JPH0335011A - Fluorine-containing copolymer and use thereof - Google Patents

Abstract

PURPOSE:To obtain the title copolymer containing a constituent unit derived from a chlorine-containing fluoroolefin, useful for coating liquid (the polymer solution of organic solvent) rapidly curable at normal temperature, having improved elongation. CONSTITUTION:The aimed copolymer comprising (A) a constituent unit derived from a chlorine-containing fluoroolefin, (B) a constituent unit derived from a hydroxyl group-containing vinyl ether, (c) a constituent unit derived from a vinyl ether not containing hydroxyl group, (D) a constituent unit derived from an organosilicon compound containing an olefinic unsaturated bond and a hydrolyzable group wherein the amount of the component A is 30-70mol%, the total amount of the components B+C is 20-60mol% and the amount of the component D is 1-25mol% based on total number of mols of the components A to D.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a fluorine-containing copolymer that can be dissolved in an organic solvent and rapidly cured at room temperature and has improved elongation, and uses thereof.

Technical background of the invention Weather resistance,
Paints with excellent durability are required, and high-grade exterior paints based on polyester or acrylic are used. but,
Existing paints have a short outdoor service life, and even the above-mentioned high-quality paints lose their aesthetic appearance and substrate protection effect within a few years.

On the other hand, fluoropolymers are extremely stable both thermally and chemically, and have excellent weather resistance, water resistance, chemical resistance, solvent resistance, mold releasability, low friction, and water repellency. Suitable as a surface treatment agent for various substrates. However, conventionally known fluoropolymers suffer from the above-mentioned properties,
It was difficult to form a coating film because it was soluble in organic solvents, making it extremely difficult to use it as a paint. For example, most of the currently known fluoropolymer paints are powder paints, and a small amount of PVdF (polyvinylidene fluoride) is used as an organic solvent-dispersed paint by taking advantage of its ability to dissolve in specific solvents at high temperatures. It's just being told. Moreover, these fluoropolymer paints require baking at a high temperature when forming a film, so their field of use has been limited to areas where heating equipment is available. Furthermore, the presence of heating equipment and the necessity of performing a baking process are not desirable from the viewpoint of the safety of the workers and the environment of the workplace. Therefore, in recent years, attempts have been made to develop fluoropolymers that are solvent-soluble or do not require a baking process at high temperatures.

In light of these current circumstances, we have developed a system that: ■ dissolves in organic solvents at low temperatures, ■ does not require a special hardening agent, ■ hardens at room temperature, and ■ has weather resistance, water resistance, chemical resistance, and resistance after curing. [A] (a) Fluoroolefins, (b) Vinyl ethers, (c) Olefinic unsaturated bonds and hydrolysis. A copolymer substantially consisting of an organosilicon compound having a possible group, wherein (a)
: 30 to 70 mol%, (b) = 20 to 60 mol%, (c
): 1 to 25 mol%, and the number average molecular weight (Mn) measured by [C] gel permeation chromatography is 3000 to 2000
A solvent-soluble fluorine-containing copolymer defined by 00 and a paint obtained by dissolving this fluorine-containing copolymer in an organic solvent are
This is proposed in Japanese Patent Application No. 59-283017.

This fluorine-containing copolymer has extremely excellent properties, but the adhesion between the coating film obtained by dissolving this fluorine-containing copolymer in an organic solvent and coating the base material is Further improvements in performance are desired.

Purpose of the Invention The present invention can be dissolved in an organic solvent, can be rapidly cured at room temperature, and has excellent adhesion between the coating film and the substrate when it is made into a paint and a coating film is formed. The purpose of the present invention is to provide such a fluorine-containing copolymer and its uses.

Summary of the Invention The fluorine-containing copolymer according to the present invention comprises a structural unit (a) derived from a chlorine-containing fluoroolefin, a structural unit (b-1) derived from a hydroxy group-containing vinyl ether, and a structural unit (b-1) derived from a hydroxy group-containing vinyl ether. Contains a structural unit (b-2) derived from vinyl ether and a structural unit (c) derived from an organosilicon compound having an olefinic unsaturated bond and a hydrolyzable group, and constitutes the copolymer (a ), (b-1), (b-2
), (a) is 30 to 70 with respect to the total number of moles of (c)
In the amount of mol%, (b-1) + (b-2) is 20 to 60
In an amount of mol %, (c) is characterized in that it is present in an amount of 1 to 25 mol %.

