JP2001247820A - Coating material composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coating material composition which uses a cationic polymer as the binder component and excels in storage stability and can form lightweight coating films having high concealing properties. SOLUTION: This coating material composition comprises [1] particles of a cationic hollow crosslinked polymer having a zeta potential, measured in an aqueous medium having a pH of 2-9, in the range of +5 to +100 mV and [2] a film-forming cationic polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cationic hollow crosslinked polymer particle and a film-forming cationic polymer,
The present invention relates to a coating composition having excellent storage stability and capable of forming a light-weight and highly concealable coating film.

[0002]

2. Description of the Related Art Cationic polymers are used, for example, as binder resins for top coats of coatings based on paints based on anionic resins such as acrylic paints commonly used as interior and exterior paints for buildings. Used
It has characteristic characteristics as a resin for paint, such as forming a coating film having excellent adhesion and forming a tough cured film with a resin having an epoxy group. However, since the surface of titanium oxide, calcium carbonate, etc. used as pigments of general paints is anionic, a drawback that a cationic resin is used as a binder resin and paints containing these pigments have poor storage stability. Had.

[0003] On the other hand, hollow resin particles are used as a pigment that is effective in reducing the weight and has a high concealing property. As in the case where pigments such as titanium and calcium carbonate are blended, the storage stability of the paint is inferior. In addition, conventional hollow resin particles are dissolved in plasticizers and organic solvents commonly used in paint formulation,
Because of the disadvantage of melting during heating and drying, paints using hollow resin particles as pigments have been used only in very limited fields.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a coating composition which uses a cationic polymer as a binder component, has excellent storage stability, and can form a light-weight and highly concealable coating film. Is to do.

[0005]

According to the present invention, the above-mentioned object is achieved by providing a coating composition having the following constitution. 1. [1] It comprises a cationic hollow crosslinked polymer particle having a zeta potential measured in an aqueous medium of pH 2 to 9 in the range of +5 to +100 mV, and [2] a film-forming cationic polymer. Paint composition. 2. The cationic hollow crosslinked polymer particles are composed of 5 to 90% by weight of a structural unit derived from a crosslinkable monomer and 9 structural units derived from another monomer copolymerizable with the crosslinkable monomer.
5 to 10% by weight (the total amount of both is 100% by weight
The coating composition according to the above 1, wherein the coating composition comprises: 3. The cationic hollow crosslinked polymer particles are (1) 1 to 100% by weight of a crosslinkable monomer, (b) 0 to 15% by weight of a cationic monomer, and (c) copolymerizable using a radical polymerization initiator. 0-99% by weight of a non-crosslinkable and non-ionic monomer (total weight of the monomers is 100% by weight) is polymerized in the presence of polymer particles swellable on at least one of these monomers And (2) the polymer particles are (b) 0 to 30% by weight of a cationic monomer and (d) copolymerizable with the cationic monomer using a radical polymerization initiator. It is a polymer particle obtained by polymerizing 70 to 100% by weight of ionic monomer (the total weight of the monomer is 100% by weight), and (3) the above (1) and (2) The one or coating composition according to 2, characterized in that one or both of the radical polymerization initiator that is a radical initiator having a cationic group.

[0006] The cationic hollow crosslinked polymer particles contained in the coating composition of the present invention maintain cationicity in a wide pH range and have solvent resistance and heat resistance based on the crosslinked structure. The coating composition of the present invention using a forming cationic polymer as a binder component has excellent storage stability, can form a light-weight, highly concealable coating film, and can be used in a wide range of fields.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the coating composition of the present invention will be described in more detail. First, the components constituting the coating composition will be described.

[Cationic Hollow Crosslinked Polymer Particles] Cationic hollow crosslinked polymer particles (hereinafter simply referred to as “hollow crosslinked particles”)
Has a zeta potential of +5 to +100 mV, preferably +10 to +6, measured in an aqueous medium having a pH of 2 to 9.
It is in the range of 0 mV. In a preferred embodiment, the hollow crosslinked particles have a volume hollow ratio of preferably 1 to 80%, more preferably 3 to 40%, and an average particle diameter of preferably 0.03 to 10 µm, more preferably 0.1 to 10%. The particles are in the range of 1-5 μm.

The zeta potential is an index indicating the ionicity of the particles, and the fact that the zeta potential of the hollow crosslinked particles of the present invention is in the above range indicates that the particles have cationicity in a wide range of acidic to alkaline environments. ing. That is, the coating composition does not agglomerate with the film-forming cationic polymer as a binder component even under a wide range of acidic to alkaline atmospheres, and the coating composition has excellent storage stability. The measurement of the zeta potential of the hollow crosslinked particles is performed by the following method. (Measurement method of zeta potential) The aqueous dispersion of particles was diluted with a 0.1N aqueous potassium chloride solution so that the particle solid content concentration was 0.1% by weight, and this was diluted with hydrochloric acid or potassium hydroxide to pH 2,6. , 9 and the zeta potential at each pH is measured with a laser Doppler zeta potential meter.

The volume hollow ratio is a volume ratio of pores to particles. When the volume hollow ratio is less than 1%, it does not substantially function as hollow crosslinked particles. Also. When the volume hollow ratio exceeds 80%, the strength decreases, which is not preferable. In the present invention, the measurement of the volume hollow ratio is performed by the following method. (Measurement method of volume hollow ratio) An aqueous dispersion of particles was diluted with distilled water so that the particle solid content concentration was 0.1% by weight, and this was dropped on a copper mesh provided with a collodion film and dried.
The particles are photographed with a transmission electron microscope, the inner diameter and the outer diameter of 100 hollow crosslinked particles are measured from the obtained photograph, and the cube of the ratio of the obtained average inner diameter to the average outer diameter is defined as the volume hollow ratio. .

As described above, the average particle diameter of the hollow crosslinked particles is preferably in the range of 0.03 to 10 μm, and is in the form of fine particles. When the particle size is in this range, favorable results can be obtained in terms of dispersibility in a coating solvent, coating film strength, and coating stability. Hollow crosslinked particles having an average particle size of less than 0.03 μm are difficult to produce, while the average particle size is 10
If it exceeds μm, the coating becomes unstable, which is not preferable. In the present invention, the average particle size is measured by the following method (measurement method of average particle size) An aqueous dispersion of particles is appropriately diluted with distilled water, and averaged using a dynamic light scattering particle size analyzer. Measure the particle size.

The cationic hollow crosslinked polymer particles contained in the coating composition of the present invention maintain cationicity even in an acidic to alkaline atmosphere and have sufficient strength and dispersibility. Therefore, it is excellent as a white pigment of a paint. The hollow crosslinked particles preferably further have the following properties. First, it is preferable to have solvent resistance to organic solvents such as toluene and alcohol. By having solvent resistance, there is an advantage that the shape of particles is maintained when blended into a paint. Specifically, 2
It is preferable that the content of the component dissolved in toluene at 5 ° C. is 10% or less. Further, it is preferable to have heat resistance. By having heat resistance, there is an advantage that the shape of the particles is maintained even in a high-temperature drying step. In particular,
24% 10% decrease temperature measured by thermobalance (TGA)
The temperature is preferably 0 ° C. or higher. Such solvent resistance and heat resistance can be developed by appropriately selecting the monomer species.

