JPH1036755A - Coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coating composition capable of providing coating film excellent in water repellency as well as weatherability inherent in the fluororesin, and capable of retaining the surface properties of the coating film over a long period. SOLUTION: This coating composition comprises (A) 0.01-30 pts.wt. of a block or graft copolymer composed of polysiloxane group-bearing polymer segments and poly(meth)acrylic ester or polyester polymer segments, (B) 100 pts.wt. of a fluorocopolymer composed of fluoroolefin unit, carboxylic vinyl ester unit and optional other monomer unit(s), and an organic solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fluororesin coating composition having excellent weather resistance and water repellency.

[0002]

2. Description of the Related Art Conventionally, resin compositions such as acrylic melamine resin, acrylic urethane resin, alkyd resin and the like have been used as general-purpose coating resins, but these resins do not have sufficient properties such as weather resistance and water repellency. I can not say. On the other hand, as a resin having excellent weather resistance and water repellency, a fluorine-containing copolymer has recently attracted attention. However, paints using the fluorinated copolymer alone are repellent because fluoroolefins and vinyl ethers and vinyl esters are copolymerized in order to impart solvent solubility to the fluorinated copolymer. The current situation is that the water is impaired.

[0003] For this reason, a coating film formed from a fluororesin paint obtained by using these fluoroolefin copolymers has a problem that water droplets applied to the coating film surface remain as water marks after drying and become stains, There is a problem that the water repellency is reduced by outdoor use for a period, that is, the water repellency is insufficient.

[0004] In order to improve these problems, it has been proposed to mix a polysiloxane compound with the fluorine-containing copolymer. For example, JP-A-3-182538 and JP-A-5-65451 disclose a resin composition for a paint comprising a mixture of a fluoroolefin copolymer and a polydimethylsiloxane compound.

[0005] However, various problems arise when polydimethylsiloxane is mixed with a coating varnish. For example, polysiloxane compounds are commonly referred to as "repellent" and are responsible for significant defects in the coating film, and if there is not sufficient compatibility between the coating composition and the polysiloxane compound, the coating is rather rejected. This will lead to film defects. Further, even if there is sufficient compatibility between the polysiloxane compound and the fluorinated copolymer, in the case of a simple mixture, the polysiloxane compound which is a substance exhibiting water repellency is applied over time. It is eluted from the surface of the film, causing a problem that the water repellency is not maintained in a short time.

[0006]

DISCLOSURE OF THE INVENTION The present invention is directed to a paint having excellent weather resistance and water repellency obtained by adding a polysiloxane compound to a fluorine-containing copolymer, and furthermore, because the components are rich in compatibility. An object of the present invention is to provide a coating composition capable of maintaining initial surface properties for a long period of time.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a polysiloxane compound contains a specific polysiloxane compound having a portion compatible with a fluorine-containing copolymer. By blending with a fluorocopolymer, it has been found that a coating composition capable of forming a coating film that is excellent in weather resistance, water repellency, and can maintain initial surface properties for a long period of time can be obtained, and completed the present invention. Was.

That is, the present invention relates to a block copolymer or graft copolymer (A) comprising a polysiloxane group-containing polymer portion and a polymer portion comprising a poly (meth) acrylate or polyester, and a fluoroolefin unit. A coating composition comprising a fluorine-containing copolymer (B) comprising a carboxylic acid vinyl ester unit and optionally other monomer units, and an organic solvent.

Hereinafter, the present invention will be described in more detail. The fluorine-containing copolymer (B), which is one of the main components of the coating composition of the present invention, can be obtained by polymerizing a monomer mixture containing fluoroolefin and vinyl carboxylate as essential components.

The fluoroolefin used for producing the fluorine-containing copolymer (B) is, for example, tetrafluoroethylene, chlorotrifluoroethylene, 1,1-difluoroethylene, hexafluoropropylene, hexafluoroisobutene and the like. Can be used alone or as a mixture.

The vinyl carboxylate used for producing the fluorine-containing copolymer (B) is, for example, vinyl acetate,
Vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl isocaproate, vinyl pivalate, vinyl caprylate, vinyl caproylate, vinyl stearate, Veova 9 and Veova 10 (shell chemistry)
Co., Ltd.), vinyl cyclohexanoate, vinyl benzoate, p
-Vinyl toluate, vinyl p-tert-butylbenzoate and the like, which can be used alone or as a mixture.

The other monomers used in the production of the fluorine-containing copolymer (B) according to the present invention include various monomers, and particularly preferred are hydroxyalkyl allyl ethers and allyl alcohol. No.

The hydroxyalkyl allyl ethers used for producing the fluorine-containing copolymer (B) include 2-allyloxy-1-ethanol, 3-allyloxy-1-propanol, 4-allyloxy-1-butanol, -Allyloxy-1-pentanol, 6-allyloxy-1-hexanol, 7-allyloxy-1-heptanol, 8-allyloxy-1-octanol, 1,
2-dihydroxypropyl allyl ether, 4-hydroxycyclohexyl allyl ether, 1,4-cyclohexane dimethanol allyl ether, 2,2-dimethyl-3-hydroxypropyl allyl ether, and the like, and these may be used alone or as a mixture. it can.

The fluorine-containing copolymer (B) according to the present invention can be used by selecting from a wide range of polymerizable compounds other than the above-mentioned monomers, and examples thereof include the following compounds. be able to.

(A) alkyl vinyl ethers or aryl vinyl ethers, (b) carboxylic acid isopropenyl esters, (c) (meth) acrylic esters, (d)
Alkyl allyl ethers or aryl allyl ethers, (e) α-olefins, (f) unsaturated carboxylic acids and esters thereof, (g) hydroxyalkyl vinyl ethers, (h) hydroxycarboxylic acid vinyl esters, ) Hydroxyalkyl (meth) acrylates, (nu) organic silicon group-containing vinyl compounds having a hydrolyzable group, (l) other polymerizable compounds.

The alkyl vinyl ethers or aryl vinyl ethers of (a) include, for example, ethyl vinyl ether, propyl vinyl ether, isopropyl vinyl ether, butyl vinyl ether, tert-butyl vinyl ether, pentyl vinyl ether, hexyl vinyl ether, isohexyl vinyl ether, octyl vinyl ether, 4-methyl -1- Chain alkyl vinyl ethers such as pentyl vinyl ether. Examples thereof include cycloalkyl vinyl ethers such as cyclopentyl vinyl ether and cyclohexyl vinyl ether, and aryl vinyl ethers such as phenyl vinyl ether and toluyl vinyl ether.

The carboxylic acid isopropenyl esters (b) include, for example, isopropenyl acetate, isopropenyl propionate and the like. (C) (meth) acrylates include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate,
N-butyl (meth) acrylate, isobutyl (meth) acrylate, -tert-butyl (meth) acrylate,
Cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, (meth) ) Lauryl acrylate, benzyl (meth) acrylate and the like. Further, (meth) acrylates having an unsaturated alkyl group such as allyl acrylate and allyl methacrylate can also be used as similar compounds.

The alkyl allyl ethers or aryl allyl ethers of (d) include, for example, ethyl allyl ether, butyl allyl ether, cyclohexyl allyl ether and the like.

The α-olefins of (e) include, for example, ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene,
1-decene, 3-methyl-1-butene, styrene, 3-butene-1
-Oars and the like.

The unsaturated carboxylic acids and esters thereof described in (f) above include, for example, vinyl acetic acid, crotonic acid, undecylenic acid, ethyl vinyl acetate, propyl vinyl acetate, vinyl butyl acetate, tert-butyl vinyl acetate, ethyl crotonate, Propyl crotonate, butyl crotonate, tert-butyl crotonate, 2-hydroxyethyl crotonate, -3-hydroxypropyl crotonate, -4-hydroxybutyl crotonate, -5-hydroxypentyl crotonate and the like. Can be.

The hydroxyalkyl vinyl ethers of (g) include, for example, hydroxymethyl vinyl ether, hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 5-hydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether, 1,4- Examples include cyclohexane dimethanol vinyl ether.

Examples of the vinyl hydroxycarboxylate (h) include vinyl hydroxypropionate, vinyl hydroxybutyrate, vinyl hydroxypentanoate, and caprolactone-modified vinyl vinyl hydroxypropionate.

The hydroxyalkyl (meth) acrylates (ii) include, for example, hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, polycaprolactone (meth) Acrylate and the like can be exemplified.

Examples of the organic silicon group-containing polymerizable compounds having a hydrolyzable group (nu) include, for example, methacryloxymethyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, and 3-methacryloxypropyltrimethoxysilane. , Vinylmethyldiethoxysilane, vinyltrimethoxysilane, vinylmethyltris (2-methoxyethoxy) silane, vinyltriacetoxysilane, vinyltrimethylsilane, vinylmethyldichlorosilane, vinyltrichlorosilane and the like. Further, a (meth) acrylate compound having an alkoxysilyl group can also be used.

(I) In addition to these, oxirane group-containing vinyl monomers such as allyl glycidyl ether, vinyl glycidyl ether, 3,4-epoxycyclohexylmethyl vinyl ether, and 3,4-epoxycyclohexyl
It is also preferable to adjust the coating composition of the present invention to desired physical properties by using (meth) acrylate or the like or an amino group-containing vinyl monomer such as acrylamide as a copolymer component.

The copolymerizable monomers exemplified above may be used alone or in combination of two or more.
The fluorinated copolymer (B) according to the present invention is a polymer obtained by copolymerizing a monomer mixture comprising a fluoroolefin, a vinyl carboxylate and optionally other monomers, Copolymer wherein the monomer mixture comprises from 20 to 70 mol% of the fluoroolefin (a), from 5 to 75 mol% of the vinyl carboxylate (b) and optionally from 0 to 70 mol% of the other monomer (d) Preferably, the monomer mixture is 20 to 70 mol% of the fluoroolefin (a), 5 to 75 mol% of the vinyl carboxylate (b), 2 to 70 mol% of the hydroxyalkyl allyl ether (c), and optionally More preferably, it is a copolymer comprising 0 to 70 mol% of the other monomer (d).

If the amount of the fluoroolefin is less than 20 mol%, the weather resistance of the coating film is inferior, and if it exceeds 70 mol%, copolymerization becomes difficult, which is not preferable. If the carboxylic acid vinyl ester is less than 5 mol%, the solubility in a solvent is low, resulting in a paint having poor coating operability. If it exceeds 75 mol%, the weather resistance of the coating film is poor, which is not preferable. The copolymerization of hydroxyalkyl allyl ether is optional,
If the amount is less than mol%, curing of the coating film may not be sufficiently performed. If the amount exceeds 70% by mol, the weather resistance of the coating film is poor, which is not preferable. Other optional components may be appropriately adjusted within a range that does not significantly change the properties of the paint and the coating film.

The molecular weight (number average molecular weight in terms of polystyrene) of the fluorinated copolymer (B) is from 1,000 to 300,0.
00, preferably 2,000 to 50,000. If the molecular weight is less than 1,000, the mechanical strength and weather resistance of the coating film are poor, and if it exceeds 300,000, it becomes difficult to form a smooth coating film, which is not preferable.

In producing the fluorinated copolymer (B), a method of polymerizing a monomer mixture containing a fluoroolefin and a vinyl carboxylate as essential components may be carried out in the presence of a conventional radical polymerization initiator. It can be obtained by copolymerizing the monomer mixture in a solvent.

The polymerization temperature in the polymerization reaction is -30 to 10
0 ° C, preferably 0-90 ° C, is suitable. Typical examples of the radical polymerization initiator include the following. For example, acetyl peroxide,
Acyl peroxides such as benzoyl peroxide, ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide, hydroperoxides such as hydrogen peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, dialkyl peroxides such as -tert-butyl peroxide, alkyl peroxyesters such as tert-butylperoxypivalate, tert-butylperoxypivalate, azobisisobutyronitrile, azobisisovaleronitrile Azo compounds and persulfates such as ammonium persulfate and potassium persulfate. If necessary, a reducing agent such as an organic amine or sodium pyrosulfite can be used in combination.

As the organic solvent used for the polymerization reaction, for example, toluene, xylene, solvesso (Exxon Chemical Co., Ltd.)
Co., Ltd.), non-aqueous solvents such as mineral spirits, alcohol solvents such as methanol, ethanol and butanol, ether solvents such as dimethyl ether, diethyl ether and tetrahydrofuran, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone Solvents, ester solvents such as ethyl acetate, butyl acetate, etc., alkylene glycol solvents such as ethyl cellosolve, butyl cellosolve, cellosolve acetate, non-protons such as N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxime A system solvent can be used.

A block copolymer or a graft copolymer (A) comprising a polysiloxane group-containing polymer portion, which is another main component of the present invention, and a polymer portion comprising poly (meth) acrylate or polyester. Is disclosed in Japanese Patent Publication No. Sho 60-30715, Polymer Journal, 52 (8),
465-471 (1995) and the like. Examples thereof include polysiloxane group-containing graft copolymers and block copolymers.

More specifically, for example, the following general formula (1)

[0034]

Embedded image

(Wherein R ¹ is a hydrogen atom or a methyl group,
R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are the same or different and each is a methyl group, an ethyl group or a phenyl group;
M is an integer of 1 or more, and 3 to 1,0
00 is preferable, and 10 to 500 is more preferable. A) a reaction product produced by a copolymerization reaction of an acrylic modified silicone and an ester of (meth) acrylic acid represented by the general formula (2):

[0036]

Embedded image

(Where X is —COOH or —OH,
R ² , R ³ , R ⁴ and R ⁵ are the same or different and each is a methyl group, an ethyl group or a phenyl group; n is an integer of 0 to 3; m is an integer of 1 or more; 000 is preferable, and 10 to 500 is more preferable. )), A polycondensation reaction product of a modified silicone having a functional group at both terminals and a bifunctional hydrocarbon compound.

As the (meth) acrylic acid ester as a copolymer component used in the copolymerization reaction of the acrylic-modified silicone represented by the general formula (1), methyl (meth) acrylate, ethyl (meth) acrylate, Propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, -tert- (meth) acrylate
Butyl, cyclohexyl (meth) acrylate, (meth)
2-ethylhexyl acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate,
Nonyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and the like, and comonomers include acrylic acid, methacrylic acid, styrene, α-methylstyrene, and vinylpyridine. Can be These may be used in combination of two or more.

The copolymerization method is not particularly limited, but it can be obtained, for example, by reacting the modified silicone represented by the general formula (1) with a (meth) acrylic acid ester by heating in a solvent.

On the other hand, examples of the bifunctional hydrocarbon compound used for the polycondensation reaction of the modified silicone represented by the general formula (2) include terephthalic acid, isophthalic acid, adipic acid, polyethylene glycol, polytetramethylene glycol, Cyclohexane dimethanol and the like.

The polycondensation reaction method is not particularly limited. For example, the modified silicone represented by the general formula (2) and the bifunctional hydrocarbon compound may be mixed with a catalyst such as Ti (OBu) ₄ and (C ₁₀ H _12). 150) _{-3 in} the presence of a stabilizer such as ₃ P
This is performed by heating to a temperature of about 00 ° C.

The block copolymer or graft copolymer (A) according to the present invention has a polysiloxane group-containing polymer portion / polymer portion composed of poly (meth) acrylate or polyester in a weight ratio of 5 / 95-90 / 10
And preferably 10/90 to 85/15. When the weight ratio of the polysiloxane group-containing polymer portion is less than 5, the water repellency of the coating film is not sufficiently exhibited, and when it exceeds 90, the miscibility with the fluorinated copolymer (B) is poor. The molecular weight (number average molecular weight in terms of polystyrene) is from 500 to 200,000, and from 1,000 to
50,000 is preferred. If it is less than 500, the water repellency becomes insufficient, and if it exceeds 200,000, the miscibility after the fluorinated copolymer (B) is poor, which is not preferable.

