JP2725726B2 - Method for producing fluorinated copolymer - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for producing a fluorine-containing copolymer which is free of coloring, can be dissolved in an organic solvent, and can be rapidly cured at room temperature.

Technical background of the invention and its problems In the exterior fields of buildings, vehicles, ships, aircrafts, etc., paints having excellent weather resistance and durability are required, and high-grade polyester or acrylic exterior paints are used. . However, the outdoor service life of existing paints is short, and even the above-mentioned high-grade paints lose their aesthetics and substrate protection in a few years.

On the other hand, fluoropolymers are extremely stable both thermally and chemically and are excellent in weather resistance, water resistance, chemical resistance, solvent resistance or mold release, low friction, and water repellency, It is suitable as a surface treatment agent for various substrates. However, conventionally known fluorine-containing polymers suffer from the above-mentioned properties, are hardly soluble in an organic solvent, are difficult to form a coating film, and are very difficult to use as a paint. For example, currently known fluoropolymer coatings are often powder coatings, and use the property that PVdF (polyvinylidene fluoride) dissolves in a specific solvent at high temperatures as an organic solvent-dispersed coating. It is only used. Moreover, these fluoropolymer coatings require high-temperature baking at the time of film formation, and their use has been limited to places where heating equipment can be used. Further, the presence of the heating equipment and the necessity of performing the baking process are not preferable from the viewpoint of safety of persons engaged in the work and the environment of the workplace. Therefore, in recent years, attempts have been made to develop a fluoropolymer which does not require a solvent-soluble or high-temperature baking step.

For example, JP-A-57-34107 discloses a quaternary copolymer consisting of fluoroolefin, cyclohexyl vinyl ether, alkyl vinyl ether and hydroxyalkyl vinyl ether, and this copolymer is soluble in an organic solvent. It is also described that the composition can be cured at room temperature. However, in order to cure this copolymer at room temperature, a melamine-based curing agent and a urea resin-based curing agent are additionally required, and there is a disadvantage that the weather resistance is reduced accordingly. In addition, the glass transition temperature of this copolymer is relatively high at room temperature or higher, that is, at 25 ° C. or higher. Also JP-B-46-39472
Although no actual example is described in the publication, an organosilicon compound having an olefinically unsaturated bond and a hydrolyzable group in PTFE (polytetrafluoroethylene) is used as a radical initiator such as an organic hydroperoxide. Those mechanically treated in the presence have been suggested to crosslink and cure with water at room temperature. However, the fluoropolymer produced by this method is a polymer in which an organosilicon compound is grafted on PTFE, and is substantially insoluble in an organic solvent.

In view of this situation, the present inventors dissolve at low temperatures in organic solvents, do not require special curing agents for curing, cure at room temperature, and after curing, weather resistance, water resistance, chemical resistance [A] (a) a fluoroolefin, (b) a vinyl ether, (c) an olefinically unsaturated bond and a fluorinated copolymer which is excellent in solvent resistance and low friction property and can be directly polymerized from a monomer component. A copolymer substantially consisting of: an organosilicon compound having a decomposable group, [B] a copolymer (a) based on the total number of moles of (a) to (c) in the copolymer. ): 30-70 mol%, (b): 20-60 mol%,
(C): a solvent-soluble fluorine-containing copolymer having a number average molecular weight (n) of from 3000 to 200,000 as determined by gel permeation chromatography, which is from 1 to 25 mol%; A paint obtained by dissolving a fluorine-containing copolymer in an organic solvent,
Proposed in Japanese Patent Application No. 59-263017.

This fluorinated copolymer has extremely excellent properties, but (a) if a fluorinated olefin containing chlorine is used as the fluoroolefin, the resulting fluorinated copolymer will be colored yellow or the like. There was a point. Therefore, there is a problem that a coating film obtained by applying a coating material obtained by dissolving the fluorine-containing copolymer in an organic solvent on a substrate is colored yellow.

An object of the present invention is to solve the above-mentioned problems, and it is free from coloring, and is a fluorocopolymer which can be dissolved in an organic solvent and rapidly cured at room temperature. The purpose of the present invention is to provide a manufacturing method.

