JPH0411858B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a photocurable resin composition that is easily cured by light, particularly ultraviolet light. In recent years, the use of photocurable resins has been attracting attention as a method of curing paint films that can be done at room temperature and at high speed by irradiation of light, instead of the methods of curing paint films using heat or drying at room temperature for a long time. . However, the most important characteristic required of photocurable resins is photocurability, and as a result of intensive study, the present inventors found that epoxy ester resins having photopolymerizable unsaturated groups and photopolymerizable It has been found that a resin composition in combination with an isocyanurate derivative having an unsaturated group has excellent photocurability. That is, the present invention provides (A) an acrylic ester or methacrylic ester of an epoxy compound having two or more epoxy groups in one molecule, (B) an acrylic ester or methacrylic ester of the epoxy compound of (A) The present invention relates to a photocurable resin composition containing an isocyanate-modified epoxy ester obtained by reacting with an isocyanate, (C) an acrylic or methacrylic ester of tris(hydroxyalkyl)isocyanurate, and (D) a photopolymerization initiator. In the present invention, epoxy compounds containing two or more epoxy groups in one molecule include, for example, diglycidyl ethers obtained by reacting bisphenols such as bisphenol A or hydrogenated products thereof with epichlorohydrin, and aromatic dicarboxylic acids. It is an epoxy compound represented by diglycidyl ester obtained by the reaction of the hydrogenated product and epichlorohydrin, and polyglycidyl ether obtained by the reaction of polyhydric alkane alcohol and epichlorohydrin. Preferably, one or more epoxy compounds of 140 to 1000 are used. The acrylic ester or methacrylic ester of an epoxy compound, which is component (A) of the present invention, is obtained by an ester addition reaction between the above-mentioned epoxy compound and acrylic acid or methacrylic acid. This has an equivalent ratio of epoxy group/carboxyl group of 1/0.5 to 1/1, preferably 1/0.8 to 1/1.
It is obtained by blending an epoxy compound and acrylic acid or methacrylic acid so as to cause a reaction. The reaction is carried out in a conventional manner, for example, in the presence of a basic catalyst at 60 to
It is obtained by reacting at 120°C until the acid value reaches 0 to 20. The acrylic ester and methacrylic ester of the epoxy compound thus obtained are polyhydroxy compounds containing hydroxyl groups. Therefore, an isocyanate-modified epoxy ester can be obtained by reacting the above polyhydroxy compound with a polyisocyanate. As described above, the isocyanate-modified epoxy ester which is the component (B) of the present invention is obtained by crosslinking or increasing the molecular weight of each acrylic ester or methacrylic ester of an epoxy compound with a polyisocyanate. In this case, by varying the amount of polyisocyanate used, various molecular weight distributions can be adjusted, and the flexibility etc. of the coating film can be adjusted. In the above reaction, the hydroxyl group (OH group) in the acrylic ester or methacrylic ester of the epoxy compound and the isocyanate group (NCO group) in the polyisocyanate compound have an equivalent ratio of NCO group/OH group of 1/1 or less, especially 0.7. The reaction is preferably carried out in the presence of a catalyst such as a tin compound such as dibutyltin dilaurate, dibutyltin di-2-ethylhexoate, dibutyltin diacetate, or the like. It is carried out at a temperature of 20-80 °C in the presence of If the equivalent ratio exceeds 1/1, free NCO groups remain, causing problems in the storage stability of the resin composition. Examples of the polyisocyanates include monomers such as tolylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, and cyclohexylmethane diisocyanate, and cyclized trimers of tolylene diisocyanate and isophorone diisocyanate rings. Trimers with an isocyanurate ring such as trimeric trimers, multimers such as Biuret-type trimers of hexamethylene diisocyanate, and even these polyisocyanates with propanediol, butanediol, hexanediol, polyethylene glycol, By reaction with a polyhydric alcohol compound such as methylolpropane or pentaerythritol, a part of the product preferably contains a compound in which two or more isocyanate groups remain in one molecule. Component (C) of the present invention includes acrylic esters or methacrylic esters of tris(hydroxyethyl)isocyanurate, tris(hydroxypropyl)isocyanurate, and tris(hydroxybutyl)isocyanurate. Here, triesters account for 85% by weight of esters.
