Polycarbonate resin composition and molded article

Abstract

To provide a polycarbonate resin composition with antistatic properties and resistance to thermal degradation.SOLUTION: A polycarbonate resin composition contains a resin main material containing a polycarbonate resin (P) and a rubber-reinforced resin (G), an antistatic agent (E), and alkyl phosphate (F). Preferably the alkyl phosphate (F) includes a C1-30 alkyl group. The rubber-reinforced resin (G) may include a graft copolymer (A), a copolymer (B), and an organic matting agent. The antistatic agent (E) may include an ion-conductive polymer.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polycarbonate resin composition containing an antistatic agent and a molded product.

Background Art

[0002] Polycarbonate resins and alloy resins obtained by melt-kneading these with other resins are used in many applications such as mechanical parts, automotive parts, electrical and electronic parts, and office equipment parts due to their excellent properties such as mechanical properties, dimensional stability, and flame retardancy. In addition, in these applications, in recent years, the demand for excellent appearance has been increasing day by day. For excellent appearance, color and product design are emphasized. However, when trying to remove dust attached during use by wiping with a cloth or the like, scratches are made on the molded product, which causes damage to the appearance. Furthermore, in recent years, the demand for a matte appearance that provides a calm texture and a high-class feeling has been increasing. However, when dust adheres to a molded product having a matte appearance, it is even more difficult to remove, and it is regarded as a problem that causes damage to the appearance.

[0003] It is widely known to blend an antistatic agent into a resin composition for the purpose of imparting antistatic properties. As an antistatic agent, a method of using a polyether ester amide (Patent Document 1) has been proposed, but it has the drawback of deteriorating thermal stability during melt-kneading and injection molding. In addition, since a large amount needs to be blended to exhibit antistatic properties, there is a problem that the mechanical properties, which are the advantages of polycarbonate resins and their alloy resins, are sacrificed.

[0004] A method of adding a surfactant as an antistatic agent is also widely practiced (Patent Document 2). However, while this method improves antistatic performance, it has problems such as deterioration of heat resistance during melt-kneading and injection molding, deterioration of physical properties, and occurrence of appearance defects (silver streaks), and none of them could meet the market requirements in recent years.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2002-129026 [Patent Document 2] Japanese Patent Application Publication No. 6-93176 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The present invention provides a polycarbonate resin composition having antistatic properties and heat decomposition resistance. [Means for solving the problem]

[0007] [1] A polycarbonate resin composition comprising a resin main raw material containing polycarbonate resin (P) and rubber-reinforced resin (G), an antistatic agent (E), and an alkyl phosphate (F). [2] The polycarbonate resin composition according to [1], wherein the alkyl phosphate (F) has 1 to 30 carbon atoms in the alkyl group. [3] The polycarbonate resin composition according to [1] or [2], wherein the rubber-reinforced resin (G) comprises a graft copolymer (A) and a copolymer (B), the graft copolymer (A) is formed by a rubbery polymer and graft chains bonded to the rubbery polymer, the proportion of the rubbery polymer to the total mass of the graft copolymer (A) is greater than 20% by mass and 80% by mass or less, the proportion of monomer components (a) constituting the graft chains is 20% by mass or more and less than 80% by mass, the sum of the proportion of the rubbery polymer and the proportion of monomer components (a) is 100% by mass, and the content of monomer units derived from aromatic vinyl compound (b1) in copolymer (B) is 50 to 80% by mass with respect to the total mass of copolymer (B). [4] The polycarbonate resin composition according to [3], wherein the rubber-reinforced resin (G) further comprises an organic matting agent different from the graft copolymer (A) and copolymer (B). [5] The polycarbonate resin composition according to [4], comprising one or more organic matting agents selected from acid-modified rubber, epoxy-modified rubber, and amorphous diene rubber-modified copolymer resins obtained by vulcanization reaction of styrene-conjugated diene rubber block copolymer and conjugated diene rubber. [6] The antistatic agent (E) is a polycarbonate resin composition according to any one of [1] to [5], comprising an ion-conducting polymer. [7] A polycarbonate resin composition according to any one of [1] to [6], comprising 0.1 to 20 parts by mass of an antistatic agent (E) and 0.01 to 5 parts by mass of an alkyl phosphate (F) per 100 parts by mass of a total of polycarbonate resin (P) and rubber-reinforced resin (G). [8] A molded article obtained by injection molding a polycarbonate resin composition as described in any one of items [1] to [7]. [Effects of the Invention]

[0008] According to the present invention, a polycarbonate resin composition having antistatic properties and heat decomposition resistance can be provided. [Modes for carrying out the invention]

[0009] The following definitions of terms apply throughout this specification and the claims. "(Meth)acrylate" means acrylate or methacrylate. The "~" symbol, which indicates a numerical range, means that the numbers before and after it are included as the lower and upper limits, respectively.

[0010] ≪First aspect≫ A first aspect of the present invention is a polycarbonate resin composition comprising a resin main raw material containing a polycarbonate resin (P) and a rubber-reinforced resin (G), an antistatic agent (E), and an alkyl phosphate (F). The polycarbonate resin composition may optionally contain polycarbonate resin (P), other thermoplastic resins other than rubber-reinforced resin (G) (hereinafter also referred to as "other thermoplastic resins (Z)"), and optional components other than resin components (W), as long as they do not impair the effects of the present invention. The main resin material may be formed solely from polycarbonate resin (P) and rubber-reinforced resin (G), or it may contain other resins.

[0011] <Polycarbonate resin (P)> Polycarbonate resin (P) is a resin having carbonate bonds (carbonate ester bonds) in its main chain. While polycarbonate resin (P) is not particularly limited, examples include aromatic polycarbonate resins, aliphatic polycarbonate resins, aliphatic-aromatic polycarbonate resins, and aromatic polyester carbonate resins. These polycarbonate resins (P) may also be modified with R-CO- groups or R'-O-CO- groups at their ends (where R and R' both represent organic groups).

[0012] As for the polycarbonate resin (P), at least one selected from the group consisting of aromatic polycarbonate resin and aromatic polyester carbonate resin is preferred from the viewpoint of improving the impact resistance and heat resistance of the molded product, and aromatic polycarbonate resin is more preferred from the viewpoint of further improving impact resistance.

[0013] Aromatic polycarbonate resin is a polymer having a structural unit represented by the general formula -(-O-X1-OC(=O)-). In the general formula, X1 is a hydrocarbon group having one or more aromatic rings, or a group in which a heteroatom or heterobond is introduced to the hydrocarbon group. In X1, the atom directly bonded to the oxygen atom adjacent to X1 is a carbon atom constituting the aromatic ring.

[0014] Aromatic polycarbonate resins include, for example, reaction products obtained by transesterification reactions between aromatic dihydroxy compounds and diester carbonates, polycondensates obtained by interfacial polycondensation between aromatic dihydroxy compounds and phosgene, and polycondensates obtained by the pyridine method between aromatic dihydroxy compounds and phosgene.

