JPH09235310A - Photocurable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photocurable composition curable by visible light, capable of curing by relatively low energy and capable of fading color of a catalyst after curing. SOLUTION: This photocurable composition comprises (A) 100 pts.wt. radically polymerizable vinyl compound, (B) 0.5-5.0 pts.wt. diaryl iodium, (C) 0.1-4.0 pts.wt. tertiary amine and (D) 0.01-0.1 pt.wt. thiazine-based dye. The composition rapidly cures by a visible light and is excellent in deep curing property. A resin colored before curing is made to fade after photocuring. Therefore, the composition can be used in places limited in use because of colored composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable composition, which is used for adhesion, sealing, sealing of metal, plastic, ceramic parts, etc., or surface coating of metal, plastic, ceramic, wood, stone, etc. And shows high sensitivity to light rays in the visible light range,
In addition, the present invention relates to a photopolymerizable composition characterized in that the color of the resin fades after curing.

[0002]

2. Description of the Related Art Conventionally, many methods for obtaining a cured product by irradiation with light have been known, most of which are based on ultraviolet rays or light having a short wavelength in the range. However, in recent years, there are many cases where the wavelength range of the irradiation light is not the conventional ultraviolet light range but the light of a longer wavelength range, particularly the visible light range. For example, benzoyl, benzoin alkyl ether, benzyl ketal, benzophenone, anthraquinone, benzyl, or Michler's ketone has been used. However, these photopolymerization initiators are
Compared to the photopolymerization initiating ability for a light source in the ultraviolet region of 00 nm or less, that for a light source in the visible light region of 400 nm or more is remarkably low, and therefore, the range of application of photopolymerization compositions containing them has been limited.

Therefore, several proposals have hitherto been made regarding a photopolymerization sensitizer containing a photopolymerization initiator system capable of responding to light rays in the visible region. For example, a composite photoinitiator system of a dye and an aliphatic amine (Japanese Patent Publication No. 44-20189), a system of hexaarylbisimidazole and dialkylaminobenzylidene ketone (Japanese Patent Publication No. 47-2528), a system of (keto) coumarin (Japanese Patent Publication No. 52-112681), a system of bisimidazole and indanone (JP-A-54-15529).
2), system of triazine derivative and cyanine dye
8-29803), coumarin-based dyes and diaryliodonium salts (JP-A-60-88005), benzophenone derivatives and amino acid derivatives (JP-A-61-173).
242), a system of titanocene (Japanese Patent Laid-Open No. 63-4148).
4), a system of metal arene complex (JP-A-2-29680)
2), a system of squarylium dye and dialkylaniline (JP-A-5-311093).

[0004]

However, although many of these techniques certainly have sensitivity to visible light, when compared in terms of relative sensitivity, there is a drawback that they are insufficient from a practical point of view. . From this, a photocurable composition that is cured with lower energy in practical use is desired, and in particular, it is expected that the curing rate is about the same as the curing by ultraviolet rays and that the cured physical properties at that time are equivalent. It

Further, the light source required for curing is inexpensive,
Curing is possible even with the irradiation light amount of an incandescent lamp,
As described above, fast curability is required.

The present invention has been made to solve such problems, and an object thereof is to provide a photocurable composition which is cured by a low energy such as visible light. Further, most of these visible light curable resins retain the color of the sensitizer used even after photocuring, and thus their use may be limited in practical use. Furthermore, since the sensitizers used are low molecular weight compounds, they remain in the system after photocuring and induce the filter effect of the sensitizer at the time of photocuring. There was a limit to sex.

[0007]

[Means for Solving the Problems] The inventors of the present invention have made earnest studies to overcome such difficulties and obtain an excellent photocurable composition, and as a result, a composition comprising the following components was found to be visible. It was found that an active radical is generated under irradiation of a light ray, a cured product can be rapidly obtained by a reaction with a polymerizable functional group, and fading can be performed after curing, and the present invention has been completed. The above composition is as follows. A) 100 parts by weight of radically polymerizable vinyl compound B) 0.5 to 5.0 parts by weight of diaryl iodonium salt C) 0.1 to 4.0 parts by weight of tertiary amine D) 0.01 to 0. 1 part by weight

The details of each component constituting the present invention will be described below. The radically polymerizable vinyl compound which is the component A of the present invention is not particularly limited as long as it is a compound having a radically polymerizable vinyl group in the molecule. Specific examples of the polymerizable vinyl compound include the following. (1) Vinyl compound 1 A (meth) acrylate represented by the following 1.

[0009]

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(In the formula, R ₁ represents —H or —CH ₃ ,
R ₂ is a substituted alkyl group having 1 to 2 or more H atoms substituted with an —OH group in a linear or branched alkyl group having 2 to 4 carbon atoms. ) As preferable specific examples of the (meth) acrylate represented by the above formula 1, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2
-Hydroxybutyl (meth) acrylate, 1,2-dihydroxyethyl (meth) acrylate and the like.

(2) Vinyl compound 2 A (meth) acrylate represented by the following two formulas.

[0012]

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(In the formula, R ₃ represents —H or —CH ₃ ,
R ₄ represents a hydrocarbon group of -H or a _C 1 -C _4, n is an integer from 1 to 10. ) Preferred specific examples of the (meth) acrylate represented by the above formula 2 are dicyclopentenyl (meth) acrylate, dicyclopentenyloxymethyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate and dicyclopentenyloxy. Examples include propyl (meth) acrylate.

(3) Vinyl compound 3 A (meth) acrylate represented by the following three formulas.

[0015]

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(In the formula, R ₅ represents —H or —CH ₃ ,
R ₆ is —H or a C _{1 to} C ₁₈ alkyl group, or C
Cycloalkyl group ₅ -C _20, phenyl group, tetrafurfuryl group, an alkyl group of _C 5 _{-C 20} containing these groups shown. ) Preferred specific examples of the (meth) acrylate represented by the above three formulas include (meth) acrylic acid, methyl (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, and 2-ethylhexyl (meth). ) Acrylate, phenyl (meth)
There are acrylate, benzyl (meth) acrylate and the like.

(4) Vinyl Compound 4 A (meth) acrylate represented by the following four formulas.

[0018]

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(In the formula, R ₇ represents —H or —CH ₃ ,
R _{8 represents} an alkyl group of C 1 _{-C 20,} vinyl group, an aryl group, an alkoxyalkyl group. ) Preferred specific examples of the (meth) acrylate represented by the above formula 4 include methoxycarbonylmethyl (meth) acrylate, ethoxycarbonylmethyl (meth) acrylate, heptoxycarbonylmethyl (meth) acrylate, isopropylcarbonylmethyl (meth) acrylate. Etc.

(5) Vinyl Compound 5 A (meth) acrylate represented by the following formula (5).

[0021]

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(In the formula, R ₉ represents —H or —CH ₃ ,
R ₁₀ is isophorone diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate,
The reaction residue generated by the condensation reaction with OH, R _11, is
C _{1 to} C ₈ hydrocarbons, those having an ester bond, a carbonate bond, an ether bond, and a thioether bond in these hydrocarbons, and n represents an integer of 1 to 20. ) Preferred specific examples of the (meth) acrylate represented by the above formula 5 include polyethylene glycol-modified urethane acrylate, polyester-modified urethane acrylate,
Examples include polycarbonate-modified urethane acrylate, polyether-modified urethane acrylate, polythioether-modified urethane acrylate, and the like.

(6) Vinyl Compound 6 A (meth) acrylate represented by the following 6 formula.

[0024]

[Chemical 6]

(In the formula, R ₁₂ represents —H or —CH ₃ , R ₁₃ represents a C _{2 to} C ₈ hydrocarbon, and n is 1 to 1).
Indicates an integer of 10. ) As preferable specific examples of the (meth) acrylate represented by the above formula 6, 2,2-bis (4-methacryloxydiethoxyphenyl) propane, 2,2-bis (4-allyloxydiethoxyphenyl) propane, 2,2-bis (4
-Methacryloxytriethoxyphenyl) propane,
2,2-bis (4-acryloxypentaethoxyphenyl) propane, 2,2-bis (4-methacryloxyhexaethoxyphenyl) propane, 2,2-bis (4-acryloxydipropoxyphenyl) propane, 2 , 2-bis (4-acryloxydibutoxyphenyl) propane,
2,2-bis (4-methacryloxyoctabutoxy) propane, 2- (4-matacryloxyethoxyphenyl)
-2- (4-methacryloxyethoxyphenyl) propane, 2- (4-acryloxydipropoxyphenyl)-
2- (4-acryloxytriethoxyphenyl) propane and the like.

(7) Other Radical Polymerizable Vinyl Compounds In addition to the above radical polymerizable vinyl compounds, A of the present invention
Examples of the component include isobornyl (meth) acrylate, vinyl acetate, vinyl propionate, styrene, α-methylstyrene, N-vinylpyrrolidone, polybutadiene acrylate, and silicone acrylate. As the A component in the present invention, one kind or a mixture of two or more kinds of the above radically polymerizable vinyl compounds can be used.

The diaryliodonium salt which is the component B of the present invention is disclosed in JP-A-54-53181 and JP-B-53-328.
31 and Japanese Patent Publication No. 62-36015 and the like, which are already known, have an alkyl group in the molecule, and are selected from the group consisting of BF ₄ , PF ₆ , SbF ₆ , and A _S F _{6 as} the counter anion. This is a type of information that can be obtained. The details of the radical generation mechanism using the diaryl iodonium salt as the component B of the present invention are not critical, but the photooxidation-reduction sensitizer by hydrogen abstraction due to the interaction between the thiazine dye and the tertiary amine is used. It is considered that the absorption wavelength apparently shifts to the long wavelength side due to the sensitizing action in the dye molecule and a radical is generated by irradiation with visible light. Furthermore, it is considered that the dye that has completed the electron transfer loses its color development because the π-electron conjugation is broken due to the change in the molecular structure.

The amount of component B added is preferably a stoichiometric amount sufficient to impart photocurability to the composition,
Depending on the radical polymerizable compound used, it is 0.5 to 5.0 with respect to 100 parts by weight of the radical polymerizable compound.
Parts by weight, preferably 1.0 to 3.0 parts by weight. When this amount is less than 0.5 parts by weight, the sensitivity is not significantly affected, and when it is more than 5.0 parts by weight, the discolorability of the composition decreases and the reaction rate of the resin decreases.

The term "fading" as used in the present invention means that the color of the catalyst system disappears after the catalyst system color of the uncured product is cured by irradiation with light. The catalyst used for the visible light curable resin always has a color because it absorbs visible light. Therefore, in the conventional visible light curable resin, the entire photo curable resin becomes colored even if the oligomer or monomer as the component A is transparent. The color of the catalyst of the present invention fades when irradiated with light. This does not have a function of erasing the color itself of the A component, but the resin after curing can be made transparent by selecting a transparent A component.

In the present invention, the component C used as a proton donor in combination with the diaryliodonium salt exhibits its effect with both aliphatic and aromatic tertiary amines. Suitable examples of the tertiary amine used in the present invention include trimethylamine, triethylamine, tributylamine, N, N'-diethanolamine, N, N'-dimethyl-P-toluidine, N, N'-.
Dimethyl-aniline, N-methyl-diethanolamine, N-methyl-dimethanolamine, N, N '-(dimethylamino) ethyl-methacrylate, N, N'-dimethylamino-acetophenone, N, N'-dimethylaminobenzophenone, N, N'-diethylamino-benzophenone and the like.

The preferred addition amount of the component C in the present invention is a stoichiometric amount sufficient to impart photocurability, and although it varies depending on the radical polymerizable compound used, 100 parts by weight of the radical polymerizable compound is used. With respect to 0.1 to 4.0 parts by weight, preferably 1.0 to 3.0 parts by weight. If this amount is less than 0.1 part by weight, sufficient sensitivity cannot be obtained and curing is affected. On the other hand, if the amount is more than 4.0 parts by weight, the curing of only the surface will proceed, which will strongly affect the curability in the deep part and the color fading property will be extremely deteriorated.

