Thermoplastic resin composition and thermoplastic resin molded article

Abstract

Provided is a thermoplastic resin composition containing a thermoplastic resin (L), a paraffin-based hydrocarbon solvent (M), and a styrene-based elastomer (N), wherein: the thermoplastic resin (L) is at least one selected from the group consisting of a polycarbonate resin, and a resin having a rubbery polymer, a vinyl cyanide-based monomer, and an aromatic vinyl-based monomer as a constituent unit; the paraffin-based hydrocarbon solvent (M) has an aniline point of at least 110 °C; and the styrene-based elastomer (N) is a block copolymer including a polymer block having polystyrene and a polymer block having a conjugated diene compound. The thermoplastic resin composition has excellent noise-reduction characteristics while maintaining or improving the low-temperature impact resistance of a thermoplastic resin.

Description

Thermoplastic resin composition and thermoplastic resin molded article

[0001] The present invention relates to a thermoplastic resin composition and a thermoplastic resin molded article.

[0002] Due to their excellent impact resistance, processability, dimensional stability, and mechanical properties, thermoplastic resins are used in a wide range of fields, including electrical and electronic housings, automotive interior and exterior parts, building materials, furniture, musical instruments, and miscellaneous goods. Furthermore, extrusion molded products (molded bodies) are widely used as various display devices and protective parts for automotive interiors by undergoing additional secondary processing such as coating, lamination, and surface modification.

[0003] Among thermoplastic resins, polycarbonate (hereinafter referred to as PC) resin and polycarbonate mixed resin (hereinafter referred to as PC / ABS (acrylonitrile-butadiene-styrene)) ABS resin have excellent impact resistance, processability, flame resistance, and heat resistance, and are used as materials for automobile parts, precision machinery, office equipment, etc. However, when molded products of the above resins are combined, creaking noises may occur due to contact between the resins. Therefore, in environments where quietness is required, there is a demand for noise reduction characteristics (creaking noise suppression effect) such as reducing (suppressing) creaking noises.

[0004] As a method for improving the noise reduction properties of a thermoplastic resin composition, Patent Document 1 discloses a thermoplastic resin composition containing an ethylene-acrylic acid alkyl ester copolymer, an ethylene-acrylic acid alkyl ester copolymer, a (meth)acrylic acid alkyl ester copolymer, a graft copolymer composed of an aromatic vinyl monomer, and a styrene-based elastomer.

[0005] In recent years, the automotive industry has been moving toward electrification in order to reduce the burden on the environment, and the quietness of power sources has improved dramatically compared to engine vehicles. This has led to a quieter in-car environment, and the demand for quieter performance is increasing.

[0006] International Publication No. 2020 / 162494

[0007] On the other hand, thermoplastic resins for automotive components are used in engines where temperature changes are severe, and under a wide range of temperature conditions, such as in cold and tropical regions. In recent years, impact resistance, particularly in low-temperature environments, has been required for safety reasons within the vehicle interior during a collision. However, a new problem has been found in resin compositions in which noise reduction properties have been improved by conventional methods: impact resistance in low-temperature environments (low-temperature impact resistance) is reduced. The thermoplastic resin composition described in Patent Document 1 has insufficient low-temperature impact resistance, and further improvement has been required.

[0008] In view of the above circumstances, an object of the present invention is to provide a thermoplastic resin composition and a thermoplastic resin molded article that have excellent noise reduction properties while maintaining or improving the low-temperature impact resistance of thermoplastic resins.

[0009] That is, the present invention has the following configuration: [1] A thermoplastic resin composition containing a thermoplastic resin (L), a paraffinic hydrocarbon solvent (M), and a styrene-based elastomer (N), wherein the thermoplastic resin (L) is at least one selected from the group consisting of polycarbonate resins and resins having structural units of a rubber polymer, a vinyl cyanide monomer, and an aromatic vinyl monomer, the paraffinic hydrocarbon solvent (M) has an aniline point of 110°C or higher, and the styrene-based elastomer (N) is a block copolymer containing a polymer block having polystyrene and a polymer block having a conjugated diene compound. [2] The thermoplastic resin composition according to [1], wherein the proportion of the paraffinic hydrocarbon solvent (M) is 1.5 to 8.0 parts by weight, the proportion of the styrene elastomer (N) is 1.0 to 6.0 parts by weight, and the weight ratio of the paraffinic hydrocarbon solvent (M) to the styrene elastomer (N) ((M) / (N)) is preferably at least 1, relative to 100 parts by weight of the thermoplastic resin (L). [3] A thermoplastic resin molded article obtained from the thermoplastic resin composition according to [1] or [2].

