Thermoplastic resin composition and molded article thereof

Abstract

To provide a thermoplastic resin composition enabling acquisition of a molded article which maintains or improves mechanical properties such as impact resistance intrinsic to thermoplastic resin, and which is excellent in appearance, and furthermore stably exhibits millimeter wave properties in a high range.SOLUTION: A thermoplastic resin composition is provided, including: 1 to 80 pts.mass of polypropylene graft polymer (E) obtained by graft-polymerizing vinyl monomer (D1) to polypropylene resin particles (C) which include 100 pts.mass of a polypropylene resin (A) and 5 to 25 pts.mass of an acid-modified olefin resin (B) and each of which has a volume average particle diameter of 50 to 850 nm; and 20 to 99 pts.mass of graft polymer (G) obtained by graft-polymerizing a vinyl monomer (D2) to ethylene-α-olefin rubber polymer (F) with ethylene unit content of 50-95 mass%, (the total of polypropylene graft polymer (E) and graft polymer (G) is 100 pts.mass).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic resin composition capable of providing a molded article that maintains or improves the inherent mechanical properties of thermoplastic resins, such as impact resistance, while also having an excellent appearance and that further stably exhibits millimeter-wave properties in a high range, and to a molded article made from the thermoplastic resin composition, as well as to a millimeter-wave radome and a millimeter-wave radar that include the molded article. [Background technology]

[0002] In recent years, there has been active development of wireless communication systems and sensors equipped with millimeter-wave radar that transmit and receive millimeter waves, and a wide range of applications have been proposed. Some of these have already been put to practical use, such as sensors that instantly detect the position and speed of moving people and objects, and imaging devices for security checks.

[0003] Millimeter-wave radar typically comprises an antenna module that transmits or receives millimeter waves, and a radome (antenna cover) that houses or protects it. Radomes are typically made of resin molded parts and come in a variety of shapes depending on the application. Some radomes are made entirely from a material that transmits radio waves easily, while others have only specific sections, corresponding to the radio wave path, made from a material that transmits radio waves easily.

[0004] Various studies have been conducted on millimeter wave transparent molding materials that constitute millimeter wave radomes, and for example, the following Patent Documents 1 and 2 have been proposed.

[0005] Patent Document 1 discloses a millimeter-wave-transmitting resin part made of a thermoplastic resin composition containing a rubber-polymer-reinforced vinyl resin having a polymer portion derived from an ethylene-α-olefin rubber with a specific ethylene unit content and a vinyl resin portion.

[0006] Patent Document 2 discloses a resin part that is placed in the path of a beam emitted by a radar device, and that is made by blending AES resin and polycarbonate resin with a polypropylene-based graft polymer (PP-g-AS). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-121334 [Patent Document 2] International Publication No. 2017 / 104714 Summary of the Invention [Problem to be solved by the invention]

[0008] As described above, various proposals have been made so far regarding millimeter wave transmissive molding materials for millimeter wave radomes, but the molding material of Patent Document 1, although having millimeter wave characteristics to some extent, is still insufficient. Patent Document 2 aims to further improve millimeter wave characteristics by blending a PP-g-AS body, but the stability of the millimeter wave characteristics is not sufficient, so there is a possibility that there will be a lot of variation and many defective products when used in a high-dimensional radar device. Defects in the radar equipment raise safety concerns, and not only does it result in wasted manufacturing energy due to defective products, but variations in radar performance could also lead to reduced safety.

[0009] An object of the present invention is to provide a thermoplastic resin composition that can provide a molded article that maintains or improves the inherent mechanical properties of a thermoplastic resin, such as impact resistance, has excellent appearance, and further stably exhibits millimeter wave characteristics in a high range, and to provide a molded article made from the thermoplastic resin composition. [Means for solving the problem]

[0010] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result have found that the above-mentioned problems can be solved by blending, in predetermined proportions, a polypropylene-based graft polymer (E) obtained by graft polymerizing a vinyl-based monomer (D1) onto polypropylene-based resin particles (C) having a specific particle size and containing a polypropylene resin (A) and an acid-modified olefin resin (B) in a predetermined ratio, and a graft polymer (G) obtained by graft polymerizing a vinyl-based monomer (D2) onto an ethylene-α-olefin-based rubber polymer (F) having an ethylene unit content of 50 to 95 mass%.

[0011] That is, the present invention is summarized as follows.

[0012] [1] A thermoplastic resin composition comprising: 1 to 80 parts by mass of a polypropylene graft polymer (E) obtained by graft polymerizing a vinyl monomer (D1) onto polypropylene resin particles (C) having a volume average particle size of 50 to 850 nm, the polypropylene graft polymer (E) comprising 100 parts by mass of a polypropylene resin (A) and 5 to 25 parts by mass of an acid-modified olefin resin (B); and 20 to 99 parts by mass of a graft polymer (G) obtained by graft polymerizing a vinyl monomer (D2) onto an ethylene-α-olefin rubber polymer (F) having an ethylene unit content of 50 to 95% by mass (provided that the total of the polypropylene graft polymer (E) and the graft polymer (G) is 100 parts by mass).

[0013] [2] The thermoplastic resin composition according to [1], wherein the graft ratio of the polypropylene-based graft polymer (E) is 10 to 70 mass %.

[0014] [3] The thermoplastic resin composition according to [1] or 2, wherein, of 100% by mass of the vinyl monomer (D1), 50 to 90% by mass is an aromatic vinyl compound and 10 to 50% by mass is a vinyl cyanide compound.

[0015] [4] The thermoplastic resin composition according to any one of [1] to [3], wherein the polypropylene graft polymer (E) is obtained by graft polymerizing 20 to 70 mass % of a vinyl monomer (D1) (wherein the total of the polypropylene resin particles (C) and the vinyl monomer (D1) is 100 mass %) in the presence of 30 to 80 mass % of polypropylene resin particles (C).

[0016] [5] The thermoplastic resin composition according to any one of [1] to [4], wherein the polypropylene-based resin particles (C) are obtained by melt-kneading the polypropylene resin (A) and the acid-modified olefin resin (B) and dispersing the resulting kneaded mixture in an aqueous medium.

[0017] [6] The thermoplastic resin composition according to any one of [1] to [5], wherein, of 100% by mass of the vinyl monomer (D2), 50 to 90% by mass is an aromatic vinyl compound and 10 to 50% by mass is a vinyl cyanide compound.

[0018] [7] The thermoplastic resin composition according to any one of [1] to [6], wherein the graft polymer (G) is a rubber-polymer-reinforced vinyl resin having a graft polymer portion derived from an ethylene-α-olefin rubber polymer (F) and a vinyl monomer (D2) and a vinyl resin portion, and the contents of the graft polymer portion and the vinyl resin portion are 10 to 90 mass% and 90 to 10 mass%, respectively, relative to 100 mass% of the total, and the graft ratio is 20 to 65%.

[0019] [8] A molded article obtained by molding the thermoplastic resin composition according to any one of [1] to [7].

[0020] [9] A millimeter wave radome including the molded article described in [8].

[0021]

[10] A millimeter wave radar equipped with a millimeter wave radome described in [9]. [Effects of the Invention]

[0022] The thermoplastic resin composition of the present invention can provide a molded article that has excellent appearance while maintaining or improving the mechanical properties such as impact resistance inherent to thermoplastic resins, and further, stably exhibits millimeter wave characteristics in a high range. According to a thermoplastic resin molded article made from the thermoplastic resin composition of the present invention, it is possible to provide a high-quality and highly reliable millimeter-wave radome and millimeter-wave radar that are excellent in mechanical properties such as impact resistance, appearance, etc., as well as in millimeter-wave properties and their stability. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, an embodiment of the present invention will be described in detail.

