JP2000154204A - Preparation of gelled polymer particulate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer particulate which can improve evenness, dropping resistance, chipping resistance and the like of a film without affecting various properties of the film. SOLUTION: A preparation method of a gelled polymer particulate comprises emulsion-polymerizing a monomer mixture of (a) a multifunctional monomer having two or more polymerizable unsaturated groups and (b) another polymerizable unsaturated monomer in the presence of a reactive emulsifier having an allyl group in the molecule. In this method, emulsion polymerization of the first monomer mixture which comprises monomers (a) and (b) and from which a polymer having a glass transition temperature of -50 to 0 deg.C is formed is followed by addition and emulsion polymerization of the second monomer mixture which comprises the rest of monomers (a) and (b) and from which a polymer having a glass transition temperature of 20 to 150 deg.C is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing gelled polymer fine particles excellent in fluidity control of a coating film and improvement in chipping resistance of the coating film, an organic solvent dispersion of the fine particles, and the gelation. The present invention relates to a coating composition containing polymer fine particles.

[0002]

2. Description of the Related Art There are known various fluidity regulators for controlling the fluidity of a paint, realizing a smooth paint surface, and preventing the paint from sagging on a vertical surface. Examples thereof include inorganic additives such as Erosil and Benton, polyamide compounds, and diurea compounds obtained by reacting a diisocyanate compound with a monoprimary amine. In addition to these fluidity modifiers, a number of gelled polymer fine particle-based fluidity modifiers have been proposed (for example, see JP-A-51-1262).
No. 87, JP-A-53-133233, JP-A-53-1
No. 33236, JP-A-56-7647, JP-A-58
-12,065, JP-A-3-66770, etc.).

However, when the above-mentioned conventional fluidity modifier is added to a coating composition, it contributes to improving the spray efficiency of the coating, preventing sagging of the coating film, and controlling the pattern of the glittering pigment. However, there are problems that the finished appearance of the coating film is deteriorated, the interlayer adhesion of the coating film when coating is applied repeatedly is reduced, and the water resistance of the coating film is reduced. Above all, in high solids coatings, it has been difficult to obtain a sufficient effect of improving flow characteristics without impairing the finished appearance of a coating film such as luster, due to the low molecular weight of the binder resin.

[0004] In the field of automotive paints, when a vehicle travels, the collision (chipping) of pebbles or the like damages the coating film of the vehicle and impairs the appearance of the coating film. When it reaches, there is a problem that rust is generated and corrosion causes puncture or peeling of the coating film.

In order to improve the resistance to the above-mentioned chipping, a method of forming a soft polyolefin lacquer type coating (chipping primer) between an electrodeposition coating film and an intermediate coating film has conventionally been used. However, in this method, it is necessary to use a high-molecular-weight polyolefin in order to obtain sufficient chipping resistance, so that the chipping primer coating has a very low heating residue, so that the organic solvent at the time of coating cannot be used. Emissions increase and there is a problem on global environmental conservation. Further, there is a problem that a step of coating and drying the chipping primer is required.

On the other hand, attempts have been made to improve the chipping resistance by adding a soft polyolefin to the intermediate coating composition. However, if the soft polyolefin is added, the compatibility with the coating material is poor, so that layer separation may occur. There has been a problem that gloss on the surface of the baked coating film disappears.

It is also conceivable to add soft gelled polymer fine particles produced by emulsion polymerization to an intermediate coating to improve chipping resistance. It is necessary to remove the water incorporated at the time of the production of the polymer. However, it was difficult to remove the water from the soft polymer fine particles.

An object of the present invention is to act as a fluidity regulator capable of achieving both smoothness and sagging resistance of a coated surface, to improve chipping resistance, to be easy to manufacture, and to have no problem in preserving the global environment. An object of the present invention is to provide a method for producing gelled polymer fine particles.

Another object of the present invention is to provide a novel coating composition which has good fluidity of coating such as smoothness of coating surface and sagging resistance and excellent chipping resistance and which has solved the above-mentioned problems of the prior art. To provide.

[0010]

Means for Solving the Problems The present inventors have made intensive studies to develop a coating composition which can solve the above-mentioned problems of the prior art. As a result, the internally crosslinked gelled polymer fine particles having a core / shell structure, having a group having surface activity incorporated into the surface of the resin particles by a chemical bond, having a specific glass transition temperature (Tg), and having the above-mentioned problem. It was found to be extremely effective in solving the problem. That is, it has good dispersion stability, and when added to the coating composition, adversely affects various properties such as the finished appearance of the coating film, interlayer adhesion, water resistance, solvent resistance, and chemical resistance. Without exerting such effects, they found that they were extremely effective in improving physical properties such as sagging resistance of paints, chipping resistance of coating films, impact resistance, and workability, and completed the present invention.

Thus, according to the present invention, (a) a polyfunctional monomer having at least two polymerizable unsaturated groups in the molecule and (b) other polymerizable unsaturated compounds other than the polyfunctional monomer (a) A monomer mixture consisting of
A method for producing gelled polymer fine particles which is subjected to emulsion polymerization in the presence of a reactive emulsifier having an allyl group in the molecule,
After emulsion polymerization of the following first monomer mixture consisting of a part of the polyfunctional monomer (a) and a part of the other polymerizable unsaturated monomer (b), the polyfunctional monomer (a) is added to the reaction system.
A method for producing gelled polymer fine particles, characterized by adding the following second monomer mixture comprising the remaining amount of the polymerizable unsaturated monomer (b) and emulsion polymerization. . A second monomer mixture, a polymer formed from the second monomer mixture , wherein the glass transition temperature of the polymer formed from the first monomer mixture first monomer mixture is in the range of −50 to 0 ° C. The glass transition temperature is in the range of 20-150C.

Further, according to the present invention, there is provided an organic solvent dispersion of gelled polymer fine particles obtained by dispersing gelled polymer fine particles obtained by the above production method in an organic solvent.

