JPH0291160A - Dispersant for coloring agent for thermoplastic resin and composition containing same - Google Patents

Abstract

PURPOSE:To obtain the title dispersant which can give dispersibility to a pigment when added thereto even in a small amount and therefore is not detrimental to the inherent properties of a thermoplastic resin by adding a metal salt of a polymer based on an alpha,beta-ethylenically unsaturated carboxylic monomer. CONSTITUTION:A metal salt of a polymer (desirably, of a number-average MW<=5000 and an acid value of 140-300) based on an alpha,beta-ethylenically unsaturated monomer having at least one carboxyl group (e.g., acrylic acid) or a copolymer of this monomer with styrene or the like is used as a dispersant for a coloring agent for a thermoplastic resin. The metallic ion which constitutes the metal salt is selected from among the elements of Groups IIA, IIB and IIIA. This dispersant can exhibit an excellent dispersing effect in such a way that the adsorbability of the dispersant by the surface of a pigment is increased and the spatial blocking effect is increased, so that the pigment particles can be prevented from being agglomerated.

Description

Detailed Description of the Invention (Objective of the Invention) (Industrial Application Field) The present invention provides a dispersant (hereinafter referred to as a thermoplastic resin coloring agent) capable of imparting excellent dispersibility to a colorant for a thermoplastic resin. (referred to as a dispersant for colorants).

(Prior Art) Inorganic or organic pigments are usually used to color synthetic resins, and at that time, dispersants are also used.

If a dispersant is not used, the resin and pigment are generally mixed,
When milled, the pigment aggregates in the resin matrix. It is known that the degree of pigment aggregation is particularly high when carbon black or organic pigments are used.

Poor dispersion of pigments in resin causes a decrease in coloring power, blurring of colors, uneven coloring, etc., which not only impairs the commercial value of plastic products, but also reduces the ability to achieve the same color compared to pigments with excellent dispersibility. It is also economically disadvantageous because it is necessary to increase the amount of pigment blended in order to obtain a resin product of high quality.

Conventionally, processed pigments in which a dispersant is uniformly mixed into the pigment have been used for the purpose of improving the dispersibility of the pigment in the resin, and as described in European Patent No. 23387, A method of surface treating pigments with a dispersant such as a 12-hydroxystearic acid derivative has also been proposed.

In the above-mentioned processed pigments, compounds that have been known for a long time as dispersants include magnesium stearate, calcium stearate, barium stearate,
Metal salts of higher fatty acids such as zinc stearate, aluminum stearate, and lithium stearate are the main ingredients, and higher fatty acid amides such as methylene bis (stearic acid amide) and waxes are also used as necessary.

In order to color synthetic resins, in addition to the processed pigments mentioned above, masterbatches (processed pigments kneaded into the resin at a high concentration), colored pellets 1 to 1 (processed to give the final coloring concentration in the resin), (mixed with pigment), toner color (
Liquid colors (mixtures of processed pigments, plasticizers, and surfactants) are used. The effect on dispersibility depends primarily on the performance of the dispersant blended.

The dispersants used in processed pigments and the like described above not only have excellent pigment dispersion performance, but also do not bleed when blended with resin and do not deteriorate resin physical properties such as strength and dimensional stability. The current situation is that there is a need for excellent performance such as not impairing water resistance, heat resistance, and weather resistance, and that sufficient products have not yet been developed.

(Problems to be Solved by the Invention) In view of the problems of the prior art described above, the present inventors have conducted extensive research and found that at least one It has been found that a solid metal salt of luponic acid, which is a combination of a polymer containing an α,β-ethylenically unsaturated monomer having 5 carboxyl groups as an essential component, and a metal ion, preferably a polyvalent metal ion, is extremely effective. The present invention has now been completed.

(Structure of the Invention) (Means for Solving the Problems) To summarize the present invention, the first invention comprises at least one
A salt of a polymer containing an α,β-ethylenically unsaturated monomer having 5 carboxyl groups as an essential component and a metal ion,
For example, the heat treatment method is characterized in that it contains as an active ingredient a carboxylic acid metal salt of the carboxyl group-containing polymer and a metal ion selected from the main group, subgroup elements, and main group elements of group 3 of the periodic table. A second invention relates to a colorant dispersant for a plastic resin, and a second invention relates to a colorant composition comprising the colorant dispersant and a powdery solid colorant; The present invention relates to a thermoplastic resin composition with excellent colorability, characterized by comprising a dispersant, a colorant, and a thermoplastic resin serving as a dispersion medium.

