Thermoplastic resin composition and molded article

Abstract

To provide a thermoplastic resin composition that has high sliding properties, maintains those sliding properties over time, has excellent scratch resistance, and can also retain mechanical properties such as impact resistance and rigidity, as well as moldability, and a molded article obtained from the thermoplastic resin composition. [Solution] The problem is solved by a thermoplastic resin composition comprising a thermoplastic resin (A), an organopolysiloxane (B) satisfying the following conditions (1) and (2), and silica (C). (1) The number-average molecular weight (Mn) is between 150,000 and 500,000, the weight-average molecular weight (Mw) is between 200,000 and 1,000,000, and the ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn) is between 1.0 and 3.0. (2) The loss tangent (tanδ) in dynamic viscoelasticity measurements at 25°C, 1% strain, and a frequency of 0.1 rad / sec is 1 or greater.

Description

[Technical Field]

[0001] The present invention relates to thermoplastic resin compositions and molded articles. [Background technology]

[0002] Because plastics are easy to mold and process, they are used in a wide range of fields, including electrical and electronic equipment components, automotive parts, medical components, and food containers. There is a lot of research being done on plastic molded products to enhance their decorative properties or add functionality. In particular, there is a demand for resin molded products that possess both mechanical properties and sliding properties in a wide range of fields, including automobiles, home appliances, and office automation equipment. Sliding properties, also known as lubricity, are required for sliding parts such as gears and bearings, electrical and electronic equipment such as printer feeders, agricultural materials such as agricultural sheets, and building components such as fixed-fit support materials. Furthermore, with the shift towards electric vehicles and the increasing performance of home appliances, it is necessary to combine and work together multiple more complex components than before. Therefore, high sliding properties are required for the parts used in areas where these components rub against each other.

[0003] As thermoplastic resin compositions for forming such sliding parts, Patent Document 1 discloses a thermoplastic resin composition using acrylonitrile-butadiene-styrene (ABS) resin, low viscosity silicone oil, and a flame retardant; Patent Document 2 discloses a thermoplastic resin composition using special acrylonitrile-ethylene-propylene-diene-styrene resin (AES) or acrylonitrile-butadiene-styrene resin (ABS) and low viscosity silicone oil; and Patent Document 3 discloses a thermoplastic resin composition using polyacetal resin (POM) and cellulose fibers. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 2798396 [Patent Document 2] Patent No. 6486884 [Patent Document 3] Japanese Patent Publication No. 2024-6720 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the sliding performance achieved by these methods is not entirely satisfactory. While some degree of sliding ability is observed immediately after molding, the effect does not last long. Furthermore, there are challenges in achieving both sliding properties and mechanical properties such as formability and tensile elongation.

[0006] For example, as in Patent Document 1, when ABS resin, low-viscosity silicone oil, and a flame retardant are used, the low-viscosity silicone oil has a small molecular weight and is easily exposed on the surface, so it is possible to achieve a certain degree of both sliding properties and flame retardancy. However, the silicone oil is lost over time, resulting in poor durability, and mechanical properties such as elastic modulus and elongation also deteriorate. As in Patent Document 2, using special acrylonitrile-ethylene-propylene-diene-styrene resin (AES) or acrylonitrile-butadiene-styrene resin (ABS) with low-viscosity silicone oil improves the durability of sliding properties somewhat, but the amount of silicone oil that can be contained is small, so the level of sliding properties is insufficient to begin with. Patent Document 3 uses cellulose fibers instead of silicone oil, which allows for sliding properties while maintaining the flexural modulus, but the level of sliding properties is insufficient, and the tensile elongation decreases.

[0007] High lubricity can be achieved by adding a large amount of lubricant, such as silicone oil. However, lubricants generally need to appear on the surface of the parts that require lubricity, and to achieve this, lubricants that are poorly compatible with the thermoplastic resin used as the main component are often used. While high lubricity can be achieved by including a large amount of such lubricant, problems arise during molding, such as cracking and silvering, and scratches become more noticeable on the molded product.

[0008] Therefore, the present invention aims to provide a thermoplastic resin composition that has high sliding properties, maintains those sliding properties over time, has excellent scratch resistance, and can also maintain mechanical properties such as impact resistance and rigidity, as well as moldability, and a molded article obtained from the thermoplastic resin composition. The objective is to provide a thermoplastic resin composition that can be suitably used, in particular, for sliding parts. [Means for solving the problem]

[0009] In other words, the present invention includes the following embodiments. The embodiments of the present invention are not limited to the following. [1] A thermoplastic resin composition comprising a thermoplastic resin (A), an organopolysiloxane (B) satisfying the following conditions (1) and (2), and silica (C). (1) The number-average molecular weight (Mn) is between 150,000 and 500,000, the weight-average molecular weight (Mw) is between 200,000 and 1,000,000, and the ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn) is between 1.0 and 3.0. (2) The loss tangent (tanδ) in dynamic viscoelasticity measurements at 25°C, 1% strain, and a frequency of 0.1 rad / sec is 1 or greater. [2]: The thermoplastic resin composition according to [1], wherein the content ratio (C) / (B) of organopolysiloxane (B) to silica (C) is 0.10 to 0.67. [3]: The BET specific surface area of ​​silica (C) is 100 m² 2 A thermoplastic resin composition according to [1] or [2], wherein the amount is 1 / g or more. [4]: A thermoplastic resin composition according to any one of [1] to [3], wherein the content of organopolysiloxane (B) is 0.5 to 20% by mass of 100% by mass of the thermoplastic resin composition. [5]: A thermoplastic resin composition according to any one of [1] to [4], wherein organopolysiloxane (B) contains dimethylpolysiloxane. [6]: A thermoplastic resin composition according to any one of [1] to [5], wherein the number average degree of polymerization of organopolysiloxane (B) is 1,000 to 5,000. [7]: The organopolysiloxane (B) has a storage elastic modulus of 1×10 1 Pa or more and 1×10 5 Pa or less at 25°C, a strain of 1%, and a frequency of 0.1 rad / second, and is the thermoplastic resin composition according to any one of [1] to [6]. [8]: The thermoplastic resin composition according to any one of [1] to [7], further comprising a pigment (D). [9]: The thermoplastic resin composition according to any one of [1] to [8], which is for sliding parts.

