JPH0426326B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing a graft copolymer by reacting a fluorine-containing resin with an ethylenically unsaturated monomer. (Prior Art) In recent years, there has been a strong demand in the paint industry for paints that are maintenance-free, that is, highly weather resistant, from the viewpoint of resource and energy conservation. Conventionally, acrylic resins have been commonly used for applications that require weather resistance, but there is a desire for even higher levels of resins. Additionally, acrylic resins are generally not compatible with highly oil-absorbing pigments, and their pigment dispersion is particularly poor when it comes to pigments such as carbon black. It has the disadvantage of causing separation. Therefore, in order to improve pigment dispersibility, a method of synthesizing an acrylic resin in the presence of an alkyd resin having an unsaturated carbon-carbon double bond has been reported and practiced. On the other hand, fluorine-containing copolymers containing fluoroolefin, hydroxyalkyl vinyl ether, alkyl vinyl ether, and cyclohexyl vinyl ether as essential components are known. Furthermore, there is a known method for producing a graft copolymer by introducing a reactive carbon-carbon double bond into the fluorine-containing copolymer and polymerizing an ethylenically unsaturated monomer in the presence of the reactive carbon-carbon double bond. (Unexamined Japanese Patent Publication No. 1983-
Publication No. 41315). (Problems to be Solved by the Invention) Although the resin obtained by synthesizing acrylic resin in the presence of the above-mentioned alkyd resin has improved pigment dispersibility, it has poor weather resistance and poor performance compared to the original performance of acrylic resin. The fluorine copolymer has poor chemical resistance, and although the fluorine copolymer has excellent weather resistance, it has poor pigment dispersibility, initial gloss, and the like. Therefore, the above-mentioned graft copolymers have been proposed, and resins having excellent weather resistance, pigment dispersibility, initial gloss, etc. have been obtained. However, the above-mentioned fluorine-containing polymers have insufficient compatibility with ethylenically unsaturated monomers and their polymers, resulting in turbidity in the graft copolymer solution, and pigments being dispersed in the resin. It has disadvantages such as being easy to separate. (Means for Solving the Problems) The present invention provides (A) a copolymer containing a fluoroolefin, a carboxyl group-containing ethylenically unsaturated monomer, a hydroxyalkyl vinyl ether, and a cyclohexyl vinyl ether or an alkyl vinyl ether as a component; , a reactive carbon-carbon double bond obtained by reacting a β-unsaturated carboxylic acid or its hydroxyl group with a reactive derivative, 0.001 to 0.055 mol per 100 g of resin, an alkoxy group or a cyclohexyloxy group, and a carboxyl group. Fluorine-containing resin with 0.5 to 99.5
% by weight of an ethylenically unsaturated monomer copolymerizable with the double bond of component (B) (A). Regarding. The fluorine-containing resin, which is 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. Furthermore, component (A) of the present invention 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, component (A) of the present invention has a carboxyl group. This can improve the compatibility with the ethylenically unsaturated monomer and its polymer, and can prevent turbidity in the graft copolymer solution and separation of the pigment. When component (A) contains fluorine, weather resistance can be improved. 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. Component (A) consists of the following copolymer (a) having a hydroxyl group, and alpha, beta-unsaturated carboxylic acids such as maleic anhydride, acrylic acid, methacrylic acid, acrylic anhydride, methacrylic anhydride, acid chlorides of these, or It can be obtained by reacting the hydroxyl group with a reactive derivative. In this case, the α,β-unsaturated carboxylic acid or its hydroxyl group-reactive derivative is reacted in an amount of 0.001 to 0.055 mol per 100 g of the hydroxyl group-containing copolymer (a). The above copolymer (a) includes fluoroolefins such as chlorotrifluoroethylene, trifluoroethylene, and tetrafluoroethylene, unsaturated acids such as maleic acid, fumaric acid, acrylic acid, and methacrylic acid, and carboxyethyl vinyl ether and carboxypropyl vinyl ether. Ethylenically unsaturated monomers having a carboxyl group such as carboxyalkyl vinyl ethers or fluorine-substituted compounds thereof, and carboxyalkyloxyalkyl vinyl ethers or fluorine-substituted compounds thereof, hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether , hydroxyalkyl vinyl ethers such as hydroxyhexyl vinyl ether, and alkyl vinyl ethers or cyclohexyl vinyl ethers such as ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, etc., in which the hydrogen of these alkyl groups or vinyl groups is replaced with fluorine. It is a copolymer obtained by
Vinylidene chloride, vinyl acetate, vinyl n-butyrate,
It may also contain methyl methacrylate and the like as a copolymerization component. The fluoroolefin is 40 to 60 mol% in the copolymer (a), the hydroxyalkyl vinyl ether has a hydroxyl group of 0.57 to 250, especially 3 to 70, and the carboxyl group has an acid value of 0.5 to 20, especially 1.0 to 10. It is preferable to use it as follows. 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 250, preferably 3 to 70. If the hydroxyl value is less than 0.57, it will be difficult for the 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. In addition, the acid value is 0.5 to 20, preferably 1.0 to 20.
It is 10. If the acid value is less than 0.5, the compatibility with ethylenically unsaturated monomers and their polymers will be poor, and if it is 10 or more, the solubility in organic solvents will tend to be limited. 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 (B) includes alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, isopropyl acrylate, and 2-ethylhexyl acrylate, similar alkyl methacrylates, substituted styrenes such as styrene or vinyltoluene, α-methylstyrene, and chlorostyrene; Acrylonitrile, methacrylonitrile, vinyl chloride, vinyl acetate, maleic acid dialkyl esters can be used, and
Hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, similar hydroxyalkyl methacrylates, monoacrylates or monomethacrylates of polyhydric alcohols such as glycerin, trimethylolpropane, N-methylol acrylamide , N
- An ethylenically unsaturated monomer having a hydroxyl group such as methylolmethacrylamide 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, α,
β-unsaturated carboxylic acids can be used. Too much unsaturated monomer containing unsaturated amide and oxirane groups may reduce the water resistance of the coating film,
Because the reaction solvent tends to be limited,
It is preferable to use 30% by weight or less based on the total amount of components (A) and (B), and too much α,β-unsaturated carboxylic acid tends to reduce the water resistance of the coating film. It is preferable to use it in an amount of 10% by weight or less. The graft copolymer of the present invention is obtained by polymerizing component (B) in the presence of component (A). Here, (A)
Ingredients are 0.5 to 99.5% by weight and component (B) is 99.5 to 0.5
% by weight used. The ratio of (A) component and (B) component is (A)/(B)
If the ratio (weight ratio) is less than 0.5/99.5, the weather resistance and chemical resistance of the coating film will decrease, and if it exceeds 99.5/0.5, the dispersibility, drying properties, and compatibility with other resins of the pigment will decrease. Component (A) and component (B) are each 10 to 90
It is preferred to use 90-10% by weight. In addition, the hydroxyl group of the graft copolymer can be adjusted by the hydroxyl value of component (A) and its usage amount, and the usage amount of the ethylenically unsaturated monomer having a hydroxyl group among component (B), and the acid value is ( It can be adjusted by the acid value of component A) and the amount of α,β-unsaturated carboxylic acid used in component (B). The graft copolymer obtained by the present invention can be dissolved in an organic solvent to form a lacquer paint, or can be appropriately combined with a curing agent known as a curing agent for acrylic resin paints to form a curable paint. . Thus, when used as a paint, 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. It is preferable to use such a pigment by thoroughly kneading it with the graft copolymer in advance. The above-mentioned paints are particularly suitable as paints for building materials such as wood, metal, slate, and roof tiles. The polymerization of component (B) in the presence of component (A) may optionally include toluene, xylene, methyl isobutyl ketone, butyl acetate, ethyl acetate, cellosolve acetate,
Organic solvents such as butyl cellosolve, 1-butanol, 2-butanol, 1-propanol, and 2-propanol are used as reaction solvents, and peroxides such as benzoyl peroxide, ditertiary butyl peroxide, and cumene hydroperoxide are used as polymerization catalysts. The reaction can be carried out by using an azobis-based compound such as azobisisobutyronitrile or the like and carrying out a heating reaction at 50 to 200°C for 1 to 10 hours. The reaction is
It is preferable to carry out the reaction in an atmosphere or stream of an inert gas such as nitrogen gas. As a polymerization catalyst, peroxide is preferable in order to improve the grafting rate. In order to reduce the amount of residual monomer, peroxide and azobis It is preferable to use these compounds together. Polymerization can be carried out not only by bulk polymerization and solution polymerization, but also by suspension polymerization, emulsion polymerization, etc., if necessary. (Example) Next, synthesis examples and examples related to the present invention will be shown. Hereinafter, "part" means "polymerization part". Synthesis Example 1 Fluorine-containing copolymer with hydroxyl group [hydroxyl value
52, molecular weight approximately 80,000 (gel permeation analysis:
Calibrated with standard polystyrene), trifluoroethylene approximately 50 mol%, hydroxybutyl vinyl ether approximately 9 mol%, ethyl vinyl ether approximately 23 mol%
and about 18 mol% cyclohexyl vinyl ether
A mixed solvent solution of xylene and methyl isobutyl ketone [solid content
50%, Lumiflon LF-200D, (Asahi Glass Co., Ltd. product name)
Use: Charge 100 parts of maleic anhydride, 0.25 parts of maleic anhydride, and 1 part of xylene into a flask equipped with a thermometer, stirrer, and reflux condenser, and heat at 50°C for 1 hour.
A fluorine-containing resin containing 0.02 mol of polymerizable carbon-carbon double bonds in 100 g of resin was synthesized by reacting at 120°C for 2 hours, and a resin solution containing it (solid content 50
%) was obtained. This resin solution had an acid value of 2 and a hydroxyl value of 25. Synthesis Example 2 Fluorine-containing copolymer [hydroxyl value 47, acid value 5, trifluoroethylene approximately 50 mol%, acrylic acid approximately 1
A mixed solvent solution of xylene and methyl isobutyl ketone [solid content: 50%; Viscosity approximately 800 cps (room temperature), Lumiflon LF-400 (Asahi Glass
Co., Ltd. (trade name) used] 100 parts, 0.25 parts of maleic anhydride, and 1 part of xylene were placed in a flask equipped with a thermometer, a stirrer, and a reflux condenser, and reacted at 50°C for 1 hour and then at 120°C for 2 hours. In this way, a fluorine-containing resin having 0.02 mole of polymerizable carbon-carbon double bonds in 100 g of resin was synthesized, and a resin solution (solid content: 50%) containing it was obtained. This resin solution has an acid value of 4
and a hydroxyl value of 22. Examples 1 to 3 and Comparative Examples 1 to 3 The formulations shown in Table 1 were charged into a flask equipped with a thermometer, a stirrer, a nitrogen gas blowing tube, and a reflux condenser, and heated under a nitrogen stream at 110°C for 6 hours while stirring. Heating for 1 hour, then azobisisobutyronitrile 0.5
1 part and heated at 100℃ for 2 hours to react.
A copolymer was obtained. After that, butyl acetate was added to make the solid content 40% by weight. Table 1 shows the acid value of the obtained copolymer solution.

[Table] Accelerated weathering tests and pigment dispersibility tests were conducted using the copolymer solutions (solid content 40%) obtained in Examples 1 to 3 and Comparative Examples 1 to 3. The results are shown in Table 2.

[Table] <Test conditions> (1) Accelerated weathering test () For each solution with solid content exceeding 30%,
Bonderite #144 treated mild steel plate adjusted to 30% solid content with toluene (manufactured by Nippon Test Panel Co., Ltd.)
Apply the film to a thickness of 30μm using bar coater #60, and after setting for 20 minutes, heat at 80℃.
It was dried for 20 minutes and used as a test plate. () Using a Q-UV accelerated weathering tester (manufactured by Q-Panel, USA), the prepared test plate was subjected to a cycle of UV irradiation at 50°C for 4 hours and dew condensation at 50°C for 4 hours for a specified period of time. After that, the 60 degree specular reflectance was measured. (2) Pigment dispersibility test 50 parts of each solution (solid content) and 3 parts of carbon black were mixed and kneaded using three rolls until the particle size became 10 μm or less as measured by a particle gauge. Subsequently, the prepared paint was allowed to stand at room temperature for 3 days, and the separation (sedimentation) property of the pigment was examined. (3) State of resin solution The graft copolymer was placed in a 300 c.c. glass beaker, and the state of the resin at 23°C was visually observed for transparency. (Effects of the Invention) The graft copolymer obtained by the present invention can be used as a raw material for paints, provides a coating film with excellent weather resistance, and itself has excellent pigment dispersibility.

Claims (1)

[Scope of Claims] 1 (A) A copolymer containing a fluoroolefin, a carboxyl group-containing ethylenically unsaturated monomer, a hydroxyalkyl vinyl ether, and a cyclohexyl vinyl ether or an alkyl vinyl ether as a component, and an α,β-unsaturated carboxylic acid. or 0.001 to 0.055 mol of reactive carbon-carbon double bonds per 100 g of resin, obtained by reacting its hydroxyl group with a reactive derivative;
A method for producing a graft copolymer, which comprises polymerizing 99.5 to 0.5% by weight of an ethylenically unsaturated monomer copolymerizable with the double bond of component (B) (A) in the presence of 99.5% by weight. . 2. The fluorine-containing resin of component (A) contains 40 to 60 mol% of fluoroolefin, a carboxyl group-containing ethylenically unsaturated monomer, hydroxyalkyl vinyl ether, and cyclohexyl vinyl ether or alkyl vinyl ether, and has a hydroxyl value of 0.57 to 250. and a copolymer having an acid value of 0.5 to 20, α,β-unsaturated carboxylic acid or a derivative reactive with its hydroxyl group per 100 g of the copolymer.
The method for producing a graft copolymer according to claim 1, which is a fluorine-containing resin obtained by reacting 0.001 to 0.055 moles.