JP7746140B2 - Polycarbonate resin composition and molded article containing same - Google Patents

Description

The present invention relates to a polycarbonate resin composition and a molded article containing the same.

Polycarbonate resin is a general-purpose engineering plastic, a thermoplastic resin with excellent transparency, impact resistance, heat resistance, and dimensional stability. Due to its excellent properties, it is widely used in fields such as electrical, electronic, IT, machinery, and automotive.

However, polycarbonate resin has the problem of high melt viscosity and poor moldability, and as molded products become thinner and larger, there is a strong demand for improvements in moldability (flowability).

As a means of solving the above problems, many compositions have been proposed in which rubber-modified styrene resins are blended with polycarbonate resin. To improve the moldability of polycarbonate resin, compositions in which acrylonitrile-butadiene-styrene resin (ABS resin) is blended with polycarbonate resin have been used as polymer alloys in many molding fields due to their heat resistance and moldability.

One problem with polymer alloys made by blending ABS resin with polycarbonate resin is that when the blending ratio of ABS resin is increased to improve moldability (fluidity), the ABS resin discolors when exposed to sunlight, including ultraviolet rays, and the overall appearance of the molded product is marred.

The use of hindered amine light stabilizers is a widely known method for improving the light resistance of polymer alloys made from polycarbonate resin and ABS resin. However, hindered amine light stabilizers are basic and are known to decompose the polymer chains of polycarbonate resin, resulting in the problem of reduced impact strength of the product.

Furthermore, adding hindered amine light stabilizers or UV absorbers to polycarbonate resins causes the resin composition to yellow after molding, significantly impairing the appearance of the molded product.

Patent Document 1 proposes a method of adding a polyether polymer to a hindered amine light stabilizer having a specific structure as a method of improving the effect of a hindered amine light stabilizer on polycarbonate resin, but makes no mention of the impact strength of the polycarbonate resin.

Patent Document 2 proposes a method of adding a hindered amine light stabilizer to a resin composition containing a polyester resin and a polycarbonate resin, but makes no mention of the initial yellowness. Furthermore, hindered amine light stabilizers, which have basic properties, accelerate the decomposition of polycarbonate resin, making it difficult to maintain impact strength.

Patent No. 4637980 Patent No. 4880174

The present invention aims to provide a polycarbonate resin composition that maintains the high impact resistance inherent to polycarbonate resin while also providing a good balance of high light resistance and excellent initial appearance, as well as a molded article containing the same.

As a result of intensive research conducted in light of the above-mentioned problems, the inventors discovered that by blending a resin component consisting of a polycarbonate resin and an acrylonitrile-butadiene-styrene resin with an acrylic block copolymer composed of a polymer block containing acrylic ester monomer units and a polymer block containing methacrylic ester monomer units, and a hindered amine light stabilizer, it is possible to maintain high impact strength and achieve a good balance between high light resistance and excellent initial appearance, thereby completing the present invention.

Specifically, the present invention provides a polycarbonate resin composition, characterized by containing, relative to 100 parts by mass of a resin component consisting of 50 to 80 % by mass of polycarbonate resin (A) and 20 to 50% by mass of acrylonitrile-butadiene-styrene resin (B), 0.5 to 10 parts by mass of an acrylic triblock copolymer (C) containing a polymer block (a) containing an acrylic acid ester monomer unit and a polymer block (b) containing a methacrylic acid ester monomer unit , 0.01 to 1.0 part by mass of a hindered amine light stabilizer (D), and 0.1 to 1.0 part by mass of an ultraviolet absorber (E) , and a molded article containing the same.

The present invention provides a polycarbonate resin composition that maintains high impact strength while also exhibiting a good balance of high light resistance and excellent initial appearance, as well as a molded article containing the same.

The polycarbonate composition and molded article of the present invention have high impact strength, high light resistance, and excellent initial appearance. The polycarbonate composition and molded article of the present invention are suitable for electrical equipment, electronic equipment, and IT equipment, and are particularly suitable for meter panel housings and vehicle equipment housings, which are intended for use in environments exposed to sunlight and where the appearance of the molded article is important.

The polycarbonate resin composition of the present invention contains a polycarbonate resin (A), an ABS resin (B), an acrylic triblock copolymer (C), and a hindered amine light stabilizer (D).

