JPH07268163A - Aqueous fluororesin composition - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an aqueous fluororesin composition which is excellent in warm water resistance and solvent resistance of the resulting coating film while maintaining the weather resistance which is an excellent property of the aqueous fluororesin composition. provide. The aqueous fluororesin composition contains a fluoropolymer and an acrylic polymer, and the acrylic polymer is
An aqueous dispersion of composite polymer particles in which 0.1 to 20 parts by weight of a carbonyl group-containing monomer is copolymerized with 100 parts by weight of the acrylic polymer, and 1 mol of the carbonyl group of the acrylic polymer. On the other hand, it contains a hydrazine derivative having at least two hydrazino groups, which is blended in a ratio of 0.02 to 1 mol.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous fluororesin composition, and more particularly to an aqueous fluororesin composition capable of forming a coating film having excellent weather resistance, warm water resistance and solvent resistance.

[0002]

2. Description of the Related Art Fluororesin-based water-based coating materials have excellent weather resistance and do not need to be reapplied for a long period of time. They are also excellent in heat resistance, gas impermeability, electrical insulation, and the like. In recent years, development has been advanced as a solution coating material that does not require the use of a large amount of solvent unlike a solution coating material in which a resin is dissolved and which meets social demands such as environmental protection, resource saving, and safety.

However, the fluororesin-based water-based coating material generally has the drawbacks of low processability (especially film-forming property) and adhesion to the substrate.
Many attempts have been made to modify a fluororesin polymer with an acrylic polymer. For example, JP-A-62-32102
Japanese Patent Laid-Open Publication No. 3-78784 discloses an aqueous dispersion obtained by emulsion-polymerizing an ethylenically unsaturated monomer in the presence of fluororesin-based polymer particles. Aqueous dispersions obtained by emulsion polymerization of acrylic acid esters and / or methacrylic acid esters in the presence of the same have been proposed.

However, in an experiment conducted by the present inventors using a conventional fluororesin-based aqueous dispersion, whitening of the coating film, deterioration of gloss, swelling, etc. occur when exposed to natural rainfall in the summer. Was observed, and it was found that the hot water resistance and moisture resistance of the coating film were not sufficient. Further, since the conventional fluororesin-based aqueous dispersion is a non-crosslinking type, its solvent resistance is insufficient.

As a cross-linking type aqueous dispersion, an aqueous dispersion of an acrylic polymer utilizing the cross-linking of a hydrazine derivative and a carbonyl group in a copolymer is disclosed in Japanese Patent Laid-Open No.
Japanese Patent Application Laid-Open No. 144432, Japanese Patent Application Laid-Open No. 57-3850 and Japanese Patent Application Laid-Open No. 57-3857,
When these are formed into a coating film, the hot water resistance and the solvent resistance are improved, but the long-term weather resistance is insufficient.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and its object is to maintain excellent performances of the aqueous fluororesin composition such as weather resistance, and An object is to provide an aqueous fluororesin composition having excellent hot water resistance and solvent resistance.

[0007]

In order to achieve the above object, an aqueous fluororesin composition according to the present invention contains a fluorine-containing polymer and an acrylic polymer, and the acrylic polymer is the acrylic polymer. 0.1 to 20 parts by weight of a carbonyl group-containing monomer is copolymerized with 100 parts by weight of the polymer, and an aqueous dispersion of composite polymer particles, and 1 mol of the carbonyl group of the acrylic polymer, And a hydrazine derivative having at least two hydrazino groups, which is blended in a proportion of 0.02 to 1 mol.

The above-mentioned fluorine-containing polymer is preferably a vinylidene fluoride homopolymer obtained by emulsion polymerization or a copolymer of vinylidene fluoride and another fluoroolefin, particularly preferably vinylidene fluoride / hexafluoropropylene. The copolymer is a vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer. These fluoropolymers are used alone or in admixture of two or more.

As the monomer component of the acrylic polymer,
Acrylic acid alkyl ester and / or methacrylic acid alkyl ester whose alkyl group has 1 to 18 carbon atoms 40 to 99.1% by weight, carbonyl group-containing vinyl monomer 0.1 to 20% by weight, ethylenically unsaturated monoester 0-3
0% by weight, other copolymerizable vinyl monomer 0-59.9
It is preferably in the weight%.