Examples of the polymer constituting the cationic hollow crosslinked polymer particles include acrylic resins, polystyrene resins, polyolefin resins, polyester resins, polycarbonate resins, polyurethane resins, phenol resins, epoxy resins, ionomers. Thermoplastic resins or thermosetting resins such as resin, vinyl chloride resin, fluororesin, and butadiene resin are exemplified. It is essential that at least a part of the polymer constituting the hollow crosslinked particles has a cationic group. In the present invention, the cationic group includes a group capable of forming a cation by bonding to a proton such as an amino group and a group in which the group reacts with an acid to form a salt and form a cation portion of the salt. . Specific examples of the cationic group include a primary amino group, a secondary amino group, and a tertiary amino group; a quaternary amino group, a secondary imino group, a tertiary imino group, and a quaternary imino group; an amidino group and an imidino group of each grade. And a hydrazino group; and a cyclic group containing a nitrogen atom such as a pyridyl group.

The concentration of the cationic group in the hollow crosslinked particles is preferably 0.05 to 300 mmol / 100 g particles, more preferably 1 to 100 mmol / 100 g particles.

The hollow crosslinked particles preferably comprise a structural unit derived from a crosslinkable monomer and a structural unit derived from another monomer copolymerizable with the crosslinkable monomer. The proportion of the structural unit derived from the crosslinkable monomer is preferably 5 to 90% by weight, more preferably 1 to 90% by weight.
0 to 60% by weight, particularly preferably 15 to 50% by weight, and the proportion of structural units derived from other monomers is preferably 95 to 10% by weight, more preferably 90 to 4% by weight.
It is 0% by weight, particularly preferably 85 to 50% by weight (where the total amount of both structural units is 100% by weight). The existence of the structure derived from the crosslinkable monomer in the hollow crosslinked particles in the above range as described above means that the hollow crosslinked particles have a large number of crosslinked structures, and the strength and heat resistance of the hollow crosslinked particles are improved. , With favorable results. Here, the ratio of the structural unit derived from the crosslinkable monomer to the structural unit derived from another monomer is a value as an average of all the polymers constituting the hollow crosslinked particles.
For example, in the following production methods (I) to (IV), which are preferred methods for obtaining hollow crosslinked particles, polymerization is carried out in the presence of a polymer of swellable polymer particles and the swellable polymer particles. The above ratio is calculated as an average value with the polymer.

The method for producing the cationic hollow crosslinked polymer particles of the present invention is not particularly limited, but the following production methods (I) to (IV) are preferred.

Hereinafter, these production methods (I) to (IV) will be described. First, the monomers (a) to (d) used in the production methods (I) to (IV), the radical polymerization initiator having a cationic group, and the like will be described in detail. <Monomer> (a) Crosslinkable monomer divinylbenzene, divinylbiphenyl, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, propylene glycol Di (meth) acrylate, dipropylene glycol di (meth)
Acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) ) Acrylate, 2,2′-bis [4- (meth) acryloyloxypropoxyoxyphenyl] propane, 2,2′-bis [4
-(Meth) acryloyloxydiethoxyphenyl] propane, glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and other divinyl monomers, trivinyl monomers and tetravinyl monomers Is mentioned. Among them, divinylbenzene,
Preference is given to ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate. These can be used alone or in combination of two or more.

(B) Cationic monomer 2-dimethylaminoethyl (meth) acrylate, 2-
Aminoalkyl group-containing (meth) acrylates such as diethylaminoethyl (meth) acrylate, 2-dimethylaminopropyl (meth) acrylate, and 3-dimethylaminopropyl (meth) acrylate; and methylene chloride, dimethyl sulfate, and diethyl sulfate thereof. 4 by etc.
Grade salt; 2- (dimethylaminoethoxy) ethyl (meth)
Aminoalkoxyalkyl group-containing (meth) acrylates such as acrylate, 2- (diethylaminoethoxy) ethyl (meth) acrylate, and 3- (dimethylaminoethoxy) propyl (meth) acrylate; and methylene chloride, dimethyl sulfate, and sulfuric acid thereof. Quaternary salts with diethyl and the like; N- (2-dimethylaminoethyl) (meth) acrylamide, N- (2-diethylaminoethyl) (meth) acrylamide, N- (2-dimethylaminopropyl) (meth) acrylamide, N- N- such as (3-dimethylaminopropyl) (meth) acrylamide
Aminoalkyl group-containing (meth) acrylamides and quaternary salts thereof with methylene chloride, dimethyl sulfate, diethyl sulfate and the like can be mentioned. Among them, 2-dimethylaminoethyl (meth) acrylate, N- (2-dimethylaminoethyl) (meth) acrylamide, and quaternary salts thereof with methylene chloride are preferable. These can be used alone or in combination of two or more.

(C) Non-crosslinkable and nonionic monomer capable of being copolymerized Here, (c) the noncrosslinkable and nonionic monomer which can be copolymerized includes the above (a) a crosslinkable monomer or (b) a cation. Non-crosslinkable and nonionic monomers that can be copolymerized with any of the hydrophilic monomers. Examples of such a monomer include aromatic vinyl monomers such as styrene, α-methylstyrene, p-methylstyrene, and halogenated styrene; unsaturated nitriles such as acrylonitrile; methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, and butyl. Acrylate, butyl methacrylate, cyclohexyl methacrylate, 2
-Acrylates and methacrylates such as ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate; diolefins such as butadiene and isoprene; Carboxylic acid vinyl esters such as vinyl acetate; and vinylidene halides such as vinyl chloride and vinylidene chloride. Among them, styrene, α-methylstyrene, acrylonitrile, methyl methacrylate, butyl methacrylate, and 2-hydroxyethyl acrylate are preferred. These monomers are
One type may be used alone, or two or more types may be used in combination.

(D) Nonionic monomer copolymerizable with the above (b) cationic monomer This monomer is the same as the above (a) crosslinked except that it satisfies the condition that it can be copolymerized with the (b) cationic monomer. The same as the nonionic monomer and (c) the copolymerizable non-crosslinkable and nonionic monomer. Specific examples thereof include the monomers exemplified as (a) a crosslinkable monomer and (c) a copolymerizable non-crosslinkable and nonionic monomer, including preferable monomers. However, the crosslinkable monomer is used as needed within a range that does not impair the achievement of the object of the present invention. These monomers can be used alone or in combination of two or more.

