JP3355639B2 - Aqueous curable resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel and useful aqueous curable resin composition. More specifically, it is mainly composed of an aqueous dispersion of a fluororesin having a curable site, and in particular, can be cured at a low temperature, and has excellent durability such as weather resistance, chemical resistance, and alkali resistance. The present invention relates to an extremely practical and curable aqueous curable resin composition which is excellent and has excellent stain resistance and the like.

[0002]

2. Description of the Related Art In recent years, as a coating agent for articles exposed to the outdoors, such as building exterior materials and industrial materials, those which have excellent durability and are maintenance-free for a long period of time are required. Have been.

Under these circumstances, fluoroolefin copolymers are well known as binders having high weather resistance and high chemical resistance, and those in the form of an organic solvent solution have already been used. It is commercially available.

[0004] However, from a place containing a large amount of an organic solvent, there is a problem of fire danger, harmfulness or air pollution, and an aqueous fluoroolefin-based binder has been required.

[0005] So far, tetrafluoroethylene,
Aqueous dispersions of polymers of fluoroolefins such as vinylidene fluoride or hexafluoropropylene (fluoroolefin polymers) have been proposed.

However, these polymer dispersions require baking at a high temperature during the film formation process. For example, even in the invention described in JP-A-57-38845, in the case of vinylidene fluoride and hexafluoropropylene copolymer, 180-230
Baking at a temperature in the range of ° C. is required.

[0007] Such high-temperature baking is, of course, impossible in the field of ordinary dry paints to be painted on site, and economical baking is also possible in factory line painting in which heating and drying are mainly performed. Can be said to be disadvantageous.

On the other hand, the invention described in Japanese Patent Application Laid-Open No. 61-26167 discloses 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. We are making disclosure about physical technology,
According to this, the film forming property is greatly improved.

[0009] However, it is important that the coating agent for the object to be exposed outdoors is not only durable, but also does not cause deterioration in appearance due to contamination of the coating film due to medium smoke or the like. .

Generally, in order to obtain film forming properties at a low temperature,
The glass transition temperature and the minimum film forming temperature of the resin must be lowered, which results in a softened coating film and, consequently, a lack of stain resistance and the like.

Therefore, it is possible to form a film at a low temperature,
In addition, the emergence of water-based coating agents that fully satisfies both the so-called coating durability and stain resistance, such as weather resistance, chemical resistance, water resistance, boiling water resistance, and alkali resistance. However, there is an urgent need.

[0012]

As described above, as far as the prior art is concerned, the essential component is an extremely practical aqueous dispersion of a fluororesin which has both such durability and stain resistance. In fact, it was extremely difficult to obtain an aqueous curable resin composition.

However, the object of the present invention is to form a film at a so-called low temperature, such as at room temperature, and to further improve weather resistance, chemical resistance, water resistance, boiling water resistance and alkali resistance. Another object of the present invention is to provide a water-based fluoroolefin-based coating agent which is excellent in overall durability and stain resistance of a coating film.

[0014]

Means for Solving the Problems Accordingly, the present inventors have:
Directly looking at the advantages and disadvantages of the prior art as described above, as a result of diligent studies, as a main component, using a fluororesin aqueous dispersion as a main component, and a specific water solubility such that this fluororesin can be cured Using a curing agent, a resin composition comprising both of these components as essential components has been found to be able to solve and overcome all of the above-mentioned problems, and complete the present invention. Reached.

That is, the present invention provides an aqueous dispersion (A) of a fluororesin having a curable site (a) and a curable site (a) of the aqueous dispersion (A) of the fluororesin. An aqueous curable resin composition containing, as an essential component, a curing agent (B) having a functional group (b) to be obtained, wherein the curable site (a) is a carboxyl group, and the fluororesin is , Crotonic acid and / or itaconic acid as an essential acid group-containing monomer component, and an aqueous dispersion of the fluororesin (A)
Is at least one member selected from the group consisting of alkylbenzenesulfonates and vinylsulfonates; and / or
Or an aqueous curable resin composition characterized by being an aqueous dispersion obtained by polymerizing a monomer having a curable site (a) in an aqueous medium in the presence of an emulsifier comprising a polyoxyethylene alkyl ether. What you want to do.

[0016]

The aqueous dispersion of a fluororesin having a curable site (A) is a fluororesin having a functional group capable of mutually reacting with a functional group contained in a water-soluble curing agent (B) described later. It refers to an aqueous dispersion.

[0017] Only typical representative combinations of functional groups which can react with each other are exemplified.
(1) a carboxyl group and an epoxy group; and (2) a carboxyl group and a blocked isocyanate group. In addition, a combination of other functional groups can be used as needed. That is, the combination of other functional groups is (3) an epoxy group and an amino group,

(4) an epoxy group and a hydroxyl group,
(5) a hydroxyl group and an amino group; and (6) a hydroxyl group and a blocked isocyanate group.

