JPS62253668A - Novel resin-coated metallic pigment and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a novel resin-coated metal pigment, and more specifically, when used as a paint pigment, it exhibits chemical resistance, water resistance,
The present invention relates to a resin-coated metal pigment that provides a metallic coating film with excellent cosmetic resistance, fingerprint resistance, etc. The present invention also relates to a resin-coated metal pigment for use in plastic kneading, which has unprecedented heat resistance stability and storage stability.

[Conventional technology and its problems]

Conventionally, metal pigments have been used in metallic paints, printing inks, plastic kneading, etc., for the purpose of obtaining cosmetic effects that emphasize metallic appearance.

However, when used as a metallic paint, the metal pigment and resin components of the paint react with each other during storage, causing the paint to gel and become unusable.

Another disadvantage is that the water contained in the paint reacts with the metal pigment bones to generate gas, which deforms the container. This gas generation is significantly accelerated in the presence of acid or alkaline components, leaving problems with storage stability.

Furthermore, the paint film obtained by painting with metallic paint does not have sufficient chemical resistance such as acid resistance and alkali resistance, and water resistance, and the painted surface changes color and loses gloss over time. The uses of metallic paint are limited.

In recent years, metallic coatings have been used in a wide range of applications, and not only higher chemical resistance and water resistance than before are required, but also metallic coatings with excellent cosmetic resistance and fingerprint resistance. Cosmetic resistance refers to the performance against the phenomenon that cosmetics adhering to a metallic coating film leaves stains on the coating film, and fingerprint resistance refers to the performance against the phenomenon that cosmetics adhering to a metallic coating film leaves stains on the coating film. This is the performance against the phenomenon of floating. Both of these significantly reduce the commercial value of metallic coatings. In addition, when conventional metal pigments are used for kneading into plastics, for example, into resins such as polyethylene and polyvinyl chloride, the metal pigments have poor compatibility with the resin, making it difficult for the metal pigments to be uniformly dispersed. Therefore, the desired uniform sheet or film cannot be obtained. Furthermore, when blended with polyvinyl chloride, the surface of the metal pigment changes color due to hydrogen chloride generated from the polyvinyl chloride, causing loss of metallic luster.

As a solution to these problems, a method has been proposed in which the metal pigment component is coated with a resin.

One known method for resin coating is a method (Japanese Patent Publication No. 56-43069) in which a solution prepared in advance by dissolving a resin in a solvent is mixed with a pigment suspension, and the resin is deposited on the pigment. There is.

However, with this method, the pigment particles can be coated uniformly on the surface of the pigment particles.
Moreover, it is difficult to firmly adhere the resin. In the resin coating made by this method, the resin layer is merely physically attached to the metal surface, and its adhesion is weak. Therefore, the resin coating layer peels off or dissolves due to mechanical external force applied during the pigment dispersion process during paint manufacturing, or due to dissolution or softening by the solvent contained in the paint manufactured using resin-coated pigments, and the desired effect is not achieved. Significantly impaired.

In addition, it is easily melted or softened by applying heat, and the effect of resin coating cannot be obtained sufficiently when used for kneading plastics.

Furthermore, attempts have been made to proceed with the polymerization of monomers in a system in which metal pigments are dispersed, and simultaneously manufacture the resin and coat the pigment surface. Attempts have been made to create a chemical bond between the resin and the metal pigment component (Japanese Unexamined Patent Application Publication No. 50-2
Publication No. 6837). However, in addition to manufacturing problems such as the complicated and long manufacturing process, the formation of a resin layer on the pigment surface is not controlled, and as a result, sufficient water and chemical resistance effects cannot be achieved, and it has not yet been implemented industrially. This has not yet been achieved.

In addition, a method has been proposed in which a gold tsR material is dispersed in water and polymerization is carried out under conditions that produce a positively charged polymer during polymerization (Japanese Patent Publication No. 53-4029). Even with this method, effects such as sufficient water resistance, alkali resistance, acid resistance, etc. cannot be obtained, and it has not been put into practical use industrially.

Furthermore, a method is known in which the surface of metal particles is coated with a resin obtained by proceeding a polymerization reaction in an organic solvent in which the monomer is soluble and the resulting polymer is insoluble (Japanese Patent Application Laid-Open No.
No. 6-181470, Japanese Unexamined Patent Publication No. 11818/1983)
However, the resin-coated metal pigment R materials produced by these methods have not yet reached a practically sufficient level in terms of chemical resistance, water resistance, especially cosmetic resistance, fingerprint resistance, etc., and improvements are needed. is necessary.

In addition, this resin-coated metal pigment also does not have sufficient heat resistance stability, so when it is used for kneading and placed at high temperatures (150°C or higher), the resin coated with the metal pigment tends to soften. Bonding between pigments occurs, making it difficult to obtain the desired uniformly dispersed film or sheet.

[Means for solving problems]

The present inventors have attempted to solve these problems with conventional metal pigments (as a result of intensive research, we have developed a monomer containing a radically polymerizable double bond and a carboxyl group in one molecule or a radically polymerizable dual bond). The inventors have discovered that the object can be achieved by firmly adhering a highly three-dimensional resin layer to the surface of a metal pigment by taking advantage of the properties of phosphoric acid mono- or diesters having heavy bonds, leading to the present invention.

That is, the present invention provides surface coating with a resin produced from a radically polymerizable unsaturated carboxylic acid and/or a phosphoric acid mono- or diester having a radically polymerizable double bond, and a monomer having three or more radically polymerizable double bonds. It's been done,
The present invention also relates to a resin-coated metal pigment having an alkali resistance of 1.0 or less, and further relates to a resin-coated metal pigment that does not substantially agglomerate in a heat resistance stability test.

In addition, the first step of dispersing the metal pigment in an organic solvent and adding a radically polymerizable unsaturated carboxylic acid and/or a phosphoric acid mono- or diester having radically polymerizable double bonds, which has three or more radically polymerizable double bonds. The present invention relates to a method for producing a resin-coated metal pigment, which comprises a second step of adding and polymerizing a monomer and an initiator.

The resin-coated metal pigment according to the present invention exhibits unprecedented heat resistance stability, and when stored as a pigment for a long period of time, pigment aggregation is not observed, and other characteristics (
It has excellent storage stability with no change in alkali resistance, water resistance, etc.), and when used as a pigment for metallic paints, the paint has excellent storage stability, and has excellent chemical resistance, water resistance, and Provides a coating film that exhibits excellent cosmetic resistance and fingerprint resistance.

The radically polymerizable unsaturated carboxylic acid in the present invention is
These include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, etc., and they are used alone or in combination of two or more. The amount used will vary depending on the type and properties of the metal pigment, especially the surface area, but generally 100% of the metal pigment! 0.
The amount is between 0.01 and 10 parts by weight. 0.01ii
If the amount is less than 3 parts, the effects of the present invention, i.e., chemical resistance such as water resistance and acid resistance, fingerprint resistance, etc., will not be exhibited satisfactorily, and the next molecule will contain 3 polymerizable double bonds. When polymerizing monomers having more than 1, the polymerization system may gel and become unstirable. Moreover, if it exceeds 10 parts by weight, water resistance will decrease. This is presumed to be because the amount of carboxyl groups contained in the radically polymerizable unsaturated carboxylic acid is too large.

In the present invention, the phosphoric acid ester monomer having a radically polymerizable double bond includes 2-methacryloyloxyethyl phosphate, di-2-methacryloyloxyethyl phosphate, tri-2-methacryloyloxyethyl phosphate, and 2-acryloyloxyethyl phosphate. Ethyl phosphate, di-2-
Acryloyloxyethyl phosphate, tri-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, diphenyl-2
-Acryloyloxyethyl phosphate, dibutyl-2
-methacryloyloxyethyl phosphate, dibutyl-
2-acryloyloxyethyl phosphate, dioctyl-2-methacryloyloxyethyl phosphate, dioctyl-2-acryloyloxyethyl phosphate, 2-
These include methachloroyloxyethyl phosphate, bis(2-chloroethyl)vinylphosphonate, diallyldibutylphosphonosuccinate, etc., and they are used alone or in combination of two or more thereof.

Phosphoric acid monoester can be mentioned as a preferable phosphoric ester having a radically polymerizable double bond. This is presumed to be due to the presence of two OH groups in the phosphoric acid group, which causes the phosphoric acid group to be more firmly fixed to the surface of the aluminum particles. More preferable phosphoric acid monoesters include monoesters having a methacroyloxy group and an acroyloxy group, such as 2-methacryloyloxyethyl phosphate and 2-acryloyloxyethyl phosphate. These monoesters are often insoluble in common polymerization solvents.

The amount used is gold! The type and characteristics of the pigment vary depending on the surface area, but generally 0 parts by weight per 100 parts by weight of the metal pigment.
．． 01 parts by weight to 30 parts by weight.

If it is less than 0.01 parts by weight, the effects of the present invention, that is, chemical resistance such as water resistance and acid resistance, fingerprint resistance, etc., will not be exhibited well, and even if it is used in excess of 30 parts by weight. , there is almost no increase in effect.

Examples of monomers having three or more polymerizable double bonds in one molecule used in the present invention include trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, tetramethylolmethane triacrylate, and tetramethylolmethanetetraacrylate. One or more of these may be used.

The amount used is 2 parts by weight per 100 parts by weight of the metal content of the metal pigment.
Between 50 parts by weight and less than 2 parts by weight,
The effect of the present invention, that is, the chemical resistance decreases, and if it exceeds 100 parts by weight, no increase in the effect is expected, and the brightness, gloss,
The basic characteristics of a metallic paint, such as a metallic feel, deteriorate, making it difficult to put it into practical use.

