JP3369785B2 - Water-based fluororesin paint - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous fluororesin paint which can be cured at room temperature.

[0002]

2. Description of the Related Art Conventionally, fluororesin paints utilizing the excellent weather resistance of fluorocopolymers have been industrialized. In particular, solvent-soluble fluorine-based copolymers having a curing site have been synthesized (for example, JP-A-57-34107 and JP-A-6-34107).
1-57609), and is widely applied as a weather-resistant paint in the fields of construction, automobiles, chemical industry and the like. The main component of these paint resins is a fluorine-based raw material such as chlorotrifluoroethylene, and the solubility of the resin is increased by using a hydrocarbon-based monomer such as vinyl ester or vinyl ether as a copolymerization component. . In addition, water-based, powder, and high-solid type paints that place importance on the environment and reduce the emission of organic solvents are being actively researched and developed and are being put to practical use.

Of these, it is difficult to impart a cross-linking site to an aqueous fluororesin coating, and so far, a so-called lacquer type water-based coating has been used in many cases in which a high molecular weight emulsion produced by emulsion polymerization is applied as it is. For this reason, self-emulsifying polyisocyanates have been developed as a curing agent for cross-linking water-based paints, but the pot life of the paint is considered because the isocyanate group easily reacts with water, which is the dispersion medium, to deactivate the curing action. Therefore, it is necessary to disperse the curing agent in water immediately before coating. However,
The conventional self-emulsifying polyisocyanates have a drawback that it is difficult to disperse the curing agent component uniformly and finely, especially at the time of on-site construction, because the water dispersibility is insufficient.

[0004]

In a room temperature curable fluororesin water-based emulsion paint, it is difficult to disperse the curing agent in the fluororesin emulsion, so that the water resistance of the coating film originally formed from the fluororesin paint is high. There is a problem in that excellent physical properties such as properties, weather resistance, and stain resistance cannot be sufficiently expressed.

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention have studied in detail the dispersibility of a curing agent compounded in a paint comprising an aqueous emulsion of a fluororesin in water. It was found that the self-emulsifying polyisocyanate used for the purpose of (1) showed a certain dispersibility but was not sufficient. Therefore, as a result of further research to improve the dispersibility of this self-emulsifying polyisocyanate in water, it is possible to achieve the object by using a compound containing an oxyethylene unit and an alkoxysilyl group in the molecule. They have found what they can do and completed the present invention.

That is, the present invention provides at least 30 to 65 mol% of a fluoroolefin, 14 to 70 mol% of a copolymerizable vinyl compound, a hydroxy group-containing compound and / or a carboxyl group-containing polymerizable compound 1 to 30.
Fluorine-based copolymer (A) obtained by copolymerizing mol%
To the water-based emulsion (I), the self-emulsifying polyisocyanate (B) and the compound (C) containing at least an oxyethylene unit and an alkoxysilyl group in the molecule are mixed at a weight ratio (C) / (B) of 0. It is an aqueous fluororesin coating material containing a curing agent (II) mixed so that the curing agent (II) is 1 to 100 parts by weight of the fluorocopolymer (A). It is an aqueous fluororesin coating compounded with 50 parts by weight.

The present invention will be described in detail below. In the present specification, "part" means "part by weight". Examples of the fluoroolefin used in the fluorine-based copolymer (A) according to the present invention include chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, hexafluoroisobutene, vinylidene fluoride, trifluoroethylene, vinyl fluoride and the like. The composition ratio thereof is 30 to 65 mol% of all monomers. When the content of these fluoroolefins is less than 30 mol%, the weather resistance of the coating film decreases, and when it exceeds 65 mol%, the water dispersibility of the fluorocopolymer (A) decreases, which is not preferable.

