JPH036209A - Coating copolymer, its production, and coating composition - Google Patents

Abstract

PURPOSE:To obtain a coating copolymer excellent in weathering and chemical resistances, pigment dispersion and luster by copolymerizing a specified ethylenically unsaturated compound with another ethylenically unsaturated monomer copolymerizable therewith in a specified ratio. CONSTITUTION:10-90wt.% ethylenically unsaturated compound of the formula (wherein R is 1-18C alkylene; R' is H or lower alkyl) is copolymerized with 90-10wt.% another ethylenically unsaturated monomer copolymerizable therewith, e.g. alkyl acrylate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a coating copolymer having a fluorine atom in its molecular structure, a method for producing the same, and a coating composition.

[Conventional technology]

In recent years, there has been a strong demand in the paint industry for maintenance-free paint films, that is, paints with high weather resistance from the viewpoint of resource and energy conservation. In order to obtain a highly weather resistant paint, a highly weather resistant pigment and a highly weather resistant resin are required.

Fluoroolefin polymers, typified by Teflon, have long been known as highly weather-resistant resins. However, fluoroolefin polymers are rarely used as paints because they do not dissolve in organic solvents such as toluene and xylene. In recent years, two types of solvent-soluble fluororesins have been proposed as paints. One type is a copolymer containing fluoroolefin, hydroxya, alkyl vinyl ether, alkyl vinyl ether, and cyclohexyl vinyl ether as essential components (Japanese Patent Publication No. 60-21686). The other type is a copolymer of fluoroalkyl acrylate or fluoroalkyl methacrylate and other monomers copolymerizable with them, such as acrylic ester, methacrylic ester, and styrene (Japanese Patent Publication No. 63-28472). ).

[Problem to be solved by the invention]

Such solvent-soluble fluororesins are used as coating resins, but they have many problems. That is, the former copolymer of fluoroolefin and vinyl ether was inferior in pigment dispersibility and gloss, and could not be used in fields requiring good appearance.

In addition, for the latter fluoroalkyl acrylate or fluoroalkyl methacrylate copolymers, it is possible to improve pigment dispersibility and gloss by changing the copolymerized monomer, but the important weather resistance is the acrylic resin. There is no point in copolymerizing fluoroalkyl acrylate or fluoroalkyl methacrylate.

Therefore, an object of the present invention is to provide a coating copolymer having excellent weather resistance and chemical resistance, and excellent pigment dispersibility and gloss comparable to acrylic resin, a method for producing the same, and a coating composition. do.

[Means to solve the problem]

The present invention provides an ethylenically unsaturated compound represented by (A)-More (I): [wherein R represents an alkylene group having 1 to 18 carbon atoms, and R' represents hydrogen or a lower alkyl group] A coating characterized by blending and copolymerizing 10 to 90% by weight of a compound having a bond and (B) 90 to 10% by weight of another ethylenically unsaturated monomer copolymerizable with the component (A). The present invention relates to a method for producing a coating copolymer, a coating copolymer obtained thereby, and a coating composition containing the coating copolymer as an essential component.

The compound having an ethylenically unsaturated bond as the component (A) used in the production of the coating copolymer of the present invention has the general formula (I
), the nitrogen atom of the tetrafluorophthalimide group is linked to an alkylene group having 1 to 1 carbon atoms to form fluorophthalimide, N-(2-methacryloyloxymethyl)- Tetrafluorophthalimide, N-(2-
Examples include acryloyloxyethyl)-tetrafluorophthalimide, N-(2-methacryloyloxyethyl)-tetrafluorophthalimide, and the like.

The monomer represented by general formula (1), which is component (A), is produced by a known method. For example, the general formula (II[) is obtained by reacting tetrafluorophthalic anhydride represented by -Momona (n) with ethanolamine. Here, R' represents hydrogen or a lower alkyl group, preferably hydrogen or a methyl group.

As the monomer represented by the general formula (I), N-(2
-N- represented by -acryloyloxymethyl)-tetra
(2-Hydroxyethyl)-tetrafluorophthalimide is synthesized. Furthermore, N represented by -monka (III)
N-(2-methacroyloxyethyl)-tetrafluorophthalimide can be obtained by reacting -(2-hydroxyethyl)-tetrafluorophthalimide with methacrylic acid.

The monomer represented by general formula (I), which is component (A), is
It is blended in an amount of 10 to 90% by weight, preferably 10 to 50% by weight. If the monomer content is less than 10% by weight, weather resistance and chemical resistance will deteriorate. If it exceeds 90% by weight, the number of fluorine atoms in the resin will increase, resulting in poor solvent solubility.

