JPH051118A - Fluorine-containing copolymer and coating compound comprising the same copolymer as constituent component - Google Patents

Abstract

PURPOSE:To obtain the copolymer providing a coating compound having excellent solubility in organic solvents, excellent weather resistance, water and oil repellency, etc., comprising a copolymerized unit such as fluoroolefin and a fluoroalkyl-containing (meth)acrylate copolymerized unit. CONSTITUTION:(A) 5-95mol% (preferably 30-70mol%) fluoroolefin (preferably tetrafluoroethylene) copolymerized unit is blended with (B) 0.1-95mol% (preferably 0.1-60mol%) fluoroalkyl-containing (meth)acrylate (e.g. compound shown by the formula) copolymerized unit and preferably (C) <=50mol% functional group-containing vinyl monomer (e.g. 2-hydroxyethylethyl vinyl ether) copolymerized unit and/or (D) <=50mol% another vinyl monomer (preferably vinyl monomer into which cyclic hydrocarbon is introduced through urethane bond) and a polymerization initiator, and copolymerized to give the objective copolymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel fluorine-containing copolymer and a paint containing it as a main component.

[0002]

2. Description of the Related Art Conventionally, fluorine-containing copolymers are widely used in many fields because they are extremely excellent in heat resistance, mechanical properties, chemical resistance, weather resistance and the like. One of its uses is as a coating film forming component of paint. For example, a fluororesin paint using a tetrafluoroethylene polymer or a vinylidene fluoride polymer is known, which has excellent lubricity, non-adhesiveness, weather resistance and chemical resistance. It is used as a material in the chemical industry, food, construction, machinery and other fields.

However, the fluororesin coating composition has a drawback that it needs to be baked at a high temperature and the range of use is inevitable. Therefore, in recent years, it is soluble in an organic solvent and at room temperature. Attempts have been made to develop solvent-based paints using a fluorine-containing copolymer having a curable reactive group. Incidentally, examples of the fluorine-containing copolymer soluble in an organic solvent include, for example, JP-A-57-34107 and JP-A-61-275.
311, JP-A-61-57609, JP-A-62-1
A copolymer of a fluoroolefin and a vinyl monomer copolymerizable therewith, which is found in JP-A-74213 and JP-A-63-182312, is known.

However, although these copolymers have excellent weather resistance of the cured coating film, they are still insufficient in water and oil repellency, which is one of the characteristics of the fluorine-containing copolymer. It is said.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a fluorine-containing copolymer in which the above-mentioned problems of the prior art are solved, that is, a fluorine-containing copolymer having good solubility in an organic solvent and compatibility with a curing agent. , And a fluorine-based coating composition containing the composition as a main component, which is hard and has excellent weather resistance, and which is remarkably improved in water and oil repellency.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in view of the above-mentioned problems, and as a result, by using a specific monomer as a polymerizing monomer of a fluorine-containing copolymer, the above-mentioned problems can be solved. The inventors have found that the above can be solved and completed the present invention. That is, the present invention is: A fluorinated copolymer comprising the following components. (A) Fluoroolefin copolymerized unit 5 to 95 mol% (B) Fluoroalkyl group-containing (meth) acrylate copolymerized unit 0.1 to 95 mol% and the fluorine-containing copolymer as a constituent component And the paint.

The present invention will be described in detail below. In the fluorocopolymer of the present invention, the fluoroolefin forming the unit (A) is represented by the formula (a)

[0008]

[Chemical 1]

What is represented by is used. Specific examples of such a vinyl monomer include, for example,

[0010]

[Chemical 2]

Fluoroethylene such as;

[0012]

[Chemical 3]

A fluoropropene system such as;

[0014]

[Chemical 4]

Examples thereof include fluoroolefin compounds having 4 or more carbon atoms. Among these, among these,
(A ') expression

[0016]

[Chemical 5]

Fluoroethylene compounds and fluoropropene compounds are preferable indicated by [0017], in particular tetrafluoroethylene (CF ₂ = CF _2), chlorotrifluoroethylene (CF ₂ = CFCl) and hexafluoropropene (CF ₂ = CFCF ₃₎ is It is suitable. These fluoroolefins may be used alone or in combination of two or more.