An aqueous dispersion of composite polymer particles of a fluorine-containing polymer and an acrylic polymer contains 2 parts of the vinyl monomer in 100 parts by weight of the fluorine-containing polymer in an aqueous medium.
It is preferable that 0 to 500 parts by weight are polymerized.

An aqueous dispersion of composite polymer particles containing a fluorine-containing polymer and an acrylic polymer in the present invention is
Usually, it is produced by emulsion-polymerizing an acrylic polymer monomer in an aqueous medium in the presence of fluorine-containing polymer particles.

Generally, a fluoroolefin is used as the fluorine-containing polymer and a monomer of the acrylic polymer is used.
C1-18 alkyl acrylate and /
Alternatively, a methacrylic acid alkyl ester, a carbonyl group-containing vinyl monomer, and if necessary, an ethylenically unsaturated carboxylic acid, and a vinyl monomer copolymerizable with the above monomer are used.

The structure of the composite polymer particles is a copolymer type of a fluoroolefin and a monomer, a core / shell type in which a fluorine-containing polymer is a core, and an acrylic polymer is a shell, or the opposite substance. Examples of the core-shell type include a homogeneous type in which a fluorine-containing polymer and an acrylic polymer are uniformly compatible in a single particle, and the homogeneous type is preferable particularly when importance is attached to weather resistance. .

This is easily achieved by showing a single glass transition point in differential scanning calorimetry, or by forming an optically transparent film when the composite polymer particles are formed into a film. Can be distinguished.

As the fluorine-containing polymer, a vinylidene fluoride polymer is preferably used.

The vinylidene fluoride polymer is a vinylidene fluoride homopolymer or vinylidene fluoride and a monomer copolymerizable therewith, such as vinyl fluoride, tetrafluoroethylene, trifluorochloroethylene,
Hexafluoropropylene, hexafluoroisobutylene, perfluoroacrylic acid or its alkyl ester, perfluoromethacrylic acid or its alkyl ester, fluorine-containing ethylenically unsaturated compounds such as fluoroalkyl ester of acrylic acid or methacrylic acid, propylene cyclohexyl vinyl ether, hydroxy It is selected from copolymers with non-fluorine-containing ethylenically unsaturated compounds such as ethyl vinyl ether, and non-fluorine-containing diene compounds such as butadiene, isoprene and chloroprene.

In the case of a vinylidene fluoride copolymer, a copolymer having a vinylidene fluoride content of 50% by weight or more is usually used. In the present invention, vinylidene fluoride homopolymer, vinylidene fluoride which is a binary copolymer /
Tetrafluoroethylene copolymer, vinylidene fluoride /
A hexafluoropropylene copolymer, a terpolymer such as vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer, and the like are preferably used. Among these, vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer The combination and vinylidene fluoride / hexafluoropropylene copolymer are particularly preferably used. These vinylidene fluoride polymers are used alone or in combination of two or more.

The composition ratio of the above copolymer is preferably 50 to 90% by weight of vinylidene fluoride and 50 to 10% by weight of tetrafluoroethylene in the vinylidene fluoride / tetrafluoroethylene copolymer. In the vinylidene fluoride / hexafluoropropylene copolymer, vinylidene fluoride is preferably 50 to 90% by weight,
Hexafluoropropylene is 50 to 10% by weight,
In the vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer, vinylidene fluoride is preferably 50 to 80% by weight, tetrafluoroethylene is 10 to 40% by weight, and hexafluoropropylene is 5 to 40% by weight. .

The weight average molecular weight of the vinylidene fluoride polymer is usually 1 to 200,000.

The vinylidene fluoride polymer can be obtained by various methods such as emulsion polymerization, solution polymerization and precipitation polymerization.
In the present invention, a vinylidene fluoride polymer obtained by emulsion polymerization is particularly preferably used.

The vinylidene fluoride polymer needs to be dispersed as particles in an aqueous medium at the stage of emulsion polymerizing the acrylic copolymer monomer. It is not limited.

As a method for dispersing a vinylidene fluoride polymer in an aqueous medium, for example, (i) emulsion polymerization of vinylidene fluoride in an aqueous medium in the presence or absence of a copolymerizable monomer is carried out. Method, (ii) phase inversion of a vinylidene fluoride polymer solution into an aqueous dispersion, (iii) precipitation polymerization of vinylidene fluoride in the presence or absence of a copolymerizable monomer, and Examples include a method of dispersing coalesced particles in an aqueous medium. Among these methods, the emulsion polymerization method (i) is preferable since the aqueous dispersion of vinylidene fluoride polymer particles can be used as it is for the emulsion polymerization of the next acrylic polymer.

The average particle size of the vinylidene fluoride polymer particles varies depending on the desired average particle size of the aqueous dispersion of polymer particles, but it is usually in the range of 0.03 to 0.3 μm. The thickness is preferably 0.03 to 0.2 μm.

As the acrylic polymer monomer,
(A) C1 to C18 alkyl acid alkyl ester and / or methacrylic acid alkyl ester, (b) carbonyl group-containing vinyl monomer, and (c) if necessary.
Examples thereof include ethylenically unsaturated carboxylic acid and (d) vinyl monomers copolymerizable with the above monomers.

Monomer (a): The number of carbon atoms of the alkyl group is 1 to
Examples of the acrylate alkyl ester which is 18 include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, hexyl acrylate, cyclohexyl acrylate. , 2-ethylhexyl acrylate, lauryl acrylate, and the like. Of these, alkyl acrylates having an alkyl group with 4 to 12 carbon atoms are preferable, and n-butyl acrylate and isobutyl acrylate 2-ethylhexyl acrylate are particularly preferable. These monomers may be used alone or in admixture of two or more.

The alkyl group has 1 to 18 carbon atoms.
Examples of the methacrylic acid alkyl ester are methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-Ethylhexyl methacrylate, lauryl methacrylate, etc. can be mentioned. Of these, alkyl methacrylates having an alkyl group having 1 to 6 carbon atoms are preferable, and methyl methacrylate and cyclohexyl methacrylate are particularly preferable. These monomers are used alone or in combination of two or more.

In the present invention, when the acrylic acid alkyl ester and the methacrylic acid alkyl ester are used in combination, the ratio of the two is not particularly limited, but the vinylidene fluoride polymer particles contain a carbonyl group. In order to make the acrylic polymer uniformly compatible with each other, it is preferable to use 50% by weight or more of the alkyl methacrylic acid ester with respect to 100 parts by weight of the total amount of the monomer (a).

When the aqueous fluororesin composition of the present invention is used as a coating agent for room temperature drying, the amount of the alkyl acrylate ester used is 30 parts by weight per 100 parts by weight of the total amount of the monomer (a). It is preferably ˜50% by weight. If it is less than 30% by weight, the film-forming property at low temperature drying is deteriorated, and if it is more than 50% by weight, the weather resistance is deteriorated.

Monomer (b): As the carbonyl group-containing monomer, a monomer having at least one aldo group or keto group and one polymerizable double bond in the molecule is used. . That is, the carbonyl group-containing monomer is particularly a polymerizable monoolefinically unsaturated aldo compound and keto compound, and excludes compounds having only an ester group (-COC-) and a carboxyl group (-COOH). .

Carbonyl group-containing monomers are, in particular, acrolein, diacetone acrylamide, formyl styrene, preferably vinyl alkyl ketones having 4 to 7 carbon atoms, such as especially vinyl methyl ketone, vinyl ethyl ketone and vinyl. Examples thereof include those represented by the following general formula (Formula 1) such as isobutyl ketone.

[Chemical 1] Wherein R ¹ is —H or —CH ₃ ; R ² is —H or an alkyl group having 1 to 3 carbon atoms; R ³ is 1
An alkyl group having 3 to 3 carbon atoms; R ⁴ represents an alkyl group having 1 to 4 carbon atoms. In particular,
(Meth) cryloxyalkyl propanal, acetonitrile acrylate, diacetone acrylate, diacetone methacrylate, 2-hydroxypropyl acrylate-acetylacetate and butanediol-
1,4-acrylate-acetyl acetate and the like can be mentioned. Among these, diacetone acrylamide acrolein and vinyl methyl ketone are preferable.

Monomer (C): Examples of the ethylenically unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, maleic anhydride, crotonic acid, etc., and particularly acrylic. Acid and itaconic acid are preferred. These monomers may be used alone or in admixture of two or more.

