Flame-retardant polycarbonate resin composition and molded article composed of the same

Abstract

To provide a flame-retardant polycarbonate resin composition which is excellent in alkali oil resistance, thinning flame retardancy, impact resistance and surface appearance.SOLUTION: A flame-retardant polycarbonate resin composition contains, with respect to 100 pts.wt. of a component composed of 30 to 50 pts.wt. of (A) a polycarbonate resin (component A) and 70 to 50 pts.wt. of (B) a polybutylene terephthalate resin (component B), 10 to 20 pts.wt. of (C) a brominated polycarbonate-based flame retardant (component C), 1 to 5 pts.wt. of (D) antimony pentaoxide, 1 to 4.5 pts.wt. of (E) a core-shell type graft copolymer obtained by graft polymerization of acrylic rubber as a core component and a (meth)acrylate compound as a shell component, more than 2 pts.wt. and 5 pts.wt. or less of (F) a talc (component F) having an average particle diameter of 0.1 to 10 μm, 0.1 to 1 pts.wt. of (G) a drip prevention agent (component G), and 0.01 to 0.5 pts.wt. of (H) a transesterification reaction prevention agent (component H).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a flame-retardant polycarbonate resin composition having excellent alkali oil resistance, thin-wall flame retardancy, impact resistance and surface appearance, and to a molded article made from the same. [Background technology]

[0002] Polycarbonate resin has excellent mechanical properties, thermal properties, and self-extinguishing properties, making it widely used in machine parts, automotive parts, electrical and electronic components, and office equipment parts. However, polycarbonate resin has the drawback of having a high melt viscosity and poor flowability during injection molding, which can easily generate residual stress during molding. It is also prone to cracking when exposed to alkaline chemicals, making it difficult to use as an exterior material for factory automation (FA) equipment, which often uses highly corrosive alkaline oils. To address these issues, a method has been proposed in which polycarbonate resin is melt-blended with polybutylene terephthalate resin.

[0003] Furthermore, when imparting flame retardancy to a resin composition obtained by melt-blending polycarbonate resin and polybutylene terephthalate resin, a common method is to add a bromine-based flame retardant and an antimony compound. For example, a resin composition comprising polybutylene terephthalate resin, polycarbonate resin, a halogen-based flame retardant, antimony trioxide, and an ester interchange inhibitor has been disclosed (Patent Document 1). However, the resin composition described in Patent Document 1 contains antimony trioxide, which accelerates the ester interchange reaction between the polybutylene terephthalate resin and the polycarbonate resin during melt processing. As a result, molded articles obtained from this composition have insufficient alkali oil resistance and impact resistance, posing practical problems. Furthermore, in recent years, the thickness of exterior materials for factory automation equipment has been reduced, and accordingly, thin-wall flame retardancy is required. For example, a 0.75 mm thick material is required to meet the UL94 standard V-0 flame retardancy standard, which is becoming difficult to achieve with conventional formulations.

[0004] Next, a method of suppressing transesterification reactions by incorporating antimony pentoxide instead of antimony trioxide has been disclosed. For example, a resin composition comprising a polybutylene terephthalate resin, a polycarbonate resin, an impact modifier containing a butadiene component, a brominated flame retardant, antimony pentoxide, and an anti-drip agent (Patent Document 2) and a resin composition comprising a polybutylene terephthalate resin, a polycarbonate resin, an elastomer, a brominated flame retardant, and antimony pentoxide (Patent Document 3) have been disclosed. However, because antimony pentoxide has a lower flame retardant efficiency than antimony trioxide, a large amount of flame retardant must be incorporated to achieve thin-wall flame retardancy. The resin composition of Patent Document 2 contains a large amount of brominated flame retardant, resulting in insufficient alkaline oil resistance and impact resistance. The resin composition described in Patent Document 3 contains a large amount of antimony pentoxide, resulting in insufficient alkaline oil resistance and impact resistance, and the large amount of antimony pentoxide impairs the appearance of the molded product surface. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-314664 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-95033 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-162820 Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the above, an object of the present invention is to provide a flame-retardant polycarbonate resin composition which is excellent in alkali oil resistance, thin-wall flame retardancy, impact resistance and surface appearance, and a molded article made from the same. [Means for solving the problem]

[0007] As a result of intensive research conducted by the present inventors to solve the above problems, they have found that a flame-retardant polycarbonate resin composition having excellent alkali oil resistance, thin-wall flame retardancy, impact resistance, and surface appearance can be obtained by adding to a polycarbonate resin a core-shell graft copolymer having a core component of polybutylene terephthalate resin, a brominated polycarbonate flame retardant, antimony pentoxide, and an acrylic rubber, and a shell component obtained by graft polymerizing a (meth)acrylic acid ester compound, talc having an average particle size of 0.1 to 10 μm, an anti-drip agent, and an transesterification reaction inhibitor. This finding led to the completion of the present invention.

[0008] According to the present invention, the above object is achieved by the following items 1 to 4. 1. A flame-retardant polycarbonate resin composition characterized by containing, relative to 100 parts by weight of components consisting of 30 to 50 parts by weight of (A) polycarbonate resin (component A) and 70 to 50 parts by weight of (B) polybutylene terephthalate resin (component B), 10 to 20 parts by weight of (C) brominated polycarbonate flame retardant (component C), 1 to 5 parts by weight of (D) antimony pentoxide (component D), 1 to 4.5 parts by weight of (E) a core-shell graft copolymer (component E) having an acrylic rubber as the core component and a (meth)acrylic acid ester compound as the shell component by graft polymerization, (F) more than 2 parts by weight and not more than 5 parts by weight of talc (component F) having an average particle size of 0.1 to 10 μm, (G) anti-drip agent (component G), and 0.1 to 1 part by weight of (H) transesterification reaction inhibitor (component H). 2. The flame-retardant polycarbonate resin composition according to item 1 above, wherein component H is at least one compound selected from the group consisting of phosphite compounds and phosphate compounds. 3. A molded article made from the flame-retardant polycarbonate resin composition according to item 1 or 2 above. 4. Molded products as described in the preceding paragraph 3 that are exterior materials for factory automation equipment.