SUMMARY OF THE INVENTION The method for producing a fluorocopolymer according to the present invention comprises: (a) a fluoroolefin containing chlorine; (b) a vinyl ether; and (c) an organosilicon compound having an olefinically unsaturated bond and a hydrolyzable group. When producing a fluorinated copolymer by copolymerization, select from the following (a), (b), and (c) in the system during the polymerization reaction and / or during the purification of the obtained copolymer. Characterized in that any one type of chlorine scavenger is present.

(A) M _x Al _y (OH) _{2x + 3y-2z} (A) _z · aH ₂ O (wherein
M is Mg, Ca or Zn, A is CO ₃ or HPO ₄ , x, y, are positive numbers, and a is 0 or a positive number)
(B) a basic compound of an alkaline earth metal, and (c) an epoxy group-containing compound.

In the present invention, when producing the above-mentioned fluorine-containing copolymer, at the time of the polymerization reaction and / or at the time of purification of the obtained copolymer, the specific chlorine scavenger as described above is present in the system. Therefore, a fluorinated copolymer without coloring can be obtained.

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

First, the fluorinated copolymer according to the present invention will be described. This fluorinated copolymer comprises (a) a fluoroolefin containing chlorine, (b) vinyl ether, and (c)
It is a copolymer comprising three types of monomer component units with an organosilicon compound having an olefinically unsaturated bond and a hydrolyzable group. However, a small amount of other copolymerizable monomer components such as α
-Olefins, cycloolefins, carboxylic acid vinyl esters, carboxylic acid allyl esters, and the like may be copolymerized.

The fluoroolefin (a) used in the present invention has at least one or more fluorine and chlorine atoms in the molecule, and preferably, all of the hydrogen atoms of the olefin are fluorine, chlorine and other halogen atoms. Substituted perhaloolefins are preferred. Further, from the viewpoint of polymerizability and properties of the obtained polymer, a fluoroolefin having 2 or 3 carbon atoms is preferable.

As such a fluoroolefin, specifically, the following compounds are used.

CClF = CF ₂ , CHCl = CF ₂ , CCl ₂ = CF ₂ , CClF = CCIF, CHF
= CCl ₂ , CCl ₂ = Fluoroolefins having 2 carbon atoms such as CClF (fluoroethylene-based).

CF ₂ ClCF = CF ₂ , CF ₃ CCl = CF ₂ , CF ₃ CF = CFCl, CF ₂ ClCCl =
CF ₂ , CF ₂ ClCF = CFCl, CFCl ₂ CF = CF ₂ , CCl ₃ CF = CF ₂ , CF ₃
CF = CHCl, CCIF ₂ CF = CHCl, CCl ₃ CF = CHCl, CF ₂ ICF = C
F ₂ , CH ₂ BrCF = CCl ₂ or other fluoroolefin having 3 carbon atoms (fluoropropene-based).

CF ₃ CCl = CFCF ₃ , CF ₂ = CFCF ₂ CClF ₂ , CF ₂ = CFCF ₂ CCl ₃ ,
CH ₂ = CFCCl ₂ CCl ₃ , CF ₃ (CF ₂ ) ₂ CCl = CF ₂ , CF ₃ (CF ₂ ) ₃ C
Cl = CF 4 or more carbon atoms of the fluoroolefin such as _2.

Of these, fluoroethylene and fluoropropene are preferred as described above, and chlorotrifluoroethylene (CClF = CF ₂ ) is particularly preferred.

Further, in the present invention, the fluoroolefin may be used alone, or two or more kinds may be used as a mixture.

The vinyl ether (b) used in the present invention is a compound in which a vinyl group and an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group and the like are ether-bonded.

As such vinyl ethers, specifically, ethyl vinyl ether, propyl vinyl ether, isopropyl vinyl ether, butyl vinyl ether, tert-
Chain alkyl vinyl ethers such as butyl vinyl ether, pentyl vinyl ether, hexyl vinyl ether, isohexyl vinyl ether, octyl vinyl ether, 4-methyl-1-pentyl vinyl ether, cycloalkyl vinyl ethers such as cyclopentyl vinyl ether and cyclohexyl vinyl ether, and aryl vinyl ethers such as phenyl vinyl ether And aralkyl vinyl ethers such as benzyl vinyl ether and phenethyl vinyl ether.

Among them, particularly those having 8 or less carbon atoms, preferably 2 to
A chain alkyl vinyl ether having 4 and 5 carbon atoms;
Preferred are cycloalkyl vinyl ethers that are
Further, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, and cyclohexyl vinyl ether are preferred.

