JPH06263824A - Fluoropolymer composition - Google Patents

Abstract

PURPOSE:To obtain a fluoropolymer composition improved in material properties including pigment dispersibility by polymerizing specific monomers comprising a fluoroolefin, an alkyl vinyl ether, a hydroxylated unsaturated ether, and a (meth)acrylate to a specific mol.wt. CONSTITUTION:This polymer composition comprises 30-60mol% fluoroolefin units, 5-40mol% alkyl vinyl ether units, 3-30mol% units represented by formula I (wherein R is a 1-6C aliphatic group and (m) is O or 1), and 0.05-5mol% units represented by formula II (wherein X is H or CH3 and Y is H or a monovalent metal), and has a number-average mol.wt. (Mn) as measured by gel permeation chromatography of 1,000-100,000.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel fluoropolymer composition. More specifically, the present invention provides a fluorine-containing polymer having excellent pigment dispersibility, preventing color separation, being soluble in an organic solvent, having good compatibility with a curing agent, and having a functional group involved in crosslinking. It relates to a combined composition.

[0002]

Fluorine-containing polymers have hitherto been widely used in many fields because they are extremely excellent in heat resistance, mechanical properties, chemical resistance and weather resistance. One of its uses is in the coating field. For example, a coating material using a tetrafluoroethylene polymer or a vinylidene fluoride polymer is known, which has excellent lubricity, non-adhesiveness, weather resistance and chemical resistance. It is widely used in fields such as food, construction, and machinery.

However, since the above-mentioned fluoropolymer is insoluble in a solvent or dissolved only in a limited special solvent, it is usually used as a powder and has a drawback that the range of use is unavoidable. Therefore, in recent years, attempts have been made to develop a solvent-based coating material using a fluoropolymer having a reactive group that is soluble in an organic solvent and is curable at room temperature.
In order to solubilize the fluoropolymer in an organic solvent, it is necessary to introduce an appropriate copolymerization component, and various polymers have been disclosed as such examples (special features). Japanese Unexamined Patent Publication No. 61-275311 and Japanese Patent Laid-Open No.
57609, JP-A-62-174213,
JP-A-63-182312).

However, when these polymers are used as a coating material, the dispersibility of the pigment used for coloring becomes a problem. If the dispersibility of the pigment is poor, color unevenness may occur during the coating operation, or color separation may occur during storage, resulting in deterioration of performance as a coating material. In order to prevent such color unevenness and color separation, conventional coating materials use additives such as a pigment dispersant, a pigment dispersion aid, and a color separation inhibitor. Various physical properties such as material adhesion are likely to be deteriorated. Therefore, there is a demand for a fluoropolymer having the function of the above-mentioned additive and causing no deterioration in physical properties.

Conventionally, attempts have been made to introduce a polar group such as a carboxyl group into a polymer to impart hydrophilicity, improve adhesiveness, dyeability, pigment dispersibility, etc., and introduce a cross-linking site or an ion exchange group. There are various known methods, and they are widely used industrially, and there are many examples. Attempts have also been made to introduce carboxyl groups into fluoropolymers. However, when a polymer is synthesized using a monomer such as methacrylic acid or acrylic acid, the polymerization rate remarkably decreases and the degree of polymerization decreases, which affects yield and physical properties and becomes a problem. Therefore, a method of introducing a carboxyl group after synthesizing a fluoropolymer has been proposed (JP-A-58-1366).
No. 05), however, in this case, a two-step reaction of synthesizing the polymer and then modifying it becomes a complicated process, and the reaction temperature becomes high due to the reaction with the polymer, resulting in coloring, thickening and storage stability. There was a problem such as deterioration of properties and physical properties. On the other hand, a method of copolymerizing crotonic acid (JP-A-3-103410) and a method of copolymerizing a carboxyl group monomer (JP-A-1-289874) have been proposed, but the former is not universal. The use of a monomer has a problem in that the latter uses a limited monomer such as a fatty acid vinyl ester or a fatty acid isopropenyl ester, which is inferior in alternating copolymerization with fluoroolefins, as an essential constituent component.

[0006]

DISCLOSURE OF THE INVENTION The present invention overcomes the drawbacks of conventional fluoropolymers soluble in an organic solvent having a carboxyl group introduced for the purpose of improving the dispersibility of the pigment. The purpose of the present invention is to provide a fluoropolymer composition excellent in physical properties such as dispersibility of a pigment by a simple process using a general-purpose monomer.

[0007]

Means for Solving the Problems As a result of intensive studies to develop a fluoropolymer composition having the above-mentioned preferable properties, the present inventors have found that a fluoroolefin unit and a specific hydroxyl group-containing unsaturated ether are obtained. It was found that the object can be achieved by a fluoropolymer composition containing a unit and a specific acrylate and methacrylate unit as an essential constituent unit, and the present invention has been completed based on this finding.

That is, the present invention comprises (a) 30 to 60 mol% of a fluoroolefin unit, (b) 5 to 40 mol% of an alkyl vinyl ether unit, and (c) a general formula CH ₂ = CH-.
_{(CH 2) m -O-R} -OH (R is 1 to 6 carbon atoms in the formula
Is aliphatic, and m is a number of 0 or 1. Unit 3 to 30 mol% represented by) and (d) general formula CH ₂ = C (X) -
A unit represented by COO-Y (X in the formula is H or CH ₃ , Y is H or a monovalent metal) is 0.05 to 5 mol% (a), (b), (c). ), (D) at least, and the number average molecular weight (Mn) measured by gel permeation chromatography is 1000 to 100,
The present invention provides a fluoropolymer composition characterized by being 000.

In the fluoropolymer composition of the present invention, the fluoroolefin forming the unit (a) is an olefin having at least one fluorine atom in the molecule, and preferably, all the hydrogen atoms of the olefin are Perhaloolefins substituted with fluorine atoms and other halogen atoms are mentioned. Further, fluoroolefins having 2 or 3 carbon atoms, particularly perhaloolefins, are preferable from the viewpoint of polymerizability and properties of the obtained polymer.

Specific examples of such fluoroolefins include monofluorovinyl, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, and other fluoroethylene series, hexafluoroethylene, and other fluoropropene series, and perfluoro. −
Examples thereof include fluoroolefin compounds having 4 or more carbon atoms such as 1-butene. Of these, fluoroethylene compounds and fluoropropene compounds are preferable, and chlorotrifluoroethylene is particularly preferable. These fluoroolefins may be used alone or in combination of two or more.

In the fluoropolymer composition of the present invention, the content of the unit formed from the fluoroolefin is in the range of 30 to 60 mol%, preferably 40 to 55 mol%. If the content is less than 30 mol%, the properties of the fluoropolymer such as weather resistance will be insufficient, and if it exceeds 60 mol%, the solubility in organic solvents and the refractive index of the polymer will decrease. The gloss of the resulting coating film decreases.

In the fluoropolymer composition of the present invention,
The alkyl vinyl ether forming the unit (b) is a compound containing a vinyl group and an alkyl group in one molecule through an ether group. Specific examples of such an alkyl vinyl ether include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, t-butyl vinyl ether, pentyl vinyl ether, hexyl vinyl ether, isohexyl vinyl ether, octyl vinyl ether, 4-
Methyl-1-pentyl vinyl ether and the like can be mentioned, but among these, ethyl vinyl ether, n-butyl vinyl ether and isobutyl vinyl ether are preferable from the viewpoint of copolymerizability, economy and handling safety. These alkyl vinyl ethers may be used alone or in combination of two or more.