[0024] [Thermoplastic resin composition] The thermoplastic resin composition of the present invention comprises: 1 to 80 parts by mass of a polypropylene graft polymer (E) (hereinafter, sometimes referred to as "the polypropylene graft polymer (E) of the present invention") obtained by graft polymerizing a vinyl monomer (D1) onto polypropylene resin particles (C) having a volume average particle diameter of 50 to 850 nm, the polypropylene resin particles (C) including 100 parts by mass of a polypropylene resin (A) and 5 to 25 parts by mass of an acid-modified olefin resin (B); 20 to 99 parts by mass of a graft polymer (G) (hereinafter, sometimes referred to as "the graft polymer (G) of the present invention") obtained by graft polymerizing a vinyl monomer (D2) to an ethylene-α-olefin rubber polymer (F) having an ethylene unit content of 50 to 95% by mass, (wherein the total of the polypropylene graft polymer (E) and the graft polymer (G) is 100 parts by mass).

[0025] [Polypropylene-based graft polymer (E)] The polypropylene-based graft polymer (E) of the present invention is obtained by graft polymerizing a vinyl-based monomer (D1) onto polypropylene-based resin particles (C) containing 100 parts by mass of a polypropylene resin (A) and 5 to 25 parts by mass of an acid-modified olefin resin (B) and having a volume average particle size of 50 to 850 nm. The polypropylene-based graft polymer (E) of the present invention makes it possible to obtain a thermoplastic resin molded article having excellent impact resistance and appearance, and a thermoplastic resin composition containing the same can further stabilize and improve millimeter wave characteristics.

[0026] <Polypropylene resin (A)> The polypropylene resin (A) may be any resin containing propylene units as the main component in an amount of 50 mol % or more, preferably 80 to 100 mol %, of all constituent units. Examples of such resins include homopolymers, which are homopolymers of propylene; random copolymers obtained by copolymerizing propylene with copolymerizable components such as ethylene and α-olefins such as 1-butene; and block copolymers obtained by homopolymerizing propylene and then copolymerizing propylene with copolymerizable components such as ethylene and α-olefins such as 1-butene. Any of these may be used.

[0027] Commercially available homopolymers of polypropylene resin (A) can be used, such as Prime Polypro J105G, Prime Polypro J106G, Prime Polypro J106MG, Prime Polypro J108M, and Prime Polypro J-700GP, manufactured by Prime Polymer Co., Ltd., and Noblen FS2011DG3, Noblen WF836DG3, Noblen D101, Noblen W101, and Noblen Z101A, manufactured by Sumitomo Chemical Co., Ltd.

[0028] Commercially available random copolymers of polypropylene resin (A) can be used, such as Prime Polypro J226T, Prime Polypro J229E, Prime Polypro J-721GR, Prime Polypro J-2021GR, Prime Polypro J-2023GR, Prime Polypro J-2041GA, and Prime Polypro J-3021GR, manufactured by Prime Polymer Co., Ltd., and Noblen FL6632G, Noblen FL6737, and Noblen S131, manufactured by Sumitomo Chemical Co., Ltd.

[0029] Commercially available block copolymers of polypropylene resin (A) can be used, such as Prime Polypro BJS-MU, Prime Polypro J704LB, Prime Polypro J704UG, Prime Polypro U705UG, Prime Polypro J715M, Prime Polypro J707G, Prime Polypro J707EG, Prime Polypro J830HV, Prime Polypro J708UG, and Prime Polypro J709QG, manufactured by Prime Polymer Co., Ltd., and Noblen AD571, Noblen AW564, and Noblen AZ564, manufactured by Sumitomo Chemical Co., Ltd.

[0030] The degree of polymerization (molecular weight) of the polypropylene resin (A) is not particularly limited, but the melt mass flow rate (hereinafter also referred to as MFR) measured in accordance with JIS K7210 at a measurement temperature of 230°C and a load of 50 N is preferably 40 to 70 g / 10 min, more preferably 45 to 65 g / 10 min. When the MFR is within this range, a more stable emulsified state can be achieved during the production of the polypropylene-based resin particles (C). When the MFR is outside this range, emulsion formation tends to be insufficient, and the time for which the emulsified state remains stable tends to be shortened.

[0031] Such polypropylene resin (A) may be used alone or in combination with two or more different types having different physical properties, types of copolymerization components, copolymerization compositions, etc.

[0032] The polypropylene resin (A) to be used can be selected depending on the purpose. However, when producing the polypropylene-based graft polymer (E) of the present invention, it is preferable to use a random copolymer, particularly a propylene-ethylene random copolymer or a propylene-1-butene random copolymer, from the viewpoint of emulsion stability.

[0033] <Acid-modified olefin resin (B)> The acid-modified polyolefin resin (B) is an acid-modified polyolefin resin that is a polymer or copolymer of one or more olefins, such as ethylene, propylene, 1-butene, 2-butene, isobutene, 1-pentene, 2-pentene, cyclopentene, 1-hexene, 2-hexene, cyclohexene, 1-heptene, 2-heptene, cycloheptene, 1-octene, 2-octene, cyclooctene, vinylcyclopentene, vinylcyclohexene, vinylcycloheptene, vinylcyclooctene, etc. As the polyolefin resin, only one of these may be used, or two or more may be used, but among these, it is particularly preferable to use polypropylene.

[0034] The modifying group introduced by acid modification of the polyolefin resin is preferably a sulfo group, a carboxyl group, a phosphate group, a hydroxyl group, a thiol group, etc., and is particularly preferably a carboxyl group. The acid-modified olefin resin (B) having a carboxyl group introduced as an acid-modifying group can be obtained by modifying a polyolefin resin with a saturated or unsaturated carboxylic acid having a carboxyl group and a compound containing an acid anhydride group thereof.

[0035] Examples of saturated or unsaturated carboxylic acids having a carboxyl group include formic acid, acetic acid, propionic acid, acrylic acid, methacrylic acid, oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, phthalic acid, and terephthalic acid. Examples of acid anhydride group-containing compounds include maleic anhydride, acetic anhydride, propionic anhydride, succinic anhydride, and phthalic anhydride. These may be used alone or in combination of two or more.

[0036] The acid value of the acid-modified polyolefin resin (B) is preferably 1 to 60 mgKOH / g, more preferably 5 to 50 mgKOH / g. When the acid value is 1 mgKOH / g or more, the stability in the emulsified state becomes good, and when it is 60 mgKOH / g or less, excellent compatibility is easily obtained. From the same viewpoint, for example, in the case of a maleic anhydride-modified polyolefin resin, the graft amount of maleic anhydride is preferably 1 to 20 mass%, more preferably 1 to 10 mass%. When the graft amount of maleic anhydride is 1 mass% or more, the stability in the emulsified state becomes good, and when it is 20 mass% or less, excellent compatibility is easily obtained.

[0037] Commercially available products can be used as the acid-modified polyolefin resin (B). Examples of commercially available products of the acid-modified polyolefin resin (B) include UMEX 1001 manufactured by Sanyo Chemical Industries, Ltd., and HIWAX NP0555A and HIWAX NP50605A manufactured by Mitsui Chemicals, Inc.

[0038] The acid-modified polyolefin resin (B) may be used alone or in combination with two or more different types of acid-modified groups introduced, amounts introduced, acid values, types of polyolefin resins, etc.

[0039] The acid-modified polyolefin resin (B) is used in an amount of 5 to 25 parts by mass per 100 parts by mass of the polypropylene resin (A), and this blending amount is preferably 7 to 22 parts by mass. By including 5 to 25 parts by mass of the acid-modified polyolefin resin (B) per 100 parts by mass of the polypropylene resin (A), the emulsified state is stabilized, thereby making it possible to reduce the influence on the properties when blended into a thermoplastic resin composition.

[0040] <Polypropylene resin particles (C)> The polypropylene-based resin particles (C) according to the present invention are prepared by emulsifying and dispersing a polypropylene-based resin composition containing 100 parts by mass of polypropylene resin (A) and 5 to 25 parts by mass, preferably 7 to 22 parts by mass of acid-modified olefin resin (B) in an aqueous medium, with the polypropylene-based resin composition having a volume average particle diameter within a specific range.

[0041] The preparation method of polypropylene-based resin particles (C) is not particularly limited.The preparation method of polypropylene-based resin particles (C) can be exemplified by: melt-kneading polypropylene resin (A) and acid-modified olefin resin (B) with known melt-kneading means (kneader, Banbury mixer, multi-screw extruder, etc.), dispersing by applying mechanical shearing force, and adding to an aqueous medium containing an emulsifier; dissolving polypropylene resin (A) and acid-modified olefin resin (B) in a hydrocarbon solvent (pentane, hexane, heptane, benzene, toluene, xylene, etc.) together with an emulsifier, adding this to an aqueous medium to emulsify, then stirring thoroughly, and then distilling off the hydrocarbon solvent; etc.

