WO1994011452A1 - Aqueous coating composition - Google Patents

Abstract

An aqueous coating composition containing fine polymer particles (A) and an inorganic filler (B) dispersed in an aqueous medium, wherein the polymer particles (A) comprise: (A-1) 50-100 wt. % of emulsion polymer particles of a synthetic rubber containing 30-90 wt. % of conjugated diolefin units and having a glass transition point of 0 °C or below; (A-2) 0-50 wt. % of emulsion polymer particles containing 30-99.9 wt. % of repeating units represented by general formula (I), (wherein R1 represents hydrogen or methyl; Q represents -COOR2, C6-C12 aryl or CN; and R2 represents lower alkyl) and having a glass transition point of at the lowest of 200 °C; and (A-3) 0-100 parts by weight of urethane resin emulsion particles per 100 parts by weight in total of the polymer particles (A-1) and (A-2), and the composition further contains: (C) an isocyanate derivative as a cross-linking agent. This composition is used as mastic coating material, soundproof coating material, vibrationproof coating material, caulking material, and the like. In particular, it is used to protect worked outdoor sheet metal members of vehicles, especially, automotive underfloor panel, tire house, chassis, gasoline tank, suspension, and so on from chipping or scratches caused by spattered stones, because it is excellent in various performances including chipping resistance, tight bonding to worked metallic member, uniformness and smoothness of coating, water resistance, gasoline resistance, impact resistance and soundproofness, and low-temperature characteristics such as chipping resistance at a temperature as extremely low as -30 °C or below.

Description

 Description-Water-borne coating composition

【Technical field】

 The present invention relates to an aqueous coating composition, and more particularly, for example, to an aqueous dispersion type coating composition such as a masking paint, a soundproofing paint, a vibration damping paint, a caulking material, etc. Tire house, chassis, gasoline tank, suspension, etc., used to protect the metal processing member from scratches caused by stepping stones and so-called "chipping" of the metal processing member. Excellent in various properties such as adhesion, uniformity and lubricity of the coating, water resistance, gasoline resistance, impact resistance, soundproofing, and impact resistance at extremely low temperatures of 130 ° C or lower. The composition is based on synthetic rubber-based emulsion polymer particles with excellent low-temperature properties, and contains an isocyanate derivative as a cross-linking agent. Related.

 [Background Art]

Conventionally, a water-based resin dispersion such as a rubber-based latex / a grille-based copolymer emulsion has been used as a vehicle as a water-based anti-chipping-resistant coating agent used for outdoor metal processing members of vehicles such as automobiles. Compounds containing an inorganic filler such as talc are known. For example, those based on an aqueous dispersion of an acrylic copolymer aqueous resin are disclosed in, for example, Japanese Patent Publication No. 53-64287, Japanese Unexamined Patent Publication No. Sho 59-755954, Japanese Unexamined Patent Application Publication No. Sho 62-23068, Japanese Unexamined Patent Application Publication No. It is disclosed in, for example, Japanese Patent Application Publication No. ·

 However, the water-based coating agent for anti-chipping described in these publications has an anti-chipping property at room temperature (hereinafter, may be referred to as “normal anti-chipping property”), and an anti-chipping property immediately after being wetted with water (hereinafter, referred to as “anti-chipping property”). "Wet chipping resistance"), excellent adhesion to metal workpieces, impact resistance, especially impact resistance at extremely low temperatures of, for example, 130 ° C or less (hereinafter referred to as “low temperature impact resistance”). It is not easy to satisfy both the properties as a coating for anti-tipping and the anti-swelling property in the drying process when forming a thick film such as 600 or more. However, if the amount of the inorganic filler in the coating material is reduced in order to improve the normal chipping resistance and the low-temperature impact resistance, blisters (b1 ister) are likely to be generated in the baking process. Increasing the amount of the filler to prevent blisters has the problem that the chipping resistance under normal conditions and the low-temperature impact resistance are significantly reduced. For example, a method of assembling a body, a chassis, and the like, and then performing cationic electrodeposition coating on the entire body by “doping” is often adopted. Such a metal workpiece coated with cationic electrodeposition is described in the above-mentioned publication. When coated with a coating agent for chipping resistance, the adhesion of the coating agent tends to be insufficient, and the wet chipping resistance tends to be significantly reduced.

 On the other hand, a water-based coating for anti-chipping using a rubber-based latex as a vehicle is disclosed in, for example, JP-A-57-180617, JP-A-59-75954, It is disclosed in Japanese Patent Application Laid-Open No. 59-12992, for example.

O However, these publications do not disclose or suggest that an isocyanate derivative is contained as a cross-linking agent. Therefore, the water-based coating agent for chipping resistance using the latex described in these publications is also subject to normal and wet conditions. There is a problem that both the chipping resistance and the low-temperature impact resistance are not always satisfactory.

 Further, as a vehicle, an aqueous coating agent for anti-tipping using a rubber-based latex mixed with another copolymer is also known.

In Japanese Patent Application Publication No. 54-512139, specific amounts of styrene-butadiene copolymer resin, vinyl chloride-vinyl acetate-unsaturated dibasic acid copolymer resin and low molecular weight liquid polymer were blended as vehicles. It has been proposed to use one.

 However, in the above-mentioned publication, the vinyl chloride-vinyl acetate-unsaturated dibasic acid copolymer resin is usually in the form of powder, but the copolymer resin powder is not easily dispersed, and the It was found that the resulting coating did not have sufficient adhesion to the metal-worked member and had insufficient chipping resistance.

 Further, for example, in Japanese Patent Application Laid-Open No. 2-28269, as a base resin (vehicle component) in an aqueous coating agent for anti-chipping, it is formed by emulsion polymerization of styrene, butadiene and acryl-based monomers. It has been proposed to use a copolymer having a glass transition temperature of 0 ° C. or lower 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 publication, the base resin is prepared by emulsion polymerization of an acryl-based monomer in the presence of styrene-butadiene rubber latex. According to the method described in the examples An attempt was made to prepare a copolymer by emulsion polymerization of acryl-based monomers in the presence of styrene-butadiene rubber latex, with respect to residual double bonds derived from butadiene units in the rubber latex. Since the acryl-based monomer was subjected to graft polymerization, a copolymer having the desired rubber elasticity was not obtained, and only a hard and brittle copolymer was obtained.

 Furthermore, coating of chipping-resistant coatings on parts other than the body, such as the chassis, gasoline tanks, suspensions, etc. of automobile parts is generally performed on a separate line from the body coating line. Attempts have been made to reduce the baking temperature of the coating film on the coating line to a relatively low temperature, for example, 10 ° C. or less, in order to reduce the cost of manufacturing automobiles. Although it has the advantage that the problem can be almost avoided, it has also been found that there is the problem that the adhesion of the coating to these parts is further reduced.

The present inventors have developed a coating agent for anti-tibbing such as normal and wet anti-chipping properties, low-temperature impact resistance, adhesion to a substrate surface, uniformity and smoothness of a coating film, water resistance and solvent resistance. It has a good balance of various characteristics as well as excellent resistance to chipping even when forming a thick film on metal workpieces that are subjected to high-temperature baking such as automobile bodies. Intensive research was conducted for the purpose of providing a composition for a bing-based aqueous coating. Further, the present invention is a composition for water-resistant coating, which is mainly used for coating a metal working member such as a part other than the automobile body, and has a coating film baking temperature of, for example, 10 ° C. or less. Even at low temperatures, it does not impair the adhesion of the paint film to the substrate surface, which tends to deteriorate, and has a good balance of the other properties described above as a coating for anti-tipping. Further studies were conducted with the aim of providing a composition for aqueous coating with anti-chipping properties.

 As a result, a synthetic rubber-based emulsion polymer having a glass transition temperature (hereinafter, sometimes referred to as Tg) of 0 ° C or less was used as a vehicle component of the aqueous coating composition, and an isocyanate derivative was used as a crosslinking agent. The inventor has found that the above object can be achieved by including the compound, and has completed the present invention.

 Further, as the vehicle component, together with the synthetic rubber-based emulsion polymer, a certain specific emulsion polymer having a relatively high Tg of 20 ° C or higher (hereinafter referred to as a high Tg emulsion weight). By using them together, it was possible to further improve the physical properties of the coating, such as anti-swelling properties, substrate adhesion, normal and wet chipping resistance, and low-temperature impact resistance.

 In addition, when the urethane-based emulsion polymer is used in combination with the above two emulsion polymers as the vehicle component, the wet coating composition has an excellent wet-tipping resistance, and a metal-processed 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.

 Further, by using the above-mentioned one to three kinds of emulsion polymers as a vehicle component and containing white carbon as an inorganic filler, the anti-swelling property, the normal state, and the wet chipping resistance could be further improved.

Further, the above-mentioned one to three kinds of emulsion polymers are used as a vehicle component, and together with the above-mentioned crosslinking agent and inorganic filler, for example, heating at about 110 ° C. More expandable heat-expandable polymer beads or hollows.The inclusion of beads can reduce the weight of the resulting coating, and further improve light-proof calcium carbonate and irregular shapes to further improve anti-swelling properties and low-temperature impact resistance. Even if fibrous or modified inorganic fillers such as calcium carbonate are blended, the use of these fillers prevents problems such as film cracks due to rapid drying shrinkage during drying, which are usually caused by the use of these fillers. Was found. The anti-chipping agent containing the above-mentioned heat-expandable polymer beads or hollow beads is known per se, and is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 62-100,650 and 62-2-2. JP-A-6-08767, JP-A-3-218977, JP-A-4-538778, JP-A-4-81477, etc. An anti-chipping agent in which organic or inorganic hollow beads are contained in a plastisol of a vinyl resin is disclosed.

 However, all of these anti-chipping agents are not water-based anti-chipping agents, and problems such as application of the anti-chipping agents and environmental hygiene cannot be avoided. The use of a vinyl chloride resin has many problems during processing and the like.

 Also, for example, JP-A-64-81664 discloses a chipping-resistant agent containing a copolymer resin containing a conjugated diolefin unit and an aromatic vinyl monomer unit, and a heat-expandable polymer bead. Is disclosed. This copolymer resin is likely to be an aqueous latex, as estimated from the formulation of the example.

However, the above-mentioned Japanese Patent Application Laid-Open No. S64-81864 does not disclose the use of a cross-linking agent at all. Has insufficient cohesion of the coating, It turned out that it was completely inadequate in terms of bingability. The isocyanate derivative of the cross-linking agent, which is an essential component in the present invention, improves this point and has various properties as a composition for an aqueous coating composition having anti-chipping properties.

 DISCLOSURE OF THE INVENTION

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

 (A-1) 50 to 100% by weight of synthetic rubber-based emulsion polymer particles containing 30 to 90% by weight of conjugated diolefin units and having a glass transition temperature of 0 ° C. or less; and

 (A-2) Formula

Where:

R ¹ represents a hydrogen atom or a methyl group,

Q represents a Ariru group or one CN single COOR ^2, C ₆ ~ _12, wherein

R ² represents a lower alkyl group,

R ³ represents a hydrogen atom or a lower alkyl group,

(A-3) urethane resin emulsion particles containing 30 to 99.9% by weight of a unit represented by the following formula and having a glass transition temperature of at least 20 ° C .: 0 to 50% by weight; 100 to 100 parts by weight of the total amount of particles (A-1) and (A-2)

(U-corrected paper 1U91) And, as a crosslinking agent,

 (C) an isocyanate derivative,

The composition for aqueous coating characterized by containing is provided.

 In the present specification, the expression “emulsion polymer particles” refers to polymer fine particles dispersed in an aqueous medium and has an average particle diameter of usually 1 m or less, preferably 0.05 μm or less. It means dispersed particles of about 0.5 im, and does not necessarily mean only polymer particles obtained by emulsion polymerization. In particular, the urethane emulsion polymer particles (A-3) can be produced without emulsion polymerization as described later.

 Hereinafter, the aqueous coating composition of the present invention will be described in more detail. Synthetic rubber-based emulsion polymer particles (A-1)

 The synthetic rubber-based emulsion polymer particles (A-1) constituting one component of the vehicle in the aqueous coating composition of the present invention contain 30 units of conjugated diolefin units based on the weight of the synthetic rubber-based polymer. It is composed of a rubber-elastic copolymer which is contained in a proportion of up to 90% by weight, preferably 40 to 80% by weight, and more preferably 45 to 75% by weight.

 Such a synthetic rubber-based copolymer can be produced according to a method similar to a known method for producing a synthetic rubber-based copolymer latex, for example,

 (a-1) a conjugated diolefin monomer;

 (a-2) aromatic vinyl monomer and Z or vinyl cyanide monomer, preferably

 (a-3) Carboxyl group-containing ethylene monomer

And further as needed (a-4) Other copolymerizable monomers

Along with, it can be formed by aqueous emulsion polymerization under pressure

Ό o

 Examples of the conjugated diolefin monomer (a-1) include one or more monomers selected from butadiene, isoprene, and chloroprene, and the like. Particularly, butadiene is preferable. . Examples of the aromatic vinyl monomer (a-2) include styrene, α-methylstyrene, vinyltoluene, and ethylvinylbenzene. Examples of the vinyl cyanide monomer (a-2) For example, acrylonitrile, methacrylonitrile and the like can be exemplified. These aromatic vinyl monomers and vinyl or cyanide vinyl monomers (a-2) can be used alone or in combination of two or more. Styrene and / or acrylonitrile are particularly preferred.

Furthermore, the carboxyl group-containing ethylene monomer (a-3) used in a suitable case has one or two carboxyl groups in a molecule which can be in a free form or in a salt or anhydride form. shed, ethylenically unsaturated monomers are included, for example, acrylic acid, methacrylic acid, C ₃ ~ ₅ a such black tonnes acid / 3 - unsaturated monocarboxylic acid; citraconic acid, itaconic acid, maleic acid , C ₄ ~ ₅ a and fumaric acid, yS - unsaturated dicarboxylic acids or their anhydrides or C Bok _{1 2} monoalkyl esters (e.g., Monoe Chiruesuteru, mono - n - or butyl ester); or of carboxylic acids Salts (for example, ammonium salts, alkali metal salts, etc.) can be exemplified. These monomers can be used alone or in combination of two or more. These carboxyl group-containing ethylene monomers Among them, particularly preferred ones include acrylic acid, methacrylic acid and diconic acid.

 The synthetic rubber emulsion polymer particles (A-1) used in the present invention are composed of the conjugated diolefin monomer (a-1) described above and an aromatic vinyl monomer and / or vinyl cyanide monomer. The compound (a-2) can be produced as an essential monomer component, and more preferably a copolymer obtained by combining and copolymerizing a carboxyl group-containing ethylene monomer with the synthetic rubber-based copolymer. If necessary, as is often the case in the production of coalesced latex, other monomers can be copolymerized.

 Examples of such other copolymerizable monomers (a-4) include the following.

① Ester of acrylic acid or methacrylic acid: For example, methyl acrylate, ethyl acrylate, n-butyl acrylate, iso-butyl acrylate, n-octyl acrylate, i-octyl acrylate, 2-ethylhexyl acrylate, is 0-Nonyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, n-dodecyl methacrylate _C18 alkyl esters of methacrylic acid.

② Radical polymerizable unsaturated monomer containing at least one crosslinkable functional group: for example, acrylamide, methacrylamide, diacetone acrylamide, N-methylolacrylamide, N-methylolmethacrylamide, etc. Amides of 3-unsaturated carboxylic acids or their derivatives; glycidyl acrylate, glycidyl methacrylate, etc. Esters of rubonic acid with a saturated alcohol having an epoxy group; 2-hydroxyshethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyshethyl methacrylate, 2-hydroxypropyl methacrylate Esters of S-unsaturated carboxylic acids and polyhydric saturated alcohols, such as acrylates; and yS-unsaturated carboxylic acids and amino groups, such as dimethylaminoethyl methacrylate and getylaminoethyl methacrylate. Esters with saturated alcohols having: divinylbenzene, diarylphthalate, triallyl cyanurate, ethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate , Diethylene glycol dimethacrylate, aryl methacrylate, etc. Monomer having a body unsaturated group: etc.

 The proportion of the monomer components (a-1) to (a-4) described above depends on the physical properties and the like required for the synthetic rubber-based emulsion polymer particles (A-1) to be formed. Although it can be changed in a wide range, it can usually be used within the range shown below.

 General range Preferred range More preferred monomer (% by weight) (% by weight) Range (% by weight)

(a 1) 30-90 40-80 45-75

 (a 2) 10-70 15〜 55 20-50

 (a 3) 0.1-10 0.5-5 1-4

 (a 4) 0 ~ 200 0 ~ 0 ~ 5

 Note: The weight percentages are percentages based on the total amount of monomers.

The synthetic rubber-based latex polymer particles (A-1) combine the monomer components (a-1) to (a-4) described above with a synthetic rubber-based latex known per se. In the same manner as in the process for preparing a liposome, about 30 to about 100 ° C., preferably about 40 to about 100 ° C. in an aqueous medium in the presence of a surfactant and, if necessary, in the presence of a protective color. It can be produced by emulsion polymerization at a temperature of 90 ° C, usually under pressure.

As the surfactant, any type of nonionic, anionic, cationic or amphoteric surfactant can be used. As nonionic surfactants, for example, polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; polyoxyethylene octyl phenol ether, polyoxyethylene nonyl phenol ether Sorbitan monolaurate, sorbitan monostearate, sorbitan fatty acid esters such as sorbitan trioleate; polyoxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate Polyoxyalkylene fatty acid esters such as polyoxyethylene monolaurate and polyoxyethylene monostearate; monoglyceride oleate and monostearate Glycerin fatty acid esters such as glyceride; polyquinethylene / polyoxypropylene / block copolymer; and the like. Anionic surfactants include, for example, sodium stearate, sodium sodium oleate, sodium laurate and the like. Fatty acid salts; alkyl aryl sulfone hydrochlorides such as sodium dodecylbenzenesulfonate; alkyl sulfate salts such as sodium lauryl sulfate; sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, polyoxyethylene lauryl sulfosuccinate Alkylsulfosuccinic acid such as sodium acid Ester salts and derivatives thereof; polyoxyalkylene alkyl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate; polyoxyalkylene alkyl aryl ether sulfates such as polyoxyethylene nonyl phenol ether sodium sulfate; and the like. Examples of the cationic surfactant include, for example, alkylamine salts such as laurylamine acetate; quaternary ammonium salts such as laurinoletrimethylammonium chloride and alkylbenzyldimethylammonium chloride. Salt; polyoxitytyl alkylamine; and the amphoteric surfactants include, for example, alkyl betaines such as lauryl betaine. Further, these surfactants are obtained by substituting a part of the hydrogen of the alkyl group with fluorine: a so-called reactive surfactant having a radical copolymerizable unsaturated bond in the molecular structure of these surfactants. And the like can also be used.

 Among these surfactants, non-ionic surfactants include polyoxyalkylene alkyl ethers, polyoxyalkylene alkyl phenol ethers, and anions, from the viewpoint of minimizing the generation of aggregates during emulsion polymerization. As the surfactant, alkyl aryl sulfonates, alkyl sulfates, alkyl sulfosuccinates and derivatives thereof, polyoxyalkylene alkyl ether sulfates, polyoxyalkylene alkyl phenol ether sulfates, and the like are used. Is preferred. These surfactants can be used alone or in an appropriate combination.

The amount of these surfactants used can vary depending on the type of surfactant used, etc., but in general, the sum of the monomer components (a-1) to (a-4) It can be in the range of about 0.5 to about 10 parts by weight per 100 parts by weight, but the polymerization stability of aqueous emulsion polymerization and the storage stability of the resulting synthetic rubber-based polymer emulsion And about 1 to 6 parts by weight, particularly about 1 to 4 parts by weight, from the viewpoint of excellent adhesion to a substrate such as a metal processing member when used in the composition for water-based coating with anti-chipping properties. It is preferable to use within the range. Protective colloids that can be used in the production of synthetic rubber-based polymer emulsions include, for example, polyvinyl alcohols such as partially genated polyvinyl alcohol, fully genated polyvinyl alcohol, and modified polyvinyl alcohol; Cellulose derivatives such as tilcellulose, hydroxypropyl cellulose and carboxymethylcellulose salts; natural polysaccharides such as guar gum;

 The use amount of these protective colloids is not strictly limited, and can be changed according to the kind and the like. Usually, the total amount of the monomer components (a-1) to (a_4) is 1 An amount of about 0 to 3 parts by weight with respect to 100 parts by weight can be exemplified.

 The emulsion polymerization of the monomer components (a-1) to (a-4) is carried out using a polymerization initiator. Examples of the polymerization initiator that can be used include, for example, persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate: organic peroxides such as t-butylhydroxide peroxide, cumenehydroxide peroxide, and p-menthanehydroxide. Substances; hydrogen peroxide; and the like, and these can be used alone or in combination of two or more.

The amount of the polymerization initiator used is not strictly limited, and can be varied in a wide range depending on the type, reaction conditions, and the like. About 0.05 to about 1 part by weight, more preferably about 0.1 to about 0.7 part by weight, particularly preferably about 0.1 part by weight, per 100 parts by weight of the total of the monomer components (a-1) to (a-4). Use amounts such as 0.1 to about 0.5 parts by weight may be exemplified.

 In the emulsion polymerization, a reducing agent can 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; reducing inorganic compounds such as sodium thiosulfate, sodium sulfite, sodium bisulfite, and sodium metabisulfite. Compounds can be exemplified. The amount of these reducing agents used is not particularly limited either, but 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, in the emulsion polymerization, a chain transfer agent can be used if desired. Such chain transfer agents, for example, Shiano acetate: C Bok ₈ alkyl esters of Xia Roh acetate; C Bok ₈ § alkyl ester such bromoacetic acid; bromoacetate en anthracene, Fouesnant train, fluorene, 9 - full Polycyclic aromatic compounds such as enylfluorene; aromatic nitro compounds such as P-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol, P-nitrotoluene; penzoquinone; Benzoquinone derivatives such as 2,3,5,6-tetramethylbenzoquinone; borane derivatives such as tributylborane: carbon tetrabromide, carbon tetrachloride, 1,1,2,2-tetrabromoethane, tribromo Halogenated hydrocarbons such as ethylene, trichloroethylene, bromotrichloromethane, tribromomethane, 3-chloro-1-propene; Loral, § such as Furarudehi de Aldehydes; for example, C ₁₈ alkyl mercaptans such as n-dodecyl mercaptan; aromatic mercaptans such as thiophenol and toluene mercaptan; mercaptoacetic acid; C ₁₀ alkyl esters of mercaptoacetic acid; 2-mercaptoethanol C Medicine ₁₂ inhibit mud kill alkyl Melka butanes such as Le; Binen, terpenes such Tapinoren; and the like.

 When the above chain transfer agent is used, the amount thereof is preferably in the range of about 0.005 to about 3.0 parts by weight based on 100 parts by weight of the total of the monomers (a-1) to (a-4).

 The synthetic rubber polymer emulsion (latex) formed by the emulsion polymerization described above generally has a content of 10 to 70% by weight, preferably 30 to 65% by weight, and more preferably 40 to 60% by weight. The solids content is typically less than 10,000 cps, especially about 50 to about 5000 cps when measured at 25 ° C and 20 rpm using a B-type rotational viscometer. Desirably within the range.

 The above emulsion preferably has a pH in the range of usually 2 to 10, especially 5 to 9, and the pH can be adjusted by using, for example, aqueous ammonia, aqueous ammonia, or aqueous aluminum hydroxide. it can.

The synthetic rubber-based emulsion polymer particles (A-1) used in the aqueous coating composition of the present invention have a Tg of 0 ° C or less, preferably 110 ° C or less, more preferably 120 ° C or less. Can be in the range of 80 ° C. A coating film formed from an aqueous coating composition prepared using synthetic rubber emulsion polymer particles having a Tg higher than 0 ° C. generally has low chipping resistance and is not so preferred. In this specification, the glass transition temperature (Tg) of the polymer particles is a value measured by the following method.

Glass transition temperature (T g):

 Approximately 1 Omg of (co) polymer emulsion sample is weighed into a cylindrical cell made of aluminum foil with a thickness of about 0.05mm, inner diameter of about 5mm and depth of about 5mm, and dried at 100 ° C for 2 hours The measured sample was used as the measurement sample, and the differential scanning calorimeter ft [Differential Scanning Ca 1 orimeter: 33 (-5000 type) manufactured by Seiko Instruments Inc.

Measure the difference in specific heat capacity before and after the glass transition temperature of the sample at a heating rate of 10 ° C / min from 50 ° C, and determine Tg from the results.

 In addition, the synthetic rubber-based emulsion polymer particles (A-1) generally include:

It is desirable to have a gel fraction in the range of 60-98% by weight, especially 70-95% by weight.

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

Gel fraction:

A film is prepared from the synthetic rubber-based polymer emulsion by drying at room temperature, and the film is put into about 200 to 800-fold toluene, left for 48 hours, and then filtered using No. 2 filter paper. The filtrate was dried under reduced pressure at 70 ° C and weighed to determine the toluene-soluble matter (% by weight) of the film from the polymer emulsion, and the value obtained by subtracting the toluene-soluble matter (% by weight) from 100%, ie, toluene The gel fraction is defined as the insoluble content (% by weight). Further, the average particle size of the synthetic rubber-based polymer particles (A-1) dispersed in the emulsion produced as described above (hereinafter simply referred to as the particle size) Is generally in the range of 0.05 to 0.5 micron, especially 0.1 to 0.3 micron. The particle size of the polymer particles in the emulsion can be controlled by, for example, appropriately selecting the type and amount of the surfactant to be used and the polymerization temperature. In the present specification, the average particle size of the polymer particles is described in “New Experimental Chemistry Course 4 Basic Technology 3 Hikari (Π)” edited by The Chemical Society of Japan, pages 725 to 741 (July 20, 1976, Maruzen Co., Ltd. This is a value measured by the DLS method described in (Issue), specifically, a value determined by the method described below.

Average particle size:

(Co) The polymer emulsion was diluted 50,000 to 150,000 times with distilled water, mixed well, and then collected in a 21 mm ø glass cell using a Pasteur pit to collect about 10 ml, which was then moved. manner light is set to a predetermined position of the scattering photometer DL S- 700 [manufactured by Otsuka Electronics (Ltd.)], _t measurement conditions measured by the following measuring conditions

 Measurement temperature 25 ± 1 ° C Clock rate (Clock Rete) 10〃 sec Correlation channel (Corel. Channel) 512

 Total number of measurement 200 times'

 Light scattering angle 90 °

The measurement results are processed by a computer to determine the average particle size.

As the synthetic rubber-based emulsion polymer particles (A-1), in addition to those produced by the above-mentioned method, for example, LX-407C [manufactured by Zeon Corporation], SN-318, SN-534, SN-562 , J-1666 [or more, Sumitomo Da 製 SK-80 [Made by Takeda Pharmaceutical Co., Ltd.], L-2001, L-2337 [Made by Asahi Kasei Kogyo Co., Ltd.], Polyrac 707 [Mitsui Toatsu Chemical Co., Ltd.] Styrene-butadiene-based synthetic rubber latex (hereinafter sometimes abbreviated as SBR) commercially available under trade names such as Nippon Nole 1571, Nipole 1551, Nipole 1562 [Nippon Zeon Co., Ltd. Acrylonitrile-butadiene-based synthetic rubber latex (hereinafter sometimes abbreviated as NBR) or the like, which is commercially available under a trade name such as NBR, can also be used.

High Tg emulsion polymer particles (A-2)

 In the aqueous coating composition of the present invention, the high Tg emulsion polymer particles (A-2) which can be used in combination with the above synthetic rubber emulsion polymer particles (A-1) as a vehicle component are: , Expression

Where:

R ¹ represents a hydrogen atom or a methyl group,

Q represents a Ariru group or one CN single COOR ^2, C ₆ ~ _12, wherein

R ² represents a lower alkyl group,

R ³ represents a hydrogen atom or a lower alkyl group,

Is contained in a proportion of 30 to 99.9% by weight, preferably 35 to 98.5% by weight, more preferably 40 to 96% by weight, based on the weight of the polymer. And a copolymer which can contain one or more kinds of other monomer units. Here, the term “lower” means that the group or compound to which this term is attached has 6 or less, preferably 4 or less carbon atoms.

Suitable as such another monomer unit is a repeating unit derived from a carboxy group-containing ethylenic monomer described below, and the copolymer preferably contains such a unit in an amount of 0.1 to 10% by weight. %, More preferably 0.5 to 5% by weight. Further, the copolymer may preferably contain 1 to 20% by weight, particularly 3 to 15% by weight of a repeating unit derived from a hydroxyl group-containing ethylene monomer described below.

 Such (co) polymers are, for example,

 (b-1)

R ¹

CH ₂ = CQ (Π)

Wherein R ¹ and Q are as defined above,

An ethylene monomer represented by the formula: wherein the homopolymer of the monomer is hydrophobic and has a Tg of 40 ° C or higher;

 (b-2) a carboxyl group-containing ethylenic monomer, preferably

 (b-3) Hydroxyl-containing ethylene monomer

And further as needed

 (b-4) Other copolymerizable monomers

Together with the emulsion polymerization.

Examples of the monomer (b-1) include C ぃ₄ alkyl esters of methacrylic acid such as methyl methacrylate, ethyl methacrylate, and iso-butyl methacrylate; styrene, α-methylstyrene, and vinyl. Aromatic vinyl compounds such as toluene and ethylvinylbenzene; (meth) Acrylonitrile; and the like. Among these, methyl methacrylate, is0-butyl methacrylate, styrene and acrylonitrile are preferred as the monomer (b-1) from the viewpoints of availability, ease of emulsion polymerization, and the like. is there. These monomers can be used alone or in combination of two or more.

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

Further, the hydroxyl group-containing ethylenic monomer (b-3) includes an α, -ethylenically unsaturated monomer containing 1 to 4, preferably 1 hydroxyl group in one molecule. , for example, can be exemplified 2- arsenide Dorokishechiru (meth) Akurireto, 2-hydroxycarboxylic propyl (meth) Akurireto such as a (meth) C ₂ ~ ₄ hydroxycarboxylic alkyl esters of Akuriru acid.

Further, other copolymerizable monomers (b-4) that can be used as necessary include, in the production of the synthetic rubber-based copolymer, "other copolymerizable monomers (a- 4) In addition to the monomers ① and ② mentioned above, ③ d ~ for vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate (trade name), etc. _2- saturated fatty acid vinyl monomer; monoolefin monomer such as ethylene, propylene, n-butylene, i-butylene; conjugated diolefin monomer such as butadiene, isoprene, chloroprene; dibutyl maleate, dioctyl maleate , dibutyl fumarate, Jiokuchirufumare one preparative, dibutyl itaconate, C ₄ ~ ₅ unsaturated and di O lipped itaconate a, y-dicarboxylic acid di-alkyl ester monomer; and the like can also be used. The monomers described above can be used alone or in combination of two or more. These monomers can be appropriately selected according to the physical properties desired for the polymer to be formed, for example, Tg. Among them, vinyl acetate, vinyl versatate (trade name) and butadiene are preferred. The monomers (b-1) to (b-4) described above are prepared by the same emulsion polymerization method as that described above for the production of the synthetic rubber-based latex polymer particles (A-1) [usually, atmospheric pressure. Emulsion polymerization under the following conditions].

 In the aqueous 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 synthetic rubber emulsion polymer particles (A-1) described above. A material having a Tg of at least 20 ° C is used. The glass transition temperature (Tg) required for the polymer particles (A-2) is desirably adjusted according to the baking temperature of the coating film formed from the final coating composition. For coating compositions for low temperature baking at about 60 to about 100 ° C, the Tg of the polymer particles (A-2) used is from 20 ° C to less than 60 ° C, preferably from 30 ° C to 55 ° C On the other hand, in the case of a coating composition for high-temperature baking at a baking temperature of about 120 to about 160 ° C., the polymer particles (A-2) of Tg is generally desired to be 60 ° C or higher, particularly 70 ° C or higher, and more preferably 85 ° C or higher.

The monomers (b-1) to (b-4) for producing the high Tg polymer particles (A-2) are selected from the group consisting of: Can be selected for emulsion polymerization. Use of these monomers As a general range of the use ratio, the following ranges can be exemplified. Monomer (b-1): 30-99.9% by weight Monomer (b-2): 0.1-10% by weight Monomer (b-3): 0-30% by weight Monomer (b-4) : 0-70% by weight Note: The% by weight is a percentage based on the total amount of monomers. The preferred proportion of each monomer component depends on the application (for low or high temperature baking) of the aqueous coating composition to which the high Tg polymer particles (A-2) to be formed are blended. You can choose from the following range: (1) In the case of high Tg polymer particles (A-2) used in the aqueous coating composition for low-temperature baking: a preferred range more preferred range

 Monomer (% by weight) (% by weight)

 (b-1) 35-80 40-75

 (b-2) 0.5 to 5:! ~ Four

 (b-3) 1-20 3〜15

 (b-4) 15-63.5 20〜55

 (2) For the high Tg polymer particles (A-2) used in the aqueous coating composition for high temperature baking:

 Preferred range More preferred range

 Monomer (% by weight) (% by weight)

 (b-1) 45-98.5 60-96

 (b-2) 0.5 ~ 5 '^ 4

 (b-3):! ~ 20 3 ~ 15

(b-4) 0-30 0-25 The copolymer emulsion formed by emulsion polymerization of these monomers (b-1) to (b-4) has high Tg polymer particles as a solid content.

 (A-2) can be contained in an amount of generally 10 to 70% by weight, preferably 30 to 65% by weight, and more preferably 40 to 60% by weight. Conveniently, the viscosity, measured at 25 ° C. and 20 rpm, is usually below 10,000 cps, in particular in the range from about 10 to about 5000 cps.

 The above emulsion preferably has a pH in the range of usually 2 to 10, particularly 5 to 9, and the pH can be adjusted using, for example, aqueous ammonia, aqueous ammonia, or aqueous aluminum hydroxide. it can.

 In general, it is desirable that the high Tg emulsion polymer particles (A-2) have a weight average molecular weight of 500,000 or more, especially 800,000 or more. The average particle size of the high Tg polymer particles (A-2) dispersed in the formed polymer emulsion is generally in the range of 0.05 to 0.511, particularly 0.1 to 0.3 // m. Preferably, the control of the particle size of the high Tg polymer particles (A-2) can be performed in the same manner as the control of the particle size of the synthetic rubber-based emulsion polymer particles (A-1).

Urethane emulsion polymer particles (A-3)

 The urethane-based emulsion polymer particles (A-3) that can be appropriately blended with the aqueous coating composition of the present invention include a urethane-based polymer emulsion known per se in the field of paints, adhesives, and the like. Can be used ο

Such a urethane polymer emulsion can be prepared by a conventional method by adding an isocyanate to a terminal obtained from a polyisocyanate compound and a polyol compound. It can be prepared by reacting a polyurethane prepolymer having a nate group with a chain extender and emulsifying it.

Examples of the polysocyanate compound that can be used in the production of the urethane-based emulsion polymer (A-3) include, for example, 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6 -Triylene diisocyanate, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 1 Aromatic polyisocyanate compounds such as 1,3-xylylene diisocyanate; 1.4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-1,6 Aliphatic polyisocyanate compounds such as -hexamethylene diisocyanate, 1,8-octamethylene diisocyanate, and 1,10-decamethylene diisocyanate; 1,3- or 1,4-cyclohexylenediene Isocyanate, 1- Tylcyclohexane-1,3- or 1,4-diisocyanate, 4,4'-dihexyl hexylmethane diisocyanate, isophorone diisocyanate, 1,3-isocyanomethylcyclohexane, etc. Aliphatic polyisocyanate compound; and the like. Among these polyisocyanate compounds, preferred are, for example, 2,4- or 2,6-tolylenediisocyanate, 1,4-tetramethylenediisocyanate, 1,6-hexamethylenediisocyanate, isophorone Diisocyanate. Examples of the polyol compound that can be reacted with the polyisocyanate compound include polyester polyols, polyether polyols, and polyester ether polyols. Examples of polyester polyols include ethylene glycol, propylene glycol, Polyhydric alcohols such as 1,4-butanediol, 1,6-hexanediol, glycerol, trimethylolpropane, pentaerythritol, sorbitan, sorbitol, and succinic acid, adipic acid, sebacic acid, maleic acid, Condensation with polycarboxylic acids such as fumaric acid, mesaconic acid, citraconic acid, icotanic acid, glutaric acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic acid and dodecanedicarboxylic acid And polylactone polymers.Examples of the above-mentioned polyether polyols include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyethylene propylene glycol. Can Examples of the polyester ether polyols include those obtained by adding an alkylene oxide such as ethylene oxide to the above polyester polyols, and a hydroxyl group at the terminal where the above polyether polyols and the above polycarboxylic acid are condensed. And the like.