The component (B) used in the production of the coating copolymer of the present invention is:
It is another ethylenically unsaturated monomer copolymerizable with the above component (A). Component (B) includes acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, butyl acrylate, isopropyl acrylate, and 2-ethylhexyl acrylate, similar alkyl esters of methacrylic acid, styrene or vinyltoluene, α- Substituted styrene such as methylstyrene and chlorostyrene, acrylonitrile, metacyclonitrile, vinyl chloride, vinegar
Vinyl, maleic acid dialkyl esters, etc. can be used, and furthermore, 2-hydroxyethyl acrylate,
Acrylic acid hydroxyalkyl esters such as 2-hydroxypropyl acrylate and 2-hydroxybutyl acrylate, similar hydroxyalkyl esters of methacrylic acid, monoacrylic esters or monomethacrylic esters of polyhydric alcohols such as glycerin, trimethylolpropane, etc. , N-methylol acrylamide, N-methylol methacrylamide, or an alkyl ether thereof, or a polymerizable monomer having a hydroxyl group can be used. In addition, if necessary, unsaturated amides such as acrylamide and methacrylamide, polymerizable monomers containing oxirane groups such as glycidyl methacrylate and glycidyl acrylate, α such as acrylic acid, methacrylic acid, and maleic acid monoalkyl ester, β-unsaturated carboxylic acid and the like can be used.

The ethylenically unsaturated monomer (B) component is blended in an amount of 90 to 10% by weight, preferably 50 to 90% by weight. If it is less than 10% by weight, the number of fluorine atoms in the resin increases, resulting in poor solvent solubility. If it exceeds 9ON%, the ratio of the monomer having a tetrafluorophthalimide group, which is component (A), will be low, resulting in insufficient weather resistance.

There are no particular restrictions on the type and amount of the monomer used as component (B), but if the polymerizable monomer containing an unsaturated amide and/or oxirane group is too large, the water resistance of the coating film may decrease. or the reaction solvent tends to be limited.
It is preferable to use it in an amount of 30% by weight or less based on the total amount of components (A) and (B). If the amount of α,β-unsaturated carboxylic acid is too large, the water resistance of the coating film tends to decrease, so it is preferably used in an amount of 10% by weight or less.

The method of copolymerizing component (A) and component (B) is not particularly limited, and toluene, xylene, methyl isobutyl ketone, ethyl acetate, butyl acetate, cellosolve acetate,
Butyl cellosolve, 1-butanol, 2-butanol,
Organic solvents such as 1-propertool and 2-propertool are used as reaction solvents, and peroxides such as benzoyl peroxide, di-tert-butyl peroxide, and cumene hydroperoxide, and azobisisobutyronitrile and the like are used as polymerization catalysts. Preferably 0.1 to 10 of the azobis compound etc. based on the total monomers.
% by weight, more preferably 1 to 5% by weight, 50 to 20
This can be carried out by heating the reaction at 0°C for 1 to 10 hours. The polymerization catalyst is appropriately selected in order to obtain the polymerization temperature, the desired molecular weight and molecular weight distribution, and to complete the polymerization, that is, to reduce the residual amount. For the above purpose, two or more types of polymerization initiators may be used in combination.

The coating copolymer obtained according to the present invention is used as a resin component of a coating composition. In this case, other acrylic resins may be used in combination. When used as a coating composition, for example organic? It can be made into a lacquer paint by dissolving it in 8 agents. Further, it can be used in combination with a curing agent such as an amino resin such as a melamine resin, an isocyanate prepolymer, etc. to form a curable paint. In this case, the hydroxyl value of the copolymer is a factor that influences the performance of the cured film. The hydroxyl value can be adjusted by adjusting the amount of the monomer having a hydroxyl group in component (B). Furthermore, inorganic pigments such as titanium white, cadmium yellow, and carbon black, and organic pigments such as phthalocyanine and azo pigments can be added as necessary. Additionally, additives such as antioxidants and pigment dispersants may be used as necessary. It is preferable that the pigment be thoroughly kneaded with the copolymer before use. The coating composition obtained as described above is particularly suitable for coating wood, metal, slate, tiles, automobiles, etc. that require weather resistance.

〔Example〕

Next, the present invention will be further explained with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In addition, "parts" and "1%" in the examples are "parts by weight" and "1%", respectively.
% by weight.

Example 1 300 g of xylene was placed in a flask equipped with a stirrer, a reflux condenser, and a thermometer, and after the temperature was raised to 80°C, the following monomer mixture was added dropwise over 2 hours.

N-(2-Methacroyloxyethyl)-tetrafluorophthalimide 100g Methyl methacrylate
95g butyl methacrylate
250g 2-hydroxyethyl methacrylate 50g methacrylic acid
5g Azobisisobutyronitrile 5g
After the addition was completed, the mixture was kept warm for 1 hour, and a solution prepared by dissolving 1 g of butyl perbenzoate in 50 g of xylene was added dropwise over 30 minutes. After the dropwise addition was completed, the temperature was raised to 120'C, and the temperature was maintained for 1 hour to complete the polymerization reaction. After cooling, xylene was further added to adjust the heating residue to 50%. A transparent resin (copolymer for coating) having the following properties was obtained: resin viscosity Z, acid value 3.1, and color number 1 or less.

