JPH06157975A - Water-base-resin coating composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition well balanced among chipping resistance, adhesiveness and water resistance, etc., and useful for the painting of a work material for exterior metal plate of vehicles by dispersing specific polymer fine particles, an inorganic filler and specific beads in aq. medium. CONSTITUTION:This resin coating composition is obtained by dispersing (A) polymer fine particles containing (i) 50-95wt.% of synthetic rubber emulsion polymer particles having a glass transition temperature of <=0 deg.C and containing 30-90wt.% of a conjugated diolefin unit, (ii) 5-50wt.% of emulsion polymer particles having a glass transition temperature of >=20 deg.C and containing 30-99.9wt.% of a repeating unit of the formula (R<1> is H or methyl; Q is COOR<2> (R<2> is lower alkyl), 6-12C aryl or CN) and (iii) 0-100 pts.wt. of urethane resin emulsion particles based on 100 pts.wt. of the total of components (i) and (ii), (B) an inorganic filler and (C) thermally expandable polymer beads and/or hollow beads in an aq. medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous resin coating composition, and more specifically, for example, an aqueous resin coating composition used as a mastic paint, a soundproof paint, a vibration-proof paint, a caulking material, etc. Especially used to protect the sheet metal working member from scratches, so-called "chipping", on the outdoor floor metal parts of automobiles, tire houses, chassis, gasoline tanks, suspensions, etc. due to flying stones, etc., chipping resistance, Adhesion to metal working members, uniformity and smoothness of coating film, water resistance, gasoline resistance,
Chipping resistance based on synthetic rubber emulsion polymer particles, which is excellent in various properties such as impact resistance and soundproofing, and also excellent in low temperature characteristics such as chipping resistance at extremely low temperatures of -30 ° C or lower. Water-based resin coating composition.

[0002]

2. Description of the Related Art Conventionally, an aqueous resin dispersion liquid such as a rubber latex or an acrylic copolymer emulsion is used as a vehicle as a water-based anti-chipping coating agent used for outdoor sheet metal working members of vehicles such as automobiles, Those containing an inorganic filler such as calcium carbonate or talc are known, and those based on an acrylic copolymer aqueous resin dispersion are disclosed in, for example, JP-A Nos. 53-64287 and 59-59. -75954, JP 62-230868, JP
It is disclosed in Japanese Patent Application Laid-Open No. 63-10678 and Japanese Patent Application Laid-Open No. 63-172777.

However, the aqueous coating agents for chipping resistance described in these publications are resistant to chipping at room temperature (hereinafter sometimes referred to as "normal chipping resistance"), and further to chipping resistance immediately after being wet with water ( Hereinafter, it may be referred to as "wet chipping resistance"), excellent adhesion to sheet metal processed members, impact resistance, especially for example-
Properties such as impact resistance at extremely low temperatures of 30 ° C or less (hereinafter sometimes referred to as “low temperature impact resistance”) as a chipping resistant coating agent, and when forming a thick coating film of 600μ or more, for example It is not easy to satisfy both anti-blister properties in the drying process, and in order to improve normal state chipping resistance and low temperature impact resistance, reducing the amount of inorganic filler in the coating agent causes blistering in the baking process. Easier to do,
Further, if the amount of the filler is increased to prevent blistering, there is a problem that the normal state chipping resistance and the low temperature impact resistance are significantly lowered.

In addition, in recent years, in the manufacture of automobiles and the like, in order to improve the anticorrosion property, for example, a method of assembling a body, a chassis and the like and then "catching" the whole body by cation electrodeposition is often adopted. When such a cationic electrodeposition coated sheet metal working member is coated with the chipping-resistant coating material described in the above publication, the adhesiveness of the coating material tends to be insufficient, and the wet chipping resistance is significantly reduced. There is a tendency.

On the other hand, an aqueous coating agent for chipping resistance using a rubber latex as a vehicle is disclosed in, for example, Japanese Patent Laid-Open No.
-180617, JP 59-75954, JP 59-1
It is disclosed in Japanese Patent No. 29213.

However, the aqueous coating agents for chipping using the latex described in these publications have a problem that it is difficult to say that they have sufficient normal state and wet chipping resistance and low temperature impact resistance.

Further, a water resistant coating agent for chipping using a rubber latex blended with another copolymer as a vehicle is also known. For example, JP-A-54-52139 discloses a vehicle. It has been proposed that a styrene-butadiene copolymer resin and a vinyl chloride-vinyl acetate-unsaturated dibasic acid copolymer resin and low-molecular liquid polymers are blended in specific amounts.

However, in the examples of the above-mentioned publications, a powder form is used as the vinyl chloride-vinyl acetate-unsaturated dibasic acid copolymer resin, but the copolymer resin powder is not dispersed. It was not easy, and it was found that the obtained coating film had insufficient adhesion to the sheet metal working member and insufficient chipping resistance.

Further, for example, in JP-A-2-28269, the glass transition temperature formed by emulsion polymerization of styrene, butadiene and an acrylic monomer is used as a base resin (vehicle component) in a water resistant coating for chipping. It has been proposed to use a copolymer having a butadiene content of 0 to 50 ° C. and a butadiene content of 5 to 50 parts by weight per 100 parts by weight of the copolymer.

However, according to the examples of the above-mentioned publication, the base resin is prepared by emulsion polymerization of an acrylic monomer in the presence of styrene-butadiene rubber latex. An attempt was made to prepare a copolymer according to the method described in Examples, and during emulsion polymerization of an acrylic monomer in the presence of styrene-butadiene rubber latex, the residual double bond derived from the butadiene unit in the rubber latex was Since the acrylic monomer is graft-polymerized, a copolymer having desired rubber elasticity cannot be obtained, and only a hard and brittle copolymer can be obtained.

Furthermore, the coating of the chipping-resistant coating agent on the parts other than the body such as the chassis, gasoline tank and suspension among the automobile parts is generally performed on a line different from the body painting line, but particularly recently. In order to reduce automobile manufacturing costs, it has been attempted to set the coating film baking temperature of the coating line to a relatively low temperature, such as 100 ° C. or lower, in which case the problem of blistering can be almost avoided. Although it is advantageous, it has also been found that there is a problem that the adhesion of the coating material to these parts is further reduced.

The present inventors have developed a chipping-resistant coating such as normal and wet chipping resistance, low temperature impact resistance, adhesion to substrate surface, coating film uniformity and smoothness, water resistance and solvent resistance. It has a good balance of various properties as an agent, and even when forming a thick coating film on a sheet metal processed member that is subjected to high temperature baking, such as an automobile body, it does not cause inconvenience such as blistering during the baking process. Intensive research was conducted for the purpose of providing a chipping aqueous resin coating composition.

A chipping-resistant water-based resin coating composition, which is mainly used for coating sheet metal working members such as parts other than the above-mentioned automobile body, and has a coating film baking temperature of, for example, a relatively low temperature of 100 ° C. or lower. And when
Provided is a chipping-resistant water-based resin coating composition which does not impair the adhesion of a coating film to a substrate surface, which tends to be deteriorated, and has a good balance of the above-mentioned various other properties as a chipping-resistant coating agent. Further research was carried out for that purpose.

As a result, as a vehicle component of the aqueous resin coating composition, a synthetic rubber emulsion polymer having a glass transition temperature (hereinafter sometimes referred to as Tg) of 0 ° C. or less,
It has been found that the above object can be achieved by using in combination with a specific emulsion polymer having a relatively high Tg of 20 ° C. or higher (hereinafter sometimes referred to as high Tg emulsion polymer). The present invention has been completed. When a urethane emulsion polymer is used in combination as the vehicle component in addition to the above two emulsion polymers, wet chipping resistance of the aqueous resin coating composition, sheet metal working member (base material), In particular, it has been found that the adhesion to a substrate such as a cationic electrodeposition coated steel sheet is further improved.

[0015]

However, the above aqueous resin coating composition is then coated by a rapid drying shrinkage during heating and drying depending on the blending amount of the fibrous or irregular inorganic filler such as light calcium carbonate or irregular calcium carbonate. It was found that there are problems such as cracks in the film, and as a result of further research, the aqueous resin coating composition was further expanded, for example, with heat-expandable polymer beads that expand by heating at about 110 ° C. Alternatively, by containing hollow beads, it is possible to obtain an excellent aqueous resin coating composition capable of preventing the occurrence of cracks in the coating film while maintaining the excellent properties of the aqueous resin coating composition. The present invention has been completed and the present invention has been completed.

[0016]

Thus, according to the present invention, there is provided an aqueous resin coating composition comprising polymer fine particles (A) and an inorganic filler (B) dispersed in an aqueous medium. , The polymer fine particles,

(A-1) 50 to 95% by weight of synthetic rubber emulsion polymer particles containing 30 to 90% by weight of conjugated diolein unit and having a glass transition temperature of 0 ° C. or lower,

(A-2) Formula (1),

[0019]

[Chemical 1]

(Wherein R ¹ is a hydrogen atom or a methyl group, and Q is
Is —COOR ² , an aryl group having 6 to 12 carbon atoms, or —C
N and R ² represent a lower alkyl group)

30 to 99.9% by weight of the repeating unit represented by
5 to 50% by weight of emulsion polymer particles having a glass transition temperature of at least 20 ° C., and

(A-3) The urethane resin emulsion particles are added to the emulsion polymer particles (A-1) and (A-2) in a total amount of 10
0 to 100 parts by weight with respect to 0 parts by weight, further,

An aqueous resin coating composition comprising (C) heat-expandable polymer beads and / or hollow beads is provided.