<Radical polymerization initiator having a cationic group> In the radical polymerization initiator, a polymer obtained by radical polymerization using the radical polymerization initiator has a cationic group derived from the radical polymerization initiator at its terminal. Things. Preferred examples of the radical polymerization initiator having a cationic group include an azobis-type initiator having an amidino group, an imidino group or a pyridium group. Also, 1
Those having a 0-hour half-life temperature in the range of 40 to 95 ° C. are preferred because the polymerization can be carried out under mild conditions. Preferred specific examples of the radical polymerization initiator having a cationic group include the following.

2,2'-azobis (2-methyl-N-phenylpropionamidine) dihydrochloride (sold by Wako Pure Chemical Industries, Ltd. under the trade name VA-545) 2,2'-azobis [N- (4-chlorophenyl) -2
-Methylpropionamidine] dihydrochloride (sold by Wako Pure Chemical Industries, Ltd. under the trade name VA-546)-2,2'-azobis [N- (4-hydroxyphenyl)
-2-Methylpropionamidine] dihydrochloride (sold by Wako Pure Chemical Industries, Ltd. under the trade name VA-548). 2,2'-azobis [2-methyl-N- (phenylmethyl) -propionamidine] dihydrochloride. (Sold as VA-552 from Wako Pure Chemical Industries, Ltd.) 2,2'-azobis [2-methyl-N- (2-propenyl) propionamidine] dihydrochloride (from Wako Pure Chemical Industries, Ltd.)・ Sold as VA-553 (trade name) ・ 2,2′-azobis (2-methylpropionamidine)
Dihydrochloride (trade name V from Wako Pure Chemical Industries, Ltd.)
-2,2'-azobis [N- (2-hydroxyethyl)-
2-Methylpropionamidine] dihydrochloride (sold by Wako Pure Chemical Industries, Ltd. under the trade name VA-558). 2,2'-azobis [N- (2-carboxyethyl)-
2-Methylpropionamidine] hydrate (sold by Wako Pure Chemical Industries, Ltd. under the trade name VA-057)

2,2'-azobis [2-methyl- (5-
Methyl-2-imidazolin-2-yl) propane] dihydrochloride (trade name VA- from Wako Pure Chemical Industries, Ltd.)
2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride (sold by Wako Pure Chemical Industries, Ltd. under the trade name VA-044). Azobis [2- (4,5,6,7-tetrahydro-1H-1,3-diazepin-2-yl) propane] dihydrochloride (sold by Wako Pure Chemical Industries, Ltd. under the trade name VA-054) 2,2'-Azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride (sold by Wako Pure Chemical Industries, Ltd. under the trade name VA-058) -Azobis [2- (5-hydroxy-3,4,4
5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride (sold by Wako Pure Chemical Industries, Ltd. under the trade name VA-059) 2,2′-azobis {2- [1- (2-hydroxyethyl) ) -2-Imidazolin-2-yl] propane} dihydrochloride (trade name VA-0 from Wako Pure Chemical Industries, Ltd.)
2,2'-azobis [2- (2-imidazolin-2-yl) propane] (trade name VA- from Wako Pure Chemical Industries, Ltd.)
061) 2,2′-azobis (2-methylpropionamidine) dihydrochloride (V-50), 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] Hydrate (VA-057),
The use of 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride (VA-044) is preferred.

Next, the production methods (I) to (IV) for producing the cationic hollow crosslinked polymer particles will be described. <Production method (I)> In this method (I), (a) 1 to 99.99% by weight, preferably 5 to 8% by weight of a crosslinkable monomer is used.
0% by weight, more preferably 15 to 70% by weight, (b)
0.01 to 15% by weight, preferably 0.1 to 10% by weight, more preferably 0.5 to 5% by weight of a cationic monomer, and (c) a copolymerizable non-crosslinkable and nonionic monomer 0 to 0% 99.99% by weight, preferably 10-9
4.99% by weight, more preferably 25 to 84.5% by weight (the total weight of the monomers is 100% by weight) of polymer particles (hereinafter referred to as swellable) with respect to at least one of the monomers used for polymerization. (Hereinafter simply referred to as “swellable polymer particles”) to produce hollow crosslinked particles, preferably by polymerization in an aqueous medium.

In the above method, the mechanism by which the hollow crosslinked particles are formed is not necessarily clear, but, for example, by coexisting a swellable polymer particle in addition to a polymerizable monomer containing a crosslinkable monomer in an aqueous medium,
During polymerization, the volume change occurs when the monomer that has infiltrated into the swellable polymer particles is polymerized and converted into a polymer, and as a result, pores are formed inside the crosslinked polymer, resulting in a hollow body formed by the crosslinked polymer. Is thought to be formed. On the other hand, when no swellable polymer particles are present, no pores are formed. This presumption is considered to apply not only to the manufacturing method (I) but also to other manufacturing methods (II) to (IV).

In the present method, if the amount of the crosslinkable monomer (a) used is too small, less than 1% by weight, the strength of the particles during polymerization becomes insufficient and the whole particles shrink, and the inside of the particles is reduced. Insufficiency of strain due to polymerization shrinkage prevents inner pores from being formed,
Alternatively, even if polymer particles having inner pores are formed, problems such as a decrease in strength occur. If the amount of (a) the crosslinkable monomer used exceeds 99.99% by weight and is excessive, the amount of (b) the cationic monomer used is reduced,
The cationic properties of the hollow crosslinked particles obtained are low. The amount of (a) the crosslinkable monomer used is a pure product equivalent, excluding the inert solvent and the monofunctional non-crosslinkable monomer component contained in the commercially available crosslinkable monomer material. (B) If the amount of the cationic monomer used is too small as less than 0.01% by weight, the resulting hollow crosslinked particles will have reduced cationicity, and will not satisfy the above-mentioned conditions regarding the zeta potential. On the other hand, if the amount of the cationic monomer used exceeds 15% by weight and is excessive, it is not preferable because agglomerates are formed during polymerization. (C) The copolymerizable non-crosslinkable and nonionic monomer is a monomer optionally used for changing hydrophilicity or improving heat resistance as desired. If the amount used exceeds 98.9% by weight,
The amount of (a) the crosslinkable monomer or (b) the cationic monomer used is reduced, and the strength and cationicity of the obtained polymer particles are reduced.

In the present invention, "the monomer can swell"
The term means the case where the polymer particles can absorb the monomer, and includes the case where the monomer can dissolve the polymer particle.

As the polymer constituting the swellable polymer particles, at least one selected from styrene homopolymers and styrene copolymers is preferably used. Examples of the styrene copolymer include a copolymer of styrene and at least one selected from acrylates, methacrylates, and acrylonitrile. Among these, a styrene homopolymer or a styrene copolymer containing 50% by weight or more of a styrene component is particularly preferable.

The amount of the swellable polymer particles used is 100% by weight of the total amount of (a) a crosslinkable monomer, (b) a cationic monomer, and (c) a copolymerizable non-crosslinkable and nonionic monomer. 1 to 100 parts by weight per part,
Preferably it is 2 to 50 parts by weight, more preferably 5 to 20 parts by weight. If the amount of the swellable polymer particles is less than 1 part by weight, the volume hollow ratio is reduced, while if the amount of the swellable polymer particles is more than 100 parts by weight, the formation of pores tends to be suppressed. Is generated.

