Thermoplastic resin compositions, thermoplastic resin molded products, and painted parts

Abstract

To provide a thermoplastic resin composition which is excellent in heat resistance, impact resistance and fluidity and gives a thermoplastic resin molded article excellent in coatability and durability.SOLUTION: The thermoplastic resin composition contains: 10-50 pts.mass of a rubber-containing graft copolymer (A) obtained by graft-polymerizing a vinyl cyanide monomer and an aromatic vinyl monomer in the presence of a rubbery polymer (a1); 5-90 pts.mass of a vinyl cyanide-maleimide copolymer (B) obtained by copolymerizing 5-30 mass% of a vinyl cyanide monomer (b1), 20-60 mass% of a maleimide monomer (b2), and 10-75 mass% of another vinyl monomer (b3); and 0-45 pts.mass of a vinyl cyanide-aromatic vinyl copolymer (C) obtained by copolymerizing a vinyl cyanide monomer and an aromatic vinyl monomer. The content of a maleimide monomer unit in the thermoplastic resin composition is 10-45 pts.mass based on 100 pts.mass of the components (A)-(C).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a thermoplastic resin composition that is excellent in heat resistance, impact resistance and fluidity as moldability and can provide a molded product excellent in paintability and durability, and a thermoplastic resin using the thermoplastic resin composition resin molded article. The present invention also relates to a thermoplastic resin painted part obtained by painting the molded article. Background Art

[0002] Rubber-reinforced styrene resins represented by ABS resins are used in a wide range of fields as office-related equipment, information and communication equipment, electronic and electrical equipment, household electrical appliances, interior and exterior parts of automobiles, exterior parts such as two-wheeled vehicles, interior parts of railway vehicles, building materials, and the like because of their excellent impact resistance, mechanical strength and chemical resistance.

[0003] In particular, for vehicle applications, improvement in heat resistance and weight reduction are required, and application of ABS resins (specific gravity: 1.07) is expected because they have a lower specific gravity than polycarbonate resins (specific gravity: 1.14 to 1.17). Furthermore, for vehicle spoilers, high heat resistance (90°C or higher), excellent paintability, and high durability (fatigue properties) have also become important.

[0004] Conventionally, thermoplastic resin compositions excellent in heat resistance and paintability have been proposed in Patent Documents 1 and 2. Prior Art Documents Patent Documents

[0005] Patent Document 1 Japanese Unexamined Patent Publication No. 2012-36384 Patent Document 2 International Publication No. WO 2018 / 116850 Summary of the Invention Problems to be Solved by the Invention

[0006] Patent Document 1 discloses a maleimide-based heat-resistant and paint-resistant thermoplastic resin composition. However, the thermoplastic resin composition in Patent Document 1 has problems such as insufficient paintability (coating) in areas subjected to stress, such as the surface of molded products; gas generation during molding; and insufficient durability. Furthermore, Patent Document 2 discloses a heat-resistant and paint-resistant thermoplastic resin composition containing two or more copolymers. However, this thermoplastic resin composition in Patent Document 2 also has problems such as insufficient paintability (coating) in areas subjected to stress, such as the surface of molded products; insufficient heat resistance; and insufficient durability.

[0007] The present invention aims to improve upon the problems of the prior art described above and provide a thermoplastic resin composition that is excellent in heat resistance, impact resistance, and fluidity, and furthermore, the paintability and durability of the resulting thermoplastic resin molded product are excellent. [Means for solving the problem]

[0008] The inventors of the present invention conducted extensive research to solve the above problems and found that a thermoplastic resin composition containing a specific rubber-containing graft copolymer (A), a vinyl cyanide-maleimide copolymer (B), and a vinyl cyanide-aromatic vinyl copolymer (C) in predetermined proportions, wherein the content of maleimide monomer units in the total of these copolymers is within a predetermined range, can solve the above problems, and thus completed the present invention. In other words, the present invention facilitates the following:

[0009] [1] 10 to 50 parts by mass of a rubber-containing graft copolymer (A) obtained by graft polymerizing a vinyl monomer mixture (a2) containing a vinyl cyanide monomer and an aromatic vinyl monomer in the presence of a rubbery polymer (a1), A vinyl cyanide-maleimide copolymer (B) is obtained by copolymerizing 5 to 30% by mass of a vinyl cyanide monomer (b1), 20 to 60% by mass of a maleimide monomer (b2), and 10 to 75% by mass of another vinyl monomer (b3) copolymerizable with these (however, the total of (b1), (b2), and (b3) is 100% by mass), and 5 to 90 parts by mass of the copolymer. A vinyl cyanide-aromatic vinyl copolymer (C) obtained by copolymerizing a vinyl monomer mixture (c1) containing a vinyl cyanide monomer and an aromatic vinyl monomer, and 0 to 45 parts by mass of the vinyl cyanide-aromatic vinyl copolymer (C) and A thermoplastic resin composition comprising a total of 100 parts by mass of the following: A thermoplastic resin composition in which the content of maleimide monomer units is 10 to 45 parts by mass relative to 100 parts by mass of the total of rubber-containing graft copolymer (A), vinyl cyanide-maleimide copolymer (B), and vinyl cyanide-aromatic vinyl copolymer (C).

[0010] [2] The thermoplastic resin composition according to [1], further comprising 0.1 to 15 parts by mass of an olefin resin (D) per 100 parts by mass of the rubber-containing graft copolymer (A), a vinyl cyanide-maleimide copolymer (B), and a vinyl cyanide-aromatic vinyl copolymer (C).

[0011] [3] The thermoplastic resin composition according to [1] or [2], further comprising 0.1 to 15 parts by mass of ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E) per 100 parts by mass of the rubber-containing graft copolymer (A), vinyl cyanide-maleimide copolymer (B), and vinyl cyanide-aromatic vinyl copolymer (C).

[0012] [4] A thermoplastic resin molded article obtained by molding any of the thermoplastic resin compositions described in [1] to [3].

[0013] [5] [4] The thermoplasticity described resin Painted parts are molded products that have been painted. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a thermoplastic resin composition that is excellent in heat resistance, impact resistance, and fluidity, and furthermore, the resulting thermoplastic resin molded product has excellent paintability and durability. Molded articles made from the thermoplastic resin composition of the present invention have excellent heat resistance, impact resistance, paintability, and durability, and can therefore be applied to a wide range of fields such as office equipment, information and communication equipment, electronic and electrical equipment, home appliances, interior and exterior parts for automobiles, exterior parts for motorcycles, interior parts for railway vehicles, and building materials, and are particularly suitable for use in vehicles. [Modes for carrying out the invention]

[0015] The embodiments of the present invention will be described in detail below, but these descriptions are merely examples (representative examples) of embodiments of the present invention, and the present invention is not limited to these contents unless it exceeds the gist of the invention.

[0016] [Thermoplastic resin composition] The thermoplastic resin composition of the present invention is 10 to 50 parts by mass of a rubber-containing graft copolymer (A) (hereinafter sometimes referred to as "component (A)") obtained by graft polymerizing a vinyl monomer mixture (a2) containing a vinyl cyanide monomer and an aromatic vinyl monomer in the presence of a rubbery polymer (a1), A vinyl cyanide-maleimide copolymer (B) (hereinafter sometimes referred to as "component (B)") obtained by copolymerizing 5 to 30% by mass of a vinyl cyanide monomer (b1), 20 to 60% by mass of a maleimide monomer (b2), and 10 to 75% by mass of another vinyl monomer (b3) copolymerizable with these (however, the total of (b1), (b2), and (b3) is 100% by mass) is 5 to 90 parts by mass, A vinyl cyanide-aromatic vinyl copolymer (C) (hereinafter sometimes referred to as "component (C)") obtained by copolymerizing a vinyl monomer mixture (c1) containing a vinyl cyanide monomer and an aromatic vinyl monomer, and 0 to 45 parts by mass of the vinyl monomer mixture (c1) and A thermoplastic resin composition comprising a total of 100 parts by mass of the following: The thermoplastic resin composition is characterized in that the content of maleimide monomer units is 10 to 45 parts by mass relative to 100 parts by mass of the total of the rubber-containing graft copolymer (A), the vinyl cyanide-maleimide copolymer (B), and the vinyl cyanide-aromatic vinyl copolymer (C).

[0017] [Rubber-containing graft copolymer (A)] The rubber-containing graft copolymer (A) is obtained by graft-polymerizing a vinyl-based monomer mixture (a2) in the presence of a rubbery polymer (a1).

[0018] <Rubbery polymer (a1)> The rubbery polymer (a1) constituting the rubber-containing graft copolymer (A) (hereinafter may be referred to as "component (a1)") is not particularly limited, and examples thereof include diene-based rubbers, acrylic rubbers, and ethylene-based rubbers. Specific examples include polybutadiene, poly(butadiene-styrene), poly(butadiene-acrylonitrile), polyisoprene, poly(butadiene-butyl acrylate), poly(butadiene-methyl acrylate), polybutyl acrylate, poly(butadiene-methyl methacrylate), poly(butadiene-ethyl acrylate), ethylene-propylene rubber, ethylene-propylene-diene rubber, poly(ethylene-isobutylene), poly(ethylene-methyl acrylate), and poly(ethylene-ethyl acrylate). These rubbery polymers may be used singly or as a mixture of two or more thereof. Among these, polybutadiene, polybutyl acrylate, and poly(butadiene-styrene) (styrene-butadiene copolymer rubber) are preferably used from the viewpoint of improving the impact resistance of the thermoplastic resin composition of the present invention.

[0019] The volume average particle diameter of the rubbery polymer (a1) is preferably 50 to 500 nm, more preferably 180 to 440 nm, and still more preferably 280 to 380 nm, from the viewpoints of impact resistance, moldability, fluidity, and appearance of the obtained thermoplastic resin composition. Here, the volume average particle diameter of the rubbery polymer (a1) is a value measured by the method described in the section of Examples provided later.

[0020] <Vinyl-based monomer mixture (a2)> The vinyl monomer mixture (a2) (hereinafter sometimes referred to as "component (a2)") is a vinyl monomer mixture containing at least an aromatic vinyl monomer and a vinyl cyanide monomer.

[0021] Examples of aromatic vinyl monomers include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, t-butylstyrene, o-ethylstyrene, o-chlorostyrene, and o,p-dichlorostyrene. These may be used individually or in combination of two or more.

[0022] Examples of vinyl cyanide monomers include acrylonitrile, methacrylonitrile, and ethanolacrylonitrile, but acrylonitrile is particularly preferred. The vinyl cyanide monomer may be used individually or in combination of two or more types.

[0023] From the viewpoint of the moldability of the resulting thermoplastic resin composition and the appearance of the molded product, the ratio of aromatic vinyl monomers to vinyl cyanide monomers in 100% by mass of vinyl monomer mixture (a2) is preferably aromatic vinyl monomer / vinyl cyanide monomer = 60-90% by mass / 10-40% by mass, more preferably 65-80% by mass / 20-35% by mass, and even more preferably 67-76% by mass / 24-33% by mass.

[0024] The vinyl monomer mixture (a2) may contain, in addition to aromatic vinyl monomers and vinyl cyanide monomers, other vinyl monomers copolymerizable with them in an amount of 0 to 30% by mass. Examples of other vinyl monomers copolymerizable with them include, but are not limited to, one or more unsaturated carboxylic acid ester monomers such as methyl (meth)acrylate, maleimide monomers such as N-methylmaleimide, N-cyclohexylmaleimide, and N-phenylmaleimide, unsaturated dicarboxylic acids such as maleic acid, unsaturated dicarboxylic acid anhydrides such as maleic anhydride, and unsaturated amides such as acrylamide. Methyl (meth)acrylate, N-phenylmaleimide, and maleic anhydride are particularly preferred. Note that "(meth)acrylic acid" refers to either or both acrylic acid and methacrylic acid.

[0025] <Ratio of rubbery polymer (a1) and vinyl monomer mixture (a2)> The rubber-containing graft copolymer (A) is preferably obtained by graft polymerizing 25 to 80% by mass of a vinyl monomer mixture (a2) in the presence of 20 to 75% by mass of a rubbery polymer (a1). However, the total amount of the rubbery polymer (a1) and the vinyl monomer mixture (a2) is 100% by mass.

[0026] When the rubbery polymer (a1) is less than 20% by mass and the vinyl monomer mixture (a2) is more than 80% by mass, the resulting thermoplastic resin composition tends to have poor impact resistance, and when the rubbery polymer (a1) is more than 75% by mass and the vinyl monomer mixture (a2) is less than 25% by mass, the impact resistance and moldability tend to decrease. The proportion of the rubbery polymer (a1) is preferably 30 to 70% by mass, more preferably 40 to 65% by mass, and the proportion of the vinyl monomer mixture (a2) is preferably 30 to 70% by mass, more preferably 35 to 60% by mass.

[0027] The rubber-containing graft copolymer (A) does not necessarily need to have the entire vinyl monomer mixture (a2) grafted; typically, a mixture obtained with an ungrafted copolymer is used. This mixture is essentially a composition, but in the present invention, it is included in the rubber-containing graft copolymer (A).

[0028] <Graft rate> There are no restrictions on the grafting ratio of the rubber-containing graft copolymer (A), but from the viewpoint of impact resistance, it is preferably 10 to 150% by mass, more preferably 15 to 100% by mass, and even more preferably 20 to 60% by mass. The grafting rate of the rubber-containing graft copolymer (A) is measured by the method described in the Examples section below.

[0029] <Molecular weight of ungrafted copolymer> The composition of the non-grafted copolymer in the rubber-containing graft copolymer (A) falls within the range of the monomer component blending ratio. The mass-average molecular weight (Mw) of the ungrafted copolymer is preferably 20,000 to 400,000, more preferably 30,000 to 200,000, and even more preferably 40,000 to 100,000. The molecular weight distribution (Mw / Mn) is preferably 1.5 to 4.0, more preferably 1.7 to 3.6, and even more preferably 1.8 to 3.2. When the mass-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) are within the above ranges, the resulting thermoplastic resin composition tends to have better fluidity, impact resistance, and paintability. Here, the mass-average molecular weight and molecular weight distribution of the ungrafted copolymer can be measured as polystyrene-converted values ​​using GPC. The details are described in the Examples section below.

[0030] <Graft polymerization method> There are no particular restrictions on the method of graft polymerization of the rubber-containing graft copolymer (A), and the rubber-containing graft copolymer (A) can be produced by any known method such as emulsion polymerization, suspension polymerization, continuous bulk polymerization, or continuous solution polymerization. The rubber-containing graft copolymer (A) is preferably produced by emulsion polymerization or bulk polymerization. From the viewpoint of being able to easily adjust the emulsifier content and water content in the rubber-containing graft copolymer (A), it is most preferable that the rubber-containing graft copolymer (A) be produced by emulsion polymerization.

