JPH0610276A - Production of colored fine particle - Google Patents

Abstract

PURPOSE:To produce fine particles useful as fine particles for a colorant or a matting agent having excellent clarity of color fade resistance and solvent resistance. CONSTITUTION:An aqueous solution of uncured guanamine-based resin is mixed with one or mare dyes selected from vat dye, sulfur dye and sulfur vat dye, reduced, cured and oxidized to produce colored fine particles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing colored fine particles, which provides fine particles useful as a coloring agent or a matting agent which are excellent in color vividness, color migration resistance and solvent resistance. It is a thing.

[0002]

2. Description of the Related Art Heretofore, organic or inorganic pigments have been used as coloring paints and matting agents. However, it is inferior to the one dyed with a dye in terms of color clarity. As a matting agent, fine powder of silicon oxide (silica) has been used so far, but when it is used for chromatic or black matting, it is not clear and whitish and only poor quality is obtained. It was

[0003]

SUMMARY OF THE INVENTION The present invention is a conventional pigment,
The purpose is to produce new colored fine particles that have improved the lack of color sharpness that a matting agent had.

[0004]

According to the present invention, one or more dyes selected from the group consisting of sulfur dyes, vat dyes, and sulfur vat dyes are added to an uncured guanamine-based resin aqueous liquid and subjected to reduction treatment. The method for producing colored fine particles is characterized in that a color is developed by performing a curing treatment and an oxidation treatment.

For the purpose of producing a pigment having a clear color of a dye, an attempt has been made to produce a resin colored with a dye by finely pulverizing the resin. The thing which solved the problem such as the crying out of the dye in the solvent was not obtained. A guanamine-based resin is known as fine particles having excellent water resistance, solvent resistance, heat resistance, and the like, and a method of coloring this with a dye is disclosed in Japanese Patent Publication No. 59-48007. The dyes used are water-soluble and the dyes used have insufficient light resistance, water resistance and solvent resistance. As a result of investigating a method for producing colored fine particles in which these drawbacks are improved, a sulfur dye, a vat dye or a sulfur vat dye which becomes water-soluble in an alkaline reducing state is used as a component to be colored, and an uncured guanamine which is uncured in a reducing state is used. It has been found that this can be achieved by treating the system resin with water and insolubilizing it before or after the curing reaction, or during or after the curing reaction.

The guanamine-based resin used in the present invention is generally obtained by reacting a guanamine derivative with formaldehyde, but is not limited to a specific synthesis method. Although some synthesis methods of guanamine derivatives are known, a synthesis method from dicyandiamide and a nitrile compound is general.

As specific examples of guanamine derivatives, acetoguanamine, propyloguanamine, benzoguanamine, tolylguanamine, phenylacetoguanamine, octanoguanamine, oleoguanamine, stealoganamine and the like are known. Acetoguanamine and benzoguanamine are preferable for the purpose of producing colored fine particles satisfying water resistance and solvent resistance.

The uncured guanamine-based resin aqueous solution can be prepared by a known method, but a sulfur dye, vat dye, or sulfur vat dye in a reduced state is added to the guanamine-based resin aqueous solution under alkaline conditions. Since it is necessary to treat, the protective colloid agent that disperses the uncured guanamine-based resin at the time of the effect reaction needs to be selected from those having no affinity with the dye in the reduced state, for example, a hydroxyl group, a carboxyl group, and an amino group. It is necessary to avoid those containing a group having a high affinity with the dye. Specifically, it is sodium polyacrylate, high molecular weight polyethylene glycol, or the like.

The uncured guanamine-based resin is dispersed in these protective colloid agents, and then the above dye solution in an alkali reduced state is added to adsorb the reduced dye molecules to the guanamine-based resin. Sulfur dyes, vat dyes, and sulfur vat dyes can be reduced by using hydrosulfite, sodium sulfoxylate formaldehyde, sodium sulfide, or sulfide as a reducing agent in an alkaline liquid such as sodium hydroxide or sodium carbonate. A sulfur dye, a vat dye, and a sulfur vat dye are added to an aqueous solution in which a reducing agent such as potassium and thiourea dioxide is dissolved to make it water-soluble. The condition for treating the guanamine resin with the dye in the reduced state is that the temperature is gradually raised from room temperature, and is usually 60 to 90 ° C. for 20 to 60 minutes. It should be noted that if the temperature is too high, the dye may become overreduced and some dyes may become insoluble in water.

In order to carry out a curing reaction and an oxidation treatment after treating the dye in the alkali reduced state, mineral acids such as hydrochloric acid, sulfuric acid and phosphoric acid, carboxylic acids such as acetic acid, benzoic acid and phthalic acid, benzenesulfonic acid, The pH is adjusted to 2 to 5 by neutralizing with sulfonic acid such as paratoluene sulfonic acid and then adding these acids in excess. Then, the dye is subjected to an oxidation treatment to make it insoluble in water, and is treated by using hydrogen peroxide, sodium perborate, potassium permanganate or the like as an oxidizing agent. The oxidation condition is 20 to 60 ° C. for 5 to 60 minutes.
When the treatment is performed at a high temperature for a short time, only the dye molecules near the surface layer are oxidized, so it is necessary to take some time to sufficiently oxidize the dye inside.

In order to use the cured fine particles as a colorant and a matting agent, the size of the fine particles after curing is preferably 30 μm or less, and most preferably 0.01 to 10 μm. When the size of the particles is 30 μm or more, when it is kneaded into a paint as a colorant or a matting agent, the particles are too large and dispersion stability and coating uniformity are deteriorated, which is not preferable.

A detailed description will be given below based on embodiments.

[0013]

Example 1 187.5 g of benzoguanamine, 162.5 g of formalin (concentration 37%), 0.06 sodium carbonate were placed in a reaction vessel equipped with a stirrer, a condenser and a thermometer.
5 g was reacted at a charging temperature of 94 to 96 ° C. for 6 hours. While stirring 750 g of a 10% aqueous solution of sodium polyacrylate (Matsumoto Yushi-Seiyaku Co., Ltd. Marposol S200) with a mixer at high speed, a solution containing the reaction product was dropped little by little to prepare an aqueous liquid. Then, a reducing solution of a sulfur dye was prepared under the following conditions. Dye; Asaciozole black SBC 12g Reducing agent; Hydrosulfite soda 10g Sodium hydroxide 2g Water 250g Reduction conditions; Temperature 40 ° C x hour 30 minutes Next, stir the reducing solution of the sulfur dye in the uncured guanamine aqueous solution prepared above. Add while carrying out 30 while adjusting to 40 ℃
Processed for a minute. Next, this solution was neutralized with a sulfuric acid aqueous solution, and excess sulfuric acid was further added to adjust the pH to 3. Next, 4 g of hydrogen peroxide solution (concentration 35%) was added and treated at 40 ° C. for 30 minutes, and then a curing reaction was performed while raising the temperature from 40 ° C. to 90 ° C. at a rate of about 10 ° C./2 hours. A suspension of The colored fine particles are filtered off and dried at 100 ° C., 150
It was heat-treated at ℃ for 3 hours and ground in a ball mill to obtain colored fine particles. The average particle size of the obtained fine particles was 3 microns.

Next, using the obtained fine particles, a polyurethane elastomer paint having the following composition was prepared. Harauuk A-3454 (20%) 100 parts by weight Toluene / methyl ethyl ketone (1: 1) 100 parts by weight Colored fine particles 20 parts by weight A leather-like sheet base material prepared in Japanese Patent Publication No. 57-27232 and the like has a polyurethane elastomer of the following composition. 20 g / m ^{2 of} paint in gravure coater, calculated as resin solids
A coated sheet was prepared. Harauk A-1003 (20%) 100 parts by weight Toluene / methyl ethyl ketone (1: 1) 100 parts by weight Carbon black 20 parts by weight Furthermore, the coating composition obtained by adding the coloring fine particles of the present invention to the surface of this sheet is converted into a solid content by a gravure coater. 7 g / m ^{2 was} applied. The obtained sheet was a matte sheet having an excellent blackness and had an excellent appearance as a leather-like sheet, and was excellent in fastness to wet rubbing and light resistance, and was free from color bleeding due to an adhesive solvent.

[0015]

Comparative Example 1 Colored fine particles were prepared by using a metal-containing complex salt dye instead of the sulfur dye used in Example 1. Example 1
187.5 g of benzoguanamine, 162.5 g of formalin (concentration 37%), sodium carbonate of 0.
065 g was reacted at a charging temperature of 94 to 96 ° C. for 6 hours. After that, 9.375 g of Kayaset Black 2RL was added and the mixture was stirred at 30 ° C. for 30 minutes while keeping the temperature at 94 to 96 ° C. to make the dye compatible with the reaction product.

Next, a 1% aqueous solution of polyvinyl alcohol was stirred with a mixer to add a solution containing the above reaction product to obtain a colored uncured reaction product. Then, p-toluenesulfonic acid was added to adjust to PH3, and then the temperature was sequentially increased from 40 ° C. to 90 ° C. and reacted for 10 hours. The colored fine particles obtained are filtered off and dried at 100 ° C.
It heat-processed at 0 degreeC for 3 hours, and grind | pulverized in the ball mill.

A leather-like sheet was prepared from the obtained fine particles by the same method as in Example 1 and compared with Example 1. The appearance was similarly excellent, but the wet fastness and solvent for adhesive ( Color bleeding with toluene, methyl ethyl ketone, etc.) was observed.

Claims (1)

[Claims] 1. An uncured guanamine-based resin aqueous liquid is added with one or more dyes selected from the group consisting of sulfur dyes, vat dyes, and sulfur vat dyes, and subjected to reduction treatment, followed by curing treatment and oxidation treatment. A method for producing colored fine particles, which comprises: