JP2023019031A - Thermoplastic resin composition and molded article - Google Patents

Abstract

To provide a thermoplastic resin composition which is excellent in mechanical strength, flowability and quietness, especially, impact strength and durability of quietness when exposed at high temperatures for a long time, and a molded article of the same.SOLUTION: There are provided a thermoplastic resin composition which is obtained by blending 1-5 pts.wt. of an α-olefin oligomer and/or a cooligomer of ethylene and α-olefin (C) with 100 pts.wt. of a thermoplastic resin composition containing 10-50 pts.wt. of a styrene resin (A) and 50-90 pts.wt. of a polycarbonate resin (B) when the total of the styrene resin (A) and the polycarbonate resin (B) is 100 pts.wt, and has kinetic viscosity at 100°C of the component (C) of 30 cSt or more; and a molded article of the same.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition excellent in mechanical strength, fluidity and quietness (squeak noise suppressing effect), and a resin molded product.

A polymer alloy obtained by blending ABS resin and polycarbonate (PC) resin obtained by polymerizing diene rubber polymer, aromatic vinyl monomer, vinyl cyanide monomer, methacrylic acid ester monomer, etc. is excellent in impact resistance, moldability, appearance, etc., and is widely used in various applications such as automobile parts, OA equipment, home appliances, game machine parts, and general miscellaneous goods.

2. Description of the Related Art In recent years, parts to be installed in automobiles, such as console panels, dashboards, car navigation systems, air conditioners, and the like, are manufactured by fitting and assembling molded resin parts for the purpose of weight reduction. For example, in the case of a housing structure, generally, fitting parts for fitting are integrally formed in upper and lower halves of a container-shaped molded part, respectively, and screws are hardly used or used to a minimum. A housing molded product is manufactured by fastening and fitting the outer peripheral edges of the upper and lower molded parts.

On the other hand, conventionally reported techniques for improving slidability include a method of blending an α-olefin oligomer and/or a co-oligomer of ethylene and α-olefin with a resin composition composed of an ABS resin (see Patent Document 1). A method of blending an α-olefin lubricating oil with a polyacetal resin has been reported (see Patent Document 2). In addition, as a conventionally reported technique for improving quietness, a method of blending an ethylene-vinyl acetate copolymer into a resin composition composed of a PC resin and an ABS resin (see Patent Document 3), a PC resin and an ABS resin. A method of blending an ethylene-vinyl acetate copolymer and oxidized polyethylene wax with a resin composition consisting of (see Patent Document 4), and the like have been proposed.

JP-A-10-204252 JP-A-2005-29713 JP 2019-199602 A JP 2018-141078 A

When a housing molded product obtained by fitting the outer peripheral edges of upper and lower molded parts is mounted on a vehicle, the temperature in the automobile interior changes rapidly from low to high, and the resin molded product shrinks and expands due to thermal fluctuations, causing deformation. If there is even a slight deformation in the fitting portion, a squeaking sound is likely to occur due to vibration or the like during driving of the automobile. The squeaky noise greatly impairs the comfort of riding, and in particular, the more expensive the vehicle, the higher the interior quietness is required, and the prevention of the squeaky noise is an extremely important issue. Such squeaking noise occurs when the members are rubbed against each other. As an effective means for preventing and reducing the squeak, the surface of the molded product is coated with grease or fluororesin. However, this method is difficult to automate and has to rely on manual work, and the effect does not last, so it is not a permanent countermeasure, and a technology that imparts quietness (prevents squeaking noise) to the resin is required. It is

In addition, in recent years, the thickness of these resin molded products has been reduced in order to reduce the weight. Techniques have been developed to improve

As a method to improve quietness, applying grease or attaching non-woven fabric to parts has been done, but there are problems such as the generation of volatile organic compounds (VOC) from the manufacturing process of parts and products after assembly. However, it is difficult to automate the process, which raises the manufacturing cost of the product.

The conventionally proposed methods for imparting quietness to thermoplastic resin compositions are not sufficient in terms of the required high degree of quietness, its durability, and mechanical properties, and further improvements are required. .