A monomer having 1 to 2 polymerizable double bonds in one molecule within a range that does not impair the effects of the present invention, that is, 0 to 10 parts by weight based on 100 parts by weight of the metal content of the metal pigment. may be used. If the amount used exceeds 10 parts by weight, the effects of the present invention, that is, when a metallic coating film is created using the resulting resin-coated metallic pigment, the properties will decrease, and the heat resistance stability of the metallic pigment will also decrease. , it is difficult to put it into practical use.

Monomers having 1 to 211 m of polymerizable double bonds in one molecule used in the present invention include styrene, α-methylstyrene, acrylic esters such as methyl acrylate, and methacrylates such as methyl methacrylate. Acid esters, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, neopentyl glycol diacrylate, divinylbenzene, etc. One or more of these may be used.

The polymerization initiator used in the present invention is generally known as a radical generator, and includes peroxides such as benzoyl peroxide, lauroyl peroxide, isobutyl peroxide, methyl ethyl ketone peroxide, and azobisisobutyl peroxide. Lonitrile and the like.

The polymerization initiator is used in an amount of 0.1 to 50 parts by weight per 100 parts by weight of a monomer having three or more polymerizable double bonds in one molecule.
Use parts by weight. Preferably, 1 to 20 parts by weight is used. If it is less than 0.1 part by weight per 100 parts by weight of a monomer having three or more polymerizable double bonds in one molecule, it will take a long time to polymerize and is not practical.

If it exceeds 50 parts by weight, the polymerization rate is too fast to be controlled and is not practical.

The alkali resistance of the present invention refers to the coating film obtained by blending and painting the specified paint with 08IN, Na011 aqueous solution at 55°C.
The condition of the coating film before and after dipping was determined according to JIS-Z-
8722 < 1982) condition + 1 < 9-d method), and refers to the color difference (ΔE, ) determined from JIS-Z-87306, 3, 2D.

The prescribed paint is a paint using a waste village type acrylic/melamine resin, and the pigment concentration is 100 parts by weight of acrylic/melamine resin (non-volatile content), and the pigment concentration is 15 parts by weight. Add the required amount of thinner. The acrylic resin used here is a commonly available acrylic resin for baking, and the melamine resin is a commonly available butylated melamine resin. The mixing ratio is 30 to 10 parts by weight of melamine resin to 70 to 90 parts by weight of acrylic resin.

The resin-coated metal pigment of the present invention has an alkali resistance of 1.0 or less, preferably 0.8 or less. If it exceeds 1.0, discoloration of the coating film will be visually observed, it will not have sufficient alkali resistance, and it will not be included in the present invention.

In the present invention, a resin-coated metal pigment that does not substantially agglomerate in a heat stability test is one that shows almost no change in particle size when a predetermined temperature is applied to the resin-coated metal pigment for a predetermined period of time. That is, a heat resistance stability test was conducted in the same manner except that the temperature of JIS-54008, 2, 1 was changed to 150°C, the time was changed to 1 hour, and the amount of sample obtained was changed to Log.
Agglomeration is measured by the ratio of the particle size dll before the test to the particle size dyo after the test.

The resin-coated metal pigment of the present invention has a d/d; of 1.5 or less, more preferably 1.3 or less. If it exceeds 1.5, it is not preferable because uniform dispersion of the metal pigment cannot be obtained during high-temperature molding such as kneading.

A radically polymerizable unsaturated carboxylic acid and/or a phosphoric acid mono- or diester having a radically polymerizable double bond, and a monomer having three or more radically polymerizable double bonds were classified, and the surface was covered with the resulting resin. The preferred method for producing the metal pigment of the present invention is to first disperse a gold mR pigment in an organic solvent, and then add a radically polymerizable unsaturated carboxylic acid and/or a phosphoric acid mono- or diester having a radically polymerizable double bond. Step process, radically polymerizable double bonds are removed by 3
This is a manufacturing method that involves a second step of polymerizing by adding a monomer having at least 1 or more monomers and an initiator.

The first step is to disperse metal pigment particles in a solvent, then add a radically polymerizable unsaturated carboxylic acid or a phosphoric acid mono- or diester having a radically polymerizable double bond while continuing to stir. done by

Although the treatment temperature in the first step may be room temperature, it is preferable to add salt to 30 to 80°C.

The treatment time is generally 5 minutes or more, preferably 10 minutes or more, although the first step ends when the concentration of the unsaturated carboxylic acid or phosphoric acid ester remaining in the solvent becomes constant.

In performing the first step, there is also a method in which a part or all of the monomer having three or more radically polymerizable double bonds to be added in the second step has already been added.

However, in order to complete the first step quickly and reliably, monomers having 3 fl1 or more radically polymerizable double bonds are added in the second step before the completion of the first step. In order to completely stop the initiation of polymerization, it is preferable that the first step does not contain a monomer having three or more radically polymerizable double bonds to be added in the second step. If such an initiator is added in the first step, the performance of the resulting resin-coated metal pigment will be significantly reduced, making it difficult to put it to practical use.

As a result, the carboxyl group of the radically polymerizable unsaturated carboxylic acid or the phosphoric acid group of the phosphoric acid ester having a radically polymerizable double bond is fixed on the surface of the metal pigment, and pigment particles having a radically polymerizable double bond on the surface are obtained. It is estimated that

This estimation is based on the fact that after the first step, the metal pigment is filtered out and the amount of radically polymerizable unsaturated carboxylic acid or phosphoric acid mono- or diester having a radically polymerizable double bond remaining in the solvent is quantified. This is supported by the fact that there is a significant decrease compared to the amount.

The second step proceeds after the first step is completed by adding a monomer having three or more polymerizable double bonds in one molecule and an initiator, followed by heating and stirring.

Through this operation, the double bond based on the unsaturated carboxylic acid previously fixed on the surface of the metal pigment and the monomer having three or more polymerizable double bonds in one molecule copolymerize, resulting in a highly cross-linked structure on the surface of the metal pigment. However, it is presumed that the excellent effects of the present invention are only manifested when a resin layer with a high network density is formed in a form that has chemical bonds with the surface of the metal pigment. This assumption is believed to be supported by the fact that the heat resistance stability of the resin-coated metal pigment of the present invention is significantly improved and there is almost no aggregation after the test.

It is preferable to replace the reaction system with an inert gas such as nitrogen or argon.Although the temperature varies depending on the type of initiator, it is generally between 30°C and 150°C.The reaction time is 30 minutes to 10 minutes. It's between hours.

The reaction may be carried out by adding the monomer and/or initiator all at once or by adding them in portions.

In carrying out the second step, a radically polymerizable unsaturated carboxylic acid or a phosphoric acid ester having a radically polymerizable double bond, a monomer having three or more polymerizable double bonds in one molecule, and an initiator are used. If they are added all at once and the polymerization reaction is started immediately, the effects of the present invention will not be exhibited.

In addition, without using radically polymerizable unsaturated carboxylic acids or phosphoric esters having radically polymerizable double bonds, only monomers having 3 (II or more) polymerizable double bonds in one molecule are dispersed in an organic solvent. If polymerization is carried out in the presence of metallic pigment particles, that is, if the first step is omitted and the second step is started, the polymerization system may not only thicken and be unable to be stirred, but also the resulting resin-coated metal The performance of the pigment is very poor.

This fact indicates that the metal surface is not sufficiently covered with the resin layer. These findings highlight the necessity of a first step prior to a second step.

Metal pigments used in the present invention include aluminum, copper,
Zinc, iron, nickel, and/or their alloys are used, and aluminum is a preferred example. Its shape is granular, such as flakes, conglomerates, and needles. The particle size of metal pigments varies depending on the application. For paints and printing, an average diameter of about 1 to LQOμ is good (for kneading into plastics, about 1 to 200μ is good, but it is not particularly limited and can be applied to the present invention).

To explain in detail about the aluminum pigment used in the present invention, aluminum flakes or granular powder are processed by a mechanical method such as a stamp mill method, a dry ball mill method, a wet ball mill method, an attritor method, a vibrating ball mill method, etc.
It is made by grinding with a grinding aid. This grinding aid functions as a grinding aid and at the same time influences the physical properties of the aluminum pigment. Conventionally, higher saturated or unsaturated fatty acids such as stearic acid and oleic acid, and higher aliphatic amines such as stearylamine are often used as the grinding aid, but regardless of these grinding aids, the present invention You can get the effect. Aluminum pigments obtained using stearic acid are generally well known as leafing type aluminum pastes, and are used as silver paints for tanks and other metal rust prevention applications. In addition, aluminum pigments obtained using oleic acid, stearylamine, etc. are generally well known as non-leafing type aluminum pastes, and are used as metallic paints for automobiles, furniture, etc.
Used for cosmetic purposes.

Organic solvents used in the polymerization of the present invention include aliphatic hydrocarbons (e.g. hexane, heptane, octane, mineral spirits, etc.), aromatic hydrocarbons (e.g. benzene, toluene, solvent naphtha, xylene, etc.), esters (acetic acid ethyl, butyl acetate, etc.), ethers (tetrahydrofuran, diethyl ether, etc.), and metal pigments 10
50M parts to 3000 parts by weight are used for 0 parts by weight.

Preferably it is between 250 and 1000 parts by weight. If it is less than 50 parts by weight based on 100 parts by weight of the metal pigment, it will become paste-like and a radically polymerizable unsaturated carboxylic acid and 1
It is not preferable because it takes a long time to uniformly diffuse the monomer having three or more polymerizable double bonds in the molecule and the polymerization initiator.

If it exceeds 3000 parts by weight, the polymerization time will become longer, which is not preferable.

After forming a resin coating layer on the surface of the metal pigment in the organic solvent as described above, the organic solvent was filtered off and the non-volatile content was removed by 3.
A paste containing the resin-coated metal pigment of the present invention is obtained, adjusted to 0 to 80% and added with other solvents, additives, etc. as necessary.

The resin-coated metal pigment of the present invention comprises (a) paint resin 100;
(b) 0.1 part by weight of the resin-coated metal pigment of the present invention
A metallic paint can be obtained by using parts by weight to 100 parts by weight and (iii) diluting thinner.

As the paint resin, any of the paint resins conventionally used in metallic paints can be used.
Furthermore, it can also be used for resins that have a large amount of functional groups that react with metals and easily cause gelation, which have not been used in conventional metallic paints. These 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, etc. They may be used alone or in combination.

The resin-coated metal pigment of the present invention has a negative o and iz content of 100 parts by weight based on 100 parts by weight of the paint resin.

In particular, it is preferable to use 1 part by weight to 50 parts by weight.

If the amount of this resin-coated metallic pigment is less than 0.1 part by weight, the metallic luster necessary for a metallic paint will be insufficient, and if it is used in excess of 100 parts by weight, the amount of metallic pigment in the paint will increase. If it is too high, it not only has poor painting workability, but also has poor physical properties, making it impractical.

Examples of diluent thinners include aromatic compounds such as toluene and xylene, aliphatic compounds such as hexane, heptane, and octane, alcohols such as ethanol and butanol, esters such as ethyl acetate and butyl acetate, and ketones such as methyl ethyl ketone. , chlorine compounds such as trichlorethylene, and cellosols such as ethylene glycol monoethyl ether. It is preferable to use a mixture of two or more of these solvents. Determined by taking into consideration paint film formation characteristics, painting workability, etc.

In addition, additives such as pigments, dyes, wetting agents, dispersants, color separation inhibitors, leveling agents, slip agents, anti-skinning agents, anti-gelling agents, anti-foaming agents, etc. commonly used in the paint industry. It is possible to add

【Example〕

Next, examples of the present invention will be described.First, the test methods and measurement methods used in the examples will be described in detail.

[Amount of coating resin per 100 parts by weight of aluminum metal] Paste 10 containing the resin-coated aluminum pigment of the present invention
Disperse g well in chloroform (reagent) 100a+1 and extract the soluble content.Next, the extraction residue, the resin-coated aluminum pigment, is vacuum-dried at 80°C for 1 hour and powdered.
Take 1.0g and add 6N-HCI (reagent) 200a+
Step 1: Melt the metal aluminum part little by little. The remaining insoluble resin content is filtered, and after vacuum drying at 80° C. for 14 hours, the weight is measured, and the resin content relative to 100 parts by weight of aluminum metal content is calculated.

[Alkali resistance]

A metallic paint for alkali resistance evaluation is prepared by using the resin-coated aluminum pigment and formulating the paint as shown below.

[Paint formulation]

(Parts by weight) Resin-coated aluminum pigment (non-volatile content) 7.5 Acrylic/melamine resin *1100 *1 Niacridic 47-712 (Non-volatile content: 50
%), 20 parts of Super Beckamine J-820 (non-volatile content = 50%) (manufactured by Nippon Reichhold) *2: Toluene (70 parts), ethyl acetate (20 parts), butyl cellosolve (10 parts) The paint was then air sprayed onto an aluminum plate (70x1
50 x 1 mm (manufactured by Nippon Test Panel ■) to a film thickness of 20μ, and this coated plate was heated at 140°C for 30 minutes.
Dry for 0 minutes and use as a test coating to determine alkali resistance. This coating has an inner diameter of 34+m+*.

A vinyl chloride cylinder with a height of 15a + w is fixed with metal fittings, and
．． Add 5 ml of 1N-NaOH and leave at 55°C for 4 hours. After standing for 4 hours, the vinyl chloride cylinder is removed, the test coating is thoroughly washed with water, and the coating is dried.

The coating film before and after the Kono coating film was tested according to JIS-Z-8722 (1
982) under condition d (method 9-d), JI
Calculate color difference ΔE1 according to 6.3.2 of S-Z-8730 (1980) (Measurement #li: SR-4 manufactured by Suga Test Instruments ■)
-MCI type).

[Acid resistance]

0, lN-NaOH to 0. It is carried out in the same manner as the alkali resistance except that it is changed to 1N-H2SO4.

[Agglomeration by heat stability test]

Weigh out 10g of the paste containing the resin-coated aluminum pigment, put it in a bottle, and put it in a dryer kept at a temperature of 150°C.
Heat for an hour. The particle size characteristic number of this resin-coated aluminum pigment was wet-sieved using mineral spirit as a dispersion medium, and the analysis results were determined according to the German Industrial Standards Part IN-4190.
RR5 grain size diagram (Rosin-Rastaler-3
pering grain size diagram). This value is d
The particle size characteristic number is determined in the same manner for the resin-coated aluminum pigment before zero-order heating.

Let these values be d and l. Obtain the value of dQ/d, 1 by calculation.

The sieve used here is a JIS standard sieve for 44μ or more, and a micromesh sieve (Buck) for less than 44μ.
bee-wears Company product).

(Cosmetic Resistance) A resin-coated aluminum pigment is used and the following paint formulation is carried out to make a paint for plastic coating.

[Paint formulation]

[Parts by weight] Paste containing resin-coated aluminum pigment (non-volatile content equivalent) 9 Thinner *1 40 Acrylic resin
*2100 *Pa* -1-Ball the paint and reduce the viscosity with thinner (*1) for 13 seconds (FC#4.
20℃) and spray it onto the ABS board to a film thickness of 1.
0 μ), dried at room temperature for 3 days, and used for cosmetic resistance test.

Cosmetics (Atrix hand cream: manufactured by Kao Soap Co., Ltd.) are applied to half of the test coating to a thickness of about 1 m. Next, this coating film is left in a constant temperature and humidity bath adjusted to a temperature of 60° C. and a humidity of 90% for 5 days.

After the test, the paint film is washed with water, the moisture is wiped off, and after drying at room temperature for 1 hour, the appearance of the paint film on the areas with and without cosmetics applied is visually compared.

[Fingerprint resistance]

A coating film is prepared in the same manner as for cosmetic resistance, except that a fingertip is placed on an ABS board in advance to leave a fingerprint mark.

Immerse the entire test coating in a beaker containing warm water at 60°C.
Leave it for 3 hours.

After the test, the coating film is washed with water, the moisture is wiped off, and after drying at room temperature for 1 hour, the appearance of fingerprint marks is visually judged.

Example 1 Aluminum paste (Asahi Kasei Kogyo Co., Ltd. 1M601, metal content 65°2%) was placed in a 1000ml three-neck flask.
, average particle size 11 μm, flaky shape) and 400 g of Mineral Subirif T- were added, and the mixture was stirred while introducing nitrogen gas, and the temperature in the system was raised to 80°C. Next, 375 g of acrylic acid (reagent) was added and heated to 80°C.
Stirring was continued for 30 minutes, then 7.5 g of trimethylolpropane trimethacrylate (reagent) and 0,075 g of azobisisobutyronitrile (reagent) were added, and the mixture was heated to 80°C.
Polymerization was carried out for 5 hours. After the polymerization was completed, the slurry was allowed to cool to room temperature (1) and filtered to obtain a paste containing a resin-coated aluminum pigment. The nonvolatile content (according to JIS-5910) of this paste was 51.0% by weight. The amount of coating resin per 100 parts by weight of aluminum metal was 11.
It was 4 parts by weight. It is estimated that 99% or more of acrylic acid, trimethylolpropane trimethacrylate, and azobisisobutyronitrile were deposited on the aluminum metal surface.

Alkali resistance of this resin-coated aluminum pigment (68M
) was 0.3, acid resistance (ΔEH) was also 0.3, and a good coating film was obtained with almost no discoloration.

Further, when the coating film was immersed in warm water at 60° C. for 7 days, there was almost no discoloration and the coating film was good. The paint was stored at 50°C for one month, but it was in good condition with no gelation.

The aggregation (dQ/d;) after the heat resistance stability test was 1.05, and the powder had a uniform appearance, with virtually no aggregation observed.

Example 2 Aluminum paste (Asahi Kasei Corporation 11MB-21, metal content 72
．． 0%, average particle size 24μ, flaky shape) 118
g and 325 g of mineral spirit were added thereto, and the mixture was stirred while introducing nitrogen gas, and the temperature in the system was raised to 80°C.

Next, 0.255 g of acrylic acid (reagent) was added and stirring was continued at 80°C for 30 minutes. Next, 4.25 g of trimethylolpropane trimethacrylate (reagent) and 0.43 g of abbisisobutyronitrile (reagent) were added and polymerized at 80° C. for 5 hours. After the polymerization was completed, the slurry was allowed to cool to room temperature and filtered to obtain a paste containing a resin-coated aluminum pigment. The non-volatile content of this paste (JI
-5910) was 60.2% by weight.

The amount of coating resin was 5.7 parts by weight based on 100 parts by weight of aluminum metal. It is estimated that 98% or more of acrylic acid, trimethylolpropane trimethacrylate, and azobisisobutyronitrile were deposited on the aluminum metal surface.

Alkali resistance (ΔE) of this resin-coated aluminum pigment
4) was O42, acid resistance (ΔE, ) was 0.1, and agglomeration (d4/d: ) after the heat resistance stability test was 1.05, and the resin-coated aluminum pigment of the present invention was obtained.

Example 3 Aluminum paste (manufactured by Asahi Kasei Corporation 4/62, metal content 67.3
%, average particle size 9 μm, flake-like shape) and 400 g of mineral spirit were added, and the mixture was stirred while introducing nitrogen gas, and the temperature in the system was raised to 80° C.

Next, 0.525 g of acrylic acid (reagent) was added and stirring was continued at 80°C for 30 minutes. Next, 10.5 g of trimethylolpropane trimethacrylate (reagent) and 0.525 g of azobisisobutyronitrile (reagent) were added and polymerized at 80°C for 6 hours. After completion of the polymerization, the slurry was allowed to cool to room temperature. A paste containing resin-coated aluminum pigment was obtained by filtration. Non-volatile content of this paste (J
IS-5910) was 53.0% by weight. The amount of coating resin corresponding to 100 parts by weight of aluminum metal was 16.4 parts by weight. It is estimated that 99% or more of acrylic acid, trimethylolpropane trimethacrylate, and azobisisobutyronitrile were deposited on the aluminum metal surface.

The alkali resistance (ΔE,
) was 0.6, the acid resistance (ΔEN) was 0.1, and the aggregation (di/d,') after the heat resistance stability test was 1.10, and the resin-coated aluminum pigment of the present invention was obtained.

Example 4 115 g of the aluminum paste M-601 used in Example 1 and 400 g of mineral spirit were added to a 1000a+1 three-bottle flask, stirred while introducing nitrogen gas, and the temperature in the system was raised to 65°C. Next, 0.375 g of methacrylic acid (reagent) was added and the mixture was heated at 65°C.
Stirring was continued for 0 minutes. Then, 7.5 g of trimethylolpropane triacrylate (reagent) and 0.75 g of azobisisobutyronitrile (reagent) were added and polymerized at 65° C. for 7 hours. After completion of the ii reaction, the slurry was allowed to cool to room temperature, and the slurry was filtered to obtain a paste containing a resin-coated aluminum pigment. Non-volatile content of this paste (JIS-T591
0) was 47.5% by weight.

The amount of coating resin was 11.2 parts by weight based on 100 parts by weight of aluminum metal. It is estimated that 97.4% of methacrylic acid, trimethylolpropane triacrylate, and azobisisobutyronitrile were deposited on the aluminum metal surface.

Alkali resistance (ΔEH) of this resin-coated aluminum pigment
) was 0.4, acid resistance (ΔEH) was 0.5, and aggregation after heat resistance stability test (d:1/d; ) was 1.08, and the resin-coated aluminum pigment of the present invention was obtained.

Examples 5 to 7, Comparative Examples 1 to 2 Using the aluminum paste MG-21 used in Example 2, the polymerization shown in Table 1 was carried out in the same manner as in the preparation of the resin-coated aluminum pigment in Example 2, and the resin-coated aluminum A paste containing pigment was obtained.

In Comparative Example 1, only trimethylolpropacitrimethacrylate was polymerized, but the viscosity of the slurry in the system increased 1 hour after the start of polymerization, making stirring difficult. This is presumably because the aluminum particles did not adhere to the surfaces of the aluminum particles because acrylic acid treatment was not performed, and polymerization proceeded in the organic solvent (mineral spirit).

As shown in Table 1, Examples 5 to 7 showed extremely good performance, but Comparative Example 1 had poor alkali resistance, presumably because it was not coated with resin. Comparative Example 2 also showed inferior performance compared to Examples 5-7. This is presumed to be because the amount of carboxyl groups contained in acrylic acid was too large.

Examples 8 to 9, Comparative Example 3 Using the aluminum paste M-60I used in Example 1, the polymerization shown in Table 2 was carried out in the same manner as in the preparation of the resin-coated aluminum pigment in Example 1, and the resin-coated aluminum pigment was A paste containing was obtained.

In Comparative Example 3, trimethylolpropane trimethacrylate, acrylic acid, and an initiator were simultaneously added and polymerized. The viscosity of the slurry in the system increased 1 hour after the start of polymerization. This does not adhere well to the surface of the aluminum particles, and organic solvents (
It is presumed that the polymerization progressed within days of mineral removal.

As the results are shown in Table 2, Examples 8 and 9 showed extremely good performance, but Comparative Example 3 showed poor alkali resistance, presumably because the resin was not coated.

(The following is a blank space) Example 10 A paste containing a resin-coated aluminum pigment was obtained in the same manner as in Example 1 except that acrylic acid was changed to 2-methacryloyloxyethyl phosphate.

Non-volatile content of this paste (according to JIS4-5910)
was 54.0% by weight. Aluminum metal content 100
The amount of N-subjected resin relative to parts by weight was 11.4 parts by weight.

This is 2-methacryloyloxyethyl phosphate,
It is estimated that 99% or more of trimethylolpropane trimethacrylate and azobisisobutyronitrile were deposited on the aluminum metal surface.

Alkali resistance of this resin-coated aluminum pigment (8EH
) was 0.2, acid resistance (ΔEH) was 0.1, and a good coating film was obtained with almost no discoloration. Also, soak the paint film in warm water at 60℃ for 7 days.
When immersed for one day, the coating film was good with almost no discoloration. The paint was stored at 50°C for one month, but it was in good condition with no gelation.

The aggregation <d;, /d;> after the heat resistance stability test was 1.03, and the powder had a uniform appearance, with virtually no aggregation observed.

Example 11 A paste containing the resin-coated aluminum pigment of the present invention was obtained in the same manner as in Example 2, except that 2-methacryloyloxyethyl phosphate was used instead of acrylic acid. The nonvolatile content (according to JIS-5910) of this paste is 59.
It was 0% by weight. The amount of coating resin was 5.8 parts by weight based on 100 parts by weight of aluminum metal. This is 2
- It is estimated that more than 99% of methacryloyloxyethyl phosphate, trimethylolpropane trimethacrylate, and azobisisobutyronitrile were deposited on the aluminum metal surface.

Alkali resistance (ΔEH) of this resin-coated aluminum pigment
) is 0.3, acid resistance (ΔEH) is 0.2, and agglomeration (di/d; ”) after heat resistance stability test is 1.10,
A resin-coated aluminum pigment of the present invention was obtained.

Example 12 A paste containing the resin-coated aluminum pigment of the present invention was obtained in the same manner as in Example 1 except that acrylic acid was replaced with 2-acryloyloxyethyl phosphate. The nonvolatile content of this paste (according to JIS-X-5910) is 51.0
% by weight. The amount of coating resin was 5.8 parts by weight based on 100 parts by weight of aluminum metal. This is 2-
It is estimated that 99% or more of the acryloyloxyethyl phosphate, trimethylolpropane trimethacrylate, and azobisisobutyronitrile were deposited on the aluminum metal surface.

Alkali resistance (ΔEH) of this resin-coated aluminum pigment
) was 0.5, the acid resistance (ΔEH) was 0.3, and the agglomeration (d, i/d, ") after the heat resistance stability test was 1.05, and the resin-coated aluminum pigment of the present invention was obtained. Ta.

Example 13 The resin-coated aluminum of the present invention was prepared in the same manner as in Example 2 except that 0.255 g of acrylic acid was changed to 2.55 g of 2-methacryloyloxyphosphate and 4.25 g of trimethylolpropane trimethacrylate was changed to 8.5 g. A paste containing pigment was obtained. Non-volatile content of this paste (JIS
-5910) was 57.9% by weight.

The amount of coating resin was 13.4 parts by weight based on 100 parts by weight of aluminum metal. This is 99% of 2-mecryloyloxyethyl phosphate, trimethylolpropane trimethacrylate, and azobisisobutyronitrile.
It is presumed that the above substances adhered to the aluminum metal surface.

The alkali resistance (ΔE,
) is 0.1, acid resistance (ΔE1.l) is 1, and aggregation after heat stability test (di/d; ) is 1°15
The resin-coated aluminum pigment of the present invention was obtained.

Example 14 (1) R-made resin-coated aluminum pigment of Comparative Example 4 A paste containing a resin-coated aluminum pigment was obtained in the same manner as in Example 1 except that trimethylolpropane trimethacrylate was replaced with ethylene glycol dimethacrylate (reagent). Ta. Non-volatile content of this paste (JIS-59
10) was 51.5% by weight.

(2) Preparation of resin-coated aluminum pigment of Comparative Example 5 A paste containing a resin-coated aluminum pigment was obtained in the same manner as in Example 10, except that ethylene glycol dimethacrylate (reagent) was used instead of trimethylolpropane trimethacrylate. Non-volatile content of this paste (JIS-ni-5
910) was 49.5% by weight.

Resin-coated aluminum pigments of Comparative Examples 4 and 5 and Example 1
and 10 resin-coated aluminum pigments [alkali resistance, acid resistance, fingerprint resistance, cosmetic resistance, agglomeration after heat stability test (d:!, /d;)] were compared.

As shown in Table 3, Examples 1 and 10 exhibited extremely superior performance compared to Comparative Examples 4 and 5.

(Margin below)

Claims (3)

[Claims] (1) The surface is coated with a resin produced from a radically polymerizable unsaturated carboxylic acid and/or a phosphoric acid mono- or diester having a radically polymerizable double bond, and a monomer having three or more radically polymerizable double bonds. and a resin-coated metal pigment having an alkali resistance of 1.0 or less. (2) The resin-coated metal pigment according to claim 1, which does not substantially agglomerate in a heat resistance stability test. (3) The surface is coated with a resin produced from a radically polymerizable unsaturated carboxylic acid and/or a phosphoric acid mono- or diester having a radically polymerizable double bond, and a monomer having three or more radically polymerizable double bonds. In the production of a resin-coated metal pigment having an alkali resistance of 1.0 or less, the metal pigment is dispersed in an organic solvent, and a radically polymerizable unsaturated carboxylic acid and/or a phosphoric acid mono- or radically polymerizable double bond-containing mono- or A method for producing a resin-coated metal pigment, which comprises a first step of adding a diester, and a second step of adding and polymerizing a monomer having three or more radically polymerizable double bonds and an initiator.