JP2910220B2 - Fluororesin aqueous dispersion, method for producing the same, resin composition containing the same, and article coated with the composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fluororesin aqueous dispersion containing a fluoroolefin as an essential component, a production method thereof, and an application thereof.

(Prior Art) Conventionally, the purpose of coating the surface of a metal, an alkaline inorganic cured product such as cement, a plastic or the like is to improve the weather resistance of the substrate,
Not only to improve durability such as chemical resistance and water resistance, but also protection and appearance are taken into consideration.

In recent years, coating agents which are exposed to the outdoors, such as building exterior materials and industrial materials, are required to be maintenance-free and have excellent durability for a long period of time.

The fluoroolefin copolymer is known as a binder having high weather resistance and high chemical resistance, and is commercially available in the form of an organic solvent solution.

However, since it contains a large amount of an organic solvent, there are problems such as fire danger, harm, and air pollution, and an aqueous fluoroolefin-based binder is required.

Conventionally, aqueous dispersions of fluoroolefin polymers such as tetrafluoroethylene, vinylidene fluoride, and hexafluoropropylene have been proposed, but these require baking at a high temperature during the film formation process. Akira
In JP-B-57-38845, in the case of vinylidene fluoride and hexafluoropropylene copolymer, the intrinsic viscosity [η] is
Despite being a low molecular weight copolymer such as 0.1 to 0.5, baking at a temperature of 180 to 230 ° C is required.

Such high-temperature baking is not possible in the field of air-drying paints which are painted on site, and is economically disadvantageous also in factory line painting which basically requires heat drying.

On the other hand, JP-A-61-261367 proposes a coating composition based on an emulsion polymer comprising a fluoroolefin, an alkyl vinyl ether, and a vinyl carboxylate as a method for solving such a problem. Has been greatly improved.

However, the coating agent for objects exposed outdoors is
It is important not only to have durability but also to prevent the appearance from being deteriorated due to contamination of the coating film by soot and the like.

Therefore, film formation is possible at low temperature, and weather resistance, chemical resistance,
At present, there is no water-based coating agent that sufficiently satisfies the durability of the coating film such as water resistance and the stain resistance.

Furthermore, in order to satisfy the high performance requirements for water-based paints in recent years, control of particle size is one of the issues. In the case of acrylic ester-based or olefin-based emulsion polymers containing no fluorine atom, a core / shell polymerization method has been established, and the control thereof has become easier.

In a fluoroolefin-based emulsion polymerization system, an emulsion polymer polymer containing no fluorine atom is conventionally used as a core.

However, in this case, since the affinity between the core and the shell is lacking, a stable core / shell polymer is hardly formed, and control of the particle size cannot be achieved.

(Problems to be Solved by the Invention) It is an object of the present invention to provide a so-called core / polymer in which a monomer mixture having a specific composition is emulsion-polymerized in at least two stages.
An object of the present invention is to provide a fluororesin aqueous dispersion obtained by using a polymer containing a fluorine atom as a core in a shell polymerization method.

(Means for Solving the Problems) In view of the above-described advantages and disadvantages of the related art, the present inventors have conducted intensive studies and as a result, have found that the above problems can be overcome.

That is, the present invention relates to a method for preparing a fluoroalkyl group-containing ethylenic monomer (A) and another copolymerizable monomer (B) by copolymerizing an aqueous resin dispersion (C). A fluororesin aqueous dispersion (E) obtained by emulsion polymerization of a monomer mixture (D) containing an olefin as an essential component, a production method thereof, and an aqueous coating composition using the dispersion as a binder.

The present invention relates to a monomer mixture having a specific composition of at least 2
An aqueous dispersion of a fluororesin prepared according to a so-called core / shell polymerization method in which emulsion polymerization is carried out step by step, particularly, a fluorine atom-containing polymer is used for the core.

First, a method for preparing an aqueous resin dispersion (C) obtained by copolymerizing a first-stage fluoroalkyl group-containing ethylenic monomer (A) as an essential component and other copolymerizable monomers is as follows. It is as follows.

The term “fluoroalkyl group-containing ethylenic monomer (A)” as used herein refers to a straight chain having a polymerizable double bond and having at least one fluorine atom in a side chain portion of the polymer after polymerization. , A branched or cyclic compound having an alkyl group.

