JP2551116B2 - Method for producing fluorine-containing copolymer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a fluorinated copolymer containing a carboxyl group, which is useful as a raw material for a fluororesin coating material.

[Conventional technology and its problems]

When a vinyl ether having a carboxyl group and a fluoroolefin are copolymerized, a fluororesin having a carboxyl group can be produced, but it is difficult to synthesize a vinyl ether having a carboxyl group. For example,
When trying to synthesize a vinyl ether having a carboxyl group by reacting a hydroxyalkyl vinyl ether with a dibasic acid anhydride (half-esterification), the carboxyl group and the vinyl group react and are cyclized in the molecule. I can't get it.

Accordingly, a fluorinated copolymer containing a carboxyl group can be produced, for example, by producing a copolymer of vinyl ether containing a hydroxyl group and a fluoroolefin, and then producing a copolymer of the hydroxyl group contained in the copolymer and a dibasic acid anhydride. Reaction (half esterification) (Japanese Patent Publication Sho 61)
-49323 gazette). However, in this method, since half-esterification is carried out after the copolymerization, there is a problem that it is difficult to use an inexpensive alcohol or the like which reacts with a dibasic acid anhydride as a solvent for the copolymerization.

The present inventors have made extensive studies on a method for producing a vinyl ether containing a carboxyl group, and as a result, when a hydroxyalkyl vinyl ether and a dibasic acid anhydride are reacted with each other, if a basic compound is allowed to exist in the system, an intramolecular ring That the carboxyl group of the obtained vinyl ether takes the form of the salt of the basic compound, the stability is improved, and the yield is significantly improved when it is copolymerized with the fluoroolefin. I found it. As the carboxyl group-containing vinyl monomer, a half-esterified product of allyl alcohol and a dibasic acid anhydride or a monovinyl ester of a dibasic acid anhydride can also be used.

By the way, when polymerizing a carboxyl group-containing fluorine-containing copolymer useful as such a general aqueous paint or electrodeposition paint, it is necessary to use a solvent which is soluble in water or has excellent dispersibility as a polymerization solvent. .

Among such solvents, amide-based solvents such as dimethylformamide and dimethylacetamide and ester-based solvents such as methyl cellosolve acetate generate miscellaneous ions in aqueous solution, impairing the stability of the copolymer when it is solubilized, or forming it. The appearance of the coating film may cause fire and cissing. In addition, alcohol solvents such as methanol, ethanol, and isopropanol weaken the stability of vinyl ether monomers by the action of their hydroxyl groups, and also lead to a decrease in the polymerization rate, resulting in the same coating as amide and ester solvents. A film defect occurs. Furthermore, gelation occurs when a ketone solvent such as acetone or methyl ethylene ketone is used alone. Such a decrease in coating film performance becomes more remarkable when the fluoropolymer is used as an electrodeposition coating material.

[Means for solving the problem]

 The present invention has been made to solve such problems.
And (A) a hydroxy group-containing vinyl monomer, and (B) formula (Ia): CH₂= CHOR¹OC (= O) R²C (= O) O M  (Ia) (In the formula, R¹Is a divalent aliphatic group having 2 to 10 carbon atoms, R²Is
Formula (i): CHX¹ _pCX² _{2 q} (I) [wherein X¹Is a hydrogen atom or an alkyl having 1 to 3 carbon atoms.
Lu group, X²Is a hydrogen atom or an alkyl having 1 to 3 carbon atoms
Group, p and q are 0 or an integer of 1 to 11
A group represented by
(Ii): CH_{2 r}CX³= CH_s (Ii) [In the formula, r is 0 or an integer of 1 to 3, and s is an integer of 1 to 3.
Number, X³Is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms
A group represented by the formula (iii):(Where R⁷Is- (CHX^Four _tGroup (however, X^FourIs a hydrogen atom
Or an alkyl group having 1 to 3 carbon atoms, t is an integer of 1 to 4
, -CH₂CH = CHCH₂-Group,OrA group represented by the formula (iv):(Where R⁸Is CHX^Five _uGroup (where X is a hydrogen atom or
Is an alkyl group having 1 to 3 carbon atoms, u is an integer of 3 to 4
Yes) or CX⁶= CX⁷ _vGroup (however, X⁶And X⁷Are the same or different
A hydrogen atom or an alkyl group having 1 to 3 carbon atoms, v
Represents an integer of 2 to 3], a group represented by the formula:
(V): -C (= CH₂) -CH₂A group represented by-(v) or a formula (vi):A group represented by M Is an alkali metal ion) or formula (Ib): CH₂= CHOR¹OC (= O) R²C (= O) O ・ HY  (Ib) (In the formula, R¹And R²Is the same as above, Y Is a nitrogen atom
Or a compound containing a phosphorus atom and having a pKa of 6 to 1
2 represents the monovalent ion of a monofunctional basic compound that is 2.
Vinyl ether in which the carboxyl group represented by
(Hereinafter referred to as vinyl ether (Ia) or (Ib)) and formula (II): CH₂= CHOR¹OC (= O) R²C (= O) OH (II) (In the formula, R¹And R²Is the same as above)
Vinyl ether having a carboxyl group (hereinafter referred to as vinyl
Ether (II)), vinyl ether
(Ia) or (Ib) is 1 mol% of vinyl ether (II)
A vinyl ether monomer composition containing the above, or
Or formula (III):(Where Y¹, Y²And Y³The same or different
Hydrogen atom or an alkyl group having 1 to 6 carbon atoms, a is 0 or
An integer from 1 to 6, R²Is the same as above)
And (C) a fluoroolefin are copolymerized with a ketone solvent having 3 to 20 carbon atoms.
Formula (IV):(Where Y^FourIs an alkyl group having 1 to 8 carbon atoms, Y^FiveIs hydrogen
Atom or methyl group, l is 0 or an integer of 1 to 20
Alcohol mixed with alcohol solvent
The molar ratio of solvent / hydroxy group-containing vinyl monomer is 1 /
Characterized by using a solvent of 10 to 10/1 as a polymerization solvent
And a method for producing a fluorine-containing copolymer.

[Preferred Embodiment] Hydroxy group-containing vinyl monomer (A) used in the present invention
As, 4-hydroxybutyl vinyl ether, 2-
Hydroxyethyl vinyl ether, 3-hydroxy-n
-Propyl vinyl ether, 2-hydroxy-iso-propyl vinyl ether, 2-hydroxy-2-methylethyl vinyl ether, 2-hydroxy-1,1 dimethyl vinyl ether, 4-hydroxycyclohexyl vinyl ether, 3-hydroxycyclohexyl vinyl ether, 2-hydroxycyclohexyl vinyl ether Four
-Hydroxybenzooxy vinyl, 2-hydroxyethyl methacrylate, 2-hydroxypropyl α-chloroacrylate, allyl alcohol and the like can be mentioned.

 Among the components (B) used in the present invention, vinyl ether mono
As described above, the mer composition is a vinyl ether (II) unit.
The storage stability is improved at each stage compared to when it is used alone.
You. The reason is stable vinyl ether (Ia) or
By making (Ib) coexist with 1 mol% or more of (II),
H that promotes the cyclization of vinyl ether (II) Concentration in the system
It is estimated that this is because the

In the vinyl ether monomer composition, the vinyl ether (Ia) or (Ib) is a hydroxyalkyl vinyl ether represented by the formula: CH ₂ = CHOR ¹ OH (wherein R ¹ is the same as above), the formula: Wherein R ² is the same as described above, and an alkali metal compound or a compound containing a nitrogen atom or a phosphorus atom and having a pKa (acid dissociation index at 25 ° C. in water) By reacting 6 to 12 monofunctional basic compounds (hereinafter simply referred to as bases when the two are not distinguished).

Specific examples of the hydroxyalkyl vinyl ether which is a raw material of this production method include 4-hydroxybutyl vinyl ether, 2-hydroxyethyl vinyl ether, 3-hydroxy-n-propyl vinyl ether, 2-hydroxy-iso-propyl vinyl ether, and 2-hydroxy-vinyl vinyl ether.
2-methylethyl vinyl ether, 2-hydroxy-1,
Examples thereof include 1-dimethylethyl vinyl ether, 4-hydroxycyclohexyl vinyl ether, 3-hydroxycyclohexyl vinyl ether, 2-hydroxycyclohexyl vinyl ether, and 4-hydroxybenzooxyvinyl.

