JP2015044763A - Producing method of stained polyamide fine particles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a more efficient producing method of stained polyamide fine particles having a feature that the degree of red is within a range of 20 to 50 as a value of indicator for red in ain Labcolor model set forth in International Commission on Illumination (CIE) in a method in which chloroauride tetrahydrate is reduced under the co-presence of nitrogen containing macromolecule in a solution in which polyamide fine particles are distributed in a solvent.SOLUTION: There is provided a producing method of stained polyamide fine particles having a feature that the degree of red is within a range of 20 to 50 as a value of indicator for red in ain Labcolor model set forth in International Commission on Illumination (CIE) in which chloroauride tetrahydrate is reduced in a condition where the chloroauride tetrahydrate and nitrogen containing macromolecule is present at 0.2 to 1.6 of weight ratio in a solution in which polyamide fine particles are distributed in a solvent at a concentration of 1 mass% or more.

Description

In the present invention, the weight ratio of chloroauric acid tetrahydrate to nitrogen-containing polymer is 0.2 to 1.6 in a solution in which polyamide fine particles are dispersed in a solvent at a concentration of 1% by mass or more. Chloroauric acid tetrahydrate is reduced in red, and the reddish redness is in the range of 20-50 in terms of the redness index a ^* of the International Lighting Commission (CIE) L ^* a ^* b ^* color system. The present invention relates to a method for producing colored polyamide fine particles.

Polyamide powder is commonly used as a raw material for cosmetics, for example, as a material for improving the feeling of touch such as foundation, eye shadow, eyeliner, lipstick and the like. In addition to the polyamide powder, these cosmetic compositions contain inorganic solid powders and other organic solid powders and liquid components according to their functions. It is necessary to uniformly mix and disperse the organic dye.
However, in many cases, these pigments and coloring dyes are separately mixed and dispersed, so that organic dyes and pigments are liberated, which may cause problems in product stability.

  In order to prevent these, organic compounds such as red 201, red 202, red 204, red 205, red 220, red 226, organic pigments are previously added to inorganic compounds such as zirconium compounds, barium compounds or aluminum compounds. There are rakes colored with red 3, red 4, yellow 205, yellow 401, orange 203, orange 204, blue 404, green 3 and other legal dyes. Although these rakes have many color choices, the organic pigments are highly soluble in water, causing discoloration due to the presence of water in the composition and sweat during use, and the skin is stained with pigments. There was a problem such as.

  Further, a technique for coloring these organic pigments on polyamide powder has also been clarified. For example, a method of dyeing commercially available polyamide powder in the same manner as a method of dyeing general nylon fiber or nylon woven fabric with an organic acid dye is disclosed (see Patent Document 1). According to this, it is shown that the elution property to water is lowered by fixing the pigment by dyeing, but there is still a slight color fading.

On the other hand, as a cosmetic coloring material, a technique for adhering a coloring material using local plasmon absorption of metal fine particles to a carrier such as an inorganic material or an organic material has been developed. For example, by attaching gold particles obtained by reducing chloroauric acid to the surface of a carrier such as mica or talc at the same time as its generation, it is chemically stable and has an elegant high-grade color without color variation. A cosmetic material has been obtained (see Patent Document 2).
However, the gold particles coated on the surface of the support adhere to the surface of the support in the reduced state, but there is a problem that the gold particles gradually come off in the washing process after the completion of the reaction. However, after coating gold, it was necessary to fix the gold to the support surface using a surface treatment agent.

  For this reason, a stable metal colloid solution or a dried product can be prepared by coating reduced metal fine particles with a protective polymer having a specific functional group or protecting with a high molecular weight pigment dispersion, and these can be used as a coloring material. Alternatively, a colored resin composition is obtained by kneading with a resin as a paint (see Patent Document 3 or 4).

  In order to obtain a colored polyamide powder that is less likely to be discolored by water or the like after being colored and that maintains a vivid color tone stably, it is necessary to use a coloring material that utilizes local plasmon absorption of metal fine particles rather than an organic dye. Although it is desirable, after preparing a metal colloid solution once as in Patent Document 4 and so on, using these as a coloring material or a paint, an attempt is made to color the already fixed polyamide powder. However, sufficient coloration cannot be obtained. It has been found.

  In view of such a situation, the present inventors have intensively studied, and on the surface of the polyamide fine particles, metal fine particles protected with a nitrogen-containing polymer that causes coloration due to localized plasmon absorption are stably supported. The inventors have found a colored polyamide fine particle and a production method characterized by the above (Patent Document 5).

Japanese Patent Laid-Open No. 2002-332211 JP-A-1-215865 JP 2000-281797 A Japanese Patent Laid-Open No. 11-80647 JP 2008-88296 A

According to the invention of Patent Document 5, metal fine particles protected with a nitrogen-containing polymer that generates color by localized plasmon absorption can be stably supported on the surface of polyamide fine particles.
However, when further studies were made, in order to use these colored polyamide fine particles as a part of cosmetic raw materials, the red color of the red color was developed by the International Lighting Commission in order to secure the color when applied to human skin. It was found that it was necessary to obtain dark red colored polyamide fine particles having a value of 20 to 50 in terms of the redness index a ^* of the L ^* a ^* b ^* color system of (CIE).
Furthermore, in the method disclosed in Patent Document 5, the concentration of the polyamide fine particles in the solution is about 0.5% by mass, which is disadvantageous when producing a large amount of colored polyamide fine particles at once. became.

Accordingly, an object of the present invention is to reduce the red color of red chromoic acid tetrahydrate in a solution in which polyamide fine particles are dispersed in a solvent in the presence of a nitrogen-containing polymer in the presence of a nitrogen-containing polymer. Provided means for producing colored polyamide fine particles by a more efficient method characterized by a value of 20-50 in terms of the redness index a ^* of the L ^* a ^* b ^* color system of CIE (CIE) There is to do.

  The present inventor has intensively studied to solve the above problems, and surprisingly, in the state where the weight ratio of chloroauric acid tetrahydrate to nitrogen-containing polymer is 0.2 to 1.6, The inventors have found that the problem can be solved by reducing gold acid tetrahydrate, and have reached the present invention.

That is, in the present invention, the weight ratio of chloroauric acid tetrahydrate to nitrogen-containing polymer is 0.2 to 1.6 in a solution in which polyamide fine particles are dispersed in a solvent at a concentration of 1% by mass or more. In a certain state, chloroauric acid tetrahydrate is reduced, and the reddish red color is in the range of 20-50 in terms of the redness index a ^* of the L ^* a ^* b ^* color system of the International Commission on Illumination (CIE) The present invention relates to a method for producing colored polyamide fine particles.

  The present invention also relates to a method for producing colored polyamide fine particles, wherein the average primary particle diameter of the polyamide fine particles is in the range of 0.1 to 50 μm.

  Furthermore, in the present invention, the present invention relates to a method for producing colored polyamide fine particles, wherein the average primary particle diameter of gold fine particles in the colored polyamide fine particles is in the range of 0.001 to 0.5 μm.

  The present invention also relates to a method for producing colored polyamide fine particles, wherein the content of gold fine particles in the colored polyamide fine particles is in the range of 0.01 to 20% by mass.

  The present invention also relates to a method for producing colored polyamide fine particles, wherein the nitrogen-containing polymer is polyethyleneimine.

  The present invention also relates to a method for producing colored polyamide fine particles, wherein the nitrogen-containing polymer is polyethyleneimine and the weight average molecular weight is in the range of 1,000 to 8,000.

  The present invention also relates to a method for producing colored polyamide fine particles, wherein the solvent contains at least one selected from water, methanol, ethanol, and isopropanol.

  The present invention also relates to a method for producing colored polyamide fine particles, wherein the colored polyamide fine particles have a porous structure.

