JP3013952B2 - Aqueous resin composition for coating - 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 resin composition for covering, for example, mastic paints, sound-proof paints, vibration-proof paints, caulking materials, etc. A water-based resin composition for coating used as a coating material for protecting metal working members from scratches or so-called "chipping" of outdoor metal working members such as chassis, suspensions, etc.

[0002] Even when a thick coating film of, for example, 600 µ or more is formed, the drying process does not cause blisters or cracks in the film, and the formed film has a thickness of, for example, about 300 µ. The coating has excellent chipping resistance even when it is relatively thin, that is, chipping resistance at normal temperature (hereinafter, sometimes referred to as normal chipping resistance) and chipping resistance when the coating film is wet (hereinafter, referred to as “chipping resistance”). Impact resistance at ordinary temperature and at extremely low temperatures such as -30 ° C (hereinafter sometimes referred to as low-temperature impact resistance); excellent adhesion to metal-worked members; A good balance of properties as a chipping-resistant coating agent, such as uniformity and smoothness; water resistance; gasoline resistance;
The present invention relates to a coating aqueous resin composition having excellent properties.

[0004] More specifically, the (co)
The present invention relates to an aqueous resin composition for coating, comprising a polymer, a deformable inorganic filler, and thermally expandable polymer beads and / or hollow polymer beads.

[0004]

2. Description of the Related Art Conventionally, a rubber-based latex or an acrylic emulsion has been used as a vehicle as an aqueous chipping-resistant coating material used for outdoor metal working members of vehicles such as automobiles, and powdered inorganic materials such as calcium carbonate and talc have been used. What mix | blends the agent is known. Since these coating agents need to maintain the elasticity of the coating from the viewpoint of chipping resistance, the amount of the powder filler is naturally limited,
Further, the coating is required to have a much thicker film thickness than a general coating agent, and is applied by, for example, airless spray coating or the like so that the dry coating has a thickness of about 200 to 800 μm.

In general, in the case of an aqueous coating agent, if an attempt is made to form a thick film having a small content of an inorganic filler, water is evaporated at the time of heating and drying, so that blisters are easily generated in the film. In coatings for chipping resistance, the balance between chipping resistance and anti-swelling properties of the film has been studied as a serious problem to be solved. For example, JP-A-59-75954, JP-A-62 230868
Some proposals described in Japanese Patent Application Laid-Open No. 63-10678 and Japanese Patent Application Laid-Open No. 63-172777 are known.

[0006] However, these proposals do not always sufficiently overcome the above-mentioned problems of the balance between the chipping resistance and the swelling prevention of the coating film.
In addition, problems have been found such that the adhesion of the coating immediately after being wet with water to a metal processing member (hereinafter, sometimes referred to as water resistance adhesion) may be reduced.

[0007] The present inventors, as described above, for example, 600
Even when a thick film such as μ or more is formed, blisters do not occur in the drying process, and the formed film is, for example, about 300μ, and is excellent in chipping resistance even when this kind of film is relatively thin. Properties, in particular, it can exhibit excellent chipping resistance even at an extremely low temperature such as -30 ° C, and further, the adhesion of the base material to the metal processing member,
Rust prevention, flat and uniform film formation, water adhesion,
As a result of research on obtaining a coating for water-based chipping resistance having excellent properties such as gasoline resistance, cold bending resistance, impact resistance, and soundproofing properties, as a vehicle, for example, -30
It has been found that these problems can be solved by using a (co) polymer having a glass transition point of about ° C and using an irregularly shaped inorganic filler such as "gold rice sugar" as the filler. A patent application was filed as "aqueous coating composition for chipping" (Japanese Patent Application No. 2-325544).

[0008]

However, after that, the above-mentioned aqueous coating composition for chipping resistance has a problem that, depending on the amount of the irregularly shaped inorganic filler, cracks may occur in the coating due to rapid drying shrinkage during heating and drying. It turned out that there was a point, and as a result of further research, the aqueous coating composition further contained, for example, heat-expandable polymer beads or hollow polymer beads that expand when heated at about 110 ° C., The present inventors have found that it is possible to obtain an excellent coating aqueous resin composition capable of preventing the occurrence of cracks in a coating film while maintaining the excellent properties of the aqueous coating composition, and to complete the present invention. Reached.

[0009]

Means for Solving the Problems The present invention provides the following (A) to
(C), (A) a (co) polymer having a glass transition point of 0 ° C. or less, (B) a deformed inorganic filler having a spheroid coefficient of 5 or more and an average particle size of about 1 to 5 μm, and (C) heat It is an object of the present invention to provide an aqueous resin composition for coating, comprising an expandable polymer bead and / or a hollow polymer bead.

Hereinafter, the present invention will be described in detail. The (co) polymer of (A) used in the present invention is not particularly limited, and is a water-dispersible (co) polymer obtained by aqueous emulsion polymerization of various vinyl monomers. Therefore, those having a glass transition point of 0 ° C. or lower can be suitably used.

Such water-dispersible (co) polymers include:
For example, an acrylic (co) polymer emulsion, a synthetic rubber-based copolymer latex and the like can be exemplified. These water-dispersible (co) polymers can be used alone or in combination of two or more.

Examples of the acrylic (co) polymer emulsion include the following monomers (a) to (d), (a)
(1)

[0013]

Embedded image

(However, R ¹ represents H or a methyl group, and R ² represents a linear or branched alkyl group having 1 to 20 carbon atoms.)

30 to 100% by weight of at least one (meth) acrylate monomer selected from the group consisting of: (b) 0 to 5% by weight of an ethylene monomer containing a carboxyl group in the molecule; and (c) a monomer having at least one functional group in addition to one radically polymerizable unsaturated group in the molecule, wherein the monomer other than the monomer (b) is 0 to 15% by weight. , (D) copolymerizable with the monomers (a) to (c) and the monomers (a) to (c)
Monomer other than 0 to 50% by weight (however, monomers (a) to (d)
To 100% by weight)) by aqueous emulsion polymerization
A (co) polymer emulsion can be exemplified.

In the monomer (a) represented by the general formula (1), R ¹ is H or a methyl group, and R ² has 1 carbon atom.
And an alkyl ester-based monomer of acrylic acid or methacrylic acid represented by up to 20 linear or branched alkyl groups.

In these monomers, when R ¹ is H, that is, in the case of an acrylate monomer, R ² has a carbon number from the viewpoint of easy availability and easy polymerization reaction. 1-1
It is preferably 0 straight-chain or branched alkyl group.
Examples of such an alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-
Butyl group, t-butyl group, n-pentyl group, n-hexyl group,
n-heptyl group, n-octyl group, i-octyl group, 2-ethylhexyl group, n-nonyl group, i-nonyl group, n-decyl group, and the like,

Specifically, for example, methyl acrylate, ethyl acrylate, n-butyl acrylate, i-butyl acrylate, n-octyl acrylate, i-octyl acrylate, 2-ethylhexyl acrylate, i-nonyl acrylate and the like are preferably used. it can.