R ² contained in the dibasic acid anhydride and the vinyl ether (Ia) or (Ib) or (II) is represented by the formula (i): CHX ¹ _p CX ² _{2 q} (i) [wherein, X ¹ is A hydrogen atom or an alkyl group having 1 to 3 carbon atoms, X ² is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, p and q are 0 or an integer of 1 to 11 (however, they cannot be 0 at the same time) A group represented by the formula], CH _{2 r} CX ³ = CH _s (ii) [wherein r is 0 or an integer of 1 to 3, s is an integer of 1 to 3 and X ³ is A group represented by a hydrogen atom or an alkyl group having 1 to 3 carbon atoms], formula (iii): [In the formula, R ⁷ is-(CHX ⁴ _t group (however, X ⁴ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, t is an integer of 1 to 4), -CH ₂ CH = CHCH ₂ -Group, Or A group represented by the formula (iv): [In the formula, R ⁸ is a CHX ⁵ _u group (provided that X is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and u is an integer of 3 to 4) or a CX ⁶ = CX ⁷ _v group (provided that X ⁶ and X ⁷ are the same or different and each is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, v
Represents an integer of 2 to 3]], a group represented by the formula (v): -C (= CH ₂ ) -CH _2- (v) or a formula (vi): And the like.

Specific examples of dibasic acid anhydrides include maleic anhydride, succinic anhydride, methylsuccinic anhydride, phthalic anhydride, adipic anhydride, glutaric anhydride, glutaconic anhydride, itaconic anhydride, 1,8-naphthalic anhydride Acid, citraconic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 4-methyl-1,2-hexanedicarboxylic anhydride, cis-
Examples thereof include 4-cyclohexene-1,2-dicarboxylic acid, 1-cyclohexene-1,2-dicarboxylic anhydride, and an adduct of cyclopentadiene and maleic anhydride by a Diels-Alder reaction.

Generally, the reaction of a hydroxyl compound with a dibasic acid anhydride proceeds according to the following formula in the presence of a basic catalyst.

In this case, it is at most necessary to obtain the target product with a yield of 90% or more.
It is sufficient to use 0.5 mol% (based on dibasic acid anhydride) of the base. However, according to the study of the present inventors, when hydroxyvinyl ether having high cation reactivity is used as the hydroxyl compound, the reaction cannot be carried out as described below unless the base is present, and the desired product cannot be obtained. If the degree is too low, the yield of the target product is low and the stability is poor, so that it is not suitable as a monomer for polymerization.

However, the presence of the above-mentioned base in an amount of 1 mol% or more results in a yield of more than 90%, and furthermore, the obtained product becomes stable, and a decrease in the yield can be prevented. The reason is,
It is considered that the base prevents the reaction between the carboxyl group and the vinyl group and prevents the cyclization of the vinyl ether (II) produced as described above. The base reacts stoichiometrically with the carboxyl group, but may be present in the reaction system in an amount of 1 mol% or more based on the acid anhydride as described above.
In that case vinyl ether (Ia) or (Ib) and (II)
A mixture of

The monomer composition can also be obtained by adding a base to a mixture of vinyl ether (Ia) or (Ib) and (II) and reacting with vinyl ether (II). The base to be added later may be the same as or different from the base present during the reaction. In this case, vinyl ether (II)
The carboxyl group and the base react with each other stoichiometrically.

As the base, an alkali metal compound and a specific monofunctional basic compound are used as described above.

As the alkali metal compound, a compound of Li, K or Na is preferable, for example, lithium hydroxide, sodium hydroxide, potassium hydroxide, lithium carbonate, sodium carbonate,
Examples include potassium carbonate, sodium methylate, sodium methylate, potassium methylate and the like.

The specific monofunctional basic compound is a compound containing a nitrogen atom or a phosphorus atom as described above,
It is a basic compound having a pKa of 6 to 12, preferably 8 to 11. Those having a pKa in this range have a high salt-forming ability and a large stabilizing effect on vinyl ether (II). That is, a dibasic acid anhydride having a pKa higher than that of the carboxylic acid has a high salt-forming ability, and particularly preferably a dibasic acid anhydride having a pKa of 3 to 8 higher than that of the corresponding carboxylic acid. Suitable one
As the functional basic compound, ammonia, amines,
Examples include phosphines. Specific examples of amines include, for example, methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, 1,2-dimethylpropylamine, 2-ethylhexylamine, tridecylamine, Dimethylamine, diethylamine, di-
n-propylamine, di-isopropylamine, dibutylamine, di-isobutylamine, di-sec-butylamine, di-2-ethylhexylamine, trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, N- Methylbutylamine, N-
Ethylbutylamine, N, N-Dimethylethylamine, N, N
-Dimethylisopropylamine, N, N-dimethyltetradecylamine, N, N-dimethyloctadecylamine, 2
-Methoxyethylamine, 3-ethoxyethylamine,
Cyclohexylamine, N, N-dimethylcyclohexylamine, dicyclohexylamine, benzylamine, N,
N-dimethylbenzylamine, 4-methoxyphenylethylamine, ethanolamine, diethanolamine,
Triethanolamine, isopropanolamine, dimethylethanolamine, pyrrolidine, piperidine, 1-
Methylpiperidine, 4-methylpiperidine, morpholine and the like can be mentioned.