A state in which the weight ratio of chloroauric acid tetrahydrate to nitrogen-containing polymer is 0.2 to 1.6 in a solution of polyamide fine particles dispersed in a solvent at a concentration of 1% by mass or more according to the present invention. According to the production method for reducing chloroauric acid tetrahydrate, colored polyamide fine particles having a stronger redness can be produced more efficiently than the conventional production method. Further, the colored polyamide fine particles of the present invention are fixed on the surface of the polyamide particles stably after the metal fine particles are supported on the surface of the polyamide particles without moisture leaching or detaching later. It can be advantageously supplied as functional particles for optical parts in electronic fields, paints, and medical use. Moreover, since it has a specific hue of 20 to 50 in terms of the redness index a ^* of the L ^* a ^* b ^* color system of the International Commission on Illumination (CIE), it can be used as various pigments.

In the present invention, the weight ratio of chloroauric acid tetrahydrate to nitrogen-containing polymer is 0.2 to 1.6 in a solution in which polyamide fine particles are dispersed in a solvent at a concentration of 1% by mass or more. Chloroauric acid tetrahydrate is reduced in red, and the reddish redness is in the range of 20-50 in terms of the redness index a ^* of the International Lighting Commission (CIE) L ^* a ^* b ^* color system. The present invention relates to a method for producing colored polyamide fine particles.

  The polyamide fine particles in the present invention are a single sphere, a substantially spherical shape, a slanted ball shape, or a dumbbell-shaped simple substance or a mixture, but 70 mass% or more, preferably 80 mass% or more, more preferably 90 mass% or more is one kind. It is desirable that the particles have a uniform particle shape. If it is lower than 70% by mass, the gold fine particles may not be uniformly supported due to variations in particle shape.

  The polyamide fine particles in the present invention have a number average particle diameter of 0.1 to 50 μm, preferably 1.0 to 25 μm. When the number average particle diameter is smaller than 0.1 μm, the secondary cohesive force is strong and the handling operation may be deteriorated. On the other hand, when it is larger than 50 μm, when it is handled as a cosmetic product, the adhesion to the skin is lowered and the feeling of roughness may be increased.

  The particle size distribution index (PDI) of the polyamide fine particles in the present invention is 1.0 to 2.0, preferably 1.0 to 1.5. When the ratio of the volume average particle size to the number average particle size (particle size distribution index PDI) is larger than 2.0, the particle size distribution becomes wide. A uniform particle size is preferable when it is applied to a functional material or an electronic material because physical and chemical properties more than expected may be expressed.

  In addition to the non-porous structure, particles having a porous structure can also be applied to the polyamide fine particles in the present invention. In particular, a porous polyamide fine particle having a porous structure is preferable because it has a larger specific surface area than non-porous polyamide particles having the same particle diameter, and can support a large number of fine gold particles.

The BET specific surface area of the polyamide fine particles in the present invention is 0.1 to 80 m ² / g, preferably 0.5 to 50 m ² / g, and more preferably 1 to 40 m ² / g. If the specific surface area is lower than 0.1 m ² / g, the gold fine particles cannot be supported sufficiently. The larger the specific surface area, the more gold fine particles can be supported.

  When the polyamide fine particles in the present invention are polyamide porous fine particles, the average pore diameter is 0.005 to 0.5 μm, preferably 0.01 to 0.3 μm. When the average pore diameter is smaller than 0.005 μm, the gold fine particles cannot be sufficiently supported in the pores. Moreover, when larger than 0.5 micrometer, the mechanical strength of powder may become weak.

  When the polyamide fine particles in the present invention are polyamide porous fine particles, the porosity is preferably 30% to 70%. If the porosity is lower than 30%, the gold fine particles cannot be supported sufficiently inside. On the other hand, if it exceeds 70%, the uniform shape of the polyamide porous fine particles cannot be maintained, and the handling may be worsened.