Further, according to the present invention, a gel obtained by the above-mentioned production method, which is not dissolved in a (A) diluent (C) solution of the following film-forming binder resin (B) but is stably dispersed. Polymer fine particles, (B) the following diluent (C)
Film-forming binder resin dissolved in water and (C)
A coating composition comprising a diluent in which the binder resin (B) is dissolved is provided.

Hereinafter, a method for producing the gelled polymer fine particles provided by the present invention, a coating composition, and the like will be described.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the method for producing the gelled polymer fine particles of the present invention will be described in detail.

In the method for producing gelled polymer fine particles of the present invention, (a) a polyfunctional monomer having at least two polymerizable unsaturated groups in a molecule and (b) a polyfunctional monomer other than the polyfunctional monomer (a) A monomer mixture comprising other polymerizable unsaturated monomers is emulsion-polymerized in the presence of a reactive emulsifier having an allyl group in the molecule. In this emulsion polymerization, after a first monomer mixture composed of a part of the polyfunctional monomer (a) and a part of the other polymerizable unsaturated monomer (b) is emulsion-polymerized, the polyfunctional monomer ( A second monomer mixture consisting of the remaining amount of a) and the remaining amount of the other polymerizable unsaturated monomer (b) is added to carry out emulsion polymerization.

The monomer (a) to be emulsion-polymerized is not particularly limited as long as it is a polyfunctional monomer having at least two polymerizable unsaturated groups in the molecule. Examples include di- or higher polyesters with unsaturated monocarboxylic acids, di- or higher polyesters with polybasic acids and polymerizable unsaturated alcohols, and aromatic compounds substituted with two or more vinyl groups, and the like. As, ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, trimethylolpropane triacrylate,
Trimethylolpropane trimethacrylate, 1,4-
Butanediol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate,
Pentaerythritol tetramethacrylate, glycerol dimethacrylate, glycerol diacrylate,
Glycerol allyloxydimethacrylate, 1,1,1
-Trishydroxymethylethane diacrylate, 1,
1,1-trishydroxymethylethane triacrylate, 1,1,1-trishydroxymethylethanetrimethacrylate, 1,1,1-trishydroxymethylpropane diacrylate, 1,1,1-trishydroxymethylpropane triacrylate, 1,1,1-trishydroxymethylpropane dimethacrylate, 1,1,
Examples thereof include 1-trishydroxymethylpropane trimethacrylate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, diallyl terephthalate, diallyl phthalate, and divinylbenzene. These monomers can be used alone or in combination of two or more.

Of these monomers, triethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6 -Hexanediol diacrylate is desirable, and 1,6-hexanediol diacrylate is particularly desirable.

In the present invention, "... (meth) acrylate" means "acrylate or methacrylate".

The monomer (b) to be emulsion-polymerized is a monomer other than the polyfunctional monomer (a), ie, 1
A monomer having one polymerizable unsaturated group in the molecule. Specific examples thereof include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-, iso- or tert. -Butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
Acrylic or methacrylic acid such as lauryl (meth) acrylate having 1 to 24 carbon atoms in alkyl or cycloalkyl ester; carboxyl group-containing polymerizable polymer such as acrylic acid, methacrylic acid, maleic acid, itaconic acid and crotonic acid Saturated monomer; acrylic acid or methacrylic acid having 1 to 8 carbon atoms, such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, and 4-hydroxybutyl methacrylate Hydroxyalkyl esters; acrylamide, methacrylamide, N-methylacrylamide, N-ethylmethacrylamide, diacetoneacrylamide, N-methylolacrylamide, N
Polymerizable amides such as methylol methacrylamide, N-butoxymethylacrylamide or methacrylamide;
Nitrogen-containing alkyl (meth) acrylates such as N, N-dimethylaminoethyl (meth) acrylate; polymerizable nitriles such as acrylonitrile and methacrylonitrile; glycidyl (meth) acrylate, glycidyl acrylamide, glycidyl methacrylamide, allyl glycidyl ether and the like Glycidyl group-containing polymerizable unsaturated compounds; aromatic polymerizable unsaturated compounds such as styrene, vinyltoluene, α-methylstyrene and t-butylstyrene; vinyl carboxylate esters such as vinyl acetate and vinyl propionate; ethylene and propylene Α-olefins such as butadiene and isoprene; diene compounds such as butadiene and isoprene; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane and γ-methacryloyloxypropyltrimethoxy. Silane, .gamma. acryloyloxypropyltrimethoxysilane, mention may be made of such hydrolyzable silyl group-containing polymerizable unsaturated monomers such as vinyl triacetoxy silane. These monomers are
They can be used alone or in combination of two or more.

In the method of the present invention, at the time of emulsion polymerization, first, the first monomer mixture is emulsion-polymerized. First
Is a monomer mixture composed of a part of the polyfunctional monomer (a) and a part of the other polymerizable unsaturated monomer (b), and the glass transition temperature of a polymer formed from the monomer mixture. Is in the range of −50 to 0 ° C., preferably −40 to −10 ° C.

The first monomer mixture is emulsion-polymerized, usually until the polymerization rate of the first monomer mixture becomes 80% or more, preferably 90% or more, and then the second monomer mixture is added to the reaction system. To perform emulsion polymerization. Second
Is composed of the remaining amount of the polyfunctional monomer (a) and the remaining amount of the other polymerizable unsaturated monomer (b),
The glass transition temperature of the polymer formed from the second monomer mixture is selected to be in the range of 20-150C, preferably 50-130C.

The glass transition temperature of each of the above polymers can be measured using a differential scanning calorimeter (DSC). For example, using a Seiko Co., Ltd. differential scanning calorimeter "DSC220", the polymer was measured for the change in calorific value at a heating rate of 10 ° C./min, and the temperature at which the calorie change was １ ／ was measured. It can be determined by setting the glass transition temperature (Tg).