DETAILED DESCRIPTION OF THE INVENTION The method for producing a fluorine-containing copolymer according to the present invention will be specifically described below.

First, to explain the fluorine-containing copolymer according to the present invention, this fluorine-containing copolymer consists of a structural unit (a) derived from a fluoroolefin containing chlorine, and a structural unit (b-1) derived from a hydroxy group-containing vinyl ether. ), a structural unit (b-2) derived from a vinyl ether containing no hydroxy group, and a structural unit (C) derived from an organosilicon compound having an olefinic unsaturated bond and a hydrolyzable group. has been done. However, within the scope that does not impair the purpose of the present invention, structural units derived from small amounts of other copolymerizable monomer components, such as α-olefins, cycloolefins, carboxylic acid vinyl esters, carboxylic acid allyl esters, etc. It doesn't matter if it contains.

In the fluorine-containing copolymer according to the present invention, the fluoroolefin used to derive the structural unit (a) as described above has at least one fluorine atom and chlorine atom in the molecule, and preferably Preferred are perhaloolefins in which all hydrogen atoms of the olefin are replaced with fluorine atoms, chlorine atoms, and other halogen atoms.

Furthermore, from the viewpoint of polymerizability and properties of the resulting polymer, fluoroolefins having 2 or 3 carbon atoms are preferred.

Specifically, such fluoroolefins include:
The following compounds are used.

CCjl F-CF, CHCρ-CF 2, CCI
-CF 5CCI F-CCI F.

2 CHF-C (1, fluoroolefin having 2 carbon atoms (fluoroethylene) such as CeB6-CCIIF.

CF2CpCF-CF2, CF C1! -CF,CF3CF-CF(1,
2 CF2(l CCI7-CF2, CF2(l CF-CF(1.

CFCfI CFI-CF 1CCg30F! cF2,
2 CF3CF-CM (1.

CCN　F2CF-CHI! .

C (13CF-CHCN, CF2N CF-CF2,
Fluoroolefins having 3 carbon atoms (fluoropropene type) such as CH2B r CF-CC20.

CF3Cl1! -CFCF3, CFz-CFCF2CCDF2, CF2-CFCF2CCg3, CH2-CFCCII2CCg3, CF3 (CF2)2CCD-CF2, CF3 (CF
2) Fluoroolefins having 4 or more carbon atoms such as 3-CCD-CF2.

Among these, as mentioned above, fluoroethylene and fluoropropene are preferred, and chlorotrifluoroethylene (CCN F-CF2) is particularly preferred.

Further, in the present invention, the fluoroolefins may be used alone or in combination of two or more.

In the fluorine-containing copolymer according to the present invention, the vinyl ether used to derive the structural unit (b-1) derived from the above-mentioned hydroxy group-containing vinyl ether includes a vinyl group, an alkyl group, a cycloalkyl group, It is bonded to an aryl group, an aralkyl group, etc. via an ether bond, and further contains a hydroxyl group.

As such hydroxy group-containing vinyl ether,
Specifically, hydroxyalkyl vinyl ether and hydroxyalkylaryl ether are preferred, hydroxyalkyl vinyl ether is more preferred, and hydroxybutyl vinyl ether is particularly preferred.

Furthermore, in the fluorine-containing copolymer according to the present invention, the vinyl ether used to derive the structural unit (b-2) derived from vinyl nythyl that does not contain a hydroxyl group has a vinyl group, an alkyl group, a cyclo Alkyl groups, aryl groups, aralkyl groups, etc. are bonded via ether bonds and do not contain hydroxyl groups.

Examples of such vinyl ethers not containing a hydroxyl group include 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-
Chain alkyl vinyl ethers such as methyl-1-pentyl vinyl ether, cycloalkyl vinyl ethers such as cyclopentyl vinyl ether and cyclohexyl vinyl ether, phenyl vinyl ether, 0-1m-1p
- Aryl vinyl ethers such as tolyl vinyl ether, aralkyl vinyl ethers such as benzyl vinyl ether and phenethyl vinyl ether.

