JPH10231329A - Fluorine based copolymer having ring in main chain - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject copolymer capable of providing a coating membrane excellent in chemical resistance, soil-removal properties, resistance to striped soil by rain, etc., and further providing excellent preservation stability and readily drying properties to the coated material when being used as a powdered coating material. SOLUTION: This fluorine based copolymer comprises (A) a polymer unit based on a fluoroolefin, (B) a polymer unit based on a cyclic monomer having an unsaturated group copolymerizable with the fluoroolefin in a ring, (C) a polymer unit based on ethylenically unsaturated compound having neither an ester bond nor an ether bond having hardenable portions and optionally (D) a polymer unit based on one or more kinds of olefins selected from ethylene, propylene and isobutylene. The proportions of each components A to D based on the total of the components A to D is regulated so as to be 35-65mol% component A, 5-45mol% component B, 1-30mol% component C and 0-40mol% component D. Further, the fluorine-based copolymer has 2,000-100,000 number- average molecular weight, and has rings in the main chain based on the above cyclic monomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention provides a coating film having excellent chemical resistance, stain resistance, rain streak resistance, weather resistance, and the like. The present invention relates to a fluorine-based copolymer having a ring in a main chain, which gives easy drying, and a resin composition for coating containing the copolymer.

[0002]

2. Description of the Related Art Thermoplastic dispersion-type fluororesin coatings containing polyvinylidene fluoride as a main component and solvent-soluble thermosetting fluororesin coatings containing a copolymer of fluoroolefin and vinyl ether or vinyl ester as a main component. Has recently been widely used in the field of coatings such as heavy duty anticorrosion, construction, and industrial use because of the corrosion resistance and durability of the coating film, and the ease with which stains can be removed.
667, JP-A-59-102962, JP-A-61-57
609).

Further, low-pollution-type powdered fluororesin paints with reduced organic solvent emissions have been proposed to solve the problem of environmental pollution which is becoming more serious year after year (Japanese Patent Application Laid-Open Nos. 1-103670 and 2-603968; Kaihei 6-345822, JP-A-7
145332).

[0004]

The fluororesin paint mainly composed of polyvinylidene fluoride is required to be baked at a high temperature because it is thermoplastic, and the gloss of the coating film is not high because it is a crystalline resin. There is a problem that only a sufficient product is obtained and the application is limited. A low-melting fluororesin paint obtained by copolymerizing vinylidene fluoride with tetrafluoroethylene or hexafluoropropylene has also been proposed (Japanese Unexamined Patent Publication (Kokai) No. 3-220272). No solvent resistance and poor mechanical strength.

On the other hand, since the thermosetting fluororesin paint has a cured portion, powder coating can be performed at a relatively low temperature, and a coating film excellent in gloss, transparency, solvent resistance, and mechanical strength can be obtained. However, because conventional powder fluororesin paint to improve the storage stability, the glass transition temperature of the fluorine resin (hereinafter, referred to as T _g) copolymerizing becomes higher such vinyl ether monomers and vinyl ester monomers are Alternatively, a vinyl ether monomer having a hydroxyl group, an epoxy group or a carboxyl group, an allyl ether monomer, or an alkyl crotonate monomer is copolymerized as a monomer having a curing site.

As a result, a monomer having a high boiling point is used. Since this fluororesin is not so thermally stable, it cannot be dried at a high temperature, and unreacted high-boiling monomers and others remain during drying, so that it is difficult to increase the solid content of the powder. There was a problem that a gel was generated.

For the purpose of increasing the T _g , a fluorine-containing copolymer for coatings in which 2,5-norbornadiene, vinyl carboxylate and a vinyl monomer having a hydroxyl group are copolymerized has also been proposed (JP-A-6-122730). ). However, all of the vinyl monomers having a hydroxyl group are described as "hydroxyl-ester bond" or "hydroxyl group" in the molecule like hydroxyethyl crotonate, hydroxybutyl vinyl ether, hydroxyethyl allyl ether and hydroxyethyl methacrylate. And an ester bond, that is, a monomer having a curable site, which has an ester bond or an ether bond.