Accordingly, an object of the present invention is to solve the problems of the prior art, and provide a thermoplastic resin composition which is excellent in mechanical strength, fluidity, and quietness, especially impact strength and durability of quietness when exposed to high temperatures for a long time. It is to provide a product and its molded product.

As a result of intensive studies to solve such problems, it was found that a thermoplastic resin composition containing an α-olefin oligomer and/or a co-oligomer of ethylene and α-olefin having a specific kinematic viscosity was blended. The present inventors have found that a resin composition and a molded article thereof having excellent mechanical strength, fluidity, and quietness can be obtained, and have completed the present invention.

That is, the present invention has the following configurations.
(1) Thermoplastic resin containing 10 to 50 parts by weight of styrene resin (A) and 50 to 90 parts by weight of polycarbonate resin (B), with the total of styrene resin (A) and polycarbonate resin (B) being 100 parts by weight 1 to 5 parts by weight of an α-olefin oligomer and/or a co-oligomer of ethylene and an α-olefin (C) is blended with 100 parts by weight of the composition, and the kinematic viscosity of the component (C) at 100° C. is 30 cSt or more. A thermoplastic resin composition characterized by being
(2) The thermoplastic resin composition according to (1), which contains 1 to 3 parts by weight of component (C) with the total of styrene resin (A) and polycarbonate resin (B) being 100 parts by weight.
(3) 100 parts by weight of the total of the styrene resin (A) and the polycarbonate resin (B), and 1 to 5 parts by weight of an ethylene-vinyl acetate copolymer (D) having a styrene (co)polymer segment. The thermoplastic resin composition according to (1) or (2), which is blended with.
(4) The thermoplastic resin composition according to (3), which contains 1 to 3 parts by weight of component (D) with the total of styrene resin (A) and polycarbonate resin (B) being 100 parts by weight.
(5) A molded article made of the thermoplastic resin composition according to any one of (1) to (4).

INDUSTRIAL APPLICABILITY According to the present invention, a thermoplastic resin composition having excellent mechanical strength, fluidity, and quietness can be obtained, which can be used for automobile parts, OA equipment, home electric appliances, general miscellaneous goods, and the like.

The present invention will be described in detail below along with embodiments.
The thermoplastic resin composition of the present invention comprises 10 to 50 parts by weight of the styrene resin (A) and 50 to 90 parts by weight of the polycarbonate resin (B), with the total of the styrene resin (A) and the polycarbonate resin (B) being 100 parts by weight. 100 parts by weight of a thermoplastic resin composition containing kinematic viscosity (measured according to JIS K2833 (2000)) of 30 cSt or more.

The styrenic resin (A) used in the present invention is composed of a polymer containing an aromatic vinyl monomer as its component. Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, t-butylstyrene, o-ethylstyrene, o-chlorostyrene and o,p-dichlorostyrene. Among them, styrene and α-methylstyrene are preferably used. Aromatic vinyl monomers may be used alone or in combination of two or more.

In addition, the styrene-based resin (A) is an aromatic vinyl-based monomer and other vinyl-based monomers copolymerizable with the aromatic vinyl-based monomer for the purpose of imparting properties such as chemical resistance and heat resistance. It may contain a vinyl copolymer obtained by copolymerizing monomers. Examples of these other vinyl monomers include acrylonitrile, methacrylonitrile, ethacrylonitrile, (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, (meth)acrylic acid n -propyl, n-butyl (meth)acrylate, t-butyl (meth)acrylate, n-hexyl (meth)acrylate, glycidyl (meth)acrylate, allyl glycidyl ether, styrene-p-glycidyl ether, p- Glycidylstyrene 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2,3,4,5,6-pentahydroxyhexyl (meth)acrylate, 2,3,4,5 acrylic acid - tetrahydroxypentyl, maleic acid, maleic anhydride, maleic acid monoethyl ester, itaconic acid, itaconic anhydride, phthalic acid, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, acrylamide, Methacrylamide, N-methylacrylamide, butoxymethylacrylamide, N-propylmethacrylamide, aminoethyl acrylate, propylaminoethyl acrylate, dimethylaminoethyl methacrylate, ethylaminopropyl methacrylate, phenylaminoethyl methacrylate, cyclohexyl methacrylate aminoethyl, N-vinyldiethylamine, N-acetylvinylamine, allylamine, methallylamine, N-methylallylamine, p-aminostyrene, 2-isopropenyl-oxazoline, 2-vinyl-oxazoline, 2-acryloyl-oxazoline, and 2 -styryl-oxazoline and the like. Among these, acrylonitrile and methyl methacrylate are particularly preferably used.