Monomer (d): The above-mentioned monomers (a) to (c)
Other monomers that can be copolymerized with are acrylamide,
Methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N, N
-Amide compounds such as dialkylacrylamide, N, N-dialkylmethacrylamide, 2-hydroxyethyl acrylate, acrylic acid esters such as 2-hydroxyethyl acrylate, N, N-dialkylaminoethyl acrylate, glycidyl acrylate, fluoroalkyl acrylate, methacrylic acid 2 -Hydroxyethyl, N, N-dialkylaminoethyl methacrylate, glycidyl methacrylate, fluoroalkyl methacrylate, methacrylic acid esters such as ethylene glycol dimethacrylate, vinyl ether compounds such as allyl glycidyl ether, 1,3-butadiene, isoprene,
Conjugated dienes such as chloroprene, aromatic vinyl compounds such as styrene, α-methylenestyrene, halogenated styrene and divinylbenzene, silicon-containing ethylenic compounds such as vinyltrimethoxysilane, vinyltriethoxysilane and γ-methacryloxypropyltriethoxysilane Examples thereof include unsaturated monomers and fluorine-containing ethylenic unsaturated monomers such as fluoroalkyl esters of acrylic acid or methacrylic acid. Among these, N-methyl acrylamide, N-methyl methacrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, allyl glycidyl ether, 1,3-butadiene and styrene are preferable. These monomers may be used alone or in admixture of two or more.

The composition of the monomers (a) to (d) is such that the monomer (a) is preferably 40 to 99.9% by weight, more preferably 50 to 80% by weight. ) Is preferably 0.1 to 20% by weight, more preferably 2 to 7% by weight, the monomer (c) is preferably 0 to 30% by weight, more preferably 1 to 15% by weight, and a single amount. The body is
Preferably 0 to 59.9% by weight, more preferably 0 to
It is 30% by weight.

Particularly, the amount of the carbonyl group-containing monomer (b) used is 0.1% by weight based on the total amount of the monomers (a) to (d).
If it is less than 20% by weight, sufficient hot water resistance and solvent resistance cannot be obtained, and if it exceeds 20% by weight, weather resistance and hot water resistance may deteriorate, which is not preferable.

The aqueous dispersion of the composite polymer particles of the present invention comprises
In the presence of 100 parts by weight of the fluorine-containing polymer particles, a monomer mixture 20 to 50 composed of the monomers (a) to (d).
It is obtained by emulsion polymerization of 0 parts by weight, more preferably 40 to 300 parts by weight, in an aqueous medium.

If the amount of the monomer mixture of the monomers (a) to (d) used is less than 20 parts by weight, the processability (especially the film forming property) and the adhesion to the substrate will be reduced, and If it exceeds 500 parts by weight, the weather resistance and chemical resistance of the vinylidene fluoride polymer itself are impaired.

Emulsion polymerization of the monomer mixture in the presence of the fluorine-containing polymer particles in the present invention can be considered as one kind of seed polymerization. Although the reaction behavior is not always clear, it is considered that the added monomer is mainly absorbed or adsorbed in the fluorine-containing polymer particles, and the polymerization proceeds while swelling the particles.

The conditions of this emulsion polymerization are not particularly limited, and for example, the reaction is carried out in an aqueous medium in the presence of an emulsifier and a polymerization initiator at a temperature of about 30 to 100 ° C. for about 1 to 30 hours. If necessary, a chain transfer agent, a chelating agent, a pH adjusting agent, a solvent and the like may be added.

As the emulsifier, an anionic surfactant, a nonionic surfactant, a combination of an anionic surfactant and a nonionic surfactant, and the like are used. In some cases, an amphoteric surfactant, Cationic surfactants can also be used.

Examples of the anionic surfactant include higher alcohol sulfuric acid ester sodium salt, alkylbenzene sulfonic acid sodium salt, succinic acid dialkyl ester sulfonic acid sodium salt, alkyl diphenyl ether disulfonic acid sodium salt, polyoxyethylene alkyl ether sulfuric acid sodium salt. , Polyoxyethylene alkylphenyl ether sulfate sodium salt and the like. Of these, sodium lauryl sulfate ester, sodium dodecylbenzene sulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkylphenyl ether sulfate and the like are preferable.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkylaryl ether, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester and the like. Generally, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether and the like are used.

Examples of the amphoteric surfactant include lauryl betaine, hydroxyethyl imidazoline sulfate sodium salt, imidazoline sulfonic acid sodium salt and the like.