In the present invention, the vinyl ethers described above may be used alone or as a mixture of two or more.

The organosilicon compound (c) used in the present invention is a compound having an olefinically unsaturated bond and a hydrolyzable group in the molecule, and specifically has the following general formulas (1) to (1).
The compound shown in (3) can be exemplified.

R ¹ R ² SiY ¹ Y ² (1) R ¹ XSiY ¹ Y ² (2) R ¹ SiY ¹ Y ² Y ³ (3) (wherein, R ¹ and R ² have an olefinically unsaturated bond. ,
These are the same or different groups each consisting of carbon, hydrogen and optionally oxygen. X is an organic group having no olefinically unsaturated bond, and Y ¹ , Y ² , and Y ³ are the same or different hydrolyzable groups. R ¹ or R ² is specifically vinyl, allyl (ally
l), butenyl, cyclohexenyl, cyclopentadienyl and the like, and particularly preferably a terminal olefinically unsaturated group. R ₁ or R ₂ has an ester bond of a terminal unsaturated acid And the like. Among them, R ₁ and R ₂ are preferably composed of carbon and hydrogen without oxygen, and a vinyl group is most preferred.

X is, specifically, methyl which is a monovalent hydrocarbon group,
Ethyl, propyl, tetradecyl, octadecyl, phenyl, benzyl, tolyl and the like, and these groups may be halogen-substituted hydrocarbon groups.

Y ¹ , Y ² and Y ³ are specifically an alkoxy group such as methoxy, ethoxy, butoxy, methoxyethoxy,
Alkoxyalkoxy group, formyloxy, acetoxy,
An acyloxy group such as propionoxy, oxime for example _{-ON = C (CH 3) 2} , -ON = CHCH 2 C 2 H 5 and _{-ON = C (C 6 H 5} ) 2 and the like, may be any other hydrolysis Organic group.

In the present invention, the organosilicon compound is preferably a compound represented by the general formula (3) as described above, and particularly preferably an organosilicon compound in which the groups Y ¹ , Y ² and Y ³ are the same. Among them, R ¹ is a vinyl group, and Y ^{1 to} Y ³
Is particularly preferably an organosilicon compound in which an alkoxy group or an alkoxyalkoxy group is used, for example, vinyloxypropyltrimethoxysilane, vinyltrimethoxysilane,
Vinyl triethoxysilane, vinyl tris (methoxyethoxy) silane, and the like are preferable. Further, vinylmethyldiethoxysilane, vinylphenyldimethoxysilane and the like can be used in the same manner.

In the fluorinated copolymer according to the present invention, (a) to (c)
(A) is 30 to 70 mol%, preferably 40 to 40 mol%, based on the total number of moles of (a) to (c).
(B) is an amount of 20 to 60 mol%, preferably 20 to 50 mol%, and (c) is an amount of 1 to 25 mol%, preferably 3 to 20 mol%. Desirably.

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

Accordingly, 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 fluorinated copolymer as described above, as an organic solvent, toluene, xylene,
It is preferable to use butyl acetate, isobutyl methyl ketone, methyl cellosolve, ethyl cellosolve or a mixture thereof.

Since such a fluorinated copolymer has a hydrolyzable organic group derived from the organosilicon compound (c), a crosslinking reaction occurs between molecular chains of the polymer upon contact with moisture. To cure. Therefore, crosslinking may naturally occur due to atmospheric humidity. It is obvious that crosslinking of this fluorinated copolymer proceeds even when used alone, but when it is used as a paint, silanol condensation is performed so that the fluorinated copolymer film applied to the base material is rapidly cured. The catalyst can be added to the coating composition in advance, or can be added immediately before coating. In this case, when an organic solvent liquid containing a fluorinated copolymer and a silanol condensation catalyst is applied to a substrate, the organic solvent evaporates and comes into contact with moisture in the air, and at the same time, a curing reaction occurs, and film curing occurs. .

As the silanol catalyst, known catalysts can be used. Specifically, dibutyltin dilaurate, dioctyltin dilaurate, stannous acetate, stannous octoate, lead naphthenate, iron 2-ethylhexanoate, naphthene Metal salts of carboxylic acids such as cobalt acid, organic bases such as ethylamine, hexylamine, dibutylamine and piperidine,
Acids such as inorganic acids and organic fatty acids are used. Of these, alkyltin carboxylate, for example, dibutyltin diurarate, dioctyltin dilaurate, dibutyltin dioctoate, and dibutyltin diacetate are preferred.