The proportion of the aromatic vinyl monomer contained in the styrene resin (A) is preferably 10 to 100 parts by weight, more preferably 20 to 90 parts by weight, from the viewpoint of moldability.

The polystyrene-equivalent weight-average molecular weight of the styrene-based resin (A) is preferably 50,000 to 300,000 in order to maintain a balance of physical properties. The weight average molecular weight can be measured by a generally known method using gel permeation chromatography (GPC).

The method for producing the styrene-based resin (A) is not particularly limited, and conventional production methods such as bulk polymerization, suspension polymerization, emulsion polymerization and bulk-suspension polymerization can be used. Alternatively, one or more styrene-based resins obtained by any of these methods may be melt-kneaded for production.

When the purpose is to dramatically improve the properties such as impact resistance of the styrene resin (A), a rubbery material is added as the styrene resin in a matrix composed of an aromatic vinyl-based (co)polymer. It is preferable to use a rubber-modified styrenic resin in which a polymer is dispersed. That is, a graft obtained by graft-polymerizing an aromatic vinyl-based monomer and another vinyl-based monomer copolymerizable with the aromatic vinyl-based monomer to a rubber-like polymer as a styrene-based resin. A rubber-modified styrenic resin containing a copolymer can be preferably used. Further, an aromatic vinyl-based monomer, a vinyl-based copolymer obtained by copolymerizing another vinyl-based monomer copolymerizable with the aromatic vinyl-based monomer, and a rubber-like polymer may contain an aromatic A rubber-modified styrenic resin containing a vinyl-based monomer and a graft copolymer obtained by graft-polymerizing another vinyl-based monomer copolymerizable with the aromatic vinyl-based monomer is also preferred. can be used.

In the present invention, the (co)polymer means a polymer and/or a copolymer as described above.

Examples of rubbery polymers include diene rubbers such as polybutadiene, styrene-butadiene copolymers, acrylonitrile-butadiene copolymers, styrene-butadiene block copolymers, and butyl acrylate-butadiene copolymers; Examples include acrylic rubbers such as butyl acid, polyisoprene, and ethylene-propylene-diene terpolymers, among which polybutadiene and butadiene copolymers are preferably used.

From the viewpoint of excellent impact resistance, the rubbery polymer is preferably rubber particles having an average particle size of 0.15 to 0.60 μm, and rubber particles having an average particle size of 0.2 to 0.55 μm. is more preferred. Among them, since the impact resistance and the falling weight impact of thin-walled molded products are remarkably excellent, rubber particles having an average particle size in the range of 0.20 to 0.25 μm and rubber particles having an average particle size in the range of 0.50 to 0.65 μm A rubbery polymer having a weight ratio to the particles of 90:10 to 60:40 is particularly preferred.

Here, the average weight particle size of the rubber particles is the cumulative sodium alginate concentration described in "Rubber Age, Vol.88, p.484-490, (1960), by E. Schmidt, P.H. Biddison". It can be measured by a method of determining the particle diameter at a cumulative weight fraction of 50% from the weight fraction.

When the above rubber-modified styrene resin is used as the styrene resin (A), the rubber polymer is incompatible with the matrix styrene resin, so the rubber polymer is compatible with the matrix. The impact resistance can be further improved by graft-polymerizing the component to be used. That is, it is preferable to use a graft copolymer obtained by graft-polymerizing an aromatic vinyl-based monomer or a mixture of monomers to a rubber-like polymer. As the monomers used for graft polymerization, it is preferable to use monomer components similar to those in the aromatic vinyl-based (co)polymer, which is the matrix, in the same proportions.