  Examples of the polyamide used in the present invention include various known ones. For example, polyamide obtained by ring-opening polymerization of cyclic amide or polycondensation of dicarboxylic acid and diamine is preferably used. Specifically, the weight of amino acids such as crystalline polyamide obtained by ring-opening polymerization of cyclic amides such as ε-caprolactam and ω-laurolactam, ε-aminocaproic acid, ω-aminododecanoic acid, and ω-aminoundecanoic acid. Condensation or dicarboxylic acids and derivatives such as succinic acid, adipic acid, sebacic acid, terephthalic acid, isophthalic acid, 1,4-cyclohexyldicarboxylic acid and ethylenediamine, hexamethylenediamine, 1,4-cyclohexyldiamine, m-xylylenediamine, Examples thereof include those obtained by polycondensation of diamines such as pentamethylenediamine and decamethylenediamine. Specific examples of such polyamides include polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 66 / 6T (T represents a terephthalic acid component), and the like. Moreover, the mixture of the said polyamide may be sufficient. Among them, particularly preferred are aliphatic polyimides, and polyamide 6, polyamide 66, polyamide 12, and copolymers thereof are preferred.

  The polyamide particles used in the present invention can be used without any problem as long as they are particles made using the above polyamide. Examples of commercially available particles include SP-500 from Toray Industries, Inc., HK-5000 from Shinto Fine Co., Ltd., Ganz Pearl from Ganz Kasei Co., Ltd., and Arkema INC. ORGASOL and the like. Examples of the polyamide porous fine particles include polyamide porous fine particles described in JP-A-2005-120203.

In the colored polyamide fine particles in the present invention, the reddish red color is a value of L ^* a ^* b ^* color system redness index a ^* of the International Illumination Commission (CIE), preferably 20 to 50, more preferably 24. A range of ˜50 is desirable. When the value of the redness index a ^* is 20 or less, it may be very difficult to ensure color development when applied to human skin when the colored polyamide fine particles are used as some cosmetic raw materials.

  The colored polyamide fine particles in the present invention are produced by reducing chloroauric acid tetrahydrate in a solution in which polyamide fine particles are dispersed in a solvent in the presence of a nitrogen-containing polymer. In the present invention, it may be described as a solution, suspension, dispersion or the like in which polyamide is dispersed, but any description means a state in which polyamide fine particles are dispersed in a solvent. According to this method, since the gold fine particles generated by reduction are supported on the polyamide fine particles in a state of being coated with the nitrogen-containing polymer, the gold-containing fine particles are made of polyamide because the nitrogen-containing polymer is strongly bonded on the surface of the polyamide particles. It is considered that the particles are strongly supported in the particles and are not easily detached. On the other hand, in the method in which the polyamide fine particles are brought into contact with the reduced metal fine particle solution, the gold fine particles are hardly supported on the polyamide fine particles.

  As the solvent in the present invention, a water-soluble solvent, particularly water or alcohol, is preferably used from the viewpoint that the dispersibility of the polyamide fine particles is good and uniform gold fine particles can be supported. Examples of the alcohol in the present invention are not particularly limited thereto, but examples thereof include methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, butyl alcohol, amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, ethylene glycol, C1-C8 alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, glycerin, preferably methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, butyl alcohol, ethylene glycol, ethylene glycol monomethyl ether, C1-C4 alcohols, such as ethylene glycol monoethyl ether, are used. Preferably, methyl alcohol, ethyl alcohol, or isopropyl alcohol is used. These alcohols may be used alone, or two or more of the above alcohols may be used. A mixture of these alcohols and water is most preferably used.

  In the present invention, the concentration of the polyamide fine particles in the solution in which the polyamide fine particles are dispersed in the solvent is preferably 1 to 25% by mass. When the concentration of the polyamide fine particles is lower than 1%, the number of colored polyamide fine particles that can be produced with a constant solvent volume is reduced, which is disadvantageous in terms of efficiency. On the other hand, when the concentration of the polyamide fine particles is higher than 25%, the viscosity of the solution is improved, the stirring state becomes non-uniform, and the particle size of the gold fine particles generated as a result of the reduction varies. Work may be difficult.