As a method of carrying out the polymerization by allowing the swellable polymer particles to be present in the aqueous dispersion, the swellable polymer particles are dispersed in the aqueous medium, and the above-mentioned (a), (b) and (c) are added thereto. The method of polymerizing after swelling any of the polymerizable monomers of the above) can be preferably employed. In this case, it is highly preferred that the swellable polymer particles function as seed polymer particles and that any of the polymerizable monomers swell well. For that purpose, the polymer constituting the swellable polymer particles preferably has a small molecular weight,
For example, the number average molecular weight is 20,000 or less, preferably 10,000 or less, and more preferably 700 to 7000.

Here, the number average molecular weight is a value obtained by dissolving the swellable polymer particles in a good solvent thereof and measuring the obtained solution by gel permeation chromatography (GPC). When the number average molecular weight of the swellable polymer particles is greater than 20,000, the amount of the monomer that does not swell in the swellable polymer particles increases, and this polymerizes separately from the swellable polymer particles in the aqueous dispersion, thereby resulting in polymer particles having pores. Not only will a large amount of fine particles not be formed be generated, but also the problem that the polymerization system will become unstable will occur.

The average particle diameter of the swellable polymer particles used as seed polymer particles is 30 to 8 times the average particle diameter (outer diameter) of the cationic hollow crosslinked polymer particles of the present invention.
It is preferably 0%. The particle size of the polymer particles having voids obtained by polymerization using the swellable polymer particles approximately matches the particle size when the swellable polymer particles swell the polymerizable monomer and enlarge. Therefore, by adjusting the particle size of the swellable polymer particles, the amount of the swellable polymer particles used relative to the polymerizable monomer, and the like, the particle size of the hollow crosslinked particles to be produced can be controlled. Specifically, in the production of polymer particles having pores, in order to obtain hollow crosslinked particles having a particle size of 0.06 to 0.6 μm having excellent whiteness and hiding power, 0.1% of swellable polymer particles is required. 03-0.4
A particle having a particle diameter of 0 μm may be used.

The method of preparing such swellable polymer particles is not particularly limited, and for example, a polymerization method such as emulsion polymerization or suspension polymerization using a relatively large amount of a chain transfer agent can be used.

The polymerization of the monomers (a) to (c) in the presence of the swellable polymer particles is preferably carried out in an aqueous medium by an emulsion polymerization method or a suspension polymerization method.

In the above polymerization, a surfactant used in ordinary polymerization, or an organic or inorganic suspension protective agent can be used. Generally, when producing hollow crosslinked particle polymer particles having an average particle size of less than 1 μm,
When mainly using a surfactant to produce hollow crosslinked particle polymer particles having a large average particle diameter of 1 μm or more,
Suspension protectants may be used primarily.

Examples of the surfactant include cationic surfactants such as alkylamines (salts), polyoxyethylene alkylamines (salts), quaternary alkylammonium salts, and alkylpyridinium salts; dodecyldimethylbetaine, alkylimidazo. Amphoteric surfactants such as rhinium betaine; polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, ethylene oxide addition derivative of alkylphenol formalin condensate, polyoxyethylene glycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid alkanolamide , Polyoxyethylene fatty acid amide, reactive emulsifier having polyoxyethylene as a hydrophilic group (“ADEKAREASORP NE-20” manufactured by Asahi Denka Kogyo, “Aqualon RN-2” manufactured by Daiichi Kogyo Seiyaku) Nonionic surfactants such as "); and combinations of these systems is preferably used. Anionic surfactants are not suitable for use in the present invention because they tend to form aggregates during polymerization.

Examples of the organic suspension protective agent include hydrophilic synthetic high molecular substances such as polyvinyl alcohol, polyvinylpyrrolidone and polyethylene glycol, natural hydrophilic high molecular substances such as gelatin and water-soluble starch, and carboxymethyl cellulose. Examples include hydrophilic semi-synthetic polymer substances. Further, as the inorganic suspension protective agent, for example, magnesium, barium, phosphates such as calcium, calcium carbonate, magnesium carbonate, zinc white,
Examples include aluminum oxide and aluminum hydroxide.

As the polymerization initiator, either an oil-soluble polymerization initiator or a water-soluble polymerization initiator can be used. When performing polymerization for producing hollow crosslinked particles having a particle diameter of 1 μm or less, it is preferable to use a water-soluble polymerization initiator, whereby monomer droplets having a large particle size that are not swollen by the hollow crosslinked particles are preferably used. Polymerization can be prevented. In the case of performing polymerization for producing hollow crosslinked particles having a particle size exceeding 1 μm, an oil-soluble polymerization initiator is used in order to prevent generation of polymer particles having no unnecessary pores. Is preferred.

Examples of the water-soluble polymerization initiator include persulfates, and redox initiators such as hydrogen peroxide-ferrous chloride and cumene hydroperoxide-sodium ascorbate. Examples of the oil-soluble polymerization initiator include benzoyl peroxide, lauroyl peroxide, t-butylperoxy-2-ethylhexanoate, azobisisobutyronitrile and the like. Further, the above-mentioned radical polymerization initiator having a cationic group can also be used.

Depending on the combination of the monomers (a), (b) and (c), the polymerization rate may be high. In this case, the polymerization is carried out using a large polymerization vessel, and all of the polymerization components are placed in the polymerization vessel. When a so-called batch polymerization method is used in which the polymerization is carried out, it is difficult to control the polymerization temperature, and there is a danger that the polymerization reaction will run away. Therefore, in order to avoid such danger, a so-called increment polymerization method, in which the monomer component is supplied to the polymerization vessel continuously or in a divided state during the polymerization in the state of an emulsion or in the form of an emulsion, may be employed. it can.

After the polymerization, the hollow crosslinked particles are separated from the aqueous dispersion and dried to obtain the cationic hollow crosslinked polymer particles of the present invention having pores therein.

According to the production method (I) of the present invention, for example, a hollow body having an average outer diameter (average particle diameter) of 0.03 to 10 μm and an inner diameter of 0.2 to 0.95 times the outer diameter is used. Thus, cationic hollow crosslinked polymer particles having a single void are obtained. This is the same for the production methods (II) to (IV).

Such a production method (I) is preferably used particularly for producing hollow crosslinked particles having a large amount of cationic groups.