It is preferable to include the above in order to efficiently achieve the effects of the present invention. Therefore, the ester may include diester and monoester. In the photocurable resin composition according to the present invention, it is desirable to use a photopolymerizable monomer other than the component (C) and an organic solvent as necessary. Such monomers include butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, cyclohexyl acrylate, ethylene glycol diacrylate, 1,6-hexanediol diacrylate, butanediol diacrylate, neopentyl glycol diacrylate, trimethylol Acrylic acid esters such as propane triacrylate and polyethylene glycol diacrylate,
and butyl methacrylate, 2-ethylhexyl methacrylate, decyl methacrylate, cyclohexyl methacrylate, ethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, butanediol dimethacrylate, neopentyl glycol dimethacrylate,
Examples include methacrylic acid esters such as trimethylolpropane trimethacrylate and polyethylene glycol dimethacrylate, and vinyl compounds such as styrene and vinyltoluene. Examples of organic solvents include aromatic hydrocarbons such as benzene, xylene and toluene, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and esters such as ethyl acetate and butyl acetate. Among the photopolymerizable components mentioned above, photopolymerizable components other than component (C) are particularly those that do not have unsaturated double bonds other than photopolymerizable unsaturated bonds in each molecule, in other words, photopolymerizable unsaturated bonds. Compounds that are saturated except for saturated bonds have excellent weather resistance, so they are especially suitable for paints for building materials (particularly for exterior building materials). The photopolymerization initiator that is component (D) of the present invention includes benzophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl, diacetyl, acetophenone, 2,2-dimethoxy-2-phenylacetophene, etc. These include carbonyl compounds such as non- and anthraquinone, sulfides, and halides. Furthermore, if necessary, triethylamine, 2-dimethylaminoethanol, N-methyldiethanolamine, triethanolamine, 3-dimethylamino-1-propanol, 2-dimethylamino-2-methyl-1, which is effective as a photosensitizing agent.
- Alkyl and alkanolamines such as propanol can be used in combination. In the present invention, the amount of component (C) is 4 to 200 parts by weight, and the amount of photopolymerizable monomers other than component (C) is 0 to 100 parts by weight of the total of components (A) and (B). Preferably, 400 parts by weight are used. If component (C) is less than 4 parts by weight per 100 parts by weight of components (A) and (B) combined, the effect of improving photocurability due to the use of component (C) will be small; Beyond the section
The effect of improving photocurability due to the use of components (A) and (B) is reduced. In addition, if the photopolymerizable monomer other than component (C) is used in an amount exceeding 400 parts by weight per 100 parts by weight of components (A) and (B), the photocurable resin composition according to the present invention may Photocurability decreases.
Each photopolymerizable monomer other than component (C) and component (C) is used within the range of the above formulation. Other photopolymerizable monomers] It is preferable to use the photopolymerizable monomers in an amount of 5 to 50% by weight and 20 to 50% by weight based on the total amount. In addition, in the present invention, the organic solvent is used for the main purpose of reducing the viscosity of the resin composition, so there is no restriction on the amount used, but it is 0 to 100 parts by weight per 100 parts by weight of the photocurable component. From the viewpoint of resource and energy conservation, it is preferable to use it at a certain level. When the photopolymerization initiator (D) component is used in combination with a photosensitizing aid, the total amount thereof is 0.5 to 15% by weight, preferably 2 to 8% by weight, based on the total amount of photopolymerization components.
The photosensitizing aid is preferably used in an amount of 3 mol or less per 1 mol of the photopolymerization initiator. Furthermore, the resin composition of the present invention may contain various additives, such as polymers such as acrylic resin, ketone resin, polyester resin, polyethylene, polypropylene, and polyvinyl acetate, pigments such as titanium white, aluminum powder, Spherical or flaky fillers that reflect or transmit light such as mica flakes, talc, and kaolin, plasticizers such as diallyl phthalate, dyes, and the like can be added for the purpose of improving various properties. Next, Examples and Comparative Examples will be given. Synthesis Example 1 In a reactor: 192 parts by weight of Syodyne 540 [trade name (Showa Denko Co., Ltd. (hexahydrophthalic acid diglycidyl ester), epoxy equivalent: 160]) 188 parts by weight of DRH-151 [trade name (Water) by Ciel Kagaku Co., Ltd. Added bisphenol A
(type diglycidyl ether), epoxy equivalent: 235] 144 parts by weight of acrylic acid, 1 part by weight of triethylamine, and 0.1 part by weight of hydroquinone were heated and stirred at 90 to 100°C for about 15 hours to determine the acid value.
10 epoxy acrylate (a) was obtained. Example 1 40 parts by weight of the epoxy acrylate (a) of Synthesis Example 1, 20 parts by weight of ethyl acetate, and 0.01 part by weight of dibutyltin dilaurate were charged into a reactor to make a homogeneous solution, and then trimethylhexamethylene diisocyanate was added at 60°C.
7 parts by weight [Mixture of 2,2,4-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate, NCO content 40
% by weight] was added and stirred under heat for about 4 hours, and the reaction was continued until the isocyanate group disappeared to obtain an isocyanate-modified epoxy ester (b). Next, isocyanate-modified epoxy ester (b)
67 parts by weight Acrylic ester of trishydroxyethyl isocyanurate 25 parts by weight [93% by weight of triester, 7% by weight of diester] 1,6-hexanediol diacrylate
A photocurable resin composition was obtained by mixing and dissolving 28 parts by weight of benzophenone, 3 parts by weight, and 2 parts by weight of triethanolamine.
The resin composition was applied to a Bonderite #144 treated steel plate and left at 40°C for 10 minutes so that the film thickness became 30 to 40μ with 50% by weight or more of the ethyl acetate in the resin composition volatilized. It was adjusted and used as a test plate. The test results are shown in Table 1. Comparative Example 1 Epoxy acrylate (a) of Synthesis Example 1 50 parts by weight Trimethylolpropane triacrylate
25 parts by weight 1,6-hexanediol diacrylate
A photocurable resin composition was obtained by mixing and dissolving 25 parts by weight of benzophenone, 3 parts by weight, and 2-dimethylaminoethanol.
The test was conducted in the same manner as in Example 1. Comparative Example 2 Epoxy acrylate (a) of Synthesis Example 1 50 parts by weight 1,6-hexanediol diacrylate
A photocurable resin composition was obtained by mixing and dissolving 50 parts by weight of benzophenone, 3 parts by weight, and 2-dimethylaminoethanol.
The test was conducted in the same manner as in Example 1. Comparative Example 3 Isocyanate-modified epoxy ester (b) of Example 1 67 parts by weight Trimethylolpropane triacrylate
25 parts by weight 1,6-hexanediol diacrylate
A photocurable resin composition was obtained by mixing and dissolving 28 parts by weight of benzophenone, 3 parts by weight, and 2 parts by weight of triethanolamine.
The test was conducted in the same manner as in Example 1. Comparative Example 4 Pentaerythritol 136 parts by weight phthalic anhydride 296 parts by weight dehydrated castor oil fatty acid 570 parts by weight Parts by weight of water of condensation were obtained. Thereafter, xylene was distilled off to obtain a pale yellow, highly viscous alkyd resin with an acid value of 130. Furthermore, 500 parts by weight of the above alkyd resin, 165 parts by weight of glycidyl methacrylate ester, 3.4 parts by weight of hydroquinone, and 6.8 parts by weight of triethylamine were charged into a reactor and reacted at 70°C for 8 to 10 hours to form a photocurable composition (c) with an acid value of 17. I got it. Next, photocurable composition (c) 50 parts by weight tris(hydroxyethyl)isocyanurate triacrylate 25 parts by weight 1,6-hexanediol diacrylate
A photocurable resin composition was obtained by mixing and dissolving 25 parts by weight of benzophenone, 3 parts by weight, and 2 parts by weight of 2-dimethylaminoethanol.
The test was conducted in the same manner as in Example 1.

【table】

[Table] The photocurable resin composition of the present invention has excellent curability.

Claims (1)

[Scope of Claims] 1 (A) an acrylic ester or methacrylic ester of an epoxy compound having two or more epoxy groups in one molecule; (B) an acrylic ester or methacrylic ester of the epoxy compound of (A); A photocurable resin composition comprising an isocyanate-modified epoxy ester obtained by reacting with a polyisocyanate, (C) an acrylic or methacrylic ester of tris(hydroxyalkyl)isocyanurate, and (D) a photopolymerization initiator. 2. The photocurable resin composition according to claim 1, wherein component (A) and component (B) are compounds having no unsaturated groups other than photopolymerizable unsaturated groups. 3. The photocurable resin composition according to claim 1 or 2, wherein 85% by weight or more of component (C) is triester.