Among these, the number of carbon atoms is preferably 8 or less, preferably 2 to 4.
and a chain alkyl vinyl ether having 5 to 5 carbon atoms.
6 is preferred, and ethyl vinyl ether, propyl vinyl ether, and butyl vinyl ether are more preferred.

Furthermore, in the present invention, the vinyl ether as described above is
In addition to being used alone, they can also be used in combination.

The structural unit (b-1) derived from the above-mentioned hydroxy group-containing vinyl ether accounts for 1 to 35 mol%, preferably 5 to 30 mol% of the total number of moles of (b-1) and (b-2). The structural unit (b-2) derived from a vinyl ether containing no hydroxyl group is the same as that of (b-1) and (b-1).
-2) 65 to 99 mol% of the total number of moles, preferably 7
It is preferably 0 to 95 mol%.

In the fluorine-containing copolymer according to the present invention, the structural unit (c
) is a compound having an olefinic unsaturated bond and a hydrolyzable group in the molecule, specifically, the following - formula (1)
Compounds shown in ~(3) can be exemplified.

R1R25iY1Y2 (1) R' XS i YlY2 (2) R' Si
Y'Y2Y" (3) (wherein, RR2 has an olefinically unsaturated bond and is composed of carbon, hydrogen, and optionally oxygen, each of which is the same or different group. X is an olefinically unsaturated bond Yl, Y2, and Y3 are each the same or different hydrolyzable groups.) R1 or R2 is specifically an organic group having no
lyl), butenyl, cyclohexenyl, cyclopentagenyl, etc., and terminal olefinically unsaturated bond groups are particularly preferred. Moreover, R1 or R2 has an ester bond of a terminal unsaturated acid, CH-CH-0(CH2)3CM-C(CH3)Coo(CH)2
It can also be a group such as 23 CH-C(CH)Coo (CH2) 23 (CH2)3 CH2C(CH3)C00CH2CH2-〇H. Among these, it is preferable that R and R2 do not contain oxygen and are composed of carbon and hydrogen, and a vinyl group is particularly suitable.

Specifically, X is a monovalent hydrocarbon group such as methyl, ethyl, propyl, tetradecyl, octadecyl, phenyl, benzyl, tolyl, etc., and these groups are
It may also be a halogen-substituted hydrocarbon group.

3 Yl, Y 1Y specifically includes an alkoxy group such as methoxy, ethoxy, butoxy, and methoxyethoxy, an alkoxyalkoxy group, an acyloxy group such as formyloxy, acetoxy, and propionoxy, an oxime, for example, 10N-C(CH3) 2 , 10N11llCHCH2C2H5 and 10N-C (
C6H5) 2, and any other hydrolyzable organic group.

In the present invention, the organosilicon compound has the general formula (3
) is preferable, and organosilicon compounds in which the groups y 1 y 2 y 3 are the same are particularly preferable. Among these, R1 is a vinyl group,
Organosilicon compounds in which Y -Y3 is an alkoxy group or an alkoxyalkoxy group are particularly preferred, such as vinyloxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(
Methoxyethoxy)silane and the like are preferred. Furthermore, vinylmethyljethoxysilane, vinylphenyldimethoxysilane, etc. can be used similarly.

In the fluorine-containing copolymer according to the present invention, the content ratio of the heptanomer components (a) to (C) is 30 to 70 moles based on the total number of moles of (a) to (C). %, preferably in an amount of 40 to 60 mol%, (b-1) + (b-2
) is in an amount of 20 to 60 mol%, preferably 20 to 50 mol%, and (C is preferably in an amount of 1 to 25 mol%, preferably 3 to 20 mol%).

The molecular weight of the fluorine-containing copolymer according to the present invention is a number determined by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent and monodisperse polystyrene of known molecular weight as a standard substance. The average molecular weight (Mn) is usually in the range of 3,000 to 200,000.

