Thermoplastic resin composition and thermoplastic resin molded article

Abstract

Provided is a thermoplastic resin composition containing at least one type of thermoplastic resin (L) selected from the group consisting of polycarbonate resins and resins having, as structural units, rubbery polymers, vinyl cyanide monomers, and aromatic vinyl monomers, a paraffin hydrocarbon solvent (M), and a styrene elastomer (N), the thermoplastic resin (L) being one or more types of thermoplastic resin (L) selected from the group consisting of polycarbonate resins and resins having, as structural units, rubbery polymers, vinyl cyanide monomers, and aromatic vinyl monomers. The paraffin hydrocarbon solvent (M) has an aniline point of 110 DEG C or more, and the styrene elastomer (N) is a block copolymer comprising a polymer block having polystyrene and a polymer block having a conjugated diene compound. The thermoplastic resin composition achieves maintenance or improvement of low-temperature impact resistance of a thermoplastic resin, while having excellent silence characteristics.

Description

TECHNICAL FIELD

[0001] The present application relates to a thermoplastic resin composition and a thermoplastic resin molded body. BACKGROUND

[0002] Thermoplastic resins are widely used in the fields of electrical / electronic housings, automotive interior / exterior parts, building materials, furniture, musical instruments, and miscellaneous goods, because of their excellent impact resistance, processability, dimensional stability, and mechanical properties. In addition, they are widely used as various display devices and protective parts for automotive interiors by implementing additional secondary processes such as coating treatment, lamination, and surface modification on extrusion molded products (molded bodies).

[0003] Among thermoplastic resins, polycarbonate (hereinafter referred to as PC) resins or mixed resins of polycarbonate (hereinafter referred to as PC / ABS (acrylonitrile-butadiene-styrene), ABS resins are excellent in impact resistance, processability, flame resistance, or heat resistance, and are used as materials for automotive parts, precision machines, OA equipment, and the like. However, when molded products of the above resins are combined, a squeaking sound can sometimes occur due to contact between the resins. Therefore, in environments where quietness is required, there is a demand for reducing (suppressing) the squeaking sound, which is a characteristic of quietness (squeaking sound suppression effect).

[0004] As a method for improving the quietness characteristic of a thermoplastic resin composition, Patent Literature 1 discloses a thermoplastic resin composition containing a graft copolymer composed of an ethylene-alkyl acrylate copolymer, an ethylene-alkyl acrylate copolymer, a (meth)acrylate copolymer, and an aromatic vinyl monomer, and a styrene-based elastomer.

[0005] In recent years, in order to reduce the burden on the environment, electrification in the automotive industry is continuously advancing, and the quietness of the power source has been dramatically improved compared to engine vehicles. As a result, the quietness of the in-vehicle environment has also progressed, and the demand for quietness characteristics is increasing.

[0006] PRIOR ART DOCUMENTS PATENT LITERATURE Patent Literature 1: International Publication No. 2020 / 162494 SUMMARY

[0007] (1) Problem to be Solved On the other hand, thermoplastic resins for automobile members are used in the vicinity of engines where temperature changes drastically or in a wide range of temperature conditions such as cold regions or tropical regions, and in recent years, impact resistance in a low temperature environment has been particularly required from the viewpoint of safety in a vehicle interior at the time of a collision. However, in a resin composition in which the quietness characteristics have been improved by the conventional method, a new technical problem of a decrease in impact resistance in a low temperature environment (low temperature impact resistance) has been found. The low temperature impact resistance of the thermoplastic resin composition described in Patent Document 1 is not sufficient, and further improvement is required.

[0008] In view of the circumstances as described above, an object of the present application is to provide a thermoplastic resin composition and a thermoplastic resin molded body, which achieve maintenance or improvement of low temperature impact resistance possessed by a thermoplastic resin, while having excellent quietness characteristics.

[0009] (II) Technical Solution That is, the present application has the following configuration.

[0010] (1) A thermoplastic resin composition containing a thermoplastic resin (L), a paraffin-based hydrocarbon solvent (M), and a styrene-based elastomer (N), the thermoplastic resin (L) being one or more selected from the group consisting of a polycarbonate resin, and a resin having a rubbery polymer, a cyano vinyl-based monomer, and an aromatic vinyl-based monomer as a structural unit, the paraffin-based hydrocarbon solvent (M) having an aniline point of 110°C or higher, and the styrene-based elastomer (N) being a block copolymer containing a polymer block having a polystyrene and a polymer block having a conjugated diene compound.

