JP5469806B2 - Thermoplastic resin composition and molded article - Google Patents

Description

  The present invention relates to a thermoplastic resin composition and a molded product used for various industrial products, sports / leisure products and the like.

  In general, aliphatic polyamides typified by nylon 6 and nylon 66 have characteristics such as excellent mechanical strength, chemical resistance, and wear resistance. Therefore, industrial products such as automobiles, electrical / electronic / mechanical parts, It is used for many purposes such as sports and leisure goods. However, aliphatic polyamides have the disadvantage that they are inferior in impact resistance, easily absorb water due to their chemical structure, have large dimensional changes in environments where the moisture content is excessively high, and further reduce rigidity. There was a practical problem. Therefore, much research has been done in the past to improve these drawbacks.

For example, a method of mixing a polyamide and an ABS resin (see Patent Document 1), a carboxylic acid group-containing copolymer obtained by blending a polyamide and an ABS resin and copolymerizing an unsaturated carboxylic acid with styrene or acrylonitrile. As a compatibilizing agent (see Patent Document 2), a method using a carboxylic acid group-containing copolymer having a limited reduced viscosity as a compatibilizing agent (see Patent Document 3), and the like. Yes.
Japanese Patent Publication No. 38-23476 Japanese Patent Publication No. 7-84549 JP 2000-17170 A

With the techniques described in these patent documents, the impact resistance is improved to some extent. However, in recent years, the size and thickness of home appliances and automobile parts have been further increased, and an improvement in the molding cycle is required. Therefore, the resin is required to have an excellent balance between impact resistance and fluidity at the time of molding, but the technique described in the above patent document is insufficient.
In addition, when an ABS resin or an ABS graft copolymer is blended, there is a problem that chemical resistance and abrasion resistance, which are advantages of polyamide, are lowered.

  Therefore, an object of the present invention is to provide a thermoplastic resin composition having an excellent balance between the impact resistance of the obtained molded article and the fluidity during molding, and also having excellent chemical resistance and wear resistance. . Another object of the present invention is to provide a molded product having excellent chemical resistance, wear resistance and impact resistance.

The present invention includes the following aspects.
[1] 70 to 90 parts by mass of polyamide (A);
An aromatic vinyl monomer and a vinyl cyanide monomer are added to a rubber-like polymer including an acid-modified α-olefin copolymer having a viscosity average molecular weight of 1000 to 9000 and an ethylene-propylene-nonconjugated diene copolymer. 8-25 parts by mass of a graft copolymer (B) obtained by polymerization,
Carboxylic acid group-containing copolymer (C) having a number average molecular weight of 20,000 to 70,000 obtained by copolymerizing an unsaturated carboxylic acid monomer, an aromatic vinyl monomer and a vinyl cyanide monomer 2 to 5 mass (However, the sum of the above (A), (B) and (C) is 100 parts by mass).
[2] The carboxylic acid group-containing copolymer (C) is a polymer latex obtained by emulsion copolymerization of an unsaturated carboxylic acid monomer, an aromatic vinyl monomer, and a vinyl cyanide monomer. The thermoplastic resin composition according to [1], which is a polymer obtained by coagulation by adding calcium acetate .
[3] A molded product, wherein the thermoplastic resin composition according to [1] or [2] is molded.

The thermoplastic resin composition of the present invention is excellent in the balance between the impact resistance of the obtained molded product and the fluidity during molding, and is excellent in chemical resistance and wear resistance.
The molded article of the present invention is excellent in chemical resistance, wear resistance and impact resistance.

<Thermoplastic resin composition>
The thermoplastic resin composition of the present invention contains a polyamide (A), a graft copolymer (B), and a carboxylic acid group-containing copolymer (C) as essential components, and another polymer (D). As an optional component.

[Polyamide (A)]
Examples of the polyamide (A) include polyamides obtained from diamines and dicarboxylic acids. Here, as the diamine, for example, ethylenediamine, diaminobutane, hexamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4- and 2,4,4-trimethylhexamethylenediamine, 1,3- and 1 , 4-bis (aminomethyl) cyclohexane, bis (p-aminocyclohexyl) methane, metaxylylenediamine, paraxylylenediamine, and the like, aliphatic, alicyclic, and aromatic diamines. Examples of the dicarboxylic acid include aliphatic, alicyclic, and aromatic dicarboxylic acids such as adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, and isophthalic acid.
Examples of polyamides include polyamides obtained by ring-opening polymerization of lactams such as ξ-caprolactam and ω-dodecalactam, polyamides obtained from 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and the like. In addition, a polyamide elastomer having a copolymerized polyamide, a mixed polyamide, a polyamide as a hard segment, and a polyether as a soft segment can be used.

  Among these, since it is industrially inexpensive and manufactured in large quantities, polycaproamide (nylon 6), polydodecamide (nylon 12), polytetramethylene adipamide (nylon 46), polyhexamethylene adipa Amide (nylon 66), polyhexamethylene sebacamide (nylon 610), and copolymers thereof, such as nylon 6/66 ("/" sign means copolymer), nylon 6 / 610, nylon 6/12, nylon 66/12, nylon 6/66/610/12, and mixtures thereof are preferable. Bis (p-aminocyclohexyl) methane / terephthalic acid / isophthalic acid polyamides are also preferred.

The number average molecular weight of the polyamide is not particularly limited, but is preferably 10,000 to 40,000.
The molecular structure of the polyamide may be any of linear polyamide, branched polyamide, and the like.
As the polymerization method of polyamide, melt polymerization, interfacial polymerization, solution polymerization, bulk polymerization, solid phase polymerization and a method combining these methods are applied, and among these, melt polymerization is preferable. When the polyamide raw material is a lactam, a polymer can be obtained by anionic polymerization.

  The content of the polyamide (A) is 5 to 95 parts by mass, preferably 15 to 90 parts by mass when the total of (A), (B), (C) and (D) is 100 parts by mass. is there. When the polyamide (A) is 5 parts by mass or more, chemical resistance and wear resistance of the obtained molded product are improved, and when the polyamide (A) is 95 parts by mass or less, the resulting molded product has resistance to resistance. In addition to improving impact properties, dimensional stability is also improved.

[Graft Copolymer (B)]
The graft copolymer (B) is obtained by adding an aromatic vinyl monomer and a vinyl cyanide monomer to a rubbery polymer containing an acid-modified α-olefin copolymer and an ethylene-propylene-nonconjugated diene copolymer. The body is polymerized.

As the ethylene-propylene-nonconjugated diene copolymer contained in the rubber-like polymer, 1,4-hexadiene, 5-ethylidene-2-norbornene, 5-vinylnorbornene, dicyclopentadiene, etc. are used as the nonconjugated diene component. The inclusion is preferred.
The ethylene-propylene-nonconjugated diene copolymer is preferably crosslinked. If the ethylene-propylene-nonconjugated diene copolymer is crosslinked, the impact resistance and chemical resistance of the resulting molded article are further improved.

Examples of the acid-modified α-olefin copolymer include an acid-modified α-olefin copolymer obtained by graft-polymerizing an unsaturated carboxylic acid to a polyolefin such as polyethylene.
Here, examples of the α-olefin include ethylene and propylene, and examples of the unsaturated carboxylic acid include acrylic acid, maleic acid, itaconic acid, maleic anhydride, itaconic anhydride, and maleic acid monoamide.
The α-olefin unit in the acid-modified α-olefin copolymer is preferably 99.8 to 60% by mass, and the unsaturated carboxylic unit is preferably 0.2 to 40% by mass. If unsaturated carboxylic acid unit is 0.2 mass% or more, the polymerization stability at the time of obtaining a graft copolymer (B) will improve. However, when it exceeds 40% by mass, the rigidity and heat resistance of the resulting resin composition tend to decrease.

The viscosity average molecular weight of the acid-modified α-olefin copolymer is 1000 to 9000, and preferably 1500 to 4000. When the viscosity average molecular weight of the acid-modified α-olefin copolymer is 1000 or more, the resulting thermoplastic resin composition has good wear resistance. Moreover, dispersibility and compatibility are excellent when it is 9000 or less.
Here, the viscosity average molecular weight is measured according to JIS K 7367-3 (1999), the solvent is decahydronaphthalene, and the temperature is 135 ° C.

In the rubbery polymer, the content of the acid-modified α-olefin copolymer is preferably 1 to 40 parts by mass with respect to 100 parts by mass of the ethylene-propylene-nonconjugated diene copolymer. When the content of the acid-modified α-olefin copolymer is 1 part by mass or more, the impact resistance of the finally obtained thermoplastic resin composition can be further improved. However, even if the compounding amount of the acid-modified α-olefin copolymer exceeds 40 parts by mass, the impact resistance is not further improved, and conversely, the rigidity and heat resistance may be lowered.
In addition, if 1 to 40 parts by mass of an acid-modified α-olefin copolymer is contained with respect to 100 parts by mass of the ethylene-propylene-nonconjugated diene copolymer, the graft for obtaining the graft copolymer (B) is obtained. Polymerization can also be stabilized.

