JPH06184465A - Aqueous resin composition for coating - Google Patents

Abstract

PURPOSE:To obtain an aqueous resin composition for coating, usable for outdoor metallic worked members of vehicles such as the undersurface of the floor, a tire house, a gasoline tank, a chassis or a suspension of an automobile and having excellent resistance to chipping without causing the blistering or cracking in a coated film in a drying step thereof even when a thick film is formed. CONSTITUTION:This aqueous resin composition for coating comprises a (co)polymer having a specific glass transition point, an inorganic filler of an irregular shape and thermally expandable polymer beads and/or hollow polymer beads.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an aqueous resin composition for coating, for example, mastic paints, soundproof paints, antivibration paints, caulking materials, among others, vehicles, especially floors of automobiles, tire houses, gasoline tanks. A coating water-based resin composition used as a coating material for protecting outdoor metal working members such as chassis and suspension from scratches caused by flying stones, so-called "chipping",

Even when a thick coating film having a thickness of, for example, 600 μ or more is formed, no blisters or cracks are generated in the film during the drying process, and the formed film has a thickness of, for example, about 300 μ. Excellent chipping resistance even when the film is relatively thin, that is, chipping resistance at room temperature (hereinafter sometimes referred to as normal chipping resistance) and chipping resistance when the coating film is wet (hereinafter, Wet chipping resistance); impact resistance at room temperature and extremely low temperature such as -30 ° C (hereinafter sometimes referred to as low temperature impact resistance); excellent adhesion to metal working members; coating film Uniformity and smoothness; water resistance; gasoline resistance; soundproofing; and other properties as a chipping-resistant coating material in a well-balanced manner.
The present invention relates to a coating aqueous resin composition having excellent properties.

More specifically, (co) of a specific glass transition point
The present invention relates to a coating aqueous resin composition comprising a polymer, a modified 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 acrylic emulsion is used as a vehicle and a powdered inorganic substance such as calcium carbonate or talc is used as a water-based chipping-resistant coating agent used for outdoor metal working members of vehicles such as automobiles. A mixture of agents is known. These coating agents are required to maintain the elasticity of the coating from the viewpoint of chipping resistance, so there is a natural limit to the amount of powder filler to be blended,
Further, it is required to have a much thicker film thickness than that of a general coating agent, and for example, it is applied by airless spray coating or the like so that a dry film has a thickness of about 200 to 800 μm.

Generally, in the case of an aqueous coating material, when an attempt is made to form a thick coating having a small content of an inorganic filler, water evaporates at one time during heating and drying, so that the coating is apt to blister, and thus these aqueous coatings are used. In a coating agent for chipping resistance, the balance between the chipping resistance and the anti-blister property of the coating film has been studied as a serious problem to be solved, for example, JP-A-59-75954 and JP-A-62- 230868
Several proposals described in Japanese Patent Laid-Open No. 63-10678 and Japanese Patent Laid-Open No. 63-172777 are known.

However, these proposals do not always sufficiently overcome the above-mentioned problems of the balance between chipping resistance and anti-blistering property of the coating,
Further, it has also been found that there are cases in which the adhesion of the coating film immediately after being wet with water to the metal-working member (hereinafter sometimes referred to as water-resistant adhesion) is reduced.

The inventors of the present invention, as described above, for example, 600
Even when forming a thick film such as μ or more, blistering does not occur in the drying process, and excellent chipping resistance is achieved even when the formed film is, for example, about 300 μ, which is relatively thin for this type of film. Property, in particular, it can exhibit excellent chipping resistance even at an extremely low temperature such as −30 ° C., and further, adhesion to the metal-working member of the base material,
Rust prevention, flat and uniform film formation, water resistant adhesion,
As a result of research to obtain an aqueous chipping-resistant coating material that has excellent properties such as gasoline resistance, cold bending resistance, impact resistance, and soundproofing, a vehicle such as -30
It has been found that these problems can be solved by using a (co) polymer having a glass transition point of about ℃, and by using a deformed inorganic filler such as "gold and rice sugar" as a filler. 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 cracks may occur in the coating film due to rapid drying shrinkage during heating and drying depending on the blending amount of the irregular-shaped inorganic filler. As a result of further studies, it was found that the aqueous coating composition further contained, for example, heat-expandable polymer beads or hollow polymer beads which were expanded by heating at about 110 ° C., It was found that it is possible to obtain an excellent coating aqueous resin composition that can prevent the occurrence of cracks in the coating while maintaining the excellent properties of the aqueous coating composition, and to complete the present invention. I arrived.

[0009]

Means for Solving the Problems The present invention includes the following (A) to
(C), (A) (co) polymer having a glass transition point of 0 ° C. or lower, (B)
It is an object of the present invention to provide an aqueous resin composition for coating, which comprises a modified inorganic filler and (C) heat-expandable polymer beads and / or hollow polymer beads.

The present invention will be described in detail below. The (A) (co) polymer 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 preferably used.

As such a water-dispersible (co) polymer,
Examples thereof include acrylic (co) polymer emulsions and synthetic rubber copolymer latexes. These water-dispersible (co) polymers may be used alone or in admixture of two or more.