[0042] A preferred method for producing polypropylene-based resin particles (C) is to melt-knead the polypropylene resin (A) and the acid-modified olefin resin (B) at a temperature of about 180 to 240°C, apply mechanical shear force to disperse the mixture, and add the mixture to an aqueous medium containing an emulsifier, because production without using organic solvents can avoid the odor of residual solvents and the health and environmental impacts of volatile substances, and further, no special equipment is required for ventilation of organic solvent components during production.

[0043] Examples of the emulsifier include known emulsifiers, such as long-chain alkyl carboxylates, alkyl sulfosuccinates, and alkylbenzene sulfonates.

[0044] The amount of emulsifier added is preferably 1 to 15 parts by mass per 100 parts by mass of the polypropylene resin (A) when an anionic emulsifier such as potassium oleate is used as the emulsifier, because this can suppress thermal discoloration of the resulting polypropylene resin particles (C) and makes it easy to control the particle size of the polypropylene resin particles (C). It is preferable to premix the emulsifier with the polypropylene resin (A) and the acid-modified olefin resin (B) prior to melt-kneading, from the viewpoint of improving the dispersibility of the polypropylene-based resin particles (C) and the stability of the emulsion.

[0045] During melt-kneading, an alkali such as potassium hydroxide or sodium hydroxide is added as an aqueous solution. Adding an aqueous alkali solution makes it easier to control the volume average particle size of the resulting polypropylene resin particles (C). The alkali is preferably added as an aqueous solution with a concentration of about 5 to 20% by mass, and the amount added varies depending on other conditions and the desired volume average particle size, but is preferably about 1 to 10 parts by mass per 100 parts by mass of the polypropylene resin (A).

[0046] The polypropylene resin (A) and the acid-modified olefin resin (B) are melt-kneaded and dispersed by applying mechanical shear force to obtain a kneaded mixture, which is then cooled to 60 to 120°C and then added to an aqueous medium for emulsification. Water is usually used as the aqueous medium. From the viewpoint of dispersibility, the temperature of the aqueous medium when the kneaded mixture is added is preferably 80 to 90°C.

[0047] The solids concentration (polypropylene resin particle (C) concentration) of the aqueous dispersion of polypropylene resin particles (C) obtained in this manner is preferably about 20 to 60 mass % from the viewpoints of ease of handling during the subsequent graft polymerization reaction, productivity, long-term emulsion stability, etc.

[0048] In the present invention, the volume average particle diameter of the polypropylene resin particles (C) is 50 to 850 nm, preferably 150 to 750 nm, and more preferably 250 to 650 nm, from the viewpoints of excellent emulsion stability, dispersibility in thermoplastic resins, and physical properties of the resulting molded products. Here, the volume average particle size of the polypropylene resin particles (C) is a value measured by the method described in the Examples section below.

[0049] Methods for controlling the volume average particle diameter of the polypropylene resin particles (C) include adjusting the type or amount of emulsifier, addition of alkali during melt-kneading, shear force applied during kneading, temperature conditions, etc.

[0050] <Vinyl Monomer (D1)> Examples of the vinyl monomer (D1) include aromatic vinyl compounds, vinyl cyanide compounds, (meth)acrylic acid ester compounds, maleimide compounds, unsaturated acid anhydrides, carboxyl group-containing unsaturated compounds, amino group-containing unsaturated compounds, amide group-containing unsaturated compounds, hydroxyl group-containing unsaturated compounds, oxazoline group-containing unsaturated compounds, etc. These compounds may be used alone or in combination of two or more.

[0051] The vinyl monomer (D1) preferably contains an aromatic vinyl compound, and more preferably is a monomer mixture further containing a vinyl cyanide compound.

[0052] Examples of aromatic vinyl compounds include styrene, α-methylstyrene, o-, m-, or p-methylstyrene, vinylxylene, pt-butylstyrene, and ethylstyrene. From the viewpoint of the impact resistance and appearance of the resulting molded article, styrene and α-methylstyrene are preferred. The aromatic vinyl compounds may be used alone or in combination of two or more.

[0053] Examples of the vinyl cyanide compound include acrylonitrile, methacrylonitrile, etc. One type of vinyl cyanide compound may be used alone, or two or more types may be used in combination.

[0054] The content of the aromatic vinyl compound is preferably 50 to 90 mass%, more preferably 60 to 85 mass%, and even more preferably 70 to 80 mass%, based on 100 mass% of the vinyl monomer (D1). When the content of the aromatic vinyl compound is within the above range, the color development property and impact resistance of the obtained molded article are further improved. The content of the vinyl cyanide compound is preferably 10 to 50 mass%, more preferably 15 to 40 mass%, and even more preferably 20 to 30 mass%, relative to 100 mass% of the vinyl monomer (D1). When the content of the vinyl cyanide compound is within the above range, the impact resistance and appearance of the molded article are further improved.

[0055] In addition to the aromatic vinyl compound and the vinyl cyanide compound, the vinyl monomer (D1) may contain other monomers copolymerizable therewith in an amount of, for example, 30% by mass or less based on 100% by mass of the vinyl monomer (D1), as long as the effect of the present invention is not impaired.

[0056] Examples of the other monomers include (meth)acrylic acid ester compounds (methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, etc.), maleimide compounds (N-cyclohexylmaleimide, N-phenylmaleimide, etc.), etc. One type of the other monomers may be used alone, or two or more types may be used in combination.

[0057] <Polypropylene-based graft polymer (E)> The polypropylene graft polymer (E) of the present invention can be obtained by graft polymerizing a vinyl monomer (D1) in the presence of polypropylene resin particles (C).

[0058] The polypropylene-based graft polymer (E) of the present invention is preferably obtained by graft polymerizing 20 to 70 mass % of a vinyl-based monomer (D1) (where the total of the polypropylene-based resin particles (C) and the vinyl-based monomer (D1) is 100 mass %) in the presence of 30 to 80 mass % of polypropylene-based resin particles (C) because the resulting molded article has excellent impact resistance and appearance.

[0059] The graft ratio of the polypropylene graft polymer (E) is preferably 10 to 70% by mass, more preferably 15 to 60% by mass, and even more preferably 20 to 50% by mass, in view of excellent impact resistance and appearance of the resulting molded article. The graft ratio is a value measured by the method described in the Examples section below.

[0060] The graft polymerization method of the vinyl monomer (D1) onto the polypropylene resin particles (C) may be a known polymerization method (emulsion polymerization, solution polymerization, suspension polymerization, bulk polymerization, or a combination thereof, etc.) As the graft polymerization method, emulsion polymerization is particularly preferred because the resulting molded article has better impact resistance and appearance.

[0061] An example of a method for producing the polypropylene graft polymer (E) by emulsion polymerization is a method in which an organic peroxide is mixed with a vinyl monomer (D1), and the vinyl monomer (D1) is then continuously added to an aqueous dispersion of polypropylene resin particles (C) to carry out graft polymerization at about 70 to 95°C. The organic peroxide is preferably used as a redox initiator in which an organic peroxide, a transition metal, and a reducing agent are combined. During graft polymerization, a chain transfer agent, an emulsifier, etc. may be used depending on the situation.

[0062] As the redox initiator, a combination of an organic peroxide and ferrous sulfate-chelating agent-reducing agent is preferred, since it does not require high temperature polymerization reaction conditions, it avoids deterioration of the polypropylene resin particles (C), and it can avoid a decrease in the impact resistance of the resulting molded article. Examples of organic peroxides include cumene hydroperoxide, diisopropylbenzene hydroperoxide, and t-butyl hydroperoxide, and the amount of the organic peroxide added is preferably about 0.5 to 4 parts by mass per 100 parts by mass of the vinyl monomer (D1). The redox initiator is more preferably one consisting of cumene hydroperoxide, ferrous sulfate, sodium pyrophosphate, and dextrose and / or lactose.

[0063] Examples of chain transfer agents include mercaptans (octyl mercaptan, n- or t-dodecyl mercaptan, n-hexadecyl mercaptan, n- or t-tetradecyl mercaptan, etc.), allyl compounds (allylsulfonic acid, methallylsulfonic acid, sodium salts thereof, etc.), α-methylstyrene dimer, etc. Mercaptans are preferred because they allow for easy molecular weight adjustment. One type of chain transfer agent may be used alone, or two or more types may be used in combination. The chain transfer agent may be added all at once, in portions, or continuously.

[0064] The amount of the chain transfer agent added is preferably 2.0 parts by mass or less based on 100 parts by mass of the vinyl monomer (D1).

[0065] Examples of the emulsifier include anionic surfactants, nonionic surfactants, and amphoteric surfactants. Examples of the anionic surfactant include sulfate esters of higher alcohols, alkylbenzene sulfonates, fatty acid sulfonates, phosphoric acid salts, fatty acid salts, and amino acid derivative salts. Examples of nonionic surfactants include ordinary polyethylene glycol alkyl esters, alkyl ethers, alkyl phenyl ethers, and the like. Examples of amphoteric surfactants include those having a carboxylate, sulfate, sulfonate, phosphate, or the like in the anion moiety and an amine salt, quaternary ammonium salt, or the like in the cation moiety.

[0066] The amount of the emulsifier added is preferably 10 parts by mass or less based on 100 parts by mass of the vinyl monomer (D1).

[0067] The polypropylene graft polymer (E) obtained by emulsion polymerization is in a state of being dispersed in an aqueous medium. As a method for recovering the polypropylene graft polymer (E) from an aqueous dispersion containing the polypropylene graft polymer (E), for example, a precipitation method can be mentioned in which a precipitating agent is added to the aqueous dispersion, the mixture is heated and stirred, the precipitating agent is separated, and the precipitated polypropylene graft polymer (E) is washed with water, dehydrated, and dried. Examples of precipitating agents include aqueous solutions of sulfuric acid, acetic acid, calcium chloride, magnesium sulfate, etc. One precipitating agent may be used alone, or two or more precipitating agents may be used in combination.

[0068] If necessary, an antioxidant may be added to the aqueous dispersion containing the polypropylene-based graft polymer (E).

[0069] The thermoplastic resin composition of the present invention may contain only one type of polypropylene-based graft polymer (E), or may contain two or more types that differ in physical properties, types of copolymerization components, copolymerization compositions, etc.

[0070] [Graft polymer (G)] The graft polymer (G) of the present invention is a graft polymer obtained by graft polymerizing a vinyl monomer (D2) onto an ethylene-α-olefin rubber polymer (F) having an ethylene unit content of 50 to 95% by mass, and is a copolymer rubber containing structural units derived from ethylene and structural units derived from an α-olefin, and has a graft polymer portion derived from the ethylene-α-olefin rubber polymer (F) having an ethylene unit content (content ratio of structural units derived from ethylene) of 50 to 95% by mass and the vinyl monomer (D2), and a vinyl resin portion derived from the vinyl monomer (D2).

[0071] <Ethylene-α-olefin rubber polymer (F)> The ethylene-α-olefin rubber polymer (F) is a copolymer rubber consisting of structural units derived from ethylene and structural units derived from α-olefin, or a copolymer rubber containing structural units derived from a non-conjugated diene in addition to these structural units.

[0072] The amount of ethylene units constituting the ethylene-α-olefin rubber polymer (F) is 50 to 95 mass%, preferably 30 to 85 mass%, more preferably 40 to 80 mass%, and even more preferably 45 to 75 mass%, from the viewpoints of the mechanical properties, moldability, and appearance of the obtained molded article in the thermoplastic resin composition of the present invention.

[0073] Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, and 1-eicosene. These α-olefins can be used alone or in combination of two or more. The carbon number of the α-olefin is preferably 3 to 20, more preferably 3 to 12, and even more preferably 3 to 8, from the viewpoints of the mechanical properties and moldability of the thermoplastic resin composition of the present invention and the appearance of the molded article obtained.

[0074] Examples of the non-conjugated dienes include alkenylnorbornenes, cyclic dienes, aliphatic dienes, etc. These non-conjugated dienes can be used alone or in combination of two or more.

[0075] When the ethylene-α-olefin rubber polymer (F) is an ethylene-α-olefin-non-conjugated diene copolymer rubber, the upper limit of the content of structural units derived from non-conjugated dienes is preferably 15% by mass, more preferably 10% by mass, and even more preferably 5% by mass, when the total amount of structural units constituting the ethylene-α-olefin rubber polymer (F) is taken as 100% by mass.

[0076] From the viewpoint of millimeter wave transmittance, the ethylene-α-olefin rubber polymer (F) is preferably a copolymer consisting of ethylene units and α-olefin units having 3 to 8 carbon atoms, more preferably an ethylene-propylene copolymer, an ethylene-1-butene copolymer, or an ethylene-1-octene copolymer, and particularly preferably an ethylene-propylene copolymer.

[0077] The ethylene-α-olefin rubber polymer (F) can also be used after being treated with the acid-modified olefin resin (B) described above, in the same manner as the polypropylene resin particles (C) in the polypropylene graft polymer (E). In this case, the reaction can be carried out in the same manner as for the polypropylene resin particles (C) described above, using typically 5 to 25 parts by mass, preferably 7 to 22 parts by mass, of the acid-modified olefin resin (B) per 100 parts by mass of the ethylene-α-olefin rubber polymer (F).

[0078] <Vinyl Monomer (D2)> Examples of the vinyl monomer (D2) include aromatic vinyl compounds, vinyl cyanide compounds, (meth)acrylic acid ester compounds, maleimide compounds, unsaturated acid anhydrides, carboxyl group-containing unsaturated compounds, amino group-containing unsaturated compounds, amide group-containing unsaturated compounds, hydroxyl group-containing unsaturated compounds, oxazoline group-containing unsaturated compounds, etc. These compounds may be used alone or in combination of two or more.

[0079] The vinyl monomer (D2) preferably contains an aromatic vinyl compound, and more preferably is a monomer mixture further containing a vinyl cyanide compound.

[0080] Examples of aromatic vinyl compounds include styrene, α-methylstyrene, o-, m-, or p-methylstyrene, vinylxylene, pt-butylstyrene, and ethylstyrene. From the viewpoint of the impact resistance and appearance of the resulting molded article, styrene and α-methylstyrene are preferred. The aromatic vinyl compounds may be used alone or in combination of two or more.

[0081] Examples of the vinyl cyanide compound include acrylonitrile, methacrylonitrile, etc. One type of vinyl cyanide compound may be used alone, or two or more types may be used in combination.

[0082] The content of the aromatic vinyl compound is preferably 50 to 90 mass%, more preferably 60 to 85 mass%, and even more preferably 70 to 80 mass%, based on 100 mass% of the vinyl monomer (D2). When the content of the aromatic vinyl compound is within the above range, the color development property and impact resistance of the obtained molded article are further improved.

[0083] The content of the vinyl cyanide compound is preferably 10 to 50 mass%, more preferably 15 to 40 mass%, and even more preferably 20 to 30 mass%, based on 100 mass% of the vinyl monomer (D2). When the content of the vinyl cyanide compound is within the above range, the impact resistance and appearance of the molded article are further improved.

[0084] In addition to the aromatic vinyl compound and the vinyl cyanide compound, the vinyl monomer (D2) may contain other monomers copolymerizable therewith in an amount of, for example, 30% by mass or less based on 100% by mass of the vinyl monomer (D2), as long as the effects of the present invention are not impaired.

[0085] Examples of the other monomers include (meth)acrylic acid ester compounds (methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, etc.), maleimide compounds (N-cyclohexylmaleimide, N-phenylmaleimide, etc.), etc. One type of the other monomers may be used alone, or two or more types may be used in combination.