[0011] (2) The thermoplastic resin composition according to (1), wherein the proportion of the paraffin-based hydrocarbon solvent (M) is 1.5 to 8.0 parts by weight, and the proportion of the styrene-based elastomer (N) is 1.0 to 6.0 parts by weight, with respect to 100 parts by weight of the thermoplastic resin (L), and the weight ratio of the paraffin-based hydrocarbon solvent (M) to the styrene-based elastomer (N) ((M) / (N)) is 1 or higher.

[0012] (3) A thermoplastic resin molded body obtained from the thermoplastic resin composition according to (1) or (2).

[0013] (III) Advantageous Effects In the present application, by containing one or more kinds of thermoplastic resin (L) selected from the group consisting of polycarbonate resin, and resin having a rubbery polymer, a cyano vinyl monomer, and an aromatic vinyl monomer as a structural unit, a paraffin hydrocarbon solvent (M) having an aniline point of 110°C or higher, and a styrene elastomer (N), a thermoplastic resin composition and a thermoplastic resin molded body can be obtained, which realizes the maintenance or improvement of the low-temperature impact resistance possessed by the thermoplastic resin, while having excellent quietness characteristics. DETAILED DESCRIPTION

[0014] <Thermoplastic resin composition> The thermoplastic resin composition of the present application contains a thermoplastic resin (L), a paraffin hydrocarbon solvent (M), and a styrene elastomer (N).

[0015] <Thermoplastic resin (L)> The thermoplastic resin (L) is one or more kinds selected from the group consisting of polycarbonate resin, and resin having a rubbery polymer, a cyano vinyl monomer, and an aromatic vinyl monomer as a structural unit. The thermoplastic resin (L) can be used alone or two or more kinds can be used simultaneously.

[0016] The polycarbonate resin is not limited to a particular kind. For example, an aromatic polycarbonate prepared by a known phosgene method or a melt method, etc. can be used. The specific preparation method is described, for example, in Japanese Patent Application Publication No. S63-215763 or Japanese Patent Application Publication No. H2-124934, etc. As a representative bisphenol that can be used as a raw material, 2,2-bis(4-hydroxyphenyl)propane (so-called bisphenol A) can be mentioned. In addition, as a precursor substance for introducing a carbonate, phosgene, diphenyl carbonate, etc. can be mentioned. The prepared polycarbonate resin can use a substance in which the terminal OH group is capped, or a substance in which the terminal OH group is not capped.

[0017] The resin having a rubbery polymer, a cyano vinyl monomer, and an aromatic vinyl monomer as a structural unit can be obtained, for example, by a method in which a monomer component containing the cyano vinyl monomer, the aromatic vinyl monomer, and, if necessary, any other copolymerizable monomer is graft-polymerized in the presence of the rubbery polymer, etc. As the polymerization method, a known method such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc. can be mentioned.

[0018] As the rubbery polymer, for example, diene-based rubber, acrylic rubber, ethylene-propylene-based rubber, and the like can be exemplified. As the diene-based rubber, for example, polybutadiene rubber, acrylonitrile-butadiene copolymer rubber, styrene-butadiene copolymer rubber, polyisoprene rubber, and the like can be exemplified. Further, as the acrylic rubber, for example, acrylic rubber having α, β-unsaturated carboxylic acid in a structural unit such as acrylic acid, methacrylic acid, and the like; acrylic rubber having α, β-unsaturated carboxylic acid ester in a structural unit such as methyl methacrylate, ethyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, and the like; and the like can be exemplified. As the ethylene-propylene-based rubber, EPR, EPDM, and the like can be exemplified. The rubbery polymer can be used alone or two or more kinds thereof can be used simultaneously.

[0019] As the cyanoethylene monomer, for example, acrylonitrile, methacrylonitrile, and the like can be exemplified, of which acrylonitrile is preferable. The cyanoethylene monomer can be used alone or two or more kinds thereof can be used simultaneously.

[0020] As the aromatic vinyl monomer, for example, styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-t-butylstyrene, and the like can be exemplified, of which styrene, α-methylstyrene are preferable. The aromatic vinyl monomer can be used alone or two or more kinds thereof can be used simultaneously.

[0021] As the other copolymerizable monomer, for example, α, β-unsaturated carboxylic acid such as acrylic acid, methacrylic acid, and the like; α, β-unsaturated carboxylic acid ester such as methyl methacrylate, ethyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, and the like; imide compound of α, β-unsaturated dicarboxylic acid such as maleic anhydride, itaconic anhydride, and the like can be exemplified. The other copolymerizable monomer can be used alone or two or more kinds thereof can be used simultaneously.

[0022] As the resin having the rubbery polymer, the cyanoethylene monomer, and the aromatic vinyl monomer as a structural unit, for example, ABS resin, ASA resin, AES resin, and the like can be exemplified.

[0023] As the ABS-based resin, for example, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-butadiene-styrene-α-methylstyrene copolymer, acrylonitrile-butadiene-styrene-N-phenylmaleimide copolymer, and the like can be exemplified.

[0024] When the thermoplastic resin (L) is a mixed resin of a resin having a rubbery polymer, a cyanoethylene monomer, and an aromatic vinyl monomer as a structural unit and a PC resin, the content of the PC resin is preferably 50 to 95 parts by weight, if the total is 100 parts by weight. Thereby, a thermoplastic resin composition having particularly excellent mechanical properties can be obtained.

[0025] <Paraffin-based hydrocarbon solvent (M)> The paraffin-based hydrocarbon solvent (M) is classified in a ring analysis (n-d-M method, ASTM D3238-85) frequently used for base oil component analysis, in terms of the ratio of the number of paraffin carbon atoms to the total carbon atoms being set as %CP, which is preferably 50% or more, more preferably 60% or more, and further preferably 70% or more. Also, %CP is preferably 90% or less, and more preferably 85% or less. That is, %CP of the paraffin-based hydrocarbon solvent (M) is preferably 50% or more and 90% or less, more preferably 60% or more and 85% or less, and further preferably 70% or more and 85% or less.

[0026] Further, from the viewpoint of low-temperature impact resistance of the thermoplastic resin composition, the aniline point (JIS K2256) of the paraffin-based hydrocarbon solvent (M) is 110°C or more, preferably 115°C or more, and more preferably 120°C or more. Also, the aniline point is preferably 150°C or less, and more preferably 140°C or less. That is, from the viewpoint of low-temperature impact resistance of the thermoplastic resin composition, the aniline point of the paraffin-based hydrocarbon solvent (M) is preferably 115°C or more and 150°C or less, and more preferably 120°C or more and 140°C or less.

[0027] Further, from the viewpoint of low-temperature impact resistance of the thermoplastic resin composition, the kinematic viscosity at 100°C (JIS K2283) of the paraffin-based hydrocarbon solvent (M) is preferably 20 mm 2 / s or more, and more preferably 25 mm 2 / s or more. Also, the kinematic viscosity at 100°C is preferably 100 mm 2 / s or less, and more preferably 50 mm 2 / s or less. That is, from the viewpoint of low-temperature impact resistance of the thermoplastic resin composition, the kinematic viscosity at 100°C of the paraffin-based hydrocarbon solvent (M) is preferably 20 mm 2 / s or more and 100 mm 2 / s or less, and more preferably 25 mm 2 / s or more and 50 mm 2 / s or less.

[0028] From the viewpoint of improving low-temperature impact resistance, in the thermoplastic resin composition, the contained proportion of the paraffin-based hydrocarbon solvent (M) is preferably 1.5 to 8.0 parts by weight, more preferably 2.0 to 6.0 parts by weight, and further preferably 2.5 to 5.0 parts by weight or more, with respect to 100 parts by weight of the thermoplastic resin (L).