Specific examples of phosphines include, for example, trimethylphosphine, triethylphosphine, tripropylphosphine, tributylphosphine, trioctylphosphine, trilaurylphosphine, tristearylphosphine, dimethylphosphine, diethylphosphine, dibutyl Di- or trialkylphosphines such as phosphine, dioctylphosphine, dilaurylphosphine; tris (3-hydroxypropyl) phosphine, tris (2-cyanoethyl) phosphine, tris (2-methoxyethyl) phosphine, tris ( 2-chloroethyl) phosphine,
Tris (2-methoxycarbonyl) phosphine, tris (2- (2-dimethylaminoethoxy) carbonyl)
Di- or tri-substituted alkyl phosphines such as phosphine, tris (2-ethoxycarbonyl) phosphine, bis (3-hydroxypropyl) phosphine and bis (2-cyanoethyl) phosphine; dicyclopentylphosphine, dicyclohexylphosphine, tris Alicyclic phosphines such as cyclopentylphosphine and tricyclohexylphosphine; triphenylphosphine, tris (4-methylphenyl)
Di- or triarylphosphines such as phosphine, diphenylphosphine, bis (4-methylphenyl) phosphine; tribenzylphosphine;
Di- or tri-aralkylphosphines such as triphenethylphosphine, dibenzylphosphine and diphenethylphosphine; phosphines having a phosphorus atom in the ring such as tetramethylenephosphine and tetramethylene-methylphosphine; diphenyl Examples thereof include phosphines such as methylphosphine, diphenylethylphosphine and phenyldiethylphosphine in which two or three different organic groups are bonded to phosphorus atoms. A tertiary amine is particularly preferable.

The reaction temperature is generally -80 to 100C, preferably 0 to 50C.
Is. A solvent is usually used, but it can be carried out without using it. Solvents can be used except for alcohols that react with the dibasic acid anhydride, but ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone cause a decrease in reactivity of the raw materials and a coloring of the reaction mixture. Not preferred. The amount of the base used is usually 0.01 to 1.2 with respect to the above dibasic acid anhydride, preferably
It is 0.05 to 1.0 (however, molar ratio).

Examples of the other carboxyl group-containing vinyl monomer as the component (B) include monomers represented by the formula (III). Specific examples include dicarboxylic acid monoallyl ester and dicarboxylic acid monomethallyl ester synthesized from allyl alcohol or methallyl alcohol and the above dibasic acid anhydride.

In the production method of the present invention, when a hydroxy group-containing vinyl monomer (A), a carboxyl group-containing vinyl monomer (B), and a fluoroolefin (C) are copolymerized, a ketone solvent and the above formula are used as a polymerization solvent. It is characterized by using a mixed solvent with an alcoholic solvent represented by (IV).

Examples of the ketone solvent include acetone, methylethylketone, methylisobutylketone, dibutylketone, acetylacetone, cyclohexanone and the like, and acetone or methylethylketone, particularly acetone is preferable.

Examples of the alcohol solvent represented by the formula (IV) include methanol, ethanol, isopropanol, and n.
-Butanol, t-butanol, methyl cellosolve, butyl cellosolve, butyl carbitol, methyl carbitol and the like may be mentioned alone or in combination, and methanol, ethanol, isopropanol or n-butanol is preferable.

As described above, gelation occurs when the polymerization is performed using the ketone solvent alone, but gelation does not occur when the ketone solvent and the alcohol solvent are mixed and used. The reason for this is presumed to be that gelation caused by cross-linking of the hydroxy group-containing vinyl monomer (A) and the ketone solvent is prevented by adding the alcohol solvent. However, since the alcohol-based solvent has the above-mentioned drawbacks, the alcohol-based solvent / hydroxy group-containing vinyl monomer (molar ratio) is 1/10 to 10% or less in order to suppress gelation and not exhibit the drawbacks of the alcohol-based solvent. It is used in the range of 10/1, preferably 1/3 to 5/1.

The amount of mixed solvent is usually 4/1 to 1/4 with respect to all monomers.
Is preferred.

When such a mixed solvent is used as a polymerization solvent, it does not adversely affect each monomer, the polymerization yield is excellent, the obtained polymer solution does not easily contain low molecular weight substances, and the coating properties and coating film physical properties are excellent.

The copolymerization system basically comprises a hydroxy group-containing vinyl monomer (A), a carboxyl group-containing vinyl monomer (B), a fluoroolefin (C), a polymerization solvent and a polymerization initiator. As the polymerization method, emulsion polymerization, suspension polymerization, solution polymerization and the like can be adopted.

The polymerization temperature can be appropriately changed depending on the type of the initiator and the solvent, but is usually −20 to 150 ° C., preferably 5 to 9
It is 5 ° C. The reaction pressure can be appropriately selected, but is usually 0.
~ 50 kg / cm ² G.

Examples of the fluoroolefin (C) include tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, trifluoroethylene, vinylidene fluoride, vinyl fluoride and the like.

In the present invention, the reaction molar ratio of the hydroxy group-containing vinyl monomer (A), the carboxyl group-containing vinyl monomer (B) and the fluoroolefin (C) is usually (A) /
(B) / (C) = 1 to 50/1 to 60/20 to 80.

When a fluorine-containing copolymer is used as the water-soluble paint, it contains 5 to 50 mol% of a hydroxy group-containing vinyl monomer (A), and in order to improve the water solubility of this copolymer, a carboxyl group is used. It is preferable that the contained vinyl monomer (B) is contained in an amount of 5 to 60 mol%, and it is more preferable that the carboxyl group thereof is neutralized by 30% or more (in the case of electrodeposition coating). Examples of the compound used for neutralization include those exemplified as the above base.

When the fluorine-containing copolymer is dissolved in an organic solvent and used as a so-called solvent type coating material, the hydroxy group-containing vinyl monomer (A) is contained in an amount of 2 to 40 mol% and the carboxyl group-containing vinyl monomer (B). The content is 1 to 1 in terms of adhesion to the base material.
15 mol% is preferable, and 2 to 10 mol% is preferable in terms of pigment dispersibility.

In addition to the components (A) to (C), the fluorine-containing copolymer may contain another type of ethylenically unsaturated compound in an amount ratio of 80 mol% or less based on the fluorine-containing copolymer.
Examples of other kinds of ethylenically unsaturated compounds include, for example, the formula: CH ₂ ═CH—OC═O) _k R ³ (wherein R ³ is an aliphatic group having 1 to 17 carbon atoms, and 3 to 17 carbon atoms). And an alkyl vinyl ether or vinyl ester represented by a cycloaliphatic group having 1 to 20 carbon atoms, k is 0 or 1), and specific examples thereof include methyl vinyl ether, ethyl vinyl ether, and n. -Propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, t-butyl vinyl ether, n-
Pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, lauryl vinyl ether, stearyl vinyl ether, 2,2,
2-trifluoroethyl vinyl ether, 2,2,3,3-tetrafluoropropyl vinyl ether, 2,2,3,3,3-pentafluoropropyl vinyl ether, 2,2,3,3,4,4,5,5
-Octafluoropentyl vinyl ether, 2,2,3,3,4,
4,4-heptafluorobutyl vinyl ether, vinyl acetate, propionic acid vinyl ester, butyric acid vinyl ester, pivalic acid vinyl ester, caproic acid vinyl ester, lauric acid vinyl ester, versatic acid vinyl ester, cyclohexanecarboxylic acid vinyl ester, etc. To be

Furthermore, the formula: CH ₂ = CX ⁸ C (= O) O) mR ⁹ (wherein, X ⁸ is a hydrogen atom, a chlorine atom, a fluorine atom, a methyl group or a trifluoromethyl group, R ⁹ is a hydrogen atom, a chlorine atom, And a compound represented by an aliphatic group having 1 to 17 carbon atoms, an alicyclic group having 3 to 17 carbon atoms or a fluoroalkyl group having 1 to 20 carbon atoms, and m represents 0 or 1. Specific examples include ethylene, propylene, 1-butene, isobutene, styrene, vinyl chloride, vinylidene chloride, isobutyl acrylate, methyl acrylate,
Ethyl methacrylate, 2,2,3,3,3-pentafluoropropyl α-fluoroacrylate, 2,2,3,3,4,4,5,5,6,
6,7,7-dodecafluoropentyl α-trifluoromethyl acrylate, cyclohexyl acrylate, 2,2,3,
3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,
Examples include 14,14,15,15,15-nonacosafluoropentadecyl acrylate, octyl α-chloroacrylate, and octadecyl acrylate.