The composition and the amount of grafting are preferably adjusted so as not to impair the dispersibility of the rubbery polymer. The graft ratio is preferably 5-200%, more preferably 20-100%. The graft rate referred to here is a value calculated by the following formula.
Grafting ratio = amount of vinyl copolymer graft-polymerized to rubbery polymer/rubber content of graft copolymer x 100

Regarding the properties of the (co)polymer that is not graft-polymerized, from the viewpoint of obtaining a resin composition having excellent impact resistance, the intrinsic viscosity [η] of the methyl ethyl ketone soluble component (measured at 30°C) is It is preferably in the range of 0.25 to 0.60 dl/g, more preferably in the range of 0.25 to 0.50 dl/g.

As a method for producing a rubber-modified styrenic resin, specifically, a graft copolymer obtained by graft-polymerizing a monomer or a mixture of monomers containing an aromatic vinyl-based monomer to a rubbery polymer. A method of producing a rubber-modified styrenic resin by melt-kneading a coalescence and a styrenic (co)polymer obtained by polymerizing a monomer or a mixture of monomers containing an aromatic vinyl monomer. , industrially and economically.

The graft copolymer contained in the rubber-modified styrenic resin can be obtained by known polymerization methods such as emulsion polymerization and bulk polymerization. Among them, a method of continuously supplying a monomer or a mixture of a monomer mixture, a radical generator and a chain transfer agent in the presence of a rubbery polymer latex to a polymerization vessel for emulsion polymerization is suitable for operation. is.

Specific examples of the styrene resin (A) used in the present invention include polystyrene, high impact polystyrene, AS resin, AAS resin, AES resin, ABS resin, MAS resin, MS resin, MABS resin and MBS resin. There are also alloys of these resins and other resins.

The mixing ratio of the styrene resin (A) used in the present invention is 10 to 50 parts by weight of the styrene resin (A), with the total of the styrene resin (A) and the polycarbonate resin (B) being 100 parts by weight. but more preferably 25 to 50 parts by weight. If the styrenic resin (A) is less than 10 parts by weight, the proportion of the polycarbonate resin (B) will be too high and the fluidity will tend to be poor. When the styrene-based resin (A) exceeds 50 parts by weight, the proportion of the polycarbonate resin (B) tends to decrease, resulting in poor impact resistance.

As the polycarbonate resin (B) used in the present invention, aromatic polycarbonate resins, aliphatic polycarbonate resins, aliphatic-aromatic polycarbonate resins, and the like can be suitably used. A mixture of the above may be used. Aromatic polycarbonate resins, which are excellent in balance of mechanical properties, are particularly preferably used.

Examples of the aromatic polycarbonate resin include those having a bisphenol A skeleton, as well as those having a bisphenol S skeleton.

Commercial products of the polycarbonate resin (B) include polycarbonate resin "Panlite" (registered trademark) 1250WP manufactured by Teijin Chemicals Co., Ltd. and polycarbonate resin "Taflon" (registered trademark) A2200, FN2200, A1900 manufactured by Idemitsu Kosan Co., Ltd. etc.

The method for producing the polycarbonate resin (B) is not particularly limited, and known methods can be used. For example, in the production of polycarbonate of 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A), 2,2-bis(4-hydroxyphenyl)propane is used as the dioxy compound, and caustic aqueous solution and A phosgene method in which phosgene is blown into the presence of a solvent for production, or the like can be used.

The polycarbonate resin (B) preferably has a viscosity average molecular weight in the range of 10,000 to 40,000, particularly 15,000 to 30,000. If the viscosity-average molecular weight is less than 10,000, mechanical properties tend to deteriorate, and if the viscosity-average molecular weight exceeds 40,000, moldability tends to deteriorate.

The viscosity average molecular weight (Mv) of the polycarbonate resin (B) can be determined by measuring the intrinsic viscosity (intrinsic viscosity) in methylene chloride at 20° C. and using the following Mark-Houwink viscosity formula.
Intrinsic viscosity [η] = K (Mv) a
(wherein K=1.23×10 ⁻⁴ , a=0.83)

Monomers used in the α-olefin oligomer and/or co-oligomer (C) of ethylene and α-olefin used in the present invention include ethylene and an α-olefin having 3 to 20 carbon atoms such as propylene and 1-butene. , 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like.

α-Olefin oligomers and/or co-oligomers (C) of ethylene and α-olefin are commercially available, for example, they are obtained by selecting from the trade name “Lucant (registered trademark)” series manufactured by Mitsui Chemicals, Inc. be able to.

The α-olefin oligomer and/or co-oligomer (C) of ethylene and α-olefin used in the present invention preferably has a kinematic viscosity of 30 to 1000 cSt at 100° C. from the viewpoint of quietness and productivity. If the kinematic viscosity at 100°C is less than 30 cSt, sufficient quietness tends not to be obtained, and if the kinematic viscosity at 100°C exceeds 1000 cSt, the productivity tends to decrease when mixing the resin composition. . The kinematic viscosity value at 100° C. can be measured for each α-olefin oligomer and/or co-oligomer (C) of ethylene and α-olefin used in the present invention. If you use the products of the product name "Lucant (registered trademark)" series manufactured by the company, the kinematic viscosity value at 100°C is specified as a catalog value for each product.

The thermoplastic resin composition according to the present invention may further contain an α-olefin oligomer and/or a co-oligomer (C) of ethylene and α-olefin. The content of the α-olefin oligomer and/or the co-oligomer (C) of ethylene and α-olefin used in the present invention is 1 to 1, with the total of the styrene resin (A) and the polycarbonate resin (B) being 100 parts by weight. 5 parts by weight, more preferably 1 to 4 parts by weight, even more preferably 1 to 3 parts by weight. If the blending amount is less than 1 part by weight, there is a tendency that sufficient quietness cannot be obtained. tend to get worse.

The ethylene-vinyl acetate copolymer (D) having a styrene-based (co)polymer segment used in the present invention comprises a styrene-based (co)polymer segment (segment) and an ethylene-vinyl acetate copolymer segment (segment). Although there is no limitation as long as it is a copolymer consisting of Graft copolymers having coalescence as a main chain and styrenic (co)polymer segments as side chains are preferred.

The proportion of vinyl acetate units in the ethylene-vinyl acetate copolymer is preferably 1 to 20% by mass, more preferably 3 to 10% by mass.

The styrenic (co)polymer segment is a homopolymer of a styrenic monomer or a copolymer with another vinylic monomer. Styrenic monomers include, for example, styrene, methylstyrene, dimethylstyrene, ethylstyrene, isopropylstyrene, and chlorostyrene, with styrene being particularly preferred. Other vinyl monomers preferably include vinyl cyanide monomers; glycidyl esters of acrylic acid or methacrylic acid; and alkyl esters of acrylic acid or methacrylic acid. Examples of vinyl cyanide monomers include acrylonitrile and methacrylonitrile, and acrylonitrile is particularly preferred. Examples of glycidyl esters of acrylic acid or methacrylic acid include glycidyl acrylate and glycidyl methacrylate, with glycidyl methacrylate being preferred. The alkyl ester of acrylic acid or methacrylic acid is preferably an alkyl ester having 1 to 8 carbon atoms, such as methyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, Examples include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate and isobutyl methacrylate. As other vinyl monomers, among the above, glycidyl esters of acrylic acid or methacrylic acid and vinyl cyanide monomers are preferred, glycidyl esters of acrylic acid or methacrylic acid are more preferred, and glycidyl methacrylic acid is particularly preferred. preferable.

The content of the styrene-based monomer and the other vinyl-based monomer in the styrene-based (co)polymer segment is not particularly limited, but the total amount of the styrene-based monomer and the other vinyl-based monomer is 100 parts by mass. On a standard basis, the content of the styrene-based monomer is preferably 50-100 parts by mass. Further, the content of the styrene-based (co)polymer segment is 10 to 50 parts by mass when the entire ethylene-vinyl acetate copolymer (D) is 100% by mass. is preferably

The ethylene-vinyl acetate copolymer (D) having a styrenic (co)polymer segment can be produced by various known methods. A preferred method is to add a styrene-based monomer or other vinyl-based monomer and a radically polymerizable organic peroxide to an aqueous suspension of an ethylene-vinyl acetate copolymer with a suspending agent added. are mixed, heated and stirred to impregnate the ethylene-vinyl acetate copolymer with the above components, and then the temperature is raised to polymerize.

In addition, the ethylene-vinyl acetate copolymer (D) having a styrenic (co)polymer segment is commercially available. can be obtained by

The content of the ethylene-vinyl acetate copolymer (D) having a styrene-based (co)polymer segment is 1 to 5 parts by weight, with the total of the styrene-based resin (A) and the polycarbonate resin (B) being 100 parts by weight. is preferred, 1 to 4 parts by weight is more preferred, and 1 to 3 parts by weight is even more preferred. If the content is less than 1 part by weight, the effect of suppressing the squeak noise tends to decrease.

The method for producing the thermoplastic resin composition of the present invention is not particularly limited. For example, it can be produced by melt-kneading with a Banbury mixer, rolls, extruder, kneader, or the like, but from the viewpoint of dispersibility of the ingredients. It is preferable to use a twin-screw extruder. The temperature during melt-kneading is usually about 200 to 300° C., depending on the ingredients.

Molding methods for molded articles made of the thermoplastic resin composition of the present invention can be molded by known methods such as injection molding, extrusion molding, blow molding, vacuum molding, compression molding, and gas-assisted molding, and are not particularly limited. It is preferably molded by injection molding, although not necessarily. The injection molding temperature is preferably 230° C. to 300° C. from the viewpoint of molding processability.

Various thermoplastic resin compositions may be added to the thermoplastic resin composition of the present invention as long as the object of the present invention is not impaired. For example, polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, polyamide resins such as nylon 6 and nylon 6,6, modified PPE resins, polyacetal resins, modified products thereof, and polylactic acid The performance of the molded article can be further improved by blending a plant-derived resin such as Elastomer.

The thermoplastic resin composition of the present invention contains antioxidants such as hindered phenols, sulfur-containing organic compounds, and phosphorus-containing organic compounds, and thermal additives such as phenols and acrylates, as long as the effects of the present invention are not impaired. Stabilizers, benzotriazole-based, benzophenone-based, salicylate-based UV absorbers, various stabilizers such as organic nickel-based, hindered amine-based light stabilizers, metal salts of higher fatty acids, lubricants such as higher fatty acid amides, phthalate Plasticizers such as acid esters and phosphate esters, halogen-containing compounds such as polybrominated diphenyl ether, tetrabromobisphenol-A, brominated epoxy oligomers and brominated polycarbonate oligomers, phosphorus compounds, flame retardants such as antimony trioxide • Liquids such as flame retardant aids, antistatic agents, carbon black, titanium oxide, pigments and dyes, water, and liquid paraffin can also be added. Furthermore, reinforcing agents and fillers such as glass fibers, glass flakes, glass beads, carbon fibers and metal fibers can be added. The method of adding these additives is not particularly limited, and various methods can be used.

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

(1) Grafting Ratio To a predetermined amount (m; about 1 gram) of the obtained graft copolymer, 200 ml of acetone was added and refluxed in a hot water bath at 70°C for 3 hours. p. After centrifugation at 10,000 G for 40 minutes, the insoluble matter was filtered. The obtained acetone-insoluble matter was dried under reduced pressure at 60° C. for 5 hours, and its mass (m; unit gram) was measured. The graft ratio was calculated from the following formula. Here, L is the rubber content of the graft copolymer (a real number greater than 0 and less than 1).
Graft rate (% by mass) = {[(n)-{(m) x L}]/[(m) x L]} x 100

(2) Weight average molecular weight The weight average molecular weight of the methyl ethyl ketone soluble portion of the obtained vinyl copolymer was measured using a gel permeation chromatography (GPC) device manufactured by Water, using a differential refractometer as a detector (Water 2414). , Polymer Laboratories Co., Ltd. MIXED-B (2 columns), distillate tetrahydrofuran, flow rate 1 ml/min, column temperature 40°C.

(3) Reduced Viscosity 200 ml of acetone was added to 1 g of the sample, refluxed for 3 hours, centrifuged at 8800 r/min (1000 G) for 40 minutes, and filtered to remove unnecessary components. The filtrate was concentrated with a rotary evaporator, and the precipitate was dried under reduced pressure at a temperature of 60°C for 5 hours.

(4) MFR (melt flow rate)
MFR was measured under conditions of 240° C. and 98 N in accordance with ISO1133:2011.

