JPH02233749A - Fluororesin composition for aqueous coating and production thereof - Google Patents

Abstract

PURPOSE:To obtain a resin composition for aqueous coating excellent in film physical properties and dispersion stability by mixing a COOH-containing fluororesin having a specific value or above of acid value with a fluororesin fundamentally without any acid value in a specific proportion and dispersing the resultant mixture in an aqueous medium. CONSTITUTION:A fluororesin composition for aqueous coating, obtained by mixing (A) a reaction product prepared by reacting a COOH-containing fluororesin having >=5 acid value (solid substance), e.g. OH-containing fluororesin, with an acid anhydride having reactive double bond to provide a vinyl group-containing fluororesin and further reacting the resultant resin with COOH-containing vinyl monomers with (B) a fluororesin having <=2 acid value at (3:97)-(70:30) solid substance weight ratio, neutralizing at least part of COOH groups contained in the resultant mixture with a basic compound (preferably ammonia or volatile amine) and dispersing the neutralized mixture in an aqueous medium and having preferably 1-80, especially 5-40 total resin acid value (solid substance).

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a fluororesin composition for aqueous coatings that can form a coating film with excellent weather resistance and excellent dispersion stability, and its production. Regarding the law.

(Prior Art) Various synthetic resin paints have been developed for the purpose of surface protection and beautification. Fluororesin paints have attracted particular attention in recent years as they have long-term weather resistance. Fluororesin paints are composed of fluororesin, pigments, various additives, and organic solvents. In this conventional fluororesin configuration, since an organic medium is used as the medium, the solvent is present in the working atmosphere. This results in deterioration of the working environment, impairing human safety such as solvent poisoning of workers, and polluting the atmosphere.
Furthermore, since it is a flammable solvent, there is always a risk of fire or explosion.

In order to solve these problems, a method is known in which a fluororesin is synthesized by emulsion polymerization using an emulsifier (Japanese Patent Application Laid-Open No. 55-25412). However, with this method, it is difficult to use large amounts of highly polar monomers to carry out the emulsion polymerization reaction in water, and the resulting emulsion has problems with film-forming properties, and due to the residual emulsifier. However, it has the disadvantages of poor water resistance, corrosion resistance, adhesion, etc.
There were also problems with storage stability. As a means to eliminate such drawbacks of fluororesin emulsion resin, water-soluble acrylic resin, water-soluble alkyd resin,
A method of dispersing a fluororesin using a water-soluble resin such as a water-soluble maleated oil has been proposed (Japanese Patent Laid-Open No. 62-158
Publication No. 766). (Problem B to be solved by the invention) However, according to this method, the compatibility between the fluororesin and various water-soluble resins is insufficient, resulting in problems such as cloudiness of the resin film and poor gloss of the coating film. There is also the problem that the excellent features of the fluororesin may be impaired depending on the amount of the fluororesin used.

Although various studies and proposals have been made to make fluororesin water-based, the current situation is that nothing fully satisfactory has been achieved. As a result of extensive research to solve these problems, the present inventors have found that a fluororesin having an acid value higher than a predetermined value, that is, containing a carboxyl group,
It has been discovered that a fluororesin composition for aqueous coatings with excellent performance can be obtained by mixing a fluororesin that basically has no acid value in a predetermined ratio and dispersing this in an aqueous medium, and the present invention This is the completed version. The purpose of the present invention is to have excellent dispersion stability over time, good color saturation and transparency, excellent adhesion to substrates, and physical properties of the coating film such as water resistance and weather resistance that are no different from those of solvent-based fluororesins. The object of the present invention is to provide a fluororesin composition for aqueous coating that can form a film. Another object of the present invention is to provide a method for efficiently producing the above-mentioned fluororesin composition for aqueous coatings. (Means for Solving the Problems) In order to achieve the above object, the fluororesin composition for aqueous coating of the present invention contains a carboxyl group-containing fluororesin having an acid value (solid content) of 5 or more, and an acid value ( and a fluororesin whose solid content is 2 or less, and the solid content ratio is 3 = 97 to 70: 3.
It is made by mixing at a ratio of 0.0 and dispersing it in an aqueous medium. The amount of the carboxyl group-containing fluororesin having an acid value (solid content) of 5 or more is preferably in the range of 3 to 10111%, and particularly preferably in the range of 10 to 50% by weight. If the amount used does not reach 3% by weight, the dispersion stability of the fluororesin composition of the present invention in an aqueous medium deteriorates, which is not preferable. Further, even if the amount used exceeds 70%, no improvement in the dispersion effect is observed. The total resin acid value (solid content) is preferably 1 to 80, and 5 to 40.
is particularly preferred. If the acid value is less than 1, the dispersibility and stability will be poor, and if it exceeds 80, the resulting film will have poor water resistance and alkali resistance. Of course, the value of the total resin acid value (solid content) is adjusted so that it is derived from a carboxyl group-containing fluororesin having an acid value (solid content) of 5 or more. As the carboxyl group-containing fluororesin having an acid value (solid content) of 5 or more used in the present invention, for example, a fluororesin modified with a carboxyl group-containing vinyl monomer and other vinyl monomers can be used. This vinyl-modified fluororesin is, for example, (a) hydroxyl group-containing fluororesin 90~
99.9% by weight and 0.0% by weight of an acid anhydride having a reactive unsaturated double bond. 40 to 95 parts by weight of a vinyl group-containing reaction product obtained by reacting 1 to 10% by weight with (b) 5 to 60 parts by weight of a polymerizable vinyl monomer containing a carboxyl group-containing vinyl monomer. It can be produced by carrying out a copolymerization reaction in the presence of an agent. As the hydroxyl group-containing fluororesin used in the above manufacturing method,
Any conventionally known method can be used, but for example,
Used is one obtained by copolymerizing a fluoroolefin and a hydroxyl group-containing monomer or a monomer having a group convertible to a hydroxyl group by hydrolysis or the like as essential components, and further copolymerizing other vinyl monomers.