Further, a compound represented by the formula: CH ₂ = CHCH ₂ X ⁹ (wherein, X ⁹ represents a chlorine atom or an aliphatic oxy group having 1 to 8 carbon atoms) can also be used, and specific examples thereof include allyl chloride. , Allyl methyl ether, allyl isopropyl ether, allyl octyl ether and the like.

If necessary, a small amount of a polyvalent metal (for example,
Mg, Ca, Zn, Al, etc.) or polyfunctional compounds containing a nitrogen atom or a phosphorus atom (for example, alkyldiamine,
Polyvinylamines such as alkyltriamines, polyphosphines such as alkyldiphosphines and alkyltriphosphines) and vinyl ether (II) may be present as copolymer components such as divinyl ether and trivinyl ether. Ai can be used for applications such as matting by partial gelation.

Examples of the polymerization initiator include persulfates (ammonium persulfate, potassium persulfate, etc.), persulfates and sulfites (potassium sulfite, sodium sulfite, etc.), or acidic sulfites (potassium acid sulfite, sodium acid sulfite, etc.). Redox initiators, organic peroxides (diisopropyl peroxydicarbonate, tert-butyl peroxybutyrate, benzoisoperoxide, isobutyryl peroxide, etc.), azo compounds (azobisisobutyronitrile, etc.), etc. be able to. The amount of the initiator used is 0.
It is 001 to 5% by weight, preferably 0.05 to 2.0% by weight.

The operating method of the production method of the present invention is not particularly limited, and batch type, semi-continuous type, continuous type and the like can be adopted.

Next, the present invention will be described based on examples, but the present invention is not limited to only these examples.

Reference Example 1 In a 1000 ml flask, anhydrous 1,2-cyclohexanedicarboxylic acid (anhydride) 405 g (2.63 mol) and acetone 40
Add a solution consisting of g and add triethylamine (base: pKa = 1
0.72) 2.63 g (0.26 mol) was added, and the mixture was stirred with a magnetic stirrer for 5 minutes.

While cooling this mixture with ice water to 0 to 10 ° C, 305 g (2.63 mol) of hydroxybutyl vinyl ether
Was dropped at a rate of 2 g / min.

Fourier transform nuclear magnetic resonance analysis (FT
-NMR, ¹³ C, tetramethylsilane standard) was performed, and the following vinyl ether (I) of the present invention (hereinafter referred to as cHHEM salt) and corresponding free vinyl ether (II) (hereinafter referred to as cH
It was confirmed that HEM) was produced in a yield of about 10/85 (molar ratio). The chemical shift of each carbon atom (labeled with a to m) is shown.

δ (ppm) = 85.6 (a), 151.5 (b), 67.2 (c), 2
5.3-25.6 (d), 62.8 (e), 173.3 (f), 42.9
(G), 27.4 (h), 24.4 (i), 43.5 (j), 176.2
(K), 44.9 (l), 9.1 (m) Reference Example 2 Monomer consisting of cHHEM salt and cHHEM in the same procedure as Reference Example 1 except that the amount of triethylamine in Reference Example 1 was changed to the amount shown in Table 1. A composition was produced. The yields analyzed by FT-NMR are shown in Table 1.

Furthermore, the decomposition rate (%) of the obtained reaction product when stored at 20 ° C and -20 ° C was examined by ¹³ C-NMR.
The results are shown in Table 1.

Reference Example 3 The reaction product obtained under the condition of Experiment No. 4 of Reference Example 2 (cHHEM salt / cHHEM = 0.1 / 84.9: molar ratio) was added with a base shown in Table 2 to convert cHHEM to a cHHEM salt, The decomposition rate was examined in the same manner as in Reference Example 2. The results are shown in Table 2.