[0031] Depending on the purpose, the rubber-containing graft copolymer (A) may be a blend of multiple rubber-containing graft copolymers that have been manufactured separately, such as those with different rubber particle sizes or different compositions.

[0032] <Content of rubber-containing graft copolymer (A)> In the thermoplastic resin composition of the present invention, the content of component (A) in a total of 100 parts by mass of components (A) to (C) is 10 to 50 parts by mass, preferably 20 to 40 parts by mass, more preferably 25 to 35 parts by mass, and even more preferably 26 to 34 parts by mass. If the content of component (A) is above the lower limit, impact resistance and paintability are good, and if it is below the upper limit, moldability and heat resistance are good. Furthermore, the content of the rubbery polymer (a1) in 100% by mass of the thermoplastic resin composition of the present invention is preferably 10 to 30% by mass, more preferably 12 to 28% by mass, and even more preferably 15 to 25% by mass. If the content of the rubbery polymer (a1) is above the lower limit, the impact resistance will be good, and if it is below the upper limit, the moldability and gloss will be good.

[0033] [Vinyl cyanide-maleimide copolymer (B)] The vinyl cyanide-maleimide copolymer (B) is a vinyl cyanide-maleimide copolymer obtained by copolymerizing 5 to 30% by mass of a vinyl cyanide monomer (b1) (hereinafter sometimes referred to as "component (b1)"), 20 to 60% by mass of a maleimide monomer (b2) (hereinafter sometimes referred to as "component (b2)"), and 10 to 75% by mass of another vinyl monomer (b3) (hereinafter sometimes referred to as "component (b3)") that can be copolymerized with these (however, the total of components (b1), (b2), and (b3) is 100% by mass).

[0034] Examples of vinyl cyanide monomers (b1) include acrylonitrile, methacrylonitrile, and ethanolacrylonitrile, but acrylonitrile is particularly preferred. The vinyl cyanide monomer may be used alone or as a mixture of two or more.

[0035] Examples of maleimide monomers (b2) include N-methylmaleimide, N-cyclohexylmaleimide, and N-phenylmaleimide, among which N-cyclohexylmaleimide and N-phenylmaleimide are preferred, and N-phenylmaleimide is particularly preferred. Maleimide monomers may be used individually or in combination of two or more.

[0036] Other vinyl monomers (b3) copolymerizable with components (b1) and (b2) include, but are not limited to, one or more aromatic vinyl monomers, unsaturated carboxylic acid ester monomers such as methyl (meth)acrylate, unsaturated dicarboxylic acids such as maleic acid, unsaturated dicarboxylic acid anhydrides such as maleic anhydride, or unsaturated amides such as acrylamide. Among these, aromatic vinyl monomers are preferred.

[0037] Examples of aromatic vinyl monomers include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, t-butylstyrene, o-ethylstyrene, o-chlorostyrene, and o,p-dichlorostyrene. These may be used individually or in combination of two or more.

[0038] In the production of the vinyl cyanide-maleimide copolymer (B), the proportion of each monomer in 100% by mass of the raw material vinyl monomer mixture is, from the viewpoint of heat resistance, paintability, and durability of the resulting thermoplastic resin composition, 5 to 30% by mass of vinyl cyanide monomer (b1), 20 to 60% by mass of maleimide monomer (b2), and 10 to 75% by mass of other vinyl monomers copolymerizable with these (b3) (however, the total of components (b1), (b2), and (b3) is 100% by mass), preferably 6 to 28% by mass of vinyl cyanide monomer (b1), 25 to 58% by mass of maleimide monomer (b2), and other vinyl monomers copolymerizable with these (b3 ) is 14-69% by mass, more preferably 7-25% by mass of a vinyl cyanide monomer (b1), 30-57% by mass of a maleimide monomer (b2), and 18-63% by mass of other vinyl monomers copolymerizable with these (b3), even more preferably 8-22% by mass of a vinyl cyanide monomer (b1), 40-55% by mass of a maleimide monomer (b2), and 23-52% by mass of other vinyl monomers copolymerizable with these (b3), and most preferably 9-19% by mass of a vinyl cyanide monomer (b1), 41-53% by mass of a maleimide monomer (b2), and 28-50% by mass of other vinyl monomers copolymerizable with these (b3).

[0039] The mass-average molecular weight (Mw) of the vinyl cyanide-maleimide copolymer (B) is preferably 50,000 to 300,000, and more preferably 80,000 to 200,000. Here, the mass-average molecular weight of the vinyl cyanide-maleimide copolymer (B) can be measured as a polystyrene equivalent value by GPC. The details are described in the Examples section below.

[0040] The vinyl cyanide-maleimide copolymer (B) may be used alone, or two or more types with different monomer compositions and molecular weights may be mixed and used.

[0041] In the thermoplastic resin composition of the present invention, the content of component (B) in 100 parts by mass of the total of components (A) to (C) is 5 to 90 parts by mass, preferably 20 to 70 parts by mass, more preferably 40 to 60 parts by mass, and even more preferably 42 to 58 parts by mass. If the content of component (B) is above the lower limit, it exhibits excellent heat resistance, paintability, and durability, and if it is below the upper limit, it exhibits excellent fluidity and impact resistance.

[0042] [Vinyl cyanide-aromatic vinyl copolymer (C)] The vinyl cyanide-aromatic vinyl copolymer (C) is a copolymer obtained by copolymerizing a vinyl monomer mixture containing a vinyl cyanide monomer and an aromatic vinyl monomer.

[0043] Examples of vinyl cyanide monomers include acrylonitrile, methacrylonitrile, and ethanolacrylonitrile, but acrylonitrile is particularly preferred. The vinyl cyanide monomer may be used alone or as a mixture of two or more.

[0044] Examples of aromatic vinyl monomers include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, t-butylstyrene, o-ethylstyrene, o-chlorostyrene, and o,p-dichlorostyrene. These may be used individually or in combination of two or more.

[0045] From the viewpoint of the moldability and paintability of the resulting thermoplastic resin composition, the ratio of vinyl cyanide monomers to aromatic vinyl monomers in 100% by mass of the vinyl monomer mixture (c1) is preferably vinyl cyanide monomer / aromatic vinyl monomer = 20-40% by mass / 60-80% by mass, more preferably 22-38% by mass / 62-78% by mass, even more preferably 24-35% by mass / 65-76% by mass, and most preferably 25-29% by mass / 71-75% by mass.

[0046] The vinyl monomer mixture (c1) may contain, in addition to the vinyl cyanide monomer and the aromatic vinyl monomer, other vinyl monomer units copolymerizable with them in an amount of 0 to 30% by mass. Examples of other vinyl monomers copolymerizable with them include, but are not limited to, one or more unsaturated carboxylic acid ester monomers such as methyl (meth)acrylate, maleimide monomers such as N-methylmaleimide, N-cyclohexylmaleimide, and N-phenylmaleimide, unsaturated dicarboxylic acids such as maleic acid, unsaturated dicarboxylic acid anhydrides such as maleic anhydride, or unsaturated amides such as acrylamide. Methyl (meth)acrylate, N-phenylmaleimide, and maleic anhydride are particularly preferred.