The copolymerizable vinyl compound used in the present invention is not particularly limited, but vinyl ester, vinyl ether, allyl ether and the like are preferably adopted. As the vinyl ester, a polymerizable ester compound having a carbonyl group in the molecule, for example,
Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl caproate, vinyl caprylate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl versatate 9
Versatic vinyl octoate, vinyl benzoate and the like can be mentioned. Examples of vinyl ethers include methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl ether, and the like. As the allyl ether, for example, ethyl allyl ether, butyl allyl ether, benzyl allyl ether, allyl glycidyl ether, cyclohexyl allyl ether, allyl acetoacetate and the like are used. In addition, polyethylene glycol for the purpose of improving the emulsifying property,
Vinyl ether or allyl ether having a polyalkylene glycol chain such as polypropylene glycol can also be used. Furthermore, alkoxyvinylsilane compounds such as trimethoxyvinylsilane, triethoxyvinylsilane, and diethoxymethoxyvinylsilane can also be used. Further, olefins such as ethylene, propylene, vinyl chloride and the like can be appropriately added for modifying the fluorine-based copolymer (A). The composition ratio of these monomers is 14 to 70 mol% of all the monomers. When it is less than 14 mol%, the polymerization reactivity is lowered, and when it exceeds 70 mol%, the fluorine content of the fluorine-based copolymer (A) is substantially lowered, which is not preferable.

In the present invention, the hydroxy group-containing polymerizable compound is used for the purpose of introducing a crosslinking site. The hydroxy group-containing polymerizable compound used in the present invention, an allyl ether having a hydroxy group in the molecule,
Examples thereof include vinyl ether and crotonic acid modified compounds. Specifically, for example, ethylene glycol monoallyl ether, propylene glycol monoallyl ether,
Diethylene glycol monoallyl ether, polyethylene glycol monoallyl ether, alkylene glycol monoallyl ethers such as hydroxybutyl allyl ether, hydroxymethyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, hydroxypentyl vinyl ether, hydroxyalkyl vinyl ethers such as hydroxyhexyl vinyl ether, Polyethylene glycol monovinyl ethers such as diethylene glycol monovinyl ether and crotonic acid modified compounds such as hydroxyethyl crotonic acid are preferably used. Further, glycerin monoallyl ether having two hydroxy groups in the molecule, ε-caprolactone-modified allyl ether or vinyl ether can also be used.

As the carboxyl group-containing polymerizable compound, any compound containing a carboxyl group and a polymerizable double bond such as vinyl acetic acid, decenoic acid, undecylenic acid, crotonic acid may be used without particular limitation. It is possible. Of these, undecylenic acid can be introduced into the fluorine-based copolymer (A) as a reactive emulsifier, so that it becomes possible to reduce the amount of emulsifier added to the coating material and improve the water resistance and weather resistance of the coating film. It is particularly preferable because it helps. The copolymerization composition ratio of these hydroxy group-containing polymerizable compounds or carboxyl group-containing polymerizable compounds is 1 to 30 mol% of all monomers, and when the composition ratio is less than 1 mol%,
There are few cross-linking sites and the film does not cure sufficiently, resulting in poor weather resistance and water resistance. When it exceeds 30 mol%, the hydrophilicity of the fluorocopolymer (A) increases and the water resistance of the coating film increases. It is not preferable because it decreases.

As the method for polymerizing the fluorocopolymer (A) according to the present invention, a usual radical polymerization method can be adopted in the production thereof, and the polymerization forms thereof include emulsion polymerization, solution polymerization and suspension polymerization. Fluorine-based copolymer (A)
Is particularly preferably emulsion polymerization in which is obtained as an aqueous emulsion.

As the emulsifier used in such emulsion polymerization, an anionic emulsifier or a nonionic emulsifier can be used. Examples of anionic emulsifiers include:
Examples thereof include alkylbenzene sulfonate, alkyl sulfate salt, polyoxyethylene alkylphenol sulfate salt, styrene sulfonate, vinyl sulfate salt and derivatives thereof. Examples of these salts include salts with alkali metal hydroxides and salts with volatile bases such as ammonia or triethylamine. Examples of the nonionic emulsifier include polyoxyethylene alkylphenol ether, polyoxyethylene alkyl ether, polyoxyethylene higher fatty acid ester, ethylene oxide-propylene oxide block copolymer, fluoroalkyl carboxylate and fluoroalkyl sulfate. The amount of these emulsifiers used depends on the composition of the monomers used and the concentration of the monomers in water, but is 0.5 to 10 parts with respect to 100 parts by weight of the total weight of the monomers to be emulsion polymerized. It is preferable to use the above range. If the amount used is less than 0.5 part, the monomer is not sufficiently dispersed in the aqueous phase, and if it exceeds 10 parts, the water resistance and weather resistance of the coating film deteriorate, which is not preferable.