[0015] Aromatic dihydroxy compounds can be any compound having two hydroxyl groups bonded to an aromatic ring within the molecule, such as hydroquinone, resorcinol, dihydroxybenzene, 4,4'-biphenol, 2,2-bis(4-hydroxyphenyl)propane (hereinafter referred to as "bisphenol A"), 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl-3-methylphenyl)propane, 2,2-bis(3-tert-butyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)methane, 1,1-bis(p-hydroxyphenyl)ethane, 2,2-bis(p-hydroxyphenyl)butane, 2,2-bis(p-hydroxyphenyl)pentane, 1,1-bis(p-hydroxyphenyl)cyclohexane, 1,1-bis(p-hydroxyphenyl)- Examples include 4-isopropylcyclohexane, 1,1-bis(p-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(p-hydroxyphenyl)-1-phenylethane, 9,9-bis(p-hydroxyphenyl)fluorene, 9,9-bis(p-hydroxy-3-methylphenyl)fluorene, 4,4'-(p-phenylenediisopropylidene)bisphenol, 4,4'-(m-phenylenediisopropylidene)bisphenol, bis(p-hydroxyphenyl)oxide, bis(p-hydroxyphenyl)ketone, bis(p-hydroxyphenyl)ether, bis(p-hydroxyphenyl)ester, bis(p-hydroxyphenyl)sulfide, bis(p-hydroxy-3-methylphenyl)sulfide, bis(p-hydroxyphenyl)sulfone, bis(3,5-dibromo-4-hydroxyphenyl)sulfone, and bis(p-hydroxyphenyl)sulfoxide. These aromatic dihydroxy compounds may be used alone or in combination of two or more.

[0016] As the aromatic dihydroxy compound, a compound having a hydrocarbon group between two benzene rings is preferred. In this compound, examples of the hydrocarbon group include an alkylene group. The hydrocarbon group may be a halogen-substituted hydrocarbon group. The benzene ring may be one in which a hydrogen atom contained in the benzene ring is substituted with a halogen atom. Examples of the compound having a hydrocarbon group between two benzene rings include bisphenol A, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl-3-methylphenyl)propane, 2,2-bis(3-tert-butyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)methane, 1,1-bis(p-hydroxyphenyl)ethane, 2,2-bis(p-hydroxyphenyl)butane, and the like. Among these, bisphenol A is preferred. These compounds having a hydrocarbon group between two benzene rings may be used alone or in combination of two or more.

[0017] Examples of the diester carbonate used for obtaining the aromatic polycarbonate by transesterification reaction include dimethyl carbonate, diethyl carbonate, di-tert-butyl carbonate, diphenyl carbonate, ditolyl carbonate, and the like. These diester carbonates may be used alone or in combination of two or more.

[0018] The polycarbonate resin (P) may be used alone or in combination of two or more. For example, two or more types of polycarbonate resins having different viscosity average molecular weights may be used in combination.

[0019] The molecular weight of the polycarbonate resin (P) is arbitrary and not particularly limited, but the viscosity-average molecular weight (Mv) calculated from the solution viscosity is usually preferably 15,000 to 40,000, more preferably 17,000 to 30,000, and particularly preferably 18,000 to 28,000. If the viscosity-average molecular weight is above the lower limit, there is a margin in the material performance design even if a decrease in impact resistance or a change in moldability occurs due to thermal decomposition of the polycarbonate resin. Also, if the viscosity-average molecular weight is below the upper limit, the initial fluidity of the polycarbonate resin composition is improved.

[0020] The viscosity-average molecular weight (Mv) of polycarbonate resin (P) is measured by the solution viscosity method. Specifically, a solution (sample) prepared by dissolving 0.7 g of polycarbonate resin (P) in 100 mL of methylene chloride is used to determine the intrinsic viscosity [η] (unit dl / g) at 25°C using an Ubbelohde viscometer, and the viscosity-average molecular weight (Mv) is calculated using the following formula (4). [η] = 1.23 × 10 -4 ×Mv0.83 ···(4)

[0021] <Rubber-reinforced resin (G)> Examples of the rubber-reinforced resin (G) include those containing graft copolymer (A) and copolymer (B). Additionally, an organic matting agent, as described later, may be included as needed.

[0022] [Graft copolymer (A)] Graft copolymer (A) is a copolymer in which monomer component (a) is graft polymerized onto a rubbery polymer. Furthermore, in graft copolymer (A), it is not easy to determine how monomer component (a) is polymerized to the rubbery polymer. In other words, for graft copolymer (A), it is either impossible or impractical to directly identify it based on its structure or properties. Therefore, it is more appropriate to define graft copolymer (A) as "a rubbery polymer in which monomer component (a) has been graft polymerized."

[0023] (Rubber-based polymer) Examples of rubbery polymers constituting the graft copolymer (A) include butadiene-based rubbers such as polybutadiene, styrene-butadiene copolymer, and acrylic acid ester-butadiene copolymer; conjugated diene-based rubbers such as styrene-isoprene copolymer; acrylic-based rubbers such as butyl polyacrylate; olefin-based rubbers such as ethylene-propylene copolymer; and silicone-based rubbers such as polyorganosiloxane. The rubbery polymer may also take the form of a composite rubber structure or a core / shell structure. As for the rubbery polymer, butadiene-based rubber, acrylic-based rubber, or composite rubbery polymers thereof are preferred due to their good balance of color and impact resistance. These rubbery polymers may be used individually or in combination of two or more types.

[0024] The average particle size of the rubbery polymer is preferably 0.20 to 0.50 μm, and more preferably 0.25 to 0.40 μm. If the average particle size of the rubbery polymer is above the lower limit, the impact resistance is improved. Furthermore, if the average particle size of the rubbery polymer is below the upper limit, it is preferable that defects such as scattered dispersion defects (bumps) on the surface of the molded product are less likely to occur. In addition, the initial fluidity of the polycarbonate resin composition is improved. The average particle size of a rubbery polymer can be calculated by measuring the volume-based particle size distribution using a particle size distribution analyzer and then obtaining the resulting particle size distribution. The average particle size of rubbery polymers can be controlled by adjusting the polymerization conditions (temperature, time, etc.) during production, as well as the type of monomer and its blending ratio. However, this does not apply to solution polymerization, bulk polymerization, etc., as these often do not form clearly defined rubber particle sizes.

[0025] While there are no particular restrictions on the method for producing the rubbery polymer, emulsion polymerization is preferred because it allows for easy control of particle size. Known methods can be used for emulsion polymerization, and there are no particular restrictions on the catalysts, emulsifiers, etc. used; various types can be used.

[0026] The rubbery polymer may be enlarged rubber. Furthermore, the average particle size, distribution, etc., can be adjusted by the enlargement process. Methods for enlargement include mechanical agglutination, chemical agglutination, and agglutination using acid group-containing copolymers. Chemical coagulation methods include adding an acidic substance to latex, a rubbery polymer, to destabilize its emulsification stability and coagulate it until the desired particle size is reached, at which point an alkaline substance is added to re-stabilize the latex. Examples of acidic substances include acetic acid, acetic anhydride, sulfuric acid, and phosphoric acid. Examples of alkaline substances include potassium hydroxide and sodium hydroxide.