[0047] The mass-average molecular weight (Mw) of the vinyl cyanide-aromatic vinyl copolymer (C) is preferably 50,000 to 300,000, more preferably 65,000 to 200,000, and even more preferably 80,000 to 150,000. The molecular weight distribution (Mw / Mn) is preferably 1.3 to 2.8, more preferably 1.8 to 2.6, and even more preferably 1.7 to 2.4. Here, the mass-average molecular weight and molecular weight distribution of the vinyl cyanide-aromatic vinyl copolymer (C) can be measured as polystyrene equivalent values ​​using GPC. The details are described in the Examples section below.

[0048] The vinyl cyanide-aromatic vinyl copolymer (C) may be used alone, or two or more types with different monomer compositions and molecular weights may be mixed and used.

[0049] In the thermoplastic resin composition of the present invention, the content of component (C) in a total of 100 parts by mass of components (A) to (C) is 0 to 45 parts by mass, preferably 10 to 40 parts by mass, more preferably 15 to 25 parts by mass, and even more preferably 16 to 24 parts by mass. Component (C) is used as necessary to adjust fluidity, heat resistance, and impact resistance. If the content of component (C) is above the lower limit, fluidity and heat resistance can be adjusted, and if it is below the upper limit, heat resistance and impact resistance can be adjusted.

[0050] [Method of polymerization of component (B) and component (C)] The polymerization method for vinyl cyanide-maleimide copolymer (B) and vinyl cyanide-aromatic vinyl copolymer (C) is not particularly limited and can be produced by any known method such as emulsion polymerization, suspension polymerization, continuous bulk polymerization, or continuous solution polymerization. In order to improve paintability and durability and to suppress gas during molding in the present invention, it is preferable to produce them by suspension polymerization, continuous bulk polymerization, or continuous solution polymerization. The reason for this is as follows. Since the combined amount of components (B) and (C) accounts for 50 to 90 parts by mass of the total 100 parts by mass of components (A), the manufacturing methods for components (B) and (C) have a significant impact on the overall manufacturing process of the thermoplastic resin composition. Component (A) needs to adopt a graft structure through emulsion polymerization, but if the other components (B) and (C) are produced by emulsion polymerization, a washing process is required to suppress gas emissions, which not only leads to energy consumption for wastewater treatment in subsequent processes but also significantly increases the environmental burden. Therefore, it is preferable to manufacture components (B) and (C) by suspension polymerization, continuous bulk polymerization, or continuous solution polymerization, other than emulsion polymerization.

[0051] [Content of maleimide monomer units] The content of maleimide monomer units in the thermoplastic resin composition of the present invention is 10 to 45 parts by mass as a percentage of 100 parts by mass of the total of components (A), (B), and (C) (hereinafter, this percentage may be simply referred to as "maleimide monomer unit content"). If the maleimide monomer unit content is above the lower limit, the thermoplastic resin composition of the present invention can exhibit heat resistance and durability, and if it is below the upper limit, it can exhibit fluidity and impact resistance. The maleimide monomer unit content of the thermoplastic resin composition of the present invention is preferably 13 to 30 parts by mass, more preferably 16 to 28 parts by mass, even more preferably 18 to 26 parts by mass, and particularly preferably 20 to 24 parts by mass.

[0052] Here, maleimide monomer units refer to constituent units contained in the copolymer that originate from the maleimide monomers used as raw materials for each copolymer. This includes not only the maleimide monomers (b2) in the raw material monomer mixture of component (B), but also those contained in the vinyl monomer mixture (a2) of the rubber-containing graft copolymer (A) and the vinyl monomer mixture (c1) of the vinyl cyanide-aromatic vinyl copolymer (C), and which are included in the thermoplastic resin composition as constituent units of the rubber-containing graft copolymer (A) and the vinyl cyanide-aromatic vinyl copolymer (C). Furthermore, if maleimide monomer units are included in other resin components described later, these maleimide monomer units are also totaled as maleimide monomer units in the thermoplastic resin composition.

[0053] The maleimide monomer content in a thermoplastic resin composition can be determined by measuring the nitrogen and oxygen content through elemental analysis, but it can also be calculated as the maleimide monomer content in the raw materials for manufacturing each copolymer constituting the thermoplastic resin composition. In the examples shown below, the maleimide monomer content in component (B) was measured using an elemental analyzer, and the maleimide monomer content in the thermoplastic resin composition was calculated from the proportion of component (B) that made up 100 parts by mass of components (A) to (C) combined.

[0054] [Olefin resin (D)] The thermoplastic resin composition of the present invention may also contain an olefin resin (D) (hereinafter sometimes referred to as "component (D)") in addition to the above components (A), (B), and (C). Here, examples of the olefin resin (D) include a polyolefin resin (d1) and / or a modified polyolefin resin (d2).

[0055] <Polyolefin resin (d1)> The polyolefin resin (d1) (hereinafter sometimes referred to as "component (d1)") is preferably an unmodified (co)polymer consisting of at least one structural unit derived from an α-olefin having 2 or more carbon atoms. In the present invention, component (d1) is particularly preferred to be a polyolefin resin consisting of at least one structural unit derived from an α-olefin having 2 to 10 carbon atoms.

[0056] Examples of the above-mentioned α-olefins include ethylene, propylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and 3-methylhexene-1. Of these, ethylene, propylene, butene-1, 3-methylbutene-1, and 4-methylpentene-1 are preferred, and propylene is particularly preferred.

[0057] Examples of the above component (d1) include polyethylene, polypropylene, ethylene-propylene copolymer, polybutene-1, and ethylene-butene-1 copolymer. Of these, polyethylene, polypropylene, and propylene-ethylene copolymer are preferred, and from the viewpoint of the appearance and mechanical strength of the resulting thermoplastic resin molded product, polypropylene-based resins containing 85% by mass or more of propylene units relative to the total structural units, i.e., polypropylene and ethylene-propylene copolymer, are more preferred. The above ethylene-propylene copolymer can be random copolymer, block copolymer, etc., but random copolymer is particularly preferred.

[0058] The above component (d1) may be crystalline or amorphous. Preferably, it has a crystallinity of 20% or more as determined by X-ray diffraction at room temperature.

[0059] Furthermore, the molecular weight of the above component (d1) is not particularly limited, but from the viewpoint of the appearance and mechanical strength of the resulting thermoplastic resin molded product, it is preferable that the melt mass flow rate (hereinafter also referred to as "MFR") conforming to JIS K7210 is preferably 0.1 to 50 g / 10 min, more preferably 0.5 to 30 g / 10 min, at a temperature of 190°C and a load of 2.16 kg, and that the molecular weight has a value corresponding to each of these values.

[0060] Commercially available products can also be used as component (d1). For example, polypropylene such as "Novatec FY6" and "Novatec FY4" (both manufactured by Nippon Polypropylene Co., Ltd.) can be suitably used.

[0061] The component (d1) contained in the thermoplastic resin composition of the present invention may be just one type or two or more types.

[0062] <Modified polyolefin resin (d2)> The modified polyolefin resin (d2) (hereinafter sometimes referred to as "d2") is an acid-modified polyolefin resin. For example, a modified product obtained by grafting a polyolefin resin with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, maleic anhydride, itaconic anhydride, or siloxane can be used, and maleic anhydride-modified polyolefin resin is particularly preferred.

[0063] The modified polyolefin resin (d2) preferably has an acid value of 20 to 70 mgKOH / g according to JIS K0070, and its melt viscosity at 160°C is preferably 1,000 to 20,000 mPa·s, and more preferably 2,000 to 12,000 mPa·s.

[0064] Commercially available products can also be used as component (d2). For example, products such as "Yumex 1001" and "Yumex 1010" (both manufactured by Sanyo Chemical Industries, Ltd.) can be suitably used.

[0065] The component (d2) contained in the thermoplastic resin composition of the present invention may be only one type or two or more types.

[0066] <Content of olefin resin (D)> When the thermoplastic resin composition of the present invention contains an olefin resin (D), the content of polyolefin resin (d1) and / or modified polyolefin resin (d2) as the olefin resin (D) is preferably 0.1 to 15 parts by mass, more preferably 0.3 to 10 parts by mass, even more preferably 0.5 to 5 parts by mass, and particularly preferably 0.8 to 3 parts by mass, based on 100 parts by mass of the total of components (A), (B), and (C). If the amount of olefin resin (D) is above the lower limit, the paintability of the molded article made from the thermoplastic resin composition of the present invention can be improved, and if it is below the upper limit, better heat resistance, durability, and appearance can be achieved.

[0067] [Ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E)] The thermoplastic resin composition of the present invention may also contain, in addition to the above components (A), (B), and (C), an ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E) (hereinafter sometimes referred to as "component (E)"). The ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E) is a copolymer obtained by copolymerizing at least ethylene, (meth)acrylic acid ester, and carbon monoxide, and may be a random copolymer or a block copolymer, but is preferably a random copolymer. It may also be obtained by further copolymerizing other monomers that can copolymerize with these. By incorporating the ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E), the occurrence of paint blotches in the resulting thermoplastic resin molded product can be further suppressed.

[0068] In the ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E), the (meth)acrylic acid ester is preferably an ester of (meth)acrylic acid with an alcohol having 1 to 8 carbon atoms, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, etc. Two or more of these may be used. Among these, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, and isobutyl (meth)acrylate are preferred.

[0069] The glass transition temperature of the ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E) is preferably -60°C to -20°C, and particularly preferably -48°C to -35°C. Furthermore, the melting point is preferably in the range of 30°C to 80°C. Being within this range results in excellent paintability and wilting properties under environmental conditions (e.g., summer and winter).

[0070] Commercially available products can also be used as component (E). For example, the product name "Elbaroy HP661" (manufactured by Mitsui DuPont Polychemicals) can be suitably used.

[0071] The component (E) contained in the thermoplastic resin composition of the present invention may be one type or two or more types.

[0072] When the thermoplastic resin composition of the present invention contains ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E), the content of ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E) is preferably 0.1 to 15 parts by mass, more preferably 0.3 to 10 parts by mass, even more preferably 0.5 to 5 parts by mass, and particularly preferably 0.8 to 3 parts by mass, based on 100 parts by mass of the total of components (A), (B), and (C). If the content of ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E) is above the lower limit, the paintability of molded articles made from the thermoplastic resin composition of the present invention can be further improved, and if it is below the upper limit, better heat resistance, durability, and appearance can be achieved.

[0073] [Content of ingredient (D) and ingredient (E)] The thermoplastic resin composition of the present invention may yield synergistic effects when components (D) and (E) are combined and blended. By combining components (D) and (E), the total amount of each component can be reduced while effectively obtaining the above effects. Specifically, the total content of component (D) and component (E) in the thermoplastic resin composition of the present invention is preferably 0.2 to 15 parts by mass, more preferably 0.6 to 10 parts by mass, even more preferably 1 to 6 parts by mass, particularly preferably 1.5 to 4 parts by mass, and most preferably 0.8 to 3 parts by mass, based on 100 parts by mass of the total of components (A), (B), and (C).

[0074] Furthermore, when using components (D) and (E) in combination, from the viewpoint of more effectively obtaining the synergistic effect of using them together, the mass ratio of component (D):component (E) = 1:0.5 to 3 is preferable, and component (D):component (E) = 1:0.8 to 1.5 is more preferable.

[0075] [Other additives] Various additives can be added to the thermoplastic resin composition of the present invention for the purpose of improving its performance as a molding resin, to the extent that it does not impair the objectives of the present invention. For example, various stabilizers may be added as needed, such as antioxidants including hindered phenols, sulfur-containing organic compounds, and phosphorus-containing organic compounds; heat stabilizers including phenols and acrylates; transesterification inhibitors such as mixtures of monostearyl acid phosphate and distearyl acid phosphate; ultraviolet absorbers such as benzotriazoles, benzophenones, and salicylates; and light stabilizers such as organonickels and hindered amines; lubricants such as metal salts of higher fatty acids and higher fatty acid amides; plasticizers such as phthalates and phosphate esters; flame retardants and flame retardant additives such as halogen-containing compounds such as polybromodiphenyl ethers, tetrabromobisphenol-A, brominated epoxy oligomers, and brominated polycarbonate oligomers, phosphorus compounds, and antimony trioxide; and carbon black, pigments, and dyes.

[0076] [Other resins] The thermoplastic resin composition of the present invention may contain one or more other resins other than the above components (A) to (E), such as fluororesins, impact modifiers, and AS resins with a mass-average molecular weight of 500,000 or more, to the extent that the objectives of the present invention are not impaired. In this case, it is preferable that the other resins are in amounts of 10 parts by mass or less per 100 parts by mass of the total of components (A) to (E) and the other resins.

[0077] [Method for producing thermoplastic resin compositions] The thermoplastic resin composition of the present invention can be manufactured by various methods, such as melt-kneading the aforementioned components (A) and (B), or components (A) to (C), or components (A) to (C) and component (D) and / or component (E), and any additional additives or other resins used as needed, using a Banbury mixer, rolls, and a single-screw or multi-screw extruder.

[0078] [Thermoplastic resin molded product] The thermoplastic resin molded article of the present invention is obtained by molding the thermoplastic resin composition of the present invention using a known molding method. Examples of molding methods include injection molding, press molding, extrusion molding, vacuum forming, and blow molding.

[0079] The thermoplastic resin molded articles of the present invention, obtained by molding the thermoplastic resin composition of the present invention, have excellent paintability, high heat resistance, and a superior appearance. They are lighter than alloy materials such as polycarbonate due to their lower specific gravity, and also exhibit excellent durability against fatigue failure caused by vibration. They can be used in electrical and electronic components, automobile parts, mechanical components, office automation equipment, housing components for home appliances, general merchandise, and building materials. In particular, they can be suitably used as a lightweight material for automobile spoilers. In particular, the thermoplastic molded product of the present invention is useful as a painted part with a painted surface due to its excellent paintability. [Examples]

[0080] To further illustrate the present invention, examples and comparative examples are given below, but these examples are not intended to limit the present invention. Unless otherwise specified, "%" here refers to mass%, and "parts" refers to parts by mass.

[0081] In the following, the volume-average particle size of the rubbery polymer (a1) was measured according to (1) below. The grafting rate of the rubber-containing graft copolymer (A) was measured according to (2) below, and the acetone-soluble content of the rubber-containing graft copolymer (A) (ungrafted copolymer) and the mass-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the vinyl cyanide-aromatic vinyl copolymer (C) were measured according to (3) below.

[0082] (1) Volume-average particle diameter The volume-average particle size in the latex of the rubbery polymer (a1) was measured at room temperature using a HONEYWELL "Microtrac UPA150" (product name). The unit is nm. It is known that there is no substantial difference between the latex particle size of the rubbery polymer (a1) and the rubber particle size of the rubbery polymer (a1) in the resin composition using it; the former corresponds to the latter.

[0083] (2) Graft rate The grafting rate of the rubber-containing graft copolymer (A) is calculated using the following formula. Graft rate (mass%) = {[(n)-(m)×L] / [(m)×L]}×100 In the above formula, n is the mass n (g) of the acetone-insoluble component obtained by separating the acetone-insoluble and acetone-soluble components by adding approximately 1 g [weighing amount: m (g)] of rubber-containing graft copolymer (A) to 20 mL of acetone, shaking it with a shaker for 2 hours at a temperature of 25°C, and then centrifuging it with a centrifuge (rotation speed: 23,000 rpm) for 60 minutes at a temperature of 5°C. L is the mass (g) of the rubbery polymer (a1) contained in the rubber-containing graft copolymer (A). The mass of this rubbery polymer (a1) can be determined by methods such as calculating it from the polymerization formulation and polymerization conversion rate, or by determining it by infrared absorption spectroscopy.

[0084] (3) Mass-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) The mass-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) were determined using GPC (GPC: Waters "GPC / V2000", column: Showa Denko K.K. "Shodex AT-G+AT-806MS") with o-dichlorobenzene (145°C) as the solvent, and measured in polystyrene equivalent. For the measurement of ungrafted copolymers, the acetone-soluble portion at the above grafting rate was added dropwise to methanol to precipitate the polymer components. The solid portion was then filtered and dried in a vacuum dryer for 24 hours before being used for GPC measurement. For the GPC analysis of component (B), component (B) was dissolved in acetone, the polymer component was precipitated in methanol, and the mixture was dried in a vacuum dryer for 24 hours before being used for GPC analysis.

[0085] (4) Content of maleimide monomer units For component (B), which was prepared in the same manner as the sample used for GPC measurement, the nitrogen (N) and oxygen (O) elements were measured using the following elemental analyzer. • Nitrogen element analysis: JM10 MICRO CORDER (manufactured by J-SCIENCE-LAB Co., Ltd.) • Oxygen element analysis: JMO12 MICRO CORDER (manufactured by J-SCIENCE-LAB Co., Ltd.) The content of maleimide monomer units in component (B) was determined from the ratio of nitrogen (N) and oxygen (O) elements present in component (B). The content of vinyl cyanide monomers was also determined from the amount of remaining nitrogen (N).

[0086] [Rubber-containing graft copolymer (A)] <Synthesis Example 1: Production of Rubber-Containing Graft Copolymer (A1)> In a nitrogen-purged reactor, 125 parts pure water, 0.5 parts glucose, 0.5 parts sodium pyrophosphate, 0.005 parts ferrous sulfate, and 60 parts (solid content) of polybutadiene (BD) latex with a volume-average particle size of 340 nm were charged as the rubbery polymer (a1). The reactor temperature was raised to 65°C while stirring. Polymerization was started when the internal temperature reached 65°C. As component (a2), 29 parts styrene (ST) and 11 parts acrylonitrile (AN), along with 0.25 parts of a chain transfer agent t-dodecyl mercaptan mixture, were continuously added over 5 hours. Simultaneously, an aqueous solution consisting of the polymerization initiator cumene hydroperoxide (0.2 parts) and potassium oleate was continuously added over 7 hours to complete the reaction. To the obtained latex, 1 part 2,2'-methylenebis(4-methyl-6-t-butylphenol) was added per 100 parts of latex solids. Subsequently, the latex was coagulated with sulfuric acid, neutralized with sodium hydroxide, washed, filtered, and dried to obtain a powdered rubber-containing graft copolymer (A1). The composition of this rubber-containing graft copolymer (A1) was AN / BD / ST = 27 / 60 / 73, with a rubber (component (a1)) content of 60% and a grafting rate of 48%. The mass-average molecular weight of the acetone-soluble portion was 58,000, and its molecular weight distribution was 3.1.

[0087] <Synthesis Example 2: Production of Rubber-Containing Graft Copolymer (A2)> In Synthesis Example 1, the reaction was carried out in the same manner except that the amount of the chain transfer agent t-dodecyl mercaptan mixture added was 0.19 parts, to obtain a powdery rubber-containing graft copolymer (A2). The mass composition ratio of this rubber-containing graft copolymer (A2) was AN / BD / ST = 27 / 60 / 73, with a rubber (component (a1)) content of 60% and a graft rate of 62%. Furthermore, the mass-average molecular weight of the acetone-soluble portion was 162,000, and the molecular weight distribution was 3.0.

[0088] [Vinyl cyanide-maleimide copolymer (B)] <Synthesis Example 3: Production of vinyl cyanide-maleimide copolymer (B1)> In a polymerization reactor equipped with a nitrogen-purged 20-liter stirring device, 11 parts acrylonitrile (AN), 46 parts N-phenylmaleimide (PMI), 43 parts styrene (ST), 30 parts methyl ethyl ketone, 0.01 parts 1,1'-azobis(cyclohexane-1-carbonitride), and 0.05 parts t-dodecyl mercaptan were continuously supplied. While maintaining a constant temperature of 110°C inside the polymerization reactor, the polymerization reaction mixture was continuously withdrawn by a gear pump located at the bottom of the polymerization reactor so that the average residence time was 2 hours. The polymerization reaction mixture was then kept in a heat exchanger maintained at 150°C for approximately 20 minutes. Subsequently, it was introduced into a twin-screw extruder with a cylinder temperature of 230°C, and volatile components were deflated under reduced pressure of 2.67 kPaabs at the first vent and 2.67 kPaabs at the second vent. During this process, 0.38 parts dicyclopentadiene was continuously added from just before the second vent. The strands extruded from the extruder were pelletized in a pelletizer to obtain a vinyl cyanide-maleimide copolymer (B1). The obtained vinyl cyanide-maleimide copolymer (B1) had a mass composition ratio of AN / PMI / ST = 11 / 46 / 43, and a mass-average molecular weight (Mw) of 147,000.

[0089] <Synthesis Example 4: Production of vinyl cyanide-maleimide copolymer (B2)> The vinyl cyanide-maleimide copolymer (B2) was obtained by the same procedure as in Synthesis Example 3, except that the proportions of acrylonitrile, N-phenylmaleimide, and styrene were changed. The obtained vinyl cyanide-maleimide copolymer (B2) had a mass composition ratio of AN / PMI / ST = 17 / 29 / 54, and a mass-average molecular weight (Mw) of 134,000.

[0090] <Synthesis Example 5: Production of vinyl cyanide-maleimide copolymer (B3)> Except for changing the proportions of acrylonitrile, N-phenylmaleimide, and styrene, the same procedure as in Synthesis Example 3 was used to obtain a vinyl cyanide-maleimide copolymer (B3). The obtained vinyl cyanide-maleimide copolymer (B3) had a mass composition ratio of AN / PMI / ST = 5 / 46 / 49, and a mass-average molecular weight (Mw) of 176,000.

[0091] <Synthesis Example 6: Production of vinyl cyanide-maleimide copolymer (B4)> Except for changing the proportions of acrylonitrile, N-phenylmaleimide, and styrene, the same procedure as in Synthesis Example 3 was used to obtain a vinyl cyanide-maleimide copolymer (B4). The obtained vinyl cyanide-maleimide copolymer (B4) had a mass composition ratio of AN / PMI / ST = 25 / 46 / 29, and a mass-average molecular weight (Mw) of 124,000.

[0092] <Synthesis Example 7: Preparation of Maleimide Copolymer (B5) for Comparative Example> A maleimide copolymer (B5) was obtained in the same manner as in Synthesis Example 3, except that acrylonitrile was not used, only N-phenylmaleimide and styrene were used, and t-dodecyl mercaptan was 0.07. The mass composition ratio of the obtained maleimide copolymer (B5) was AN / PMI / ST = 0 / 55 / 45, and the mass-average molecular weight (Mw) was 131,000.

[0093] <Commercial product: Maleimide copolymer (B6) for comparative example> "Denka IP MS-NIP (product name)" (styrene-N-phenylmaleimide-maleic anhydride copolymer) manufactured by Denki Kagaku Kogyo Co., Ltd. was used as the maleimide copolymer (B6).

[0094] <Synthesis Example 8: Preparation of vinyl cyanide-maleimide copolymer (B7) for comparative example> The vinyl cyanide-maleimide copolymer (B7) was obtained by the same procedure as in Synthesis Example 3, except that the proportions of acrylonitrile, N-phenylmaleimide, and styrene were changed. The composition ratio of the obtained copolymer (B7) was AN / PMI / ST = 35 / 46 / 29, and the mass-average molecular weight (Mw) was 103,000.

[0095] <Synthesis Example 9: Preparation of vinyl cyanide-maleimide copolymer (B8) for reference examples> A monomer mixture consisting of 10 parts acrylonitrile, 40 parts N-phenylmaleimide, and 50 parts styrene was subjected to emulsion polymerization using 3 parts potassium stearate. After aggregation by adding the mixture to a 0.3% dilute sulfuric acid aqueous solution at 90°C, it was neutralized with an aqueous sodium hydroxide solution, followed by washing, dehydration, and drying to obtain a vinyl cyanide-maleimide copolymer (B8). The resulting vinyl cyanide-maleimide copolymer (B8) had a composition ratio of AN / PMI / ST = 10 / 40 / 50, and a mass-average molecular weight (Mw) of 144,000.

[0096] [Vinyl cyanide-aromatic vinyl copolymer (C)] <Synthesis Example 10: Production of vinyl cyanide-aromatic vinyl copolymer (C1)> In a nitrogen-purged reactor, a monomer mixture consisting of 120 parts water, 0.002 parts sodium alkylbenzenesulfonate, 0.5 parts polyvinyl alcohol, 0.3 parts azoisobutylnitrile, 0.62 parts t-dodecyl mercaptan, 32 parts acrylonitrile, and 68 parts styrene was used. The mixture was heated from a starting temperature of 60°C for 5 hours while sequentially adding a portion of the styrene, and then raised to 120°C. After further reaction at 120°C for 4 hours, the polymer was removed to obtain a vinyl cyanide-aromatic vinyl copolymer (C1) with an acrylonitrile / styrene ratio of 32 / 68. The obtained vinyl cyanide-aromatic vinyl copolymer (C1) had a mass-average molecular weight (Mw) of 96,000 and a molecular weight distribution (Mw / Mn) of 2.1.

[0097] <Synthesis Example 11: Production of vinyl cyanide-aromatic vinyl copolymer (C2)> Except for using 0.5 parts of t-dodecyl mercaptan, 27 parts of acrylonitrile, and 73 parts of styrene, the same procedure as in Synthesis Example 7 was used to obtain a vinyl cyanide-aromatic vinyl copolymer (C2) with an acrylonitrile / styrene ratio of 27 / 73. The obtained vinyl cyanide-aromatic vinyl copolymer (C2) had a mass-average molecular weight (Mw) of 112,000 and a molecular weight distribution (Mw / Mn) of 2.0.

[0098] [Olefin resin (D)] <Olefin resin (d1)> The polypropylene "Novatec FY4" (product name) manufactured by Nippon Polypropylene Co., Ltd. was used. The MFR (temperature 190°C, load 2.16 kg) in accordance with JIS K7210 was 5.0 g / 10 min.

[0099] <Olefin resin (d2)> Sanyo Chemical Industries' maleic anhydride-modified polypropylene "Yumex 1010" (product name) (melt viscosity at 160°C: 6000 mPa·s, acid value according to JIS K0070: 52 mg KOH / g (catalog value)) was used.

[0100] [Ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E)] We used "Elvaloy HP661" (trade name), an ethylene-n-butyl acrylate-carbon monoxide copolymer manufactured by Mitsui DuPont Polychemicals (glass transition temperature: -42°C, melting point: 60°C (catalog value)).

[0101] [Examples 11~21,23,24, 28 , 29. Comparative Examples 1-10, 25- 38 , and reference examples 1, 2] Components (A), (B), (C), and (D), (E) shown in Tables 1-4 were mixed in the proportions (parts) shown in Tables 1-4. Furthermore, 0.2 parts of ADEKA's A-60 (product name) (tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane) and 0.5 parts of Kao Corporation's Kao Wax EB-G (product name) (ethylene-bis-stearate amide) were added and mixed. The mixture was then melt-kneaded in a twin-screw extruder with a 30mm screw diameter and vacuum vent (Ikegai Co., Ltd. "PCM30") at a cylinder temperature of 200-260°C and a vacuum of 93.325kPa, and while taking up the strands, it was pelletized using a pelletizer (Soken Co., Ltd. "SH-type pelletizer") to obtain thermoplastic resin composition (I). The maleimide monomer content of the obtained thermoplastic resin composition (I) was calculated as the maleimide monomer content in the raw materials for the production of each copolymer, and these values ​​are shown in Tables 1 to 4. The following tests were conducted using thermoplastic resin composition (I), and the results are shown in Tables 1-4.

[0102] [Preparation of evaluation test specimens and testing methods] <Preparation of test specimen (A)> For each pelletized thermoplastic resin composition (I), a 150mm x 70mm x 3mm test piece (A) was injection molded using a Toshiba Machine injection molding machine "IS-100GN" (model name). The resin temperature during injection molding was set to 260°C and 220°C, the mold temperature to 5°C, and the injection speed to 25mm / s. A test specimen in which the resin temperature during injection molding was set to 260°C will be designated as "Test Specimen (A-1)," and a test specimen in which the resin temperature during injection molding was set to 220°C will be designated as "Test Specimen (A-2)."

[0103] <Evaluation of paintability: Underarm evaluation> For test specimens (A-1) and (A-2), painting was carried out according to the following procedure, and the presence or absence of undercoating defects on their surfaces was visually observed. The paintability was then determined based on the following evaluation criteria. (1) Condition adjustment Test specimens (A-1) and (A-2) were conditioned by leaving them in a constant temperature bath adjusted to 5°C for more than 12 hours. (2) Painting The surfaces of test pieces (A-1) and (A-2) (the side without ejector pin marks) were spray-coated with a paint consisting of 80 parts acrylic resin-based paint base, 85 parts synthetic resin paint thinner, and 10 parts hardener (paint film thickness: 20-30 μm), and left at 23°C for 5 minutes. (3) Drying The painted test specimens were then dried at 80°C for 30 minutes. <Evaluation of paint defects (underarms)> ◎: No defects occurred on the surface of the test specimen (suitable for use). ○: 1-3 small defects were found on the surface of the test specimen (usable). △: 4-10 small defects were found on the surface of the test specimen (barely usable). ×: More than 11 defects were found on the surface of the test specimen (unusable).

[0104] <Preparation of test specimen (a)> Using an injection molding machine (manufactured by Shibaura Machine Co., Ltd., product name "IS55FP-1.5A"), a pellet-shaped thermoplastic resin composition (I) was injection molded under conditions of cylinder temperature 220-250°C and mold temperature 60°C to obtain a test specimen (a) measuring 80 mm in length, 10 mm in width, and 4 mm in thickness. Test specimen (a) was used to measure Charpy impact strength and load deflection temperature.

[0105] <Evaluation of impact resistance: Measurement of Charpy impact strength> For test specimen (A), a Charpy impact test (with notch) was performed at 23°C in accordance with ISO 179 standard, and the Charpy impact strength was measured. A higher value indicates superior impact resistance.

[0106] <Heat resistance evaluation: Measurement of heat deflection temperature (HDT)> For test specimen (I), the HDT was measured according to ISO 75 standard under conditions of a load of 1.80 MPa and flat width (4 mm thickness). A higher HDT indicates superior heat resistance.

[0107] <Assessment of liquidity: Measurement of melt volume rate (MVR)> For the pelletized thermoplastic resin composition (I), the MVR (cm²) of the thermoplastic resin composition (I) was measured in accordance with ISO 1133 standards, under conditions of a temperature of 220°C and a load of 98N (10kg). 3 The MVR (Mass Volume Rating) was measured (at 10 minutes). MVR is an indicator of the fluidity of thermoplastic resin compositions; the higher the MVR, the better the fluidity.

[0108] <Evaluation of molded appearance> The test specimen (A-2) was visually inspected and evaluated according to the following criteria. ○: No abnormalities (suitable for use) △: Slight flow marks or gas clouding may occur (usable). ×: Flow marks or gas clouding occur (unusable)

[0109] <Preparation of test specimen (c)> Using an injection molding machine (manufactured by Shibaura Machine Co., Ltd., product name "IS55FP-1.5A"), a pellet-shaped thermoplastic resin composition (I) was injection molded under the conditions of a cylinder temperature of 220-250°C and a mold temperature of 60°C. A test specimen (U) with a thickness of 3.2 mm, L=31.8 mm, b=20.6 mm, and L / b=1.54 was obtained in accordance with the Type III test specimen (wedge shape) of JIS K7119 "Fatigue Test Method for Planar Bending of Plastic Sheets". Test specimen (U) was used for fatigue testing.

[0110] <Vibration fatigue test> For test specimen (c), the number of cycles until failure was measured using the following testing machine and under the following test conditions. A higher number of cycles indicates superior vibration fatigue resistance. Testing machine: Toyo Seiki Seisakusho B-50 type cyclic vibration fatigue testing machine Test temperature: 80℃ Test stress: 23 MPa Test conditions: Repeat rate 1800 cycles / min, frequency 30Hz

[0111] [Table 1]

[0112] [Table 2]

[0113] [Table 3]

[0114] [Table 4]

[0115] [Result summary] Based on the above evaluation results, the example corresponds to the thermoplastic resin composition of the present invention. 11~21,23,24,28, Material 29 possesses excellent paintability, heat resistance, fluidity, impact resistance, and appearance, and furthermore, it demonstrates sufficiently excellent performance in fatigue tests. In contrast, Comparative Examples 1-4, lacking acrylonitrile in component (B), exhibited inferior paintability, particularly at 220°C where molding stress strain occurs. Furthermore, their fatigue characteristics at high temperatures tended to be inferior compared to Examples 1-4. Comparative Examples 5 and 6 show that while the paintability tends to improve when component (D) is added to components (B) that do not contain acrylonitrile, the fatigue characteristics tend to be inferior to those of Comparative Examples 1 to 4. Comparative Example 7 had a higher concentration of acrylonitrile in component (B) than the specified range of the present invention, resulting in inferior fluidity and a tendency for inferior fatigue characteristics. Comparative Examples 8, 9, and 10 had significantly lower heat resistance and, in particular, performed poorly in vibration fatigue tests under high-temperature conditions because they contained less maleimide monomer units than the specified range of the present invention. Reference examples 1 and 2 show cases where components (D) and (E) were added in excess, resulting in inferior impact resistance, heat resistance, and molded appearance.

Claims

1. 10 to 50 parts by mass of a rubber-containing graft copolymer (A) obtained by graft polymerizing a vinyl monomer mixture (a2) containing a vinyl cyanide monomer and an aromatic vinyl monomer in the presence of a rubbery polymer (a1), 5 to 90 parts by mass of a vinyl cyanide-maleimide copolymer (B) obtained by copolymerizing 5 to 28% by mass of a vinyl cyanide monomer (b1), 20 to 58% by mass of a maleimide monomer (b2), and 14 to 75% by mass of another vinyl monomer (b3) copolymerizable with these (however, the total of (b1), (b2), and (b3) is 100% by mass), A vinyl cyanide-aromatic vinyl copolymer (C) obtained by copolymerizing a vinyl monomer mixture (c1) containing a vinyl cyanide monomer and an aromatic vinyl monomer, and 0 to 45 parts by mass of the vinyl cyanide-aromatic vinyl copolymer (C) and A thermoplastic resin composition comprising a total of 100 parts by mass of the following: The rubbery polymer (a1) is one or more selected from polybutadiene, butyl polyacrylate, and poly(butadiene-styrene) (styrene-butadiene copolymer rubber), The mass-average molecular weight (Mw) of the vinyl cyanide-maleimide copolymer (B) is 80,000 to 200,000. The content of maleimide monomer units in the thermoplastic resin composition is 20 to 28 parts by mass, relative to 100 parts by mass of the total of the rubber-containing graft copolymer (A), the vinyl cyanide-maleimide copolymer (B), and the vinyl cyanide-aromatic vinyl copolymer (C), A thermoplastic resin composition that does not contain olefin resin (D) and ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E), or in which the content of olefin resin (D) or ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E) is 10 parts by mass or less per 100 parts by mass of the total of the rubber-containing graft copolymer (A), vinyl cyanide-maleimide copolymer (B), and vinyl cyanide-aromatic vinyl copolymer (C), or the total content of olefin resin (D) and ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E) is 10 parts by mass or less.

2. The thermoplastic resin composition according to claim 1, further comprising 0.1 to 5 parts by mass of an olefin resin (D) per 100 parts by mass of the total of the rubber-containing graft copolymer (A), the vinyl cyanide-maleimide copolymer (B), and the vinyl cyanide-aromatic vinyl copolymer (C).

3. The thermoplastic resin composition according to claim 1 or 2, further comprising 0.1 to 5 parts by mass of ethylene / (meth)acrylic acid ester / carbon monoxide copolymer (E) per 100 parts by mass of the total of the rubber-containing graft copolymer (A), vinyl cyanide-maleimide copolymer (B), and vinyl cyanide-aromatic vinyl copolymer (C).

4. A thermoplastic resin molded article obtained by molding a thermoplastic resin composition according to any one of claims 1 to 3.

5. A painted part obtained by applying paint to a thermoplastic resin molded product as described in claim 4.

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