When R ¹ is a methyl group, that is, in the case of a methacrylate ester monomer, R ² has 1 to 1 carbon atoms for the same reason as in the case of the acrylate ester monomer. Preferred are 15 straight-chain or branched alkyl groups, such alkyl groups include, for example, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl , N-pentyl group, n-hexyl group, n-
Heptyl group, n-octyl group, i-octyl group, 2-ethylhexyl group, n-nonyl group, i-nonyl group, n-decyl group, n-dodecyl group, t-dodecyl group, etc.

Of these, the use of a methacrylic acid ester monomer having a linear or branched alkyl group having 1 to 4 carbon atoms is particularly preferred. Specific examples thereof include methyl methacrylate, ethyl methacrylate, and n-butyl. Methacrylate, i-butyl methacrylate and the like can be suitably used.

The amount of the above-mentioned monomer (a) used for the alkyl ester monomer of acrylic acid or methacrylic acid is as follows.
In general, 30 to 100% by weight, preferably 42 to 99.5% by weight, particularly preferably 52 to 9% by weight, based on the total 100% by weight of (a) to (d).
It should be 9.5% by weight. If the amount of the monomer (a) used is not less than the lower limit, during aqueous emulsion polymerization, inconveniences such as generation of aggregates and destruction of the emulsified state do not occur. If it is the following, it does not cause a decrease in mechanical stability or storage stability of the obtained copolymer emulsion, and also has an adhesion to a base material such as a metal processing member of the obtained coating aqueous resin composition. It is preferable because it is excellent.

The ethylene monomer having a carboxyl group in the molecule (hereinafter sometimes referred to as a carboxyl group-containing monomer) (b) includes, for example, acrylic acid,
Α, β-unsaturated mono- or di-carboxylic acids having 3 to 5 carbon atoms, such as methacrylic acid, crotonic acid, citraconic acid, itaconic acid, maleic acid, and fumaric acid (hereinafter may be abbreviated as ethylene carboxylic acid) For example); anhydrides of α, β-unsaturated dicarboxylic acids having 4 to 5 carbon atoms such as maleic anhydride;

For example, mono-n-butylmalate, mono-n-
C1-C12 monoalkyl ester monomers of α, β-unsaturated dicarboxylic acids having 4 to 5 carbon atoms such as butyl fumarate and monoethyl itaconate; for example, ethylene-based monomers such as sodium acrylate and ammonium methacrylate Examples thereof include ammonium salts or alkali metal salts of carboxylic acids or α, β-unsaturated dicarboxylic acid monoalkyl ester monomers having 4 to 5 carbon atoms. Of these, the use of ethylene-based carboxylic acids is preferred from the viewpoints of ease of emulsion polymerization and low generation of aggregates, and the use of acrylic acid, methacrylic acid and / or itaconic acid is particularly preferred.

The amount of the monomer (b) used is from the monomers (a) to
It is generally 0 to 5% by weight, preferably 0.5 to 3% by weight, based on the total 100% by weight of (d). If the amount of the monomer (b) is less than or equal to the above upper limit, the occurrence of aggregates or destruction of the emulsified state during aqueous emulsion polymerization, or a decrease in the storage stability of the obtained emulsion may be caused. Not preferred. On the other hand, when the amount is 0.5% by weight or more, the formation of aggregates during aqueous emulsion polymerization is suppressed, the mechanical stability of the obtained copolymer emulsion is improved, and the obtained aqueous resin composition for coating is obtained. This is preferable because the adhesion of the object to a substrate such as a metal processing member is also excellent.

The monomer (c) is a monomer having at least one functional group in addition to one radically polymerizable unsaturated group in the molecule, and is a monomer other than the monomer b. Monomer, such as acrylamide, methacrylamide, diacetone acrylamide, N-
Amides of ethylene-based carboxylic acids such as methylol acrylamide and N-methylol methacrylamide or derivatives thereof; for example, esters of ethylene-based carboxylic acids such as glycidyl acrylate and glycidyl methacrylate with saturated alcohols having an epoxy group;

Esters of ethylene-based carboxylic acids such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate with polyhydric saturated alcohols; for example, dimethylaminoethyl methacrylate Esters of an ethylenic carboxylic acid such as diethylaminoethyl methacrylate and a saturated alcohol having an amino group;

For example, two or more of divinylbenzene, diallyl phthalate, triallyl cyanurate, ethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol dimethacrylate, allyl methacrylate, etc. A monomer having a radical polymerizable unsaturated group;
And the like.

The amount of the monomer (c) used is from monomer (a) to monomer (a).
The amount is preferably 0 to 15% by weight based on the total 100% by weight of (d). The use amount of 15% by weight or less is preferable because problems such as generation of aggregates and destruction of the emulsified state during aqueous emulsion polymerization, or reduction in storage stability of the obtained aqueous dispersion are not caused. .

Further, the monomer (d) is a monomer which is copolymerizable with the monomers (a) to (c) and is other than the monomers (a) to (c). Examples of such a monomer include aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, and ethylvinylbenzene; vinyl cyanide-based monomers such as acrylonitrile and methacrylonitrile; A saturated fatty acid vinyl monomer having 1 to 12 carbon atoms such as vinyl formate, vinyl acetate, vinyl propionate and vinyl versatate; for example, dibutyl malate;
Dioctyl fumarate, dibutyl fumarate, dioctyl fumarate, dibutyl itaconate, dioctyl itaconate and the like; unsaturated C4 to C5 unsaturated α, β-dicarboxylic acid C1 to C12 dialkyl ester monomers; A group of monomers may be mentioned.

The amount of the comonomer (d) used is generally from 0 to 5 based on 100% by weight of the total of the monomers (a) to (d).
0% by weight, preferably 0-40% by weight, particularly preferably 0%
About 30% by weight.

As the “(co) polymer emulsion formed by aqueous emulsion polymerization” which can be used in the present invention, the above-mentioned monomer groups (a) to (d) can be used in the presence of a surfactant and / or a protective colloid. A (co) polymer emulsion obtained by emulsion polymerization in an aqueous medium below can be exemplified.

As the above-mentioned surfactants, nonionic surfactants include, for example, polyoxyalkylene alkyl (or alkenyl) ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; for example, polyoxyethylene octyl phenol Ethers, polyoxyalkylene alkylphenol ethers such as polyoxyethylene nonylphenol ether;

For example, sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate; polyoxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate; Polyoxyalkylene fatty acid esters such as laurate and polyoxyethylene monostearate;
For example, glycerin fatty acid esters such as oleic acid monoglyceride and stearic acid monoglyceride; polyoxyethylene polypropylene block copolymer;
And the like.