The fluorinated copolymer obtained by copolymerizing this monomer is susceptible to oxidation. In the case of a powder coating containing this fluorinated copolymer, gelation, an increase in molecular weight and coloring occur when heated. Therefore, drying is not easy.

In recent years, a coating composition containing a polymer having a polyfluorinated carbon chain and a hydrophilic group has been proposed in order to solve the dirt on the surface of a coated article (Japanese Patent Application Laid-Open No. HEI 1-1990).
-198653). However, although the proposed coating composition is effective in preventing spot-like stains from being generated by rainwater, it is generated in outdoor articles, for example, in areas where rainwater gathers and flows, such as under window frames of buildings. It is not enough to prevent streak-like stains (hereinafter referred to as rain streak stains).

[0010] Further, a coating composition containing a condensate of an organosilicate has been proposed (WO 94/0).
6870). However, although the composition of this proposal has an effect of reducing rain streak when observed over a long period of time, it has a problem that rain streak easily occurs in the early stage of outdoor exposure. In addition, when a coating film of this composition is repainted (recoated) with the same type of coating material on the coating film, adhesion between layers is low and peeling may occur.

[0011]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises (a) a polymerized unit based on a fluoroolefin, and (b) an unsaturated group capable of copolymerizing with the fluoroolefin. A polymerized unit based on a cyclic monomer having a ring, (c) a polymerized unit based on an ethylenically unsaturated compound having a curable site but having neither an ester bond nor an ether bond, and optionally (d) ethylene,
(A) comprising polymerized units based on one or more olefins selected from propylene and isobutylene or polymerized units based on vinyl ether having an aliphatic ring,
The proportions of (b), (c) and (d) with respect to the total are (a) 35 to 65 mol%, (b) 5 to 45 mol%, (c) 1 to 30 mol%, and (d) 0 to 0 40 mol%
Having a number average molecular weight of 2,000 to 1 in terms of polystyrene by gel permeation chromatography.
A fluorinated copolymer in the range of 00,000,
Provided is a fluorine-based copolymer having a ring based on the cyclic monomer in the main chain of the copolymer.

Further, the present invention provides a resin composition for paint containing the fluorine-based copolymer and a curing agent, and a resin composition for powder paint containing the fluorine-based copolymer and a curing agent.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The fluoroolefin giving the polymerized unit (a) means a polymerizable olefin having one or more fluorine atoms. Specifically, tetrafluoroethylene, chlorotrifluoroethylene, trifluoroethylene, vinylidene fluoride, pentafluoropropylene, hexafluoropropylene and the like are preferable, and particularly, tetrafluoroethylene, chlorotrifluoroethylene,
C2-C3 perhaloolefins, such as hexafluoropropylene, are preferred.

When storage stability and low colorability are important, a fluoroolefin containing no chlorine atom is desirable. Among them, tetrafluoroethylene is preferred from the viewpoint of low coloring property.

The polymerized unit (b) is a polymerized unit based on a cyclic monomer having an unsaturated group in the ring copolymerizable with a fluoroolefin, and the main chain of the copolymer of the present invention has this ring. is there. Having a ring in the main chain of the copolymer means that two or more of the carbon atoms constituting the ring are carbon atoms in the carbon chain constituting the main chain of the copolymer.

The monomer giving the polymerized unit (b) includes
The monomer is not limited as long as it has a cyclic unsaturated group copolymerizable with the fluoroolefin, and a compound in which this ring is an aliphatic ring or a heterocyclic ring is preferable. The monomer preferably has no ester bond.

The compound in which the above-mentioned ring is an aliphatic ring includes:
Examples thereof include compounds having two or more aliphatic rings such as norbornadienes, norbornenes, and dicyclopentadiene, and compounds having one aliphatic ring such as cyclohexene, cyclopentene, and cyclopentadiene.

Examples of norbornadienes include 2,5-norbornadiene having an aryl group such as 2-acetoxy-3-phenyl-2,5-norbornadiene and 2,5-norbornadiene.

Examples of the norbornenes include 2-norbornene and 5-ethylidenebicyclo [2.2.1] hept-2-ene having an alkyl group such as 5-ethylbicyclo [2.2.1] hept-2-ene. 2-norbornene, 5-vinylbicyclo [2.
2.1] Hept-2-ene, 5-allylbicyclo [2.
2.1] 2-norbornene having an alkenyl group such as hept-2-ene and 2-norbornene and 2-norbornene having an aryl group such as 3-phenyl-2-norbornene.

When the monomer giving the polymerized unit (b) has an alkenyl group, the alkenyl group has lower polymerizability than the unsaturated group in the ring. It can be converted into a group or the like, or can be used as it is as a vulcanization site.

Examples of the compound having a heterocyclic ring include dihydrofuran, furan, γ-pyran, pyrrole, thiophene and the like.

From the viewpoint of polymerizability and providing a high T _g , 5-ethylidenebicyclo [2.2.1] hept-2
-Ene, 5-vinylbicyclo [2.2.1] hept-2
-Ene, 2,5-norbornadiene and 2-norbornene are preferred. More preferred are 2,5-norbornadiene and 2-norbornene.

The polymerized unit (c) is a polymerized unit based on an ethylenically unsaturated compound having a curable site but having neither an ester bond nor an ether bond. The polymerized unit (c) is a monomer having no ring, or, if having a ring, is based on a monomer having no unsaturated group copolymerizable with a fluoroolefin in the ring, and the polymerized unit It is different from (b).

Examples of the hardening site include a hydroxyl group, an epoxy group, a carboxyl group, a carboxylic acid anhydride group, a hydrolyzable silyl group, an amino group, a carbonyl group, a thiol group, and an aldehyde group. When the fluorine-based copolymer of the present invention is applied to a powder coating, a hydroxyl group, an epoxy group or a carboxyl group is particularly preferred as the curable site.

It is essential that the polymer unit (c) has neither an ester bond nor an ether bond, and those having no fluorine atom are preferred. In consideration of a high polymerization yield, storage stability, availability, reactivity with a curing agent, and a boiling point, as a monomer having a hydroxyl group, an α-olefin having a hydroxyl group is preferable, and a monomer having an epoxy group is preferable. As the monomer, an epoxy compound having a vinyl group is preferable, and as the monomer having a carboxyl group, an unsaturated carboxylic acid is preferable.

As the α-olefin having a hydroxyl group, allyl alcohol is preferred. Examples of the epoxy compound having a vinyl group include an alicyclic epoxy compound having a vinyl group such as 3-vinylcyclohexene oxide;
Examples thereof include linear or branched epoxy compounds such as 1,3-butadiene monoepoxide.

The unsaturated carboxylic acids include 3-
Butenoic acid, 4-pentenoic acid, 3-hexenoic acid, 4-hexenoic acid, 5-hexenoic acid, 5-heptenoic acid, 6-heptenoic acid, 6-octenoic acid, 7-octenoic acid, 7-nonenoic acid, 8- Nonenic acid, 8-decenoic acid, 9-decenoic acid, 9-
Examples include undecenoic acid, 10-undecenoic acid, 11-tridecenoic acid, 12-tridecenoic acid, and the like. After copolymerizing a monomer having a carboxyl group blocked by vinyl ether, the carboxyl group may be dissociated under acidic conditions.

The monomer giving the polymerized unit (d) is an optional component, and may not contain this unit at all. However, by using the monomer giving the polymerized unit (d), the fluorine-containing copolymer of the present invention can be used. The flexibility of the polymer is improved, and surprisingly, the more the polymerized unit (d) is contained, the less the coloring at the time of heating at a high temperature.