Specific examples include vinyl ethers having a fluoroalkyl group, vinyl esters, (meth) acrylates, and the like as typical monomers. For example, trifluoromethyl vinyl ether, 1,1,1-trifluoroethyl vinyl ether, 2,2-difluoroethyl vinyl ether, tetrafluoroethyl vinyl ether, perfluoropropyl vinyl ether, perfluorobutyl vinyl ether, perfluorohexyl vinyl ether, perfluoro Octyl vinyl ether,
3 to 12 carbon atoms such as perfluorododecyl vinyl ether
Vinyl ethers having a perfluoroalkyl group of
And a vinyl ether having a fluoroalkyl group in which a hydrogen atom is partially substituted with fluorine by an alkyl group having 3 to 12 carbon atoms, "Biscoat 8F, 8FM, 3F, 3FM" (a fluorine-containing compound manufactured by Osaka Organic Chemical Co., Ltd. (Meth) acrylic monomers), alcohols having a fluoroalkyl group such as perfluorocyclohexyl (meth) acrylate and esters with methacrylic acid, furthermore, vinyl trifluoroacetate, diperfluorocyclohexyl fumarate, or N -I-propyl perfluorooctanesulfonamidoethyl (meth) acrylate is a typical example.

Other examples of the monomer (B) that can be copolymerized with these include (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, or acids such as citraconic acid, maleic anhydride, and itaconic anhydride. Carboxyl group-containing monomers or dicarboxylic acids such as unsaturated group-containing hydroxyalkyl ester monocarboxylic acids such as adducts of anhydride group-containing monomers and glycols; polycarboxylic acid anhydrides such as maleic anhydride and itaconic anhydride Α, β-ethylenically unsaturated carboxylic acids such as group-containing unsaturated monomers, 2-hydroxyethyl (meth) acrylate, 2-
Hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxy Hydroxyalkyl esters of (meth) acrylic acid such as propyl (meth) acrylate and polyethylene glycol mono (meth) acrylate; unsaturated groups such as di-hydroxyalkyl esters of polycarboxylic acids such as maleic acid and fumaric acid -Containing polyhydroxyalkyl esters; hydroxyl-containing monomers represented by hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, (meth) acrylamide, N, N-dimethyl (meth) acrylia De, N- alkoxymethyl (meth) acrylamide, diacetone acrylamide,
N-methylol (meth) acrylamide, carboxylic acid amide group-containing monomers represented by N, N-dimethyl-p-styrenesulfonamide, etc., p-styrenesulfonamide, N-methyl-p-styrenesulfonamide, etc. Sulfonic acid amide group-containing monomers represented by: N, N-dialkylaminoalkyl (meth) acrylates such as N, N-dimethylaminoethyl (meth) acrylate; or polyvalent carboxylic acids such as maleic anhydride Tertiary amino group-containing monomers represented by adducts with compounds having both an active hydrogen group capable of reacting with an anhydride group-containing monomer and a tertiary amino group, and represented by (meth) acrylonitrile Hydroxy-alkylated α, β-ethylenically unsaturated carboxylic acids such as cyano group-containing monomers and hydroxyalkyl (meth) acrylates Monomers having a phosphoric acid ester group obtained by a condensation reaction between a kill ester and a phosphoric acid ester, monomers having a sulfonic acid group such as 2-acrylamido-2-methylpropanesulfonic acid, methyl (meth) A) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth)
Alkyl (meth) acrylates having a C1-8 linear, branched or cyclic alkyl group such as acrylate; styrene such as styrene, α-methylstyrene, p-tert-butyl-styrene, p-methylstyrene; , Aromatic vinyl compounds such as derivatives thereof, (substituted) aromatic nucleus-containing (meth) acrylates such as benzyl (meth) acrylate, unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid, and monohydric alcohols. Diesters, vinyl acetate, vinyl benzoate,
Vinyl esters such as "Veoba" (vinyl ester manufactured by Shell), olefins such as vinyl chloride, vinylidene chloride, ethylene, propylene, and butadiene; ethylene glycol di (meth) acrylate; propylene glycol di (meth) acrylate; Monomers having two or more polymerizable unsaturated groups in the molecule, such as methylolpropane tri (meth) acrylate, divinylbenzene, trivinylbenzene, diallyl phthalate, vinyltriethoxysilane, γ- (meth) acryloyl Oxypropyltrimethoxysilane, γ- (meth) acryloyloxypropylmethyldimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane,
There are hydrolyzable silyl group-containing monomers such as γ- (meth) acryloyloxypropylmethyldiethoxysilane.

The amount of the monomer (B) that can be copolymerized with the above-mentioned other components may be any mixing ratio except that the fluoroalkyl group-containing ethylenic monomer (A) is used as an essential component. Preferably, the fluoroalkyl group-containing ethylenic monomer (A) is based on the solid content of the aqueous resin dispersion (C).
Is preferably contained in an amount of 1 to 99% by weight. Still more preferably, it contains 0.02% by weight or more of a monomer having two or more polymerizable unsaturated groups in the molecule or a crosslinking monomer such as a hydrolyzable silyl group-containing monomer. Preferably.