Examples of the cationic surfactant include alkylpyridinium chloride, alkyltrimethylammonium chloride, dialkyldimethylammonium chloride, alkyldimethylbenzylammonium chloride and the like.

Further, in the present invention, as the emulsifier, a fluorine-based surface active agent such as perfluoroalkylcarboxylic acid salt, perfluoroalkylsulfonic acid salt, perfluoroalkylphosphoric acid ester, perfluoroalkylpolyoxyethylene, perfluoroalkylbetaine, etc. Agents can also be used.

Further, in the emulsion polymerization of the present invention, a so-called reactive emulsifier which is copolymerizable with the monomers (a) to (d), for example, styrene sulfonic acid sodium salt,
Allyl alkyl sulfonic acid sodium salt, polyoxyethylene alkyl allyl phenyl ether sulfate ammonium salt, polyoxyethylene alkyl allyl phenyl ether, etc. can be used, especially 2- (1-allyl)
A combination of -4-nonylphenoxy polyethylene glycol sulfate ammonium salt and 2- (1-allyl) -4-nonylphenoxy polyethylene glycol is preferred.

The amount of the emulsifier used is usually about 0.05 to 5 parts by weight per 100 parts by weight of the total amount of the vinylidene fluoride polymer particles and the monomers (a) to (d).

As the polymerization initiator, it is possible to use a water-soluble polymerization initiator such as potassium persulfate, ammonium persulfate, hydrogen peroxide, or a redox system in which these water-soluble polymerization initiator and a reducing agent are combined. it can. Examples of the reducing agent include sodium pyrobisulfite, sodium hydrogen sulfite, sodium sulfite, sodium thiosulfate, L-ascorbic acid or a salt thereof, sodium formaldehyde sulfoxylate, ferrous sulfate and glucose.

An oil-soluble polymerization initiator can also be used by dissolving it in a monomer or a solvent. Examples of the oil-soluble polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis- (4-methoxy-2,
4-dimethylvaleronitrile), 2,2'-azobis-
2,4-Dimethylvaleronitrile, 1,1′-azobiscyclohexane-1-carbonitrile, 2,2′-azobisisovaleronitrile, 2,2′-azobisisocapronitrile, 2,2′- Azobis (phenylisobutyronitrile), benzoyl peroxide, di-t-butyl peroxide, dilauroyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramenthane hydroperoxide, t-
Butyl hydroperoxide, 3,5,5-trimethylhexanol peroxide, t-butyl peroxy (2
-Ethyl hexanoate) and the like. Preferred oil-soluble polymerization initiators are 2,2'-azobisisobutyronitrile, benzoyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramenthane hydroperoxide, t-butyl hydroperoxide, 3,2. 5,5-trimethylhexanol peroxide, t-butylperoxy (2-
Ethyl hexanoate) and the like.

The amount of the polymerization initiator used is usually about 0.1 to 3 parts by weight based on 100 parts by weight of all the monomers.

Examples of the chain transfer agent include halogenated hydrocarbons (eg, carbon tetrachloride, chloroform, bromoform, etc.), mercaptans (eg, n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, n-hexadecyl). Mercaptan etc.), xanthogens (eg dimethylxanthogen disulfide, diethylxanthogen disulfide, diisopropylxanthogen disulfide etc.), tempenes (eg dipentene, terpinolene etc.), thiuram sulfides (eg tetramethylthiuram monosulfide, tetraethylthiuram disulfide, tetrabutylthiuram) Disulfide, dipentamethylthiuram disulfide, etc.).

The amount of the chain transfer agent used is about 0 to 10 parts by weight based on 100 parts by weight of all the monomers.

Examples of the chelating agent include glycine, alanine, ethylenediaminetetraacetic acid and the like, and examples of the pH adjusting agent include sodium carbonate, potassium carbonate, sodium hydrogen carbonate and ammonia.

The amount of the chelating agent and the pH adjusting agent used is 0 to 0.1 per 100 parts by weight of all the monomers.
It is about 0 to 3 parts by weight.