In the fluorine-containing copolymer of the present invention,
The content of the (A) unit is 5 to 95 mol%, preferably 30.
It is necessary to be in the range of 70 mol%. If this content is less than 5 mol%, the weather resistance is insufficient, and if it exceeds 95 mol%, the solubility in organic solvents decreases. Specific examples of the acrylate or methacrylate having a fluoroalkyl group forming the unit (B) in the fluorine-containing copolymer of the present invention (hereinafter referred to as (meth) acrylate having a fluoroalkyl group) include, for example,

[0019]

[Chemical 6]

And the like. These may be used alone or in combination of two or more. In the fluorocopolymer of the present invention, the content of the (B) unit is 0.1 to 95 mol%, preferably 0.1 to 6
It should be in the range of 0 mol%. If this content is less than 0.1 mol%, the water and oil repellency of the cured coating film will be insufficient.

In the fluorine-containing copolymer of the present invention, in addition to the units (A) and (B), a vinyl monomer having a functional group (C) is copolymerized within a range not exceeding 50 mol%. It is preferable to include units and / or (D) units copolymerized with other vinyl monomers. Examples of the functional group-containing vinyl monomer forming the unit (C) include a hydroxyl group-containing vinyl monomer represented by the formula (c-1) and an epoxy group-containing vinyl monomer represented by the formula (c-2). And a hydrolyzable silyl group-containing vinyl monomer represented by the formula (c-3).

[0022]

[Chemical 7]

Hydroxyl group-containing vinyl monomer [(c-1) formula]
Specific examples of 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, 4
-Hydroxyalkyl vinyl ethers such as hydroxycyclohexyl vinyl ether, 2-hydroxyallyl vinyl ether, hydroxyalkyl allyl ethers such as 4-hydroxybutyl allyl ether, 2-hydroxyethyl (meth) acrylate, 4-hydroxypropyl (meth) acrylate, etc. Hydroxyl group-containing (meth) acrylates, 2-hydroxyethyl crotonate, 4
Typical examples are hydroxyl group-containing crotonic acid esters such as hydroxypropyl crotonate, allyl alcohol, and the like. Among these, hydroxyalkyl vinyl ethers are preferable because of their good reactivity with fluoroolefins.

Epoxy group-containing vinyl monomer [(c-2)
Formula], for example,

[0025]

[Chemical 8]

And the like. Specific examples of the hydrolyzable silyl group-containing vinyl monomer [(c-3) formula] include, for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyldimethoxymethylsilane, allyltrimethoxysilane, and allyltriethoxysilane. , Allyldimethoxymethylsilane, vinyloxypropyltrimethylsiloxysilane, vinyloxyethoxypropyltrimethylsiloxysilane, 3-trimethoxysilylpropyl (meth) acrylate, and the like.

The functional group-containing vinyl monomer forming the unit (C) may be used alone or in combination of two or more kinds. Examples of the other copolymerizable vinyl monomer forming the unit (D) include olefins such as ethylene, propylene and isobutylene,
Haloolefins such as vinyl chloride and vinylidene chloride, vinyl acetate, vinyl n-butyrate, vinyl benzoate, pt-
Vinyl butyl benzoate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl versatate, vinyl laurate, and other carboxylic acid vinyl esters, isopropenyl acetate, isopropyl isopropenyl, and other carboxylic acid isopropenyl esters, ethyl vinyl ether , Propyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether,
Chain alkyl vinyl ethers such as neopentyl vinyl ether, 2-ethylhexyl vinyl ether and octyl vinyl ether, fluorovinyl ethers such as pentafluoroethyl vinyl ether and 2-perfluorooctylethyl vinyl ether, cycloalkyl vinyl ethers such as cyclopentyl vinyl ether and cyclohexyl vinyl ether, phenyl Aryl vinyl ethers such as vinyl ether, aralkyl vinyl ethers such as benzyl vinyl ether and phenethyl vinyl ether, aromatic vinyl compounds such as styrene and vinyltoluene Allyl formate, allyl acetate, allyl butyrate, allyl benzoate, allyl cyclohexanecarboxylate, allyl cyclohexylpropionate Allyl esters such as, allyl ethyl ether, allyl Allyl ethers such as phenyl ether, butyl (meth) acrylate, methyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxy-4
Acrylic acid and methacrylic acid esters such as-(2-methacryloxyethoxy) benzophenone, acrylamides such as acrylamide and N-methylol acrylamide, and further Japanese Patent Application No. 1-237122, Vinyl monomer having cyclic hydrocarbon group introduced through urethane bond, and Japanese Patent Application No. 2-101695
Examples thereof include vinyl ethers in the ring, and the like.