The monomer giving the polymerized unit (d) is one or more olefins selected from ethylene, propylene and isobutylene, or a vinyl ether having an aliphatic ring such as cyclohexyl vinyl ether. Vinyl carboxylate and linear alkyl vinyl ether are unsuitable for the present invention because of their high coloration, but surprisingly, vinyl ethers having an aliphatic ring such as cyclohexyl vinyl ether have the characteristic of being specifically colored less. These olefins and vinyl ethers may be used in combination. A vinyl ether having an aliphatic ring is preferable as the monomer giving the polymerized unit (d) because of a large effect of reducing coloring. Unlike the polymerized unit (b), the vinyl ether having an aliphatic ring does not have an unsaturated group capable of copolymerizing with a fluoroolefin in the aliphatic ring.

The polymerized units (a), (b),
(C) and (d) relative to the total of (a) 35 to 65 mol%, (b) 5 to 45 mol%,
(C) 1 to 30 mol% and (d) 0 to 40 mol%. Preferred respective proportions are (a) 40 to 60 mol%, (b) 10 to 40 mol%, (c) 5 to 30 mol%, and (d) 0 to 20 mol%. Here, the ratio of the polymerized unit (d) of 0 mol% means that the polymerized unit (d) does not need to be contained at all.

When the fluorine-based copolymer of the present invention is used in a coating, if the proportion of the polymerized unit (a) is too small, the weather resistance is poor, and if it is too large, the compatibility with the curing agent for the coating and the compatibility with the object to be coated. Poor adhesion. When the proportion of the polymerized units (b) is too small can not raise the T _g of the fluorine based copolymer, weather resistance too much, the resulting coating film is impaired. Is not sufficient crosslinking of the resulting coating film and the ratio is too small polymerized units (c), when too much can not be higher T _g of the fluorine-based copolymer. When the proportion of the polymerized units (d) is too large it can not be increased a T _g of fluorocopolymer.

The fluorocopolymer of the present invention, T _g 30
Those in the range of -100 ° C are preferred. When used in powder coating, it is preferred that the T _g is in the range of 40 to 80 ° C.. If the _Tg is too low, blocking of the powder particles occurs, and if the _Tg is too high, sufficient fluidity cannot be obtained at the time of heating and the appearance of the coating film is impaired, which is not preferable.

The “number average molecular weight of the fluorocopolymer of the present invention in terms of polystyrene as determined by gel permeation chromatography” (hereinafter simply referred to as M _n ) is 2,
000 to 100,000, preferably 2,500
~ 100,000, more preferably 3,000 ~
30,000.

M _n in the case of using [0034] The fluorocopolymer of the present invention in paints, preferably 2,000 to 50,000,
It is more preferably from 3,000 to 20,000, and still more preferably from 3,000 to 10,000. If _Mn is too small, sufficient weather resistance cannot be obtained, and if it is too large, the viscosity of the varnish is large and coating workability is inferior. Especially when used for powder coating, the melt viscosity is too large and a smooth coating film is obtained. Is not preferred because it cannot be obtained.

When the fluorine-based copolymer of the present invention is used for a coating material, a curing agent, a curing auxiliary catalyst, a surface conditioner, a surface smoothing agent, a silane coupling agent, an ultraviolet absorber, a light stabilizer, a coloring agent, if necessary. Pigments, metallic pigments, extender pigments, and the like can be blended in the coating resin composition of the present invention. In addition, a known acrylic resin, polyester resin, alkyd resin used for a general coating composition together with a fluorine-based copolymer,
Resins such as amino resin, epoxy resin and polyurethane resin may be used in combination.

As the curing agent, methylolated melamine,
Examples include methylolated benzoguanamine, amino resin, blocked isocyanate, organic amine, organometallic compound, metal chelate compound, acid, base, blocked acid, blocked base and the like.

The mixing ratio of the curing agent to the resin composition for coating of the present invention is preferably about 5 to 70 parts by weight, more preferably 1 to 50 parts by weight, based on 100 parts by weight of the fluorocopolymer. preferable.

When the curable site of the fluorine-based copolymer is an epoxy group, a dibasic acid, a dibasic acid having a blocked carboxyl group, a polycarboxylic anhydride, dicyandiamide, a blocked isocyanate compound, or the like is used as a curing agent. Used. Regardless of which curing agent is used, the fluorine-based copolymer may have a hydroxyl group other than an epoxy group as a curable site. Particularly, in the case where the curing agent is an acid anhydride, it is preferable that a hydroxyl group coexists to improve curing reactivity.

As the dibasic acid, fumaric acid, succinic acid,
There are aliphatic dibasic acids such as adipic acid, azelaic acid, sebacic acid and dodecane diacid, isophthalic acid and aromatic dibasic acids such as trimellitic acid, with aliphatic dibasic acids being preferred, and dodecane diacid being more preferred. .

Examples of the dibasic acid having a blocked carboxyl group include adipic dihydrazide, sebacic dihydrazide, dodecane diacid dihydrazide, eicosane diacid dihydrazide, isophthalic dihydrazide, azelaic dihydrazide, suberic dihydrazide, and pyromellitic tetrahydrazide. And hydrazide compounds.

Compounds in which the above dibasic acid is blocked with vinyl ether can also be used, and in this case, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, sec-butyl vinyl ether, tert-butyl vinyl ether -Alkyl vinyl ethers such as butyl vinyl ether.

When the above-mentioned curing agent is used, a curing auxiliary catalyst may be used in combination to accelerate the curing reaction. Examples of such a curing assisting catalyst include imidazole and derivatives thereof, and amine compounds such as diaminodiphenylmethane and 1,8-diazabicyclo [5.4.0] undec-7-ene. Further, in order to improve the storage stability at room temperature, an organic acid such as formic acid or acetic acid may be used in combination.

Examples of the polycarboxylic anhydride include succinic anhydride, phthalic anhydride, hexahydrophthalic anhydride,
4-methylhexahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, polyanhydride (trade name ADD
ITOL VXL1381: manufactured by Vianova).

When the fluorine-based copolymer has an epoxy group, it can be cured by using a cationic polymerization catalyst. The catalyst is activated by heating to generate a cationic species or Lewis acid, thereby effecting ring-opening polymerization of the epoxy group. Examples of such a catalyst include aromatic sulfonium salts. Further, a copper complex of imidazole as described in Polymer Bull., 33, 347-353, 1994 can also be used.

When the curable site of the fluorocopolymer is only a hydroxyl group, a blocked isocyanate compound,
It is preferable to use a uretdione compound, tetramethoxyglycoluril (trade name, POWDERLINK 1174: manufactured by American Cyanamid Co.) as a curing agent.

Examples of the blocked isocyanate compound include polyisocyanate compounds such as hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, and xylylene diisocyanate in which isocyanate groups are blocked with a blocking agent such as ε-caprolactam, phenol, and methyl ethyl oxime ketone.
Alternatively, polyisocyanate compounds such as dimers and trimers of these polyisocyanate compounds can be used. Further, a curing auxiliary catalyst such as dibutyltin dilaurate may be used in combination.

When the fluorine-containing copolymer has a carboxyl group as a curing site, a compound having an epoxy group;
A compound having an acid amide group is used as a curing agent, and specific examples include triglycidyl isocyanurate and polyepoxide.

When the fluorine-based copolymer of the present invention is used in a resin composition for coatings, the incorporation of a polymer having a hydrophilic group can impart hydrophilicity to the coating film, thereby improving the resistance to rain streaks. Here, as the polymer having a hydrophilic group, a partially hydrolyzed product of polyvinyl acetate, a partially hydrolyzed product of ethylene-vinyl acetate copolymer, or an acrylate or methacrylic acid having an ethylene oxide addition polymer in a side chain Acid ester polymers are preferred.

_Mn of the polymer having a hydrophilic group is preferably from 500 to 5,000, and more preferably from 500 to 5,000, because it is difficult to fall off from the surface of the coating film and the fluidity during coating is good.
2,000 is more preferred.

The partial hydrolyzate has a partial hydrolysis rate of 70 to 90% because it has sufficient hydrophilicity and the powder is hard to absorb when it is used in a powder coating because the moisture absorption is not so high. Hydrolysates are preferred.

The degree of polymerization of ethylene oxide in an acrylate or methacrylate ester polymer having an ethylene oxide addition polymer in the side chain is 5 to 5.
20 is preferred. The polymer may be a copolymer of an acrylic ester or a methacrylic ester having a fluoroalkyl group.

When a polymer having a hydrophilic group is blended into the resin composition for coating of the present invention, the blending ratio is preferably about 1 to 20 parts by weight, preferably 1 to 10 parts by weight, per 100 parts by weight of the fluorine-based copolymer. Parts by weight are more preferred. With such a blending ratio, appropriate hydrophilicity is obtained, rain streaking is less likely to occur, and when used in powder coating, the powder does not have too large a hygroscopic property, so that the powder Less blocking.

When the curable site of the fluorine-based copolymer is an epoxy group, the epoxy equivalent is 250 to 3,000 mg.
Those in the range of KOH / g are preferred, especially
Those in the range of 1,500 mgKOH / g are preferred. If the epoxy equivalent is too small, the coating becomes too hard and brittle, and if it is too large, the mechanical strength of the coating deteriorates, which is not preferable.

The hydroxyl value is preferably in the range of 10 to 150 mgKOH / g when the curable site of the fluorocopolymer is a hydroxyl group, and the hydroxyl value is preferably in the range of 10 to 150 mgKOH / g when the curable site of the fluorocopolymer is a carboxyl group. Acid value is 10-200mg
It is preferably in the range of KOH / g. When the hydroxyl value or the acid value is too small, the mechanical strength of the coating film is poor, and when the hydroxyl value or the acid value is too large, the coating film becomes too hard and brittle, which is not preferable.

When the fluorine-containing copolymer has an epoxy group and a hydroxyl group, the hydroxyl value is 10 to 100 mgKOH /
g and an epoxy equivalent of 600 to 3,000 mg KO
Those in the range of H / g are preferred.

When the fluorine-based copolymer of the present invention is used in a powder coating, the fluorine-based copolymer having the above-mentioned cured site, a polymer having a hydrophilic group, a curing agent, a catalyst and various additives are usually used as powders. Become In the case of powdering, in order to be solid at room temperature and not to cause a blocking phenomenon, the residual amount of volatile components (solvents, etc.) in the fluorocopolymer when the fluorocopolymer is heated at 170 ° C. for 1 hour. (Remaining amount of heating)
Is preferably 3% or less, more preferably 2% or less, particularly preferably 1% or less.

If the remaining amount of heating exceeds 3%, the storage stability is poor, and disadvantages such as blistering of the coating film and pinholes during heating coating are not preferred. For this purpose, it is preferable that the monomer giving the polymerized units (b), (c) and (d) has a lower boiling point. The preferred boiling point is 180 ° C. or less at normal pressure.

The method for pulverizing the powder coating composition of the present invention includes a fluorine-based copolymer, a polymer having a hydrophilic group,
Dry mixing of the mixture of curing agent, catalyst and various additives,
Hot melt kneading at 100-120 ° C. followed by pulverization, classification and pulverization, dissolving a solution of the mixture in a supercritical phase using carbon dioxide and a polar organic solvent, and pulverizing by rapid expansion and so on.

The surface of the particles can be coated with organic and / or inorganic fine particles for the purpose of preventing blocking of the powder particles and improving the fluidity. Examples of such inorganic fine particles include barium sulfate, calcium carbonate, aluminum oxide, calcium silicate, magnesium silicate, antimony oxide, titanium dioxide, iron oxide, and finely divided silica. Examples of the organic fine particles include polyolefin and acrylic copolymer.

[0060]

Examples (Examples 1 to 7, Example 13, and Examples 19 to 2)
5), Comparative Examples (Examples 8 to 12, Examples 14 to 17, and Examples 26 to 3)
The present invention will be described in detail with reference to Synthesis Examples (Example 18) and (0) and a hydrophilic copolymer. In the following, some compounds are described by abbreviations shown in Tables 1 and 2.