[0086] <Graft polymer (G)> The graft polymer (G) of the present invention can be obtained by graft polymerizing a vinyl monomer (D2) in the presence of an ethylene-α-olefin rubber polymer (F). The graft polymer (G) thus obtained has a graft polymer portion derived from the ethylene-α-olefin rubber polymer (F) and the vinyl monomer (D2), and a vinyl resin portion derived from the vinyl monomer (D2). From the viewpoints of mechanical properties, moldability, and the appearance of the resulting molded article, the contents of the rubber polymer portion and the vinyl resin portion constituting the graft polymer (G) are preferably 10 to 90% by mass and 90 to 10% by mass, more preferably 20 to 80% by mass and 80 to 20% by mass, and even more preferably 25 to 75% by mass and 75 to 25% by mass, respectively, when the total of these is taken as 100% by mass.

[0087] The graft rate of the graft polymer (G) is preferably 20% by mass or more, more preferably 30% by mass or more, and particularly preferably 35 to 65% by mass, from the viewpoints of mechanical properties, moldability, and the appearance of the resulting molded article. Here, the graft ratio of the graft polymer (G) is a value measured by the method described in the Examples section below.

[0088] The graft polymerization method of the vinyl monomer (D2) onto the ethylene-α-olefin rubber polymer (F) may be any known polymerization method (emulsion polymerization, solution polymerization, suspension polymerization, bulk polymerization, or a combination thereof).

[0089] The thermoplastic resin composition of the present invention may contain only one type of graft polymer (G), or may contain two or more types that differ in physical properties, types of copolymerization components, copolymerization compositions, etc.

[0090] [Thermoplastic resin] The thermoplastic resin composition of the present invention is a thermoplastic resin composition containing the polypropylene-based graft polymer (E) of the present invention and the graft polymer (G). The thermoplastic resin composition of the present invention may contain a thermoplastic resin other than the polypropylene-based graft polymer (E) and the graft polymer (G) of the present invention.

[0091] Examples of thermoplastic resins that the thermoplastic resin composition of the present invention may contain in addition to the polypropylene-based graft polymer (E) and graft polymer (G) of the present invention include one or more of polyvinyl chloride, polystyrene, ABS resin, ASA resin, SAS resin derived from silicone rubber, AS copolymer, acrylonitrile-styrene-methyl methacrylate copolymer, styrene-acrylonitrile-N-phenylmaleimide copolymer, α-methylstyrene-acrylonitrile copolymer, polymethyl methacrylate, methyl methacrylate-styrene copolymer, methyl methacrylate-N-phenylmaleimide copolymer, polycarbonate, polyamide, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyolefins such as polypropylene and polyethylene, and polyphenylene ether-polystyrene composites.

[0092] [Content of each ingredient] The contents of the polypropylene-based graft polymer (E) and the graft polymer (G) in the thermoplastic resin composition of the present invention are, per 100 parts by mass in total, 1 to 80 parts by mass of the polypropylene-based graft polymer (E) and 20 to 99 parts by mass of the graft polymer (G), preferably 10 to 80 parts by mass of the polypropylene-based graft polymer (E) and 20 to 90 parts by mass of the graft polymer (G), more preferably 20 to 75 parts by mass of the polypropylene-based graft polymer (E) and 25 to 80 parts by mass of the graft polymer (G), and particularly preferably 35 to 75 parts by mass of the polypropylene-based graft polymer (E) and 25 to 65 parts by mass of the graft polymer (G). This blending ratio can be selected depending on the purpose and application. By setting the content ratio of the polypropylene graft polymer (E) and the graft polymer (G) within the above range, the thermoplastic resin composition of the present invention can effectively exhibit the effects and stability of millimeter wave characteristics while suppressing or improving deterioration in mechanical properties such as impact resistance and appearance.

[0093] When the thermoplastic resin composition of the present invention contains a thermoplastic resin other than the polypropylene-based graft polymer (E) and graft polymer (G) of the present invention, the content thereof is preferably 0 to 200 parts by mass, particularly 10 to 190 parts by mass, and especially 20 to 150 parts by mass, per 100 parts by mass of the total of the polypropylene-based graft polymer (E) and the graft polymer (G). The amount of thermoplastic resin to be blended can be selected depending on the purpose and application, but by setting the amount within the above range, the thermoplastic resin composition of the present invention can suppress or improve deterioration in mechanical properties such as impact resistance and appearance, and can also effectively exhibit the effects and stability of millimeter wave properties.

[0094] Furthermore, the total proportion of polypropylene resin components in 100% by mass of all resin components in the thermoplastic resin composition of the present invention (the total proportion of polypropylene resin (A) in the polypropylene graft polymer (E) and propylene resins contained in the thermoplastic resin composition as other thermoplastic resins) is preferably 5 to 40% by mass, particularly 10 to 35% by mass, and even more preferably 13 to 32% by mass, from the viewpoint of efficiently and stably exhibiting the effects of mechanical properties such as impact resistance, appearance, and millimeter wave properties.

[0095] [Additives] The thermoplastic resin composition of the present invention may contain additives as needed. Examples of the additives include one or more of colorants such as pigments and dyes, fillers (carbon black, silica, titanium oxide, etc.), flame retardants, stabilizers, reinforcing agents, processing aids, heat resistance agents, antioxidants, weather resistance agents, release agents, plasticizers, and antistatic agents.

[0096] [Molded product] The molded article of the present invention is obtained by molding the thermoplastic resin composition of the present invention, and is excellent in impact resistance and appearance, as well as in millimeter wave characteristics and stability thereof.

[0097] The quality of the molded appearance of a molded article made from the thermoplastic resin composition of the present invention can be evaluated by the method described in the Examples section below. The molded appearance, such as color development (L* value when colored with carbon black) and surface gloss, evaluated here is also related to the dispersion state of the polypropylene resin component (uncolored portion) observed in a transmission electron microscope image (10,000x magnification) obtained by the method described in the Examples section below. That is, the molded appearance of a molded article made from the thermoplastic resin composition of the present invention can be evaluated by the method described in the Examples section below. 2 Total area per ΣS (μm 2 The larger this value, the more the polypropylene resin component is finely dispersed in the matrix, and the better the appearance. 2 Total perimeter ΣL (μm) / total area ΣS (μm 2 From the viewpoint of the appearance of the molded product, the ratio is preferably 0.08 or more, and more preferably 0.1 or more.

[0098] Examples of methods for molding the thermoplastic resin composition of the present invention include injection molding, injection compression molding, extrusion, blow molding, vacuum molding, pressure molding, calendar molding, inflation molding, etc. Among these, injection molding and injection compression molding are preferred because they are suitable for mass production and can produce molded products with high dimensional accuracy.

[0099] The molded article of the present invention obtained by molding the thermoplastic resin composition of the present invention has excellent impact resistance and appearance, and can stably exhibit millimeter wave characteristics. Therefore, the molded article is suitable for millimeter wave radar parts, radomes for millimeter wave radars, and millimeter wave radars that require these characteristics, and can also be used as vehicle parts. Furthermore, the molded article can be suitably used for ship components and home appliance parts such as communication equipment, office automation equipment, mobile devices, toys, vacuum cleaners, televisions, and air conditioners.

[0100] [Millimeter-wave radome and millimeter-wave radar] Since a molded article made from the thermoplastic resin composition of the present invention has excellent millimeter-wave characteristics and stability, it can be used as a millimeter-wave-transmitting resin part in a millimeter-wave radome. Specifically, a millimeter-wave radome can be constructed using only the thermoplastic resin molded article of the present invention. Furthermore, a millimeter-wave radome can be constructed by using the thermoplastic resin molded article of the present invention as a millimeter-wave-transmitting resin part and combining it with other resin parts.

[0101] A millimeter-wave radome using the thermoplastic resin molded product of the present invention can provide a millimeter-wave radar that is excellent in millimeter-wave characteristics and stability, and has high accuracy and reliability. [Example]

[0102] The present invention will be explained in more detail below by way of examples and comparative examples, but the present invention is not limited to the following examples in any way as long as the gist of the invention is not exceeded. In the following description, "parts" means "parts by mass" and "%" means "% by mass".

[0103] [Measurement, evaluation and operation methods] The various measurements, evaluations and procedures therefor in the following Examples and Comparative Examples are as follows:

[0104] <Measurement of average particle size> The volume average particle size (MV) measured using a Microtrac (Nanotrac 150 manufactured by Nikkiso Co., Ltd.) and pure water as the measurement solvent was taken as the average particle size.

