JPH0226659B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition for lacquer that has excellent pigment dispersibility and coating film weather resistance. In recent years, there has been a strong demand in the paint industry for maintenance-free paint films, that is, lacquer paints with high weather resistance, from the viewpoint of saving resources and energy. Conventionally, acrylic resins have been commonly used for applications that require weather resistance, but there is a desire for even higher levels of resins. In addition, acrylic resin is used as a resin for lacquering.
In general, it has poor compatibility with pigments that have high oil absorption,
In particular, pigment dispersion of pigments such as carbon black is extremely poor, and disadvantages include that it takes a long time for uniform dispersion and that pigment separation occurs during storage. Therefore, in order to improve pigment dispersibility, a method of synthesizing acrylic resin in the presence of an alkyd resin having unsaturated carbon-carbon double bonds has been reported and carried out, but this method does not interfere with the original performance of acrylic resin. In comparison, it has the problem of impairing weather resistance, chemical resistance, etc. On the other hand, copolymers containing fluoroolefin, hydroxyalkyl vinyl ether, alkyl vinyl ether, and cyclohexyl vinyl ether as essential components are known, and these have excellent weather resistance and are considered for use in paints, but pigment dispersibility It has the problem of being inferior. The present invention solves these problems and provides a resin composition for lacquer that further improves the weather resistance of an acrylic resin and has excellent pigment dispersibility. That is, the present invention comprises: (A) 0.001 to 0.055 mole of reactive carbon-carbon double bonds per 100 g of resin and 0.5 to 50% by weight of a fluorine-containing resin having an alkoxy group or a cyclohexyloxy group; (B) methyl methacrylate 30 ~50% by weight and (C) 69.5~0% by weight of other copolymerizable unsaturated monomers so that the total amount is 100% by weight, and the resulting graft copolymer ()70~
99% by weight of cellulose ester and 30-1% by weight of cellulose ester. The fluorine-containing resin, component (A) of the present invention, contains reactive carbon-carbon double bonds per 100 g of the resin.
It has 0.001 to 0.055 mol, preferably 0.005 to 0.031 mol. If it is less than 0.001 mol, graft polymerization becomes difficult when polymerizing with component (B), and if it exceeds 0.055 mol, gelation tends to occur during polymerization. Further, the fluorine-containing resin has an alkoxy group or a cyclohexyloxy group. Thereby, it can be made soluble in organic solvents such as xylene, toluene, butyl acetate, and methyl isobutyl ketone. Furthermore, by containing fluorine,
The paint film using the graft copolymer obtained by the present invention has excellent weather resistance. The fluorine-containing resin of component (A) has a molecular weight of approximately
1000 to 200000 is preferred, especially about
10,000 to 100,000 is preferred. If the molecular weight is too low, weather resistance and chemical resistance tend to decrease.
If it is too high, when component (B) is polymerized in the presence of component (A), gelation tends to occur easily. The fluorine-containing resin, which is component (A), is a copolymer (a) having a hydroxyl group with alpha and beta acids such as maleic anhydride, acrylic acid, methacrylic acid, acrylic anhydride, methacrylic anhydride, and their acid chlorides. -Can be obtained by reacting an unsaturated carboxylic acid or its hydroxyl group with a reactive derivative. In this case, 0.001 to 0.055 mol of the α,β-unsaturated carboxylic acid or its hydroxyl group-reactive derivative is reacted with respect to 100 g of the hydroxyl group-containing copolymer (a). The above copolymer (a) includes fluoroolefins such as chlorotrifluoroethylene, trifluoroethylene, and tetrafluoroethylene; hydroxyalkyl vinyl ethers and ethyl vinyl ethers such as hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, and hydroxyhexyl vinyl ether; It is a copolymer obtained by copolymerizing alkyl vinyl ether or cyclohexyl vinyl ether, such as propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, etc., in which the hydrogen of the alkyl group or vinyl group is replaced with fluorine. It may contain ethylene, propylene, isobutylene, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl n-butyrate, methyl methacrylate, etc. as a copolymerization component. The fluoroolefin is preferably used in copolymer (a) in an amount of 40 to 60 mol %, and the hydroxyalkyl vinyl ether is preferably used in an amount of 0.57 to 100, particularly 3 to 70, hydroxyl groups. If the amount of fluoroolefin is too small, the effect of improving weather resistance tends to decrease, and it is difficult to introduce a large amount in terms of production. The copolymer (a) has a hydroxyl value of 0.57 to 100, preferably 3 to 70. If the hydroxyl value is less than 0.57, it will be difficult for α,β-unsaturated carboxylic acid or its hydroxyl-reactive derivative to react completely;
If the amount exceeds 1, the amount of hydroxyalkyl vinyl ether used increases, and solubility in organic solvents tends to be limited. From the viewpoint of solubility in organic solvents, hydroxyalkyl vinyl ether is preferably used in an amount of 15 mol% or less. Moreover, it is preferable to use cyclohexyl vinyl ether and alkyl vinyl ether in a total amount of 5 to 60 mol % in the copolymer (a). If the amount of cyclohexyl vinyl ether and alkyl vinyl ether is too small, the copolymer (a) will be difficult to dissolve in an organic solvent, and if it is too large, the amount of fluoroolefin or hydroxyalkyl vinyl ether used will be reduced. Moreover, it is preferable from the viewpoint of characteristics that cyclohexyl vinyl ether and alkyl vinyl ether are used in an amount of 5 to 45 mol %, respectively. Other components are preferably used in copolymer (a) in an amount of 30 mol% or less. Component (C) includes ethyl acrylate, butyl acrylate, isopropyl acrylate, 2-