[0009] The present invention will be described in detail below.

[0010] (Component A: Polycarbonate resin) The polycarbonate resin used in the present invention is obtained by reacting a dihydric phenol with a carbonate precursor, and examples of the reaction method include interfacial polymerization, melt transesterification, solid-phase transesterification of carbonate prepolymers, and ring-opening polymerization of cyclic carbonate compounds.

[0011] Representative examples of dihydric phenols used herein include hydroquinone, resorcinol, 4,4'-biphenol, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A), 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 2,2-bis(4-hydroxyphenyl)pentane, 4,4'-(p-phenylene) Examples of suitable dihydric phenols include 4,4'-(m-phenylenediisopropylidene)diphenol, 4,4'-(m-phenylenediisopropylidene)diphenol, 1,1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane, bis(4-hydroxyphenyl)oxide, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)ketone, bis(4-hydroxyphenyl)ester, bis(4-hydroxy-3-methylphenyl)sulfide, 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene. Preferred dihydric phenols are bis(4-hydroxyphenyl)alkanes, and among these, bisphenol A is particularly preferred and widely used in terms of impact resistance.

[0012] In the present invention, in addition to bisphenol A-based polycarbonate resins, which are general-purpose polycarbonate resins, it is also possible to use special polycarbonate resins produced using other dihydric phenols as the A component.

[0013] For example, polycarbonate resins (homopolymers or copolymers) containing 4,4'-(m-phenylenediisopropylidene)diphenol (hereinafter sometimes abbreviated as "BPM"), 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (hereinafter sometimes abbreviated as "Bis-TMC"), 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (hereinafter sometimes abbreviated as "BCF") as part or all of the dihydric phenol components are suitable for applications requiring particularly strict resistance to dimensional change due to water absorption and dimensional stability. These dihydric phenols other than BPA are preferably used in an amount of 5 mol% or more, and particularly 10 mol% or more, of the total dihydric phenol components constituting the polycarbonate resin.

[0014] In particular, when high rigidity and better hydrolysis resistance are required, it is particularly suitable that the component A constituting the resin composition is a copolymer polycarbonate resin of the following (1) to (3). (1) A copolymer polycarbonate resin in which, based on 100 mol% of the dihydric phenol component constituting the polycarbonate resin, BPM accounts for 20 to 80 mol% (more preferably 40 to 75 mol%, and even more preferably 45 to 65 mol%) and BCF accounts for 20 to 80 mol% (more preferably 25 to 60 mol%, and even more preferably 35 to 55 mol%). (2) A copolymer polycarbonate resin in which, based on 100 mol% of the dihydric phenol components constituting the polycarbonate resin, BPA accounts for 10 to 95 mol% (more preferably 50 to 90 mol%, and even more preferably 60 to 85 mol%) and BCF accounts for 5 to 90 mol% (more preferably 10 to 50 mol%, and even more preferably 15 to 40 mol%). (3) A copolymer polycarbonate resin in which, based on 100 mol% of the dihydric phenol component constituting the polycarbonate resin, BPM accounts for 20 to 80 mol% (more preferably 40 to 75 mol%, and even more preferably 45 to 65 mol%) and Bis-TMC accounts for 20 to 80 mol% (more preferably 25 to 60 mol%, and even more preferably 35 to 55 mol%).

[0015] These special polycarbonate resins may be used alone or in a suitable mixture of two or more types, or may be used in a mixture with a commonly used bisphenol A polycarbonate resin.

[0016] The production methods and properties of these special polycarbonate resins are described in detail in, for example, Japanese Patent Application Laid-Open Nos. 6-172508, 8-27370, 2001-55435 and 2002-117580.

[0017] Among the various polycarbonate resins mentioned above, those in which the copolymer composition and the like are adjusted to bring the water absorption rate and Tg (glass transition temperature) into the ranges described below have good hydrolysis resistance of the polymer itself and are remarkably excellent in terms of low warpage after molding, and are therefore particularly suitable in fields where dimensional stability is required. (i) a polycarbonate resin having a water absorption rate of 0.05 to 0.15%, preferably 0.06 to 0.13%, and a Tg of 120 to 180°C; or (ii) A polycarbonate resin having a Tg of 160 to 250°C, preferably 170 to 230°C, and a water absorption of 0.10 to 0.30%, preferably 0.13 to 0.30%, more preferably 0.14 to 0.27%.

[0018] Here, the water absorption rate of polycarbonate resin is a value measured by using a disk-shaped test piece with a diameter of 45 mm and a thickness of 3.0 mm and immersing it in water at 23°C for 24 hours in accordance with ISO 62-1980, and then measuring the moisture content. Also, Tg (glass transition temperature) is a value determined by differential scanning calorimetry (DSC) measurement in accordance with JIS K7121.

[0019] Carbonate precursors that can be used include carbonyl halides, carbonic acid diesters, and haloformates, and specific examples include phosgene, diphenyl carbonate, and dihaloformates of dihydric phenols.

[0020] When producing a polycarbonate resin by interfacial polymerization of the dihydric phenol and carbonate precursor, a catalyst, a terminal terminator, an antioxidant to prevent oxidation of the dihydric phenol, etc. may be used as needed. The polycarbonate resin of the present invention also includes branched polycarbonate resins copolymerized with a trifunctional or higher polyfunctional aromatic compound, polyester carbonate resins copolymerized with an aromatic or aliphatic (including alicyclic) bifunctional carboxylic acid, copolymerized polycarbonate resins copolymerized with a bifunctional alcohol (including alicyclic), and polyester carbonate resins copolymerized with such bifunctional carboxylic acid and bifunctional alcohol. Mixtures of two or more of the resulting polycarbonate resins may also be used.