Examples of the aromatic vinyl monomer to be graft-polymerized on the rubber-like polymer include, for example, styrene, α-methylstyrene, o-, m- or p-methylstyrene, vinylxylene, monochlorostyrene, dichlorostyrene, monobromostyrene. , Dibromostyrene, fluorostyrene, p-tert-butylstyrene, ethylstyrene, vinylnaphthalene and the like, preferably styrene and α-methylstyrene. Aromatic vinyl monomers may be used alone or in combination of two or more.
Examples of the vinyl cyanide monomer include acrylonitrile and methacrylonitrile. A vinyl cyanide monomer may be used individually by 1 type, and may use 2 or more types together.

In the rubbery polymer, in addition to the above aromatic vinyl monomer and vinyl cyanide monomer, other vinyl monomers copolymerizable therewith do not impair the purpose of the present invention. Graft polymerization may be used.
Other vinyl monomers include α, β-unsaturated carboxylic acids such as acrylic acid and methacrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, Α, β-unsaturated carboxylic acid esters such as 2-ethyl (meth) acrylate and 2-ethylhexyl methacrylate; α, β-unsaturated dicarboxylic acid anhydrides such as maleic anhydride and itaconic anhydride; maleimide, N- Examples include imide compounds of α, β-unsaturated dicarboxylic acids such as methylmaleimide, N-ethylmaleimide, N-phenylmaleimide, and N-o-chlorophenylmaleimide. Another vinyl-type monomer may be used individually by 1 type, and may use 2 or more types together.

The graft copolymer (B) is produced by a known method such as a bulk polymerization method, a solution polymerization method, a bulk suspension polymerization method, a suspension polymerization method, or an emulsion polymerization method, and emulsion polymerization can be easily performed. preferable.
Below, an example which manufactures a graft copolymer (B) by emulsion polymerization is shown.

(I) First, a predetermined amount of an ethylene-propylene-nonconjugated diene copolymer and an acid-modified α-olefin copolymer are dissolved in a solvent, and an emulsifier is added thereto to emulsify, thereby a rubbery polymer-containing liquid. To prepare.
As the solvent, aliphatic or alicyclic hydrocarbon solvents such as n-hexane and cyclohexane can be used. As the emulsifier, for example, an anionic surfactant such as potassium oleate or disproportionated potassium rosinate is used. The addition amount of the emulsifier is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the ethylene-propylene-nonconjugated diene copolymer.
As an emulsifier, for example, oleic acid is mixed with an ethylene-propylene-nonconjugated diene copolymer and an acid-modified α-olefin copolymer solution, and then an aqueous potassium hydroxide solution is added to add potassium oleate. It can also be added by forming.

(Ii) After adding water to the rubber-like polymer-containing liquid, this is sufficiently stirred and the solvent is distilled off to obtain a latex having an average particle size of 0.2 to 1 μm.

(Iii) Next, 0.1 to 5.0 parts by mass of a polyfunctional compound such as divinylbenzene and di-t-butyl are added to 100 parts by mass of the ethylene-propylene-nonconjugated diene copolymer in the latex. -Add 0.1 to 5.0 parts by mass of organic peroxide such as oxytrimethylcyclohexane, and react at 60 to 140 ° C for about 0.5 to 5.0 hours. In this way, a latex of the crosslinked ethylene-propylene-nonconjugated diene copolymer (B1) is prepared.

Since this ethylene-propylene-nonconjugated diene copolymer crosslinked product (B1) has a better physical property balance of the thermoplastic resin composition, the gel content is 30 to 90% by weight, and the average particle size is 0.00. It is preferable that it is 2-1 micrometer. When the gel content of (B1) is 30% by weight or more, the impact resistance of the finally obtained thermoplastic resin composition is further improved and the surface appearance is improved. However, when the gel content of (B1) exceeds 90% by weight, the impact resistance of the resulting thermoplastic resin composition tends to decrease. Moreover, if the average particle diameter of (B1) is 0.2 μm or more, the impact resistance of the obtained molded product is further improved, and if it is 1 μm or less, the surface appearance of the obtained molded product is improved.
Here, the gel content of the latex of the ethylene-propylene-nonconjugated diene copolymer crosslinked product (B1) is measured by the following method.
First, after the latex of the ethylene-propylene-nonconjugated diene copolymer crosslinked product (B1) is washed with dilute sulfuric acid and dried, 1 g of this is sampled and immersed in 200 ml of toluene at 115 ° C. for 5 hours. Next, after filtration through a 200 mesh stainless steel wire mesh, the obtained residue is dried. After drying, the residue is weighed and the gel content is determined by the following formula.
Gel content (%) = [residue mass after drying / mass of sample before toluene immersion] × 100 (%)

(Iv) Subsequently, 55-80 mass% of aromatic vinyl monomers and 45-20 mass% of vinyl cyanide monomers are added to the latex of the ethylene-propylene-nonconjugated diene copolymer crosslinked product (B1). The monomer mixture (B2) containing is added, and it heats suitably and is graft-polymerized.
Here, the ratio of the ethylene-propylene-nonconjugated diene copolymer crosslinked product (B1) to the total amount of the ethylene-propylene-nonconjugated diene copolymer crosslinked product (B1) and the monomer mixture (B2) is as follows: It is preferable that it is 10-90 mass%. When the ratio of the crosslinked ethylene-propylene-nonconjugated diene copolymer (B1) is 10% by mass or more (monomer mixture (B2) is less than 90% by weight), the resulting molded article has impact resistance. More improved. When the proportion of the crosslinked ethylene-propylene-nonconjugated diene copolymer (B1) is 90% by mass or less (monomer mixture (B2) exceeds 10% by mass), the resulting thermoplastic resin composition The fluidity of things becomes higher.

(V) After completion of the graft polymerization, an antioxidant is added if necessary, and then a coagulant is added to the obtained graft copolymer latex to solidify the resin solids. Examples of the coagulant include aqueous solutions of sulfuric acid, acetic acid, calcium chloride, calcium acetate, magnesium sulfate, and the like. One coagulant may be used alone, or two or more coagulants may be used in combination.
(Vi) The obtained resin solid is separated and washed with water, dehydrated and dried to obtain the graft copolymer (B).

  The content of the graft copolymer (B) is 4.9 to 80 parts by mass, preferably 15 when the total of (A), (B), (C) and (D) is 100 parts by mass. It is -90 mass parts. When the content of the graft copolymer (B) is 4.9 parts by mass or more, the impact resistance of the obtained molded product is improved, and when it is 80 parts by mass or less, fluidity and wear resistance are improved. improves.

[Carboxylic acid group-containing copolymer (C)]
The carboxylic acid group-containing copolymer (C) is a copolymer obtained by copolymerizing an unsaturated carboxylic acid monomer, an aromatic vinyl monomer, and a vinyl cyanide monomer.

Examples of the unsaturated carboxylic acid monomer that forms the carboxylic acid group-containing copolymer (C) include acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid. Of these, acrylic acid and methacrylic acid are particularly preferred from the viewpoint of solubility in other monomers during polymerization.
Moreover, an unsaturated carboxylic acid monomer may be used individually by 1 type, and may use 2 or more types together.
The aromatic vinyl monomer and vinyl cyanide monomer that form the carboxylic acid group-containing copolymer (C) are the same as those used in the production of the graft copolymer (B). Can be used.

The proportion of unsaturated carboxylic acid monomer units in the carboxylic acid group-containing copolymer (C) is preferably 0.05 to 20% by mass. If the ratio of the unsaturated carboxylic acid monomer unit is 0.05% by mass or more, the copolymer (C) is easily compatible with the polyamide (A). If it improves further and it is 20 mass% or less, fluidity | liquidity can be improved more.
The ratio of the aromatic vinyl monomer unit in the carboxylic acid group-containing copolymer (C) is preferably 90 to 50% by mass. The proportion of the vinyl cyanide monomer unit is preferably 9.95 to 45% by mass. When the aromatic vinyl monomer unit and the vinyl cyanide monomer unit are within the above ranges, the balance between fluidity and impact resistance is further improved.

In the carboxylic acid group-containing copolymer (C), a part of the aromatic vinyl monomer unit and the vinyl cyanide monomer unit may be copolymerized with other vinyl monomer units, For example, the methacrylic acid ester monomers such as methyl methacrylate and ethyl methacrylate exemplified as those used for the production of the graft copolymer (B), maleimide compounds such as N-phenylmaleimide and N-cyclohexylmaleimide, etc. It may be replaced.
Such other copolymerizable vinyl monomer units are preferably 0 to 40% by mass in the carboxylic acid group-containing copolymer (C).

The number average molecular weight of the carboxylic acid group-containing copolymer (C) is 20000 to 70000, preferably 25000 to 60000. When the number average molecular weight of the carboxylic acid group-containing copolymer (C) is 20000 or more, the impact resistance of the obtained molded product is improved, and when it is 70000 or less, the flow of the resulting thermoplastic resin composition Improves.
Here, the number average molecular weight of the carboxylic acid group-containing copolymer (C) is determined by dissolving the copolymer (C) in tetrahydrofuran, and using the obtained solution as a measurement sample, GPC (gel permeation chromatography) (Tosoh ( It is a value calculated by a standard polystyrene conversion method.

  The carboxylic acid group-containing copolymer (C) is produced by a known method such as a bulk polymerization method, a solution polymerization method, a bulk suspension polymerization method, a suspension polymerization method, or an emulsion polymerization method.