In each of the first monomer mixture and the second monomer mixture used in the emulsion polymerization, the mixing ratio of the polyfunctional monomer (a) and the other polymerizable unsaturated monomer (b) is strictly defined. Although not limited, it is generally preferred that the amount be within the following range.

Monomer (a): 1 to 99% by weight, preferably 3 to 30% by weight, more preferably 5 to 20% by weight, monomer (b): 1 to 99% by weight, preferably 70 to 9%
7% by weight, more preferably 80-95% by weight.

The mixing ratio of the first monomer mixture and the second monomer mixture used in the emulsion polymerization may be in the range of 10/90 to 90/10 by weight of the former / the latter. It is suitable.

The reactive emulsifier containing an allyl group in the molecule used in the emulsion polymerization of the monomers (a) and (b) includes, for example, those belonging to the following groups.

I) Allyl group-containing anionic reactive emulsifier [0028] As a typical example of the allyl group-containing anionic reactive emulsifier, the following general formula or

[0029]

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In the formula, R ₁ represents hydrogen or a methyl group, R ₂ represents a hydrocarbon group or a hydrocarbon having a substituent or an organic group containing an oxyalkylene group, and A represents an alkylene having 2 to 4 carbon atoms. Represents a group or a substituted alkylene group, n is 0 or a positive number, M represents an alkali or alkaline earth metal, ammonium, an organic amine base, or an organic quaternary ammonium base, and m represents M A sulfonic acid salt represented by the following general formula or

[0031]

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In the formula, R ₁ represents a hydrocarbon group, a phenyl group, an amino group or a carboxylic acid residue which may have a substituent, R ₂ represents a hydrogen atom or a methyl group, and A has 2 carbon atoms. Represents 4 to 4 alkylene groups, n is a positive number from 0 to 100, M represents a monovalent or divalent cation, and m represents an ionic value of M, a sulfosuccinic acid diester salt represented by the formula: ; Or the following general formula

[0033]

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In the formula, R ₁ represents an alkyl group, an alkenyl group or an aralkyl group having 4 to 18 carbon atoms;
₂ represents hydrogen or an alkyl, alkenyl, or aralkyl group having 4 to 18 carbon atoms, and A represents 2 to 2 carbon atoms.
4 represents an alkylene group or a substituted alkylene group,
n is an integer of 2 to 200, M is an alkali metal atom,
And a compound represented by NH or an alkanolamine residue. These are known per se (for example, Japanese Patent Publication No. 49-46291, Japanese Patent Application Laid-Open No.
See JP-A-203960, JP-A-62-221431, JP-A-63-23725 and the like. ), "Eleminor JS-2" (trade name, manufactured by Sanyo Chemical Industries, Ltd.), "Latemul S" series (trade name, manufactured by Kao Corporation), "Aqualon HS" series (trade name, Daiichi Kogyo Seiyaku Co., Ltd.) Commercially available.

II) Allyl group-containing cationic reactive emulsifier As typical examples of the allyl group-containing cationic reactive emulsifier,
The following general formula

[0036]

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In the formula, R ₁ represents an optionally substituted hydrocarbon group having 8 to 22 carbon atoms, R ₂ and R ₃ represent an alkyl group having 1 to ₃ carbon atoms, and R ₄ represents hydrogen. atom or a methyl group,, X ^- represents a monovalent anion,
And a reactive emulsifier having a quaternary ammonium salt represented by This is known per se (see JP-A-60-78947), and is commercially available, for example, as "Latemul K-180" (trade name, manufactured by Kao Corporation).

III) Allyl group-containing nonionic reactive emulsification
As a representative example of the nonionic reactive emulsifier containing an allyl group,
The following general formula

[0039]

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[0040] In the formula, R ₁ represents an alkyl group, alkenyl group or aralkyl group having 4 to 18 carbon atoms, R ₂
Represents hydrogen or an alkyl group, an alkenyl group or an aralkyl group having 4 to 18 carbon atoms, A represents an alkylene group or a substituted alkylene group having 2 to 4 carbon atoms, and n is an integer of 2 to 200. Compounds can be mentioned. This is known per se (Japanese Unexamined Patent Publication No.
No. 2-100502), for example, “H-3355
N "(trade name, manufactured by Daiichi Kogyo Seiyaku).

In the above emulsion polymerization, a reactive emulsifier containing an acrylic group, which is a relatively low reactive group,
Any of the above-mentioned anionic, cationic, and nonionic reactive emulsifiers can be widely used without being limited to those exemplified as the representative examples above, but the reaction gradually incorporated into the polymer during polymerization. Suitable emulsifiers are suitable, and in the present invention, anionic or cationic reactive emulsifiers are preferred.

Nonionic reactive emulsifier Anionic reactive emulsifier or cationic reactive emulsifier can be mixed and used in an arbitrary ratio, and the mixing ratio is appropriately selected according to desired characteristics.

The amount of the reactive emulsifier used can be used alone or as a mixture of a cationic reactive emulsifier and a nonionic reactive emulsifier or a mixture of an anionic reactive emulsifier and a nonionic reactive emulsifier. When using,
The total amount is generally in the range of 0.1 to 30 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the monomers (a) and (b) constituting the gelled polymer fine particles. It is appropriate to do.

In the above emulsion polymerization, a polymerization initiator is usually used. As the polymerization initiator, the following general formula

[0045]

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In the formula, X represents a linear or branched alkylene group having 2 to 12 carbon atoms, or

[0047]

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In the formula, a water-soluble azoamide compound represented by the formula wherein at least one of X ¹ , X ² and X ³ is a hydroxyl group and the remainder is hydrogen is particularly suitable. These are known per se (see JP-A-61-218618 and JP-A-61-63643).
It is commercially available as a series (trade name, manufactured by Wako Pure Chemical Industries, Ltd.). The amount of the polymerization initiator to be used is apparent in the art, and generally, the optimum necessary amount is 1 to the total of the monomers (a) and (b) constituting the gelled polymer fine particles.
It is in the range of 0.1 to 3 parts by weight with respect to 00 parts by weight.