[0029] <Styrene-based elastomer (N)> The styrenic elastomer (N) is a block copolymer comprising a polymer block D with polystyrene as the main component and a polymer block E with a conjugated diene compound as the main component. The styrenic elastomer (N) can be exemplified by a block copolymer having a structure of D-E, D-E-D, E-D-E-D, and D-E-D-E-D, and the like. From the viewpoint of molding processability, the number of polymer blocks D in the molecule of the styrenic elastomer (N) is preferably two or more. Furthermore, in the polymer block E, the bonding mode of the conjugated diene compound is not particularly limited and can be arbitrary. When there are two or more polymer blocks E in the molecule, they can be the same structure or different structures. The styrenic elastomer (N) can be used alone or two or more can be used simultaneously.

[0030] The hydrogenation rate of the styrenic elastomer (N) (the ratio of the number of single bonds between carbon atoms by hydrogenation to the number of double bonds between carbon atoms in the block copolymer of polystyrene and the conjugated diene compound before hydrogenation) is not particularly limited and is usually 50 parts by weight or more, preferably 70 parts by weight or more, and more preferably 90 parts by weight or more.

[0031] As the styrenic elastomer (N), for example, a styrene-isoprene-styrene block copolymer (SIS), a styrene-butadiene-styrene block copolymer (SBS), a styrene-ethylene-butylene block copolymer (SEB), a styrene-ethylene-propylene block copolymer (SEP), a styrene-ethylene-butylene-styrene block copolymer (SEBS), a styrene-ethylene-propylene-styrene copolymer block (SEPS), a styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), a styrene-vinyl (ethylene-propylene)-styrene copolymer (V-SEPS), and the like can be exemplified. Among them, from the viewpoint of improving the quietness characteristics, a styrene-ethylene-butylene-styrene block copolymer (SEBS), a styrene-ethylene-propylene-styrene block copolymer (SEPS) is preferred.

[0032] Further, the thermoplastic resin composition of the present application can also use various blending agents. As the blending agents, for example, there can be listed fiber reinforcing materials such as ceramic fiber (CF), glass fiber, aramid fiber, potassium titanate fiber, mineral broken fiber, silica fiber, alumina fiber, gypsum fiber, magnesium hydroxide fiber, silicon carbide fiber, zirconia fiber, and the like; various shapes of organic or inorganic fillers such as spherical silica, mica, wollastonite, calcium carbonate, kaolin, clay, bentonite, sericite, glass beads, glass flakes, alumina, calcium silicate, magnesium carbonate, talc, zinc oxide, titanium oxide, iron oxide, graphite, carbon black, molybdenum disulfide, ultra-high-density polyethylene, and the like; lubricants such as mineral oil, hydrocarbon, fatty acid, fatty acid ester, fatty acid amide, alcohol, metal soap, natural wax, silicone, and the like; processing aids such as PTFE-based, acrylic-based, and the like; inorganic flame retardants such as magnesium hydroxide, aluminum hydroxide, and the like; organic flame retardants such as halogen-based, phosphorus-based, and the like; antioxidants, ultraviolet light resistant agents, light stabilizers, colorants, antistatic agents, crosslinking agents, dispersants, coupling agents, foaming agents, colorants, and the like.

[0033] In the thermoplastic resin composition, from the viewpoint of improving the quietness characteristics and low-temperature impact resistance, the content ratio of the styrenic elastomer (N) with respect to 100 parts by weight of the thermoplastic resin (L) is preferably 1.0 to 6.0 parts by weight, more preferably 1.5 to 5.0 parts by weight, and further preferably 1.5 to 4.0 parts by weight.

[0034] From the viewpoint of improving the low-temperature impact resistance, in the thermoplastic resin composition, the weight ratio ((M) / (N)) of the paraffin-based hydrocarbon solvent (M) to the styrenic elastomer (N) is preferably 1 or more, more preferably 1.5 or more, and preferably 3 or less. That is, from the viewpoint of improving the low-temperature impact resistance, in the thermoplastic resin composition, the weight ratio ((M) / (N)) of the paraffin-based hydrocarbon solvent (M) to the styrenic elastomer (N) is preferably 1 or more and 3 or less, more preferably 1.5 or more and 3 or less.