[0010] In the present invention, by containing one or more thermoplastic resins (L) selected from the group consisting of polycarbonate resins and resins having structural units of rubber polymers, vinyl cyanide monomers, and aromatic vinyl monomers, a paraffinic hydrocarbon solvent (M) having an aniline point of 110°C or higher, and a styrene elastomer (N), it is possible to obtain a thermoplastic resin composition and a thermoplastic resin molded article that have excellent noise-reduction properties while maintaining or improving the low-temperature impact resistance of the thermoplastic resin.

[0011] <Thermoplastic Resin Composition> The thermoplastic resin composition of the present invention contains a thermoplastic resin (L), a paraffinic hydrocarbon solvent (M), and a styrene-based elastomer (N).

[0012] <Thermoplastic resin (L)> The thermoplastic resin (L) is at least one selected from the group consisting of polycarbonate resins and resins having a rubber polymer, a vinyl cyanide monomer, and an aromatic vinyl monomer as structural units. The thermoplastic resin (L) may be used alone or in combination of two or more.

[0013] The polycarbonate resin is not limited to a specific type. For example, aromatic polycarbonates produced by the known phosgene method or melt method can be used. Specific production methods are described in, for example, Japanese Patent Application Laid-Open Nos. 63-215763 and 2-124934. A typical diphenol used as a raw material is 2,2-bis(4-hydroxyphenyl)propane (known as bisphenol A). Precursors for introducing carbonate include phosgene and diphenyl carbonate. The produced polycarbonate resin can be used either with or without capped terminal OH groups.

[0014] The resin having the rubber polymer, the vinyl cyanide monomer, and the aromatic vinyl monomer as constituent units can be obtained, for example, by graft polymerizing, in the presence of the rubber polymer, a monomer component containing the vinyl cyanide monomer, the aromatic vinyl monomer, and, if necessary, any other copolymerizable monomer. Examples of the polymerization method include known methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization.

[0015] Examples of the rubbery polymer include diene rubber, acrylic rubber, and ethylene-propylene rubber. Examples of the diene rubber include polybutadiene rubber, acrylonitrile-butadiene copolymer rubber, styrene-butadiene copolymer rubber, and polyisoprene rubber. Examples of the acrylic rubber include acrylic rubbers having α,β-unsaturated carboxylic acids such as acrylic acid and methacrylic acid as structural units; and acrylic rubbers having α,β-unsaturated carboxylic acid esters such as methyl methacrylate, ethyl methacrylate, t-butyl methacrylate, and cyclohexyl methacrylate as structural units. Examples of the ethylene-propylene rubber include EPR and EPDM. The rubbery polymers may be used alone or in combination of two or more.

[0016] Examples of the vinyl cyanide monomer include acrylonitrile and methacrylonitrile, and among these, acrylonitrile is preferred. The vinyl cyanide monomer may be used alone or in combination of two or more kinds.

[0017] Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, and p-t-butylstyrene, and among these, styrene and α-methylstyrene are preferred. The aromatic vinyl monomers may be used alone or in combination of two or more.

[0018] Examples of the other copolymerizable monomer include α,β-unsaturated carboxylic acids such as acrylic acid and methacrylic acid, α,β-unsaturated carboxylic acid esters such as methyl methacrylate, ethyl methacrylate, t-butyl methacrylate, and cyclohexyl methacrylate, and imide compounds of α,β-unsaturated dicarboxylic acids such as maleic anhydride and itaconic anhydride. The other copolymerizable monomers may be used alone or in combination of two or more.

[0019] Examples of the resin having a rubber polymer, a vinyl cyanide monomer, and an aromatic vinyl monomer as constituent units include ABS resin, ASA resin, and AES resin.

[0020] Examples of the ABS resin include acrylonitrile-butadiene-styrene copolymer, acrylonitrile-butadiene-styrene-α-methylstyrene copolymer, and acrylonitrile-butadiene-styrene-N-phenylmaleimide copolymer.

[0021] When the thermoplastic resin (L) is a mixed resin of a rubber polymer, a resin having constituent units of a vinyl cyanide monomer and an aromatic vinyl monomer, and a PC resin, the content of the PC resin is preferably 50 to 95 parts by weight per 100 parts by weight of the total, which allows a thermoplastic resin composition having particularly excellent mechanical properties to be obtained.