The radical polymerization initiator that can be used in the emulsion polymerization of the fluorocopolymer (A) according to the present invention is not particularly limited as long as it can be used in general emulsion polymerization. An initiator can be applied particularly preferably. Examples of such water-soluble initiators include inorganic peroxides such as hydrogen peroxide, cumene hydroperoxide, benzoyl peroxide, t-butyl hydroperoxide, disuccinic acid peroxide,
Organic peroxides such as diglutaric acid peroxide, ammonium persulfate, potassium persulfate, persulfates such as sodium persulfate, azobisisobutylamidine hydrochloride,
Azo-based initiators such as azobisisobutyronitrile and azobiscyanovaleric acid, or the above initiators and sodium sulfite, sodium thiosulfate, sodium bisulfite, sodium metabisulfite, sodium bithiosulfate, sulfoxylic acid formaldehyde Use a redox initiator composed of a combination of reducing agents such as sodium and reducing sugars, and an initiator system in which a small amount of iron, ferrous salt, silver sulfate, copper sulfate, etc. are coexistent as a metal in these combinations. be able to. The optimum usage of these radical polymerization initiators depends on the type, the monomer concentration in the aqueous emulsion, the polymerization temperature, etc.
It is preferably used in the range of 0.05 to 5 parts per 100 parts of the total monomers. The addition method of these radical polymerization initiators may be batch addition or divided addition.

The water used in the emulsion polymerization may be used in an amount of 50 to 400 parts per 100 parts of the monomer, depending on the monomer composition and the emulsifier concentration.
Of these, the range of 70 to 150 parts is particularly preferable. If it is less than 50 parts, the particle size of the obtained emulsion becomes large,
The storage stability and the touch-drying speed of the coating film decreased,
If the amount exceeds the above range, the solid content concentration of the obtained aqueous emulsion becomes low, which is not preferable. Further, it is possible to appropriately add or remove water to the obtained emulsion polymer to adjust the solid content concentration of the aqueous emulsion.

The temperature of the polymerization step depends on the radical polymerization initiator used, but it is usually 0 to 150 ° C. The water-based emulsion (I) according to the present invention is a varnish of the fluorine-based copolymer (A) obtained by suspension polymerization in addition to the emulsion polymerization described above and by solution polymerization using a general organic solvent. Can also be obtained by the method of dispersing in water. The method for dispersing in water is not particularly limited, but for example, there is a method in which a non-water-soluble organic solvent solution of the fluorocopolymer (A) is added to water in the presence or absence of an emulsifier to disperse it. The water-insoluble organic solvent at this time is not particularly limited as long as it is water-insoluble and is used in ordinary paint thinners, toluene, xylene, butyl acetate, ethyl acetate, propylene glycol methyl acetate, alkyl silicate. And the like are particularly preferably adopted. Here, the alkyl silicate is tetraalkoxysilane or a condensate thereof, and specifically, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-2. Examples thereof include methoxyethoxysilane, tetra-2-ethylhexyloxysilane, and the like or condensates thereof. As the alkyl silicate obtained by condensing such an alkoxysilane after partial hydrolysis, various ones having different degrees of condensation, structures and kinds of alkoxy groups are commercially available. For example, M silicate 51, ethyl silicate 40, ethyl silicate. 45 (for example, product of Tama Chemical Industry Co., Ltd.) and the like. It is also possible to use an alkyl silicate obtained by further hydrolyzing these and concentrating the silica content to 57% by weight. However, those that are partially hydrolyzed and have not proceeded with condensation have an affinity for or dissolve in water and are not preferable because they are difficult to emulsify.

