KR19990007854A - Novel resin coating metal pigment and metal paint containing this pigment - Google Patents

Abstract

(A) at least one member selected from the group consisting of radical polymerizable unsaturated carboxylic acids, mono- and di-esters of phosphoric acid and phosphonic acid each having a radical polymerizable double bond, and a coupling agent having a radical-polymerizable double bond (B) using a monomer having three or more radical-polymerizable double bonds, and (C) a polymerization initiator, and treating the metal pigment with component (A), then at least one of (B) and (C) A resin-coated metal pigment produced according to a method characterized by polymerization by adding little by little, which is excellent in weatherability, chemical resistance, gloss and storage stability in an aqueous paint, and is a resin-coated metal metal which allows the formation of a metal finish. Pigments; And a metal coating containing the resin coating metal pigment.

Description

Novel resin coating metal pigment and metal paint containing this pigment

Metallic pigments have been used, for example, in pigments incorporated in metallic paints and printing inks or plastics to achieve a decorative effect when metallic feel is considered important.

However, coating films and resin molded articles obtained using conventional metal pigments have disadvantages such as insufficient chemical resistance (for example, acid resistance and alkali resistance) and water resistance, and inferior weather resistance. That is, as time passes, the drawing discolors and the gloss decreases. Therefore, there has been a great demand to obtain metal pigments having excellent storage stability as well as chemical resistance and weather resistance.

In order to solve this problem, a method of resin coating the metal pigment component has been proposed.

It is known that an aluminum paste can be dispersed in an organic solvent in which an ethylenically unsaturated monomer is dissolved, and heated in the presence of a polymerization initiator to obtain a resin coated aluminum paste having excellent chemical resistance (Japanese Patent Laid-Open No. 51-11818). . However, the resin coated aluminum paste obtained by this method has insufficient chemical resistance and cannot be put to practical use.

The aluminum paste is dispersed in an organic solvent, first adsorbed a radical-polymerizable unsaturated carboxylic acid or the like on the dispersed particles in the aluminum paste, and then dispersed into a polymer obtained from a monomer having three or more radical-polymerizable double bonds. A method has been proposed that includes covering the surface of granulated particles (Japanese Patent Application Laid-Open No. 1-49746). This method has a problem in that the gloss decreases because a large amount of coating resin monomer must be added to realize sufficient alkali resistance, so that the metallic feeling becomes very different.

Japanese Patent Laid-Open No. 7-3185 discloses a metal pigment containing a siloxane coating and a three-dimensional crosslinked synthetic resin coating covalently bonded to the siloxane coating. However, these metal pigments also have insufficient chemical resistance.

In addition, when used in an aqueous medium, the resin coated aluminum paste and the aluminum paste not coated with the resin react with water to produce hydrogen gas, thereby greatly reducing the metallic luster. When this paste is used for water-bone paints, measures such as the removal of gases are necessary.

In order to improve the uniformity and smoothness of the coating resin film, a method including coating with a radical-polymerizable monomer and oligomer has been proposed (Japanese Patent Laid-Open No. 64-40566). Also in the case of this method, when used as an aqueous paint, a large amount of hydrogen gas is generated as described above and the metallicity is greatly reduced, so that the coated product is inferior in storage stability.

[Initiation of invention]

The present inventors have studied diligently to solve the above problems in conventional metal pigments. As a result, the inventors of the present invention have found that mono-monomers of phosphoric acid or phosphoric acid (or phosphonic acid) with radically polymerizable unsaturated carboxylic acids, one or two radically polymerizable double bonds, Or a monomer and a polymerization initiator having at least three radically polymerizable double bonds in one molecule at a time and continuously supplemented or added to at least one species selected from the group consisting of diesters and a coupling agent having a radical polymerizable double bond. It was found that the object can be achieved by coating with a resin which is a copolymer obtained by continuous supplemental addition.

Specifically, the present invention includes the following aspects.

(1) (A) mono- or diesters of radically polymerizable unsaturated carboxylic acids and / or phosphoric acid (or phosphonic acids) having one or two radically polymerizable double bonds, and / or radical-polymerizable double At least one member selected from the group consisting of a coupling agent having a bond, (B) at least one monomer having at least three radical-polymerizable double bonds, and (C) a polymerization initiator, and (A) is first added to the metal The resin coating metal pigment which has a resin layer formed on the surface of a metal pigment by superposition | polymerization performed by processing a pigment and then gradually supplementing at least one of (B) and (C) little by little.

(2) A monomer having three radically polymerizable double bonds and a monomer having four or more radical polymerizable double bonds is used as (B) a monomer having three or more radical polymerizable double bonds, and the radical polymerizable double The resin coating metal pigment of 1st aspect whose ratio of the monomer which has four or more radically polymerizable double bonds with respect to the total amount of the monomer which has three or more bonds is 10%-60%.

(3) The resin-coated metal pigment according to the first or second aspect, wherein at least one of the at least one of the above components (B) and (C) is supplemented and added for at least 20% of the total polymerization time.

(4) The resin-coated metal pigment according to any one of the first to third aspects, wherein the molecular weight is 30 or more and 200 or less per one functional group of the monomer having four or more radical-polymerizable double bonds.

(5) The resin coating metal pigment as described in any side of the 1st-4th side which has alkali resistance of 2.0 or less.

(6) Metal coating material containing the resin coating metal pigment in any one of 1st-5th aspect.

(7) (A) monopolymers or diesters of radically polymerizable unsaturated carboxylic acids and / or phosphoric acid (or phosphonic acids) having one or two radically polymerizable double bonds, and / or radically polymerizable doublets At least one member selected from the group consisting of a coupling agent having a bond, (B) at least one monomer having at least three radical-polymerizable double bonds, and (C) a polymerization initiator, and (A) is first added to the metal The method of manufacturing the resin coating metal pigment which has a resin layer formed on the surface of a metal pigment by superposition | polymerization by carrying out continuous supplemental addition of at least one of (B) and (C) little by little after processing a pigment.

The present invention relates to novel resin coated metal pigments. More specifically, the present invention relates to a resin coating metal pigment which provides a metal coating film excellent in chemical resistance, gloss and weather resistance when used as a coating pigment and excellent in storage stability in an aqueous coating. Moreover, this invention relates to the novel metal coating material containing the said resin coating metal pigment, resin for coating materials, and diluent. More particularly, it relates to a coating which provides a metal coating film excellent in chemical resistance, gloss and weather resistance, and has very good storage stability.

The resin coated metal pigment according to the present invention has better chemical resistance than before, retains the gloss of the metal pigment, and has excellent storage stability.

Metal pigments used in the present invention include aluminum, copper, zinc, iron, nickel, and / or alloys thereof. Preferred example of the metal pigment is aluminum. The form of a metal pigment is granules, such as a flake shape, a spherical shape, and a needle shape. Preferred particle sizes of the metal pigments vary depending on the intended use. The average particle size of the metal pigment is preferably about 1 to 100 mu in the paint or printing ink, and preferably about 1 to 200 mu when incorporated into the plastic. However, the average particle size of the metal pigment is not particularly limited to the values in the above range.

Radical-polymerizable unsaturated carboxylic acids used in the present invention include acrylic acid, methacrylic acid, itaconic acid, fumaric acid and the like. They are used alone or in combination. The amount of radical-polymerizable unsaturated carboxylic acid (s) used varies depending on the type and properties of the metal pigment, especially the surface area, but is usually 0.1 to 10 parts by weight, preferably 0.1 to 5.0 parts by weight, based on the weight part of the metal pigment. to be. If the amount is less than 0.01 part by weight, the effects of the present invention are not satisfactorily achieved, that is, satisfactory chemical resistance (eg alkali resistance and acid resistance) cannot be achieved. In addition, when the monomer (s) having three or more polymerizable double bonds are polymerized on the surface of the metal pigment, the polymerization system is gelatinized and in some cases, stirring is impossible. When the amount is more than 10 parts by weight, effects such as chemical resistance are not improved.

As the phosphoric acid (or phosphonic acid) ester (s) having one or two radical-polymerizable double bonds used in the present invention, phosphoric acid (or phosphonic acid) monoesters and phosphoric acid (or phosphonic acid) diesters can be used. . Specific examples thereof include 2-methacryloyloxyethyl phosphate, di-2-methacryloyloxyethyl phosphate, tri-2-methacryloyloxyethyl phosphate, 2-acryloyloxyethyl phosphate, di- 2-acryloyloxyethyl phosphate, tri-2-acryloyloxyethyl phosphate, diphenyl-2-acryloyloxyethyl phosphate, dibutyl-2-acryloyloxyethyl phosphate, dioctyl-2-acrylic Royloxyethyl phosphate, 2-methacryloyloxypropyl phosphate, bis (2-chloroethyl) vinyl phosphate, and diallylbutyl phosphonosuccinate. These can be used individually or in mixture.

The term phosphate ester (s) is then used to include phosphonic acid ester (s) for simplicity.

Of the phosphate esters having one or two radical-polymerizable double bonds, phosphoric acid monoesters are preferred. The reason is estimated as follows: The phosphate monoester is more strongly fixed on the surface of the aluminum particles because its phosphate group has two OH groups. Preferred examples of phosphoric acid monoesters are methacryloyloxy groups or acryloyloxy groups such as 2-methacryloyloxyethyl phosphate and 2-acryloyloxyethyl phosphate and the like.

The amount of the phosphate ester (s) having one or two radical-polymerizable double bonds varies depending on the type and properties of the metal pigment, in particular the surface area, but is usually 0.01 to 30 parts by weight, preferably 100 parts by weight of the metal pigment. Preferably from 0.1 to 20 parts by weight. When the amount is less than 0.01 part by weight, the effects of the present invention are not satisfactory, that is, it is not possible to achieve satisfactory chemical resistance such as alkali resistance. When the amount of use is more than 20 parts by weight, improvement of the effect cannot be expected.

As the coupling agent (s) having a radical-polymerizable double bond used in the present invention, a silane coupling agent, a titanate type coupling agent and an aluminum-containing coupling agent can be exemplified.

The silane coupling agent includes γ-methacryloyloxypropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (β-methoxyethoxy) silane, and the like. .

Titanate type coupling agents include isopropylisostearoyldiacryl titanate and the like.

Aluminum-containing coupling agents include acetoalcoholaluminum diisopropylate, zirco-aluminate and the like.

The amount of the coupling agent (s) having a radical-polymerizable double bond varies depending on the kind and properties of the metal pigment, especially the surface area, but is usually 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight based on 100 parts by weight. to be. If the amount is less than 0.01 part by weight, the effects of the present invention are not satisfactory, that is, satisfactory chemical resistance such as satisfactory alkali resistance cannot be achieved. When the amount of use is more than 20 parts by weight, improvement of the effect cannot be expected.

Generally, when treating a metal pigment, it is treated in an inert solvent to prevent the reaction of water and the metal pigment itself.

Since radical-polymerizable unsaturated carboxylic acids and / or phosphoric acid mono or diesters having one or two radical-polymerizable double bonds are generally very soluble in inert solvents, their uniform dispersion is relatively It is easy. Therefore, they are preferable because they are unlikely to lower chemical resistance and storage stability in water-based paints.

