JPH0245642B2 - TORYOYOJUSHISOSEIBUTSU - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition for paint that has excellent weather resistance and durability. Paints are required to have excellent weather resistance because they are exposed to sunlight. In order to improve such weather resistance, ultraviolet absorbers such as benzophenone, benzotriazole, and salicylic acid esters are added to paints. However, since such UV absorbers are low molecular weight compounds, (1) they may be extracted from the base polymer by water, solvents, etc., or sublimated by heat, resulting in decreased durability; (2) incompatibility with polymers; Problem (3): It has drawbacks such as deterioration of the physical properties of the polymer. The present inventors have conducted extensive research to obtain a polymer free of such defects, and as a result, have completed the present invention. That is, the present invention relates to (A) general formula (In the formula, R ₁ is -H or -CH ₃ , R ₂ is -H or -OH, R ₃ is -H, -OH, -OR ₄ or

[Formula] R ₄ is an alkyl group having 1 to 18 carbon atoms)
0.05 to 10% by weight (abbreviated simply as %) (B) At least one monomer selected from styrene, acrylonitrile, and alkyl methacrylate 20 to 99.95% (C) Other copolymerizable monomers 0 to 79.95% A resin composition for coating material containing a polymer is provided. The amount of the monomer represented by the above general formula used in the present invention is 0.05 to 10%, preferably 0.1 to 3%, but if the amount is less than 0.05%, sufficient weather resistance will not be provided; Exceeding this is not preferable as it may cause problems with the painted surface condition, gloss, leveling, etc. Representative examples of such monomers include: 2-Hydroxy-4-(meth)acryloxybenzophenone 2,2-dihydroxy-4-(meth)acryloxybenzophenone Examples include 2,2'-dihydroxy-4,4'-di(meth)acryloxybenzophenone. Moreover, the monomer of the above general formula is usually combined with acrylic acid chloride or methacrylic acid chloride and 2,4
-dihydroxybenzophenone or its derivatives. A specific synthesis example is shown below. 12 parts (by weight) of sodium hydroxide and methanol
Dissolve 64.2 parts of 2,4-dihydroxybenzophenone into the solution prepared by mixing 200 parts. Next, the solvent is distilled off in vacuo, and the remaining monosodium compound is dried and suspended in 500 parts of anhydrous benzene. 27 parts of acrylic acid chloride was cooled and added dropwise to this while stirring, and the mixture was stirred at room temperature for 1 hour and briefly heated to 60°C.
The sodium chloride formed is filtered off with suction. Benzene is distilled off from this filtrate in vacuo to obtain the acrylic acid ester as an oily residue. This acrylic ester crystallizes when an ethanol aqueous solution is added. If the crystals thus obtained are crystallized twice from an aqueous ethanol solution, 2-hydroxy-
4-Acryloxybenzophenone Approximately 51 parts (64% of the theoretical amount) has a melting point of 80°C (uncorrected)
Obtained as yellow shiny flaky crystals. In the present invention, the amount of at least one monomer selected from styrene, acrylonitrile, and methacrylic acid alkyl ester is 20 to 99.95%, preferably 35 to 99.9%, but if the amount is less than 20%, the hardness of the coating film , solvent resistance, stain resistance, etc. are deteriorated, which is not preferable. Among these monomers, the methacrylic acid alkyl ester is preferably one in which the alkyl group has 1 to 4 carbon atoms, and specifically, methyl methacrylate, ethyl methacrylate, n-methacrylate, etc.
propyl, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate,
Examples include sec-butyl methacrylate and ter-butyl methacrylate. Other copolymerizable monomers used in the present invention include, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, lauryl methacrylate, vinyltoluene, α
-Methylstyrene, dimethylstyrene, (meth)
Acrylamide, N-methylol (meth)acrylamide, vinyl acetate, diethyl maleate, dibutyl maleate, diethyl fumarate, dibutyl fumarate, diethyl itaconate, dibutyl itaconate, 2-hydroxyethyl (meth)acrylate,
