JPH0641490A - Cold-curable fluororesin water-based coating composition and article coated with the composition - Google Patents

Abstract

(57) [Summary] [Structure] An aqueous resin dispersion obtained by copolymerizing a fluoroolefin, crotonaldehyde and / or alkenals, and other copolymerizable monomers,
For example, a room temperature curable fluororesin water-based coating composition comprising hydrazine or ethylene-1,2-dihydrazine and the like, and an article coated with the composition. [Effect] Not only the weather resistance but also the strong film-forming state due to the interparticle cross-linking makes it particularly excellent in boiling water resistance and solvent resistance, and further, these properties can be maintained for a long time. Thus, highly practical paints and coated articles can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel and useful room temperature-curable fluororesin aqueous coating composition, and an article coated with the aqueous resin composition. More specifically,
The present invention is based on a fluoroolefin and a specific formyl group-containing ethylenic monomer such as crotonaldehyde and / or alkenal, and, if necessary, a monomer based on a crosslinkable monomer. An aqueous dispersion of a fluororesin obtained by polymerization; a hydrazine and / or a compound having at least two hydrazyl groups in one molecule; as an essential component, in particular, weather resistance and water resistance of a coating film and The present invention relates to a room temperature curable fluororesin water-based coating composition having excellent solvent resistance and the like, and an article coated with the water-based coating composition.

[0002]

2. Description of the Related Art The purpose of coating the surface of a so-called alkaline inorganic hardened material such as metal or cement or plastic is mainly to improve the so-called durability such as weather resistance, chemical resistance or water resistance of a base material. This is for the sake of brevity, but of course, it is considered in a total form that also includes protection and beauty.

In recent years, in particular, as a coating agent for outdoor exposure such as building exterior materials and industrial materials,
Long-term maintenance-free products with excellent durability have been demanded.

Of these, fluoroolefin copolymers (so-called fluororesins) are known as binders that provide high weather resistance and high chemical resistance, and are mainly sold in the form of an organic solvent solution on the market. There is.

However, since a large amount of organic solvent is contained, there are problems such as fire hazard, harmfulness, and air pollution, so that an aqueous binder is required.

Although aqueous dispersions of various fluoroolefin polymers obtained by using tetrafluoroethylene, vinylidene fluoride, hexafluoropropylene, etc. have been proposed, all of these are Baking at high temperature is necessary. For example, in the invention described in JP-A-57-38845, in the case of a copolymer of vinylidene fluoride and hexafluoropropylene, its intrinsic viscosity is [Η] is 0.1
Despite the low molecular weight of 0.5, still 180 ~
Baking at a temperature of 230 ° C is inevitable.

Of course, such high temperature baking is not possible in the field of normally dry paints that are painted on site, and in addition, it is economically disadvantageous even in factory line painting which is basically dried by heating.

On the other hand, JP-A-61-261367 proposes a coating composition based on an emulsion polymer composed of fluoroolefin, alkyl vinyl ether and vinyl carboxylic acid ester as a solution to such a problem. Therefore, although the film-forming property at low temperature has been greatly improved, it is difficult to obtain a film having a sufficient film-forming degree at room temperature, and the solvent resistance is also insufficient.

On the other hand, JP-A-2-214756 proposes an aqueous coating composition containing an aqueous dispersion of a fluororesin resin having a carbonyl group in the molecule and a hydrazine compound. Although there is cross-linking between particles, the copolymerizability of the carbonyl group-containing monomer is poor, which leads to a decrease in the degree of polymerization and the polymerization rate, and eventually the physical properties of the coating film deteriorate. Therefore, it cannot be said to be sufficient.

[0010]

Therefore, a water-based coating having a strong intergranular bond even at room temperature and capable of sufficiently satisfying the durability of the coating film such as water resistance and solvent resistance. The reality is that the agent does not currently exist.

However, the present inventors have made room temperature-curable fluorine excellent in water resistance, especially boiling water resistance, solvent resistance, etc. by forming crosslinks between emulsion particles under the condition of room temperature drying. In earnest, the research was started in search of a novel technique of providing a resin water-based coating composition and a coated article.

[0012] Therefore, the object of the present invention and the problems to be solved by the present invention are, in essence, weather resistance and
Excellent durability in a total sense, that is, water resistance including boiling water resistance, and excellent solvent resistance and chemical resistance, etc., a highly practical room temperature curable fluororesin water-based coating composition, And to provide an article coated with the composition.