<Production method (II)> In the production method (II),
Polymerization is carried out using a radical polymerization initiator having a cationic group to give the resulting hollow crosslinked particles cationicity. And (a) 1 to 100% by weight of the crosslinkable monomer, preferably 5 to 80% by weight, more preferably 15 to 70% by weight, and (b) 0 to 15% by weight of the cationic monomer, preferably 0 to 10% by weight And more preferably 0.1 to 10% by weight, and (c) 0 to 99% by weight, preferably 10 to 95% by weight, more preferably 20 to 84.9% by weight of a copolymerizable non-crosslinkable and nonionic monomer. % By weight (the total weight of the monomers is 100% by weight) in the presence of polymer particles swellable with respect to at least one of the monomers used in the polymerization. Almost the same as the production method (I) except that a radical polymerization initiator having a cationic group is used, and the amounts of the monomers (a), (b) and (c) used are slightly different. , Including a process for the preparation of swellable polymer particles, the polymerization process, operating, the conditions are applied that described in the production method (I).

In the production method (II), the polymerizable monomer may be only (a) a crosslinkable monomer, or (b) a cationic monomer and / or (c) a copolymerizable non-crosslinkable and nonionic monomer. You may. (A) when the amount of the crosslinkable monomer used is less than 1% by weight, and (b) when the amount of the cationic monomer used is more than 15% by weight, and (c) non-crosslinkable copolymerizable. Undesirable phenomena that occur when the amount of the ionic and nonionic monomer used exceeds 99% by weight and the like are the same as those described in the production method (I).

The amount of the radical polymerization initiator having a cationic group to be used is preferably 0.1 to 10 parts by weight per 100 parts by weight of the total monomers used for the polymerization.
More preferably, it is 0.5 to 5 parts by weight. The amount used is 0.
If the amount is less than 1 part by weight, the cationic properties of the obtained hollow crosslinked particles decrease, and if it exceeds 10 parts by weight, polymerization becomes unstable, which is not preferable.

The production method (II) is characterized in that hollow crosslinked particles having few aggregates can be obtained.

<Production method (III)>
This is a method for obtaining the cationic hollow crosslinked polymer particles of the present invention by making the swellable polymer particles in the production method (I) cationic. The swellable polymer particles are
(B) 0.01 to 30% by weight, preferably 0.1 to 15% by weight, more preferably 1 to 10% by weight of cationic monomer
%, And (d) 70 to 99.99% by weight, preferably 85 to 99.9% by weight, more preferably 90 to 9% by weight of a nonionic monomer copolymerizable with the cationic monomer.
It is obtained by polymerizing 99% by weight (the total weight of the monomers is 100% by weight). The swellable polymer particles include the following monomers (a), (b),
It can swell to any of (c). And, in the presence of the cationic swellable polymer particles,
(A) 1 to 100% by weight, preferably 5% by weight of a crosslinkable monomer
To 80% by weight, more preferably 15 to 70% by weight,
(B) 0 to 15% by weight, preferably 0 to 10% by weight, more preferably 0.1 to 10% by weight of a cationic monomer, and (c) 0 to 95% of a copolymerizable non-crosslinkable and nonionic monomer. % By weight, preferably from 10 to 90% by weight, more preferably from 20 to 84.9% by weight (the total amount of monomers is 100% by weight). Therefore, the production method (III) uses the above-mentioned swellable polymer particles and the production method (I
It is almost the same as the production method (I) except that the amount of the polymerization monomers (a), (b) and (c) used is slightly different from that in the case of I). What has been said in method (I) applies.

In preparing the cationic swellable polymer particles by polymerization, the method for preparing swellable polymer particles described in the production method (I) can be applied. The amount of the monomer (b) used for preparing the cationic swellable polymer particles is less than 0.01% by weight (the amount of the monomer (d) is 99.99).
In the case where the amount of the monomer (b) exceeds (by weight), the cationic hollow crosslinked polymer particles of the present invention obtained have a reduced cationicity, and the amount of the monomer (b) exceeds 30% by weight (excess of the monomer (d)). If the amount is too small (less than 70% by weight), the polymerization becomes unstable, which is not preferable.

The polymerization of the production method (III) is carried out according to the production method (I
As in the case of I), the polymerization monomer may be only (a) a crosslinking monomer, and (b) a cationic monomer and / or
Alternatively, (c) a copolymerizable non-crosslinkable and nonionic monomer may be used in combination. (A) when the amount of the crosslinkable monomer used is less than 1% by weight, and (b) when the amount of the cationic monomer used is more than 15% by weight, and (c) non-crosslinkable copolymerizable. Undesirable phenomena that occur when the amount of the ionic and nonionic monomer used exceeds 95% by weight are the same as those described in the production method (I).

Such a production method (III) is preferably used when producing hollow crosslinked particles in which the amount of cationic groups and the amount of aggregates are balanced.

<Production method (IV)>
(A) When the swellable polymer particles in the production method (I) are prepared by polymerization, a cationic polymerization is carried out by using a radical polymerization initiator having a cationic group and making the swellable polymer particles cationic. A method for obtaining particles, (b) a monomer (a) using a radical polymerization initiator having a cationic group similarly to the production method (II),
(B) The method of carrying out the polymerization of (c) to make the obtained hollow crosslinked particles cationic, or (c) the method of (a) and (b) above to make the hollow crosslinked particles cationic. How to Especially, the method (c) is preferable.

The swellable polymer particles are prepared by using a radical polymerization initiator to prepare (b) a cationic monomer in an amount of 0 to 30% by weight, preferably 0 to 15% by weight, and more preferably 0.1 to 15% by weight.
1 to 10% by weight, and (d) 70 to 100% by weight of a nonionic monomer copolymerizable with the cationic monomer,
Preferably 85 to 100% by weight, more preferably 90%
-99.9% by weight (Total weight of monomer is 100% by weight
Is prepared by polymerizing The above (a)
In the methods (c) and (c), a radical initiator having a cationic group is used as the radical polymerization initiator, and the prepared swellable polymer particles are cationic. The swellable polymer particles comprise a monomer (a) used for polymerization,
Swellable in at least one of (b) and (c). Then, in the presence of the swellable polymer particles, as in the production method (III), (a) 1 to 100% by weight, preferably 5 to 80% by weight, more preferably 15 to 70% by weight of the crosslinkable monomer, ( b) 0 to 15% by weight of a cationic monomer, preferably 0 to 10% by weight, more preferably 0.1 to 10% by weight, and (c) 0 to 99% by weight of a copolymerizable non-crosslinkable and nonionic monomer. %,
Preferably 10 to 95% by weight, more preferably 20 to 95% by weight.
84.9% by weight (the total weight of the monomers is 100% by weight) is polymerized using a radical initiator to obtain hollow crosslinked particles. In the above methods (b) and (c), a radical initiator having a cationic group is used as the radical polymerization initiator. As described above, in the production method (IV), the radical polymerization initiator having a cationic group may be used when preparing the swellable polymer particles, and the monomers (a), (b), and (c) are polymerized. Except that a radical polymerization initiator having a cationic group may be used in this case, and the use ratio of the monomers (b) and (d) for obtaining swellable polymer particles is slightly different, the production method (II
Almost the same as I). Thus, monomers (a),
As for the polymerization method, operation, conditions and the like of (b) and (c), those described in the production method (I) are applied.