The emulsion polymerization of the monomers (a) and (b) can be carried out by a per se known emulsion polymerization method for producing an acrylic copolymer. For example, the first monomer mixture is prepared in an aqueous medium in the presence of a reactive emulsifier containing an allyl group and a water-soluble azoamide compound polymerization initiator, usually at about 50-100 ° C, preferably 80-9 ° C.
After conducting the emulsion polymerization reaction at a reaction temperature of 5 ° C. for about 15 minutes to about 20 hours, the second monomer mixture is added to the system, and the emulsion polymerization reaction is continued for about 1 to about 20 hours. be able to.

The aqueous dispersion of the gelled polymer particles obtained by the emulsion polymerization is based on the total weight of the aqueous dispersion.
Usually, it has a resin solids content of about 10-40% by weight. The particle size of the gelled polymer fine particles in the aqueous dispersion is generally 500 n
m, preferably in the range of 50 to 200 nm.
The particle size can be easily adjusted by adjusting the type and amount of the reactive emulsifier having an allyl group in the molecule.

According to the production method of the present invention, a low glass transition temperature core component, which is a polymer of the first monomer mixture,
And a gelled polymer fine particle having a core / shell structure having a shell component having a high glass transition temperature, which is a polymer of the second monomer mixture. A core / shell structure is defined as a polymer of a first monomer mixture and a second
Is incompatible with the polymer of the monomer mixture of
Means a structure in which the polymer of the monomer mixture governs the particle surface.

The gelled polymer fine particles obtained by the production method of the present invention preferably have the above-mentioned core / shell structure, but also include those having no core / shell structure.

The glass transition temperature of the gelled polymer fine particles obtained by the production method of the present invention can be determined by placing an aqueous dispersion of the gelled polymer fine particles in a petri dish and drying in a 60 ° C. electric hot air dryer. Crushed gelled polymer resin,
Using a differential scanning thermal analyzer “DSC220” manufactured by Seiko Co., the change in calorific value was measured at a heating rate of 10 ° C./min, and the temperature at which the change in calorie was を was taken as the glass transition temperature (Tg). Can be obtained by:

The gelation polymer fine particles obtained by the production method of the present invention have one peak indicating the glass transition temperature,
There may be two or three, and in the case of two or three, it is considered to have a core / shell structure. In the case of two or three, the low temperature peak indicates the core portion and the high temperature peak indicates the shell portion. In the case of three, the middle temperature peak indicates the core portion and the shell where the core portion and the shell portion are mixed. Indicates the boundary with the part. When the number of peaks is one, it is considered that the core portion and the shell portion are in a mixed state or the ratio of the core portion or the shell portion is very small. For example, when the ratio of the shell portion is very small, the mixing ratio of the second monomer mixture forming the shell portion is small,
No peak as a shell portion appears, and only one peak is present.

Next, an organic solvent dispersion of the gelled polymer fine particles of the present invention will be described. The organic solvent dispersion of the gelled polymer particles of the present invention, the aqueous dispersion of the gelled polymer particles obtained by the emulsion polymerization, after evaporating water by a spray drying method or simple drying, the resin solids This can be done by removing the fraction and then redispersing it in an organic solvent. In that case, a polymer such as an acrylic resin or a polyester resin can be added to prevent aggregation of the particles.

As the organic solvent used for the redispersion, an organic solvent that does not dissolve the gelled polymer fine particles is used. For example, a solvent that can be used as a diluent (C) described below is used. it can.

Hereinafter, the coating composition of the present invention will be described in detail. The coating composition of the present invention contains the gelled polymer fine particles as the component (A), the film-forming binder resin as the component (B), and the diluent as the component (C).

Film-forming binder resin (B): The film-forming binder resin, which is the component (B) in the composition of the present invention, can be blended with a coating material to form a coating film, and (C) There is no particular limitation as long as the resin can be dissolved in the diluent which is a component, and it can be selected from a wide range,
Any of a thermosetting resin and a room temperature drying type resin may be used.

As the thermosetting resin, for example, a system in which a hydroxyl group-containing resin such as an acrylic resin, an alkyd resin, a polyester resin or an epoxy resin is combined with a crosslinking agent such as an amino resin, a polyisocyanate compound or a blocked polyisocyanate compound is used. A system in which a high acid value compound and an oxirane group-containing resin are combined; and a hydrolyzable silyl group-containing resin.

Examples of the room temperature drying type resin include an oxidation curing type alkyd resin and a lacquer curing type acrylic resin.

As the film-forming binder resin (B), among the above resins, a thermosetting resin obtained by combining a crosslinking agent with an acrylic resin, an alkyd resin or a polyester resin containing a hydroxyl group is preferable.

Diluent (C): The diluent as the component (C) in the composition of the present invention dissolves the film-forming binder resin (B), but dissolves the gelled polymer fine particles (C). Liquid diluent that stably disperses
Included are any liquid mixtures conventionally used as solvents in coating compositions. Specifically, for example,
Water; aromatic hydrocarbons such as toluene and xylene; petroleum fractions in various boiling ranges containing a substantial proportion of aromatic components; aliphatic hydrocarbons such as hexane, heptane, octane; butyl acetate, ethylene glycol diacetate;
Ester solvents such as ethylene glycol monoethyl ether acetate; ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, diethylene glycol monobutyl ether and propylene glycol monomethyl ether; methanol, ethanol, n-propanol, isopropanol, n-butanol; Alcohol solvents such as isobutanol, t-butanol and hexanol; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone. These can be used alone or as a mixture.