As is clear from Table 2, the basic compound having a pKa of less than 6 has a weak basicity and thus has a small contribution to the stabilization of cHHEM.

Example 1 A glass autoclave having a volume of 800 ml equipped with a stirrer was charged with 140.2 g of acetone and 19.8 g of ethanol, solidified with liquid nitrogen, and then deaerated.

Then, 128.2 g of chlorotrifluoroethylene (hereinafter referred to as CTFE) was charged, and the system was heated to 65 ° C. Next, a vinyl ether monomer composition separately obtained in Reference Example 1 (cHHEM salt / cHHEM = 10/85, molar ratio) 72.83 g, hydroxybutyl vinyl ether (hereinafter referred to as HBVE) 49.9 g, and has an alkyl group having 10 carbon atoms. Monomer obtained by mixing 61.4 g of vinyl ester of carboxylic acid [Beova 10 (hereinafter referred to as VA) manufactured by Ciel Chemical Co., Ltd.] and 1.64 g of azobisisobutyronitrile (hereinafter referred to as AIBN), solidifying with liquid nitrogen and degassing. The mixture was continuously charged over 4 hours. The system temperature was maintained at 65 ° C. After the preparation, 65 ℃
The reaction was continued for 16 hours, and a carboxyl group-containing fluorocopolymer was obtained. The yield was 455 g and the copolymer concentration was 64.3%.

Examples 2 to 5 and Comparative Examples 1 to 4 Copolymerization was carried out in the same manner as in Example 1 with the compositions shown in Table 3 to obtain fluorine-containing copolymers. Their yields and copolymer concentrations are shown in Table 3.

The symbols in Table 3 indicate the following compounds, respectively.

EVE: Ethyl vinyl ether AIBN: Azobisisobutyronitol Example 6 The fluoropolymer obtained in Example 1 was diluted with isopropyl alcohol (IPA) until the polymer concentration became 25% by weight. Put 100 g of the obtained varnish in a flask with a stirrer.
10.0 g of MgO was added, and the mixture was stirred at 60 ° C. for 24 hours and then passed through a glass filter for dehalogenation.

The dehalogenated 25% by weight varnish was concentrated under reduced pressure to give a 65% concentration varnish. To 100 parts by weight of this varnish, 3.9 parts by weight of dimethylethanolamine (0.9 equivalents to the acid value of the polymer) was added for neutralization.

Using the obtained partially neutralized varnish, a composition for electrodeposition coating was prepared according to the following formulation.

 Parts by weight Varnish 100 Butyl cellosolve 10 80% Methyl methylolated melamine resin (Melan 620 manufactured by Hitachi Chemical Co., Ltd.).

Solid content 70% by weight) 20 Deionized water 990 Anodized using this composition for electrodeposition coating
6063S aluminum alloy plate (thickness of anodized film 9μ
m) as an object to be coated (anode), applying a coating composition at a temperature of 20 ° C. and a voltage of 140 V for 3 minutes, applying the composition on an aluminum alloy plate, washing with water, and then keeping at 180 ° C. for 30 minutes. Baking and curing to obtain an electrodeposition coating film.

The properties shown in Table 4 were examined for the obtained coating film. The results are shown in Table 4.

(Film Thickness) Film Thickness Gauge (Permscope manufactured by Kett Scientific Research Institute Co., Ltd.)
EW) (unit: μm).

(Gloss) 60 using a gloss meter (VG-2PD manufactured by Nippon Denshoku Industries Co., Ltd.)
The specular reflectance (unit:%) was measured.

(Weather resistance) Weather meter (manufactured by Suga Test Instruments Co., Ltd., due cycle, irradiation 60 minutes / dark 60 minutes, black panel temperature 63 ° C)
Was conducted for 360 hours, and the gloss retention (unit:%) was measured.

(Adhesiveness) 100 cuts of 1 mm square were made on the coating film with a cutter knife, a peeling test was performed 10 times with cellophane adhesive tape, and the number of remaining grids was obtained.

(Boiling resistance) According to JIS H 8602.

(Alkali Resistance after Boiling Water Test) The sample after the boiling water test was immersed in a 1% by weight aqueous solution of sodium hydroxide for 72 hours, and the appearance of the coating film was visually observed to check for blister generation.

(Acid resistance) After dipping in a 5% hydrochloric acid solution for 7 days, the change of the coating film was visually determined.

(Appearance) The appearance of the coating film was visually determined.