Examples 2 to 5 Resins were synthesized by carrying out the same operations as in Example 1, except that the composition of the monomer mixture to be added dropwise was changed as shown in Table 1. The properties of the obtained resin are shown in Table 1.

Comparative Examples 1 to 4 A resin was synthesized by carrying out the same operation as in Example 1, except that the composition of the monomer mixture solution to be added dropwise was changed as shown in Table 2. In Comparative Examples 3 and 4, for comparison, IF (IH, 2H, 2H-hebutadecafluorodecyl acrylate (manufactured by Osaka Organic Chemical Industries, trade name: Viscoat 17F) was used as the fluoroalkyl acrylate.

Solutions of the coating copolymers obtained in Examples 1 to 5 and Comparative Examples 1 to 4 and Lumiflon 200 (manufactured by Asahi Glass Co., Ltd., 50% of a copolymer of trifluorochloroethylene and vinyl ether)
% xylene solution) (Comparative Example 5), the following test was conducted.

To 60 parts of each solution, 40 parts of Titanium White Thai Bake CR95 (manufactured by Ishihara Sangyo ■) was added, and the titanium white was dispersed using a sand mill. After dispersion, 60 parts of each solution was added to prepare an enamel containing 40% P, W, and C. Before coating, an isocyanate prepolymer (Coronate EH, manufactured by Nippon Polyurethane ■) was added so that the hydroxyl groups and isocyanate groups of each copolymer were equimolar. moreover,
After adjusting the viscosity with thinner, spray paint on Bonderite #144 treated steel plate (manufactured by Nippon Test Panel) to a film thickness of 30.
It was coated to a thickness of μm. The coated plates were cured in an atmosphere of 23 parts at 3°C and 70% relative humidity, and the performance of the coating films was evaluated. The results are shown in Table 3.

(1) Initial Gloss The 60 degree specular reflectance of the prepared test plate was measured using a gloss needle.

(2) Accelerated weathering test
After exposing to ultraviolet light for a predetermined time under cycle conditions of 4 hours at 50°C and 4 hours at 50°C with condensation, the 60 degree specular reflectance was measured, and the gloss retention was calculated using the following formula: The rate was calculated.

(3) Chemical resistance The prepared test plate was immersed in a 5% sulfuric acid solution and a 5% sodium hydroxide solution, and left for 240 hours.
Visual observation was made for blistering and discoloration.

Regarding chemical resistance, it was evaluated according to the following criteria:
No abnormality in the coating film ×... Abnormality occurred in the coating film (4) Pigment dispersibility Mix 50 parts of each solution (solid content) and 3 parts of carbon black, knead with three rolls, and check the particle size with a particle gauge. is 10μm
The mixture was kneaded until it became as follows. Subsequently, the prepared paint was allowed to stand at room temperature for 7 days, and the separation (sedimentation) property of the pigment was examined.

Pigment dispersibility was evaluated using the following criteria: ○...
・No separation×・・・Separated Examples 6 to 8 and Comparative Examples 6 to 7 A solution of the coating copolymer was reacted in the same manner as in Example 1 except that the formulations shown in Table 4 were used. I got it. The properties of the resulting coating copolymer are shown in Table 4.

Examples 6-8, Comparative Examples 6-7 and the above Lumiflon 20
0 was used to test so-called lacquer paints without hardeners. Each resin was diluted with thinner and evaluated in the same manner as in Examples 1 to 5. [Effects of the Invention] The coating copolymer and coating composition of the present invention have excellent weather resistance,
Excellent chemical resistance, pigment dispersibility and gloss.

Therefore, the coating composition of the present invention is useful as a lacquer paint or a curable paint for coating various materials.

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Claims (1)

[Claims] 1. (A) General formula (I) ▲ Numerical formulas, chemical formulas, tables, etc. are included ▼ (I) [In the formula, R represents an alkylene group having 1 to 18 carbon atoms, and R' is 10 to 90% by weight of a compound having an ethylenically unsaturated bond represented by hydrogen or a lower alkyl group and (B) 90 to 10% of other ethylenically unsaturated monomers copolymerizable with the above component (A). 1. A method for producing a coating copolymer, which comprises blending % by weight and copolymerizing. 2. A coating copolymer obtained by the production method according to claim 1. 3. A coating composition containing the coating copolymer according to claim 2 as an essential component. 4. A coating composition comprising the coating copolymer according to claim 2 and a curing agent. 5. The coating composition according to claim 4, wherein the coating copolymer contains a hydroxyl group. 6. The coating composition according to claim 4 or 5, wherein the curing agent is an amino resin or an isocyanate prepolymer.