[0022] <Paraffinic Hydrocarbon Solvent (M)> The paraffinic hydrocarbon solvent (M) is classified by the ratio of the number of paraffin carbon atoms to the total carbon atoms, expressed as %CP, in ring analysis (ndM method, ASTM D3238-85), which is frequently used in analyzing the composition of base oils. The %CP is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more. The %CP is preferably 90% or less, and even more preferably 85% or less. That is, the %CP of the paraffinic hydrocarbon solvent (M) is preferably 50% or more and 90% or less, more preferably 60% or more and 85% or less, and even more preferably 70% or more and 85% or less.

[0023] Furthermore, from the viewpoint of the low-temperature impact resistance of the thermoplastic resin composition, the paraffinic hydrocarbon solvent (M) has an aniline point (JIS K2256) of 110°C or higher, preferably 115°C or higher, and more preferably 120°C or higher. The aniline point is preferably 150°C or lower, and more preferably 140°C or lower. That is, from the viewpoint of the low-temperature impact resistance of the thermoplastic resin composition, the paraffinic hydrocarbon solvent (M) has an aniline point of preferably 115°C or higher and 150°C or lower, and more preferably 120°C or higher and 140°C or lower.

[0024] Furthermore, from the viewpoint of low-temperature impact resistance of the thermoplastic resin composition, the paraffin-based hydrocarbon solvent (M) should have a kinematic viscosity (JIS K2283) of 20 mm at 100°C. ２ / s or more, and 25 mm ２ It is more preferable that the kinematic viscosity at 100°C is 100mm / s or more. ２ / s or less, and ２ That is, from the viewpoint of the low-temperature impact resistance of the thermoplastic resin composition, the paraffinic hydrocarbon solvent (M) has a kinematic viscosity of 20 mm / s or less at 100°C. ２ / s or more 100mm ２ / s or less, and ２ / s or more: 50 mm ２ It is more preferable that the value is equal to or less than 1 / s.

[0025] In the thermoplastic resin composition, the content of the paraffinic hydrocarbon solvent (M) is preferably 1.5 to 8.0 parts by weight, more preferably 2.0 to 6.0 parts by weight, and even more preferably 2.5 to 5.0 parts by weight or more, relative to 100 parts by weight of the thermoplastic resin (L), from the viewpoint of improving low-temperature impact resistance.

[0026] <Styrene-Based Elastomer (N)> The styrene-based elastomer (N) is a block copolymer containing a polymer block D mainly composed of polystyrene and a polymer block E mainly composed of a conjugated diene compound. Examples of the styrene-based elastomer (N) include block copolymers having structures such as DE, D-ED, E-D-ED, and D-ED-ED-D. From the viewpoint of moldability, the styrene-based elastomer (N) preferably contains two or more polymer blocks D in the molecule. Furthermore, in the polymer block E, the bonding mode between the conjugated diene compound and the conjugated diene compound is not particularly limited and can be any bonding mode. When two or more polymer blocks E are present in the molecule, they may have the same structure or different structures. The styrene-based elastomer (N) may be used alone or in combination of two or more types.

[0027] The hydrogenation rate of the styrene elastomer (N) (the ratio of the number of carbon-carbon single bonds resulting from hydrogenation to the number of carbon-carbon double bonds in the block copolymer of polystyrene and the conjugated diene compound before hydrogenation) is not particularly limited, but is usually 50 parts by weight or more, preferably 70 parts by weight or more, and more preferably 90 parts by weight or more.

[0028] Examples of the styrene elastomer (N) include styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-butene block copolymer (SEB), styrene-ethylene-propylene block copolymer (SEP), styrene-ethylene-butene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-vinyl(ethylene-propylene)-styrene copolymer (V-SEPS), etc. Among these, from the viewpoint of improving noise reduction properties, styrene-ethylene-butene-styrene block copolymer (SEBS) and styrene-ethylene-propylene-styrene block copolymer (SEPS) are preferred.

[0029] The thermoplastic resin composition of the present invention can contain various compounding agents, such as fiber reinforcement materials such as ceramic fiber (CF), glass fiber, aramid fiber, potassium titanate fiber, crushed mineral fiber, silica fiber, alumina fiber, gypsum fiber, magnesium hydroxide fiber, silicon carbide fiber, and zirconia fiber; 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; Examples of suitable additives include organic or inorganic fillers in various forms such as carbon black, molybdenum disulfide, and ultra-high density polyethylene; lubricants such as mineral oil, hydrocarbons, fatty acids, fatty acid esters, fatty acid amides, alcohols, metallic soaps, natural waxes, and silicones; processing aids such as PTFE and acrylic; inorganic flame retardants such as magnesium hydroxide and aluminum hydroxide; organic flame retardants such as halogen-based and phosphorus-based flame retardants; antioxidants, ultraviolet inhibitors, light stabilizers, colorants, antistatic agents, crosslinking agents, dispersants, coupling agents, foaming agents, and colorants.

[0030] In the thermoplastic resin composition, the content of the styrene-based elastomer (N) is preferably 1.0 to 6.0 parts by weight, more preferably 1.5 to 5.0 parts by weight, and even more preferably 1.5 to 4.0 parts by weight, relative to 100 parts by weight of the thermoplastic resin (L), from the viewpoint of improving noise reduction characteristics and low-temperature impact resistance.

[0031] In the thermoplastic resin composition, the weight ratio ((M) / (N)) of the paraffinic hydrocarbon solvent (M) to the styrene elastomer (N) is preferably 1 or more, more preferably 1.5 or more, and preferably 3 or less, from the viewpoint of improving low-temperature impact resistance. That is, in the thermoplastic resin composition, the weight ratio ((M) / (N)) of the paraffinic hydrocarbon solvent (M) to the styrene elastomer (N) is preferably 1 or more and 3 or less, more preferably 1.5 or more and 3 or less, from the viewpoint of improving low-temperature impact resistance.

[0032] The thermoplastic resin composition of the present invention can be obtained by melt-kneading the thermoplastic resin (L), the paraffinic hydrocarbon solvent (M), the styrene-based elastomer (N), and any of the various compounding ingredients. Examples of the melt-kneading method include melt-kneading using a kneader such as a Banbury mixer, kneader, kneading extruder, twin-screw extruder, or roll mill. The components may be added and kneaded in any order, or simultaneously. Kneading may be performed once or multiple times. The kneading time varies depending on the size of the kneader used, but is typically approximately 3 to 10 minutes. The discharge temperature of the kneader is preferably 150 to 350°C, more preferably 180 to 250°C.

[0033] The thermoplastic resin molded article of the present invention can be obtained by molding the thermoplastic resin composition into a predetermined shape. The molding method is not limited to, but examples include, injection molding, extrusion molding, etc., and the heating temperature, pressure, time, etc. of the molding can be appropriately set. The thermoplastic resin molded article has excellent noise reduction properties and low-temperature impact resistance, and can be used as electrical parts, electronic parts, machine parts, precision instrument parts, and automotive parts.

[0034] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0035] <Production of Thermoplastic Resin Composition> <Example 1> 100 g of a PC / ABS resin (trade name "Multilon T-2711J", manufactured by Teijin Limited) was used as the thermoplastic resin (L), 3.0 g of a paraffinic hydrocarbon solvent (M) (trade name "SUNFLEX 2280", manufactured by Nippon San Oil Co., Ltd.), and 2.0 g of a styrene-based elastomer (N) (trade name "Kraton G1651", manufactured by Kraton Polymers Co., Ltd.) were dry-blended. The mixture was then melt-kneaded 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 rate: 3.5 kg / h). Strands of the resin composition were then obtained, which were then cut into pellets (pellet size (cut surface diameter): 1.0 to 3.0 mm) to obtain a thermoplastic resin composition.

[0036] Examples 2 to 8, Comparative Examples 1 to 4 Thermoplastic resin compositions were produced in the same manner as in Example 1, except that the types of raw materials and their blending amounts (parts by weight) were changed as shown in Tables 1 to 3.

[0037] The thermoplastic resin compositions of the Examples and Comparative Examples obtained above were evaluated by the following evaluation methods, and the results are shown in Tables 2 and 3.

[0038] <Evaluation of noise reduction properties> The pellets obtained above were injection molded (barrel temperature: 250-260°C, mold temperature: 80°C) to prepare evaluation test pieces (length: 60 mm x width: 100 mm x thickness: 2 mm). Next, the test piece (evaluation material) was cut into a noise reduction property test plate (55 mm x 80 mm x 2 mm) and deburred. After that, it was left at a temperature of 25°C and a humidity of 50% RH for 12 hours, and then left at a temperature of 80°C and a humidity of 50% RH for 300 hours. In addition, a thermoplastic resin (L) was injection molded and used as the mating material. Next, the noise reduction property test plate and the mating material plate were fixed to a Ziegler stick-slip measuring device SSP-04, and the squeak risk value was measured when they were rubbed together under conditions of a load of 40 N and a speed of 1 mm / s, and evaluated according to the following criteria. Squeaking noise risk value 1: Extremely low risk of squeaking noise (◎) Squeaking noise risk value 2-3: Low risk of squeaking noise (〇) Squeaking noise risk value 4-10: High risk of squeaking noise (×)

[0039] The thermoplastic resin molded article of the present invention was targeted to have a squeak risk value of 3 or less in the above evaluation of noise reduction properties.