The above acrylic (co) polymer emulsions include, for example, the following monomers (a) to (d) and (a)
(1)

[0013]

[Chemical 1]

(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) acrylic acid ester type monomer selected from (b) 0 to 5% by weight of an ethylene type monomer having 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, and a monomer other than the above monomer (b) 0 to 15% by weight , (D) the monomers (a) to (c) and copolymerizable with the monomers (a) to (c)
Other monomers 0 to 50% by weight (however, monomers (a) to (d)
Of 100% by weight) is aqueous emulsion polymerized
An example is a (co) polymer emulsion.

In the monomer (a) represented by the above general formula (1), R ¹ is H or a methyl group and R ² has 1 carbon atom.
Examples thereof include alkyl ester monomers of acrylic acid or methacrylic acid represented by straight chain or branched alkyl groups of 20 to 20.

In these monomers, when R ¹ is H, that is, in the case of an acrylic acid ester-based monomer, R ² is a carbon number from the viewpoint of availability and polymerization reaction. 1 to 1
It is preferably 0 straight-chain or branched alkyl groups.
Examples of such an alkyl group include, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 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 methacrylic acid ester-based monomer, R ² has a carbon number of 1 to 1 for the same reason as in the case of the acrylic acid ester-based monomer. It is preferably a linear or branched alkyl group of 15, and 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, and an i-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, n-dodecyl group, t-dodecyl group, and the like,

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

The amount of the above-mentioned monomer (a) alkyl ester monomer of acrylic acid or methacrylic acid is
Generally from 30 to 100% by weight, preferably from 42 to 99.5% by weight, particularly preferably from 52 to 9%, based on 100% by weight of the total of (a) to (d).
It should be 9.5% by weight. When the amount of the monomer (a) used is at least the lower limit value, it is preferable during the aqueous emulsion polymerization since problems such as generation of aggregates and destruction of the emulsified state do not occur, while the upper limit value is set. When it is below, the resulting copolymer emulsion does not deteriorate in mechanical stability and storage stability, and also the adhesion of the obtained coating aqueous resin composition to a substrate such as a metal-working member is improved. It is preferable because it is excellent.

Examples of the ethylene-based monomer having a carboxyl group in the molecule (hereinafter sometimes referred to as a carboxyl group-containing monomer) (b) include acrylic acid,
C3 to C5 α, β-unsaturated mono- or di-carboxylic acids such as methacrylic acid, crotonic acid, citraconic acid, itaconic acid, maleic acid and fumaric acid (hereinafter abbreviated as ethylene-based carboxylic acid A); for example, an anhydride of an α, β-unsaturated dicarboxylic acid having 4 to 5 carbon atoms such as maleic anhydride;

For example, mono-n-butyl maleate, mono-n-
Butyl fumarate, monoethyl itaconate and other C4 to C5 α, β-unsaturated dicarboxylic acid C1 to C12 monoalkyl ester monomers; for example, ethylene acrylate and ammonium methacrylate Examples thereof include an ammonium salt or an alkali metal salt of a carboxylic acid or an α, β-unsaturated dicarboxylic acid monoalkyl ester monomer 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, the less generation of aggregates, and the like, and the use of acrylic acid, methacrylic acid, and / or itaconic acid is particularly preferred.

The amount of the above-mentioned 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 100% by weight of the total of (d). If the amount of the monomer (b) used is not more than the above upper limit, the occurrence of aggregates during the aqueous emulsion polymerization or the destruction of the emulsified state, or the storage stability of the resulting emulsion may be reduced. It is preferable because it does not exist. On the other hand, when the amount used is 0.5% by weight or more, the generation of aggregates during aqueous emulsion polymerization is suppressed, the mechanical stability of the obtained copolymer emulsion is improved, and the obtained aqueous coating resin composition is used. It is preferable because it has excellent adhesion to a substrate such as a metal-worked member.

The above-mentioned monomer (c) is a monomer having at least one functional group in the molecule in addition to one radical-polymerizable unsaturated group, and is different from the above-mentioned monomer b. A monomer, and examples of such a monomer include acrylamide, methacrylamide, diacetone acrylamide, and 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;

For example, esters of ethylene-based carboxylic acids such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate with polyvalent saturated alcohols; for example, dimethylaminoethyl methacrylate. , Esters of ethylene-based carboxylic acids such as diethylaminoethyl methacrylate and saturated alcohols 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 and the like. A monomer having a radically polymerizable unsaturated group;
And the like.

The amount of these monomers (c) used is from the monomers (a) to
The total amount of (d) is preferably 0 to 15% by weight based on 100% by weight. When the amount used is 15% by weight or less, problems such as generation of aggregates and destruction of the emulsified state during aqueous emulsion polymerization, or deterioration of storage stability of the resulting aqueous dispersion do not occur, which are preferable. .

Furthermore, the monomer (d) is a monomer copolymerizable with the monomers (a) to (c) and 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; , Vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate, etc., saturated fatty acid vinyl monomers having 1 to 12 carbon atoms; for example, dibutyl malate,
Dioctyl malate, dibutyl fumarate, dioctyl fumarate, dibutyl itaconate, dioctyl itaconate, etc., such as unsaturated α, β-dicarboxylic acid C 1-12 dialkyl ester monomers; Mentor groups can be mentioned.

The amount of the comonomer (d) used is generally 0 to 5 with respect to 100% by weight of the total of the monomers (a) to (d).
0% by weight, preferably 0-40% by weight, particularly preferably 0
It is about 30% by weight.

As the "(aqueous) emulsion polymerization (co) polymer emulsion" which can be used in the present invention, the monomer groups (a) to (d) are present in the presence of a surfactant and / or a protective colloid. The (co) polymer emulsion obtained by emulsion polymerization in an aqueous medium can be exemplified below.

Examples of the above-mentioned surfactants include nonionic surfactants such as polyoxyalkylene alkyl (or alkenyl) ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; for example, polyoxyethylene octylphenol. Polyoxyalkylene alkylphenol ethers such as ether and polyoxyethylene nonylphenol ether;

For example, sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate and other sorbitan fatty acid esters; for example, polyoxyethylene sorbitan monolaurate and other polyoxyalkylene sorbitan fatty acid esters; for example, polyoxyethylene 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 copolymers;
Etc. can be mentioned.

Examples of the anionic surfactants include:
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; sodium monooctylsulfosuccinate Alkyl sulfosuccinate salts such as dioctyl sodium sulfosuccinate and polyoxyethylene lauryl sodium sulfosuccinate, and derivatives thereof;

Examples thereof include polyoxyalkylene alkyl ether sulfuric acid ester salts such as polyoxyethylene lauryl ether sulfuric acid sodium salt; for example, polyoxyalkylene alkyl aryl ether sulfuric acid ester salts such as polyoxyethylene nonylphenol ether sulfuric acid sodium salt; and the like. .

Examples of the cationic surfactants include alkylamine salts such as laurylamine acetate;
For example, lauryl trimethyl ammonium chloride,
Examples of amphoteric surfactants include quaternary ammonium salts such as alkylbenzyldimethylammonium chloride; for example, polyoxyethylalkylamine; and alkylbetaines such as laurylbetaine.

Further, it is also possible to use those obtained by substituting a part of hydrogen atoms of the alkyl group of these surfactants with fluorine. Further, a so-called reactive surfactant having a radical copolymerizable unsaturated bond in the molecular structure of these surfactants can also be used.

Among these surfactants, nonionic surfactants include polyoxyalkylene alkyl ethers and polyoxyalkylene alkyl phenol ethers; from the viewpoint of less generation of aggregates during emulsion polymerization. As the ionic surfactants, alkyl aryl sulfonates; alkyl sulfates; alkyl sulfosuccinic acid ester salts and derivatives thereof; polyoxyalkylene alkyl ether sulfuric acid ester salts; polyoxyalkylene alkyl phenol ether sulfuric acid ester salts; preferable. These surfactants may be used alone or in appropriate combination.

The amount of these surfactants used is usually about 100 parts by weight based on 100% by weight of the monomers (a) to (d).
0.5 to 10 parts by weight, the polymerization stability of the aqueous emulsion polymerization,
From the viewpoint of storage stability of the (co) polymer emulsion and excellent adhesion to a substrate such as a metalworking member when used as the aqueous resin composition for coating 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 that can be used in the acrylic (co) polymer emulsion used in the present invention include polyvinyl alcohols such as partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol and modified polyvinyl alcohol; Cellulose derivatives such as hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose salt; and natural polysaccharides such as guar gum; The amount of these protective colloids used is, for example, a total of 10 of the monomers (a) to (d).
It is preferably about 0 to 3 parts by weight with respect to 0 parts by weight.

In emulsion polymerization, as a polymerization initiator,
For example, persulfates such as ammonium persulfate, potassium persulfate and ammonium persulfate; organic peroxides such as t-butyl hydroperoxide, cumene hydroperoxide and p-menthane hydroperoxide; hydrogen peroxide; They can be used alone or in combination of two or more. The amount used can be appropriately selected, but is, 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, it is about 0.1 to 0.5 parts by weight.

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

Furthermore, a chain transfer agent can be optionally used in the emulsion (co) polymerization. Examples of such a chain transfer agent include cyanoacetic acid; cyanoacetic acid having 1 to 8 carbon atoms; bromoacetic acid; bromoacetic acid having 1 to 8 carbon atoms; anthracene, phenanthrene, fluorene, 9-phenyl Aromatic compounds such as fluorene; p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol, aromatic nitro compounds such as 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; 1 to 1 carbon atoms of mercaptoacetic acid And the like. 10 alkyl esters; C1-C12 hydroxyalkyl mercaptans; terpenes such as binene and terpinolene; and the like.

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

The polymerization temperature is generally about 30 to 100 ° C,
It is preferably in the range of about 40 to 90 ° C.

The acrylic (co) polymer emulsion used in the present invention is not particularly limited, but in general,
The solid content is about 10 to 70% by weight, the pH is 2 to 10 and the viscosity is 10000 cps or less (B type rotational viscometer, 25 ° C, 20RPM), and the solid content is about 30 to 65% by weight due to the ease of production and good productivity. (Particularly about 40 to 60% by weight), pH 2 to 8 and viscosity of about 50 to 5000 cps are preferable.

Ammonia water, water-soluble amines, aqueous solutions of alkali hydroxides, etc. can be used as the pH regulator.

Further, the acrylic type (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.degree. If the Tg of the (co) polymer exceeds the upper limit and is too high, the low-temperature impact resistance of the obtained aqueous resin composition for coating may decrease, which is not preferable. On the other hand, when it is at least the lower limit value, the film strength of the coating composition does not decrease, and the normal state and wet chipping resistance are excellent, which is preferable.

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

Glass transition point: In a cylindrical cell made of an 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,
Weigh out about 10 mg of (co) polymer emulsion sample, and measure at 100 ℃
The sample dried for 2 hours is used as a measurement sample. A differential scanning calorimeter [Differential Scanning Calorimeter: SSC-5000 type manufactured by Seiko Denshi Kogyo Co., Ltd.] is used to measure and determine from -150 ° C at a heating rate of 10 ° C / min.

Further, the acrylic (co) polymer (A) of the present invention
Generally has a weight average molecular weight of 500,000 or more, particularly 800,000 or more. The average particle size of the acrylic (co) polymer emulsion dispersed particles (hereinafter, sometimes simply referred to as particle size) is generally 0.05 to 0.5 µ, and particularly preferably 0.1 to 0.3 µ. When the particle diameter is not more than the upper limit value, sedimentation, separation and the like are less likely to occur even when the obtained coating aqueous resin composition is stored for a long time, which is preferable. On the other hand, when it is at least the lower limit value, no agglomerates or emulsion breakage occurs during emulsion polymerization of the emulsion, which is preferable.

The particle size of the acrylic (co) polymer (A) is determined by the Chemical Society of Japan "New Experimental Chemistry Course 4 Basic Technology 3 Light".
(II) ”pp. 725-741 [Published by Maruzen Co., Ltd. on July 20, 1976]
It is a value measured by the DLS method described in 1. and specifically a value determined by the method described below. Average particle size: Dilute an aqueous dispersion such as (co) polymer emulsion by 50,000 to 150,000 times with distilled water, mix thoroughly with stirring, and collect about 10 ml using a Pasteur pipette in a 21 mmφ glass cell. Then, this is a dynamic light scattering photometer DLS-700
It is set at a predetermined position of [Otsuka Electronics Co., Ltd.] and measured under the following measurement conditions.

Measurement conditions Measurement temperature 25 ± 1 ℃ Clock rate 10μsec Correlation channel (Corel. Channel) 512 Total number of measurements 200 times Light scattering angle 90 ° Average particle 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. Examples thereof include those obtained by subjecting monomers to aqueous emulsion copolymerization under elevated pressure.

Examples of the conjugated diolefin-based monomer include butadiene, isoprene, chloroprene and the like. The amount of these conjugated diolefin-based monomers used is 100% by weight in total of the monomer components constituting the synthetic rubber.
On the other hand, it is generally 20 to 75% by weight, preferably 30 to 50% by weight. If the amount used is below the upper limit,
It is preferable because the coating strength of the resulting aqueous resin composition for coating using the synthetic rubber-based copolymer latex does not decrease. On the other hand, when it is at least the lower limit value, the base material for metal working members of the composition. It is preferable because the adhesiveness to

Examples of the aromatic vinyl monomer and the vinyl cyanide monomer include the aromatic vinyl monomer and the vinyl cyanide monomer which are exemplified as the monomer (c) in the acrylic (co) polymer emulsion. Body, eg, styrene, α-methylstyrene, vinyltoluene, ethylvinylbenzene, etc .; and, eg, acrylonitrile,
Methacrylonitrile and the like;

The amount of the above-mentioned 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. It is preferably 40 to 70% by weight. When the amount used is at least the lower limit value, the film strength of the resulting coating aqueous resin composition using the synthetic rubber-based latex will not be lowered, which is preferable. It is preferable because the film forming property of the product is excellent and the adhesiveness to the base material such as the metal-working member does not decrease.

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

Examples of these comonomers include acrylic acid or methacrylic acid ester monomers represented by the general formula (1), which are exemplified as the monomer (a) in the acrylic (co) polymer emulsion; Monomers in emulsion
Carboxyl group-containing monomer exemplified as (b); Ethylene carboxylic acid amides or derivatives thereof exemplified as the monomer (c) in the emulsion, of ethylene carboxylic acid and saturated alcohol having an epoxy group Examples thereof include esters and esters of ethylene-based carboxylic acids and polyhydric saturated alcohols.

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

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

The usable surfactants and protective colloids are nonionic surfactants, anionic surfactants, and cationic surfactants that 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, and their amounts used are almost the same as the amounts used in the production of the emulsion.

Further, a polymerization initiator, a reducing agent, a chain transfer agent,
As the pH adjusting agent and the like, the same ones as those which can be placed 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.degree. If the glass transition point of the (co) polymer exceeds the upper limit and is too high, the resulting coating aqueous resin composition may have poor chipping resistance at extremely low temperatures, which is not preferable. When it is at least the lower limit, the coating strength of the coating composition does not decrease, and the normal state and wet chipping resistance are excellent, which is preferable.

Further, it is desirable that the synthetic rubber-based copolymer generally has a gel fraction within the range of 60 to 98% by weight, particularly 70 to 95% by weight.

The gel fraction of the synthetic rubber copolymer is
It is a value obtained by measuring by the following method.

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

Further, the particle size of the synthetic rubber-based copolymer latex dispersed particles is generally 0.05 to 0.5 μ, particularly 0.1.
It is desirable to be in the range of ~ 0.3μ.

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-based 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 [above, Sumitomo Dow Co., Ltd.], SK-80 [Takeda Pharmaceutical Co., Ltd.], L-200
1, L2337 [above, Asahi Kasei Corp.], Polylac 707
Styrene-butadiene synthetic rubber latex (hereinafter sometimes abbreviated as SBR) sold under the trade name of [Mitsui Toatsu Chemicals, Inc.]; Nipol 1571, Nipol 1551,
Examples thereof include acrylonitrile-butadiene synthetic rubber latex (hereinafter sometimes abbreviated as NBR) marketed under the trade name of Nipol 1562 [above, manufactured by Nippon Zeon Co., Ltd.] and the like.