[10] : A molded body formed from the thermoplastic resin composition according to any one of [1] to [9]. [Advantages of the Invention]

[0010] According to the present invention, it is possible to provide a thermoplastic resin composition having high slidability, the slidability of which is continuously maintained, excellent scratch resistance, and capable of retaining mechanical properties and moldability such as tensile elongation rate, and a molded body obtained from the thermoplastic resin composition. In particular, it is possible to provide a thermoplastic resin composition that can be suitably used for sliding parts. [Embodiments for Carrying Out the Invention]

[0011] Hereinafter, the present invention will be described in detail. In addition, in this specification, the numerical range specified using "~" shall include the numerical values described before and after "~" as the range of the lower limit value and the upper limit value. In addition, the "main component" means the component having the largest blending amount in the component. Unless otherwise noted, the various components appearing in this specification may be used alone or in combination of two or more. The numerical values specified in this specification are values obtained by the methods disclosed in the embodiments or examples.

[0012] [Thermoplastic Resin Composition] The thermoplastic resin composition of the present invention is used to form a molded article and comprises a thermoplastic resin (A), an organopolysiloxane (B) satisfying the following conditions (1) and (2), and silica (C). (1) The number-average molecular weight (Mn) is between 150,000 and 500,000, the weight-average molecular weight (Mw) is between 200,000 and 1,000,000, and the Mw / Mn ratio is between 1.0 and 3.0. (2) The loss tangent (tanδ) in dynamic viscoelasticity measurements at 25°C, 1% strain, and a frequency of 0.1 rad / sec is 1 or greater. The thermoplastic resin composition of the present invention can be suitably used for sliding parts.

[0013] <Thermoplastic resin (A)> In this invention, the thermoplastic resin (A) is a resin that softens and becomes plastic when heated to a suitable temperature, and solidifies when cooled. Examples of thermoplastic resins (A) that can be used include polyamide resins (PA), acrylic resins, polystyrene resins (PS), styrene resins such as acrylonitrile-butadiene-styrene copolymer resins (ABS), polyester resins, polycarbonate resins (PC), polyethylene resins (PE), polypropylene resins (PP), and other polyolefin resins, cycloolefin polymers (COP), polyphenylene ether resins (PPE), polyacetal resins (POM), polyester resins, polyvinyl chloride resins, and polyetherimide resins. Among these, polyacetal resin, styrene resin, polyolefin resin, polycarbonate resin, polyamide resin, and polyester resin are preferred in terms of sliding properties as well as a balance between cost and mechanical properties, with polyacetal resin or styrene resin being more preferred in terms of sliding properties.

[0014] From the viewpoint of achieving both mechanical properties and sliding properties, the content of thermoplastic resin (A) is preferably 60% by mass or more, more preferably 75% by mass or more, and even more preferably 80-99% by mass, based on 100% by mass of the thermoplastic resin composition.

[0015] [Polyolefin resins] Examples of polyolefin resins include homopolymers of α-olefins having approximately 2 to 8 carbon atoms, such as ethylene, propylene, and 1-butene, and (co)polymers of these α-olefins with other α-olefins having approximately 2 to 18 carbon atoms, such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 1-hexene, 4-methyl-1-hexene, 1-heptene, 1-octene, 1-decene, and 1-octadecene.

[0016] Specifically, examples include ethylene homopolymers such as linear low-density polyethylene resin (LLDPE), low-density polyethylene resin (LDPE), and high-density polyethylene resin (HDPE); ethylene copolymers such as ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-propylene-1-butene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-1-hexene copolymer, ethylene-1-heptene copolymer, and ethylene-1-octene copolymer; and propylene copolymers such as propylene homopolymer (homoPP), propylene-ethylene block copolymer (blockPP), propylene-ethylene random copolymer (randomPP), propylene-ethylene-1-butene copolymer, propylene-ethylene-4-methyl-1-pentene copolymer, and propylene-ethylene-1-hexene copolymer. These polyolefin resins may be used individually or in combination of two or more types. Propylene resins are preferred because they can achieve high mechanical properties, and among them, propylene homopolymers (homoPP) are even more preferred because they can increase the load deflection temperature.

[0017] Specific examples of polyolefin resins include Prime PolyPro J229E (manufactured by Prime Polymer, random PP, MFR 50g / 10min), Prime PolyPro J708UG (block PP, MFR 45g / 10min), and Sun Allomer PM900A (manufactured by Sun Allomer, homo PP, MFR 30g / 10min).

[0018] [Styrene resin] Styrene resins are resins that use styrene monomers as monomers. Examples include homopolymers of styrene monomers, as well as styrene resins obtained by copolymerizing them with other vinyl monomers or rubbery polymers, etc., as needed. Styrene resins are preferably given a glass transition temperature of 0°C or higher.

[0019] Examples of styrene monomers include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinylnaphthalene, methoxystyrene, monobromstyrene, dibromstyrene, fluorostyrene, and tribromstyrene, among which styrene is particularly preferred from the viewpoint of excellent moldability.