Alkyl acrylates such as ethylhexyl acrylate, similar alkyl methacrylates, substituted styrenes such as styrene or vinyltoluene, α-methylstyrene, chlorostyrene, acrylonitrile, methacrylonitrile, vinyl chloride, vinyl acetate, maleic acid dialkyl esters may be used. Furthermore, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate, similar hydroxyalkyl methacrylates, monoacrylates or monoacrylates of polyhydric alcohols such as glycerin, trimethylolpropane, etc. Ethylenically unsaturated monomers having a hydroxyl group such as methacrylate, N-methylol acrylamide, and N-methylol methacrylamide can be used. In addition, if necessary, unsaturated amides such as acrylamide and methacrylamide, unsaturated monomers having an oxirane group such as glycidyl methacrylate and glycidyl acrylate, and α,β-unsaturated monomers such as acrylic acid, methacrylic acid, and maleic acid monoalkyl esters can be used. Saturated carboxylic acids can be used. Too many unsaturated monomers containing unsaturated amide and oxirane groups tend to reduce the water resistance of the coating film or limit the reaction solvent, so components (A), (B) and
It is preferable to use 30% by weight or less based on the total amount of component (C). Too much α,β-unsaturated carboxylic acid tends to reduce the water resistance of the coating film.
It is preferable to use less than % by weight. The graft copolymer of the present invention is obtained by polymerizing component (B) and optionally component (C) in the presence of component (A). Here, component (A) is 0.5 to 50% by weight,
Component (B) is used in a range of 30 to 50% by weight, and component (C) is used in a range of 69.5 to 0% by weight, so that the total amount is 100% by weight. If component (A) is less than 0.5% by weight, the weather resistance, chemical resistance, etc. of the coating film will decrease, and if it exceeds 50% by weight, it will tend to gel during polymerization of components (A), (B), and (C). . Component (B) is necessary for imparting weather resistance and drying properties. If component (B) is less than 30% by weight, the drying properties of the coating film will be poor, and if it exceeds 50% by weight, the flexibility of the coating film will be poor. Component (C) is used after being adjusted so that the total amount of component (A), component (B), and component (C) is 100% by weight. (A) component, (B) component and (C) component are each 5
It is preferable to use ~40% by weight, 30-50% by weight and 65-10% by weight to give a total of 100% by weight. The polymerization of component (B) and component (C) in the presence of component (A) can be carried out using toluene, xylene, methyl isobutyl ketone, butyl acetate, ethyl acetate, cellosolve acetate, butyl cellosolve, 1-butanol, 2 - Organic solvents such as butanol, 1-propanol, and 2-propanol are used as reaction solvents, and peroxides such as benzoyl peroxide, ditertiary butyl peroxide, and cumene hydroperoxide, and azobisisobutyronitrile are used as polymerization catalysts. The reaction can be carried out by using an azobis-based compound such as azobisvaleronitrile or the like and carrying out a heating reaction at 50 to 200°C for 1 to 10 hours. The reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen gas or under a gas flow. The cellulose ester () of the present invention is necessary to improve the drying properties of the coating film, and cellulose acetate butyrate, nitrocellulose, etc. are used. Cellulose acetate butyrate is particularly preferred from the viewpoint of weather resistance. In the present invention, the graft copolymer () and the cellulose ester () are used so that the weight ratio ()/() is 99/1 to 70/30.
If ()/() exceeds 99/1, the drying properties of the paint film will be poor, and if it reaches the end of 70/30, the solid content of the lacquer must be lowered, and the feeling of the paint film's durability will decrease. do. The resin composition for lacquer of the present invention comprises toluene,
It is used by dissolving it in an appropriate organic solvent such as xylene, methyl isobutyl ketone, butyl acetate, cellosolve acetate, etc. Furthermore, the resin composition for lacquer of the present invention may contain inorganic pigments such as titanium white, cadmium yellow, and carbon black, organic pigments such as phthalocyanine and azo, and plasticizers such as dibutyl phthalate and dioctyl adipate. can do. It is preferable that the pigment be thoroughly kneaded with the graft copolymer (2) before use. The resin composition for lacquer of the present invention is particularly suitable for wood,
Suitable for lacquering building materials such as metal, roof tiles, and slate. Next, synthesis examples and examples related to the present invention will be shown. Hereinafter, "part" means "part by weight". Synthesis Example 1 Fluorine-containing copolymer with hydroxyl group [hydroxyl value
52, molecular weight approximately 80,000 (gel permeation analysis:
A mixed solvent solution of xylene and methyl isobutyl ketone [solid content: 50%; 100 parts of Lumiflon LF-200D (trade name of Asahi Glass Co., Ltd.), 1 part of maleic anhydride, and 1 part of xylene were placed in a flask equipped with a thermometer, a stirrer, and a reflux condenser, and heated at 50°C for 1 hour. Next, a reaction was carried out at 120°C for 2 hours to synthesize a fluorine-containing resin having 0.02 mol of polymerizable carbon-carbon double bonds per 100 g of resin, and a resin solution containing it (solid content
50%). This resin solution had an acid value of 8 and a hydroxyl value of 24. Synthesis Example 2 (Manufacture of copolymer solution) The formulation shown in Table 1 was charged into a flask equipped with a thermometer, a stirrer, a nitrogen gas blowing tube, and a reflux condenser, and heated at 110°C under a nitrogen stream with stirring for 6 hours. Heating for 1 hour, then azobisisobutyronitrile 0.5
1 part and heated at 100℃ for 2 hours to react.
A copolymer was obtained. After this, butyl acetate was added to obtain a suitable solid content. Table 1 shows the solid content and acid value of the obtained copolymer solution.