In the fluoropolymer composition of the present invention, the content of the unit formed from the alkyl vinyl ether is 5 to 40 mol%, preferably 10 to 35 mol%.
Is in the range. If this content is less than 5 mol%, the flexibility of the coating film obtained from this will decrease, and if it exceeds 40 mol%, the hardness of the coating film obtained from this will be poor. In the fluoropolymer composition of the present invention, the hydroxyl group-containing unsaturated ether forming the unit (c) has a general formula of CH _{2
= CH- (CH 2) m -O} -R-OH (R in the formula is an aliphatic having 1 to 6 carbon atoms, m is a number of 0 or 1.) Is a compound represented by.

Specific examples of the hydroxyl group-containing unsaturated ether include hydroxymethyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, ethylene glycol monoallyl ether and the like. Among them, those having a vinyl group Is preferable since it has good reactivity with fluoroolefins, and 4-hydroxybutyl vinyl ether is particularly preferable. These hydroxyl group-containing unsaturated ethers are
Each may be used alone, or two or more kinds may be used in combination.

In the fluoropolymer composition of the present invention, the content of the (c) unit is in the range of 3 to 30 mol%, preferably 5 to 20 mol%. If this content is less than 3 mol%, the crosslinking and curing time will be long, and the chemical resistance, solvent resistance, stain resistance, etc. of the coating film will be insufficient. As the solubility decreases,
When mixed with a curing agent, the gelation time is shortened, and the coating properties and workability of the paint are reduced.

In the fluoropolymer composition of the present invention,
Particular acrylates and methacrylates that form (d) is a unit of the general formula _{CH 2 = C (X) -COO} -Y
(X in the formula is H or CH ₃ , and Y is H or a monovalent metal). Specific examples of such specific acrylates and methacrylates include methacrylic acid, acrylic acid, sodium methacrylate, sodium acrylate, potassium methacrylate, potassium acrylate and the like. Among these, methacrylic acid and acrylic acid are more preferable from the viewpoint of versatility. These acrylates and methacrylates may be used alone or in combination of two or more.

In the fluoropolymer composition of the present invention, the content of the unit (d) is in the range of 0.05 to 5 mol%, preferably 0.1 to 3 mol%. This content is 0.
If it is less than 05 mol%, the effect of improving the dispersibility of the pigment is insufficient, and if it exceeds 5 mol%, the physical properties such as weather resistance deteriorate. The fluoropolymer composition of the present invention has the above-mentioned specific amounts of the units (a), (b), (c) and (d) as essential constituent units, which improves the dispersibility of the pigment, A fluorine-containing polymer composition containing a functional group that can be cured at room temperature can be obtained. Further, in addition to these units, other copolymers can be copolymerized in a range not exceeding 30 mol% as needed such as the purpose of use. It can also contain monomer units.

Examples of the copolymerizable monomer include cyclic vinyl ethers such as 2,3-dihydrofuran,
Olefins such as ethylene, propylene and isobutylene; haloolefins such as vinyl chloride and vinylidene chloride; vinyl acetate, carboxylic acid vinyl esters such as n-vinyl butyrate; isopropenyl carboxylic acid such as isopropenyl acetate and isopropenyl propionate. Cycloalkyl vinyl ethers such as esters, cyclopentyl vinyl ether, cyclohexyl vinyl ether,
Aryl vinyl ethers such as phenyl vinyl ether, o-, m-, p-tolyl vinyl ether, benzyl vinyl ethers, aralkyl vinyl ethers such as phenethyl vinyl ether, aromatic vinyl compounds such as styrene and vinyltoluene, vinyltrimethoxysilane, allyltriethoxy. Silane compounds having a hydrolyzable silyl group and an unsaturated bond such as silane, hydroxyethyl acrylate, hydroxyethyl methacrylate, glycidyl methacrylate, mono (2-methacryloyloxyethyl) acid phosphate, acrylates and methacrylates containing reactive groups such as sulfoethyl methacrylate , Methyl methacrylate, ethyl methacrylate,
General-purpose acrylates and methacrylates such as butyl methacrylate, methyl acrylate, ethyl acrylate, and butyl acrylate, crotonic acid and its esters, acrylamides such as acrylamide and N-methylolacrylamide, allyl glycidyl ether, ethyl allyl ether, etc. Allyl ethers, carboxylic acid allyl esters such as allyl acetate and allyl propionate,
Examples include allyl alcohol. Among these, cyclic vinyl ethers such as 2,3-dihydrofuran are preferable because they can increase the glass transition temperature of the fluoropolymer composition in a small amount and impart various properties such as improved hardness and stain resistance. These copolymerizable monomers may be used alone or in combination of two or more.