[0020] Other vinyl monomers copolymerizable with styrene monomers include vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, aryl esters of acrylic acid such as phenyl acrylate and benzyl acrylate, alkyl esters of acrylic acid such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, cyclohexyl acrylate, and dodecyl acrylate, aryl methacrylates such as phenyl methacrylate and benzyl methacrylate, and methyl methacrylate. Examples include alkyl methacrylates such as methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, cyclohexyl methacrylate, and dodecyl methacrylate; epoxy group-containing methacrylates such as glycidyl methacrylate; maleimide monomers such as maleimide, N-methyl maleimide, and N-phenyl maleimide; and α,β-unsaturated carboxylic acids and their anhydrides, such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, phthalic acid, and itaconic acid.

[0021] Examples of rubbery polymers copolymerizable with styrene monomers include polybutadiene, polyisoprene, random and block copolymers of styrene-butadiene, acrylonitrile-butadiene copolymers, copolymers of alkyl acrylate or alkyl methacrylate and butadiene, diene copolymers such as butadiene-isoprene copolymers, copolymers of ethylene and α-olefins such as ethylene-propylene random and block copolymers, random and block copolymers of ethylene-butene, copolymers of ethylene and unsaturated carboxylic acid esters such as ethylene-methyl methacrylate copolymers and ethylene-butyl acrylate copolymers, copolymers of ethylene and aliphatic vinyls such as ethylene-vinyl acetate copolymers, non-conjugated dienate polymers of ethylene and propylene such as ethylene-propylene-hexadiene copolymers, acrylic rubbers such as butyl polyacrylate, and composite rubbers having a structure in which the polyorganosiloxane rubber component and the polyalkyl (meth)acrylate rubber component are intertwined with each other so that they cannot be separated.

[0022] Examples of styrene-based resins composed of these monomers include polystyrene, styrene-butadiene-styrene copolymer (SBS), high-impact polystyrene (HIPS), acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), methyl methacrylate-butadiene-styrene copolymer (MBS resin), methyl methacrylate-acrylonitrile-butadiene-styrene copolymer (MABS resin), acrylonitrile-acrylic rubber-styrene copolymer (AAS resin), acrylonitrile-ethylene propylene-rubber-styrene copolymer (AES resin), and styrene-IPN type rubber copolymer, or mixtures thereof.

[0023] Furthermore, as rubbery polymers copolymerizable with styrene monomers, polymers consisting of polybutadiene or polyisoprene, in which the unsaturated bonds are hydrogenated, can also be mentioned. Specific examples of such polymers include hydrogenated styrene-butadiene-styrene copolymer (hydrogenated SBS) and hydrogenated styrene-isoprene-styrene copolymer (SEPS). Among these, acrylonitrile-butadiene-styrene copolymer (ABS resin) is preferred due to its good impact resistance.

[0024] Specific examples of ABS resin include the Sebian T-500SF (manufactured by Daicel Mirise, MFR 25g / 10 min).

[0025] [Polyacetal resin] Polyacetal resins are polymeric compounds whose main constituent unit is the oxymethylene group (-OCH2-). Typical examples include polyacetal homopolymers consisting substantially only of repeating oxymethylene units, and polyacetal copolymers containing oxymethylene units and other monomer units. Polyacetal resins also include copolymers in which branched and / or crosslinked structures are introduced by copolymerizing branching and / or crosslinking components, block copolymers, or graft copolymers having polymeric parts consisting of repeating oxymethylene groups and other polymeric parts.

[0026] Generally, polyacetal homopolymers are produced by polymerization of anhydrous formaldehyde and one or more monomers selected from formaldehyde cyclic oligomers such as trioxane (a cyclic trimer of formaldehyde) and tetraoxane (a cyclic tetramer of formaldehyde). Typically, the polymerization ends are esterified to stabilize them against thermal decomposition.

[0027] Furthermore, polyacetal copolymers are generally produced by copolymerizing a cyclic oligomer of formaldehyde represented by the general formula (CH2O)n [wherein n is an integer of 3 or more] (e.g., the trioxane mentioned above) with a comonomer such as a cyclic ether and / or cyclic formal (e.g., cyclic formals of glycols or diglycols such as ethylene oxide, propylene oxide, epichlorohydrin, 1,3-dioxolane, and 1,4-butanediol formal). Typically, unstable terminal parts are removed by hydrolysis, stabilizing the copolymer against thermal decomposition.

[0028] Furthermore, examples of polyacetal copolymers include branched polyacetal copolymers obtained by copolymerizing a formaldehyde monomer and / or cyclic oligomer with a monofunctional glycidyl ether; and crosslinked polyacetal copolymers obtained by copolymerizing a formaldehyde monomer and / or cyclic oligomer with a polyfunctional glycidyl ether.

[0029] Polyacetal resins include compounds having functional groups such as hydroxyl groups at both or one end. Examples include polyacetal homopolymers having a blocking component, obtained by polymerizing a monomer and / or cyclic oligomer of formaldehyde in the presence of a polyalkylene glycol; and polyacetal copolymers having a blocking component, obtained by copolymerizing a monomer and / or cyclic oligomer of formaldehyde with a cyclic ether and / or cyclic formal in the presence of a compound having a functional group such as a hydroxyl group at both or one of its ends, such as a hydrogenated polybutadiene glycol.

[0030] Specific examples of POM resin include Duracon M90FC (manufactured by Polyplastics Co., Ltd., MFR 9g / 10 min).

[0031] [Polycarbonate resin (PC resin)] As polycarbonate resins (PC resins), for example, resins that can be easily produced by reacting aromatic dihydroxy compounds with carbonate precursors such as phosgene or diester carbonates can be used. The resins can be produced by known reactions, for example, by an interfacial method when using phosgene, or by a transesterification method in which the reaction is carried out in a molten state when using diester carbonates.