The coating composition of the present invention comprises a block copolymer comprising a polysiloxane group-containing polymer portion obtained as described above and a polymer portion comprising poly (meth) acrylate or polyester. It can be obtained by mixing the graft copolymer (A) and the fluorinated copolymer (B) comprising a fluoroolefin unit, a carboxylic acid vinyl ester unit and optionally other monomer units in an organic solvent.

In the coating composition of the present invention, a block copolymer or a graft copolymer (A) comprising a polysiloxane group-containing polymer portion and a polymer portion comprising a poly (meth) acrylate or a polyester is used. The mixing ratio with the fluorocopolymer (B) comprising a fluoroolefin unit, a carboxylic acid vinyl ester unit and optionally other monomer units is based on 100 parts by weight of (B) and (A)
Is from 0.01 to 30 parts by weight, preferably from 0.05 to 30 parts by weight.
5 parts by weight. If the amount is less than 0.01 part by weight, the water repellency of the coating film, which is the object of the invention, is not sufficiently exhibited, and if it exceeds 30 parts by weight, the smoothness of the coating film is lost, which is not preferable.

The amount of the organic solvent may be an appropriate amount so as to have a desired viscosity and solid content as a usual paint or coating composition. As the organic solvent, it is possible to use the same organic solvents as described above. For example, toluene, xylene, solvesso
(Manufactured by Exxon Chemical Co., Ltd.), non-aqueous solvents such as mineral spirits, alcohol solvents such as methanol, ethanol, butanol, ether solvents such as dimethyl ether, diethyl ether, tetrahydrofuran, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc. Ketone solvents, ester solvents such as ethyl acetate and butyl acetate, alkylene glycol solvents such as ethyl cellosolve, butyl cellosolve, cellosolve acetate, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxime and the like. Various aprotic solvents can be used, and these can be used in combination.

The coating composition obtained as described above can be used as a coating without using a curing agent or by mixing with a curing agent. At this time, as the curing agent, hexamethylene diisocyanate, tolylene diisocyanate, isocyanates such as diphenylmethane diisocyanate, alkylated melamine, methylol melamine, melamine resin such as imino melamine, amino compounds such as urea resin Is valid.

The curing reaction of the coating film can be carried out usually at any temperature in the range of room temperature to 300 ° C., but it can be accelerated by adding a catalyst. Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. In the examples, “parts” means “parts by weight”.

[0048]

【Example】

Reference Example 1 (Production of polysiloxane group-containing graft copolymer (A)) α, ω-dihydroxydimethylpolysiloxane (

[0049]

Embedded image

A mean value of n: 30) To a solution of 220 g and 9.5 g of pyridine in 400 ml of diethyl ether, a 10% diethyl ether solution of 22 g of γ-methacryloxypropyldimethylchlorosilane was gradually added dropwise at room temperature over 20 minutes. did. After completion of the dropwise addition, stirring was continued for 1 hour, and the generated pyridine hydrochloride was separated by filtration. After the filtrate was washed with water and the ether layer was dried, the ether was removed under reduced pressure to obtain 205 g of an acrylic-modified silicone.

Next, the obtained acrylic-modified silicone 4
Parts, 20 parts of methyl methacrylate, 0.46 parts of azobisisobutyronitrile and 50 parts of xylene were placed in a flask equipped with a reflux condenser and a stirrer, and reacted at 80 ° C. for 3 hours in a nitrogen atmosphere. Next, the temperature was raised to 100 ° C., and a mixture of 8 parts of acrylic-modified silicone, 40 parts of methyl methacrylate, 0.9 part of azobisisobutyronitrile, and 100 parts of xylene was added dropwise over 1 hour. After stirring for 3 hours as it was to continue the reaction, the reaction solution was cooled to room temperature and poured into a large amount of hexane. The powdery solid precipitate was washed several times with hexane and dried under reduced pressure to obtain 63.6 g of a solid resin (this resin is referred to as a-1).

The obtained resin had a Si content of 5.1% by weight as determined by a gravimetric method, and an average molecular weight as determined by gel permeation chromatography of 13,000 in terms of polystyrene.