Among these, as disclosed in Japanese Patent Application No. 1-237122, a vinyl monomer introduced with a cyclic hydrocarbon group through a urethane bond, and Japanese Patent Application No. 2-237122.
As disclosed in Japanese Patent No. 101695, a fluorine-containing copolymer using an endocyclic vinyl ether is preferable because it has excellent compatibility with a curing agent, hardness and gloss. These vinyl monomers may be used alone or in combination of two or more.

The fluorine-containing copolymer of the present invention initiates polymerization of a predetermined proportion of the vinyl monomer mixture essentially including the above formulas (a) and (b) in the presence or absence of a solvent. It can be produced by copolymerization using a polymerization initiator or ionizing radiation as a source. As the polymerization initiator, a water-soluble one or an oil-soluble one is appropriately used depending on the type of polymerization or desired.

Examples of the oil-soluble initiator include azo compounds such as azobisisobutyronitrile and 2,2'-azobis- (2,4-dimethylvaleronitrile), t-butyl peroxypivalate and t-butyl. Peroxyester type peroxides such as peroxyisobutyrate, octanoyl peroxide, diacyl peroxide type peroxides such as lauroyl peroxide, dialkyl peroxydicarbonate type peroxides such as diisopropyl peroxydicarbonate, Examples thereof include dialkyl peroxide type peroxides such as benzoyl peroxide.

As the water-soluble polymerization initiator, for example, a persulfate such as potassium persulfate, hydrogen peroxide, or a redox initiator comprising a combination of these with a reducing agent such as sodium hydrogen sulfite or sodium thiosulfate, and further ,
Inorganic initiators such as those in which a small amount of iron, ferrous salt, silver nitrate, etc. coexist, dibasic acid peroxides such as disuccinic acid peroxide, diglutaric acid peroxide, and monosuccinic acid peroxide, azobi Examples include organic initiators such as perisobutylamidine dibasic acid salt. The amount of these polymerization initiators to be used is appropriately selected depending on the kind, the conditions of the copolymerization reaction, etc., but 0.005 to 5% by weight, preferably 0. 0
It is selected in the range of 5 to 0.5% by weight.

The polymerization method is not particularly limited and, for example, a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method, a solution polymerization method and the like can be used. From the viewpoint of stability of the polymerization reaction operation, etc. Solvents such as lower alkyl-substituted benzenes such as xylene and toluene, esters such as butyl acetate, ketones such as methyl isobutyl ketone, alcohols such as t-butanol, and saturated halogenated hydrocarbons having one or more fluorine atoms are used as a solvent. The solution polymerization method, the emulsion polymerization method in an aqueous medium, the bulk polymerization method that does not require separation from the solvent, and the like are preferably used.

When copolymerization is carried out in an aqueous medium, a suspension agent or an emulsifier is usually used as a dispersion stabilizer, and a basic buffer is added to adjust the pH value of the reaction solution during polymerization to 4, preferably. It is desirable to set it to 6 or more. Also in the case of the solution polymerization method and the bulk polymerization method, addition of a basic substance such as potassium carbonate or an amine compound is effective. Further, the polymerization system is not particularly limited, and any of batch system, semi-continuous system and continuous system can be used.

The reaction temperature in the copolymerization reaction is usually −
Within the range of 30 to + 150 ° C, it is appropriately selected depending on the type of the polymerization initiation source and the polymerization medium, and is usually selected in the range of 0 to 100 ° C, preferably 10 to 90 ° C. The reaction pressure is not particularly limited, but is selected from the range of normal pressure to 100 kg / cm ² . Further, the copolymerization reaction can be carried out by adding an appropriate chain transfer agent.

The molecular weight of the fluorine-containing copolymer of the present invention is determined by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent and monodisperse polystyrene having a known molecular weight as a standard substance. Mn) is in the range of 500 to 200,000, preferably 2,000 to 100,000, and the glass transition temperature (Tg) is usually -50 to 120 ° C, preferably -1.
It is 0 to 100 ° C.