The particle size of the aqueous resin dispersion (C) thus obtained is generally in the range of 0.005 to 3 microns.

In order to prepare the aqueous resin dispersion (C) of the present invention,
The required amount of each monomer group may be synthesized in the presence of an emulsifier, a polymerization initiator, and water by the following emulsion polymerization method.

Examples of the emulsifier used in this case include anionic emulsifiers, nonionic emulsifiers, cationic emulsifiers, other reactive emulsifiers, and substances having a surface activity such as acrylic oligomers. And the anionic emulsifier has a low generation of aggregates during polymerization,
It is preferable because a stable emulsion can be obtained. As nonionic emulsifiers, polyoxyethylene alkylphenol ether, polyoxyethylene alkyl ether, polyoxyethylene higher fatty acid ester,
Representative examples include ethylene oxide-propylene oxide block copolymers, and examples of the anionic emulsifier include alkali metal salts of alkyl (benzene) sulfonic acid, alkali metal salts of alkyl sulfate, and alkali metal salts of polyoxyethylene alkyl phenol sulfate. is there. Further, instead of the above-mentioned anionic emulsifier,
Alternatively, a water-soluble oligomer composed of a polycarboxylic acid or a sulfonate can be used in combination. Further, a water-soluble polymer substance such as polyvinyl alcohol and hydroxyethyl cellulose can be used as a protective colloid.
The amount of the above emulsifier and the like is 0.1 to 10 with respect to the total amount of the monomers.
% By weight.

Next, the polymerization initiator is not particularly limited as long as it is generally used for emulsion polymerization. Specific examples thereof include water-soluble inorganic peroxides such as hydrogen peroxide; ammonium persulfate, potassium persulfate, Persulfates such as sodium persulfate; organic peroxides such as cumene hydroperoxide and benzoyl peroxide; and azo-based initiators such as azobisisobutyronitrile and azobiscyanovaleric acid. Or may be used in combination. The amount used is 0.
1-2% by weight is preferred. It is needless to say that a method known as a so-called redox polymerization method using a combination of these polymerization initiators with a metal ion and a reducing agent may be used.

The present invention, in the presence of water, preferably ion-exchanged water and, if necessary, an emulsifier, the monomers individually or in an emulsified state, in a lump, or divided, or continuously dropped into a reaction vessel, The polymerization may be performed at a temperature of 100 ° C. or lower, preferably 30 to 90 ° C. in the presence of the polymerization initiator. The ratio of the total monomer content to water is such that the final solid content is 1 to 60% by weight,
It should preferably be set in the range of 15 to 55% by weight. Further, in order to grow or control the particle diameter in the emulsion polymerization, a seed polymerization method in which emulsion particles are previously present in an aqueous phase and polymerization is performed may be used.

Thus, an aqueous resin dispersion (C) obtained by copolymerizing a fluoroalkyl group-containing ethylenic monomer as an essential component and other copolymerizable monomers in the first step of the present invention can be produced.

Next, as a second step, a monomer mixture (D) containing a fluoroolefin as an essential monomer component is polymerized in the presence of the aqueous resin dispersion (C).

Examples of the fluoroolefin include vinyl fluoride,
Vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, 1,1,3,3,3-pentafluoropropylene, 2,2,3,3-tetrafluoropropylene, 1,1,2-trifluoropropylene, 3, Including fluoroolefins in a pure sense, such as 3,3-trifluoropropylene,
Further chlorotrifluoroethylene, bromotrifluoroethylene, 1-chloro-1,2-difluoroethylene,
Broadly defined fluoroolefins including those having a halogen atom in addition to fluorine, such as 1,1-dichloro-2,2-difluoroethylene, may be mentioned.

Of these, vinylidene fluoride, hexafluoropropylene, 1,1,3,3,3-pentafluoropropylene, 2,2,
3,3-tetrafluoropropyne, 1,1,2-trifluoropropylene, 3,3,3-trifluoropropylene, chlorotrifluoroethylene, bromotrifluoroethylene, 1-chloro-1,2-difluoroethylene And fluoroolefins such as 1,1-dichloro-2,2-difluoroethylene are preferred from the viewpoint of reaction control during polymerization.

Such other monomers copolymerizable with the fluoroolefin should be selected in consideration of copolymerizability with the fluoroolefin, weather resistance of the copolymer, chemical resistance, water resistance, and film forming property. In addition to the above-mentioned monomers, vinyl ethers, vinyl esters, α-olefins and the like can be mentioned.