The carboxyl group of these combinations may be present in the fluororesin aqueous dispersion (A), and the functional group which reacts with the carboxyl group may be contained in the water-soluble curing agent (B). .

That is, the method is such that the monomer having such a carboxyl group is introduced by copolymerizing with the monomers constituting the fluororesin (A).

In this method, a combination of functional groups which reacts easily with water from a place where the medium is water is not suitable.

In the present invention, (1) the monomer having a carboxyl group includes crotonic acid and itaconic acid,
The itaconic acid contains itaconic anhydride.
In addition to these, other acids can be used in combination. Other acids include various carboxyls such as unsaturated group-containing hydroxyalkyl ester monocarboxylic acids such as (meth) acrylic acid, maleic acid, fumaric acid, citraconic acid, maleic anhydride, and adducts with glycols. Examples include a group-containing monomer or a dicarboxylic acid. The purpose of introducing the carboxyl group-containing monomer is not only to use it as a curable site, but also to improve the stability of the aqueous dispersion, and to adhere to the substrate in the final use. In order to improve In addition, as a monomer having a functional group, a functional group other than a carboxyl group, for example, an epoxy group-containing monomer, an amino group-containing monomer, a sulfonic acid group-containing monomer, a hydroxyl group-containing monomer, a blocked isocyanate group Containing monomers can be used in combination.

(2) Examples of the epoxy group-containing monomer include allyl glycidyl ether and glycidyl (meth) acrylate. (3) As the amino group-containing monomer, allylamine,
(Meth) acrylamide, N-methylol (meth) acrylamide, N-alkoxymethylated (meth) acrylamide, N, N-dialkyl (meth) acrylamide,
Various polycarboxylic acid anhydride group-containing monomers such as diacetone acrylamide, N, N-dialkylaminoalkyl (meth) acrylate or maleic anhydride, active hydrogen groups capable of reacting with these, and tertiary amino acids Examples include various tertiary amino group-containing monomers, such as adducts with compounds having a group. (4) Examples of the sulfonic acid group-containing monomer include 2-acrylamido-2-methylpropanesulfonic acid.

(5) Examples of the hydroxyl group-containing monomer include hydroxyl group-containing vinyl ethers such as various hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether.
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth)
Examples thereof include acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, and polyethylene glycol mono (meth) acrylate. (6) Examples of the blocked isocyanate group-containing monomer include a blocked isocyanate alkyl (meth) acrylate.

To obtain the component (A) constituting the present invention,
Monomers having a curable site such as a carboxyl group are contained in all monomer raw materials (the same applies hereinafter) in an amount of 1 to 35% by weight, a fluoroolefin monomer described below in an amount of 30 to 70% by weight, Other monomers may be polymerized within a range not exceeding 50% by weight.

As the other monomer, preferably, various olefins such as ethylene or propylene; or various carboxylic acid vinyl esters such as vinyl acetate or vinyl versatate are suitably used. More preferably, in addition to the above, the use of a crosslinkable monomer or the like for performing intraparticle crosslinking in advance gives good results.

If only typical typical examples of the fluoroolefin constituting the component (A) are exemplified, vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, 1,1,3,3
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 the like.

Of these, preferred are fluoroolefins such as hexafluoropropylene, chlorotrifluoroethylene and vinylidene fluoride. More preferably, chlorotrifluoroethylene should be used from the viewpoint of controlling the reaction during polymerization.

Other monomers include (halogenated) olefins such as ethylene, vinyl chloride, vinylidene chloride, propylene, and butene-1; vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, and vinyl pivalate. , Vinyl caproate, vinyl versatate (vinyl neononanoate, vinyl neodecanoate), vinyl laurate, vinyl stearate, vinyl cyclohexanecarboxylate, vinyl p-t-butylbenzoate, or "Veova" (a vinyl ester manufactured by Shell Inc.) ) And vinyl esters of carboxylic acids.

Of these, the carboxylic acid of the vinyl ester monomer of the carboxylic acid is a linear, branched or cyclic carboxylic acid having 5 or more carbon atoms, which enhances the weather resistance of the film. Therefore, those having 6 or more carbon atoms are more preferable.

That is, a linear, branched or cyclic carboxylic acid vinyl ester monomer having 5 or more carbon atoms has a bulky alkyl group in the molecular structure, so that the finally obtained coating is obtained. This has the effect of improving the water repellency of the film and suppressing the hydrolysis of ester bonds due to, for example, high-temperature water or basic substances.

Therefore, by using the monomer, various properties such as long-term boiling water resistance after film formation and alkali resistance at high temperature can be further satisfied.