As monomer (s) having three or more radical-polymerizable double bonds used in the present invention, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, tetramethylolmethane tetraacrylate, tetramethylolpropane tetra Acrylate, di-trimethylolpropane tetraacrylate, di-trimethylolpropane hexaacrylate, pentaerythritol tetraacrylate, di-pentaerythritol hexaacrylate, and the like. They are used alone or in combination.

Preferred examples of monomers having four or more radical-polymerizable double bonds are di-trimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, di-pentaerythritol hexaacrylate, and the like among the compounds exemplified above.

The total amount of the monomer (s) having three or more radical-polymerizable double bonds of the present invention is 2 to 50 parts by weight, preferably 3 to 40 parts by weight, based on 100 parts by weight of the metal component of the metallic pigment. If the total amount is less than 2 parts by weight, the effect of the present invention, that is, the chemical resistance is reduced. If the total amount is more than 50 parts by weight, no improvement of the effect can be expected, and the basic properties (such as luster and gloss) as the metal paint are lowered. Therefore, the obtained metal paint is difficult to be put into practical use.

When the monomer having three radical-polymerizable double bonds and the monomer having four or more radical-polymerizable double bonds are used together as three or more radical-polymerizable double bonds in the present invention, the effect of the present invention is improved. The proportion of monomers having 4 or more radical-polymerizable double bonds is 10 to 60% by weight, preferably 20 to 50% by weight relative to the total weight of monomers having 3 or more radical-polymerizable double bonds. When the monomers having four or more radical-polymerizable double bonds are used together, the chemical resistance including alkali resistance and acid resistance is excellent. Such effects are preferably enhanced when the molecular weight per functional group of the monomer having four or more radical-polymerizable double bonds is 30 or more and 200 or less. The reason for the enhancement of such effects is not clear, but is thought to be due to the high degree of three-dimensional crosslinking.

Monomers having one or two polymerizable double bonds in the molecule can be used as long as they do not reduce the effect of the present invention. As monomers, styrene, α-methylstyrene, acrylic esters (e.g. methyl acrylate), methacrylic acid esters (e.g. methyl methacrylate), acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, ethylene Glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, neopentyl glycol diacrylate 1,6-hexanediol diacrylate and Divinylbenzene can be illustrated. These can be used alone or as a mixture thereof. The amount of the monomer (s) used is 0.1 to 10 parts by weight based on 100 parts by weight of the metal pigment. When the amount of use is more than 10 parts by weight, the effect of the present invention, i.e., the use of the obtained resin-coated metal pigment, is reduced, and the thermal stability of the metal pigment is also reduced. Therefore, the resin coating metal pigment is difficult to be practical.

The resin coating metal pigment of this invention is obtained as follows. First, the untreated metal pigment is dispersed in an organic solvent and its surface is (A) radical-polymerizable unsaturated carboxylic acid, phosphoric acid mono- or diester having one or two radical-polymerizable double bonds, and radicals Treatment is carried out by addition of at least one species selected from the group consisting of coupling agents having polymerizable double bonds under heating and stirring. Subsequently, the resin layer is formed on the surface of the metal pigment by performing polymerization by slowly and continuously adding (B) at least one monomer having three or more radically-polymerizable double bonds and at least one of (C) a polymerization initiator.

In the above treatment carried out by first dispersing an untreated metal pigment in an organic solvent and then adding (A) under heating and stirring, the weight concentration of the metal pigment in the organic solvent is not particularly limited, but preferably 1 to 30% by weight. If the concentration is less than 1%, uniform dispersion can be achieved, but the amount of the operating solvent is too large, which undesirably requires a lot of manpower to remove the solvent later. If the concentration is more than 30%, the dispersion of the metal pigment tends to be undesirably even. The treatment is preferably carried out at a temperature of 40-150 ° C. for about 5 minutes to about 10 hours. When the treatment temperature is less than 40 ° C, much time is required to raise the temperature to the polymerization temperature (B). In the case where the treatment temperature is higher than 150 ° C, sufficient care must be taken to prevent ignition of the vapor of the organic solvent and the like. Therefore such a treatment temperature is undesirable. If the treatment time is less than 5 minutes, if the diffusion of (A) is more than 10 hours, time is wasted without enhancing the effect. Therefore such processing time is undesirable.

After the treatment, the polymerization is carried out by continuously adding small amounts of (B) one or more monomers having three or more radical-polymerizable double bonds and (C) a polymerization initiator in small portions successively to form a resin layer on the metal pigment surface. Let's do it. In the present invention, it is important to continuously add at least one of (B) and (C) in small increments. In particular, any of the following methods is used: (B) and (C) are all added in small amounts in series; (C) is added beforehand, and (B) is added continuously little by little continuously; After (B) is added beforehand, (C) is continuously added and added continuously little by little. In the present invention, the high three-dimensional crosslinked resin layer is formed on the metal surface by carrying out the polymerization while continuously supplementing at least one of (B) and (C) little by little. Although polymerization temperature is not specifically limited, Preferably it is 60-150 degreeC. In order to increase the efficiency of the polymerization, the polymerization is preferably carried out under an inert gas such as nitrogen or helium. In order to continuously add at least one of (B) and (C), it is preferable to dilute (B) and / or (C) with an organic solvent or the like and dilute feed at a constant rate with a metering pump or the like. The feed time is preferably at least 20% of the polymerization time. The polymerization time is not particularly limited, but is about 2 to 10 hours. Herein, the term polymerization time means the time required for the unreacted monomer (s) (B) to be less than 1% after the time (B) and (C) are present in the reaction system at the same time. If the feed time (ie, replenishment addition time) is less than 20% of the polymerization time, the effect of continuous addition is undesirably reduced. In order to reduce the reaction time, the feed time is preferably 90% or less of the polymerization time. In order to reduce the reaction time to increase the productivity, the feed time is preferably 70% or less of the polymerization time.