[0013]

Therefore, the present inventors have
In view of the advantages and disadvantages of the conventional technology, moreover, focusing on the problems to be solved by the present invention described above,
As a result of earnest and repeated studies, the drawbacks of the conventional fluoroolefin-based aqueous resin dispersions in film-forming property, the aqueous resin dispersions in the form of emulsion polymerization of a specific monomer mixture, and a specific curing agent The water-based coating composition consisting of and, even under intended dry conditions at room temperature, can cause interparticle cross-linking to form a strong film-forming state, as well as water resistance and solvent resistance, etc. However, it was found that the durability of the coating film could be improved, and the present invention was completed here.

[Structure] That is, the present invention basically comprises a fluoroolefin, crotonaldehyde and / or alkenal, a specific formyl group-containing ethylenic monomer, and other copolymerizable monomer. A room temperature curable fluorine comprising an aqueous resin dispersion obtained by emulsion-polymerizing a body and hydrazine and / or a compound having at least two hydrazide groups in one molecule as essential film-forming components. The present invention is intended to provide a resin water-based coating composition, and also to provide an article coated with the room temperature-curable fluororesin water-based coating composition.

As described above, according to the present invention, first, an aqueous resin dispersion obtained by emulsion-polymerizing a mixture of specific monomer components and at least two in a molecule, represented by dihydrazide of dicarboxylic acid. By mixing with a compound having a hydrazide group and / or hydrazine,
A normal temperature-curable fluororesin aqueous dispersion is prepared.

To cite only the particularly representative fluoroolefins mentioned above,
Vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, 1,1,3,3,3
-Including fluoroolefins in the pure sense, such as pentafluoropropylene, 2,2,3,3-tetrafluoropropylene, 1,1,2-trifluoropropylene or 3,3,3-trifluoropropylene,

Further, chlorotrifluoroethylene,
A so-called broad sense including compounds having a halogen atom other than a fluorine atom, such as bromotrifluoroethylene, 1-chloro-1,2-difluoroethylene or 1,1-dichloro-2,2-difluoroethylene. And fluoroolefins.

Hexafluoropropylene, 1, among others
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 or 1 , 1-dichloro-2,2-difluoroethylene and other fluoroolefins, more preferably hexafluoropropylene, chlorotrifluoroethylene, vinylidene fluoride and the like are suitable from the viewpoint of reaction control during polymerization. is there.

The proportion of fluorine atoms in the fluoroolefin copolymer, that is, the fluorine content in the copolymer, itself has an influence on the coating film obtained, especially on the weather resistance. From a large point, it is desirable that the fluorine content is approximately 4% by weight or more.

From this point of view, the amount of fluoroolefins used is appropriately in the range of 10 to 80% by weight based on the total monomers.

On the other hand, among the other monomers copolymerizable with the fluoroolefins, various kinds can be considered as particularly main ones, and the kind and amount thereof have high weather resistance, It should be selected in consideration of various film performances such as chemical resistance, water resistance, alkali resistance, heat resistance and flexibility, and it is particularly typical as such a main copolymerizable monomer. The following is only an example.

(1) Various unsaturated carboxylic acids and their esters such as crotonic acid, itaconic acid, citraconic anhydride or itaconic anhydride, and (2) various unsaturated groups such as citraconic acid or itaconic acid. Various unsaturated group-containing polyhydroxyalkyl esters such as di-hydroxyalkyl esters of contained polycarboxylic acids, (3) methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, Isoamyl vinyl ether, n-hexyl vinyl ether, n-
Various alkyl vinyl ethers such as octyl vinyl ether, 2-ethylhexyl vinyl ether, cyclopentyl vinyl ether, cyclohexyl vinyl ether, methylcyclohexyl vinyl ether, benzyl vinyl ether or phenethyl vinyl ether,

Various (per) fluoroalkyl vinyl ethers such as perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, perfluoropropyl vinyl ether, perfluorooctyl vinyl ether or perfluorocyclohexyl vinyl ether, or various kinds such as 4-hydroxybutyl vinyl ether. Various vinyl ethers such as hydroxyalkyl vinyl ethers of (4) vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caproate, vinyl neononanoate,
Such as vinyl neodecanoate, vinyl laurate, vinyl stearate, vinyl 2-ethylhexanoate, vinyl pt-butyl benzoate, vinyl salicylate, vinyl monochloroacetate or vinyl cyclohexanecarboxylate,
Various carboxylic acid vinyl esters,

(5) Various (halogenated) olefins such as vinyl chloride, vinylidene chloride, ethylene, propylene, 1-butene and isobutene, or (6) butadiene, hexadiene, octadiene, decadiene,
Various crosslinkable monomers having two or more polymerizable unsaturated groups in the molecule, such as tetradecadiene, 2-methyloctadiene, decatriene or diallylphthalate, vinyltrimethoxysilane, vinyltriethoxysilane. Alternatively, there are various crosslinkable monomers of a different type from the above, such as various hydrolyzable silyl group-containing monomers such as vinyltris (2-methoxyethoxy) silane.

Of the various copolymerizable monomers described above, preferably vinyl ethers and / or vinyl esters, and further olefins, preferably 5 to 90% by weight, respectively. It is suitable to use within the range of, and more preferably within the range of 5 to 20% by weight.

Among these various copolymerizable monomers, vinyl ethers are easily hydrolyzed under certain conditions when used in an aqueous medium. It is further desirable to use other copolymerizable monomers other than the Els.

In addition to the above, examples of the copolymerizable monomers include fluoroalkyl group-containing ethylenic monomers. In that case, the copolymerizability with fluoroolefin and the final It should be selected in consideration of the durability of the coating film of the aqueous coating composition obtained in 1.

The above-mentioned crotonaldehyde and / or the specific formyl group-containing monomers
Alternatively, among alkenals, 6-heptenal, 10-undecenal, and the like are given as examples of only typical alkenals.

Carbonyl group- and formyl group-containing monomers such as various acrylic acid derivatives such as acrolein, diacetone acrylamide or formyl styrene, styrene derivatives, etc. are fluoroolefins, carboxylic acid vinyl esters, etc. It is not preferred because the copolymerizability with and is not sufficient, and therefore the use of these compounds should be avoided.

The amount of the formyl group-containing monomers to be used is 0.01 to 20% by weight, preferably 0.5 to 10% by weight, and more preferably 0.5 to 10% by weight based on all the monomers.
A range of 7% by weight is suitable.

If the amount is less than 0.01% by weight, the effect of using the monomers is difficult to be realized.
On the other hand, when it is used in an excessively large amount exceeding 20% by weight, not only the effect is saturated, but also the flexibility of the obtained coating film is liable to be decreased, which is not preferable.

The crosslinkable monomers are desirable in order to enhance the durability of the coating film obtained, and the crosslinkable monomers are preferably added to the monomer mixture in an amount of 0.1 to 0.1 at the time of emulsion polymerization. It is also possible to use within the range of 2% by weight. 0.1% by weight
If the amount used is less than the above, the crosslinking effect is not sufficient. On the other hand, if the amount used exceeds 2% by weight, not only the effect is saturated, but also the film-forming property tends to be impaired. Therefore, either case is not preferable.

The above-mentioned crosslinkable monomers referred to here are those which cause crosslinking within the emulsion particles,
Through such crosslinking, the durability of the particles is improved.

In this sense, the so-called "inter-particle cross-linking", which is achieved by using the room temperature-curable fluororesin water-based coating composition of the present invention as a coating and is carried out via a formyl group, is as described above. It can be said that the so-called "intraparticle crosslinking" by the crosslinkable monomers is a completely different dimension.

The solid content of the room temperature-curable fluororesin aqueous coating composition of the present invention (hereinafter, also referred to as an aqueous resin dispersion or an aqueous dispersion) is not particularly limited.
Practically, the solid content is preferably in the range of 20 to 60% by weight.

The Tg of the copolymer constituting the aqueous resin dispersion of the present invention is not particularly limited, but within the range of -20 ° C to + 60 ° C in consideration of the film forming property of the coating film obtained. Is desirable.

To prepare the aqueous resin dispersion,
A required amount of monomers selected from the above-mentioned various monomer groups may be carried out in the presence of an emulsifier, a polymerization initiator and water by an emulsion polymerization method as shown below.

The representative emulsifiers used in this case are anionic emulsifiers, nonionic emulsifiers or cationic emulsifiers, or other reactive emulsifiers or fluorine-based surfactants. And various substances having surface-active properties such as acrylic oligomers. Among them, nonionic and / or anionic emulsifiers are aggregates during polymerization. It is particularly desirable since it produces less emulsion and a stable emulsion can be obtained.

As the above-mentioned nonionic emulsifiers, only typical ones are exemplified. Polyoxyethylene alkylphenol ether, polyoxyethylene alkyl ether, polyoxyethylene higher fatty acid ester, ethylene oxide-propylene oxide block copolymer Examples of the anionic emulsifying agent include polymers such as alkyl (benzene) sulfonic acid alkali metal salts, and the like.
Alkyl sulfate alkali metal salts, polyoxyethylene alkylphenol sulfate alkali metal salts and the like.

Further, various water-soluble oligomers composed of polycarboxylic acid or sulfonate can be used instead of the above-mentioned anionic emulsifier or in combination with them.

Furthermore, various water-soluble polymeric substances such as polyvinyl alcohol or hydroxyethyl cellulose can be used as the protective colloid. The amount of the emulsifiers and the like listed above is about 0.1 to 10% by weight based on the total amount of the monomers.

Next, the above-mentioned polymerization initiator is not particularly limited as long as it is one generally used in emulsion polymerization, but if only typical ones among them are given as examples, the peroxidation will be carried out. Various water-soluble inorganic peroxides such as hydrogen; Various persulfates such as ammonium persulfate, potassium persulfate or sodium persulfate; Various organic peroxides such as cumene hydroperoxide or benzoyl peroxide Kinds; various azo initiators such as azobisisobutyronitrile or azobiscyanovaleric acid, and these may be used alone or in combination of two or more.

The amount of the polymerization initiator used is appropriately within the range of 0.1 to 2% by weight based on the total amount of the monomers. It is needless to say that a method well known as a so-called redox polymerization method in which these polymerization initiators are used in combination with a metal ion and a reducing agent may be used.

In the present invention, in the presence of water, preferably ion-exchanged water, optionally in the coexistence of an emulsifier, the monomers are separately or in an emulsified state, either collectively or collectively. It is added dropwise to the reaction vessel in a divided manner or continuously, and 0-1 in the presence of the above-mentioned polymerization initiator.
At a temperature of 00 ° C, preferably 30 to 90 ° C, 3
~ 100 Kg / cm ² , preferably 6-50 Kg / c
Polymerization may be performed at a pressure of m ² .

The ratio of total monomer content to water should be set so that the final solid content is in the range of 20 to 60% by weight. Further, in carrying out emulsion polymerization, a seed polymerization method may be used in which emulsion particles are preliminarily allowed to exist in an aqueous phase for polymerization in order to grow or control the particle diameter.

The particle size of the aqueous resin dispersion thus obtained is generally in the range of 0.05 to 3 microns (μm). A compound containing at least two hydrazine and hydrazyl groups in one molecule undergoes a cross-linking reaction with the formyl groups contained in the aqueous resin dispersion as the coating film dries, making the film formation stronger and improving the mechanical properties of the initial film formation. It is for improving physical properties of the coating film such as dynamic strength and water resistance.

Therefore, such hydrazine and / or
Or, if only representative examples of compounds having two or more hydrazyl groups (—NHNH ₂ ) in one molecule (hereinafter also referred to as hydrazyl group-containing compounds) are given, oxalic acid dihydrazide, malonic acid Dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide,
Various dihydrazides of dicarboxylic acids such as adipic acid dihydrazide and sebacic acid dihydrazide; Di- or trihydrazides of tricarboxylic acids; Various dihydrazides of disulfonic acids such as bis (hydrazinesulfonyl) benzene; Disulfonic acids of trisulfonic acid -Or trihydrazides;

Various dihydrazine adducts of diepoxy compounds such as dihydrazine adducts such as diglycidyl ether; di- or trihydrazine adducts of triepoxy compounds; C ₂ -C ₅ carbonic dihydrazides Bissemicarbazides; ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, butylene-1,4-dihydrazine, and further polycarboxylic acid polyhydrazides; polysulfonic acid polyhydrazides And so-called polymer compounds.

The amount of the hydrazyl group-containing compound used is such that the amino group derived from the hydrazyl group is 0.0 per 1 mol of the formyl group contained in the aqueous resin dispersion.
The amount corresponding to 1 to 5 mol is suitable, and more preferably, the amount corresponding to 0.1 to 2 mol is suitable. 0.01
If the amount is less than the molar amount, the effect of crosslinking is insufficient, while if the amount exceeds 5 mol, not only the effect is saturated, but rather the strength of the coating film is lowered.
Either case is not preferable.