[0032] Examples of aromatic dihydroxy compounds include bis(hydroxyaryl)alkanes such as 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxy-3-t-butylphenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, and 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, as well as 1,1-bis(4-hydroxy(hydroxy) Examples include bis(hydroxyaryl)cycloalkanes such as phenyl)cyclopentane and 1,1-bis(4-hydroxyphenyl)cyclohexane, dihydroxydiaryl ethers such as 4,4'-dihydroxydiphenyl ether and 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, dihydroxydiaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide, dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide, and dihydroxydiaryl sulfones such as 4,4'-dihydroxydiphenyl sulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone. In addition to these, piperazine, dipiperidyl hydroquinone, resorcinol, and 4,4'-dihydroxydiphenyl compounds may be used in combination. Furthermore, branched aromatic polycarbonate resins containing polyfunctional compounds such as phloroglucin can also be used.

[0033] Examples of carbonate precursors to be reacted with aromatic dihydroxy compounds include phosgene, diaryl carbonates such as diphenyl carbonate and ditril carbonate, and dialkyl carbonates such as dimethyl carbonate and diethyl carbonate.

[0034] Specific examples of PC resin include Yupiron E-2000 (manufactured by Mitsubishi Engineering Plastics Corporation, MFR 5g / 10 min), etc.

[0035] [Polyamide resin (PA resin)] Specific examples of polyamide resins (PA resins) include -[NH(CH2)5CO]-, -[NH(CH2)6NHCO(CH2)4CO]-, -[NH(CH2)6NHCO(CH2)8CO]-, and -[NH(CH2) 10 CO]-,-[NH(CH2)] 11 A polyamide resin having at least one structural unit selected from the group consisting of CO]- and -[NH(CH2)2NHCO-D-CO]- (where D represents an unsaturated hydrocarbon having 3 to 4 carbon atoms) is preferably used. Specific examples include 6-nylon, 66-nylon, 610-nylon, 11-nylon, 12-nylon, 6 / 66 copolymer nylon, 6 / 610 copolymer nylon, 6 / 11 copolymer nylon, 6 / 12 copolymer nylon, 6 / 66 / 11 copolymer nylon, 6 / 66 / 12 copolymer nylon, 6 / 66 / 11 / 12 copolymer nylon, 6 / 66 / 610 / 11 / 12 copolymer nylon, and dimer acid-based polyamide resins.

[0036] Specific examples of the aforementioned 6-nylon resin include Amiran CM1041-LO (manufactured by Toray Industries, MFR: 21g / 10 min), Amiran CM1007 (manufactured by Toray Industries, MFR: 21g / 10 min), and Unitika Nylon A1020LP (manufactured by Unitika, MFR: 109g / 10 min).

[0037] Specific examples of the aforementioned 66-nylon resin include Amiran CM3001N (manufactured by Toray Industries, MFR: 103g / 10 min).

[0038] [Polyester resin] Examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexylenedimethylene terephthalate (PCT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), and liquid crystal polyester. As a suitable thermoplastic resin (B4), for example, a thermoplastic resin composed of a saturated dicarboxylic acid and a saturated dihydric alcohol can be used. As saturated dicarboxylic acids, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalene-1,4- or 2,6-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenyl dicarboxylic acids, and diphenoxyethanediethanedicarboxylic acids can be used, as well as aliphatic dicarboxylic acids such as adipic acid, sebatic acid, azelaic acid, and decane-1,10-dicarboxylic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid.

[0039] As saturated dihydric alcohols, aliphatic glycols such as ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, hexamethylene glycol, dodecamethylene glycol, neopentyl glycol, alicyclic glycols such as cyclohexanedimethanol, 2,2-bis(4'-β-hydroxyethoxyphenyl)propane, and other aromatic diols can be used.

[0040] Specific examples of polyester resins include Trecon 1401×06 (PBT resin, manufactured by Toray Industries, Ltd., MFR 25g / 10 min).

[0041] <Organopolysiloxane (B)> The thermoplastic resin composition of the present invention contains organopolysiloxane (B). Organopolysiloxanes are silicones in which organic functional groups such as alkyl groups are bonded to the Si-O- in the main chain. Examples include dimethylpolysiloxane, methylvinylpolysiloxane, methylphenylvinylpolysiloxane, and methyltrifluoropropylvinylpolysiloxane. Dimethylpolysiloxane is preferred from the viewpoint of processability and sliding properties when kneaded with thermoplastic resin (A).

[0042] From the viewpoint of balancing sliding properties and mechanical properties, the content of organopolysiloxane (B) is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, per 100% by mass of the thermoplastic resin composition. Furthermore, it is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 1.3% by mass or more.

[0043] Organopolysiloxane (B) has a number-average molecular weight (Mn) of 150,000 to 500,000, a weight-average molecular weight (Mw) of 200,000 to 1,000,000, and a ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn) of 1.0 to 3.0. The number-average molecular weight (Mn) is preferably 150,000 to 400,000, and more preferably 170,000 to 400,000. The weight-average molecular weight (Mw) is preferably 200,000 to 900,000, and more preferably 220,000 to 800,000. The ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn) is preferably 1.0 to 2.5, and more preferably 1.1 to 2.0. By being within these ranges, it becomes possible to have better sliding properties and retention of mechanical properties.

[0044] The number average degree of polymerization of the organopolysiloxane (B) is preferably 1,000 to 10,000, more preferably 1,300 to 7,000, still more preferably 1,500 to 5,000, and particularly preferably 2,000 to 4,000. Also, the property of this organopolysiloxane is in a so-called raw rubber state (non-liquid state) without self-fluidity at room temperature (25°C). By the number average degree of polymerization being 1,000 or more, the retention rate of mechanical properties is improved, and by being 10,000 or less, it is preferable for better processability.