(5) Impact resistance The pellets obtained in each example and comparative example were dried in a hot air dryer at a temperature of 105°C for 3 hours, and the injection was performed by setting the cylinder temperature to 250°C and the mold temperature to 60°C. Using a molding machine, a multi-purpose test piece type A1 specified in JIS K 7139: 2009 is molded, and a type B2 test piece cut from this is used to measure the Charpy impact strength in accordance with ISO179: 2010/1eA. bottom.

(6) Flexural modulus The pellets obtained in each example and comparative example were dried in a hot air dryer at a temperature of 105°C for 3 hours, and injection was performed by setting the cylinder temperature to 250°C and the mold temperature to 60°C. Using a molding machine, a multi-purpose test piece type A1 defined in JIS K 7139:2009 was molded, and a type B2 test piece cut from this was used to measure the flexural modulus in accordance with ISO178.

(7) HDT (load deflection temperature)
The pellets obtained in each example and comparative example were dried in a hot air dryer at a temperature of 105°C for 3 hours, and an injection molding machine was used in which the cylinder temperature was set to 250°C and the mold temperature was set to 60°C. A multi-purpose test piece type A1 defined in JIS K 7139:2009 was molded, and a type B2 test piece cut from this was used to measure the load deflection temperature under a load of 1.80 MPa in accordance with ISO75.

(8) Quietness The pellets obtained in each example and comparative example were dried in a hot air dryer at a temperature of 105 ° C for 3 hours, and the cylinder temperature was set to 250 ° C and the mold temperature was set to 60 ° C. Injection molding. Using a machine, 50 mm (length) x 25 mm (width) x 2 mmt (thickness) test pieces and 80 mm x 80 mm x 2 mmt test pieces were molded. A test piece of 50 mm×25 mm×2 mmt was deburred after molding.

Quietness is evaluated by rubbing the two types of test pieces described above using a stick-slip measuring device SSP-04 manufactured by Ziegler under the conditions of a 40N load and a speed of 1 mm / s. The noise risk value when rubbing against each other at a speed of 20 mm/s was measured and evaluated as initial quietness. Note that the smaller the abnormal noise risk value, the smaller the risk of generating squeaking noise, and the criteria for determination are as follows.
Abnormal noise risk values 1 to 3: Low risk of squeak noise Risk values 4 to 5: Slightly high risk of squeak noise Risk values 6 to 10: High risk of squeak noise occurrence.

Furthermore, as a test assuming aging of the resin molded body, the above two types of quietness evaluation test specimens were left standing in a hot air dryer at 80 ° C. for 500 hours, followed by a constant temperature of 23 ° C. x 50% RH. After standing in the tank for 24 hours, the abnormal noise risk value was measured. This was used to evaluate the durability of quietness.

(9) Mold contamination The pellets obtained in each example and comparative example were dried in a hot air dryer at a temperature of 105 ° C. for 3 hours, and the cylinder temperature was set to 300 ° C. and the mold temperature was set to 60 ° C. Using an injection molding machine, a multi-purpose test piece type A1 specified in JIS K 7139:2009 was continuously molded 1000 times. The staining property of the mold was evaluated by visually observing the stain of the mold after molding. Judgment criteria are as follows.
○: No cloudiness observed on the mold design surface ×: Cloudiness observed on the mold design surface

(10) Appearance (9) Appearance was evaluated by visually observing the appearance of 1,000 molded products molded in mold contamination evaluation. Judgment criteria are as follows. ○ to △ was regarded as a pass.
○: The percentage of molded products with appearance defects is less than 1% △: The percentage of molded products with appearance defects is 1% or more and less than 5% ×: The percentage of molded products with appearance defects is 5 % or more

(Reference Example 1) Preparation of styrenic resin Preparation of graft copolymer (A-1) Into a reactor purged with nitrogen, 120 parts by weight of pure water, 0.5 parts by weight of glucose, 0.5 parts by weight of sodium pyrophosphate, 0.005 parts by weight of ferrous sulfide and 60 parts by weight of polybutadiene latex (weight average particle size: 0.3 μm, gel content: 85%) were charged, and the temperature in the reactor was raised to 65° C. while stirring. heated up. Polymerization was initiated when the internal temperature reached 65° C., and a mixture of monomers (30 parts by weight of styrene and 10 parts by weight of acrylonitrile) and 0.3 parts by weight of t-dodecylmercaptan was continuously added dropwise over 5 hours. At the same time, an aqueous solution consisting of 0.25 parts by weight of cumene hydroperoxide, 2.5 parts by weight of potassium oleate and 25 parts by weight of pure water was continuously added dropwise over 7 hours to complete the reaction. The obtained styrenic copolymer latex was coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered and dried to obtain a graft copolymer A-1. The graft ratio of this styrene-based graft copolymer A-1 was 35%, and the reduced viscosity of the resin component was 0.35 dl/g.

