JP5810619B2 - Thermoplastic resin composition and molded article thereof - Google Patents

Description

Detailed Description of the Invention

TECHNICAL FIELD OF THE INVENTION

  The present invention relates to a thermoplastic resin composition and a molded body thereof, and particularly relates to a thermoplastic resin composition excellent in paint adhesion and a molded body thereof.

  Polyamide resins are excellent in heat resistance, chemical resistance, weather resistance, mechanical properties, electrical properties, etc., and are therefore used in many industrial applications as injection molding materials, fibers, and films. However, due to the high crystallinity, when a molded product with a small thickness or a molded product with a non-uniform thickness and a complicated shape is injection-molded, warping may occur and the molded product may be deformed or sinks may occur. When the appearance is damaged, or when the water absorption is high, mechanical properties and heat resistance are deteriorated, the molded body is deformed, and further, there are problems such as poor coating and poor adhesion of molded products.

  For such problems, generally improvements by blending various inorganic particles, alloying with amorphous resins such as polycarbonate resins, styrene resins, polyphenylene resins, glass fibers, carbon fibers, various Attempts have been made to improve material properties by adding fillers.

  In addition, as a method for alloying a polyamide resin and a styrene resin, a blend with an ABS resin, that is, a method for improving compatibility with a polyamide / ABS alloy or ABS resin, an unsaturated carboxylic acid together with styrene and acrylonitrile is used. A method of blending a modified copolymer obtained by polymerization is disclosed.

  Furthermore, a method by alloying with an inorganic filler and a specific styrene resin is disclosed.

  For example, Patent Document 1 discloses PA resin 90 to 65% by weight and PP resin as a heat resistant resin composition suitable for injection molding excellent in heat resistance, strength, rigidity, low water absorption, surface smoothness, and bake coatability. Disclosed is a heat resistant resin composition containing 2.2 to 10 parts by weight of a compatibilizing agent and 20 to 100 parts by weight of wollastonite with respect to 100 parts by weight of a PA / PP resin comprising 10 to 35% by weight. Yes. Among them, wollastonite has an average fiber diameter of 3 to 15 μm and an average aspect ratio of 1 to 14. Also, first, PP resin and wollastonite are kneaded to obtain master pellets, then master pellets, PA resin and compatibilizing agent are kneaded and injection molded to obtain a molded product. It is also disclosed that a paint film is formed by baking and an epoxy resin is included in consideration of weather resistance.

  However, the above method can ensure sufficient adhesion between the substrate and the coating film immediately after coating, but there are cases where practical coating quality and durability may not be obtained due to water absorption etc. There was a need for improvement.

JP 08-269323 A

  An object of the present invention is to improve such a conventional problem and to provide a thermoplastic resin composition having excellent long-term paint adhesion.

  As a result of diligent studies to achieve the above object, the present inventors have dispersed acicular wollastonite that has been subjected to a hydrophobic surface treatment in a resin composition comprising a polyamide resin and a styrene resin. Thus, the present inventors have completed a resin molded article having excellent coating adhesion, which is made of a thermoplastic resin composition having excellent heat resistance and coating adhesion.

That is, the present invention includes a base resin 100 containing a polyamide resin 21-79 parts by weight, and one or more styrene-based resin 21 to 79 parts by weight selected from the group consisting of unsaturated carboxylic acid-modified ABS resin and polystyrene, Thermoplastic resin containing 5 to 25 parts by weight of wollastonite that has been subjected to a hydrophobized surface treatment with at least one hydrophobizing agent selected from the group consisting of vinylsilazane and hexamethyldisilazane Relates to the composition.

  A preferred embodiment is that the wollastonite subjected to the hydrophobized surface treatment is acicular wollastonite having a needle-like shape.

  A preferred embodiment is that the average fiber diameter of wollastonite subjected to the hydrophobized surface treatment is 20 μm or less.

  Moreover, this invention relates to the molded object formed by shape | molding the thermoplastic resin composition of this invention.

  As described in detail above, by dispersing the thermoplastic resin composition containing the acicular wollastonite that has been subjected to the hydrophobic surface treatment of the present invention in a resin composition comprising a polyamide resin and a styrene resin. A thermoplastic resin composition having excellent coating film adhesion and excellent heat resistance is provided.