[0027] One method for agglomeration using an acid group-containing copolymer is to obtain enlarged rubber latex by mixing a rubbery polymer latex with an acid group-containing copolymer latex. Examples of acid group-containing copolymer latex include an acid group-containing copolymer latex obtained by polymerizing monomer components in water, such as an acid group-containing monomer (e.g., a carboxyl group-containing monomer such as (meth)acrylic acid), an alkyl (meth)acrylate monomer, and other monomers copolymerizable therewith as needed. In this embodiment, the enlarged latex is considered to be integrated with the rubbery polymer.

[0028] (Monomer component (a)) The monomer component (a) constituting the graft chain of the graft copolymer (A) includes an aromatic vinyl compound (a1), a vinyl cyanide compound (a2), and optionally another vinyl compound (a3).

[0029] Examples of aromatic vinyl compounds (a1) include styrene, α-methylstyrene, vinyltoluenes (such as p-methylstyrene), halogenated styrenes (such as p-bromostyrene and p-chlorostyrene), p-tert-butylstyrene, dimethylstyrene, and vinylnaphthalene. Among these, styrene and α-methylstyrene are preferred. These aromatic vinyl compounds (a1) may be used individually or in combination of two or more.

[0030] Examples of vinyl cyanide compounds (a2) include acrylonitrile and methacrylonitrile. Among these, acrylonitrile is preferred. These vinyl cyanide compounds (a2) may be used individually or in combination of two or more.

[0031] Other vinyl compounds (a3) ​​are vinyl compounds copolymerizable with aromatic vinyl compounds (a1) and vinyl cyanide compounds (a2) (excluding those that can be used to form acid-modified vinyl copolymers or epoxy-modified vinyl copolymers). Examples of such vinyl compounds include alkyl methacrylates such as methyl methacrylate and ethyl methacrylate; alkyl acrylates such as methyl acrylate, ethyl acrylate, and butyl acrylate; and maleimide compounds such as N-phenylmaleimide and N-cyclohexylmaleimide. The other vinyl compound (a3) ​​is preferably a vinyl compound that does not contain acidic groups (e.g., carboxyl groups, phosphate groups, sulfonic acid groups, etc.) and epoxy groups (including glycidyl groups). Other vinyl compounds (a3) ​​may be used individually or in combination of two or more.

[0032] Preferably, the proportions of each vinyl compound in monomer component (a) are 60-80% by mass of aromatic vinyl compound (a1), 20-40% by mass of vinyl cyanide compound (a2), and 0-20% by mass of other vinyl compounds (a3), relative to the total mass of monomer component (a). If the proportions of each compound are within the above range, the moldability and mechanical property balance of the polycarbonate resin composition will be improved.

[0033] (Rubber content (X)) The ratio of the rubbery polymer to the total mass of the graft copolymer (A) in this embodiment is referred to as the "rubber content (X) in the graft copolymer (A)". Preferably, the ratio of the rubbery polymer to monomer component (a) is such that the rubbery polymer is more than 40% by mass and the monomer component (a) is less than 60% by mass relative to the total mass of the graft copolymer (A). If the ratio of the rubbery polymer to monomer component (a) is within the above range, the mechanical properties and the impact resistance of the molded product will be improved.

[0034] The proportion of the rubbery polymer (rubber content (X)) is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass, relative to the total mass of the graft copolymer (A). Furthermore, the proportion of the rubbery polymer is preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less, relative to the total mass of the graft copolymer (A). In other words, the proportion of the rubbery polymer is preferably more than 20% by mass and 80% by mass or less, more preferably 25 to 75% by mass, and even more preferably 25 to 70% by mass and 30 to 70% by mass, relative to the total mass of the graft copolymer (A).

[0035] The proportion of monomer component (a) is preferably 20% by mass or more and less than 80% by mass, more preferably 25-75% by mass, and even more preferably 30-75% by mass and 30-70% by mass, relative to the total mass of the graft copolymer (A). The total mass of monomer component (a) and the rubbery polymer is approximately equal to the total mass of the graft copolymer (A).

[0036] <Method for producing graft copolymer (A)> Graft copolymer (A) is obtained by polymerizing monomer component (a) in the presence of a rubbery polymer (graft polymerization). The graft copolymer (A) obtained in this way has a form in which a vinyl copolymer obtained by polymerizing monomer component (a) is grafted onto a rubbery polymer.

[0037] While there are no particular restrictions on the method of graft polymerization, emulsion polymerization is preferred because it allows for controllable and stable reaction progress. Specifically, examples include a method in which monomer component (a) is charged all at once into the latex of a rubbery polymer and then polymerized; a method in which a portion of monomer component (a) is charged first into the latex of a rubbery polymer, and the remainder is added dropwise to the polymerization system while polymerization proceeds as needed; and a method in which the entire amount of monomer component (a) is added dropwise into the latex of a rubbery polymer while polymerization proceeds as needed. Polymerization of monomer component (a) may be carried out in one step or in two or more steps. When carried out in two or more steps, it is also possible to change the type and composition ratio of the vinyl compound constituting monomer component (a) in each step. The graft copolymer (A) obtained by emulsion polymerization is usually in the form of latex. Polymerization conditions may be, for example, 30-95°C for 1-10 hours. Emulsion polymerization typically involves the use of polymerization initiators, chain transfer agents (molecular weight modifiers), and emulsifiers.

[0038] Examples of polymerization initiators include redox initiators combining organic peroxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, and paramenthane hydroperoxide with reducing agents such as sugar pyrophosphate and sulfoxylate; persulfates such as potassium persulfate; and peroxides such as benzoyl peroxide (BPO), azobisisobutyronitrile, lauroyl peroxide, tert-butyl peroxylaurate, and tert-butyl peroxymonocarbonate. Polymerization initiators may be oil-soluble or water-soluble, and may also be used in combination. These polymerization initiators may be used individually or in combination of two or more. The polymerization initiator can be added to the latex of the rubbery polymer all at once or sequentially. The amount of polymerization initiator used is preferably 0.05 to 0.25 parts by mass, and more preferably 0.08 to 0.2 parts by mass, per 100 parts by mass of the total of the rubbery polymer and monomer component (a).

[0039] Examples of chain transfer agents include mercaptans such as octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, n-hexamethyl mercaptan, n-tetradecyl mercaptan, and tert-tetradecyl mercaptan; terpinolenes; and dimers of α-methylstyrene. These chain transfer agents may be used individually or in combination of two or more. The chain transfer agent can be added to the latex of the rubbery polymer all at once or continuously. The amount of chain transfer agent used is preferably 0.1 to 0.3 parts by mass, and more preferably 0.1 to 0.2 parts by mass, per 100 parts by mass of the total of the rubbery polymer and monomer component (a).

[0040] Examples of emulsifiers include sodium sarcosinate, potassium fatty acid, sodium fatty acid, dipotassium alkenylsuccinate, calcium rosinate, disproportionate calcium rosinate, carboxylates, alkylbenzene sulfonates, and others. These emulsifiers may be used individually or in combination of two or more. The amount of emulsifier used is preferably 0.1 to 0.4 parts by mass, and more preferably 0.1 to 0.3 parts by mass, per 100 parts by mass of the total of the rubbery polymer and monomer component (a).