Examples of fluoroolefins include vinyl butylene, vinylidene butylene, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, promotrifluoroethylene, pentafluoropropylene, hexafluoropropylene, trifluoromethyl trifluorovinyl ether, and pentafluoroethylene. Ethyl trifluorovinyl ether or heptafluoroprovir
Perfluoroalkyl perfluorovinyl ethers such as trifluorovinyl ether are typical, and use of tetrafluoroethylene, vinylidene butylene, chlorotrifluoroethylene, or hexafluoropropylene is particularly preferred. These fluoroolefin monomers may be used alone or in combination of two or more.

Examples of hydroxyl group-containing monomers include 2-hydroxyethyl vinyl ether, 3-hydroxypyruvinyl ether, 2-hydroxypyruvinyl ether, 4-hydroxybutylvinyl ether, 3-hydroxybutylvinyl ether, 2-hydroxy-2-methylpropylvinyl ether, 5-hydroxypentyl vinyl ether, 6
Vinyl ethers containing water HM such as -hydroxyhexyl vinyl ether are preferably used.

Examples of monomers having a group convertible to a hydroxyl group by hydrolysis etc. include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriproxysilane, vinylmethyldiethoxysilane, vinyltris(β-methoxyethoxy)silane, and allyltrimethoxysilane. Silane, trimethoxysilyl ethyl vinyl ether, methyldimethoxysilylethyl vinyl ether, trimethoxysilyl pyruvinyl ether, triethoxysilyl pyruvinyl ether, methyldimethoxysilylprobyl vinyl ether, γ-(meth)acryloyloxy pyrutrimethoxysilane Examples include monomers containing a hydrolyzable silyl group such as γ-(meth)acryloyloxypyltriethoxysilane and γ-(meth)acryloyloxypylmethyldimethoxysilane. Other heptanomers include alkyl vinyl ether necks or substituted alkyl vinyl ethers, cycloalkyl vinyl ethers, carboxylic acid vinyl esters, α-olefins, various halogenated olefin necks excluding fluoroolefins, aromatic vinyl compounds, methacrylic acid. Typical examples include esters, acrylic esters, etc.Furionate K-700, manufactured by Dainippon Ink & Chemicals, etc., is a typical example of a hydroxyl group-containing fluororesin. can be mentioned.

Any acid anhydride having a reactive unsaturated double bond can be used as long as it has a reactive unsaturated double bond, but it is particularly preferable to use acrylic anhydride and/or methacrylic anhydride. The ratio of the hydroxyl group-containing fluororesin and the acid anhydride having a reactive unsaturated double bond is as follows:
Weight ratio: 90:10-99. 9: o. 1, preferably 95:5 to 99. ago. A range of 2 is particularly preferred.