The composition of the present invention can be obtained by uniformly mixing the gelled polymer fine particles (A), the binder resin (B) and the diluent (C). When the diluent (C) is water, an aqueous dispersion of gelled polymer fine particles obtained by emulsion polymerization can be used as it is as the gelled polymer fine particles (C). When is an organic solvent, a gelled polymer fine particle (C) is usually an organic solvent dispersion of the gelled polymer fine particles.

In the composition of the present invention, the mixing ratio of the gelled polymer fine particles (A) and the binder resin (B) is generally in the range of 100 parts by weight of the binder resin (B). ) Is in the range of 1 to 50 parts by weight, preferably 5 to 40 parts by weight, more preferably 5 to 30 parts by weight. The mixing ratio of the diluent (B) is such that the binder resin (B) can be uniformly dissolved, and the gelled polymer fine particles (A) are mixed in the diluent (C) solution of the binder resin (B). The diluent (C) is not particularly limited as long as it is a quantitative ratio that can be stably dispersed, but from the viewpoint of ease of handling and storage stability,
Usually, 40 parts by weight per 100 parts by weight of the binder resin (B)
It is desirably in the range of 400 parts by weight.

The coating composition of the present invention comprises the gelled polymer fine particles (A), the binder resin (B) and the diluent (C).
These three components are contained as essential components. In addition to these essential components, if necessary, an organic polymer fine particle dispersion (generally, an organic polymer fine particle dispersion which may be gelled in the interior of the organic liquid) NAD), a pigment, a surface conditioner, a catalyst for accelerating curing, a cissing inhibitor, an antifoaming agent, a light stabilizer, an ultraviolet absorber, a fluidity regulator, an antioxidant, and the like.

The coating composition of the present invention can be applied directly to an object to be coated, but it can be applied to a primer coating such as an electrodeposition coating (anionic or cationic) or a thermosetting coating. It is preferable to apply the intermediate coating composition on the cured intermediate coating film. As a coating machine for coating the coating composition of the present invention, an atomization type coating machine is preferable, for example,
Examples include an air spray coater, an airless spray coater, and an air atomizing or rotating electrostatic coater.

[0067]

The present invention will be specifically described below with reference to examples and comparative examples. Hereinafter, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified.

Examples 1 to 6 In a 5 L flask equipped with a stirrer, a thermometer, a condenser tube and a heating mantle, 2,890 parts of deionized water and "Latemul S-180A" (trade name, manufactured by Kao Corporation, trade name: sulfone) 16 parts of an aqueous allyl group-containing anionic reactive emulsifier (solid content: 50%) was added, and the mixture was heated to 90 ° C. while stirring. The water-soluble azoamide polymerization initiator “VA-0” is contained therein.
86 "(trade name, manufactured by Wako Pure Chemical Industries, Ltd., 2,2'-
Azobis [2-methyl-N- (2-hydroxyethyl)
-Propionamide]), 1/3 of the aqueous solution obtained by dissolving 10 parts in 200 parts of deionized water was added. After 15 minutes, dropping of the remaining amount (2/3 amount) of the first monomer mixture and the above-mentioned aqueous solution of the polymerization initiator shown in Table 1 was started. First
200 parts per hour of the monomer mixture of
The polymerization initiator aqueous solution was dropped over 4.5 hours.

After the completion of the dropwise addition of the first monomer mixture, 30
After the elapse of minutes, subsequently, while maintaining the polymerization temperature at 90 ° C,
The second monomer mixture shown in Table 1 was dropped at a rate of 200 parts per hour. After the dropping of the aqueous polymerization initiator solution, the temperature was further maintained at 90 ° C. for 30 minutes, then cooled to room temperature, taken out using a filter cloth, and the water of the gelled polymer fine particles having a solid content of 20% and a particle diameter of about 80 nm was obtained. Dispersion (A-
1) to (A-6) were obtained.

Aqueous dispersion of gelled polymer fine particles (A-1)
(A-6) was dried in a 60 ° C. electric hot air dryer on a stainless steel vat, and was taken out as a solid resin. At this time, the aqueous dispersion of the gelled polymer particles (A-
The drying properties of 1) to (A-6) were tested at 60 ° C., and the results are shown in Table 1. Dryability was evaluated according to the following criteria. ：: A powdery dry substance without stickiness was obtained. X: A dry filmy substance with stickiness was obtained.

Then, the solid resin obtained by drying as described above was used as “Swazol 1500” (Cosmo Oil Co., Ltd.).
Made, trade name, aromatic hydrocarbon solvent) / butyl acetate / 3
-Methoxybutyl acetate / n-butanol = 25 /
Dispersed in a mixed solvent of 25/25/25 (weight ratio) to prepare organic solvent dispersions (MG1) to (MG6) of gelled polymer fine particles having a solid concentration of 10%, respectively.

An aqueous dispersion of gelled polymer particles was placed in a Petri dish, dried in an electric hot air dryer at 60 ° C., and the resulting gelled polymer resin was pulverized. 10 ° C. using a thermal analyzer “DSC220”
Change in calorie at a heating rate of 1 / min.
Table 1 also shows the glass transition temperature (Tg) of the gelled polymer resin obtained by setting the temperature at / 2 as the glass transition temperature (Tg).

In Table 1, the symbols of the monomer components have the following meanings.