(Liquid Stability) The solution was allowed to stand for one month in an atmosphere of 30 ° C., and the change was visually determined.

Examples 7 to 10 and Comparative Examples 5 to 8 Compositions for electrodeposition coating were prepared in the same manner as in Example 6 except that the fluoropolymers produced in Examples 2 to 5 and Comparative Examples 1 to 4 were used. Then, electrodeposition was performed.

 The results are shown in Table 4.

[Effects of the Invention] According to the present invention, it is possible to increase the yield and provide a more homogeneous fluorine-containing copolymer by using a specific polymerization solvent. When such a fluorine-containing copolymer is used as a coating material, a coating film free from cracks and cissing and having excellent weather resistance can be obtained.

Claims (5)

(57) [Claims] 1. A hydroxy group-containing vinyl monomer (A), and (B) formula (Ia): CH₂= CHOR¹OC (= O) R²C (= O) O M  (Ia) (In the formula, R¹Is a divalent aliphatic group having 2 to 10 carbon atoms, R²Is
Formula (i): CHX¹ _pCX² _{2 q} (I) [wherein X¹Is a hydrogen atom or an alkyl having 1 to 3 carbon atoms.
Lu group, X²Is a hydrogen atom or an alkyl having 1 to 3 carbon atoms
Group, p and q are 0 or an integer of 1 to 11
A group represented by
(Ii): CH_{2 r}CX³= CH_s (Ii) [In the formula, r is 0 or an integer of 1 to 3, and s is an integer of 1 to 3.
Number, X³Is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms
A group represented by the formula (iii):(Where R⁷Is- (CHX^Four _tGroup (however, X^FourIs a hydrogen atom
Or an alkyl group having 1 to 3 carbon atoms, t is an integer of 1 to 4
, -CH₂CH = CHCH₂-Group,OrA group represented by the formula (iv):(Where R⁸Is CHX^Five _uGroup (where X is a hydrogen atom or
Is an alkyl group having 1 to 3 carbon atoms, u is an integer of 3 to 4
Yes) or CX⁶= CX⁷ _vGroup (however, X⁶And X⁷Are the same or different
A hydrogen atom or an alkyl group having 1 to 3 carbon atoms, v
Represents an integer of 2 to 3], a group represented by the formula:
(V): -C (= CH₂) -CH₂A group represented by-(v) or a formula (vi):A group represented by M Is an alkali metal ion) or formula (Ib): CH₂= CHOR¹OC (= O) R²C (= O) O ・ HY  (Ib) (In the formula, R¹And R²Is the same as above, Y Is a nitrogen atom
Or a compound containing a phosphorus atom and having a pKa of 6 to 1
2 represents the monovalent ion of a monofunctional basic compound that is 2.
And a vinyl ether represented by the formula (II): CH₂= CHOR¹OC (= O) R²C (= O) OH (II) (In the formula, R¹And R²Is the same as above)
Consisting of ether and represented by formula (Ia) or formula (Ib)
Vinyl ether represented by the formula (II)
Vinyl ether mono containing 1 mol% or more of ter
Mer composition, or formula (III):(Where Y¹, Y²And Y³The same or different
Hydrogen atom or an alkyl group having 1 to 6 carbon atoms, a is 0 or
An integer from 1 to 6, R²Is the same as above)
And (C) a fluoroolefin are copolymerized with a ketone solvent having 3 to 20 carbon atoms.
Formula (IV):(Where Y^FourIs an alkyl group having 1 to 8 carbon atoms, Y^FiveIs hydrogen
Atom or methyl group, l is 0 or an integer of 1 to 20
Alcohol mixed with alcohol solvent
The molar ratio of solvent / hydroxy group-containing vinyl monomer is 1 /
Characterized by using a solvent of 10 to 10/1 as a polymerization solvent
And a method for producing a fluorine-containing copolymer. 2. The method according to claim 1, wherein the ketone solvent is acetone or methyl ethyl ketone. 3. The method according to claim 1, wherein the alcohol solvent is methanol, ethanol, isopropanol or n-butanol. 4. A vinyl ether represented by the formula (Ia) or (1b) is a vinyl ether represented by the formula (II).
The manufacturing method according to claim 1, wherein the content is at least mol%. 5. The method according to claim 1, wherein the fluoroolefin is selected from the group consisting of tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, trifluoroethylene, vinylidene fluoride and vinyl fluoride.