Although the nitrogen-containing polymer in the present invention is not particularly limited, those having —NH ₂ or —NH— in the molecular structure are particularly desirable. This is because of the high affinity with the carboxylic acid (—COOH) or carbonyl group (> C═O) at the end of the polyamide present on the surface of the polyamide particles, so that some of the carboxylic acid (—COOH) and nitrogen-containing polymer — It is considered that an amide bond is formed between NH _{2 and} —NH—. As a result, the nitrogen-containing polymer coated with the gold fine particles is strongly bonded on the surface of the polyamide particles, so that the gold fine particles are strongly supported in the polyamide particles and are not easily detached.

  Examples of the nitrogen-containing polymer in the present invention include, but are not limited to, polyethyleneimine, polyallylamine, polyvinyl pyridine, polyvinyl pyridine, polyaniline and derivatives thereof, polypyrrole, and derivatives thereof. Of these, polyethyleneimine is preferably used.

  The weight average molecular weight of the nitrogen-containing polymer in the present invention is preferably in the range of Mw = 1,000 to 8,000. When the molecular weight is small, the function as a protective agent is weakened, so that the gold fine particles grow to increase the particle size, and the color of the colored particles may become blue. On the other hand, when the molecular weight is large, the adsorption of the nitrogen-containing polymer to the polyamide particles decreases, and the amount of gold fine particles supported decreases, so that efficient support may not be possible.

And chloroauric acid tetrahydrate in the present invention means that the trivalent hydrate of gold chloride complex (tetrachloroauric (III) acid _{tetrahydrate, HAuCl 4 · 4H 2 O)} . Even if the hydrauric acid hydration number used in the experiment is different, there is no problem as long as the weight converted to the tetrahydrate is within the specified range.

  In the present invention, the weight ratio of chloroauric acid tetrahydrate to nitrogen-containing polymer is preferably 0.2 to 1.6, more preferably 0.4 to 1.2. When the weight ratio is less than 0.2, the amount of the protective agent for gold is large, and the particles cannot grow sufficiently to cause localized plasmon absorption, and the particles may not be sufficiently colored. On the other hand, when the amount of chloroauric acid tetrahydrate is large, the amount of the fine gold particles produced due to the insufficient amount of the nitrogen-containing polymer as the protective agent increases, and the bluishness of the particles may increase.

  As a process for producing colored polyamide fine particles, a solution in which polyamide fine particles are dispersed, a nitrogen-containing polymer, and chloroauric acid tetrahydrate can be mixed if they can be mixed uniformly before reducing chloroauric acid. The degree does not affect their order of addition.

  In the present invention, the produced colored polyamide fine particles can be solid-liquid separated by a method such as decantation, filtration or centrifugation. Moreover, it can be dried by appropriately using a known powder drying method such as vacuum drying or constant temperature drying.

  The gold fine particles in the colored polyamide fine particles produced in the present invention have a primary particle diameter in the range of 0.001 to 0.5 μm, and the shape thereof is particularly limited such as spherical, indefinite shape, lump shape, needle shape, rod shape and the like. However, in order to obtain a pure color tone, it is preferable that the primary particle diameter and shape of the particles are uniform. Gold fine particles smaller than 0.001 μm are not colored because they do not exhibit metallic properties and do not exhibit localized plasmon absorption. Fine particles larger than 0.5 μm are not colored because they do not exhibit fine particle properties and do not cause localized plasmon absorption. In addition, since there is no particle size difference from the polyamide fine particles, it is difficult to support the polyamide fine particles.

  The content of the gold fine particles in the colored polyamide fine particles produced in the present invention is preferably in the range of 0.001 to 20% by mass. Furthermore, 0.01-10 mass% is preferable. If it is 0.001% or less, the gold fine particles are not sufficiently colored by plasmon resonance. If it is 20% or more, it is difficult to suppress the aggregation of gold fine particles.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. The average particle diameter, specific surface area, chromaticity and the like described below were measured as follows.