2-Hydroxypropyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, ethylene glycol di(meth)acrylate, glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, ethylglycidyl (meth)acrylate, ( Examples include meth)acrylic acid, maleic acid (anhydride), fumaric acid, itaconic acid, monobutyl maleate, monobutyl fumarate, monobutyl itaconate, and the like. These monomers can be used in combination of two or more. Copolymers of the above monomers can be easily obtained by known methods such as emulsion polymerization, suspension polymerization, and bulk polymerization, but it is extremely convenient to produce them by solution polymerization. In this case, polymerization is usually carried out in a hydrocarbon solvent such as toluene, xylene, ethylbenzene or ethylcyclohexane, or a mixture thereof; an alcohol solvent such as n-butanol; an ester solvent such as butyl acetate; a ketone solvent such as methyl isobutyl ketone. ; Alternatively, the reaction may be carried out in an ether alcohol solvent such as cellosolve alone or in a combination of two or more. In that case, the temperature is room temperature ~
A temperature of 200°C and a reaction time of 2 to 30 hours are appropriate. In addition, as a polymerization initiator, a peroxide such as benzoyl peroxide or di-tert-butyl peroxide; or an azo compound such as azobisisobutyronitrile is used, and polymerization can also be carried out using a known and commonly used redox system. It is possible. Furthermore, if necessary, it is also possible to adjust the molecular weight using a chain transfer agent such as lauryl mercaptan or octyl thioglycolate. Separately, if necessary, the copolymer thus obtained may be used during or after its production, such as unsaturated polyester resins, alkyd resins, etc.
It can also be modified with epoxy resins or natural or synthetic resin acids. The copolymer thus obtained preferably has a number average molecular weight in the range of about 1,000 to 100,000. The resin composition of the present invention has this copolymer as its main component, and if necessary, an appropriate curing agent is added thereto, and cured with excellent performance by drying at room temperature or baking at 60°C to 300°C. A coating film can be obtained. The coating form of the resin composition of the present invention can be a solvent type, a liquid non-solvent type, a water-soluble type, a water-dispersible type, a powder type, etc., and can be appropriately selected depending on the purpose and use. Examples 1 to 2 and Comparative Examples 1 to 3 670 parts of xylene and 10 parts of di-tert-butyl peroxide were charged into a flask equipped with a thermometer, a stirrer, and a reflux condenser, and heated to 120°C. A liquid mixture consisting of the monomer mixture shown in each of the Examples and Comparative Examples and 15 parts of azobisisobutyronitrile was added dropwise over 6 hours. Another 15 hours 120
Each resin solution was obtained by maintaining the temperature at °C. Supervecamine L- was added to each resin solution obtained.
117-60 (butylated melamine resin; manufactured by Dainippon Ink and Chemicals Co., Ltd.) and Epiclon 1050 (bisphenol type epoxy resin; manufactured by Dainippon Ink and Chemicals)
Co., Ltd.) at a ratio of 70/20/10 (solid ratio).
Mixed with 50% PWC using Taipeke R-580 (rutile titanium oxide, manufactured by Ishihara Sangyo Co., Ltd.) and heated to 160℃ after painting.
I baked it for 20 minutes. Table 1 shows the physical properties of the resulting coating film. Additionally, an outdoor exposure test of the paint film was conducted in Miyazaki Prefecture. The results are shown in FIG.

【table】 [Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between exposure time and gloss retention rate in an outdoor exposure test of each cured coating film of Examples 1 to 2 and Comparative Examples 1 to 3. ...Example 1, ...Example 2, ...Comparative example 3, ...Comparative example 2, ...Comparative example 1

Claims (1)

[Claims] 1 (A) General formula (In the formula, R ₁ is -H or -CH ₃ , R ₂ is -H or -OH, R ₃ is -H, -OH, -OR ₄ or [Formula] R ₄ is an alkyl group having 1 to 18 carbon atoms) ) Monomer represented by 0.05 to 10% by weight (B) At least one monomer selected from styrene, acrylonitrile, and alkyl methacrylate 20 to 99.95% by weight (C) Obtained from 0 to 79.95% by weight of other copolymerizable monomers A resin composition for paint containing a copolymer.