Examples of vinyl ethers include, for example, methyl-, ethyl-, n-propyl-, isopropyl-, n-butyl-, isoamyl-, n-hexyl-, n-octyl-,
Or alkyl vinyl ethers having various linear or branched alkyl groups such as 2-ethylhexyl-vinyl ether; cycloalkyls having various (alkyl-substituted) cyclic alkyl groups such as cyclopentyl vinyl ether, cyclohexyl vinyl ether or methylcyclohexyl vinyl ether. Alkyl vinyl ethers; aralkyl vinyl ethers such as benzyl vinyl ether or phenethyl vinyl ether;
2,3,3-tetrafluoropropyl vinyl ether, 2,2,
3,3,4,4,5,5-octafluoropentyl vinyl ether, 2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexa Various (per) fluoroalkyl vinyl ethers such as decafluorononyl vinyl ether, perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, perfluoropropyl vinyl ether, perfluorooctyl vinyl ether, or perfluorocyclohexyl vinyl ether; or 4-hydroxybutyl vinyl ether And those having a substituted or unsubstituted alkyl group such as various hydroxyalkyl vinyl ethers.

Examples of vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caproate, vinyl versatate, vinyl laurate, vinyl stearate, pt-
Various vinyl carboxylate esters such as vinyl butyl benzoate, vinyl salicylate, vinyl monochloroacetate, and vinyl cyclohexanecarboxylate are exemplified.

Further, if only typical α-olefins are mentioned, ethylene, propylene, butene-
1 and so on.

Among the various copolymerizable monomers as described above, it is preferable to use vinyl ethers and / or vinyl esters, and more preferably α-olefins in an amount of 30 to 90% by weight and 5 to 20% by weight, respectively.

In this step, the monomer mixture (A) containing the above-mentioned fluoroalkyl group-containing ethylenic monomer as an essential component is emulsion-polymerized in advance by the method described above to obtain an emulsion (C).
Then, the emulsion and a monomer (D) containing a fluoroolefin as an essential component are additionally polymerized, that is, a single step containing a fluoroolefin of a later step as an essential component is formed on the surface of the previously synthesized emulsion. The monomers (D) are deposited and polymerized. In order to obtain the desired product in this step, 50 to 99.9 parts by weight of the monomer mixture (D) may be polymerized in the presence of 0.1 to 50 parts by weight based on the solid content of the component (C). Preferably, the solid content of the aqueous resin dispersion (C) is 2.5 to 50% by weight based on the solid content of the finally obtained fluororesin aqueous dispersion (E).

Further, the fluoroalkyl group-containing ethylenic monomer (A) is contained in the solid component of the fluororesin aqueous dispersion (E) in an amount of from 1 to 3.
Preferably, 30% by weight is introduced.

The amount of the fluoroolefin to be used is preferably 10 to 70% by weight, more preferably 20 to 60% by weight, based on the solid content of the fluororesin aqueous dispersion (E).

The fluororesin aqueous dispersion (E) thus obtained
Has an approximate particle size in the range of 0.01 to 5 microns, and an aqueous dispersion having a uniform particle size distribution can be obtained.

In addition, the monomer copolymerizable as the component (C) or the component (D) includes a fluoroalkyl group-containing ethylenic monomer, copolymerizability with a fluoroolefin, and a finally obtained aqueous coating composition. It is selected in consideration of the durability of the coating film of the product.

For example, it is preferable to crosslink the polymer of the aqueous resin dispersion (C) or the polymer (D) intramolecularly in order to enhance the durability of the obtained coating film. At the time of emulsion polymerization of each of (C) and (D), The crosslinkable monomer was added to each monomer mixture at 0.
It is preferable to use 05 to 2% by weight. More preferably 0.1 to 1.5
It is better to use% by weight. With a usage of less than 0.05% by weight,
The crosslinking effect is not sufficient, and the use of an amount exceeding 2% by weight is not preferred because not only the effect is saturated, but also the film-forming property tends to be impaired.

On the other hand, the finally obtained fluororesin aqueous dispersion (E)
It is preferable to introduce a suitable acidic group into the binder, because the pigment dispersibility of the entire binder can be improved, and the adhesion of the obtained paint to the substrate can be enhanced. That is, (C), (D)
In each emulsion polymerization, it is preferable to use 0.2 to 4% by weight of the ethylenically unsaturated carboxylic acid of the monomer mixture. More preferably, it is used in an amount of 0.5 to 3% by weight, and more preferably, the acid value in terms of solid content of the finally obtained fluororesin aqueous dispersion is 2 to 30.

When the amount is less than 0.2% by weight, the effect is insufficient, and when the amount exceeds 4% by weight, the water resistance and alkali resistance of the obtained coating film are undesirably reduced.