[0021] The reaction modes of the methods for producing the polycarbonate resin of the present invention, such as interfacial polymerization, melt transesterification, carbonate prepolymer solid-phase transesterification, and ring-opening polymerization of a cyclic carbonate compound, are well known in various literatures and patent publications.

[0022] The viscosity average molecular weight (M) of the polycarbonate resin is not particularly limited, but is preferably 1.8×10 4 ~4.0×10 4 and more preferably 1.9 × 10 4 ~3.5×10 4 , and more preferably 2.0 × 10 4 ~3.0×10 4 The viscosity average molecular weight is 1.8 × 10 4 Polycarbonate resins with a viscosity average molecular weight of less than 4.0 × 10 may not provide good mechanical properties. 4 Resin compositions obtained from polycarbonate resins exceeding this range may be inferior in versatility due to poor flowability during injection molding.

[0023] The viscosity average molecular weight in the present invention is determined by first calculating the specific viscosity (η SP ) was measured using an Ostwald viscometer from a solution of 0.7 g of polycarbonate resin dissolved in 100 ml of methylene chloride at 20°C. Specific viscosity (η SP )=(t-t0) / t0 [t0 is the number of seconds that methylene chloride falls, and t is the number of seconds that the sample solution falls] The calculated specific viscosity (η SP ) and calculate the viscosity average molecular weight M using the following formula: η SP / c=[η]+0.45×[η] 2 c (where [η] is the intrinsic viscosity) [η]=1.23×10 -4 M 0.83 c=0.7

[0024] The viscosity average molecular weight of the polycarbonate resin in the flame-retardant polycarbonate resin composition of the present invention is calculated as follows: The composition is mixed with 20 to 30 times the weight of methylene chloride to dissolve the soluble components in the composition. The soluble components are collected by filtration through Celite. The solvent in the resulting solution is then removed. The solid obtained after solvent removal is thoroughly dried to obtain a solid of components soluble in methylene chloride. 0.7 g of this solid is dissolved in 100 ml of methylene chloride, and the specific viscosity at 20°C is determined in the same manner as above. The viscosity average molecular weight M is then calculated from the specific viscosity in the same manner as above.

[0025] As the polycarbonate resin of the present invention, a polycarbonate-polydiorganosiloxane copolymer resin can also be used.

[0026] Furthermore, polycarbonate resins recycled from used products, i.e., recycled polycarbonate resins, can also be used. Preferred examples of used products include soundproof walls, automobile windows, various glazing materials such as translucent roofing materials and automobile sunroofs, transparent components such as windshields and automobile headlamp lenses, containers such as water bottles, light guide plates, eyeglass lenses, and optical recording media. In addition, crushed products obtained from non-conforming products, sprues, runners, etc., or pellets obtained by melting these can also be used.

[0027] (Component B: Polybutylene terephthalate resin) The resin composition of the present invention contains a polybutylene terephthalate resin as component B. The polybutylene terephthalate resin is obtained by polycondensation of terephthalic acid or its ester-forming derivative with a C4 alkylene glycol or its ester-forming derivative. The polybutylene terephthalate resin may also be a copolymer containing 70% or more by weight of the polybutylene terephthalate resin itself.

[0028] Examples of dibasic acid components other than terephthalic acid and its lower alcohol esters include aliphatic and aromatic polybasic acids such as isophthalic acid, naphthalenedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, and succinic acid, or ester-forming derivatives thereof. Examples of glycol components other than 1,4-butanediol include ordinary alkylene glycols, for example, lower alkylene glycols such as ethylene glycol, diethylene glycol, propylene glycol, trimethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexanedimethanol, and 1,3-octanediol; aromatic alcohols such as bisphenol A and 4,4'-dihydroxybiphenyl; alkylene oxide adduct alcohols such as an ethylene oxide 2-mol adduct of bisphenol A and a propylene oxide 3-mol adduct of bisphenol A; and polyhydroxy compounds such as glycerin and pentaerythritol, or ester-forming derivatives thereof.

[0029] In the present invention, any of the polybutylene terephthalate resins produced by polycondensation of the above-mentioned compounds as monomer components can be used as Component B of the present invention, and they can be used alone or in combination of two or more types.

[0030] The intrinsic viscosity of the polybutylene terephthalate resin used in the present invention is not particularly limited, but is preferably 0.6 to 1.4 dL / g, more preferably 0.7 to 1.35 dL / g, and even more preferably 0.8 to 1.3 dL / g. If the intrinsic viscosity is less than 0.6 dL / g, good mechanical properties may not be obtained. On the other hand, a resin composition obtained from a polybutylene terephthalate resin having an intrinsic viscosity of more than 1.4 dL / g may have poor versatility due to poor fluidity during injection molding. The intrinsic viscosity of the polybutylene terephthalate resin is a value measured at 35°C using o-chlorophenol as a solvent.

[0031] The content of component B is 50 to 70 parts by weight, preferably 52 to 68 parts by weight, and more preferably 54 to 66 parts by weight, per 100 parts by weight of the components consisting of components A and B. If the content of component B is less than 50 parts by weight, the alkali oil resistance deteriorates, and if it exceeds 70 parts by weight, the thin-wall flame retardancy and impact resistance deteriorate.

