JP2014088495A - Aqueous fluororesin composition, aqueous fluorine paint, and article coated by the paint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous fluororesin composition which can be produced by a simple method, can form a highly weather resistant coating film, and is excellent in long-term storage stability.SOLUTION: An aqueous fluororesin composition contains a fluororesin aqueous dispersion (A) and a specific organic solvent (B) having a hydroxyl group. The fluororesin aqueous dispersion (A) is obtained through a first step of performing a copolymerization reaction of a specific monomer mixture (I), a second step of adding a specific monomer mixture (II) to a reactant obtained in the first step and further performing copolymerization reaction to obtain a fluorine copolymer (A'), and a third step of neutralizing the carboxyl groups of the fluorine copolymer (A') with a basic compound and dispersing it in an aqueous medium. An equivalent ratio of the hydroxyl group (OHB) in the organic solvent (B) to the hydroxyl group (OHA') in the fluorine copolymer (A') is 0.2 or more.

Description

  The present invention relates to an aqueous fluororesin dispersion in which a fluorocopolymer is dispersed in an aqueous medium, an aqueous fluorine paint using this dispersion, and an article coated with the paint.

  A paint using a fluororesin is widely used as a material for forming a protective coating such as an architectural paint or an automobile top coat because it has excellent weather resistance, chemical resistance, and the like. In particular, a two-part curable coating resin composition containing a hydroxyl group-containing fluororesin, a hydroxyl group-reactive curing agent, and an organic solvent has excellent coating film properties (see, for example, Patent Document 1). .)

  However, the two-component curable coating resin composition described in Patent Document 1 includes aromatic solvents such as toluene and xylene, ester solvents such as ethyl acetate and butyl acetate, and ketones such as methyl ethyl ketone and methyl isobutyl ketone. Since it contains an organic solvent (strong solvent) with relatively high solubility, such as a solvent, it erodes the painted surface and is difficult to use for repairing the coating. In addition, these organic solvents have a large environmental load, and in recent years, their use has been difficult from the viewpoint of environmental friendliness.

  For this reason, powder coating resins and aqueous coating resin resins by emulsion polymerization have been developed that have low erosion on the painted surface and low environmental impact. However, the resin for powder coatings has a problem that it is not suitable for on-site construction because high temperature baking is required to obtain a coating film. In addition, a method of producing an aqueous fluororesin using an emulsion polymerization method is known, but this emulsion polymerization type aqueous fluororesin is not sufficient in room temperature film-forming property and remains in the coating film after the coating film is prepared. The water resistance is reduced due to the emulsifier, or the traces made by washing the emulsifier with water become pores, and the coating film is eroded from there, and the weather resistance that is an advantage of fluororesin is There were also problems that could not be fully utilized.

  In order to solve the problems of the emulsion polymerization type aqueous resin, a self-dispersion type (dispersion type) aqueous fluororesin that does not use an emulsifier that affects water resistance has been proposed (for example, see Patent Document 2). This self-dispersing aqueous fluororesin is obtained by introducing an acid group such as a carboxyl group into the fluororesin and neutralizing the acid group with a basic compound to impart self-dispersibility in an aqueous medium. . This self-dispersing water-based fluororesin can be applied on-site, has excellent film-forming properties at room temperature, and has excellent mechanical stability. Therefore, there has been a problem that the weather resistance decreases as the water resistance of the coating film decreases.

  Proposal to improve the dispersibility of fluororesin aqueous dispersion by mixing and dispersing components with many acid groups and components with few acid groups as a method to improve water dispersion stability of fluororesins with few acid groups (For example, refer to Patent Document 3). However, in this method, a compound having an acid group such as methacrylic acid and an unsaturated group is esterified with the hydroxyl group of the fluororesin to introduce an unsaturated group into the resin, and acrylic acid is further added to the unsaturated group. It is necessary to introduce a graft chain by copolymerizing a monomer having an acid group such as acid or methacrylic acid with a (meth) acrylic acid ester, and there is a problem that the operation for producing the fluororesin becomes complicated. There is also a problem that the storage stability of the fluororesin aqueous dispersion is low.

Japanese Examined Patent Publication No. 6-062910 JP-A-8-337620 Japanese Patent Laid-Open No. 2-233749

  The problem to be solved by the present invention is to provide an aqueous fluororesin composition that can be produced by a simple method, can form a highly weather-resistant coating film, and is excellent in long-term storage stability. It is to be. Another object of the present invention is to provide an aqueous fluorine paint containing the composition and an article coated with the paint.

  As a result of intensive studies to solve the above problems, the present inventors have obtained a basic compound from a fluorine copolymer having a carboxyl group obtained by copolymerizing a monomer mixture having a different composition in two stages. The aqueous fluororesin composition containing the fluororesin aqueous dispersion dispersed in an aqueous medium and the organic solvent (B) having a hydroxyl group in a specific ratio after neutralizing with an aqueous medium has a highly weather-resistant coating film. It has been found that it can be formed and is excellent in storage stability in the long term, and the present invention has been completed.

That is, the present invention copolymerizes a monomer mixture (I) essentially comprising a fluoroolefin compound (a1), a vinyl monomer (a2) having a hydroxyl group and a vinyl monomer (a3) having a carboxyl group. The first step of
To the reaction product obtained in the first step, a monomer mixture (II) essentially comprising a fluoroolefin compound (a1) and a vinyl monomer (a2) having a hydroxyl group is added, and a copolymerization reaction is further performed. A second step of obtaining a fluorine copolymer (A ′);
A fluororesin aqueous dispersion (A) obtained by a third step of neutralizing a carboxyl group of the fluorocopolymer (A ′) with a basic compound and dispersing in a water medium When,
The organic solvent (B) having a hydroxyl group is converted into an equivalent ratio (OHB / OHA ′) of the hydroxyl group (OHB) in the organic solvent (B) and the hydroxyl group (OHA ′) in the fluorine copolymer (A ′). However, it is related with the water-based fluororesin composition contained in the range used as 0.2 or more.

A first step of copolymerizing a monomer mixture (II) essentially comprising a fluoroolefin compound (a1) and a vinyl monomer having a hydroxyl group (a2);
The reaction mixture obtained in the first step is a monomer mixture (I1) essentially comprising a fluoroolefin compound (a1), a vinyl monomer (a2) having a hydroxyl group and a vinyl monomer (a3) having a carboxyl group. ) And further copolymerization reaction to obtain a fluorine copolymer (A ′),
A fluororesin aqueous dispersion (A) obtained by a third step of neutralizing a carboxyl group of the fluorocopolymer (A ′) with a basic compound and dispersing in a water medium When,
The organic solvent (B) having a hydroxyl group is converted into an equivalent ratio (OHB / OHA ′) of the hydroxyl group (OHB) in the organic solvent (B) and the hydroxyl group (OHA ′) in the fluorine copolymer (A ′). However, it is related with the water-based fluororesin composition contained in the range used as 0.2 or more.

  Furthermore, this invention relates to the water-based fluorine paint using the said water-based fluorine resin composition, and the article coated with this paint.

  The aqueous fluororesin composition of the present invention is dispersed in an aqueous medium having a low environmental load without using an emulsifier, and can form a highly weather-resistant coating film by drying at room temperature, and has excellent mechanical stability. In addition, it has excellent long-term storage stability. Therefore, it can be used for an aqueous fluorine paint. Further, the water-based fluorine paint using the water-based fluorine resin composition of the present invention has high weather resistance, light resistance, and chemical resistance, like the solvent-based fluorine paint, so that, for example, it is exposed to direct sunlight and has particularly high weather resistance. It is useful as a paint to form a protective coating on the roof of general buildings that require high properties and the exterior of factory buildings in complex areas where high chemical durability is required.

  The aqueous fluororesin composition of the present invention is an aqueous fluororesin composition containing an aqueous fluororesin dispersion (A) and an organic solvent (B) having a hydroxyl group.

  First, the said fluororesin aqueous dispersion (A) is demonstrated. The fluororesin aqueous dispersion (A) can be obtained by the following two embodiments.

The first embodiment is a copolymerization reaction of a monomer mixture (I) essentially comprising a fluoroolefin compound (a1), a vinyl monomer (a2) having a hydroxyl group and a vinyl monomer (a3) having a carboxyl group. The first step of
To the reaction product obtained in the first step, a monomer mixture (II) essentially comprising a fluoroolefin compound (a1) and a vinyl monomer (a2) having a hydroxyl group is added, and a copolymerization reaction is further performed. A second step of obtaining a fluorine copolymer (A ′);
This is a method of obtaining a fluororesin aqueous dispersion (A) through a third step of neutralizing the carboxyl group of the fluorocopolymer (A ′) with a basic compound and dispersing it in an aqueous medium.