The fluorine-containing copolymer of the present invention having such a composition, molecular weight and glass transition temperature is soluble in an organic solvent and excellent in compatibility with a curing agent, and is mainly composed of the fluorine-containing copolymer. The cured coating film of the paint as a component is glossy, has excellent hardness and weather resistance, and has significantly improved water and oil repellency. In the fluorocopolymer of the present invention,
(C) As a functional group-containing vinyl monomer forming a unit,
When a hydroxyl group-containing vinyl monomer is used, the resulting fluorine-containing copolymer has a hydroxyl group as a curing site, and is a curing agent used in ordinary thermosetting acrylic paints, for example, polyvalent isocyanate. It can be heat-cured by using a nato, a block isocyanate hardener, a melamine hardener, a urea resin hardener, a polybasic acid hardener and the like.

Furthermore, the hydroxyl group-containing fluorine-containing copolymer can be cured at room temperature by using polyvalent isocyanates. Preferred examples of the polyvalent isocyanates include non-yellowing diisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate and adducts thereof, and polyvalent isocyanates having an isocyanurate ring. Among these, a polyvalent isocyanate having an isocyanurate ring, which has a good compatibility with the fluorine-containing copolymer, is particularly preferable. When using these polyvalent isocyanates for room temperature curing, a catalyst such as dibutyltin dilaurate may be added to accelerate the curing.

In the fluorine-containing copolymer of the present invention,
(C) As a functional group-containing vinyl monomer forming a unit,
When an epoxy group-containing vinyl monomer is used, the resulting fluorine-containing copolymer has an epoxy group as a curing site, and polyamines, acid anhydrides, polyphenols, polymercaptans as curing agents. By using a polyaddition type curing agent such as a class of compounds or a catalyst type curing agent such as imidazole, BF ₃ or the like, heat curing or room temperature curing can be performed.

Further, in the fluorine-containing copolymer of the present invention, when a hydrolyzable silyl group-containing vinyl monomer is used as the functional group-containing vinyl monomer forming the (C) unit, it was obtained. The fluorine-containing copolymer has a hydrolyzable silyl group as a curing site, and can be moisture-cured using an amine compound such as butylamine or a curing catalyst such as dibutyltin dilaurate.

The fluorine-containing copolymer of the present invention can be used as a lacquer type coating material when it does not contain the above-mentioned (C) unit. The present invention provides a fluorine-based coating composition containing the novel fluorine-containing copolymer as a main component together with the above novel fluorine-containing copolymer. Can be used.

Examples of the solvent include aromatic hydrocarbons such as toluene and xylene, alcohols such as n-butanol, esters such as n-butyl acetate, ketones such as methyl isobutyl ketone, glycols such as ethyl cellosolve. Examples thereof include ethers and various commercially available thinners. The solution-type paint is prepared by mixing the fluorine-containing copolymer and a solvent with a mixer which is usually used for preparing paints, such as a ball mill, a paint shaker, a sand mill, a jet mill, a three-roll mill and a kneader. It can be carried out by homogeneous mixing. At this time, if desired, a pigment, a dispersion stabilizer, a viscosity modifier, a leveling agent, an antigelling agent, an ultraviolet absorber, etc. can be added.

[0042]

[Monomer]

CTFE: chlorotrifluoroethylene HBVE: 4-hydroxybutyl vinyl ether IBVE: isobutyl vinyl ether CHVE: reaction product of cyclohexyl isocyanate and 4-hydroxybutyl vinyl ether DHF: 2,3-dihydrofuran MMA: methyl methacrylate IBMA: isobornyl methacrylate HEMA : 2-Hydroxyethyl Methacrylate FOEM: 2-Perfluorooctylethyl Methacrylate FOEA: 2-Perfluorooctylethyl Acrylate [Polymerization Initiator] PBPV: t-Butylperoxypivalate Also, the examples are measured by the following measuring methods went.