  The content of the carboxylic acid group-containing copolymer (C) is 0.1 to 20 parts by mass when the total of (A), (B), (C) and (D) is 100 parts by mass, Preferably it is 0.5-15 mass parts. When the content of the carboxylic acid group-containing copolymer (C) is 0.1 parts by mass or more, the impact resistance of the obtained molded product is improved, and when it is 20 parts by mass or less, the fluidity is improved. To do.

[Other polymer (D)]
The other polymer (D) is at least one selected from the group consisting of aromatic vinyl monomers, vinyl cyanide monomers, and other vinyl monomers copolymerizable with these monomers. The monomer component is polymerized. If the other polymer (D) contains the thermoplastic resin composition, the fluidity can be further improved and the dimensional stability can be improved.

As the aromatic vinyl monomer forming the other polymer (D), the same ones used for the production of the graft copolymer (B) can be used. Among them, styrene and / or α-methylstyrene is preferred.
As the vinyl cyanide monomer, those similar to those used for the production of the graft copolymer (B) can be used, and among these, acrylonitrile is preferable.
Other vinyl monomers exemplified as those used for the production of the graft copolymer (B) also for other vinyl monomers copolymerizable with aromatic vinyl monomers and vinyl cyanide monomers Monomers (excluding unsaturated carboxylic acid monomers) can be used.

The mass average molecular weight of the other polymer (D) is preferably 50,000 to 300,000, and more preferably 60000 to 250,000. If the mass average molecular weight of the other polymer (D) is 50000 or more, the impact resistance of the obtained molded product is further improved, and if it is 300000 or more, the fluidity of the obtained thermoplastic resin composition is further improved. To do.
Here, the mass average molecular weight of the other polymer (D) is determined by dissolving the polymer (D) in tetrahydrofuran, and using the obtained solution as a measurement sample, GPC (gel permeation chromatography) (manufactured by Tosoh Corporation) It is a value calculated by standard polystyrene conversion method.

  As a method for producing the other polymer (D), for example, known methods such as a bulk polymerization method, a solution polymerization method, a bulk suspension polymerization method, a suspension polymerization method, and an emulsion polymerization method are applied.

  The content of the other polymer (D) is more than 0 parts by mass and 40 parts by mass or less when the total of (A), (B), (C) and (D) is 100 parts by mass. preferable. If other polymer (D) is 40 mass parts or less, the effect by having mix | blended other polymer (D) will be exhibited, preventing the fall of the impact resistance of the molded article obtained.

The thermoplastic resin composition of the present invention may contain saturated polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyarylate, and polyolefins such as polycarbonate, polyphenylene oxide, polyphenylene sulfide, polyethylene, and polypropylene, if necessary. Good.
In addition, the thermoplastic resin composition of the present invention may contain additives such as antioxidants, lubricants, processing aids, pigments, fillers and the like, if necessary.

  As a method for producing the thermoplastic resin composition, for example, the components (A), (B), (C) and (D) are mixed with components added as necessary, for example, an extruder, Examples thereof include a method of kneading with a Banbury mixer, a kneading roll or the like to form a pellet.

  The above-mentioned thermoplastic resin composition is excellent in the balance between the impact resistance of the obtained molded product and the fluidity during molding, and is excellent in chemical resistance and wear resistance. This is because the polyamide (A) and the graft copolymer (B) which is an AES graft copolymer are compatible with each other with high compatibility by the carboxylic acid group-containing copolymer (C) whose molecular weight is specified. It is estimated that In particular, since the rubbery polymer constituting the graft copolymer (B) contains an acid-modified α-olefin copolymer, it is considered that the effect of improving the compatibility is sufficiently exhibited.

<Molded product>
The molded article of the present invention is formed by molding the above-described thermoplastic resin composition.
Examples of the molding method of the thermoplastic resin composition include an injection molding method, an extrusion molding method, a compression molding method, a vacuum molding method, and a blow molding method.
Since the molded article of the present invention is formed by molding the above thermoplastic resin composition, it is excellent in chemical resistance, abrasion resistance and impact resistance. Such a molded article is suitable for many uses such as automobiles, industrial articles such as electric / electronic / mechanical parts, sports / leisure articles, and the like.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following, “part” and “%” are based on mass.
Moreover, the average particle diameter in the following examples was measured by a dynamic light scattering method using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.).
Further, the number average molecular weight and the mass average molecular weight were measured by GPC (manufactured by Tosoh Corporation) using the obtained solution as a measurement sample by dissolving the polymer to be measured in tetrahydrofuran, and calculated by a standard polystyrene conversion method.
The viscosity average molecular weight is measured according to JIS K 7367-3 (1999), the solvent is decahydronaphthalene, and the temperature is 135 ° C.

[Polyamide (A)]
As polyamide (A), nylon-6 (1013B, Ube Industries, Ltd. number average molecular weight 13000) was used.

[Graft Copolymer (B-1)]
(Production Example 1)
(Production of latex of EPDM crosslinked product)
First, 100 parts of EPDM (trade name: TP3180, ethylene / propylene / diene ratio (mass%) = 70/28/2) manufactured by Mitsui Chemicals, Inc. was dissolved in 566 parts of n-hexane, and then Mitsui Chemicals, Inc. 12 parts of acid-modified polyethylene (trade name: high wax 2203A, viscosity average molecular weight: 2700, acid value: 30) was added, and 4.5 parts of oleic acid was further added and completely dissolved to prepare a polymer solution.
Separately, a potassium hydroxide aqueous solution in which 0.9 part of potassium hydroxide was dissolved in 700 parts of distilled water was prepared and heated to 60 ° C. The polymer solution was gradually added to the potassium hydroxide aqueous solution to emulsify, and then stirred with a homomixer. Next, part of the solvent and water was distilled off to obtain a latex having a particle size of 0.48 μm.
Next, 1.5 parts of divinylbenzene and 1.0 part of di-t-butylperoxytrimethylcyclohexane are added to 100 parts of EPDM, and the latex is reacted at 120 ° C. for 1 hour. Obtained. The average particle size of the latex of this EPDM crosslinked product was 0.48 μm. Further, the gel content of the EPDM crosslinked product was 70%.

The gel content was measured as follows.
First, the latex of the EPDM cross-linked product was coagulated with dilute sulfuric acid, washed with water and dried, then 0.5 g was collected and immersed in 200 ml of toluene at 115 ° C. for 5 hours. Next, the mixture was filtered through a 200 mesh stainless steel wire mesh, and the resulting residue was dried. After drying, the residue was weighed and the gel content was determined by the following formula.
Gel content (%) = [residue mass after drying / mass of sample before toluene immersion] × 100 (%)

(Production of graft copolymer)
EPDM cross-linked latex (as solids) 50 parts, dextrose 0.6 parts, ferrous sulfate, heptahydrate 0.01 parts, ethylenediaminetetraacetic acid sodium dihydrate 0.45 parts, pure water 150 parts A reactor equipped with a stirrer was charged.
Next, the temperature was raised to 80 ° C. with stirring, and 17 parts of acrylonitrile, 33 parts of styrene, and 1 part of cumene hydroperoxide were added dropwise over 150 minutes, and 1 part of potassium oleate and 30 parts of pure water were added for 180 minutes. Over the course of time, it was added dropwise.
After dropping, the mixture was further stirred for 1 hour to obtain a graft copolymer latex. The polymerization rate of this graft copolymer was 98.5%.

[Measurement of polymerization rate]
The polymerization rate of the graft copolymer was measured as follows.
A small amount of the reaction mixture was sampled from the reactor, and after measuring this mass, it was dried by heating with an infrared lamp, the mass of the remaining non-volatile content was measured, and determined by the following formula.
Polymerization rate [%] = (α × A ÷ B− (β + γ)) / ε × 100
α: Reaction mixture present in the container when collecting the reaction mixture [part]
A: Mass after heat drying of the collected reaction mixture B: Mass before heat drying of the collected reaction mixture β: Rubber polymer (a) (solid content) present in the container at the time of collecting the reaction mixture [part]
γ: Auxiliary raw material present in the container when collecting the reaction mixture
ε: Monomer mixture present in the container when the reaction mixture is collected [part]

  After the polymerization, a phenolic antioxidant (manufactured by API Corporation, trade name: Yoshinox 2246G) and a sulfur-based antioxidant (manufactured by API Corporation, trade name: DLTP “Yoshitomi”) were added. Subsequently, sulfuric acid was added to the latex to precipitate a resin solid, and the obtained resin solid was washed, dehydrated, and dried to obtain a graft copolymer (B-1) powder.

Production Example 2: Production of Graft Copolymer (B-2) In the production of graft copolymer (B-1) of Production Example 1, the amount of latex (as solids) of EPDM crosslinked product was 70 parts, and acrylonitrile A graft copolymer (B-2) was obtained in the same manner as in Production Example 1 except that the amount was changed to 10 parts and the amount of styrene was changed to 20 parts. The polymerization rate of this graft copolymer (B-2) was 99.5%.

Production Example 3: Production of Graft Copolymer (B-3) In production of the graft copolymer (B-1) of Production Example 1, the amount of latex (as a solid content) of EPDM crosslinked product was 90 parts, and acrylonitrile A graft copolymer (B-3) was obtained in the same manner as in Production Example 1 except that the amount was changed to 3 parts and the amount of styrene was changed to 7 parts. The polymerization rate of this graft copolymer (B-3) was 99.5%.