(Reference Example 2) Preparation of vinyl copolymer (A-2) A slurry obtained by suspension polymerization of a monomer mixture consisting of 72% by weight of styrene and 28% by weight of acrylonitrile was washed, dewatered and dried. After that, a vinyl copolymer A-2 was prepared. The weight-average molecular weight of the resulting vinyl copolymer A-2 was 100,000.

(Reference Example 3) Polycarbonate resin (B-1)
"Iupilon (registered trademark)" S-2000 (viscosity average molecular weight 23,000) manufactured by Mitsubishi Engineering-Plastics was used.

(Reference Example 4) α-olefin oligomer and/or co-oligomer of ethylene and α-olefin (C-1): “Lucant (registered trademark)” HC-10 manufactured by Mitsui Chemicals, Inc. (kinematic viscosity at 100°C: 10 cSt)
(C-2): Mitsui Chemicals, Inc. “Lucant (registered trademark)” HC-20 (kinematic viscosity at 100 ° C. 20 cSt)
(C-3): Mitsui Chemicals, Inc. “Lucant (registered trademark)” HC-40 (kinematic viscosity at 100 ° C. 40 cSt)
(C-4): Mitsui Chemicals, Inc. “Lucant (registered trademark)” HC-600 (kinematic viscosity at 100 ° C. 600 cSt)
were used respectively.

(Reference Example 5) Ethylene-vinyl acetate copolymer (D-1) having a styrenic (co)polymer segment
NOF's "Modiper (registered trademark)" AS-100 (a graft copolymer having an ethylene-vinyl acetate copolymer as a main chain and a styrene polymer side chain) was used.

(Examples 1 to 6, Comparative Examples 1 to 9)
Styrenic resins (A-1) to (A-2), polycarbonate resins (B-1), oligomers (C-1) to (C-4), and copolymers ( D-1) were each compounded at the compounding ratio shown in Table 1, mixed with a Henschel mixer at 23 ° C., and then the resulting mixture was extruded in a co-rotating twin-screw extruder with a screw diameter of 30 mm (temperature range: 240 to 260° C.) to obtain pellets. The obtained pellets were evaluated by the method described above.

The thermoplastic resin composition of the present invention is excellent in mechanical strength, fluidity, and quietness, especially impact strength and durability of quietness when exposed to high temperatures for a long time. It can be suitably used for molded articles, especially automobile parts, as well as OA equipment, home electric appliances, and general miscellaneous goods.

Claims (5)

A thermoplastic resin composition 100 containing 10 to 50 parts by weight of the styrene resin (A) and 50 to 90 parts by weight of the polycarbonate resin (B), where the total of the styrene resin (A) and the polycarbonate resin (B) is 100 parts by weight. 1 to 5 parts by weight of an α-olefin oligomer and/or a co-oligomer of ethylene and an α-olefin (C) is blended in parts by weight, and the kinematic viscosity of the component (C) at 100° C. is 30 cSt or more. A thermoplastic resin composition characterized by: The thermoplastic resin composition according to claim 1, comprising 1 to 3 parts by weight of component (C), with the total of styrene resin (A) and polycarbonate resin (B) being 100 parts by weight. The total of styrene resin (A) and polycarbonate resin (B) is 100 parts by weight, and 1 to 5 parts by weight of ethylene-vinyl acetate copolymer (D) having a styrene (co)polymer segment is blended. The thermoplastic resin composition according to claim 1 or 2, comprising: The thermoplastic resin composition according to claim 3, comprising 1 to 3 parts by weight of component (D), with the total of styrene resin (A) and polycarbonate resin (B) being 100 parts by weight. A molded article made of the thermoplastic resin composition according to any one of claims 1 to 4.