[Table] Synthesis Example 3 (Synthesis of mixed resin solution) Resin solution containing fluorine-containing resin obtained in Synthesis Example 1 (solid content 50%) and copolymer solution obtained in Synthesis Example 2 () to () were blended in the proportions shown in Table 2. As a result, the solid content and acid value of the resin solution obtained are shown in Table 2.

[Table] Examples 1 to 6 and Comparative Examples 1 to 7 Polymer solution obtained in Synthesis Example 2 () ~
(), mixed resin solution obtained in Synthesis Example 3 ()~
() and a xylene-isobutylketone mixed solvent solution (solid content: 50%) of the above-mentioned fluorine-containing copolymer having a hydroxyl group to produce a lacquer. The lacquer formulation is shown in Table 3. A test plate was prepared using this lacquer, and the drying properties, flexibility, and accelerated weathering resistance of the coating film were tested. The pigment dispersibility of the lacquer was also tested. The results of these tests are shown in Table 4.

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【table】

【table】

[Table] <Test conditions> (1) Test plate preparation conditions Mixture: 3 rolls, 3 passes of the formula in Table 3, xylol/butyl acetate/cellosolve acetate =
Diluted with 5/4/1 (parts by weight) thinner to approximately 13 seconds of food cup #4. Base material: Bonderite #144 treated mild steel plate Painting method: Air spray film thickness: 30-40μ Baking temperature: 80℃ for 60 minutes (2) Durability: Obtained (3) Accelerated weather resistance Q - UV accelerated weather resistance Test machine (USA, Q-
After exposing the sample for a predetermined period of time to a cycle of ultraviolet irradiation at 50° C. for 4 hours and dew condensation at 50° C. for 4 hours, the 60 degree specular reflectance was measured. (4) Pigment dispersibility test Mix 50 parts of the resin (solid content) used in the paint formulation in Table 3 and 3 parts of carbon black, and knead with 3 rolls until the particle size becomes 10μ or less as measured by a particle gauge. The number of times of kneading was measured. Subsequently, the prepared paint was allowed to stand at room temperature for 3 days, and the separation (sedimentation) property of the pigment was examined. Judgment: ○: Not separated ×: Separated The resin composition for lacquer of the present invention provides a coating film with excellent weather resistance, and the composition has excellent pigment dispersibility.

Claims (1)

[Scope of Claims] 1 (A) Reactive carbon-carbon double bonds are bonded to resin 100
0.001 to 0.055 mol per g and 0.5 to 50% by weight of fluorine-containing resins having alkoxy or cyclohexyloxy groups (B) 30 to 50% by weight of methyl methacrylate and (C) 69.5% of other copolymerizable unsaturated monomers Graft copolymer ()70 obtained by blending ~0% by weight so that the total becomes 100% by weight and polymerizing it
A resin composition for lacquer, comprising 99% by weight of cellulose ester and 30-1% by weight of cellulose ester. 2. The fluorine-containing resin of component (A) contains 40 to 60 mol% of fluoroolefin, hydroxyalkyl vinyl ether, and cyclohexyl vinyl ether or alkyl vinyl ether as components,
A fluorine-containing resin obtained by reacting a copolymer with a hydroxyl value of 0.57 to 100 with 0.001 to 0.055 mol of an α,β-unsaturated carboxylic acid or a derivative reactive with its hydroxyl group per 100 g of the copolymer. The resin composition for lacquer according to claim 1.