Further, as a more preferable kind of the hydrazyl group-containing compound, one having a certain degree of water solubility is suitable, and examples thereof include hydrazine, malonic acid dihydrazide and glutar. There are acid dihydrazide, carbonic acid dihydrazide, bissemicarbazide, ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, butylene-1,4-dihydrazine, and the like, and more preferably hydrazine, carbonic acid dihydrazide, bissemicarbazide. , Ethylene-1,2-dihydrazine or propylene-1,3-dihydrazine.

Next, the above-mentioned pigments, which are one of the further main constituents of the aqueous coating composition, will be explained. Such pigments have a coating film hardness, hiding property, improved aesthetics due to coloring, adhesion to a substrate,
It is appropriately selected and used according to the purpose of improving chemical resistance or weather resistance, and the amount thereof is 200% based on the solid content of the above-mentioned aqueous resin dispersion.
It is desirable that the content is not more than weight%. If the amount is more than 200% by weight, the resulting coating film tends to be porous, and the long-term durability such as water resistance is deteriorated.

As the pigments to be used, only typical ones are exemplified, and titanium oxide, mica, talc, clay, precipitated barium sulfate, silica powder,
Inorganic pigments such as calcium carbonate, iron oxide, zinc oxide, aluminum powder, and carbon; or organic pigments such as phthalocyanine blue, or these various pigments with an emulsifier and / or a dispersant. Thus, so-called dispersed pigments in the form of being dispersed in water can be used, and they are appropriately selected and used according to their respective purposes.

As various additives necessary for forming a coating material, for example, dispersants, wetting agents, film-forming aids,
The use of thickeners, thixotropic agents, ultraviolet absorbers, antioxidants, water repellents, antifreezing agents, antiseptic or anti-foaming agents, defoaming agents, etc. is a coating film obtained. It should be appropriately selected and used in consideration of various performances.

Next, regarding the coating method, first, as the base material, various kinds of alkaline inorganic hardened materials such as concrete skeleton, wall material or roof material, or metal plates, etc. As long as it is a base material, it is not particularly limited, and then, as the coating means, known and commonly used means such as brush coating, roller coating, spray coating, roll coater coating or showering coating can be adopted. Depending on the situation, the base material and means of
Just select it.

At this time, as a composition for construction at a construction site, so-called room temperature drying type, the minimum film forming temperature of the room temperature curable fluororesin water-based coating composition is 0 ° C. or lower. It is desirable to use a brush, a roller, or a spray as a coating method. The drying condition is 0 ° C. or higher, preferably 20.
Drying at 7 ° C or above for 7 days gives a completely cured coating film.

On the other hand, it can also be used for so-called factory line painting on roofing materials such as roof tiles and wall materials, and according to the drying conditions according to the generally used forced heating drying method. It is desirable to select and use a paint prepared so that the minimum film-forming temperature of the water-based paint composition is generally 60 ° C. or lower, preferably 50 ° C. or lower. As a coating method, a roll coater, a roller It is better to use a method such as spraying or showering.

Further, the aqueous coating composition may be directly coated on the substrate in one coat or in multiple coats, or an acrylic or acrylic-styrene copolymer system. , Acrylic-urethane combination system, silicone-
Generally, a primer or base coat (undercoat) using a coating material containing a binder with good alkali resistance, such as an acrylic combination type, epoxy type, urethane type or silicon type, as a top coat Alternatively, the water-based coating composition may be applied to improve the weather resistance of the entire coating system.

Regardless of which coating system is used, a dry thick film of the aqueous coating composition of 5 μm or more is suitable. If it is less than 5 μm,
This is because the long-term durability of the coating tends to be inadequate.

Thus, according to the method of the present invention, the room-temperature-curable fluororesin water-based coating composition is excellent in various film properties such as super weather resistance, water resistance and boiling water resistance, and has extremely high practicality. An article coated with the composition is obtained.

[0060]

EXAMPLES Next, the present invention will be explained more concretely by reference examples, examples and comparative examples. In the following, all parts are based on weight unless otherwise specified.

Reference Example 1 In a 2-liter stainless steel autoclave, 720 parts of ion-exchanged water, 16 parts of sodium dodecylbenzenesulfonate, 8 parts of polyoxyethylene nonylphenol ether (HLB = 17) and ammonium hydrogencarbonate were added. Was charged and dissolved, and the inside of the container was degassed with nitrogen.

Then, 8 parts of crotonic acid, "Veoba
9 "(a vinyl ester of a branched saturated aliphatic carboxylic acid manufactured by Shell Co., Netherlands) and 16 parts of crotonaldehyde and 320 parts of liquefied and collected vinylidene fluoride were put in a pressure-resistant dropping tank. Further, ethylene was forced into the autoclave at a pressure of 15 atm.

Thereafter, the autoclave was heated to 80 ° C., and while stirring, 5.6 parts of ammonium persulfate dissolved in 80 parts of ion-exchanged water and the monomer placed in the pressure-resistant dropping tank were mixed. Drop it over 3 hours at the same temperature,
The reaction was completed by holding it for another 3 hours.

The product thus obtained has a nonvolatile content of 5
The emulsion polymer was 0% and had a pH of 1.6.
After cooling to room temperature, the pH of the reaction mixture was adjusted to 7.5 with 14% aqueous ammonia, while 8 parts of hydrazine was further added, and finally, the non-volatile content was adjusted to 45 with ion-exchanged water. %, Tg is 0 ° C, softening point is 70 ° C
And an aqueous resin dispersion I having a particle size of 0.08 μm
Got

Reference Examples 2 to 10 In the same manner as in Reference Example 1 except that the types and amounts of various monomers and various emulsifiers shown in Table 1 were changed. Aqueous resin dispersions II, III, IV, V and VI (above, aqueous resin dispersion for the present invention) and VII, VIII, IX, X and XI (above, aqueous resin dispersion for control) were obtained, respectively. . The characteristic values of these various aqueous resin dispersions are summarized in the same table.

[0066]

[Table 1]

[0067]

[Table 2]

[0068]

[Table 3]

[0069]

[Table 4]

[0070]

[Table 5]

[0071]

[Table 6]

[0072]

[Table 7]

[0073]

[Table 8]

[0074]

[Table 9]

Examples 1 to 6 and Comparative Examples 1 to 5 Using the respective aqueous resin dispersions obtained in Reference Examples 1 to 11 and blending according to the coating formulations A and B as shown below, each was at room temperature. A white or black glossy paint for drying was prepared.

Table 2 shows the types and amounts of the various components for the preparation of these fluororesin water-based paints.

[Coating Formulation A] (White gloss coating for room temperature drying) Water 7.84 parts 25% ammonia water 0.15 parts “Neugen EA-120” 0.33 parts [Daiichi Kogyo Seiyaku Co., Ltd.] Wetting agent] "Tamol 731" (25% aqueous solution) 1.34 parts (Dispersant manufactured by Rohm and Haas Company, USA) Ethylene glycol 7.46 parts "Taipec R-930" 41.00 parts [Ishihara Sangyo ( Manufactured by Titanium dioxide] "Bestside FX" 0.22 parts [Dainippon Ink and Chemicals, Inc. preservative] "Nopco 8034" 0.30 parts [San Nopco's antifoaming agent] ]

Then, the above components were dispersed in a sand grinder, and 7.46 parts of "Cellosize QP-4400" (3% aqueous solution) and (thickener manufactured by UCC, USA) aqueous resin dispersion Add 100.00 parts of body (solid content = 45%), and add butyl carbitol acetate (film forming aid).
Was added in an amount such that the MFT (minimum film forming temperature) was 0 ° C., diluted with water to a nonvolatile content of the coating of 50%, and uniformly stirred with a stirrer.

[Coating Mixture B] (Black glossy coating for room temperature drying) Aqueous resin dispersion (solid content = 45%) 100.00 parts "Disperse Color SD-9020" 0.50 part [Dainippon Ink Co., Ltd.] Carbon dispersion pigment manufactured by Kagaku Kogyo Co., Ltd.] Nopco 8034L 0.01 part [Defoamer manufactured by San Nopco] 0.20 parts Bestside FX 0.23 parts Neugen EA-120 0.33 parts , Stir evenly with a stirrer, add butyl carbitol acetate (film forming aid) in an amount such that the MFT becomes 0 ° C., and dilute with water to a nonvolatile content of the coating of 40%, Stir evenly with a stirrer.