[0105] <Calculation of graft ratio-1> 1 g of polypropylene graft polymer (E) was added to 80 mL of acetone and heated to reflux at 65 to 70°C for 3 hours. The resulting acetone suspension was centrifuged at 14,000 rpm for 30 minutes using a centrifuge (Hitachi Koki Co., Ltd., "CR21E") to separate the precipitate (acetone-insoluble component) and the acetone solution (acetone-soluble component). The precipitate (acetone-insoluble component) was then dried and its mass (Ya (g)) was measured, and the graft ratio was calculated using the following formula (1). In the formula (1), Ya is the mass (g) of the acetone-insoluble component of the polypropylene-based graft polymer (E), Xa is the total mass (g) of the polypropylene-based graft polymer (E) used to determine Ya, and the particle mass fraction is the content of the polypropylene-based resin particles (C) in the polypropylene-based graft polymer (E) converted to solid content. Graft rate (%) = {(Ya-Xa×particle mass fraction) / Xa×particle mass fraction}×100...(1)

[0106] <Calculation of graft ratio-2> 1 g of graft polymer (G) was added to 80 mL of acetone and heated to reflux at 65 to 70°C for 3 hours. The resulting acetone suspension was centrifuged at 14,000 rpm for 30 minutes using a centrifuge (Hitachi Koki Co., Ltd., "CR21E") to separate the precipitate (acetone-insoluble component) and the acetone solution (acetone-soluble component). The precipitate (acetone-insoluble component) was then dried and its mass (Yb (g)) was measured, and the graft ratio was calculated using the following formula (2). In formula (2), Yb is the mass (g) of the acetone-insoluble component of the graft polymer (G), Xb is the total mass (g) of the ethylene-α-olefin rubber polymer (F) used to determine Yb, and the mass fraction of rubber is the content of the ethylene-α-olefin rubber polymer (F) in the graft polymer (G) converted to solid content. Graft rate (%) = {(Yb-Xb × rubber mass fraction) / Xb × rubber mass fraction} × 100 (2)

[0107] <Melt mixing> The resin components were mixed according to the resin component formulation shown in Table 1, and melt-kneaded in a 30 mm diameter vacuum vented twin-screw extruder ("PCM30" manufactured by Ikegai Corporation) at a cylinder temperature of 200 to 260°C and a vacuum of 93.325 kPa to obtain a transparent thermoplastic resin composition. After melt-kneading, the mixture was pelletized using a pelletizer ("SH-type pelletizer" manufactured by Soken Co., Ltd.).

[0108] <Melt Volume Rate (MVR) Measurement> The MVR of the thermoplastic resin composition obtained by melt-kneading was measured at 220°C and 10 kgf in accordance with ISO 1133. The MVR is an index of the fluidity of the thermoplastic resin composition.

[0109] <Injection molding 1 (physical property evaluation)> The pellets of the thermoplastic resin composition obtained by melt kneading were molded into a molded article measuring 80 mm in length, 10 mm in width, and 4 mm in thickness using an injection molding machine (Toshiba Machine Co., Ltd., "IS55FP-1.5A") at a cylinder temperature of 200 to 270°C and a mold temperature of 60°C, to obtain molded article 1 for physical property measurement.

[0110] <Injection molding 2 (appearance evaluation)> 100 parts of the thermoplastic resin composition pellets obtained by melt kneading and 0.8 parts of carbon black were mixed using a Henschel mixer, and this mixture was fed into an extruder heated to 240°C and kneaded to obtain black pellets. These black pellets were then molded into a plate measuring 100 mm in length, 100 mm in width, and 1 mm in thickness using an injection molding machine (Toshiba Machine Co., Ltd., "IS55FP-1.5A") at a cylinder temperature of 200 to 270°C and a mold temperature of 60°C, to obtain molded product 2 for appearance evaluation.

[0111] <Injection molding 3 (dielectric property evaluation)> The pellets of the thermoplastic resin composition obtained by melt kneading were molded using an injection molding machine (Toshiba Machine Co., Ltd., "IS55FP-1.5A") at a cylinder temperature of 200 to 270°C and a mold temperature of 60°C to form a molded product measuring 80 mm in length, 10 mm in width, and 4 mm in thickness.The flow end on the opposite side of the gate was cut to 10 mm x 10 mm, and then processed to a thickness of 0.244 mm using a surface grinder to produce molded product 3 for dielectric property measurement.

[0112] <Injection molding 4 (tensile property evaluation)> The pellets of the thermoplastic resin composition obtained by melt kneading were molded using an injection molding machine (Toshiba Machine Co., Ltd., "IS55FP-1.5A") at a cylinder temperature of 200 to 270°C and a mold temperature of 60°C to form a dumbbell-shaped tensile test piece with a total length of 170 mm, a parallel portion length of 80 mm, a central parallel portion width of 10 mm, and a thickness of 4 mm, which was used as molded piece 4 for measuring tensile properties.

[0113] <Density measurement> The density of molded product 1 obtained by injection molding 1 was measured in accordance with ISO1183.

[0114] <Charpy impact strength measurement> The molded article 1 obtained by injection molding 1 was subjected to a Charpy impact test (with a notch) at 23°C in accordance with ISO179 standard to measure the Charpy impact strength.

[0115] <Measurement of tensile breaking strain> For the molded product 4 obtained by injection molding 4, the tensile breaking strain (%) of a dumbbell-shaped tensile test piece was measured in accordance with ISO527 at a chuck distance of 115 mm and a tension speed of 50 mm / min.

[0116] <Measurement of flexural modulus> For molded product 1 obtained by injection molding 1, a test piece (width 10 mm, thickness 4 mm, length 80 mm) was subjected to a three-point bending test in accordance with ISO 178 at a support distance of 64 mm and a bending speed of 2 mm / min to measure the flexural modulus.

[0117] <Appearance evaluation of molded products> (visual evaluation) The surface layer and the area around the gate of molded product 2 obtained by injection molding 2 were visually evaluated, and the evaluation results are shown below. No problem: No defects in the molded appearance, no practical problems. Peeling: Peeling has occurred on the surface of the molded product, making it unusable. White blur / haze: The surface of the molded product has white blur or haze, making it unusable.

[0118] Furthermore, the following measurements were carried out on this molded product 2.

[0119] (Evaluation of color development) The lightness L* of the molded article 2 was measured by the SCE method using a spectrophotometer ("CM-3500d" manufactured by Konica Minolta Optips Co., Ltd.). The measured L* was designated as "L*(ma)." The lower the L*, the blacker the color, and the better the color development. "Lightness L*" refers to the lightness value (L*) among the color values ​​in the L*a*b* color system adopted in JIS Z8729. The "SCE method" refers to a method of measuring color using a spectrophotometer conforming to JIS Z8722, eliminating specularly reflected light using a light trap.

[0120] (surface gloss measurement) For molded product 2, the reflectance (%) of the molded product surface was measured at an incident angle of 60° and a reflection angle of 60° in accordance with JIS K7105 using a "Digital Variable Gloss Meter UGV-5D" manufactured by Suga Test Instruments Co., Ltd. The higher the reflectance, the better the surface appearance.

[0121] (TEM image analysis) A thin film having a thickness of 100 nm was prepared from a sample cut out from molded article 2 for appearance evaluation, and this thin film was stained with ruthenium tetroxide (RuO4) to prepare a thin film for observation with a transmission electron microscope (TEM). This thin film for TEM observation was observed at 10,000 magnification using a transmission electron microscope JEM-1400plus (JEOL Ltd.), and a TEM image was obtained. This TEM image was subjected to binary image processing of the stained portion (styrene-containing component) and the unstained portion (polypropylene resin component), and the total area ΣS (μm 2 ) was measured. In addition, after binarizing the obtained TEM image, the length of the phase interface of the unstained component (polypropylene resin component) was measured, and the sum of these values ​​was taken as the total perimeter ΣL (μm) of the unstained portion (polypropylene resin component). From these values, the unstained area of ​​1 μm 2 Total perimeter ΣL (μm) / total area ΣS (μm 2 ) ratio was calculated.