1,6-HDDA: 1,6-hexanediol diacrylate n-BA: n-butyl acrylate 2-EHA: 2-ethylhexyl acrylate 2-HEA: 2-hydroxyethyl acrylate St: styrene MMA: methyl methacrylate

[0075]

[Table 1]

Comparative Example 1 2,890 parts of deionized water and 16 parts of "Latemul S-180A" were added to a 5 L flask equipped with a stirrer, thermometer, condenser and heating mantle, and the temperature was raised to 90 ° C. while stirring. did. The water-soluble azoamide polymerization initiator “V
One-third of an aqueous solution of 10 parts of "A-086" dissolved in 200 parts of deionized water was added. After 15 minutes, the dropping of the remaining amount (2/3 amount) of the monomer mixture comprising 80 parts of 1,6-hexanediol diacrylate, 680 parts of n-butyl acrylate and 40 parts of styrene and the polymerization initiator aqueous solution was started. The monomer mixture was dropped over 4 hours and the polymerization initiator aqueous solution was dropped over 4.5 hours, and the polymerization temperature was kept at 90 ° C. After the dropping of the aqueous polymerization initiator solution, the mixture was kept at 90 ° C. for further 30 minutes, cooled to room temperature, taken out using a filter cloth, and gelled polymer fine particles having a solid content of 20% and a particle diameter of about 80 nm. An aqueous dispersion (AC-1) was obtained.

An aqueous dispersion of gelled polymer fine particles (AC-
1) was dried on a stainless steel vat in an electric hot-air dryer at 60 ° C., which resulted in a highly sticky and sticky film-like dried product. The 60 ° C. drying property was ×, and the glass transition temperature ( Tg) was −20 ° C.

Comparative Example 2 To a 5 L flask equipped with a stirrer, a thermometer, a condenser and a heating mantle, 2,890 parts of deionized water and 16 parts of a reactive emulsifier “Latemul S-180A” were added, and the mixture was stirred at 90 ° C. Temperature. To this, 1/3 of an aqueous solution obtained by dissolving 10 parts of a water-soluble azoamide polymerization initiator "VA-086" in 200 parts of deionized water was added. After 15 minutes, 1,6
-Remaining amount of a monomer mixture consisting of 80 parts of hexanediol diacrylate, 160 parts of n-butyl acrylate and 560 parts of styrene and the remaining amount of a polymerization initiator aqueous solution (2/3)
Volume) was started. The monomer mixture was dropped over 4 hours and the polymerization initiator aqueous solution was dropped over 4.5 hours, and the polymerization temperature was kept at 90 ° C. After the completion of the dropwise addition of the polymerization initiator aqueous solution, 9
After maintaining at 0 ° C., the mixture was cooled to room temperature and taken out using a filter cloth to obtain an aqueous dispersion (AC-2) of gelled polymer fine particles having a solid content of 20% and a particle diameter of about 80 nm.

An aqueous dispersion of gelled polymer fine particles (AC-
2) was dried on a stainless steel vat in an electric hot air dryer at 60 ° C., and was taken out as a solid resin. 6 at this time
The drying property at 0 ° C. is ○, and the glass transition temperature (Tg) is 10
It was 0 ° C.

Thereafter, the obtained solid resin was washed with “Swazol 1500” / butyl acetate / 3-methoxybutyl acetate / n-butanol = 25/25/25/25.
(Weight ratio) in a mixed solvent of 10% solids concentration
To prepare an organic solvent dispersion MGC2 of the gelled polymer particles.

With respect to the organic solvent dispersions of the gelled polymer fine particles having a solid content of 10% obtained in Examples 1 to 6 and Comparative Example 2, the viscosities (mPa · s) and thixotropy index values of these organic solvent dispersions (Ti value, ratio of viscosity at 6 rpm to viscosity at 60 rpm in a B-type viscometer at 20 ° C.) and the particle size (nm) of gelled polymer fine particles in acetone were measured. Are shown in Table 2 below.

[0082]

[Table 2]

Production Example 1 (Production of Polyester Resin Solution a) A polyester resin production apparatus equipped with a heating device, a stirrer, a reflux device, a water separator, a rectification tower, a thermometer and the like was charged with 92.4 hexahydrophthalic anhydride. Parts (0.6 mol), 34.0 parts (0.23 mol) of phthalic anhydride, 19.0 parts (0.13 mol) of adipic acid, 85.3 parts (0.82 mol) of neopentyl glycol, 24.1 parts (0.18 mol) of methylolpropane were charged and heated. When the raw materials are melted and stirring becomes possible, stirring is started and the temperature of the reaction vessel is raised to 23.
The temperature was raised to 0 ° C. The temperature was raised at a uniform rate from 160 ° C. to 230 ° C. over 3 hours. The produced condensed water was distilled out of the system through the rectification column. When the temperature reached 230 ° C., the temperature was kept at 230 ° C. and stirring was continued for 2 hours. Thereafter, xylene was added to the reaction tank, and the reaction was continued by switching to the solvent condensation method. When the acid value reached 7, the reaction was terminated and cooled. After cooling, 145 parts of xylene was added to obtain a polyester resin solution a having a solid content of about 60%.

Production Example 2 (Production of Acrylic Resin Solution b) 40 parts of 2-ethoxyethyl acetate was charged into an acrylic resin producing apparatus equipped with a stirrer, a thermometer, a reflux condenser, etc., and heated to 135 ° C. Thereafter, a mixture of the following monomer, solvent and polymerization initiator was added over 3 hours.

Styrene 10 parts Isobutyl methacrylate 30 parts n-butyl methacrylate 12 parts 2-ethylhexyl methacrylate 20 parts 2-hydroxyethyl methacrylate 25 parts Methacrylic acid 3 parts 2-ethoxyethyl acetate 50 parts 2,2′-azobisisobutyro Nitrile 10 parts After the addition of the above mixture was completed, the reaction was further continued at 135 ° C. for 1 hour, and then the mixture was composed of 10 parts of 2-ethoxyethyl acetate and 0.6 part of 2,2′-azobisisobutyronitrile. The mixture was added over 30 minutes. After the addition,
After further reacting for 2 hours, 2-ethoxyethyl acetate was distilled off under reduced pressure to obtain an acrylic resin solution b having a resin solid content of about 65% and Gardner viscosity YZ (25 ° C.).

Production Example 3 (Production of Acrylic Resin Solution c) 40 parts of xylene was charged into an acrylic resin production apparatus equipped with a stirrer, thermometer, reflux condenser, etc., and heated and stirred.
After the temperature reached ° C, a mixture of the following monomer, solvent and polymerization initiator was added over 3 hours.

Styrene 15 parts Methyl methacrylate 20 parts Ethyl acrylate 30 parts n-butyl methacrylate 21 parts 2-hydroxyethyl methacrylate 12 parts Acrylic acid 2 parts Xylene 50 parts 2,2′-azobisisobutyronitrile part Addition of the above mixture After the completion, the reaction was further continued at 125 ° C. for 1 hour, and then a mixture of 10 parts of xylene and 0.6 part of 2,2′-azobisisobutyronitrile was added over 30 minutes. After the addition was completed, the mixture was further reacted for 2 hours and then cooled to obtain an acrylic resin solution c having a resin solid content of about 50% and a Gardner viscosity Y (25 ° C.).

Preparation of Paint Base Preparation Example 1 Pebble ball milling was performed using the polyester resin solution a obtained in Production Example 1, and the amount of xylene was adjusted so that the paint viscosity at 20.degree. Thus, a paint base (P1) was prepared.

Polyester resin solution a having a solid content of about 60% a 117 parts Uban 20SE-60 (* 1) 50 parts Titanium white JR-602 (* 2) 80 parts Silicon oil KP-322 (* 3) 0.01 parts xylene Part X (* 1) Uban 20SE-60: manufactured by Mitsui Chemicals, Inc.
Butylated melamine resin solution, 60% solids.

(* 2) Titanium White JR-602: Titanium White, manufactured by Teikoku Chemical Co., Ltd.

(* 3) Silicone oil KP-322: Silicone defoamer manufactured by Shin-Etsu Chemical Co., Ltd.

Preparation Examples 2 to 3 The same procedures as in Preparation Example 1 were carried out except that the formulations shown in Table 3 below were used, and the paint bases (P2) and (P
3) was prepared.

(Note) in Table 3 has the following meanings.

(* 4) Uban 28SE-60: a butylated melamine resin solution, manufactured by Mitsui Chemicals, Inc., solid content 60
%.

(* 5) Organic yellow pigment: trade name “IRGAZIN YELLOW 3RLT- manufactured by Ciba Geigy Co., Ltd.
N ".

(* 6) Aluminum paste A: Aluminum paste manufactured by Toyo Aluminum Co., Ltd., trade name "Aluminum paste # 4919".

(* 7) Aluminum paste A: Aluminum paste manufactured by Toyo Aluminum Co., Ltd., trade name “Aluminum paste # 55-519”.

[0098]

[Table 3]

Preparation of Coating Composition Example 7 The organic solvent dispersion (MG1) of the gelled polymer fine particles having a solid content of 10% obtained in Example 1 was added to the coating base (P1) obtained in Preparation Example 1. To the resin content 1 in the paint base (P1).
One part (1 part) of the resin component of the gelled polymer
PHR) is mixed under stirring, and the coating composition (P
1-MG1) was prepared.

Examples 8 to 14 and Comparative Examples 3 to 8 Each coating composition was prepared in the same manner as in Example 7, except that the compositions shown in Table 4 were used.

Table 4 also shows the results of storage stability tests of the paints obtained in Examples 7-14 and Comparative Examples 3-8. The storage stability of the paint was evaluated by visually observing the paint condition after storage for 2 months at room temperature (20 ° C.) in a closed container.

：: No sedimentation / separation is observed in the paint. Δ: A slight sedimentation / separation is observed in the paint.

[0103]

[Table 4]

Preparation of Coating Material An epoxy resin-based cationic electrodeposition paint was applied to a cold-rolled steel sheet treated with zinc phosphate by an electrodeposition coating method so as to have a dry film thickness of 20 μm, and baked at 170 ° C. for 20 minutes. Was. Then, after polishing the coated surface with # 400 sandpaper,
The coated surface was wiped with gauze impregnated with petroleum benzine and degreased. On this degreased coated surface, an aminoalkyd resin-based intermediate coating for automobiles was applied to a dry film thickness of 30 μm and baked at 140 ° C. for 20 minutes. Then # 400
The coated surface was polished with sandpaper, dried with water and washed with petroleum benzene to obtain a coating material.

Examples 7-14 using the above coating materials
The following tests were performed on the coating compositions obtained in Comparative Examples 3 to 8.

Test Example 1 An air spray gun [Wider W71] was applied to the above coating material.
(Manufactured by Iwata Coating Machine Industry Co., Ltd.), the coating composition obtained in Example 7 was applied to a dry film thickness of about 40 μm, and left at room temperature for 10 minutes. It was baked at 140 ° C. for 30 minutes in a hot air dryer. At this time, both a material that was painted and baked with the coating material standing almost vertically and a material that was painted and baked with the coating material horizontal were prepared. The glossiness of the painted surface was tested for both painted plates, and the painted plate which was horizontally painted and baked was tested for recoat adhesion, water resistance and chipping resistance.

[0107] The sagging limit film thickness was measured by setting the coating material almost vertically, applying a gradient coating so that the film thickness gradually increased, and leaving the coated plate at room temperature for 10 minutes. The test was performed by observing the coated surface of the coated plate which had been baked at 140 ° C. for 30 minutes. The thickness at the place where the sagging starts was defined as the sagging limit film thickness.

Test Examples 2 to 4 and Comparative Test Examples 1 and 2 The test was carried out in the same manner as in Test Example 1 except that the coating composition used was as shown in Table 5.

Test Example 5 The coating composition (metallic coating) obtained in Example 14 was applied to the above-mentioned coating material by an air spray gun [Wider W71] so that the dry film thickness became about 20 μm. The coating composition (clear coating) obtained in Example 11 was applied on the uncured coating film left for 5 minutes by an air spray gun so that the dry film thickness became about 40 μm, and left at room temperature for 10 minutes. And baked at 140 ° C. for 30 minutes. At this time, both a material that was painted and baked with the coating material standing almost vertically and a material that was painted and baked with the coating material horizontal were made. A test for the glossiness of the coated surface was performed on both coated plates, and the coated plate that was horizontally painted and baked was tested for recoat adhesion, water resistance and chipping resistance.