Reference Example 2 (Production of polysiloxane group-containing graft copolymer (A)) 4 parts of acrylic-modified silicone obtained in the same manner as in Reference Example 1, 20 parts of methyl methacrylate, 1 part of methacrylic acid , 0.5 parts of azobisisobutyronitrile, 0.002 parts of t-dodecylmercaptan and 50 parts of xylene were placed in a flask equipped with a reflux condenser and a stirrer, and placed in a nitrogen atmosphere at 70%.
The reaction was carried out at 3 ° C. for 3 hours. Next, the temperature was raised to 100 ° C., and 8 parts of acrylic-modified silicone, methyl methacrylate 40
Part, methacrylic acid 2 parts, azobisisobutyronitrile 1
Part, t-dodecyl mercaptan 0.005 part, xylene 1
00 parts of the mixture was added dropwise over 1 hour. After the stirring reaction was continued for 3 hours, the reaction solution was cooled to room temperature and poured into a large amount of hexane. The powdery solid precipitate was washed several times with hexane and dried under reduced pressure to obtain 67.6 g of a solid resin (this resin is referred to as a-2).

The obtained resin had a Si content of 5.0% by weight determined by a gravimetric method, an average molecular weight determined by gel permeation chromatography of 8,000 in terms of polystyrene, and an acid value of 24.5 mg KOH /. g.

Reference Example 3 (Production of Fluorine-Containing Copolymer (B)) Vinyl pivalate (Vpv) 17 was placed in a stainless steel autoclave equipped with an electromagnetic stirrer.
3.4 parts, 4-allyloxy-1-butanol (HBAE) 104 parts, crotonic acid (CA) 3.5 parts, xylene 290 parts, sodium carbonate 2.2
And 5.5 parts of t-butyl peroxypivalate (t-BPV), and the inside of the autoclave was replaced with nitrogen gas three times. Next, the autoclave was cooled with liquid nitrogen to degas the inside, and 265.3 parts of chlorotrifluoroethylene (CTFE) was introduced.
Thereafter, the temperature was gradually raised in an oil bath, and polymerization was carried out at 55 ° C. for 20 hours. Next, after removing unreacted CTFE and opening the autoclave, the inorganic salt was filtered to obtain a colorless and transparent resin solution having a solid content concentration of 60% by weight.

Reference Example 4 (Production of Acrylic Copolymer) Ethyl acrylate: 18 parts, isobutyl methacrylate: 15 parts, methacrylic acid-2- Ethylhexyl: 15 parts, hydroxyethyl methacrylate: 17
Parts of styrene: 35 parts of a monomer mixture, 2 parts of azobisisobutyronitrile and 60 parts of a mixed solvent of xylene and butyl acetate: 1: 1 (volume ratio): 60 parts as a polymerization initiator, and the mixture was heated to 80 ° C. For 8 hours to obtain a solution of an acrylic copolymer having a nonvolatile content of 63% and an average molecular weight of 26,000.

Example 1 A polysiloxane group-containing graft copolymer (a-
1) 100 parts (as solid content in the solution) of the fluorinated copolymer (B) obtained in Reference Example-3 in 0.5 part, Cymel 303 (melamine resin manufactured by Mitsui Cyanamid Co., Ltd.) 25
Parts, and 1 part of dodecibenzenesulfonic acid was added as a curing catalyst, followed by Solvesso 100 (Exxon Chemical Co., Ltd.).
(Manufactured by Co., Ltd.) to adjust the concentration to obtain a paint. This paint is applied on an aluminum plate by spraying,
For 30 minutes to obtain a coating film of about 30 μm (cured film a′-1).

For the cured film a′-1, the water contact angle (θH
₂ O) and the drop angle (α) of the water droplet were measured (all
The measurement was performed using a measuring device (water contact angle measuring device, water falling angle measuring device) manufactured by Co., Ltd. The same applies hereinafter. ) However, θH ₂ O
= 110 ° and α = 5 °. In addition, an accelerated weathering test (Suga Test Instruments Co., Ltd., Du Panel Weathering Tester 2,000
60 ° gloss retention after 0 hour treatment. The same applies hereinafter. As a result, the gloss retention was 77%.