Hereinafter, the configuration of the present invention will be explained in detail.

First, a description will be given of the carboxylic acid metal salt of a polymer whose essential component is an α,β-ethylenically unsaturated monomer having at least one carboxyl group, which is a dispersant for a colorant of a thermoplastic resin used in the present invention. do.

The carboxylic acid metal salt of the above-mentioned polymer is prepared by polymerizing an α,β-ethylenically unsaturated monomer containing at least one free carboxyl group to prepare a carboxyl group-containing polymer, and then adding the free carboxyl group. and a metal compound to form a carboxylic acid metal salt.

In the present invention, monovalent unsaturated carboxylic acid monomers such as acrylic acid and methacrylic acid are typically used as the α,β-ethylenically unsaturated monomers, but
Maleic anhydride, maleic acid half esters, fumaric acid, and the like can also be used, but are not limited to these.

A desired material can be used in consideration of its compatibility with the thermoplastic resin serving as the dispersion medium.

Examples of such comonomer components include aromatic vinyl compounds such as styrene and α-methylstyrene, and aliphatic unsaturated hydrocarbons such as diynebutylene and 2,4,4-trimethylpentene. Styrene is preferred. Furthermore, if necessary, unsaturated carboxylic acid esters such as methyl (meth)acrylate can also be used.

The molecular weight of the small polymer containing the α,β-ethylenically unsaturated monomer having at least one carboxyl group as an essential component according to the present invention is determined by number average from the viewpoint of good dispersion of the pigment in the thermoplastic resin. Those with an intermolecular number of 5000 or less are preferable, and those with an acid value of 140 to 300 are more preferable.

In addition, the number average intermolecular number is 5000 or less and the acid value is 140 to 3.
Copolymers of 00 are commercially available from S, C, JOhnSOn, such as "JOhnCrl/Bi' 67,
As 678, 680, 682, styrene/α-methylstyrene/acrylic acid type or styrene/methyl methacrylate/acrylic acid type are easily available.

A copolymer containing a low molecular weight free carboxyl group, such as the JOhnCry drawer described above, is used as a raw material for producing easily dispersible pigments in an aqueous vehicle system, for example, in U.S. Pat. 4.03
This is a known method as seen in the specification of No. 6.652.

However, the above-mentioned U.S. Patent No. 4,168,811
In the method described in the specification, an aqueous slurry of a pigment is treated with an alkaline solution of an acidic resin containing carboxyl groups, and then acidified to insolubilize the acidic resin to prepare a pigment coated with the insolubilized resin. It is. Also, US patent tube 4.
036.6s2@In the specification, a solid pigment cake is mixed with ammonia and an ammonia-soluble resin (the copolymer containing a low molecular weight free carboxyl group described above), and water is removed from the mixed system. The ammonia-soluble resin coated pigment is prepared by solidification and subsequent application of high shear stress. The manufacturing techniques for these easily dispersible pigments are unrelated to the present invention, as will be described later.

Next, a method for preparing the carboxylic acid metal salt of the above-mentioned carboxyl group-containing polymer according to the present invention will be explained.

The dispersant for thermoplastic resin colorants according to the present invention is prepared by dissolving the carboxyl group-containing polymer described above in water together with an alkali metal hydroxide such as caustic soda or caustic potash to form an aqueous solution. A free carboxyl group may be reacted with a metal compound to form a carboxylic acid metal salt. In the present invention, the metal ion component constituting the preferred carboxylic acid metal salt is one or more selected from the main group and subgroup of Group 2 of the Periodic Table, and the main group of Group 3.

As this type of metal compound, for example, water-soluble salts such as alkaline earth and earth elements, more specifically halogen compounds, sulfates, nitrates, acetates, etc. are used. The dispersant for a colorant of the present invention can be produced by adding an aqueous solution of these metal compounds to an aqueous solution of the above-mentioned carboxyl group-containing polymer to precipitate a solid carboxylic acid metal salt. In addition, in the present invention, from the viewpoint of good dispersibility of the pigment, 30% of the free carboxyl groups
The above may be reacted with the metal compound described above to form a carboxylic acid metal salt.

The thermoplastic resin colorant dispersant of the present invention prepared as described above is generally a white powdery solid, and is more suitable for both inorganic and organic pigments than known dispersants. It is extremely desirable because it exhibits excellent dispersibility and does not impair the physical properties such as heat resistance, weather resistance, and water resistance of the thermoplastic resin that is the dispersion medium.