The sagging limit film thickness was measured by setting the coating material almost vertically and applying the coating composition (metallic paint) obtained in Example 14 so that the dry film thickness was about 20 μm. Example 1 was placed on the uncured coating film left at room temperature for 2 minutes.
The paint composition (clear paint) obtained in 1 was applied by an air spray gun so as to gradually increase the film thickness.
After leaving the plate at room temperature for
This was performed by observing the coated surface of the coated plate baked at 30 ° C. for 30 minutes. The thickness at the place where the sagging starts was defined as the sagging limit film thickness.

Test Examples 6 and 7 and Comparative Test Examples 3 to 6 Tests were carried out in the same manner as in Test Example 5, except that the types of metallic paint and clear paint used were as shown in Table 6.

The test results in Test Examples 1 to 7 and Comparative Test Examples 1 to 6 are shown in Tables 5 and 6 below.

In Tables 5 and 6, the glossiness, recoat adhesion, water resistance and chipping resistance of the coated surface were tested according to the following test methods.

Test method : Gloss on painted surface: The gloss and sharpness of the painted surface were evaluated by a 60 degree gloss and a PGd value. 60 degree gloss: JIS K5400 7.6 (1990)
The degree of gloss of the coating film and the reflectance when the incident angle and the reflection angle were each 60 degrees were measured in accordance with the prescribed 60-degree specular glossiness. PGd value: JCR1-GGD-116 type G
The angle was fixed at 55 degrees using a d-meter (sold by Nippon Color Research Institute) and measured. The higher the value, the better the sharpness.

Recoat adhesion: 30 minutes at 160 ° C.
After overbaking for a minute and allowing it to cool at room temperature, apply the same paint to the same thickness as the paint that formed the outermost coating film and bake it at 140 ° C for 30 minutes. A cross cut reaching the substrate was put on the surface with a knife, and then a cellophane adhesive tape was adhered to the cross cut portion to instantaneously peel off. The degree of peeling of the coating film at that time was evaluated according to the following criteria. ：: No peeling of the coating film is observed. Δ: Slight peeling of the coating film is observed. ×: Peeling of the coating film is considerably observed.

Water resistance: The coated plate was placed in a 40 ° C.
After immersion for one day, the coated plate was taken out, and the coating film having no abnormality such as gloss or blister was indicated by (○), and the one having abnormality such as gloss or blister was indicated by (x).

Chipping resistance: Gravelometer (manufactured by Q Panel Co., Ltd.) was used as a tester, and 500 g of No. 7 crushed stone was cooled to -20.degree. And the peeling state of the coating film was visually observed and evaluated according to the following criteria. ：: Almost no peeling of the coating film around the wound △: Some peeling of the coating film around the scratch ×: Remarkable peeling of the coating film around the wound

[0118]

[Table 5]

[0119]

[Table 6]

[0120]

According to the production method of the present invention, soft gelled polymer fine particles can be produced easily and without any problem on global environmental protection, and water as a solvent at the time of synthesis can be easily removed. it can.

The gelled polymer fine particles obtained by the production method of the present invention have a low glass transition temperature polymer inside the polymer fine particles and a large glass transition temperature polymer outside the polymer fine particles. By blending it in the composition, it acts as a flow regulator capable of achieving both smoothness and sagging resistance of the coated surface, and can improve chipping resistance.

Claims (8)

[Claims] 1. A polyfunctional monomer having at least two polymerizable unsaturated groups in a molecule, and (b) another polymerizable unsaturated monomer other than the polyfunctional monomer (a),
A method for producing gelled polymer fine particles, which comprises subjecting a monomer mixture consisting of the above to emulsion polymerization in the presence of a reactive emulsifier having an allyl group in the molecule, comprising a part of the polyfunctional monomer (a) and another polymerizable monomer. After emulsion polymerization of the following first monomer mixture comprising a part of the saturated monomer (b), the remaining amount of the polyfunctional monomer (a) and the remaining amount of the other polymerizable unsaturated monomer (b) are contained in the reaction system. A method for producing gelled polymer fine particles, comprising adding the following second monomer mixture comprising the following and conducting emulsion polymerization. A second monomer mixture, a polymer formed from the second monomer mixture , wherein the glass transition temperature of the polymer formed from the first monomer mixture first monomer mixture is in the range of −50 to 0 ° C. The glass transition temperature is in the range of 20-150C. 2. The method according to claim 1, wherein n-butyl acrylate is contained in an amount of 50 parts by weight or more based on 100 parts by weight of the first monomer mixture. 3. The process according to claim 1, wherein a water-soluble azoamide compound is used as a polymerization initiator in the emulsion polymerization for obtaining a gelled polymer fine particle dispersion. 4. An amount of the reactive emulsifier having an allyl group is 0.1 to 100 parts by weight of the total of the monomers (a) and (b).
The production method according to any one of claims 1 to 3, wherein the amount is in the range of 1 to 30 parts by weight. 5. The polymerization rate of the first monomer mixture is 80%.
The method according to any one of claims 1 to 4, wherein the second monomer mixture is added to the reaction system at the time when the above occurs, and polymerization is performed. 6. An organic solvent dispersion of gelled polymer particles obtained by dispersing gelled polymer particles obtained by the production method according to claim 1 in an organic solvent. 7. The method according to claim 1, wherein (A) the following film-forming binder resin (B) is stably dispersed without being dissolved in a diluent (C) solution. (B) a film-forming binder resin dissolved in the following diluent (C), and (C) a diluent dissolving the binder resin (B). A coating composition characterized by containing: 8. The coating composition according to claim 7, wherein the diluent (B) is a volatile organic solvent.