Examples of the solvent include methyl ethyl ketone, acetone, trichlorotrifluoroethane, methyl isobutyl ketone, dimethyl sulfoxide, toluene, dibutyl phthalate, methylpyrrolidone, ethyl acetate and the like. The amount of solvent used depends on workability,
The amount is preferably a small amount within a range that does not impair disaster prevention safety, environmental safety and manufacturing safety, and is about 0 to 20 parts by weight per 100 parts by weight of all monomers.

When emulsion-polymerizing the monomers (a) to (d) in the presence of fluorine-containing polymer particles in an aqueous medium, the polymer particles and the monomer are added by various methods. can do. As a method of adding them, a method of collectively adding the entire amount of the monomer to the aqueous dispersion of the polymer particles, after charging a part of the monomers to the aqueous dispersion of the polymer particles and reacting them, A method of charging the remaining monomer continuously or in a divided manner, a method of continuously or dividingly adding the total amount of the monomer to the aqueous dispersion of polymer particles, and continuously polymerizing the polymer particles under the polymerization of the monomer. Or a method of adding in a divided manner, etc., in particular, a method of adding the entire amount of the monomer to the aqueous dispersion of polymer particles all at once, or, in the method of initially charging the aqueous dispersion of polymer particles Preferred is a method in which a part of the above monomer is 50% by weight or more of the total amount.

The average particle size of the aqueous dispersion of the composite polymer particles obtained by emulsion-polymerizing the monomers (a) to (d) in the presence of the fluorine-containing polymer particles is:
Usually, it is about 0.06 to 3 μm. A preferable average particle diameter is 0.05 to 0.5 μm, and more preferably, 0.1.
It is from 05 to 0.3 μm. The average particle size is 0.04 μm
When the amount is less than the above, the viscosity of the aqueous dispersion increases, and it is difficult to obtain an aqueous dispersion having a high solid content, and when a large mechanical shearing force is applied depending on the use conditions, coagulation is likely to occur. If one exceeds 1 μm, the storage stability of the aqueous dispersion is slightly lowered. The average particle size of this aqueous dispersion can be adjusted by appropriately selecting the size of the vinylidene fluoride polymer particles.

The aqueous fluororesin composition of the present invention contains an aqueous dispersion of composite polymer particles and a hydrazine derivative.

The hydrazine derivative has at least two hydrazino groups, and is contained in an amount of 0.02 to 1 mol, preferably 0.2 to 0.6 mol, per 1 mol of the carbonyl group contained in the acrylic polymer. Blended in amount.

The compounding amount of the hydrazine derivative is based on 1 mol of the carbonyl group contained in the acrylic polymer.
If the amount is less than 0.02 mol or more than 1 mol, the hot water resistance and solvent resistance of the coating film formed from the aqueous fluororesin composition of the present invention will be insufficient.

In the present invention, examples of the hydrazine derivative having at least two hydrazino groups include oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, isophthalic acid dihydrazide, sebacic acid dihydrazide and malein. Dicarboxylic acid dihydrazides containing 2 to 10, especially 4 to 6 carbon atoms such as acid dihydrazide, fumaric acid dihydrazide and itaconic acid dihydrazide, and ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine And aliphatic water-soluble dihydrazine having 2 to 4 carbon atoms such as butylene-1,4-dihydrazine, and among these, adipic acid dihydrazide, isophthalic acid dihydrazide, sebacic acid dihydrazide Masui.

The hydrazine derivative has the function of reacting the carbonyl group of the copolymer with the hydrazino group in the derivative when water in the aqueous dispersion of the composite polymer particles is scattered by drying to form a film having a network structure. . A catalyst is not usually used for this crosslinking reaction, but in some cases, a catalyst such as a water-soluble metal salt of zinc sulfate, manganese sulfate, cobalt sulfate or the like can be used.

In the aqueous fluororesin composition of the present invention, if necessary, various organic additives may be added in an amount of 40 parts by weight or less based on 100 parts by weight of the solid content of the aqueous dispersion. .

Examples of the additives include silicone antifoaming agents, antifreezing agents such as ethylene glycol and propylene glycol, dyes, organic pigments, dispersants, pH adjusting agents such as ethanolamine, hydroxyethylelcellulose and poly (ethylene glycol). Thickeners such as ether urethane and acrylic acid copolymers, wetting improvers such as butyl cellosolve and ethyl cellosolve, organic fillers, preservatives, antifungal agents, water resistant agents, anti-aging agents, UV absorbers, water-soluble A solvent, a film-forming auxiliary agent, etc. can be mentioned.