The solid content concentration of the aqueous emulsion (I) according to the present invention is preferably 10 to 70% by weight. When the solid content concentration is less than 10% by weight, the capacity of the coating material increases, which is inconvenient for storage and transportation, and the drying time of the coating film becomes long, while when it exceeds 70% by weight, the water-based emulsion (I) is used. Has a high viscosity and the resulting water-based fluororesin coating composition has poor coating properties, which is not preferable.

The curing agent (II) used in the present invention comprises a self-emulsifying polyisocyanate (B) and a compound (C) containing at least an oxyethylene unit and an alkoxysilyl group in the molecule in a weight ratio (C) / It can be prepared by uniformly mixing (B) in the range of 0.01 to 1. If this weight ratio is less than 0.01, the self-emulsifying polyisocyanate (B) has insufficient water dispersibility, resulting in uneven cross-linking of the coating film, resulting in poor water resistance, weather resistance and stain resistance. If it exceeds 1, the content of alkoxysilyl groups is large and cracks are likely to occur in the process of curing the coating film, which is not preferable.

The self-emulsifying polyisocyanate (B) used in the present invention is hexamethylene diisocyanate,
Tolylene diisocyanate, xylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenyl methane diisocyanate and the like as a skeleton, a hydrophilic group, for example, having an oxyethylene group Any material can be used without particular limitation. For example, Sumitomo Bayer Urethane Bayhijure TPLS-2032 having an oxyethylene group, Nippon Polyurethane DC-39.
00, DC-3901, DC-3712, etc. correspond to this.

Further, the compound (C) having at least an oxyethylene unit and an alkoxysilyl group in the molecule used in the present invention has 1 to 20 oxyethylene repeating units.
It is preferably in the range of. When the compound (C) does not have an oxyethylene unit, self-emulsification of the compound (C) becomes difficult, and when the number of oxyethylene repeating units exceeds 20, the compound (C) is dissolved in water, which is not preferable. Also,
As the alkoxysilyl group in the molecule of the compound (C),
For example, methyldiethoxysilyl group, triethoxysilyl group, methyldimethoxysilyl group, trimethoxysilyl group, tripropoxysilyl group, triisopropoxysilyl group, tris (β-methoxyethoxy) silyl group, tributoxysilyl group, tri ( A 2-methoxyethyl) silyl group, a tri (2-ethylhexyloxy) silyl group or the like can be adopted.