[0033]

[0034]

[0035]

In addition to the above, in order to further improve the performance of the final film, the following crosslinkable monomers can be used for the purpose of crosslinking in the particles of the resin dispersion in advance. .

Examples thereof include hexadiene, octadiene, decadiene, tetradecadiene, 2-methyl-
Radical reactivity difference in one molecule such as octadiene, decatriene, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, divinylbenzene, trivinylbenzene, diallyl phthalate, etc. Monomers having two or more polymerizable unsaturated groups having no polymer;

Or vinyltriethoxysilane, trimethoxysilyl vinyl ether, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropylmethyldimethoxysilane, γ
Examples thereof include hydrolyzable silyl group-containing monomers such as-(meth) acryloyloxypropyltriethoxysilane, γ- (meth) acryloyloxypropylmethyldiethoxysilane, and tris (2-methoxyethoxy) vinylsilane.

Among them, one or a mixture of two or more selected from hexadiene, octadiene, decadiene, tetradecadiene, 2-methyl-octadiene and decatriene and / or vinyltriethoxysilane, trimethoxysilylvinylether, γ -(Meth) acryloyloxypropyltrimethoxysilane,
Various types such as [gamma]-(meth) acryloyloxypropylmethyldimethoxysilane, [gamma]-(meth) acryloyloxypropyltriethoxysilane, [gamma]-(meth) acryloyloxypropylmethyldiethoxysilane, and tris (2-methoxyethoxy) vinylsilane Use of a hydrolyzable silyl group-containing monomer is preferable because a stable aqueous dispersion can be obtained.

The purpose of intra-particle crosslinking is to improve durability such as water resistance, alkali resistance and solvent resistance, or to use a polymer having a low glass transition point and a film obtained from the polymer. This is for giving the toughness.

Of course, when these durability are not required, there is no need to use them. The amount of the crosslinkable monomer used is generally less than 3%, preferably less than 2%.

Other examples of usable monomers include 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, perfluorooctyl vinyl ether, perfluorododecyl vinyl ether, 2,2
3,3-tetrafluoropropyl vinyl ether, 2,
2,3,3,4,4,5,5-octafluoropentyl vinyl ether, 2,2,3,3,4,4,5,5
Various types such as 6,6,7,7,8,8,9,9-hexadecafluorononyl vinyl ether, perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, perfluoropropyl vinyl ether, perfluorooctyl vinyl ether or perfluorocyclohexyl vinyl ether (Per) fluoroalkyl vinyl ethers;

A part of the hydrogen atoms has been replaced by fluorine atoms;
Vinyl ethers having a fluoroalkyl group having 3 to 12 carbon atoms; "Biscoat 8F, 8FM, 3F, 3F
M "[fluorinated (meth) acrylic monomer manufactured by Osaka Organic Chemical Co., Ltd.], perfluorocyclohexyl (meth) acrylate, Ni-propyl perfluorooctanesulfonamidoethyl (meth) acrylate, etc. Such as alcohol having (per) fluoroalkyl group and (meth)
(Meth) acrylic esters obtained by an esterification reaction with acrylic acid;

Vinyl esters having various (per) fluoroalkyl groups, such as vinyl trifluoroacetate and diperfluorocyclohexyl fumarate; methyl-, ethyl-, n-propyl-, isopropyl-, n-butyl-, Isoamyl-, n-hexyl-,
alkyl vinyl ethers having various linear or branched alkyl groups, such as n-octyl- or 2-ethylhexyl vinyl ether;

Various (alkyl-substituted) cycloalkyl vinyl ethers having a cyclic alkyl group, such as cyclopentyl vinyl ether, cyclohexyl vinyl ether or methylcyclohexyl vinyl ether; various aralkyl vinyl ethers, such as benzyl vinyl ether or phenethyl vinyl ether;
Sulfonamide group-containing monomers represented by p-styrenesulfonamide, N-methyl-p-styrenesulfonamide, N, N-dimethyl-p-styrenesulfonamide and the like;

Cyano group-containing monomers represented by (meth) acrylonitrile and the like; hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids such as hydroxyalkyl (meth) acrylate and phosphate esters Phosphoric acid ester group-containing monomers obtained by a condensation reaction with phenols;
, Ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
C1 to C8, such as cyclohexyl (meth) acrylate
(Meth) acrylic acid alkyl esters having a linear, branched or cyclic alkyl group;

Styrene, α-methylstyrene, p-te
Various aromatic vinyl compounds such as styrene such as rt-butyl-styrene and p-methylstyrene or derivatives thereof; various (substituted) aromatic nucleus-containing (meth) acrylates such as benzyl (meth) acrylate And diesters of unsaturated dicarboxylic acid and monohydric alcohol such as maleic acid, fumaric acid and itaconic acid.

These monomers are appropriately selected and used in order to adjust the glass transition point, the minimum film-forming temperature, and the like of the finally obtained copolymer. It is used as one kind or a mixture of two or more kinds.

The fluororesin aqueous dispersion (A) having a carboxyl group as a curable site of the present invention can be obtained by polymerizing the above-mentioned monomers in an aqueous medium in the presence of an emulsifier. can get.

The term "emulsifier" used herein is used to stably disperse the above-mentioned various monomers in an aqueous medium and, in the final use mode, to sufficiently exhibit coating film performance. And alkyl (benzene) sulfonate and / or polyoxyethylene alkyl (phenyl) ether can be used.

Examples of the alkyl (benzene) sulfonate include an alkyl sulfonate, an alkylbenzene sulfonate, a derivative thereof, and a substituted product obtained by partially substituting the derivative. As used herein, the salt refers to a salt derived from an alkali metal hydroxide or a salt derived from a volatile base such as ammonia or triethylamine.

The polyoxyethylene alkyl (phenyl) ether includes polyoxyethylene ether,
Examples thereof include polyoxyethylene phenyl ether or derivatives thereof, and substituted products obtained by partially substituting them.

In addition, anionic emulsifiers (including reactive emulsifiers) such as alkyl sulfate salts, polyoxyethylene alkylphenol sulfate salts, styrene sulfonate salts, vinyl sulfate salts and derivatives thereof, polyoxyethylene higher fatty acid esters, ethylene oxide A nonionic emulsifier (including a reactive emulsifier) such as a propylene oxide block copolymer, which can be used in combination with the above emulsifier.

In addition, a fluorine atom-containing emulsifier such as a fluoroalkyl carboxylate represented by perfluorooctanoate or a fluoroalkyl sulfate can be used in combination.

An appropriate amount of these emulsifiers is in the range of 0.5 to 10% by weight, based on the total amount of the monomers, including the anionic and nonionic emulsifiers. Further, in combination with these emulsifiers, a water-soluble oligomer composed of a polycarboxylic acid or a sulfonate, or a so-called water-soluble polymer substance such as polyvinyl alcohol or hydroxyethyl cellulose can be used as a protective colloid.

The polymerization initiator is not particularly limited as long as it is generally used for emulsion polymerization. Among them, particularly typical ones are exemplified, and various water-soluble inorganic peroxides such as hydrogen peroxide; various persulfates such as ammonium persulfate, potassium persulfate and sodium persulfate; Various organic peroxides such as cumene hydroperoxide, benzoyl peroxide, t-butyl hydroperoxide; azobisisobutyronitrile, azobiscyanovaleric acid,
Various azo initiators and the like may be used alone or in combination of two or more.

The amount used is based on the total amount of the monomers.
A range of 0.1 to 2% by weight is appropriate. It should be noted that it is also possible to use a so-called redox polymerization method using a combination of these polymerization initiators and metal ions and a reducing agent,
Of course.

As typical reducing agents, only typical ones are exemplified by sodium bisulfite, sodium metabisulfite, sodium bithiosulfate, sodium hydrosulfate, sodium formaldehyde sulfoxylate or reducing sugar.

Further, only typical representative examples of metal ions include copper sulfate, ferric chloride, ferric sulfate and silver nitrate. In addition, of course, various chain transfer agents can also be used.

The component (A), which is the fluororesin aqueous dispersion, is prepared by separately preparing monomers individually or in an emulsified state in the presence of an aqueous medium, preferably ion-exchanged water and an emulsifier. Drops are dropped into the reaction vessel all at once, dividedly or continuously, and in the presence of the above-mentioned polymerization initiator, at a gauge pressure of about 1 kg / cm2 to 100 kg / cm2, and at about 50 ° C to 150 ° C. At a reaction temperature of
What is necessary is just to polymerize.

In some cases, a higher pressure may be used, or a lower temperature condition may be used. The ratio of total monomer to water should be set so that the final solids content is in the range of 1-60% by weight, preferably 15-55% by weight.

In the emulsion polymerization, a so-called seed polymerization method may be used in which emulsion particles are previously present in an aqueous phase and polymerized in order to grow or control the particle diameter.

As the water in the aqueous medium used here,
Basically, ion-exchanged water is used, but its amount should be 70% by weight or more in the aqueous medium.
Here, the remaining less than 30% by weight may be used in combination with an organic solvent.

The organic solvent mentioned here is not particularly limited, and any organic solvent can be used as long as it is a general-purpose organic solvent. Among them, only typical ones are exemplified. If it is, ketones such as acetone, methyl ethyl ketone and methyl amyl ketone; esters such as ethyl acetate and butyl acetate; aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as hexane and heptane; methanol Alcohol-based solvents such as ethanol, isopropanol and butanol; and halogen-containing organic solvents such as carbon tetrachloride, methylene dichloride and hexafluoroisopropanol, including chlorofluorocarbon-based solvents.

Of these, it is preferable to use an organic solvent having a high affinity for water or a high ability to dissolve olefins and fluoroolefins in an aqueous medium.

That is, particularly recommended organic solvents include various hydrophilic solvents such as acetone, methyl ethyl ketone, methanol, ethanol and isopropanol, and chlorofluorocarbon solvents such as hexafluoroisopropanol.

Here, carbon tetrachloride, heptane and the like sometimes act as a telogen. Therefore, when adjusting the molecular weight, special attention should be paid to the amount used. The polymerization reaction must be carried out under conditions where side reactions due to functional groups and the like do not proceed. For example, the pH may be adjusted using a pH buffer such as disodium phosphate, borax, sodium bicarbonate, or ammonia.

In particular, when a vinyl ether-based monomer is used for copolymerization, a side reaction may be caused in a low pH region or a high pH region.
It should be carried out under zero pH conditions.

In this manner, the fluororesin aqueous dispersion which is the component (A) of the present invention is obtained. The state of the system after the completion of the reaction is such that unreacted gaseous monomer is contained in the emulsion particles. However, only a small portion remains.

Most of the remaining monomers are unreacted fluoroolefins. In order to safely remove the gaseous monomers so as not to destroy the emulsion, the following is required. Perform the operation.

That is, in the case where the obtained dispersion contains an acidic group, all or all of the acidic groups of the acid group-containing monomer converted into the polymer by the basic substance. After neutralizing a part, remove unreacted monomers, or take measures to remove unreacted monomers after adding silicon-based and / or mineral oil-based compounds. good.

Examples of the basic substance include inorganic alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, organic amines such as triethylamine, and ammonia.

Of these, organic amines such as triethylamine and volatile base substances such as ammonia are preferred. As the silicon-based and / or mineral oil-based compounds,
A known and commonly used aqueous antifoaming agent may be used.

As a method for removing unreacted monomers,
At room temperature or at a heating temperature of 100 ° C. or lower, unreacted gaseous monomers may be removed at normal pressure or reduced pressure, or by means such as steam distillation.

At this time, an inert gas such as a nitrogen gas is
Bubbling in the system can also facilitate removal of unreacted gaseous monomers. Obtained in this way,
The fluororesin aqueous dispersion (A) of the present invention generally has a number average molecular weight of 5,000 to 1,000,000 and a weight average molecular weight of not containing a crosslinkable monomer in particles. Is from 10,000 to 3,000,000, and the minimum film forming temperature is in a range from about -10 ° C to + 60 ° C.

Further, the particle diameter is generally about 0.0
A range of 2 to 0.5 microns is appropriate. Next,
The water-soluble curing agent (B) having a functional group capable of mutually reacting with a carboxyl group as a curable site in the component (A) of the present invention refers to a compound capable of reacting with a carboxyl group in one molecule.
It is a water-soluble (polymer) compound having three functional groups.

Particularly typical examples of the compound include (1) an epoxy group-containing compound, and (2) a blocked compound.
It is a compound containing a cyanate group . (1) Examples of the epoxy group-containing compound include various water-soluble epoxy resins such as sorbitol polyglycidyl ether. (2) As a blocked isocyanate group-containing compound
Replaces isocyanatoethyl methacrylate with methyl
Block with chloroketone, and acid group containing
After polymerizing with a monomer, etc., it is obtained by making it water-soluble
Such water-soluble blocked isocyanate group-containing acrylic
Resins and the like can be exemplified. When a curable site other than a carboxyl group is introduced, a water-soluble curing agent having a functional group that reacts with these curable sites can be used. These water-soluble curing agents include the above (1)
Poxy group-containing compound and (2) blocked isocyanate
Other preparative group-containing compound, (3) a carboxyl group-containing compound
Products, (4) an amino group-containing compound, (5) a sulfonic acid group-containing compound, and (6) a hydroxyl group-containing compound .

(3) As a carboxyl group-containing compound
Are water-soluble carboxyl group-containing acrylic resins and polyethers.
Steal resin and the like can be exemplified. (4) Examples of the amino group-containing compound include a methyl etherified melamine resin and a water-soluble benzoguanamine resin. (5) Examples of the sulfonic acid group-containing compound include naphthalenedisulfonic acid. (6) As the hydroxyl group-containing compound, water-soluble hydroxyl group-containing compounds
Examples include a krill resin and a polyester resin.

The mixing ratio of the components (A) and (B) is determined by the molar ratio of the mutually reactive functional groups contained in each component. The ratio is such that the functional group in the component (B) is about 0.1 to less than the functional group in the component (A).
A range of 10 is appropriate.

Of course, if strict performance is not required, the range may be lower or higher. In order to accelerate the crosslinking reaction, a well-known and commonly used curing catalyst that catalyzes the above-described elementary reaction between the functional groups can be added.

The aqueous curable resin composition thus obtained includes titanium oxide, mica, talc, clay, precipitated barium sulfate, silica powder, calcium carbonate, iron oxide,
Inorganic pigments such as zinc oxide, aluminum powder, and carbon; organic pigments such as azo, phthalocyanine, and quinacridone; and plastic pigments; and further, these are dispersed in water with an emulsifier, a dispersant, or the like. Dispersed pigments can be used, and are selectively used according to their respective final purposes.

Further, various additives necessary for forming a coating material, for example, a dispersing agent, a wetting agent, a film-forming aid, a thickening agent, a thixotropic agent, an ultraviolet absorber, an antioxidant, a water repellent, an antifreeze. Agent,
The use of an antiseptic / deodorant or an antifoaming agent is selected and used in consideration of the performance of the obtained coating film.

Examples of the substrate coated with the aqueous curable resin composition of the present invention include metal, plastic, wood, glass, cement substrate, paper and fiber, and the like.

[0084] As a coating method, brush coating, spray coating, coating with a roll or a flow coater, and dip coating such as dipping are particularly typical.

After coating, if necessary, after a setting time, a cured film can be obtained by drying by heating at a low temperature or by drying at room temperature.
In the case of drying by heating, drying may be performed at an arbitrary temperature of about 120 ° C. or lower for an arbitrary time.

The water-based curable resin composition of the present invention has a high degree of weather resistance, chemical resistance, and stain resistance of the coating film, as well as long-term boiling water resistance and alkali resistance at high temperatures. From a place that has the characteristic of being excellent, as an exterior or interior water-based paint composition, or
It can be used as a coating or treating agent for metals, plastics, wood, inorganic substrates, paper or fibers.

[0087]

EXAMPLES Next, the present invention will be described more specifically with reference examples, examples and comparative examples. In the following, all parts and percentages are by weight unless otherwise specified. There is.

Reference Example 1 [Preparation Example of Fluororesin Aqueous Dispersion (A) Having Curable Site] A 2 liter stainless steel pressure-resistant reaction vessel (autoclave equipped with a stirrer, nitrogen introduction tube, thermometer and temperature controller) ) Was sufficiently replaced with nitrogen gas, 800 g of ion-exchanged water, 20 g of sodium dodecylbenzenesulfonate.
g, 20 of polyoxyethylene nonylphenyl ether
g, 10 g of Borax as a pH buffer is added and dissolved.

Next, 300 g of vinyl neodecanoate
100 g of vinyl acetate, 30 g of crotonic acid and 500 g of chlorinated trifluorotrifluoroethylene are charged. Further, ethylene gas is injected until the pressure becomes 15 kg / cm 2, and the internal temperature of the autoclave is raised to 80 ° C.

At this time, the pressure in the system during the reaction is approximately 30 k
The ethylene gas is adjusted to be g / cm2. Next, at the same temperature, an aqueous catalyst solution obtained by dissolving 5 g of potassium persulfate in 200 g of ion-exchanged water was placed in a reaction vessel at a temperature of 3 g.
Press in over time. After addition of the catalyst aqueous solution, the polymerization reaction is allowed to proceed at the same temperature for 10 hours.

The pH during the reaction proceeded at 3.5. During the reaction, the pressure in the system decreases as the monomer is consumed. In each case, the pressure in the reaction system is maintained at 30 kg / cm 2 by introducing ethylene.

After the completion of the reaction, the mixture is cooled to room temperature and
% Ammonia water until the pH becomes approximately 7.0, and 1 g of a 5% aqueous dispersion of "NOPCO 8034L" [a silicon-based defoaming agent manufactured by San Nopco] is added, followed by thorough stirring. .

Next, the unreacted gas is gradually taken out of the system, the pressure in the system is returned to normal pressure, and the unreacted gas dissolved in the dispersion is distilled off under reduced pressure. The obtained target dispersion has a carboxyl group as a curable site, a nonvolatile content of 48%, a pH of 7.0, a minimum film-forming temperature of 28 ° C., and a white particle having an average particle diameter of 80 nm. It was an aqueous dispersion. Hereinafter, this is referred to as (A-1).

Reference Example 2 [Preparation Example of Aqueous Fluororesin Dispersion Having Curable Site (A)] Same as Reference Example 1 except that the charged composition of the monomers was changed as shown in Table 1. By the above operation, the desired aqueous resin dispersion (A) was synthesized.

[0095] Also in these examples, the supply conditions of ethylene are the same as in Reference Example 1. The composition and the analysis value of the obtained dispersion are shown together in the same table. Reference Example 3 (Preparation Example of Fluororesin Aqueous Dispersion Having No Curable Site) A 2-liter stainless steel pressure-resistant reaction vessel (autoclave) equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a temperature controller was charged with nitrogen gas. Then, 800 g of ion-exchanged water, 20 g of sodium dodecylbenzenesulfonate, 20 g of polyoxyethylene nonylphenyl ether, and 10 g of borax as a pH buffer are added and dissolved.

Next, 300 g of vinyl neodecanoate was added.
130 g of vinyl acetate and 500 g of liquefied and collected chlorotrifluoroethylene are charged, and ethylene gas is further injected until the pressure becomes 15 kg / cm 2.

The internal temperature of the autoclave is raised to 80 ° C. At this time, the pressure in the system during the reaction was approximately 30 kg.
/ Cm 2 is adjusted to ethylene gas. Thereafter, at the same temperature, an aqueous catalyst solution obtained by dissolving 5 g of potassium persulfate in 200 g of ion-exchanged water was placed in a reaction vessel.
Press in for 3 hours.

After the addition of the catalyst aqueous solution, the polymerization reaction is allowed to proceed at the same temperature for 10 hours. The pH during the reaction proceeded at 3.5. During the reaction, with the consumption of the monomer,
As the pressure in the system decreases, the pressure of the reaction system is maintained at 30 kg / cm @ 2 by introducing ethylene each time.

After the completion of the reaction, the mixture is cooled to room temperature and
Aqueous ammonia is added until the pH is approximately 7.0,
Further, 1 g of a 5% aqueous dispersion of “Nopco 8034L”
And mix well.

Next, the unreacted gas is gradually removed from the system, the pressure in the system is returned to normal pressure, and the unreacted gas dissolved in the dispersion is distilled off under reduced pressure. Leave. The obtained dispersion was a white aqueous dispersion having a nonvolatile content of 48%, a pH of 7.0, a minimum film-forming temperature of 29 ° C, and an average particle size of 82 nm. Hereinafter, this is referred to as (R-1).

Reference Example 4 (same as above) A control aqueous solution having no curable site was prepared in the same manner as in Reference Example 3 except that the charged composition of the monomer was changed as shown in Table 1. A dispersion was synthesized. The composition and the analysis value of the obtained dispersion are shown together in the same table.

[0102]

[Table 1]

<< Footnotes to Table 1 >> CTFE: abbreviation for chlorotrifluoroethylene HFP: abbreviation for hexafluoropropylene VAc: abbreviation for vinyl acetate VV-10: abbreviation for vinyl ester of versatic acid having 10 carbon atoms BVE: Abbreviation of butyl vinyl ether CrA: Abbreviation of crotonic acid AGE: Abbreviation of allyl glycidyl ether DMAEMA: Abbreviation of dimethylaminoethyl methacrylate HBVE: Abbreviation of hydroxybutyl vinyl ether NV: Abbreviation of nonvolatile content (%) MFT: Minimum film formation temperature (° C.) Abbreviation Dia: Abbreviation of average particle diameter (nm)

[0104]

[Table 2]

Examples 1 to 4 (Blending of Aqueous Curable Resin Composition) Aqueous fluororesin dispersions (A-1 to A-) having carboxyl groups as curable parts obtained in Reference Examples 1 and 2
2) and a water-soluble curing agent as shown in Table 2 were each diluted so that the non-volatile content was 45%.
Various aqueous compositions were obtained by blending with the formulations shown in the same table.

Next, each of the obtained compositions was applied on a glass plate with a 3 mil applicator, and dried under the drying conditions described in the same table, and various performance evaluation tests were performed.
The results are summarized in the same table.

[0107]

[Table 3]

<< Footnotes in Table 2 >> * 1..., In the examples, there exists between the two components.
The compounds were blended such that the equivalent ratio of the mutually reactive functional groups became 1.

Reference Example 3 is obtained by removing the functional group from A-1 and is a comparative example of Reference Example 1. Reference example 4
Is a product obtained by removing a functional group from A-2.
Is a comparative example.

* 2 Each of the curing agents shown below was used by filtering an aqueous solution having a nonvolatile content of 4.5%.

Curing agent-1: a water-soluble epoxy resin,
Sorbitol polyglycidyl ether having a number average molecular weight of 406 and an average number of functional groups (epoxy group) in one molecule of 4 was used.

Curing agent-2: a water-soluble melamine resin,
Hexamethoxymethylolated melamine having a number average molecular weight of 390 and an average number of functional groups (methoxymethyl group) in one molecule of 6 was used.