[0041] Graft copolymer (A) is usually obtained in latex form. Methods for recovering graft copolymer (A) from the latex include, for example, a wet method in which the latex of graft copolymer (A) is immersed in hot water containing a coagulant to coagulate it into a slurry; and a spray-drying method in which the graft copolymer (A) is recovered semi-directly by spraying the latex of graft copolymer (A) into a heated atmosphere.

[0042] Examples of coagulants used in the wet process include inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, and nitric acid; and metal salts such as calcium chloride, calcium acetate, and aluminum sulfate, which are selected according to the emulsifier used in polymerization. For example, if only carboxylate salts are used as emulsifiers, one or more of the above-mentioned coagulants can be used. When an emulsifier that exhibits stable emulsifying power even in the acidic range, such as sodium alkylbenzenesulfonate, is used as the emulsifier, metal salts are preferred as coagulants.

[0043] Using a wet process, a slurry-like graft copolymer (A) can be obtained. Methods for obtaining a dry graft copolymer (A) from this slurry-like graft copolymer (A) include first dissolving any remaining emulsifier residue in water and washing it, then dewatering the slurry using a centrifugal or press dewatering machine, and finally drying it in an air-flow dryer; or performing dewatering and drying simultaneously using a press dewatering machine or extruder. By such methods, a powdered or particulate dry graft copolymer (A) can be obtained. While there are no particular restrictions on the washing conditions, it is preferable to wash under conditions such that the amount of emulsifier residue contained in 100% by mass of the dried graft copolymer (A) is 2% by mass or less, more preferably 0.5% by mass or less. If a large amount of emulsifier residue remains, it can cause thermal decomposition of the polycarbonate resin. Furthermore, it is also possible to send the graft copolymer (A) discharged from the press dewatering machine or extruder directly to an extruder or molding machine that manufactures resin compositions, without recovering it, to produce molded products.

[0044] <Copolymer (B)> Copolymer (B) is obtained by copolymerizing an aromatic vinyl compound (b1), a vinyl cyanide compound (b2), and optionally another monovinyl compound (b3). That is, copolymer (B) is a copolymer having monomer units derived from the aromatic vinyl compound (b1), monomer units derived from the vinyl cyanide compound (b2), and optionally monomer units derived from another monovinyl compound (b3). Unlike graft copolymer (A), copolymer (B) is not grafted onto a rubbery polymer.

[0045] In copolymer (B), the aromatic vinyl compound (b1), vinyl cyanide compound (b2), and other vinyl compounds (b3) used as needed can be the same compounds as the aromatic vinyl compound (a1), vinyl cyanide compound (a2), and other vinyl compounds (a3) ​​exemplified earlier in the description of graft copolymer (A), and the preferred embodiments are also the same. In addition to the examples given above, other vinyl compounds (a3) ​​that form copolymer (B) may be unsaturated carboxylic acid compounds such as (meth)acrylic acid, itaconic acid, and fumaric acid.

[0046] The content of monomer units derived from the aromatic vinyl compound (b1) in copolymer (B) is not particularly limited, but is preferably 50 to 80% by mass relative to the total mass of copolymer (B). The content of monomer units derived from vinyl cyanide compound (b2) in copolymer (B) is not particularly limited, but is preferably 20 to 50% by mass relative to the total mass of copolymer (B). The content of monomer units derived from other vinyl compounds (b3) in copolymer (B) is not particularly limited, but is preferably 0 to 20% by mass relative to the total mass of copolymer (B). The mass-average molecular weight of copolymer (B) is preferably, for example, 50,000 to 150,000. The mass-average molecular weight of copolymer (B) is a value on a standard polystyrene basis, measured using gel permeation chromatography (GPC). Copolymer (B) can be produced by copolymerizing an aromatic vinyl compound (b1), a vinyl cyanide compound (b2), and, if necessary, another vinyl compound (b3). Any known polymerization method can be applied, such as emulsion polymerization, suspension polymerization, bulk polymerization, or a combination thereof.

[0047] <Matte finish agent (M)> The antistatic effect of the present invention is even more easily obtained in applications of molded products with a matte finish. This is because the matte finish is achieved by using a matting agent to create fine irregularities on the surface of the molded product, which causes light to scatter. These fine irregularities make it more difficult to remove dust. Examples of matting agents (M) include organic matting agents such as acid-modified rubber, epoxy-modified rubber, amorphous diene rubber obtained by the vulcanization reaction of styrene-conjugated diene rubber block copolymer and conjugated diene rubber, and crosslinked particles remaining as gels after melt kneading (e.g., acrylic crosslinked particles). Examples of acid-modified rubber include acid-modified styrene resins. Examples of epoxy-modified rubber include epoxy-modified styrene resins. Here, "acid group modification" refers to the introduction of acid groups (such as carboxyl groups, phosphate groups, sulfonic acid groups, etc.) into rubber or resin, while "epoxy modification" refers to the introduction of epoxy groups into rubber or resin. Furthermore, examples of matting agents (M) include inorganic matting agents such as silica, calcium carbonate, calcium phosphate, titanium dioxide, carbon fiber, and glass fiber. These matting agents (M) may be used individually or in combination of two or more types. In this embodiment, among the matting agents (M), the organic matting agent is treated as being included as part of the main resin raw material of the rubber-reinforced resin (G).

[0048] <Antistatic agent (E)> Generally, antistatic agents are classified either by molecular weight or by the presence or type of charge (nonionic, cationic, anionic, amphoteric). Here, those with a number average molecular weight of 2000 or more are classified as high molecular weight antistatic agents, and those with a number average molecular weight of less than that are classified as low molecular weight antistatic agents.

[0049] Examples of polymeric antistatic agents include block copolymers having hydrophilic groups. Specifically, these include polyethers classified into nonionic, anionic, and cationic types. Examples of nonionic types include polyether ester amides, ethylene oxide-epicrohydrins, and polyether esters. Examples of anionic types include polystyrene sulfonic acids. Examples of cationic types include quaternary ammonium-containing poly(meth)acrylates.

[0050] The structure of the block copolymer includes a structure in which a polyether block and a polyolefin block are repeatedly and alternately bonded together via at least one type of bond selected from ester bonds, amide bonds, ether bonds, urethane bonds, and imide bonds. As an example, a structure with a volume resistivity of 10 5 ~10 11 Examples include block copolymers in which polyether blocks, which are hydrophilic blocks with a density of Ω·cm, and polyolefin blocks are repeatedly and alternately bonded together. The number-average molecular weight (Mn) of the block copolymer is preferably between 2,000 and 60,000. The aforementioned block copolymer is different from graft copolymer (A) and copolymer (B).

[0051] Examples of antistatic agents (E), from a perspective other than molecular weight, include polyethylene glycol-type nonionic surfactants, polyhydric alcohol-type nonionic surfactants, anionic surfactants, cationic surfactants, amino acid-type amphoteric surfactants, betaine-type amphoteric surfactants, and ion-conducting polymers.