Production Example 4: Production of Graft Copolymer (B-4) In the production of the graft copolymer (B-1) of Production Example 1, the latex of the EPDM crosslinked product has a solid content concentration of 50% and an average particle size of 0. A graft copolymer (B-4) was obtained in the same manner as in Production Example 1, except that the polybutadiene latex was changed to 50 parts (as solid content) of 31 μm. The polymerization rate of this graft copolymer (B-4) was 98.5%.

Production Example 5 Production of Carboxylic Acid Group-Containing Copolymer (C-1) 200 parts of pure water, 0.3 part of potassium persulfate and 2 parts of sodium dodecylbenzenesulfonate were charged into a stainless steel container and the mixture was stirred at 65 ° C. The temperature rose. A monomer mixture consisting of 71 parts of styrene, 24 parts of acrylonitrile, 5 parts of methacrylic acid and 0.4 part of t-dodecyl mercaptan was continuously added thereto over 5 hours, and then the temperature in the container was raised to 70 ° C. Then, this temperature was maintained for 1 hour to complete the polymerization to obtain a polymer latex. The polymerization rate of this carboxylic acid group-containing copolymer (C-1) was 99.5%.

  Next, the polymer latex was coagulated with calcium acetate, dehydrated and dried to obtain a carboxylic acid group-containing copolymer (C-1). The number average molecular weight of the obtained carboxylic acid group-containing copolymer (C-1) was 45,000.

Production Example 6: Production of carboxylic acid group-containing copolymer (C-2) Production of carboxylic acid group-containing copolymer (C-1) was conducted except that t-dodecyl mercaptan was changed to 0.1 part. In the same manner as in Example 5, a carboxylic acid group-containing copolymer (C-2) was obtained. The polymerization rate of this carboxylic acid group-containing copolymer (C-2) was 99.5%. Moreover, the number average molecular weight of the obtained carboxylic acid group containing copolymer (C-2) was 81000.

Production Example 7: Production of carboxylic acid group-containing copolymer (C-3) Production example of carboxylic acid group-containing copolymer (C-1) except that t-dodecyl mercaptan was changed to 1.5 parts. In the same manner as in Example 5, a carboxylic acid group-containing copolymer (C-3) was obtained. The polymerization rate of this carboxylic acid group-containing copolymer (C-3) was 99.5%. Moreover, the number average molecular weight of the obtained carboxylic acid group containing copolymer (C-3) was 19000.

Production Example 8 Production of Carboxylic Acid Group-Containing Copolymer (C-4) In the production of the carboxylic acid group-containing copolymer (C-1), the amount of styrene was 74.25 parts and the amount of acrylonitrile was 24.75. A carboxylic acid group-containing copolymer (C-4) was obtained in the same manner as in Production Example 5 except that the amount of methacrylic acid was changed to 1 part. The polymerization rate of this carboxylic acid group-containing copolymer (C-4) was 99.5%. Moreover, the number average molecular weight of the obtained carboxylic acid group containing copolymer (C-4) was 49000.

Production Example 9 Production of Carboxylic Acid Group-Containing Copolymer (C-5) In the production of the carboxylic acid group-containing copolymer (C-1), the amount of styrene was 67.5 parts and the amount of acrylonitrile was 22.5. The carboxylic acid group-containing copolymer (C-5) was obtained in the same manner as in Production Example 5 except that the amount of methacrylic acid was changed to 10 parts. The polymerization rate of this carboxylic acid group-containing copolymer (C-5) was 99.5%. Moreover, the number average molecular weight of the obtained carboxylic acid group containing copolymer (C-5) was 42000.

Production Example 10: Production of other polymer (D) 120 parts of water, 0.5 parts of polyvinyl alcohol, 0.3 parts of azobisisobutyronitrile, 0.35 parts of t-dodecyl mercaptan, in a nitrogen-substituted reactor A monomer mixture consisting of 27 parts of acrylonitrile and 73 parts of styrene was added. Then, after heating for 5 hours at a temperature of 60 ° C. in the reactor, the temperature was raised to 120 ° C. and the reaction was performed for 4 hours. A part of the reaction solution thus obtained was collected, and the residual monomer was obtained and calculated using gas chromatography. As a result, the polymerization rate of this copolymer was 99.8%.
The obtained reaction solution was cooled, washed, dehydrated and dried to obtain another polymer (D) in the form of beads. The obtained polymer (D) had a mass average molecular weight of 120,000.

Examples 6 and 7, Reference Examples 1 to 5 , 8 to 10 , Comparative Examples 1 to 7
Tables 1 and 2 show polyamides (A), graft copolymers (B-1 to B-4), carboxylic acid group-containing copolymers (C-1 to C-5), and other polymers (D). The mixture was mixed at the indicated ratio, melt-mixed at 260 ° C. using a 30 mm twin screw extruder (“TEX30α” manufactured by Nippon Steel Works, Ltd.), and pelletized. Thereafter, the obtained pellets were molded at a molding temperature of 260 ° C. by a 75-ton injection molding machine (“J75EII-P” manufactured by Nippon Steel Works). The physical properties of the molded products were evaluated by the following methods. The results are shown in Tables 1 and 2.

(Liquidity)
Using a spiral flow mold (width 15 mm × thickness 2 mm), a thermoplastic resin composition is injected from an injection molding machine under conditions of a cylinder temperature of 260 ° C., a mold temperature of 80 ° C., and a pressure of 7.4 MPa. The length [mm] was measured.
(Charpy impact strength)
In accordance with ISO 179, the measurement was performed at measurement temperatures of 23 ° C. and −30 ° C.
(Surface impact strength)
Using a high-speed impact tester (HTM-1 manufactured by Shimadzu Corporation), a flat test piece (100 × 100 × 3 mm) produced by injection molding, with a tip diameter of 1/2 inch in an environment of 23 ° C. The round missile was dropped at a speed of 5.0 m / sec. And the fracture energy [kJ] was computed from the area of the stress-strain curve until a test piece fractures.
(chemical resistance)
A strip-shaped test piece (150 × 10 × 2 mm) produced by injection molding was fixed along a bending foam method test jig having a surface with a gradually changing curvature. Next, a chemical solution was applied to the test piece and left in an environment at 23 ° C. for 48 hours. Then, the occurrence of craze and cracks in the test piece was confirmed, and the critical strain [%] was determined from the curvature of the test jig. As chemicals, plasticizer: di-2-ethylhexyl phthalate (DOP), general-purpose brake oil: DOT-4 (Honda Motor Co., Ltd.), toilet detergent: Toilet Powers (Esthe Chemical Co., Ltd.) were used.
(Abrasion resistance)
In accordance with ASTM D-1044, a Taber test (wear wheel: CS-) was performed on a flat test piece (100 × 100 × 3 mm) produced by injection molding using a Taber abrasion tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.). 17 · load: 1000 g · 1000 rotations), and the amount of wear [mg] was measured.

As shown in Table 1, Examples 6 and 7 and Reference Examples 1 to 5 and 8 containing polyamide (A), graft copolymer (B) and carboxylic acid group-containing copolymer (C) as essential components. The thermoplastic resin composition of 10 to 10 was excellent in the balance between fluidity and impact resistance, and also excellent in chemical resistance and abrasion resistance.
In contrast, the thermoplastic resin composition of Comparative Example 1 made of polyamide (A) had low impact resistance.
The thermoplastic resin composition of Comparative Example 2 that did not contain the polyamide (A) and the carboxylic acid group-containing copolymer (C) had low chemical resistance.
The thermoplastic resin composition of Comparative Example 3 that did not contain the carboxylic acid group-containing copolymer (C) had low impact resistance.
The thermoplastic resin composition of Comparative Example 4 in which the content of the carboxylic acid group-containing copolymer (C) exceeded 20 parts had low fluidity.
The thermoplastic resin composition of Comparative Example 5 in which the graft copolymer (C) was replaced with an ABS graft copolymer had low chemical resistance.
The thermoplastic resin composition of Comparative Example 6 in which the number average molecular weight of the carboxylic acid group-containing copolymer (C) exceeded 70000 had low fluidity.
The thermoplastic resin composition of Comparative Example 7 in which the number average molecular weight of the carboxylic acid group-containing copolymer (C) was less than 20000 had low impact resistance.

Claims (3)

70 to 90 parts by mass of polyamide (A),
An aromatic vinyl monomer and a vinyl cyanide monomer are added to a rubber-like polymer including an acid-modified α-olefin copolymer having a viscosity average molecular weight of 1000 to 9000 and an ethylene-propylene-nonconjugated diene copolymer. 8-25 parts by mass of a graft copolymer (B) obtained by polymerization,
Carboxylic acid group-containing copolymer (C) having a number average molecular weight of 20,000 to 70,000 obtained by copolymerizing an unsaturated carboxylic acid monomer, an aromatic vinyl monomer and a vinyl cyanide monomer 2 to 5 mass (However, the sum of the above (A), (B) and (C) is 100 parts by mass). The carboxylic acid group-containing copolymer (C) is a polymer latex obtained by emulsion copolymerization of an unsaturated carboxylic acid monomer, an aromatic vinyl monomer, and a vinyl cyanide monomer. The thermoplastic resin composition according to claim 1, which is a polymer obtained by coagulation by addition .   A molded article, wherein the thermoplastic resin composition according to claim 1 or 2 is molded.