The second aspect is a first step in which a monomer mixture (II) essentially comprising the fluoroolefin compound (a1) and the vinyl monomer (a2) having a hydroxyl group is copolymerized,
The reaction mixture obtained in the first step is a monomer mixture (I1) essentially comprising a fluoroolefin compound (a1), a vinyl monomer (a2) having a hydroxyl group and a vinyl monomer (a3) having a carboxyl group. ) And further copolymerization reaction to obtain a fluorine copolymer (A ′),
This is a method of obtaining a fluororesin aqueous dispersion (A) through a third step of neutralizing the carboxyl group of the fluorocopolymer (A ′) with a basic compound and dispersing it in an aqueous medium.

  The said fluoro olefin compound (a1) is a compound which has a carbon-carbon unsaturated double bond, and the fluorine atom has couple | bonded with the carbon atom which forms this double bond. Examples of the fluoroolefin compound (a1) include vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, bromotrifluoroethylene, chlorotrifluoroethylene, pentafluoropropylene, hexafluoropropylene, and fluoroalkyltrifluoro. Examples include vinyl ether. Among these, tetrafluoroethylene, chlorotrifluoroethylene, and hexafluoropropylene are preferable because of excellent weather resistance, room temperature film-forming property, and the like. Moreover, these fluoroolefin compounds (a1) can be used alone or in combination of two or more.

  The vinyl monomer (a2) is a compound having a hydroxyl group and a polymerizable carbon-carbon unsaturated double bond. Examples of the vinyl monomer (a2) include 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 2-hydroxy-2-methylpropyl vinyl ether, and 6-hydroxy. Hydroxyalkyl vinyl ether compounds such as hexyl vinyl ether and cyclohexanedimethanol monovinyl ether; Hydroxyallyl ether compounds such as ethylene glycol allyl ether and diethylene glycol allyl ether; Hydroxy such as 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate Examples include alkyl (meth) acrylate compounds. Among these, 2-hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether are preferable because of excellent copolymerizability and industrial availability. Moreover, these vinyl monomers (a2) can be used alone or in combination of two or more.

  In the present invention, “(meth) acrylate” refers to one or both of methacrylate and acrylate, and “(meth) acrylic acid” refers to one or both of methacrylic acid and acrylic acid.

  The vinyl monomer (a3) is a compound having a carboxyl group and a polymerizable carbon-carbon unsaturated double bond. Examples of the vinyl monomer (a3) include (meth) acrylic acid, ω-carboxy-polycaprolactone monoacrylate, crotonic acid, 3-butenoic acid, 4-pentenoic acid, 2-hexenoic acid, and 3-hexenoic acid. 5-hexenoic acid, 2-heptenoic acid, 3-heptenoic acid, 6-heptenoic acid, 3-octenoic acid, 7-octenoic acid, 2-nonenoic acid, 3-nonenoic acid, 8-nonenoic acid, 9-decenoic acid Monomers having one carboxyl group such as 10-undecenoic acid, 3-allyloxypropionic acid and allyloxyvaleric acid; monomers having two carboxyl groups such as itaconic acid, maleic acid and fumaric acid; fumaric acid Monomethyl, monoethyl fumarate, monobutyl fumarate, monoisobutyl fumarate, mono-t-butyl fumarate, monohexyl fumarate, monoo fumarate Chill, mono-2-ethylhexyl fumarate, monomethyl maleate, monoethyl maleate, monobutyl maleate, monoisobutyl maleate, mono-t-butyl maleate, monohexyl maleate, monooctyl maleate, mono-2-maleate Monoalkyl ester of monomer having two carboxyl groups such as ethylhexyl, monomethyl itaconate, monoethyl itaconate, monobutyl itaconate, monoisobutyl itaconate, monohexyl itaconate, monooctyl itaconate, mono-2-ethylhexyl itaconate Compounds: monovinyl compounds of dicarboxylic acids such as monovinyl adipate, monovinyl succinate and monovinyl maleate. These vinyl monomers (a3) can be used alone or in combination of two or more.

  Among the above vinyl monomers (a3), the storage stability of the aqueous fluorocopolymer dispersion of the present invention is further improved, so the number of atoms between the carboxyl group and the vinyl group (carboxyl group and vinyl group) Is not added.) Is preferably a monomer of 4 or more, more preferably in the range of 6-20, and even more preferably in the range of 8-15. As such a vinyl monomer (a3), 3-allyloxypropionic acid (number of atoms between carboxyl group and vinyl group: 4), 10-undecenoic acid (number of atoms between carboxyl group and vinyl group) 8), ω-carboxy-polycaprolactone monoacrylate (having two repeating units of caprolactone; 14 atoms between the carboxyl group and the vinyl group).

  In addition to the vinyl monomers (a2) and (a3), a vinyl monomer (a4) having no carboxyl group or hydroxyl group may be used as a raw material for the fluorine copolymer (A ′). . Examples of the vinyl monomer (a4) include 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, and n-hexyl. Alkyl vinyl ether compounds such as vinyl ether, n-octyl vinyl ether, 2-ethylhexyl vinyl ether, dodecyl vinyl ether, tridecyl vinyl ether, hexadecyl vinyl ether and octadecyl vinyl ether; cycloalkyl vinyl ether compounds such as cyclohexyl vinyl ether; aralkyl vinyl ether compounds such as benzyl vinyl ether and phenethyl vinyl ether Vinyl ether monomer such as acetic acid Nyl, vinyl propionate, vinyl caproate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate vinyl ester compounds, vinyl pivalate, 2-ethylhexanoic acid Vinyl ester compounds of branched carboxylic acids such as vinyl, vinyl neononanoate and vinyl neodecanoate; vinyl ester compounds of cyclic aliphatic carboxylic acids such as vinyl cyclohexanecarboxylate; vinyl benzoate, vinyl tert-butylbenzoate, etc. Vinyl ester compounds of aromatic carboxylic acids; Olefin compounds such as ethylene and propylene; Halogenated olefin compounds such as vinyl chloride and vinylidene chloride; Allyl ether compounds such as ethyl allyl ether and butyl allyl ether; Allyl acetate and propio Allyl ester compound allyl and the like; methyl (meth) acrylate, butyl (meth) acrylate, etc. (meth) and the like alkyl ester of acrylic acid. By copolymerizing these vinyl monomers (a4) with the vinyl monomers (a2) and (a3), compatibility with other paint components is improved when an aqueous fluorine paint is used. preferable. Among these vinyl monomers (a4), ethyl vinyl ether and cyclohexyl vinyl ether are preferable because they are easily copolymerized with other monomers and easily available industrially. These vinyl monomers (a4) can be used alone or in combination of two or more.

  Further, as the vinyl monomer (a4), as a monomer having a fluorine atom other than the fluoroolefin compound (a1), 2,2,3,3-tetrafluoropropyl vinyl ether, 2,2,3,3 , 4, 4, 5, 5-octafluoropentyl vinyl ether, perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, perfluoropropyl vinyl ether, perfluorooctyl vinyl ether, perfluorocyclohexyl vinyl ether, and other fluoroalkyl vinyl ether compounds may be used. I do not care.

  In order to produce the fluororesin aqueous dispersion (A), first, the fluorocopolymer (A ′) is produced. Examples of the method for producing the fluorine copolymer (A ′) include the following two methods.

(Manufacturing method 1)
[First step]
The monomer mixture (I) essentially comprising the fluoroolefin compound (a1), the vinyl monomer (a2) having a hydroxyl group, and the vinyl monomer (a3) having a carboxyl group is copolymerized.
[Second step]
To the reaction product obtained in the first step, the monomer mixture (II) having the fluoroolefin compound (a1) and the vinyl monomer (a2) having a hydroxyl group as essential components is added, and further copolymerized.

(Manufacturing method 2)
[First step]
The monomer mixture (II) essentially comprising the fluoroolefin compound (a1) and the vinyl monomer (a2) having a hydroxyl group is copolymerized.
[Second step]
In the reaction product obtained in the first step, a monomer mixture in which the fluoroolefin compound (a1), the vinyl monomer (a2) having a hydroxyl group, and the vinyl monomer (a3) having a carboxyl group are essential ( I) is added and the copolymerization is further carried out.

  In addition, in said manufacturing method 1 and manufacturing method 2, even if monomer mixture (I) or monomer mixture (II) used at the 1st process and the 2nd process is charged at once, it is charged in multiple times. It doesn't matter.

  The monomer mixture (I) essentially comprises the fluoroolefin compound (a1), a vinyl monomer (a2) having a hydroxyl group, and a vinyl monomer (a3) having a carboxyl group. The monomer (a4) may be contained in the monomer mixture.