[0080]

[Table 10]

<< Footnote of Table 2 >> Abbreviation of "formyl group-containing monomer" ... "Formyl group-containing monomer used in aqueous resin dispersion"

[0082]

[Table 11]

[0083]

[Table 12]

[0084]

[Table 13]

Examples 7-12 and Comparative Examples 6-1
Each of the aqueous coating compositions (that is, the aqueous coating compositions) obtained in Examples 1 to 6 and Comparative Examples 1 to 5 was applied to various base materials to obtain various coated articles.

Each coated article was evaluated for various properties of the coating film. The results are shown separately in Table 3 (white glossy paint) and Table 4 (black glossy paint).

[Substrate] Substrate a: Slate plate Substrate b: Polished soft steel plate

[Coating Method] Each of the base materials a and b was coated with various water-based coating compositions (water-based coating materials) individually at room temperature in an amount of 120 g / m ² .
After being dried at room temperature for 1 day, it was further coated with an amount of 80 g / m ^{2 and} dried at room temperature for 7 days to obtain various coated articles.

Each coated article was then subjected to various tests as described below.

[Film coating test procedure] Boiling resistance: Visually judge the change state of the coated surface after being immersed in boiling water for 2 hours. O: No change. … Blanching and blister etc. occur and it is completely defective

Solvent resistance: The change of the coated surface after rubbing the coated surface 20 times (20 reciprocations) at 3 Kg / cm ² using absorbent cotton impregnated with toluene Visually judge the condition ○ ……… No change △ ……… Slightly dissolved × ………… Completely dissolved

Accelerated weather resistance: Measured with a sunshine weather meter, gloss retention before and after the accelerated test for 3,000 hours was measured. …… Less than 70%

[0093]

[Table 14]

[0094]

[Table 15]

[0095]

[Table 16]

[0096]

[Table 17]

[0097]

[Table 18]

[0098]

[Table 19]

[0099]

[Table 20]

[0100]

[Table 21]

[0101]

As described above, the room temperature-curable fluororesin water-based coating composition of the present invention has not only weather resistance but also a strong film-forming state due to interparticle cross-linking. The present invention provides an extremely highly practical water-based coating material and an article to be coated which can maintain solvent resistance and the like for a long period of time.

Claims (8)

[Claims] 1. An aqueous resin dispersion obtained by copolymerizing a fluoroolefin, crotonaldehyde and / or alkenal, and other copolymerizable monomers, and at least hydrazine and / or at least one molecule. A room-temperature-curable fluororesin water-based coating composition comprising a compound having two hydrazyl groups as an essential component and, if necessary, pigments. 2. An aqueous resin dispersion obtained by copolymerizing a fluoroolefin, crotonaldehyde and / or alkenal, a crosslinkable monomer and other copolymerizable monomers, and hydrazine. And / or a compound having at least two hydrazyl groups in one molecule as an essential component and, if necessary, also pigments, a room temperature curable fluororesin aqueous coating composition Stuff. 3. The fluoroolefin is copolymerized in an amount of 10 to 80% by weight based on the solid content of the room temperature-curable fluorinated resinous resin dispersion. Or the water-based coating composition according to item 2. 4. The aqueous coating composition according to claim 1, wherein the fluoroolefin is at least one selected from the group consisting of chlorotrifluoroethylene, vinylidene fluoride and hexafluoropropylene. . 5. The crotonaldehyde and / or alkenal is contained in an amount of 0.01 to 20% by weight based on the solid content of the room temperature-curable fluororesin aqueous resin dispersion.
The copolymer is copolymerized within the following range.
The water-based coating composition according to 1. 6. The room temperature-curable fluororesin aqueous resin dispersion, wherein the hydrazine and / or the amino group derived from the hydrazyl group in the compound having at least two hydrazyl groups in one molecule is contained in the room temperature-curable fluororesin aqueous resin dispersion. The aqueous coating composition according to claim 1 or 2, which is contained in an amount of 0.01 to 5 mol per mol of the formyl group. 7. The crosslinkable monomers are added to the solid content of the room temperature curable fluororesin aqueous resin dispersion,
The aqueous coating composition according to claim 2, which is copolymerized in the range of 0.1 to 2% by weight. 8. An article coated with the aqueous coating composition according to any one of claims 1 to 7.