[0045] The organopolysiloxane (B) has a loss tangent (tanδ) of 1 or more in the dynamic viscoelasticity measurement at 25°C, a strain of 1%, and a frequency of 0.1 rad / second. It is preferably 1.0 to 10.0, and more preferably 1.5 to 8. By being within this range, it has excellent sliding properties. Also, the organopolysiloxane (B) has a storage elastic modulus at 25°C, a strain of 1%, and a frequency of 0.1 rad / second of 1×10 1 Pa or more and 1×10 5 Pa or less, preferably 1×10 2 or more and 1×10 4 Pa or less. By being within this range, it has excellent retention rate of mechanical properties and processability when kneaded with the thermoplastic resin.

[0046] <Silica (C)> The thermoplastic resin composition of the present invention contains silica (C).

[0047] Silica (C) improves the processability of organopolysiloxane (B), and in addition to uniformly mixing the thermoplastic resin and organopolysiloxane (B), contributes to maintaining mechanical strength. Examples include fumed silica and precipitated silica, and those whose surfaces have been hydrophobized with chlorosilane or hexamethyldisilazane are also suitably used. Among these, fumed silica, which has excellent retention of mechanical properties, is preferred.

[0048] The BET specific surface area of ​​silica (C) is 100 m². 2 It is preferable that the amount is 100 to 450 mg / g or more, and more preferably 100 to 450 mg / g or more. 2 / g, more preferably 150-300m 2 It is / g. The specific surface area is 100m². 2 Having a value of 1 / g or more allows for more uniform mixing of thermoplastic resin and organopolysiloxane, resulting in a 450m 2 A value of less than / g is preferable because it provides superior sliding properties. The BET specific surface area was measured using a BET specific surface area measuring device (Macsorb, Mounttech) and a fully automatic specific surface area measuring device (HM-model1208, Mounttech) after pretreatment by drying the silica at 110°C for 15 minutes while degassing.

[0049] The silica (C) content is preferably 0.1 to 10% by mass, more preferably 0.1 to 5.0% by mass, and even more preferably 0.3 to 2.0% by mass, based on the thermoplastic resin composition (100% by mass). This range is preferable because it improves sliding properties and allows for excellent processability when kneading the thermoplastic resin and organopolysiloxane.

[0050] The content ratio (C) / (B) of organopolysiloxane (B) to silica (C) is preferably 0.10 to 0.67, and more preferably 0.12 to 0.60, from the viewpoint of processability of the organopolysiloxane and sliding properties when formed into a molded article.

[0051] <Pigment (D)> Thermoplastic resin compositions can be colored with pigments to produce molded articles with excellent design or that are easily identifiable. The pigments are not particularly limited and can be those that are generally available, but from the viewpoint of the natural environment, it is preferable that they are substantially free of pigments containing cadmium, lead, chromium, arsenic, mercury, copper, selenium, nickel, molybdenum, and fluorine. They may be organic pigments, inorganic pigments, or dyes. Inorganic pigments are preferred.

[0052] As an example, the inorganic pigment may be one or more selected from the group consisting of metal compounds such as Ti, Pb, Fe, and Cr, and carbon black. The metal compound is preferably a metal oxide or metal hydroxide. Specific examples of the inorganic pigment include TiO2 and zinc oxide as white inorganic pigments; carbon black and graphite as black inorganic pigments; IOR, cadmium red, and red lead (Pb3O4) as red inorganic pigments; chrome yellow, zinc chromate, and cadmium yellow as yellow inorganic pigments; and chrome green and zinc green as green inorganic pigments. Carbon black is preferred from the viewpoint of durability.

[0053] The pigment (D) content is preferably 0.1 to 25% by mass, and more preferably 0.1 to 10% by mass, based on the thermoplastic resin composition (100% by mass), from the viewpoint of coloring power and mechanical properties.

[0054] When the resin composition contains a pigment, it is preferable to use a dispersant to disperse the pigment. Examples of dispersants include fatty acid metal salts, fatty acid amides, olefin waxes, and polyester waxes. The fatty acid component of the fatty acid metal salt is preferably a chain-like carboxylic acid having 6 to 30 carbon atoms, and may be linear or branched, and may have only saturated bonds or only unsaturated bonds.

[0055] <Optional ingredients> The thermoplastic resin composition of the present invention may optionally contain additives such as organopolysiloxanes other than organopolysiloxane (B), silica other than silica (C), antistatic materials, weather stabilizers, antioxidants, coupling agents, crystal nucleating agents, and resin fillers, for the purpose of improving the weather resistance, conductivity, moldability, and productivity of the resin composition. Examples of antistatic materials include carbon materials such as carbon black, carbon nanotubes, carbon fibers, graphite, and graphene, metal particles, and ionic liquids, while examples of resin fillers include talc and calcium carbonate.

[0056] The thermoplastic resin composition preferably does not contain volatile components. In 100% by mass of the thermoplastic resin composition, volatile components such as solvents and low molecular weight components are preferably 5% by mass or less, and more preferably 1% by mass or less.

[0057] <Method for producing thermoplastic resin compositions> The method for producing the thermoplastic resin composition of the present invention is not particularly limited. For example, a thermoplastic resin (A), organopolysiloxane (B), silica (C), and additives as needed can be mixed in a Henschel mixer, tumbler, disper, etc., and then mixed or melt-kneaded in a batch-type kneader such as a kneader, roll mill, super mixer, Henschel mixer, Shugi mixer, vertical granulator, high-speed mixer, fur matrix, ball mill, steel mill, sand mill, vibratory mill, attritor, Banbury mixer, twin-screw extruder, single-screw extruder, rotor-type twin-screw kneader, etc. to obtain a resin composition in the form of pellets, powders, granules, or beads. In this invention, it is preferable to use a twin-screw extruder or a single-screw extruder for melt mixing.

[0058] The thermoplastic resin composition of the present invention may be a compound that is used for molding in its original composition without dilution with thermoplastic resin (A). Alternatively, it may be a masterbatch containing relatively high concentrations of organopolysiloxane (B) and silica (C), which is diluted with thermoplastic resin (A) during molding.

[0059] Molded body The molded article is formed from the thermoplastic resin composition of the present invention.

[0060] The molded body can be formed by melting and mixing a thermoplastic resin composition consisting of a compound or masterbatch and a diluted resin in a molding machine typically set to 50°C to 350°C, then shaping the molded body and cooling it. The temperature of the molding machine can be any temperature at which the thermoplastic resin (A) softens, but preferably it is at least 30°C higher than the softening point of the main component thermoplastic resin.

[0061] When forming a molded product from a masterbatch and a diluted resin, it is desirable to blend 3 to 20 parts by mass of the masterbatch with 100 parts by mass of the base diluted resin, from the viewpoint of processability and cost when preparing the masterbatch. Furthermore, the diluent resin may be the same as or different from the thermoplastic resin (A) used in the masterbatch, but it is preferable that it be the same.

[0062] The molding method can include, for example, extrusion molding, injection molding, blow molding, compression molding, transfer molding, film molding such as T-die molding and inflation molding, calendering, spinning, etc. Injection molding is preferred because it can be molded into any shape.

[0063] The shape of the molded body is not particularly limited, but examples include plates, rods, fibers, tubes, pipes, bottles, and films. Two or more of the obtained molded bodies may be fitted together and used in combination.

[0064] The content of organopolysiloxane (B) in the molded article is 0.5% by mass or more and 10% by mass or less, based on the molded article as the reference (100% by mass), from the viewpoint of achieving both sliding properties and mechanical properties. It is preferably 1.3% by mass or more, and more preferably 5% by mass or less. The silica (C) content in the molded article is preferably 0.1% by mass or more and 10% by mass or less, based on the molded article as the reference (100% by mass), from the viewpoint of sliding properties and processability when kneading thermoplastic resin and organopolysiloxane. It is preferably 0.3% by mass or more, and more preferably 2.0% by mass or less.

[0065] The molded body can be used, for example, in sliding parts such as gears and bearings, electrical and electronic equipment such as printer feeders, agricultural materials such as agricultural sheets, and building components such as fixed-fit support materials. Because the molded body of the present invention has an excellent balance of lubricity, molded appearance, and mechanical properties, it can be suitably used in sliding parts. [Examples]

[0066] The present invention will be described in more detail below with reference to examples, but the following examples are not intended to limit the present invention in any way. In the examples, "parts" refers to "parts by mass" and "%" refers to "percentage by mass".

[0067] Furthermore, the MFR of thermoplastic resins, the average molecular weight, number-average degree of polymerization, and dynamic viscoelasticity of organopolysiloxanes, and the BET specific surface area of ​​silica were measured using the following methods.

[0068] <MFR of thermoplastic resin (A)> MFR was measured in accordance with JIS K 7210:1999. Specifically, it was measured using a "Melt Indexer" manufactured by Toyo Seiki Co., Ltd., under conditions of a temperature of 230°C and a load of 2.16 kgf.

[0069] <Average molecular weight of organopolysiloxanes> The weight-average molecular weight (Mw), number-average molecular weight (Mn), and the ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn) were measured by gel permeation chromatography (GPC). A GPC instrument (Tosoh Corporation, product name HLC-8121GPC / HT) and column (Tosoh Corporation, product name TSKgel GMHhr-H(20)HT) were used. The molecular weight calibration curve was calibrated using polystyrene samples with known molecular weights. Mw and Mn were determined as linear polyethylene equivalents.

[0070] <Number average degree of polymerization of organopolysiloxanes> The number-average degree of polymerization was determined from the number-average molecular weight obtained in polystyrene equivalent, measured by gel permeation chromatography (GPC).

[0071] <Dynamic viscoelasticity measurement of organopolysiloxanes> The storage modulus and loss tangent (tanδ) were measured using a dynamic viscoelasticity measuring instrument DMA-Q800 (manufactured by TA Instruments) at a temperature of 25°C, a strain of 1%, and by varying the frequency from 100 to 0.1 rad / s. The values ​​for the storage modulus and loss tangent (tanδ) at a frequency of 0.1 rad / s were then determined.

[0072] <BET specific surface area of ​​silica> 0.03 g of silica was weighed using an electronic balance (Sartorius, MSA225S100DI), and then dried at 110°C for 15 minutes while degassing. After that, the BET specific surface area of ​​the silica was measured using a fully automatic specific surface area analyzer (Mountain Tech, HM-model1208).