The polycarbonate resin (A) used in the present invention is a polymer obtained by the phosgene process, in which various dihydroxydiaryl compounds are reacted with phosgene, or by the transesterification process, in which a dihydroxydiaryl compound is reacted with a carbonate ester such as diphenyl carbonate. A typical example is polycarbonate resin produced from 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A).

The dihydroxydiaryl compounds mentioned above include, in addition to bisphenol A, bis(hydroxyaryl)alkanes such as bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxyphenyl-3-methylphenyl)propane, 1,1-bis(4-hydroxy-3-tert-butylphenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, and 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane; Examples of such hydroxyaryl compounds include bis(hydroxyaryl)cycloalkanes such as 1,1-bis(4-hydroxyphenyl)cyclopentane and 1,1-bis(4-hydroxyphenyl)cyclohexane, dihydroxydiaryl ethers such as 4,4'-dihydroxydiphenyl ether and 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, dihydroxydiaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide, dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide, and dihydroxydiaryl sulfones such as 4,4'-dihydroxydiphenyl sulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone.

These may be used alone or in combination with two or more other compounds, but they may also be used in combination with other compounds such as piperazine, dipiperidylhydroquinone, resorcinol, and 4,4'-dihydroxydiphenyl.

Furthermore, the above dihydroxyaryl compounds may be used in combination with the following trivalent or higher phenolic compounds. Examples of trivalent or higher phenolic compounds include phloroglucin, 4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptene, 2,4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptane, 1,3,5-tri-(4-hydroxyphenyl)-benzene, 1,1,1-tri-(4-hydroxyphenyl)-ethane, and 2,2-bis-[4,4-(4,4'-dihydroxydiphenyl)-cyclohexyl]-propane.

From the perspective of strength, the viscosity average molecular weight of polycarbonate resin (A) is preferably 17,000 to 30,000. Using a polycarbonate resin with such a viscosity average molecular weight results in a polycarbonate resin composition with high impact strength. From the perspectives of molding processability and strength, the viscosity average molecular weight of polycarbonate resin (A) is more preferably 19,000 to 28,000. If the viscosity average molecular weight exceeds 30,000, processability may be impaired. Furthermore, when producing such polycarbonate resin, molecular weight modifiers, catalysts, etc. can be used as needed.

The polymerization method for the acrylonitrile-butadiene-styrene resin (hereinafter also referred to as ABS resin) used in the present invention can be emulsion polymerization, suspension polymerization, bulk polymerization, or other polymerization methods, but ABS resin produced by bulk polymerization (continuous bulk polymerization) is particularly preferred.

The amount of ABS resin (B) blended is preferably 1 to 50 parts by mass per 50 to 99 parts by mass of polycarbonate resin (A). If the amount of ABS resin (B) blended is less than 1 part by mass, moldability may be insufficient, and if the amount of ABS resin (B) blended is more than 50 parts by mass, heat resistance may decrease, which is not preferable.

The acrylic triblock copolymer (C) used in the present invention is composed of a polymer block (a) containing acrylic acid ester monomer units and a polymer block (b) containing methacrylic acid ester monomer units.

The content of the acrylic acid ester monomer units contained in polymer block (a) is preferably 60% by mass or more and 100% by mass or less (i.e., the main component) relative to 100% by mass of polymer block (a), and more preferably 70% by mass or more and 100% by mass or less. Examples of the acrylic acid ester monomer units in polymer block (a) include structural units derived from monomers such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, phenyl acrylate, and dimethylaminoethyl acrylate, and one or more of these may be used.

This polymer block (a) is obtained by a polymerization reaction of the above-mentioned monomers, and the weight-average molecular weight of the polymer block (a) is preferably 6,000 or more and 1,000,000 or less, more preferably 10,000 or more and 800,000 or less, and particularly preferably 15,000 or more and 500,000 or less. Having the weight-average molecular weight of the polymer block (a) within the above range is desirable from the viewpoint of obtaining an acrylic triblock copolymer (C) with excellent impact resistance and fluidity.

In addition to the structural units derived from acrylate esters, polymer block (a) may also contain other structural units, as long as the desired effects are not impaired. Examples of other structural units include other monomers such as glycidyl acrylate, allyl acrylate, acrylonitrile, methacrylonitrile, and olefins.

The content of the methacrylic acid ester monomer units contained in polymer block (b) is preferably 60% by mass or more and 100% by mass or less (i.e., the main component) relative to 100% by mass of polymer block (b), and more preferably 70% by mass or more and 100% by mass or less. Examples of the methacrylic acid ester monomer units in polymer block (b) include structural units derived from monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, n-octyl (meth)acrylate, dodecyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, phenyl (meth)acrylate, and dimethylaminoethyl (meth)acrylate, and one or more of these may be used.

This polymer block (b) is obtained by a polymerization reaction of the above-mentioned monomers, and the weight-average molecular weight of polymer block (b) is preferably 1,000 or more and 1,000,000 or less, more preferably 2,000 or more and 750,000 or less, and particularly preferably 3,000 or more and 500,000 or less. Having a weight-average molecular weight of polymer block (b) within the above range is desirable from the viewpoint of obtaining an acrylic triblock copolymer (C) that has excellent dispersibility in matrix resins.

In addition to the structural units derived from methacrylic acid esters, polymer block (b) may also contain other structural units, as long as the desired effects are not impaired. Examples of other structural units include other monomers such as acrylic acid esters, methacrylic acid, acrylic acid, aromatic vinyl compounds, acrylonitrile, methacrylonitrile, and olefins.

The acrylic triblock copolymer used in the present invention preferably has a triblock structure having a (b)-(a)-(b) structure, in which one end of polymer block (b) is bonded to each of both ends of polymer block (a). By using the triblock structure having the (b)-(a)-(b) structure, it is possible to improve the molding processability of the polycarbonate resin composition while maintaining its high impact strength.

The following methods can be used to produce acrylic triblock copolymers. Specifically, one example is a method of living polymerization of the monomers that make up each block. Examples of such living polymerization techniques include anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of a mineral acid salt, such as an alkali metal or alkaline earth metal salt; anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound; polymerization using an organic rare earth metal complex as a polymerization initiator; and radical polymerization using an α-halogenated ester compound as an initiator in the presence of a copper compound. Other examples include a method in which the monomers that make up each block are polymerized using a polyvalent radical polymerization initiator or a polyvalent radical chain transfer agent to produce a mixture containing the acrylic triblock copolymer of the present invention. Among these methods, anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound is preferred because it produces a block copolymer with high purity and a narrow molecular weight distribution, i.e., it does not contain oligomers that can reduce the impact strength and heat resistance of the polycarbonate resin composition of the present invention, or high molecular weight compounds that can reduce flowability.

From the viewpoint of improving impact resistance, fluidity, and dispersibility, the weight-average molecular weight of the acrylic triblock copolymer (C) in the present invention is preferably 1,000 or more and 1,000,000 or less, and more preferably 2,000 or more and 500,000 or less.

Specific examples of the acrylic triblock copolymer (C) suitable for use in the present invention include a triblock copolymer containing a polymer block having polybutyl acrylate as a monomer unit and a polymer block having polymethyl methacrylate as a monomer unit.

The acrylic triblock copolymer (C) may be used alone or in combination of two or more types. When two or more types are used in combination, block copolymers with different molecular weights or block copolymers with different contents of polymer block (a) containing an acrylic acid ester monomer and polymer block containing monomer units (b) derived from a methacrylic acid ester may be used in combination.

Note that commercially available products may be used as the acrylic triblock copolymer (C), including "LA2149e (product name)" manufactured by Kuraray Co., Ltd., "LA2250 (product name)" manufactured by Kuraray Co., Ltd., "LA4285 (product name)" manufactured by Kuraray Co., Ltd., "LA1114 (product name)" manufactured by Kuraray Co., Ltd., and "LA2140 (product name)" manufactured by Kuraray Co., Ltd.

The blending amount of the acrylic triblock copolymer (C) is preferably 0.5 to 10 parts by mass per 100 parts by mass of the total of the polycarbonate resin (A) and the ABS resin (B). Blending amounts of the acrylic triblock copolymer (C) outside this range are undesirable because they may result in a decrease in impact strength.

The hindered amine light stabilizer (D) used in the present invention can be one represented by the following general formula (1).
General formula (1):
(In general formula (1), R1 and R2 bonded to the nitrogen atom of the piperidine skeleton are each a hydrogen atom or a hydrocarbon substituent which may contain a heteroatom.)

Examples of the hindered amine light stabilizer represented by general formula (1) include N- _CH3 type hindered amine light stabilizers, N-H type hindered amine light stabilizers, and N-R type hindered amine light stabilizers. Here, the N- _CH3 type hindered amine light stabilizer is one in which the hydrogen atom bonded to the nitrogen atom of the piperidine skeleton is substituted with a methyl group, the N-H type hindered amine light stabilizer is one in which the hydrogen atom bonded to the nitrogen atom of the piperidine skeleton is not substituted with an alkyl group (it remains a hydrogen atom), and the N-R type hindered amine light stabilizer is one other than the N-H type hindered amine light stabilizers and N- _CH3 type hindered amine light stabilizers. Of these, the N- _CH3 type hindered amine light stabilizer is preferred.

N- _CH3 type hindered amine light stabilizers are available, for example, as Adeka STAB LA-52, Adeka STAB LA-63P, and Adeka STAB LA-72 manufactured by Adeka Corporation, and as TINUVIN PA144 and TINUVIN 765 manufactured by BASF.

N-R hindered amine light stabilizers are available as Adekastab LA-81 manufactured by Adeka Corporation, Sanol LS2626 manufactured by Sankyo Kasei, and TINUVIN 622 manufactured by BASF.

Specific examples of suitable hindered amine light stabilizers include bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, methyl 1,2,2,6,6-pentamethyl-4-piperidylsebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-N,N'-diformylhexamethylenediamine, dibutylamine-1,3,5-triazine-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, Examples include polycondensation products of N-(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], polymers of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, and copolymers of olefin (C20-24), maleic anhydride, and 4-amino-2,2,6,6-tetramethylpiperidine.

In addition to the above, commercially available products such as ADK STAB LA-77, ADK STAB LA-57, ADK STAB LA-62, ADK STAB LA-67, ADK STAB LA-68, ADK STAB LA-94, ADK STAB LA-82, ADK STAB LA-87, and ADK STAB LA-502XP (all manufactured by ADEKA Corporation) may also be used.

The amount of hindered amine light stabilizer (D) is preferably 0.01 to 1.0 part by mass per 100 parts by mass of the total of polycarbonate resin (A) and ABS resin (B). If the amount of hindered amine light stabilizer (D) is less than 0.01 part by mass, light resistance will be insufficient, which is undesirable. Furthermore, if the amount of hindered amine light stabilizer (D) is more than 1.0 part by mass, the initial appearance may deteriorate (coloration may occur) and impact strength may decrease, which is also undesirable.

The ultraviolet absorber (E) used in the present invention may be a benzotriazole-based ultraviolet absorber, a triazine-based ultraviolet absorber, or the like, with benzotriazole-based ultraviolet absorbers being particularly preferred.

The benzotriazole-based ultraviolet absorber (E) used in the present invention includes 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, 2-(2-hydroxy-3,5-dicumylphenyl)phenylbenzotriazole, 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], 2-(2-hydroxy-3,5-di-tert-butylphenyl)benzotriazole, )benzotriazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-tert-amylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-4-octoxyphenyl)benzotriazole, 2,2'-methylenebis(4-cumyl-6-benzotriazolephenyl), 2,2'-p-phenylenebis(1,3-benzoxazin-4-one), etc.

Of these, 2-(2-hydroxy-5-t-octylphenyl)benzotriazole is particularly suitable, and commercially available products include TINUVIN 329 (TINUVIN is a registered trademark) manufactured by BASF, Seesorb 709 manufactured by Shipro Kasei Co., Ltd., and Chemisorb 79 manufactured by Chemipro Kasei Co., Ltd.

The amount of ultraviolet absorber (E) blended is preferably 0.1 to 1.0 parts by mass per 100 parts by mass of the resin component. A blending amount of less than 0.1 part by mass results in poor weather resistance, while a blending amount of more than 1.0 part by mass is undesirable because it can cause initial discoloration. A more preferred blending amount of ultraviolet absorber (E) is 0.1 to 0.6 parts by mass, and even more preferably 0.1 to 0.4 parts by mass.