[0052] Sankonol®, a registered trademark manufactured by Sanko Chemical Industry Co., Ltd., is an example of an ion-conducting polymer. It is a polymeric antistatic agent with polyether bonds, in which cations (e.g., lithium ions) are held by the oxygen atoms of the polyether block. When an external electric field is applied, the cations incorporated into the polyether move (ion transport) due to the molecular motion of the ether oxygen, exhibiting an antistatic effect.

[0053] In this embodiment, it is preferable to use a high molecular weight antistatic agent, and more preferably an ion-conducting polymer, from the viewpoint of thermal stability during melt mixing and injection molding, and the mechanical properties of the resin composition. The antistatic agent (E) can be used alone or in combination of two or more types.

[0054] <Alkyl phosphate (F)> Alkyl phosphate (F) is represented by formula (2). (HO) n -(O=)P-(OR) 3-n ...(2) In the formula, n represents 1 or 2, and R represents an alkyl group. The number of carbon atoms in the alkyl group of R is preferably in the order of 1-30, 4-30, 4-20, 8-20, and 10-20. Among these, alkyl groups with 10 or more carbon atoms are preferred, and an octadecyl group with 18 carbon atoms is particularly preferred. The alkyl group of R can be linear or branched, with linear being preferred. The alkyl phosphate (F) contained in the polycarbonate resin composition of this embodiment may be one type or two or more types. For example, structures with a value of n of 1 or 2 in formula (2) may be used individually, or a mixture thereof may be used.

[0055] <Other ingredients> Other components include various additives and other resins. Examples of additives include known antioxidants, light stabilizers, UV absorbers, lubricants, plasticizers, stabilizers, mold release agents, colorants (pigments, dyes, etc.), flame retardants such as brominated flame retardants and phosphorus-based flame retardants, flame retardant aids such as antimony trioxide, drip inhibitors such as fluororesins, antibacterial agents, antifungal agents, silicone oil, coupling agents, and matting agents such as carbon fiber, glass fiber, wollastonite, calcium carbonate, silica, and talc, which are used as fillers. These additives may be used individually or in combination of two or more.

[0056] Other resins include those other than the graft copolymer (A), copolymer (B), matting agent (M), and antistatic agent (E) mentioned above. Examples include polystyrene resin, nylon resin, methacrylic resin, polyvinyl chloride resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyphenylene ether resin, and these resins modified with compatibilizers or functional groups. These other resins may be used individually or in combination of two or more types.

[0057] Furthermore, any essential or optional components used in this invention can be recycled materials recovered during polymerization, processing, or molding, or collected from the market, provided they do not pose any quality issues.

[0058] <Content of each ingredient> The content of rubber-reinforced resin (G) is preferably 30 to 60 parts by mass, more preferably 35 to 55 parts by mass, and even more preferably 40 to 50 parts by mass, based on 100 parts by weight of the total resin main raw materials consisting of polycarbonate resin (P) and rubber-reinforced resin (G) (which may also contain an organic matting agent). If the content of rubber-reinforced resin (G) is above the lower limit, the impact resistance of the molded product is improved, and if it is below the upper limit, the fluidity of the polycarbonate resin composition during molding is improved.

[0059] There are no specific restrictions on the amount of matting agent (M) that can be used. This is because the degree of matting effect obtained varies depending on the type of matting agent used, and the amount used will also vary depending on the desired level of matte finish. When the matting agent (M) is an organic matting agent, its content is counted as part of the elements constituting the rubber-reinforced resin (G), and examples include 0.5 to 40 parts by mass, 1 to 40 parts by mass, 3 to 35 parts by mass, 5 to 30 parts by mass, 10 to 25 parts by mass, 5 to 25 parts by mass, etc., per 100 parts by weight of the total resin main raw materials consisting of polycarbonate resin (P) and rubber-reinforced resin (G). When using two or more types of organic matting agents (M), the total amount can be within the above range. When the matting agent (M) is an inorganic matting agent, its content is not counted as part of the elements constituting the rubber-reinforced resin (G). Examples of the amount of the matting agent include 0.5 to 30 parts by mass, 1 to 30 parts by mass, 3 to 25 parts by mass, 5 to 20 parts by mass, 10 to 15 parts by mass, 5 to 15 parts by mass, etc., per 100 parts by weight of the total resin main raw materials consisting of polycarbonate resin (P) and rubber-reinforced resin (G). When using two or more types of inorganic matting agents (M), the total amount can be within the above range. Additionally, organic and inorganic matting agents (M) may be used in combination.

[0060] There are no particular restrictions on the amount of antistatic agent (E) that can be contained. As a guideline, for every 100 parts by weight of the main resin raw material consisting of polycarbonate resin (P) and rubber-reinforced resin (G) (which may contain an organic matting agent), the amount can be, for example, 0.1 to 20 parts by weight, 0.5 to 15 parts by weight, 1 to 10 parts by weight, 2 to 8 parts by weight, 3 to 6 parts by weight, etc. When using two or more types of antistatic agents (E), their total amount can be within the above range.

[0061] The content of alkyl phosphate (F) is not particularly limited, but from the viewpoint of improving the heat decomposition resistance of the polycarbonate resin composition, it is preferable, for example, 0.05 to 2 parts by mass, and more preferably 0.1 to 1.5 parts by mass, per 100 parts by weight of the total resin main raw materials consisting of polycarbonate resin (P) and rubber-reinforced resin (G) (which may contain an organic matting agent).

[0062] The content of alkyl phosphate (F) is preferably 1 to 100 parts by mass, more preferably 5 to 50 parts by mass, and even more preferably 10 to 30 parts by mass, per 100 parts by mass of the antistatic agent (E). Within this preferred range, the heat decomposition resistance (appearance of the molded product) is further improved.

[0063] As an example of a preferred composition of the polycarbonate resin composition of this embodiment, the following composition is given: a composition in which, based on the total mass of the polycarbonate resin composition, the content of polycarbonate resin (P) is 40 to 80% by mass, the content of rubber-reinforced resin (G) other than organic matting agents is 15 to 30% by mass, the content of organic matting agents (M) is 1 to 25% by mass, the content of antistatic agents (E) is 0.1 to 15% by mass, and the content of alkyl phosphate (F) is 0.01 to 5% by mass.

[0064] A more preferred composition is one in which, relative to the total mass, the polycarbonate resin (P) content is 45 to 70% by mass, the rubber-reinforced resin (G) content other than the organic matting agent is 20 to 30% by mass, the organic matting agent (M) content is 5 to 25% by mass, the antistatic agent (E) content is 0.1 to 10% by mass, and the alkyl phosphate (F) content is 0.05 to 2% by mass.

[0065] A more preferred composition is one in which, relative to the total mass, the polycarbonate resin (P) content is 50-60% by mass, the rubber-reinforced resin (G) content other than the organic matting agent is 20-30% by mass, the organic matting agent (M) content is 10-25% by mass, the antistatic agent (E) content is 0.1-10% by mass, and the alkyl phosphate (F) content is 0.1-1% by mass.