The method for producing such a compound (C) is not particularly limited, but can be obtained, for example, by reacting a compound having a reactive group and an alkoxysilyl group with a polyoxyethylene derivative having a reactive group. . As such a reaction example, a coupling reaction based on a reaction between a hydroxy group and an isocyanate group, an epoxy group or a halogeno group and an amino group, which each molecule has, can be used. Also, to give another example, both ends,
Alternatively, a reaction in which polyoxyethylene having a hydroxy group at one end is subjected to vinylation of the terminal portion with a metal alcoholate, allyl halide, etc., silylation with trichlorosilane, and then alkoxysilylation with a metal alcoholate can be exemplified. Of these, the reaction of a polyoxyethylene derivative having a reactive group having an active hydrogen such as a hydroxy group, a carboxyl group, an amino group and a mercapto group with a compound having an isocyanate group and an alkoxysilyl group requires a complicated reaction process. It is particularly preferably used because it is not used. Such compounds include:
For example, the general formula OCN (CH ₂ ) ₃ SiX _n Y _(3-n) (1) (wherein Y is hydrogen or a hydrocarbon group having 1 to 8 carbon atoms, X
Represents an alkoxy group having 1 to 3 carbon atoms, and n represents an integer of 1 to 3. ) And alkoxysilanes having an isocyanate group. Specifically, for example,
γ-isocyanatopropylmethyldiethoxysilane,
γ-isocyanatopropyltriethoxysilane, γ-
Isocyanatopropylmethyldimethoxysilane, γ-
Isocyanatopropyltrimethoxysilane and the like are preferably used. Such a compound is a commercially available product, Y-518 having a trimethoxysilyl group manufactured by Nippon Unicar
7 and Y-9030 having a triethoxysilyl group and the like, which can be arbitrarily selected and used. Further, as the polyoxyethylene derivative to be reacted with these compounds,
Compounds containing at least one hydroxy group reactive with an oxyethylene unit in the molecule are mentioned as preferable ones, and among them, the number of repeating units of oxyethylene is 1-2.
Compounds in the 0 range are preferred. Examples of such compounds include oxyethylene monomers and polyoxyethylene, oxyethylene alkylaryl ethers and polyoxyethylene alkylaryl ethers,
Oxyethylene alkyl ether and polyoxyethylene alkyl ether, oxyethylene alkyl ester and polyoxyethylene alkyl ester, oxyethylene alkylamine and polyoxyethylene alkylamine, oxyethylene aryl ether and polyoxyethylene aryl ether, oxyethylene aryl ester and poly Examples include oxyethylene aryl ester, sorbitan fatty acid ester, polyhydric alcohol such as glycerin modified with oxyethylene, and oxyethylene-modified silicone.Even if these oxyalkylene chains are copolymerized with other polyoxyethylene chains. Good. Specific examples of these oxyalkylenes include oxypropylene and oxytetramethylene, and the copolymerization may be random copolymerization or block copolymerization.

It is presumed that the compound (C) according to the present invention has self-emulsifying property due to hydrophilicity due to polyoxyethylene site and hydrophobic amphipathicity due to alkoxysilyl site. That is, the polyoxyethylene part of the compound (C) improves the affinity between the compound (C) and the self-emulsifying polyisocyanate (B) in the curing agent (II), and the self-emulsifying polyisocyanate (B) It is considered that the self-emulsifying property of is stabilized. Further, the hydrolyzability of the alkoxysilyl moiety of the compound (C) and the crosslinkability after hydrolysis are due to the water resistance of the coating film,
It is also considered to contribute to the improvement of stain resistance.

As the curing agent (II) of the present invention, if the self-emulsifying polyisocyanate (B) and the compound (C) described above are essential components, other compounds can be added as appropriate. Specifically, general polyisocyanates for improving the crosslinkability, organic solvents and oligomers for reducing the viscosity of the curing agent, and for assisting the self-emulsifying property of the self-emulsifying polyisocyanate (B) Various emulsifiers,
Alkyl silicates for improving hardness and stain resistance, water-soluble amine catalysts for promoting crosslinking, etc.,
It is preferable to add within 30% or less of the curing agent (II). Such a water-soluble amine catalyst may be added in advance to the water-based emulsion (I) and the curing agent (II) or may be added when the two are mixed, and the fluorine-based copolymer (in the water-based emulsion (I) ( A) It is preferable to add 3 parts or less to 100 parts. Such an amine-based water-soluble catalyst has a low reaction catalytic action between the isocyanate group of the curing agent and water, and has a compound (C)
Those which efficiently cause the hydrolysis of the alkoxysilyl group are preferably used. Specific examples of such amine-based water-soluble catalysts include N, N, N ′, N′-tetramethyldiaminoethane, N, N, N ′, N′-tetramethyldiaminohexane, N, N, N ′, N, N, N ', N'-tetramethyldiamino compounds such as N'-tetramethyldiaminobutane, N-methylmorpholine, N
-Ethylmorpholine, N-methylpiperazine, N, N '
-Dimethylpiperazine, N, N'-dimethylbenzylamine, N, N'-dimethyldodecylamine and the like can be mentioned. Among them, N, N, N ',
N'-tetramethyldiamino compounds are particularly suitable.