Furthermore, the polycarbonate resin composition according to the embodiment may contain, as appropriate, various additives such as antioxidants (e.g., 2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine, Sumilizer GP manufactured by Sumitomo Chemical Co., Ltd. ("Sumilizer" is a registered trademark)), release agents (e.g., fatty acid ester: glycerin monostearate, Rikemal S-100A manufactured by Riken Vitamin Co., Ltd.), heat stabilizers, colorants, softeners, antistatic agents, and impact modifiers, as well as polymers other than the aromatic polycarbonate resin (A), ABS resin (B), and acrylic triblock copolymer (C), provided that the effects of the present invention are not impaired.

The polycarbonate resin composition of the present invention can be produced by mixing polycarbonate resin (A), ABS resin (B), acrylic triblock copolymer (C), and hindered amine light stabilizer (D), and, as necessary, mixing various additives and/or other polymers. As long as the polycarbonate resin composition desired by the present invention can be obtained, the production method is not particularly limited, and the type and amount of each component can be adjusted as appropriate. The method for mixing the components is also not particularly limited, and examples include mixing using a known mixer such as a tumbler or ribbon blender, or melt-kneading using an extruder. Pellets of the polycarbonate resin composition can be easily obtained by these methods.

The molded article according to the present invention can be obtained by molding the above-mentioned polycarbonate resin composition.

As long as the molded article intended by the present invention can be obtained, there are no particular limitations on the method for producing the molded article. Examples include methods of molding a polycarbonate resin composition by known injection molding methods, compression molding methods, etc.

The molded articles of the present invention are suitable for housings for electrical and electronic devices, IT devices, and vehicle meter panels, and are particularly suitable for peripheral vehicle components and housings that require heat resistance.

The above describes an embodiment as an example of the present invention. However, the technology of the present invention is not limited to this and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate.

The present invention will be described in more detail below using examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" and "%" are all by mass.

The following raw materials were used:
1. Polycarbonate resin (A)
Polycarbonate resin 1-1 synthesized from bisphenol A and carbonyl chloride, SD Polyca 200-3 (trade name) (viscosity average molecular weight: 28500) manufactured by Sumika Polycarbonate Co., Ltd.: "SD Polyca" is a registered trademark of Sumika Polycarbonate Co., Ltd., hereinafter abbreviated as "PC-1" 1-2, SD Polyca 200-13 (trade name) (viscosity average molecular weight: 21500) manufactured by Sumika Polycarbonate Co., Ltd.: "SD Polyca" is a registered trademark of Sumika Polycarbonate Co., Ltd., hereinafter abbreviated as "PC-2" 1-3, SD Polyca 200-30 (trade name) (viscosity average molecular weight: 17600) manufactured by Sumika Polycarbonate Co., Ltd.: "SD Polyca" is a registered trademark of Sumika Polycarbonate Co., Ltd., hereinafter abbreviated as "PC-3"

2. ABS resin (B)
2-1. MAGNUM A-156 (product name) manufactured by Trinseo
(Bulk polymerization ABS resin): "MAGNUM" is a registered trademark of Trinseo Co., Ltd., hereinafter abbreviated as "ABS-1" 2-2, Santac AT05 (product name) manufactured by Nippon A&L Co., Ltd.
(Bulk polymerization ABS resin): "Santac" is a registered trademark of Nippon A&L Co., Ltd., hereinafter abbreviated as "ABS-2" 2-3, Clalastic SXH330 (product name) manufactured by Nippon A&L Co., Ltd.
(Emulsion polymerized ABS resin): "Clarastic" is a registered trademark of Nippon A&L Co., Ltd., hereinafter abbreviated as "ABS-3"

3. Acrylic triblock copolymer (C) composed of a polymer block (a) containing an acrylic acid ester monomer unit and a polymer block containing a methacrylic acid ester monomer unit
3-1. Kuraray Clarity LA2140 (product name)
(Low molecular weight acrylic triblock copolymer): "CLARITY" is a registered trademark of Kuraray Co., Ltd., hereinafter abbreviated as "MAM-1" 3-2, Kuraray Clarity LA2330 (product name)
(Medium molecular weight acrylic triblock copolymer): "CLARITY" is a registered trademark of Kuraray Co., Ltd., hereinafter abbreviated as "MAM-2" 3-3, Kuraray Co., Ltd. Clarity LA3320 (product name)
(High molecular weight acrylic triblock copolymer): "CLARITY" is a registered trademark of Kuraray Co., Ltd., hereinafter abbreviated as "MAM-3"

4. Hindered amine light stabilizer (D)
4-1. Adeka Stab LA-52 (product name) manufactured by Adeka Corporation
(Low molecular weight hindered amine): "ADK STAB" is a registered trademark of ADEKA CORPORATION, hereinafter abbreviated as "HALS-1" 4-2. ADK STAB LA-63P (trade name) manufactured by ADEKA CORPORATION
(High molecular weight hindered amine): "ADK STAB" is a registered trademark of ADEKA CORPORATION, hereinafter abbreviated as "HALS-2" 4-3. ADK STAB LA-81 (trade name) manufactured by ADEKA CORPORATION
(Low molecular weight hindered amine): "ADEKA STAB" is a registered trademark of ADEKA CORPORATION, hereinafter abbreviated as "HALS-3" 4-4. Sanol LS-2626 (trade name) manufactured by Sankyo Kasei Co., Ltd.
(High molecular weight hindered amine): "Sanol" is a registered trademark of Sankyo Kasei Co., Ltd., hereinafter abbreviated as "HALS-4"

5. Ultraviolet absorber (E)
5-1. Chemisorb 79 (product name) manufactured by Chemipro
(Low molecular weight benzotriazole type ultraviolet absorber): "Chemisorb" is a registered trademark of Chemipro Kasei Co., Ltd., hereinafter abbreviated as "UVA-1" 5-2. Adeka Stab LA-31RG (trade name) manufactured by Adeka Corporation
(High molecular weight benzotriazole type ultraviolet absorber): "ADEKA STAB" is a registered trademark of ADEKA CORPORATION, hereinafter abbreviated as "UVA-2" 5-3. ADEKA STAB LA-36 (trade name) manufactured by ADEKA CORPORATION
(Low molecular weight benzotriazole type ultraviolet absorber): "ADEKA STAB" is a registered trademark of ADEKA CORPORATION, hereinafter abbreviated as "UVA-3" 5-4. BASF Tinuvin T-1577ED (trade name)
(Triazine-type ultraviolet absorber): "Tinuvin" is a registered trademark of BASF Ltd., hereinafter abbreviated as "UVA-4"

(Examples 1 to 24 and Comparative Examples 1 to 5)
The various ingredients described above were all charged into a tumbler in the blending ratios shown in Tables 1 to 5, dry-mixed for 10 minutes, and then kneaded using a twin-screw extruder (TEX30α manufactured by The Japan Steel Works, Ltd.) at a melt temperature of 240°C to obtain pellets of a resin composition. The resin composition contains 0.2 parts by mass of Sumilizer GP as a phosphorus-based antioxidant and 0.1 parts by mass of S-100A as a mold release agent, per 100 parts by mass of the resin component.

(Evaluation of notched Charpy impact strength)
The pellets of each resin composition obtained above were each dried at 100°C for 4 hours, and then test specimens were prepared in accordance with the ISO test method using an injection molding machine (FANUC ROBOSHOT S2000i100B) at a set temperature of 250°C. Using the test specimens obtained, the notched Charpy impact strength was measured in accordance with ISO 179-1 and ISO 75-2. A notched Charpy impact strength of 90 KJ/m2 or ^more was evaluated as ⊚, 80 KJ/m2 or ^more but less than 90 KJ/ ^m2 as ○, and less than 80 KJ/ ^m2 as ×.

(Evaluation of initial coloration due to additives)
The pellets of each resin composition obtained above were each dried at 100°C for 4 hours, and then flat test pieces measuring 80 mm x 50 mm x 2 mm were prepared using an injection molding machine (ROBOSHOT S2000i100B manufactured by FANUC) at a set temperature of 260°C. Next, the yellowness index (YI(1)) was measured using a spectrophotometer (CMS-35SP manufactured by Murakami Color Research Institute) using a D65 light source, a viewing angle of 10°, and a reflection method.

Furthermore, flat test specimens were similarly prepared for polycarbonate resin compositions that did not contain the hindered amine light stabilizer (D) or the ultraviolet absorber (E), and the yellowness index (YI(2)) was measured in the same manner.

The difference between the measured yellowness index (YI(1)) and the yellowness index (YI(2)) was calculated and used as the initial YI. An initial YI of less than 3.0 was rated as ◎, 3.0 or greater but less than 9.0 as ○, and 9.0 or greater as ×.

(Evaluation of light resistance)
The pellets of each resin composition obtained above were each dried at 100°C for 4 hours, and then flat test pieces measuring 80mm x 50mm x 2mm were prepared using an injection molding machine (ROBOSHOT S2000i100B, manufactured by FANUC) at a set temperature of 250°C. Next, using a highly accelerated weathering tester (Super Xenon Weather Meter SX75, manufactured by Suga Test Instruments Co., Ltd.), the samples were irradiated for 300 hours under conditions of a radiation intensity of 180 W/ ^m2 , a BPT temperature of 63°C, and a chamber humidity of 50% RH. After irradiation, the yellowness index (YI(3)) was measured using a spectrophotometer (CMS-35SP, manufactured by Murakami Color Research Institute) using a D65 light source, a viewing angle of 10°, and a reflection method.

The difference between the measured yellowness index (YI(3)) and the yellowness index (YI(1)) was calculated and this value was designated as ΔYI. ΔYI of less than 40 was designated as ◎, 40 to less than 50 as ○, and 50 or more as ×.

As shown in Tables 1 to 4, when the polycarbonate resin composition satisfied all of the constituent requirements of the present invention (Examples 1 to 24), good results were observed across all evaluation items.

On the other hand, as shown in Table 5, when the polycarbonate resin compositions did not satisfy the constituent requirements of the present invention (Comparative Examples 1 to 5), all of them had some kind of drawback.

In Comparative Examples 1 and 2, a significant decrease in impact strength was observed due to the absence of an acrylic triblock copolymer and the addition of a hindered amine light stabilizer.

In Comparative Example 3, the amount of hindered amine light stabilizer and UV absorber blended was less than the specified amount, and significant yellowing was observed after the accelerated weather resistance test.

In Comparative Example 4, the amount of hindered amine light stabilizer blended was greater than the specified amount, and yellowing of the initial appearance was observed.

In Comparative Example 5, the amount of hindered amine light stabilizer blended was greater than the specified amount, and despite the inclusion of an acrylic triblock copolymer, a significant decrease in impact strength was observed.

The polycarbonate composition of the present invention has a good balance of high impact properties, high light resistance, and excellent initial appearance, making it suitable for housings of electrical equipment, electronic equipment, IT equipment, and vehicle equipment, and is particularly suitable for meter panel housings and vehicle equipment housings that are expected to be used in environments exposed to sunlight and where design is also important.

Claims (7)

A polycarbonate resin composition comprising 100 parts by mass of a resin component consisting of 50 to 80 % by mass of a polycarbonate resin (A) and 20 to 50% by mass of an acrylonitrile-butadiene-styrene resin (B), 0.5 to 10 parts by mass of an acrylic triblock copolymer (C) containing a polymer block (a) containing an acrylic acid ester monomer unit and a polymer block (b) containing a methacrylic acid ester monomer unit, 0.01 to 1.0 part by mass of a hindered amine light stabilizer (D) , and 0.1 to 1.0 part by mass of an ultraviolet absorber (E) . The polycarbonate resin composition according to claim 1, wherein the viscosity average molecular weight of the polycarbonate resin (A) is 17,000 to 30,000. The polycarbonate-based resin composition according to claim 1, wherein the acrylic triblock copolymer (C) is a triblock copolymer in which one end of the polymer block (b) is bonded to each of both ends of the polymer block (a). 2. The polycarbonate resin composition according to claim 1, wherein the hindered amine light stabilizer (D) has a structure represented by the following general formula (1):
General formula (1):
(In general formula (1), R1 and R2 bonded to the nitrogen atom of the piperidine skeleton are each a hydrogen atom or a hydrocarbon substituent which may contain a heteroatom.) The polycarbonate resin composition according to claim 1, characterized in that the ultraviolet absorber (E) has a benzotriazole structure. A molded article comprising the polycarbonate resin composition according to any one of claims 1 to 5 . The molded article according to claim 6 , wherein the molded article comprises a housing for an electronic device or a housing for a vehicle part.