The usage ratio of acid anhydride with reactive unsaturated double bond is 0
．． If it does not reach 1% by weight, it is not preferable because the dispersion stability of the carboxyl group-containing modified polymer in an aqueous medium tends to be poor. If the proportion of the acid anhydride having a reactive unsaturated double bond exceeds 10% by weight, the carboxyl group-modified polymer tends to have a high molecular weight during polymerization and tends to gel, which is not preferable.

When the reaction is carried out using, for example, methacrylic anhydride as the acid anhydride having this reactive unsaturated double bond, -QC-C-CH. The polymerizable vinyl monomer used in the copolymerization reaction with the vinyl group-containing reactant to obtain a reactant containing a vinyl group represented by 0 CH, is a polymerizable vinyl monomer containing a carboxyl group-containing vinyl monomer. . Although there is no particular restriction on the content of the carboxyl group-containing vinyl heptanomer, it is preferable that the content be at least about 5% by weight. If the content of the carboxyl group-containing vinyl monomer is too small, the dispersion stability of the resin in an aqueous medium, the adhesion of the coated film to metals, and the solvent resistance tend to deteriorate, which is undesirable.

Examples of carboxyl group-containing vinyl monomers include:
Acrylic acid, methacrylic acid, crotonic acid, itaconic acid,
Examples include maleic acid and fumaric acid.

Other vinyl monomers include, for example, styrene,
Styrenic heptanomers such as vinyltoluene, 2-methylstyrene, L-butylstyrene, chlorstyrene; methyl acrylate, ethyl acrylate, isoprobyl acrylate, n-butyl acrylate, isobutyl acrylate,
n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate,
Acrylic acid esters such as n-octyl acrylate, decyl acrylate, dodecyl acrylate; methyl methacrylate, probyl meccrylate, n-butyl methacrylate, isobutyl meccrylate, n-amyl methacrylate,
Methacrylic acid esters such as n-hexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, decyl methacrylate, dodecyl methacrylate; hydroxyethyl acrylate, hydroxypupyl acrylate, hydroxyethyl methacrylate, Examples thereof include hydroxyl group-containing monomers such as hydroxybutylene methacrylate; N-2-substituted (meth)acrylic monomers such as N-methylol (meth)acrylamide and N-butoxymethyl (meth)acrylamide; In addition, carboxylic acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl versatinoxate, vinyl laurate, vinyl stearate, vinyl benzoate, or methyl, ethyl, n-propyl, isobrobyl, n Examples thereof include vinyl ethers having an alkyl group such as -butyl, isobutyl, L-butyl, isoamyl, n-hexyl, n-octyl, and 2-ethylhexyl, or a substituent-containing alkyl group such as hydroxyethyl and hydroxybutyl.

As described above, the vinyl-modified fluororesin is produced by solution polymerizing the vinyl group-containing reactant and the polymerizable vinyl monomer.

The ratio of the vinyl group-containing reactant to the polymerizable vinyl monomer is preferably in the range of 40:60 to 95:5 by weight.

If the proportion of the vinyl group-containing reactant used is less than 40% by weight, it is not preferable because the various properties of the fluorine copolymer may not be utilized. If the proportion of the vinyl group-containing reactant used exceeds 95% by weight, the carboxyl group-containing modified polymer tends to become difficult to self-emulsify, which is not preferable.

Examples of the polymerization initiator used in the copolymerization reaction between the vinyl group-containing reactant and the polymerizable vinyl monomer include common radical polymerization initiators such as azobisisobutyronitrile and penzoyl peroxide.

Examples of organic solvents used in the copolymerization reaction include alcohols such as methanol, ethanol, propanol, and butanol; ethers such as methylcellosolve, ethylcellosolve, provilcellosolve, butylcellosolve, methylrubitol, and ethylcarbitol. Alcohols; examples include ketone necks such as methyl ethyl ketone and diisobutyl ketone, and aromatic hydrocarbons such as toluene.

The resin solid content acid value of the copolymer of the vinyl group-containing fluororesin and the polymerizable vinyl monomer is in the range of 5 to 150, especially lO
It is preferable that it is in the range of ~80. If the resin solid content acid value is 5 or less, the dispersibility will be poor, and if it is 150 or more, the water resistance will tend to decrease, which is not preferable.

Examples of the fluororesin whose (oral) acid value (solid content) used in the present invention is 2 or less include Fluonate K-70.
0 (manufactured by Dainippon Ink and Chemicals, for clear use), Fluonate K-701 (for colored enamel), Fluonate K-600 (lunker type, fluororesin hard type), Fluonate K-601 (for colored enamel), Lacquer type fluororesin soft type) etc. can be used.

The fluororesin composition for aqueous coating of the present invention has (a) an acid value (
A carboxyl group-containing fluororesin with a solid content of 5 or more and a fluororesin with a (mouth) acid value (solid content) of 2 or less are mixed at a solid content ratio of 3:97 to 70:30. ,
It is produced by neutralizing at least a portion of the carboxyl groups contained in this mixture with a basic compound and then finely dispersing this mixture in water.

The basic compound used here is preferably ammonia or a volatile amine. Inorganic bases are not preferred because they remain in the coating film and impair water resistance.

Examples of the amine that can be used include alkyl amines such as trimethylamine, triethylamine, and butylamine; alcohol amines such as dimethylaminoethanol, diethanolamine, and aminomethylpropanol; and morpholine.

Further, polyvalent amines such as ethylenediamine and diethylenetriamine can also be used.

In the present invention, the aqueous medium means water alone or in a mixture with a hydrophilic organic solvent, in which at least 10% by weight is water. Examples of hydrophilic organic solvents include methanol, ethanol, n-propanol, isopropanol,
Alkyl alcohols such as n-butanol, Sec-butanol, Lert-butanol, isobutanol, etc. Glycol ethers such as methyl cellosolve, ethyl cellosolve, provil cellosolve, butyl cellosolve, hexyl cellosolve, methyl rubitol, ethyl rubitol, etc.: methyl cellosolve acetate , glycol ether esters such as ethyl cellosolve acetate; in addition, dioxane, dimethylformamide, dianetaton alcohol, tetrahydrofuran, etc. can be used.

The fluororesin composition for aqueous coating of the present invention has very good dispersion stability. If it is necessary to further reduce the amount of organic solvent contained, use a solvent with a low boiling point such as acetone or methyl ethyl ketone, or a solvent that is azeotropic with water such as butanol or butyl cellosolve as a reaction solvent or resolution aid.
By dispersing it in an aqueous medium and then distilling it under normal pressure or reduced pressure, it is possible to stably and easily obtain an aqueous fluororesin composition containing a low amount of organic solvent.

It is also possible to add a solvent, a surfactant, and an antifoaming agent to the aqueous coating fluororesin composition of the present invention, if necessary, to improve the coating properties. Furthermore, it is also possible to add an amine resin, phenol resin, blocked isocyanate, etc. to the fluororesin composition for aqueous coating of the present invention as a curing agent.

The aqueous fluororesin composition for coating of the present invention can be used as it is as a clear coating agent, but it can also be used as a clear coating agent. It can also be used as a mixed paint. In making a paint, various equipment commonly used for making a paint can be used, such as a ball mill, a paint shaker, a sand mill, a jet mill, a Miki roll, and a kneader. At this time, pigments, dispersion stabilizers, viscosity modifiers, leveling agents, gelling inhibitors, ultraviolet absorbers, etc. can also be added.

As the coating method, conventionally known methods such as mouth coating, electrodeposition coating, flow coating, spray coating, and brush coating are used.

The fluororesin composition for water-based coatings of the present invention can be used in a wide range of applications from forced drying at room temperature to baking coating using a curing agent such as melamine or blocked isocyanate.
It is preferable to use the baking condition at 00 to 250°C for 10 seconds to 30 minutes.

The fluororesin composition for aqueous coating of the present invention has excellent workability, excellent surface hardness and gloss, and flexibility.
It can provide a coating film with excellent solvent resistance, stain resistance, and weather resistance under mild conditions, and can be used not only as a baking paint for colored steel plates, colored aluminum plates, aluminum sashes, etc. It is also useful as an air-drying paint that can be applied on-site. The material of the base material is not limited to metals such as iron, aluminum, steel, or alloys thereof, such as stainless steel and brass, but also inorganic materials such as glass, cement, concrete, FRB, polyethylene, polypropylene, and ethylene-vinyl acetate copolymer. Coalescence, nylon, acrylic, polyester, ethylene-bolivinyl alcohol copolymer, vinyl chloride,
Plastics such as vinylidene chloride and polycarbonate,
It is also useful for coating organic materials such as wood, and is particularly useful as a top coat for coated objects that have another base coat. They are also useful in certain applications such as aluminum pools, exterior colored glass, and cement roofs. (Examples) The present invention will be explained in more detail with reference to Examples below, but it goes without saying that the present invention is not limited to the description of these Examples. In addition, "r part" or "r%" in the examples indicates "part by weight" or "rTi amount %", respectively.

Synthesis example l First step: Introduction of vinyl group into fluororesin ■Fluonate K-700 200.0
Part■Methacrylic anhydride－・・・・・・・・・－・－・・
・−・−・・−・−・・・・−・・−・・4.0 parts■Triethylamine・−・・・・・・・・・・・・・・・・・・・
・・・・・・・・・－・・・・・・0.5 parts (in the above composition, ■Fluoney} K-700 is a hydroxyl group-containing fluororesin manufactured by Dainippon Ink & Chemicals ■, with a nonvolatile content of 50%) , the solid content has a hydroxyl value of 48.) ■, ■, and ■ are placed in a 4-hole flask purged with nitrogen gas, and the contents are heated to 80°C without stirring, and stirred at the same temperature for 2 hours to produce vinyl. A group-containing reactant was obtained.

Second step: Synthesis of vinyl-modified fluororesin ■The above vinyl group-containing fluororesin 1...204.5 parts■Isopropanol--------------------------------------・
・・・・・・・・・・・・ll7 parts ■Methacrylic acid・−
・・・・−・・・・・・・・・−・・・・−
・・・・・・・・・・・・7.0 parts ■Methacrylic acid n-
Butyl・・・・・・・・・−・・・・・・・・・・・・・・・・・・
... 32 parts ■ Perbutyl 0 ......
・・・－・・・・・・・・・・・・・・・・・・・・・
......2 parts (in the above composition, ■ Barbyl-0 is [-butylperoxy-2-ethylhexanate (radical polymerization initiator) manufactured by NOF ■) ■, ■,
After uniformly mixing ■, ■, and ■, lOO of the mixed liquid
4 days in a flask that had been replaced with nitrogen gas, and heated to 80°C.
The remaining mixture was gradually added dropwise over a period of 4 hours while keeping the temperature at that temperature, and the mixture was further stirred at the same temperature for 4 hours to obtain a vinyl-modified fluororesin. The properties of this composite were measured and shown in Table 1. Synthesis Example 2 A vinyl-modified fluororesin was obtained in the same manner as in Synthesis Example 1, except that (1) methacrylic acid was changed to 20 parts, (2) n-butyl methacrylate was changed to 24 parts, and (2) 20 parts of methyl methacrylate were newly added. The properties of this composite were measured and shown in Table 1. Synthesis Example 3 A vinyl-modified fluororesin was obtained in the same manner as in Example 1, except that (1) methacrylic anhydride was changed to 8 parts, (2) methacrylic acid was changed to 88 parts, and (2) n-butyl methacrylate was changed to 4 parts. The properties of this composite were measured and shown in Table 1. (Margins below) Table 1 Example 1 75 parts of vinyl-modified fluororesin (solid content 30 parts) of Synthesis Example 1 and Fluonate K-700 (Dainippon Ink Chemical Co., Ltd.)
fluororesin containing hydroxyl groups) 140 parts (solid content 70 parts)
into a four-necked flask purged with nitrogen gas, heat the contents to 60°C without stirring, add 2.2 parts of triethylamine at the same temperature, and after uniformly mixing, add 150 parts of ion-exchanged water dropwise over 30 minutes. An aqueous dispersion was obtained. The resulting dispersion was further concentrated under reduced pressure to obtain a fluororesin composition for aqueous coatings having the properties shown in Table 2.

Example 2 62.5 parts of vinyl-modified fluororesin of Synthesis Example 2 (solid content 2
5 parts) and Fluone} K-600 (manufactured by Dainippon Ink & Chemicals, lacquer type fluororesin hard type) 150
(solid content: 75 parts) and 3.5 parts of t+4 ethylamine.
8 parts were added to obtain an aqueous dispersion in the same manner as in Example 1. Is this obtained dispersion further depressurized? The second image after ls shrinking
A fluororesin composition for aqueous coating having the properties shown in the table was obtained.

Example 3 125 parts of vinyl-modified fluororesin of Synthesis Example 2 (solid content 50
) and Fluonate K-600 (manufactured by Dainippon Ink & Chemicals ■, lacquer type fluororesin hard type) (solid content: 50 parts), 7.5 parts of triethylamine was added, and an aqueous solution was prepared in the same manner as in Example 1. A dispersion was obtained. The resulting dispersion was further concentrated under reduced pressure to obtain a fluororesin composition for aqueous coatings having the properties shown in Table 2.

Comparative Example 1 5 parts of vinyl-modified fluororesin (solid content 2 parts) of Synthesis Example 1 and Fluonate K-700 (manufactured by Dainippon Ink & Chemicals,
An aqueous dispersion was obtained in the same manner as in Example 1 by using 196 parts (solid content: 95 parts) of fluororesin containing hydroxyl groups and adding 0.4 parts of triethylamine. The resulting dispersion was further concentrated under reduced pressure to obtain a fluororesin composition for aqueous coatings having the properties shown in Table 2. Comparative Example 2 125 parts of vinyl-modified fluororesin of Synthesis Example 3 (solid content 50
) and Fluone} K-600 (manufactured by Dainippon Ink & Chemicals, lacquer type fluororesin hard type) 100 parts (
An aqueous dispersion was obtained in the same manner as in Example 1 by adding 20 parts of triethylamine (solid content: 50 parts). The resulting dispersion was further concentrated under reduced pressure to obtain a fluororesin composition for aqueous coatings having the properties shown in Table 2.

Table 2 (In Table 2, the evaluation of dispersion state and stability is ◎(
Very good), O (good), MiΔ (poor), × (poor),
xx (extremely poor). ) As is clear from Table 2, Examples 1 to 3 all had good dispersibility and stability.

In Comparative Example 1, the amount of carboxyl group-containing fluororesin used was small and the acid value of the total resin solid content was low, but both the dispersion state and stability were poor.

Moreover, Comparative Example 2 is a case where the total resin solid content acid value is high.

In this case, the decomposition state and stability were both good, but as shown in Table 3, the alkali resistance and water resistance in the coating film state were poor, and the accelerated weathering resistance was also poor. Test Examples The coating performance of the compositions obtained in Examples 2 and 3 and Comparative Example 2 was measured, and the results are shown in Table 3. Comparative Example 3 shows the coating film performance using solvent-based fluororesin Fluonate K-600 (product of Dainippon Ink & Chemicals). Test conditions Fee: R TiOz [CR 93 Ishihara Sangyo ■]
PWC 35% Base material: Zinc phosphate treated W4 board Bonde #44 treated dull 0.6mm thick Painting: Air spray (Ford Cup Nα4RT13
~14 seconds dull steel plate) Painting: Air spray Table 3, 2, Table 3, 1 (In Table 3, performance evaluations are ◎ (no abnormality), ○ (
Good), Δ (poor), and × (poor).

Further, the conditions for measuring accelerated weathering resistance are as follows.

Test equipment: Dewvanel light control weather meter (manufactured by Suga Test Instruments) Conditions: UV irradiation at 70°C for 8 hours. ．． Wem 50°C x 4
Pigment used: Taipeiku CR-93, 40 35%) As shown in Table 3, the coating film performance of the fluororesin composition for water-based coatings of the present invention is
-600), which was found to be good. (Effects of the Invention) As described above, the fluororesin composition for aqueous coating of the present invention has excellent dispersion stability over time, good chroma and transparency, and excellent adhesion to the substrate material. It has the effect of producing a film with physical properties such as water resistance and weather resistance that are comparable to those of solvent-based fluororesins. By achieving such effects, the fluororesin composition for water-based coatings of the present invention is particularly suitable for exterior paints.

Furthermore, the method of the present invention has the advantage that the fluororesin composition for aqueous coatings of the present invention having the above-mentioned performance can be efficiently produced.

Claims (4)

[Claims] (1) (a) A carboxyl group-containing fluororesin with an acid value (solid content) of 5 or more and (b) a fluororesin with an acid value (solid content) of 2 or less at a solid content ratio of 3:97. ~70:3
A fluororesin composition for an aqueous coating, characterized in that it is mixed at a ratio of 0.0 and dispersed in an aqueous medium. (2) A claim in which the total resin acid value (solid content) is 1 to 80 (
1) The fluororesin composition for aqueous coating as described above. (3) (a) Carboxyl group-containing fluororesin with an acid value (solid content) of 5 or more and (b) fluororesin with an acid value (solid content) of 2 or less in a solid content ratio of 3:97. ~70:3
Production of a fluororesin composition for aqueous coating, characterized in that the mixture is mixed at a ratio of 0.0 and at least a part of the carboxyl groups contained in this mixture is neutralized with a basic compound, and then this mixture is finely dispersed in water. Law. (4) A claim in which the total resin acid value (solid content) is 1 to 80 (
3) Method for producing a fluororesin composition for aqueous coating as described.