[0032] (Component C: Brominated polycarbonate flame retardant) The resin composition of the present invention contains a brominated polycarbonate flame retardant as component C. Brominated polycarbonate flame retardants have excellent heat resistance and can significantly improve flame retardancy. The brominated polycarbonate flame retardant used in the present invention is a brominated polycarbonate compound in which structural units represented by the following formula (1) account for preferably at least 60 mol %, more preferably at least 80 mol %, of all structural units, and particularly preferably consists essentially of structural units represented by the following formula (1):

[0033] [ka]

[0034] In formula (1), X is a bromine atom, and R is an alkylene group having 1 to 4 carbon atoms, an alkylidene group having 1 to 4 carbon atoms, or -SO2-. In addition, in the formula (1), R preferably represents a methylene group, an ethylene group, an isopropylidene group, or -SO2-, and particularly preferably represents an isopropylidene group.

[0035] The brominated polycarbonate flame retardant preferably has a small amount of residual chloroformate terminal groups, with the terminal chlorine content being 0.3 ppm or less, more preferably 0.2 ppm or less. The terminal chlorine content can be determined by dissolving a sample in methylene chloride, adding 4-(p-nitrobenzyl)pyridine to react with the terminal chlorine (terminal chloroformate), and measuring the resultant using an ultraviolet-visible spectrophotometer (Hitachi U-3200). When the terminal chlorine content is 0.3 ppm or less, the thermal stability of the flame-retardant polycarbonate resin composition is improved, enabling molding at higher temperatures, which may result in a resin composition with better molding processability.

[0036] Furthermore, the brominated polycarbonate flame retardant preferably has few residual terminal hydroxyl groups. More specifically, the amount of terminal hydroxyl groups is preferably 0.0005 mol or less, more preferably 0.0003 mol or less, per mol of the constituent unit of the brominated polycarbonate flame retardant. The amount of terminal hydroxyl groups can be determined by dissolving a sample in deuterated chloroform and measuring the amount of terminal hydroxyl groups. 1 This can be determined by measuring by H-NMR. When the amount of terminal hydroxyl groups is within this range, the thermal stability of the flame-retardant polycarbonate resin composition may be further improved.

[0037] The specific viscosity of the brominated polycarbonate flame retardant is preferably 0.015 to 0.1, more preferably 0.015 to 0.08. The specific viscosity of the brominated polycarbonate flame retardant is calculated according to the above-mentioned formula for calculating the specific viscosity used when calculating the viscosity average molecular weight of the polycarbonate resin, which is the component A of the present invention.

[0038] The content of component C is 10 to 20 parts by weight, preferably 12 to 18 parts by weight, and more preferably 13 to 17 parts by weight, per 100 parts by weight of the components A and B. If the content of component C is less than 10 parts by weight, sufficient thin-wall flame retardancy cannot be obtained, and if it exceeds 20 parts by weight, alkaline oil resistance and impact resistance deteriorate.

[0039] (Component D: antimony pentoxide) The flame-retardant polycarbonate resin composition of the present invention contains antimony pentoxide as Component D. Antimony pentoxide acts as a flame-retardant aid that enhances flame retardancy through a synergistic effect with Component C, thereby improving the flame retardancy effect.

[0040] Antimony trioxide is generally used as a flame retardant aid, but when antimony trioxide is used as a flame retardant aid in a resin composition containing a polycarbonate resin and a polybutylene terephthalate resin, a transesterification reaction between the polycarbonate resin and the polybutylene terephthalate resin is likely to occur, significantly deteriorating the alkaline oil resistance and impact resistance of the resin composition.On the other hand, when antimony pentoxide is used as a flame retardant aid, the transesterification reaction is suppressed, and the deterioration of the alkaline oil resistance and impact resistance of the resin composition is suppressed.

[0041] Antimony pentoxide may be, for example, a compound represented by xNa2O·Sb2O5·yH2O (x = a rational number between 0 and 1, and y = a rational number between 0 and 4). The particle size of antimony pentoxide is not particularly limited, but is preferably 0.5 to 50 μm. Furthermore, the antimony pentoxide may be surface-treated with an epoxy compound, a silane compound, an isocyanate compound, a titanate compound, or the like, as needed.

[0042] Furthermore, the antimony pentoxide used in the present invention is preferably one that, when dispersed in water, gives a slurry with a pH of 5 to 9, more preferably 6 to 8. Slurries with a pH of less than 5 or more than 9 accelerate decomposition of polycarbonate resin and polybutylene terephthalate resin when melted, increasing the amount of gas generated from the resin and possibly deteriorating alkali oil resistance, thin-wall flame retardancy, impact resistance, and surface appearance.

[0043] The content of component D is 1 to 5 parts by weight, preferably 1.3 to 4 parts by weight, and more preferably 1.6 to 3 parts by weight, per 100 parts by weight of the components A and B. If the content of component D is less than 1 part by weight, sufficient thin-wall flame retardancy cannot be obtained, and if it exceeds 5 parts by weight, the alkali oil resistance, impact resistance, and surface appearance deteriorate.

[0044] (Component E: a core-shell graft copolymer obtained by graft polymerizing an acrylic rubber as the core component and a (meth)acrylic ester compound as the shell component) The flame-retardant polycarbonate resin composition of the present invention contains, as Component E, a core-shell graft copolymer obtained by graft polymerizing an acrylic rubber as a core component and a (meth)acrylic acid ester compound as a shell component. The inclusion of Component E enables the composition to achieve good impact resistance. Note that (meth)acrylic is a collective term for acrylic and methacrylic.

[0045] The acrylic rubber of the core component is a cross-linked acrylic ester elastomer, and examples thereof include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, heptyl acrylate, 2-ethylhexyl acrylate, etc. These monomers may be used alone or in combination of two or more.

[0046] Examples of the (meth)acrylic acid ester compound to be graft-polymerized onto the core component as the shell component include methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, octyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, octyl methacrylate, etc. Among these, it is particularly preferable to contain a methacrylic acid ester such as methyl methacrylate as an essential component.