Example 2 0.5 parts of the polysiloxane group-containing graft copolymer (a-2) obtained in Reference Example 2 was added to the fluorinated copolymer (Reference Example 3) B) 10
0 parts (as solids in solution), Cymel 303-2
After mixing 5 parts and adding 1 part of dodecibenzenesulfonic acid as a curing catalyst, Solvesso 100 was added to adjust the concentration to obtain a paint. This paint was applied on an aluminum plate by a spray method and baked and cured at 140 ° C. for 30 minutes to obtain a coating film of about 30 μm (cured film a′-2).

For the cured film a′-2, the water contact angle (θH
₂ O), was measured water droplet falling angle _{(α), θH 2 O =} 1
00 ° and α = 5 °. Further, as a result of the accelerated weather resistance test, the gloss retention was 80%.

Comparative Example 1 100 parts of the fluorinated copolymer (B) obtained in Reference Example 3 (solution) was added without adding the polysiloxane group-containing graft copolymer obtained in Reference Example 1. 25 parts of Cymel 303 were mixed, 1 part of dodecybenzenesulfonic acid was added as a curing catalyst, and Solvesso 100 was added to adjust the concentration to obtain a paint. This paint was applied on an aluminum plate by a spray method and baked and cured at 140 ° C. for 30 minutes to form a coating film of about 30 μm (cured film b′-1).

For the cured film b′-1, the water contact angle (θH
₂ O), was measured water droplet falling angle _{(α), θH 2 O =} 9
0 ° and α = 10 °. As a result of the accelerated weather resistance test, the gloss retention was 81%.

Comparative Example 2 0.5 part of the polysiloxane group-containing graft copolymer (a-1) obtained in Reference Example 1 was added to the acrylic copolymer 100 obtained in Reference Example-4. Parts (as a solid content in the solution) and 25 parts of Cymel 303 were mixed, and 1 part of dodecibenzenesulfonic acid was used as a curing catalyst.
Then, Solvesso 100 was added to adjust the concentration to obtain a paint. This paint was applied on an aluminum plate by a spray method and baked and cured at 140 ° C. for 30 minutes to form a coating film of about 30 μm (cured film b′-2). When the water contact angle (θH ₂ O) and the water drop falling angle (α) were measured for the cured film b′-2, θH ₂ O = 100 °, α = 14
°. Further, as a result of the accelerated weather resistance test, the gloss retention was 50%.

[0064]

The coating composition of the present invention has the effects of forming a coating film having excellent water repellency in addition to the inherent weather resistance of a fluororesin and maintaining its surface properties for a long period of time.

Claims (4)

[Claims] 1. A polysiloxane group-containing polymer portion and a polysiloxane
A block copolymer or a graft copolymer (A) composed of a polymer portion composed of a (meth) acrylate or a polyester, and a copolymer composed of a fluoroolefin unit, a vinyl carboxylate unit and optionally another monomer unit. A coating composition comprising a fluorine copolymer (B) and an organic solvent. 2. The coating composition according to claim 1, wherein the amount of the block copolymer or the graft copolymer (A) is 0.01 to 30 parts by weight based on 100 parts by weight of the fluorinated copolymer (B). Stuff. 3. A polymer obtained by copolymerizing a monomer mixture comprising a fluoroolefin, a vinyl carboxylate and optionally other monomers, wherein the fluorinated copolymer (B) comprises: The monomer mixture comprises 20 to 70 mol% of a fluoroolefin (a), 5 to 75 mol% of a carboxylic acid vinyl ester (b), 2 to 70 mol% of a hydroxyalkyl allyl ether (c) and another monomer (d)
The coating composition according to claim 1, comprising 0 to 70 mol%. 4. The weight ratio of the block copolymer or the graft copolymer (A) to the polysiloxane group-containing polymer portion / poly (meth) acrylate or polyester portion is 5/95 to 5/95. 90/10 and a molecular weight (number average molecular weight in terms of polystyrene) of 500
The coating composition according to claim 1, wherein the coating composition has a molecular weight of about 200,000.