The coating aqueous resin composition of the present invention comprises the modified inorganic filler (B) together with the (co) polymer (A) having a glass transition point of 0 ° C. or lower as described above. .
In the above-mentioned modified inorganic filler, the "modified" means, for example, "
A shape having an extremely large specific surface area, such as a "rice-rice sugar" shape, having a convex surface. The following formula (2),

[0073]

[Equation 1]

It is preferable that the spherical coefficient defined by is 5 or more. When the spherical coefficient is 5 or more, blisters can be prevented from being generated when a relatively thick coating film of the aqueous coating resin composition is formed, and the resulting coating film has excellent chipping resistance.

The average particle size of the inorganic filler is about 1 to
It is preferably 5μ. If the average particle size is 1 μm or more, the workability when applying the coating composition is excellent, and if it is 5 μm or less, the coating resistance of the resulting coating aqueous resin composition is significantly improved. Therefore, it is preferable.

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

The amount of the modified inorganic filler used is
(Co) with respect to 100 parts by weight of the polymer, for example, 10 to 400 parts by weight,
It is preferably 20 to 300 parts by weight, particularly preferably 30 to 200 parts by weight. When the amount used is less than or equal to the upper limit, it is preferable because the finished appearance of the coating film using the obtained composition is excellent, and the adhesion to a substrate such as a metalworking member is excellent. When it is at least the lower limit value, the resulting coating has excellent chipping resistance, which is preferable.

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

The above-mentioned heat-expandable polymer beads are obtained by encapsulating a heat vaporizing type foaming agent or a heat decomposing type 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 softens at the heating temperature when forming a coating film using the obtained coating aqueous resin composition, but is, for example, 60 to 130. It is preferable to use a resin which softens at 70 ° C., particularly about 70 to 120 ° C., for example, vinyl resins such as polyolefin, polyacrylonitrile, polyacrylate, polystyrene, polyvinyl chloride, polyvinylidene chloride and copolymers thereof; polyester. resin;
Examples of the thermoplastic resin include a silicone resin; a thermoplastic urethane resin;

Examples of the heat vaporizing type foaming agent include boiling point-
It is possible to use organic solvents such as hydrocarbons, halogenated hydrocarbons, esters, ethers, and ketones, which have a low boiling point of about 50 to + 50 ° C.

Further, as the heat decomposition type foaming agent, for example,
Nitroso compounds such as N, N'-dinitrosopentamethylenetetramine and N, N'-dimethyl-N, N'-dinitrosoterephthalamide; for example, azo compounds such as azodicarbonamide;
For example, sulfonyl hydrazide compounds such as benzenesulfonyl hydrazide, p, p'-oxybis (benzenesulfonylamide), benzene-1,3-disulfonyl hydrazide, toluenesulfonyl hydrazide and their derivatives; p-toluenesulfonyl semicarbazide; trihydrazinotriazine , Etc. can be mentioned.

These heat-expandable polymer beads have a heat expansion temperature of, for example, 60 to 180 ° C., particularly 7
It is about 0 to 160 ° C., and various stability before and after thermal expansion, excellent in safety, and easily available are good, and a vinyl resin such as acrylonitrile-vinylidene chloride copolymer is used as a shell wall. It is particularly preferable that a hydrocarbon-based organic solvent such as isobutane is included as a heating vaporization type foaming agent.

Further, the heat-expandable polymer beads have an average particle diameter before thermal expansion of 1 to 50 μ, particularly about 3 to 40 μ, and an average particle diameter after thermal expansion of 5 to 300.
It is preferably μ, and particularly preferably about 20 to 200 μ.

Examples of the heat-expandable polymer beads that can be preferably used in the present invention include Matsumoto Microspheres F-30 and F-50 [above, manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.], EXPAN. Cell WU ^# 642, WU ^# 551, WU ^# 46
1, DU ^# 551, DU ^# 461, DU ^# 051 (above, Japan Philite
Manufactured by K.K., etc. can be mentioned.

Some of these heat-expandable polymer beads are commercially available in the form of so-called "wet cake" containing water for the reason of easy handling, and the above-mentioned "Matsumoto Microsphere F". -30, F-50 "and" Expansell WU # 642, WU ^# 551, WU ^# 461 "are this type.

The hollow polymer beads which can be used in the present invention are the same as those in the above-mentioned heat-expandable polymer beads, for example, polyolefin, polyacrylonitrile, polyacrylate, polystyrene, polyvinyl chloride, polyvinylidene chloride and these Examples thereof include those having a shell wall made of a thermoplastic resin such as a copolymer; a polyester resin; a silicone resin; a thermoplastic urethane resin. For example, the heat-expandable polymer beads are preliminarily thermally expanded under appropriate heating conditions. What can be used suitably. In addition to these, those using a thermosetting resin such as an amino resin, a phenol resin, 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 μ, preferably about 5 to 300 μ.

Hollow polymer beads that can be preferably used in the present invention include, for example, Expancel DE ^#
551, WE ^# 551 [above, manufactured by Nippon Philite Co., Ltd.] and the like are commercially available. Some of these hollow polymer beads are commercially available as so-called "wet cake" containing water for reasons such as ease of handling, as in the case of the above-mentioned heat-expandable polymer beads, "Expansell WE ^# 551" is this type.

The heat-expandable polymer beads and / or hollow polymer beads (C) used in the present invention are used in an amount of 100 parts by weight of (co) polymer (A) having a glass transition point of 0 ° C. or lower.
Generally, it is 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 used is at least the lower limit value, cracking of the obtained coating film can be prevented, and when it is at most the upper limit value, the obtained coating film is smooth and the chipping resistance of the coating film is high. It is preferable because it does not decrease.

The aqueous resin composition for coating of the present invention comprises a (co) polymer (A) and a modified inorganic filler (B) having a glass transition point of 0 ° C. or less, heat-expandable polymer beads and / or hollow particles. Other powdery inorganic fillers can be usually contained together with the polymer beads (C).

Examples of such powdery fillers include calcium carbonate, silica, alumina, kaolin, clay, talc, diatomaceous earth, mica, aluminum hydroxide,
Examples thereof include glass powder, barium sulfate, magnesium carbonate and the like. The amount of such 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, relative to 100 parts by weight of the (co) polymer (A). It should be about a copy. When the amount used is less than or equal to the upper limit, the finished appearance of the coating film, the adhesion to a substrate such as a metalworking member, the normal state and the resistance to wet chipping are excellent, and therefore it is preferable.

The coating aqueous resin composition of the present invention may further contain a rust preventive pigment. Examples of the rust-preventive pigment include red lead; for example, metal chromates 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, and potassium potassium phosphomolybdate; for example, calcium borate, zinc borate, boric acid. Examples thereof include metal salts of boric acid such as barium, barium metaborate, 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 phosphate, metal molybdate, and metal borate.

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

Further, the aqueous resin composition for coating of the present invention may be, for example, titanium oxide, carbon black, rouge,
Organic or inorganic color pigments such as oxide yellow and 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, based on 100 parts by weight of the (co) polymer (A).

The particle diameters of the powdery filler, the rust preventive pigment and the coloring pigment other than these irregularly shaped inorganic fillers are 0.5 to 50 μm from the viewpoint of the smoothness of the film formed of the composition obtained.
It is particularly 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 aqueous resin composition for coating of the present invention is 100 parts by weight of the (co) polymer (A). For example, it is preferably about 60 to 400 parts by weight.

The coating aqueous resin composition of the present invention may further contain a water-soluble polyvalent metal salt; an aziridine compound;
A cross-linking agent such as a water-soluble epoxy resin; a blocked isocyanate compound;

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 formate, calcium chloride, calcium nitrate and calcium nitrite;

For example, barium salts such as barium acetate, barium chloride, barium nitrite; magnesium salts such as magnesium acetate, magnesium formate, magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium nitrite; lead acetate, formic acid, etc. Lead salt such as lead;

For example, nickel salts such as nickel acetate, nickel chloride, nickel nitrate, nickel sulfate; manganese salts such as manganese acetate, manganese chloride, manganese sulfate, manganese nitrate; copper chloride, copper nitrate, copper sulfate, etc. And the like, and metal oxides such as zinc oxide which can be dispersed to some extent in a basic aqueous solution can also be used.

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

As the above polyisocyanate compound,
Examples of the urethane resin that can be used include aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds and alicyclic polyisocyanate compounds, and dimers or 3 of these isocyanates.
Polymers: Adducts of these isocyanates with divalent or trivalent polyols such as ethylene glycol and trimethylolpropane can be exemplified.

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 above polyisocyanate compound, such as trimethylolpropane tritolylene 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, acetoacetic acid ester, malonic acid ester and the like;
lactams such as ε-caprolactam; and the like.

The amount of these cross-linking agents used is, for example, from 0 to 10 parts by weight, relative to 100 parts by weight of the (co) polymer (A), from the viewpoint of suppressing the change with time of the viscosity of the obtained coating composition. It is preferably 0.5 to 10, particularly preferably 1 to 5 parts by weight.

The aqueous resin composition for coating of the present invention may further comprise an inorganic dispersant (eg, sodium hexametaphosphate, sodium tripolyphosphate, etc.), an organic dispersant (eg, Nopcospers 44C (trade name, polycarboxylic acid), if necessary. Acid-based; San Nopco Ltd.) and the like]; for example, silicone-based defoaming agents; for example, polyvinyl alcohol, cellulose-based derivatives, polycarboxylic acid-based resins, surfactant-based thickeners, etc. And a viscosity improver; for example, an organic solvent such as ethylene glycol, butyl cellosolve, butyl carbitol, butyl carbitol acetate; an antiaging agent; an antiseptic / antifungal agent; an ultraviolet absorber; an antistatic agent; You can

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 50% by weight.
80% by weight; pH 7-11, preferably 8-10; viscosity 100,000c
ps or less (B type rotational viscometer, 25 ° C, 20RPM), preferably about
It is 5,000 to 50,000 cps.

Examples of the base material of the metalworking member for which the aqueous resin composition for coating of the present invention can be preferably used include steel plates; for example, lead-tin alloy-plated steel plates (tan sheet steel plates), tin-plated steel plates, and aluminum. Examples thereof include various plated steel sheets such as plated steel sheets, lead-plated steel sheets, chrome-plated steel sheets and nickel-plated steel sheets; coated steel sheets such as electrodeposition coated steel sheets.

That is, the coating composition is obtained by molding the above-mentioned base material into various shapes by a sheet metal press or the like, and welding these as various automobile members, for example, under floor of automobile, tire house, 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.

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

The dry film thickness of a suitable chipping-resistant coating that can be formed using the aqueous coating resin composition of the present invention is preferably about 200 to 800 µ, and more preferably about 300 to 600 µ. If the film thickness is less than or equal to the upper limit, blistering does not occur in the heating and drying step, which is preferable.
When it is at least the lower limit value, the normal state and wet chipping resistance are excellent, which is preferable.

The coated surface may be dried at room temperature or by heating, but preferably, it is pre-dried at a temperature of about 80 ° C. and then heated in a heating furnace at a temperature of about 120 to 180 ° C. It is better to heat dry.

[0117]

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

(1) Preparation of test piece After cleaning the surface of 0.8 × 100 × 200 mm tan sheet steel sheet manufactured by Nippon Steel Co., Ltd. with a thinner, each sample was coated with a dry film by an airless spray coating method. It is painted to a thickness of 80 ° C, predried at 80 ° C for 15 minutes using a hot air circulation dryer, and then heat treated at 180 ° C for 20 minutes.

(2) Blister limit film thickness In spray coating in the previous section (1), the dry film thickness is changed to obtain the maximum film thickness without blistering during drying. And

(3) Crack limit film thickness In spray coating in the above item (1), the dry film thickness is changed to perform coating, and the maximum film thickness that does not cause cracks during drying is determined. And

(4) Normal-state chipping resistance test In the previous item (1), a test piece obtained by coating so as to have a dry film thickness of about 300 μ was left for 16 hours under a constant temperature condition of about 25 ° C. Using an office cutter, make a cut line with a mark of x each having a depth of about 5 cm from the coating surface to the substrate.

The test piece was fixed by leaning against the horizontal plane at an angle of 60 °, and the coated surface was vertically moved from a height of 2 m to a vertical direction of 2 m.
Using a 5 mmφ PVC pipe, drop the nut (M-6) continuously toward the cross part of the cut line, and evaluate the total weight of the dropped nut when the base material is exposed.

(5) Wet chipping resistance test In the previous item (1), a test piece obtained by coating so as to have a dry film thickness of about 300 μ was immersed in deionized water at about 40 ° C. for 7 days and then taken out. Wipe off the water and then make a cut line with a cross like the previous (3) item, leave it at 25 ° C for 3 hours,
A chipping resistance test is carried out in the same manner as in the previous item (3) and evaluated in the same manner.

(6) Low temperature impact resistance test In the previous item (1), the test piece was left for 3 hours or more under the constant temperature condition of -30 ° C, and then at the same temperature according to JIS K-5400, the DuPont type impact resistance test. I do.

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

◎ ・ ・ No change at all ○ ・ ・ ・ ・ ・ ・ Slightly small cracks were generated △ ・ ・ ・ ・ Small cracks were generated × ・ ・ ・ Large cracks were generated

Reference Example 1 A 2000 ml separable flask equipped with a stirrer, a reflux condenser and a thermometer was charged with 250 parts by weight of deionized water, 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) were placed in another container and stirred to form a uniform aqueous solution, and 392.5 parts by weight of butyl acrylate (BA) were added thereto.
92.5 parts by weight of styrene (St) and 15 parts by weight of acrylic acid (AA) were uniformly mixed, and a monomer mixture liquid was dropped and stirred to prepare a monomer pre-emulsion.

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

The monomer composition in this polymerization, 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 In the same manner as in Reference Example 1, except that the use ratio of BA and St was changed, acrylic / styrene copolymer emulsions having different Tg were obtained. Table 1 shows the monomer composition, the solid content of the obtained copolymer emulsion, the pH, the viscosity, the particle size, and the Tg of the copolymer during 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. Monomer composition during the polymerization, solid content of the obtained copolymer emulsion, pH, viscosity, particle size, and Tg of the copolymer
Is shown in Table 1.

[0132]

[Table 1]

Example 1 Commercially available SBR-based copolymer latex SN-318 [trade name;
Sumitomo Dow Co., Ltd .; Tg-10 ° C., viscosity 80 cps, pH 6.4, solid content 48.6% by weight, average particle size 0.25 μ] 206 parts by weight (solid content about 100 parts by weight), modified as a modified inorganic filler Calcium carbonate "Phi Turbo H" [trade name; manufactured by Pfizer Inc .; average particle size: 1.5μ, spherical coefficient: 6.7] 80 parts by weight, "Matsumoto Microspheres" as heat-expandable polymer beads
F-50 ”[trade name; manufactured by Matsumoto Yushi-Seiyaku Co., Ltd .; water content: about 30% by weight; particle size before thermal expansion: 10 to 20 μ; particle size after thermal expansion: 30]
~ 80μ; softening temperature of shell wall 100 ~ 105 ° C] 3 parts by weight (main body weight excluding water, about 2.1 parts by weight, including the weight of organic solvent as a heating vaporizing type foaming agent), heavy as a powdery inorganic filler Quality calcium carbonate SL-700 [trade name; Takehara Chemical Industry
Co., Ltd .; average particle size 4.5μ, sphere 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 an anticorrosion pigment, Nopco Perth 44C as a dispersant [trade name; manufactured by San Nopco Ltd .;
Polycarboxylic acid type] 2 parts by weight (solid content: about 0.88 parts by weight),
Adekanol UH-472 [trade name; manufactured by Asahi Denka Kogyo Co., Ltd .; surfactant system] 1.5 parts by weight (solid content: about 0.45 parts by weight) as a thickener and Nopco 8034 [trade name; San Nopco (stock) as a defoaming agent. )) 0.6 parts by weight are evenly dispersed using a disper,

Ratio of total pigment (total amount of modified calcium carbonate, heat-expandable polymer, powdered ground 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 to prepare an aqueous resin composition for coating.

Various physical property tests were carried out using the obtained coating aqueous resin composition. 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 and 3 and Comparative Example 1 Example 1 is the same as Example 1 except that the amount of modified calcium carbonate used is changed or not used, and the amount of powdered heavy calcium carbonate used is adjusted accordingly. An aqueous resin composition for coating was prepared in the same manner as in.

Various physical property tests were conducted using the obtained coating aqueous resin composition. 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 Example 1 was repeated except that the amount of the heat-expandable polymer beads was changed or not used, and the amount of the powdered ground calcium carbonate was adjusted accordingly. An aqueous resin composition for coating was prepared in the same manner as in Example 1.

Various physical property tests were carried out using the obtained coating aqueous resin composition. 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 Instead of using "Matsumoto Microsphere F-50" as the heat-expandable polymer beads in Example 1,
"Expansell WU ^# 551" [Product name: Nippon Philite
Co., Ltd .; water content about 30% by weight; particle size before thermal expansion about 10μ;
Particle diameter after thermal expansion of about 40μ; softening temperature of shell wall 100-140 ℃
An aqueous resin composition for coating was prepared in the same manner as in Example 1 except that 3 parts by weight (main body weight excluding water, about 2.1 parts by weight, including the weight of the organic solvent as the heat-vaporizable foaming agent) was used.

Various physical property tests were carried out using the obtained coating aqueous resin composition. 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 thermally expandable polymer beads "Matsumoto Microsphere F-50" in Example 1, hollow polymer beads "Expancel WE ^# 551" are used.
[Brand name: manufactured by Nippon Philite Co., Ltd .; moisture content of about 85% by weight;
Particle size: about 40μ] 12 parts by weight (body weight excluding water is about 1.8
(Part by weight), and an aqueous resin composition for coating was prepared in the same manner as in Example 1 except that the amount of the powdered heavy calcium carbonate used was adjusted.

Various physical property tests were conducted using the obtained coating aqueous resin composition. 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, SBR copolymer latex SN-31 was used.
Instead of using 206 parts by weight of 8 (about 100 parts by weight in terms of solid content), a commercially available SBR 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 (solid content about 100 parts by weight), or commercially available NBR copolymer latex "Nipol 1571" [trade name; Nippon Zeon
Co., Ltd .; Tg-30 ° C., viscosity 20 cps, pH 8.0, solid content 40% by weight, average particle size 0.12 μ] 250 parts by weight (solid content of about 100 parts by weight) as in Example 1 Then, an aqueous resin composition for coating was prepared.

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 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 of 8 (about 100 parts by weight in solid content).

Various physical property tests were carried out using the obtained coating aqueous resin composition. 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 coating aqueous resin composition of the present invention is, for example, a coating aqueous resin composition such as a mastic coating, a soundproofing coating, a vibration damping coating, a caulking material, etc., among them, vehicles, particularly automobile chassis, gasoline. A tank, a coating aqueous resin composition having excellent chipping resistance used as a coating agent for protecting outdoor metalworking members such as suspensions,

Even when a thick coating film having a thickness of, for example, 600 μ or more is formed, blistering or cracking does not occur in the coating film in the drying process, and the formed film has a thickness of, for example, about 300 μ. The aqueous resin composition for coating has excellent chipping resistance even when the coating is relatively thin.

The aqueous resin composition for coating of the present invention comprises
(Co) polymer with a specific glass transition point, modified inorganic filler,
And characterized by comprising heat-expandable polymer beads and / or hollow polymer beads,

As a result, excellent physical properties that cannot be achieved by using a conventional aqueous copolymer emulsion, that is, chipping resistance at room temperature, and particularly when the film is wet; for example, -30 Impact resistance at extremely low temperatures such as ℃; excellent adhesion to metalworking members; flat and uniform film formation; water resistance; gasoline resistance; soundproofing and other properties as a chipping resistant coating Can be combined well.

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[Procedure amendment]

[Submission date] February 3, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0118

[Correction method] Change

[Correction content]

(1) Preparation of test piece After washing the surface of 0.8 × 100 × 200 mm tan sheet steel sheet manufactured by Nippon Steel Co., Ltd. with a thinner, each sample was dried and coated by an airless spray coating method. Is coated to a specified thickness, and hot air circulation dryer is used to
After preliminary drying at 15 ° C for 15 minutes, heat treatment is performed at 120 ° C for 20 minutes.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0150

[Correction method] Change

[Correction content]

[0150]

[Table 3]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C09D 5/00 PPU 6904-4J 5/08 PQH 6904-4J 109/00 PGP 8218-4J 133/08 PFX 7921-4J 201/00 PDC 7415-4J

Claims (1)

[Claims] 1. The following (A) to (C) and (A) glass transition points are 0 ° C.
The following (co) polymer, (B) modified inorganic filler, and
(C) A water-based resin composition for coating, comprising heat-expandable polymer beads and / or hollow polymer beads.