Examples of the anionic surfactants include, for example,
Fatty acid salts such as sodium stearate, sodium oleate and sodium laurate; alkylaryl sulfonates such as sodium dodecylbenzenesulfonate; alkyl sulfate salts such as sodium lauryl sulfate; for example, sodium monooctyl sulfosuccinate Alkylsulfosuccinates and their derivatives, such as sodium, dioctylsulfosuccinate and polyoxyethylene laurylsulfosuccinate;

For example, polyoxyalkylene alkyl ether sulfates such as polyoxyethylene lauryl ether sodium sulfate; polyoxyalkylene alkyl aryl ether sulfates such as polyoxyethylene nonylphenol ether sodium sulfate; and the like. .

The cationic surfactants include, for example, alkylamine salts such as laurylamine acetate;
For example, lauryl trimethyl ammonium chloride,
Examples of the amphoteric surfactants include quaternary ammonium salts such as alkylbenzyldimethylammonium chloride and the like; and alkyl betaines such as lauryl betaine.

Further, those in which a part of hydrogen of the alkyl group of these surfactants is substituted with fluorine can also be used. Further, so-called reactive surfactants having a radical copolymerizable unsaturated bond in the molecular structure of these surfactants can also be used.

Among these surfactants, non-ionic surfactants include polyoxyalkylene alkyl ethers, polyoxyalkylene alkyl phenol ethers, and polyoxyalkylene alkyl phenol ethers, from the viewpoint of low generation of aggregates during emulsion polymerization. Examples of the ionic surfactants include alkyl aryl sulfonates; alkyl sulfates; alkyl sulfosuccinates and derivatives thereof; polyoxyalkylene alkyl ether sulfates; polyoxyalkylene alkyl phenol ether sulfates; preferable. These surfactants can be used alone or in an appropriate combination.

The amount of these surfactants to be used is generally about 100% by weight of the total of the monomers (a) to (d).
0.5 to 10 parts by weight used, polymerization stability of aqueous emulsion polymerization,
From the viewpoint of storage stability of the (co) polymer emulsion and excellent adhesion to a substrate such as a metal processing member when used as the coating aqueous resin composition of the present invention, about 1 to 6 parts by weight It is particularly preferable to use about 1 to 4 parts by weight.

Examples of protective colloids usable in the acrylic (co) polymer emulsion used in the present invention include, for example, polyvinyl alcohols such as partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, and modified polyvinyl alcohol; Cellulose derivatives such as hydroxyethylcellulose, hydroxypropylcellulose and carboxymethylcellulose; and natural polysaccharides such as guar gum. The amount of these protective colloids used is, for example, a total of the monomers (a) to (d) of 10
The amount is preferably about 0 to 3 parts by weight with respect to 0 parts by weight.

In the emulsion polymerization, as a polymerization initiator,
For example, ammonium persulfate, potassium persulfate, persulfates such as ammonium persulfate; t-butyl hydroperoxide, cumene hydroperoxide, organic peroxides such as p-menthane hydroperoxide; hydrogen peroxide; One or more of them can be used in combination. The amount can be appropriately selected, but for example, about 0.05 to 1 part by weight, more preferably about 0.1 to 0.7 part by weight, based on 100 parts by weight of the total of the monomers (a) to (d) used. Particularly preferably, the amount is about 0.1 to 0.5 part by weight.

In the emulsion polymerization, a reducing agent can be used together if desired. Examples of the reducing agent include reducing organic compounds such as ascorbic acid, tartaric acid, citric acid, and glucose; and reducing inorganic compounds such as sodium thiosulfate, sodium sulfite, sodium bisulfite, and sodium metabisulfite. Can be. The amount of the reducing agent can be appropriately selected, for example, the monomers used (a) to (d)
Is preferably about 0.05 to 1 part by weight with respect to 100 parts by weight in total.

In the emulsion (co) polymerization, a chain transfer agent may be used if desired. Such chain transfer agents include, for example, cyanoacetic acid; C1-8 alkyl esters of cyanoacetic acid; bromoacetic acid; C1-8 alkyl esters of bromoacetic acid; anthracene, phenanthrene, fluorene, 9-phenyl Aromatic compounds such as fluorene; aromatic nitro compounds such as p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol, p-nitrotoluene; benzoquinone, 2,3,5,6- Benzoquinone derivatives such as tetramethyl-p-benzoquinone;

Borane derivatives such as tributylborane; carbon tetrabromide, carbon tetrachloride, 1,1,2,2-tetrabromoethane, tribromoethylene, trichloroethylene, bromotrichloromethane, tribromomethane, 3-chloro-1 -Halogenated hydrocarbons such as propene; aldehydes such as chloral and furaldehyde; alkyl mercaptans having 1 to 18 carbon atoms; aromatic mercaptans such as thiophenol and toluene mercaptan; mercaptoacetic acid; 10 alkyl esters; C1-C12 hydroxyalkyl mercaptans; terpenes such as binene and terpinolene;

When the above chain transfer agent is used, the amount of the chain transfer agent used is about 100 parts by weight of the total of the monomers (a) to (d).
It is preferably 0.005 to 3.0 parts by weight.

The polymerization temperature is generally about 30 to 100 ° C.,
Preferably, the range is about 40 to 90 ° C.

The acrylic (co) polymer emulsion used in the present invention is not particularly limited.
Solid content is about 10-70% by weight, pH 2-10, viscosity is 10,000cps or less (B-type rotational viscometer, 25 ° C, 20RPM). About 30-65% by weight of solid content due to ease of production and good productivity. (Particularly about 40 to 60% by weight), pH 2 to 8, and viscosity about 50 to 5000 cps.

As the pH adjuster, aqueous ammonia, an aqueous solution of water-soluble amines or alkali hydroxide or the like can be used.

The acrylic (co) used in the present invention
The Tg of the polymer is 0 ° C. or lower, preferably −10 to −50.
° C, particularly preferably -20 to -40 ° C. If the Tg of the (co) polymer exceeds the upper limit and is too high, the low-temperature impact resistance of the resulting aqueous resin composition for coating may be undesirably reduced. On the other hand, if the lower limit is not less than the lower limit, it is preferable because the film strength of the coating composition is not reduced and the normal and wet chipping resistance is excellent.

In the present invention, the Tg of the acrylic (co) polymer is a value measured and determined as follows.

Glass transition point: In a cylindrical cell made of aluminum foil having a thickness of about 0.05 mm and having an inner diameter of about 5 mm and a depth of about 5 mm,
(Co) Weigh out about 10 mg sample of polymer emulsion, 100 ℃
The sample dried for 2 hours is used as a measurement sample. Using a differential scanning calorimeter (Differential Scanning Calorimeter: SSC-5000 type manufactured by Seiko Instruments Inc.), the measurement is determined at a heating rate of 10 ° C./min from −150 ° C.

Further, the acrylic (co) polymer (A) of the present invention
Generally has a weight average molecular weight of 500,000 or more, especially 800,000 or more. In addition, the average particle size of the acrylic (co) polymer emulsion-dispersed particles (hereinafter, may be simply referred to as the particle size) is generally 0.05 to 0.5 µ, particularly preferably 0.1 to 0.3 µ. When the particle diameter is equal to or less than the upper limit, sedimentation, separation, and the like are less likely to occur even when the obtained aqueous resin composition for coating is stored for a long period of time. On the other hand, when the value is equal to or more than the lower limit, generation of aggregates and emulsion destruction do not occur during emulsion polymerization of the emulsion.

The particle size of the acrylic (co) polymer (A) is as follows: “New Experimental Chemistry Course 4 Basic Technology 3
(II), pp. 725-741 (issued by Maruzen Co., Ltd. on July 20, 1976)
And specifically measured by the method described below. Average particle size: Dilute an aqueous dispersion such as a (co) polymer emulsion with 50,000 to 150,000 times with distilled water, mix well with stirring, and collect about 10 ml using a Pasteur pipette in a 21 mmφ glass cell And the dynamic light scattering photometer DLS-700
It is set at a predetermined position (manufactured by Otsuka Electronics Co., Ltd.) and measured under the following measurement conditions.

Measurement conditions Measurement temperature 25 ± 1 ° C. Clock rate 10 μsec Correlation channel (Corel. Channel) 512 Total number of measurements 200 times Light scattering angle 90 ° Computer processing of the above measurement results and average particle size Find the diameter.

The synthetic rubber-based copolymer latex that can be used in the present invention contains a conjugated diolefin-based monomer and an aromatic vinyl monomer and / or a vinyl cyanide monomer as main components. For example, a monomer obtained by aqueous emulsion copolymerization under elevated pressure can be exemplified.

Examples of the conjugated diolefin-based monomer include butadiene, isoprene, chloroprene and the like. The amount of these conjugated diolefin monomers used is 100% by weight of the total of the monomer components constituting the synthetic rubber.
In general, it is good to be 20 to 75% by weight, preferably 30 to 50% by weight. If the amount is less than the upper limit,
It is preferable because the film strength of the aqueous resin composition for coating using the obtained synthetic rubber-based copolymer latex does not decrease, and on the other hand, if it is equal to or more than the lower limit, a substrate such as a metal working member of the composition is used. This is preferable because the adhesion to the toner does not decrease.

As the aromatic vinyl monomer and vinyl cyanide monomer, the aromatic vinyl monomer and vinyl cyanide monomer exemplified as the monomer (c) in the acrylic (co) polymer emulsion are used. Bodies, ie, for example, styrene, α-methylstyrene, vinyltoluene, ethylvinylbenzene, and the like; and, for example, acrylonitrile,
Methacrylonitrile and the like;

The amount of the aromatic vinyl monomer and / or vinyl cyanide monomer used is generally 20 to 75% by weight based on 100% by weight of the total of the monomer components constituting the synthetic rubber. Preferably, it is 40 to 70% by weight. When the amount is not less than the lower limit, the coating strength of the aqueous resin composition for coating using the obtained synthetic rubber-based latex is preferably not reduced. This is preferable because the film formability of the product is excellent and the adhesion to a substrate such as a metal processing member does not decrease.

The synthetic rubber-based copolymer latex which can be used in the present invention includes, in addition to these conjugated diolefin-based monomers, aromatic vinyl monomers and vinyl cyanide monomers, if necessary, Other comonomers copolymerizable with the monomer can be used.

As these comonomers, acrylic or methacrylic acid ester monomers of the general formula (1) exemplified as the monomer (a) in the acrylic (co) polymer emulsion; Monomers in emulsions
a carboxyl group-containing monomer exemplified as (b); an amide of an ethylene-based carboxylic acid or a derivative thereof exemplified as the monomer (c) in the emulsion, a mixture of an ethylene-based carboxylic acid and a saturated alcohol having an epoxy group. Esters, esters of an ethylene-based carboxylic acid and a polyhydric saturated alcohol;

The amount of these monomers used is generally from 0 to 20% by weight of a (meth) acrylate monomer based on 100% by weight of the total of the monomer components constituting the synthetic rubber; 0 to 5% by weight of contained monomers; amides of ethylene-based carboxylic acid or derivatives thereof, esters of ethylene-based carboxylic acid and saturated alcohol having an epoxy group, and / or ethylene-based carboxylic acid and polyvalent saturated alcohol 0 to 5% by weight of an ester;

The above synthetic rubber-based copolymer latex is
As in the case of the acrylic (co) polymer emulsion, these monomers can be obtained by emulsion copolymerization in an aqueous medium in the presence of a surfactant and / or a protective colloid.

Examples of usable surfactants and protective colloids include nonionic surfactants, anionic surfactants, and cationic surfactants which can be used in the case of aqueous emulsion polymerization of the acrylic (co) polymer emulsion. Examples thereof include ionic surfactants and amphoteric surfactants; polyvinyl alcohols, cellulose derivatives, and natural polysaccharides; the amounts used are almost the same as those used in the production of the emulsion.

Further, a polymerization initiator, a reducing agent, a chain transfer agent,
As the pH adjuster and the like, those which can be used in the acrylic (co) polymer emulsion can be used in substantially the same amount.

The glass transition point of the synthetic rubber copolymer used in the present invention is 0 ° C. or lower, preferably -10 to -80.
° C, particularly preferably -20 to -60 ° C. If the glass transition point of the (co) polymer is too high exceeding the upper limit, the chipping resistance at extremely low temperatures of the obtained aqueous resin composition for coating may decrease, which is not preferable. The lower limit value or more is preferable because the film strength of the coating composition does not decrease and the normal and wet chipping resistance are excellent.

The above synthetic rubber copolymer preferably has a gel fraction in the range of generally 60 to 98% by weight, particularly 70 to 95% by weight.

The gel fraction of the synthetic rubber-based copolymer is as follows:
It is a value obtained by measuring by the following method.

Gel fraction: A film was prepared from a synthetic rubber-based copolymer latex by drying at room temperature, and this film was
After throwing in 0-800 times toluene and leaving to stand for 48 hours
Filter using No. 2 filter paper. The filtrate was dried under reduced pressure at 70 ° C. and weighed to determine the toluene-soluble matter (% by weight) of the rubber-based copolymer film, and the value obtained by subtracting the toluene-soluble matter from 100% by weight, ie, the toluene-insoluble matter ( % By weight) is defined as the gel fraction.

Further, the particle diameter of the synthetic rubber-based copolymer latex dispersed particles is generally 0.05 to 0.5 μm, especially 0.1 to 0.5 μm.
It is desirably within the range of 0.3 μm.

The particle diameter of the synthetic rubber-based copolymer latex dispersed particles is a value measured in the same manner as in the case of the acrylic (co) polymer emulsion-dispersed particles.

Examples of the synthetic rubber latex that can be used in the present invention include LX-407C [Nippon Zeon Co., Ltd.
Co., Ltd.), SN-318, SN-534, SN-562, J-1666 (or more, manufactured by Sumitomo Dow), SK-80 (manufactured by Takeda Pharmaceutical Co., Ltd.), L-200
1, L2337 (above, manufactured by Asahi Kasei Corporation), Polyrac 707
Styrene-butadiene-based synthetic rubber latex (hereinafter sometimes abbreviated as SBR) sold under trade names such as [Mitsui Toatsu Chemical Co., Ltd.]; Nipol 1571, Nipol 1551,
Examples include acrylonitrile-butadiene-based synthetic rubber latex (hereinafter sometimes abbreviated as NBR), which is commercially available under a trade name such as Nipol 1562 (both manufactured by Nippon Zeon Co., Ltd.).