[0122] <Measurement of relative permittivity and dielectric loss tangent (tanδ)> The relative permittivity and dielectric loss tangent of molded product 3 obtained by injection molding 3 were measured at a frequency of approximately 77 GHz using an Agilent Technologies device according to the cut-off cylindrical waveguide method (JIS R1660-1). Since the frequency is determined by the thickness and relative permittivity of the test piece, the thickness of molded product 3 used as the test piece was set to 0.244 mm for the measurement. Ten test pieces were prepared and each was measured. The minimum and maximum values ​​of the ten measured values ​​and the average value of each measurement result were recorded for the relative permittivity. The average value was recorded for the dielectric loss tangent.

[0123] <Polypropylene resin (A)> The following was used as polypropylene resin (A). Prime Polymer Co., Ltd.: Propylene random copolymer "Prime Polypro J229E" MFR: 50g / 10min (230℃ / 50N load)

[0124] <Acid-modified polyolefin resin (B)> The following was used as the acid-modified olefin polymer (B-1). Mitsui Chemicals: Maleic anhydride modified polypropylene "Hiwax NP0555A" Maleic anhydride graft amount: 3% by mass Acid value: 45mgKOH / g The following was used as the acid-modified olefin polymer (B-2). Mitsui Chemicals: Maleic anhydride modified polypropylene "Hiwax 2203A" Mass average molecular weight: 2,700 Acid value: 30mgKOH / g

[0125] <Production of Polypropylene Resin Particles (C)> 100 parts of polypropylene resin (A), 20 parts of acid-modified olefin polymer (B-1), and 5 parts of potassium oleate as an anionic emulsifier were mixed. This mixture was fed at 4 kg / h from the hopper of a twin-screw extruder (Ikegai Corporation, "PCM30", L / D = 40). While continuously feeding an aqueous solution of 0.63 parts potassium hydroxide and 3.87 parts ion-exchanged water from a feed port provided at the vent of the twin-screw extruder, the mixture was heated to 220 °C, melt-kneaded, and extruded. The melt-kneaded mixture was continuously fed to a cooling device attached to the tip of the twin-screw extruder and cooled to 90 °C. The solid discharged from the tip of the twin-screw extruder was then poured into 80 °C warm water, continuously dispersed, and diluted to a solids concentration of approximately 40%, yielding an aqueous dispersion of polypropylene-based resin particles (C). The volume average particle diameter of the polypropylene-based resin particles (C) was 500 nm.

[0126] <Production of Polypropylene Graft Polymer (E-1)> A stainless steel polymerization vessel equipped with a stirrer was charged with 60 parts of an aqueous dispersion of polypropylene-based resin particles (C) in terms of solids content, and ion-exchanged water was added to adjust the solids concentration to 30%, followed by the addition of 0.008 parts of ferrous sulfate, 0.35 parts of sodium pyrophosphate, and 0.35 parts of fructose, and the temperature was raised to 80° C. 30 parts of styrene, 10 parts of acrylonitrile, and 0.62 parts of cumene hydroperoxide were continuously added for 150 minutes, and emulsion polymerization was carried out while maintaining the polymerization temperature at 80° C., yielding an aqueous dispersion containing a polypropylene-based graft polymer with a volume average particle diameter of 510 nm. An antioxidant was added to the aqueous dispersion containing the polypropylene-based graft polymer, and the solid content was precipitated with sulfuric acid. After washing, dehydration and drying, a powdery polypropylene-based graft polymer was obtained. The graft ratio of this polypropylene-based graft polymer was measured and found to be 30%. This powdery polypropylene graft polymer did not contain any organic solvent and therefore had no solvent odor.

[0127] <Production of Polypropylene Graft Polymer (e-1)> In the presence of 100 parts of toluene solvent and 30 parts of polypropylene resin (A), 49 parts of styrene and 21 parts of acrylonitrile were solution polymerized to obtain a polypropylene-based graft polymer (e-1). The graft ratio of this graft copolymer (e-1) was 38.2%. The particle size of the polypropylene-based resin portion of this graft polymer (e-1) could not be determined.

[0128] <Production of Graft Polymer (G-1)> A graft polymer (G-1) using ethylene-α-olefin rubber was obtained by solution polymerization of styrene and acrylonitrile in the presence of ethylene-propylene copolymer rubber (56% ethylene units and 44% propylene units) in toluene. This graft polymer (G-1) is a rubber-reinforced resin containing 45% grafted polymer (ethylene-propylene copolymer rubber) with styrene and acrylonitrile grafted onto it, and 53.4% ​​ungrafted acrylonitrile-styrene copolymer resin. The graft ratio of the graft polymer (G-1) was 50%, and the content of the ethylene-propylene copolymer rubber was 30%, the content of acrylonitrile units was 21%, and the content of styrene units was 49%.

[0129] <Production of Graft Polymer (G-2)> 100 parts of an ethylene-propylene-non-conjugated diene copolymer (Mitsui Chemicals: EPT3012P, ethylene unit content 73% and containing 4% of 5-ethylidene-2-norbornene as a non-conjugated diene component), 20 parts of an acid-modified olefin polymer (B-2), and 5 parts of a tallow fatty acid potassium salt (a mixture of potassium oleate, potassium stearate, and potassium palmitate) as an anionic emulsifier were mixed.

[0130] This mixture was supplied from the hopper of a twin-screw extruder (manufactured by Ikegai Corporation, "PCM30", L / D = 40) at 4 kg / Hr. While continuously supplying an aqueous solution prepared by mixing 0.5 part of potassium hydroxide and 2.4 parts of ion-exchanged water from the supply port provided in the vent section of this twin-screw extruder, it was heated to 220°C, melt-kneaded, and extruded. The melt-kneaded product was continuously supplied to a cooling device attached to the tip of the twin-screw extruder and cooled to 90°C. Then, the solid discharged from the tip of the twin-screw extruder was put into warm water at 80°C and continuously dispersed, diluted to a solid content concentration of around 40% by mass, to obtain an olefin resin aqueous dispersion.

[0131] Next, this olefin resin aqueous dispersion (60 parts as the solid content of an ethylene·propylene·non-conjugated diene copolymer) was put into a stainless steel polymerization tank equipped with a stirrer. Ion-exchanged water was added to the olefin resin aqueous dispersion so that the solid content concentration became 30%. 0.006 part of ferrous sulfate, 0.3 part of sodium pyrophosphate, 0.35 part of fructose, and 1.0 part of potassium tallow fatty acid (a mixture of potassium oleate, potassium stearate, and potassium palmitate) were charged, and the temperature was set to 80°C. Here, 30 parts of styrene, 10 parts of acrylonitrile, and 1.0 part of cumene hydroperoxide were continuously added over 150 minutes, maintaining the polymerization temperature at 80°C to conduct emulsion polymerization, to obtain an aqueous dispersion containing a graft polymer (G-2). An antioxidant was added to the aqueous dispersion containing the graft polymer (G-2), and precipitation of the solid content was carried out with sulfuric acid. Through the processes of dehydration, washing, and drying, a powdery graft polymer (G-2) was obtained. This graft polymer (G-2) is a rubber-reinforced resin containing 84% of a graft polymer part in which styrene and acrylonitrile are graft-polymerized onto an ethylene·propylene copolymer rubber and 15.2% of an ungrafted acrylonitrile·styrene copolymer resin. The graft ratio in the graft polymer (G-2) is 40%, the content of the ethylene·propylene copolymer rubber part is 60%, the content of acrylonitrile units is 10%, and the content of styrene units is 30%.

[0132] <Production of ABS Resin> 50 parts of polybutadiene (gel content 94%, average particle diameter 290 nm), 35 parts of styrene, 15 parts of acrylonitrile (5% in the monomer component), 0.1 part of t-dodecyl mercaptan, 1.0 part of sodium rosinate, 0.05 part of potassium hydroxide, and 160 parts of pure water were charged into a reactor, heated to 60 °C and impregnated for 60 minutes. Then, 0.3 part of t-hexyl peroxypivalate was added, and the temperature was raised to 75 °C and polymerization was carried out for 2 hours. An antioxidant was added to the obtained latex, which was then poured into an aqueous calcium chloride solution for coagulation, followed by washing, dehydration, and drying to obtain an ABS resin.