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

When using the fluorine-containing copolymer according to the present invention as a paint, like a normal liquid paint, brush, spray, roller coater and the like, metal, wood, plastic, ceramic, paper, glass and the like substrate surface. Can be applied. After curing, the coating is excellent in weather resistance, chemical resistance, solvent resistance, water resistance, heat resistance, low friction, transparency, gloss,
Excellent elongation.

In the present invention, when producing the above-mentioned fluorine-containing copolymer, a chlorine scavenger is present in the system during the polymerization reaction and / or during the purification of the obtained copolymer. Specifically, when the above-mentioned (a) chlorine-containing fluoroolefin, (b) vinyl ether and (c) organosilicon compound are copolymerized, the reaction system was obtained in the presence of a chlorine-trapping agent. When purifying the fluorinated copolymer with an organic solvent such as alcohol, a chlorine scavenger is preferably present in the system.

The following compounds can be used as the chlorine scavenger.

(A) M _x Al _y (OH) _{2x + 3y-2z} (A) _z · aH ₂ O (wherein
M is Mg, Ca or Zn, A is CO ₃ or HPO ₄ , x, y, z are positive numbers, and a is 0 or a positive number. ).

As the composite compound represented by (a), specifically,
The following compounds are used.

_{Mg 6 Al 2 (OH) 16} CO 3 · 4H 2 O Mg 8 Al 2 (OH) 20 CO 3 · 5H 2 O Mg 5 Al 2 (OH) 14 CO 3 · 4H 2 O Mg 10 Al 2 (OH) 22 _{CO 3 · 4H 2 O Mg 6} Al 2 (OH) 16 HPO 4 · 4H 2 O Ca 6 Al 2 (OH) 16 CO 3 · 4H 2 O Zn 6 Al 6 (OH) 16 CO 3 · 4H 2 O the ( The complex compound represented by a) may be a compound that is not exactly represented by the above formula, for example, Mg
Some of the _{2 Al (OH) 9 · 3H} 2 O of OH may be a compound substituted with CO _3. In these compounds, water of crystallization may be removed.

Among such complex compounds, M is Mg and A
Is preferably CO ₃ .

(B) Basic compounds of alkaline earth metals Examples of basic compounds of alkaline earth metals include alkaline earth metal oxides such as MgO and CaO, and Mg (OH)
₂ , alkaline earth metal hydroxides such as Ca (OH) ₂ , MgC
Alkaline earth metal carbonates such as O ₃ and CaCO ₃ are used.

The alkaline earth metal basic compound as described above,
It may be a double salt such as (MgCO ₃ ) ₄ .Mg (OH) ₂ .5H ₂ O, and these compounds may have water of crystallization removed.

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

(C) Epoxy group-containing compound Epoxy group-containing compounds include silicon-containing epoxy compounds such as γ-glycidoxypropyltrimethoxysilane and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and trimethylolpropane polyglycidyl. An aliphatic epoxy compound such as ether or neopentyl glycol diglycidyl ether is used.

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

Among the chlorine scavengers as described above, the chlorine scavenger that is an inorganic compound, compared to the chlorine scavenger that is an organic compound,
It is preferably used because it quickly reacts with chlorine (hydrochloric acid) and is not dissolved in a polymerization system or a purification system, so that it is easily removed outside the system. Particularly, the composite compound shown in (a) is preferable.

Coloring of the obtained fluorine-containing copolymer can be effectively prevented by making the above-mentioned chlorine scavenger dependent on the polymerization reaction and / or the purification of the obtained copolymer. In particular, by causing the chlorine scavenger to be present in the system during the polymerization reaction, the resulting fluorocopolymer can be effectively prevented from being colored.

In addition, by causing a chlorine scavenger to be present in the system when purifying the obtained fluorinated copolymer with alcohols or the like, the fluorinated 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 a metal to form a coating film, it is possible to effectively prevent rust from being generated 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 1 mol of chlorine atoms contained in the fluoroolefin (a).

When the chlorine scavenger is used at the time of purification, it is preferably used in an amount of 0.5 to 100 g, preferably 1 to 70 g, based on 100 g of the obtained fluorine-containing copolymer.