The solid content of each of (C) and (E) is not particularly limited, but is preferably in the range of 20 to 60% by weight of each solid content. Although the polymer Tg of each of (C) and (E) is not particularly limited, both are in the range of −5 ° C. to 60 ° C. in consideration of the balance between the film forming property of the obtained coating film and the stain resistance. preferable.

In the polymerization of the component (d), it is contrary to the gist of the present invention that a large amount of particles of the component (d) alone is produced on a weight basis. Then, the content of component (D) should be 5% by weight or less, preferably 2% by weight or less. When the amount used exceeds 5% by weight, a large amount of emulsion particles of the component (D) alone is formed as a by-product, and an emulsion having two peaks is generated, for example, when the particle size distribution is measured.

The aqueous resin dispersion (C) is obtained by copolymerizing the fluoroalkyl group-containing ethylenic monomer (A),
The affinity with the subsequent monomer (D) containing a fluoroolefin as a main component is improved. Therefore, the monomer containing a fluoroolefin as a main component is efficiently absorbed by the aqueous resin dispersion (C), and the polymerization proceeds, whereby a stable emulsion having a controlled particle size distribution can be synthesized.

The aqueous fluororesin dispersion obtained according to the present invention has a high weather resistance, chemical resistance, and stain resistance of the coating film.
It can be used as a coating agent or a treatment agent for plastics, wood, inorganic substrates, paper, fibers and the like.

Next, the pigment which is another main component of the aqueous coating composition according to the present invention will be described.

Pigment, hardness of the coating film, opacity, improvement of aesthetic appearance by coloring, adhesion to the substrate, chemical resistance, the purpose of improving weather resistance, is appropriately selected and used, but the amount used is 200 with respect to the solid content of the aforementioned fluororesin aqueous dispersion.
It is preferable that the content be not more than weight%. If the amount exceeds 200% by weight, the resulting coating film becomes porous, and the long-term durability such as water resistance is poor, which is not preferable. Some of the pigments used are listed as titanium oxide, mica, talc, clay, precipitated barium sulfate, silica powder, calcium carbonate, iron oxide, zinc oxide, aluminum powder, carbon and other inorganic pigments, azo-based pigments. , Phthalocyanine-based, quinacridone-based organic pigments, or plastic pigments,
It is also possible to use disperse pigments obtained by dispersing these in water with an emulsifier, a dispersant, or the like, and various pigments are selected according to the purpose and used.

In addition, various additives necessary for forming a coating, for example, dispersing agents, wetting agents, film forming aids, thickening agents, thixotroping agents, ultraviolet absorbers, antioxidants, solutions, antifreezing agents, preservatives / soiling agents The use of an agent, an antifoaming agent or the like is selected and used in consideration of the performance of the obtained coating film.

The substrate to be coated with the composition is typically a metal, plastic, wood, glass, cement substrate, paper, fiber or the like. As a method of coating, brush coating, spray coating, coating with a roll or a flow coater, it is possible to lower the coating by dip coating such as dipping, and after coating, if necessary, after a setting time, A film can be obtained by drying by heating or drying at room temperature. When drying by heating, drying may be performed at a temperature of 60 to 200 ° C. for an arbitrary time.

(Example) Hereinafter, the present invention will be described with reference to examples. All parts are on a weight basis.

Example 1 (Synthesis of an aqueous resin dispersion (A) containing a fluoroalkyl group-containing ethylenic monomer as an essential component) The inside of the system was sufficiently replaced with nitrogen gas in a stainless steel reaction vessel, and 730 g of ion-exchanged water and 10 g of sodium dodecylbenzenesulfonate were charged and dissolved.
Heat to ° C. In advance, 400 g of octafluorobutyl methacrylate, 300 g of methyl methacrylate, 280 g of ethyl acrylate, 20 g of methacrylic acid were obtained by adding 250 g of ion-exchanged water, polyoxyethylene nonyl phenyl ether 10
g and 10 g of sodium dodecylbenzenesulfonate are introduced into and emulsified in an emulsifier solution containing 10 g of sodium dodecylbenzenesulfonate, and an aqueous catalyst solution is prepared by dissolving 5 g of ammonium persulfate in 20 g of ion-exchanged water. At the same temperature, the monomer mixture,
The polymerization reaction is performed by dropping the catalyst aqueous solution over 3 hours. After the completion of the dropwise addition, the temperature is maintained at the same temperature for 3 hours to complete the polymerization reaction.

The obtained product was a milky white liquid having a nonvolatile content of 50.6% and a pH of 2.5. Hereinafter, this is referred to as (A-1).