[0073] The materials used in the example are as follows: <Thermoplastic resin (A)> • (A-1) Prime Polypropylene J708UG (manufactured by Prime Polymer, polyolefin resin, block PP, MFR 45g / 10 min) • (A-2) Sebian T-500SF (manufactured by Daicel Mirise, styrene resin, MFR 25g / 10 min) • (A-3) Duracon M90FC (manufactured by Polyplastics, polyacetal resin, MFR 9g / 10 min) • (A-4) Yupiron E-2000 (manufactured by Mitsubishi Engineering Plastics, polycarbonate resin, MFR 5g / 10 min) • (A-5) Amiran CM1041-LO (manufactured by Toray Industries, Inc., polyamide resin, MFR: 21g / 10 min) • (A-6) Trecon 1401 x 06 (Toray Industries, Ltd., polyester resin, PBT resin, MFR 25g / 10 min)

[0074] <Organopolysiloxane (B), etc.> • (B-1) Dimethylpolysiloxane from Production Example 1 (average molecular weight Mn 250,000, Mw 300,000, Mw / Mn 1.2, number average degree of polymerization 2,400) • (B-2) Dimethylpolysiloxane from Production Example 2 (average molecular weight Mn 170,000, Mw 220,000, Mw / Mn 1.29, number average degree of polymerization 1,600) • (B-3) Dimethylpolysiloxane from Production Example 3 (average molecular weight Mn 400,000, Mw 980,000, Mw / Mn 2.5, number average degree of polymerization 3,800) • (B'-4) GFD2071P (MIDGOLD, average molecular weight Mn 170,000, Mw 200,000, Mw / Mn 1.2, number average degree of polymerization 1,600) • (B'-5) Dimethylpolysiloxane from Production Example 4 (average molecular weight Mn 200,000, Mw 700,000, Mw / Mn 3.5, number average degree of polymerization 1,900) • (B'-6) Dimethylpolysiloxane from Production Example 5 (average molecular weight Mn 140,000, Mw 180,000, Mw / Mn 1.3, number average degree of polymerization 1,350) • (B'-7) Dimethylpolysiloxane from Production Example 6 (average molecular weight Mn 550,000, Mw 1,100,000, Mw / Mn 2.0, number average degree of polymerization 5,300)

[0075] [Table 1]

[0076] (Manufacturing Examples 1-6) An introductory aqueous solution was prepared by mixing 49% by mass of dioxane, 1% by mass of hydrogen chloride, and 50% by mass of water. This aqueous solution was poured into 200 g of dimethyldichlorosilane in a reaction vessel at a rate of 0.5 to 5 g / min. The number average molecular weight and weight average molecular weight were adjusted by externally controlling the dropping rate of the introductory aqueous solution and the reaction temperature. 120 parts by mass of acetone were added to 100 parts by mass of the obtained dimethylpolysiloxane, and after stirring for 30 minutes, the mixture was allowed to stand for 15 minutes to separate the dimethylpolysiloxane oil layer. This extraction operation was repeated 10 to 20 times to adjust the Mw / Mn ratio and obtain (B1 to 3, 5 to 7).

[0077] <Silica (C)> • (C-1) Aerosil 200 (fumed silica, manufactured by Nippon Aerosil Co., Ltd., BET specific surface area 200 m²) 2 / g) • (C-2) Aerosil 380 (fumed silica, manufactured by Nippon Aerosil Co., Ltd., BET specific surface area 400 m²) 2 / g) • (C-3) Aerosil 50 (fumed silica, manufactured by Nippon Aerosil Co., Ltd.) BET specific surface area 50m² 2 / g)

[0078] <Pigment (D)> • (D-1) Carbon Black (Mitsubishi Chemical Corporation, #52)

[0079] (Example 1) (Manufacturing of thermoplastic resin compositions) 97.7 parts of thermoplastic resin (A-1), 2 parts of organopolysiloxane (B-1), and 0.3 parts of silica (C-1) were melt-kneaded, extruded at 200°C using a single-screw extruder (manufactured by Shibaura Machinery Co., Ltd.), and granulated to obtain a thermoplastic resin composition. The content ratio (C) / (B) of organopolysiloxane (B) to silica (C) was 0.15.

[0080] (Examples 2-9, 13-16, Comparative Examples 1-4) Thermoplastic resin compositions were obtained in the same manner as in Example 1, except that the materials and their respective amounts (parts by mass) were changed as shown in Table 2.

[0081] (Examples 10-12) Thermoplastic resin compositions were obtained in the same manner as in Example 1, except that the materials and their respective amounts (parts by mass) were changed to those shown in Table 2, and the extruder temperature was changed to 250°C.

[0082] Note that the C / B ratio in Table 2 represents the ratio of the content of organopolysiloxane (B) to silica (C).

[0083] Evaluation of thermoplastic resin compositions and molded articles The thermoplastic resin composition and molded articles of the present invention were evaluated by the following method. The results are shown in Table 3.

[0084] <Slippery> (Sliding properties) A 90mm x 110mm x 2mm flat plate, formed from a thermoplastic resin composition using an injection molding machine, was used as a multipurpose test specimen and tested using a reciprocating friction and wear tester (Toyo Precision Co., Ltd., AFT-15MS model). A pin with a 5mm diameter sphere at its tip, made from the same thermoplastic resin used in the production of the thermoplastic resin composition, was used as the mating material. A reciprocating sliding test was conducted with the tip of the pin in contact with the surface of the multipurpose test specimen at a temperature of 23°C, humidity of 50%, linear velocity of 30mm / sec, reciprocating distance of 10mm, load of 19.6N, and 100 reciprocating cycles. The average friction coefficient over 100 reciprocating cycles was defined as the friction coefficient. The sliding properties were evaluated by the coefficient of friction. A lower coefficient of friction indicates better sliding properties. [Evaluation Criteria] +++: Friction coefficient less than 0.10 ++: Friction coefficient is 0.10 or greater and less than 0.15 + : Friction coefficient is 0.15 or higher and less than 0.20 - : Friction coefficient is 0.20 or higher

[0085] (Scratch resistance) In the above reciprocating sliding test, scratch resistance was evaluated as follows based on the degree of scratching of the sample after measurement. [Evaluation Criteria] +++: No scratches are visible from any angle. ++: Upon close inspection, a slight scratch is visible, but it is not visible from certain angles. +: Upon closer inspection, scratches are visible, but no unevenness caused by resin chipping is seen on the molded body. - : Scratches are clearly visible, and the molded surface has unevenness due to resin abrasion.