The aqueous fluororesin coating composition of the present invention comprises an aqueous emulsion (I) and a curing agent (II). The mixing ratio of these is 100 parts of the fluorocopolymer (A) of the aqueous emulsion (I). On the other hand, the curing agent (II) can be used in the range of 1 to 50 parts. If it is less than 1 part, crosslinking will be insufficient and water resistance and stain resistance will not be exhibited, and if it exceeds 50 parts, the weather resistance will decrease, such being undesirable.

As the compounding formulation of the aqueous fluororesin coating material of the present invention, a method of stirring and mixing a curing agent (II) previously emulsified in water with an aqueous emulsion (I) consisting of an aqueous emulsion, an aqueous emulsion (I )
For example, a method of directly mixing the curing agent (II) with stirring can be mentioned.

The water-based emulsion (I) of the present invention can be used as it is as a room temperature-curable aqueous fluororesin paint, but if necessary, various additives such as a thickener and a film-forming aid are added to the paint. Agent, pigment dispersant, dispersion aid,
A pigment, a defoaming agent, an anti-settling agent, a leveling agent, an ultraviolet absorber, a light stabilizer, an anticorrosive agent, an antifungal agent and the like may be added in the particles of the emulsion or in water without particular limitation.

The present invention will be specifically described below with reference to examples.

[0027]

【Example】

[Synthesis Examples 1 to 5] 71 g (27 mol%) of vinyl butyrate, 43 g (10 mol%) of versatic vinyl octanoate, 30 g (10 mol%) of hydroxybutyl allyl ether, 13 g (3 mol%) of undecylenic acid and a nonionic emulsifier. New
col504 (manufactured by Nippon Emulsifier Co., Ltd.), a mixed solution of monomers, 6 g of sodium carbonate decahydrate dissolved in 30 g of ion-exchanged water as an acid acceptor solution, and 0.5 g of ammonium persulfate in 30 g of ion-exchanged water. Prepare the aqueous solution of the polymerization initiator dissolved in each, and the content of 2 with a magnetic stirrer.
Into a liter SUS autoclave, mix the monomer mixture,
Acid acceptor aqueous solution, polymerization initiator aqueous solution, ion-exchanged water 680
g were sequentially charged, and the mixture was stirred and mixed so as to be uniform, and deaeration and substitution with nitrogen gas were repeated 3 times, and then 134 g (50 mol%) of chlorotrifluoroethylene was charged and the mixture was added at 50 ° C. for 24 hours.
Polymerization was performed for a time (Synthesis example 1).

Similarly, various monomers and compositions shown in Table 1 were polymerized to obtain a fluorinated copolymer (A) (Synthesis Examples 2 to 5). In either case, after the completion of the polymerization, the contents were taken out, concentrated so that the solid content concentration became 50% by weight, adjusted to PH8 with 28% ammonia water, and the fluorine-based copolymer (A) was obtained. To obtain an aqueous emulsion (I).

[0029]

[Table 1]

<Evaluation method> ・ Storage stability Stability after 1 month at 50 ° C.

◯: No change, ×: Particle sedimentation ・ Mechanical stability Stability after stirring at 5000 rpm for 5 minutes.

◯: No change, ×: Increase in particle size [Synthesis Examples 6 to 8] PEG-200 (manufactured by Sanyo Kasei Co., Ltd .: hydroxy terminal) was placed in a SUS autoclave with a magnetic stirrer and an internal volume of 2 liters. Average molecular weight of 200
Polyoxyethylene) 400 g (33 mol%), Y-
9030 (manufactured by Nippon Unicar Co., Ltd .: OCN- (CH ₂ ) ₃
988 g (67 mol%) of —Si— (OEt) ₃ ) was charged, and deaeration and substitution with nitrogen gas was repeated 3 times, and then the reaction was carried out at 100 ° C. for 5 hours (Synthesis example 6). Confirmation of the reaction product by ¹ H-NMR measurement for the compound obtained after the reaction,
And the calculation of the reaction yield was performed. As a result, 4.2pp
A unique peak indicating that a urethane bond was formed by the reaction was observed at m and 5.1 ppm, and the reaction yield was calculated to be 93% from the integrated ratio of these peaks.