The amount of the colorant dispersant of the present invention to be blended with the pigment varies depending on the type of pigment, but generally, for inorganic pigments, it is 5 to 20% of the pigment, and for organic pigments, it is 50 to 200% of the pigment. 4% heavy M gives favorable results.

When using the colorant dispersant of the present invention, known metal soaps such as stearic acid and 12-hydroxystearic acid may be blended depending on the purpose of use, such as controlling the melting point of the thermoplastic resin composition. There is no problem.

In such cases, during the manufacturing process of carboxylic acid metal salts,
For example, a composition that is homogeneous can be obtained by adding a low molecular weight styrene-acrylic acid copolymer and an aqueous solution of a metal compound in which a desired amount of higher fatty acids are dissolved in an alkali.

To prepare a processed pigment using the above-mentioned colorant dispersant of the present invention, add a predetermined amount of the above-described colorant dispersant to the dry pigment, and mix uniformly using a mixer such as a Henschel mixer. do it.

When the processed pigment thus obtained is used as a coloring agent in the production of a masterbatch, it exhibits superior dispersibility compared to processed pigments containing conventionally known metal soaps or other dispersants.

The coloring agent dispersed in the thermoplastic resin by the thermoplastic resin colorant dispersant of the present invention is a powdery solid, and is usually a fine solid with a primary particle size of 20 microns or less.

Colorants of this type include, for example, titanium dioxide, red color,
Yellow and black iron oxide, barium sulfate, aluminum hydroxide, calcium carbonate, talc, clay, silica, magnetic iron oxide, lead chromate, zinc chromate, strontium chromate, carbon black, aluminum, brass, iron, etc. Various inorganic pigments containing colorants, fillers, conductive materials, magnetic materials, etc.; various organic pigments such as phthalocyanine pigments, isoindolinone pigments, benzimidacilone pigments, quinacridone pigments, indanthrene pigments, dioxazine pigments ; and so on.

In the present invention, the thermoplastic resin serving as the dispersion medium includes:
Polyethylene, polypropylene, polystyrene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer resin, ethylene-vinyl acetate copolymer resin, ABS resin, As resin, polyamide resin, polyacetal resin, polycarbonate-1
What is generally called a thermoplastic resin, such as resin or PET resin, is used.

When coloring the various thermoplastic resins described above, the dispersant for coloring agents for thermoplastic resins of the present invention can impart dispersibility of 1Ω to pigments with a small amount added.

The thermoplastic resin colorant dispersant of the present invention exhibits an excellent effect on pigment dispersibility as described above, but this is because the colorant dispersant of the present invention has a plurality of polar groups in side chains. , the adsorption ability of the dispersant to the pigment surface increases compared to known stearic acid metal soaps, etc., and the steric protection effect increases, preventing aggregation of pigment particles and exhibiting an excellent dispersion effect. It is assumed that

〔Example〕

Hereinafter, the present invention will be explained in more detail using reference examples and examples, but the present invention is not limited by these examples unless the gist of the invention is exceeded.

Note that parts in the examples mean parts by weight.

[Reference example]

Preparation example of dispersant> Reference example ■Dispersant A “JOhnCryl 682” (S, C, JOhn
Manufactured by SOn; Island = 980, Hen = 16201, Acid value 246,
Softening point 110°C, glass transition point 50°C) 57.1g,
Industrial stearic acid 71.1g, caustic soda 20.0
g was added to 1000 d of water, heated to 75-80°C and stirred to obtain a transparent solution. Next, a solution prepared by dissolving 30.59 g of anhydrous calcium chloride in 500 m of water was added at once to this mixed solution while stirring strongly, and the mixture was stirred at 75 to 80° C. for 1 hour.

The generated fine precipitate was suction filtered using Nutsche, and
peptized in water from step d, refiltered, dried at 110'C, crushed,
128.69 of a white powder with a softening point of 136-137°C was obtained.

As a result of measuring the infrared absorption spectrum, 1550Cm-1
Absorption band derived from the carbonyl of carboxylade, 7
An absorption band originating from the five hydrogen atoms of the benzene ring was observed at 00 Cm-1,760 cm-1, and an absorption band originating from carbonyl carboxylate near 1720 cm' was not observed.

Reference example (2): Dispersant B "Johncryl 682" 57.1g, industrial stearic acid 71.1g, caustic soda 20.0! ? was added to 1,000 ml of water and heated to 75-80°C with stirring to obtain a clear solution. Next, a mixed solution of 55.9 g of magnesium chloride hexahydrate and 500 d of water was added at once to this mixed solution while stirring strongly, and the mixture was stirred at 65 to 70° C. for 1 hour.