[Molecular Weight of Various Resins] The molecular weight of the copolymer was obtained from a polystyrene standard calibration curve using gel permeation chromatography. Equipment used: Equipment: Shimadzu LC-3A Column: Tosoh Corporation TSKgel G-5000 HXL TSKgel G-4000 HXL TSKgel G-2000 HXL Detector: Shimadzu RID-6A Data processing: Shimadzu C-R4A Carrier: Tetrahydrofuran [Hydroxyl Value] The hydroxyl value was measured according to JIS K-0070.

[Paint Evaluation Method] Compatibility: The transparency of the coating film was visually evaluated. ． Coating gloss: Measured according to JIS K-5400. ． Weather resistance: In accordance with ASTM G-53, accelerated weather resistance test is performed with a "QUV" tester manufactured by Q Panel Co., Ltd. to obtain 3000.
A gloss retention of 90% or more after a lapse of time was regarded as acceptable.

.. Water repellency: The contact angle of the coating film with water was measured. ． Oil repellency: The contact angle of the coating film with tetradecane was measured.

[0046]

Examples 1 to 4 In a stainless steel autoclave having an internal volume of 1 liter, 7.7 g of potassium carbonate was charged, and after nitrogen substitution, the monomers, the initiator and the solvent shown in Table 1 were charged.
Polymerization was performed at 67 ° C. for 8 hours. After completion of the polymerization, the autoclave was opened and the produced copolymer solution was taken out.
After potassium carbonate was filtered off from this copolymer solution, it was reprecipitated with n-hexane and dried.

[0047]

Examples 5 to 8 Each of the fluorine-containing copolymers obtained in Examples 1 to 4 adjusted to a solid content of 50% with xylene was used as a main agent, and "duranate TPA" was used as a curing agent.
(Asahi Kasei Co., Ltd.) was blended so that NCO / OH = 1/1, and the coating was performed by adjusting the Ford cup # 4 for 15 seconds with xylene as a thinner. After baking the obtained coating film at 120 ° C. for 1 hour, coating film properties (coating appearance, coating gloss, weather resistance, water repellency, oil repellency)
Was measured.

The results are shown in Table 2.

[0049]

[Comparative Examples 1 and 2] 7.7 g of potassium carbonate was charged into a stainless steel autoclave having an internal volume of 1 liter, and after nitrogen substitution, monomers, an initiator and a solvent shown in Table 1 were charged,
Polymerization was performed at 67 ° C. for 8 hours. After completion of the polymerization, the autoclave was opened and the produced copolymer solution was taken out.
After potassium carbonate was filtered off from this copolymer solution, it was reprecipitated with n-hexane and dried.

[0050]

[Comparative Examples 3 and 4] Each of the fluorine-containing copolymers obtained in Comparative Examples 1 and 2 adjusted to a solid content of 50% with xylene was used as a main agent, and "Duranate TPA" was used as a curing agent.
(Asahi Kasei Co., Ltd.) was blended so that NCO / OH = 1/1, and the coating was performed by adjusting the Ford cup # 4 for 15 seconds with xylene as a thinner. After baking the obtained coating film at 120 ° C. for 1 hour, coating film properties (coating appearance, coating gloss, weather resistance, water repellency, oil repellency)
Was measured.

The results are shown in Table 2.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

As can be seen from Table 2, the resin according to the present invention is excellent in compatibility, gloss and weather resistance, and is remarkably excellent in water repellency and oil repellency. Further, the fluorine-based coating material of the present invention containing the fluorine-containing resin as a main component can give a coating film which is glossy and hard, and which has excellent adhesion to a substrate and excellent weather resistance under mild conditions. For example, it is useful as a baking paint for a colored hard plate, a colored aluminum plate, an aluminum sash, or as a normally dry paint that can be applied on site.

Further, regarding the material of the substrate, in addition to metallic materials, inorganic materials such as glass and concrete, FRP,
It is preferably used for coating plastics such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyvinyl chloride and polyvinylidene chloride, and organic materials such as wood. Further, the fluorine-based paint is also useful in specific applications such as automobile top coats, exterior colored glass, and cement roof tiles.

Claims (2)

[Claims] 1. A fluorine-containing copolymer comprising the following components. (A) Fluoroolefin copolymerized unit 5 to 95 mol% (B) Fluoroalkyl group-containing (meth) acrylate copolymerized unit 0.1 to 95 mol% 2. A paint comprising the fluorine-containing copolymer according to claim 1 as a constituent component.