When the obtained fluorinated copolymer is purified with an organic solvent, it is preferable to use alcohols as the organic solvent, and the alcohols include methanol, ethanol, propanol, isopropanol, n-butanol and iso-ethanol. -Butanol, tert-butanol and the like are used.

In the present invention, a fluorinated copolymer can be produced according to a conventionally known method except that the above-mentioned chlorine scavenger is present in the polymerization reaction system and / or the purification system.
That is, the fluorinated copolymer according to the present invention can be produced by copolymerizing each of the monomers (a) to (c) as described above in the presence of a known radical initiator.
Here, each of the components (a) to (c) needs to be present. For example, copolymerization does not occur only with the component (a) and the component (c), but the component (b) is added. Thereby, each component of (a), (b) and (c) is copolymerized.

In producing such a fluorine-containing copolymer, various known radical initiators are used. Specifically, organic peroxides, organic peresters such as benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (peroxybenzoate) hexyne-3,1 , 4-bis (tert-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, t
ert-butyl perbenzoate, tert-butyl perphenyl acetate, tert-butyl perisobutyrate, te
Other azo compounds such as rt-butyl per-sec-octoate, tert-butyl perpivalate, cumyl perpivalate, tert-butyl perdiethyl acetate, etc., such as azobis-isobutylnitrile and dimethylazoisobutyrate, are used. Among them, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-
2,5-di (tert-butylperoxy) hexyne-3,2.5
Dialkyl peroxides such as -dimethyl-2,5-di (tert-butylperoxy) hexane, 1,4-bis (tert-butylperoxyisopropyl) benzene are preferred.

The above copolymerization reaction is preferably performed in a reaction medium comprising 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; chlorobenzene, bromobenzene, iodobenzene, and o-protoluene. Halogenated aromatic hydrocarbons, halogenated aliphatic hydrocarbons such as tetrachloromethane, 1,1,1-trichloroethane, tetrachloroethylene, 1-chlorobutane and the like can be used.

In the copolymerization reaction as described above, the radical initiator is used in a solvent as described above in a molar ratio to the total number of moles of the monomer.
It is preferable that the addition be performed in the range of 10 ^{-2 to} 2 × 10 ^-3 .
The polymerization temperature is from -30 to 200C, preferably from 20 to 100C.

 With the fluorine-containing copolymer according to the present invention, an organic pigment or the like
In order to further improve the affinity, the molecules of the fluorinated copolymer
A carboxyl group can be introduced into the chain. concrete
Include unsaturated carboxylic acids or their derivatives
What is necessary is just to graft-polymerize to a polymer. For such purpose
Unsaturated carboxylic acids include acrylic acid,
Tacrylic acid, α-ethylacrylic acid, maleic acid, fuma
Oleic acid, itaconic acid, citraconic acid, tetrahydrophthalate
Luric acid, methyltetrahydrophthalic acid, endocis-bis
Clos [2,2,1] hept-5-ene-2,3-dicarboxylic acid
(Nadic acid ), Methyl-endocis-bicyclo [2,
2,1] hept-5-ene-2,3-dicarboxylic acid (methylna
Zic acid ) And unsaturated carboxylic acids such as
Acid halides, amides, imides, acid anhydrides, esters
That is, maleenyl chloride, maleimide, maleic anhydride,
Citraconic anhydride, monomethyl maleate, maleic acid
And dimethyl.

The fluorinated copolymer thus obtained is purified by treating it with an organic solvent such as an alcohol in which a chlorine scavenger is present as described above, and then removing the solvent and the residual monomer. A polymer is obtained. Thereafter, the obtained fluorinated copolymer is dissolved in an organic solvent such as xylene, and the solid is filtered. After adjusting the concentration of the organic solvent, a fluorinated copolymer paint is obtained.

As the application field of the fluorine-containing copolymer according to the present invention,
As described above, it is most suitable to use it as a coating composition in a form dissolved in various organic solvents. In this case, a pigment or a dye may be blended into the coating composition to form a colored paint, and if necessary, various additives usually blended in a synthetic resin may be blended. Further, the above-mentioned fluorinated copolymer may be used as a modifier for a resin having an alkoxysilyl group or a silanol group such as a silylated acrylic resin, a silicon-based paint, or a silylated polyolefin.