Example 2 (Production of aqueous fluororesin dispersion) A 21 stainless steel autoclave obtained in Example 1 (A
Prepare 200 parts of -1). Next, 15 parts of sodium dodecylbenzenesulfonate, 6 parts of polyoxyethylene nonylphenol ether (HLB17), 3 parts of ammonium bicarbonate, and 690 parts of ion-exchanged water were charged. It was stirred and degassed with nitrogen. 9 parts of methacrylic acid and 48
Parts of Veovar 9 (Versatic acid vinyl ester, Shell, Netherlands), 260 parts of vinyl acetate, 3 parts of 1.7-
Octadiene and liquefied and collected 400 parts of chlorotrifluoroethylene were put into a pressure-resistant drip tank, and ethylene was further injected into the autoclave so as to have a pressure of 30 atm. The autoclave was heated to 65 ° C., and while stirring, a solution prepared by dissolving 5 parts of ammonium persulfate in 90 parts of ion-exchanged water and a monomer placed in a pressure dropping tank were added dropwise over 6 hours. The temperature was maintained at the same temperature for a time to complete the reaction. After cooling to room temperature, the pH of the reaction mixture was adjusted to 7.5 with 14% aqueous ammonia. The resulting product was a milky white liquid with a non-volatile content of 46%, an average particle size of 0.17 microns and a narrow particle size distribution. Hereinafter, a sample prepared by preparing the composition with a nonvolatile content of 45% (C
-1).

Example 3 (Production of Fluororesin Aqueous Dispersion) In the same reaction vessel as in Example 2, (A-
Prepare 100 parts of 1). Next, 20 parts of sodium dodecylbenzenesulfonate, 8 parts of polyoxyethylene nonylphenol ether (HLB14), 3 parts of ammonium bicarbonate and 800 parts of ion-exchanged water were charged and dissolved by stirring, followed by degassing with nitrogen. 12 parts of crotonic acid and 100 parts of Veovar 9
(Vasatic acid vinyl ester, Shell, Netherlands), 210 parts of vinyl acetate, 5 parts of 1.7-octadiene,
Put 420 parts of the liquefied and collected chlorotrifluoroethylene into the pressure-resistant drip tank, and further add ethylene to the autoclave for 30 minutes.
Pressurized to reach atmospheric pressure. The autoclave was heated to 65 ° C., and while stirring, a solution prepared by dissolving 5 parts of ammonium persulfate in 90 parts of ion-exchanged water and a monomer placed in a pressure dropping tank were added dropwise over 6 hours. The temperature was maintained at the same temperature for a time to complete the reaction. After cooling to room temperature, the pH of the reaction mixture was adjusted to 7.5 with 14% aqueous ammonia. The resulting product was a milky white liquid having a nonvolatile content of 45%, an average particle size of 0.21 micron and a narrow particle size distribution. Hereinafter, this is referred to as (C-2).

Comparative Example 1 A reaction was carried out using the same raw materials and operation as in Example 2, except that 200 parts of (A-1) were not used. The product was a milky liquid with a particle size distribution of 42% non-volatiles and an average particle size of 0.07 microns.

However, a large number of coarse particles having a particle size of 0.5 to 1 mm were generated in the autoclave, and a large amount of floc was attached to the inner wall and the stirring blade of the autoclave. This was concentrated under reduced pressure, and the pH was further adjusted to 7.5 to obtain a comparative fluororesin aqueous dispersion (R-1) having a nonvolatile content of 45%.

Example 4 (Blending of water-based coating composition) The aqueous dispersions of fluororesins obtained in Examples 2, 3 and Comparative Examples were variously blended according to the following paint formulations A, B, and C.

[Painting formulation A] (white glossy paint for normal drying) Water 7.84 parts 25% ammonia water 0.15 parts Inogen EA-120 0.33 parts (wetting agent: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) Tamol 731 (25%) 1.34 parts ( Dispersant: Rohm and Haas, USA) Ethylene glycol 7.46 parts Taipaque R930 41.00 parts (Titanium dioxide: Ishihara Sangyo) Best side FX 0.22 parts (Preservative: Dainippon Ink and Chemicals, Inc.) NOPCO 8034 0.30 parts (Foaming agent: manufactured by San Nopco) The above was dispersed by a high-speed stirrer.

Cellosize QP-4400 (3%) 7.46 parts (Thickener: VCC, USA) Nitrogen Sizer CS-12 4.00 parts (Film forming aid: Chisso) Butyl carbitol acetate 3.40 parts (Film forming aid) 100.00 parts or more of the resin dispersion (45%) were uniformly stirred with a stirrer.