If necessary, inorganic compounds such as pigments such as titanium oxide and iron oxide, fillers such as calcium carbonate and aerosil, and the like can be added to the aqueous fluororesin composition of the present invention.

The aqueous fluororesin composition of the present invention is particularly useful as a protective coating material for various substrates.
In that case, after coating on the substrate, it is usually dried at a temperature of about room temperature to 200 ° C.

[0066]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the examples, "parts" and "%" indicating proportions mean parts by weight and% by weight, respectively.

(Example 1) After the inside of a separable flask having a capacity of 7 liters was replaced with nitrogen, vinylidene fluoride polymer A (vinylidene fluoride / tetrafluoroethylene / hexafluoro) was obtained as vinylidene fluoride polymer particles. Propylene copolymer: weight ratio 65/25/10, average particle size 0.15 μm) 100 parts, monomers (a) to (d) shown in Table 1, and 2- (1-allyl) -4 as an emulsifier.
-0.4 parts of nonylphenoxy polyethylene glycol sulfate ammonium salt and 2- (1-allyl)-
1.0 part of 4-nonylphenoxy polyethylene glycol was put in the separable flask and heated to 80 ° C. Then, 1.5 parts of a 2% aqueous solution of potassium persulfate was added as a polymerization initiator, the mixture was polymerized at 85 to 95 ° C. for 3 hours and then cooled to stop the reaction, and pH was adjusted to 8 with ammonia.
Adjusted to. Further, 1.5 parts of adipic acid dihydrazide was added and stirred for about 1 hour to obtain an aqueous fluororesin composition.

FIG. 1 is a transmission electron micrograph showing the structure of the particle cross section of the aqueous fluororesin composition obtained in Example 1. It can be seen that the vinylidene fluoride polymer and the acrylic polymer are uniformly compatible in a single particle.

[Table 1] (Examples 2 and 3) Table 1 as monomers (a) to (d)
An aqueous fluororesin composition was obtained in the same manner as in Example 1 except that the above-mentioned one was used.

Example 4 An aqueous fluororesin composition was prepared in the same manner as in Example 1 except that the monomers shown in Table 1 were used as the monomers (a) to (d) and sebacic acid dihydrazide was used as the crosslinking agent. I got a thing.

Example 5 An aqueous fluororesin composition was obtained in the same manner as in Example 1 except that acrolein was used instead of diacetone acrylamide as the monomer (b).

(Examples 6 to 9) An aqueous fluororesin composition was obtained in the same manner as in Example 1 except that the monomers shown in Table 1 were used as the monomers (a) to (d).

(Example 10) As vinylidene fluoride polymer particles, instead of vinylidene fluoride polymer A,
An aqueous fluororesin composition was prepared in the same manner as in Example 1 except that the vinylidene fluoride polymer B (vinylidene fluoride / tetrafluoroethylene copolymer: weight ratio 68/32, average particle size 0.20 μm) was used. Obtained.

Example 11 As vinylidene fluoride polymer particles, instead of vinylidene fluoride polymer A,
Vinylidene fluoride polymer C (tetrafluoroethylene / hexafluoropropylene copolymer: weight ratio 62/3
Example 8 except that the average particle size was 8, 0.20 μm)
An aqueous fluororesin composition was obtained in the same manner as.

[Table 2] (Comparative Example 1) An aqueous fluororesin composition was obtained in the same manner as in Example 1, except that the monomer (b) was not used.

Comparative Example 2 An aqueous fluororesin composition was obtained in the same manner as in Example 1 except that the hydrazine derivative was not used.

Comparative Example 3 An aqueous fluororesin composition was obtained in the same manner as in Example 1 except that the amount of adipic acid dihydrazide was changed to 30 parts.

(Comparative Example 4) Instead of vinylidene fluoride polymer particles, acrylic polymer particles (average particle size 0.20 μm, weight average molecular weight of 100,000 or more) made of styrene, methyl methacrylate and butyl acrylate were used. An aqueous fluororesin composition was obtained in the same manner as in Example 1 except for the above.

100 parts (in terms of solid part) of the aqueous fluororesin compositions obtained in Examples 1 to 11 and Comparative Examples 1 to 4 as described above, filler 50 parts titanium oxide dispersant polycarboxylic acid sodium salt 2 parts (trade name SN-DIS-PERSANT 5044, manufactured by San Nopco) Antifreeze ethylene glycol 1 part Preservative (product name SN-215, manufactured by San Nopco) 0.05 parts Defoamer (product name FOAMASTER-AP, manufactured by San Nopco) 0.5 parts triethylene glycol dimethyl ether part (trade name DMTG, manufactured by Nippon Emulsifier) was added, and the solid part was adjusted to 60% by weight with water. Then, the viscosity was adjusted using hydroxyethyl cellulose as a thickener. It was adjusted to 4000 cps. Mixing of each of these components was performed using a disper stirrer, and after sufficiently mixing, the mixture was transferred to a vacuum defoaming machine for defoaming to prepare a paint.

The paints obtained as described above were degreased with xylene and an alkaline detergent on an iron plate (JIS-31).
41, SPCC plate, 0.8 × 70 × 1500 mm) using an air spray gun, the coating film thickness after drying is 200
After coating so as to have a thickness of 500 μm or 500 μm (only in the hot water resistance test), it was dried at 80 ° C. for 15 minutes.

The following tests were carried out on these coated iron plates to evaluate each characteristic.

The gloss retention rate (gloss after dipping / gloss before dipping,%) after immersing a hot water- resistant coated iron plate in hot water at 50 ° C. for 1 week was determined, and the degree of swelling of the coating film was visually observed. It was observed and evaluated according to the following criteria.

○: No swelling ×: Large swelling △: Slightly swelling Spotting toluene on the surface of the solvent-resistant coating film, allowing it to stand for 1 hour, and visually observing the appearance of the coating film. It evaluated by the standard of.

[0082] ○ ...... coating no change × ...... coating swelling, dissolution based on weather resistance JIS-K5400, performs a carbon arc lamp type TamotsuSusumu weathering test, the gloss retention after 1000 h (gloss after test / Gloss before test,%) was determined.

The results are shown in Tables 1 and 2.

It can be seen that the coating films formed from the aqueous fluororesin compositions of Examples 1 to 11 are excellent in both hot water resistance and solvent resistance, and have high weather resistance.

Comparative Example 1 is a case in which the monomer (b) which is a carbonyl group-containing monomer is not contained, and the obtained aqueous fluororesin composition is a non-crosslinking type, and the water resistance of the coating film formed is high. It can be seen that the properties and solvent resistance are extremely poor.

Comparative Example 2 is an example containing no hydrazine derivative, and it is understood that the obtained aqueous fluororesin composition is of a non-crosslinked type and the coating film formed is extremely inferior in hot water resistance and solvent resistance. .

Comparative Example 3 is an example in which the content of the hydrazine derivative exceeds the range of the present invention, and the coating film formed from the obtained aqueous fluororesin composition has insufficient hot water resistance and solvent resistance. It is found that the weather resistance is poor.

Comparative Example 4 is an example in which an acrylic copolymer was used in place of the vinylidene fluoride polymer particles, and the weather resistance of the coating film formed from the obtained polymer composition was remarkably poor. I understand.

[0089]

As described above, according to the present invention,
It is possible to provide an aqueous fluororesin composition excellent in hot water resistance and solvent resistance of a coating film obtained while maintaining the weather resistance which is an excellent property of the aqueous fluororesin composition.

The aqueous fluororesin composition of the present invention is extremely useful as a protective coating material for a wide range of substrates such as cement, tiles, metals, plastics and woods, and also for example asbestos, glass, felt and paper. Material for impregnating porous materials, packing material,
It can also be suitably used as a laminate film material, a treating agent for fibers and fabrics, and the like.

[Brief description of drawings]

FIG. 1 is a transmission electron micrograph showing a structure of a particle cross section of an aqueous fluororesin composition according to Example 1.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area C09D 133/12 PGF

Claims (1)

[Claims] 1. A fluorine-containing polymer and an acrylic polymer, wherein the acrylic polymer contains 0.1 parts by weight of a carbonyl group-containing monomer based on 100 parts by weight of the acrylic polymer.
˜20 parts by weight of the copolymerized aqueous dispersion of the composite polymer particles, and 0.
A hydrazine derivative having at least two hydrazino groups, which is blended in a proportion of 02 to 1 mol, and an aqueous fluororesin composition comprising: