JPH01158015A - Fluorine-containing copolymer - Google Patents

Abstract

PURPOSE:To obtain the title copolymer, having a specific structure and capable of sufficiently dissolving or dispersing in an aqueous medium without using a surfactant and providing films having excellent hardness, adhesive properties to substrates, glossiness, resistance to fouling, boiling water and weather. CONSTITUTION:The aimed copolymer containing 20-80mol% units expressed by the formula-CFX-CF2- (X is Cl or F) and 80-20mol% units expressed by formula I (R<1> is 2-6C alkylene or 4-10C bifunctional alicyclic group; M is H, alkaline metal, etc.) or further <=40mol% units expressed by formula II or III (R<5> is 1-12C alkyl, 4-10C monofunctional alicyclic group, etc.; k is 0 or 1; j is 2-6). The above-mentioned copolymer is preferably obtained by copolymerizing a monomer expressed by the formula CFX=CF2, such as tetrafluoroethylene, with a monomer expressed by formula IV, such as hydroxyethyl acrylate, and, as necessary, a monomer expressed by formula V, such as vinyl acetate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a fluorine-containing copolymer suitable as a material for water-based paints.

[Prior Art and Problems] Coating compositions in which a fluorine-containing copolymer is dispersed in an aqueous medium have been known, but conventional ones have a fluorine-containing copolymer dispersed in an aqueous medium. Furthermore, since it contains surfactants such as emulsifiers, it tends to be colored when the paint is baked, and even if it is not colored, the resulting paint film lacks gloss, transparency, hardness, etc.

As a result of intensive studies on water-based fluororesin paints with excellent properties as described above, the present inventors found that a fluorine-containing copolymer containing a monomer with a specific chemical structure is free of surfactants, etc. found that it dissolves or disperses well in water,
This has led to the present invention.

An object of the present invention is to provide a fluorine-containing copolymer that can be used as a material for a water-soluble paint that can provide a coating film with excellent gloss, transparency, hardness, and the like.

[Means for Solving the Problems] The gist of the present invention is to contain 20 to 80 mol% of structural units represented by the formula: %formula% ((wherein, X represents chlorine or fluorine), and the formula:% Formula % (wherein R' is an alkylene group having 2 to 6 carbon atoms or a divalent alicyclic group having 4 to 10 carbon atoms, M is hydrogen, an alkali metal, a NllR2R3R4 group [however, R2, R3 and R4
are the same or different and are hydrogen, an alkyl group having 1 to 6 carbon atoms, or a hydroxyalkyl group having 1 to 6 carbon atoms.

] or RH group [However, R is a nitrogen-containing cyclic compound having 4 to 9 carbon atoms. ], n represents an integer of 2 to 6. ), or 80 to 20 mol % of the structural unit represented by the above structural units 0) and Ql) of the formula: % formula % (wherein R5 is an alkyl group having 1 to 2 carbon atoms, 4 to 2 carbon atoms, (1) Structural unit or formula represented by 0 monovalent alicyclic group or fluoroalkyl group having 2 to 10 carbon atoms, k represents 0 or 1: % formula % (wherein j is 2 to 6 ) is a fluorine-containing copolymer containing 40 mol% or less of any one of the structural units represented by .

[Function and Examples] The number average molecular weight of the fluorine-containing copolymer is usually 2000.
~100,000, preferably 5,000-80,000.

The fluorine-containing copolymer can be prepared by a series of reactions (1) to (g) below.

(G) [Copolymerization] A monomer represented by the formula; % formula %) (wherein, Monomer and formula; %Formula % (In the formula, R5 and k are the same as above) are copolymerized to form a copolymer having structural units represented by formulas (1) and (h). Obtain a polymer.

In addition, since the monomer (lit'') is copolymerized as necessary, it may not be included in the copolymer.

Examples of the monomer represented by formula (1') include tetrafluoroethylene and chlorotrifluoroethylene.

Examples of the monomer represented by formula (iii) include hydroxyethyl, hydroxypropyl, hydroxybutyl,
Examples include hydroxypentyl and hydroxyhexyl.

As the monomer represented by formula (111''), R' is an alkyl group such as methyl, ethyl, propyl, isobutyl, hexyl, octyl, decyl, lauryl; an alicyclic group such as cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, bornyl, etc. Formula group, 2.2.2-)lifluorooctyl, 2,2゜3.3-tetrafluoropropyl, 2
．． 2.3.3.3-pentafluoropropyl, 2,2,
3,3,4,4,5,5-octafluoropentyl, 2
．． 2,3.3,4.4.4-hebutafluorobutyl, 2
．． 2.3, 3.4, 4.5.5, 6. B, 7.7.8.
Examples include fluoroalkyl groups such as 8.9゜9-hexadecafluorononyl, and specific examples include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl caproate, vinyl laurate, and versatic. Vinyl esters such as vinyl acid, vinyl cyclohexanecarboxylate; methyl vinyl ether, ethyl vinyl ether, 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, 2.2.2-trifluoroethyl vinyl ether, 2.2.3.3-tetrafluoropropyl vinyl ether, 2.2.3.3.8-pentafluoropropyl vinyl ether, 2.2.3.3,4.
4,5.5-octafluoropentyl vinyl ether,
Examples include vinyl ethers such as 2.2, 3.3.4, 4.4-heptafluorobutyl vinyl ether.

(7) [Esterification of hydroxyl groups contained in copolymer] The copolymer obtained in (1) above and the acid represented by the formula: %formula%) (wherein R1 is the same as above) Anhydride is reacted to form a structural unit represented by the formula: C, where R1 and n are the same as above. ) into a structural unit.

In this reaction, if it is desired to leave a portion of the structural unit (2), less than an equivalent amount of the acid anhydride may be reacted.

Examples of the acid anhydride to be reacted include maleic anhydride, succinic anhydride, methylsuccinic anhydride, adipic anhydride, glutaric anhydride, itaconic anhydride, citraconic anhydride, 1,2-cyclohexanedicarboxylic anhydride, and 4-cyclohexane dicarboxylic anhydride.
Diels-Alder reaction of methyl-1,2-cyclohexanedicarboxylic acid, cis-4-cyclohexene-1,2-cyclohexanedicarboxylic anhydride, I-cyclohexene-1,2-dicarboxylic anhydride, or cyclopentadiene and maleic anhydride. Examples include additives.

(III) [Neutralization of carboxyl group contained in structural unit (V)] Formula obtained in (1) above: A copolymer having structural units represented by (1) and (V) (in some cases, (having either structural unit (111) or , the carboxyl group contained in the structural unit (v) is neutralized to obtain the copolymer of the present invention.

In addition, if the structural unit of the copolymer is one in which M contained in O) is hydrogen, that is, if a part of the structural unit (V) is required, the neutralization reaction (2) will only be completed incompletely. When a fluorine-containing copolymer that can be stably dispersed in a medium for a long period of time is required, this neutralization reaction is carried out on half or more of the carboxyl groups, preferably all of them.

The copolymerization in (1) above is usually carried out in an aqueous medium at a temperature of -20°C.
~150°C, preferably 5~95°C, pressure θ ~30kg
/CrjG, preferably 0-10kg/CIJ
It is done in G.

Examples of water-soluble media include ketones such as acetone, methyl ethyl ketone, and cyclohexanone, alcohols such as methanol, ethanol, 1-propanol, 1-butanol, and n-butanol, and ethers such as dimethyl calpitol, cellosolve, and tetrahydrofuran. , amides such as dimethylformamide and dimethylacetamide, and acetate esters such as methylcellosolve acetate.

When carrying out the copolymerization, the amount of polymerization initiator is usually 0.01 to 5 parts by weight, preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the total monomers.
05 to 1.0 parts by weight are used. Examples of polymerization initiators include genie propyl peroxydicarbonate, t-
Examples include peroxides such as butyl peroxybutyrate and benzoyl peroxide, and azo compounds such as azobis-I-butyronitrile and azobisvaleronitrile.

When carrying out the above copolymerization, the fluorinated water cord is detached from the copolymer, the pH in the system is lowered, and the vinyl group and hydroxyl group of the monomer of the formula: (il") react, and this monomer Since the monomer may be cyclized, it is preferable to add a pII regulator such as a tertiary amine in an amount of 0.1 to 5 parts by weight per total monomer.

After the copolymerization of (I) is completed, the resulting reaction mixture is usually evacuated to remove the polymerization medium having functional groups such as alcohol.

The esterification reaction of (It) above usually involves the copolymer,
The acid anhydride and catalyst are mixed into the reaction medium and the
C. for 1 to 10 hours. Examples of the catalyst include zirconium naphthenate, tetrabutyl zirconate, tetrabutyl titanate, and tetraoctyl titanate. Examples of the reaction medium include acetone, methyl ethyl ketone, cyclohexanone, dimethyl carpitol, and methyl cellosolve acetate. The reaction molar ratio between the copolymer and the acid anhydride is usually 110.5 to 115. The catalyst is usually used in an amount of 0.01 to 1 part by weight per 100 parts by weight of the copolymer.

In addition, the structural unit (V), in addition to the acid anhydride, has the formula: % formula % (in the formula, R1 is the same as above, R6 and R7 are the same or different, a hydroxyl group, a carbon number of 1 to 5 represents an alkoxy group, a -0M group [where M is the same as above], a trimethylsilyl group, or a tetrahydropyranyl group.)
A compound represented by the formula: %Formula%) (wherein R1 is the same as above, X is a halogen, and R8 represents a halogen or an alkoxy group having 1 to 5 carbon atoms), the formula: %Formula%() ( (wherein, R1 is the same as above) or the compound represented by the formula: %Formula% (wherein, R1 and X are the same as above) is contained in the structural unit represented by formula: 0 10H
group to form an ester bond (the above formula: (R'OC- group in the middle, formula: Mt.)
(7) 1100c-group or formula: (The x0-group in the middle reacts.), then the above formula: (The R7 group contained in the compound represented by ω is a hydroxyl group and 10M
group [However, M is the same as above. ], unless -COR
It can also be obtained by hydrolyzing a -COR8 group or a -COR8 group or a 10N group.

In this esterification reaction, the same catalyst as used in a normal esterification reaction can be used as a catalyst. Examples of catalysts include acidic catalysts such as para-toluenesulfonic acid and sulfuric acid, basic catalysts such as sodium hydroxide, potassium hydroxide, and sodium methylate, and others such as zirconium naphthenate, nickel naphthenate, zinc acetylacetone, and cobalt acetylacetone. Can be mentioned. The catalyst is 0.01-10 parts by weight per 100 parts by weight of the copolymer.
Use parts by weight. The reaction temperature is 50-130°C.

The hydrolysis reaction of the -COR7 group, -COR8 group or 10N group is carried out in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the copolymer.
It can be carried out using parts by weight of catalyst and at a reaction temperature of 30 to 100°C. Examples of the catalyst include mineral acids, alkali metal hydroxides, alkaline earth metal hydroxides, and alkali metal carbonates in an amount of 0.5 to 10% by weight.

In the neutralization reaction (5), the copolymer obtained in (It) is dissolved in water or alcohol to a concentration of 10 to 70% by weight, and the alkali metal hydroxide or formula:% formula% (formula (where R2, R3 and R4 are the same as above) can be added.

Examples include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia, trimethylamine, monoethylamine, diethylamine,
Triethylamine, tripropylamine, dimethylethanolamine, jetanolamine, triethanolamine, pyridine, piperidine and the like can be mentioned.

The reaction molar ratio between the copolymer of the present invention and the alkali metal hydroxide etc. is usually 110.5 to 1/2. Examples of alcohols include methanol, ethanol, l-propanol, t-butanol, and the like.

When the copolymer of the present invention is used in a fluororesin coating, water alone or a mixture of water and alcohol is added to the reaction mixture after the reaction (IID) to increase the concentration of the copolymer from 5 to 5.
Dilute to 50% by weight. This alcohol is, for example, methanol, ethanol, I-propanol, t-butanol, etc.

When the copolymer of the present invention is used as a material for a fluororesin paint, it is possible to crosslink the copolymer by reacting with the hydroxyl group and/or carboxyl group contained in the copolymer of the present invention at 100°C or higher. It is possible to add curing agents and additives commonly used in paints. Examples of the curing agent include block isocyanates such as hexamethylene diisocyanate trimer, methylated melamine,
Examples include melamine resins such as methylolated melamine and butyrolated melamine, amino resins such as benzoguanamine, and urea resins such as methylated urea and butylated urea. The curing agent is usually reacted in an amount of 0.5 to 2 equivalents with respect to the functional group. Examples of additives include pigments, ultraviolet absorbers, leveling agents, anti-cissing agents, and anti-scald agents.

The fluororesin paint that can be obtained from the copolymer of the present invention can be used in the same manner as conventional fluororesin paints, and can be used as anticorrosion and antistatic paints for aluminum sash, roof tiles, colored steel plates, metal solders, etc. , can be applied to tanks, pipes, etc.

[Example] Preparation Example 1 (Preparation of copolymer of the present invention) (1) Hydroxybutyl vinyl ether (hereinafter referred to as IIBVE) was placed in a 1000 ml glass autoclave.

) tong, methyl cellosolve acetate eog, 180 g of t-propanol and 1 ml of N-dimethylbenzylamine, and after replacing the space with nitrogen, chlorotrifluoroethylene (hereinafter referred to as CTPE) was added.
116g was added and heated to 65°C.

The pressure when the temperature became stable was 8.2 kg/aJG.

Next, methyl cellosolve acetate/1-propatool (1 by weight) in which 2.5 g of azobisisobutyronitrile was dissolved
40 g of the mixture of 71) was added to start polymerization. The temperature was maintained for 20 hours with stirring. The pressure of the autoclave after the elapse of this time was 0.2 kg/cjG. 475 g of varnish containing 42.5% by weight of non-volatile components was obtained.

The varnish was heated to 60 to 80°C and the pressure was reduced to 100 to 300 mmHg using an evaporator to remove l-propanol to obtain a copolymer mixture.

(II) 500% of the copolymer mixture obtained in the above (I)
Pour into a 10ml glass flask and stir while stirring.
9 g of 1,2-cyclohexanedicarboxylic anhydride (esterifying agent), 50 g of acetone and 100 μg of zirconium naphthenate were added, and the mixture was reacted for 5 hours while heating to reflux the acetone.

(nr) After the reaction mixture was cooled to room temperature, 70 g of triethylamine (neutralizing agent) was added to it while stirring.
A mixture of 5 g of ethanol was added dropwise over 1 hour to obtain a mixture containing a fluorine-containing copolymer.

The results of elemental analysis, infrared absorption analysis, and measurement of intrinsic viscosity [η] of the copolymer obtained by removing the solvent, etc. in the copolymer mixture obtained above are as follows. Met.

Elemental analysis = (Analysis value) Carbon 52.6%, Nitrogen 2.3%
, chlorine 8.4%, fluorine 13.2%, (theoretical value) carbon 5
2.8%, nitrogen 2.3%, chlorine 8.2%, fluorine 13.
1%.

Infrared absorption analysis (cm-1): 3200-3400
(-011), 2900 (-C)12-), 2300
~2700 (-N114), 1100 ~ 1200 (-C
F2- or -〇〇IF-), 1700-1740 (
-Coo-), 1430 (cyclohexyl).

Intrinsic viscosity [η]: 0.055 (solvent: methanol, 35°C) From the above analysis results, the obtained copolymer of the present invention has C
It was found to consist of 50 mol% units based on TPIE, 10 mol% units based on II n V B and 40 mol% units of the formula:

Preparation Examples 2 to 12 and Reference Preparation Examples 1 to 3 Instead of the monomer, esterifying agent, or neutralizing agent used in Preparation Example 1,
A fluorine-containing copolymer was prepared in the same manner as in Preparation Example 1, except that the materials shown in the table were used.

The analysis results of the copolymers of Preparation Examples 6, 7, and 12 and Reference Preparation Example 3 were as follows.

Preparation Example 6: Elemental Analysis = (Analysis Value) Carbon 55, 89g, Nitrogen 1.
8%, chlorine 8.3%, fluorine 12.3%, (theoretical value) carbon 55.1%, nitrogen 1.85%, chlorine 7.9%, fluorine 12.7%.

Infrared absorption analysis (cm-1): 2900 (-CH
3 or -GH2-), 2300-2700 (-NH
4) , 1100-1200 (-CF2- Mataba C
(JP-), 1700-1740 (-Coo-), 1
430 (cyclohexyl). .

Intrinsic viscosity [η]: 0.048 (solvent: methanol, 35°C).

From the above analysis results, the obtained copolymer of the present invention has C
It was found to consist of 47 mol % units based on TFH, 30 mol % units based on vinyl versatate and 23 mol % units of the formula: % formula %.

Preparation Example 7: Elemental analysis = (Analysis value) Carbon 47.9%, Nitrogen 1.85
%, chlorine 9.3%, fluorine 2164%, (theoretical value) carbon 47.7%, nitrogen 1.95%, chlorine 9.0%, fluorine 21.7%.

Infrared absorption analysis (c+n-1): 2900 (-C)
lx or -CH2-), 2300-2700 (-N
) (a) , 1100-1200 (-CF2- or -
CCHI->, 1700-1740(-COO-),
1430 (cyclohexyl).

Intrinsic viscosity [η]; 0.0133 (solvent: methanol, 35°C).