Such a fluorine-containing copolymer according to the present invention can be used, at room temperature, for example, aromatic hydrocarbons such as benzene, toluene, and xylene, ketones such as acetone and methyl ethyl ketone, diethyl ether, dipropyl ether, and ethyl cellosolve. It dissolves in ethers, esters such as ethyl acetate and butyl acetate, alcohols such as n-butanol and ethanol, and halogenated hydrocarbons such as trichloromethane, dichloroethane and chlorobenzene.

Therefore, a coating composition can be prepared by dissolving the above-mentioned fluorine-containing copolymer in the above-mentioned organic solvent.

When preparing a coating composition from the above-mentioned fluorine-containing copolymer, toluene, xylene, butyl acetate, methyl isobutyl ketone, ethyl or methyl cellosolve, celloacetate, or a mixture thereof may be used as the organic solvent. is preferred.

Such a fluorine-containing copolymer has a hydrolyzable organic group derived from the groove bottom unit (c) derived from an organosilicon compound, so when it comes into contact with moisture, the molecular chains of the polymer are A cross-linking reaction occurs and hardening occurs. Therefore, as a matter of course, moisture in the atmosphere can also cause crosslinking. It is clear that this fluorine-containing copolymer can be crosslinked even when used alone, but when used as a paint, it is necessary to use silanol condensation so that the fluorine-containing copolymer film applied to the base material cures quickly. The catalyst may be added to the coating composition in advance or before coating. in this case,
When an organic solvent solution containing a fluorine-containing copolymer and a silanol condensation catalyst is applied to a substrate, a curing reaction occurs as the organic solvent evaporates and comes into contact with moisture in the air, resulting in film hardening.

As the silanol catalyst, known ones can be used, and specifically, dibutyltin dilaurate, dioctyltin dilaurate, stannous acetate, stannous octoate, lead naphthenate, iron 2-ethylhexanoate, and naphthene. Carboxylic acid metal salts such as cobalt acid, organic bases such as ethylamine, hexylamine, dibutylamine, piperidine, and acids such as inorganic acids and organic fatty acids are used. Among these, alkyltin carbon salts such as dibutyltin dilaurate, dioctyltin dilaurate, diptyltin dioctoate, and dibutyltin diacetate are preferred.

The crosslinking reaction of the fluorine-containing copolymer according to the present invention proceeds satisfactorily at room temperature, that is, around room temperature (0 to 40°C), but the reaction may be carried out under heating if necessary.

When the fluorine-containing copolymer according to the present invention is used as a paint, it is preferable to use it in a one-component form as described above, and this paint composition can be used with a brush or with a brush like a normal liquid paint. It can be applied to the surface of base materials such as metal, wood, plastic, ceramic, paper, and glass using a spray roller coater.

The cured film has excellent weather resistance, chemical resistance, solvent resistance, water resistance, and low friction, as well as excellent transparency, gloss, and elongation.

The fluorine-containing copolymer after curing has excellent elongation properties as described above. Here, the elongation properties of the fluorine-containing copolymer were evaluated as shown in Examples.

The fluorine-containing copolymer according to the present invention has each of the above-mentioned monomers, namely, a chlorine-containing fluoroolefin, a hydroxy group-containing vinyl ether, a hydroxy group-free vinyl ether, an olefinic unsaturated bond, and a hydrolyzable group. It can be produced by copolymerizing an organosilicon compound in the presence of a known radical initiator. Here, each component of fluoroolefin, vinyl ether, and organosilicon compound must all be present. For example, copolymerization does not occur with only fluoroolefin and organosilicon compound, but by adding vinyl ether, each of the above components are copolymerized.

When producing such a fluorine-containing copolymer, various known radical initiators can be used. Specifically, organic peroxides, organic bersesters such as benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(peroxybenzoate) hexyne-3,1 ,4-bis(ter
t-butylperoxyisopropyl)benzene, lauroyl peroxide, tert-butyl peracetate,
2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3,2,5-dimethyl-2,5-di(
tert-butylperoxy)hexane, tert-butylberbenzoate, tert-butylperphenylacetate, tert-butylberisobutyrate, t
ert-butylberu 8ee-octoate, tert
-butyl perbivalate, cumyl verpivalate, ta
Other azo compounds such as azobis-isobutylnitrile, dimethylazoisobutyrate, etc. are used, such as rt-butyl perdiethyl acetate. Among these, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3,2,5-dimethyl-2,5-
Di(tert-butylperoxy)hexane, 1.4-
Dialkyl peroxides such as bis(tert-butylperoxyisopropyl)benzene are preferred.