The aqueous resin composition for coating of the present invention comprises the (co) polymer (A) having a glass transition point of 0 ° C. or lower as described above, and a modified inorganic filler (B). . The “irregular shape” in the irregular inorganic filler refers to a shape having a spherical surface coefficient of 5 or more, for example, an extremely large specific surface area having a convex surface such as “confetti”, and the following formula (2):

[0073]

S 1 spherical coefficient = − = − dρS (2) S′6 where S: specific surface area of inorganic filler d: average particle diameter of inorganic filler ρ: Density of inorganic filler S ': specific surface area of sphere with diameter d and density ρ

It is preferable that the spherical coefficient defined by the above is 5 or more. When the spherical coefficient is 5 or more, it is possible to prevent the occurrence of blisters when forming a relatively thick coating film of the coating aqueous resin composition, and the obtained coating film has excellent chipping resistance.

The average particle size of the irregular inorganic filler is preferably about 1 to 5 μm. When the average particle size is 1 μ or more, the workability during coating is excellent, and when the average particle size is 5 μ or less, the chipping resistance and the water resistance of the coating film of the obtained aqueous resin composition are remarkably improved. Is preferred.

Examples of such deformable inorganic fillers include deformable precipitated calcium carbonate sold under the trade names such as Fikerbo H and Ficarbo S (all manufactured by Pfizer).

The amount of the modified inorganic filler used is
(Co) 100 parts by weight of the polymer, for example, 10 to 400 parts by weight,
The amount is preferably about 20 to 300 parts by weight, particularly preferably about 30 to 200 parts by weight. When the amount used is equal to or less than the upper limit, the finished appearance of the coating film using the obtained composition is excellent, and the adhesiveness to a substrate such as a metal processing member is preferably excellent. If the lower limit value or more, the chipping resistance of the obtained film is excellent, which is preferable.

The aqueous resin composition for coating according to the present invention comprises, together with the (co) polymer (A) having a glass transition point of 0 ° C. or lower and the modified inorganic filler (B), thermally expandable polymer beads and / or
Alternatively, it comprises a hollow polymer bead (C).

The above-mentioned heat-expandable polymer beads are obtained by encapsulating a heated vaporized foaming agent or a thermally decomposable foaming agent in polymer beads having a thermoplastic resin as a shell wall.

The above-mentioned thermoplastic resin is not particularly limited as long as it is softened at the heating temperature at the time of forming a film using the obtained aqueous resin composition for coating. C., in particular, a resin that softens at about 70 to 120.degree. C. is preferable. For example, vinyl resins such as polyolefin, polyacrylonitrile, polyacrylate, polystyrene, polyvinyl chloride, polyvinylidene chloride and copolymers thereof; polyesters resin;
Thermoplastic resins such as silicone resin; thermoplastic urethane resin;

Examples of the heat-evaporating foaming agent include, for example,
Organic solvents such as hydrocarbon-based, halogenated hydrocarbon-based, ester-based, ether-based and ketone-based organic solvents having a low boiling point such as about 50 to + 50 ° C can be used.

Examples of the thermal decomposition type foaming agent include, for example,
Nitroso compounds such as N, N'-dinitrosopentamethylenetetramine and N, N'-dimethyl-N, N'-dinitrosoterephthalamide; azo compounds such as azodicarbonamide;
For example, sulfonylhydrazide compounds such as benzenesulfonylhydrazide, p, p'-oxybis (benzenesulfonylamide), benzene-1,3-disulfonylhydrazide, toluenesulfonylhydrazide and derivatives thereof; p-toluenesulfonyl semicarbazide; trihydrazinotriazine And the like.

The thermal expansion polymer beads have a thermal expansion temperature of, for example, 60 to 180 ° C.
It is about 0 to 160 ° C., and various kinds of stability before and after thermal expansion, excellent in safety, and easily available are preferable.Acrylonitrile-vinylidene chloride copolymer and other vinyl resins are used as shell walls. It is particularly preferable that a hydrocarbon-based organic solvent such as isobutane is included as a heat-evaporating foaming agent.

The thermally expandable polymer beads have an average particle diameter before thermal expansion of 1 to 50 μm, particularly about 3 to 40 μm, and an average particle diameter after thermal expansion of 5 to 300 μm.
μ, particularly preferably about 20 to 200 μ.

Examples of such thermally expandable polymer beads that can be suitably used in the present invention include Matsumoto Microspheres F-30 and F-50 (all manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.), Exppan Cell WU ^# 642, WU ^# 551, WU ^# 46
1, DU ^# 551, DU ^# 461, DU ^# 051
And the like.

Some of these heat-expandable polymer beads are commercially available as a so-called “wet cake” containing water for reasons such as easy handling, and the above “Matsumoto Microsphere F” is used. -30, F-50 "and" Expancel WU # 642, WU ^# 551, WU ^# 461 "are of this type.

The hollow polymer beads usable in the present invention include, for example, polyolefins, polyacrylonitriles, polyacrylates, polystyrenes, polyvinyl chlorides, polyvinylidene chlorides and the like as in the above-mentioned heat-expandable polymer beads. Copolymer; polyester resin; silicone resin; thermoplastic urethane resin; and the like having a shell wall made of a thermoplastic resin. For example, the thermally expandable polymer beads are thermally expanded in advance under appropriate heating conditions. Can be suitably used. In addition, those using a thermosetting resin such as an amino resin, a phenol resin, or an unsaturated polyester resin as the shell wall can also be used.

The average particle size of such hollow polymer beads is generally about 1 to 500 μm, preferably about 5 to 300 μm.

The hollow polymer beads that can be suitably used in the present invention include, for example, Expancel DE ^#
551 and WE ^# 551 (both manufactured by Nippon Philite Co., Ltd.). As in the case of the above-mentioned heat-expandable polymer beads, these hollow polymer beads may be commercially available as a so-called "wet cake" containing water for reasons such as easy handling. "Expancel WE ^# 551" is this type.

The amount of the heat-expandable polymer beads and / or hollow polymer beads (C) used in the present invention is based on 100 parts by weight of the (co) polymer (A) having a glass transition point of 0 ° C. or less.
It is generally 0.1 to 40 parts by weight, preferably 0.5 to 30 parts by weight, particularly preferably 1 to 20 parts by weight. When the amount is equal to or more than the lower limit, cracking of the obtained coating film can be prevented, and when the amount is equal to or less than the upper limit, the obtained coating film is smooth and the chipping resistance of the coating is low. This is preferable because it does not decrease.