Although the resin-coated metal pigment of the present invention has a slightly increased specific surface area compared to the untreated metal pigment, the increase is much smaller than that of the resin-coated metal pigment obtained by the conventional method. Characterized by having a lower oil absorption. Due to the above characteristics, the coating film formed by using the resin coating metal pigment of the present invention is excellent in chemical resistance, gloss, weather resistance and the like.

Organic solvents used in the polymerization of the present invention include aliphatic hydrocarbons such as hexane, heptane, octane, synthetic spirits (mineral spirits) and the like; Aromatic hydrocarbons such as benzene, toluene, xylene, solvent naphtha and the like; Ethers such as tetrahydrofuran, diethyl ether and the like; And esters such as ethyl acetate, butyl acetate and the like.

Polymerization initiators used in the present invention are generally known as organic radical initiators, and include peroxides such as benzoyl peroxide, lauroyl peroxide, bis- (4-t-butylcyclohexyl) peroxydicarbonate, and the like; Azo compounds such as 2,2'-azobis-isobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile and the like. The amount of the polymerization initiator used is not particularly limited in the present invention, but is about 0.1 to 50 parts by weight per 100 parts by weight of the monomer (s) having three or more radical-polymerizable double bonds.

The coating film formed from the coating material obtained using the resin coating metal pigment of this invention is excellent in alkali resistance. The reason is estimated as follows: The metal pigment surface is covered with a high three-dimensional crosslinked resin layer, so that even if alkali penetrates into the coating film, it hardly reaches the metal pigment surface. The alkali resistance described in the Examples of the present invention has a value of 0.01 to 2.0.

The metal coating of this invention can use an aqueous coating etc. as a solvent type coating, and mainly consists of three components, (a) coating resin, (b) resin coating metal pigment, and (c) diluent.

As coating resin used for a solvent type paint, arbitrary paints normally used for a metal paint can be used. Coating resins include acrylic resins, alkyd resins, oil-free alkyd resins, vinyl chloride resins, urethane resins, melamine resins, unsaturated polyester resins, urea resins, cellulose resins, epoxy resins, fluororesins and the like. These resins can be used alone or as a mixture thereof.

The ratio of the resin coating metal pigment used for the solvent type coating is preferably 0.1 to 100 parts by weight, more preferably 1 to 50 parts by weight based on 100 parts by weight of the coating resin. When the proportion of the resin-coated metal pigment is less than 0.1 part by weight, the paint obtained is not sufficient for the metallic luster required for the metal paint. When the ratio is more than 100 parts by weight, the amount of pigment in the paint is so large that not only the coating efficacy but also the film properties are lowered. Therefore, such a property is not practical.

Diluents used in solvent paints include aromatic compounds such as toluene, xylene, and the like; Aliphatic compounds such as hexane, heptane, octane and the like; Alcohols such as ethanol, butanol and the like; Esters such as ethyl acetate, butyl acetate; Ketones such as methyl ethyl ketone and the like; Chlorine compounds such as trichloroethylene; And cellosolves such as ethylene glycol monoethyl ether and the like. These diluents are used alone or as mixtures thereof. Their binding is determined in view of their solubility, film forming properties, coating efficacy, and the like for the coating resin.

Solvent-based paints can be used as binders with additives such as pigments, dyes, wetting agents, dispersants, color splitting agents, leveling agents, slip agents, skinning agents, antigelling agents, defoamers, etc. do.

The paint of the present invention can be used as an aqueous paint by using a resin for an aqueous paint. Resin for water-based coating contains water-soluble resin and water-dispersible resin. It can be used alone or as a mixture thereof. The resin type of the water-based paint is not particularly limited, but changes infinitely depending on the purpose. In general, the resin for water-based paints includes, for example, acrylic, acrylic-melamine, polyester or polyurethane types for water-based paints. Among these, acrylic-melamine type resins for water-based coatings are most commonly used.

The proportion of the resin-coated metal pigment used in the water-based paint is preferably 0.1 to 100 parts by weight, more preferably 1 to 50 parts by weight with respect to 100 parts by weight of the coating resin. When the proportion of the resin-coated metal pigment is less than 0.1 part by weight, the paint obtained is insufficient in the metallic luster required for the metal paint. When the ratio is more than 100 parts by weight, the amount of the metal pigment in the paint is so large that not only the coating efficiency but also the film properties are lowered. Thus such ratios are not practical.

Various additives such as dispersants, thickeners, anti-sag agents, mildew-proofing agents, fungicides, UV absorbers, film deposition aids, surfactants, other organic solvents, water, etc. are commonly used in the art. It can be added to the water-based paint as long as these kinds and amounts do not reduce the effect of the present invention.

The metal paint of the present invention can be used as a paint generally used in addition to a solvent paint and an aqueous paint. Paints generally used include powder paints.

Embodiments of the invention are described below and should be understood as not limiting the scope of the invention. In addition, the test method and the measuring method used in the present examples are described in detail below.

(1) Production of evaluation plate

Using the resin coating aluminum paste, according to the paint formulation shown in Table 1, the metal coating material for alkali resistance evaluation is manufactured.

Mixing ratio of paints (parts by weight) Resin-coated aluminum paste (in nonvolatile matter) 9 Thinner * 1 40 Acrylic resin * 2 100 Nitrocellulose Resin Solution * 3 50 * 1: Mixture of butyl acetate (30 parts), toluene (40 parts), isopropanol (20 parts) and ethyl cellosolve (5 parts). * 2: ACRYDIC A-166 (non-volatile content: 45%) (Dainippon Ink room temperature-curable acrylic resin manufactured by and Chemicals, Inc.). * 3: Thinner * 1 was used as LIG 1/2 (non-volatile content: 70%) (industrial nitrocellulose manufactured by ASAHI Chemical Industry Co., Ltd.). Obtained by adjusting the nonvolatile content to 16%.