Paint non-volatile content: 51% Pigment concentration PWC: 47% [Painting composition B] (Blending black glossy paint for forced drying by heating) Water 11.50 parts Water-based resin dispersion (45%) 100.00 parts Butyl carbitol acetate 1.50 parts (Film formation Auxiliary agent) Disperse Color SD-9020 0.15 parts (Carbon dispersed pigment: manufactured by Dainippon Ink and Chemicals, Inc.) NOPCO 8034L 0.01 parts (antifoaming agent: manufactured by San Nopco) Best Side FX 0.20 parts (preservative: Dainippon Ink and Chemicals) 0.33 parts of Neugen EA-120 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) The above was uniformly stirred with a stirrer.

Paint non-volatile content: 40% Pigment concentration PWC: 1% [Painting formulation C] (formulation of white glossy coating for heat-dried metal) Water 3.00 parts Butyl cellosolve 6.00 parts Tamol 731 (25%) 0.50 parts (Dispersant) Waterzole S −352 (65%) 3.00 parts (dispersion, water-soluble resin: manufactured by Dainippon Ink and Chemicals, Inc.) Dimethylethanolamine 0.05 parts Formaster VL 0.10 part (antifoaming agent: manufactured by San Nopco) Taipaek R-930 41.00 parts ( (Titanium dioxide: manufactured by Ishihara Sangyo Co., Ltd.) The above was dispersed with a sand glider.

Aqueous resin dispersion (45%) 100.00 parts Dicnate 3111 3.00 parts (Dryer: manufactured by Dainippon Ink and Chemicals, Inc.) The above was uniformly stirred with a stirrer.

Paint non-volatile content: 51% Pigment concentration PWC: 31% Example 5 The various water-based paints obtained in Example 4 and Comparative Example 1 were applied to various substrates, and were used in the tests. The results are summarized in Table 1.

(Substrate) Base material a: Slate plate Base material b: Acrydic A- as a sealer on the slate plate
172 (solvent-based acrylic resin; Dainippon Ink and Chemicals, Inc.) is applied at 100 g / m ² , and after drying, luffon jumbo (spray tile; Suzuka Paint Co., Ltd.) is applied smoothly at 2000 g / m ² , One week dried at room temperature.

Substrate c: Mild soft steel sheet (Coating method) In the case of coating composition A Each of the substrates a, b, and c was coated with the aqueous coating composition at room temperature for 12 minutes.
After coating at 0 g / m ² and drying for 1 day, it was further coated at 80 g / m ² , dried at room temperature for 7 days, and used for various tests.

In the case of coating composition B: The base material a was preheated to a surface temperature of 60 ° C. in advance, the aqueous coating composition was coated to 120 g / m ^2, and dried by heating at 100 ° C. for 10 minutes. After leaving it to cool at room temperature for 5 minutes, it was further coated to 80 g / m ² and dried by heating at 100 ° C. in an atmosphere. It was dried at room temperature for 7 days and used for various tests.

In the case of the coating composition C, the coating was performed in the same manner as described above using the base material c, and subjected to various tests.

(Coating film test method) The test pieces coated on various base materials under various conditions were left with the coated surface, and the other surface was sealed with a urethane-acrylic sealing agent and then subjected to the following test.

Water resistance: After dipping in tap water for 2 months, the state of the coating film was visually judged.

Acrylic resistance: After dipping in a 2% aqueous NaOH solution saturated with Ca (OH) ₂ for 2 months, the state of the coating film was visually judged.

Acid resistance: After immersion in a 0.2% aqueous sulfuric acid solution for one month, the state of the coating film was visually judged.

Freezing and thawing resistance: Immerse in water, -20 ℃ × 4 hours → 40 ℃
× 4 hours was defined as one cycle, and the state after 30 cycles was visually determined.

Accelerated weather resistance: After an accelerated test with a sunshine weather meter, the gloss retention at each test time was measured.

Actual exposure test: Exposure was performed outdoors in Takaishi City, Osaka Prefecture for 2 years, and the state of contamination of the coating film was visually determined.

(Effects of the Invention) The fluororesin aqueous dispersion of the present invention facilitates control of the particle size of the fluoroolefin-based emulsion copolymer, which has been difficult so far, and can be adjusted to an arbitrary particle size. Therefore, the aqueous resin dispersion of the present invention can provide a fluororesin aqueous dispersion having an appropriate particle size according to various required performances of the aqueous resin composition having different purposes.