In the present specification, the expression "emulsion polymer particles" means fine particles of a polymer dispersed in an aqueous medium, the average particle diameter of which is usually 1 μm or less, preferably 0.05 to 0.5. In μ, it means dispersed particles,
It does not necessarily mean only polymer particles obtained by emulsion polymerization. In particular, the urethane-based resin emulsion particles (A-3) can be produced without emulsion polymerization as described later.

The aqueous coating composition of the present invention will be described in more detail below.

Synthetic Rubber Emulsion Polymer Particles (A-1) The synthetic rubber emulsion polymer particles (A-1), which is an essential component of the vehicle in the aqueous resin coating composition of the present invention, is
Conjugated dioleophin unit, based on the weight of the synthetic rubber polymer, 30 to 90% by weight, preferably 40 to 80% by weight,
More preferably, it is composed of a copolymer having rubber elasticity contained in a proportion of 45 to 75% by weight.

Such a synthetic rubber-based copolymer can be prepared by a method similar to the method for producing a synthetic rubber-based copolymer latex which is known per se, for example, (a-1) a conjugated diolefin-based monomer and (a- 2) an aromatic vinyl monomer and / or a vinyl cyanide monomer, preferably (a-3) a carboxyl group-containing ethylene-based monomer, and optionally (a-4) other It can be formed by carrying out aqueous emulsion polymerization under pressure together with the copolymerizable monomer of.

Examples of the conjugated diolefin-based monomer (a-1) include one or more monomers selected from butadiene, inprene and chloroprene.
Butadiene is particularly preferable. The aromatic vinyl monomer (a-2) includes, for example, styrene, α-methylstyrene, vinyltoluene, ethylvinylbenzene, etc., and the vinyl cyanide monomer (a-2), For example, acrylonitrile, methacrylonitrile, etc. can be illustrated. These aromatic vinyl monomers and / or vinyl cyanide monomers (a-2) can be used alone or in combination of two or more kinds. Particularly, styrene and / or acrylonitrile is preferable.

Further, in the carboxyl group-containing ethylene monomer (a-3) used in a suitable case, 1 or 2 carboxyl groups in one molecule, which may be in a free form or a salt or an anhydride form, are contained. And α, β-ethylenically unsaturated monomers having 1 to 3 carbon atoms are included, for example, α, β-unsaturated monocarboxylic acids having 3 to 5 carbon atoms such as acrylic acid, methacrylic acid and crotonic acid; citraconic acid, itaconic acid , Maleic acid,
C4 to C5 α, β-unsaturated dicarboxylic acids such as fumaric acid or their anhydrides or C1 to C12 monoalkyl esters (for example, monoethyl ester, mono-n-butyl ester, etc.); or Examples thereof include salts of these carboxylic acids (for example, ammonium salts, alkali metal salts, etc.). These monomers may be used alone or in 2
It is possible to use a combination of two or more species. Among these carboxyl group-containing ethylene-based monomers, acrylic acid, methacrylic acid, and itaconic acid can be particularly preferably used.

The synthetic rubber emulsion polymer particles used in the present invention include the conjugated diolefin monomer (a-1) and the aromatic vinyl monomer and / or vinyl cyanide monomer ( a-2) as an essential monomer component, more preferably can be produced by copolymerizing a carboxyl group-containing ethylene-based monomer in combination, the synthetic rubber-based copolymer latex If desired, other monomers may be further copolymerized, as is often the case during production.

Such other copolymerizable monomer (a-4)
For example, the following may be mentioned.

Esters of acrylic acid or methacrylic acid: for example, methyl acrylate, ethyl acrylate, n-butyl acrylate, i-butyl acrylate,
n-octyl acrylate, i-octyl acrylate, 2-
Ethylhexyl acrylate, i-nonyl acrylate,
An alkyl ester having 1 to 18 carbon atoms of acrylic acid or methacrylic acid such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate and n-dodecyl methacrylate.

Radical-polymerizable unsaturated monomer containing at least one crosslinkable functional group: for example, acrylamide, methacrylamide, diacetone acrylamide, N-
Amides of α, β-unsaturated carboxylic acids such as methylolacrylamide and N-methylolmethacrylamide, or derivatives thereof; for example, α, β-unsaturated carboxylic acids such as glycidyl acrylate and glycidyl methacrylate, and saturated alcohols having an epoxy group Esters of, for example, 2-
Hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-
Esters of α, β-unsaturated carboxylic acids such as hydroxypropyl methacrylate and polyvalent saturated alcohols;

For example, α, β-of dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc.
Esters of unsaturated carboxylic acids and saturated alcohols having amino groups; for example, divinylbenzene, diallyl phthalate, triallyl cyanurate, ethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanedioldi Monomers having two or more radical polymer unsaturated groups such as acrylate, diethylene glycol dimethacrylate, and allyl methacrylate;
etc.

The above-mentioned monomer components (a-1) to (a-4)
The use ratio of can be varied within a wide range depending on the physical properties required for the synthetic rubber emulsion polymer particles to be formed, but usually it can be used within the following range.

[0036]

[Table 1]

Synthetic rubber latex polymer particles (A-1)
Protects the above-described monomer components (a-1) to (a-4) in the presence of a surfactant and, if necessary, in the same manner as in the known synthetic rubber-based latex production method. In an aqueous medium in the presence of a colloid, about 30 to about 100 ℃, preferably about 40 ~
It can be produced by emulsion polymerization at a temperature of about 90 ° C. and usually under pressure.

As the surfactant, any type of nonionic, anionic, cationic or amphoteric surfactant can be used.

Examples of nonionic surfactants include polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether and the like. Oxyalkylene alkylphenol ethers; for example, sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monostearate and sorbitan trioleate;

For example, polyoxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate; for example, polyoxyalkylene fatty acid esters such as polyoxyethylene monolaurate, polyoxyethylene monostearate; for example, oleic acid Glycerin fatty acid esters such as monoglyceride and stearic acid monoglyceride; polyoxyethylene / polyoxypropylene / block copolymers; and the like,

Examples of the anionic surfactants include fatty acid salts such as sodium stearate, sodium oleate and sodium laurate; alkylarylsulfone hydrochlorides such as sodium dodecylbenzenesulfonate; sodium lauryl sulfate and the like. Alkyl sulphonic acid ester salts of: Alkyl sulfosuccinic acid ester salts such as sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium polyoxyethylene lauryl sulfosuccinate and derivatives thereof; for example, polyoxyethylene lauryl ether sulphate Oxyalkylene alkyl ether sulfate ester salt; for example, polyoxyalkylene alkyl such as polyoxyethylene nonylphenol ether sodium sulfate Reel ether sulfate ester salts: like can be exemplified,

As the cationic surfactant, for example, an alkylamine salt such as laurylamine acetate;
For example, lauryl trimethyl ammonium chloride,
Examples thereof include quaternary ammonium salts such as alkylbenzyldimethylammonium chloride; polyoxyethylalkylamine; and the like, and amphoteric surfactants include, for example, alkylbetaine such as laurylbetaine.

Further, some of the hydrogen atoms of the alkyl groups of these surfactants are replaced by fluorine; so-called reactive surfactants having a radical copolymerizable unsaturated bond in the molecular structure of these surfactants. , Etc. can also be used.

Of these surfactants, polyoxyalkylene alkyl ethers and polyoxyalkylene alkyl phenol ethers are used as the nonionic surfactants from the viewpoint of generation of agglomerates during emulsion polymerization and the like. As the anionic surfactant, 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, etc. are used. Preferably. These surfactants can be used alone or in an appropriate combination.

The amount of these surfactants used may vary depending on the type of surfactant used, etc., but generally 100 parts by weight in total of the monomer components (a-1) to (a-4). About 0.5
It may be in the range of about 10 parts by weight, but the polymerization stability of the aqueous emulsion polymerization, the storage stability of the resulting synthetic rubber-based polymer emulsion and the chipping resistance when used in the aqueous resin coating composition, From the viewpoint of excellent adhesion to a base material such as a sheet metal working member, about 1 to 6 parts by weight, particularly about 1 to
It is preferably used within the range of 4 parts by weight.

Examples of the protective colloid which can be used in the production of the synthetic rubber polymer emulsion include polyvinyl alcohols such as partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol and modified polyvinyl alcohol; for example, hydroxy. Cellulose derivatives such as ethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose salt and the like; for example, natural polysaccharides such as guar gum and the like can be mentioned.

The amount of these protective colloids used is also not strictly limited and can be changed according to the kind of the colloid. Usually, the above-mentioned monomer components (a-1) to (a-4) are used. An amount of about 0 to 3 parts by weight can be exemplified with respect to 100 parts by weight in total.

The emulsion polymerization of the monomer components (a-1) to (a-4) is carried out using a polymerization initiator. Polymerization initiators that can be used include, for example, persulfates such as ammonium persulfate, sodium persulfate and potassium persulfate;
Organic peroxides such as t-butyl hydroperoxide, cumene hydroperoxide and p-menthane hydroperoxide; hydrogen peroxide: and the like, and these may be used alone or in combination of two or more. it can.

The amount of the above-mentioned polymerization initiator to be used is not strictly limited and can be varied within a wide range depending on the type and reaction conditions, but in general, the above-mentioned monomer components are used.
About 0.05 to about 100 parts by weight of the total of (a-1) to (a-4).
The amount used is, for example, about 1 part by weight, more preferably about 0.1 to about 0.7 part by weight, particularly preferably about 0.1 to about 0.5 part by weight.

In emulsion polymerization, a reducing agent may be used in combination, if desired. Examples of the reducing agent that can be used 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. It can be illustrated. The amount of these reducing agents used is also not particularly limited, but is generally about 0.05 to about 1 part by weight based on 100 parts by weight of the total of the monomers (a-1) to (a-4). The range can be exemplified.