Effect of the Invention In the present invention, when producing the above-mentioned fluorine-containing copolymer, at the time of polymerization reaction and / or at the time of purification of the obtained copolymer, the above-mentioned specific chlorine scavenger is added to the system in the system. Because it is present, a fluorinated copolymer without coloring can be obtained.

〔Example〕

Hereinafter, the content of the present invention will be described with preferred examples, but the present invention is not limited to these examples unless otherwise specified, and any embodiment is possible without impairing the object of the present invention. .

Example 1 The inside of a 1.5-liter stainless steel autoclave equipped with a stirrer was purged with nitrogen, and under a nitrogen stream, 180 ml of benzene, 106 g of ethyl vinyl ether (EVE), 21.0 g of n-butyl vinyl ether (BVE), and trimethoxyvinylsilane (TMVS) 6
2.2 g, synthetic hydrotalcite (Mg _4.5 Al ₂ (OH) ₁₃ CO ₃
13.5 g of a calcined product (SHT) of 3.5H ₂ O) powder was charged. Thereafter, 257 g of chlorotrifluoroethylene (CTFE) was introduced into the autoclave, and the temperature was raised to 65 ° C.

An initiator solution obtained by dissolving 7.6 g of dilauroyl peroxide in 120 cc of benzene was fed to the mixture obtained as described above over 4 hours. After further reaction 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-liter eggplant-shaped flask.

Xylene 210 g, methanol 120 g, SHT13.
After adding 0 g, the mixture was heated at 50 ° C. for 1.5 hours and further stirred at 60 ° C. for 1.5 hours under stirring.

After the treatment, the residual monomer and the solvent were distilled off under reduced pressure using an evaporator, and then 550 g of xylene was added, followed by stirring 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.

The number average molecular weight of the obtained polymer by GPC is 10,000.
Met.

The composition of this copolymer was analyzed by elemental analysis and NMR.
Was performed using CTFE / EVE / BVE / TMVS = 50/37/6
/ 7 (molar ratio).

The degree of coloration of the thus obtained fluorinated copolymer was measured by measuring the absorbance of light having a wavelength of 420 nm, which is a complementary color of yellow, as described below, and it was 6.4.

<Method of measuring absorption of light having a wavelength of 420 nm> 100 parts by weight of a fluorinated copolymer is dissolved in 100 parts by weight of xylene to prepare a resin solution.

Meanwhile, Multipurpose Recording Spectrophotometer MPS
-2000 (manufactured by Shimadzu Corp.), and set the wavelength of xylene to 4 in advance.
Measure the absorbance of 20nm light beforehand. Next, the absorption of the above resin solution was examined, and the value obtained by subtracting the xylene absorption from this was defined as the absorbance of the resin.

The schematic relationship between the absorbance in this measurement and the visual determination of the degree of coloring (Gardner No.) is shown below.

Gardner No. 1 absorbance 50 × 10 ^-3 Gardner No. 2 absorbance 100 × 10 ^-3 Example 2 A copolymer was obtained in the same manner as in Example 1 except that the amount of the hydrochloric acid scavenger was changed. Table 1 shows the amount of the hydrochloric acid scavenger and the degree of coloring of the polymer.
Shown in

Example 3 After the polymerization reaction in Example 1, the operation after opening the autoclave was performed as follows.

210 g of xylene was added, the residual monomer and the solvent were distilled off under reduced pressure by an evaporator, and then 550 g of xylene was added, followed by stirring to form a homogeneous solution. Filter this solution
The SHT was removed and the mixture was concentrated under reduced pressure to obtain a copolymer.

 Table 1 shows the coloring degree of the obtained polymer.

Examples 4 to 8 Copolymers were obtained by changing the type and amount of the hydrochloric acid scavenger in Example 1 and the amount of alcohol added during purification. Table 1 shows the type and amount of the hydrochloric acid scavenger, the amount of the added alcohol, and the coloring degree of the obtained copolymer.

Example 9 Using the same polymerization apparatus as in Example 1, the inside of the apparatus was replaced with nitrogen, and under a nitrogen stream, 180 ml of benzene, 106 g of ethyl vinyl ether (EVE), and 21.0 of n-butyl vinyl ether (BVE).
g, triethoxyvinylsilane (TMVS) 79.9 g, and synthetic hydrotalcite (Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ · 3.5 H ₂ O) powder fired product (SHT) 13.0 g were charged. Thereafter, 257 g of chlorotrifluoroethylene (CTFE) was introduced into the autoclave, and the temperature was raised to 65 ° C.