When a radical polymerization initiator having a cationic group is used for preparing the swellable polymer particles, the amount of the radical polymerization initiator used is 0.1 to 10 parts by weight per 100 parts by weight of the total amount of the monomers (b) and (d). It is preferable to use one part by weight, more preferably 0.5 to 5 parts by weight. 0.1 used
If the amount is less than 10 parts by weight, the cationic property of the obtained hollow crosslinked particles is reduced. If the amount exceeds 10 parts by weight, the polymerization becomes unstable, which is not preferable. Monomers (a), (b),
When a radical polymerization initiator having a cationic group is used when polymerizing (c), it is preferably used in an amount of 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the total monomer. Department.

In preparing the swellable polymer particles by polymerization, a polymerization method (II
As in the case of I), the polymerization method for producing hollow crosslinked particles described in the production method (I) can be applied. In addition,
In preparation, a seed polymer may be used. When the amount of the monomer (b) used to prepare the cationic swellable polymer particles exceeds 30% by weight and is excessive (the amount of the monomer (d) is less than 70% by weight), The polymerization becomes unstable, which is not preferable.

The polymerization of the production method (IV) is carried out by the production method (II)
As in the case of I), the polymerization monomer may be only (a) a crosslinking monomer, and (b) a cationic monomer and / or
Alternatively, (c) a copolymerizable non-crosslinkable and nonionic monomer may be used in combination. (A) when the amount of the crosslinkable monomer used is less than 1% by weight, and (b) when the amount of the cationic monomer used is more than 15% by weight, and (c) non-crosslinkable copolymerizable. Undesirable phenomena that occur when the amount of the ionic and nonionic monomer used exceeds 99% by weight and the like are the same as those described in the production method (I). In the polymerization, it is preferable to use a radical polymerization initiator having a cationic group as the polymerization initiator in view of adjusting the zeta potential and stabilizing the polymerization within the scope of the present invention. in this case,
The amount of the radical polymerization initiator having a cationic group is as described above.

Such a production method (IV) is characterized in that hollow crosslinked particles having extremely few aggregates can be obtained.

The cationic hollow crosslinked polymer particles described above are contained in the coating composition (solid content excluding the solvent) of the present invention preferably in an amount of 0.1 to 80% by weight, more preferably 1 to 80% by weight.
６０60% by weight. If it is less than 0.1% by weight, the concealing property is insufficient, and if it exceeds 80% by weight, the coating film performance is poor.

[Cation-Forming Cationic Polymer] The film-forming cationic polymer (hereinafter simply referred to as “cationic polymer”) contained in the coating composition of the present invention contains a cationic group, and Applying a coating composition coating solution, drying,
There is no particular limitation as long as a film can be formed by heating as necessary. Here, the cation group has the same meaning as the cation group in the hollow crosslinked particles, and the same specific examples can be given.

Preferred cationic polymers include:
(A) a polymer obtained by copolymerizing the (b) cationic monomer used for producing the hollow crosslinked particles with the following monomers (I) to (VI); A polymer obtained by polymerizing the following monomers (I) to (VI) together with the above-mentioned (b) cationic monomer, if desired, using the above-mentioned radical polymerization initiator having a cationic group used for the production, No. (Monomer) (I) Alkyl ester of acrylic acid or methacrylic acid Methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl acrylate, methacrylic acid 2-hydroxyethyl and the like. (II) aromatic vinyl compound styrene, α-methylstyrene, vinyltoluene, t-
Butyl styrene and the like. (III) olefin ethylene, propylene, 1-butene, 1-hexene, 4
-Methyl-1-pentene, 1-octene and the like. (IV) Vinyl ester Vinyl acetate, vinyl propionate and the like. (V) Nitrile compounds Acrylonitrile, methacrylonitrile and the like. (VI) Polymerizable amide acrylamide, methacrylamide, diacetoneamide, N-methylolacrylamide and the like.

Among these, from the viewpoint of the weather resistance of the coating film, a polymer in which the alkyl ester component of acrylic acid or methacrylic acid accounts for 30% by weight or more, especially 50% by weight or more of all the constituent units is preferable as the cationic polymer. . The amount of the cationic group contained in the polymer is 0.05 to 100.
mmol / 100 g polymer, especially 0.2 to 50 mmol
It is preferably 1/100 g polymer. In addition, an acid group-containing monomer such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid may be slightly copolymerized with the cationic polymer as long as the cationic polymer is not damaged.

The cationic polymer is preferably prepared in a state of being finely dispersed in an aqueous medium. Preparation of the cationic polymer in a finely dispersed state in an aqueous medium can be performed by polymerizing the above monomer in an aqueous medium, by an emulsion polymerization method or a suspension polymerization method, but is not limited to this method. . The polymerization method, operation, conditions, and the like employed in carrying out the emulsion polymerization method or the suspension polymerization method for producing the above cationic polymer are the same as those described in the method (I) or the method (II) for producing hollow crosslinked particles. What has been said in the polymerization of a), (b) and (c) can be substantially applied.

The film-forming cationic polymer described above is used in the coating composition of the present invention (solid content excluding the solvent).
Preferably 5 to 99.9% by weight, more preferably 10 to 10% by weight.
99% by weight, particularly preferably 20 to 90% by weight. If it is less than 5% by weight, the coating film performance is insufficient, and if it exceeds 99.9% by weight, the concealing property is poor.

[Solvent] The coating composition of the present invention is preferably prepared as an aqueous dispersion dispersed in an aqueous solvent. The solid concentration of the aqueous dispersion is preferably from 5 to 70% by weight, more preferably from 10 to 60% by weight.

[Other Optional Ingredients] The coating composition of the present invention may contain a light stabilizer, an ultraviolet absorber, an organic solvent, a crosslinking agent, a water-soluble polymer (for example, a water-soluble polyester resin, Epoxy resin, water-soluble acrylic resin, polyvinyl alcohol, starch), defoamer, thickener, heat stabilizer, leveling agent, lubricant, antistatic agent, coloring agent, matting agent, pigment, fungicide, etc. An additive may be contained. These additives can be added to the coating composition of the present invention, if necessary, within a range not to impair the achievement of the object of the present invention.

[Preparation and application of coating composition] The coating composition of the present invention is prepared by mixing each component.
The preparation method used is not particularly limited, and a commonly used mixer or reactor such as a stirring tank, an autoclave, a flask, or a reactor can be used. The prepared coating composition is applied to the surface of the object. The thickness of the coating film to be formed is usually 10 to 1000 μm.
It is performed so that it may be in the range of. As a method of applying the coating composition, various known methods can be used. For example, application by a brush, hopper application, bar coater application, spin coating, spray application, curtain application, dip application, air knife application, blade application Coating, roll coating and the like can be mentioned. Thereafter, by drying at room temperature to 200 ° C., a coating film is formed on the surface of the object to be coated.