The molecular weight of the fluoropolymer composition of the present invention is a number average determined by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent and monodisperse polystyrene of known molecular weight as a standard substance. A molecular weight (Mn) of 1000 to 100,000,
It is necessary to be preferably in the range of 3000 to 80,000. If the number average molecular weight (Mn) deviates from the above range, the object of the present invention cannot be sufficiently achieved.

The fluoropolymer composition of the present invention having such a composition and molecular weight is soluble in an organic solvent and has various physical properties such as pigment dispersibility, color separation prevention property, substrate adhesion property and adhesive property. Will be excellent. The fluororesin composition of the present invention is
It can be produced by copolymerizing a monomer mixture in a predetermined ratio in the presence or absence of a solvent, using a polymerization initiator, an ionizing radiation or the like as a polymerization initiation source.

As the polymerization initiator, a water-soluble one or an oil-soluble one is appropriately used depending on the type of polymerization and the kind of solvent used as desired. As the water-soluble polymerization initiator, for example, a sulfated salt such as potassium persulfate, hydrogen peroxide, or a redox initiator composed of a combination of these with a reducing agent such as sodium hydrogen sulfite or sodium thiosulfate, and further Inorganic initiators in the presence of small amounts of iron, ferrous salts, silver nitrate, etc., dibasic acid peroxides such as disuccinic acid peroxide, diglutaric acid peroxide, monosuccinic acid peroxide, azobisisobutylamidine dibasic acid Examples include organic initiators such as salts. Further, as the oil-soluble initiator, for example, t
-Butylperoxyisobutyrate, t-butylperoxyacetate, t-butylperoxypivalate, t
-Peroxy ester type peroxides such as butyl peroxy 2-ethylhexanoate, diisopropyl peroxy dicarbonate, di n-propyl peroxy dicarbonate, bis (4-t-butylcyclohexyl) peroxy dicarbonate Examples thereof include diacyl peroxide type peroxides such as dialkyl peroxydicarbonate type peroxide, isobutyryl peroxide, lauroyl peroxide and benzoyl peroxide, and azo type polymerization initiators such as azobisisobutyronitrile.

The amount of these polymerization initiators to be used is appropriately selected depending on the kind, the conditions of the copolymerization reaction, etc., but 0.005 to 5% by weight based on the total amount of the monomers usually used,
It is preferably selected in the range of 0.05 to 2%. The polymerization method is not particularly limited, for example, bulk polymerization method,
A suspension polymerization method, an emulsion polymerization method, a solution polymerization method or the like can be used, but in view of the stability of the polymerization reaction operation, the ease of separation of the produced copolymer, the form of use as a paint, etc., an aqueous medium is used. Emulsion polymerization method, alcohols such as t-butanol, esters such as ethyl acetate and n-butyl acetate,
Solution polymerization using aromatics such as xylene and toluene, ketones such as methyl isobutyl ketone, and saturated halogenated hydrocarbons having one or more fluorine atoms as a solvent,
A bulk polymerization method which does not require separation from a solvent is preferably used.

When the copolymerization is carried out in an aqueous medium, a suspending agent or an emulsifying agent is usually used as a dispersion stabilizer, and a basic buffer is added to adjust the pH value of the reaction solution during the polymerization to 4, preferably. It is desirable to set it to 6 or more. The addition of the basic substance is also effective in the case of the solution polymerization method and the bulk polymerization method. Furthermore, there are no particular restrictions on the polymerization type,
Any of a batch type, a semi-continuous type, and a continuous type can be used.

The reaction temperature in the copolymerization reaction is usually −
Within the range of 30 to + 150 ° C, it is appropriately selected depending on the type of the polymerization initiation source and the polymerization medium. For example, when the copolymerization is carried out in an aqueous medium, it is usually 0 to 100 ° C, preferably 10 to 9 ° C.
It is selected in the range of 0 ° C. The reaction pressure is not particularly limited, but is usually selected in the range of 0.1 to 100 kg / cm ² , preferably 0.5 to 30 kg / cm ² . Further, the copolymerization reaction can be carried out by adding an appropriate chain transfer agent.

The fluoropolymer composition of the present invention basically contains a hydroxyl group as a curing reaction site, and is a curing agent used for ordinary thermosetting acrylic paints, such as melamine curing. Agent, a urea resin curing agent, a polybasic acid curing agent, and the like can be used for heat curing. Examples of the melamine curing agent include butylated melamine, methylated melamine, and epoxy-modified melamine, and those with various degrees of modification are appropriately used depending on the application, and the degree of self-condensation can also be appropriately selected. Examples of the urea resin curing agent include methylated urea resin and butylated urea resin, and examples of the polybasic acid curing agent include long-chain aliphatic dicarboxylic acids, aromatic polyvalent carboxylic acids and their acid anhydrides. And so on. Furthermore, blocked polyvalent isocyanates can also be preferably used as a curing agent. Further, when using a melamine curing agent or a urea resin curing agent, curing can be promoted by adding an acidic catalyst.

Further, the fluoropolymer composition of the present invention can be cured at room temperature using polyisocyanates. Preferred examples of the polyvalent isocyanates include non-yellowing diisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate, and adducts thereof, polyisocyanates having an isocyanurate ring, and the like. A polyvalent isocyanate having an isocyanurate ring having good compatibility with the composition is suitable. When using these polyvalent isocyanates to cure at room temperature, a known catalyst such as di-n-butyltin dilaurate may be added to accelerate the curing.

The fluorine-containing polymer composition of the present invention can be used as a fluorine-based coating composition containing this as a main component, and when the fluorine-containing polymer composition is used as a solution type coating composition, Various solvents can be used. Examples of the solvent include aromatic hydrocarbons such as toluene and xylene, alcohols such as n-butanol, esters such as n-butyl acetate, ketones such as methyl isobutyl ketone, glycol esters such as ethyl cellosolve, Furthermore, various commercially available thinners and the like can be mentioned.

For the preparation of this solvent-based paint, the fluoropolymer composition and the solvent are usually used for the preparation of paints such as a ball mill, a paint shaker, a sand mill, a jet mill, a triple roll and a kneader. It can be carried out by homogeneously mixing with a mixer. At this time, if desired, a pigment dispersion stabilizer, a viscosity modifier, a leveling agent, an antigelling agent, an ultraviolet absorber and the like can be added.

When the coating material containing the fluoropolymer composition as a main component is a heat-curable so-called baking coating material, melamine, urea resin,
It is used as a one-component paint by blending a curing agent such as polybasic acid or its anhydride, blocked polyvalent isocyanates, and peroxide. On the other hand, when using a room temperature curable paint,
Usually, unblocked polyvalent isocyanates are used as a curing agent component, and a curing agent liquid containing this curing agent component is separately prepared to obtain a two-component paint. In this case, the polyisocyanate and the type of the catalyst and the amount thereof added, the concentration of the fluororesin, the content of the hydroxyl group-containing unsaturated ether unit in the copolymer, etc. can be appropriately selected for about 1 to 10 hours. It is possible to obtain a paint which has a working time and is cured at room temperature for several hours to several days to give a coating film having good physical properties.

Further, the fluorine-based coating material containing the fluorine-containing polymer composition as a main component has a gloss after the coating step and can give a coating film excellent in weather resistance and stain resistance under mild conditions, For example, it is useful as a baking paint for exteriors of vehicles such as color aluminum plates, aluminum sashes, aluminum wheels, and automobiles, or as a normal-drying paint that can be applied on site such as building materials and buildings. Furthermore, regarding the material of the base material of the object to be coated, in addition to metallic materials, inorganic materials such as glass and concrete, FRP, polyethylene, polypropylene, ethylene-vinyl acetate copolymer,
It is preferably used for coating plastics such as nylon, acrylic resin, polyester, ethylene-polyvinyl alcohol copolymer, polyvinyl chloride, polyvinylidene chloride and polycarbonate, and organic materials such as wood. Also,
The fluorine-based coating material containing the fluorine-containing polymer composition as a main component is also useful in specific applications such as aluminum pools, exterior colored glass, and cement roof tiles.

Hereinafter, the present invention will be described in more detail with reference to examples.

[0032]

Example 1 A stainless steel autoclave with an internal volume of 3 liters equipped with a stirrer was charged with 0.78 g of potassium carbonate and 0.9 g of potassium propionate and then deaerated.
-Hydroxybutyl vinyl ether (hereinafter abbreviated as HBVE) 104.2 g, isobutyl vinyl ether (hereinafter I
BVE) 204.0 g, ethyl vinyl ether (hereinafter EVE) 72.7 g, 2,3-dihydrofuran (hereinafter DHF), 70.7 g, xylene (hereinafter XY) 461 g, t-butylper Oxypivalate (Nippon Yushi Co., Ltd. product "Perbutyl PV", net 7
Including 0%, hereinafter abbreviated as PV) 12.4 g and chlorotrifluoroethylene (hereinafter abbreviated as CTFE) 120 g
Methacrylic acid (hereinafter referred to as MA
It is abbreviated as). 7.8 g of CTFE is injected into the autoclave at a constant flow rate for 4 hours by a pump, and CTFE 468 g is 120 g
It was pressed in at a speed of / hour. While stirring the autoclave, the temperature was raised from room temperature to 56 ° C in 30 minutes, and the reaction was continued at 56 ° C with stirring, and after 6 hours, the temperature was raised to 78 ° C in 15 minutes and the reaction was continued for 2 hours, and stirring was stopped for 30 minutes. After the temperature was lowered to room temperature with, the unreacted monomer was released to stop the reaction. Release the autoclave,
The reaction solution was taken out. After concentration, reprecipitation with n-hexane and washing were performed to obtain a polymer composition. The yield of the obtained polymer composition was 1019 g. When the composition analysis of this polymer composition was carried out by elemental analysis, IR analysis, OH value measurement, acid value and residual monomer measurement, CTFE / IBVE /
EVE / DHF / HBVE / MA = 49/20/10 /
It was 10/10/1 (molar ratio). The number average molecular weight of this polymer composition was 13,500. Red organic pigment (Chromophine Red 682 manufactured by Dainichiseika Co., Ltd.)
0) is used, the pigment weight concentration is 34%, the solid content is 40%
A pigment dispersion test was conducted in the following mixing ratio. Disperser R
After dispersing for 5 hours using ed Deville RC5000A, after applying to a test plate using an applicator,
It was dried at room temperature for 30 minutes and then heated at a temperature of 100 ° C. for 1 hour. A coating film having a thickness of about 50 μm was obtained on the test plate after heating. The 60-degree specular gloss of this coating film according to JIS K5400 was 68.