The aqueous resin composition for coating according to the present invention comprises the above-mentioned (co) polymer (A) having a glass transition point of 0 ° C. or less and a modified inorganic material having a spheroid coefficient of 5 or more and an average particle size of about 1 to 5 μm. In addition to the filler (B), the heat-expandable polymer beads and / or the hollow polymer beads (C), usually other powdered inorganic fillers can be contained.

Examples of such a powdery filler include calcium carbonate, silica, alumina, kaolin, clay, talc, diatomaceous earth, mica, aluminum hydroxide,
Glass powder, barium sulfate, magnesium carbonate and the like can be exemplified. The amount of such a powdery filler used is, for example, 0 to 390 parts by weight, preferably 10 to 380 parts by weight, particularly preferably 20 to 350 parts by weight, based on 100 parts by weight of the (co) polymer (A). Parts. When the amount is not more than the upper limit, it is preferable because the finished appearance of the coating film, the adhesion to a substrate such as a metal processing member, the normal condition and the wet chipping resistance are excellent.

The aqueous resin composition for coating of the present invention may further contain a rust preventive pigment. Examples of the rust-preventive pigment include lead red; metal chromate salts such as zinc chromate, barium chromate and strontium chromate; for example, zinc phosphate, calcium phosphate, aluminum phosphate, titanium phosphate, phosphoric acid Silicon or metal phosphates such as ortho or condensed phosphates of these metals;

For example, metal molybdates such as zinc molybdate, calcium molybdate, zinc calcium molybdate, zinc potassium molybdate, zinc potassium phosphomolybdate, calcium potassium phosphomolybdate; and, for example, calcium borate, zinc borate, borate Metal salts of boric acid such as barium, barium metaborate and calcium metaborate; and the like. Among these rust preventive pigments, it is preferable to use non-toxic or low-toxic rust preventive pigments such as metal phosphates, metal molybdates and metal borates.

The amount of the rust-preventive pigment to be used depends on the amount of the (co) polymer (A) 1
For example, 0 to 50 parts by weight, preferably 5 parts by weight with respect to 00 parts by weight.
It is preferably about 30 parts by weight.

The aqueous resin composition for coating of the present invention further includes, for example, titanium oxide, carbon black, red iron oxide,
An organic or inorganic coloring pigment such as oxide yellow or copper phthalocyanine blue can be contained. The amount of these color pigments used is, for example, 0 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the (co) polymer (A).

The particle size of the powdery filler other than the modified inorganic filler, the rust-preventive pigment and the color pigment is preferably 0.5 to 50 μm from the viewpoint of the smoothness of the formed film of the obtained composition.
In particular, it is preferably about 1 to 30 μm.

The total amount of the modified inorganic filler, the powder filler, the rust preventive pigment and the coloring pigment used in the coating aqueous resin composition of the present invention is based on 100 parts by weight of the (co) polymer (A). Thus, it is preferably, for example, about 60 to 400 parts by weight.

The aqueous coating resin composition of the present invention may further comprise, if necessary, a water-soluble polyvalent metal salt; an aziridine compound;
A crosslinking agent such as a water-soluble epoxy resin; a blocked isocyanate compound; and the like can be contained.

Examples of the above water-soluble polyvalent metal salts include zinc salts such as zinc acetate, zinc formate, zinc sulfate, and zinc chloride; aluminum salts such as aluminum acetate, aluminum nitrate, and aluminum sulfate; Calcium salts such as calcium iodate, calcium chloride, calcium nitrate, calcium nitrite;

For example, barium salts such as barium acetate, barium chloride and barium nitrite; for example, magnesium salts such as magnesium acetate, magnesium formate, magnesium chloride, magnesium sulfate, magnesium nitrate and magnesium nitrite; for example, lead acetate and formic acid Lead salts such as lead;

For example, nickel salts such as nickel acetate, nickel chloride, nickel nitrate and nickel sulfate; manganese salts such as manganese acetate, manganese chloride, manganese sulfate and manganese nitrate; for example, copper chloride, copper nitrate and copper sulfate And a metal oxide such as zinc oxide which can be dispersed in a certain amount in a basic aqueous solution.

As the aziridine compound, a reaction product of a polyisocyanate compound and ethyleneimine can be used.

As the above polyisocyanate compound,
Examples which can be used as the urethane resin, that is, an aromatic polyisocyanate compound, an aliphatic polyisocyanate compound, an alicyclic polyisocyanate compound and the like, and a dimer or 3
Adducts of these isocyanates with, for example, divalent or trivalent polyols such as ethylene glycol and trimethylolpropane.

Examples of the water-soluble epoxy resin include glycerol diglycidyl ether.

Examples of the water-dispersible blocked isocyanate include those obtained by adding a volatile low-molecular-weight active hydrogen compound to the polyisocyanate compound, such as trimethylolpropane tolylene diisocyanate methyl ethyl ketoxime adduct.

Examples of such volatile low-molecular-weight active hydrogen compounds include methyl alcohol, ethyl alcohol, n-butyl alcohol, cyclohexyl alcohol,
Aliphatic, alicyclic or aromatic alcohols such as benzyl alcohol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether and phenol;

For example, hydroxy tertiary amines such as dimethylaminoethanol and diethylaminoethanol; ketoximes such as acetoxime and methylethylketoxime; active methylene compounds such as acetylacetone, acetoacetate and malonate;
lactams such as ε-caprolactam; and the like.

The amount of the crosslinking agent used is, for example, from 0 to 10 parts by weight based on 100 parts by weight of the (co) polymer (A) from the viewpoint of suppressing the change with time of the viscosity of the coating composition to be obtained. Preferably, it is about 0.5 to 10, particularly preferably about 1 to 5 parts by weight.

The aqueous resin composition for coating of the present invention may further comprise, if necessary, an inorganic dispersant (eg, sodium hexametaphosphate, sodium tripolyphosphate, etc.), an organic dispersant [eg, Nopcosperse 44C (trade name, polycarbonate) Dispersants such as silicone-based antifoaming agents; for example, thickeners such as polyvinyl alcohol, cellulose-based derivatives, polycarboxylic acid-based resins, and surfactant-based agents. And viscosity improvers; for example, organic solvents such as ethylene glycol, butyl cellosolve, butyl carbitol, and butyl carbitol acetate; anti-aging agents; preservatives and fungicides; ultraviolet absorbers; Can be.

The aqueous resin composition for coating of the present invention is not particularly limited, but generally has a solid content of about 10 to 85% by weight, preferably about 30 to 80% by weight, particularly preferably about 50 to 80% by weight.
80% by weight; pH 7-11, preferably 8-10; viscosity 100,000c
ps or less (B-type rotational viscometer, 25 ° C, 20 RPM), preferably about
5,000-50,000cps.