As the component D of the present invention, a thiazine dye is used. A dye may be used as a sensitizer for a visible light curing catalyst, but the diaryl iodonium salt is limited to a thiazine dye. In other dyes, the combination of diaryl iodonium salt / tertiary amine does not show sensitivity to light in the visible light region, but rather acts as a desensitizer. Among the thiazine dyes used in the present invention, methylene blue and thionine are most effective.

The amount of component D added is preferably a stoichiometric amount sufficient to impart photocurability, and although it varies depending on the radical polymerizable compound used, it is based on 100 parts by weight of the radical polymerizable compound. It is 0.01 to 0.1 part by weight, preferably 0.5 to 0.7 part by weight. If this amount is less than 0.01 parts by weight, sufficient sensitivity cannot be obtained and curing is affected. On the other hand, if the amount is more than 0.1 parts by weight, the curability in the deep part is strongly affected and the fading property becomes extremely poor.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.

Epoxy acrylate as component A,
50 parts by weight of (2,2-bis (4-methacryloxygetoxyphenylpropane)) and 50 parts by weight of isobornyl acrylate, a diphenyliodonium salt as the B component,
As component C, diethanolamine, dimethylaniline,
As component D, methylene blue and thionine were blended in the amounts shown in Table 1, and the periphery of the blending container was protected from light by an aluminum foil.
A uniform preparation liquid was prepared by mixing and stirring while heating at 0 ° C. In addition, as comparative examples, the compounds shown in Table 1 were prepared in the same manner.

[0036]

[Table 1]

In the curing experiment, each of the prepared resins was treated with a diameter of 32
2 g was weighed in a polyethylene container of φ × 10 mm in height, and the time until complete curing was measured using a 100 W halogen lamp. The irradiation conditions are a lamp distance of 1 cm and a central illuminance of 9.8 to 10.0 mW / cm ² . The thick film curability of the cured product was measured by pouring the resin into a jig having a diameter of 5φ and a height of 30 mm, irradiating with light under the same conditions as above, and removing the uncured part as the true cured film thickness. .

The gel fraction was calculated from the weight change after soxhlet pouring of each of the obtained cured products using xylene as a solvent for 5 hours and drying at 100 ° C. for 2 hours. The results are shown in Table 2.

[0039]

[Table 2]

[0040]

As is apparent from the above description, the photocurable composition of the present invention can be rapidly used in a light source having a low energy density by the action of the diaryl iodonium salt, the tertiary amine and the thiazine dye. It was cured and found to be superior to conventional visible light curing compositions. Further, in the conventional visible light curable resin, the visible light catalyst is colored, and the resin after curing remains colored, but when the catalyst of the present invention is used, the color of the resin after curing is discolored. Therefore, the color of the resin after curing can be adjusted to any color. Particularly, if a transparent vinyl compound produced by radical polymerization is selected, the resin after curing becomes transparent. This is a characteristic that conventional visible light curable resins do not have. From these facts, the present invention can be used as a photocurable resin such as an adhesive, a coating agent, a sealant, and a casting resin which can be cured by irradiation with visible light.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09D 171/00 PDW C09D 171/00 PDW 175/14 PDZ 175/14 PDZ // C08F 20/12 MLY 7824-4J C08F 20/12 MLY 20/26 MMK 20/26 MMK 299/02 MRR 299/02 MRR MRS MRS 299/04 MRT 299/04 MRT 299/06 MRX 299/06 MRX

Claims (1)

[Claims] 1. A photocurable composition comprising the following components A, B, C and D: A) 100 parts by weight of radically polymerizable vinyl compound B) 0.5 to 5.0 parts by weight of diaryl iodonium salt C) Tertiary amine 0.1-4.0 parts by weight D) Thiazine-based dye 0.01-0.1 parts by weight