[0033]

Example 2 HBVE, IBVE and MA were charged at 106.6 g and IBVE was 209.9 g and 0.9, respectively.
Polymerization was carried out in the same manner as in Example 1 except that the amount was changed to 5 g.
g of polymer composition was obtained. The composition of this polymer composition is
CTFE / IBVE / EVE / DHF / HBVE / MA
= 50 / 20.8 / 10/10 / 9.1 / 0.1 (molar ratio), and the number average molecular weight was 14,600. The 60-degree specular gloss of the coating film obtained after dispersing the pigment by the same test method as in Example 1 was 66.

[0034]

Example 3 HBVE, IBVE and MA were charged at 106.6 g, IBVE was 208.8 g and 1.9, respectively.
Polymerization was performed in the same manner as in Example 1 except that the amount was changed to 100 g
A polymer composition of was obtained. The composition of this polymer composition is C
TFE / IBVE / EVE / DHF / HBVE / MA =
It was 50 / 20.7 / 10/10 / 9.1 / 0.2 (molar ratio) and the number average molecular weight was 12,300. The 60-degree specular gloss of the coating film obtained after dispersing the pigment by the same test method as in Example 1 was 68.

[0035]

Example 4 Polymerization was carried out in the same manner as in Example 1 except that the amounts of HBVE, IBVE and MA charged were 106.6 g and IBVE 206.4 g and 4 g, respectively, to obtain 1016 g of a polymer composition. The composition of this polymer composition is CTF.
E / IBVE / EVE / DHF / HBVE / MA = 50
/20.4/10/10/9.1/0.5 (molar ratio) and the number average molecular weight was 11,600. The 60-degree specular gloss of the coating film obtained after dispersing the pigment by the same test method as in Example 1 was 66.

[0036]

[Comparative Example 1] 0.78 g of potassium carbonate and 0.9 g of potassium propionate were charged into an autoclave with a stirrer made of stainless steel and having an internal volume of 3 liters, and after degassing, H
BVE106.6g, IBVE211.0g, EVE7
2.7 g, DHF70.7 g, XY461 g, PV1
2.4 g and CTFE of 120 g were charged, and CTFE of 468 g was injected at a rate of 120 g / hour from the start of temperature increase. While stirring the autoclave, the temperature is raised from room temperature to 56 ° C in 30 minutes, and further, while stirring, 56
The reaction was continued at 6 ° C, and after 6 hours, the temperature was raised to 78 ° C in 15 minutes and the reaction was continued for 2 hours. After stirring was stopped and the temperature was lowered to room temperature in 30 minutes, unreacted monomer was released to stop the reaction. The autoclave was released and the reaction solution was taken out. After concentration, reprecipitation with n-hexane and washing were performed to obtain a polymer composition. The yield of the obtained polymer composition was 1037 g. Elemental analysis, IR analysis of the composition analysis of this polymer composition
CTFE / IBVE / EVE / DHF / HBV as determined by analysis, OH number measurement and residual monomer measurement
E = 50/21/10/10/9 (molar ratio).
The number average molecular weight of this polymer composition was 15,100. The 60-degree specular gloss of the coating film obtained after dispersing the pigment by the same test method as in Example 1 was 16.

[0037]

As described above, the fluoropolymer composition of the present invention can form a coating film having good pigment dispersibility and excellent gloss.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C08F 220: 02)

Claims (1)

[Claims] 1. (a) Fluoroolefin unit 30 to 60
Mol%, (b) an alkyl vinyl ether units 5 to 40 mol%, (c) general formula _{CH 2 = CH- (CH 2)} m -O-
R-OH (R in the formula aliphatic having 1 to 6 carbon atoms, m is a number of 0 or 1.) Unit 3 to 30 mol% represented by and (d) general formula CH ₂ = C ( X) -COO-Y (wherein X is H or CH ₃ , and Y is H or a monovalent metal) is 0.05 to 5 mol% of a unit (a),
A fluoropolymer composition containing at least (b), (c) and (d) and having a number average molecular weight (Mn) of 1000 to 100,000 as measured by gel permeation chromatography. .