Further, the compositions shown in Table 2 were similarly reacted (Synthesis Examples 7 to 8). In each case, xylene used as a solvent was removed by vacuum distillation after the reaction was completed.

[0034]

[Table 2]

Formulation Examples 1 to 5 Baihydur TPLS-2032 manufactured by Sumitomo Bayer Urethane having an oxyethylene group and an isocyanate group as the self-emulsifying polyisocyanate (B) and the compound obtained in Synthesis Example 6 as the compound (C) ( C) /
(B) was mixed so as to be 0.33 (weight ratio) to obtain a curing agent (II) (Formulation Example 1). Similarly, the self-emulsifying polyisocyanate (B) and the compound (C) were blended in the composition shown in Table 3 to obtain a curing agent (II) (blending example 2).
5).

[0036]

[Table 3]

[Example 1] To the aqueous emulsion (I) obtained in Synthesis Example 1, 24 parts of the curing agent (II) of Formulation Example 1 was added to 100 parts of the fluorocopolymer (A) to obtain a uniform mixture. The mixture was stirred and mixed so as to obtain a different emulsion to obtain an aqueous fluororesin coating material.

The obtained aqueous fluororesin paint was applied to 150 × 7.
It was spray-coated on a 0 × 2 mm aluminum plate and cured at room temperature for 3 days. The film thickness of the obtained coating film was 50 microns. The coating film was subjected to gloss measurement, rubbing test, water resistance test, stain resistance exposure test, carbon stain resistance test, and accelerated weather resistance test. The results are shown in Table 4.

[Examples 2 to 4] As in Example 1, Table 3
The curing agents (II) of formulation examples 1 to 3 and the aqueous emulsions (I) of synthesis examples 1 to 5 shown in Table 1 were stirred and mixed. Then, 0.5 part of N, N, N ′, N′-tetramethyldiaminohexane as an amine catalyst was added to obtain an aqueous fluororesin coating material. Hereinafter, a coating film was similarly prepared by spray coating, and gloss measurement, rubbing test, water resistance test, stain resistance exposure test, carbon stain resistance test, and accelerated weathering test were performed. The results are shown in Table 4.

[Comparative Example 1] The aqueous fluororesin coating material comprising the aqueous emulsion (I) obtained in Synthesis Example 5 was spray coated in the same manner as in Example 1 to prepare a coating film. The coating film was subjected to gloss measurement, rubbing test, water resistance test, stain resistance exposure test, carbon stain resistance test, and accelerated weather resistance test. The results are shown in Table 4.

[Comparative Example 2] In the aqueous emulsion (I) obtained in Synthesis Example 1, 100 parts of the fluorine-based copolymer (A) was added to the curing agent (II) of Formulation Example 5 (Baihydur TPLS).
-2032) 18 parts were mixed in the same manner as in Example 1, and a coating film was prepared by spray coating in the same manner as in Example 1 to evaluate the performance of the coating film. The results are shown in Table 4.

Comparative Example 3 42 parts of the curing agent (II) prepared in Formulation Example 4 was added to 100 parts of the fluorocopolymer (A) in the aqueous emulsion (I) obtained in Synthesis Example 2. 1
The mixture was mixed in the same manner as in Example 1, and a coating film was prepared by spray coating in the same manner as in Example 1 to evaluate the performance of the coating film. The results are shown in Table 4.

Comparative Example 1 is an example in which the fluorine-based copolymer (A) does not contain a hydroxy group-containing polymerizable compound or a carboxyl group-containing polymerizable compound as a monomer, and Comparative Example 2 is a curing agent (II). Examples containing no compound (C), Comparative Example 3 in which the weight ratio of (C) / (B) exceeded 1, and Comparative Example 4 in which the compound (C) was used as a curing agent (II) in a fluorine-based copolymer. This is an example in which 50 parts or more are mixed with 100 parts of the combined (A).

[0044]

[Table 4]

<Evaluation Method>-(II) was directly added to the dispersibility (I), and then the dispersibility in the aqueous coating composition was stirred with a stirrer for 10 seconds and visually observed.

○: uniform emulsion, Δ: slightly large particles of (II) were found, ×: particles of (II) remained and precipitated. Gloss measurement: Measured by a 60-degree specular gloss test. unit%.・ Rubbing test A rubbing tester using gauze moistened with xylene (surface change after 100 reciprocations is evaluated in 3 levels).

◯: No change, Δ: Scratches or whitening, ×:
Swelling, dissolution and water resistance test The coating film after curing for 3 days is immersed in water for 2 weeks, and the coating film abnormality such as peeling and blister is observed.

○: No change, △: Slight blisters, ×: Blister and peeling occur ・ Staining resistance exposure test Bend the coated plate at 135 ° in the center of the long side, and the upper part is 45 ° to the ground, The lower part was installed so as to form an angle of 90 degrees and exposed, and rain streaks generated on the lower coated surface were observed. Kawagoe is exposed for 6 months.

○: No rain streak was generated, △: Light rain streak was generated, ×: Thick rain streak was generated ・ Carbon stain resistance 3% solution of carbon / kerosene was dropped on the coating film and saturated steam pressure at 20 ° C was applied. It was dried for 1 day at 40 ° C. for 2 days, and the detergency in water and the fusiability were observed using an ultrasonic cleaner.

○: Almost no traces can be wiped off, Δ: Traces remain thin, and can be wiped. ×: Accurate weather resistance test Accelerated weathering test Acceleration test with 4000 hours of sunshine weatherometer (60 before and after the test) Gloss retention rate).

[0051]

The water-based fluororesin coating material of the present invention has a good dispersibility of the curing agent in the water-based emulsion made of a fluororesin, so that a uniform film can be obtained, and the water resistance and stain resistance inherent in the fluororesin, It is possible to obtain various properties such as weather resistance, and in addition, since it is easy to mix and disperse the main coating material and the curing agent, there is a remarkable effect that they can be easily prepared at the painting site.

Front Page Continuation (72) Inventor Kentaro Tsutsumi 2805 Imafuku Nakadai, Kawagoe-shi, Saitama Central Chemical Co., Ltd. (56) References JP-A-6-322313 (JP, A) JP-A-7-113005 (JP, A) JP 7-82520 (JP, A) JP 5-179191 (JP, A) JP 6-172451 (JP, A) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) C09D 175/04 C09D 5/00 C09D 127/12

Claims (4)

(57) [Claims] 1. At least a fluoroolefin of 30 to 65.
Fluorine-based copolymer obtained by copolymerizing mol%, copolymerizable vinyl compound 14 to 70 mol%, hydroxy group-containing compound and / or carboxyl group-containing polymerizable compound 1 to 30 mol% ( The weight ratio (C) / (B) of the self-emulsifying polyisocyanate (B) and the compound (C) containing at least an oxyethylene unit and an alkoxysilyl group in the molecule to the aqueous emulsion (I) of A) is Hardening agent (II) obtained by mixing so as to be 0.01 to 1.
Is a water-based fluororesin coating composition containing 100 parts by weight of the fluorocopolymer (A) and 1 part of the curing agent (II).
Aqueous fluororesin paint containing 50 parts by weight. 2. The fluorocopolymer (A) comprises chlorotrifluoroethylene as the fluoroolefin, vinyl esters as the vinyl compound, and a hydroxy group-containing allyl compound as the hydroxy group-containing polymerizable compound. The fluorine-based copolymer (A) obtained by the above process.
The water-based fluororesin paint described. 3. The aqueous fluororesin coating composition according to claim 1, wherein the fluorocopolymer (A) is a fluorocopolymer (A) obtained by copolymerizing undecylenic acid as a carboxyl group-containing polymerizable compound. 4. The aqueous fluororesin coating composition according to claim 1, wherein the aqueous emulsion (I) is an aqueous emulsion (I) of the fluorocopolymer (A) obtained by emulsion polymerization.