(Average particle size) The average particle size and particle size distribution of the polyamide fine particles were measured as an average value of 100 fine particles using an electron microscope (scanning electron microscope SEM and transmission electron microscope TEM). The number average particle size, volume average particle size, and particle size distribution index (PDI) are expressed by the following equations.
Number average particle size:

体積平均粒子径:

Volume average particle size:

粒子径分布指数：

Particle size distribution index:

ここで、Ｘｉ；個々の粒子径、ｎは測定数である。

Here, Xi: individual particle diameter, n is the number of measurements.

(Specific surface area) The specific surface area of the polyamide fine particles was calculated by performing three-point measurement by the BET method based on nitrogen adsorption according to ISO9277.

(Chromaticity) L ^* a ^* b ^* of the International Illumination Commission for Colored Polyamide Fine Particles (CIE) The chromaticity of the color system is measured automatically by the Color Techno System Co., Ltd. This was done using a color robot.

(Production Example 1)
A nylon solution (A) composed of 200 g of polyamide 6 (molecular weight 8000) and 800 g of phenol was prepared. To this polyamide 6 solution, 6400 g of isopropanol which is a non-solvent (B) of polyamide and 750 g of water (C) were stirred and mixed with a magnetic stirrer and stirred for 1 minute, and the solution became uniform. Polymer was precipitated after 2 minutes of stirring. The mixed solution was allowed to stand for 24 hours to complete the precipitation of the polymer. The obtained precipitated polymer was washed with warm methanol and acetone, and then the polymer was isolated by centrifugation.
When the obtained particles were observed with a scanning electron microscope, they were porous spherical particles having a number average particle size of 7.9 μm and a volume average particle size of 9.8 μm. The PDI was 1.24. The specific surface area was 28.8 m ² / g.

(Example 1)
1.25 g of polyamide porous fine particles produced by the method of Production Example 1 were dispersed in 119 g of ethanol, and 4.00 g of a 1% by weight aqueous solution of chloroauric acid tetrahydrate, polyethyleneimine (weight average molecular weight 1, 800) 20.03 g of a 1% by weight aqueous solution was added and mixed in ethanol. When this solution was heated at 70 ° C. for 1 hour, it became a suspension in which red polyamide particles were dispersed in ethanol. After filtration and solid-liquid separation, vacuum drying was performed to obtain 1.15 g of polyamide fine particles colored pink. At this time, the redness of the red color was 21.42 as the value of the redness index a ^* of the L ^* a ^* b ^* color system of the International Commission on Illumination (CIE).

(Example 2)
1.26 g of polyamide porous fine particles produced by the method of Production Example 1 were dispersed in 119 g of ethanol, and 4.00 g of a 1% by mass aqueous solution of chloroauric acid tetrahydrate, polyethyleneimine (weight average molecular weight 1, 800) 10.00 g of a 1% by weight aqueous solution was added and mixed in ethanol. When this solution was heated at 70 ° C. for 1 hour, it became a suspension in which red polyamide particles were dispersed in ethanol. After filtration and solid-liquid separation, 1.17 g of polyamide fine particles colored pink were obtained by vacuum drying. At this time, the redness of the red color was 24.05 in terms of the redness index a ^* of the L ^* a ^* b ^* color system of the International Commission on Illumination (CIE).

(Comparative Example 1)
1.26 g of polyamide porous fine particles produced by the method of Production Example 1 were dispersed in 119 g of ethanol, and 4.01 g of a 1% by weight aqueous solution of chloroauric acid tetrahydrate, polyethyleneimine (weight average molecular weight 1, 800) 0.99 g of a 1% by weight aqueous solution was added and mixed in ethanol. When this solution was heated at 70 ° C. for 1 hour, it became a suspension in which red polyamide particles were dispersed in ethanol. After filtration and solid-liquid separation, 1.14 g of polyamide fine particles colored pink were obtained by vacuum drying. At this time, the value of the redness index a ^* of the L ^* a ^* b ^* color system of the International Commission on Illumination (CIE) was 2.97.

Example 3
1.25 g of polyamide porous fine particles produced by the method of Production Example 1 were dispersed in 119 g of isopropanol, and 4.00 g of a 1% by mass aqueous solution of chloroauric acid tetrahydrate, polyethyleneimine (weight average molecular weight 1, 800) 10.02 g of a 1% by weight aqueous solution was added and mixed in isopropanol. When this solution was heated at 70 ° C. for 1 hour, it became a suspension in which red polyamide particles were dispersed in isopropanol. After filtration and solid-liquid separation, 1.21 g of polyamide fine particles colored pink were obtained by vacuum drying. At this time, the redness of the red color was 28.27 in terms of the redness index a ^* of the L ^* a ^* b ^* color system of the International Commission on Illumination (CIE).

(Comparative Example 2)
1.25 g of polyamide porous fine particles produced by the method of Production Example 1 were dispersed in 119 g of isopropanol, and 4.02 g of a 1% by weight aqueous solution of chloroauric acid tetrahydrate, polyethyleneimine (weight average molecular weight 1, 800) 1.02 g of a 1 wt% aqueous solution was added and mixed in isopropanol. When this solution was heated at 70 ° C. for 1 hour, it became a suspension in which red polyamide particles were dispersed in isopropanol. After filtration and solid-liquid separation, vacuum drying was performed to obtain 1.15 g of polyamide fine particles colored pink. At this time, the redness of the red color was 4.57 as the value of the redness index a ^* in the L ^* a ^* b ^* color system of the International Commission on Illumination (CIE).

Example 4
1.25 g of polyamide porous fine particles produced by the method of Production Example 1 were dispersed in 119 g of water, and 4.00 g of a 1% by weight aqueous solution of chloroauric acid tetrahydrate, polyethyleneimine (weight average molecular weight 1, 800) 10.00 g of a 1% by weight aqueous solution was added and mixed in water. When this solution was heated at 70 ° C. for 1 hour, it became a suspension in which red polyamide particles were dispersed in water. After filtration and solid-liquid separation, vacuum drying was performed to obtain 1.15 g of polyamide fine particles colored pink. The value of the redness index a ^* of the L ^* a ^* b ^* color system of the International Commission on Illumination (CIE) was 24.96.

(Example 5)
1.25 g of polyamide porous fine particles produced by the method of Production Example 1 were dispersed in 119 g of water, and 4.01 g of a 1% by weight aqueous solution of chloroauric acid tetrahydrate, polyethyleneimine (weight average molecular weight 1, 800) 2.52 g of a 1% by weight aqueous solution was added and mixed in water. When this solution was heated at 70 ° C. for 1 hour, it became a suspension in which red polyamide particles were dispersed in water. After filtration and solid-liquid separation, 1.19 g of polyamide fine particles colored pink were obtained by vacuum drying. At this time, the redness of the red color was 20.05 in terms of the redness index a ^* of the L ^* a ^* b ^* color system of the International Commission on Illumination (CIE).

(Comparative Example 3)
1.26 g of polyamide porous fine particles produced by the method of Production Example 1 were dispersed in 119 g of water, and 4.03 g of a 1% by weight aqueous solution of chloroauric acid tetrahydrate, polyethyleneimine (weight average molecular weight 1, 800) 1.03 g of a 1% by weight aqueous solution was added and mixed in water. When this solution was heated at 70 ° C. for 1 hour, it became a suspension in which red polyamide particles were dispersed in water. After filtration and solid-liquid separation, 1.23 g of polyamide particles colored pink were obtained by vacuum drying. At this time, the redness of the red color was 19.01 in terms of the redness index a ^* of the L ^* a ^* b ^* color system of the International Commission on Illumination (CIE).

(Example 6)
1.26 g of polyamide porous fine particles produced by the method of Production Example 1 were dispersed in 119 g of methanol, and 3.99 g of a 1% by mass aqueous solution of chloroauric acid tetrahydrate, polyethyleneimine (weight average molecular weight 1, 800) 10.05 g of a 1% by weight aqueous solution was added and mixed in methanol. When this solution was heated at 70 ° C. for 1 hour, it became a suspension in which red polyamide particles were dispersed in methanol. After filtration and solid-liquid separation, vacuum drying was performed to obtain 1.18 g of polyamide fine particles colored pink. At this time, the redness of the red color was 26.71 in terms of the redness index a ^* of the L ^* a ^* b ^* color system of the International Commission on Illumination (CIE).

(Example 7)
1.26 g of polyamide porous fine particles produced by the method of Production Example 1 were dispersed in 119 g of methanol, and 4.01 g of a 1% by weight aqueous solution of chloroauric acid tetrahydrate, polyethyleneimine (weight average molecular weight 1, 800) 5.03 g of a 1% by weight aqueous solution was added and mixed in methanol. When this solution was heated at 70 ° C. for 1 hour, it became a suspension in which red polyamide particles were dispersed in methanol. After filtration and solid-liquid separation, 1.19 g of polyamide fine particles colored pink were obtained by vacuum drying. At this time, the value of the redness index a ^* of the L ^* a ^* b ^* color system of the International Commission on Illumination (CIE) was 34.07.

(Comparative Example 4)
1.25 g of polyamide porous fine particles produced by the method of Production Example 1 were dispersed in 119 g of methanol, and 3.99 g of a 1% by mass aqueous solution of chloroauric acid tetrahydrate, polyethyleneimine (weight average molecular weight 1, 800) 0.99 g of a 1% by weight aqueous solution was added and mixed in methanol. When this solution was heated at 70 ° C. for 1 hour, it became a suspension in which red polyamide particles were dispersed in methanol. After filtration and solid-liquid separation, 1.21 g of polyamide fine particles colored pink were obtained by vacuum drying. The value of the redness index a ^* of the L ^* a ^* b ^* color system of the International Commission on Illumination (CIE) was 6.56.

  Table 1 summarizes the results of Examples 1 to 7 and Comparative Examples 1 to 4.

From the obtained results, when the weight ratio of chloroauric acid tetrahydrate to nitrogen-containing polymer is 0.2 to 1.6, the International Lighting Commission can be used regardless of which solvent is used. It was confirmed that dark red polyamide particles having a value of the redness index a ^* of L ^* a ^* b ^* color system of (CIE) in the range of 20 to 50 can be obtained.

Claims (8)

Chloroauric acid in a state where the weight ratio of chloroauric acid tetrahydrate to nitrogen-containing polymer is 0.2 to 1.6 in a solution in which polyamide fine particles are dispersed in a solvent at a concentration of 1% by mass or more. Reducing tetrahydrate,
A method for producing colored polyamide fine particles, wherein the red coloration is in the range of 20 to 50 in terms of the redness index a ^* of the L ^* a ^* b ^* color system of the International Commission on Illumination (CIE). 2. The method for producing colored polyamide fine particles according to claim 1, wherein an average primary particle size (number average particle size) of the polyamide fine particles is in a range of 0.1 to 50 μm. The method for producing colored polyamide fine particles according to claim 1 or 2, wherein an average primary particle size (number average particle size) of gold fine particles in the colored polyamide fine particles is in the range of 0.001 to 0.5 µm. The method for producing colored polyamide fine particles according to any one of claims 1 to 3, wherein the content of the gold fine particles in the colored polyamide fine particles is in the range of 0.01 to 20% by mass. The method for producing colored polyamide fine particles according to any one of claims 1 to 4, wherein the nitrogen-containing polymer is polyethyleneimine. The method for producing colored polyamide fine particles according to any one of claims 1 to 5, wherein the nitrogen-containing polymer is polyethyleneimine, and the weight average molecular weight thereof is in the range of 1,000 to 8,000. The method for producing colored polyamide fine particles according to any one of claims 1 to 6, wherein the solvent contains at least one selected from water, methanol, ethanol, and isopropanol. The method for producing colored polyamide fine particles according to any one of claims 1 to 7, wherein the colored polyamide fine particles have a porous structure.