JPS6253550B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a copolymer liquid for coatings with a high solid content of 60% by weight or more, which can be crosslinked and cured at room temperature or by baking by incorporating a crosslinking agent capable of reacting with hydroxyl groups. In the paint industry, high solid content paints and water-soluble paints that reduce solvent volatilization into the atmosphere, as well as powder paints that do not volatilize solvents, are becoming more important as low-pollution or resource-saving paints. It is increasing. on the other hand,
In the painting industry, we also manufacture home appliances such as refrigerators and washing machines, steel products such as steel furniture, guardrails, colored corrugated iron, and gates, building materials products such as slate tiles, agricultural machinery such as combines and tractors, and general metal machinery products. Since a large amount of paint is used in painting industrial products that are produced in large quantities, a large amount of solvent is emitted within a limited area, and reducing solvent consumption is also important from an environmental hygiene perspective. It is becoming. However, in reality,
Powder paints and water-soluble paints are difficult to repaint or change colors, have low pigment concentration, emit a peculiar odor, have poor stain resistance, poor corrosion resistance, require new equipment, etc. For this reason, high solids paints that have the same performance as conventional solvent-based paints but can reduce the amount of solvent emitted are used in conventional painting equipment. It is attracting attention because the drying equipment can be used as is. The present inventors conducted various research on high solid content paints and found that the paint film had a low viscosity despite having a high solid content, and also had a characteristic performance in terms of the performance of the paint film obtained by disposing a crosslinking agent. We have discovered a copolymer liquid for coatings with a high solid content that exhibits the above properties, and have completed the present invention. That is, the present invention provides (A) general formula

[Formula] (However, R ₁ and R ₂ represent an alkyl group having 1 to 12 carbon atoms.) 10 to 40% by weight of a copolymerizable unsaturated monomer, (B) 10 to 50% by weight of styrene, (C)
Hydroxyl group-containing vinyl monomer 5-40% by weight and (D) other copolymerizable vinyl monomer 0-75% by weight
A hydroxyl group-containing copolymer having a number average molecular weight of 500 to 4000, obtained by polymerizing a monomer composition with a monomer ratio (A)/(B)≦1, in the presence or absence of a solvent, as a solid content. The present invention provides a copolymer liquid for high solids coatings containing 60% by weight or more. The copolymerizable unsaturated monomer (A) represented by the above general formula, which is a raw material for forming the solid content of the copolymer liquid for high solids coatings of the present invention, is maleic acid or fumaric acid having 1 to 12 carbon atoms. It is a dialkyl ester obtained by esterification with a linear or branched aliphatic monohydric alcohol, typically dimethyl, diethyl, di-n of maleic acid or fumaric acid.
-propyl, di-iso-propyl, di-n-butyl, di-iso-butyl, di-tert-butyl or di(2-ethylhexyl) ester. As the hydroxyl group-containing vinyl monomer (C), 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, N-methylolated acrylamide, hydroxyethyl vinyl ether, or any of these hydroxyl groups A hydroxyl group-containing unsaturated polymerizable compound obtained by adding a dicarboxylic anhydride to a vinyl monomer and then adding a monoglycidyl compound such as "Cardilla E" (manufactured by Shell Co., Ltd.) can be used. Other copolymerizable monomers (D) that can be copolymerized with monomers (A), (B), and (C) as listed above;
Representative examples include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and n-butyl (meth)acrylate.
Acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate,
Lauryl (meth)acrylate, cyclohexyl (meth)acrylate or benzyl (meth)acrylate
(meth)acrylic acid esters such as acrylates, unsaturated carboxylic acids such as (meth)acrylic acid, crotonic acid or itaconic acid, or (meth)acrylonitrile, (meth)acrylamide, vinyl acetate, vinyl propionate or chloride. In addition to these, there are also alkyd resins having polymerizable double bonds, oil-free alkyd resins, acrylic resins, etc., the above-mentioned unsaturated monomers (A), styrene (B), and hydroxyl group-containing vinyls. Any substance, regardless of whether it is a monomer, oligomer or polymer, can be used as a substance having the same effect as the vinyl monomer (D) as long as it is copolymerizable with the monomer (C). The proportion of each of these monomers used is such that the copolymerizable unsaturated monomer (A) represented by the above general formula is
10-40% by weight (hereinafter abbreviated as %), preferably 10
~35%; if it is less than 10%, it is difficult to obtain a copolymer liquid with a low molecular weight and high solid content, and the weather resistance of the resulting coating film is also poor; on the other hand, if it exceeds 40%, the monomer becomes reactive. Since it is inferior, the presence of free monomer increases, and polymerization cannot be completed completely, resulting in a decrease in stain resistance and corrosion resistance of the resulting coating film. Styrene (B)
is 10-50%, preferably 15-45%, and 10%
If it is less than 50%, the chemical resistance, water resistance, and gloss of the coating film will be poor, and if it is more than 50%, the weather resistance and flexibility will be deteriorated. The content of the hydroxyl group-containing vinyl monomer (C) is 5 to 40%, preferably 10 to 40%, and if it is less than 5%, the crosslink density will be low when crosslinked and cured, resulting in a decrease in the hardness and solvent resistance of the coating film. If it exceeds 40%, the crosslinking density will be too high and it will become rigid and inflexible. The amount of other copolymerizable monomers (D) to be used is suitably within the range of 3 to 75%, preferably 5 to 60%. When adding a carboxyl group-containing monomer as component (D), it is preferable that its proportion be 30 mol% or less of the hydroxyl group-containing vinyl monomer (C), and furthermore, the resin having double bonds in the molecule should be added as component (D). If used as
It is desirable to keep it up to 20%. In the present invention, the above (A), (B) and (C) or (A),
The molar ratio (A)/(B)≦
1. Preferably, it is necessary to set the range of (A)/(B)<1, and when (A)/(B)>1, component (A) which is not homopolymerizable exists as a free monomer, and crosslinking occurs. It has a negative effect on the stain resistance and corrosion resistance of the cured coating film. In order to obtain a copolymer liquid for high solids coatings with the above monomer composition that has low viscosity and exhibits characteristics in coating film performance, it is necessary to further combine the above (A), (B) and (C) or (A). , (B), (C) and (D) components are copolymerized in the presence or absence of a solvent to have a number average molecular weight in the range of 500 to 4000,
Furthermore, it is necessary that the solid content concentration is 60% by weight or more. In this case, free monomers are not present in substantial amounts in the resulting high solid content coating copolymer liquid, and each monomer is consumed as a component of a copolymer having a molecular weight of 500 to 4,000. As a typical method for producing a copolymer liquid having a number average molecular weight and solid content concentration within the above range,
Copolymerizing the monomer of component (A) with the monomers of component (B) and (C), respectively, or the monomers of component (B), (C), and (D) individually or as a mixture, Component (C) is added to a monomer composition consisting of both components (A) and (B), or (C) and
Examples include a method of copolymerizing while adding both components (D). In the present invention, without using a solvent,
From (A), (B) and (C) or (A), (B), (C) and (D) components, solid content with number average molecular weight in the range of 500 to 4000 100
% liquid copolymer can be produced. Preferably, a copolymer solution with a solids content of 60-95% is obtained in the presence of a solvent. Various solvents used in ordinary solution polymerization methods can be used as the solvent for producing the copolymer, such as aromatic solvents such as toluene and xylene, ester solvents such as ethyl acetate and butyl acetate, methanol, butanol, etc. alcohol solvents, and ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone. In addition, poor solvents such as mineral spirits can also be used as long as they do not cause a decrease in solubility. In addition, as a polymerization initiator, peroxides such as benzoyl peroxide and di-t-butyl peroxide, and azo compounds such as azobisisobutyronitrile are used, and it is also possible to polymerize in a redox system. Furthermore, a chain transfer agent such as lauryl mercaptan or octyl thioglycolate may be used if necessary. Reaction temperature is room temperature ~ 200℃
℃, and the polymerization may normally be carried out for 2 to 30 hours. By disposing the copolymer liquid of the present invention a crosslinking agent capable of reacting with hydroxyl groups, a cured coating film having excellent various properties can be obtained by baking at room temperature or baking. Preferred crosslinking agents include, for example, amino resins,
Examples include polyisocyanate. Examples of the amino resin include a condensate obtained by reacting one or a mixture of two or more amino compounds such as melamine, urea, and benzoguanamine with formaldehyde, and an etherified product obtained by reacting the condensate with a lower alcohol. In addition, polyisocyanates include those obtained by adding diisocyanates such as tolylene diisocyanate, xylene diisocyanate, and hexamethylene diisocyanate to the hydroxyl groups of polyhydric alcohols such as glycerin, trimethylolpropane, and pentaerythritol, and polymers of diisocyanates. Furthermore, blocked isocyanates in which the isocyanate groups of these polyisocyanate compounds are blocked with a blocking agent such as phenol, oxime, or methanol can also be used. The ratio of the copolymer liquid for coating material of the present invention and the crosslinking agent used is 50 to 95 parts by weight: 5 to 50 parts by weight (assuming the total amount is 100 parts by weight) in terms of solid content ratio. Furthermore, other resins may be appropriately added to the coating copolymer liquid of the present invention in order to improve the coating performance. Typically, bisphenol A (methyl) glycidyl ether type, novolac poly(methyl) glycidyl ether type,
Various epoxy resins include (methyl)glycidyl ether type of polyhydric alcohol, (methyl)glycidyl ester type of polybasic acid, and peracetic acid type obtained by oxidizing intramolecular double bonds with peracetic acid. The present invention will be explained below by giving examples, but the present invention is not limited by these. In the examples, parts represent parts by weight. Production example (production of oil-free alkyd for modification) In a reaction vessel equipped with a thermometer, stirrer, and nitrogen gas blowing tube, 545 parts of isophthalic acid, 248 parts of adipic acid, 362 parts of neopentyl glycol, 276 parts of trimethylolpropane, and Add 15 parts of maleic anhydride,
While removing water generated under nitrogen gas atmosphere
Reacted at 150°C to 220°C for 5 hours and then at 220°C for 5 hours to produce an oil-free alkyd resin with a hydroxyl value of 135 Hmg/g (units will be omitted hereafter) and an acid value of 8KOHmg/g (units will be omitted hereafter). I got it. It was diluted with a solvent with a weight ratio of toluene/butyl acetate = 50/50 to obtain a nonvolatile content of 60.5%, viscosity O-P, and acid value.
4.7, an oil-free alkyd resin solution having a color number (Gardner) of 1 or less was obtained. Example 1 N-butanol 110 was added to a four-necked flask equipped with a thermometer, reflux condenser, nitrogen gas inlet, and stirrer.
1 part, 310 parts of "Swazol 1000" [aromatic hydrocarbon solvent manufactured by Maruzen Oil Co., Ltd.], 300 parts of dimethyl fumarate, and 3 parts of ditertiary butyl peroxide (hereinafter abbreviated as DTBPO) were charged, and the mixture was heated at 120°C. When the temperature reached 120°C, 300 parts of styrene, 190 parts of ethyl acrylate, 200 parts of 2-hydroxyethyl methacrylate, 10 parts of methacrylic acid, and tert-butyl peroxyoctaate (hereinafter referred to as
A formulation consisting of 50 parts of azobisisobutyronitrile (hereinafter abbreviated as AIBN), 2 parts of tertiary butyl peroxybenzoate (hereinafter abbreviated as TBPB) and 130 parts of "Swasol 1000" was prepared. Dropped in 8 hours and reacted for another 6 hours to obtain a solid content of 65.8%, viscosity (Gardner viscosity) R-S,
A transparent resin solution with a number average molecular weight of 3200 and an acid value of 6.1 was obtained. The structural formula of the resin obtained in this example is as follows. Example 2 In a flask similar to Example 1, n-butanol was added.
129 parts, 201 parts of "Swazol 1000", 250 parts of dibutyl fumarate and 2 parts of DTBPO were charged, the temperature was raised to 125℃, and when it reached 125℃, 300 parts of styrene, 50 parts of dibutyl fumarate, and 190 parts of methyl acrylate were added.
Part, 2-hydroxyethyl methacrylate 200
parts, 10 parts of methacrylic acid, 100 parts of "Swazol 1000"
A mixture of 60 parts of TBPO, 13 parts of AIBN, 3 parts of TBPB, and 10 parts of octyl thioglycolate was added dropwise over 8 hours and reacted for an additional 6 hours to give a solid content of 71.2%.
A transparent resin solution with a viscosity T, a number average molecular weight of 2400, and an acid value of 6.5 was obtained. The structural formula of the resin obtained in this example is as follows. Example 3 Into a flask similar to Example 1, 166 parts of the oil-free alkyd resin solution shown in the production example, 109 parts of n-butanol, 155 parts of "Swazol 1000", 270 parts of dimethyl fumarate, and 2 parts of DTBPO were charged.
℃, and when it reached 125℃, 315 parts of styrene,
171 parts of ethyl acrylate, 135 parts of 2-hydroxyethyl methacrylate, 9 parts of methacrylic acid, 100 parts of "Swazol 1000", 10 parts of AIBN, 50 parts of TBPO,
A mixture consisting of 2 parts of TBPB and 5 parts of octyl thioglycolate was dropped over 8 hours and reacted for an additional 6 hours to obtain a solid content of 71.5%, viscosity W, and number average molecular weight.