[0133] <Production of AS copolymer> 120 parts of ion-exchanged water, 0.1 part of polyvinyl alcohol, 0.3 part of azobisisobutyronitrile, 25 parts of acrylonitrile, 75 parts of styrene, and 0.35 part of t-dodecyl mercaptan were charged into a nitrogen-substituted stainless steel polymerization tank equipped with a stirrer, and reacted at an initial temperature of 60 °C for 5 hours. After raising the temperature to 120 °C and reacting for 4 hours, the content was taken out, washed, and dried to obtain a powdery AS copolymer.

[0134] <Aromatic polycarbonate resin (PC)> As the aromatic polycarbonate resin, "Iupilon S-2000F" (viscosity average molecular weight (Mv): 22,000) manufactured by Mitsubishi Engineering-Plastics Corporation was used.

[0135] [Example 1] The polypropylene-based graft polymer (E-1), AS copolymer, and graft polymer (G-1) were mixed in the compounding amounts shown in Table 1, and melt-kneaded at a cylinder temperature of 200 - 260 °C and a vacuum of 93.325 kPa using a twin-screw extruder with a 30 mmφ vacuum vent ("PCM30" manufactured by Ikegai Corporation) to obtain a transparent thermoplastic resin composition. The content of the polypropylene resin component in the obtained thermoplastic resin composition was 15% by mass. After melt-kneading, pelletization was carried out using a pelletizer ("SH type pelletizer" manufactured by Soken). The shape of the obtained pellets was a cylindrical shape with a diameter of 3 mm and a length of 3 mm, and the weight per pellet was 21 mg.

[0136] [Examples 2 to 5] Pellets of thermoplastic resin compositions were obtained in the same manner as in Example 1, except that the resin component formulations were as shown in Table 1. The content of the polypropylene resin component in the obtained thermoplastic resin compositions was 30% by mass in Examples 2 and 4, and 15% by mass in Examples 3 and 5.

[0137] [Comparative Examples 1 and 2] Pellets of thermoplastic resin compositions were obtained in the same manner as in Example 1, except that polypropylene resin (A) was used instead of the polypropylene-based graft polymer and the resin component formulation was as shown in Table 1. The content of the polypropylene resin component in the obtained thermoplastic resin composition was 15 mass% in Comparative Example 1 and 30 mass% in Comparative Example 2.

[0138] Comparative Example 3 Pellets of a thermoplastic resin composition were obtained in the same manner as in Example 1, except that polypropylene-based graft polymer (e-1) was used instead of polypropylene-based graft polymer (E-1) and the resin component composition shown in Table 1 was used.

[0139] Comparative Example 4 Pellets of a thermoplastic resin composition were obtained in the same manner as in Example 1, except that the polypropylene-based graft polymer (E-1) was not used, and only the graft copolymers (G-1) and (G-2) were used, with the resin component composition shown in Table 1.

[0140] The specific gravity (density) and MVR were measured for each of the pellets of Examples 1 to 4 and Comparative Examples 1 to 4. Furthermore, the pellets of the thermoplastic resin composition were molded into various molded articles, and the above-mentioned evaluations were carried out. These results are shown in Table 1. The results of the TEM image analysis performed on Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 2 together with the TEM images.

[0141] [Table 1]

[0142] [Table 2]

[0143] From Table 1, we can see the following: In Examples 1 to 5, no poor appearance or peeling occurred, and further, the variations in millimeter wave characteristics were small, allowing stable performance to be exhibited. In contrast, among Comparative Examples 1 and 2, in which polypropylene resin (A) was blended instead of polypropylene-based graft polymer (E-1), Comparative Example 1, which contained 15% polypropylene, achieved millimeter-wave characteristics on average, but variations were observed. The millimeter-wave characteristics of Comparative Example 2 showed smaller variations, but both Comparative Examples 1 and 2 exhibited significant appearance defects, and the resin layer on the surface around the cut portion of the gate of the test piece was easily peeled off by hand, causing peeling from the resin, making it unsuitable for practical use. Furthermore, Comparative Example 3 uses a polypropylene graft polymer (e-1) whose particle size cannot be confirmed due to solution polymerization, and therefore, although millimeter wave characteristics appear to be exhibited on average, variations are observed. Although Comparative Examples 1 to 3 improve the millimeter wave characteristics of Comparative Example 4, which does not contain the polypropylene-based graft polymer (E-1) or the polypropylene resin (A), they are considered to have problems in terms of practicality and functionality due to poor appearance, peeling, and variations in millimeter wave characteristics.

[0144] Furthermore, it can be seen from Table 2 that the thermoplastic resin composition of the present invention allows the polypropylene resin component to be finely dispersed in the matrix, making it possible to obtain molded articles with excellent appearance. [Industrial Applicability]

[0145] The molded article of the present invention obtained by molding the thermoplastic resin composition of the present invention has excellent impact resistance and appearance, and can stably exhibit millimeter wave characteristics. Therefore, the molded article is suitable for millimeter wave radar parts, radomes for millimeter wave radars, and millimeter wave radars that require these characteristics, and can also be used as vehicle parts. Furthermore, the molded article can be suitably used for ship components and home appliance parts such as communication equipment, office automation equipment, mobile devices, toys, vacuum cleaners, televisions, and air conditioners.

Claims

1. 1 to 80 parts by mass of a polypropylene-based graft polymer (E) obtained by graft polymerizing a vinyl-based monomer (D1) onto polypropylene-based resin particles (C) having a volume average particle diameter of 50 to 850 nm, the polypropylene-based graft polymer (E) comprising 100 parts by mass of a polypropylene resin (A) and 5 to 25 parts by mass of an acid-modified olefin resin (B); 20 to 99 parts by mass of a graft polymer (G) obtained by graft polymerizing a vinyl monomer (D2) onto an ethylene / α-olefin rubber polymer (F) having an ethylene unit content of 50 to 95% by mass, or a mixture containing 5 to 25 parts by mass of an acid-modified olefin resin (B) per 100 parts by mass of the ethylene / α-olefin rubber polymer (F); A thermoplastic resin composition comprising: (wherein the total of the polypropylene-based graft polymer (E) and the graft polymer (G) is 100 parts by mass); of 100% by mass of the vinyl monomer (D1), 50 to 90% by mass is an aromatic vinyl compound, 10 to 50% by mass is a vinyl cyanide compound, and 0 to 30% by mass is another vinyl monomer copolymerizable therewith, A thermoplastic resin composition, wherein, of 100% by mass of the vinyl monomer (D2), 50 to 90% by mass is an aromatic vinyl compound, 10 to 50% by mass is a vinyl cyanide compound, and 0 to 30% by mass is another vinyl monomer copolymerizable therewith.

2. The thermoplastic resin composition according to claim 1, wherein the graft ratio of the polypropylene-based graft polymer (E) is 10 to 70 mass%.

3. 3. The thermoplastic resin composition according to claim 1, wherein the polypropylene-based graft polymer (E) is obtained by graft polymerizing 20 to 70 mass% of a vinyl-based monomer (D1) (wherein the total of the polypropylene-based resin particles (C) and the vinyl-based monomer (D1) is 100 mass%) in the presence of 30 to 80 mass% of polypropylene-based resin particles (C).

4. 4. The thermoplastic resin composition according to claim 1, wherein the polypropylene-based resin particles (C) are obtained by melt-kneading the polypropylene resin (A) and the acid-modified olefin resin (B) and dispersing the resulting kneaded mixture in an aqueous medium.

5. the graft polymer (G) is a rubber-polymer-reinforced vinyl resin having a graft polymer portion derived from an ethylene-α-olefin rubber polymer (F) and a vinyl monomer (D2), and a vinyl resin portion; the content ratios of the graft polymer portion and the vinyl resin portion are 10 to 90% by mass and 90 to 10% by mass, respectively, relative to 100% by mass of the total of these portions; 5. The thermoplastic resin composition according to claim 1, wherein the graft ratio is 20 to 65%.

6. A molded article obtained by molding the thermoplastic resin composition according to any one of claims 1 to 5.

7. A millimeter wave radome comprising the molded article according to claim 6.

8. A millimeter wave radar comprising the millimeter wave radome according to claim 7.

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