[0086] (Sliding durability) A 90mm x 110mm x 2mm flat plate, formed from a thermoplastic resin composition using an injection molding machine, was left in a gear oven for 1000 hours. This plate was then used as a multi-purpose test specimen and tested using a reciprocating friction and wear tester (Toyo Precision Co., Ltd., AFT-15MS model). The mating material was a pin with a 5mm diameter sphere at its tip, made from the same thermoplastic resin used in the production of the thermoplastic resin composition. A reciprocating sliding test was conducted with the tip of the pin in contact with the surface of the multi-purpose test specimen at a temperature of 23°C, humidity of 50%, linear velocity of 30mm / sec, reciprocating distance of 10mm, load of 19.6N, and 10,000 reciprocating cycles. The average friction coefficient over 10,000 reciprocating cycles was defined as the friction coefficient. A lower coefficient of friction indicates better sliding properties and that these sliding properties can be sustained. [Evaluation Criteria] +++: Friction coefficient less than 0.10 ++: Friction coefficient is 0.10 or greater and less than 0.15 + : Friction coefficient is 0.15 or higher and less than 0.20 - : Friction coefficient is 0.20 or higher

[0087] <Moldability> Ten 90mm x 110mm x 2mm flat plates were molded from a thermoplastic resin composition using an injection molding machine. The moldability of the molded products was determined by visually inspecting the resulting plates for cracks and silver formation, and evaluating them according to the following criteria. [Evaluation Criteria] ++: All 10 flat plates showed no molding defects. + : Two or fewer out of ten flat plates have cracks or silvering. - : Three or more out of ten flat plates have cracks or silvering.

[0088] <Mechanical Properties> (Impact resistance) Impact resistance was evaluated using the Charpy impact test in the following manner. Thermoplastic resin compositions were subjected to tensile testing using a Charpy impact tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.) in accordance with JIS K7111:2012 (Plastics - Charpy impact properties) using an injection molding machine, and the Charpy impact strength (kJ / m²) was determined. 2 ) was measured. A higher Charpy impact strength indicates better impact resistance. [Evaluation Criteria] +++: Charpy impact strength is 15kJ / m 2 That's all. ++: Charpy impact strength is 10 kJ / m 2 More than 15kJ / m 2 less than + : Charpy impact strength of 5 kJ / m 2 More than 10kJ / m 2 less than - : Charpy impact strength is 5 kJ / m 2 less than

[0089] (rigidity) The stiffness was evaluated by the retention rate of the bending modulus of elasticity using the following method. A 100mm x 10mm x 4mm strip test specimen was prepared from the thermoplastic resin composition using an injection molding machine. The flexural modulus (GPa) was measured in accordance with JIS K7171:2016 using an Instron universal testing machine with a three-point bending jig, at a span of 64mm, a speed of 2mm / min, 23°C, and a 50% RH environment. The retention rate of the flexural modulus was calculated using the thermoplastic resin alone as the reference. The more the bending modulus of elasticity is maintained (100%), the better the rigidity can be considered to be. [Evaluation Criteria] +++: The flexural modulus retention rate is 95% or higher. ++: The flexural modulus retention rate is 80% or more and less than 95%. + : The flexural modulus retention rate is 75% or more and less than 80%. - : The flexural modulus retention rate is less than 75%.

[0090] [Table 2]

[0091] [Table 3]

[0092] As shown in Table 2, the thermoplastic resin composition of the present invention possesses high sliding properties, and these sliding properties are maintained over time. Furthermore, it was confirmed that it has excellent scratch resistance and can maintain mechanical properties such as impact resistance and rigidity, as well as moldability. Therefore, it can be said that it is particularly suitable for use in sliding parts.

Claims

1. A thermoplastic resin composition comprising a thermoplastic resin (A), an organopolysiloxane (B) satisfying the following conditions (1) and (2), and silica (C). (1) The number-average molecular weight (Mn) is 150,000 to 500,000, the weight-average molecular weight (Mw) is 200,000 to 1,000,000, and the ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn) is 1.0 to 3.

0. (2) The loss tangent (tanδ) in the dynamic viscoelasticity measurement at 25°C, strain 1%, and frequency 0.1 rad / sec is 1 or greater.

2. The thermoplastic resin composition according to claim 1, wherein the content ratio (C) / (B) of organopolysiloxane (B) to silica (C) is 0.10 to 0.

67.

3. The BET specific surface area of ​​silica (C) is 100 m². 2 The thermoplastic resin composition according to claim 1, wherein the amount is 1 / g or more.

4. The thermoplastic resin composition according to claim 1, wherein the content of organopolysiloxane (B) is 0.5 to 20% by mass of 100% by mass of the thermoplastic resin composition.

5. The thermoplastic resin composition according to claim 1, wherein organopolysiloxane (B) contains dimethylpolysiloxane.

6. The thermoplastic resin composition according to claim 1, wherein the number average degree of polymerization of organopolysiloxane (B) is 1,000 to 5,000.

7. Organopolysiloxane (B) has a storage modulus of 1 × 10⁻¹⁰ at 25°C, 1% strain, and a frequency of 0.1 rad / s. １ Pa or more 1×10 ５ The thermoplastic resin composition according to claim 1, wherein the temperature is Pa or less.

8. The thermoplastic resin composition according to claim 1, further comprising a pigment (D).

9. A thermoplastic resin composition according to claims 1 to 8, for use in sliding parts.

10. A molded article formed from the thermoplastic resin composition described in claims 1 to 8.

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