From the above analysis results, the obtained copolymer of the present invention has C
51 mol% units based on TFE, 2.2. It was found to consist of 30 mol % of units based on L3-tetrafluoropropyl vinyl ether and 29 mol % of units of the formula:

Preparation Example 12 Elemental analysis: (Analysis values) Carbon 53.1%, Nitrogen 2.8%
, chlorine 8.2%, fluorine 13.1%, (theoretical value) carbon 5
3.4%, nitrogen 2.6%, chlorine 8.1%, fluorine 13.
0%.

Infrared absorption analysis (cm-'): 3200-3400
(-OH), 2900 (-CII2-), 2300~
2700 (-Nil(CII2C83)3), 11
00-1200 (-CF2- or -cpca->, 1
700-1740 (-Coo-), 1430 (cyclohexyl).

Intrinsic viscosity [η]: 0.068 (solvent: methanol, 35°C).

From the above analysis results, the obtained copolymer of the present invention has C
It was found to consist of 52 mol % of units (+) based on TFH, 05 mol % of units based on n-octyl vinyl ether (0VE) and 43 mol % of units (n) of the formula +1. Note that the esterification rate is 100% and the neutralization degree is 100%.
%Met.

Reference preparation example 3 Elemental analysis: (Analysis value) Carbon 51.4%, Nitrogen 1.8%
, chlorine 9.7%, fluorine 15.4%, (theoretical value) carbon 5
1.2%, nitrogen 1.7%, chlorine 9.7%, fluorine 15.
6%.

Infrared absorption analysis (ca+-1): 3200-340
0 (-011), 2900 (-C112-), 230
0 to 2700 (-Nil(CII2CH3)3),
1100-1200 (-CF2- or -CFCI-)
, 1700-1740 (-COO-) , 143G (
cyclohexyl).

Intrinsic viscosity [η]: 0.15 (solvent: methanol, 35°C).

From the above analysis results, the obtained copolymer has CTPH+
, unit (+) 49 mol% based on 1m, IIBVEI:l
:Based unit (to) 19 mol%, VA based unit 1i
) 10 mol % and 22 mol % of the unit (n) of the formula: In addition, the esterification rate is 54%, and the neutralization degree is 100%.
Met.

[Margins below] The weights of the esterifying agent and neutralizing agent in the table are for the copolymer 10M
It is for.

Comparative Preparation Examples 1 to 4 Comparative copolymers were prepared in the same manner as Preparation Example 1, except that the monomers, esterifying agents, or neutralizing agents used in Preparation Example 1 were replaced with those shown in Table 2. Prepared.

[Margin below] Preparation Examples 1 to 12, Reference Preparation Examples 1 to 3, and Comparative Preparation Example 1
The copolymers obtained in steps 4 to 4 were subjected to infrared absorption analysis in the same manner as in Example 1 to determine the molar ratio of each unit.

The results are shown in Table 3 along with the esterification rate and neutralization degree.

[Margin below] Table 3 Test Examples 1 to 15 and Comparative Test Examples 1 to 4 Preparation Examples 1 to 4
12. Regarding the copolymers prepared in Reference Preparation Examples 1 to 3 and Comparative Preparation Examples 1 to 4, the dissolution stability when diluted with water was investigated, and it was found that Preparation Examples 1 to 12 and Reference Preparation Examples 1 to 3
The copolymer showed good dissolution stability, with a slight cloudiness even when diluted 10 times with water, but the copolymer precipitated when diluted about 2 times with comparative preparation example. Oops.

Test Examples IB to 30 The copolymer mixtures obtained in Preparation Examples 1 to 12 and Reference Preparation Examples 1 to 3 were added with methylolated melamine (Melan 620, manufactured by Hitachi Chemical Co., Ltd.) as a curing agent in the amounts shown in Table 4 ( However, after adding solid content (weight ratio) and mixing well, it was diluted to 25% by weight with a 1/1 water/ethanol mixture by weight. The resulting mixture was spray-coated onto a degreased aluminum plate with a width of 70 mm, a length of 150 mm, and a thickness of 1 mm. After drying at 80°C for 10 minutes, it was cured at 150°C for 30 minutes to give a film thickness of 10. A sample was obtained with a coating film of . This sample was examined for pencil hardness, adhesion to the base, gloss, stain resistance to oil-based ink, and boiling water resistance using the following methods. The results are shown in Table 4.

Pencil hardness: JIS K 5400G, 14 using a pencil scratch tester for paint film (manufactured by Toyo Seiki Seisakusho, pencil: Mitsubishi Uni)
I did it using this method. Indicates the pencil hardness at which dents appear in the paint film.

Use a cutter knife to cut 1111 square squares into the coating film that adheres to the base material.
A peel test was performed 10 times using cellophane adhesive tape, and the number of remaining squares was determined.

The 60° specular reflectance was measured using a gloss meter (VC-2PD manufactured by Nippon Denshoku Industries Co., Ltd.).

Stain resistance against oil-based inks 1clf of the paint film surface is made of ■Sakura crevasse.

After painting with Ventouch (red) and leaving it for 24 hours, it was wiped off with tissue paper impregnated with ethanol, and the stains remaining on the paint surface were examined with the naked eye. In the table, ◎ indicates that no stains remain at all, and O indicates that slight traces remain.

Boiling Water Resistance After immersing the sample in boiling water for 5 hours, the condition of the coating film was visually examined. In the table, ◎ means no change, ○ means slightly cloudy, X
indicates that blistering or peeling has occurred.

Comparative Test Example 5 An emulsion-type polytetrafluoroethylene paint (Polyflon Dispersion D-1 manufactured by Daikin Industries, Ltd.) was diluted with water to a concentration of 30% by weight and used in the test examples te to 30 above. It was spray painted on the same aluminum plate. After drying this at 80℃ for 10 minutes,
A sample having a coating film with a film thickness of 8ρ was obtained by baking at 0° C. for 15 minutes. This sample was examined for pencil hardness, adhesion to the substrate, gloss, stain resistance to oil-based ink, and boiling water resistance using the same methods as above. The results are shown in Table 4.

Test Example 31 and Comparative Test Example 6 CTPE/4PVE/IIBVE molar ratio 50/4
The same composition as used in Test Example 1G above was applied by spray onto a substrate having a fluororesin base coating film containing a 0/10(7) copolymer as a main component, and the mixture was heated at 80°C for 10 minutes.
A sample was obtained by drying and curing at 150° C. for 30 minutes.

Accelerated weathering test (Sunshine weather meter; due cycle, irradiation/dark-BO min/6
0 minutes, humidity 60%, black panel temperature 63℃, 300
The gloss retention rate was as good as 81%.

On the other hand, on the same base material as above, 100 parts by weight of a copolymer of methyl methacrylate/methacrylic acid/dimethylaminoethyl methacrylate in a molar ratio of 50/20/30, 6209 parts by weight of furan as a curing agent, and ethanol/water (in a weight ratio of A comparative sample was obtained by applying a composition consisting of 360 parts by weight of a 1/1) mixture in the same manner as above. When this comparative sample was subjected to an accelerated weathering test (under the same conditions as above), the gloss retention rate was significantly inferior at 34%.

[Effects of the invention] The copolymer of the present invention dissolves or disperses well in an aqueous medium even without a surfactant, and the coating film obtained from an aqueous paint containing it as a main component has a high hardness and a high degree of compatibility with the base material. Excellent adhesion, gloss, stain resistance, boiling water resistance, and weather resistance.

Patent applicant: Daikin Industries, Ltd.

Claims (1)

[Claims] 1 20 to 80 mol% of the structural unit represented by the formula: -CFX-CF_2-(i) (wherein, X represents chlorine or fluorine), and the formula: ▲ Numerical formula, chemical formula, There are tables, etc.▼(ii) (In the formula, R^1 is an alkylene group having 2 to 6 carbon atoms or a divalent alicyclic group having 4 to 10 carbon atoms, M is hydrogen, an alkali metal, NHR^2R^ 3R^4 groups [However, R^2, R^3
and R^4 are the same or different, hydrogen, carbon number 1-
6 alkyl group or a hydroxyalkyl group having 1 to 6 carbon atoms. ] or RH group [where R has 4 to 9 carbon atoms]
It is a nitrogen-containing cyclic compound. ], n represents an integer of 2 to 6. ), or 80 to 20 mol% of the structural unit represented by Structural unit or formula represented by an alkyl group having 1 to 12 carbon atoms, a monovalent alicyclic group having 4 to 10 carbon atoms, or a fluoroalkyl group having 2 to 10 carbon atoms, where k represents 0 or 1): ▲ There are mathematical formulas, chemical formulas, tables, etc.▼(iv) A fluorine-containing copolymer containing 40 mol% or less of any one of the structural units represented by (in the formula, j represents an integer from 2 to 6).