[0061]

[Table 1]

[0062]

[Table 2]

"Example 1" 40.3 g of NBD, 27.5 g of CHVE, 12.7 AA in an autoclave (withstand pressure of 50 kg / cm ² G) with a stainless steel stirrer having an internal volume of 2.5 L
g, and cooling air degassing and pressurization with nitrogen gas were repeated to remove dissolved air. Next, 177 of HCFC225
7 g and 131.3 g of TFE were introduced into an autoclave and the temperature was raised.

When the temperature in the autoclave reached 60 ° C., the pressure showed 10.0 kg / cm ² G. afterwards,
Add 2 cc of 50% HCFC225 solution of PBPV,
The reaction was started. While maintaining the pressure with the decrease in pressure, 218.8 g of TFE, 70.0 g of CHVE, N
The reaction was continued by continuously adding 100.8 g of BD and 31.7 g of AA.

During the reaction, 50% HC of PBPV was
23 cc of FC225 solution was added continuously. After 10 hours, the supply of each monomer was stopped, the reaction was continued until ² kg / cm ² G, and then the autoclave was cooled with water to stop the reaction.

After reaching room temperature, unreacted monomers were purged and the autoclave was opened. The obtained polymer was 4
After removing the solvent for 5 hours under reduced pressure of mmHg, the mixture was pulverized with an impact hammer mill to obtain a powder of a fluorine-based copolymer. The results of composition analysis by ¹³ C-NMR are shown in the upper part of Table 3 (to the right of “/”). Further, the charged monomer composition is shown in the upper part of Table 3 (left of “/”).

"Examples 2 to 17" Tables 3 to 5
According to the charged monomer composition shown at the top (left of “/”),
Copolymerization was performed to obtain a powder of a fluorine-based copolymer. ¹³ CN
The results of composition analysis by MR are also shown in the upper part of Tables 3 to 5 (right of “/”). In addition, a of the monomer column of Tables 3-5
To d show the types of monomers corresponding to the polymerized units (a) to (d), respectively.

[0068] M _n of "physical property measurement test" Example 1-17 obtained in the fluorocopolymer, T _g, thermal stability (at 120 ° C. 5
The rate of increase in molecular weight after time heating: ◎ indicates an increase rate of less than 1.1, Δ indicates a value of less than 1.2, Δ indicates a value of less than 1.4, and X indicates a value of 1.4 or more.

"Example 18" 23.2 g of methyl methacrylate and NK ester M-40G (trade name: polyethylene glycol monomethacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd., degree of polymerization of ethylene oxide: 7) in a 1 L three-neck separable flask. 7 g, styrene 26.2 g, butyl acetate 300
g and the head space is replaced with nitrogen gas. 80 temperature
After the temperature was raised to 0 ° C., 0.8 g of azobisisobutyronitrile was added to start the reaction, and then 70 g of methyl methacrylate and 26 g of NK ester M-40G were added according to the progress of the polymerization.
The reaction was allowed to proceed by adding 2 g and 78.5 g of styrene.

After 6 hours, the reaction was completed. After cooling, the resulting polymer was removed under reduced pressure of 4 mmHg for 5 hours and then pulverized with an impact hammer mill to obtain an acrylic copolymer having a hydrophilic group. Of a hydrophilic copolymer ( _Mn about 2,000) consisting of

Example 19 37 parts of the powder of the fluorine-based copolymer obtained in Example 1 and Mersen H-696 as a hydrophilic copolymer.
0 (trade name: partial hydrolyzate of ethylene / vinyl acetate copolymer manufactured by Tosoh Corporation, _Mn: about 1,000, hydrolysis rate: 80
%) 3.7 parts, Adduct B-1530 (trade name: ε-caprolactam blocked isocyanate manufactured by Huls Co.)
9.2 parts, DBTDL 0.12 parts, Modaflow 2000
(Product name: Leveling agent of acrylic polymer manufactured by Monsanto) 0.5 part, Tinuvin 900 (Product name: benzotriazole-based ultraviolet absorber manufactured by Ciba Geigy) 2 parts, Tinuvin 144 (Product name: Hindered amine system manufactured by Ciba Geigy) 0.7 parts of a light stabilizer) was mixed for about 1 minute by a Henschel mixer (trade name: Drive render manufactured by Mitsui Kakoki Co., Ltd.), and then extruded and kneaded at a temperature condition of 90 to 130 ° C. Psconi Kneader PR-46 (manufactured by Pus Corporation) ) And melt-mixed. Next, the mixture was cooled to 10 ° C., pulverized with an impact hammer mill, and sieved with a 180-mesh wire net to obtain a thermosetting fluorine-containing powder coating.

