointed out to have toxicity such as mutagenicity, and the danger thereof has been regarded as a problem. On the other hand, many photocurable vinyl ethers are volatile or have a strong odor, shrinkage during curing is recognized as compared with photocurable epoxy, and adhesiveness is often insufficient.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The inventors of the present invention solve these problems by using a plastic coating having excellent curability and having excellent adhesion, scratch resistance and surface smoothness. In order to find out the active energy ray-curable composition, the above-mentioned investigations were made.

[0005]

Means for Solving the Problems The present inventors have made various investigations to solve the above-mentioned problems as a composition comprising a cyclic ether having a specific structure as an active energy ray-curable composition for plastic coating. The present invention has been completed to find out that it is possible. That is, the first invention of the present invention is an active energy ray-curable composition for plastic coating, which comprises a compound having 1 to 4 oxetane rings and a photocationic polymerization initiator, and the second invention further comprises a compound having an epoxy group. An active energy ray-curable composition for plastic coating according to the first invention, which comprises the third invention, further comprising a compound having a vinyl ether group.
An active energy ray-curable composition for plastic coating of the invention, a fourth invention is a first invention further containing a compound having a (meth) acryloyl group and a photoradical polymerization initiator,
It is the active energy ray-curable composition for plastic coating of the second invention or the third invention. Hereinafter, the present invention will be described in detail.

Compound Having 1 to 4 Oxetane Rings The compound having an oxetane ring used in the present invention has 1 to 4 oxetane rings. When a compound having 5 or more oxetane rings is used, the cured film of the composition loses flexibility and may be cracked by bending. The compound having an oxetane ring used in the present invention is
Various compounds can be used as long as they are compounds having 1 to 4 oxetane rings. Examples of the compound having one oxetane ring include compounds represented by the following general formula (1).

[0007]

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In the formula (1), R ¹ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, a fluoroalkyl group having 1 to 6 carbon atoms, It is an allyl group, an aryl group, a furyl group or a thienyl group. R ² is an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, 1-
Alkenyl having 2 to 6 carbon atoms such as propenyl group, 2-propenyl group, 2-methyl-1-propenyl group, 2-methyl-2-propenyl group, 1-butenyl group, 2-butenyl group or 3-butenyl group. Group, phenyl group, benzyl group,
A group having an aromatic ring such as fluorobenzyl group, methoxybenzyl group or phenoxyethyl group, alkylcarbonyl group having 2 to 6 carbon atoms such as ethylcarbonyl group, propylcarbonyl group or butylcarbonyl group, ethoxycarbonyl group, propoxycarbonyl group Alternatively, it is an alkoxycarbonyl group having 2 to 6 carbon atoms such as butoxycarbonyl group, or an N-alkylcarbamoyl group having 2 to 6 carbon atoms such as ethylcarbamoyl group, propylcarbamoyl group, butylcarbamoyl group or pentylcarbamoyl group. .

Next, examples of the compound having two oxetane rings include compounds represented by the following general formula (2).

[0010]

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In the formula (2), R ¹ is the same group as in the general formula (1). R ³ is, for example, a linear or branched alkylene group such as ethylene group, propylene group or butylene group, poly (ethyleneoxy)
Group or a linear or branched poly (alkyleneoxy) group such as a poly (propyleneoxy) group, a propenylene group, a linear or branched unsaturated hydrocarbon group such as a methylpropenylene group or a butenylene group, a carbonyl group, An alkylene group containing a carbonyl group, an alkylene group containing a carboxyl group, an alkylene group containing a carbamoyl group, and the like.
R ³ is also a polyvalent group selected from the groups represented by the following formulas (3), (4) and (5).

[0012]

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In the formula (3), R ⁴ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, a methoxy group, an ethoxy group, a propoxy group or a butoxy group. An alkoxy group having 1 to 4 carbon atoms such as, a halogen atom such as a chlorine atom or a bromine atom,
It is a nitro group, a cyano group, a mercapto group, a lower alkylcarboxyl group, a carboxyl group, or a carbamoyl group.

[0014]

[Chemical 4]

In the formula (4), R ⁵ is an oxygen atom, a sulfur atom, a methylene group, NH, SO, SO ₂ , C (C
F ₃ ) ₂ or C (CH ₃ ) ₂ .