[0066] In each of the above preferred compositions, the organic matting agent (M) preferably contains an epoxy-modified styrene resin. In each of the above preferred compositions, the antistatic agent (E) preferably contains an ion-conducting polymer. In each of the above preferred compositions, it is preferable that the alkyl phosphate (F) includes the one described in formula (2). In each of the above preferred compositions, the rubber-reinforced resin (G) preferably comprises a graft copolymer (A) and a copolymer (B). Here, the graft copolymer (A) is formed by a rubbery polymer and graft chains bonded to the rubbery polymer, the proportion of the rubbery polymer to the total mass of the graft copolymer (A) is more than 20% by mass and 80% by mass or less, the proportion of monomer components (a) constituting the graft chains is 20% by mass or more and less than 80% by mass, and the sum of the proportion of the rubbery polymer and the proportion of monomer components (a) is 100% by mass. Furthermore, the content of monomer units derived from aromatic vinyl compound (b1) in copolymer (B) is preferably 50 to 80% by mass relative to the total mass of copolymer (B).

[0067] <Physical properties of polycarbonate resin compositions> In accordance with ISO 179, the Charpy impact strength (test specimen shape: Type B, notch shape A) of the polycarbonate resin composition of this embodiment was measured at a measurement temperature of 23°C (unit: kJ / m²). 2 For example, a value of 30 or higher is preferred, 35 or higher is more preferred, 40 or higher is even more preferred, 45 or higher is particularly preferred, and 50 or higher is most preferred. As a guideline for the upper limit, for example, 80 or lower is given.

[0068] The melt mass flow rate (MFR) of the polycarbonate resin composition in this embodiment, measured in accordance with ISO 1133 under conditions of a measurement temperature of 240°C and a load of 98N (unit: g / 10 min), is preferably 40 or less, more preferably 30 or less, even more preferably 25 or less, particularly preferably 20 or less, and most preferably 15 or less. A guideline for the lower limit is, for example, 1 or more. Within the above preferred range, injection molding becomes easier and the appearance of the injection molded product is further improved.

[0069] In accordance with ISO 2813, the gloss value at any position on the surface of a molded article made of the polycarbonate resin composition of this embodiment is measured with a gloss meter, and the value (dimensionless number) of the reflected light at an incident angle of 60° is preferably 60 or less, more preferably 55 or less, even more preferably 50 or less, particularly preferably 45 or less, and most preferably 40 or less. A guideline for the lower limit is, for example, 1 or more. If it is within the above preferred range, the molded article will have less gloss and a superior matte appearance. Furthermore, ISO 2813 defines the gloss value as the ratio of the luminous flux reflected from an object in the mirror direction at a specified angle of light source and receiver to the luminous flux reflected in the mirror direction from glass with a refractive index of 1.567. To clarify the standard for specular gloss, polished black glass with a refractive index of 1.567 has a gloss value of 100 defined for geometric conditions of 20°, 60°, and 85°.

[0070] <Method for producing polycarbonate resin composition> The polycarbonate resin composition of the first embodiment can be produced, for example, by mixing and kneading a mixture of polycarbonate resin (P), rubber-reinforced resin (G), and optionally a matting agent (M) with an antistatic agent (E), alkyl phosphate (F), and optionally one or more other components. There are no particular restrictions on the method of mixing and kneading each component; any general mixing and kneading method may be used. For example, one method involves kneading the mixture using an extruder, Banbury mixer, kneading rolls, etc., and then cutting it into pellets using a pelletizer, etc. The polycarbonate resin composition of the first embodiment can be molded into a molded article.

[0071] ≪Molded products≫ A second aspect of the present invention is a molded article obtained by molding the polycarbonate resin composition of the first aspect or a material containing the same. The molded article of this embodiment can be obtained by molding the polycarbonate resin composition of the first embodiment or a material containing the same using a known molding method. Examples of molding methods include injection molding, press molding, extrusion molding, vacuum molding, blow molding, and the like.

[0072] The polycarbonate resin composition of the first embodiment is preferable for use in injection molding because it has excellent thermal decomposition resistance and can suppress the occurrence of silver streaks. In other words, the molded product of this embodiment is preferably an injection molded product. The melting temperature (residence temperature in the cylinder) of the polycarbonate resin composition during injection molding can be 200°C or higher, and can also be 250 to 280°C. [Examples]

[0073] In the following, unless otherwise specified, "parts" and "%" refer to "parts by mass" and "% by mass," respectively.

[0074] [Polycarbonate resin (P)] Polycarbonate resin (P-1): "Novarex 7022PJ" manufactured by Mitsubishi Engineering Plastics Corporation (viscosity-average molecular weight (Mv): 21,000) was used. This polycarbonate resin was synthesized using bisphenol A.

[0075] [Production of graft copolymer (A) and copolymer (B)]

[0076] <Synthesis Example 1: Production of rubbery polymer (g-1)> 150 parts water, 3.3 parts potassium tallow fatty acid salt, 0.14 parts potassium hydroxide, 0.3 parts sodium pyrophosphate, and 0.20 parts tert-dodecyl mercaptan were charged into the reactor, followed by 100 parts 1,3-butadiene, and the temperature was raised to 62°C. Next, 0.12 parts potassium persulfate was injected under pressure to start polymerization. The reaction was carried out over 10 hours, reaching 75°C. After further reaction at 75°C for 1 hour, 0.08 parts sodium formaldehyde sulfoxylate was injected under pressure. After removing the remaining 1,3-butadiene, the polymer was taken out. A latex polymer (with a solid content of 35%) was obtained. The volume-average particle size of the obtained polymer polymer was 0.08 μm. To 100 parts (solids) of the obtained rubbery polymer latex, 2 parts (solids) of copolymer latex (average particle size 0.11 μm) consisting of 85% n-butyl acrylate units and 15% methacrylic acid units was added while stirring, and stirring was continued for 30 minutes to obtain latex of an enlarged butadiene-based rubbery polymer (g-1) with an average particle size 0.28 μm.

[0077] <Synthesis Example 2: Production of Graft Copolymer (A-1)> In a closed reactor equipped with a reagent injection container, condenser, nitrogen purging device, jacket heater, and stirrer, 180 parts water (including water in the latex of the rubbery polymer (g)), 70 parts of the latex of the rubbery polymer (g) on ​​a solid content basis, and 0.13 parts of disproportionated potassium rosinate were added. The internal temperature of the reactor was raised to 55°C while purging with nitrogen and maintained for 30 minutes. Then, a solution of 0.15 parts sodium pyrophosphate, 0.008 parts ferrous sulfate heptahydrate, and 0.3 parts glucose dissolved in 8 parts deionized water was added. Next, a mixture of 7.5 parts acrylonitrile, 22.5 parts styrene, 0.07 parts cumene hydroperoxide, and 0.09 parts tert-dodecyl mercaptan was added dropwise over 5 hours to polymerize. After the dropwise addition was complete, the mixture was stirred for 30 minutes while maintaining the internal temperature at 55°C, and then cooled to obtain graft copolymer latex. The obtained graft copolymer latex was diluted 1.25 times with distilled water and gradually added dropwise to a 3% sulfuric acid aqueous solution at 50°C. After the entire volume had been added, the temperature was raised to 90°C and held for 5 minutes to allow it to solidify. The solidified material was then centrifuged using a filter cloth, and the wet powder-like graft copolymer was dried to obtain graft copolymer (A-1). The rubber content (X) of the obtained graft copolymer (A-1: ABS resin) was 70% by mass, and the grafting rate (Y) was 38.6%. In this embodiment, the amount of rubbery polymer (g) added was defined as the rubber content (X).