(Thermoplastic resin composition)
The thermoplastic resin composition of the present invention is composed of 100 parts by weight of a base resin containing 21 to 79 parts by weight of a polyamide resin and 21 to 79 parts by weight of a styrene resin, and 5 to 5 of wollastonite that has been subjected to a hydrophobic surface treatment. It is a thermoplastic resin composition having excellent paint film adhesion containing 25 parts by weight and excellent heat resistance.

  In the thermoplastic resin composition of the present invention, the content of wollastonite subjected to the hydrophobized surface treatment according to the present invention is 5 to 25 parts by weight with respect to 100 weight of the base resin according to the present invention. However, from the viewpoint of securing sufficient coating adhesion while increasing the strength such as the flexural modulus and bending strength, it is preferably 10 to 25 weights.

(Base resin)
The base resin according to the present invention contains 21 to 79 parts by weight of a polyamide resin and 21 to 79 parts by weight of a styrene resin, but can be further added by including other resins in the range of 0 to 20 parts by weight. It is also preferable to provide such functions.

  While the polyamide resin has high heat resistance and mechanical strength, it has only low coating film adhesion, and in order to compensate for this point and provide coating film adhesion, the styrenic resin is used in the present invention. Used together.

  The base resin according to the present invention is subjected to the hydrophobized surface treatment according to the present invention while satisfying both the heat resistance and mechanical strength derived from the above-mentioned polyamide resin and the coating film adhesion derived from the styrene resin. From the viewpoint of sufficiently exhibiting the effect of improving the long-term paint adhesion characteristically obtained by the addition of wollastonite formed, 100 parts by weight of the base resin is 25 to 75 parts by weight of the polyamide resin and 25 of the styrene resin 25 -75 parts by weight, preferably 30-70 parts by weight of polyamide resin, and more preferably 30-70 parts by weight of styrene resin, more preferably 40-60 parts by weight of polyamide resin, and 40 of styrene resin 40. -60 parts by weight, particularly preferably 50-60 parts by weight of polyamide resin and 40-50 parts by weight of styrene resin. Is that Unisuru.

(Polyamide resin)
The polyamide resin used in the present invention is a polymer that contains an amide bond (—NHCO—) in the main chain and can be melted by heating. Specific examples include polycaproamide (nylon 6), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebamide (nylon 610), polyhexamethylene dodeca Mido (nylon 612), polyundecane methylene adipamide (nylon 116), polyundecanamide (nylon 11), polydodecanamide (nylon 12), polytrimethylhexamethylene terephthalamide (nylon TMHT), polyhexamethylene isophthalamide (Nylon 6I), polyhexamethylene terephthalate / isophthalamide (nylon 6T / 6I), polybis (4-aminocyclohexyl) methane dodecamide, (nylon PACM12), polybis (3-methyl-4-aminocyclo) Xyl) methane dodecamide (nylon dimethyl PACM12), polymetaxylylene adipamide (nylon MXD6), polyundecamethylene terephthalamide (nylon 11T), polyundecamethylene hexahydroterephthalamide (nylon 11T (H)), and These copolyamides, mixed polyamides and the like are available.

  Among these, from the viewpoints of heat resistance, impact resistance and chemical resistance, nylon 6, nylon 46, nylon 66, nylon 11, nylon 12, nylon 46, MXD nylon, aromatic polyamide resins, and their copolymer polyamides And at least one selected from the group consisting of mixed polyamides, more preferably 1 selected from the group consisting of nylon 6, nylon 66, nylon 46, and MXD nylon from the viewpoint of strength, elastic modulus, cost, and the like. More than a seed.

  Although there is no restriction | limiting in particular as the molecular weight of a polyamide resin, Usually, the thing of the range whose relative viscosity measured in 25 degreeC concentrated sulfuric acid is 0.5-5.0 is used preferably. Furthermore, two or more types having different relative viscosities can be used in combination.

(Styrene resin)
Examples of the styrene resin used in the present invention include polystyrene, rubber-modified polystyrene (HIPS resin), styrene-acrylonitrile copolymer, styrene-rubber polymer-acrylonitrile copolymer (ABS resin, AES resin, AAS resin). , ACS resin) and the like, and these may be used in combination of two or more. Furthermore, some or all of these styrene and acrylonitrile are α-methylstyrene, p-methylstyrene, pt-butyl. styrene,
(Meth) acrylic acid ester compounds such as methyl, ethyl, propyl, n-butyl,
Examples thereof include those substituted with a vinyl monomer copolymerizable with styrene, such as maleimide monomers such as maleimide, N-methylmaleimide, N-cyclohexylmaleimide and N-phenylmaleimide.

  Among these styrenic resins, from the viewpoint of impact strength, ABS resin, polystyrene, HIPS resin, AES resin, AAS resin, ACS resin, MBS resin, etc. are preferably used, and more preferably a part of styrene is used. A carboxylic acid group-containing ABS resin substituted with an unsaturated carboxylic acid monomer, that is, at least one selected from the group consisting of an unsaturated carboxylic acid-modified ABS resin and polystyrene, and the physical properties of the thermoplastic resin composition of the present invention From the viewpoint of balance and compatibility with polyamide, from an economical viewpoint, it is more preferably an unsaturated carboxylic acid-modified ABS resin, particularly preferably an unsaturated carboxylic acid monomer among the unsaturated carboxylic acid-modified ABS resins. And at least one selected from the group consisting of methacrylic acid, maleic acid, fumaric acid, and itaconic acid. A carboxylic acid group-containing ABS resin obtained by substituting down, most preferably methacrylic acid residue-containing ABS resin was replaced with methacrylic acid.

  There is no restriction | limiting in the manufacturing method of such a styrene resin, Ordinary methods, such as a block polymerization method, a suspension polymerization method, an emulsion polymerization method, a block-suspension polymerization method, can be used.

  As the unsaturated carboxylic acid-modified ABS resin, compatibility with polyamide, chemical resistance, heat resistance, impact resistance, molding processability, thermal stability during molding process, suppression of coloring during heating, surface of molded article From the viewpoints of suppressing layer peeling of these materials and balancing these, 40 to 80% by weight of the aromatic vinyl compound, 15 to 50% by weight of the vinyl cyanide compound, 0.1 to 20% by weight of the unsaturated carboxylic acid compound, and other co-polymers. Unsaturated carboxylic acid-containing copolymer which is a polymer of a monomer composed of 0 to 30% by weight of a polymerizable vinyl compound, and 30 to 95% by weight of a diene rubber having a volume average particle diameter of 0.01 to 5.0 μm. A graft copolymer-containing unsaturated carboxylic acid-modified ABS composed of a graft copolymer obtained by graft polymerization of 70 to 5% by weight of a vinyl compound in the presence of 1% by weight is preferable.

  The mixing ratio of the unsaturated carboxylic acid-containing copolymer and the graft copolymer is usually 80% by weight: 20% by weight to 20% by weight: 80% by weight, but 75% by weight: 25% by weight It is preferably 25% by weight: 75% by weight.

(Graft copolymer-containing unsaturated carboxylic acid-modified ABS)
As described above, the graft copolymer-containing unsaturated carboxylic acid-modified ABS is composed of an unsaturated carboxylic acid-containing copolymer and a graft copolymer. There are a method of obtaining a dry resin after mixing the latex of the polymer and graft copolymer (latex mixing), and a method of obtaining these separately as a resin and mixing them in a powder state, but retains the characteristics as an ABS resin. However, from the viewpoint of developing high compatibility with the polyamide resin, it is preferable to be manufactured by the latex mixing.

  A method for obtaining a dry resin from the obtained latex may be a known method, but specifically, an acid such as hydrochloric acid, sulfuric acid or acetic acid, or a metal salt such as calcium chloride, magnesium chloride or aluminum sulfate is usually added to the latex. The latex is coagulated and then dehydrated and dried.

  Examples of the aromatic vinyl compound used for the polymerization of the unsaturated carboxylic acid-containing copolymer include styrene, α-methylstyrene, chlorostyrene, and methylstyrene. In particular, α-methylstyrene is preferably used from the viewpoint of improving heat resistance. Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile. Examples of the unsaturated carboxylic acid compound include acrylic acid and methacrylic acid. Examples of other copolymerizable vinyl compounds include methacrylic acid such as methyl methacrylate, ethyl methacrylate, methyl acrylate and ethyl acrylate, alkyl esters of acrylic acid, and maleimide compounds such as maleimide and phenylmaleimide. Is done. The above aromatic vinyl compound, vinyl cyanide compound, unsaturated carboxylic acid compound, and other copolymerizable vinyl compounds are used alone or in combination of two or more.

  The unsaturated carboxylic acid-containing copolymer can be produced, for example, as follows. That is, α-methylstyrene is first charged with water and an emulsifier, and after sufficiently emulsified, acrylonitrile and other monomers are continuously added dropwise in small amounts, and α-methylstyrene is always in the polymerization system. By making the α-methylstyrene large excess of 80% by weight or more, preferably 90% by weight or more, the desired copolymer can be obtained. In this case, the unsaturated carboxylic acid compound may be previously charged together with α-methylstyrene or may be added by mixing with acrylonitrile. It is also possible to divide into pre-charge and additional charge. A part of α-methylstyrene can also be added. In this case, the amount of α-methylstyrene charged first is preferably 50 parts by weight or more and 90 parts by weight or less of 100 parts by weight of all monomers. When the copolymer is produced, if the amount of α-methylstyrene exceeds 90% by weight, chemical resistance and impact resistance are lowered, and if it is less than 60% by weight, the heat distortion resistance may be lowered.

  From the viewpoint of impact resistance and oil resistance, the graft copolymer is a vinyl compound 70 that can be copolymerized in the presence of 30 to 95% by weight of a diene rubber having a volume average particle diameter of 0.01 to 5.0 μm. A graft copolymer obtained by graft copolymerization of ˜5% by weight is preferably used. As the vinyl copolymer capable of graft copolymerization, aromatic vinyl compounds, vinyl cyanide compounds, unsaturated carboxylic acid alkyl ester compounds, unsaturated carboxylic acid compounds and other vinyl compounds can be used. The same aromatic vinyl compound, vinyl cyanide compound, and unsaturated carboxylic acid compound as those used in the unsaturated carboxylic acid-containing copolymer can be used. Examples of unsaturated carboxylic acid alkyl ester compounds include methyl methacrylate, ethyl methacrylate, methyl acrylate, and ethyl acrylate. Other copolymerizable vinyl compounds include maleimide compounds such as maleimide and phenylmaleimide. Any of these may be used alone or in combinations of two or more.

  The diene rubber preferably has a volume average particle size of 0.01 to 5.0 μm, more preferably 0.02 to 2.m, from the viewpoint of excellent impact resistance and appearance of the molded body. It is to be 0 μm. Furthermore, for the purpose of improving impact strength, a diene rubber latex obtained by agglomerating and enlarging a small particle diene rubber latex can be used. As a method for agglomerating and enlarging the small particle diene rubber latex, a conventionally known method such as a method of adding an acidic substance, a method of adding an acid group-containing latex, or the like can be employed, and there is no particular limitation.

  The unsaturated carboxylic acid-containing copolymer and the graft copolymer are preferably obtained by emulsion polymerization, but are not necessarily limited to emulsion polymerization. Examples include bulk polymerization, suspension polymerization, solution polymerization, and combinations thereof, that is, emulsion-suspension polymerization, emulsion-bulk polymerization. An ordinary method can be applied to the emulsion polymerization. That is, the compound may be reacted in an aqueous medium in the presence of a radical initiator. In that case, the said compound may be used as a mixture, and may be divided | segmented and used as needed. Further, the method of adding the compound may be charged all at once or may be added sequentially, and is not particularly limited.

(Other resins)
The thermoplastic resin composition having excellent paint adhesion of the present invention includes, as necessary, polybutadiene, acrylic rubber, ionomer, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, natural rubber, chlorination. Butyl rubber, α-olefin homopolymer, copolymer of two or more α-olefins (including any copolymer such as random, block, graft, etc., or a mixture thereof), or olefinic Impact modifiers such as elastomers can be added as other resins. These may be modified with an acid compound such as maleic anhydride or an epoxy compound such as glycidyl methacrylate. In addition, any other thermoplastic resin or thermosetting resin, for example, epoxy resin, unsaturated polyester resin, polyester carbonate resin, liquid crystal polyester resin, polyolefin resin, thermoplastic, as long as the properties such as mechanical properties are not impaired. A polyester resin, a polyphenylene sulfide resin, a polyphenylene ether resin, a polyacetal resin, a polysulfone resin, a polyarylate resin, or the like may be added alone or in combination of two or more as other resins.

(Wollastonite with hydrophobized surface treatment)
The wollastonite according to the present invention is an inorganic filler that is also called wollastonite and is represented by CaSiO ₃ , and has hydrophilicity due to a hydroxyl group present on the surface before the hydrophobization treatment. By treating such wollastonite with a hydrophobizing agent (ie, attaching a hydrophobizing agent to the surface), the hydroxyl group is replaced with a hydrophobic group such as an alkyl group or a fluorinated alkyl group. Thus, the wollastonite (hereinafter, hydrophobized wollastonite) that has been subjected to the hydrophobizing treatment according to the present invention has been changed to a hydrophobic surface.

  The degree of modification from hydrophilicity to hydrophobicity can generally be evaluated by the contact angle. In the present invention, a case where the contact angle is less than 90 degrees can be defined as “hydrophilic”, and a case where the contact angle is 90 degrees or more can be defined as “hydrophobic”. The contact angle of a “hydrophilic” surface having a Si—OH group (such as a glass surface) is usually about 30 degrees.

  The wollastonite is a wollastonite obtained by treating a powdery state with a hydrophobizing agent and performing the hydrophobizing treatment according to the present invention, but the wollastonite of the thermoplastic resin composition of the present invention is used. The wollastonite that has been subjected to the hydrophobization treatment used in the production is also kneaded with the base resin in a powder state to form the resin composition of the present invention.

  As a method for measuring the contact angle of the hydrophobized wollastonite in such a powder state, the powder is pelletized by applying pressure, and then water is dropped on the pellet to form water droplets. It is possible by measuring the contact angle.

  As the wollastonite, there are acicular and lump-like crystal structures, and as the wollastonite of the hydrophobized wollastonite according to the present invention, acicular wollastonite having an acicular shape is resistant. It is preferable from the viewpoint of impact strength and heat resistance. From the viewpoint of the appearance of the green body, the needle-like number average fiber diameter is preferably 20 μm to 1 μm, more preferably 10 μm to 0.5 μm.

  The hydrophobizing agent of the present invention refers to an agent that increases the hydrophobicity of wollastonite by adhering to the surface of wollastonite. As the hydrophobizing agent, at least one selected from the group consisting of a silane coupling agent and a titanium coupling agent is preferably used. Among them, a silane coupling agent is preferable, and among them, from the viewpoint of hydrophobicity imparting power. , Vinylsilazane, and one or more selected from the group consisting of hexamethyldisilazane are more preferable, and hexamethyldisilazane is more preferable.

  Examples of the silane coupling agent include hexamethyldisilazane, vinylsilazane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, trimethylalkoxysilane, dimethyldialkoxysilane, methyltrialkoxysilane, trimethylmethoxysilane, dimethyldimethoxysilane, methyl Examples include trimethoxysilane, hexamethyltriethoxysilane, and hexamethyltrimethoxysilane. Among these, hexamethyldisilazane and vinylsilazane are preferable.

As the hydrophobizing treatment method, wet or dry hydrophobizing treatment is used. For example, in the case of wet hydrophobizing treatment, a hydrophobizing agent is introduced into an arbitrary solvent such as toluene or xylene. Then, the surface treatment is performed by adding a solvent containing a hydrophobizing agent to wollastonite, and the hydrophobizing agent is deposited on the surface of the acicular wollastonite. Thereafter, the wollastonite is separated from the solvent using a technique such as filtration or centrifuge, and then the solvent is separated by heating and drying using an apparatus such as a fluid dryer. Then, acicular wollastonite having a surface treated with a hydrophobizing agent can be obtained. As a dispersion apparatus used in the hydrophobization treatment by wet, a medium stirring mill such as an ultrasonic disperser and a bead mill can be applied.
The contact angle of wollastonite that has been subjected to a hydrophobic surface treatment is preferably 100 degrees or more.

(Other additives)
Furthermore, additives such as pigments, dyes, heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, lubricants, plasticizers, flame retardants, and antistatic agents can be added depending on the purpose.

(Kneading)
There are no particular restrictions on the method for producing a resin molded article having excellent coating adhesion comprising the thermoplastic resin composition of the present invention. For example, a polyamide resin and a styrene resin, or a needle-shaped wax treated with a hydrophobic surface treatment is used. Examples thereof include a method of melt kneading the lastite using various general kneaders. Examples of the kneader include a single screw extruder, a twin screw extruder, a roll, a Banbury mixer, and a kneader. The polyamide resin, the styrene resin, and the needle-shaped wollastonite that has been subjected to the hydrophobic direction treatment may be put into the kneader and melt-kneaded together, or the polyamide resin and the styrene resin may be melted in advance. Thereafter, it may be added and kneaded.

(Molding / Use)
The resin molded article having excellent coating adhesion comprising the thermoplastic resin composition obtained in the present invention may be molded by injection molding or hot press molding, and can also be used for blow molding. The resulting molded product has excellent appearance, heat resistance, paint adhesion, etc., and the paint can use common paints such as acrylic urethane, single layer coating such as primer only, undercoat only, Furthermore, since it is not limited to the type of paint and the number of coating layers, such as multilayer coating with multiple layers of primer and undercoat, for example, automotive parts, household electrical appliance parts, household It is suitably used for daily necessities, packaging materials, and other general industrial materials.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

  Below, the main raw material used by an Example and a comparative example is shown collectively. Unless otherwise noted, the raw materials are not purified.

(Base resin)
As polyamide resin A, nylon 6 resin (Unitika nylon 6 A1020BRL (manufactured by Unitika Ltd.)) was used.

  As the styrene resin B, the ABS resin obtained in Reference Example 1 below was used.

(Filler)
Filler C: Wollastonite Product Name Nigros 4W Needle-shaped wollastonite with a diameter of 4.5 μm has a contact angle of 20 degrees or less (manufactured by NYCO).
As the filler E, the hydrophobic wollastonite obtained in Reference Example 2 using the filler C, that is, the above-mentioned Nigros 4W, was used.

(Reference Example 1: Production of ABS resin)
In order to prepare an unsaturated carboxylic acid-containing copolymer (I), 250 parts by weight of water, 0.4 parts by weight of sodium formaldehyde sulfoxylate in a nitrogen stream in a reaction vessel having a stirrer and a reflux condenser, 0.0025 parts by weight of ferrous sulfate, 0.01 parts by weight of disodium ethylenediaminetetraacetate and 2.0 parts by weight of sodium dioctylsulfosuccinate were charged and heated to 60 ° C. with stirring.

  Thereafter, while continuing stirring, a vinyl monomer mixture 100 comprising 75 parts by weight of α-methylstyrene (α-MeSt), 20 parts by weight of acrylonitrile (AN), and 5 parts by weight of methacrylic acid (MAA). Continuously over 6 hours with 0.3 parts by weight of cumene hydroperoxide (CHP) as an initiator and 0.5 parts by weight of t-dodecyl mercaptan (t-DM) as a polymerization degree regulator. Added dropwise. After completion of the dropwise addition, stirring was further continued at 60 ° C. for 1 hour to complete the polymerization, and an unsaturated carboxylic acid-containing copolymer (I) was obtained.

  Separately from the production of the unsaturated carboxylic acid-containing copolymer (I), a stirrer and a reflux condenser were used to produce the polybutadiene rubber particles (X) used for producing the graft copolymer (filter). In a nitrogen stream, water 250 parts by weight, potassium persulfate 0.5 parts by weight, butadiene 100 parts by weight, t-DM 0.3 parts by weight, and disproportionated sodium rosinate 3.0 parts by weight. The mixture was heated and maintained at 60 ° C. while charging and stirring, and the polymerization was continued at a polymerization temperature of 60 ° C. When the polymerization rate of butadiene reached 80%, the polymerization was stopped to remove unreacted butadiene, and polybutadiene rubber particles (X) having a volume average particle size of 0.30 μm were obtained in a latex state.

  Next, in order to prepare the graft copolymer (filter), the polybutadiene rubber particles (X) obtained above (solid content, that is, moisture, etc.) in a nitrogen stream in a reaction vessel having a stirrer and a reflux condenser. 70 parts by weight), 250 parts by weight of water, 0.4 parts by weight of sodium formaldehyde sulfoxylate, 0.0025 parts by weight of ferrous sulfate, and 0.01 parts by weight of disodium ethylenediaminetetraacetate The mixture was heated to 60 ° C. with stirring.

  Then, while continuing stirring, 30 parts by weight of a vinyl monomer mixture composed of 10 parts by weight of styrene (St) and 20 parts by weight of methyl methacrylate (MMA) was added to 0.3 parts by weight of CHP and t- It was continuously added dropwise together with 0.2 parts by weight of DM over 5 hours. After completion of the dropping, stirring was further continued at 60 ° C. for 1 hour to complete the polymerization, and a latex of a graft copolymer (filter) was obtained.

  An ABS resin was produced by the method described below using the unsaturated carboxylic acid-containing copolymer (ii) and the graft copolymer (filter) obtained above. That is, 64 parts by weight of an unsaturated carboxylic acid-containing copolymer (I) (as a solid content) and 36 parts by weight of a graft copolymer (filter) (as a solid content) were mixed uniformly in a latex state. A phenolic antioxidant was added to the solution, and then solidified with an aqueous magnesium chloride solution. Thereafter, it was washed with water, dehydrated and dried to obtain an ABS resin.

(Reference Example 2)
In a container having a stirrer, 50 parts by weight of toluene and 1 part by weight of hexamethyldisilazane [(CH ₃ ) ₃ Si] ₂ NH (TSL8802 manufactured by Momentive Performance Materials Japan LLC) are charged at room temperature. Then, the mixture was stirred and dispersed for 15 minutes with a stirring blade. Thereafter, 100 parts by weight of Nigros 4W was added thereto, followed by further stirring for 15 minutes, and toluene and TSL8802 were deposited on the surface of Nigros 4W. Thereafter, Nigros 4W is separated from the solvent component using a filter, and further, the remaining solvent component is separated by heating and drying for 24 hours in a hot air circulating drying at 50 ° C., so that the surface has a hexagonal surface. Nigros 4W treated with methyldisilazane was obtained. The hydrophobized wollastonite powder was compressed into a pellet having a diameter of 12 mm and a thickness of 2 mm by compressing the pressure of 70 MPa for 10 minutes using a tablet molding apparatus (Shimadzu Corporation). After that, water was dropped on the pellet with a syringe to form water droplets, and the contact angle was measured with a contact angle meter (Kyowa Interface Science Co., Ltd., CAS-150 type), which was 125 degrees.

(Bending characteristics)
Using a bending tester (Toyo Seiki Co., Ltd., STROGRAPH API II) installed in a constant temperature and humidity chamber (23 ° C., 50% RH) according to ASTM D-790, the bending strength and bending elastic modulus of the bar-shaped test piece are used. Measured at a test speed of 5 mm / min.

(Load deflection temperature)
The deflection temperature bending characteristic of the bar-shaped test piece at a load of 0.45 MPa was measured using a load deflection tester (Yasuda Seiki Seisakusho) according to ASTM D-648.

(Appearance of molded product)
The surface of the flat test piece was visually observed, and the surface smoothness was evaluated from the reflection of a fluorescent lamp, the degree of light reflection, and the uneven state. Here, the case where the surface appearance was smooth was evaluated as ◯, and the case where the surface appearance was conspicuous was evaluated as ×.

(Coating primary adhesion)
A flat test piece was used, and after degreasing one surface of the flat test piece, a paint was applied, baked, and cured to prepare a sample for primary adhesion evaluation. Specifically, as a paint, as a primer, urethane resin-based paint manufactured by BASF Corp., Primemac No. 1800 KHI-D, urethane resin paint BASF, HU60 SH8-EBY was used as the undercoat, and urethane resin paint BASF, HU80 C HS-CLR KA-5 was used as the top coat. . For spraying each paint, a gravity spray gun (Lansberg Industry, TSG-508G) using compressor air (air pressure, 0.8 MPa) via a dehumidifying dryer was used. The primer, undercoat, and topcoat were applied in this order, and after the primer and undercoat were applied, each was left for 5 minutes as an intermediate setting time. The coating thickness was adjusted such that the primer had a thickness of 10 μm to 15 μm, the undercoat had a thickness of 15 μm to 20 μm, and the topcoat had a thickness of 25 μm to 30 μm. After applying the paint, it was baked at a drying temperature of 70 ° C. for 30 minutes, removed from the dryer, and then cured by leaving it in a constant temperature and humidity chamber (23 ° C., 50% RH) for 72 hours, and then JIS K5600-5. According to -6, a grid pattern was cut into the coating film using a guide and a blade, and the primary adhesion was measured by peeling evaluation with an adhesive tape. Here, the case where the adhesiveness was good was evaluated as ◯, and the case where the adhesiveness was poor was evaluated as ×.

(Coating secondary adhesion)
Using a coating sample similar to the sample for evaluating the primary adhesion described above, in accordance with JIS K5600-7-2, using a wet testing machine manufactured by Suga Test Instruments Co., Ltd., a tank temperature of 50 ° C. and a relative humidity of 95%. The coating was exposed for 120 hours in a wet test atmosphere, and the coating secondary adhesion was measured by visual observation immediately after the test and by visual observation after standing for 2 hours indoors and the above primary adhesion. Here, the case where the adhesiveness was good was evaluated as ◯, and the case where the adhesiveness was poor was evaluated as ×.

(Examples 1-6, Comparative Examples 1-7)
Using a twin screw extruder (NIPPON STEEL Co., Ltd., TEX44), polyamide A, styrene resin B, and filler C having a weight ratio shown in Table 1 and Table 2 were mixed at a temperature from the initial kneading to the die. The pellet-shaped thermoplastic resin composition was obtained by setting to 270 degreeC and melt-kneading.

  The obtained thermoplastic resin composition was dried at 120 ° C. for 5 hours, and then injected into a bar-shaped test piece having a size of 10 × 100 × 6 mm using an injection molding machine with a clamping pressure of 75 t under a resin temperature of 250 ° C. Molded.

  The obtained thermoplastic resin composition was dried at 120 ° C. for 5 hours, and then injection-molded into a flat test piece having a size of about 120 × 120 × 1 mm under the condition of a resin temperature of 250 ° C.

  Various evaluation was implemented using the obtained bar-shaped test piece and a flat test piece. The results are shown in Tables 1 and 2.

  The ratio of polyamide A to styrenic resin B is remarkably inferior in primary paint adhesion and secondary paint adhesion at 79:21, and the flexural modulus and heat resistance are not sufficient at 21:79. Further, even with the filler E subjected to the hydrophobic surface treatment, the heat resistance is insufficient when the addition amount is 3 parts by weight, and the appearance of the molded product is inferior when the addition amount is 30 parts by weight.

Claims (4)

A polyamide resin 21-79 parts by weight, 100 parts by weight of base resin comprising one or more styrene-based resin 21 to 79 parts by weight, a selected from the group consisting of unsaturated carboxylic acid-modified ABS resin and polystyrene, and vinyl silazane And a thermoplastic resin composition containing 5 to 25 parts by weight of wollastonite that has been subjected to a hydrophobized surface treatment with one or more hydrophobizing agents selected from the group consisting of hexamethyldisilazane .   The thermoplastic resin composition according to claim 1, wherein the wollastonite subjected to the hydrophobizing surface treatment is acicular wollastonite having an acicular shape.   The thermoplastic resin composition according to claim 1 or 2, wherein the wollastonite subjected to the hydrophobized surface treatment has an average fiber diameter of 20 µm or less. The molded object formed by shape | molding the thermoplastic resin composition in any one of Claims 1-3 .