An initiator solution obtained by dissolving 7.6 g of dilauroyl peroxide in 120 cc of benzene was fed to the mixture obtained as described above over 4 hours. After further reaction 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-liter eggplant-shaped flask.

To this reaction solution, 210 g of xylene, 173 g of ethanol, SHT1
3.0 g was added, and the mixture was heated at 50 ° C. for 1.5 hours and further stirred at 60 ° C. for 1.5 hours under stirring.

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

This solution was filtered to remove SHT, and concentrated under reduced pressure to obtain 406 g of a polymer.

 Table 1 shows the degree of coloring of the copolymer.

Example 10 Using the same polymerization apparatus as in Example 1, the inside of the apparatus was replaced with nitrogen, and under a nitrogen stream, 180 ml of benzene, 106 g of ethyl vinyl ether (EVE), and 21.0 n-butyl vinyl ether (BVE).
g, 3-vinyloxypropyltrimethoxysilane (VoPTM
S) 86.6 g, synthetic hydrotalcite (Mg _4.5 Al ₂ (OH) ₁₃
13.0 g of a calcined product (SHT) of powdered CO ₃ · 3.5H ₂ O) was charged.
Thereafter, 257 g of chlorotrifluoroethylene (CTFE) was introduced into the autoclave, and the temperature was raised to 65 ° C.

To the mixture thus obtained, an initiator solution obtained by dissolving 7.6 g of dilauroyl peroxide in 120 cc of benzene was fed over 4 hours. After further reaction 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-liter eggplant-shaped flask.

To this reaction solution, xylene 210 g, methanol 120 g, SHT1
3.0 g was added, and the mixture was heated at 50 ° C. for 1.5 hours and further stirred at 60 ° C. for 1.5 hours under stirring.

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

This solution was filtered to remove SHT, and concentrated under reduced pressure to obtain 448 g of a polymer.

 Table 1 shows the degree of coloring of the copolymer.

Comparative Example 1 The same polymerization apparatus as in Example 1 was used, and the inside of the apparatus was replaced with nitrogen.
g, 62.2 g of trimethoxyvinylsilane (TMVS). Then, 257g of chlorotrifluoroethylene (CTFE)
Was introduced into an autoclave, and the temperature was raised to 65 ° C.

To the mixture thus obtained, an initiator solution obtained by dissolving 7.6 g of dilauroyl peroxide in 120 cc of benzene was fed over 4 hours. After further reaction at 65 ° C. for 6 hours, the autoclave was cooled with water to stop the reaction.

After cooling, the unreacted monomer was expelled, the autoclave was opened, and the reaction solution was taken out into a 1.5-liter eggplant-shaped flask.
The residual monomer and the solvent were distilled off under reduced pressure using an evaporator to obtain 380 g of a copolymer.

 Table 1 shows the coloring degree of the obtained copolymer.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C08F 230/08 C08F 230/08

Claims (3)

(57) [Claims] 1. A fluorine-containing copolymer is produced by copolymerizing (a) a chlorine-containing fluoroolefin (b) vinyl ether and (c) an organosilicon compound having an olefinically unsaturated bond and a hydrolyzable group. At the time of the polymerization, at the time of the polymerization reaction and / or at the time of purification of the obtained copolymer, one type of chlorine scavenger selected from the following (a), (b) and (c) is present in the system. A method for producing a fluorine-containing copolymer, characterized by: (a) M _x Al _y (OH) _{2x + 3y-2z} (A) _z · aH ₂ O (wherein
M is Mg, Ca or Zn, A is CO ₃ or HPO ₄ , x, y and z are positive numbers and a is 0 or a positive number) (b) alkaline earth (C) Epoxy group-containing compounds. 2. The method according to claim 1, wherein the chlorine scavenger is used in an amount of 0.5 to 1 based on 1 mol of chlorine atoms contained in the fluoroolefin during the polymerization reaction.
The method for producing a fluorocopolymer according to claim 1, wherein the fluorocopolymer is used in an amount of 00g. 3. The process for producing a fluorine-containing copolymer according to claim 1, wherein the chlorine scavenger is used in an amount of 0.5 to 100 g with respect to 100 g of the obtained fluorine-containing copolymer during purification. Method.