2900, a transparent resin solution with an acid value of 5.8 was obtained. The structural formula of the resin obtained in this example is as follows. Comparative Example 1 In a flask similar to Example 1, n-butanol was added.
110 parts of "Swazol 1000" and 3 parts of DTBPO were charged, the temperature was raised to 120℃, and when it reached 120℃, 300 parts of styrene, 300 parts of methyl acrylate, 190 parts of ethyl acrylate, and 200 parts of 2-hydroxyethyl methacrylate were added. , 10 parts of methacrylic acid, TBPO50
division, AIBN10 division, TBPB division 2 and “Swazol
A formulation consisting of 130 parts of ``1000'' was added dropwise over 8 hours.
After further reaction for 6 hours, the solid content was 66.0% and the viscosity was Z <sub>2</sub> -
A transparent resin solution with Z <sub>3</sub> , number average molecular weight of 5000, and acid value of 6.3 was obtained. The oil-free alkyd resin part in the resin obtained in this example is omitted, and the structural formula of the part derived exclusively from the vinyl monomer is shown as follows. Comparative Example 2 In a flask similar to Example 1, n-butanol was added.
129 parts of Swasol 1000, 201 parts of DTBPO, and 2 parts of DTBPO were heated to 125°C, and when it reached 125°C, 300 parts of styrene, 300 parts of butyl methacrylate, 190 parts of methyl acrylate, and 200 parts of 2-hydroxyethyl methacrylate were added. , 10 parts of methacrylic acid, 100 parts of "Swazole 1000", 60 parts of TBPO, 13 parts of AIBN,
A mixture consisting of 3 parts of TBPB and 10 parts of octyl thioglycolate was added dropwise over 8 hours and reacted for an additional 6 hours to give a solid content of 71.5%, viscosity Z <sub>5</sub> , number average molecular weight 4200,
A clear resin solution with an acid value of 6.1 was obtained. The structural formula of the resin obtained in this example is as follows. Comparative Example 3 In a flask similar to Example 1, 166 parts of the oil-free alkyd resin solution shown in the Production Example, 109 parts of n-butanol, 155 parts of "Swazol 1000" and
Charge 2 parts of DTBPO, raise the temperature to 125°C, and when it reaches 125°C, 270 parts of methyl methacrylate, 315 parts of styrene, 171 parts of ethyl acrylate, 135 parts of 2-hydroxyethyl methacrylate, 9 parts of methacrylic acid, "Swazol 1000" 100 copies, AIBN 10 copies,
50 parts of TBPO, 2 parts of TBPB, and 5 parts of octyl thioglycolate were added dropwise over 8 hours and reacted for an additional 6 hours to obtain a solid content of 71.4%, a viscosity of Z <sub>6</sub> - Z <sub>7</sub> , and a number average molecular weight.
A clear resin solution with an acid value of 4800 and an acid value of 5.6 was obtained. The oil-free alkyd resin portion in the resin obtained in this example is omitted, and the structural formula of the portion derived exclusively from the vinyl monomer is as follows. The application test results of the copolymers obtained in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in the following table. During application tests, the obtained copolymer and "Supervecamine L"
``-109-60'' melamine resin manufactured by Dainippon Ink and Chemicals Co., Ltd., ``Epicron 1050'' (epoxy resin manufactured by the same company), and ``Tipeque R-580'' [rutile-type titanium oxide manufactured by Ishihara Sangyo Co., Ltd.] The solid content weight ratio is 70:
After blending at 20:10:100 and kneading with three rolls, xylene/"Swazol 1000"/n-butanol/
"Methoacetate" [manufactured by Dainippon Kasei Co., Ltd.] 3-methoxybutyl acetate = diluted with a mixed solvent of 40/30/20/10 weight ratio for 20 seconds in a food cup #4, adjusted, and treated with zinc phosphate. It was spray-painted to a film thickness of approximately 35 μm and baked at 150°C for 20 minutes.

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Claims (1)

[Claims] 1 (A) General formula [However, R ₁ and R ₂ represent an alkyl group having 1 to 12 carbon atoms. ] 10 to 40% by weight of a copolymerizable unsaturated monomer represented by (B) 10 to 50% by weight of styrene, (C) 5 to 40% by weight of a hydroxyl group-containing vinyl monomer, and (D) other copolymerizable monomers. 3~ of polymerizable monomers
A hydroxyl group-containing copolymer having a number average molecular weight of 500 to 4000 obtained by polymerizing a monomer composition consisting of 75% by weight and having a molar ratio (A)/(B)≦1 in the presence or absence of a solvent. A copolymer liquid for high solids paints containing 60% by weight or more of copolymer.