  The amount of each monomer used in the monomer mixture (I) is good in weather resistance and chemical resistance, and when used as an aqueous fluorine paint, compatibility with other paint components is good. Therefore, the total of the vinyl monomers (a2), (a3) and (a4) is preferably in the range of 0.6 to 1.5 mol with respect to 1 mol of the fluoroolefin compound (a1). The range of 8-1.2 mol is more preferable, and the range of 0.9-1.1 mol is more preferable. The molar ratio of the vinyl monomer (a2) in the total of the vinyl monomers (a2), (a3) and (a4) is preferably in the range of 10 to 97 mol%, and 15 to 60 mol%. Is more preferable, and the range of 20 to 50 mol% is more preferable. Furthermore, the molar ratio of the vinyl monomer (a3) in the total of the vinyl monomers (a2), (a3) and (a4) is preferably in the range of 3 to 60 mol%, and 5 to 50 mol%. Is more preferable, and the range of 8 to 40 mol% is more preferable.

  The monomer mixture (II) essentially comprises the fluoroolefin compound (a1) and a vinyl monomer (a2) having a hydroxyl group, but the vinyl monomer (a4) is a single monomer. It may be contained in the body mixture.

  The amount of each monomer used in the monomer mixture (II) is compatible with other paint components when used as an aqueous fluorine paint, and the weather resistance and chemical resistance of the paint film are good. Therefore, the total amount of the vinyl monomers (a2) and (a4) is preferably in the range of 0.6 to 1.5 mol with respect to 1 mol of the fluoroolefin compound (a1), 0.8 The range of -1.2 mol is more preferable, and the range of 0.9-1.1 mol is more preferable. The molar ratio of the vinyl monomer (a2) in the total of the vinyl monomers (a2) and (a4) is preferably in the range of 10 to 100 mol%, more preferably in the range of 15 to 60 mol%. The range of 20 to 50 mol% is more preferable. The monomer mixture (II) may contain a vinyl monomer (a3) having a carboxyl group, but the molar ratio in the monomer mixture (II) is 2 mol. % Or less, more preferably 1.5 mol% or less, still more preferably 1 mol% or less.

  In the monomer mixture (I), the total molar ratio of the vinyl monomers (a2) and (a3) in the total of the vinyl monomers (a2), (a3) and (a4) is 100. In the case of less than mol%, and in the monomer mixture (II), the molar ratio of the vinyl monomer (a2) in the total of the vinyl monomers (a2) and (a4) is less than 100 mol%. In this case, the balance is the vinyl monomer (a4).

  Examples of the polymerization initiator used in the copolymerization reaction performed in the above production methods 1 and 2 include azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile; t-butyl peroxypivalate, t-butyl. Peroxybenzoate, t-butylperoxy-2-ethylhexanoate, benzoyl peroxide, lauroyl peroxide, acetyl peroxide, di-t-butyl peroxide, dicumyl peroxide, t-butyl hydroperoxide, cumene Examples thereof include peroxides such as hydroperoxide, methyl ethyl ketone peroxide, and diisopropyl peroxycarbonate. These polymerization initiators can be used alone or in combination of two or more.

  The amount of the polymerization initiator used can be appropriately determined according to the type of polymerization initiator, the polymerization temperature, the molecular weight of the copolymer, etc., but the total amount of monomers to be copolymerized is 100 parts by mass. The range of 0.01 to 10 parts by mass is preferable.

  In the copolymerization reaction performed in the above production methods 1 and 2, as required, lauryl mercaptan, 2-mercaptoethanol, thioglycerol, ethylthioglycolic acid, octylthioglycolic acid, etc. The chain transfer agent may be used.

  Further, the copolymerization reaction is preferably performed in an organic solvent. Various organic solvents can be used as long as they do not inhibit the copolymerization reaction. However, in order to obtain the fluororesin aqueous dispersion (A), it is preferable to mainly use an organic solvent miscible with water. . Examples of water-miscible organic solvents include alkyl alcohols such as methanol, ethanol, n-propanol, isopropanol, t-butanol and 3-methoxy-1-butanol; 2,2,2-trifluoroethanol, 2- Fluoroalcohols such as fluoroethanol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-propyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol n-propyl ether, propylene glycol n -Glycol ethers such as butyl ether, diethylene glycol dimethyl ether and dipropylene glycol dimethyl ether Diethylene glycol monomethyl ether acetate, glycol ether esters such as diethylene glycol monoethyl ether acetate; dioxane, acetone, methyl ethyl ketone, dimethylformamide, diacetone alcohol, and tetrahydrofuran.

  Among the above organic solvents, when a low boiling point solvent such as acetone, methyl ethyl ketone, or isopropanol, or a solvent that can be azeotroped with water such as butanol or butyl cellosolve is used as a reaction solvent or a dispersion aid, these organic solvents are usually used. It can be easily distilled off under pressure or reduced pressure, and a fluororesin aqueous dispersion with a reduced content of organic solvent can be obtained.

  Moreover, although the reaction temperature in said copolymerization reaction can be performed in the reaction temperature range of normal radical polymerization, the range of 0-150 degreeC is preferable and the range of 40-100 degreeC is more preferable. As reaction time, the range of 1-50 hours is preferable, and the range of 3-30 hours is more preferable.

  The acid value of the fluorocopolymer (A ′) obtained in the second step of the above production methods 1 and 2 has good water dispersibility, high storage stability, and coating when used as an aqueous fluorine paint. Since the water resistance of the film is also good, the range of 5 to 40 is preferable, and the range of 10 to 35 is more preferable.

  When the aqueous fluororesin composition of the present invention is used in an aqueous fluorocoating compounded with the curing agent (C) described later, the coating film of the coating has excellent mechanical strength, and thus the above production method The hydroxyl value of the fluorine copolymer (A ′) obtained in the second step of 1 and 2 is preferably in the range of 20 to 200, more preferably in the range of 30 to 150, and still more preferably in the range of 30 to 120. In addition, the hydroxyl group which a fluorine copolymer (A ') has reacts with the hardening | curing agent (C) mentioned later, and becomes a crosslinking point.

  In addition, the weight average molecular weight (Mw) of the fluorine copolymer (A ′) obtained in the second step of the production methods 1 and 2 has good water dispersibility, high storage stability, and aqueous fluorine. The range of 5,000 to 100,000 is preferable, the range of 10,000 to 60,000 is more preferable, and the range of 12,000 to 40,000 is preferable because the mechanical strength of the coating film when used as a paint is also good. The range of is more preferable. Here, the weight average molecular weight (Mw) is a value converted to polystyrene based on gel permeation chromatography (hereinafter abbreviated as “GPC”) measurement. The measurement conditions for GPC are as follows.

[GPC measurement conditions]
Measuring device: High-speed GPC device (“HLC-8220GPC” manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSKgel G4000" (7.8 mm ID x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 “TSKgel G2000” (7.8 mm ID × 30 cm) × 1 detector: RI (differential refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection amount: 100 μL (tetrahydrofuran solution with a sample concentration of 4 mg / mL)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

(Standard polystyrene)
"TSKgel standard polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-550" manufactured by Tosoh Corporation

  Examples of the basic compound used for neutralizing the carboxyl group in the third step of the production methods 1 and 2 include ammonia; alkylamines such as trimethylamine, triethylamine, and butylamine; dimethylaminoethanol, diethanolamine, aminomethylpropanol, and the like. Examples include amino alcohols; polyvalent amines such as ethylenediamine and diethylenetriamine; morpholine. Among these, dimethylaminoethanol is preferable because it is miscible with water and an organic solvent and is volatile and hardly remains in the coating film. These basic compounds can be used alone or in combination of two or more.

  The aqueous medium in which the resin neutralized with the basic compound of the fluorine copolymer (A ′) is dispersed is preferably one containing water as a main component and at least 50% by mass of water. Examples of those that can be used as an aqueous medium together with water include alkyl alcohols such as methanol, ethanol, n-propanol, isopropanol, t-butanol, 3-methoxy-1-butanol, and diacetone alcohol; ethylene glycol monomethyl ether, Ethylene glycol monoethyl ether, ethylene glycol mono n-propyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol n-propyl ether, propylene glycol n-butyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, etc. Glycol ether; diethylene glycol monomethyl ether Le acetate, diethylene glycol ether esters such as monoethyl ether acetate; dioxane, acetone, methyl ethyl ketone, dimethylformamide, tetrahydrofuran, and the like. Moreover, these aqueous media can be used alone or in combination of two or more.

  Next, the organic solvent (B) having a hydroxyl group will be described. The organic solvent (B) is not particularly limited as long as it has a hydroxyl group from the viewpoint of improving the storage stability of the aqueous fluororesin composition of the present invention. For example, methanol, ethanol, n- Aliphatic alcohols such as propanol, isopropanol, n-butanol, isobutanol, s-butanol, t-butanol, 3-methoxy-1-butanol, 1-hexanol, cyclohexanol, diacetone alcohol; ethylene glycol monomethyl ether, ethylene glycol Monoethyl ether, ethylene glycol mono n-propyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol Mono n- propyl ether, glycol monomethyl ether and propylene glycol mono-n- butyl ether, ethylene glycol, propylene glycol, and polyhydric alcohols such as glycerin. Among these, since the storage stability of the aqueous fluororesin composition of the present invention is further improved, an aliphatic alcohol or glycol monoether having a solubility in water at 20 ° C. of 5% by mass or more is preferable, and 20 ° C. An aliphatic alcohol or glycol monoether having a solubility in water of 20% by mass or more is more preferable. These solvents can be used alone or in combination of two or more.

  Moreover, as the usage-amount of the said organic solvent (B), from a viewpoint of storage stability improvement, the hydroxyl group (OHB) in the said organic solvent (B) and the hydroxyl group (OHA ') in the said fluorine copolymer (A') are used. The equivalent ratio (OHB / OHA ′) to 0.2) is 0.2 or more, preferably 0.3 or more, and more preferably 0.5 or more.

  The aqueous fluororesin composition of the present invention contains the fluororesin aqueous dispersion (A) and the organic solvent (B). As a method for obtaining the aqueous fluororesin composition, for example, the fluororesin aqueous dispersion The production method (P) in which the organic solvent (B) is previously contained in the fluororesin aqueous dispersion (A) during the production of the body (A), and the fluororesin after the fluororesin aqueous dispersion (A) is produced. Examples include a production method (Q) in which the aqueous dispersion (A) and the solvent (B) are mixed, or a production method using these in combination.

  Furthermore, as the production method (P), a method (P1) in which the organic solvent (B) is used as a polymerization solvent for the fluorine copolymer (A ′) in the fluororesin aqueous dispersion (A), A method of obtaining the fluororesin aqueous dispersion (A) by adding the organic solvent (B) to the fluorocopolymer (A ′) obtained by polymerization and then dispersing them in an aqueous medium (P2 ), The method (P3) using the organic solvent (B) as an aqueous medium in obtaining the fluororesin aqueous dispersion (A) from the fluorocopolymer (A ′) obtained by polymerization, or these The manufacturing method etc. which used these together.

  The water-based fluorine paint of the present invention contains the above-mentioned water-based fluorine resin composition and a curing agent (C) having a functional group that reacts with a hydroxyl group or a carboxyl group. The curing agent (C) can be used as a water-based paint together with the fluororesin aqueous dispersion of the present invention, and can be used as long as it has a functional group that reacts with the hydroxyl group or carboxyl group of the fluororesin aqueous dispersion. . Among the curing agents (C), examples of the compound having a functional group that reacts with a hydroxyl group include a polyisocyanate compound, a block polyisocyanate compound, a polyepoxy compound, a polycyclocarbonate compound, an amino resin, a polycarboxyl compound, and a polyhydroxy compound. A compound, a polyoxazoline compound, a polycarbodiimide compound, etc. are mentioned. Among these, when drying at room temperature such as on-site construction, a water-dispersible polyisocyanate compound, that is, a water-dispersible polyisocyanate (C1) is preferable because of its ease of use and excellent coating film properties.

  Examples of the water-dispersible polyisocyanate (C1) include (1) a mixture of a hydrophobic polyisocyanate and a polyisocyanate having a hydrophilic group, and (2) a hydrophilic group having no hydrophobic polyisocyanate and an isocyanate group. And (3) polyisocyanate having a hydrophilic group, and the like. In the present invention, the hydrophilic group means an anionic group, a cationic group or a nonionic group.

  Examples of the hydrophobic polyisocyanate include those having no hydrophilic group such as an anionic group, a cationic group, and a nonionic group in the molecule. For example, 1,4-tetramethylene diisocyanate, ethyl (2, 6-diisocyanato) hexanoate, 1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate and other aliphatic diisocyanates Aliphatic triisocyanates such as 1,3,6-hexamethylene triisocyanate, 1,8-diisocyanate-4-isocyanatomethyloctane, 2-isocyanatoethyl (2,6-diisocyanate) hexanoate; , 3-Bis (isocyaner Methylcyclohexane), 1,4-bis (isocyanatomethylcyclohexane), 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane, 3,5,5-trimethyl (3-isocyanatomethyl) cyclohexyl isocyanate , Dicyclohexylmethane-4,4′-diisocyanate, 2,5-diisocyanatomethylnorbornane, alicyclic diisocyanate such as 2,6-diisocyanatomethylnorbornane; 2,5-diisocyanatomethyl-2-iso Cycloaliphatic triisocyanates such as cynate propyl norbornane and 2,6-diisocyanatomethyl-2-isocyanate propyl norbornane; m-xylylene diisocyanate, α, α, α ′, α′-tetramethyl-m- Xylylene diisocyanate Aralkylene diisocyanate such as m-phenylene diisocyanate, p-phenylene diisocyanate, tolylene-2,4-diisocyanate, 2,6-diisocyanate, diphenylmethane-4,4′-diisocyanate, naphthalene-1,5-diisocyanate, diphenyl-4 Aromatic diisocyanates such as 4,4'-diisocyanate, 4,4'-diisocyanate-3,3'-dimethyldiphenyl, 3-methyl-diphenylmethane-4,4'-diisocyanate, diphenyl ether-4,4'-diisocyanate; Aromatic triisocyanates such as triphenylmethane triisocyanate and tris (isocyanatophenyl) thiophosphate; A polyisocyanate having a uretdione structure obtained by cyclizing and dimerizing a diisocyanate; a polyisocyanate having an isocyanurate structure obtained by cyclizing and trimerizing the isocyanate groups of the various diisocyanates or triisocyanates described above; Or a polyisocyanate having a burette structure obtained by reacting triisocyanate with water; a polyisocyanate having an oxadiazine trione structure obtained by reacting various diisocyanates or triisocyanates with carbon dioxide; having an allophanate structure Polyisocyanate etc. are mentioned.

  Examples of the polyisocyanate having a hydrophilic group include polyethers, polyesters, polyurethanes, vinyl polymers, alkyd resins, fluororesins, and silicon resins having a hydrophilic group and an isocyanate group. Among these, a polyether or vinyl polymer having a hydrophilic group and an isocyanate group is preferable because of good water dispersibility. These polyisocyanates having a hydrophilic group can be used alone or in combination of two or more.

  Examples of the dispersant having no isocyanate group but having a hydrophilic group include, for example, an acrylic polymer, a fluoroolefin polymer, a vinyl ester polymer, and an aromatic vinyl having no isocyanate group but having a hydrophilic group. Examples thereof include a polymer and a polyolefin polymer.

  The curing agent (C) can be used alone or in combination of two or more. It is also possible to use a combination of a functional group that reacts with a hydroxyl group and a functional group that reacts with a carboxyl group. It is.

  When the water-dispersible polyisocyanate (C1) is used as the curing agent (C), a coating film having good mechanical strength can be obtained, and the amount used is an isocyanate group possessed by the water-dispersible polyisocyanate. The range in which the equivalent ratio (NCO / OHA ′) between (NCO) and the hydroxyl group (OHA ′) of the fluorine copolymer (A ′) in the aqueous fluororesin composition is 0.5 to 5 is preferably 0. The range which becomes 0.7-3 is more preferable, and the range which becomes 1-2 is more preferable.

  The aqueous fluorine paint of the present invention includes inorganic pigments, organic pigments, extender pigments, dyes, waxes, surfactants, stabilizers, flow regulators, antifoaming agents, leveling agents, rheology control agents, ultraviolet rays as necessary. Various additives such as an absorbent, a light stabilizer, an antioxidant, and a plasticizer can be blended.

  In addition, the water-based fluorine paint of the present invention includes, for example, metals such as iron, nickel, aluminum, copper, and lead; alloys containing these metals; Various surface-treated metals that have been plated or chemically treated; thermoplastic resins such as polystyrene, polymethyl methacrylate, ABS resin, polyphenylene oxide, polyurethane, polyethylene, polyvinyl chloride, polypropylene, polybutylene terephthalate, and polyethylene terephthalate; unsaturated Examples thereof include thermosetting resins such as polyester resins, phenol resins, and crosslinked polyurethanes; molded articles such as the above metals and resins; and construction members such as concrete, slate, tile, tile, glass, and wooden building materials.

  Furthermore, the coating film of the aqueous fluorine paint of the present invention is particularly excellent in chemical stability and has a long coating film life, so that it can be used in harsh environments such as roof substrates and chemical factory buildings, It can be suitably used as a material for protecting building articles such as high-rise building outer walls and large bridges that are difficult to repaint.

  In addition, the water-based fluorine paint of the present invention can be coated with a thick film in applications requiring a long-term protection function such as heavy anticorrosion coating, and a coating film thickness of 40 μm or more after drying is formed. You can also

  Next, the present invention will be specifically described with reference to examples and comparative examples. In addition, the acid value of a polymer is measured based on JIS test method K0070-1992. The number average molecular weight (Mn) and the weight average molecular weight (Mw) are measured under the following GPC measurement conditions. Moreover, the methanol residual amount in a polymer solution is measured on the following gas chromatograph (GC) measurement conditions. The solubility of each solvent in water is based on the solvent pocket book (Ohm) and LANG'S HANDBOOK OF CHEMISTRY.

[GC measurement conditions]
Measuring device: Gas chromatograph ("GC-2010" manufactured by Shimadzu Corporation)
Column: “DB-WAXETR” manufactured by Agilent Technologies
Inner diameter 0.25mm, film thickness 0.25mm, column length 30m
Detector: FID
Quantitative method: Internal standard method using cyclohexanone

[GPC measurement conditions]
Measuring device: High-speed GPC device (“HLC-8220GPC” manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSKgel G4000" (7.8 mm ID x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 “TSKgel G2000” (7.8 mm ID × 30 cm) × 1 detector: RI (differential refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection amount: 100 μL (tetrahydrofuran solution with a sample concentration of 4 mg / mL)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

(Standard polystyrene)
"TSKgel standard polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-550" manufactured by Tosoh Corporation

(Example 1: Production of aqueous fluororesin composition (1))
[First step]
In a stainless steel autoclave substituted with nitrogen inside, 100.7 parts by mass of diethylene glycol dimethyl ether (hereinafter abbreviated as “MDM”), 127.1 parts by mass of methanol (hereinafter abbreviated as “MeOH”), ethyl Vinyl ether (hereinafter abbreviated as “EVE”) 38.5 parts by mass, 4-hydroxybutyl vinyl ether (hereinafter abbreviated as “HBVE”) 27.5 parts by mass, cyclohexyl vinyl ether (hereinafter abbreviated as “CHVE”) 2.8 parts by mass, light stabilizer (“TINUVIN 292” manufactured by BASF Japan Ltd., bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and methyl (1,2,2) , 6,6-pentamethyl-4-piperidinyl) sebacate; hereinafter abbreviated as “HALS”. 16.5 parts by weight, and were charged t- butyl peroxypivalate 4.0 part by weight as a polymerization initiator. Next, 96.3 parts by mass of liquefied chlorotrifluoroethylene (hereinafter abbreviated as “CTFE”) was injected into the autoclave, and then the autoclave was heated to 63 ° C. Subsequently, while maintaining the temperature at 63 ° C., 288.7 parts by mass of liquefied CTFE was injected over the course of 2.5 hours. Simultaneously with the start of CTFE injection, EVE 115.5 parts by mass, HBVE 82.5 parts by mass, CHVE 8.2 parts by mass, MDM 59.4 parts by mass, MeOH 59.4 parts by mass, and t-butyl peroxypivalate 11.8 parts by mass The mixture consisting of was pressed over 2.5 hours.

[Second step]
After completion of the injection of the monomer in the first step, 214.5 parts by mass of liquefied CTFE was continuously injected into the autoclave over 1.5 hours. Further, EVE 55.0 parts by mass, HBVE 55.0 parts by mass, CHVE 5.5 parts by mass, 10-undecenoic acid (hereinafter abbreviated as “UDA”) 110.0 parts by mass, MDM 52.8 parts by mass, MeOH 52.8. A mixture consisting of 1 part by mass and 10.6 parts by mass of t-butyl peroxypivalate as a polymerization initiator was injected over 2.5 hours. After the press-fitting, 26.4 parts by mass of MDM was press-fitted for washing the press-fitting line. The autoclave was kept at 63 ° C. and reacted for 12 hours from the start of CTFE injection in the first step. Then, the internal pressure of the autoclave was returned to normal pressure, and 1,579 parts by mass of the reaction product was recovered. The obtained solution was put into a 3 liter four-necked flask, 78 parts by mass of an inorganic synthetic adsorbent (“Kyoward 500 (G7)” manufactured by Kyowa Chemical Industry Co., Ltd.) was added, and the mixture was stirred at 60 ° C. for 4 hours. Subsequently, filtration was performed, and the filtrate was distilled off under reduced pressure to obtain an 82.1% by mass solution of a fluorine copolymer (A′-1). The residual amount of methanol in this solution was 0.11% by mass. The fluorine copolymer (A′-1) had an acid value of 25.7 mgKOH / g, a number average molecular weight (Mn) of 6,700, and a weight average molecular weight (Mw) of 20,100. It was.

[Third step]
2 liters of 500 parts by mass of the fluorocopolymer (A′-1) solution obtained in the second step and 47.3 parts by mass of 3-methoxy-1-butanol (hereinafter abbreviated as “MB”) Into a four-necked flask, heated to 40 ° C., 16.3 parts by weight of dimethylethanolamine (hereinafter abbreviated as “DMEA”) was added, and the mixture was stirred and homogenized for 1 hour. The temperature was raised and 457.5 parts by mass of ion-exchanged water was gradually added while stirring to obtain a non-volatile content of 39.8% by mass, a viscosity of 608 mPa · s (25 ° C., B-type viscometer (rotation speed 60 rpm, rotor # 3 )) Aqueous fluororesin composition (1) was obtained.

  About the aqueous | water-based fluororesin composition (1) obtained above, the storage stability, the gel fraction of the coating film at the time of using for an aqueous | water-based fluorine coating material, and coating-film characteristics (gloss and pencil hardness) were evaluated.

<Evaluation of storage stability>
The aqueous fluororesin composition (1) was put in a 200 mL glass bottle, stored in a thermostatic bath at 40 ° C. in a sealed state, and the state after 3 months was evaluated.
(Appearance) Visually evaluated.
○: Generation of precipitate and no gelation ×: Precipitation generation or gelation (viscosity) Viscosity was measured and evaluated by the rate of change in viscosity before and after storage.
“Viscosity change rate” = | “Viscosity after storage” − “Initial viscosity” | / “Initial viscosity”
Viscosity measurement conditions: 25 ° C., B-type viscometer (rotation speed 60 rpm, rotor # 3)
◎: Viscosity change rate is less than 100% ○: Viscosity change rate is 100% or more and less than 200% △: Viscosity change rate is 200% or more ×: Cannot be measured due to gelation −: Unmeasured due to precipitation (molecular weight) Molecular weight Was measured and evaluated by the molecular weight change rate before and after storage.
“Molecular weight change rate” = | “weight average molecular weight after storage” − “initial weight average molecular weight” | / “initial weight average molecular weight”
○: Molecular weight change rate of less than 25% ×: Molecular weight change rate of 25% or more

<Preparation of water-based fluorine paint and preparation of coating film>
Aqueous fluororesin composition (1) 75.4 parts by mass (30 parts by mass as a fluororesin), 70 parts by mass of titanium oxide (“Taipaque CR-97” manufactured by Ishihara Sangyo Co., Ltd.), and 21.3 parts by mass of ion-exchanged water Were mixed to obtain a pigment mixture. The pigment mixture had a PWC (percentage of the pigment mass with respect to the solid mass) of 70% by mass and a non-volatile content of 60% by mass. This pigment mixture was dispersed using a batch mill to obtain a pigment dispersion. With respect to 100 parts by mass of this pigment dispersion, 113.1 parts by mass of the aqueous fluororesin composition (1), 0.6 parts by mass of a surfactant (“BYK-348” manufactured by BYK Japan KK), an antifoaming agent ("SN deformer 777" manufactured by San Nopco Co., Ltd.) After adding 0.2 parts by mass and 48.6 parts by mass of ion-exchanged water, the mixture is uniformly mixed to obtain a paint base having a PWC of 40% by mass and a nonvolatile content of 40% by mass Got. Next, 11.6 parts by mass of a curing agent (“Bernock DNW-5500” manufactured by DIC Corporation, water-dispersible polyisocyanate, non-volatile content 80% by mass) is added to 100 parts by mass of the paint main component, and then mixed uniformly. As a result, an aqueous fluorine paint (1) was obtained. The equivalent ratio [(NCO) / (OH)] of the isocyanate group (NCO) to the hydroxyl group (OH) in the aqueous fluororesin composition (1) was 1.2. DNW-5500 was mixed immediately before coating.

  The water-based fluorine paint (1) obtained above is applied to a polypropylene plate and a zinc phosphate-treated steel plate (JIS G3141 (SPCC-SD) PB-44 manufactured by Nippon Test Panel Co., Ltd.), and a 6 mil (152 μm) applicator. After coating, the film was dried in a thermostatic chamber at 23 ° C. for 7 days to prepare a coating film having a thickness of about 40 μm.

<Measurement of gel fraction>
The coating film was peeled off from the polypropylene plate and weighed, and then immersed in acetone for 24 hours. After the coating film remaining without being dissolved in acetone was dried at 108 ° C. for 2 hours, the percentage obtained by dividing the mass by the mass before being immersed in acetone was defined as the gel fraction.

<Measurement of glossiness of coating film>
About the coating film obtained above, using a gloss meter (“Gloss meter GM-26D” manufactured by Murakami Color Research Laboratory), 60 ° glossiness and 20 ° glossiness were each measured at 5 points. The average value was taken as the measured value.

<Measurement of pencil hardness of coating film>
About the coating film obtained above, based on JIS test method K5600-5-4: 1999, pencil hardness was measured using "Uni" by Mitsubishi Pencil Co., Ltd. for the pencil.

(Example 2: Production of aqueous fluororesin composition (2))
[First step]
In an autoclave made of stainless steel with the inside replaced with nitrogen, MDM 100.7 parts by mass, MeOH 127.1 parts by mass, EVE 20.7 parts by mass, HBVE 20.7 parts by mass, CHVE 2.1 parts by mass, UDA 41.3 parts by mass, HALS 16. 5 parts by mass and 4.0 parts by mass of t-butyl peroxypivalate as a polymerization initiator were charged. Next, 80.5 parts by mass of liquefied CTFE was injected into the autoclave, and then the autoclave was heated to 63 ° C. Subsequently, 134.0 parts by mass of liquefied CTFE was injected over 1.5 hours while maintaining the temperature at 63 ° C. Simultaneously with the start of CTFE injection, EVE 34.3 parts by mass, HBVE 34.3 parts by mass, CHVE 3.4 parts by mass, UDA 68.7 parts by mass, MDM 33.0 parts by mass, MeOH 33.0 parts by mass, and t-butyl peroxypi A mixture consisting of 6.6 parts by mass of barate was injected over 1.5 hours.

[Second step]
After completion of the monomer injection in the first step, 385.0 parts by mass of liquefied CTFE was continuously injected into the autoclave over 2.5 hours. In addition, a mixture comprising 154.0 parts by mass of EVE, 110.0 parts by mass of HBVE, 11.0 parts by mass of CHVE, 79.2 parts by mass of MDM, 79.2 parts by mass of MeOH, and 15.8 parts by mass of t-butyl peroxypivalate was obtained. Press-fit over 5 hours. After the press-fitting, 26.4 parts by mass of MDM was press-fitted for washing the press-fitting line. The autoclave was kept at 63 ° C. and reacted for 12 hours from the start of CTFE injection in the first step. Then, the internal pressure of the autoclave was returned to normal pressure, and 1,538 parts by mass of the reaction product was recovered. The obtained solution was put into a 3 liter four-necked flask, 78 parts by mass of an inorganic synthetic adsorbent (“Kyoward 500 (G7)” manufactured by Kyowa Chemical Industry Co., Ltd.) was added, and the mixture was stirred at 60 ° C. for 4 hours. Subsequently, filtration was performed, and the filtrate was distilled off under reduced pressure to obtain an 82.2% by mass solution of a fluorine copolymer (A′-2). The residual amount of methanol in this solution was 0.09% by mass. The fluorine copolymer (A′-2) had an acid value of 25.9 mgKOH / g, a number average molecular weight (Mn) of 6,200, and a weight average molecular weight (Mw) of 22,000. It was.

[Third step]
500 parts by mass of the fluorocopolymer solution obtained in the second step and 48 parts by mass of MB are put into a 2 liter four-necked flask, heated to 40 ° C., and 16.5 parts by mass of dimethylethanolamine is added. After stirring for a period of time to homogenize, the temperature was raised to 60 ° C., and 457.9 parts by mass of ion-exchanged water was gradually added while stirring to obtain a non-volatile content of 39.6% by mass and a viscosity of 695 mPa · s (25 ° C., An aqueous fluororesin composition (2) of a B-type viscometer (rotation speed: 60 rpm, rotor # 3) was obtained.

  With respect to the aqueous fluororesin composition (2) obtained above, the storage stability was evaluated by the same operation as in Example 1. Further, using the aqueous fluororesin composition (2) in an amount of 30 parts by mass as the fluororesin, an aqueous fluorocoating paint (2) was prepared by the same operation as in Example 1, and the obtained aqueous fluorocoating paint ( The gel fraction and coating film characteristics (gloss and pencil hardness) of the coating film of 2) were evaluated.

(Example 3: Production of aqueous fluororesin composition (3))
[First step]
In an autoclave made of stainless steel, the inside of which was replaced with nitrogen, MDM 247.1 parts by mass, MeOH 311.9 parts by mass, EVE 70.9 parts by mass, HBVE 50.7 parts by mass, CHVE 5.1 parts by mass, UDA 65.9 parts by mass, HALS 40. 5 parts by mass and 9.8 parts by mass of t-butyl peroxypivalate as a polymerization initiator were charged. Next, 212.7 parts by mass of liquefied CTFE was injected into the autoclave, and then the autoclave was heated to 63 ° C. Subsequently, with the temperature kept at 63 ° C., 354.3 parts by mass of liquefied CTFE was injected over 1.5 hours. Simultaneously with the start of CTFE injection, EVE 118.1 parts by mass, HBVE 84.3 parts by mass, CHVE 8.4 parts by mass, UDA 109.6 parts by mass, MDM 81.0 parts by mass, MeOH 81.0 parts by mass, and t-butyl peroxypi A mixture consisting of 16.2 parts by mass of barate was injected over 1.5 hours.

[Second step]
After completion of the monomer injection in the first step, 1.51.5 parts by mass of liquefied CTFE 931.5 was continuously injected into the autoclave over 2.5 hours. In addition, a mixture composed of 391.5 parts by mass of EVE, 270.0 parts by mass of HBVE, 27.0 parts by mass of CHVE, 194.4 parts by mass of MDM, 194.4 parts by mass of MeOH, and 38.9 parts by mass of t-butyl peroxypivalate was used. Press-fit over 5 hours. After completion of the press-fitting, 64.8 parts by mass of MDM was press-fitted for washing the press-fitting line. The autoclave was kept at 63 ° C. and reacted for 12 hours from the start of CTFE injection in the first step. Then, the internal pressure of the autoclave was returned to normal pressure, and 3,844 parts by mass of the reaction product was recovered. The obtained solution was put into a 5-liter four-necked flask, 190 parts by mass of an inorganic synthetic adsorbent (“Kyoward 500 (G7)” manufactured by Kyowa Chemical Industry Co., Ltd.) was added, and the mixture was stirred at 60 ° C. for 4 hours. Subsequently, filtration was performed, and the filtrate was distilled off under reduced pressure to obtain an 82.8% by mass solution of a fluorine copolymer (A′-3). The residual amount of methanol in this solution was 0.10% by mass. The fluorine copolymer (A′-3) had an acid value of 17.2 mg KOH / g, a number average molecular weight (Mn) of 6,800, and a weight average molecular weight (Mw) of 22,000. It was.

[Third step]
500 parts by mass of the fluorocopolymer solution obtained in the second step and 52 parts by mass of MB are put into a 2 liter four-necked flask, heated to 40 ° C., and 10.9 parts by mass of dimethylethanolamine is added. After stirring for a period of time to homogenize, the temperature was raised to 60 ° C., and 457.9 parts by mass of ion-exchanged water was gradually added while stirring to obtain a non-volatile content of 39.6% by mass and a viscosity of 253 mPa · s (25 ° C., An aqueous fluororesin composition (3) of a B-type viscometer (rotation speed: 60 rpm, rotor # 3) was obtained.

  With respect to the aqueous fluororesin composition (3) obtained above, storage stability was evaluated in the same manner as in Example 1. Moreover, by using the aqueous fluororesin composition (3) in an amount of 30 parts by mass as the fluororesin, an aqueous fluorocoating material (3) was prepared by the same operation as in Example 1, and the obtained aqueous fluorocoating material ( The gel fraction and coating properties (gloss and pencil hardness) of the coating film of 3) were evaluated.

(Example 4: Production of aqueous fluororesin composition (4))
500 parts by mass of the fluorocopolymer (A′-3) obtained in the second step of Example 3, 23 parts by mass of MDM, and 29 parts by mass of isopropanol (hereinafter abbreviated as “IPA”) are 2 liters of 4 parts. After putting in a one-necked flask and heating to 40 ° C., 10.9 parts by mass of dimethylethanolamine was added, and the mixture was stirred for 1 hour to make it uniform, then heated to 60 ° C. and ion-exchanged water 466. 9 parts by mass was gradually added to obtain an aqueous fluororesin composition (4) having a nonvolatile content of 39.7% by mass and a viscosity of 476 mPa · s (25 ° C., B-type viscometer (rotation speed: 60 rpm, rotor # 3)). It was.

  The storage stability of the aqueous fluororesin composition (4) obtained above was evaluated by the same operation as in Example 1. In addition, using the aqueous fluororesin composition (4) in an amount of 30 parts by mass as the fluororesin, an aqueous fluorocoating paint (4) was prepared by the same operation as in Example 1, and the obtained aqueous fluorocoating paint ( The gel fraction and coating properties (gloss and pencil hardness) of the coating film of 4) were evaluated.

(Example 5: Production of aqueous fluororesin composition (5))
500 parts by mass of the fluorocopolymer (A′-3) obtained in the second step of Example 3, 16 parts by mass of MDM, and 36 parts by mass of t-butanol (hereinafter abbreviated as “t-BuOH”). Place in a 2 liter four-necked flask, heat to 40 ° C, add 10.9 parts by mass of dimethylethanolamine, stir for 1 hour to homogenize, raise the temperature to 60 ° C, and stir 466.9 parts by mass of exchange water was gradually added to form an aqueous fluororesin composition having a nonvolatile content of 39.9% by mass and a viscosity of 650 mPa · s (25 ° C., B-type viscometer (rotation speed 60 rpm, rotor # 3)). 5) was obtained.

About the aqueous | water-based fluororesin composition (5) obtained above, the storage stability was evaluated by operation similar to Example 1. FIG. Further, by using the aqueous fluororesin composition (5) in an amount of 30 parts by mass as the fluororesin, an aqueous fluorocoating material (5) was prepared by the same operation as in Example 1, and the obtained aqueous fluorocoating material ( The gel fraction and the coating properties (gloss and pencil hardness) of the coating of 5) were evaluated.
(Example 6: Production of aqueous fluororesin composition (6))
[First step]
In a stainless steel autoclave substituted with nitrogen inside, MB 196.4 parts by mass, methyl ethyl ketone 31.4 parts by mass, EVE 28.9 parts by mass, HBVE 20.7 parts by mass, CHVE 2.1 parts by mass, UDA 26.9 parts by mass, HALS 16 .5 parts by mass, and 4.0 parts by mass of t-butyl peroxypivalate as a polymerization initiator were charged. Next, 86.7 parts by mass of liquefied CTFE was injected into the autoclave, and then the autoclave was heated to 63 ° C. Subsequently, with the temperature maintained at 63 ° C., 144.3 parts by mass of liquefied CTFE was injected over 1.5 hours. Simultaneously with the start of CTFE injection, EVE 48.1 parts by mass, HBVE 34.3 parts by mass, CHVE 3.4 parts by mass, UDA 44.6 parts by mass, MDM 33.0 parts by mass, methyl ethyl ketone 33.0 parts by mass, and t-butylperoxy A mixture consisting of 6.6 parts by mass of pivalate was injected over 1.5 hours.

[Second step]
After the completion of the monomer injection in the first step, 379.5 parts by mass of liquefied CTFE was continuously injected into the autoclave over 2.5 hours. Further, a mixture comprising 159.5 parts by mass of EVE, 110.0 parts by mass of HBVE, 11.0 parts by mass of CHVE, 79.2 parts by mass of MB, 79.2 parts by mass of methyl ethyl ketone, and 15.8 parts by mass of t-butyl peroxypivalate 3 Press-fit over 5 hours. After completion of the press-fitting, 26.4 parts by mass of MB was press-fitted for washing the press-fitting line. The autoclave was kept at 63 ° C. and reacted for 12 hours from the start of CTFE injection in the first step. Then, the internal pressure of the autoclave was returned to normal pressure, and 1,566 parts by mass of the reaction product was recovered. The obtained solution was put into a 3 liter four-necked flask, 78 parts by mass of an inorganic synthetic adsorbent (“Kyoward 500 (G7)” manufactured by Kyowa Chemical Industry Co., Ltd.) was added, and the mixture was stirred at 60 ° C. for 4 hours. Subsequently, filtration was performed, and the filtrate was distilled off under reduced pressure to obtain a 75.8% by mass solution of a fluorine copolymer (A′-4). The acid value of this fluorocopolymer (A′-4) was 15.6 mgKOH / g, the number average molecular weight (Mn) was 6,000, and the weight average molecular weight (Mw) was 19,900.

[Third step]
500 parts by mass of the fluorocopolymer solution obtained in the second step and 5.3 parts by mass of MB are placed in a 2-liter four-necked flask, heated to 40 ° C., and then added with 9.9 parts by mass of dimethylethanolamine. After stirring for 1 hour to make it uniform, the temperature was raised to 60 ° C., and 457.9 parts by mass of ion-exchanged water was gradually added while stirring to obtain a non-volatile content of 39.5% by mass and a viscosity of 378 mPa · s (25 An aqueous fluororesin composition (6) having a B-type viscometer (rotation speed: 60 rpm, rotor # 3)) was obtained.

  About the aqueous | water-based fluororesin composition (6) obtained above, the storage stability was evaluated by operation similar to Example 1. FIG. Further, by using the aqueous fluororesin composition (6) in an amount of 30 parts by mass as the fluororesin, an aqueous fluorocoating composition (6) was prepared by the same operation as in Example 1, and the obtained aqueous fluorocoating composition ( The gel fraction and coating film characteristics (gloss and pencil hardness) of the coating film of 6) were evaluated.

(Example 7: Production of aqueous fluororesin composition (7))
500 parts by mass of the fluorocopolymer (A′-3) obtained in the second step of Example 3 and 52.0 parts by mass of MB were placed in a 2 liter four-necked flask, heated to 40 ° C., and then dimethylethanol. Add 10.9 parts by weight of amine and stir for 1 hour to homogenize, then heat to 60 ° C., gradually add 466.9 parts by weight of ion-exchanged water and 155.0 parts by weight of MeOH while stirring, An aqueous fluororesin composition (7) having a nonvolatile content of 35.0% by mass and a viscosity of 129 mPa · s (25 ° C., B-type viscometer (rotation speed: 60 rpm, rotor # 3)) was obtained.

  The storage stability of the aqueous fluororesin composition (7) obtained above was evaluated by the same operation as in Example 1. Further, using the aqueous fluororesin composition (7) in an amount of 30 parts by mass as the fluororesin, an aqueous fluorocoating material (7) was prepared by the same operation as in Example 1, and the obtained aqueous fluorocoating material ( The gel fraction and the coating properties (gloss and pencil hardness) of the coating film of 7) were evaluated. The non-volatile content of the pigment mixture and the paint main agent was adjusted by reducing the amount of ion-exchanged water added during production.

(Example 8: Production of aqueous fluororesin composition (8))
500 parts by mass of the fluorocopolymer (A′-3) obtained in the second step of Example 3 and 52 parts by mass of propylene glycol n-butyl ether (hereinafter abbreviated as “PNB”) After putting in a one-necked flask and heating to 40 ° C., 10.9 parts by mass of dimethylethanolamine was added, and the mixture was stirred and homogenized for 1 hour, then heated to 60 ° C. and ion-exchanged water 540 mass with stirring. The aqueous fluororesin composition (8) having a nonvolatile content of 37.3 mass% and a viscosity of 573 mPa · s (25 ° C., B-type viscometer (rotation speed: 60 rpm, rotor # 3)) was obtained.

  With respect to the aqueous fluororesin composition (8) obtained above, storage stability was evaluated by the same operation as in Example 1. Further, using the aqueous fluororesin composition (8) in an amount of 30 parts by mass as the fluororesin, an aqueous fluorocoating paint (8) was prepared by the same operation as in Example 1, and the obtained aqueous fluorocoating paint ( The gel fraction and the coating properties (gloss and pencil hardness) of the coating film of 8) were evaluated.

(Example 9: Production of aqueous fluororesin composition (9))
500 parts by mass of the fluorocopolymer (A′-3) obtained in the second step of Example 3, 30 parts by mass of MDM, and 22 parts by mass of MB were placed in a 2 liter four-necked flask and heated to 40 ° C. After adding 10.9 parts by mass of dimethylethanolamine, the mixture was stirred and homogenized for 1 hour, heated to 60 ° C., 466.9 parts by mass of ion-exchanged water was gradually added while stirring, and a non-volatile content of 40 A water-based fluororesin composition (9) having a viscosity of 4.0% by mass and a viscosity of 412 mPa · s (25 ° C., B-type viscometer (rotation speed: 60 rpm, rotor # 3)) was obtained.

  With respect to the aqueous fluororesin composition (9) obtained above, storage stability was evaluated by the same operation as in Example 1. In addition, by using the aqueous fluororesin composition (9) in an amount of 30 parts by mass as the fluororesin, an aqueous fluorocoating material (9) was prepared by the same operation as in Example 1, and the obtained aqueous fluorocoating material ( The gel fraction and coating properties (gloss and pencil hardness) of the coating film of 9) were evaluated.

(Comparative Example 1: Production of aqueous fluororesin composition (R1))
500 parts by mass of the fluorocopolymer (A′-1) obtained in the second step of Example 1 and 47.3 parts by mass of MDM were placed in a 2-liter four-necked flask and heated to 40 ° C. After adding 16.3 parts by mass of ethanolamine and stirring for 1 hour to make it uniform, the temperature was raised to 60 ° C., and 457.5 parts by mass of ion-exchanged water was gradually added while stirring to obtain a non-volatile content of 39.6. An aqueous fluororesin composition (R1) having a mass% and a viscosity of 850 mPa · s (25 ° C., B-type viscometer (rotation speed: 60 rpm, rotor # 3)) was obtained.

  The storage stability of the aqueous fluororesin composition (R1) obtained above was evaluated by the same operation as in Example 1. In addition, using the aqueous fluororesin composition (R1) in an amount of 30 parts by mass as the fluororesin, an aqueous fluorocoating material (R1) was prepared by the same operation as in Example 1, and the obtained aqueous fluorocoating material ( The gel fraction and coating properties (gloss and pencil hardness) of the coating of R1) were evaluated.

(Comparative Example 2: Production of aqueous fluororesin composition (R2))
500 parts by mass of the fluorocopolymer (A′-2) obtained in the second step of Example 2 and 48 parts by mass of MDM were placed in a 2 liter four-necked flask, heated to 40 ° C., and then dimethylethanolamine. After adding 16.5 parts by mass and stirring for 1 hour to make uniform, the temperature was raised to 60 ° C., and 457.9 parts by mass of ion-exchanged water was gradually added while stirring to obtain a nonvolatile content of 40.1% by mass. An aqueous fluororesin composition (R2) having a viscosity of 778 mPa · s (25 ° C., B-type viscometer (rotation speed: 60 rpm, rotor # 3)) was obtained.

  With respect to the aqueous fluororesin composition (R2) obtained above, the storage stability was evaluated by the same operation as in Example 1. Further, by using the aqueous fluororesin composition (R2) in an amount of 30 parts by mass as the fluororesin, an aqueous fluorocoating material (R2) was prepared by the same operation as in Example 1, and the obtained aqueous fluorocoating material ( The gel fraction and coating properties (gloss and pencil hardness) of the coating of R2) were evaluated.

(Comparative Example 3: Production of aqueous fluororesin composition (R3))
500 parts by mass of the fluorocopolymer (A′-3) obtained in the second step of Example 3 and 52 parts by mass of MDM were placed in a 2-liter four-necked flask, heated to 40 ° C., and then dimethylethanolamine. After adding 10.9 parts by mass and stirring for 1 hour to make uniform, the temperature was raised to 60 ° C., 466.9 parts by mass of ion-exchanged water was gradually added while stirring, and the non-volatile content was 39.8% by mass. An aqueous fluororesin composition (R3) having a viscosity of 608 mPa · s (25 ° C., B-type viscometer (rotation speed: 60 rpm, rotor # 3)) was obtained.

  The storage stability of the aqueous fluororesin composition (R3) obtained above was evaluated in the same manner as in Example 1. In addition, using the aqueous fluororesin composition (R3) in an amount of 30 parts by mass as the fluororesin, an aqueous fluorocoating paint (R3) was prepared by the same operation as in Example 1, and the obtained aqueous fluorocoating paint ( The gel fraction and coating properties (gloss and pencil hardness) of the coating of R3) were evaluated.

  Table 1 shows the composition, acid value, number average molecular weight, and weight average molecular weight of the monomers of the fluorine copolymers produced in Examples 1 to 8 and Comparative Examples 1 to 3. Tables 2 and 3 show the composition of the aqueous fluororesin composition and the storage stability evaluation results, and the coating film evaluation results of the aqueous fluorine paint.

The solubility of the organic solvent (B) in water at 20 ° C. in Tables 2 and 3 is as follows (based on Solvent Pocket Book (Ohm), LANG'S HANDBOOK OF CHEMISTRY).
MeOH: Infinite MB: Infinite IPA: Infinite t-BuOH: Infinite PNB: 6.4% by mass

  In Tables 2 and 3, MeOH described in Examples 1 to 5, Examples 8 to 9 and Comparative Examples 1 to 3 is the residual MeOH after distillation under reduced pressure in the second step during the production of the aqueous resin composition. It comes from.

  From the evaluation results of Examples 1 to 9 shown in Table 2 and Table 3, the fluororesin composition of the present invention has very excellent storage stability, and aqueous fluorine using the fluororesin composition The coating film properties of the paint were also good.

  Comparative Examples 1 to 3 shown in Table 3 are equivalent ratios (OHB / OHA ′) of the hydroxyl group (OHB) in the organic solvent (B) and the hydroxyl group (OHA ′) in the fluorine copolymer (A ′). However, although it was an example of less than 0.2, it was found that the coating properties of the aqueous fluorine paint using the fluororesin composition were relatively good, but poor in storage stability.

Claims (9)

An aqueous fluororesin composition comprising an aqueous fluororesin dispersion (A) and an organic solvent (B) having a hydroxyl group,
Monomer mixture (I) in which the fluororesin aqueous dispersion (A) is essentially composed of a fluoroolefin compound (a1), a vinyl monomer (a2) having a hydroxyl group, and a vinyl monomer (a3) having a carboxyl group. The monomer mixture (II) in which the fluoroolefin compound (a1) and the vinyl monomer having a hydroxyl group (a2) are essential to the reaction product obtained in the first step and the first step of copolymerization reaction) In addition, the second step of further copolymerizing to obtain the fluorine copolymer (A ′), neutralizing the carboxyl group of the fluorine copolymer (A ′) with a basic compound, in an aqueous medium It was obtained through the third step of dispersing in
The equivalent ratio (OHB / OHA ′) of the hydroxyl group (OHB) in the organic solvent (B) and the hydroxyl group (OHA ′) in the fluorine copolymer (A ′) is 0.2 or more. An aqueous fluororesin composition. An aqueous fluororesin composition comprising an aqueous fluororesin dispersion (A) and an organic solvent (B) having a hydroxyl group,
A first step in which the fluororesin aqueous dispersion (A) is copolymerized with a monomer mixture (II) essentially comprising a fluoroolefin compound (a1) and a vinyl monomer (a2) having a hydroxyl group, To the reaction product obtained in the step, a monomer mixture (I) essentially comprising a fluoroolefin compound (a1), a vinyl monomer having a hydroxyl group (a2) and a vinyl monomer having a carboxyl group (a3) In addition, the second step of further copolymerizing to obtain the fluorine copolymer (A ′), neutralizing the carboxyl group of the fluorine copolymer (A ′) with a basic compound, in an aqueous medium Obtained through the third step of dispersing in
The equivalent ratio (OHB / OHA ′) of the hydroxyl group (OHB) in the organic solvent (B) and the hydroxyl group (OHA ′) in the fluorine copolymer (A ′) is 0.2 or more. An aqueous fluororesin composition.   The monomer mixture (I) or (II) includes the vinyl monomer (a4) other than the fluoroolefin compound (a1), the vinyl monomer (a2), and the vinyl monomer (a3). The aqueous fluororesin composition according to claim 1 or 2.   The amount of each monomer used in the monomer mixture (I) is the sum of the vinyl monomers (a2), (a3) and (a4) with respect to 1 mol of the fluoroolefin compound (a1). The molar ratio of the vinyl monomer (a2) in the total of the vinyl monomers (a2), (a3) and (a4) is 10 to 1.5 mol. The molar ratio of the vinyl monomer (a3) in the total of the vinyl monomers (a2), (a3) and (a4) is in the range of 3 to 60 mol%. The amount of each monomer used in the monomer mixture (II) is 0 in total of the vinyl monomers (a2) and (a4) with respect to 1 mol of the fluoroolefin compound (a1). The vinyl in the total of the vinyl monomers (a2) and (a4) 3. The aqueous fluororesin composition according molar ratio is in the range of 10 to 100 mole percent of mer (a2).   The aqueous fluororesin composition according to claims 1 to 4, wherein the vinyl monomer (a3) is a monomer having 4 or more atoms between a carboxyl group and a vinyl group.   The aqueous fluororesin composition according to claim 1, wherein the organic solvent (B) has a solubility in water at 20 ° C. of 5% by mass or more.   An aqueous fluororesin composition comprising the aqueous fluororesin composition according to any one of claims 1 to 6 and a curing agent (C) having a functional group that reacts with a hydroxyl group or a carboxyl group.   The water-based fluorine paint according to claim 7, wherein the curing agent (C) is a water-dispersible polyisocyanate (C1).   An article coated with the water-based fluorine paint according to claim 7 or 8.