Examples of the base material of a metal member to which the aqueous resin composition for coating of the present invention can be preferably used include a steel plate; for example, a lead-tin alloy-plated steel plate (tan sheet steel plate), a tin-plated steel plate, aluminum Various types of plated steel plates, such as plated steel plates, lead-plated steel plates, chrome-plated steel plates, and nickel-plated steel plates; coated steel plates, such as electrodeposited coated steel plates;

That is, the coating composition is obtained by forming the above-mentioned base material into various shapes by a sheet metal press or the like, or by welding these as various automobile members, for example, the floor of the floor of an automobile, a tire house, a gasoline. It can be suitably used for coating an electrodeposition-coated surface, a middle-coated surface or an upper-coated surface of the member, such as a tank, a chassis, a suspension front apron, and a rear apron.

For the coating, a conventionally known method can be adopted, and an airless spray coating method is often used.

The dry film thickness of a suitable anti-chipping film which can be formed by using the coating aqueous resin composition of the present invention is preferably about 200 to 800 μm, particularly preferably about 300 to 600 μm. If the film thickness is not more than the upper limit, blisters are not generated in the heating and drying step, and it is preferable.
It is preferable to be at least the lower limit value because the chipping resistance under normal conditions and wetness is excellent.

The coated surface may be dried at room temperature or under heat. Preferably, it is preliminarily dried at a temperature of about 80 ° C. and then heated in a heating oven at a temperature of about 120 to 180 ° C. It is preferable to dry by heating.

[0117]

The following examples, comparative examples and reference examples are given below.
The present invention will be described in more detail. The preparation and test method of the test sample used in the above Examples and Comparative Examples are as follows.

(1) Preparation of Test Specimen After cleaning the surface of a 0.8 × 100 × 200 mm tan sheet steel plate manufactured by Nippon Steel Corporation with a thinner, each sample was dried by airless spray coating. Is coated so as to have a predetermined thickness.
After pre-drying at 15 ° C. for 15 minutes, heat treatment is performed at 120 ° C. for 20 minutes.

(2) Limit thickness of blister The spray coating in the preceding paragraph (1) was carried out by changing the thickness of the dried film, and the maximum thickness without blistering during drying was determined. And

(3) Critical Crack Film Thickness In the spray coating in the preceding paragraph (1), coating was performed by changing the thickness of the dried film, and the maximum film thickness at which cracks did not occur during drying was determined. And

(4) Normal chipping resistance test A test piece obtained by applying a coating so as to have a dry film thickness of about 300 μm in the preceding paragraph (1) was allowed to stand at a constant temperature of about 25 ° C. for 16 hours. Using an office cutter, cut a cross mark line of about 5 cm each with a depth reaching the substrate from the coating surface.

The test piece was fixed upright at an angle of 60 ° with respect to the horizontal plane.
Using a 5 mmφ PVC pipe, the nut (M-6) is dropped continuously at the cross section of the cut line, and the total weight of the dropped nut when the base material is exposed is evaluated.

(5) Wet chipping resistance test A test piece obtained by applying the coating so as to have a dry film thickness of about 300 μm in the previous section (1) was immersed in deionized water at about 40 ° C. for 7 days and then taken out. After wiping off the water, make a cross mark line as in the previous section (3) and leave it at 25 ° C for 3 hours.
A chipping resistance test is performed in the same manner as in the above (3), and the same evaluation is performed.

(6) Low-Temperature Impact Resistance Test In the preceding paragraph (1), the test piece was left under a constant temperature condition of −30 ° C. for 3 hours or more, and then subjected to a DuPont impact test at the same temperature according to JIS K-5400. I do.

The condition at this time is that the tester has a radius of 6.35 ± 0.03.
Attach a shooting die and a pedestal, and sandwich the test piece with the coating surface facing upward, drop a weight of 500 ± 1 g onto the shooting die from a height of 50 cm, and visually observe the degree of damage to the coating surface. Is evaluated according to the following evaluation criteria.

◎ ・ ・ ・ ・ ・ ・ No change at all ○ ・ ・ ・ ・ ・ ・ Slight crack generation △ ・ ・ ・ ・ ・ ・ Many crack generation × ・ ・ ・ ・ ・ ・ Big crack generation

Reference Example 1 250 parts by weight of deionized water was charged into a 2000 ml separable flask equipped with a stirrer, a reflux condenser and a thermometer, and the temperature was raised to 80 ° C. while flowing nitrogen. Next, 233 parts by weight of deionized water and 10 parts by weight of sodium dodecylbenzenesulfonate (ABS) are added to another container and stirred to form a uniform aqueous solution, and 392.5 parts by weight of butyl acrylate (BA) are added thereto.
A monomer mixture obtained by uniformly mixing 92.5 parts by weight of styrene (St) and 15 parts by weight of acrylic acid (AA) was dropped and stirred to prepare a monomer pre-emulsion.

The pre-emulsion and a 5% by weight aqueous solution of ammonium persulfate (APS)
0 parts by weight were continuously added over 3 hours, and then 1 part at the same temperature.
After holding for a while, 4 ml of about 25% by weight aqueous ammonia was added to obtain an acrylic / styrene copolymer emulsion.

In the polymerization, the monomer composition, the solid content of the obtained copolymer emulsion, pH, viscosity, particle size,
Table 1 shows the Tg of the copolymer.

Reference Examples 2 to 3 Acrylic / styrene copolymer emulsions having different Tg were obtained in the same manner as in Reference Example 1 except that the ratio of BA to St was changed. Table 1 shows the monomer composition, solid content, pH, viscosity, particle size, and Tg of the obtained copolymer emulsion in this polymerization.
Shown in

Reference Example 4 An acrylic copolymer was prepared in the same manner as in Reference Example 1 except that 400 parts by weight of BA and 85 parts by weight of methyl methacrylate (MMA) were used instead of 315 parts by weight of BA and 170 parts by weight of St. A combined emulsion was obtained. The monomer composition during this polymerization, the solid content, pH, viscosity, particle size, and Tg of the obtained copolymer emulsion
Are shown in Table 1.

[0132]

[Table 1]

Example 1 Commercially available SBR copolymer latex SN-318 [trade name;
Manufactured by Sumitomo Dow Co .; Tg-10 ° C, viscosity 80 cps, pH 6.4, solid content 48.6% by weight, average particle size 0.25μ] 206 parts by weight (approximately 100 parts by weight in solid content), irregular shaped inorganic filler 80 parts by weight of calcium carbonate "Phi Turbo H" (trade name; manufactured by Pfizer; average particle diameter 1.5 μ, spheroid coefficient 6.7), and "Matsumoto Microsphere" as thermally expandable polymer beads
F-50 "[trade name; manufactured by Matsumoto Yushi Seiyaku Co., Ltd .; water content: about 30% by weight; particle diameter before thermal expansion: 10 to 20 µm; particle diameter after thermal expansion: 30
~ 80μ; softening temperature of shell wall 100 ~ 105 ° C] 3 parts by weight (approx. 2.1 parts by weight of body excluding water, including the weight of organic solvent as a heat-evaporating foaming agent), heavy as powdered inorganic filler Calcium carbonate SL-700 [Product name: Takehara Chemical Industries
Co., Ltd .; average particle diameter 4.5 μ, spheroid coefficient 1.0] 135 parts by weight,

3 parts by weight of carbon black as a coloring pigment, 12 parts by weight of barium metaborate as a rust preventive pigment, and Nopcopers 44C [trade name; manufactured by San Nopco Co., Ltd .;
Polycarboxylic acid type] 2 parts by weight (solid content about 0.88 parts by weight),
Adecanol UH-472 (trade name; manufactured by Asahi Denka Kogyo Co., Ltd .; surfactant) as a thickener 1.5 parts by weight (solid content: about 0.45 parts by weight) and Nopco 8034 as a defoaming agent [trade name; San Nopco Co., Ltd. )) 0.6 parts by weight is uniformly dispersed using a disper,

The proportion of the total pigment (total amount of deformed calcium carbonate, thermally expandable polymer, powdery calcium carbonate, carbon black and barium metaborate) in the dry film of the composition (hereinafter abbreviated as PWC) Of 70% by weight and a solid content of 75.2% by weight.

Various physical property tests were carried out using the obtained aqueous resin composition for coating. The composition of the composition is shown in Table 2, and the measurement results of various physical properties are shown in Table 3.

Examples 2 to 3 and Comparative Example 1 In Example 1, the amount of the modified calcium carbonate was changed or not used, and the amount of the powdered heavy calcium carbonate was adjusted accordingly. In the same manner as in the above, an aqueous resin composition for coating was prepared.

Various physical properties tests were performed using the obtained aqueous resin composition for coating. The composition of the composition is shown in Table 2, and the measurement results of various physical properties are shown in Table 3.

Examples 4 to 6 and Comparative Example 2 The same procedure as in Example 1 was carried out except that the amount of the heat-expandable polymer beads was changed or not used, and the amount of the powdered heavy calcium carbonate was adjusted accordingly. An aqueous resin composition for coating was prepared in the same manner as in Example 1.

Various physical properties tests were carried out using the obtained aqueous resin composition for coating. The composition of the composition is shown in Table 2, and the measurement results of various physical properties are shown in Table 3.

Example 7 In Example 1, instead of using “Matsumoto Microsphere F-50” as the thermally expandable polymer beads,
"Expancel WU ^# 551" [Product name: Nippon Philite
Co., Ltd .; water content about 30% by weight; particle size before thermal expansion about 10 μ;
Particle size of about 40μ after thermal expansion; softening temperature of shell wall 100-140 ° C]
An aqueous resin composition for coating was prepared in the same manner as in Example 1 except that 3 parts by weight (approximately 2.1 parts by weight of a main body excluding water, including the weight of an organic solvent as a heat-evaporating foaming agent) was used.

Various physical property tests were performed using the obtained aqueous resin composition for coating. The composition of the composition is shown in Table 2, and the measurement results of various physical properties are shown in Table 3.

Example 8 Instead of using 3 parts by weight of the heat-expandable polymer beads “Matsumoto Microsphere F-50” in Example 1, hollow polymer beads “Expancel WE ^# 551” were used.
[Product name; manufactured by Nippon Philite Co., Ltd .; moisture content: about 85% by weight;
Particle size about 40μ] 12 parts by weight (approx.
(Parts by weight) and the amount of the powdered heavy calcium carbonate used was adjusted to prepare an aqueous resin composition for coating in the same manner as in Example 1.

Various physical properties tests were performed using the obtained aqueous resin composition for coating. The composition of the composition is shown in Table 2, and the measurement results of various physical properties are shown in Table 3.

Examples 9 to 10 In Example 1, the SBR copolymer latex SN-31 was used.
Instead of using 206 parts by weight (approximately 100 parts by weight of solid content), commercially available SBR-based copolymer latex SN-562 (trade name; manufactured by Sumitomo Dow Co., Ltd .; Tg-40 ° C, viscosity 170 cps, pH 7. 1,
Solid content 52.5% by weight, average particle size 0.16μ] 190 parts by weight (about 100 parts by weight in solid content), or commercially available NBR-based copolymer latex “Nipol 1571” [trade name;
The same as in Example 1 except that Tg-30 ° C, viscosity 20 cps, pH 8.0, solid content 40% by weight, average particle size 0.12μ] 250 parts by weight (about 100 parts by weight in solid content) are used. To produce a coating aqueous resin composition.

Various physical property tests were performed using the obtained aqueous resin composition for coating. The composition of the composition is shown in Table 2, and the measurement results of various physical properties are shown in Table 3.

Examples 11 to 13 and Comparative Example 3 In Example 1, the SBR copolymer latex SN-31 was used.
An aqueous resin composition for coating was prepared in the same manner as in Example 1 except that the copolymer emulsions of Reference Examples 1 to 4 were used instead of using 206 parts by weight (solid content of about 100 parts by weight) of 8.

Various physical properties tests were performed using the obtained aqueous resin composition for coating. The composition of the composition is shown in Table 2, and the measurement results of various physical properties are shown in Table 3.

[0149]

[Table 2]

[0150]

[Table 3]

[0151]

The aqueous resin composition for coating according to the present invention is, for example, an aqueous resin composition for coating such as a mastic paint, a soundproof paint, an anti-vibration paint, and a caulking material. Tank, an aqueous resin composition for coating excellent in chipping resistance used as a coating agent for protecting an outdoor metal processing member such as a suspension,

Even when a thick coating film of, for example, 600 μm or more is formed, this coating does not cause blisters or cracks in the drying process, and the formed film has a thickness of, for example, about 300 μm. The coating is an aqueous resin composition for coating having excellent chipping resistance even when it is relatively thin.

The aqueous resin composition for coating of the present invention comprises:
(Co) polymer of specific glass transition point, deformed inorganic filler,
And comprising thermally expandable polymer beads and / or hollow polymer beads,

As a result, excellent physical properties which cannot be achieved by using a normal aqueous copolymer emulsion, that is, chipping resistance at ordinary temperature and especially when the film is wet; Impact resistance at extremely low temperatures such as ℃; excellent adhesion to metal workpieces; flat and uniform film formation; water resistance; gasoline resistance; balance of properties as a chipping-resistant coating such as soundproofing Can be well combined.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-28269 (JP, A) JP-A-4-142375 (JP, A) JP-A 64-81864 (JP, A) JP-A 64-64 85260 (JP, A) JP-A-4-53878 (JP, A) JP-A-63-172777 (JP, A) JP-A-1-213369 (JP, A) JP-A-63-218774 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) C09D 5/00 C09D 5/08 C09D 109/00-109/10 C09D 133/02-133/16 C09D 201/00

Claims (1)

(57) [Claims] 1. The following (A) to (C), (A) a (co) polymer having a glass transition point of 0 ° C. or less, and (B) a spheroid coefficient of 5 or more.
In the modified inorganic filler having an average particle size of about 1 to 5μ , and
(C) An aqueous resin composition for coating, comprising: heat-expandable polymer beads and / or hollow polymer beads.