[0035] The thermoplastic resin composition of the present application can be obtained by melt kneading the thermoplastic resin (L), the paraffin-based hydrocarbon solvent (M), the styrenic elastomer (N), and optional various blending agents. As the melt kneading, for example, there can be listed a method of melt kneading using a Banbury mixer, a kneader, a kneading extruder, a twin-screw extruder, a roll, and the like. Further, the respective components described above can be added and kneaded in any order, or can be added and kneaded simultaneously. The number of times of kneading can be one or more. The time of kneading varies depending on the size of the kneader used and the like, and is usually about 3 to 10 minutes. Further, the discharge temperature of the kneader is preferably set to 150 to 350°C, and more preferably to 180 to 250°C.

[0036] The thermoplastic resin molded body of the present application can be obtained by molding the thermoplastic resin composition into a prescribed shape. As the molding method, there is no particular limitation, and for example, injection molding, extrusion molding, and the like can be cited, and the heating temperature, pressure, time, and the like of the molding can be appropriately set. The thermoplastic resin molded body is excellent in the quietness characteristic and the low-temperature impact resistance, and thus can be used as an electrical component, an electronic component, a mechanical component, a precision equipment component, an automobile component.

[0037] Examples The present application is further explained by the following examples, but the present application is not limited only by these examples.

[0038] Preparation of the thermoplastic resin composition Example 1 As the thermoplastic resin (L), 100 g of a PC / ABS resin (trade name "Multilon T-2711J", manufactured by TEIJIN LIMITED), 3.0 g of a paraffin-based hydrocarbon solvent (M) (trade name "SUNFLEX 2280", manufactured by JAPAN SUNOIL COMPANY, LTD.), and 2.0 g of a styrene-based elastomer (N) (trade name "Kraton G1651", manufactured by KRATON POLYMERS K.K.) were dry-mixed. Then, melt kneading was performed using a twin-screw extruder (PCM-30: manufactured by IKEGAI CO., LTD.) (kneading conditions... shaft rotation speed: 100 rpm, feeder rotation speed: 10 rpm, extrusion temperature: 220 to 240°C, discharge amount: 3.5 kg / h). Subsequently, after obtaining a resin composition in the form of a strip, it was cut into a granular shape (granular size (cross-sectional diameter): 1.0 to 3.0 mm), thereby obtaining a thermoplastic resin composition.

[0039] Examples 2 to 8, Comparative Examples 1 to 4 A thermoplastic resin composition was prepared in the same manner as in Example 1, except that the kind and blending amount (parts by weight) of each raw material were changed as shown in Tables 1 to 3.

[0040] The results of evaluation by the following evaluation methods using the thermoplastic resin compositions of each of the examples and comparative examples obtained above are shown in Tables 2 and 3.

[0041] Evaluation of the quietness characteristic The pellets obtained above were injection-molded (cylinder temperature: 250 to 260°C, mold temperature: 80°C) to produce evaluation test pieces (length: 60 mm x width: 100 mm x thickness: 2 mm). Next, a board (55 mm x 80 mm x 2 mm) for a squeak property test was cut from the test pieces (evaluation material) and deburred, and then left to stand for 12 hours at a temperature of 25°C and a humidity of 50% RH, and then left to stand for 300 hours at a temperature of 80°C and a humidity of 50% RH. In addition, the thermoplastic resin (L) was injection-molded and used as a counter material. Next, the board for the squeak property test and the board for the counter material were fixed to a stick-slip measuring device SSP-04 of Ziegler, and the squeak risk value at the time of friction with each other was measured under conditions of a load = 40 N and a speed = 1 mm / s, and evaluated according to the following evaluation criteria.

[0042] Squeak risk value 1: extremely low risk of squeak ( ) Squeak risk value 2 to 3: low risk of squeak (O) Squeak risk value 4 to 10: high risk of squeak (X) The thermoplastic resin molded body of the present application has a target of 3 or less for the squeak risk value in the evaluation of the above-mentioned squeak property.

[0043] Evaluation of low-temperature impact resistance Each of the pellets obtained above and the thermoplastic resin (L) was injection-molded (cylinder temperature: 250 to 260°C, mold temperature: 80°C) to produce a test piece with a notch (length: 80 mm x width: 10 mm x thickness: 4 mm). The Charpy impact strength (unit: kJ / m 2 ) at -30°C was measured in accordance with ISO 179, the impact strength retention rate (%) was calculated according to Formula (1), and evaluated according to the following evaluation criteria.

[0044] Impact strength retention rate (%) = {(impact strength of the thermoplastic resin composition / impact strength of the thermoplastic resin (L)) x 100} (Formula (1)) : impact strength retention rate (%) is 110% or more : impact strength retention rate (%) is 90% or more and less than 110% : impact strength retention rate (%) is less than 90% The thermoplastic resin molded body of the present application has a target of 90% or more for the above-mentioned impact strength retention rate (%).

[0045] [Table 1] [Table 2] [Table 3] In Tables 1 to 3, L1 represents a PC / ABS resin (manufactured by TEIJIN LIMITED, trade name "Multilon T-2711J", low-temperature impact resistance grade); L2 represents a PC / ABS resin (manufactured by TORAY INDUSTRIES, INC., trade name "TOYOLAC PX10-X07", standard grade); L3 represents an ABS resin (manufactured by Techno-UMG Co., Ltd., trade name "UMG ABS EX141", standard grade); M1 represents a paraffin-based hydrocarbon solvent (manufactured by JAPAN SUN OIL COMPANY, LTD., trade name "SUNFLEX 2280", aniline point: 122.4°C, kinematic viscosity (100°C): 31.7 mm 2 / s, CP: 71%); M2 represents a paraffin-based hydrocarbon solvent (manufactured by JAPAN SUN OIL COMPANY, LTD., trade name "SUNPAR 2280", aniline point: 132.7°C, kinematic viscosity (100°C): 31.4 mm 2 / s, CP: 71%); M'1 represents a paraffin-based hydrocarbon solvent (manufactured by JAPAN SUN OIL COMPANY, LTD., trade name "SUNPAR 110", aniline point: 104.3°C, kinematic viscosity (100°C): 4.2 mm 2 / s, CP: 67%); M'2 represents a naphthene-based hydrocarbon solvent (manufactured by JAPAN SUN OIL COMPANY, LTD., trade name "SUNTHENE 4240", aniline point: 87.9°C, kinematic viscosity (100°C): 18.3 mm 2 / s, CP: 45%); N1 represents a styrene-ethylene-butylene-styrene (SEBS) block copolymer (manufactured by KOTEN POLYMERS CO., LTD., trade name "Kraton G1651"); N2 represents a styrene-ethylene-propylene-styrene (SEPS) block copolymer (manufactured by KURARAY CO., LTD., trade name "Septon 2006").

[0046] In the thermoplastic resin compositions of Examples 1 to 8, evaluation results in which the quietness characteristics and the low-temperature impact resistance satisfied the target values were obtained.

[0047] Comparative Example 1 had poor low-temperature impact resistance because the aniline point of the paraffin-based hydrocarbon solvent (M'1) was low.

[0048] Comparative Example 2 had poor low-temperature impact resistance because the naphthene-based hydrocarbon solvent (M'2) having a low aniline point was included instead of the paraffin-based hydrocarbon solvent (M).

[0049] Comparative Example 3 had poor quietness characteristics because the styrene-based elastomer (N) was not included.

[0050] Comparative Example 4 had poor low-temperature impact resistance because the paraffin-based hydrocarbon solvent (M) was not included.

Claims

1. A thermoplastic resin composition, characterized in that, It contains thermoplastic resin (L), paraffinic hydrocarbon solvent (M), and styrene elastomer (N). The thermoplastic resin (L) is selected from one or more resins grouped together with polycarbonate resins and resins whose structural units are rubber polymers, cyanide monomers and aromatic vinyl monomers. The aniline point of the paraffinic hydrocarbon solvent (M) is above 110°C. The styrene-based elastomer (N) is a block copolymer comprising polymer blocks having polystyrene and polymer blocks having conjugated diene compounds.

2. The thermoplastic resin composition according to claim 1, characterized in that, The proportion of the paraffinic hydrocarbon solvent (M) and the proportion of the styrene-based elastomer (N) are 1.5 to 8.0 parts by weight relative to 100 parts by weight of the thermoplastic resin (L). The weight ratio ((M) / (N)) of the paraffinic hydrocarbon solvent (M) to the styrene elastomer (N) is 1 or more.

3. A thermoplastic resin molded article, characterized in that, The thermoplastic resin molded body is obtained from the thermoplastic resin composition according to claim 1 or 2.

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