Furthermore, a chain transfer agent can be optionally used in the emulsion polymerization. Examples of such chain transfer agents include cyanoacetic acid; cyanoacetic acid alkyl esters having 1 to 8 carbon atoms; bromoacetic acid; bromoacetic acid alkyl esters having 1 to 8 carbon atoms; anthracene, phenanthrene, fluorene, 9 -Polycyclic aromatic compounds such as phenylfluorene; p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid,
Aromatic nitro compounds such as p-nitrophenol, p-nitrotoluene; benzoquinone, 2,3,5,6-tetramethyl-p-
Benzoquinone derivatives such as benzoquinone; Borane derivatives such as tributylborane;

Halogenated carbonization of carbon tetrabromide, carbon tetrachloride, 1,1,2,2-tetrabromoethane, tribromoethylene, trichloroethylene, bromotrichloromethane, tribromomethane, 3-chloro-1-propene, etc. Hydrogen; aldehydes such as chloral and furaldehyde; for example, n-dodecyl mercaptan such as alkyl mercaptans having 1 to 18 carbon atoms; thiophenenol, toluene mercaptans and other aromatic mercaptans; mercaptoacetic acid; Examples thereof include alkyl esters of 10; hydroxyalkyl mercaptans having 1 to 12 carbon atoms such as 2-mercaptoethanol; terpenes such as binene and terpinolene.

When the chain transfer agent is used, the amount thereof used is in the range of about 0.005 to about 3 parts by weight based on 100 parts by weight of the monomers (a-1) to (a-4). Is preferred.

The synthetic rubber polymer emulsion (latex) formed by emulsion polymerization as described above is generally in the range of 10 to 70% by weight, preferably 30 to 60% by weight, more preferably 40 to 60% by weight. It has a solid content of 10 cps or less, especially when measured with a B-type rotational viscometer at 25 ° C. and 20 rpm.
It is desirable to be in the range of about 5,000 cps.

The above emulsions are usually 2-10, especially 5-
It is desirable to have a pH within the range of 9, and the pH can be adjusted by using, for example, aqueous ammonia, aqueous amine solution, or aqueous alkali hydroxide solution.

The synthetic rubber emulsion polymer particles (A-1) used in the aqueous resin coating composition of the present invention have a Tg of
Is 0 ° C. or lower, preferably −10 ° C. or lower, and more preferably −20 to −80 ° C. Tg
A coating formed from an aqueous resin coating composition prepared using synthetic rubber-based emulsion polymer particles having a temperature of higher than 0 ° C. generally has low chipping resistance and is not very preferable.

In the present specification, the glass transition temperature (Tg) of polymer particles is a value measured by the following method.

Glass transition point (Tg): About 10 mg of a sample of (co) polymer emulsion was weighed into 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. The sample dried at 100 ° C for 2 hours was used as a measurement sample, and a differential scanning calorimeter [Differential Scanning Calorimeter: "SSC-5000" type manufactured by Seiko Instruments Inc.] was used.
The specific heat capacity difference before and after the glass transition temperature of the sample is measured at a temperature rising rate of 10 ° C./min, and Tg is determined from the result.

Further, it is desirable that the synthetic rubber emulsion polymer particles generally have a gel fraction within the range of 60 to 98% by weight, particularly 70 to 95% by weight.

In this specification, the gel fraction of the synthetic rubber emulsion polymer particles (A-1) is the value measured by the following method.

Gel fraction: A film was prepared from a synthetic rubber polymer emulsion 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 film from the polymer emulsion, and the value obtained by subtracting the toluene-soluble content (% by weight) from 100% by weight, that is, The toluene insoluble content (% by weight) is defined as the gel fraction.

Further, the average particle size (hereinafter sometimes referred to simply as the particle size) of the synthetic rubber polymer particles (A-1) dispersed in the emulsion produced as described above is
Generally, it is desirable that the thickness is in the range of 0.05 to 0.5μ, particularly 0.1 to 0.3μ. The particle diameter of the polymer particles in the emulsion can be controlled by, for example, appropriately selecting the document and amount of the surfactant used, and further the polymerization temperature.

In the present specification, the average particle size of the polymer particles is the average particle diameter of the polymer particles, "New Experimental Chemistry Course 4 Basic Technology 3 Light (II)", edited by the Chemical Society of Japan, pp. 725-741 (July 20, 1976). It is measured by the DLS method described in Maruzen Co., Ltd., and specifically, the value determined by the method described below.

Average particle size: The (co) polymer emulsion was diluted 50,000 to 150,000 times with distilled water, and after sufficiently stirring and mixing,
About 10 using a Pasteur pipette in a 21 mmφ glass cell
ml is sampled, set in a predetermined position of a dynamic light scattering photometer "DLS-700" (manufactured by Otsuka Electronics Co., Ltd.), and measured under the following measurement conditions.

[Measurement conditions]

[Table 2] The average particle size is calculated by computer processing the measurement results.

Synthetic rubber emulsion polymer particles (A-1)
As other than those manufactured by the above-mentioned method, for example,
"LX-407C" (manufactured by Nippon Zeon Co., Ltd.), "SN-318", "SN-
534 ”,“ SN-562 ”,“ J-1666 ”[above, Sumitomo Dow Co., Ltd.
Made], “SK-80” [made by Takeda Pharmaceutical Co., Ltd.], “L-200
1 "," L-2337 "[above, manufactured by Asahi Kasei Kogyo Co., Ltd.]," Polylac 707 "[manufactured by Mitsui Toatsu Chemical Co., Ltd.], etc. Hereinafter, it may be abbreviated as SBR); "Nipol 157
1 "," Nipol 1551 "," Nipol 1562 "[above,
Acrylonitrile-butadiene-based synthetic rubber latex (hereinafter, referred to as N
(Sometimes abbreviated as BR) etc. can also be used.

High Tg emulsion polymer particles (A-2) In the aqueous resin coating composition of the present invention, the synthetic rubber emulsion polymer particles (A-1) described above are used as a vehicle component.
The high Tg emulsion polymer particles (A-2) that can be used in combination with

[0068]

[Chemical 3]

(In the formula, R ¹ is a hydrogen atom or a methyl group, and Q is
Is —COOR ² , an aryl group having 6 to 12 carbon atoms, or —C
N and R ² each represent a lower alkyl group), and the repeating unit is represented by 30 to 99.9% by weight based on the weight of the polymer.
Preferably 35 to 98.5% by weight, more preferably 40 to 96
It is composed of a (co) polymer which can be contained in a proportion of% by weight, and can further contain one kind or two or more kinds of other monomer units, if necessary.

Suitable as such another monomer unit is a repeating unit derived from a carboxyl group-containing ethylene-based monomer described later, and the (co) polymer preferably has such a unit of 0.1 or less. ~ 10% by weight, more preferably
The content may be 0.5 to 5% by weight. Further, the (co) copolymer may contain a repeating unit derived from a hydroxyl group-containing ethylene-based monomer described later, preferably in an amount of 1 to 20% by weight, particularly 3 to 15% by weight.

Such (co) polymers can be obtained, for example, by the formula (b-1)
(2)

[0072]

[Chemical 4]

(Wherein R ¹ and Q are as defined above)

An ethylene-based monomer represented by the following formula, wherein the homopolymer of the monomer is hydrophobic and its Tg is 40 ° C.
Monomer and the above, (b-2) carboxyl group-containing ethylene-based monomer, preferably, (b-3) hydroxyl group-containing ethylene-based monomer, and, if necessary, further (b- 4) It can be produced by emulsion polymerization with another copolymerizable monomer.

The above-mentioned monomer (b-1) is, for example, an alkyl ester of methacrylic acid having 1 to 4 carbon atoms such as methylmethacrylate, ethylmethacrylate, i-butylmethacrylate; styrene, α-methylstyrene. Aromatic vinyl compounds such as vinyltoluene and ethylvinylbenzene; (meth) acrylonitrile; Of these, methyl methacrylate, styrene, and acrylonitrile are preferable as the monomer (b-1) from the viewpoints of easy availability, emulsion polymerization, and the like.
Each of these monomers can be used alone or 2
You may use together 1 or more types.

Carboxyl group-containing ethylene monomer (b-
As 2), the same one as the carboxyl group-containing ethylene-based monomer (a-3) described above in the production of the synthetic rubber-based polymer can be used. Suitable as the monomer (b-2) are acrylic acid, methacrylic acid and itaconic acid, as in the monomer (a-3).

Further, a hydroxyl group-containing ethylene monomer (b-3)
Includes an α, β-ethylenically unsaturated monomer containing 1 to 4, preferably only 1 hydroxyl group in one molecule, and examples thereof include 2-hydroxyethyl (meth) acrylate and 2-hydroxyl. Examples thereof include hydroxyalkyl esters of (meth) acrylic acid having 2 to 2 carbon atoms such as propyl (meth) acrylate.

Further, the other copolymerizable monomer (b-4) that can be used if necessary is, for example, "other copolymerizable monomer (a -4) ”as well as the above-mentioned monomers and, for example, saturated fatty acid vinyl monomers having 1 to 12 carbon atoms such as vinyl formate, vinyl acetate, vinyl propionate, and“ vinyl versatate ”(trade name); For example, monoolefin monomers such as ethylene, propylene, n-butylene, and i-butylene; conjugated diolefin monomers such as butadiene, isoprene, and chloroprene;

For example, dibutyl malate, dioctyl malate, dibutyl fumarate, dioctyl fumarate,
1 to 12 carbon atoms of unsaturated α, β-dicarboxylic acid having 4 to 5 carbon atoms such as dibutyl itaconate and dioctyl itaconate
And the like. The above-mentioned monomers can be used alone or in combination of two or more kinds. These monomers are
It can be appropriately selected depending on the physical properties desired for the polymer to be formed, for example, Tg. Among them, vinyl acetate,
“Versic acid vinylate” (trade name) and butadiene are preferable.

The above-mentioned monomers (b-1) to (b-4) are prepared by the same emulsion polymerization method as described above for the production method of the synthetic rubber latex polymer particles (A-1) [usually Emulsion polymerization under atmospheric pressure].

In the aqueous resin coating composition of the present invention, high Tg emulsion polymer particles (A-2) which can be used as a vehicle component in combination with the above-mentioned synthetic rubber emulsion polymer particles (A-1). ), Tg is at least
Examples include those at 20 ° C. The glass transition temperature (Tg) required for the polymer particles (A-2) is preferably adjusted according to the baking temperature of the coating film formed from the final coating composition. For example, the baking temperature is In the case of a coating composition for low temperature baking at about 60 to 100 ° C, polymer particles (A-2) used
Conveniently, the Tg is in the range of 20 ° C to less than 60 ° C, preferably 30 ° C to 55 ° C, while the baking temperature is about 12 ° C.
In the case of a coating composition for high temperature baking at 0 to 160 ° C., the Tg of the polymer particles (A-2) incorporated therein is generally 60 ° C. or higher, particularly 70 ° C. or higher, more preferably 85 ° C. or higher. .

Therefore, the monomers (b-1) to (b-4) for producing the high Tg polymer particles (A-2) have different types of monomers so as to satisfy the above Tg. Also, emulsion polymerization can be performed by selecting the use ratio. The following range can be illustrated as a general range of the usage ratio of these monomers.

Monomer (b-1): 30 to 99.9% by weight Monomer (b-2): 0.1 to 10% by weight Monomer (b-3): 0 to 30% by weight Monomer (b -4): 0 to 70% by weight Note:% by weight is a percentage based on the total amount of monomers.

The suitable use ratio of each monomer component depends on the use (for low temperature baking or high temperature baking) of the aqueous resin coating composition with which the high Tg polymer particles (A-2) to be formed are blended. You can then choose from the following ranges:

(1) Used in aqueous resin coating composition for low temperature baking
In case of high Tg polymer particles (A-2):

[0086]

[Table 3]

(2) Used in aqueous resin coating composition for high temperature baking
In case of high Tg polymer particles (A-2):

[0088]

[Table 4]

The (co) copolymer emulsion formed by emulsion polymerization of these monomers (b-1) to (b-4) generally comprises high Tg polymer particles (A-2) as a solid content. 10-70% by weight, preferably 30-65% by weight, more preferably 40-
It can be contained within the range of 60% by weight, and the viscosity when measured with a B-type rotational viscometer at 25 ° C and 20 rpm is usually 10,000 cps or less, and particularly within the range of about 10 to 5,000 cps. It is convenient to have.

The above emulsions are usually 2-10, especially 5-
It is desirable to have a pH within the range of 9, and the pH can be adjusted by using, for example, aqueous ammonia, aqueous amine solution, or aqueous alkali hydroxide solution.

It is desirable that the high Tg emulsion polymer particles (A-2) generally have a weight average molecular weight of 500,000 or more, particularly 800,000 or more. The average particle size of the high Tg polymer particles (A-2) dispersed in the polymer emulsion to be formed is generally 0.05 to 0.5 μ, and particularly preferably 0.1 to 0.3 μ, The particle size of the high Tg polymer particles (A-2) can be controlled in the same manner as the particle size of the synthetic rubber emulsion polymer particles (A-1).

Urethane resin emulsion particles (A-3):
As the urethane resin emulsion particles (A-3) that can be appropriately blended with the aqueous resin coating composition of the present invention, a urethane resin emulsion known per se in the fields of paints, adhesives, etc. can be used. .

Such a urethane resin emulsion is prepared by reacting a urethane prepolymer having an isocyanate group at the terminal, which is obtained from a polyisocyanate compound and a polyol compound, with a chain extender and emulsifying in accordance with a usual method. be able to.

Examples of the polyisocyanate compound that can be used in the production of the urethane resin emulsion (A-3) include 1,3- or 1,4-phenylene diisocyanate and 2,4- or 2,6-tolylene diisocyanate. , 1,5-
Naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethyldiphenylmethane-4,
Aromatic polyisocyanate compounds such as 4'-diisocyanate and 1,3-xylylene diisocyanate;

For example, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, 1,8-
Aliphatic polyisocyanate compounds such as octamethylene diisocyanate and 1,10-decamethylene diisocyanate; eg 1,3- or 1,4-cyclohexylene diisocyanate, 1-methylcyclohexane-1,3- or 1,4-
Examples thereof include diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and aliphatic polyisocyanate compounds such as 1,3-isocyanomethylcyclohexane.

Among these polyisocyanate compounds, preferred are, for example, 2,4- or 2,6-tolylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate and isophorone diisocyanate. To be

Examples of the polyol compound which can be reacted with the polyisocyanate compound include polyester polyols, polyether polyols and polyester ether polyols.

Examples of the polyester polyols include ethylene glycol, propylene glycol, 1,4-
Butanediol, 1,6-hexanediol, glycerol, trimethylolpropane, pentaerythritol,
Polyhydric alcohols such as sorbitan and sorbitol, for example, succinic acid, adipic acid, sebacic acid, maleic acid,
Fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaric acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic acid, condensation products with polycarboxylic acids such as dodecanedicarboxylic acid, and lactone polymers Can be illustrated as

Examples of the polyether polyols include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol and polyethylene propylene glycol. The polyester ether polyols include the above polyester polyols. Examples thereof include those obtained by adding alkylene oxide such as ethylene oxide, and those having a hydroxyl group at the terminal obtained by condensing the above polyether polyols and the above polycarboxylic acid.

As the chain extender, a compound having at least two functional groups containing an active hydrogen atom reactive with an isocyanate group can be used. Typical examples thereof are water and polyhydric alcohol. And primary and secondary polyvalent amines, hydrazine and its derivatives, and the like.

Examples of the polyhydric alcohols include, for example,
Ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2- or 1,3-propylene glycol, 1,2-, 1,3- or 1,4-
Butylene glycol, 2,2-dimethyl-1,3-propylene glycol, 1,6-hexanediol, 2,2,4-trimethyl-
Aliphatic diols such as 1,3-pentanediol; eg 2,
Alicyclic diols such as 2,4,4-tetramethylcyclobutanediol, 1,3-cyclopentanediol and methylenebis (4-cyclohexanol); for example, 1,4-phenylenebis
(2-hydroxyethyl ether), aromatic diol such as 1,2-propylene glycol bis (2-hydroxyphenyl ether); and the like.

Examples of polyvalent amines include ethylenediamine, hexamethylenediamine, isophoronediamine, diaminodiphenylmethane, diethylenetriamine, and the like, and examples of hydrazine derivatives include dimethylhydrazine and 1,6- Substituted hydrazine such as hexamethylenebishydrazine; a reaction product of dicarboxylic acid, disulfonic acid, lactone or polyhydric alcohol and hydrazine; and the like.

Examples of the chain extender include, in addition to these, particularly those used for imparting ionicity to urethane prepolymers and urethane resins when they are emulsified. Specific examples thereof include For example,
Dihydroxycarboxylic acids such as 2,2-dimethylolacetic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, and 2,2-dimethylolvaleric acid; 2,5-diaminobenzoic acid,
and diaminocarboxylic acids such as α, β-caproic acid (lysine) and 2-amino-5-guanidinovaleric acid (arginine); alkyldialkanolamines such as methyldiethanolamine: and the like.

The above-mentioned urethane prepolymer having an isocyanate group at the end is prepared, for example, by using the polyisocyanate compound and the polyol compound in a ratio such that the isocyanate group becomes equivalent to the hydroxyl group in excess of the hydroxyl group. It can be produced by reacting in an organic solvent with stirring at a temperature of about 25 to 110 ° C., optionally in the presence of a catalyst.

Examples of the organic solvent which can be used here include ketones such as acetone and methyl ethyl ketone; ethers such as dioxane and tetrahydrofuran;
Examples thereof include esters such as ethyl acetate; aliphatic hydrocarbons such as heptane and octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane. In addition, useful reaction catalysts include, for example, tertiary amines such as triethylamine; inorganic salts such as stannous chloride; di-n-
Organometallic compounds such as butyltin dilaurate; and the like.

The urethane resin emulsion prepared from the urethane prepolymer prepared as described above and the chain extender can be produced by various methods known per se in the art.

As a method for producing a cationic emulsion, for example, (1) a urethane prepolymer having an isocyanate group at the terminal is polymerized using a diol having a tertiary amino group as a chain extender, and then a quaternizing agent is used. Alternatively, a method of cationizing with an acid, or reacting with a diol having a quaternary amino group as a chain extender to cationize,

(2) A method in which a urethane prepolymer having an isocyanate group at the terminal is polymerized by using polyalkylene polyamine as a chain extender and then cationized by reacting shrimp halohydrin with an acid can be mentioned. .

Further, as a method for producing an anionic emulsion, for example, (3) a urethane prepolymer having an isocyanate group at the terminal is polymerized with dihydroxycarboxylic acid or diaminocarboxylic acid as a chain extender and then alkalinized. A method of neutralizing with a compound to anion,

(4) A method in which a urethane prepolymer having an isocyanate group at the end, which is obtained from a hydrophobic polyol and an aromatic polyisocyanate, is sulfonated and neutralized with a tertiary amine to give an anion, and the like can be mentioned. .

Further, as a method for producing a nonionic emulsion, for example, (5) a urethane prepolymer having an isocyanate group at the terminal is dispersed in an aqueous solution containing a diamine and the like using an emulsifier, and water or Method of chain extension with diamine,

(6) A method of reacting a urethane prepolymer having an isocyanate group at the terminal with an alkylene oxide condensate of a long-chain alcohol (a type of nonionic surfactant) and an amine having a hydrophilic group such as a hydroxyl group,

(7) A method in which a urethane prepolymer having an isocyanate group at the terminal is reacted with the above chain extender to give a urethane resin and mechanically dispersed in water using an emulsifier, and the like can be mentioned.

As the urethane resin emulsion which can be used in the present invention, in addition to those described above, a hydroxyl group-containing vinyl monomer such as 2-hydroxyethyl acrylate is introduced into the urethane prepolymer,
Emulsion copolymerization of the urethane prepolymer and the (meth) acrylic monomer; 1 of the isocyanate groups of the urethane prepolymer having an isocyanate group at the terminal
Parts by blocking with various blocking agents or by reacting the urethane prepolymer or urethane-based polymer with a urethane prepolymer in which one part of the isocyanate group is blocked, and containing a blocked isocyanate in the molecule. It is also possible to use a urethane prepolymer or a urethane polymer, which is emulsified by the same method as described above;

Among these, as the urethane resin emulsion, the mixing stability with the synthetic rubber emulsion polymer particles (A-1) and the high Tg emulsion polymer particles (A-2) described above, the coating composition From the viewpoints of easiness of preparation of, the storage stability of the final coating composition, and the like, it is preferable to use an anionic or nonionic emulsion.

The average particle size of the polymer particles in the urethane resin emulsion produced as described above is generally in the range of 0.05 to 0.5 µ, preferably 0.1 to 0.3 µ.

Further, urethane resin emulsion particles
(A-3) is the degree of improvement of blistering prevention property during baking of the coating film formed using the final coating composition, wet chipping resistance, etc., the polymer particles (A- 100% of film formed from urethane resin emulsion containing 3)
The stress of elongation (hereinafter sometimes referred to as 100% modulus) or the yield value before 100% elongation, whichever is larger, is generally 20 kg / cm ² or more, preferably 30 kg / cm ² or more, and more preferably 40 kg / cm ² or more. It is desirable to be in the range of up to 300 kg / cm ² .

In this specification, the 100% modulus and the yield value of the film formed from the urethane resin emulsion are the values measured by the following method.

100% modulus and yield value of film
Measurement method: A release blade fixed horizontally is coated with a urethane resin emulsion with a doctor blade to a dry thickness of 50-100μ and dried at room temperature, then with a hot air circulation dryer at 120 ° C, 10 ° C. A urethane resin film is prepared by heat treatment for a minute. The obtained film is 23 ℃, 65% RH
After left under constant temperature and humidity conditions for 3 hours or more, the stress-elongation curve is measured under the same conditions, and the required numerical value is read from the curve.

For the measurement, "Tensilon UTM-4-100" (manufactured by Toyo Baldwin Co., Ltd.) was used with a sample width of 10 mm, a gripping interval of 10 mm and a pulling speed of 100 mm / min.

Aqueous resin coating composition: The aqueous resin coating composition of the present invention comprises synthetic rubber emulsion polymer particles (A-1) and high Tg emulsion polymer particles (A-2) which are essential components as vehicle components. ), Or a combination of these polymer particles (A-1) and (A-2), and urethane resin emulsion particles (A-3) that are used if necessary, and On the other hand, it can be prepared by blending the inorganic filler (B) and the heat-expandable polymer beads and / or hollow beads (C).

The blending amount of the polymer emulsions (A-1) and (A-2) is the total amount of the polymer particles (A-1) and (A-2) (that is, solid content) in these emulsions. Based on the standard, the synthetic rubber emulsion polymer particles (A-1) are 50 to 95% by weight, preferably 55 to 90% by weight, more preferably 60 to 90% by weight.
It may be in the range of 85% by weight, and the high Tg emulsion polymer particles (A-2) may be in the range of 5 to 50% by weight, preferably 10 to 45% by weight, more preferably 15 to 40% by weight. .

The above water-based resin coating composition may, if necessary, contain the urethane resin emulsion (A-3) described above.
The coating composition formed from the coating composition can be wet-chipping resistant, and the adhesion to a substrate, especially a cationic electrodeposition coated steel sheet can be markedly improved. The amount is a solid content, that is, a total of 100 parts by weight of the synthetic rubber emulsion polymer particles (A-1) and the high Tg emulsion polymer particles (A-2) as urethane resin emulsion particles (A-3). The amount can be within the range of 3 to 100 parts by weight, and in the case of the aqueous resin coating composition for low temperature baking, it is preferably within the range of 20 to 90 parts by weight, particularly 30 to 80 parts by weight, On the other hand, in the case of a high temperature baking aqueous resin coating composition, it is preferably in the range of 4 to 70 parts by weight, particularly 5 to 50 parts by weight.

The aqueous medium used in the aqueous resin coating composition of the present invention is derived from the above-mentioned emulsion and is usually water, but in some cases, a mixture of water and a water-miscible organic solvent is used. It may be a solvent.

The aqueous resin coating composition of the present invention comprises polymer fine particles (A) comprising the above synthetic rubber emulsion polymer particles (A-1) and high Tg emulsion polymer particles (A-2), or , These polymer particles (A-1) and (A-2), together with polymer fine particles (A) consisting of urethane resin emulsion particles (A-3) used as necessary, an inorganic filler (B) It contains.

The above-mentioned inorganic filler (B) is added to the composition for the purpose of increasing the amount of the filler, adjusting the hardness of the coating film, preventing the formation of blisters, etc. , Substantially water-insoluble or sparingly soluble inorganic solid powder, for example, calcium carbonate, silica, alumina, kaolin, clay, talc, diatomaceous earth, mica, aluminum hydroxide, glass powder, barium sulfate, magnesium carbonate, etc. be able to.

The blending amount of these inorganic fillers (B) can be varied within a wide range depending on the kind and the physical properties desired for the coating composition, but it is contained in the composition. The total amount of the polymer fine particles (A) is 100 to 390 parts by weight, preferably 120 to 380 parts by weight, and more preferably 150 to 300 parts by weight.

The above-mentioned inorganic filler (B) is generally about
It is desirable to have an average particle size in the range of 0.5 to about 50μ, especially 1 to about 30μ.

The aqueous resin coating composition of the present invention comprises the polymer fine particles (A) and the inorganic filler (B), and further contains heat-expandable polymer beads and / or hollow beads (C). .

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

Examples of the heating 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.

Examples of the heat decomposition type foaming agent include, 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 to 180 ° C.
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 size before thermal expansion of 1 to 50 μ, particularly about 3 to 40 μ, and an average particle size after thermal expansion of 5 to 300 μm.
It is preferably μ, particularly about 20 to 200 μ.

Examples of the heat-expandable polymer beads that can be suitably used in the present invention include “Matsumoto Microsphere F-30” and “Matsumoto Microsphere F-50” [above, Matsumoto Yushi-Seiyaku Co., Ltd.] Co., Ltd.],
"Expansell WU # 642", "Expansell WU ^# 55
1 "," Expansell WU ^# 461 "," Expansell D
Examples thereof include those commercially available under trade names such as "U ^# 551", "Expansell DU ^# 461", "Expansell DU ^# 051" [above, manufactured by Nippon Philite Co., Ltd.].

Some of these heat-expandable polymer beads are commercially available as a so-called "wet cake" containing water for the reason of easy handling, and the above-mentioned "Matsumoto Microsphere F". -30 "," Matsumoto Microsphere F-50 "," Expansell WU ^# 6 "
42 "," Expansell WU ^# 551 "," Expansell W
U ^# 461 ”etc. are this type.

Examples of the hollow beads that can be used in the present invention include hollow polymer beads and hollow inorganic beads.

The hollow polymer beads are similar to those used in the heat-expandable polymer beads, for example, polyolefin, polyacrylonitrile, polyacrylate,
Polystyrene, polyvinyl chloride, polyvinylidene chloride and copolymers thereof; polyester resins; silicone resins; thermoplastic urethane resins; and the like having a shell wall of a thermoplastic resin can be used. Those in which the beads have been thermally expanded in advance under appropriate heating conditions can be preferably used. In addition to these,
It is also possible to use a resin that uses a thermosetting resin such as an amino resin, a phenol resin, or an unsaturated polyester resin as the shell wall.

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

The hollow polymer beads which can be preferably used in the present invention include, for example, “Expansel D
Examples thereof include those marketed under the trade names such as "E ^# 551" and "Expansell WE ^# 551" [above, manufactured by Nippon Philite Co., Ltd.]. These hollow polymer beads, as in the case of the heat-expandable polymer beads, may be commercially available as so-called "wet cake" containing water for reasons such as ease of handling. "Expansell WE ^# 551" is this type.

As the hollow inorganic beads which can be used in the present invention, those having a shell wall made of an inorganic material such as glass, silica, shirasu, carbon, alumina and zirconia are preferably used.

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

Examples of the hollow inorganic beads that can be preferably used in the present invention include “Q-CEL 200” and “QC.
"EL 300", "Q-CEL 600" [above, Asahi Glass Co., Ltd.],
"Scotchlight B28 / 750", "Scotchlight B38 / 4
000 ”,“ Scotchlight B46 / 4000 ”[above, manufactured by Sumitomo 3M Ltd.] and the like are commercially available.

These heat-expandable polymer beads and hollow beads can be used in combination as appropriate.

The amount of the heat-expandable polymer beads and / or hollow beads (C) used in the present invention is generally 0.1 to 40 parts by weight, preferably 100 parts by weight based on 100 parts by weight of the polymer fine particles (A). 0.3-35 parts by weight, particularly preferably 0.5-
30 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 water-based resin coating composition of the present invention, if necessary, may be used in the same manner as in a usual coating composition, in the same manner as the rust preventive pigment,
Color pigments, crosslinking agents and the like can be contained.

Examples of the above-mentioned rust preventive pigment include red lead; for example, zinc chromate, barium chromate, strontium chromate, and other chromate metal salts; for example, zinc phosphate, calcium phosphate, aluminum phosphate, titanium phosphate, phosphorus. Silicon acid, or metal phosphates such as ortho or condensed phosphates of these metals; for example, zinc molybdate,
Metal molybdate salts such as calcium molybdate, zinc calcium molybdate, zinc potassium molybdate, potassium potassium phosphomolybdate, and potassium potassium molybdate phosphate; for example, calcium borate, zinc borate, barium borate, barium metaborate, calcium metaborate. Boric acid metal salt such as: and the like. Among these rust preventive pigments, nontoxic or low toxic rust preventive pigments such as metal phosphate, metal molybdate, and borate are preferred.

The amount of the rust preventive pigment compounded is, for example, 0 to 50 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of the polymer fine particles in the coating composition. it can.

Examples of the color pigments include organic or inorganic color pigments such as titanium oxide, carbon black, rouge, Hansa yellow, benzidine yellow, phthalocyanine blue and quinacridone red. The blending amount of these color pigments can be exemplified within the range of, for example, 0 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the polymer fine particles in the coating composition.

The particle size of these rust preventive pigments and color pigments is preferably in the range of 1 to 50 μ from the viewpoint of the smoothness of the coating film formed of the obtained coating composition.

The aqueous resin coating composition of the present invention may further contain, if necessary, a water-soluble polyvalent metal salt; an aziridine compound; a water-soluble epoxy resin; a water-soluble melamine resin; a water-dispersible blocked isocyanate. Can be included.

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 and barium nitrite; 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 salt such as lead;

For example, nickel salts such as nickel acetate, nickel chloride, nickel nitrate and nickel sulfate; for example, manganese salts such as manganese acetate, manganese chloride, manganese sulfate and manganese nitrate; for example, copper chloride, copper nitrate, copper sulfate and the like. Copper salt;

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

Examples of the polyisocyanate compound include m- or p-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, m- or p-xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and the like. Aromatic diisocyanate compound;

Aliphatic or alicyclic diisocyanate compounds such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated products of the above aromatic diisocyanate compounds, and dimer acid diisocyanates;

Examples thereof include dimers or trimers of these isocyanates; adducts of these isocyanates with divalent or trivalent polyols such as ethylene glycol and trimethylolpropane.

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

As the water-soluble melamine resin, for example, methylol melamine; at least a part of the hydroxyl group of the methylol melamine is methyl alcohol, ethyl alcohol,
Examples thereof include those etherified with n-butyl alcohol and the like.

Examples of the water-dispersible blocked isocyanate include trimethylolpropane tritolylene diisocyanate methyl ethyl ketoxime adduct and the like in which the above-mentioned polyisocyanate compound is impregnated with a volatile low molecular weight active hydrogen compound.

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 diacylaminoethanol; ketoxime compounds such as acetoxime and methylethylketoxime; active methylene compounds such as acetylacetone, acetoacetic acid ester and malonic acid ester;
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 based on 100 parts by weight of the polymer fine particles (A) in total, from the viewpoint of suppressing the change with time of the viscosity of the obtained coating composition. The amount is preferably 0.5 to 10, particularly preferably 1 to 5 parts by weight.

The aqueous resin coating composition of the present invention may further contain, if necessary, an inorganic dispersant [eg, sodium hexametaphosphate, sodium tripolyphosphate, etc.], an organic dispersant [eg, “Knob Cosperse 44C” (trade name). , Polycarboxylic acid type; manufactured by Sannobuco Co., Ltd.]; dispersant such as silicone type; polyvinyl alcohol, cellulose derivative, polycarboxylic acid type resin, thickener such as surfactant type and viscosity improving agent Agents; organic solvents such as ethylene glycol, butyl cellosolve, butyl carbitol, and butyl carbitol acetate; antiaging agents; preservatives and antifungal agents; ultraviolet absorbers; antistatic agents; and the like can be added and mixed.

The aqueous resin coating composition of the present invention is not particularly limited, but is generally about 40 to 90% by weight, preferably about 50 to 85% by weight, particularly preferably about 60 to 80% by weight.
Of solids in the range of 7 to 11, preferably 8 to 10, preferably 8 to 10 and having a pH of about 3,000 to 100,000 cps,
Preferably, it can have a viscosity in the range of about 5,000 to 50,000 cps (Type B rotational viscometer, 25 ° C., 20 rpm).

The base material to which the aqueous resin coating composition of the present invention can be applied is not particularly limited, and examples thereof include steel sheets; for example, lead-tin alloy-plated steel sheets (tan sheet steel sheets), tin-plated steel sheets, and aluminum-plated steel sheets. , Various plated steel sheets such as lead-plated steel sheet, chrome-plated steel sheet, nickel-plated steel sheet; coated steel sheet such as electrodeposition coated steel sheet: and the like.

The coating composition of the present invention is, in particular, one obtained by forming such a base material into various shapes by a sheet metal press or the like and welding the same as various automobile members, for example, an automobile gasoline tank, an underfloor, Tire house,
It can be suitably used for coating an electrodeposition coated surface, an intermediate coating surface or a top coating surface of a sheet metal working member such as a front apron and a rear apron outside the vehicle.

The coating composition of the present invention can be coated by a coating method known per se, for example, brush coating, spray coating, roller coating, etc., but airless spray coating is generally preferable.

The coating film thickness at that time varies depending on the application of the base material, etc., but is usually in the range of about 200 to 800 .mu.m, preferably about 300 to 600 .mu.m. Further, the coating film can be dried by natural drying, heat drying, etc., but generally in the case of an aqueous resin coating composition for low temperature baking, baking is performed in a heating furnace at a temperature of about 60 to 100 ° C. In the case of an aqueous resin coating composition for high temperature baking, it is convenient to pre-dry at a temperature of about 60 to 100 ° C and then to bake in a heating furnace at a temperature of about 120 to 160 ° C. .

[0172]

EXAMPLES The present invention will be described in more detail below with reference to examples.

The preparation of test samples used in Examples and Comparative Examples and the test method therefor are as follows.

(1) Preparation of test piece Nippon Steel Paint Co., Ltd.
Steel plate (hereinafter referred to as ED plate) that has been electrodeposited using the cation electrodeposition paint "U-600" manufactured by K.K., 0.8 mm x 100 mm x 200 mm
Then, each sample is coated by an airless spray coating method so that the dry coating film has a predetermined thickness, and heat-treated under predetermined conditions using a hot-air circulating dryer.

(2) Blister limit film thickness In spray coating in the above (1), coating is performed by changing the thickness of the dry coating film, and the maximum film thickness that does not cause blistering during drying is obtained. Be thick.

(3) Crack limit film thickness In spray coating in the above item (1), coating is performed by changing the thickness of the dry coating film, and the maximum film thickness that does not cause cracks during drying is obtained. Be thick.

(4) Adhesion test In the previous item (1), a test piece obtained by coating so as to have a dry film thickness of about 500 μ was used as a goggles tester [Suga Tester Co., Ltd.].
By making a cut line having a depth reaching the base material at intervals of 1 mm in each of the vertical and horizontal directions from the coated surface, 100 crevices are created in 1 cm ² . A cellophane tape with a width of 24 mm (manufactured by Nichiban Co., Ltd.) is pasted on this gobang, and the film is rapidly peeled by 180 ° by hand, and the number of eyes remaining in the coating film is counted and displayed as the number of remaining coating film / 100.

(5) Normal-state chipping resistance test In the previous item (1), the test piece obtained by coating so as to have a dry film thickness of about 500 μ was left for 16 hours under a constant temperature condition of about 25 ° C. Using an office cutter, insert a cut line of 5 cm in length to reach the base material from the surface of the coating film.

The test piece was stood upright at an angle of 60 ° with respect to the horizontal plane and fixed, and the coated surface was vertically raised from a height of 2 m.
Using a 25 mmφ PVC pipe, continuously drop the nut (M-6) aiming at the part where the creases were made, and evaluate the total weight of the dropped nut when the base material of the ED board was exposed.

(6) 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 500 μ was immersed in deionized water at about 40 ° C. for 7 days and then taken out. Then wipe off the water and then make a square pattern like the previous (4) and leave it at 25 ° C for 3 hours.
Perform a chipping resistance test in the same manner as in Section 1 above, and make the same evaluation.

(7) Low temperature impact resistance test In the previous section (1), the test piece was left under constant temperature condition of -30 ° C for 3 hours or more, and then subjected to Dubon type impact resistance test according to JIS K 5400. To do.

The condition at this time is that the radius of the tester is 6.35 ± 0.3.
Attach a 3mm shooting die and pedestal, sandwich the test piece with the coating surface facing upwards, and put a weight of 500 ± 1g on 50cm.
It is dropped on the shooting mold from the height of and the degree of damage of the coating film surface is visually evaluated according to the following evaluation criteria.

◎ ・ ・ ・ ・ No change at all ○ ・ ・ ・ ・ ・ ・ Slightly small cracks occurred △ ・ ・ ・ ・ ・ ・ Small cracks occurred frequently × ・ ・ ・ ・ Large cracks occurred

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 heated 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. 485 parts by weight of styrene (St) and acrylic acid (AA) ) A monomer mixture liquid in which 15 parts by weight is uniformly mixed is added dropwise and stirred to prepare a monomer pre-emulsion, and a 5 wt% aqueous solution of ammonium persulfate (APS) is used as the pre-emulsion and the polymerization initiator aqueous solution. Parts by weight are continuously added over 3 hours, and then kept at the same temperature for 1 hour,
4 ml of 25 wt% ammonia water was added to obtain a styrene copolymer emulsion.

Table 5 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 particles during this polymerization.

Reference Example 2 In Reference Example 1, instead of using 485 parts by weight of St, St
435 parts by weight and 2-hydroxyethyl methacrylate (H
EMA) except that 50 parts by weight is used,
A styrene copolymer emulsion was obtained. Table 5 shows the monomer composition during the polymerization, the solid content of the obtained copolymer emulsion, the pH, the viscosity, the particle size, and the Tg of the copolymer particles.

Reference Example 3 An acrylic copolymer emulsion was obtained in the same manner as in Reference Example 1 except that 485 parts by weight of methyl methacrylate (MMA) was used instead of 485 parts by weight of St. Monomer composition during the polymerization, solid content of the obtained copolymer emulsion, pH, viscosity, particle size, and,
Table 5 shows the Tg of the copolymer particles.

Reference Example 4 In Reference Example 1, instead of using 485 parts by weight of St, St
360 parts by weight and 2-ethylhexyl acrylate (EHA)
A styrene-acrylic copolymer emulsion was obtained in the same manner as in Reference Example 1 except that 125 parts by weight was used. Table 5 shows the monomer composition during the polymerization, the solid content of the obtained copolymer emulsion, the pH, the viscosity, the particle size, and the Tg of the copolymer particles.

Reference Example 5 In Reference Example 1, instead of using 485 parts by weight of St, St
A styrene-acrylic copolymer emulsion was obtained in the same manner as in Reference Example 1 except that 320 parts by weight, 50 parts by weight of HEMA and 115 parts by weight of EHA were used. Monomer composition during this polymerization, solid content of the obtained copolymer emulsion, pH,
Table 5 shows the viscosity, particle size, and Tg of the copolymer particles.

[0190]

[Table 5]

Example 1 Commercially available SBR-based polymer emulsion "SN-562" [Sumitomo Dow
Co., Ltd .: Tg-40 ° C., viscosity 170 cps, pH 7.1, solid content 52.
5 parts by weight, particle size 0.16μ] 133 parts by weight (about 70 parts by weight of solid content) and 60 parts by weight of the styrene-based copolymer emulsion of Reference Example 1 (about 30 parts by weight of solid content), as a dispersant "NOBUCO" Sparse 44C "(manufactured by San Nobuco Co., Ltd., polycarboxylic acid type) 2.0 parts by weight (solid content: about 0.88 parts by weight), powdered calcium carbonate [" SL-700 ", average particle size: 4.5μ, Takehara Chemical Industries, Ltd. as an inorganic filler KK] 115 parts by weight, light calcium carbonate [Maruo Calcium Co., Ltd .; major axis about 2.0μ, minor axis about 0.4μ] 100 parts by weight, "Matsumoto Microsphere F-50" as heat-expandable polymer beads [Product name: manufactured by Matsumoto Yushi-Seiyaku Co., Ltd .; water content: about 30% by weight; particle size before thermal expansion: 10
~ 20μ; particle size after thermal expansion 30 ~ 80μ; softening temperature of shell wall 10
0 to 105 ° C.] 3 parts by weight (main body weight excluding water, about 2.1 parts by weight, including the weight of the organic solvent as the heating vaporizing type foaming agent), 3 parts by weight of carbon black and 12 parts by weight of barium metaborate are added to the disperser. Disperse evenly by using "Adekanol UH-472" as a thickener [Asahi Denka
Co., Ltd.] 0.5 part by weight is added and further stirred, and the total pigment (powdered calcium carbonate, light calcium carbonate, heat-expandable polymer beads or hollow beads, carbon black and barium metaborate) occupying in the coating film is added. A chipping-resistant aqueous resin coating composition having a ratio of 70% by weight (hereinafter sometimes abbreviated as PWC) and a solid content of 77.7% by weight was prepared.

Various physical property tests were carried out using the obtained aqueous resin coating composition. The composition of the composition is shown in Table 6, and the measurement results of the properties and various physical properties of the composition are shown in Table 7.
The coating film was subjected to high-temperature baking treatment (preliminary drying at 80 ° C for 15 minutes and then baking at 120 ° C for 20 minutes) using a hot air circulation dryer.

Comparative Example 1 A chipping-resistant aqueous resin coating having a PWC content of 70% by weight was prepared in the same manner as in Example 1 except that the thermally expandable polymer beads "Matsumoto Microsphere F-50" were not used. A composition was made.

Various physical property tests were conducted in the same manner as in Example 1 by using the obtained aqueous resin coating composition. The composition of the composition is shown in Table 6, and the measurement results of the properties and various physical properties of the composition are shown in Table 7.

Examples 2-3 In place 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" are used.
[Brand name: manufactured by Nippon Philite Co., Ltd .; moisture content of about 85% by weight;
12 parts by weight of particle diameter (about 40μ) (about 1.
8 parts by weight) or glass beads "Scotchlight B3
8/4000 ”(trade name: manufactured by Sumitomo 3M Ltd., average particle density 0.38 g / cc) is used in an amount of 10 parts by weight, and calcium carbonate“ SL-
An acrylic resin aqueous coating composition was prepared in the same manner as in Example 1 except that the amount of "700" used was adjusted.

Various physical property tests were conducted in the same manner as in Example 1 by using the obtained aqueous resin coating composition. The composition of the composition is shown in Table 6, and the measurement results of the properties and various physical properties of the composition are shown in Table 7.

Examples 4 to 5 In the same manner as in Example 1 except that the copolymer emulsions of Reference Examples 2 to 3 were used instead of the styrene-based copolymer emulsion of Reference Example 1 in Example 1. ,
A chipping resistant aqueous resin coating composition having a PWC of 70% by weight was prepared.

Using the obtained aqueous resin coating composition, test pieces were prepared in the same manner as in Example 1 and various physical properties tests were conducted.
The composition of the composition is shown in Table 6, and the measurement results of the properties and various physical properties of the composition are shown in Table 7.

Example 6 In Example 4, except that 4 parts by weight (solid content: about 1 part by weight) of aziridine compound "SU-125F" [trade name; manufactured by Meisei Chemical Industry Co., Ltd.] was used as a crosslinking agent. In substantially the same manner as in Example 1, a chipping-resistant aqueous resin coating composition having a PWC content of 70% by weight was prepared.

Using the obtained aqueous resin coating composition, test pieces were prepared in the same manner as in Example 1 and various physical properties tests were conducted.
The composition of the composition is shown in Table 6, and the measurement results of the properties and various physical properties of the composition are shown in Table 7.

Example 7 In Example 1, the SBR polymer emulsion "SN-56
2 ”133 parts by weight (about 70 parts by weight of solids) and 60 parts by weight of the styrene copolymer emulsion of Reference Example 1 (about 30 parts by weight of solids) are used instead of the SBR-based polymer emulsion“ SN- 562 "114 parts by weight (about 60 parts by weight of solid content), 60 parts by weight of the styrene-based copolymer emulsion of Reference Example 1 (about 30 parts by weight of solid content) and commercially available urethane resin emulsion" M-589 "[ Toyo Polymer Co., Ltd.] A chipping-resistant aqueous resin coating composition having PWC of 70% by weight was prepared in substantially the same manner as in Example 1 except that 33 parts by weight (about 10 parts by weight of solid content) was used.

Using the obtained aqueous resin coating composition, test pieces were prepared in the same manner as in Example 1 and various physical properties tests were conducted.
The composition of the composition is shown in Table 6, and the measurement results of the properties and various physical properties of the composition are shown in Table 7.

Comparative Example 2 Example 7 was repeated except that the thermally expandable polymer beads "Matsumoto Microsphere F-50" were not used but the amount of calcium carbonate "SL-700" was increased by that amount.
A chipping-resistant water-based resin coating composition having a PWC content of 70% by weight was prepared in the same manner as in.

Using the obtained aqueous resin coating composition, test pieces were prepared in the same manner as in Example 1 and various physical properties tests were conducted.
The composition of the composition is shown in Table 6, and the measurement results of the properties and various physical properties of the composition are shown in Table 7.

Examples 8 to 9 In Example 7, instead of using 3 parts by weight of the heat-expandable polymer beads "Matsumoto Microsphere F-50", hollow polymer beads "Expancel WE ^# 551" were used.
With 12 parts by weight or 10 parts by weight of hollow inorganic beads "Scotchlite B38 / 4000".
A chipping-resistant aqueous resin coating composition was prepared in the same manner as in Example 7, except that the amount of "00" used was adjusted.

Various physical property tests were carried out in the same manner as in Example 1 by using the obtained aqueous resin coating composition. The composition of the composition is shown in Table 6, and the measurement results of the properties and various physical properties of the composition are shown in Table 7.

Examples 10 to 11 In the same manner as in Example 7 except that the copolymer emulsions of Reference Examples 2 to 3 were used instead of the styrene copolymer emulsion of Reference Example 1 in Example 7. ,
A chipping resistant aqueous resin coating composition having a PWC of 70% by weight was prepared.

Using the obtained aqueous resin coating composition, test pieces were prepared in the same manner as in Example 1 and various physical properties tests were conducted.
The composition of the composition is shown in Table 6, and the measurement results of the properties and various physical properties of the composition are shown in Table 7.

Example 12 PWC was measured in the same manner as in Example 10 except that 4 parts by weight of aziridine compound "SU-125F" (about 1 part by weight of solid content) was used as a crosslinking agent. A wt% chipping resistant aqueous resin coating composition was prepared.

Using the obtained aqueous resin coating composition, test pieces were prepared in the same manner as in Example 1 and various physical properties tests were conducted.
The composition of the composition is shown in Table 6, and the measurement results of the properties and various physical properties of the composition are shown in Table 7.

[0211]

[Table 6]

[0212]

[Table 7]

Example 13 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.
Example 1 except that 12 parts by weight was used and the styrene-acrylic copolymer emulsion of Reference Example 4 was used instead of the styrene copolymer emulsion of Reference Example 1.
A chipping-resistant water-based resin coating composition having a PWC content of 70% by weight and a solid content of 75.6% by weight was prepared in substantially the same manner as in.

Various physical property tests were carried out using the obtained aqueous resin coating composition. Table 8 shows the composition of the composition, and Table 9 shows the measurement results of the properties and various physical properties of the composition.
The coating film was subjected to low temperature baking treatment (baking at 80 ° C for 30 minutes) using a hot air circulation dryer.

Comparative Example 3 The same as Example 13 except that the hollow polymer beads “Expancel WE ^# 551” were not used but the amount of calcium carbonate “SL-700” was increased. Similarly, a chipping-resistant aqueous resin coating composition having a PWC content of 70% by weight was prepared.

Using the obtained aqueous resin coating composition, various physical properties tests were conducted in the same manner as in Example 13. Table 8 shows the composition of the composition, and Table 9 shows the measurement results of the properties and various physical properties of the composition.

Example 14 In Example 13, 10 parts by weight of hollow inorganic beads "Scotchlite B38 / 4000" were used in place of 12 parts by weight of hollow polymer beads "Expancel WE ^# 551", and calcium carbonate was used. PWC was 70% by weight and the solid content was 7% as in Example 13 except that the amount of "SL-700" was adjusted.
A 8.4 wt% chipping resistant aqueous resin coating composition was prepared.

Using the obtained aqueous resin coating composition, various physical properties tests were conducted in the same manner as in Example 13. Table 8 shows the composition of the composition, and Table 9 shows the measurement results of the properties and various physical properties of the composition.

Example 15 PWC was prepared in the same manner as in Example 13 except that the copolymer emulsion of Reference Example 5 was used instead of the styrene-acrylic copolymer emulsion of Reference Example 4. 70% by weight of a chipping-resistant aqueous resin coating composition was prepared.

Using the obtained aqueous resin coating composition, a test piece was prepared in the same manner as in Example 13 and various physical properties tests were conducted.
Table 8 shows the composition of the composition, and Table 9 shows the measurement results of the properties and various physical properties of the composition.

Example 16 A PWC was prepared in the same manner as in Example 15 except that 4 parts by weight of aziridine compound "SU-125F" (solid content: about 1 part by weight) was further used as a crosslinking agent. A wt% chipping resistant aqueous resin coating composition was prepared.

Using the obtained aqueous resin coating composition, test pieces were prepared in the same manner as in Example 13 and various physical properties tests were conducted.
Table 8 shows the composition of the composition, and Table 9 shows the measurement results of the properties and various physical properties of the composition.

Example 17 In Example 13, the SBR polymer emulsion "SN-56
2 "Instead of using 133 parts by weight (about 70 parts by weight of solids) and 60 parts by weight of the styrene-acrylic copolymer emulsion of Reference Example 4 (about 30 parts by weight of solids), an SBR-based polymer emulsion" SN-562 "95 parts by weight (solid content: about 50 parts by weight), styrene-acrylic copolymer emulsion of Reference Example 4 40 parts by weight (solid content: about 20 parts by weight) and commercially available urethane resin emulsion" M -589 "A chipping-resistant aqueous resin coating composition having a PWC content of 70% by weight was prepared in substantially the same manner as in Example 13 except that 100 parts by weight (about 30 parts by weight of solid content) was used.

Using the obtained aqueous resin coating composition, a test piece was prepared in the same manner as in Example 13 and various physical properties tests were conducted.
Table 8 shows the composition of the composition, and Table 9 shows the measurement results of the properties and various physical properties of the composition.

Comparative Example 4 The same as Example 17 except that the hollow polymer beads “Expancel WE ^# 551” were not used but the amount of calcium carbonate “SL-700” was increased by that amount. A chipping resistant waterborne resin coating composition having a PWC content of 70% by weight was prepared in substantially the same manner.

Using the obtained aqueous resin coating composition, a test piece was prepared in the same manner as in Example 13 and various physical properties tests were conducted.
Table 8 shows the composition of the composition, and Table 9 shows the measurement results of the properties and various physical properties of the composition.

Example 18 In Example 17, 10 parts by weight of hollow inorganic beads "Scotchlite B38 / 4000" were used instead of 12 parts by weight of hollow polymer beads "Expansel WE ^# 551", and calcium carbonate was used. PWC was 70% by weight and the solid content was 7% as in Example 13 except that the amount of "SL-700" was adjusted.
A 1.0 wt% chipping resistant aqueous resin coating composition was prepared.

Using the thus obtained aqueous resin coating composition, various physical properties tests were conducted in the same manner as in Example 13. Table 8 shows the composition of the composition, and Table 9 shows the measurement results of the properties and various physical properties of the composition.

Example 19 PWC was prepared in substantially the same manner as in Example 17, except that the copolymer emulsion of Reference Example 5 was used instead of the styrene-acrylic copolymer emulsion of Reference Example 4. 70% by weight of a chipping-resistant aqueous resin coating composition was prepared.

Using the obtained aqueous resin coating composition, test pieces were prepared in the same manner as in Example 13 and various physical properties tests were conducted.
Table 8 shows the composition of the composition, and Table 9 shows the measurement results of the properties and various physical properties of the composition.

Example 20 A PWC was prepared in the same manner as in Example 19 except that 4 parts by weight of aziridine compound "SU-125F" (about 1 part by weight of solid content) was further used as a crosslinking agent. A wt% chipping resistant aqueous resin coating composition was prepared.

Using the obtained aqueous resin coating composition, a test piece was prepared in the same manner as in Example 13 and various physical properties tests were conducted.
Table 8 shows the composition of the composition, and Table 9 shows the measurement results of the properties and various physical properties of the composition.

[0233]

[Table 8]

[0234]

[Table 9]

[0235]

The aqueous resin coating composition of the present invention comprises a specific synthetic rubber emulsion polymer particle as a vehicle component.
(A-1) and emulsion polymer particles having a specific glass transition temperature (A-2) as an essential component, if necessary a mixture of urethane resin emulsion particles (A-3) in a specific amount By further blending the heat-expandable polymer beads and / or hollow beads (C) together with the usual inorganic filler (B), a usual synthetic rubber-based copolymer latex, an acrylic-based copolymer emulsion or their Excellent physical properties that cannot be achieved by using blends, that is,

Chipping resistance at room temperature and extremely low temperatures such as −30 ° C., especially when the coating film is wet; metalworking members, particularly coating such as cationic electrodeposition coated steel sheet. Excellent adhesion to metal-working parts where the composition is relatively difficult to adhere to; flat and uniform film forming property; water resistance; gasoline resistance; impact resistance; soundproofing and other chipping-resistant coating composition While combining various properties in a well-balanced manner,

For example, even when an extremely thick coating film having a thickness of 600 μm or more is formed, the drying process does not cause blister and other inconveniences, and further, a fibrous or heteromorphic inorganic filler such as light calcium carbonate or heteromorphic calcium carbonate is filled. By blending the agent, it is possible to obtain an excellent aqueous resin coating composition that can prevent the occurrence of cracks in the coating film that are likely to occur due to rapid drying shrinkage during heating and drying.

[Chemical 2]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C09D 5/08 PPX 6904-4J PQA 6904-4J 133/04 PGE 7921-4J 133/20 PFW 7921- 4J 175/04 PHX 8620-4J // (C09D 109/00 133: 06 7921-4J 125: 04 9166-4J 133: 20) 7921-4J (72) Inventor Ryoji Takahata 3 Yokodai, Isogo-ku, Yokohama, Kanagawa Prefecture −24−26 Nippon Carbide Industry Co., Ltd. Yokohama Dormitory

Claims (1)

[Claims] 1. Polymer fine particles dispersed in an aqueous medium
An aqueous resin coating composition comprising (A) and an inorganic filler (B), wherein the polymer fine particles (A) contain 30 to 90% by weight of (A-1) conjugated diolein unit. Synthetic rubber emulsion polymer particles with glass transition temperature of 0 ° C or less 50-95
% By weight, (A-2) Formula (1), embedded image (In the formula, R ¹ is a hydrogen atom or a methyl group, and Q is —COO.
R ² represents an aryl group having 6 to 12 carbon atoms, or —CN, and R ² represents a lower alkyl group).
5 to 50% by weight of emulsion polymer particles containing 9.9% by weight and having a glass transition temperature of at least 20 ° C., and (A-3) urethane resin emulsion particles, emulsion polymer particles (A-1) and (A- 0 to 100 based on 100 parts by weight of 2)
An aqueous resin coating composition, characterized in that it comprises (C) heat-expandable polymer beads and / or hollow beads.