The coating composition of the present invention can form a light-weight and highly concealable film, and the binder component and hollow crosslinked particles constituting the formed film are cationic. Therefore, it can be used as an overcoat or undercoat of a paint film using an anionic polymer such as an acrylic paint as a binder component, which is generally used as a paint for interior and exterior of buildings, and a paint film having excellent adhesion. Is formed. Further, it can be used as a coating material for metal, paper, wood, concrete, plastic, ceramics, slate, and plaster.

[0068]

EXAMPLES The present invention will be specifically described below with reference to examples, but the scope of the present invention is not limited by the examples. In the following description, “parts” and “%” are based on weight unless otherwise specified.

Example 1 [Preparation of Aqueous Dispersion of Cationic Hollow Cross-Linked Polymer Particles] (1) Preparation of Seed Particle A In a temperature-controlled autoclave equipped with a stirrer, 600 parts of water, dodecyltrimethylammonium chloride 27% solution (Coatamine 24P manufactured by Kao Corporation) 5
Part, 2,2'-azobis (2-methylpropionamidine) dihydrochloride (V-50, manufactured by Wako Pure Chemical Industries, Ltd.)
Part, styrene 75 parts, acrylonitrile 10 parts, 2-
10 parts of ethylhexyl acrylate, 5 parts of a quaternary methylene chloride salt of dimethylaminopropylacrylamide, t
-Charge 15 parts of dodecyl mercaptan all at once, 70
The mixture was allowed to react at 3 ° C. for 3 hours, and after cooling, the coarse aggregate was filtered through a 300-mesh wire net to obtain an aqueous dispersion of seed particles A as swellable polymer particles.

(2) Production of Cationic Hollow Crosslinked Polymer Particles (A-1) by Polymerization 430 parts of water 10 parts of seed particles A (solid content) 2,2′-azobis (2-methylpropionamidine) dihydrochloride (V-50, manufactured by Wako Pure Chemical Industries, Ltd.) 1 part 59 parts methyl methacrylate 12 parts styrene 28 parts 28 parts divinylbenzene were charged all at once, reacted at 70 ° C. for 3 hours, cooled, and cooled.
The coarse aggregate was filtered through a 300-mesh wire net to obtain an aqueous dispersion of cationic hollow crosslinked polymer particles (A-1). With respect to the cationic hollow crosslinked polymer particles, the zeta potential, the volume hollow ratio, and the average particle diameter were measured by the methods described above. In addition, as a zeta potential measuring device, BROOKHAV
Using "Zetaplus" manufactured by ENINSTRUMENTS, and using "JEM-100SX" manufactured by JEOL Ltd. as a transmission electron microscope for measuring volumetric porosity,
"LPA-3000 / 310" manufactured by Otsuka Electronics Co., Ltd. as a dynamic light scattering particle size measuring instrument for measuring the average particle size.
0 "was used.

(3) Cationic hollow crosslinked polymer particles (A
Physical property measurement result of -1) Zeta potential: +40 mV at pH2, +36 m at pH6
V, +32 mV at pH 9, Volume hollow ratio; 30% Average particle diameter; 0.2 μm

[Preparation of Film-Forming Cationic Polymer Emulsion (B-1)] 60 parts of methyl methacrylate, n
13 parts of butyl methacrylate, 15 parts of 2-ethylhexyl acrylate, a mixture 10 of 9 parts of n-butyl acrylate and 13 parts of dimethylaminoethyl methacrylate
To 0 part, 3 parts of dodecylbenzylammonium chloride and 45 parts of ion-exchanged water were stirred with an azihomomixer to emulsify, and then 5% of the mixture was emulsified (emulsion A) (the rest was emulsified B). . 0.4 part of 2,2-azobis (2-aminodipropane) hydrochloride as an initiator was dissolved in 5 parts of ion-exchanged water. (This was designated as solution C.) Oxygen in a separable flask equipped with a stirrer and a nitrogen inlet tube was replaced with nitrogen, and 52 parts of ion-exchanged water was added.
The temperature was raised to 0 ° C., and at the same time as the emulsion A was added, 5% of the solution C was added to initiate the polymerization reaction. Stirring was continued during the polymerization reaction, and after 1 hour of polymerization, the remaining emulsion B and solution C were continuously and simultaneously dropped over 3.5 hours.
Thereafter, the temperature in the reaction vessel was raised to 80 ° C., and an aging reaction was performed for 1 hour. Then, the reaction vessel was cooled to terminate the reaction. Thereafter, diluted hydrochloric acid was added to obtain a cationic polymer emulsion (B-1). The obtained cationic polymer emulsion (B-1) had a solid content of 50.0% and a particle diameter of 0.1 to 0.3 μm.

[Preparation of Cationic Paint] 60 parts of an aqueous dispersion of the cationic hollow crosslinked polymer particles (A-1) as the particles, 100 parts of the cationic polymer emulsion as a solid content, and a plasticizer (CS-1 CS-1
2, substance name: 2,2,4-trimethyl-1,3-pentadiol monoisobutyrate) 10 parts was mixed with a mechanical stirrer to prepare a cationic paint. The paint was evaluated for storage stability and the concealment rate of a film formed from the paint by the following method. The results are shown in Table 1.

(Measurement and Evaluation Methods) (1) Stability of paint: 1000 g of paint was stirred, placed in a closed container, allowed to stand at 25 ° C. for 7 days, and 1 g of the upper liquid was collected.
It dried at 200 degreeC for 10 minutes, and measured the solid content from the weight change before and behind drying. When the difference from the previously measured solid content immediately after the preparation of the paint was less than 2%, it was evaluated as ○, and when it was 2% or more, as X. (2) Concealment ratio: 5 on Concealment ratio test paper (Japan Paint Inspection Association)
The film was applied to a thickness of 0.15 mm (0.127 mm), cured for 10 minutes at 120 ° C., and the Y value was measured with a color difference meter. did.

Comparative Example 1 [Preparation of Titanium Paste (A'-1)] 10 parts of a 27% solution of dodecyltrimethylammonium chloride (Coatamine 24P manufactured by Kao), 5 parts of polyoxyethylene nonylphenyl ether (Emulgen 920 manufactured by Kao), 10 parts of water was previously charged in a tank, and 60 parts of titanium oxide (R-780, manufactured by Ishihara Sangyo) was gradually added while stirring with a disper to prepare a titanium paste.

[Preparation of Cationic Coating] 60 parts of the above-mentioned titanium paste (A'-1) as titanium oxide, 100 parts of the above-mentioned cationic polymer emulsion as a solid content, and 10 parts of a plasticizer (CS-12 manufactured by Chisso) The parts were mixed with a mechanical stirrer to prepare a cationic paint.
This cationic paint was evaluated by the above method, and the results are shown in Table 1.

Comparative Example 2 [Preparation of Aqueous Dispersion of Hollow Non-Crosslinked Particles (A'-2)] Hollow non-crosslinked particles (A'-2) were prepared according to Example 1 of JP-A-10-27639. That is, 1 part of a monomer mixture (a) for forming a nucleus polymer (seed) composed of 60% of methyl methacrylate, 5% of butyl acrylate and 35% of methacrylic acid, and 0.005 of sodium emulsifier sodium dodecylbenzenesulfonate (DBS) And 0.8 parts of ion-exchanged water were mixed with stirring to prepare an emulsion (a). Separately, methyl methacrylate 70
%, Butyl acrylate 10% and methacrylic acid 20
% Of a core polymer-forming monomer mixture (b) comprising:
Emulsifier (DB) was prepared by mixing 0.05 part of emulsifier (DBS) and 8 parts of ion-exchanged water with stirring. Further, 25 parts of a monomer (c) for forming an intermediate layer polymer composed of 78% of methyl methacrylate, 16% of butyl acrylate and 6% of methacrylic acid, 0.1 part of emulsifier (DBS) and 35 parts of ion-exchanged water were stirred. An emulsion (c) was prepared by mixing below. Further, 37.5 parts of styrene,
Emulsifier (D) was prepared by mixing 0.3 part of emulsifier (DBS) and 16 parts of ion-exchanged water while stirring. 2.87 ion-exchanged water was added to a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a separating funnel.
Parts, a particle diameter of 35 nm, and a solid content concentration of 0.04 part (solid content conversion) of an acrylic seed type latex having a solid content of 12%.
The temperature was raised to 0 ° C. Then, potassium persulfate (0.17 parts of a 3% aqueous solution was added from a separating funnel, and the emulsion (a) was continuously added over 4 hours.
Polymerization was carried out for an hour to obtain a nuclear polymer emulsion. The polymerization conversion of the monomer mixture (a) was 99%. Next, 28 parts of ion-exchanged water and 1.7 parts of a 3% aqueous solution of potassium persulfate were added, and then the emulsion (b) was continuously added to the reactor over 3 hours. After the addition, the mixture was further polymerized for 2 hours to form a core layer polymer. The polymerization conversion of the monomer mixture (b) was 99%. Next, 240 parts of ion-exchanged water was added.
After adding 6.7 parts of a 3% aqueous solution of potassium persulfate,
Emulsion (c) was continuously added to the reactor over 4 hours. After the addition, the mixture was further polymerized for 2 hours to form an intermediate layer polymer. The polymerization conversion of the monomer mixture (c) is 99
%Met. Further, the temperature was raised to 85 ° C., and 6.7 parts of a 3% aqueous solution of potassium persulfate was added.
Was continuously added to the reactor over 1.5 hours. After the addition, the mixture was further polymerized for 1 hour to form an outer layer polymer. The polymerization conversion of the monomer mixture (d) was 99%. To the latex containing the polymer particles obtained above, 9 parts of a 10% aqueous solution of sodium hydroxide was dropped from a separating funnel, and then the base treatment was performed by continuing to heat at 85 ° C. for 30 minutes. At this stage, a part of the latex was collected, and the pH of the latex was measured at room temperature to find that it was 8.1. Next, N,
0.75 parts of N-dimethylaminomethyl methacrylate was added dropwise and reacted at 85 ° C. for 30 minutes to obtain an aqueous dispersion of hollow non-crosslinked particles (A′-2).

The resulting amphoteric hollow non-crosslinked polymer particles (A ′
Physical properties of -2) were as follows. Zeta potential: +21 mV at pH 2, +5 mV at pH 6,
-12 mV at pH 9 Volume hollow ratio; 30% Average particle diameter; 200 nm

[Preparation of Paint] The above hollow non-crosslinked particles (A ′)
-2) 60 parts of the aqueous dispersion as hollow non-crosslinked particles (A'-2), 100 parts of the above cationic polymer emulsion as a solid content, and a plasticizer (CS-12 manufactured by Chisso)
10 parts were mixed with a mechanical stirrer to prepare a paint. This coating material was evaluated by the above method, and the results are shown in Table 1.

[0080]

[Table 1]

From the results shown in Table 1, the paint of Example 1 is excellent in both paint stability and hiding power, but Comparative Example 1 using titanium oxide in place of the cationic hollow crosslinked polymer particles. Is poor in paint stability, and Comparative Example 2 using hollow non-crosslinked particles is poor in hiding.

[0082]

According to the coating composition of the present invention, the cationic hollow crosslinked polymer particles contained therein maintain cationicity in a wide pH range, and the cationic polymer is used as a binder component without impairing storage stability. Since it can be used, for example, when used as a top coat of a coated surface with an anionic base, a coating film having excellent adhesion to the base surface is formed, and has excellent coating performance, and the hollow particles are Since it has a crosslinked structure, a light-weight and highly concealable coating film can be formed.

Continuation of the front page F term (reference) 4J011 JA13 JB14 JB16 JB26 KA04 KA12 KA15 KB13 KB14 KB19 KB29 PA64 PA65 PA69 4J038 CA022 CB002 CC032 CD022 CD092 CG141 CG142 CG171 CH201 DA042 DB002 DD002 DE002 DG002 EA0126P08 AB02 AB02 AB02 AB02 AB02 AB02 AC03P AC04P AG04P AL03P AL04P AL05P AL08Q AL09P AL10P AL62R AL63R AL66R AL67R AM02P AM21Q AS02P AS03P BA02Q BA02R BA08R BA31Q BA32Q BC45R CA04 CA05 CA27 FA03 JA01

Claims (3)

[Claims] 1. A method comprising: [1] a cationic hollow crosslinked polymer particle having a zeta potential in a range of +5 to +100 mV measured in an aqueous medium having a pH of 2 to 9, and [2] a film-forming cationic polymer. A coating composition characterized by containing: 2. The cationic hollow crosslinked polymer particles have 5 to 90% by weight of a structural unit derived from a crosslinkable monomer and 95 to 10% by weight of a structural unit derived from another monomer copolymerizable with the crosslinkable monomer. (Where the total amount of both is 1
The coating composition according to claim 1, wherein the coating composition is 100% by weight. 3. The cationic hollow crosslinked polymer particle according to claim 1,
(1) Using a radical polymerization initiator, (a) 1 to 100% by weight of a crosslinkable monomer, and (b) cationic monomer 0 to 1
5% by weight, and (c) 0-99% by weight of the copolymerizable non-crosslinkable and nonionic monomers (total weight of monomers is 100% by weight), swelling with respect to at least one of these monomers Produced by polymerizing in the presence of possible polymer particles, and (2) the polymer particles are prepared by using a radical polymerization initiator to form (b) 0 to 30% by weight of a cationic monomer and (d) )
Polymer particles obtained by polymerizing 70 to 100% by weight of a nonionic monomer copolymerizable with the cationic monomer (the total amount of the monomers is 100% by weight);
3. The coating composition according to claim 1, wherein (3) one or both of the radical polymerization initiators in (1) and (2) are radical initiators having a cationic group.