The generated fine white precipitate was suction-filtered using a Nutsche filter.
Peptized in 0 (7!) water, refiltered, dried at 110'C, ground, white powder 115.0 with a softening point of 120-121°C.
I got a 9.

When we measured the infrared absorption spectrum, it was 1570cm"
Absorption band derived from carboxylade, 700 cm-'
In 760 and 1B-1, an absorption band originating from the five hydrogen atoms of the benzene ring was observed, and an absorption band originating from the carbonyl of the carboxyl group was not observed.

Reference example ■: Dispersant C "Johncryl 882" 57.1g, industrial stearic acid 71.1g, caustic soda 20.09g, water 1
A clear solution was obtained by heating and stirring at 70-75°C. Next, while stirring this mixture strongly, a mixture of 37.99 parts zinc chloride and 500 parts water was added at once, and 7 parts
Stirred at 0'C for 1 hour.

The resulting fine precipitate was suction filtered using a Nutsche filter.

This precipitation is 20007! The mixture was peptized in water, filtered again under suction, dried at 110'C, and ground to obtain 144.2 g of fine white powder. The softening point of this product was 120-121°C, and the infrared absorption spectrum chart was similar to that described above.

Reference example @) Bidispersant D “JOhnCryl 680” e5. og, industrial stearin 171.1g, caustic soda 20.09g, water 1
00 (7) and heated and stirred at 70-75°C to obtain a clear solution.

Next, while stirring this mixture strongly, MQCβ2・6H
Add a mixture of 2055.9 g and 500 d of water at once,
Stirred at 0'C for 1 hour.

The generated precipitate was filtered with suction using a Nutsche filter, peptized with 2000 d of water, filtered with suction again, dried at 110'C, and pulverized. In this way, 120.0 g of white powder was obtained. The softening point of this product was 126°C, and the infrared absorption spectrum of Char 1 was similar to that described above.

Reference Example 02 Dispersant E "Johncryl 680" 65.09, 71.1 g of industrial grade Su-r7') Am, and 20.09 g of caustic soda were added to water iooomi, and the mixture was stirred and heated to 70°C to obtain a transparent solution. Next, a mixed solution of 30.5 g of anhydrous calcium chloride and 500 ml of water was added at once to this mixed solution with strong stirring, and the mixture was stirred at 70'C for 1 hour.

The generated precipitate was filtered with suction using a Nutsche filter, peptized in 2000 d of water, filtered with suction again, dried at 110'C, and pulverized. In this way, a white powder with a softening point of 139°C
．． I got 39. The infrared absorption spectrum chart of this product was similar to that described above.

Reference example (6): Dispersant F "Johncryl 682" 57.1g, industrial stearic acid yi, ig, caustic soda 20.0g, water 1
000 ml and heated to 70°C with stirring to obtain a clear solution. Next, while stirring this mixture strongly, An(N
A mixture of 65.6 g of O3)2.9H2 and 50 (7 g) of water was rapidly added and stirred at 65-70'C for 1 hour.

The generated precipitate was filtered with suction using a Nutsche filter, peptized in 2000 g of water, filtered with suction again, dried at 110° C., and pulverized. In this way, a white powder with a softening point of 183° C. 134.
5g was obtained. When the infrared absorption spectrum was measured, in addition to an absorption band at 1580 cm' derived from the carbonyl of carboxylard, a slight absorption band at 1710 cm' derived from the carbonyl of the carboxyl group was observed. existence was presumed.

Reference example ■: Dispersant G "Johncryl 682" 57.1g, industrial hydroxystearic acid 75.1g, caustic soda 20.
0 g was added to 1000 d of water, heated to 70° C. and stirred to obtain a transparent solution.

Next, add 3 parts of zinc chloride to this mixed solution while stirring strongly.
A mixture of 7.59 and 500 d of water was added at once and stirred at 60'C for 1 hour.

The resulting fine precipitate was suction filtered using a Nutsche filter.

This precipitate was peptized in 100ml of water, filtered again under suction, dried at 110°C, and pulverized to obtain 147.7g of white powder with a softening point of 145°C. When the infrared absorption spectrum was measured, an absorption band derived from the carbonyl of carboxylade was found at 1550 Cm-1, and an absorption band at 1710 Cm-1770 Cm-
An absorption band originating from the five hydrogen atoms of the bempine ring was observed at 1, and an absorption band originating from the carbonyl of the carboxyl group at 1710 cm-' was hardly observed.