[0078] The graft rate can be calculated using the following formula. Graft rate (mass%) = {(TS) / S} × 100 In the above formula, T is the mass (g) of the insoluble matter obtained by separating the insoluble matter from the soluble matter by adding 1g of graft copolymer (A-1) to 20ml of acetone, shaking with a shaker for 2 hours, and then centrifuging with a centrifuge (rotation speed: 23,000 rpm) for 60 minutes, and S is the mass (g) of the rubbery polymer contained in 1g of graft copolymer (A-1). If only an aromatic vinyl compound is used as monomer component (a), methyl ethyl ketone is used instead of acetone for measurement.

[0079] <Synthesis Example 3: Production of Graft Copolymer (A-2)> In a 20-liter stainless steel autoclave equipped with ribbon-type agitator blades, a continuous additive addition device, and a thermometer, 22 parts of ethylene-propylene copolymer (ethylene / propylene = 78 / 22 (%), Mooney viscosity (ML1 + 4, 100℃) 20, melting point (Tm) 40℃, glass transition temperature (Tg) -50℃), 55 parts of styrene, 23 parts of acrylonitrile, 0.5 parts of t-dodecyl mercaptan, and 110 parts of toluene were charged. The internal temperature was raised to 75℃, and the contents of the autoclave were stirred for 1 hour to obtain a homogeneous solution. Subsequently, 0.45 parts of t-butyl peroxyisopropyl monocarbonate were added, and the internal temperature was further raised until it reached 100℃. After that, the polymerization reaction was carried out while maintaining this temperature and stirring speed at 100 rpm. Four hours after the start of the polymerization reaction, the internal temperature was raised to 120°C, and the reaction was carried out for another 2 hours while maintaining this temperature to complete the polymerization reaction. After that, the internal temperature was cooled to 100°C, and 0.2 parts of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenol)-propionate and 0.02 parts of dimethyl silicone oil; KF-96-100cSt (product name: Shin-Etsu Silicone Co., Ltd.) were added. The reaction mixture was then removed from the autoclave, unreacted products and solvent were removed by steam distillation, and volatile components were substantially degassed using a 40 mmφ vented extruder (cylinder temperature 220°C, vacuum 760 mmHg) to form pellets. The resulting graft copolymer (A-2: AES resin) had a rubber content of 30% by mass, an acrylonitrile content of graft chains of 25% by mass, a grafting rate of 60%, and an intrinsic viscosity [η] of acetone-soluble components of 0.47 dl / g.

[0080] [Production of copolymer (B)] <Synthesis example 4: Copolymer (B-1)> A monomer mixture consisting of 125 parts water, 0.4 parts calcium phosphate, 0.003 parts potassium alkenylsuccinate, 0.05 parts 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 0.04 parts 1,1-di(tert-hexylperoxy)cyclohexane, 0.04 parts tert-butyl peroxy-2-ethylhexyl carbonate, 0.45 parts tert-dodecyl mercaptan, 26 parts acrylonitrile, and 74 parts styrene was charged into a reactor and reacted. The reaction was carried out by sequentially adding water, acrylonitrile, and a portion of the styrene, heating from a starting temperature of 65°C for 6.5 hours, and then reaching 125°C. After further reaction at 125°C for 1 hour, a slurry of copolymer (B-1) was obtained. After cooling, this slurry was centrifuged to dehydrate it and obtain copolymer (B-1). The mass-average molecular weight of the obtained copolymer (B-1: AS resin) was 114,000.

[0081] [Matte finish agent (M)] <Synthesis Example 5: Synthesis of Matting Agent (M-1)> In a polymerizer equipped with a stirrer, 280 parts of water and 60 parts (on a solids basis) of polybutadiene latex with a volume-average particle size of 0.26 μm and a gel fraction of 90% were charged. The mixture consisted of 0.3 parts sodium formaldehyde sulfoxylate, 0.0025 parts ferrous sulfate, and 0.01 parts disodium ethylenediaminetetraacetate. After deoxygenation, the mixture was heated to 60°C while stirring under a nitrogen atmosphere. A monomer mixture consisting of 9 parts acrylonitrile, 27 parts styrene, 4 parts glycidyl methacrylate (GMA), 0.2 parts t-dodecyl mercaptan, and 0.3 parts cumene hydroperoxide was then continuously added dropwise at 60°C for 5 hours. After the addition was complete, the polymerization temperature was increased to 65°C, and stirring was continued for 1 hour. Polymerization was then terminated to obtain a graft copolymer latex in which the epoxy-modified styrene copolymer was grafted onto the diene-based rubber polymer. The polymerization conversion rate was 98%. This latex was subjected to sulfuric acid precipitation to remove solid components, followed by washing, dehydration, and drying to obtain a powdered matting agent (M-1).

[0082] Matting agent (M-2): Zeon Chemicals' matting agent "Revital Matte Ace AM-808" (product name) (a amorphous diene rubber modified copolymer resin obtained by the vulcanization reaction of styrene-conjugated diene rubber block copolymer and conjugated diene rubber) was used.

[0083] [Manufacturing of rubber-reinforced resin (G)] The graft copolymers (A-1), (A-2), copolymer (B) produced above, and a matting agent (M) were mixed in the formulations shown in Tables 1 and 2 to obtain rubber-reinforced resin (G).

[0084] [Antistatic agent (E)] Antistatic agent (E-1): Sankonol TBX-65 (ion-conducting polymer, lithium ion-containing) manufactured by Sanko Chemical Industry Co., Ltd. was used.

[0085] [Alkyl phosphate (F)] The following alkyl phosphates (F) were prepared and used. F-1: ADEKA Corporation's ADEKA stub AX-71 (octadecyl phosphate, alkyl group with 18 carbon atoms) F-2: JAMP-8EH (mono(2-ethylhexyl) phosphate, alkyl group with 8 carbon atoms) manufactured by Johoku Chemical Industry Co., Ltd.

[0086] A carbodiimide compound known as a hydrolysis inhibitor, Stavaxol P100 manufactured by LANXESS, was used.

[0087] <Method for measuring volume-average particle diameter> In the above synthesis example, the volume-average particle size (MV) of the rubbery polymer was measured using a Microtrac (Nanotrac 150, manufactured by Nikkiso Co., Ltd.) based on dynamic scattering theory, with pure water as the measurement solvent. Furthermore, image analysis using an electron microscope confirmed that the volume-average particle size of the rubbery polymer directly reflects the volume-average particle size of the rubbery polymer in the graft copolymer and polycarbonate resin composition.

[0088] [Examples 1-9, Comparative Examples 1-14] Polycarbonate resin compositions were prepared by mixing each raw material in the proportions (parts by mass) shown in Tables 1 and 2. The obtained polycarbonate resin compositions were melt-kneaded at a temperature of 260°C using a 30 mm twin-screw extruder (TEX30α, manufactured by Japan Steel Works Ltd.) to form pellets of the polycarbonate resin compositions to be used in the following tests. Examples 1、 Numbers 9-14 are examples.

[0089] <Measurement of Charpy impact strength> Pellets of polycarbonate resin composition were injection molded using an 80-ton injection molding machine (Japan Steel Works Ltd., "J80ADS-110U") to obtain test specimens (80 mm long x 10 mm wide x 4 mm thick). Injection molding was performed under the following conditions: molding temperature 250°C, mold temperature 60°C, and injection speed 42 mm / sec. The Charpy impact strength (with notch) of the obtained test specimens was measured in accordance with ISO 179 at a measurement temperature of 23°C. When comparing this value with the measured values ​​of other polycarbonate resins, using the measured values ​​of Comparative Examples 1 and 2, which did not contain the antistatic agent (E) and alkyl phosphate (F), as a baseline, it was determined that the less change (smaller the difference), the more suppressed the thermal decomposition of the compared polycarbonate resin.

[0090] <mfr> In accordance with ISO 1133, the melt mass flow rate (in g / 10 min) of each polycarbonate resin composition was measured under conditions of a temperature of 240°C and a load of 98 N. When comparing the MFR of the other polycarbonate resins to that of Comparative Examples 1 and 2, which did not contain antistatic agents (E) and alkyl phosphates (F), a smaller change (smaller difference) was considered to indicate that the thermal decomposition of the compared polycarbonate resin was suppressed.

[0091] <Evaluation of matte finish> Each polycarbonate resin composition was injection molded using a Toshiba Machine IS-170FA injection molding machine at a cylinder temperature of 260°C, injection pressure of 50 MPa, mold temperature of 60°C, and a rate of 20 mm / s to obtain injection-molded plates (tray lids) measuring 270 mm in length, 200 mm in width, and 3 mm in thickness. The reflected light from the center of the molded product at an incident angle of 60° was measured using a Nippon Denshoku Industries Ltd. GlossMeter VG7000 digital angle-shifting gloss meter, and the product was judged according to the following criteria. ○: Excellent gloss value of 40 or less. △: Practical if gloss value is between 40 and 60. ×: It is difficult to achieve a matte finish when the gloss value exceeds 60.

[0092] <Molded appearance evaluation> Each polycarbonate resin composition was injected using a NEX1804-36E injection molding machine manufactured by Nissei Plastic Industrial Co., Ltd., after being held in the cylinder at a temperature of 270°C for 5 minutes. The injection molding was then performed at an injection pressure of 40 MPa, a mold temperature of 60°C, and a rate of 15 mm / s to obtain injection-molded plates (FMVSS test plates) measuring 350 mm in length, 100 mm in width, and 2 mm in thickness. The presence or absence of silver streaks was visually confirmed, and the results were judged according to the following criteria. A: Silverstreak is not available. B: Silverstreak can be seen in 1 to 5 locations. C: Silverstreak can be seen in 6-12 locations. D: Silverstreak can be seen in 13 or more locations.

[0093] <Evaluation of dust adhesion> Each polycarbonate resin composition was injection molded using a Toshiba Machine IS-170FA injection molding machine at a cylinder temperature of 260°C, injection pressure of 50 MPa, mold temperature of 60°C, and a speed of 20 mm / s to obtain test specimens measuring 270 mm in length, 200 mm in width, and 3 mm in thickness. Following the ASTM D2741 test procedure, the test specimens were placed in a dirt chamber test apparatus adjusted to a temperature of 23°C and humidity of 65% for 24 hours, after which a test was conducted in which 3 g of carbon black was circulated and blown for 5 minutes. The test specimens were visually inspected after the test and evaluated according to the following evaluation criteria. A score of △ or higher in the dirt chamber test was considered to indicate dust adhesion prevention. ○: A small amount of carbon black is evenly distributed, or none is present at all. △: Carbon black is applied uniformly and in slightly excessive amounts, or there is a slight floral pattern (uneven application). ×: Carbon black is unevenly applied throughout.

[0094] The polycarbonate resin compositions of the examples according to the present invention exhibited excellent molded appearance and dust adhesion. In particular, Examples 1 to 7, which contained alkyl phosphates having alkyl groups with 10 or more carbon atoms, showed exceptionally outstanding molded appearance. On the other hand, Comparative Examples 1-3, which did not contain the antistatic agent (E) and alkyl phosphate (F), exhibited poor dust adhesion. Furthermore, Comparative Examples 4-8, which did not contain alkyl phosphate (F), had poor molded appearance. In addition, Comparative Example 9, which contained a carbodiimide compound instead of alkyl phosphate (F), had poor molded appearance and failed to suppress thermal decomposition.

[0095] [Table 1]

[0096] [Table 2] < / mfr>

Claims

1. The polycarbonate resin composition comprises a resin main raw material including a polycarbonate resin (P) and a rubber-reinforced resin (G) composition, an antistatic agent (E), and an alkyl phosphate (F). The rubber-reinforced resin (G) composition comprises a graft copolymer (A), a copolymer (B), and an organic matting agent (M) different from the graft copolymer (A) and the copolymer (B). The polycarbonate resin (P) content is 50 to 60% by mass of the total mass of the polycarbonate resin composition, the rubber-reinforced resin (G) composition other than the organic matting agent (M) content is 20 to 30% by mass, the organic matting agent (M) content is 10 to 25% by mass, the antistatic agent (E) content is 0.1 to 10% by mass, and the alkyl phosphate (F) content is 0.1 to 1% by mass. The graft copolymer (A) is formed by a rubbery polymer and graft chains bonded to the rubbery polymer. With respect to the total mass of the graft copolymer (A), the proportion of the rubbery polymer is greater than 20% by mass and 80% by mass or less, the proportion of monomer components (a) constituting the graft chain is 20% by mass or more and less than 80% by mass, and the sum of the proportion of the rubbery polymer and the proportion of monomer components (a) is 100% by mass. The content of monomer units derived from the aromatic vinyl compound (b1) in the copolymer (B) is 50 to 80% by mass relative to the total mass of the copolymer (B). The antistatic agent (E) comprises an ion-conducting polymer, The alkyl phosphate (F) is represented by the following formula (2), where the alkyl group represented by R in the following formula (2) has 10 to 20 carbon atoms. A polycarbonate resin composition comprising 0.1 to 20 parts by mass of the antistatic agent (E) and 0.1 to 1.5 parts by mass of the alkyl phosphate (F) per 100 parts by mass of the total of the polycarbonate resin (P) and the rubber-reinforced resin (G) composition. (HO) ｎ -(O=)P-(O-R) ３－ｎ ・・・(2) (However, in formula (2), n represents 1 or 2, and R represents an alkyl group.)

2. The polycarbonate resin composition according to claim 1, wherein the organic matting agent (M) comprises one or more selected from acid-modified rubber, epoxy-modified rubber, and amorphous diene rubber-modified copolymer resins obtained by a vulcanization reaction between a styrene-conjugated diene rubber block copolymer and a conjugated diene rubber.

3. A molded article obtained by injection molding the polycarbonate resin composition according to claim 1 or 2.

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