JPH0241370A - Production of metallic pigment having good weather resistance - Google Patents

Abstract

PURPOSE:To obtain the title pigment capable of providing metallic feeling having depth by subjecting a specific metal powder to ionic reaction with a specific metal oxide ultrafine particle powder at a specific ration and coordinating metal oxide ultrafine particle powder on the surface of metallic powder. CONSTITUTION:(A) A metal powder such as aluminum having 1.0-100mu particle size obtained by absorbing using a cationic dispersing agent (e.g., N-acylamino acid salt) of 0.5-5wt.% based on the metal powder is dispersed in a polar solvent, preferably such as a ketone based solvent and then (B) ultrafine particle powder of metal oxide such as titanium oxide having 0.01-0.1mu particle size obtained by absorbing using an anionic dispersing agent of 1-5% based on the ultrafine particle powder is added thereto so that ratio of the component A to the component B is 100:1-10 and the component A is subjected to ionic reaction with the component B to provide the aimed consisting of component B coordinated on the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a metallic pigment with good weather resistance and a metallic paint using the same.

(Prior Art) Metallic pigments used in metallic paints have conventionally been produced by mechanical methods such as stamp milling, dry ball milling (Hametag), etc.
This method is known in the art.

(Problems to be Solved by the Invention) Aluminum paste is mainly used as a metallic pigment, but since the surface of ground paste aluminum powder is active, maleic acid, stearic acid,
These are made by adsorbing fatty acids and amines on the surface of aluminum, but because they cannot sufficiently prevent the activation of aluminum, for example, when a paint film is formed with metallic paint, the paint film deteriorates due to sunlight. There was a problem in that the metallic feel of the coating film rapidly deteriorated after exposure.

Furthermore, metal powders such as copper, brass, chromium, nickel, cobalt, and stainless steel are being used as metallic pigments instead of the aluminum powder normally used in metallic paints as new color types, but when turned into paints, Since the active sites cannot be completely prevented, there is a problem that the weather resistance is poor and the characteristic metallic color of the metal disappears over time.

On the other hand, Japanese Patent Publication No. 59-15152 describes an organic solvent type flaky metal pigment composition using dimers and higher fatty acids and a method for producing the same, but it does not take into account the deterioration of the coating film when it is made into a paint. Not yet.

Further, 1. Japanese Patent Publication No. 17142/1989 discloses a new flaky metal powder pigment, but does not particularly mention deterioration of the pigment when it is formed into a coating film.

(Means for Solving the Problem) The inventor of the present application focused on this point and applied visible light (3B to 7B) to the surface of metal powder such as aluminum powder, copper, brass, chromium, nickel, cobalt, and stainless steel. , nm), metal oxide ultrafine particle powder (particle size 0.1-0
．． We thought that the weather resistance could be improved by coordinating 01μ), and as a result of various studies, we arrived at the present invention.

Normally, metallic pigments adsorb fatty acids and amines on the surface of metal powder, but they are made of aluminum powder coated with ultrafine titanium oxide or ultrafine iron oxide, and a silyl group-containing vinyl polymer or copolymer. Metallic pigments coated with a synthetic polymer compound that has at least one hydrolytically bonded silicon group in each molecule at the end or side chain have even better weather resistance, combined with the good weather resistance of the resin itself. Become.

Furthermore, as a secondary effect, the metal oxide ultrafine particle powder used in the present invention has transparency because its average particle size is smaller than the wavelength of visible light. For this reason, not only does it not inhibit the gloss of the metallic pigment, but also a synergistic effect of the metallic feel and the transparent coloring effect provides a deep metallic feel that was not initially expected, leading to the present invention.

Next, the constituent elements of the present invention will be explained.

The metal powder used in the present invention is a treated metal powder that requires the use of a cationic surfactant instead of mineral spirit or higher fatty acid treatment.

There is no particular restriction on the average particle size of the metal powder, and it is 1 to 10.
Although those with a diameter of 0μ can be used, those with a diameter of 10 to 50μ are particularly preferred. If the particle size is 100 μm or more, when made into a paint, it tends to settle due to the difference in specific gravity, and if the particle size is 1 μm or less, the metal oxide ultrafine particle powder is difficult to adsorb.

As the cationic surfactant to be adsorbed on the surface of the metal powder of the present invention, N-acylamino acid salts (dialkyldimethylammonium chloride), alkylpyridium salts, etc. can be used.

As a method for adsorbing the above-mentioned cationic surfactant onto the metal powder, a conventional method may be used during the soft texturing process (mechanical crushing). That is, when producing treated metal powder by the known method of finely pulverizing metal powder while spreading it with mineral spirit in a ball mill, by using 0.5 to 5 wt% of a cationic surfactant, the cationic surfactant Surfactants can be adsorbed around the metal powder.

The surface treatment of the metal powder is usually carried out through the intervention of mineral spirits, but a ketone solvent or cellosolve solvent, which is a polar solvent, may also be used in combination. In this way, treated metal powder adsorbed with a cationic surfactant can be produced, but the amount of cationic surfactant used is Q,
If it is less than 5 wt%, the coordination of the metal oxide ultrafine particles will not be sufficient, and if it is more than 5 wt%, the weather resistance of the paint film will be reduced when the metallic pigment is used in a paint.

Next, examples of the metal oxide ultrafine particle powder adsorbed with an anionic surfactant used in the present invention include titanium oxide, iron oxide (■), zinc oxide, cobalt oxide, chromium oxide (■), Examples include alumina, but especially iron oxide (
The method for producing I[) is described in Japanese Patent Publication No. 52-13528.
A method of pulverizing layered or burr-like coagulable polycrystalline hydrated iron oxide particles after dehydration by firing at 700°C, as shown in No.
55 (1) 13-19 1982, the following colloid chemical method is disclosed, but this does not limit the present invention.

Specifically, an anion exchange resin is added to an aqueous ferric chloride solution to create a transparent positive hydrated iron oxide sol, an anionic surfactant is added to this sol to aggregate colloidal particles, and the aggregated particles are flushed to form an organic By transferring the mixture into a solvent layer and removing water and organic solvent therefrom, ultrafine metal oxide particles having an anionic surfactant adsorbed thereon are produced.

In addition, a colloidal chemical method as a method for producing titanium oxide is disclosed in Color Materials, 57 (6) 305-308. This is an example of a method and is not intended to limit the invention.

Specifically, an aqueous titanyl sulfate solution is added with an aqueous sodium carbonate solution to form a hydrosil, an anionic surfactant is added to convert the colloidal particles to lipophilicity, and then flushed with an organic solvent to form an organosol, which is then mixed with water and an organic solvent. By removing the anionic surfactant, ultrafine particles of titanium oxide can be synthesized.

Anionic surfactants that can be used in metal oxide ultrafine particle powders include alkylbenzene sulfonates,
Alkanesulfonate, α-olefin sulfonate,
α-Sulfo fatty acid, N-acylamino acid salt, N-(2-
Examples include sulfo)ethyl-N-methylalkanamide salt, dialkyl 2-sulfosuccinate salt, and alkylnaphthalene sulfonate.

Among these, alkylbenzene sulfonate and 2-
Dialkyl sulfosuccinates are good, but more specifically, sodium dodecylbenzenesulfonate and (2-
Sodium ethylhexyl sulfosuccinate is useful, and in the case of colloid chemical methods such as those mentioned above, when used to aggregate colloid particles, anionic surfactants are formed around the metal oxide ultrafine particle powder. Can be absorbed. The amount of anionic surfactant used is 1wt% to 5w
The t% is appropriate; if it is less than 1wt%, the ultrafine metal particles will not be completely lipophilized and the ionic reaction with the treated metal powder will not proceed smoothly. Moreover, if the amount is more than 5 wt%, the weather resistance of the formed metallic pigment will decrease.

The surface of the treated metal powder produced by gI as described above has been treated with lipophilic agents, so it can be used with aromatic solvents such as xylene and toluene, and esters such as ethyl acetate, i-propyl acetate, or n-butyl acetate. Typical examples include ketone-based solvents such as methyl ethyl ketone, methyl isobutyl ketone, or cyclohexanone, or cellosolve-based solvents such as methyl cellosolve, ethyl cellosolve, or butyl cellosolve, which smooth ionic reactions. Polar solvents, ie, ketone solvents or cellosolve solvents, are suitable for this purpose.

After dispersing the treated metal powder in a ketone-based solvent or cellosolve-based solvent, the reaction can be initiated by adding ultrafine metal oxide particles with anions adsorbed on the surface in a range of 1wt% to 1Qwt% of the treated metal powder. Since the reaction proceeds instantaneously, by removing the used solvent after the reaction, it is possible to produce a metallic pigment with good weather resistance, which is the object of the present invention.

If the amount of ultrafine metal oxide particles is more than 10 wt% of the treated metal powder, free ultrafine metal oxide particles that do not adsorb to the treated metal powder will exist in the metallic pigment, making the pigment itself expensive. Moreover, it becomes difficult to produce a deep metallic feel.

Additionally, if the amount of ultrafine metal oxide particles used is less than 1wt%, the ultrafine metal oxide particles will not be able to completely cover the treated metal powder, and the weather resistance of metallic paints using this will be significantly reduced. decreases to

In the ionic reaction of the present invention, no special processing equipment is required, and the reaction can be carried out using a stirrer for uniform mixing.

In order to further improve the weather resistance of the metallic pigment in the present invention, one molecule of a silicon group whose main chain is made of a silyl group-containing vinyl polymer or copolymer and which is bonded to a hydrolyzable group at the molecular terminal or side chain is added. When a metallic pigment is coated with a so-called acrylic silicone resin having at least one resin in the pigment, the weather resistance of the pigment is further improved since the resin itself has good weather resistance.

Particularly in the case of metallic paints that contain organic pigments such as anthraquinone, perylene, and pyranthrone, when ordinary metallic pigments are used, they have poor storage stability, such as hue changes and significant viscosity changes during storage. gB aggregation may cause lumps, but when used in combination with the metallic pigment of the present invention, the storage stability is good and the viscosity over time is stable in an accelerated storage test in which the pigment is stored at 50°C, which was a problem in the past. No whelk was observed.

When the metallic pigment of the present invention is used, the clear reason for the above effect cannot be explained, but it is thought that it is probably because the active sites on the surface of the metal powder are blocked by the metal oxide ultrafine particle powder.

Examples of uses of the metallic pigment of the present invention having good weather resistance include the following.

(1) In addition to metallic paints commonly used as paints, it can be used in heat reflective paints, conductive paints, decorative paints, powder paints, etc.

(2) Gravure ink and Off-Self as raw materials for ink)
Can be used for ink, etc.

(3) Since the pigment of the present invention has an ultraviolet absorption effect, it can be used in cosmetics, plastic molded products, paints, etc.

(4) PC concrete, aluminum die-cast board,
As shown in Table 2, a deep metallic feel was observed when the metallic paint was applied to various inorganic building materials such as various siding boards and extruded boards, especially molded boards with elaborate designs.

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

(Reference example 1) [How to make aluminum-based treated powder] ■Atomized aluminum powder (manufactured by Toyo Aluminum)
AAIOI) 1.0kg■Methyl isobutyl ketone 1.2577■Strong thionic dispersant (stearyldimethylbenzylammonium chloride)
25 g was placed in a ball mill with a diameter of 50 cm, and pulverized for 2 hours and 30 minutes. After the pulverization was completed, it was washed with 81 ml of methyl isobutyl ketone and passed through a 325 methane screen. Thereafter, solid-liquid separation was performed using a pan filter to obtain a filter cake consisting of 7QwL% of metal powder.

Methyl isobutyl ketone was added to this filter cake so that the metal powder content was 55 wt %, and the mixture was kneaded for 30 minutes using a kneader to obtain an aluminum paste. The particle diameter measured with Microtrack was α=25.0 (μ).

(Reference Example 2) [How to make iron oxide ultrafine powder] Add 500 g of anion exchange resin (Amberlite IRA-400) to 10% ferric chloride aqueous solution 11.
The solution is added, left to stand for 1 hour, and then filtered to produce a transparent positive hydrated iron oxide sol. Then 50 m of this positive hydrated iron oxide sol
1, and add 50rr/! of an aqueous solution of sodium dodecylbenzenesulfonate at a concentration of 3% to this! is added to aggregate the colloid particles. Add 50m of methyl isobutyl ketone to this sol.
By adding J and vigorously shaking the mixture in a flushing operation, the sol transferred to the organic phase, which was methyl isobutyl ketone, and became a transparent blood red color. The size of this sol (metal oxide ultrafine powder, transparent iron oxide) was measured using an electron microscope and was found to be 0.02 to 0.04 (μ).

(Reference Example 3) [How to make titanium oxide ultrafine particle powder] 500 mj of titanyl sulfate aqueous solution with a concentration of 1%! While stirring, reduce the concentration to 15
% of soda carbonate at a rate of 20ml/11 minutes, titanium hydroxide precipitates. After filtering this, B
, add 0 ml of dilute hydrochloric acid and heat to 70°C. When this is cooled to room temperature, transparent titanium hydroxide hydrosil is obtained. Next, 50 mj2 of this sol was taken out, and 50 m of an aqueous solution of sodium dodecylbenzenesulfonate with a concentration of 3% was added.
1 was added and adsorbed on the surface of the colloidal particles, 50 ml of methyl isobutyl ketone was added thereto, and the mixture was transferred to the methyl isobutyl ketone phase by a flushing operation of vigorous shaking. When the organic solvent was removed from this sol by heating under reduced pressure, titanium oxide ultrafine particle powder was obtained. When the size of this powder is measured using an electron microscope, it is 0.01 to 0.
．． It was 02 (μ).

(Example 1) Ultrafine iron oxide particle powder in which sodium dodecylbenzenesulfonate was adsorbed on aluminum paste loog (solid content 65%, solvent: methyl isobutyl ketone) in Reference Example 1, in which a cationic dispersant was adsorbed on the surface. 3.5 g of chlorine was gradually added thereto, and the mixture was heated and stirred at 30° C. for 10 minutes. After filtering the treated paste and drying, 55 g of a red metallic pigment was obtained.

(Example 2) Ultrafine titanium oxide particles with sodium 2-ethylhexylsulfosuccinate adsorbed on 100 g of the aluminum paste of Reference Example 1 (solid content 65%, solvent: methyl ethyl ketone) with a cationic dispersant adsorbed on the surface. 4 g of powder was gradually added and mixed with stirring. The treated paste was filtered and dried to yield 58 g of metallic pigment.

(Example 3) 20 g of the metallic pigment obtained in Example 1 was diluted with toluene and immersed for 1 hour in an acrylic silicone resin solution (Zemlac manufactured by Kanebuchi Chemical Industry @) prepared to have a solid content of 4%. After filtration and drying, 20.2 g of resin-coated metallic pigment was obtained.

(Example 4) Titanium oxide ultrafine particle powder in which sodium dodecylbenzenesulfonate was adsorbed on 100 g of aluminum paste (solid content 65%, solvent: methyl ethyl ketone) with a cationic dispersant adsorbed on the surface. Gradually add Og,
The mixture was heated and stirred at 35°C for 15 minutes. The treated paste was filtered and dried to obtain 50 g of metallic pigment.

(Comparative Example 1) 0.5 g of ultrafine iron oxide powder was added to 100 g of the aluminum paste shown in Example 1 (solid content 65%, solvent: methyl ethyl ketone), heated and stirred at 35° C. for 10 minutes, and then filtered and dried. Metallic pigment 4 which had a slightly red color due to
5g was obtained.

(Comparative Example 2) 7.2 g of ultrafine iron oxide powder was added to 100 g of the aluminum paste shown in Example 1 (solid content 65%, solvent: methyl ethyl ketone), heated and stirred at 30°C for 10 minutes, and then filtered and dried. 62g of metallic pigment with red color
I got it.

(Comparative Example 3) Stearic acid was used instead of the cationic dispersant (stearyldimethylbenzylammonium chloride) in Reference Example 1, and the same treatment as in Reference Example 1 was carried out to obtain an aluminum paste. The particle diameter measured by Microtrack was d=32.1 (μ).

(Comparative Example 4) 100 g of aluminum paste (solid content 65%, solvent: methyl isobutyl ketone) with a cationic dispersant adsorbed on its surface was coated with 0.0 g of titanium oxide ultrafine particle powder on which sodium sulfosuccinate was adsorbed. Add 4g and heat at 40℃ for 30 minutes.
The mixture was heated and stirred for a minute. By filtering and drying the treated paste, 60 g of metallic pigment was obtained.

(Margin below) [Comparison as metallic paint] (Preparation of resin) Methyl methacrylate 50%, n-butyl methacrylate 40%, ethylhexyl methacrylate 8%
, a mixture of 2% acrylic acid was copolymerized in toluene using a polymerization initiator azobisisobutylnitrile, heating residue 50%, resin viscosity Y (Gardner foam viscometer).
Acrylic resin A (25°C) was obtained.

(Cleavage of metallic paint) ■A mixture of acrylic resin and metallic pigment in the following ratio was shaken and dispersed in a paint shaker for 1 hour.
A metallic paint was made.

Acrylic resin A 160 parts Metallic pigment 15 parts Xylene 25 parts 200 parts Primary color paint Acrylic resin A 150 parts I made a blue primary color paint.

(2) Preparation A test paint was prepared by mixing the metallic paint (2) and the primary color paint (2) at a ratio of 10:1 (weight ratio).

(Effects of the Invention) As is clear from Tables 1 and 2, the metallic pigment of the present invention has excellent overall weather resistance including light resistance, alkali resistance, etc. compared to conventional metallic pigments. In addition, it was found that it has good dispersibility and exhibits excellent coating performance such as not producing lumps even when it is blended into a paint to form a coating.

Procedure amendment writing method) November 8, 1988

Claims (7)

[Claims] (1) A, metal powder with a particle size of 1.0 to 100μ with a cationic dispersant adsorbed on the surface, B, particle size 0.0 with an anionic dispersant adsorbed on the surface
Weather resistance characterized by the fact that the metal oxide ultrafine particle powder of 1 to 0.1μ is used, and the ratio of A and B is A/B = 100/1 to 10, and B is coordinated to the surface of A by an ionic reaction. A good method for producing metallic pigments. (2) The amount of cationic dispersant used is 0 relative to the metal powder.
．． 5wt% to 5wt%, and the amount of anionic dispersant used is 1wt% to 5wt with respect to the metal oxide ultrafine particle powder.
% of the metallic pigment according to claim 1. (3) Metal powder is aluminum, copper, brass, chromium,
3. The method for producing a metallic pigment according to claim 1 or 2, wherein the pigment is nickel, cobalt, stainless steel, or the like. (4) Claim 1 in which the metal powder is limited to aluminum
A method for producing a metallic pigment according to item 1 or 2. (5) The method for producing a metallic pigment according to claim 1 or 2, or 3 or 4, wherein the metal oxide ultrafine particle powder is limited to titanium oxide and iron oxide. (6) The main chain is made of a vinyl polymer containing a silyl group, and is coated with a synthetic polymer compound that has at least one silicon group in each molecule bonded to a hydrodispersible group at the molecular end or side chain. A method for producing a metallic pigment according to claim 1, 2, 3, 4, or 5. (7) A paint containing the metallic pigment according to claim 1 or 2 or 3 or 4 or 5 or 6.