[0016]

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In the formula (5), R ⁶ is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, or an aryl group. n is 0 to 20
00 is an integer. R ⁷ is an alkyl group having 1 to 4 carbon atoms such as methyl group, ethyl group, propyl group or butyl group,
Or, it is an aryl group. R ⁷ is also a group selected from the groups represented by the following formula (6).

[0018]

[Chemical 6]

In the formula (6), R ⁸ is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group and a butyl group, or an aryl group. m is 0 to 100
Is an integer. Specific examples of the compound having two oxetane rings include compounds represented by the following formulas (7) and (8).

[0020]

[Chemical 7]

The compound represented by the formula (7) is a compound of the formula (2) in which R ¹ is an ethyl group and R ³ is a carboxyl group.

[0022]

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The compound represented by the formula (8) is the compound of the general formula (2), wherein R ¹ is an ethyl group and R ³ is a group represented by the formula (5).
^A compound in which ⁶ and R ⁷ are methyl groups and n is 1.

Of the compounds having two oxetane rings, preferred examples other than the above compounds include compounds represented by the following general formula (9). In the formula (9), R ¹ is the same group as in the general formula (1).

[0025]

[Chemical 9]

Examples of the compound having 3 to 4 oxetane rings include compounds represented by the following general formula (10).

[0027]

[Chemical 10]

In the formula (10), R ¹ is the same group as in the general formula (1). R ⁹ represents, for example, a group represented by the following formulas (11) to (13) having 1 to 1 carbon atoms.
And 12 branched alkylene groups, branched poly (alkyleneoxy) groups such as the group represented by the following formula (14), branched polysiloxy groups such as the group represented by the following formula (15), and the like. j is 3 or 4.

[0029]

[Chemical 11]

[In the formula (11), R ¹⁰ is a methyl group,
A lower alkyl group such as an ethyl group or a propyl group. ]

[0031]

[Chemical 12]

[0032]

[Chemical 13]

[0033]

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[In the formula (14), l is an integer of 1 to 10. ]

[0035]

[Chemical 15]

Specific examples of the compound having 3 to 4 oxetane rings include compounds represented by the following formula (16).

[0037]

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Further, as an example of the compound having 1 to 4 oxetane rings other than the above, there is a compound represented by the following formula (17).

[0039]

[Chemical 17]

In the formula (17), R ⁸ is the same group as in the formula (6). R ¹¹ is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, or a trialkylsilyl group, and r is 1 to 4.

Specific preferred examples of the oxetane compound used in the present invention include the compounds shown below.

[0042]

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[0043]

[Chemical 19]

[0044]

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[0045]

[Chemical 21]

In addition to these, the molecular weight is from 1000 to 5
A compound having a high molecular weight of about 000 and having 1 to 4 oxetane rings is also included. Examples of these include the following compounds.

[0047]

[Chemical formula 22]

Here, p is 20 to 200.

[0049]

[Chemical formula 23]

Here, q is 15 to 100.

[0051]

[Chemical formula 24]

Here, s is 20 to 200.

Photocationic Polymerization Initiator As the photocationic polymerization initiator used in the composition of the present invention, various kinds can be used. Preferred examples of these initiators include diaryliodonium salts and triarylsulfonium salts. A typical cationic photopolymerization initiator is shown below.

[0054]

[Chemical 25]

[0055]

[Chemical formula 26]

[0056]

[Chemical 27]

[0057]

[Chemical 28]

In the formula, R ¹² is a hydrogen atom and has 1 to 18 carbon atoms.
Or an alkoxy group having 1 to 18 carbon atoms, R ¹³ is a hydrogen atom, a hydroxyalkyl group or a hydroxyalkoxy group, and preferably a hydroxyethoxy group. M is a metal, preferably antimony,
X is halogen, preferably fluorine, and k is the valence of the metal, for example 5 in the case of antimony. The cationic photopolymerization initiator is a compound having an oxetane ring and / or a compound having an epoxy group.
Alternatively, when a compound having a vinyl ether group is contained, it is preferably contained in a proportion of 0.1 to 20% by weight, more preferably 0.1 to 20% by weight based on the total amount thereof.
It is 10% by weight. If the amount is less than 0.1% by weight, the curability is not sufficient. On the other hand, if the amount exceeds 20% by weight, the light transmittance is poor and uniform curing cannot be performed or the coating surface is not smooth. The sex may be lost.

In each of the above chemical formulas showing a compound having 1 to 4 oxetane rings or a photocationic polymerization initiator, the groups represented by the same symbol existing in one molecule are the same as each other. It may or may not be.

Other Blends In addition to the above-mentioned essential ingredients, other ingredients may be blended in the composition of the present invention, if necessary. A second invention of the present invention is an active energy ray-curable composition for plastic coating, which further comprises a compound having an epoxy group in the composition of the first invention. In this case, by including an epoxy compound in the composition, the curing rate of the composition can be further improved. Various compounds can be used as the compound having an epoxy group. For example, examples of the epoxy compound having one epoxy group include phenylglycidyl ether and butylglycidyl ether, and examples of the epoxy compound having two or more epoxy groups include hexanediol diglycidyl ether, tetraethylene glycol diglycidyl ether, triglyceride. Examples thereof include methylolpropane triglycidyl ether, bisphenol A diglycidyl ether and novolac type epoxy compounds. Particularly in the present invention, it is preferable to use an alicyclic epoxy compound, and examples thereof include the compounds shown below.

[0061]

[Chemical 29]

[0062]

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[0063]

[Chemical 31]

In this case, the compounding ratio of the compound having an epoxy group is 5 to 95 parts by weight based on 100 parts by weight of the total amount of the compound having 1 to 4 oxetane rings and the compound having an epoxy group. preferable.

A third invention of the present invention is an active energy ray-curable composition for plastic coating, which further comprises a compound having a vinyl ether group in the composition of the first invention. In this case, by including the compound having a vinyl ether group in the composition, the curing rate of the composition can be further improved. Various compounds can be used as the compound having a vinyl ether group. For example, examples of the compound having one vinyl ether group include hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, dodecyl vinyl ether, propenyl ether propylene carbonate and cyclohexyl vinyl ether. Examples of the compound having two or more vinyl ether groups include cyclohexanedimethanol divinyl ether, triethylene glycol divinyl ether, and novolak type divinyl ether. In this case, the compounding ratio of the compound having a vinyl ether group is preferably 5 to 95 parts by weight based on 100 parts by weight of the total amount of the compound having 1 to 4 oxetane rings and the compound having a vinyl ether group.

The fourth invention of the present invention is an active energy ray-curable composition for plastic coating, which further comprises the compound having a (meth) acryloyl group and a photoradical polymerization initiator in the composition of the first invention. In this case, by including a compound having a (meth) acryloyl group in the composition, the composition viscosity can be adjusted and the coating film hardness of the composition can be modified. Various compounds can be used as the compound having a (meth) acryloyl group. Examples of the compound having one (meth) acryloyl group include (meth) acrylates of phenol, nonylphenol and 2-ethylhexanol, and (meth) acrylates of alkylene oxide adducts of these alcohols. Examples of the compound having two (meth) acryloyl groups include bisphenol A, isocyanuric acid, di (meth) acrylate of ethylene glycol and propylene glycol, and di (meth) acrylate of an alkylene oxide adduct of these alcohols. . Examples of compounds having three (meth) acryloyl groups include penta (erythritol), tri (meth) acrylate of trimethylolpropane and isocyanuric acid, and tri (meth) acrylate of an alkylene oxide adduct of these alcohols. Examples of the compound having four or more acryloyl groups include pentaerythritol and poly (meth) acrylate of dipentaerythritol. Further, conventionally known acrylic-based monomers / oligomers such as urethane acrylate having a urethane bond as a main chain, polyester acrylate having an ester bond as a main chain, and epoxy (meth) acrylate obtained by adding acrylic acid to an epoxy compound are also included. In this case, the compounding ratio of the compound having a (meth) acryloyl group is 5 to 95 with respect to 100 parts by weight of the total amount of the compound having 1 to 4 oxetane rings and the compound having a (meth) acryloyl group. Parts by weight are preferred. In the fourth aspect of the present invention, a photoradical polymerization initiator is added to the composition. As the photo-radical polymerization initiator, various ones can be used, and preferred ones are benzophenone and its derivatives, benzoin alkyl ether, 2-methyl [4- (methylthio) phenyl] -2-morpholino-1-propanone. , Benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, alkylphenyl glyoxylate, diethoxyacetophenone, 2-benzyl-2-
Dimethylamino-1- (4-morpholinophenyl)-
Examples thereof include 1-butanone and acylphosphine oxide. The content of these photo radical polymerization initiators is
0.0 for compounds having a (meth) acryloyl group
It is preferably from 1 to 20% by weight.

Further, in the present invention, the composition of the first invention contains one or more selected from the compounds having an epoxy group, the compound having a vinyl ether group and the compound having a (meth) acryloyl group. It can also be blended. In this case, as the compounding ratio of these, the total amount of the compound having a curable component having 1 to 4 oxetane rings, the compound having an epoxy group, the compound having a vinyl ether group and the compound having a (meth) acryloyl group is used. The amount of the compound having 1 to 4 oxetane rings is preferably 5 to 95 parts by weight based on 100 parts by weight.

The composition of the present invention comprises an inorganic filler, a dye, in an amount of up to 100 parts by weight per 100 parts by weight of the curable component.
Inert ingredients such as pigments, viscosity modifiers, treating agents, organic solvents and UV blocking agents can be incorporated.

In addition to the photocationic polymerization initiator and / or the photoradical polymerization initiator, a photosensitizer may be added to the composition of the present invention to adjust the wavelength in the UV region. Typical sensitizers that can be used in the present invention include Clevero [JV Crivello, Adv. In Polymer Sc
i., 62, 1 (1984)], and specific examples thereof include pyrene, perylene, acridine orange, thioxanthone, 2-chlorothioxanthone and benzoflavin.

Method of Use The composition of the present invention is a liquid and can be applied to coating various plastic materials. Examples of the plastic material include polycarbonate, polymethylmethacrylate, polyethylene terephthalate, vinyl chloride resin and ABS resin. Which may be plate-like or fame-like. The film thickness on the surface of the plastic material of the composition of the present invention may be appropriately selected according to the application to be used,
The preferable film thickness is 1 to 50 μm, more preferably 3 to 20 μm. The method of using the composition of the present invention is not particularly limited, and may be performed according to a conventionally known method, for example, dipping, flow coating, spraying, bar coating, gravure coating, roll coating, blade coating or air knife coating. According to the above method, there is a method of applying the composition of the present invention on the surface of a plastic material using a coating machine and then irradiating with active energy rays to cure the composition. Examples of active energy rays include ultraviolet rays, X-rays, and electron rays. As the light source that can be used when it is cured by ultraviolet rays, various light sources can be used, and examples thereof include a pressurized or high pressure mercury lamp, a metal halide lamp, a xenon lamp, an electrodeless discharge lamp or a carbon arc lamp. In the case of curing with an electron beam, various irradiation devices can be used, and examples thereof include Cockloft-Waltsin type, Van de Graaff type, or resonance transformer type, and the electron beam is 50 to 1000e.
Those having an energy of V are preferable, and more preferably 100 to 300 eV. In the present invention, it is preferable to use ultraviolet rays for curing the composition, because an inexpensive device can be used. After applying the composition of the present invention to a plastic material, if necessary, processing such as molding, printing or transfer can be performed. In the case of molding, for example, after heating the plastic material having the composition coating film of the present invention to an appropriate temperature, a plastic material to be formed using a method such as vacuum molding, vacuum pressure molding, pressure molding or mat molding is used. Or a method of forming only a coating film layer such as when embossing on the coating film of the composition of the present invention, such as a CD or a record in which uneven shapes such as interference fringes are formed. Can be mentioned. When printing is performed, an ordinary printing machine is used to print on the coating film by an ordinary method. In the case of transferring, the composition of the present invention is applied to a substrate such as a polyethylene terephthalate film, and if necessary, the above-mentioned printing or embossing is performed, and after applying an adhesive layer, another substrate is applied. Transfer to.

[0071]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples below. The parts in the following examples are based on weight.

Example 1 Preparation of Composition As a compound having an oxetane ring, the following compound (32) having the following two oxetane rings (hereinafter referred to as component A)
100 parts and 4 parts of the following compound (33) (hereinafter referred to as component G) as a cationic photopolymerization initiator were mixed with stirring to produce an active energy ray-curable composition for plastic coating.