[0040] <Evaluation of low-temperature impact resistance> The pellets and thermoplastic resin (L) obtained above were each injection molded (barrel temperature: 250 to 260°C, mold temperature: 80°C) to prepare notched test specimens (length: 80 mm x width: 10 mm x thickness: 4 mm). Charpy impact strength (unit: kJ / m) at -30°C was measured in accordance with ISO 179. ２ ) was measured, and the impact strength retention rate (%) was calculated using formula (1), and evaluated according to the following criteria: Impact strength retention rate (%) = {(impact strength of thermoplastic resin composition / impact strength of thermoplastic resin (L)) × 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%

[0041] The thermoplastic resin molded article of the present invention is targeted to have an impact strength retention rate (%) of 90% or more.

[0042]

[0043]

[0044]

[0045] 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 "UMGABS EX141", standard grade); and M1 represents a paraffinic hydrocarbon solvent (manufactured by Japan Sun Oil Co., Ltd., trade name "SUNFLEX 2280", aniline point: 122.4°C, kinematic viscosity (100°C): 31.7 mm ２ / s, %CP: 71%); M2 is a paraffinic hydrocarbon solvent (manufactured by Japan Sun Oil Co., Ltd., trade name "SUNPAR2280", aniline point: 132.7°C, kinematic viscosity (100°C): 31.4 mm ２ / s, %CP: 71%); M'1 is a paraffinic hydrocarbon solvent (manufactured by Japan Sun Oil Co., Ltd., trade name "SUNPAR110", aniline point: 104.3°C, kinematic viscosity (100°C): 4.2 mm ２ / s, %CP: 67%); M'2 is a naphthenic hydrocarbon solvent (manufactured by Japan Sun Oil Co., 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 Kraton Polymers Co., Ltd., trade name "Kraton G1651"); and N2 represents a styrene-ethylene-propylene-styrene (SEPS) block copolymer (manufactured by Kuraray Co., Ltd., trade name "Septon 2006").

[0046] The thermoplastic resin compositions of Examples 1 to 8 obtained evaluation results that satisfied the target values ​​for noise reduction characteristics and low-temperature impact resistance.

[0047] In Comparative Example 1, the aniline point of the paraffinic hydrocarbon solvent (M'1) was low, and therefore the low-temperature impact resistance was poor.

[0048] Comparative Example 2 contained a naphthenic hydrocarbon solvent (M'2) with a low aniline point instead of the paraffinic hydrocarbon solvent (M), and therefore had poor low-temperature impact resistance.

[0049] Comparative Example 3 did not contain the styrene elastomer (N), and therefore was inferior in noise reduction properties.

[0050] Comparative Example 4 did not contain the paraffinic hydrocarbon solvent (M), and therefore had poor low-temperature impact resistance.

Claims

1. A thermoplastic resin composition comprising a thermoplastic resin (L), a paraffinic hydrocarbon solvent (M), and a styrene-based elastomer (N), wherein the thermoplastic resin (L) is one or more selected from the group consisting of polycarbonate resins, and resins having rubber polymers, vinyl cyanide monomers, and aromatic vinyl monomers as structural units, the paraffinic hydrocarbon solvent (M) has an aniline point of 110°C or higher, and the styrene-based elastomer (N) is a block copolymer including a polymer block having polystyrene and a polymer block having a conjugated diene compound.

2. The thermoplastic resin composition according to claim 1, characterized in that the ratio of said paraffinic hydrocarbon solvent (M) is 1.5 to 8.0 parts by weight, the ratio of said styrene-based elastomer (N) is 1.0 to 6.0 parts by weight, and the weight ratio of said paraffinic hydrocarbon solvent (M) to said styrene-based elastomer (N) ((M) / (N)) is 1 or more, relative to 100 parts by weight of said thermoplastic resin (L).

3. A thermoplastic resin molded article obtained from the thermoplastic resin composition according to claim 1 or 2.

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