After adjusting the viscosity of the said coating material to 13 second (FC # 4, 20 degreeC) using the thinner of the said Table 1, spray coating is carried out so that a film thickness may be set to 10 micrometers on an ABS resin plate. Subsequently, the ABS resin plate is dried at 50 ° C. for 30 minutes to prepare an evaluation plate.

(2) Measurement of alkali resistance.

The lower half of the plate is immersed in an aqueous 2.5 N NaOH solution in a beaker and left at 20 ° C. for 24 hours. The treated plate was washed with water and dried, and the immersed portion and the non-immersed portion were measured for color according to the condition d (8-d method) in JIS-Z-8722 (1982), and JIS-Z- 8730 (1980), 6.3.2. Find the color difference ΔE along the DP.

(3) gloss retention

For the above plate, 60 ° gloss 20 (incidence angle and reflection angle: 60 °) is measured with a glossmeter. Gloss retention R is calculated by the formula:

R = (G '/ G) x 100

[Wherein G is 60 ° gloss of untreated aluminum paste, and G 'is 60 ° gloss of resin-coated aluminum paste].

(4) oil absorption

Using the resin coated aluminum paste heat-treated at 105 degreeC for 3 hours as a sample, its oil absorption amount is measured by using dibutyl phthalate according to the method B (knife kneading method) in JISK 6221-1982.

(5) specific surface area

The solvent contained in the aluminum paste is removed by acetone substitution, and the surface of the powdery sample obtained thereby is measured by a BET one-point specific surface area meter (Shimadatsu FLOWSORB 2300).

Example 1

Into a 1-liter four-necked flask, 75 g of aluminum paste (MG-51 manufactured by ASAHI Chemical Industry Co., Ltd .; metal content: 67%) and 300 g of synthetic spirit were added and stirred while introducing nitrogen gas. And the temperature in the system are raised to 80 ° C. 0.375 g of acrylic acid is then added and stirring is continued at 80 ° C. for 30 minutes. Then 2.5 g of trimethylolpropane trimethacrylate, 1.0 g of di-trimethylolpropane tetraacrylate (molecular weight per functional group: 116.5) and 0.35 g of 2,2'-azobis-2,4-dimethylvalero Nitrile is dissolved in 19 g of synthetic alcohol and the resulting solution is added to the mixture obtained using a metering pump at a rate of about 0.13 g / min for 3 hours. Thereafter, the polymerization is carried out for a total of 6 hours while maintaining the temperature in the system at 80 ° C. At this time, the amount of unreacted trimethylolpropane trimethacrylate in the sample of the filtrate was measured by gas chromatography, and it was found that 99.5% or more of added trimethylolpropane trimethacrylate reacted. After completion of the polymerization, the slurry thus obtained was filtered to obtain a resin coated aluminum paste. The nonvolatile content (according to JIS-K-5910) of the paste is 65.0 weight%. Resin coating amount is 8.3 weight part with respect to 100 weight part of metal aluminum. From these results, at least 98 mole% of acrylic acid, trimethylolpropane trimethacrylate, ditrimethylolpropane tetraacrylate and 2,2'-azobis-2,4-dimethyl-valeronitrile adhered to the aluminum surface, respectively. This is estimated.

Example 2

A resin-coated aluminum paste was prepared in the same manner as in Example 1, except that 3.5 g of trimethylolpropane trimethacrylate was used instead of trimethylolpropane trimethacrylate and di-trimethylolpropane tetraacrylate.

Example 3

Into a 1-liter four-necked flask, 75 g of aluminum paste (MG-51 manufactured by ASAHI Chemical Industry Co., Ltd .; metal content: 67%) and 300 g of synthetic spirit were added and stirred while introducing nitrogen gas. And the temperature in the system are raised to 60 ° C. 0.375 g of acrylic acid is then added and stirring is continued at 60 ° C. for 30 minutes. 6.4 g of trimethylolpropane tetraacrylate and 1.6 g of di-pentaerythritol hexaacrylate (molecular weight per functional group: 96.3) are then dispersed in the system. Subsequently, 0.8 g of 2,2'-azobis-2,4-dimethylvalero-nitrile are dissolved in 19 g of synthetic alcohol and the resulting solution is metered in at a rate of about 0.08 g / min for 4 hours. Is added to the mixture obtained above. Thereafter, the polymerization is carried out for a total of 7 hours while maintaining the temperature in the system at 60 ° C. After completion of the polymerization, the slurry thus obtained was filtered to obtain a resin coated aluminum paste. The nonvolatile content of the paste (according to JIS-K-5910) is 60.0% by weight. The resin coating amount is 18.2 parts by weight based on 100 parts by weight of metal aluminum. From these results, it was confirmed that at least 99 mole% of acrylic acid, trimethylolpropane triacrylate, di-pentaerythritol hexaacrylate and 2,2'-azobis-2,4-dimethylvaleronitrile were attached to the aluminum surface, respectively. It is estimated.

Example 4

Into a 1-liter four-neck flask, 75 g of aluminum paste (MG-51 manufactured by ASAHI Chemical Industry Co., Ltd .; metal content: 67%) and 300 g of synthetic spirit were added and stirred while introducing nitrogen gas. And the temperature in the system are raised to 70 ° C. 0.4 g of acrylic acid is then added and stirring is continued at 80 ° C. for 30 minutes. 0.5 g of 1,6-hexanediol diacrylate, 3.0 g of trimethylolpropane trimethacrylate, 1.5 g of pentaerythritol hexaacrylate (molecular weight per functional group: 88) and 0.5 g of azobisisobutino Nitrile is dissolved in 38 g of synthetic alcohol and the resulting solution is added to the mixture obtained using a metering pump at a rate of about 0.24 g / min for 3 hours. Thereafter, the polymerization is carried out for a total of 6 hours while maintaining the temperature in the system at 80 ° C. After completion of the polymerization, the slurry thus obtained was filtered to obtain a resin coated aluminum paste. The nonvolatile content of the paste (according to JIS-K-5910) is 62.0% by weight. Resin coating amount is 11.6 weight part with respect to 100 weight part of metal aluminum. From these results, at least 98 mole% of acrylic acid, 1,6-hexanediol diacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, and 2,2'-azobisisobutyronitrile were respectively surfaced on aluminum. Is assumed to be attached to.

Example 5

A resin-coated aluminum paste was prepared in the same manner as in Example 1 except that the amounts of trimethylolpropane trimethacrylate and di-trimethylolpropane tetraacrylate were changed from 1.0 g to 2.5 g, respectively. The nonvolatile content (according to JIS-K-5910) in the paste is 60.0%.

Example 6

2.5 g trimethylolpropane trimethacrylate, 1.0 g di-trimethylolpropane tetraacrylate and 0.35 g 2,2'-azobis-2,4-dimethylvaleronitrile solution in 19 g of synthetic alcohol A resin-coated aluminum paste was prepared in the same manner as in Example 1, except that it was added using a metering pump at a rate of 0.32 g / min for 1.2 hours. The nonvolatile content (JIS-K-5910) in the paste is 65.0%.

Example 7

150 g of aluminum paste (MG-51 manufactured by ASAHI Chemical Industry Co., Ltd .; metal content: 67%) and 600 g of 2-propanol were added to a two-liter four-neck flask with a capacity of 2 liters, and stirred while introducing nitrogen gas. And the temperature in a system is raised to 70 degreeC. Subsequently, 7 g of vinyltrimethoxysilane and 7 g of deionized water are added, followed by stirring for 5 hours. The slurry thus obtained is filtered and the residue is washed thoroughly with synthetic alcohol. Into a 1-liter four-necked flask, 75 g of paste and 300 g of synthetic spirit obtained therein were put, stirred while introducing nitrogen gas, and the temperature in the system was raised to 80 ° C. Subsequently, 19 g of trimethylolpropane trimethacrylate, 1.0 g of di-trimethylolpropane tetraacrylate, and 0.35 g of 2,2'-azobis-2,4-dimethylvaleronitrile were synthesized. It is dissolved in alcohol and the resulting solution is added to the obtained mixture using a metering pump at a rate of about 0.13 g / min for 3 hours. Thereafter, the polymerization is carried out for a total of 6 hours while maintaining the temperature in the system at 80 ° C. After completion of the polymerization, the slurry thus obtained was filtered to obtain a resin coated aluminum paste. The nonvolatile content of the paste (according to JIS-K-5910) is 65.0% by weight. Resin coating amount is 8.3 weight part with respect to 100 weight part of metal aluminum. From these results, at least 98 mol% of vinyl trimethoxy silane, trimethylolpropane trimethacrylate, di-trimethylolpropane tetraacrylate, and 2,2'-azobis-2,4-dimethylvaleronitrile, respectively. It is assumed to adhere to the surface.

Example 8

A resin-coated aluminum paste was prepared in the same manner as in Example 1 except that 2-methacryloyloxyethyl acid phosphate (MR-200 manufactured by DAIHACHI CHEMICAL) was used instead of acrylic acid. The nonvolatile content (according to JIS-K-5910) in the paste is 65.0%. From these results, 98 mol% or more of 2-methacryloyloxyethyl acid phosphate, trimethylolpropane trimethacrylate, di-trimethylolpropane tetraacrylate, and 2,2'-azobis-2,4-dimethylvalle, respectively It is assumed that ronitrile is attached to the aluminum surface.

Comparative Example 1

A resin-coated aluminum paste was prepared in the same manner as in Example 1, except that the monomer (B) and the polymerization initiator were simultaneously added instead of performing a continuous supplemental addition little by little using a pump.

Comparative Example 2

A resin-coated aluminum paste was prepared in the same manner as in Example 2, except that the monomer (B) and the polymerization initiator were simultaneously added instead of performing a continuous replenishment in small portions using a pump.

Comparative Example 3

2.5 g trimethylolpropane trimethacrylate, 1.0 g di-trimethylolpropane tetraacrylate and 0.35 g 2,2'-azobis-2,4-dimethylvaleronitrile solution in 19 g of synthetic alcohol A resin-coated aluminum paste was prepared in the same manner as in Example 1 except for adding with a metering pump at a rate of about 0.76 g / min for 0.5 hour. The nonvolatile content (according to JIS-K-5910) in the paste is 60.0%.

Comparative Example 4

Instead of the combination of trimethylolpropane trimethacrylate and di-trimethylolpropane tetraacrylate, 0.88 g of vinyltrimethoxysilane, 0.06 g of phosphoric acid, 0.06 g of water and 1.00 g of 2-butanol were used, and 19 Resin-coated aluminum paste was prepared in the same manner as in Example 1, except that trimethylolpropane trimethacrylate solution in g of synthetic spirit was added using a metering pump at a rate of about 0.78 g / min for 0.5 hour. do. The nonvolatile content (according to JIS-K-5910) in the paste is 60.0%.

Comparative Example 5

A resin-coated aluminum paste was prepared in the same manner as in Example 1, except that 19 g of trimethylolpropane trimethacrylate solution in a synthetic spirit was added instead of a small amount of continuous supplemental addition using a metering pump. The nonvolatile content (according to JIS-K-5910) in the paste is 60.0%.

Table 2 shows the paste performance characteristics of Examples 1-8 and Comparative Examples 1-5.

In Table 2, the term polyfunctional monomer content means the percentage (weight percent) of monomers having four or more radical-polymerizable double bonds contained in the total monomer (s) having three or more radical-polymerizable double bonds. do.

Performance characteristics of the paste Polyfunctional monomer * 1 content (%) Supplemental addition time * 2 (%) Oil absorption (g / g) Storage stability in water based paints * 3 Alkali resistance ΔE (8-d method) Glossy retention rate (%) Example 1 29 50 1.42 ○ 0.7 91 Example 2 0 50 1.61 ○ 1.7 90 Example 3 20 57 1.56 ○ 0.2 90 Example 4 33 50 1.45 ○ 0.3 90 Example 5 71 50 1.70 ○ 2.0 89 Example 6 29 20 1.60 ○ 1.0 90 Example 7 29 50 1.31 ○ 0.2 92 Example 8 29 50 1.41 ○ 0.6 90 Comparative Example 1 29 0 1.82 × 2.5 88 Comparative Example 2 0 0 1.90 × 3.0 85 Comparative Example 3 29 8 1.84 × 2.3 88 Comparative Example 4 0 7 1.44 ○ 15.0 88 Comparative Example 5 0 0 1.44 ○ 17.0 88 * 1: monomers having four or more radical-polymerizable double bonds * 2: percentage of component (B) and / or component (C) feed time in polymerization time * 3: storage stability in water-based paint ○; Amount of gas produced: less than 10 (cc / g) x; Amount of gas produced: more than 10 (cc / g)

Example 9

The resin coated aluminum paste obtained in Example 1, the resin coated aluminum paste obtained in Comparative Example 2, a resin-uncoated aluminum paste (MG-51, manufactured by ASAHI CHEMICAL INDUSTRY Co., Ltd.), and fluororesin were used, respectively. Then, a paint is manufactured according to the paint mix ratio shown in Table 3. Each paint is applied on an aluminum plate (1 × 70 × 150 mm) by air spray to a thickness of 30 μm. The aluminum plate is then dried at 100 ° C. for 30 minutes to prepare a metal coating film composed mainly of fluororesin.

Paint compounding ratio (part by weight) LUMIFURON LF200 * 1 100 Aluminum paste 10.2 DURANATE TPA-100 * 2 7.8 Thinner * 3 150 total 268.0 * 1: Asahi Glass Co., Ltd. manufacture * 2: Asahi Chemical Industry Co., Ltd. manufacture * 3: Toluene / xylene / ethyl acetate / butyl acetate ratio = 30/20/20/30

After using the metal coating film, the chemical-resistant spot test at 20 degreeC is performed for 10 days, a discoloration degree is evaluated. In addition, an exposure test for 3,000 hours with a Sunshine weatherometer (SWOM) is carried out using the same coating. In chemical resistance testing, 10% aqueous hydrochloric acid solution, 10% aqueous NaOH solution and 10% aqueous sulfuric acid solution are used as chemicals, respectively. The results are shown in Table 4.

Evaluation of discoloration of coating film Aluminum paste Discoloration degree of coating 100% HCl Spot Test 10% NaOH Spot Test 10% H ₂ SO ₄ Spot Test Sunshine Weatherometer Test Resin-coated aluminum paste of Example 1 ○ ○ ○ ○ Resin-coated Aluminum Paste of Comparative Example 2 △ △ ○ △ MG-51 (untreated aluminum paste) × × × △ ○: No discoloration △: Slight acid discoloration ×: Many discoloration

The coating film manufactured using the resin coating aluminum paste of Example 1 of this invention did not change at all in the chemical-resistance test. In addition, in the test performed using the sunshine weatherometer, the coating film prepared using the resin-coated aluminum paste of Example 1 of the present invention showed little change in appearance, that is, exhibited excellent weather resistance.

Example 10

Using vinylidene fluoride type fluororesin as the resin component, the paint was prepared according to the paint mix ratio shown in Table 5. Each coating material was apply | coated with the bar coater to the thickness of 30 micrometers on an aluminum plate, and it dried at 240 degreeC for 5 minutes, and manufactures a coating film. The chemical resistance spot test is performed in the same manner as in Example 9. As a result, the coating film manufactured using the resin coating aluminum paste of Example 1 shows the very outstanding chemical-resistance like Example 9.

Paint compounding ratio (part by weight) Paraloid B-44 * 1 15.2 Aluminum paste (as 100% non-volatile content) 9.2 Thinner * 2 120.0 NEOFLON VDF VP-850 * 3 45.6 total 190.0 * 1: ROHM HAAS Co. Preparation * 2: isophorone / dimethyl phthalate / toluene / isobutyl acetate / ethyl acetate ratio = 45/24/15/8/8 * 3: Daikin Industries

Example 11

Using the resin coating aluminum paste of Example 1 and the resin coating aluminum paste of Comparative Example 2, respectively, an acrylic paint is manufactured according to the paint formulation of Table 6. Each paint is applied to the ABS resin plate by air spraying to a thickness of 30 mu m. After drying an ABS resin plate at room temperature for 24 hours, the 60 degree glossiness of the coating film formed thereon is measured. Although the coating film manufactured using the resin coating aluminum paste of Example 1 has 65% of high gloss, the coating film manufactured using the resin coating aluminum paste of Comparative Example 2 has a gloss of 53%.

Paint compounding ratio (part by weight) ACRYDIC (trade name) A-801 * 1 100 Aluminum paste (as 100% non-volatile content) 10.2 DURANATE TPA-100 7.8 Thinner * 2 150 Catalyst (Dibutyl Dilaurate) 268.0 total 242.2 * 1: Dainippon Ink Chemical Co., Ltd. make * 2: Ethyl acetate / butyl acetate / toluene / xylene / propyl methoxyacetate ratio = 20/30/30/15/5.

Example 12

In the case of the resin-coated aluminum pastes of Examples 1 to 8 and Comparative Examples 1 to 5, the storage stability in the water-based coating was evaluated by producing the coating using the pastes according to the formulations in Table 7, respectively. Place 100 g of each paint in a 200 ml Elenmeyer (triangle) flask and attach a measuring pipette with a rubber stopper to the flask. Table 2 given above shows the amount of product gas measured after leaving the flask at 50 ° C. for 24 hours. Further, using the resin-coated aluminum paste of Example 1, an aqueous paint was prepared according to the blending ratios shown in Table 7, and was then applied onto an aluminum plate by air spraying at a thickness of 30 μm, followed by drying at 170 ° C. for 20 minutes. To produce a coating film. This coating film is excellent in a metallic feeling.

Paint compounding ratio (part by weight) Metal powder of resin coating metal pigment 2821 Water soluble acrylic resin (heating residue = 50%) * 1 370 Water-soluble acrylic resin (heating residue = 50%) * 2 100 pure 491 total 3782 * 1: Resin prepared by adding dimethyl ethanolamine to Almatex WA-911 (manufactured by Mitsui Toatsu Chemicals, Inc.) and adjusting to pH 9. * 2: CYMEL 350 (manufactured by Mitsui Cytec Ltd.)

Example 13

The specific surface area of the resin coating aluminum paste of Example 1, the resin coating aluminum paste of Comparative Example 2, and the resin coating aluminum paste (MG-51, ASAHI Chemical Co., Ltd. product) is measured. The results obtained are shown in Table 8. The specific surface areas of the resin coated aluminum paste of Example 1 and the resin coated aluminum paste of Comparative Example 2 were 1.9 and 3.0 times, respectively, of the aluminum paste not coated with resin. From this fact, it is considered that the resin-coated aluminum paste of Example 1 was coated with a highly three-dimensional crosslinked resin.

Specific surface area Specific surface area (S) (m ² / g) (S of resin coating Al) / (S of Al not coated with resin) Example 1 10.5 1.9 Comparative Example 2 16.3 3.0 MG-51 5.5 -

Example 14

A resin-coated aluminum paste was produced in the same manner as in Example 1 except that MH-8801 (manufactured by Asahi Chemical Industry Co., Ltd .; metal content: 65%) was used instead of the aluminum paste used in Example 1. By measuring the alkali resistance of the resin-coated aluminum paste, the color difference was found to be ΔE = 0.3. Therefore, the resin coating aluminum paste showed the outstanding alkali resistance.

Comparative Example 6

A resin-coated aluminum paste was produced in the same manner as in Comparative Example 2 except that MH-8801 (manufactured by Asahi Chemical Co., Ltd .; metal content: 65%) was used instead of the aluminum paste used in Comparative Example 2. By measuring the alkali resistance of the resin-coated aluminum paste, it was found that the color difference was ΔE = 3.1.

Example 15

The specific surface areas of the resin-coated aluminum paste of Example 14, the resin-coated aluminum paste of Comparative Example 6, and the aluminum paste (MH-8801, manufactured by Asahi Chemical Industry Co., Ltd.) not coated with resin were measured, respectively. The results obtained are shown in Table 9. The specific surface areas of the resin coated aluminum paste of Example 14 and the resin coated aluminum paste of Comparative Example 6 were 1.5 and 3.0 times, respectively, of the aluminum paste not coated with resin. From this fact, it is considered that the resin-coated aluminum paste of Example 13 was coated with a highly three-dimensional crosslinked resin.

Specific surface area Specific surface area (S) (m ² / g) (S of resin coating Al) / (S of Al not coated with resin) Example 14 14.2 1.5 Comparative Example 6 28.5 3.0 MH-8801 9.5 -

The resin coating metal pigment of this invention is coat | covered with resin which has a high crosslinking density, and is excellent in chemical resistance, weather resistance, and storage stability. In addition, since the resin-coated metal pigment has a small surface area and a low oil absorption amount, it is possible to minimize gloss reduction by coating with a resin.

The resin coated metal pigment of the present invention can be suitably used as a pigment incorporated in metal paints and printing inks or in plastics for the above reasons.

In addition, the resin-coated metal pigment of the present invention is excellent in weather resistance, for example, it is a product product which requires durability such as automobile parts such as bodies, bumpers, side mirrors, building exterior components such as tiles, roofing materials, wall materials, and home electric appliances. It can be used suitably.

Claims (6)

(A) a group consisting of a radically polymerizable unsaturated carboxylic acid and / or a mono or diester of phosphoric acid having one or two radically polymerizable double bonds and / or a coupling agent having a radical-polymerizable double bond At least one species selected from (B) at least one monomer having at least three radical-polymerizable double bonds, and (C) a polymerization initiator, and (A) is first added to treat the metal pigment, followed by (B A resin-coated metal pigment having a resin layer formed on the surface of a metal pigment by polymerization carried out by continuously supplementing at least one of (C) and (C) little by little. The method of claim 1, wherein as the monomer having at least three radically polymerizable double bonds, a monomer having three radically polymerizable double bonds and a monomer having at least four radically polymerizable double bonds are used together, The resin coating metal pigment whose ratio of the monomer which has four or more radically polymerizable double bonds with respect to the total amount of the monomer which has three or more double bonds is 10 to 60 weight%. The resin-coated metal pigment according to claim 1 or 2, which is supplemented with at least one of (B) and (C) for at least 20% of the polymerization time. The resin coating metal pigment in any one of Claims 1-3 whose molecular weight per functional group of the monomer which has four or more radically polymerizable double bonds is 30 or more and 200 or less. The resin coating metal pigment as described in any one of Claims 1-4 which has alkali resistance of 2.0 or less. The metal coating material containing the resin coating metal pigment of any one of Claims 1-5.