Next, a zinc phosphate treated 1.8 m thick
The powder coating was electrostatically spray-coated on an iron plate with a thickness of 40 μm and dried and cured at 170 ° C. for 30 minutes. Table 9 shows the results.

Examples 20 to 30 Examples 2 to 9 and 15 to
A resin composition having a weight ratio shown in Tables 6 and 7 was prepared from the fluorine-based copolymer powder obtained in Example 17 in the same manner as in Example 19, and electrostatically coated in the same manner as in Example 19 to perform a coating film performance test in Table 8. Was done. The results are shown in Tables 9 to 10.

In Tables 6 and 7, Mersen H-68 was used.
22X (trade name) is a partial hydrolyzate of an ethylene / vinyl acetate copolymer manufactured by Tosoh Corporation ( _Mn about 800, hydrolysis rate 8
0%) and vinyl alcohol # 500 (trade name) is a partial hydrolyzate of polyvinyl acetate ( _Mn about 50
0, hydrolysis rate 78%) with vinyl alcohol # 200
0 (trade name) is a partial hydrolyzate of polyvinyl acetate manufactured by Kanto Chemical Co. ( _Mn: about 2000, hydrolysis rate: 78%); Coronate 2507 is ε-caprolactam blocked isocyanate manufactured by Nippon Polyurethane; Sun Aid SI-10
0 L represents a cationic polymerization catalyst manufactured by Sanshin Chemical Co., Ltd.

[0075]

[Table 3]

[0076]

[Table 4]

[0077]

[Table 5]

[0078]

[Table 6]

[0079]

[Table 7]

[0080]

[Table 8]

[0081]

[Table 9]

[0082]

[Table 10]

[0083]

The fluorocopolymer of the present invention has chemical resistance,
Gives a coating film with excellent stain removal properties and weather resistance, and gives excellent storage stability and drying properties of powder coatings and the like. By using this fluorine-based copolymer and a polymer having a hydrophilic group in combination, a coating film excellent in rain streak stain resistance can be obtained.

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification symbol FI // (C08F 214/18 232: 08 216: 08)

Claims (6)

[Claims] (1) a polymerization unit based on a fluoroolefin, (b) a polymerization unit based on a cyclic monomer having an unsaturated group in a ring copolymerizable with the fluoroolefin, and (c) a curing unit having a curable site. Polymerized units based on an ethylenically unsaturated compound having neither an ester bond nor an ether bond, and optionally (d) a polymerized unit based on one or more olefins selected from ethylene, propylene and isobutylene, or a vinyl ether having an aliphatic ring And the respective ratios to the total of (a), (b), (c) and (d) are (a) 35 to 6
5 mol%, (b) 5 to 45 mol%, (c) 1 to 30 mol%, and (d) 0 to 40 mol%, and the number average molecular weight in terms of polystyrene by gel permeation chromatography is 2,000. A fluorine-based copolymer having a ring based on the cyclic monomer in the main chain of the copolymer. 2. The fluorine-based copolymer according to claim 1, wherein the ring of the cyclic monomer is an aliphatic ring or a heterocyclic ring. 3. The fluorine-based copolymer according to claim 1, wherein the cyclic monomer is a norbornadiene or a norbornene. 4. The fluorine-based copolymer according to claim 1, wherein the curable site of (c) is an epoxy group, a hydroxyl group or a carboxyl group. 5. A coating resin composition comprising the fluorine-based copolymer according to claim 1, 2, 3 or 4, and a curing agent. 6. A resin composition for powder coatings comprising the fluorinated copolymer according to claim 1, and a curing agent.