JPH04211450A - Fine spherical particle of colored resin and its production - Google Patents

Abstract

PURPOSE:To provide fine spherical particles of colored resin having excellent heat-resistance, solvent resistance and chemical resistance, capable of taking a truly spherical form, exhibiting sufficiently satisfactory durability and coloring power and advantageously usable for industrial purpose. CONSTITUTION:The objective spherical fine particle of colored resin is composed of a cured amino resin integrated to carbon black used as an inorganic pigment. The ratio of the carbon black to the sum of the cured amino resin and the carbon black is 1-30wt.%.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention is applicable to colorants for paints, inks, plastics, fibers, rubber, etc., matting agents, fillers, toners and carriers for electrostatic copying machines, and colorants used in cosmetics, etc. This invention relates to resin spherical fine particles. More specifically, it is made by integrating a cured amino resin and an inorganic pigment.
The present invention relates to new industrially useful colored resin spherical fine particles and a method for producing the same.

0002

BACKGROUND OF THE INVENTION Hitherto, various colored resin spherical particles have been used in plastics, paints, inks, cosmetics, etc., and each has its own unique way of being used. The colored resin spherical fine particles are made by integrating a dye or a pigment with a resin. In this way, dyes and pigments are not used as they are, but are integrated with resin and used in paints,
This is because it improves compatibility with polymers such as inks, plastics, fibers, and rubber. In addition, if the particles are spherical, compared to non-spherical particles, the fluidity during molding will be improved, and when used in paints, fibers, etc., the surface will be smoother and the amount of filling can be increased. There are advantages.

Colored resin spherical fine particles obtained by combining thermosetting resins such as phenol resins and epoxy resins, or thermoplastic resins such as acrylic resins and vinyl resins, and organic dyes or organic pigments have excellent clarity and coloring power. On the other hand, it tends to be inferior in heat resistance, light resistance, solvent resistance, weather resistance, color bleeding resistance, etc. On the other hand, colored resin spherical fine particles using inorganic pigments for coloring are superior to those using dyes in terms of solvent resistance, light resistance, heat resistance, and color bleeding resistance. In this respect, it is superior to those using organic pigments.

[0004] Colored resin fine particles obtained by coloring a thermoplastic resin with a pigment include, for example, colored resin fine particles obtained by mixing and pulverizing a thermoplastic resin and a pigment (JP-A-58-1
7169), colored resin spherical fine particles obtained by adding a pigment during a reaction such as suspension polymerization (Japanese Patent Publication No. 57-2232)
4), colored resin spherical fine particles obtained by applying a chemical or physical treatment to the surface of thermoplastic resin fine particles and then coating them with a pigment (Japanese Unexamined Patent Publication No. 10671/1983) are known. .

[0005] Colored resin spherical fine particles made of a thermosetting resin colored with a pigment include, for example, a pigment added when a thermosetting resin such as a phenol resin or an epoxy resin is synthesized by polyaddition or addition condensation. Colored thermosetting resin spherical fine particles obtained by this method are known.

[0006]

[Problems to be Solved by the Invention] Conventional colored resin fine particles using the above-mentioned thermoplastic resin have poor heat resistance, solvent resistance, chemical resistance, etc., poor adhesion between the resin particles and pigment, and coloring. There are problems such as poor particle surface smoothness. In addition, conventional colored resin spherical fine particles using the above-mentioned thermosetting resin have a wide particle size distribution, the particle shape is not true spherical fine particles, and the particles are brittle, which may require classification etc. Therefore, there are problems such as increased costs.

The present invention solves the problems of the colored resin spherical fine particles obtained by the above-mentioned conventional technology, and the spherical fine particles have excellent heat resistance, solvent resistance, and chemical resistance, and can be made into true spheres. It is an object of the present invention to provide industrially advantageous colored resin spherical fine particles that can be used in the manufacturing process and that are sufficiently satisfactory in terms of durability and coloring power, as well as a method for producing the same.

[0008]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a method in which a cured amino resin product and an inorganic pigment are integrated, and the ratio of the inorganic pigment to the total amount of the cured amino resin product and the inorganic pigment is 1. -30% by weight (hereinafter, "%" means "% by weight" unless otherwise specified) colored resin spherical fine particles are provided.

[0009] The present invention also provides a method in which an amino resin and an inorganic pigment are mixed, emulsified, and polycondensed in an emulsified state, so that the ratio of the pigment to the total amount of the cured amino resin product and the inorganic pigment is 1 to 30%. To provide a method for producing colored resin spherical fine particles that integrates an amino resin cured product and an inorganic pigment so as to achieve the following. In this invention, the ratio of the inorganic pigment to the total amount of the cured amino resin product and the inorganic pigment must be 1 to 30%. If the proportion of inorganic pigment is less than this range, there is a problem that the coloring properties of the colored resin spherical fine particles are insufficient, and if it is too large, the entire amount of inorganic pigment cannot be fixed to the amino resin, the particles will have a distorted shape, and the particle size distribution will also be affected. The problem is that it becomes wider. Further, by using an amino resin, there is an advantage that colored resin spherical particles having excellent heat resistance, solvent resistance, and chemical resistance can be produced.

The colored resin spherical fine particles of the present invention are produced, for example, as described below, so that the inorganic pigment and the cured amino resin are integrated. As a result, the spherical fine particles are colored with the inorganic pigment. The colored resin spherical fine particles of this invention are spherical, for example, when the particle diameter ratio (major axis/breadth axis) determined from electron microscopic images of 200 colored resin spherical fine particles is in the range of 1.0 to 1.25. belongs to.

[0011] The amino resin in this invention is an amino compound having two or more amino groups in the molecule, for example,
A resin obtained by polycondensation reaction of formaldehyde and one or more amino compounds selected from the group consisting of urea, melamine, benzoguanamine, cyclohexanecarboguanamine, cyclohexenecarboguanamine, norbornanecarboguanamine, norbornenecarboguanamine, etc. It may be present, and may be etherified with alcohol. As described below, when using treated carbon black (hereinafter, "carbon black" may be referred to as "CB"), the amino resin is selected from benzoguanamine, cyclohexanecarboguanamine, and cyclohexenecarboguanamine. It is preferable to use an initial reaction product (precondensate) obtained by polycondensing an amino compound containing 40 to 100% of at least one type of guanamine with formaldehyde, and may be etherified. When using treated CB, it is preferable to use such an amino resin because it has good affinity with the treated CB and allows the CB to be uniformly dispersed.

[0012] As the amino resin used in this invention, an amino resin initial reaction product having a methanol miscibility of 400% or less is preferable. The methanol miscibility of the initial reactant refers to the degree of polycondensation of the amino resin, and is the amount of water required to dissolve 2 g of the initial reactant in 5 g of methanol and add water dropwise while keeping the temperature at 25°C to produce a cloudy state. It is the value obtained by multiplying the ratio of the weight to the weight of the initial reactant by 100.

[0013] The inorganic pigment used in the present invention is not particularly limited in type or shape, and examples thereof include titanium oxide, iron oxide, zinc oxide, barium sulfate, calcium sulfate, barium carbonate, calcium carbonate, magnesium carbonate, talc, and clay. , carbon black, etc. are used, and if necessary, the particles are processed with a grinder such as a ball mill to improve coloring properties (improve dispersibility in resin, etc.). The diameter is preferably 5 μm or less, more preferably 0.1 μm or less. By using an inorganic pigment, the colored resin spherical fine particles have concealing properties. By using such colored resin spherical fine particles, it is possible, for example, to prevent the color of the fabric (or base) from coming out or to color it so that it does not blend into other colors.

In the present invention, the amount of inorganic pigment used is such that the amount of inorganic pigment contained in the colored resin spherical fine particles is 1 to 30%, preferably 5 to 20%, based on the total amount of the cured amino resin product and inorganic pigment. The ratio may be set as appropriate. In order to achieve such a ratio, it varies depending on the type of amino resin, the type of inorganic pigment, etc., but for example, the amount of inorganic pigment used is 0.00% for the total amount of amino resin and inorganic pigment used.
Used in proportions of 9-27%.

The inorganic pigment used in the present invention may be surface-treated to improve its dispersibility in the amino resin. Furthermore, at least one of a dye and an organic pigment may be used as an auxiliary agent. In particular, CB is
If it is in a form treated with a compound (A) that has reactivity and/or affinity with the functional group present on the surface of B, it will have good dispersibility in the initial reaction product of the amino compound and formaldehyde, and the degree of coloration will increase. It is possible to obtain black resin spherical fine particles having excellent properties.

The compound (A) is a compound having a reactive group and/or affinity that can easily react with a functional group (for example, -OH, -COOH, -C=O, etc.) present on the surface of CB. If so, it can be used without any particular restriction. Compound (A) is, for example, a monomer or polymerizable monomer having one or more of an aziridine group, an oxazoline group, an N-hydroxyalkylamide group, an epoxy group, a thioepoxy group, an isocyanate group, a hydroxyl group, an amino group, an imino group, etc. It may be a monomer, or it may be one obtained by polymerizing one or more polymerizable monomers according to known procedures, if necessary. Specific examples of compound (A) include polyethylene imine with an average molecular weight of 300 to 100,000, polyethylene glycol glycidyl ether with an average molecular weight of 700,000 to 100,000, and (
Poly)alkylene glycol, etc. Compound (A)
To process CB, for example, do as follows. The CB and the compound (A) are sufficiently kneaded using various kneaders and raised to a certain temperature to improve the reactivity or affinity between the functional groups on the CB surface and the functional groups of the compound (A).

The emulsifier used in this invention may be any emulsifier that forms a protective colloid, such as polyvinyl alcohol, polyvinylpyrrolidone, carboxymethyl cellulose, alkali metal salts of polyacrylic acid, and styrene-maleic acid copolymers. Alkali metal salts and the like are used, among which polyvinyl alcohol is particularly preferred. Emulsification using an emulsifier in this invention is
Either add the emulsifier directly to the mixture of a predetermined amount of inorganic pigment in the amino resin, or prepare a separate aqueous solution of the emulsifier and add the mixture of the amino resin and inorganic pigment to the mixture to make the liquid strong. This can be carried out by stirring using a stirrer that provides a suitable shearing force, such as a colloid mill, a disper mill, a homomixer, a homogenizer, etc. The amino resin used in the above emulsification process is
The initial reactant has a methanol miscibility (an indicator of the degree of polycondensation) of 400% or less, and more preferably 200% or less. By decreasing the methanol miscibility, the particle size increases, and by increasing the methanol miscibility, the particle size decreases. When the methanol miscibility is greater than 400%, the hydrophilicity becomes too large, making it difficult to obtain monodispersed particles. The degree of condensation of the initial reactant of the amino resin can be controlled by methanol miscibility as described above, but it can also be controlled by GPC (gel permeation chromatography), LC (liquid chromatography), acetone miscibility, etc. Among these, it is preferable to control the degree of miscibility with acetone from the viewpoint of operability, reproducibility, etc. Acetone miscibility refers to the degree of polycondensation of amino resin,
This is the value obtained by multiplying 100 by the weight ratio of the weight of water required to produce cloudiness by dissolving 2 g of the initial reactant in 5 g of acetone and adding water dropwise while maintaining the temperature at 25° C. and the weight of the initial reactant. The acetone miscibility of the initial reactant is preferably 50 to 500%,
More preferably it is 100-300%. If the acetone miscibility exceeds 500%, it becomes difficult to obtain particles;
If it is smaller than %, it becomes difficult to form spherical fine particles.

[0018] The amount of emulsifier added is 1 to 1 to the amino resin.
A range of 30% is preferred, and a range of 2 to 10% is more preferred. By increasing the amount of emulsifier used, the particle size can be reduced, and by decreasing the amount used, the particle size can be increased. If the amount of emulsifier added is less than 1%, emulsification may not be possible;
If it exceeds this, it may become difficult to separate the fine particles obtained by curing as single particles. In addition, by increasing the stirring efficiency, the particle size becomes smaller, and by lowering the stirring efficiency, the particle size becomes larger. This is because increasing or decreasing the stirring efficiency to achieve an emulsified state is related to the magnitude of the force shearing the initial reactants. By appropriately selecting the polycondensation rate of the amino resin, the amount of emulsifier, the stirring efficiency, etc., it is possible to arbitrarily synthesize colored resin spherical fine particles that are perfectly spherical, have a narrow particle size distribution, and have a target particle size. The colored resin spherical fine particles of this invention are truly spherical when the particle diameter ratio (major axis/breadth axis) determined from electron microscopic images of 200 colored resin spherical fine particles is in the range of 1.0 to 1.1. It is something.

The curing catalyst used in the present invention is a polycondensation catalyst for amino resins, and includes, for example, mineral acids such as hydrochloric acid, sulfuric acid, and phosphoric acid; benzoic acid, phthalic acid, acetic acid, propionic acid,
Carboxylic acids such as salicylic acid; ammonium salts such as ammonium chloride and ammonium phosphate; and sulfonic acids such as benzenesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, etc. One or more types may be appropriately selected and used. can. The curing catalyst is a solid content of an uncured amino resin emulsion colored with an inorganic pigment (
However, pigments are excluded), preferably from 0.01 to
10% (0.01-5 when using treated CB)
%), more preferably 0.2-5% (treated CB
When using, it is used in the range of 0.2 to 2%). If the amount of curing catalyst added is too large, the emulsified state may be destroyed and aggregates may be formed, and if the amount added is too small, curing may be insufficient or curing may take a long time. Undesirable. For example, curing is 10~
After holding at a temperature in the range of 200°C for at least 1 hour,
Curing is carried out at a temperature in the range of 40 to 200° C. under normal pressure or increased pressure, and curing is completed when the cured product becomes insoluble in acetone, methanol, methyl ethyl ketone, dioxane, dimethylformamide, etc.

After the curing reaction is completed, the colored resin spherical fine particles may be separated by any known method, including various separation methods such as natural sedimentation, centrifugal sedimentation, separation by decantation, and separation by filtration. Can be freely adopted. In addition, the colored resin spherical fine particles obtained by separation are mixed with water and various organic solvents, for example, nonpolar solvents such as toluene and xylene, polar solvents such as methyl ethyl ketone, methanol, ethanol, isopropyl alcohol, dimethylformamide, and tetrahydrofuran. By dispersing it in a mixed solvent consisting of these, it can be obtained as a paste or dispersion. After the separation operation, the colored resin spherical fine particles can be dried by a conventionally known method such as natural drying, reduced pressure drying, or hot air drying. After the drying operation, heat treatment at a temperature of 100 to 200°C further improves the heat resistance, water resistance, solvent resistance, etc. of the desired colored resin spherical fine particles, so if necessary, such heating may be performed. It is preferable to perform treatment. However, if the drying process is performed at a relatively high temperature, heat treatment is performed at the same time.
In such a case, heat treatment may not be performed. The dried colored resin spherical fine particles are crushed by applying a force to break up the agglomeration using a crusher such as a ball mill, hammer mill, jet mill, etc., and a fine powder of colored resin spherical fine particles can be obtained. Furthermore, it is of course possible to disperse the colored resin spherical fine particles after the drying operation in a solvent to form a paste or a dispersion.

When the colored resin spherical fine particles of the present invention are produced, for example, by polycondensation in an emulsified state,
．． Although it has an average particle diameter in the range of 1 to 50 μm, it may have an average particle diameter outside this range. In addition,
In this invention, polycondensation in an emulsified state refers to polycondensation in a state where droplets are dispersed in a dispersion medium, and is not limited to emulsion polymerization, but may also include suspension polymerization. include.

[0022]

[Examples] Specific examples and comparative examples of the present invention are shown below, but the present invention is not limited to the following examples. Table 1 shows the synthesis conditions of Examples 1 to 6 and Comparative Examples 1 to 4. - Example 1 - In a flask equipped with a stirrer, a reflux condenser and a thermometer, 150 g (0.8 mol) of benzoguanamine, 162 g (2.0 mol formaldehyde) of formalin with a concentration of 37% and 0.0 g of an aqueous solution of sodium carbonate with a concentration of 10%. 65g was charged and reacted for 5 hours at a temperature of 94 to 95°C with stirring, resulting in methanol miscibility of 60% and acetone miscibility of 25%.
0% initial reactant was obtained. To this initial reaction product, 20 g of titanium oxide (TA-100 manufactured by Fuji Titanium Co., Ltd.) was added and stirred for 30 minutes to obtain an initial reaction product colored white by titanium oxide. Separately, an aqueous solution obtained by dissolving 10.5 g of Kuraray Poval 205 (polyvinyl alcohol partial hydrolyzate manufactured by Kuraray Co., Ltd.) in 145 g of water was prepared at 90%
After raising the temperature to .degree. C., the mixture was stirred at 6000 rpm using a homomixer (Model M, manufactured by Tokushu Kikako Co., Ltd.). The white colored initial reaction product was added to the Kuraray Poval aqueous solution under stirring to obtain a white emulsion. This emulsion was cooled to 40°C, then 4.5g of dodecylbenzenesulfonic acid was added, and the temperature was gradually raised to 50°C, 70°C, and 80°C.
The mixture was heated and stirred for 2 hours at each temperature in order to obtain a suspension of colored resin spherical particles cured by polycondensation in an emulsified state. When this suspension was observed under an optical microscope (600x magnification), it was found that it consisted of spherical fine particles with a particle diameter of about 4 μm. Colored resin spherical fine particles are separated from the suspension by filtration, washed with water, dried at 100°C for 1 hour, then heated at 150°C for 3 hours, and then lightly crushed in a mortar to obtain colored resin spherical particles with a clear white color. A fine particle powder was obtained.

When observing an electron microscope image of 200 fine particles of the colored resin spherical fine particles thus obtained using a scanning electron microscope (model S-570 manufactured by Hitachi, Ltd.), it was found that the particle size ratio (major axis/breadth axis) was 1. .05, and no unparticulated titanium oxide could be observed, indicating that most of the added titanium oxide was dispersed in the colored resin spherical fine particles. The particle size of the colored resin spherical fine particles was measured using a Coulter counter (TA-2 manufactured by Coulter).
The average particle diameter was 4.25 μm, and the particle size distribution was very sharp. Further, the colorability, heat resistance, dispersibility, and water resistance of the colored resin spherical fine particles were investigated as follows. The colored resin spherical fine particles were white resin spherical fine particles having excellent colorability, heat resistance, dispersibility, and water resistance. The results are shown in Table 2.

The colorability was evaluated by comparing the hue of the pigment used and the colored resin fine particles obtained using a color difference meter, and evaluating the degree of coloration according to the following criteria. Good: The color difference between the inorganic pigment alone and the colored resin fine particles is within 10%. Δ: The color difference between the inorganic pigment alone and the colored resin fine particles is more than 10% and less than 20%.

×: The color difference between the inorganic pigment alone and the colored resin fine particles is 20% or more. Heat resistance is according to JIS K-5101 (16).
After treatment at 180° C. for 2 hours, changes in shape were examined and evaluated using the following criteria. ○: After the heat resistance test, the particle size ratio was determined and the difference in particle size ratio was less than 10% compared to the untreated product.

×: After the heat resistance test, the particle size ratio was determined and the difference in particle size ratio was 10% or more compared to the untreated product. Dispersibility is determined according to JIS K-5101 (7) by thoroughly kneading 20 g of printing varnish and 5 g of colored resin fine particles, and then using a grind meter to find groove marks equivalent to three times the average particle diameter of the powder. It was investigated and evaluated using the following criteria.

Pass: There are less than 3 lines in the trace. Fail: There are three or more lines in the trace. Water resistance is according to JIS K-5101 (12).
Approximately 0.5 g of colored resin particles were placed in a glass test tube, 10 ml of water was added, and the mixture was heated to 95° C., then allowed to cool, and the hue of the supernatant liquid was examined and evaluated according to the following criteria.

[0028] Colorless and transparent: There is no desorption of the pigment from the colored resin fine particles, so water resistance is good. Slight cloudiness: Poor water resistance due to desorption of pigment from colored resin particles. Pale black: Poor water resistance due to detachment of pigment from colored resin fine particles. - Examples 2 to 4 and Comparative Examples 1 to 3 - Coloring was performed in the same manner as in Example 1 except that the resin concentration, pigment concentration, emulsifier amount, and stirring speed were set to the conditions listed in Table 1. Resin spherical fine particles were obtained.

The results are shown in Table 2. -Example 5- In Example 1, Fe3 O4 (
Colored resin spherical fine particles were obtained in the same manner as in Example 1 except that 20 g of spinel type (manufactured by Mitsubishi Metals Co., Ltd.) was used.

The colored resin spherical fine particles have an average particle diameter of 5.
The black resin spherical fine particles had a diameter of 11 μm (Coulter counter value), were perfectly spherical as in Example 1, and had excellent colorability, heat resistance, dispersibility, and water resistance. The results are shown in Table 2. - Example 6 - In a flask equipped with a stirrer, a reflux condenser and a thermometer, 112 g (0.6 mol) of benzoguanamine and 25 g of melamine were added.
g (0.2 mol), 145 g of formalin with a concentration of 37% (
1.8 mol of formaldehyde) and 0.65 g of a 10% sodium carbonate aqueous solution were added, and the
The reaction was carried out at a temperature of 4 to 95° C. for 6 hours to obtain an initial reactant with a methanol miscibility of 35% and an acetone miscibility of 150%. To this initial reaction product, 15 g of carbon black (MA600 manufactured by Mitsubishi Kasei Corporation) was added and stirred for 30 minutes to obtain an initial reaction product colored black with carbon black. Separately, an aqueous solution obtained by dissolving 7.5 g of Kuraray Poval 205 (polyvinyl alcohol partial hydrolyzate manufactured by Kuraray Co., Ltd.) in 140 g of water was heated to 90°C, and then a homomixer (M type manufactured by Tokushu Kikako Co., Ltd.) was heated. ) and stirred at 6000 rpm. The black colored initial reactant was added to the Kuraray Poval aqueous solution under stirring to obtain a black emulsion. This emulsion was cooled to 40°C, then 4.1 g of dodecylbenzenesulfonic acid was added, the temperature was gradually raised, and the emulsion was heated and stirred at each temperature of 50°C, 70°C, and 90°C for 2 hours in turn, until the emulsified state A suspension of colored resin spherical fine particles polycondensed and cured was obtained. When this suspension was observed under an optical microscope (600 times magnification), it was found that it consisted of spherical fine particles with a particle diameter of about 6 μm. Colored resin spherical fine particles were filtered from the suspension, washed with water, and incubated at 100°C for 1
After drying for an hour and then heat-treating at 150° C. for 5 hours, the powder was lightly crushed in a mortar to obtain a powder of colored resin spherical fine particles having a clear black color.

When observed with a scanning electron microscope, the colored resin spherical fine particles thus obtained were true spherical fine particles with a particle diameter ratio (major axis/minor axis) of 1.06, and were found to be fine spherical particles that had not been granulated. was not observed, indicating that most of the added carbon black was dispersed within the colored resin spherical fine particles. When the particle size of the colored resin spherical fine particles was measured using a Coulter counter, the average particle size was 5.87 μm and the particle size distribution was also very sharp. Further, the colored resin spherical fine particles were black resin spherical fine particles having excellent colorability, heat resistance, dispersibility, and water resistance. The results are shown in Table 2.

- Comparative Example 4 - In a flask equipped with a stirrer, a reflux condenser, and a thermometer, 2 g of acrylic acid, 240 g of methyl methacrylate, 29 g of divinylbenzene, 50 g of styrene resin, 1 g of azobisisobutyronitrile, and carbon black (Mitsubishi Chemical Co., Ltd.) were added. 25 g of MA600 (manufactured by Co., Ltd.) was charged and sufficiently stirred to mix uniformly to obtain a black solution. Separately Kuraray Poval 20
An aqueous solution obtained by dissolving 17 g of 5 (polyvinyl alcohol partial hydrolyzate manufactured by Kuraray Co., Ltd.) in 600 g of water was mixed with N2 using a homomixer (Model M manufactured by Tokushu Kikako Co., Ltd.).
The mixture was stirred at 6000 rpm under atmosphere. After adding the above black solution to the Kuraray Poval aqueous solution under stirring,
The temperature was raised to ℃. After raising the temperature for 30 minutes, transfer to a four-necked flask.
2. The polymerization reaction was allowed to proceed for 5 hours while heating and stirring at 80° C. in an atmosphere to obtain a suspension of a cured resin colored black. When this suspension was observed under an optical microscope (600 times magnification), it was found that it consisted of spherical fine particles with a particle diameter of about 6 μm. After filtering the cured resin from the suspension and washing with water,
By drying at ℃ and crushing in a mortar, a black powder of cured resin spherical fine particles was obtained. When the thus obtained cured resin spherical fine particles were observed with a scanning electron microscope, they were spherical fine particles with a particle size ratio (major axis/breadth axis) of 1.12, and non-particulate carbon black was observed.

[0033] When the particle size of the resin spherical fine particles was measured using a Coulter counter, the average particle size was 6.23 μm.
m, the particle size distribution was broad. Furthermore, the resin spherical fine particles had poor colorability, dispersibility, and water resistance. The results are shown in Table 2. Table 1 shows Examples 1 to 6 and Comparative Example 1.
-4 synthesis conditions are shown.

[0034]

[Table 1]

[0035]

[Table 2]

As shown in Table 2, the colored resin spherical fine particles of Examples were spherical and had excellent colorability, dispersibility, water resistance, and heat resistance. On the other hand, in Comparative Example 1, the pigment ratio was too high, resulting in poor dispersibility and water resistance, and in Comparative Example 2, the pigment ratio was too low, resulting in poor coloring properties. In Comparative Example 3, spherical fine particles were not obtained. this is,
This is because polycondensation was not performed in an emulsified state. Comparative example 4
Since a cured acrylic resin was used instead of a cured amino resin, colorability, dispersibility, water resistance, and heat resistance were all poor.

Next, examples and comparative examples will be shown in which carbon black treated as an inorganic pigment is used in the present invention, but the present invention is not limited to the following examples. First, an example of processing carbon black will be shown. -Reference Example 1- 100 parts by weight of MA-600 (manufactured by Mitsubishi Kasei Co., Ltd.) as a CB and Epomin SP-300 (Nippon Shokubai Chemical Co., Ltd.), which is a polyethyleneimine with a molecular weight of 30,000, were added to Laboplastomil (manufactured by Toyo Seiki Co., Ltd.). made) 200
Parts by weight were added, kneaded for 20 minutes at a temperature of 100 to 200° C. with stirring, and then cooled to obtain treated carbon black. This is called CB(1).

-Reference Example 2- In Reference Example 1, Denacol EX, which is lauryl alcohol polyethylene glycol glycidyl ether with a molecular weight of 902, was used instead of 200 parts by weight of polyethyleneimine.
Carbon black treated in the same manner as in Reference Example 1 was obtained, except that 100 parts by weight of -171 (manufactured by Nagase Chemical Industries, Ltd.) was used. This is called CB(2).

-Reference Example 3- Same as Reference Example 1 except that 100 parts by weight of PEG1000 (manufactured by Kanto Kagaku Co., Ltd.), which is a polyethylene glycol with an average molecular weight of 1000, was used instead of 200 parts by weight of polyethyleneimine. Carbon black treated in the same manner was obtained. This is called CB(3).

Table 3 shows Examples 7 to 17 and Comparative Example 5,
The synthesis conditions of 6 are summarized below. - Example 7 - In a four-necked flask equipped with a stirrer, a reflux condenser and a thermometer, 187 g (1.0 mol) of benzoguanamine, 25 g (0.2 mol) of melamine, and 24 formalin at a concentration of 37% were added.
3g (3.0 moles of formaldehyde) and concentration 10%
0.95 g of an aqueous sodium carbonate solution was charged and reacted for 3 hours and 30 minutes at a temperature of 94 to 95° C. with stirring to obtain an initial reaction product having a methanol miscibility of 60% and an acetone miscibility of 250%. CB obtained in Reference Example 2 to this initial reaction product
(2) Add 67.1g, stir for 30 minutes,
An initial reaction product colored black was obtained. Separately, an aqueous solution obtained by dissolving 15.9 g of Kuraray Poval 205 (polyvinyl alcohol partial hydrolyzate manufactured by Kuraray Co., Ltd.) in 183 g of water was heated to 90°C, and then a homomixer (HW-M, Tokushu Kikako Co., Ltd.) was heated to 90°C. type), 6000 rpm
Stirred at m. The black colored initial reactant was added to the Kuraray Poval aqueous solution under stirring to obtain a black emulsion. This emulsion was cooled to 40°C, then 4.62g of dodecylbenzenesulfonic acid was added, the temperature was gradually raised, and the emulsion was heated and stirred at temperatures of 50°C, 70°C, and 90°C for 2 hours each, until the emulsified state was reached. A suspension of polycondensation-cured black resin particles was obtained. When this suspension was observed under an optical microscope (600 times magnification), it was found that it consisted of spherical fine particles with a particle diameter of approximately 5 μm. Black resin fine particles were filtered from the suspension, washed with water, dried at 100°C for 1 hour, and then
After heat treatment at 0° C. for 5 hours, the mixture was lightly crushed in a mortar to obtain a powder of black resin fine particles having a clear black color.

When 200 fine particles of the cured resin thus obtained were observed using a scanning electron microscope, they were true spherical fine particles with a particle diameter ratio (major axis/minor axis) of 1.04, and were not granulated. Since no carbon black was observed, it was found that most of the added CB was dispersed in the black resin fine particles. When the particle size of the black resin fine particles was measured using a Coulter counter, the average particle size was 5.05 μm and the particle size distribution was also very sharp. In addition, this resin fine particle has colorability, dispersibility,
When the water resistance and other properties were examined as described above, the black resin spherical fine particles were excellent in all physical properties.

The results are shown in Table 5. - Examples 8 to 10 - In Example 7, CB (1) and (3) obtained in Reference Examples 1 and 3 and untreated C were used instead of CB (2).
Black resin fine particles were obtained in the same manner as in Example 7, except that B (the above-mentioned MA-600) was used under the conditions shown in Table 3.

The results are shown in Table 5. - Examples 11 to 16 and Comparative Examples 5 and 6 - Same method as Example 7 except that in Example 7, the amount of CB added, the amount of emulsifier, the degree of methanol miscibility, and the degree of acetone miscibility were set to the conditions shown in Tables 3 and 4. Black resin fine particles were obtained.

The results are shown in Tables 5 and 6. -Example 17- Black resin fine particles were obtained in the same manner as in Example 7 except that cyclohexanecarboguanamine was used instead of benzoguanamine. The results are shown in Table 6.

Note that Examples 7 to 17 and Comparative Examples 5 and 6
The evaluation criteria for the colorability of the colored resin fine particles are as follows. Good: The color difference between the inorganic pigment alone and the colored resin fine particles is within 5%. Δ: The color difference between the inorganic pigment alone and the colored resin fine particles is more than 5% and less than 10%. ×: The color difference between the inorganic pigment alone and the colored resin fine particles is 10% or more.

Tables 3 and 4 show the synthesis conditions of Examples 7 to 17 and Comparative Examples 5 and 6.

[0047]

[Table 3]

[0048]

[Table 4]

[0049]

[Table 5]

[0050]

[Table 6]

As shown in Tables 5 and 6, the colored resin fine particles of the examples are black resin spherical fine particles with excellent colorability, dispersibility, water resistance, and heat resistance, and the CB-treated product has a higher resistance than the non-CB-treated product. It has better coloring properties. In Comparative Example 5, C
Since the B content exceeded the range of 1 to 30%, the average particle size and particle size ratio were large, and the dispersibility was low. In Comparative Example 6, the CB content was below the range of 1 to 30%, so the colorability was poor.

[0052]

[Effects of the Invention] The colored resin spherical fine particles of the present invention and the method for producing the same have the following advantages over conventional ones. ■ The colored resin spherical fine particles of this invention have excellent physical properties originally possessed by amino resins, such as heat resistance,
Excellent solvent resistance, chemical resistance, and durability.

■ The colored resin spherical fine particles of this invention are:
It has excellent compatibility with plastics such as thermoplastic resins and thermosetting resins, natural rubber, synthetic rubber, and vehicles for printing inks and paints. (2) The colored resin spherical fine particles of the present invention have excellent coloring power, are perfectly spherical, and have a narrow particle size distribution, so when mixed with a molding resin, they have good fluidity during processing and improve workability. Furthermore, by arbitrarily mixing the colored resin spherical fine particles having different colors and particle sizes, various colors with textures different from those of conventional pigments can be produced.

■ The method for producing colored resin spherical fine particles of the present invention utilizes the excellent physical properties originally possessed by amino resins,
For example, it is possible to produce colored resin spherical fine particles that are perfectly spherical, have a narrow particle size distribution, and have excellent colorability in which inorganic pigments are uniformly dispersed, without impairing heat resistance, solvent resistance, and chemical resistance. (2) The colored resin spherical fine particles of the present invention can be produced by controlling the particle size of the colored resin spherical fine particles within the range of 0.1 to 50 μm using any industrially advantageous method.

Claims (6)

[Claims] 1. Colored resin spherical fine particles in which a cured amino resin product and an inorganic pigment are integrated, and the ratio of the inorganic pigment to the total amount of the cured amino resin product and inorganic pigment is 1 to 30% by weight. 2. The cured amino resin product is a reaction product of an amino compound and formaldehyde in which at least one guanamine selected from the group consisting of benzoguanamine, cyclohexanecarboguanamine, and cyclohexenecarboguanamine accounts for 40 to 100% by weight. 2. The colored resin spherical fine particles according to claim 1, wherein the inorganic pigment is carbon black and is treated with a compound having a functional group having reactivity and/or affinity with the functional group. 3. The colored resin spherical fine particles according to claim 1 or 2, having a particle diameter ratio (major axis/minor axis) in the range of 1.0 to 1.1. 4. An amino resin and an inorganic pigment are mixed, emulsified, and polycondensed in the emulsified state, so that the ratio of the pigment to the total amount of the cured amino resin product and the inorganic pigment is 1 to 30% by weight.
A method for producing colored resin spherical fine particles by integrating a cured amino resin and an inorganic pigment so that the following is achieved. 5. The amino resin is an initial reaction product of an amino compound and formaldehyde in which at least one guanamine selected from the group consisting of benzoguanamine, cyclohexanecarboguanamine, and cyclohexenecarboguanamine accounts for 40 to 100% by weight; 5. The method for producing colored resin spherical fine particles according to claim 4, wherein the pigment is carbon black and is treated with a compound having a functional group having reactivity and/or affinity with the functional group. Claim 6: The emulsifier is 1 to 30% of the amino resin.
The method for producing colored resin spherical fine particles according to claim 4 or 5, wherein the colored resin spherical fine particles are used in a range of % by weight.