The copolymerization reaction as described above is preferably carried out in a reaction medium consisting of an organic solvent. Examples of such organic solvents include aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as n-hexane, cyclohexane, and n-heptane, and chlorobenzene, bromobenzene, iodobenzene, and O-bromotoluene. Halogenated aromatic hydrocarbon, tetrachloromethane, 1,1.1
-) Halogenated aliphatic hydrocarbons such as dichloroethane, tetrachloroethylene, l-chlorobutane, etc. can be used.

In the copolymerization reaction as described above, the radical initiator is added at a molar ratio of 1 to the total number of moles of monomers in the solvent as described above.
It is preferable to add in the range of 0-2 to 2×10=. The polymerization temperature is -30 to 200°C, preferably 2
0-100℃, polymerization pressure 0-100kg/cd-01
Preferably it is 0 to 50 kg/c-G.

In the present invention, when producing a fluorine-containing copolymer using a fluoroolefin containing chlorine as the fluoroolefin, a chlorine scavenger is added to the system during the polymerization reaction and/or during the purification of the obtained copolymer. It is desirable to have it exist.

As such a chlorine scavenger, the following compounds can be used.

(I〉M AR(OH)2x+3y-2゜(A) ・
ax y
zH20 (where M is Mg, Ca or Zn, A is co or HPO4, x,
y and z are positive numbers, and a is O or a positive number. ) complex compound.

Specifically, the following compounds are used as the composite compound represented by (a).

Mg AN (OH) Co ・4H20
B 2 18 3 Mg l (OH) Co ・5H208
2203 Mg Al (OH) Co ・4H20
52143 Mg AD (OH) Co ・4H20
102223 Mg A [(OH) HPO-4H20B
2 1B 4 Ca A II (0)1) CO◆4
)1206 2 18 3 Zn AN (OH) CO・4HO8818
32 The complex compound represented by (a) may be a compound that is not exactly represented by the above formula, for example, Mg
It may also be a compound in which part of OH9 in AD (OH) .3H20 is replaced with COa. Further, water of crystallization may be removed from these compounds.

In such a complex compound, M is Mg and A
Compounds in which is CO3 are preferred.

(b) Basic compounds of alkaline earth metals Examples of basic compounds of alkaline earth metals include MgO, Ca
Alkaline earth metal oxides such as O, Mg (OH)
, alkaline earth metal hydroxides such as Ca(OH)2,
Alkaline earth metal carbonates such as MgCOSCaCO3 are used.

The basic compounds of alkaline earth metals as mentioned above are (M
gCO) ・Mg (OH) ◆5 H234
20 may be used as a double salt, and the water of crystallization may be removed from these compounds.

Among these basic compounds of alkaline earth metals,
Mg-containing compounds are preferred.

(c) Epoxy group-containing compounds Examples of epoxy group-containing compounds include silicon-containing epoxy compounds such as γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and trimethylolpropane polysilane. Aliphatic epoxy compounds such as glycidyl ether and neopentyl glycol diglycidyl ether are used.

Among these, silicon-containing epoxy compounds such as γ-glycidoxypropyltrimethoxysilane are preferred.

Among the chlorine scavengers mentioned above, chlorine scavengers that are inorganic compounds react faster with chlorine (hydrochloric acid) than chlorine scavengers that are organic compounds, and they do not dissolve in polymerization or purification systems. It is preferably used because it is easy to remove from the system. Particularly preferred are the composite compounds shown in (a).

By making the above-mentioned chlorine scavenger present during the polymerization reaction, during purification of the obtained copolymer, or both, coloring of the obtained fluorine-containing copolymer can be effectively prevented. In particular, by allowing a chlorine scavenger to be present in the system during the polymerization reaction, coloring of the resulting fluorine-containing copolymer can be effectively prevented.

In addition, when the obtained fluorine-containing copolymer is purified with alcohol or the like, a chlorine scavenger is present in the system, and this fluorine-containing copolymer is dissolved in an organic solvent such as toluene to form a paint. When this paint is applied to a base material such as metal to form a coating film, it is possible to effectively prevent rust from forming on the base material.

When such a chlorine scavenger is used during the polymerization reaction, it is preferably used in an amount of 0.5 to 100 g, preferably 1 to 70 g, per mole of chlorine atoms contained in (a) fluoroolefin.

In addition, when using a chlorine scavenger during purification, the amount of chlorine scavenger used is 0.5 to 100 tr per 100 g of the obtained fluorine-containing copolymer.
Preferably 1-70. It is preferable to use an amount of .

As mentioned above, the fluorine-containing copolymer of the present invention is most suitable for use as a coating composition in the form of a solution dissolved in various organic solvents. It may be blended into a colored paint, and if necessary, various additives commonly blended with synthetic resins may be blended. Further, the above-described fluorine-containing copolymer may be used as a modifier for resins having alkoxysilyl groups or silanol groups, such as silylated acrylic resins, silicone paints, and silylated polyolefins.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 The interior of a stainless steel autoclave with an internal volume of 1.511 mm and a stirrer was replaced with nitrogen, and 180 ml of benzene was added under a nitrogen stream.
, 115.1 g of ethyl vinyl ether (EVE),
Hydroxybutyl vinyl ether (lIyBVE) 2
4. 4 g, t'J metho t-cyhinylsilane (
TMVS) 43. 6 g, synthetic hydrotalcite (Mg i (OH), Co3-3.51120
) Powder Sintering 4.32 13.0 g of the finished product (IIT) was charged. Thereafter, 257 g of chlorotrifluoroethylene (CTFE) was introduced into the autoclave, and the temperature was raised to 65°C.

Add 7.6 g of dilauroyl peroxide to this and 120 c of benzene.
An initiator solution dissolved in c was fed over a period of 4 hours. After further reacting at 65° C. for 6 hours, the autoclave was cooled with water to stop the reaction.

After cooling, unreacted monomers were expelled, the autoclave was opened, and the reaction solution was taken out into a 1.5 g eggplant flask.

Add to this 210g of xylene, 120g of methanol, 5HT
13. Add or and further incubate at 50°C for 1.5 hours at 60°C.
The mixture was heated under stirring for 1.5 hours.

After the treatment, residual monomers and solvent were distilled off under reduced pressure using an evaporator, and then 550 g of xylene was added and stirred to form a homogeneous solution.

This solution was filtered to remove SHT and concentrated under reduced pressure to obtain 322 g of a colorless and transparent polymer (1).

The number average molecular weight of the obtained polymer by GPC was 10.
It was 300.

In addition, the composition analysis of this copolymer was carried out by elemental analysis and NMR.
CTFE/EV E/Hy
BVE/TMV S-49/39/6/6 (molar ratio).

Example 2 In Example 1, tolumethoxyvinylsilane (TMV
S) instead of methyldimethoxyvinylsilane (MDMV
Copolymer (II) was synthesized in the same manner as in Example 1 using S).

The number average molecular weight of the obtained polymer by GPC was 9.7.
It was 00.

In addition, the composition analysis of this copolymer was carried out by elemental analysis and NMR.
CTFE/EVE/H3/B
The molar ratio was VE/MDMVS-51/35/7/7.

Comparative Example 1 The inside of a stainless steel autoclave with an internal volume of 1.5p and equipped with a stirrer was replaced with nitrogen, and 180ml of benzene was added under a nitrogen stream.
Ethyl vinyl ether (EVE) 106 g, n-butyl vinyl ether (BYE) 21, Of, trimethoxyvinyl silane (TMVS) 62.2 g, synthetic hydrotalcite (Mg4.3^fI(OH) Co ・3
．． 5II□0) 13.0 g of powdered calcined product 2 13 3 (sHT) was charged. Thereafter, 257 g of chlorotrifluoroethylene (CTFE) was introduced into the autoclave, and the temperature was raised to 65°C.

Add 7.6 g of dilauroyl peroxide to this and 120 c of benzene.
An initiator solution dissolved in c was fed over a period of 4 hours. After further reacting at 65° C. for 6 hours, the autoclave was cooled with water to stop the reaction.

After cooling, the unreacted upper polymer was expelled, the autoclave was opened, and 1. The reaction solution was taken out into a 1" eggplant-shaped flask.

To this, xylene 21 Or, methanol 120g 5HT
13. Osr was added, and the mixture was heated at 50° C. for 1.5 hours and then at 60° C. for 1.5 hours while stirring.

After the treatment, residual monomers and solvent were distilled off under reduced pressure using an evaporator, and then 550 g of xylene was added and stirred to form a homogeneous solution.

This solution was filtered to remove SHT and concentrated under reduced pressure to obtain 366 g of a colorless and transparent polymer (III).

The number average molecular weight of the obtained polymer by GPC is to,
It was ooo.

In addition, the composition analysis of this copolymer was carried out by elemental analysis and NMR.
CTFE/EVE/BVE/
TMVS-50/37/6/7 (molar ratio).

Example 3 35.5 parts by weight of copolymer (1) obtained in Example 1, 1.7 parts by weight of tetramethyl orthosilicate oligomer, 1.7 parts by weight of methyl orthoformate, 29 parts by weight of titanium oxide, 32 parts by weight of xylene. A paint (1) consisting of .1 part by weight was prepared.

On the other hand, a 6.3% by weight xylene solution of di-n-butyltin dilaurate was prepared as a curing catalyst liquid.

In addition, galvanized steel sheets (SPG) specified in JIS G 3302
), epoxy paint, Marine SC (Mitsui Metal Paint Chemicals ■)
A coated board was prepared by exposing the specimens at three levels with an exposure period of 10, 20, and 30 days.

To 100 parts by weight of coating liquid (1), add 3.0 parts of the above curing catalyst liquid.
Mix 6 parts by weight and apply 1 part of this mixture on the above painted board.
It was applied using a 00 μm applicator. After this was exposed outdoors for one week, a cellophane tape test was conducted.

The results are shown in Group 1.

Example 4 In the same manner as in Example 3, the copolymer (II) obtained in Example 2 was made into a paint, applied, and subjected to a cellophane tape test.

The results are shown in Table 1.

Comparative Example 2 The copolymer (III) obtained in Comparative Example 1 was made into a paint, applied, and subjected to a cellophane tape test in the same manner as in Example 3.

The results are shown in Table 1.

RJlsK5400 was applied to the coating surface of the painted plate applied to the steel plate.
Cuts were made in accordance with the 1979 Paint General Test Method 6, 15th Base Test. Next, apply a piece of cellophane adhesive tape with a width of 20III11 to the surface of the paint film at the second stitch, rub it strongly with a spatula of width 7111 to bring the tape into close contact with the paint film surface, and then quickly move the cellophane tape vertically upward. I pulled it up and peeled it off. This cellophane tape was adhered and peeled off a total of four times from each direction of the four sides of the base grains, and the number of base grains that remained without being removed was determined, and the test results were expressed in terms of the number.

Claims (2)

[Claims] (1) A structural unit (a) derived from a fluoroolefin containing chlorine, a structural unit (b-1) derived from a hydroxy group-containing vinyl ether, and a structural unit (b-2) derived from a vinyl ether not containing a hydroxy group. and a structural unit (c) derived from an organosilicon compound having an olefinic unsaturated bond and a hydrolyzable group, and (a), (b-1), (b- 2)
, relative to the total number of moles of (c), (a) is in an amount of 30 to 70 mol%, (b-1) + (b-2) is in an amount of 20 to 60 mol%, and (c) is A fluorine-containing copolymer, characterized in that the fluorine-containing copolymer is present in an amount of 1 to 25 mol%. (2) A coating composition prepared by dissolving the fluorine-containing copolymer according to claim 1 in an organic solvent.