As the chain extender, a compound having at least two functional groups containing an active hydrogen atom that reacts with an isocyanate group can be used. Typical examples thereof include water and polyhydric alcohols. And primary or secondary polyamines, hydrazine and derivatives thereof. The polyhydric alcohols include, for example, ethylene glycol, ethylene glycol, triethylene glycol, tetraethylene glycol, 1,2- or 1,3-propylene glycol, 1,2-, 1,3- or 1, Aliphatic diols such as 4-butylene glycol, 2,2-dimethyl-1,3-propylene glycol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol; 2, 2, 4, 4-tetramethylcyclobutane Alicyclic diols such as diol, 1,3-cyclopentanediol and methylenebis (4-cyclohexanol); 1,4-phenylenebis (2-hydroxyshethyl ether), 1,2-propylene glycol bis Aromatic diols such as (2-hydroxyphenyl ether); and the like. Examples of the polyvalent amines include ethylene diamine, hexamethylene diamine, isophorone diamine, diamino diphenyl methane, and ethylene triamine.Examples of the hydrazine derivative include dimethyl hydrazine and 1 Substituted hydrazines such as 1,6-hexamethylenebishydrazine; reaction products of dicarboxylic acids, disulfonic acids, lactones or polyhydric alcohols with hydrazine;

 Examples of the chain extender include, in addition to the above, those used to impart ionicity to urethane prepolymers and urethane-based resins when they are emulsified, and specific examples thereof include, for example, 2,2-dimethylolacetic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, and other dihydroxycarboxylic acids; 2,5-diaminobenzoic acid, α, £ Diaminocarboxylic acids such as -cabronic acid (lysine) and 2-amino-5-guanidinovaleric acid (arginine); alkyldialkanoylamines such as methyljetanoylamine; and the like.

The urethane prepolymer having an isocyanate group at the terminal is, for example, a mixture of the polyisocyanate compound and the polyol compound in a proportion such that the isocyanate group is in excess equivalent to the hydroxyl group under a nitrogen atmosphere. About 25-110 ° C with stirring in organic solvent In the presence of a catalyst according to the above. Examples of the organic solvent usable herein include: ketones such as acetone and methyl ethyl ketone; ethers such as dioxane and tetrahydrofuran; esters such as ethyl acetate; aliphatic hydrocarbons such as heptane and octane; Alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; and the like. Useful reaction catalysts include, for example, tertiary amines such as triethylamine; inorganic salts such as stannous chloride; and organic metal compounds such as di-n-butyltin dilaurate. The production of the urethane polymer emulsion from the urethane prepolymer prepared as described above and the chain extender can be carried out by various methods known per se.

 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 cationized with a quaternizing agent or an acid, or a chain extender Cationization by reacting a diol having a quaternary amino group as

(2) a method in which a polyurethane prepolymer having an isocyanate group at the terminal is polymerized using a polyalkylene polyamine as a chain extender, and then cationized by reacting an epihalohydrin with an acid;

And the like.

 Also, as a method for producing anionic emulsion, for example,

(3) A method in which a urethane prepolymer having an isocyanate group at the terminal is polymerized using dihydroxycarboxylic acid or diaminocarboxylic acid as a chain extender, and then neutralized with an alkaline compound to form an anion. Law,

 (4) a method of sulfonating a urethane prepolymer having an isocyanate group at the terminal obtained from a hydrophobic polyol and an aromatic polysocyanate to neutralize it with a tertiary amine to form an anion,

And the like.

 Further, as a method for producing a nonionic emulsion, for example,

 (5) A method in which a urethane prepolymer having an isocyanate group at a terminal is dispersed in an aqueous solution containing diamine or the like as necessary using an emulsifier, and the chain is extended with water or diamine.

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

 (7) a method of reacting the above-mentioned chain extender with a urethane prepolymer having an isocyanate group at a terminal to form a urethane resin, and mechanically dispersing the resin in water using an emulsifier;

And the like.

Examples of the urethane polymer emulsion that can be used in the present invention include, in addition to those described above, a urethane prepolymer which contains, for example, a hydroxyl-containing vinyl monomer such as 2-hydroxyshetyl acrylate. A mixture obtained by emulsifying and copolymerizing the urethane prepolymer and the (meth) acrylic monomer; a part of the isocyanate group of the urethane prepolymer having an isocyanate group at the terminal is replaced with various blocking agents Or by reacting the urethane prepolymer or the urethane-based polymer with one part of an isocyanate group ^ blocked urethane prepolymer. The urethane prepolymer or urethane-based polymer containing a blocked isocyanate and emulsified by the same method as described above can also be used.

 Among these, urethane-based emulsions include the stability of miscibility with the synthetic rubber-based emulsion polymer particles (A-1) and the high Tg emulsion polymer particles (A-2) described above, and the properties of the coating composition. It is preferable to use an anionic or nonionic emulsion from the viewpoints of easiness of preparation and storage stability of the final coating composition.

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

Further, the urethane-based emulsion polymer particles (A-3) are used in consideration of the degree of improvement in the prevention of blistering at the time of baking of a coating film formed using the final coating composition, the wet-resistant chipping resistance, and the like. The stress at the time of 100% elongation of the film formed from the urethane polymer emulsion containing the polymer particles (A-3) (hereinafter sometimes referred to as 100% modulus) and the yield before 100% elongation whichever is greater numeric value generally 20 kg / cm ² or more, preferably 30 k gZc m ² or more, it is desirable to further preferably in the range of 40~ 30 0 k cm ^2.

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

To determine the 100% modulus and yield value of a film:

Dry on a release paper fixed horizontally using a doctor blade. A urethane-based polymer emulsion is applied so as to have a value of β, dried at room temperature, and then heat-treated at 120 ° C. for 10 minutes in a hot-air circulating drier to form a urethane-based polymer film. After leaving the obtained film under a constant temperature and humidity condition of 23 ° C. and 65% RH for 3 hours or more, a stress-elongation curve is measured under the same condition, and a required 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 grip interval of 10 mm, and a tensile speed of 100 mm / min.

Aqueous coating composition:

 The aqueous coating composition of the present invention may contain, as a vehicle component, a synthetic rubber-based emulsion polymer particle (A-1) which is an essential component, or, if necessary, the polymer particle (A-1). Combination with high Tg emulsion polymer particles (A-2), or the combination of polymer particles (A-1), high Tg emulsion polymer particles (A-2) and urethane resin emulsion particles It can be prepared by blending an isocyanate derivative (C) as a crosslinking agent and an inorganic filler in combination with (A-13). The blending amounts of the above polymer emulsions (A-1) and (A-2) are based on the total amount of the polymer particles (A-1) and (A-2) (that is, the solid component) in these emulsions. Thus, the synthetic rubber-based emulsion polymer particles (A-1) have a weight ratio of 50 to 100% by weight, preferably 55 to 95% by weight, more preferably 60 to 90% by weight, and a high Tg emulsion polymerization. The body particles (A-2) can be in the range of 0 to 50% by weight, preferably 5 to 45% by weight, and more preferably 10 to 40% by weight.

In addition, the above-mentioned aqueous coating composition may contain, if necessary, the urethane described above. Resin-emulsion (A-3) can be blended, thereby improving the adhesion of the coating film formed from the coating composition to a wet-resistant chipping-resistant substrate, particularly to a cation electrodeposited steel sheet. Although it can be significantly improved, the compounding amount is as solid content, that is, as a urethane-based resin emulsion particle (A-13), a synthetic rubber-based emulsion polymer particle (A-1) and a high Tg emulsion polymer. It can be in the range of 3 to 100 parts by weight based on the total 100 parts by weight of the particles (A-2), and in the case of the aqueous coating composition for low temperature baking, it is 5 to 90 parts by weight. Parts by weight, particularly preferably in the range of 10 to 80 parts by weight.On the other hand, in the case of the aqueous coating composition for high temperature baking, it is 4 to 70 parts by weight, particularly 5 to 50 parts by weight. Is preferably within the range.

 Further, the aqueous coating composition of the present invention contains an isocyanate derivative (C) as a crosslinking agent. By adding the isocyanate derivative (C), adhesion of the coating film formed from the coating composition to a substrate, particularly a cationic electrodeposition coated steel sheet, under normal and wet conditions, and resistance to normal and wet conditions. It is possible to improve the chipping property and the blister limit of the coating film when baking at a high temperature.

 Examples of the isocyanate derivative (C) include an aziridine compound and a blocked isocyanate, and both are preferably water-dispersible compounds.

As the aziridine compound, a reaction product of a polyisocynate compound and ethylenimine can be used, and as the polyisocynate compound, those usable in the urethane-based resin emulsion particles (III-3), that is, aromatic compounds Aliphatic polyisocyanate compounds, aliphatic polyisocyanate compounds, and alicyclic polyisocyanate compounds. In addition, dimers or trimers of these isocyanates; adducts of these isocyanates with, for example, divalent or trivalent polyols such as ethylene glycol and trimethylolpropane can be exemplified.

 Among such aziridine compounds, commercially available water-dispersible aziridine compounds that can be suitably used in the present invention include, for example, SU-125F [manufactured by Meisei Chemical Industry Co., Ltd.] and DZ-22E. [Manufactured by Nippon Shokubai Co., Ltd.]. ·

 Examples of the blocked isocyanate include, for example, those obtained by adding a volatile low-molecular-weight active hydrogen compound to the polyisocyanate compound, such as trimethylol pulp pantolylene diisocyanate methylethylketoxime adduct. Examples of such volatile low molecular active hydrogen compounds include methyl alcohol, ethyl alcohol, n-butyl alcohol, cyclohexyl alcohol, benzyl alcohol, ethylene glycol monoethyl ether, and ethylene glycol mono. Aliphatic, alicyclic or aromatic alcohols such as butyl ether and phenol; tertiary hydroxylamines such as dimethylaminoethanol and getylaminoethanol; acetoxime, methylethylketoxim and the like Ketokishimu like; for example, Asechiruaseton, Aseto acetate S. ether, active methylene compounds such as malonic acid ester; .epsilon. force lactams such as Rorakutamu; etc. can be exemplified.

Among such blocked isocyanates, commercially available water-dispersible blocked isocyanates that can be suitably used in the present invention include, for example, DΜ-30, DM-60 [these are Meisei Chemical Co., Ltd. Elastron BN-69, Elastron BN-44, Elastron BN-08 [ Manufactured by Daiichi Kogyo Seiyaku Co., Ltd.].

 In the present invention, among these isocyanate derivatives (C), the temperature dependency of the cross-linking reaction is small, the size of the effect of improving the blister limit film thickness is increased, and the obtained coating film has wet-tipping resistance and substrate adhesion. It is preferable to use an aziridine compound from the viewpoint of the remarkable improvement effect such as the above.

 The compounding amount of the isocyanate derivative (C) is determined by the amount of the polymer fine particles (A) contained in the aqueous coating composition of the present invention (that is, the synthetic rubber-based emulsion polymer particles (A-1) as an essential component). And the total of high Tg emulsion polymer particles (A-2) and urethane-based resin emulsion particles (A-3) contained as necessary] of 0.1 parts by weight. To 10 parts by weight (solid content), preferably 0.3 to 7 parts by weight, particularly preferably 0.5 to 5 parts by weight.

 On the other hand, the aqueous medium used in the aqueous coating composition of the present invention is derived from the above-described emulsion, and is usually water. In some cases, water and a water-miscible organic solvent may be used. It may be a mixed solvent.

 Further, in the aqueous coating composition of the present invention, the inorganic filler (B) is blended with the composition for the purpose of, for example, an extender, adjustment of the hardness of the coating film, prevention of blister generation, and the like.

 The aqueous coating composition of the present invention preferably contains at least white carbon (B-1) as such an inorganic filler (B). By containing the white carbon (B-1), the chipping resistance at normal temperature and wetness, and the blister limit of the film when baking at high temperature can be further improved.

As the white carbon (B-1) which can be used in the present invention, For example, fine powders of gay acid anhydride by dry method, hydrous acid acid by synthetic method, synthetic gay acid salt, and fine particles of high-purity gay anhydride are dispersed in water to form a colloid. (Hereinafter, sometimes referred to as colloidal silica).

 The above-mentioned dry method is defined as: (1) thermal decomposition of halogenated gay acid;

(2) Air-oxidation of vaporized Si0 by heating and reducing ky sand; (3) Thermal decomposition of organic gay compound;

 The hydrous maleic acid obtained by the wet method is as follows: (1) thermal decomposition of sodium silicate; (2) thermal decomposition of alkaline earth metal silicate; (3) pressure decomposition of organogel; (4) auxiliary lime during the production of lime fertilizer. Organism: etc.

 The above-mentioned synthetic gayates are: (1) the reaction of sodium silicate with a soluble salt of aluminum or calcium; (2) the reaction of natural gay acid or gaylate with hydroxide of alkaline earth metal. Products made by manufacturing methods such as thermal reaction.

These white Tokabon generally, the average particle size 200 ^ or less (secondary particles child), an ultra fine bulky white powder over the surface area 10 m ² Zg, as dry-type method anhydride Gay acids, for example, Leo port seal GS 13 , Leo mouth seal QS102, Leo mouth seal QS30, Leo mouth seal QS38 (or more, manufactured by Tokuyama Soda Co., Ltd.), Aerozil 130, Aerozil 200, Aerozil 300, Aerozil 380, Aerozil 0X50, Aerozil TT 600, AEROSIL MOX80, AEROSIL MOX170, AEROSIL COΧ84, AEROSIL R 972, AEROSIL R 974 (above, manufactured by Nippon AEROSIL Co., Ltd.); As wet-process hydrous gay acid, for example, Starcil-S (manufactured by Kamishima Chemical Industries, Ltd.), Carplex # 67, Carplex # 80, Carplex # 1120, Carplex # 100, Carplez CX XR, Carplex 22S, Carplex CS-5, Carplex CS-7, Carplex CS-701 (above, Shionogi Pharmaceutical Co., Ltd.), Toxir U, Carplex UR, Carplex Gu, Rikiichiplex AL — 1, Carplex US (from Tokuyama Soda Co., Ltd.), Nip Seal VN3, Nip Seal AQ, Nip Seal LP, Nip Seal — ER, Nip Seal NS, Nip Seal NS—P, Nip Seal NS—T, Nip Seal NS—K, Nip seal ΝΑ, Nip seal L 300, Nip seal Ν 300 Α, Nip seal Κ 300, Nip seal G 300, Nip seal Ε 150 Κ, Nip seal Ε 150】, Nip seal Ε 200, Nip seal Ε 220, Nip seal Ε 220 Α Co., Ltd.), Shilton R-2, Shilton A Manufactured by Sawa Chemical Industry Co., Ltd.]; as synthetic gay salts, for example, Starlex L [manufactured by Kamishima Chemical Industry Co., Ltd.], Silmos T [manufactured by Shiraishi Industry Co., Ltd.], Solexex CM, Flow Light R Examples thereof include those commercially available under trade names such as [manufactured by Tokuyama Soda Co., Ltd.], Mistron Vapor, and Cybra Bond [manufactured by Nippon Mistron Co., Ltd.].

 Examples of the colloidal silica include Snowtex 20, Snowtex 30 (manufactured by Nissan Chemical Industries, Ltd.), Adelaide AT-30, Adelaite AT-50 [manufactured by Asahi Denka Kogyo Co., Ltd. ] And the like, which are commercially available.

The amount of the white carbon (B-1) is preferably 0.5 to 100 parts by weight, more preferably 1 to 80 parts by weight, and still more preferably 100 parts by weight of the polymer fine particles (A) in total. An example of the amount is about 2 to 60 parts by weight. When the amount of the white carbon (B-1) is greater than or equal to the lower limit, When the obtained aqueous coating composition is used as an aqueous coating composition for chipping resistance, the blister limit film thickness and the chipping resistance are improved, which is preferable. On the other hand, when the content is equal to or less than the upper limit, the obtained film retains flexibility and elasticity, and good chipping resistance can be maintained.

 The aqueous coating composition of the present invention further comprises an inorganic filler (B-2) other than the white carbon (B-1) as the inorganic filler, in addition to the white carbon (B-1). ), For example, heavy calcium carbonate, light calcium carbonate, silica other than the above-mentioned white carbon, alumina, kaolin, clay, talc, diatomaceous earth, my strength, aluminum hydroxide, glass powder, barium sulfate, magnesium carbonate, etc. Can be contained.

 The amount of the inorganic filler (B-2) other than white carbon can be varied in a wide range depending on the kind and physical properties desired for the coating composition. In general, 100 to 560 parts by weight, preferably 120 to 390 parts by weight, more preferably 150 to 3 parts by weight, based on a total of 100 parts by weight of the obtained polymer fine particles (A). It can be in the range of 100 parts by weight.

 In addition, it is desirable that the inorganic filler (B-2) has an average particle size of generally about 0.5 to about 50 // m, particularly 1 to about 30 m. .

 The coating composition of the present invention may contain, if necessary, a crosslinking agent other than the anti-pigment pigment (E), the color pigment, and the isocyanate derivative (C), as in the ordinary coating composition. can do.

Examples of the above-mentioned anti-pigment pigment (E) include: lead tin; metal chromate salts such as zinc chromate, barium chromate, and strontium chromate; Lead, calcium phosphate, aluminum phosphate, titanium phosphate, silicon phosphate, or a metal phosphate such as ortho or condensed phosphate of these metals; zinc molybdate, calcium molybdate, calcium zinc molybdate; Metal molybdates such as potassium zinc molybdate, zinc phosphate molybdate, calcium potassium phosphomolybdate; metal borate salts such as calcium borate, zinc borate, barium borate, barium metaborate, calcium metaborate; Examples can be given. Among these pigments, non-toxic or low-toxic pigments such as metal phosphates, metal molybdates and metal borates are preferred.

 The blending amount of the water-proof pigment (E) is, for example, 0 to 50 parts by weight, preferably 5 to 30 parts by weight with respect to 100 parts by weight of the polymer fine particles (A) in the coating composition. Can be exemplified.

 Examples of the coloring pigment include, for example, organic or inorganic coloring pigments such as titanium oxide, carbon black, red iron oxide, Hansa Yellow, benzidine yellow, phthalocyanine yellow, and quinacridone red. The compounding amount of these coloring pigments is determined based on the amount of the polymer fine particles in the coating composition.

The amount can be, for example, in the range of 0 to 10 parts by weight, preferably 0.5 to 5 parts by weight with respect to 100 parts by weight.

 In addition, the particle diameter of the anti-sun pigment and the color pigment is preferably in the range of 1 to 50 zm from the viewpoint of the smoothness of the formed film of the obtained coating composition.

 In the composition of the present invention, an appropriate crosslinking agent other than the isocyanate derivative (C) can be further compounded, if necessary.

Crosslinking agents other than such isocyanate derivatives include: (a) Zinc salts such as zinc acetate, zinc formate, zinc sulfate, zinc chloride; aluminum salts such as aluminum acetate, aluminum nitrate, aluminum sulfate; calcium acetate, calcium iodate, calcium chloride, calcium nitrate, sulfurous acid Calcium salts such as calcium: barium salts such as barium acetate, barium chloride, barium sulfite: magnesium salts such as magnesium acetate, magnesium formate, magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium sulfite; lead acetate, lead formate, etc. Lead salts of Niger, Niger acetate, Niger chloride, Niger nitrate, Niger sulfate, etc .; Nigel salts such as manganese acetate, manganese chloride, manganese sulfate, manganese nitrate, etc .; Copper salts such as copper nitrate and copper sulfate; (B) water-soluble epoxy resin, for example, glycerol diglycidyl ether; (C) water-soluble melamine resin, for example, methylol melamine; at least a part of the hydroxyl group of the methylol melamine is methyl alcohol. And those etherified with ethyl alcohol, n-butyl alcohol, and the like.

 The amount of the crosslinking agent used is, for example, 0 to 10 parts by weight based on 100 parts by weight of the polymer fine particles in the composition, from the viewpoint of suppressing the change over time of the viscosity of the obtained coating composition. Parts, preferably 0.5 to 10, particularly preferably 1 to 5 parts by weight.

 The aqueous coating composition of the present invention can further contain, if necessary, heat-expandable polymer beads and Z or hollow beads (D).

In general, fibrous or modified inorganic fillers such as light calcium carbonate and modified calcium carbonate are added to aqueous coating compositions for the purpose of further improving swelling prevention, chipping resistance, low-temperature impact resistance, etc. if you did this, There is a problem that cracks are easily formed in the coating due to rapid drying shrinkage during heating and drying. However, by adding the above-mentioned heat-expandable polymer beads and / or hollow beads (D), the coating for aqueous coating can be obtained. While maintaining the excellent properties of the composition, it is possible to prevent the occurrence of cracks in the coating, and at the same time to obtain an excellent aqueous coating composition that also has the effect of reducing the weight of the coating. .

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

 The thermoplastic resin is not particularly limited as long as it is softened at a heating temperature when forming a coating film using the obtained coating composition, and is, for example, 60 to 130 °. It is preferable to use a resin which softens at C, especially about 70 to 120 ° C., for example, polyolefin, polyacrylonitrile, polyacrylate, polystyrene, polyvinyl chloride, polyvinylidene chloride, and the like. Thermoplastic resins such as vinyl resins such as these copolymers; polyester resins; silicone resins; thermoplastic urethane resins;

 As the heat-evaporating foaming agent, for example, organic solvents such as hydrocarbons, halogenated hydrocarbons, esters, ethers, and ketones having a low boiling point of about 150 to 150 ° C can be used. ,

Examples of the heat-decomposable foaming agent include N, Ν'-dinitrosopene methylenetetramamine, Ν, N'-dimethyl-Ν, Ν'-dinitrosotere phthalamide and other nitroso compounds such as azodicarbonamide. Compounds such as benzenesulfonyl hydrazide, Ρ, ' Sulfonyl hydrazide compounds such as cis (benzenesulfonylamide), benzene-1,3-disulfonyl hydrazide, toluenesulfonyl hydrazide and derivatives thereof; p-toluenesulfonyl semicarbazide; trihydrazino triazine; it can.

 The thermal expansion temperature of these heat-expandable polymer beads is, for example, about 60 to: L80 ° C, particularly about 70 to: L60 ° C. Excellent stability before and after thermal expansion, excellent safety, easy to obtain, good.Vinyl resin such as acrylonitrile vinylidene monochloride copolymer is used as shell wall, and hydrocarbon organic solvent such as isobutane is heated and vaporized. Those encapsulated as a mold blowing agent are particularly preferred.

 Further, the thermal expandable polymer beads have an average particle diameter before thermal expansion of 1 to 50 m, particularly about 3 to 40 m, and an average particle diameter after thermal expansion of 5 to 3 m. It is preferably about 100 / zm, particularly about 20 to 200 zm.

 Examples of the heat-expandable polymer beads that can be suitably used in the present invention include, for example, Matsumoto Microsphere F-30 and Matsumoto Microsphere F-50. Expansel WU * 642, Expansel WU-551. Manufactured by Nippon Fillite Co., Ltd.].

Some of these thermally expandable polymer beads are commercially available as a so-called “jet cake” containing water for reasons such as easy handling. The above-mentioned Matsumoto Microsphere F- 3 0, Matsumoto Mai Crossfer F—50, Expancel WU * 642, Expancel WU * 551, Expancel WU * 461, etc. are of this type. The hollow beads that can be used in the present invention include hollow polymer beads and hollow inorganic beads.

 As the hollow polymer beads, for example, polyolefin, polyacrylonitrile, polyacrylate, polystyrene, polyvinyl chloride, polyvinylidene chloride, and copolymers thereof as in the case of the heat-expandable polymer beads: polyester resin; silicone resin; Thermoplastic resin such as thermoplastic polyurethane resin; and the like having a shell wall can be used. For example, it is preferable to use the thermally expandable polymer beads which have been thermally expanded in advance under appropriate heating conditions. Can be. In addition to these, those using a thermosetting resin such as an amino resin, a fuanol resin, or an unsaturated polyester resin as a shell wall can also be used.

 The average particle size of such hollow polymer beads is generally 1 to 5005m, preferably about 5 to 300; / m.

 Hollow polymer beads that can be suitably used in the present invention are commercially available, for example, under the trade names such as Expanscel DE * 551, Expanscel WE * 551 (hereinafter, manufactured by Nippon Philite Co., Ltd.). Can be listed. As in the case of the above-mentioned swellable polymer beads, these hollow polymer beads are commercially available as a so-called “ゥ et cake” containing water for reasons such as easy handling. Kupancel WE * 5 5 1 is of this type.

The hollow inorganic beads that can be used in the present invention include inorganic substances such as glass, silica, shirasu, carbon, alumina, and zirconia. A wall is preferably used.

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

 Examples of the hollow inorganic beads that can be suitably used in the present invention include, for example, Q-CEL200, Q-CEL300, QCEL600 (all manufactured by Asahi Glass Co., Ltd.), Scotchlite B28Z750, Scotchlite B38 / 4000 and Scotch Light B46 / 4000 (above, manufactured by Sumitomo SLIM Co., Ltd.). These heat-expandable polymer beads and hollow beads can be appropriately used in combination.

 The amount of the heat-expandable polymer beads and / or hollow beads (D) 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) in total. 0.3 to 35 parts by weight, particularly preferably 0.5 to 30 parts by weight. When the amount is equal to or more than the lower limit, cracking of the obtained coating film can be prevented, and when the amount is equal to or less than the upper limit, the obtained coating film is smooth and the film has an anti-chipping property. Is not preferred.

The aqueous coating composition of the present invention may further include, if necessary, an inorganic dispersant [eg, sodium hexamethacrylate, sodium tripolyphosphate, etc.], an organic dispersant [eg, Nobu Cospers 44C (trade name) Dispersants, such as silicone-based defoamers; silicone-based defoamers; polyvinyl alcohol, cellulose derivatives, polycarboxylic acid-based resins, and surfactant-based thickeners. And viscosity improvers: ethylene glycol, butyl sorbitol, butyl carbitol, butyl carbitol acetate And an anti-aging agent; an antiseptic and a fungicide; an ultraviolet absorber; an antistatic agent; and the like.

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

 The substrate to which the aqueous coating composition of the present invention can be applied is not particularly limited. For example, a steel plate; for example, a lead-tin alloy plated steel plate (tan sheet steel plate), a tin plated steel plate, an aluminum plated plate Various plated steel plates such as steel plate, lead plated steel plate, chrome plated steel plate and nickel plated steel plate; painted steel plate such as electrodeposited coated steel plate; and the like.

 Particularly, the coating composition of the present invention is obtained by molding such a base material into various shapes by a sheet metal press or the like and by welding them as various automobile members, for example, a gasoline tank of an automobile, an under floor, It can be suitably used for coating an electrodeposition-coated surface, a middle-coated surface, or a top-coated surface of a sheet metal processing member outside a vehicle compartment such as a tire house, a front apron, and a rear apron.

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

The coating thickness at that time varies depending on the application of the base material, etc. A range of 0 to about 800 / m, especially about 300 to about 600 m, is suitable. The coating film can be dried by natural drying, heating drying, etc., but generally, in the case of an aqueous coating composition for low-temperature baking, a heating oven at a temperature of about 60 to about 100 ° C is used. In the case of an aqueous coating composition for high-temperature baking, after pre-drying at a temperature of about 60 to about 100 ° C, a heating furnace having a temperature of about 120 to about 160 ° C is preferable. It is convenient to bake in o

 Hereinafter, the present invention will be described more specifically with reference to examples.

 BEST MODE FOR CARRYING OUT THE INVENTION

 The preparation of test samples used in the examples and comparative examples and the test method are as follows.

 (1) Preparation of test piece

 Each sample was airless blown onto a 0.8x100x200mm thick automotive steel plate (hereinafter sometimes referred to as an ED plate), which was electrodeposited using a cationic electrodeposition paint “U-600” manufactured by Nippon Paint Co., Ltd. The dried coating film is applied to a specified thickness by the varnish coating method, and is heat-treated under specified conditions using a hot air circulation type dryer.

 (2) Limit thickness of blister or crack

 In the spray coating in the preceding paragraph (1), apply the paint by changing the thickness of the dried coating film, find the maximum film thickness that does not cause blisters or cracks when drying, and use it as the blister limit film thickness or crack limit film thickness .

 (3) Adhesion test

In the preceding (1), the test piece obtained by painting so that the dry film thickness is about 300 / m was painted using a Goban eye tester [manufactured by Suga Test Machine Co., Ltd.]. Vertical from the surface, is entering the depth of the cutlet preparative lines reaching to the substrate in the horizontal respectively lmm intervals to create a 100 squares in 1 cm ^2. A 24-mm cellophane tape [manufactured by Nichiban Co., Ltd.] was applied to the goban, and it was immediately peeled off by 180 ° by hand. The number of eyes remaining on the paint film was counted, and the remaining paint film number was 100. indicate.

 (4) Anti-chipping resistance test

In the previous section (1), a test piece obtained by coating to a dry film thickness of about 300 zm was left at a constant temperature of about 25 ° C for 16 hours. Create 100 squares in 4 cm ² at ² mm intervals in the vertical and horizontal directions at the depth from the coating surface to the base material.

 The test specimen was fixed upright at an angle of 60 ° to the horizontal plane, and a nut (M-6) was placed on the painted surface vertically from a height of 2 m using a 25 mm ø PVC pipe. Drop it continuously toward the center and evaluate the total weight of the dropped nuts when the substrate of the ED board is exposed.

 (5) Wet chipping resistance test

 In the previous section (1), a test piece obtained by coating to a dry film thickness of about 300 was immersed in deionized water at about 40 ° C for 7 hours, taken out, wiped off the moisture, and then ) Create a Goban eye in the same way as in Section 25. After leaving at C for 3 hours, a chipping resistance test is performed in the same manner as in (4) above, and the same evaluation is performed.

 (6) Low temperature impact resistance test

In the previous section (1), the test specimen was left under a constant temperature condition of -30 ° C for 3 hours or more, and then at the same temperature, a DuPont impact tester was applied in accordance with JISK-5400. Perform a strike.

 The conditions at this time were as follows: a shooting die with a radius of 6.35 ± 0.33 mm and a cradle were attached to the tester, and the test piece was sandwiched between them with the coating surface facing upward. Drop from a height of cm onto the shooting mold and visually evaluate the degree of damage to the coating surface according to the following evaluation criteria.

 ◎ No change

 微 Slight cracking

 Δ Many fine cracks occur

 X Large crack occurrence

Reference example 1

 A 2000 ml separable flask having 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) are placed in a separate container and stirred to form a uniform aqueous solution, and 485 parts by weight of styrene (St) and acryl A monomer mixture obtained by uniformly mixing 15 parts by weight of an acid (AA) is added dropwise and stirred to form a monomer pre-emulsion. The pre-emulsion and an aqueous solution of a polymerization initiator are prepared by adding ammonium persulfate (APS) 5 A 30% by weight aqueous solution was continuously added over 3 hours, then kept at the same temperature for 1 hour, and 4 ml of about 25% by weight aqueous ammonia was added to obtain a styrene copolymer emulsion.

The polymer monomer composition during, solid content of the obtained copolymer Emarujon, pH, viscosity, particle size, and show the T _g of the copolymer particles in Table 1. Reference example 2 In Example 1, use 485 parts by weight of St. Instead of using 435 parts by weight of St and 50 parts by weight of 2-hydroxyshethyl methacrylate (HEMA), use the styrene-based A copolymer emulsion was obtained. Table 1 shows the monomer composition, the solid content, the pH, the viscosity, the particle size, and the Tg of the obtained copolymer emulsion at the time of this polymerization.

Reference example 3

 An acryl-based resin was prepared in the same manner as in Reference Example 1 except that 335 parts by weight of methyl methacrylate (MMA) and 150 parts by weight of acrylonitrile (AN) were used instead of using 485 parts by weight of St. A copolymer emulsion was obtained. Table 1 shows the monomer composition, the solid content, the pH, the viscosity, the particle size, and the Tg of the obtained copolymer emulsion in this polymerization.

Reference example 4

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

Reference example 5

In Reference Example 4, styrene was used in the same manner as Reference Example 4 except that St 320 parts by weight, EHA 115 parts by weight and HEMA 50 parts by weight were used instead of St 360 parts by weight and EHA 125 parts by weight. Acryl A polymer emulsion was obtained. Table 1 shows the monomer composition, the solid content, the pH, the viscosity, the particle size, and the Tg of the copolymer particles in this polymerization.

Reference example 6

An acrylic copolymer emulsion was obtained in the same manner as in Reference Example 4, except that 335% by weight of MMA and 150 parts by weight of EHA were used instead of 360 parts by weight of St and 125 parts by weight of EHA. . Table 1 shows the monomer composition, the solid content, the pH, the viscosity, the particle size, and the Tg of the copolymer particles obtained in the polymerization.

Table 1 Item Monomer composition (% by weight) Copolymer emulsion characteristics Copolymerization

 (b-1) (b-2) (b-3) (b-4) Solid content P H viscosity particle size Tg. St MMA ANAA HEMA EHA (Weight 6) (cps) (μ) (° C) Reference 1 97 3 50 7.5 120 0.2 93 Reference 2 87 ', 10 650 90 Reference 3 67 30 0 180 105 Reference 4 72 25 210 50 Reference example 5 64 10 23 960 0

Reference example 6 67

Example 1

 Commercially available SBR polymer emulsion-SN-562 [manufactured by Sumitomo Dow Co., Ltd .: Tg-40 ° C, viscosity 170 cps, pH 7.1, solid content 52.5 wt%, particle size 0.16 /] 133 Parts by weight (about 70 parts by weight of solid content), 60 parts by weight of styrene copolymer emuldione of Reference Example 1 (about 30 parts by weight of solid content), and an aziridine compound SU-125F as an isocyanate derivative of a crosslinking agent. [Manufactured by Meisei Chemical Industry Co., Ltd.] 4.0 parts by weight (solid content: about 1.0 part by weight), Nobucosper 44C as a dispersant [manufactured by San Nopco Co., Ltd., polycarboxylic acid type] 2.0 parts by weight ( (Solid content: about 0.88 parts by weight), powdered heavy calcium carbonate SL-700 (average particle size: 4.5, manufactured by Takehara Chemical Industry Co., Ltd.) as an inorganic filler 218 parts by weight, carbon black: 3 parts by weight, and metaboric acid Disperse 12 parts by weight of barium evenly using a tasper, then use a thickener Add 0.5 parts by weight of Adekinol UH-472 (manufactured by Asahi Denka Co., Ltd.) and further stir to obtain the total pigment (powder heavy calcium carbonate, carbon black and barium metaborate) in the coating film. (Total amount) (hereinafter sometimes abbreviated as PWC) at 70% by weight and a solid content of 77.5% by weight. Various physical property tests were performed using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 3 (1). The coating film was subjected to high-temperature baking (preliminary drying at 80 ° C for 15 minutes and baking at 130 ° C for 20 minutes) using a hot-air circulation dryer.

Comparative Example 1

In Example 1, the aziridine compound SU-125F was not used. Except for this, the same procedure as in Example 1 was carried out to prepare a composition for a water-resistant chipping-resistant coating having a PWC of 70% by weight.

 Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 1 (1).

Example 2

 In Example 1, instead of using 218 parts by weight of powdered heavy calcium carbonate SL-700, 198 parts by weight of powdered heavy calcium carbonate SL-700 and Nipsil E-200A as white carbon [Nihon Siri Riki Kogyo Co., Ltd. Production of a chipping resistant aqueous coating composition having a PWC of 70% by weight was performed in the same manner as in Example 1 except that 20 parts by weight was used.

 Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 1 (1).

Example 3

 In Example 1, instead of using 218 parts by weight of powdered heavy calcium carbonate S L-700, instead of powdered heavy calcium carbonate S L-700 116 parts by weight and light calcium carbonate [manufactured by Maruo Calcium Co., Ltd .;

, A minor axis of about 0.4 zm], 100 parts by weight, and furthermore, Matsumoto Microsphere F-50 (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd .; moisture content: about 30% by weight; particles before thermal expansion) as heat-expandable polymer beads. Diameter 10-20 zm; particle diameter after thermal expansion 30-80 m: softening temperature of shell wall 100-105 ° C] 2 parts by weight (approx. 1.4 parts by weight, excluding water, but a heating-vaporizing foaming agent) In the same manner as in Example 1 except that A water-based coating composition having a chipping resistance of 70% by weight of PWC was prepared. Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 1 (1).

Example 4

 In Example 1, instead of using 218 parts by weight of powdered heavy calcium carbonate SL-700, 113 parts by weight of powdered heavy calcium carbonate SL-700 and 100 parts by weight of light calcium carbonate were used, and Scotch lime was used as a glass bead. G B38 / 4000 [manufactured by Sumitomo 3LEM Co., Ltd .; average particle density 0.38 g / cc] In the same manner as in Example 1 except that 5 parts by weight is blended, a composition for a water-resistant coating with 70% by weight of PWC is prepared. Things were created.

 Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 1 (1).

Examples 5 to 6

 In Example 2, PWC was 70% by weight in substantially the same manner as in Example 2, except that the copolymer emulsions of Reference Examples 2 to 3 were used instead of using the styrene copolymer emulsion of Reference Example 1. % Of an anti-chubbing aqueous coating composition.

 Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 1 (1).

Examples 7 to 8 In Example 3, PWC was 70% by weight in substantially the same manner as in Example 3, except that the copolymer emulsions of Reference Examples 2 to 3 were used instead of using the styrene copolymer emulsion of Reference Example 1. A composition for water-based coating with anti-chipping properties was prepared.

 Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 1 (1).

Example 9

 In Example 2, instead of using 133 parts by weight of SBR-based polymer emulsion SN-562 (about 70 parts by weight of solid content), Nipole 1551, a commercially available NBR-based polymer emulsion [Nippon Zeon Co., Ltd .: Tg — 39 ° C, viscosity 50 cps, pH 9.5, solid content 51% by weight, particle size 0.18] Except for using 137 parts by weight (about 70 parts by weight in solid content), A composition for an aqueous coating with anti-chipping properties with a PWC of 70% by weight was prepared.

 Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 1 (1).

Example 10

In Example 3, instead of using 133 parts by weight of SBR-based polymer emulsion SN-562 (about 70 parts by weight of solid content), 137 parts by weight of Nipol 1551 of NBR-based polymer emulsion (about 70 parts by weight of solid content) was used. (Parts by weight) A chipping-resistant aqueous coating composition having a PWC of 70% by weight was prepared in substantially the same manner as in Example 3 except that the composition was used. Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 1 (1).

Example 11

 In Example 1, 3 parts by weight of SBR polymer emulsion-SN-562 133 (about 70 parts by weight in solid content) and 60 parts by weight of styrene copolymer emulsion in Reference Example 1 (about 30 parts by weight in solid content) ), 114 parts by weight of SBR-based polymer emulsion SN-562 (about 60 parts by weight in solid content), 60 parts by weight of styrene-based copolymer emulsion in Reference Example 1 (about 30 parts by weight in solid content) And a commercially available urethane-based resin emulsion M-589 [manufactured by Toyo Polymer Co., Ltd .: viscosity 1600 cps,

pH 7.0, solid content 30% by weight, particle size 0.12 /; yield point 113 kg / cm ² — 10%, 100% modulus 106 kg gcm ² ] 33 parts by weight (about 10 parts by weight in solid content) Except for the above, a composition for an anti-chubbing water-based coating having a PWC of 70% by weight was prepared in substantially the same manner as in Example 1. Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 1 (1).

Comparative Example 2

 A chipping-resistant aqueous coating composition having a PWC of 70% by weight was prepared in substantially the same manner as in Example 11, except that the aziridine compound SU-125F was not used.

Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 1, Table 1. The measurement results of the properties are shown in Table 3 (1).

Example 12

 In Example 11, except that instead of using 218 parts by weight of the powdered heavy calcium carbonate SL-700, 198 parts by weight of the powdered heavy calcium carbonate SL-700 and 20 parts by weight of dipsyl E-20OA as the white carbon were used. In the same manner as in Example 11, a chipping-resistant aqueous coating composition having a PWC of 70% by weight was prepared.

 Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 1 (1).

Example 13

 In Example 11, instead of using 218 parts by weight of powdered heavy calcium carbonate SL-700, 116 parts by weight of powdered heavy calcium carbonate SL-700 and 100 parts by weight of light calcium carbonate were used, and Matsumoto Microsphere F-502 was used. Except for blending parts by weight, the same procedure as in Example 11 was carried out to prepare a composition for a water-resistant tubing-resistant coating having a PWC of 70% by weight.

 Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 1 (1).

Example 14

Instead of using 218 parts by weight of powdered heavy calcium carbonate SL-700 in Example 11, 113 parts by weight of powdered heavy calcium carbonate SL-700 and 100 parts by weight of light calcium carbonate were used. In the same manner as in Example 11, except that 5 parts by weight of Scotch Light B38Z40000 was blended as a water-based composition, an aqueous coating composition having a PWC of 70% by weight was prepared. .

 Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 1 (1).

Example 15 to 16

 In Example 12, PWC was 70% by weight in substantially the same manner as in Example 12 except that the copolymer emulsions of Reference Examples 2 to 3 were used instead of using the styrene copolymer emulsion of Reference Example 1. % Of an anti-chubbing water-soluble coating composition was prepared.

 Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 1 (1).

Examples 17 to 18

 In Example 13, PWC was 70% by weight in substantially the same manner as in Example 13 except that the copolymer emulsions of Reference Examples 2 to 3 were used instead of using the styrene copolymer emulsion of Reference Example 1. % Of an anti-chubbing water-soluble coating composition was prepared.

 Various physical property tests were carried out in the same manner as in Example 1 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (1), and the properties and various physical properties of the composition are shown in Table 1 (1).

Example 19

In Example 1, the styrene copolymer emulsion of Reference Example 1 was used. Instead of using the styrene / acrylic copolymer emulsion of Reference Example 4 in the same manner as in Example 1 except that 70% by weight of PWC and 77.5% by weight of solids were used. A composition for a water-based tubing coating was prepared. Various physical property tests were performed using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (2), and the properties and various physical properties of the composition are shown in Table 2 (2). The coating film was subjected to a low-temperature baking treatment (baking at 80 ° C for 30 minutes) using a hot-air circulation dryer.

Comparative Example 3

 In Example 19, a tubing-resistant aqueous coating composition having a PWC of 70% by weight was prepared in the same manner as in Example 19, except that the aziridine compound SU-1225F was not used.

 Using the obtained aqueous coating composition, test pieces were prepared in the same manner as in Example 19, and various physical property tests were performed. The composition of the composition is shown in Table 2-2, and the properties and various physical properties of the composition are shown in Table 3-2.

Example 20

In Example 19, instead of using powder heavy calcium carbonate SL—700 2 18 parts by weight, powder heavy calcium carbonate SL—700 1 112 parts by weight and light calcium carbonate 100 parts by weight were used. Further, as a hollow polymer bead, Expanscel WE ^ 55 1 [manufactured by Nippon Philite Co., Ltd .; water content about 85% by weight; particle size about 40 ^ m) 6 parts by weight (body weight excluding water) (About 0.9 parts by weight) except that the composition was used in the same manner as in Example 19 to prepare a water-resistant coating composition having a PWC of 70% by weight. Various physical property tests were performed in the same manner as in Example 19 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2 (2). The measurement results of the properties are shown in Table 3-2.

Example 21

 In Example 19, instead of using 218 parts by weight of powdered heavy calcium carbonate SL-700, 113 parts by weight of powdered heavy calcium carbonate SL-700 and 100 parts by weight of light calcium carbonate were used, and Scotch light B38Z4000 was used as a glass bead. Except for blending 5 parts by weight, a tubing-resistant aqueous coating composition having a PWC of 70% by weight was prepared in the same manner as in Example 19.

 Various physical property tests were performed in the same manner as in Example 19 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2-2, and the properties and various physical properties of the composition are shown in Table 3-2.

Examples 22 to 23

 In the same manner as in Example 20, except that the copolymer emulsions of Reference Examples 5 to 6 were used instead of the styrene copolymer emulsion of Reference Example 4 in Example 20, the PWC was 70% by weight. A composition for a water-based coating with a chipping property was prepared.

 Various physical property tests were performed in the same manner as in Example 19 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2-2, and the properties and various physical properties of the composition are shown in Table 3-2.

Example 24

In Example 20, instead of using 133 parts by weight of the SBR polymer emulsion SN-562 (about 70 parts by weight of solid content), 137 parts by weight of Nipol 1551 of the NBR polymer emulsion was added (about 70 parts by weight of solid content). Part) In the same manner as in Example 20 except that it is used, the PWC has a 70% by weight chip resistance. A pingable aqueous coating composition was prepared.

 Various physical property tests were carried out in the same manner as in Example 19 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2-2, and the properties and various physical properties of the composition are shown in Table 3-2.

Example 2 5

 In Example 19, SBR-based polymer emulsion SN-56 21 33 parts by weight (about 70 parts by weight in solid content) and 60 parts by weight of styrene-based copolymer emulsion in Reference Example 4 (in terms of solid content) Instead of using about 30 parts by weight), instead of using SBR-based polymer emulsion SN—562 1114 parts by weight (about 60 parts by weight in solid content), 60 parts by weight of styrene-based copolymer emulsion of Reference Example 4 Parts (about 30 parts by weight in solid content) and urethane-based resin emulsion M-5893 33 parts by weight (about 10 parts by weight in solid content) except that PW A composition for a water-based coating having a resistance to chipping of 70% by weight of C was prepared.

 Various physical property tests were carried out in the same manner as in Example 19 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2-2, and the properties and various physical properties of the composition are shown in Table 3-2.

Comparative Example 4

 A chipping-resistant aqueous coating composition having a PWC of 70% by weight was prepared in substantially the same manner as in Example 25 except that the aziridine compound SU-1225F was not used.

Various physical property tests were carried out in the same manner as in Example 19 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2-2, and the properties and various physical properties of the composition are shown in Table 3-2. Example 26

 In Example 25, instead of using 218 parts by weight of powdered heavy calcium carbonate SL-700, 112 parts by weight of powdered heavy calcium carbonate SL-700 and 100 parts by weight of light calcium carbonate were used, and further, 6 parts by weight of Expanscel WE * 551 In the same manner as in Example 25, except that was added, a composition for a water-resistant coating against chippings having a PWC of 70% by weight was prepared. Various physical property tests were performed in the same manner as in Example 19 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2-2, and the properties and various physical properties of the composition are shown in Table 3-2.

Example 27

 In Example 25, instead of using 218 parts by weight of powdered heavy calcium carbonate SL-700, 113 parts by weight of powdered heavy calcium carbonate SL-700 and 100 parts by weight of light calcium carbonate were used, and Scotch light B3.8 / 4000 was used. Was prepared in the same manner as in Example 25 except that 5 parts by weight of the composition was added to the composition.

 Various physical property tests were performed in the same manner as in Example 19 using the obtained aqueous coating composition. The composition of the composition is shown in Table 2-2, and the properties and various physical properties of the composition are shown in Table 3-2.

Examples 28 to 29

In Example 26, except that the copolymer emulsions of Reference Examples 5 and 6 were used instead of using the styrene copolymer emulsion of Reference Example 4, the resistance to PWC was 70% by weight. A composition for a water-based coating with a chipping property was prepared. Various physical property tests were performed using the obtained aqueous coating composition in the same manner as in Example 19 ′. The composition of the composition is shown in Table 2-2, and the properties and various physical properties of the composition are shown in Table 3-2.

1 in Table 2

* 1 …… Mfi part for ^ ftlOOSfl part of (A-1) and (A-2)

2 in Table 2

And is directly tH.

Table 3

2 items in Table 3 Aqueous coating composition characteristic value Baking Aqueous coating composition Coating film physical condition Crack base material Chipping resistance Low temperature resistance Solid content Η Viscosity P.WC

 Limit Adhesion Normal Moisture Moisture Test No. (Weight 96) (cps) (Weight 6) (χ / 100) (kg) (kg)

Example 19 77.5 9.1 22,000 70 Low Inn ≥2000 100 35 20 ◎ Comparative Example 3 78.0 9.0 25, 000 ',, / 80 JU 例 Example 20 10ς.1 Ω y.1 ς f) f) f))) / 45 25

Example 21 78.0 9.2 28,000 .1300 40 30

Example 22 75.1 9.1 26,000 1600 each 50

Example 23 75.1 9.2 25,000 1500 40 25

Example 24 74.4 9.1 26,000 1600

Example 25 74.8 9.0 21,000 ≥2000 40

Comparative Example 4 75.3 9.1 24,000 clicks 85 20 10 〇 Example 26 72.4 9.1 25, 000 100 50 30

Example 27 74.8 9.0 27,000 h 45 35 ◎ Example 28 72.4 9.1 26,000 1500 55

Example 29 72.4 9.2 25,000 1400 45 30

Claims

1. An aqueous coating composition comprising a polymer fine particle (A) and an inorganic filler (B) dispersed in an aqueous medium, wherein the polymer fine particle (A) is

(A-1) 50 to 100% by weight of a synthetic rubber emulsion polymer particle containing 30 to 90% by weight of a conjugated diolefin unit and having a glass transition temperature of 0 ° C. or less;

 (A-2) Formula

 Knee

(I)

 In the formula,

R ¹ represents a hydrogen atom or a methyl group,

Q is Ariru group one COOR ^2, C ₆ ~ _12, or - represents CN,

R ² represents a lower alkyl group,

0 to 50% by weight of emulsion polymer particles having a glass transition temperature of at least 20 ° C and containing 30 to 99.9% by weight of a repeating unit represented by the formula:

 (A-3) urethane-based resin emulsion particles, 0 to 100 parts by weight based on 100 parts by weight of the total amount of the emulsion polymer particles (A-1) and (A-2)

And, as a crosslinking agent,

 (C) an isocyanate derivative,

An aqueous coating composition comprising: l £ w carrier paper (MM91)

2. The aqueous coating composition according to claim 1, wherein the synthetic rubber-based emulsion polymer particles (A-.1) have a glass transition temperature of -10 ° C or less.

 3. Synthetic rubber-based emulsion polymer particles (A-1)

 (a-1) a conjugated diolefin monomer;

 (a-2) an aromatic vinyl monomer and / or a cyanated vinyl monomer,

 (a-3) carboxyl group-containing ethylenic monomer and, if necessary,

 (a-4) other copolymerizable monomers,

The aqueous coating composition according to claim 1, wherein the composition is obtained by aqueous emulsion polymerization under pressure.

 4. The aqueous coating composition according to claim 3, wherein the conjugated diolefin monomer (a-1) is butadiene.

 5. The aqueous coating composition according to claim 3, wherein the aromatic vinyl monomer (a-2) is styrene, and the vinyl cyanide monomer (a-2) is acrylonitrile.

 6. The aqueous coating composition according to claim 3, wherein the carboxyl group-containing ethylene monomer (a-3) is acrylic acid, methacrylic acid, or itaconic acid.

7. The synthetic rubber-based emulsion polymer particles (A-1) are converted to the monomer (a-1) based on 100% by weight of the total amount of the monomers (a-1) to (a-4). 40 to 80% by weight, the monomer (a-2) 19.5 to 55% by weight, the monomer (a-3) 0 .:! To 10% by weight, and the monomer (a-4) 4. The aqueous coating composition according to claim 3, which is obtained by emulsion polymerization of 0 to 20% by weight. Composition.

 8. The aqueous coating composition according to claim 1, wherein the average particle size of the synthetic rubber-based emulsion polymer particles (A-1) is in the range of 0.05 to 0.5 / zm.

 9. The aqueous coating composition according to claim 1, wherein the emulsion polymer particles (A-2) contain 30 to 99.9% by weight of a unit represented by the formula (I).

 10. The aqueous coating composition according to claim 1, wherein the emulsion polymer particles (A-2) contain 0.1 to 10% by weight of units derived from a carboxyl group-containing ethylenic monomer. object.

 11. The aqueous coating composition according to claim 1, wherein the emulsion polymer particles (A-2) contain 1 to 20% by weight of a unit derived from a hydroxyl group-containing ethylene monomer.

 12. The emulsion polymer particles (A-2)

 Equation (b-1)

R ¹

CH ₂ = CQ (Π)

Wherein R ¹ and Q are as defined in claim ^1, wherein the homopolymer is hydrophobic and the glass transition temperature is 40 ° C. A monomer which is the above,

 (b-2) a carboxyl group-containing ethylenic monomer, preferably (b-3) a hydroxyl group-containing ethylenic monomer, and

 (b-4) other copolymerizable monomers,

The aqueous coating according to claim 1, wherein the aqueous coating is obtained by emulsion polymerization. Composition.

 '

13. The aqueous coating composition according to claim 12, wherein the monomer (b-1) represented by the above formula (II) is methyl methacrylate, isobutyl methacrylate, styrene or acrylonitrile. .

 14. The aqueous coating composition according to claim 12, wherein the carboxyl group-containing ethylene monomer (b-2) is acrylic acid, methacrylic acid or itaconic acid.

 15. The aqueous coating composition according to claim 12, wherein the hydroxyl group-containing ethylene monomer (b-3) is a hydroxyalkyl ester of acrylic acid or methacrylic acid having 2 to 4 carbon atoms. .

 16. The aqueous coating composition according to claim 1, wherein the glass transition temperature of the emulsion polymer particles (A-2) is 20 ° C or more and less than 60 ° C.

 17. When the emulsion polymer particles (A-2) are based on 100% by weight of the total amount of the monomers (b-1) to (b-4), the monomers (b-1) 35 to 80% by weight, the monomer (b-2) 0.5 to 5% by weight, the monomer (b-3) 1 to 20% by weight, and the monomer (b-4) 15 to 63. 17. The aqueous coating composition according to claim 16, which is obtained by emulsion polymerization of 5% by weight.

 18. The aqueous coating composition according to claim 1, wherein the glass transition temperature of the emulsion polymer particles (A-2) is 60 ° C or higher.

19. Based on the emulsion polymer particles (A-2) force, and the total amount of the above monomers (b-1) to (b-4), the monomer (b-1) 45 to 98 0.5% by weight, the monomer (b-2) 0.5 to 5% by weight, the monomer (b-3) 1 to 20% by weight, and the monomer (b-4) 0 to 30 Weight% emulsion polymerization 19. The aqueous coating composition according to claim 18, wherein the composition comprises:

 20. The aqueous coating composition according to claim 1, wherein the average particle size of the emulsion polymer particles (A-2) is in the range of 0.05 to 0.5 zm.

 21. The polymer fine particles (A) are composed of 55 to 95% by weight of synthetic rubber-based emulsion polymer particles (A-1) and 5 to 45% by weight of emulsion polymer particles (A-2). Item 2. The aqueous coating composition according to Item 1.

 22. Urethane-based resin emulsion particles (A-3) formed by reacting a chain extender with urethane prepolymer having terminal issocyanate groups obtained from a polyisocyanate compound and a polyol compound, and emulsifying the emulsion. 2. The aqueous coating composition according to claim 1, wherein the composition is:

 23. The aqueous coating composition according to claim 22, wherein the urethane resin emulsion particles (A-3) are nonionic or anionic urethane emulsion resin particles.

24. urethane resin Emarujon particles (A- 3) of the fill beam forming is the value of either the large hearing side of at 100% elongation stress and 100% elongation previous yield value, wherein at 20k gZcm ² or more 23. The aqueous coating composition according to item 22.

 25. The aqueous coating composition according to claim 1, wherein the urethane resin emulsion particles (A-3) have an average particle diameter in the range of 0.05 to 0.5 / zm.

26. The aqueous coating composition was prepared by adding the urethane resin emulsion particles (A-3) to 3 to 100 with respect to 100 parts by weight of the total amount of the emulsion polymer particles (A-1) and (A-2). 2. The aqueous coating composition according to claim 1, which contains parts by weight.

27. The aqueous coating composition according to claim 1, wherein the isocyanate derivative (C) is a water-dispersible aziridine compound or a blocked isocyanate.

 28. The aqueous coating composition according to claim 1, comprising 0.1 to 10 parts by weight of the isocyanate derivative (C) based on 100 parts by weight of the polymer fine particles (A).

 29. The aqueous coating composition according to claim 1, wherein the inorganic filler (B) contains white carbon (B-1).

30. The aqueous coating composition according to claim 29, wherein the white carbon (B-1) is a silicate compound having an average particle diameter of 200 / m or less and a specific surface area of 10 m ² / g or more.

 31. The aqueous coating composition according to claim 29, comprising 0.5 to 100 parts by weight of the white carbon (B-1) based on 100 parts by weight of the polymer fine particles (A).

 32. When the inorganic filler (B) is heavy calcium carbonate, light calcium carbonate, silica other than white carbon, alumina, kaolin, clay, silver, diatomaceous earth, My power, aluminum hydroxide, glass powder, barium sulfate and The aqueous coating composition according to claim 1, further comprising an inorganic filler (B-2) other than white carbon selected from the group consisting of magnesium carbonate.

 33. The aqueous coating according to claim 32, wherein the inorganic filler (B-2) other than white carbon is contained in an amount of 100 to 560 parts by weight based on 100 parts by weight of the polymer particles (A). Composition.

34. Add heat-expandable polymer beads and / or hollow beads (D) 2. The aqueous coating composition according to claim 1, which contains the composition.

 35. The aqueous coating composition according to claim 34, wherein the thermal expansion temperature of the thermally expandable polymer beads (D) is 60 to 180 ° C.

 36. The aqueous coating composition according to claim 34, wherein the thermally expandable polymer beads (D) have an average particle size after thermal expansion in the range of 5 to 300 / zm.

 37. The average particle size of the thermally expandable polymer beads (D) before thermal expansion is 1 ~

35. The aqueous coating composition according to claim 34, which is in the range of 50 / m.

 38. The aqueous coating composition according to claim 34, wherein the hollow beads (D) are hollow polymer beads.

39. The aqueous coating composition according to claim 38, wherein the hollow polymer beads have an average particle size in the range of 5 to 300 zm.

 40. The aqueous coating composition according to claim 34, wherein the hollow beads (D) are hollow inorganic beads.

41. The hollow average particle size of the inorganic beads aqueous coating composition according paragraph 40 claims Ru ₅ near the range of 5 to 300 m.

 42. The aqueous coating composition according to claim 34, comprising 0.1 to 40 parts by weight of the heat-expandable polymer beads and the hollow or hollow beads (D) based on 100 parts by weight of the polymer fine particles (A). .

 43. The aqueous coating composition according to claim 1, further comprising a water-proof pigment (E).

 44. The aqueous coating composition according to claim 43, wherein the water-proof pigment (E) is a low-toxic water-proof pigment selected from the group consisting of metal phosphates, metal molybdates and metal borates. object.

45. The anti-pigment (E) was added to 100 parts by weight of polymer fine particles (A). The aqueous coating composition according to claim 43, wherein the composition is contained in an amount of from 50 to 50 parts by weight.

4 6. The aqueous coating composition according to claim 1, which is a composition for aqueous coating with chipping resistance.

 4 7. A processed member coated with the aqueous coating composition according to claim 1.