[0073]

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[0074]

[Chemical 33]

Evaluation The obtained composition was applied to a transparent polycarbonate plate in an amount of 10
It is coated at a thickness of μm, and it is applied at a conveyor speed of 80 W / cm at a position 10 cm from the bottom of the concentrating high-pressure mercury lamp.
Under a condition of 10 m / min, it was repeatedly passed under a mercury lamp to be cured. The following evaluations were performed on the obtained compositions and cured films. The results are shown in Table 2 below.

Curable Property Under the above-mentioned curing conditions, the number of passes (the number of passes) until the tackiness disappeared from the surface was evaluated.

Adhesion Adhesion of the obtained coating film was evaluated according to the JIS X 5400 X-cut tape method. In Table 2, ○, △
And x have the following meanings. ◯: JISK 5400 scored 10 or 8 Δ: JISK 5400 scored 6 or 4 ×: JISK 5400 scored 2 or 0

○ Transparency The haze value of the obtained coating film was measured according to JIS7105. (Cloudy Value = Td / Tt × 100, Td: Scattered Light Transmittance, Tt: Total Light Transmittance) In Table 2, ◯, Δ and x have the following meanings. ○: less than 1% △: 1 to 5% ×: more than 5%

Scratch resistance The coating film surface was scratched with steel wool # 0000, and the degree of scratching was visually observed. In Table 2, ◯, Δ and × have the following meanings. ◯: Almost no scratches were found Δ: Slight scratches were found ×: Many scratches were found

Surface smoothness The surface of the obtained coating film was visually observed. In Table 2, ◯, Δ and × have the following meanings. ◯: Good Δ: A little disordered ×: Many disordered

Examples 2 to 6 Compositions were produced in the same manner as in Example 1 except that the components having the compositions shown in Table 1 were used. An active energy ray-curable composition for plastic coating was produced in the same manner as in Example 1 using the obtained composition. The obtained cured film was evaluated in the same manner as in Example 1. Table 2 shows the results.

Comparative Examples 1 to 3 Compositions were produced in the same manner as in Example 1 except that the components having the compositions shown in Table 1 were used. An active energy ray-curable composition for plastic coating was produced in the same manner as in Example 1 using the obtained composition. The obtained cured film was evaluated in the same manner as in Example 1. Table 2 shows the results.

[0083]

[Table 1]

In Table 1, each numeral indicates a part. Further, in Table 1, components B to H represent the following compounds.

Component B [compound of formula (34) below having 3 oxetane rings]

[0086]

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Component C [compound of formula (35) below having one oxetane ring]

[0088]

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Component D [compound of formula (36) below having two epoxy groups]

[0090]

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Component E [compound of the following formula (37) having two vinyl ether groups]

[0092]

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Component F [compound of formula (38) below having two acryloyl groups]

[0094]

[Chemical 38]

Component H [compound of the following formula (39) which is a photo-radical polymerization initiator]

[0096]

[Chemical Formula 39]

[0097]

[Table 2]

Example 7 Evaluations were made in the same manner as in Example 1 except that the compositions of Examples 1 to 6 were used and a 100 μm thick polyethylene terephthalate film and a 150 μm thick polyvinyl chloride film were used. Good results were obtained as in the case of using a polycarbonate plate.

[0099]

EFFECT OF THE INVENTION The active energy ray-curable composition for plastic coating of the present invention has a fast curing rate, and its coating film is excellent in adhesion, scratch resistance and surface smoothness, and is particularly a hard coat for plastics. It is useful for business.

Claims (4)

[Claims] 1. An active energy ray-curable composition for plastic coating, comprising a compound having 1 to 4 oxetane rings and a photocationic polymerization initiator. 2. The active energy ray-curable composition for plastic coating according to claim 1, further comprising a compound having an epoxy group. 3. The active energy ray-curable composition for plastic coating according to claim 1, further comprising a compound having a vinyl ether group. 4. The active energy ray-curable composition for plastic coating according to claim 1, 2 or 3, further comprising a compound having a (meth) acryloyl group and a photoradical polymerization initiator.