Reference example (8) Bidispersant H "Johncryl 682" 57.1 g, industrial hydroxystearic acid 75.1 g, caustic soda 20
．． 09 was added to 1000 d of water and heated to 70°C with stirring to obtain a transparent solution.

Next, add barium chloride 2 to this mixed liquid while stirring strongly.
Eiwamono 67, illusion and water 5007! Add the mixture of 6 at once.
Stirred at 0'C for 1 hour.

The fine precipitate formed was filtered with suction using a Nudzier.

This precipitate was peptized in 10007 water and filtered again with suction.
It was dried at 110'C and ground to obtain 130.2g of white powder with a softening point of 167C. When the infrared absorption spectrum was measured, an absorption band derived from the carbonyl of carboxylade was found at 1560 Cm-1, and an absorption band at 700 cm' 760 cm.
An absorption band originating from the five hydrogen atoms of the benzene ring was observed at 1, and an absorption band originating from the carbonyl of the carboxyl group at 1710 Cm-1 was hardly observed.

Reference example (9): Dispersant■ "Johncryl 682" 57.1g, industrial hydroxystearic acid 75.1g, caustic soda 20.
0g in water ioo.

d and heated and stirred at 70°C to obtain a clear solution.

Next, a mixture of 55.9 g of magnesium chloride hexahydrate and 50 (7 g) of water was added at once to this mixed solution with strong stirring, and the mixture was stirred at 60'C for 1 hour.

The fine precipitate formed was filtered with suction using a Nudzier.

This precipitate was peptized in 100 g of water, filtered again with suction, dried at 110'C, and ground to give 120.19 g of white powder with a softening point of 131°C. When the infrared absorption spectrum was measured, an absorption band derived from the carbonyl of carboxylade was found at 1560 cm', and an absorption band at 700 cm 1 760 c
An absorption band derived from the five hydrogen atoms of the benzene ring was observed at m', and an absorption band derived from the carboxyl at 1710 Cm-1 was hardly observed.

Reference example 0Φ: Dispersant J "Johncryl 682" 57.1g, industrial hydroxystearic acid 75. 1g, caustic soda 20
．． 0 g was added to 1000 d of water, heated to 70°C and stirred to obtain a clear solution.

Next, add 30% calcium chloride to this mixed solution while stirring strongly.
．． Add a mixture of 59 and 500 m of water at once, and heat to 1 at 60'C.
Stir for hours.

The resulting fine precipitate was suction filtered using a Nutsche filter.

This precipitate was peptized in 200°C (7!) water, filtered again under suction, dried at 110°C, and ground to obtain 125.8g of white powder with a softening point of 128°C. As a result of measurement, an absorption band derived from the carbonyl of carboxylade was observed at 1550 cm-1, 700 parts m-1760 parts m
An absorption band derived from the five hydrogen atoms of the benzene ring was observed at -1, and an absorption band derived from the carbonyl of the carboxyl group at 1710 Cm-1 was hardly observed.

[Example] Test example of dispersant> Example 1: Test example of dispersant ■ Titanium oxide (R-680: manufactured by Ishihara Sangyo ■) as an inorganic pigment, Penkara (110t4: manufactured by Bayer AG), as an organic pigment Using phthalocyanine blue (“Fast Dan” Blue GNP Co., Ltd.: Dainippon Ink & Chemicals (t1%j), Phthalocyanine Green (“’) 7 Stogen Pagliin S2” manufactured by Dainippon Ink & Chemicals), these pigments Add the dispersant according to the proportions shown in Tables 1 and 2,
A processed pigment was prepared by mixing well.

The dispersants shown in Table 1 were fine powders that had been sufficiently ground and passed through a 100-mesh screen.

Next, the above-mentioned processed pigment was added to 100 parts of polyethylene resin (medium-low pressure method, trade name 'Shorex' 6080: manufactured by Showa Denko K.K.), and in the case of an inorganic pigment, the pigment component in the processed pigment was 0.5. 1 part, or in the case of organic pigments, the pigment component in the processed pigment is 0.1 part, mix well, and mold the resin composition at 200'C using an in-line injection molding machine. A molded product was produced by injecting the mixture into a mold with a thickness of .5 sides.

The obtained molded product was heated to 180'0. After pressing at 100 atmospheres for 1 minute to form a thin film, the particle size of the pigment was measured using a microscope.
The dispersibility was evaluated by

The dispersibility was evaluated based on the average diameter of pigment particles within a field of 600 microns in diameter under a microscope according to the following criteria: Evaluation criteria: 5: Average particle diameter 5 μ or less 4: 5-103:
, 10-302: tt
3Q~1001: II
100 or more The smaller the average diameter of the particles, the better the dispersibility. The results are shown in Tables 1 and 2.

Table 1 (blank below) Example 2: Dispersant test example ■ Polypropylene (Chisso Polypro 1016; manufactured by Chisso Corporation), polystyrene (Dix Styrene CR-3500)
Using processed pigments prepared in the same manner as in Example 1, resin moldings were made using an injection molding machine using processed pigments prepared in the same manner as in Example 1. After making and pressing into a thin film, the pigment particles were observed under a microscope to evaluate their dispersibility. The evaluation criteria were the same as in Example 1. The pigments used were titanium oxide and phthalocyanine blue.

The results are shown in Tables 3 and 4.

(The following is a blank space) Table [Effects of the invention] α having at least one carboxyl group of the present invention,
A dispersant for a coloring agent for a thermoplastic resin, which is characterized by containing a carboxylic acid metal salt of a polymer containing β-ethylenically unsaturated heptamer as an essential component, is a dispersant for a coloring agent of various thermoplastic resins. When coloring, excellent dispersibility can be imparted with a small amount added to the pigment. Further, the colorant dispersant for a thermoplastic resin of the present invention has a property of not impairing the inherent physical properties of the thermoplastic resin as a dispersion medium, and has extremely high utility value.

Patent applicant Dainippon Ink & Chemicals Co., Ltd.
Kawamura Physical and Chemical Research Institute Representative Patent Attorney Mizu
Yoshio No

Claims (1)

[Scope of Claims] 1. A thermoplastic resin containing a carboxylic acid metal salt of a polymer whose essential component is an α,β-ethylenically unsaturated monomer having at least one carboxyl group. Dispersant for colorants. 2. α, β- where the polymer has an aromatic vinyl compound and/or aliphatic unsaturated hydrocarbon having a number average molecular weight of 5000 or less and at least one carboxyl group or acid anhydride group
The colorant dispersant according to claim 1, which is a copolymer copolymerized with an ethylenically unsaturated monomer as an essential component. 3. The colorant dispersant according to claim 1, wherein the polymer is a styrene-(meth)acrylic acid copolymer having a number average molecular weight of 5,000 or less and an acid value of 140 to 300. 4. The coloring according to claim 3, wherein the metal ion constituting the metal salt is one or more elements selected from the main group and subgroup of Group 2 of the Periodic Table, and the main group of Group 3. Dispersant for pharmaceuticals. 5. A colorant composition for a thermoplastic resin, characterized by comprising a colorant and a carboxylic acid metal salt of a polymer whose essential component is an α,β-ethylenically unsaturated monomer having at least one carboxyl group. thing. 6. α, β- where the polymer has an aromatic vinyl compound and/or aliphatic unsaturated hydrocarbon having a number average molecular weight of 5000 or less and at least one carboxyl group or acid anhydride group
The colorant composition according to claim 5, which is a copolymer formed by copolymerizing an ethylenically unsaturated monomer as an essential component. 7. The colorant composition according to claim 5, wherein the polymer is a styrene-(meth)acrylic acid copolymer having a number average molecular weight of 5,000 or less and an acid value of 140 to 300. 8. The coloring according to claim 7, wherein the metal ion constituting the metal salt is one or more elements selected from the main and subgroups of Group 2 and the main group of Group 3 of the Periodic Table. agent composition. 9. A thermoplastic characterized by comprising a carboxylic acid metal salt of a polymer whose essential component is an α,β-ethylenically unsaturated monomer having at least one carboxyl group, a coloring agent, and a thermoplastic resin. Resin composition. 10. α, β in which the polymer has an aromatic vinyl compound and/or aliphatic unsaturated hydrocarbon having a number average molecular weight of 5000 or less and at least one carboxyl group or acid anhydride group
- The thermoplastic resin composition according to claim 9, which is a copolymer obtained by copolymerizing an ethylenically unsaturated monomer as an essential component. 11. The thermoplastic resin composition according to claim 9, wherein the polymer is a styrene-(meth)acrylic acid copolymer having a number average molecular weight of 5,000 or less and an acid value of 140 to 300. 12. The heat according to claim 11, wherein the metal ion constituting the metal salt is one or more elements selected from the main group and subgroup of Group 2 of the Periodic Table, and the main group of Group 3. Plastic resin composition.