[0047] Such core-shell graft copolymers are commercially available and easily available, for example, Metablen W-600A manufactured by Mitsubishi Chemical Corporation (a core-shell graft copolymer in which the core is mainly composed of butyl acrylate and the shell is graft-copolymerized with methyl methacrylate) and Paraloid EXL-2390 manufactured by Dow Chemical Co., Ltd. (a core-shell graft copolymer in which the core is mainly composed of butyl acrylate and 2-ethylhexyl acrylate and the shell is graft-copolymerized with methyl methacrylate).

[0048] The content of component E is 1 to 4.5 parts by weight, preferably 1.5 to 4.2 parts by weight, and more preferably 2 to 4 parts by weight, per 100 parts by weight of the components A and B. If the content of component E is less than 1 part by weight, sufficient impact resistance cannot be obtained, and if it exceeds 4.5 parts by weight, the alkali oil resistance, thin-wall flame retardancy, and surface appearance deteriorate.

[0049] (Component F: talc with an average particle size of 0.1 to 10 μm) The flame-retardant polycarbonate resin composition of the present invention contains, as component F, talc having an average particle size of 0.1 to 10 μm.

[0050] Talc, as used herein, is hydrous magnesium silicate, generally represented by the chemical formula 4SiO-2-·3MgO·2H2O. It is typically a scaly particle with a layered structure and is composed of 56-65% SiO2 by weight, 8-35% MgO2 by weight, and approximately 5% HO by weight. Other minor components include 0.03-1.2% Fe2O3, 0.05-1.5% Al2O3, 0.05-1.2% CaO, 0.2% or less K2O, and 0.2% or less Na2O. A more preferred talc composition is 62-63.5% SiO2 by weight, 31-32.5% MgO by weight, 0.03-0.15% Fe2O3, 0.05-0.25% Al2O3, and 0.05-0.25% CaO by weight. Furthermore, the ignition loss is preferably 2 to 5.5% by weight. With such a suitable composition, a resin composition having good thermal stability and color can be obtained, and good molded articles can be produced even at higher molding temperatures. This allows the composition of the present invention to have even higher fluidity, which may enable it to be used for larger or more complex-shaped thin-walled molded articles.

[0051] The particle size of the F component is an average particle size of 0.1 to 10 μm, preferably 0.3 to 7 μm, and more preferably 0.5 to 4 μm. If the average particle size of the F component exceeds 10 μm, the thin-wall flame retardancy, impact resistance, and surface appearance deteriorate. It is difficult to industrially produce talc with an average particle size of less than 0.1 μm. The average particle size of talc is D50 (median diameter of particle size distribution) measured by X-ray transmission, which is one of the liquid-phase sedimentation methods. A specific example of an apparatus for performing such measurements is the Sedigraph 5100 manufactured by Micromeritics.

[0052] There are no particular limitations on the method for pulverizing talc from raw ore, and methods such as axial flow milling, annular milling, roll milling, ball milling, jet milling, and container rotation compression shear milling can be used. Furthermore, the talc after pulverization is preferably classified using various classifiers to achieve a uniform particle size distribution. There are no particular limitations on the classifier, and examples include impactor-type inertial force classifiers (such as variable impactors), Coanda effect-based inertial force classifiers (such as elbow jets), and centrifugal field classifiers (such as multi-stage cyclones, microplexes, dispersion separators, AccuCut, turboclassifiers, turboplexes, micron separators, and super separators).

[0053] Furthermore, talc is preferably in an agglomerated state from the viewpoint of ease of handling, etc., and methods for producing such talc include a method using degassing compression, a method using a sizing agent for compression, etc. The method using degassing compression is particularly preferred because it is simple and does not allow unnecessary sizing agent resin components to be mixed into the resin composition of the present invention.

[0054] The content of component F is more than 2 parts by weight and not more than 5 parts by weight, preferably 2.2 to 4.5 parts by weight, and more preferably 2.4 to 4 parts by weight, per 100 parts by weight of the components consisting of components A and B. If the content of component E is 2 parts by weight or less, sufficient thin-wall flame retardancy cannot be obtained, and if it exceeds 5 parts by weight, impact resistance and surface appearance deteriorate.

[0055] (Component G: Anti-drip agent) The flame-retardant polycarbonate resin composition of the present invention contains an anti-drip agent as component G. By including this anti-drip agent, good flame retardancy can be achieved without impairing the physical properties of the molded article.

[0056] Examples of the anti-drip agent include fluorine-containing polymers capable of forming fibrils, such as polytetrafluoroethylene, tetrafluoroethylene copolymers (e.g., tetrafluoroethylene / hexafluoropropylene copolymers), partially fluorinated polymers such as those disclosed in U.S. Patent No. 4,379,910, and polycarbonate resins produced from fluorinated diphenols. Of these, polytetrafluoroethylene (hereinafter sometimes referred to as PTFE) is preferred.

[0057] In addition, in the present invention, coated branched PTFE can be used as an anti-drip agent. The coated branched PTFE is a polytetrafluoroethylene-based mixture consisting of branched polytetrafluoroethylene particles and an organic polymer, and has a coating layer made of an organic polymer, preferably a polymer containing units derived from a styrene-based monomer and / or units derived from an acrylic monomer, on the outside of the branched polytetrafluoroethylene. The coating layer is formed on the surface of the branched polytetrafluoroethylene. Furthermore, the coating layer preferably contains a copolymer of a styrene-based monomer and an acrylic monomer.

[0058] The content of component G is 0.1 to 1 part by weight, preferably 0.2 to 0.8 parts by weight, and more preferably 0.3 to 0.6 parts by weight, per 100 parts by weight of the components A and B. If the content of component G is less than 0.1 part by weight, sufficient thin-wall flame retardancy cannot be obtained, and if it exceeds 1 part by weight, impact resistance and surface appearance deteriorate.

[0059] (Component H: Transesterification inhibitor) The flame-retardant polycarbonate resin composition of the present invention contains a transesterification reaction inhibitor as component H. The transesterification reaction inhibitor can be any compound that deactivates the transesterification reaction catalyst, with phosphite compounds, phosphate compounds, phosphonous acid compounds, phosphonic acid compounds, and their esters, as well as tertiary phosphines, being preferred. Among these, phosphate compounds and phosphite compounds are more preferred because they deactivate the transesterification reaction catalyst quickly, with phosphate compounds being particularly preferred.

[0060] Examples of the phosphate compound include tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triphenyl phosphate, trichlorophenyl phosphate, triethyl phosphate, diphenyl cresyl phosphate, diphenyl monoorthoxenyl phosphate, tributoxyethyl phosphate, dibutyl phosphate, dioctyl phosphate, diisopropyl phosphate, stearyl acid phosphate, octadecyl phosphate, and stearyl acid phosphate metal salts.

[0061] Examples of the phosphite compound include trialkyl phosphites such as tridecyl phosphite, dialkyl monoaryl phosphites such as didecyl monophenyl phosphite, monoalkyl diaryl phosphites such as monobutyl diphenyl phosphite, triaryl phosphites such as triphenyl phosphite and tris(2,4-di-tert-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol, and the like. Examples include pentaerythritol phosphites such as bis(2,4-dicumylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, and cyclic phosphites such as 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite and 2,2′-methylenebis(4,6-di-tert-butylphenyl)(2,4-di-tert-butylphenyl)phosphite.

[0062] The above transesterification reaction inhibitors can be used alone or in combination of two or more.

[0063] The content of component H is 0.01 to 0.5 parts by weight, preferably 0.02 to 0.4 parts by weight, and more preferably 0.03 to 0.3 parts by weight, per 100 parts by weight of the components A and B. If the content is less than 0.01 part by weight, the transesterification reaction is accelerated, resulting in a deterioration in alkali oil resistance, thin-wall flame retardancy, and impact resistance. On the other hand, if the content exceeds 0.5 part by weight, the thin-wall flame retardancy and impact resistance are deteriorated.

[0064] (Other additives) (i) Phenolic stabilizers The resin composition of the present invention may contain a phenolic stabilizer. Examples of phenolic stabilizers include hindered phenols, semi-hindered phenols, and less hindered phenol compounds, but hindered phenol compounds are particularly preferred from the viewpoint of providing heat stability to the polycarbonate resin.

[0065] (ii) UV absorber The flame-retardant polycarbonate resin composition of the present invention may contain an ultraviolet absorber. Examples of ultraviolet absorbers include benzophenone-based, benzotriazole-based, hydroxyphenyltriazine-based, and cyclic iminoester-based compounds. Furthermore, the ultraviolet absorber may be a polymeric ultraviolet absorber obtained by copolymerizing such an ultraviolet-absorbing monomer and / or a photostable monomer with a monomer such as an alkyl (meth)acrylate, by adopting a radically polymerizable monomer compound structure. Suitable examples of the ultraviolet-absorbing monomer include compounds containing a benzotriazole skeleton, a benzophenone skeleton, a triazine skeleton, a cyclic iminoester skeleton, and a cyanoacrylate skeleton in the ester substituent of a (meth)acrylic acid ester. The ultraviolet absorbers may be used alone or in combination of two or more.

[0066] (iii) Hindered amine light stabilizers The flame-retardant polycarbonate resin composition of the present invention may contain a hindered amine light stabilizer. Hindered amine light stabilizers are commonly called HALS (hindered amine light stabilizers) and are compounds having a 2,2,6,6-tetramethylpiperidine skeleton in their structure. Hindered amine light stabilizers are broadly classified into three types based on the bonding partner of the nitrogen atom in the piperidine skeleton: NH type (hydrogen bonded to the nitrogen atom), NR type (an alkyl group (R) bonded to the nitrogen atom), and N-OR type (an alkoxy group (OR) bonded to the nitrogen atom). When applied to polycarbonate resins, the low-basicity NR type or N-OR type is more preferred in terms of the basicity of the hindered amine light stabilizer. Hindered amine light stabilizers can be used alone or in combination of two or more types.

[0067] (iv) Mold release agent The flame-retardant polycarbonate resin composition of the present invention preferably further contains a release agent for the purposes of improving productivity during molding and reducing distortion of molded articles. Known release agents can be used. Examples include saturated fatty acid esters, unsaturated fatty acid esters, polyolefin waxes (polyethylene waxes, 1-alkene polymers, and the like, modified with functional group-containing compounds such as acid-modified waxes), silicone compounds, fluorine compounds (fluorine oils such as polyfluoroalkyl ethers), paraffin wax, and beeswax. Fatty acid esters and polyolefin waxes are particularly preferred release agents.

[0068] (v) Dyes and pigments The flame-retardant polycarbonate resin composition of the present invention can further contain various dyes and pigments, allowing for the provision of molded articles with a wide variety of designs. By blending in a fluorescent brightening agent or other fluorescent dye that emits light, it is possible to impart even better design effects by taking advantage of the emitted color. It is also possible to provide a flame-retardant polycarbonate resin composition that is colored with extremely small amounts of dyes and pigments and has vivid color development.

[0069] (vi) Filling material The flame-retardant polycarbonate resin composition of the present invention can contain various fillers as reinforcing fillers within the range that allows the effects of the present invention to be achieved. Examples include silicate minerals other than talc, calcium carbonate, glass fiber, glass beads, glass balloons, milled glass fiber, glass flakes, carbon fiber, carbon flakes, carbon beads, milled carbon fiber, graphite, vapor-grown ultrafine carbon fibers (fiber diameter less than 0.1 μm), carbon nanotubes (fiber diameter less than 0.1 μm, hollow), fullerenes, metal flakes, metal fibers, metal-coated glass fiber, metal-coated carbon fiber, metal-coated glass flakes, silica, metal oxide particles, metal oxide fibers, metal oxide balloons, and various whiskers (potassium titanate whiskers, aluminum borate whiskers, basic magnesium sulfate, etc.). These reinforcing fillers may be used alone or in combination of two or more.

[0070] (vii) Other additives In addition, small amounts of known additives can be blended into the flame-retardant polycarbonate resin composition of the present invention to impart various functions to molded articles or improve their properties. These additives can be blended in conventional amounts as long as they do not impair the objectives of the present invention. Such additives include sliding agents (e.g., PTFE particles), light diffusing agents (e.g., acrylic crosslinked particles, silicone crosslinked particles, ultrathin glass flakes, calcium carbonate particles), antistatic agents, crystal nucleating agents, inorganic and organic antibacterial agents, photocatalytic antifouling agents (e.g., fine particle titanium oxide, fine particle zinc oxide), radical generators, infrared absorbers (heat ray absorbers), and photochromic agents.

[0071] (Production of Resin Composition) Any method can be used to produce the resin composition of the present invention. For example, components A through H and optional other additives can be thoroughly mixed using a premixing device such as a V-type blender, Henschel mixer, mechanochemical device, or extrusion mixer. The premix can then be granulated, if necessary, using an extrusion granulator or briquetting machine. The premix can then be melt-kneaded in a melt mixer, typically a vented twin-screw extruder, and subsequently pelletized using a pelletizer. Other methods include feeding each component independently to a melt mixer, typically a vented twin-screw extruder, or premixing a portion of each component and then feeding the remaining components separately to the melt mixer. An extruder equipped with a vent capable of removing moisture from the raw materials and volatile gases generated from the melt-kneaded resin is preferably used. A vacuum pump is preferably installed in the vent to efficiently vent the generated moisture and volatile gases to the outside of the extruder. It is also possible to install a screen in a zone before the die of the extruder to remove foreign matter mixed in the raw materials for extrusion, thereby removing the foreign matter from the resin composition. Examples of such a screen include wire mesh, a screen changer, and a sintered metal plate (such as a disc filter). Examples of melt kneaders include a twin-screw extruder, a Banbury mixer, a kneading roll, a single-screw extruder, and a multi-screw extruder with three or more screws.

[0072] The extruded resin as described above is either directly cut and pelletized, or formed into strands, which are then cut and pelletized using a pelletizer. If it is necessary to reduce the influence of external dust during pelletization, it is preferable to purify the atmosphere around the extruder. Furthermore, in the production of such pellets, various methods already proposed for polycarbonate resins for optical disks can be used to narrow the pellet shape distribution, reduce miscuts, reduce fine powder generated during shipping and handling, and reduce bubbles (vacuum bubbles) generated inside the strands or pellets. These methods can achieve high molding cycle times and reduce the incidence of defects such as silver spots. The pellets can be shaped in a variety of common shapes, including cylindrical, prismatic, and spherical, with cylindrical shapes being preferred. The diameter of the cylinder is preferably 1 to 5 mm, more preferably 1.5 to 4 mm, and even more preferably 2 to 3.3 mm. The length of the cylinder is preferably 1 to 30 mm, more preferably 2 to 5 mm, and even more preferably 2.5 to 3.5 mm.

[0073] (Molded article made from the resin composition of the present invention) The resin composition of the present invention can be injection-molded to produce various products from pellets obtained by the above-described method. Injection molding can be performed using not only conventional molding methods but also injection compression molding, injection press molding, gas-assisted injection molding, foam molding (including supercritical fluid injection molding), insert molding, in-mold coating molding, adiabatic mold molding, rapid heating and cooling mold molding, two-color molding, sandwich molding, and ultra-high-speed injection molding, depending on the purpose. The advantages of these molding methods are widely known. Molding can be performed using either a cold runner or hot runner method. The resin composition of the present invention can also be used in the form of various profile extrusion molded products, sheets, films, etc., by extrusion molding. Sheets and films can also be molded using inflation, calendaring, casting, and other methods. Furthermore, heat-shrinkable tubing can be formed by specific stretching procedures. The resin composition of the present invention can also be molded into molded products by rotational molding, blow molding, and other methods. [Effects of the Invention]

[0074] The flame-retardant polycarbonate resin composition of the present invention has excellent alkali oil resistance, thin-wall flame retardancy, impact resistance, and surface appearance, and is therefore useful not only for factory automation equipment exterior materials but also for a wide range of applications including medical equipment, housing equipment, building materials, daily necessities, infrastructure equipment, automobiles, office automation and energy saving applications, outdoor equipment, and various other fields. Therefore, the industrial effects of the present invention are extremely significant. DETAILED DESCRIPTION OF THE INVENTION [Example]

[0075] The embodiments for carrying out the present invention are a summary of the preferred ranges of each of the above-mentioned requirements, and representative examples are described in the following examples. Of course, the present invention is not limited to these embodiments. Evaluations were carried out by the following methods.

[0076] (i) Resistance to alkaline oil Using ISO tensile test specimens obtained by the method described below, a 1% strain was applied using a three-point bending test method, and then a cloth impregnated with alkaline oil (Super Tech DOT3 Brake Fluid (product name) manufactured by Tecnical Chemical Co.) with a pH of 9 was placed over the specimen, and the specimen was left in an environment of 23°C for 240 hours, after which the tensile strength was measured. The tensile strength before the above treatment was also measured, and the tensile strength retention rate after the alkaline oil resistance test was calculated according to the following formula. Tensile strength retention rate (%) = 100 × (tensile strength of test piece after alkaline oil resistance test) / (tensile strength of test piece before alkaline oil resistance test) The tensile strength referred to here refers to the higher of the tensile breaking strength and the tensile yield strength.

[0077] (ii) Thin-walled flame retardant Using UL test specimens (0.75 mm thick) obtained using the method described below, V tests were carried out in accordance with UL 94. The flame retardancy levels decrease in the order of V-0 > V-1 > V-2 > out of standard.

[0078] (iii) Impact resistance Using an ISO bending test piece having a thickness of 4 mm obtained by the method described below, the notched Charpy impact strength was measured in an atmosphere of 23°C in accordance with ISO179.

[0079] (iv) Surface appearance The glossiness of the surface of a sample plate (a three-level plate with holes) prepared by the method described below was evaluated according to the following criteria. ○: When a light from a fluorescent lamp is reflected on the surface of the molded product, it can be distinguished as a fluorescent lamp. ×: When a light from a turned-on fluorescent lamp is reflected on the surface of the molded article, distortion is observed to the extent that it cannot be distinguished from the light from a fluorescent lamp.

[0080] [Examples 1 to 18, Comparative Examples 1 to 15] The mixture with the composition shown in Tables 1 and 2 was fed into the first feed port of the extruder. The feed rate of the mixture was precisely measured using a scale [CWF, manufactured by Kubota Corporation]. The extrusion was carried out using a 30 mm diameter vented twin-screw extruder (TEX30α-38.5BW-3V, manufactured by The Japan Steel Works, Ltd.) at a screw rotation speed of 230 rpm, a discharge rate of 25 kg / h, and a vent vacuum of 3 kPa to obtain pellets by melt mixing. The extrusion temperature from the first feed port to the die was 260°C. A portion of the obtained pellets was dried in a hot air circulation dryer at 100-110°C for 6 hours, and then an injection molding machine was used to prepare ISO tensile test specimens (compliant with ISO527-1 and ISO527-2), ISO flexural test specimens (compliant with ISO178, ISO179, ISO75-1 and ISO75-2), UL test specimens (13 mm wide x 125 mm long x 0.75 mm thick), and sample plates (three-hole plate) at a cylinder temperature of 260°C and a mold temperature of 80°C.

[0081] The symbols used for each component in Tables 1 and 2 are as follows: (Component A) A-1: Aromatic polycarbonate resin (polycarbonate resin powder with a viscosity-average molecular weight of 20,900, made by a conventional method from bisphenol A and phosgene, manufactured by Teijin Limited, product name: Panlite L-1225WS)

[0082] (B component) B-1: Polybutylene terephthalate resin (intrinsic viscosity: 0.965 dl / g, Chang Chun Plastics Co., Ltd., product name: 1100-211MD)

[0083] (C component) C-1: Brominated polycarbonate flame retardant (brominated carbonate oligomer with bisphenol A skeleton, bromine content: 58.0%, Teijin Limited, FG-8500 (product name))

[0084] (D component) D-1: Antimony pentoxide (product name: BurnEx 6220, manufactured by Nyacol Nano Technologies, Ink.)

[0085] (E component) E-1: A core-shell graft copolymer in which the core is primarily composed of butyl acrylate and 2-ethylhexyl acrylate, and the shell is graft-copolymerized with methyl methacrylate (DOW Chemical Co., Ltd., Paraloid EXL-2390 (product name)).

[0086] (F component) F-1: Talc with an average particle size of 2 μm (product name: Victorilite TK-RC, manufactured by Shokoyama Mining Co., Ltd.) F-2: Talc with an average particle size of 0.5 μm (HTP ultra5c (product name) manufactured by IMI Fabi SpA) F-3: Talc with an average particle size of 3.5 μm (Hayashi Kasei Co., Ltd., product name HST0.8) F-4 (Comparative Example): Talc with an average particle size of 15 μm (Victorite SGA (product name) manufactured by Shokoyama Mining Co., Ltd.)

[0087] (G component) G-1: Anti-drip agent (polytetrafluoroethylene, Polyflon MPA FA500H (product name) manufactured by Daikin Industries, Ltd.)

[0088] (H component) H-1: Transesterification inhibitor (octadecyl phosphate, ADEKA Corporation, product name: ADK STAB AX-71) H-2: Transesterification inhibitor (bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, SONGNIOX 6260 PW (product name) manufactured by Songwon Industrial, Co. Ltd.)

[0089] [Table 1]

[0090] [Table 2]

Claims

1. A flame-retardant polycarbonate resin composition comprising 100 parts by weight of a component consisting of 30 to 50 parts by weight of (A) polycarbonate resin (component A) and 70 to 50 parts by weight of (B) polybutylene terephthalate resin (component B), containing 10 to 20 parts by weight of (C) a brominated polycarbonate flame retardant (component C), 1 to 5 parts by weight of (D) antimony pentoxide (component D), 1 to 4.5 parts by weight of (E) a core-shell graft copolymer (component E) having an acrylic rubber as the core component and a (meth)acrylic acid ester compound as the shell component, graft polymerized thereto, (F) more than 2 parts by weight but not more than 5 parts by weight of talc (component F) having an average particle size of 0.1 to 10 μm, 0.1 to 1 part by weight of (G) an anti-drip agent (component G), and 0.01 to 0.5 parts by weight of (H) a transesterification reaction inhibitor (component H).

2. 2. The flame-retardant polycarbonate resin composition according to claim 1, wherein component H is at least one compound selected from the group consisting of phosphite compounds and phosphate compounds.

3. A molded article made from the flame-retardant polycarbonate resin composition according to claim 1 or 2.

4. The molded article according to claim 3, which is an exterior material for factory automation equipment.

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