Curing agent-3: A polymer having a number average molecular weight of 5,000 and consisting of n-butyl acrylate / acrylic acid / isocyanate ethyl methacrylate / methyl ethyl ketone adduct = 50/20/30 (weight ratio) was mixed with ammonia. The water-soluble curing agent obtained by summing was used.

[0114]

* 3... BcAc is an abbreviation for butyl carbitol acetate. 2% was added to the total amount of the used dispersion. * 4: A 70% paste of titanium oxide was blended so that the pigment volume concentration was 20%.

[0116] In the case of the pigment paste, "Boncoat 3750" (a polycarboxylic acid thickener manufactured by Dainippon Ink and Chemicals, Inc.) was used to adjust the stoma viscosity to 75 KU. And provided for the test.

* 5: Curing catalyst-1: Triethylamine was used, and 0.5% was added to the total amount of the dispersion. Curing catalyst-2: Naphthalenedisulfonic acid was used, and 2% was added to the total amount of the dispersion.

* 6: A (dry for one week at room temperature), B
(After drying at 60 ° C. for 20 minutes, drying at room temperature for 1 week), C
(After drying at 100 ° C. for 20 minutes, then drying at room temperature for 1 week) * 7 This gel fraction is obtained by peeling the dried film obtained on a glass plate and immersing it in acetone for 24 hours. The gel portion of the film remaining undissolved in acetone was weighed and expressed as a percentage of the initial dry film weight.

* 8: Stain resistance: A carbon paper of 1 cm × 1 cm is placed on the dried film obtained on the glass plate, and the glass plate is placed on the carbon paper, and a 2 kg weight is placed thereon. Then, the film is put in a dryer at 80 ° C., left for 20 minutes, taken out, and the state of adhesion of carbon paper stain on the dried film is observed.

A sample without any stain was marked with “◎”, and a sample with slight stain was marked with “○”, and the sample was completely stained or carbon paper was removed from the dry film. Those that were not peeled were evaluated as "x".

* 9: Accelerated weather resistance: The appearance of each coating film after a 3,000-hour exposure test was visually determined using a Du Panel light control weather meter.

When the dried film was free from any abnormalities such as discoloration or peeling, it was marked with “◎”. When the blister or peeling was slightly observed, it was marked with “○”. Those that were markedly deteriorated were evaluated as “x”.

[0123]

[Table 4]

Comparative Examples 1-2 Each of the aqueous dispersions (R-1 to R-2) obtained in Reference Examples 3 and 4 was diluted to a nonvolatile content of 45% in the same manner as in Examples 1 to 4. After that, an aqueous composition for a subject was obtained with the composition shown in Table 2.

Each of the obtained compositions was applied on a glass plate with a 3 mil applicator, dried under the drying conditions described in the same table, and subjected to various performance evaluation tests. The results are summarized in the same table.

[0126]

[Table 5] Comparative Example 2 is a combination of A-1 of Example 1 from which the functional groups were removed and a crosslinking agent.
Is a comparative example.

A coating film obtained by using the aqueous curable resin composition of the present invention containing a fluororesin aqueous dispersion and its curing agent as main components has excellent performance in any of the tests. It will be known that it is.

[0128]

The fluororesin aqueous dispersion obtained as described above enables the curability of a fluoroolefin emulsion copolymer at a relatively low temperature, which has been difficult so far,
The purpose of the present invention is to provide a coating film having long-term weather resistance without impairing stain resistance.

The fact that the aqueous curable resin composition of the present invention comprises such a highly practical aqueous fluororesin dispersion as a base resin component is not corrected. It can be said that it guarantees outstanding utility.

Continuation of the front page (56) References JP-A-3-88882 (JP, A) JP-A-61-261367 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 27 / 12-27/20 C09D 5/00-5/46 C09D 127/12-127/20

Claims (2)

(57) [Claims] An aqueous dispersion (A) of a fluororesin having a curable site (a) and a functional group capable of mutually reacting with the curable site (a) of the aqueous dispersion (A) of the fluororesin. An aqueous curable resin composition comprising, as an essential component, a water-soluble curing agent (B) having b), wherein the curable site (a) is a carboxyl group, and the fluororesin is croton. An acid and / or itaconic acid as an essential acid group-containing monomer component, and wherein the aqueous dispersion (A) of the fluororesin is one or two selected from the group consisting of alkylbenzenesulfonates and vinylsulfonates An aqueous dispersion obtained by polymerizing a monomer having the curable site (a) in an aqueous medium in the presence of an emulsifier comprising a polyoxyethylene alkyl ether as described above and / or Resin composition. 2. The aqueous curing method according to claim 1, wherein the functional group (b) capable of reacting with the curable site (a) in the water-soluble curing agent (B) is an epoxy group or a blocked isocyanate group. Resin composition.