Continuation of front page (56) References JP-A-2-274711 (JP, A) JP-A-63-280714 (JP, A) JP-A-59-232109 (JP, A) JP-A-52-62391 (JP, A) , A) (58) Fields studied (Int. Cl. ⁶ , DB name) C08F 251/00-292/00

Claims (18)

(57) [Claims] 1. An aqueous resin dispersion (C) obtained by copolymerizing a fluoroalkyl group-containing ethylenic monomer (A) and another polymerizable monomer (B), and A fluororesin aqueous dispersion (E) obtained by emulsion polymerization of a monomer mixture (D) containing an olefin as an essential component. 2. The method according to claim 1, wherein the ethylenic monomer of the fluoroalkyl group-containing ethylenic monomer (A) is one or a mixture of two or more of vinyl ether, vinyl ester and (meth) acrylate. The fluororesin aqueous dispersion (E) according to claim 1, wherein 3. The fluoroalkyl group-containing ethylenic monomer (A) is contained in the solid content of the fluororesin aqueous dispersion (E) in an amount of from 1 to 3.
The fluororesin aqueous dispersion (E) according to claim 1 or 2, which is contained in an amount of 30% by weight. 4. The method according to claim 1, wherein the solid content of the aqueous resin dispersion (C) is 2.5 to 50% by weight based on the solid content of the fluororesin aqueous dispersion (E). 2. The fluororesin aqueous dispersion (E) according to 1. 5. The fluoroolefin is vinylidene fluoride,
Hexafluoropropylene, 1,1,3,3,3-pentafluoropropylene, 2,2,3,3-tetrafluoropropylene,
1,1,2-trifluoropropylene, 3,3,3-trifluoropropylene, chlorotrifluoroethylene, bromotrifluoroethylene, 1-chloro-1,2-difluoroethylene, 1,1-dichloro-2,2 The fluororesin aqueous dispersion (E) according to any one of claims 1 to 4, wherein the fluororesin aqueous dispersion (E) is one or more selected from -difluoroethylene. 6. The fluororesin aqueous dispersion according to claim 1, wherein the fluoroolefin is contained in the solid content of the fluororesin aqueous dispersion (E) in an amount of 20 to 60% by weight. Body (E). 7. The fluororesin aqueous dispersion (E) according to claim 1, wherein the acid value of the aqueous fluororesin dispersion (E) in terms of solid content is 2 to 30. . 8. The method according to claim 1, wherein the monomer mixture (D) containing a fluoroolefin as an essential component contains 0.05 to 2% by weight of a crosslinkable monomer. Fluororesin aqueous dispersion (E). 9. An aqueous resin dispersion (C) is prepared by copolymerizing a fluoroalkyl group-containing ethylenic monomer (A) and another polymerizable monomer (B). A process for producing a fluororesin aqueous dispersion (E), which comprises emulsion-polymerizing a monomer mixture (D) containing a fluoroolefin as an essential component in the presence of a body (C). 10. The fluoroalkyl group-containing ethylenic monomer (A) is contained in a solid text of the fluororesin aqueous dispersion (E) in a solid form.
The method for producing a fluororesin aqueous dispersion according to claim 9, wherein the content of the fluororesin is from 30 to 30% by weight. 11. The process for producing an aqueous fluororesin dispersion according to claim 9, wherein the fluoroolefin is contained in the solid content of the aqueous fluororesin dispersion (E) in an amount of 20 to 60% by weight. . 12. The solid content of the aqueous resin dispersion (C) is 2.5 to 50% by weight based on the solid content of the fluororesin aqueous dispersion (E).
The method for producing a fluororesin aqueous dispersion according to any one of claims 9 to 11, wherein 13. The fluoroolefin is hexafluoropropylene, 1,1,3,3,3-pentafluoropropylene,
2,3,3-tetrafluoropropylene, 1,1,2-trifluoropropylene, 3,3,3-trifluoropropylene, chlorotrifluoroethylene, bromotrifluoroethylene, 1-chloro-1,2-difluoroethylene 13. The fluororesin aqueous dispersion (E) according to any one of claims 9 to 12, wherein the fluororesin aqueous dispersion (E) is one or more selected from 1,1-dichloro-2,2-difluoroethylene. Method. 14. The fluororesin aqueous dispersion (E) has an acid value of 2 to 30 in terms of solid content, wherein the acid value is 2 to 30.
The method for producing an aqueous dispersion of a fluororesin according to any one of the preceding claims. 15. The method according to claim 9, wherein the monomer mixture (D) containing a fluoroolefin as an essential component contains 0.05 to 2% by weight of a crosslinkable monomer. A method for producing a fluororesin aqueous dispersion. 16. An aqueous resin composition comprising the fluororesin aqueous dispersion (E) according to any one of claims 1 to 8 as an essential component. 17. The aqueous resin composition according to claim 16, comprising a fluororesin aqueous dispersion (E) and a pigment of 200% by weight or less based on the solid content of the fluororesin aqueous dispersion (E). 18. An article coated with the aqueous resin composition according to claim 16. Description: