JP2024049858A - Polycarbonate resin composition - Google Patents

Abstract

To provide a polycarbonate resin composition which has high weather resistance and excellent impact resistance, heat resistance and flowability (moldability).SOLUTION: A polycarbonate resin composition contains, with respect to 100 pts.mass of the total of (A) and (B) of 55 to 90 mass% of a polycarbonate resin (A) having a viscosity average molecular weight of 17,500 to 30,000, and 10 to 45 mass% of a graft copolymer (B) containing an aromatic vinyl monomer component (b1), a vinyl cyanide monomer component (b2) and a diene-based rubbery polymer component (b3), 0.001 to 0.3 pts.mass of triaryl phosphate (C) represented by specific formula (1), and 0 to 0.3 pts.mass of triaryl phosphate (D), wherein a mass ratio (D)/(C) of (D) to (C) is 0 or more and 4 or less.SELECTED DRAWING: None

Description

The present invention relates to a polycarbonate resin composition, and more specifically, to a polycarbonate resin composition having excellent weather resistance and a molded article thereof.

Polycarbonate resins have excellent mechanical properties such as impact resistance, as well as excellent heat resistance, transparency, etc., and are therefore widely used in many applications, such as various optical components, electrical and electronic equipment components, automotive interior and exterior components, office automation equipment components, sheets, machine components, and building materials.
However, polycarbonate resins do not have sufficient weather resistance, and for example, when used outdoors or indoors under fluorescent light, discoloration or loss of strength of the product is observed, so that their use is somewhat limited.

For this reason, various light stabilizers have been used either alone or in combination, and it is known to incorporate ultraviolet absorbents such as benzotriazole-based ones. However, when such ultraviolet absorbents are incorporated into polycarbonate resins, there is a problem that the color of the polycarbonate resin composition is deteriorated due to thermal degradation during melt kneading and molding.
Various additives have also been incorporated to enhance functionality. For example, Patent Document 1 describes that a fiber-reinforced polycarbonate resin composition excellent in dimensional stability, mechanical strength, and fluidity can be obtained by mixing 5 to 15 mass% of triphenyl phosphate with 85 to 95 mass% of polycarbonate resin.

In recent years, as various devices have rapidly become more functional and high-performance, there is a strong demand for polycarbonate resins, particularly for their improved weather resistance.

Japanese Patent No. 3308657

The objective (objective) of the present invention is to provide a polycarbonate resin composition that has excellent weather resistance, good impact resistance, heat resistance, and fluidity (moldability).

Means for Solving the Problems The present inventors have conducted intensive research to achieve the above object, and as a result have found that a polycarbonate resin composition containing a small amount of a specific triaryl phosphate compound and further containing a specific quantitative ratio of triaryl phosphite in a resin alloy with a graft polymer such as ABS resin has excellent weather resistance while having good impact resistance and heat resistance, and have thus completed the present invention.
The present invention relates to the following polycarbonate resin composition and molded article.

［式（１）中、Ｒ^１～Ｒ^５は、それぞれ独立に、水素原子、炭素数１～１２のアルキル基である。］
２．式（１）において、各芳香環上のＲ^１～Ｒ^５は、その少なくとも１つ以上が炭素数１～１２のアルキル基である上記１に記載のポリカーボネート樹脂組成物。
３．式（１）において、各芳香環上のＲ^１、Ｒ^３が炭素数１～１２のアルキル基であり、各芳香環上のＲ^２、Ｒ^４及びＲ^５が水素原子である上記１に記載のポリカーボネート樹脂組成物。
４．式（１）において、各芳香環上のＲ^１、Ｒ^３がｔｅｒｔ－ブチル基であり、各芳香環上のＲ^２、Ｒ^４及びＲ^５が水素原子である上記３に記載のポリカーボネート樹脂組成物。
５．トリアリールホスフェート（Ｃ）が、トリフェニルホスフェート、トリス（２，４ジ－ｔ－ブチルフェニル）ホスフェート、トリス（４－ｔ－ブチルフェニル）ホスフェートのうちの少なくとも１つを含有する上記１に記載のポリカーボネート樹脂組成物。
６．トリアリールホスファイト（Ｄ）を、前記（Ａ）及び（Ｂ）の合計１００質量部に対し、０質量部超０．３質量部以下を含有する上記１記載のポリカーボネート樹脂組成物。
７．トリアリールホスフェート（Ｃ）とトリアリールホスファイト（Ｄ）の含有量の質量比（Ｄ）／（Ｃ）が、０超４以下である上記１に記載のポリカーボネート樹脂組成物。
８．上記１～７のいずれかに記載のポリカーボネート樹脂組成物のペレット。
９．上記１～７のいずれかに記載のポリカーボネート樹脂組成物からなる成形体。
１０．上記８に記載のポリカーボネート樹脂組成物のペレットからなる成形体。 1. A method for producing a polycarbonate resin composition comprising: 55 to 90 mass% of a polycarbonate resin (A) having a viscosity average molecular weight of 17,500 to 30,000; and 10 to 45 mass% of a graft copolymer (B) containing an aromatic vinyl monomer component (b1), a vinyl cyanide monomer component (b2), and a diene rubber polymer component (b3), for a total of 100 mass parts of (A) and (B),
A polycarbonate resin composition comprising 0.001 to 0.3 parts by mass of a triaryl phosphate (C) represented by the following general formula (1), and 0 to 0.3 parts by mass of a triaryl phosphite (D), and the mass ratio (D)/(C) of the contents of the triaryl phosphite (D) to the triaryl phosphate (C) is 0 or more and 4 or less:

[In formula (1), R ¹ to R ⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.]
2. The polycarbonate resin composition according to 1 above, wherein in formula (1), at least one of R ¹ to R ⁵ on each aromatic ring is an alkyl group having 1 to 12 carbon atoms.
3. The polycarbonate resin composition according to 1 above, wherein in formula (1), R ¹ and R ³ on each aromatic ring are an alkyl group having 1 to 12 carbon atoms, and R ² , R ⁴ and R ⁵ on each aromatic ring are hydrogen atoms.
4. The polycarbonate resin composition according to the above 3, wherein in formula (1), R ¹ and R ³ on each aromatic ring are tert-butyl groups, and R ² , R ⁴ and R ⁵ on each aromatic ring are hydrogen atoms.
5. The polycarbonate resin composition according to the above 1, wherein the triaryl phosphate (C) contains at least one of triphenyl phosphate, tris(2,4-di-t-butylphenyl) phosphate, and tris(4-t-butylphenyl) phosphate.
6. The polycarbonate resin composition according to the above item 1, further comprising a triaryl phosphite (D) in an amount of more than 0 part by mass and not more than 0.3 parts by mass per 100 parts by mass of the total of (A) and (B).
7. The polycarbonate resin composition according to the above item 1, wherein the mass ratio (D)/(C) of the contents of the triaryl phosphate (C) and the triaryl phosphite (D) is greater than 0 and equal to or less than 4.
8. Pellets of the polycarbonate resin composition according to any one of 1 to 7 above.
9. A molded article made of the polycarbonate resin composition according to any one of 1 to 7 above.
10. A molded article comprising pellets of the polycarbonate resin composition according to 8 above.

The polycarbonate resin composition of the present invention has high weather resistance and is excellent in impact resistance, heat resistance, and fluidity (moldability).

Hereinafter, the present invention will be described in detail with reference to embodiments and examples.
In this specification, unless otherwise specified, the range "to" is used to mean that the numerical values before and after it are included as the lower limit and upper limit.

The polycarbonate resin composition of the present invention is characterized in that it contains 0.001 to 0.3 parts by mass of triaryl phosphate (C) represented by the general formula (1) and 0 to 0.3 parts by mass of triaryl phosphite (D) relative to a total of 100 parts by mass of (A) and (B) containing 55 to 90% by mass of polycarbonate resin (A) having a viscosity average molecular weight of 17,500 to 30,000 and 10 to 45% by mass of graft copolymer (B) containing aromatic vinyl monomer component (b1), vinyl cyanide monomer component (b2) and diene rubber polymer component (b3), and the mass ratio (D)/(C) of the content of triaryl phosphite (D) to triaryl phosphate (C) is 0 to 4.

[Polycarbonate resin (A)]
The polycarbonate resin (A) used in the present invention is not particularly limited, and various types can be used. Polycarbonate resins can be classified into aromatic polycarbonate resins in which the carbons directly bonded to the carbonate bonds are aromatic carbons, and aliphatic polycarbonate resins in which the carbons directly bonded to the carbonate bonds are aliphatic carbons, and either type can be used. Among them, aromatic polycarbonate resins are preferred as the polycarbonate resin (A) from the viewpoints of heat resistance, mechanical properties, electrical properties, etc.

Among the monomers that are raw materials for aromatic polycarbonate resins, examples of aromatic dihydroxy compounds include:
Dihydroxybenzenes such as 1,2-dihydroxybenzene, 1,3-dihydroxybenzene (i.e., resorcinol), and 1,4-dihydroxybenzene;
Dihydroxybiphenyls such as 2,5-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl, and 4,4'-dihydroxybiphenyl;

Dihydroxynaphthalenes such as 2,2'-dihydroxy-1,1'-binaphthyl, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, and 2,7-dihydroxynaphthalene;

Dihydroxydiaryl ethers such as 2,2'-dihydroxydiphenyl ether, 3,3'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, 1,4-bis(3-hydroxyphenoxy)benzene, and 1,3-bis(4-hydroxyphenoxy)benzene;

2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A),
1,1-bis(4-hydroxyphenyl)propane,
2,2-bis(3-methyl-4-hydroxyphenyl)propane (i.e., bisphenol C),
2,2-bis(3-methoxy-4-hydroxyphenyl)propane,
2-(4-hydroxyphenyl)-2-(3-methoxy-4-hydroxyphenyl)propane,
1,1-bis(3-t-butyl-4-hydroxyphenyl)propane,
2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane,
2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane,
2-(4-hydroxyphenyl)-2-(3-cyclohexyl-4-hydroxyphenyl)propane,
α,α'-bis(4-hydroxyphenyl)-1,4-diisopropylbenzene,
1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene,
bis(4-hydroxyphenyl)methane,
bis(4-hydroxyphenyl)cyclohexylmethane,
bis(4-hydroxyphenyl)phenylmethane,
bis(4-hydroxyphenyl)(4-propenylphenyl)methane,
bis(4-hydroxyphenyl)diphenylmethane,
bis(4-hydroxyphenyl)naphthylmethane,
1,1-bis(4-hydroxyphenyl)ethane,
1,1-bis(4-hydroxyphenyl)-1-phenylethane,
1,1-bis(4-hydroxyphenyl)-1-naphthylethan,
1,1-bis(4-hydroxyphenyl)butane,
2,2-bis(4-hydroxyphenyl)butane,
2,2-bis(4-hydroxyphenyl)pentane,
1,1-bis(4-hydroxyphenyl)hexane,
2,2-bis(4-hydroxyphenyl)hexane,
1,1-bis(4-hydroxyphenyl)octane,
2,2-bis(4-hydroxyphenyl)octane,
4,4-bis(4-hydroxyphenyl)heptane,
2,2-bis(4-hydroxyphenyl)nonane,
1,1-bis(4-hydroxyphenyl)decane,
1,1-bis(4-hydroxyphenyl)dodecane,
Bis(hydroxyaryl)alkanes such as:

1,1-bis(4-hydroxyphenyl)cyclopentane,
1,1-bis(4-hydroxyphenyl)cyclohexane,
1,1-bis(4-hydroxyphenyl)-3,3-dimethylcyclohexane,
1,1-bis(4-hydroxyphenyl)-3,4-dimethylcyclohexane,
1,1-bis(4-hydroxyphenyl)-3,5-dimethylcyclohexane,
1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,
1,1-bis(4-hydroxy-3,5-dimethylphenyl)-3,3,5-trimethylcyclohexane,
1,1-bis(4-hydroxyphenyl)-3-propyl-5-methylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3-t-butyl-cyclohexane,
1,1-bis(4-hydroxyphenyl)-4-t-butyl-cyclohexane,
1,1-bis(4-hydroxyphenyl)-3-phenylcyclohexane,
1,1-bis(4-hydroxyphenyl)-4-phenylcyclohexane,
Bis(hydroxyaryl)cycloalkanes such as:

9,9-bis(4-hydroxyphenyl)fluorene,
Cardo structure-containing bisphenols such as 9,9-bis(4-hydroxy-3-methylphenyl)fluorene;

4,4'-dihydroxydiphenyl sulfide,
Dihydroxydiaryl sulfides such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide;
Dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide;
4,4'-dihydroxydiphenyl sulfone,
Dihydroxydiarylsulfones such as 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone;
etc.

Of these, bis(hydroxyaryl)alkanes are preferred, and bis(4-hydroxyphenyl)alkanes are particularly preferred. In particular, from the standpoints of impact resistance and heat resistance, 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A) and 2,2-bis(3-methyl-4-hydroxyphenyl)propane (i.e., bisphenol C) are preferred.
The aromatic dihydroxy compound may be used alone or in any combination of two or more in any ratio.

Among the monomers that are the raw materials for polycarbonate resin, examples of carbonate precursors include carbonyl halides and carbonate esters. Note that one type of carbonate precursor may be used, or two or more types may be used in any combination and ratio.

Specific examples of carbonyl halides include phosgene; haloformates such as bischloroformates of dihydroxy compounds and monochloroformates of dihydroxy compounds; and the like.

Specific examples of carbonate esters include diaryl carbonates such as diphenyl carbonate and ditolyl carbonate; dialkyl carbonates such as dimethyl carbonate and diethyl carbonate; biscarbonates of dihydroxy compounds, monocarbonates of dihydroxy compounds, and carbonates of dihydroxy compounds such as cyclic carbonates.

The method for producing the polycarbonate resin (A) is not particularly limited, and any method can be used. Examples include interfacial polymerization, melt transesterification, the pyridine method, ring-opening polymerization of cyclic carbonate compounds, and solid-phase transesterification of prepolymers. Among these, the interfacial polymerization and melt transesterification methods are preferred because they are more effective in improving resistance to moist heat, and the interfacial polymerization method is particularly preferred.

The molecular weight of the polycarbonate resin (A) is preferably 10,000 to 50,000, more preferably 10,000 to 40,000, particularly 10,000 to 30,000, or 10,000 to 26,000, and further 10,500 or more, 11,000 or more, particularly 11,500 or more, most preferably 12,000 or more, and further 24,000 or less, particularly preferably 20,000 or less. By making the viscosity average molecular weight equal to or more than the lower limit of the above range, the mechanical strength of the polycarbonate resin composition of the present invention can be further improved, and by making the viscosity average molecular weight equal to or less than the upper limit of the above range, the decrease in the flowability of the polycarbonate resin composition of the present invention can be suppressed and improved, and the molding processability can be improved to facilitate molding process.
Two or more kinds of polycarbonate resins having different viscosity average molecular weights may be mixed and used. In this case, polycarbonate resins having a viscosity average molecular weight outside the above-mentioned preferred range may be mixed.

The viscosity average molecular weight [Mv] means a value calculated from the Schnell viscosity formula, i.e., η = 1.23 × 10 ^-4 Mv ^0.83 , by determining the intrinsic viscosity [η] (unit: dl/g) at 25°C using methylene chloride as a solvent and an Ubbelohde viscometer. The intrinsic viscosity [η] is a value calculated from the specific viscosity [η _sp ] at each solution concentration [C] (g/dl) using the following formula:

In order to improve the appearance and flowability of the molded article, the polycarbonate resin (A) may contain a polycarbonate oligomer. The viscosity average molecular weight [Mv] of this polycarbonate oligomer is usually 1500 or more, preferably 2000 or more, and usually 9500 or less, preferably 9000 or less. Furthermore, it is preferable that the polycarbonate oligomer contained is 30% by mass or less of the polycarbonate resin (including the polycarbonate oligomer).

Furthermore, polycarbonate resin (A) may be not only virgin raw materials, but also polycarbonate resin regenerated from used products (so-called material recycled polycarbonate resin), and it is also preferable that it contains both virgin raw materials and recycled resin, or it may be made of recycled polycarbonate resin. The proportion of recycled polycarbonate resin in polycarbonate resin (A) is preferably 40% or more, 50% or more, 60% or more, or 80% or more, and it is particularly preferable that it is 100%.

[Graft copolymer (B)]
The graft copolymer (B) contained in the polycarbonate resin composition of the present invention is a graft copolymer containing an aromatic vinyl monomer component (b1), a cyanide vinyl monomer component (b2), and a diene rubber polymer component (b3). The graft copolymer (B) preferably comprises 40 to 80 mass% of the aromatic vinyl monomer component (b1), 10 to 30 mass% of the cyanide vinyl monomer component (b2), and 10 to 50 mass% of the diene rubber polymer component (b3), and may further contain 0 to 30 mass% of other monomer components (b4).

Examples of the aromatic vinyl monomer component (b1) in the graft copolymer (B) include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-t-butylstyrene, vinylnaphthalene, methoxystyrene, monobromostyrene, dibromostyrene, fluorostyrene, and tribromostyrene, with styrene being particularly preferred.
The proportion of the aromatic vinyl monomer component (b1) in the graft copolymer (B) is preferably in the range of 40 to 80 mass%, more preferably 45 mass% or more, even more preferably 50 mass% or more, particularly preferably 55 mass% or more, and more preferably 75 mass% or less, even more preferably 70 mass% or less, particularly preferably 65 mass% or less, based on 100 mass% of the graft copolymer (B).

Examples of the vinyl cyanide monomer component (b2) in the graft copolymer (B) include acrylonitrile and methacrylonitrile, with acrylonitrile being particularly preferred.
The proportion of the vinyl cyanide monomer component (b2) in the graft copolymer (B) is preferably in the range of 10 to 30% by mass, more preferably 12% by mass or more, even more preferably 14% by mass or more, particularly preferably 15% by mass or more, and more preferably 28% by mass or less, even more preferably 26% by mass or less, particularly preferably 25% by mass or less, based on 100% by mass of the graft copolymer (B).

As the diene rubber polymer component (b3) of the graft copolymer (B), for example, a rubber component such as polybutadiene, polyisoprene, or styrene-butadiene copolymer is used, and the proportion of the diene rubber polymer component (b3) in the graft copolymer (B) is preferably in the range of 10 to 50 mass% of 100 mass% of the graft copolymer (B), more preferably 13 mass% or more, even more preferably 14 mass% or more, particularly preferably 15 mass% or more, and more preferably 45 mass% or less.

Furthermore, it may be a copolymer of other monomer components (b4) copolymerizable with these. In this case, examples of the other copolymerizable vinyl monomers include maleimide-based monomers such as maleimide, N-methylmaleimide, N-cyclohexylmaleimide, and N-phenylmaleimide, acrylamide-based monomers such as acrylamide and N-methylacrylamide, unsaturated acid anhydrides such as maleic anhydride and itaconic anhydride, unsaturated acids such as acrylic acid and methacrylic acid, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and methoxypolyethylene glycol methacrylate.
The proportion of the other monomer component (b4) in the graft copolymer (B) is preferably in the range of 0 to 30% by mass, more preferably 20% by mass or less, even more preferably 10% by mass or less, even more preferably 5% by mass or less, particularly preferably 3% by mass or less, and even more preferably 2% by mass or less, based on 100% by mass of the graft copolymer (B).

Specific examples of the graft copolymer (B) include acrylonitrile-butadiene-styrene graft copolymer, acrylonitrile-butadiene-styrene-α-methylstyrene graft copolymer, and acrylonitrile-ethylene-propylene-diene-styrene copolymer, among which acrylonitrile-butadiene-styrene graft copolymer (ABS resin) is particularly preferred.

The graft copolymer (B) is usually produced by a method such as bulk polymerization, solution polymerization, suspension polymerization, or emulsion polymerization, and any method can be used.

The content of the graft copolymer (B) is 10 to 45% by mass, based on 100% by mass of the total of the polycarbonate resin (A) and the graft copolymer (B), and is preferably 12% by mass or more, more preferably 15% by mass or more, preferably 42% by mass or less, and more preferably 40% by mass or less. By having the content in such a range, the resin composition can be made excellent in heat resistance and fluidity. If the amount of the graft copolymer (B) exceeds 45% by mass, the heat resistance decreases, and if it is less than 10% by mass, the fluidity decreases.

[Triaryl phosphate (C)]
The polycarbonate resin composition of the present invention contains a triaryl phosphate (C) represented by general formula (1). Here, the aryl group means a group containing an aromatic group, and particularly preferably means a phenyl group.

In formula (1), R ¹ to R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and as the alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 8 carbon atoms is preferable, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group, or an octyl group. Among these, an alkyl group having 1 to 6 carbon atoms, particularly an alkyl group having 1 to 4 carbon atoms, is preferable.

In formula (1), when two or more of R ¹ to R ⁵ on the three aromatic rings are alkyl groups, the alkyl groups may be the same or different from each other.
As the triaryl phosphate (C), in the formula (1), at least one of R ¹ to R ⁵ on each aromatic ring is preferably an alkyl group having 1 to 12 carbon atoms.
More preferably, R ¹ and R ³ on each aromatic ring are an alkyl group having 1 to 12 carbon atoms, and R ² , R ⁴ and R ⁵ on each aromatic ring are hydrogen atoms.

Specific examples of triaryl phosphate (C) include triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, cresyl-2,6-dixylenyl phosphate, dicresyl phenyl phosphate, ethyl phenyl diphenyl phosphate, diethyl phenyl phosphate, propyl phenyl diphenyl phosphate, dipropyl phenyl phosphate, tripropyl phenyl phosphate, butyl phenyl diphenyl phosphate, dibutyl phenyl phenyl phosphate, and tributyl phenyl phosphate.

The triaryl phosphate (C) is preferably triphenyl phosphate or tris(4-t-butylphenyl) phosphate, and more preferably a compound represented by formula (1) in which R ¹ and R ³ on each aromatic ring are t-butyl groups and R ² , R ⁴ and R ⁵ on each aromatic ring are hydrogen atoms, with tris(2,4-di-t-butylphenyl) phosphate being particularly preferred.

Triaryl phosphate (C) may be used alone or in combination of two or more types.

The content of triaryl phosphate (C) is 0.001 to 0.3 parts by mass per 100 parts by mass of the total of polycarbonate resin (A) and graft copolymer (B). A resin composition containing such an amount in combination with a specific amount of triaryl phosphite (D) in a specific ratio exhibits excellent weather resistance and excellent hue. The content of triaryl phosphate (C) is preferably 0.002 parts by mass or more, more preferably 0.003 parts by mass or more, 0.004 parts by mass or more, particularly preferably 0.005 parts by mass or more, and also preferably 0.25 parts by mass or less, more preferably 0.2 parts by mass or less, 0.15 parts by mass or less, 0.13 parts by mass or less, particularly preferably 0.1 parts by mass or less.

[Triaryl phosphite (D)]
The polycarbonate resin composition of the present invention further contains a triaryl phosphite (D). Here, the aryl group means a group containing a monocyclic or polycyclic aromatic group, and particularly preferably means a phenyl group.

Preferable examples of triaryl phosphites (D) include triphenyl phosphite, tris(p-tolyl)phosphite, tris(p-nonylphenyl)phosphite, tris(mononyl/dinonyl phenyl)phosphite, tris(2,4-di-t-butylphenyl)phosphite, tris(naphthyl)phosphite, tris(p-chlorophenyl)phosphite, tris(p-fluorophenyl)phosphite, diphenylbenzylphosphine, diphenyl(p-hydroxyphenyl)phosphite, diphenyl-1,4-dihydroxyphenyl-2-phosphite, and phenylnaphthylbenzylphosphine, with triphenyl phosphite and tris(2,4-di-t-butylphenyl)phosphite being particularly preferred.

The content of triaryl phosphite (D) is 0 to 0.3 parts by mass relative to 100 parts by mass in total of polycarbonate resin (A) and graft copolymer (B). By containing triaryl phosphate (C) in combination with the triaryl phosphate (D)/(C) in a ratio of 0 to 4, high weather resistance can be achieved. The content of aryl phosphine is preferably more than 0 parts by mass and 0.3 parts by mass or less, more preferably 0.005 parts by mass or more, particularly preferably 0.008 parts by mass or more, particularly preferably 0.01 parts by mass or more, and more preferably 0.25 parts by mass or less, particularly preferably 0.2 parts by mass or less, 0.15 parts by mass or less, 0.1 parts by mass or less, 0.05 parts by mass or less, particularly preferably 0.04 parts by mass or less.
The mass ratio (D)/(C) is preferably 0 or more and 4 or less, more preferably 0.01 or more and 3.5 or less, and further preferably 0.1 or more and 3 or less.

[Compound (E) having a phenol structure]
The polycarbonate resin composition of the present invention also preferably contains a compound (E) having a phenol structure.
The compound (E) having a phenol structure is a compound in which a hydroxy group is directly bonded to a benzene ring, and in the present invention, it is 4-t-butylphenol, 2,4-di-t-butylphenol, 4-α-cumylphenol, or bisphenol A. Among these, 4-t-butylphenol, 4-α-cumylphenol, or 4-t-butylphenol is more preferred.
The compound (E) having a phenol structure may contain one type alone or two or more types.

When the compound (E) having a phenol structure is contained, the content is preferably 0.001 to 0.03 parts by mass per 100 parts by mass of the polycarbonate resin (A) and the graft copolymer (B) combined. When two or more types of compound (D1) having a phenol structure are contained, the content is the total amount of them. By containing such an amount of triaryl phosphate (C) and triaryl phosphite (D) in the polycarbonate resin (A) and the graft copolymer (B), the weather resistance can be further improved.

When the compound (E) having a phenol structure is contained, the content is preferably 0.0015 parts by mass or more, more preferably 0.002 parts by mass or more, 0.003 parts by mass or more, and particularly preferably 0.004 parts by mass or more, and is also preferably 0.025 parts by mass or less, more preferably 0.02 parts by mass or less, 0.015 parts by mass or less, and particularly preferably 0.013 parts by mass or less, per 100 parts by mass of the polycarbonate resin (A) and the graft copolymer (B) combined.

When 4-t-butylphenol is contained as the compound (E) having a phenol structure, the content is preferably 0.0012 to 0.01 parts by mass, and more preferably 0.002 to 0.003 parts by mass, per 100 parts by mass of the total of (A) and (B).
When 2,4-di-t-butylphenol is contained as the compound (E) having a phenol structure, the content thereof is preferably 0.0012 to 0.01 parts by mass, and more preferably 0.002 to 0.003 parts by mass, per 100 parts by mass of the total of (A) and (B).
When 4-α-cumylphenol is contained, the content is preferably 0.0012 to 0.01 part by mass, and more preferably 0.002 to 0.003 part by mass, per 100 parts by mass of the total of (A) and (B).
When bisphenol A is contained as the compound (E) having a phenol structure, the content thereof is preferably 0.002 to 0.03 parts by mass, more preferably 0.004 to 0.01 parts by mass, per 100 parts by mass of the total of (A) and (B).

4-t-butylphenol, 2,4-di-t-butylphenol, 4-α-cumylphenol, or bisphenol A may be present in a free state, either as a by-product or used in the production of polycarbonate resin (A), or derived from recycled polycarbonate resin, and the amounts of these are also included in the amount of compound (E) having a phenol structure.

[Phenol-based antioxidants]
The polycarbonate resin composition of the present invention preferably further contains a phenol-based antioxidant.
Preferred examples of the phenol-based antioxidant include hindered phenol-based antioxidants. Specific examples thereof include pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, thiodiethylene bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-hexane-1,6-diylbis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide], 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphate, 3,3',3",5,5',5"-hexa-t-butyl-a,a',a"-(mesitylene-2,4, 6-triyl)tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene)bis[3-(5-t-butyl-4-hydroxy-m-tolyl)propionate], hexamethylene bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,6-di-t-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol, 2-[1-(2-hydroxy-3,5-di-t-pentylphenyl)ethyl]-4,6-di-t-pentylphenyl acrylate, and the like.

Among these, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] and octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate are particularly preferred.
The phenol-based antioxidant may be contained alone or in any combination and ratio of two or more kinds.

When a phenolic antioxidant is contained, the content is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 1 part by mass or less, more preferably 0.5 parts by mass or less, per 100 parts by mass of the total of the polycarbonate resin (A) and the graft copolymer (B). By making the content of the phenolic antioxidant equal to or more than the lower limit of the above range, the effect of the phenolic antioxidant can be sufficiently obtained. Furthermore, by making the content of the phenolic antioxidant equal to or less than the upper limit of the above range, the effect does not plateau, and it is economical.

[Release agent]
The resin composition of the present invention also preferably contains a release agent.
Examples of the release agent include aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15,000, and polysiloxane-based silicone oils.

Examples of aliphatic carboxylic acids include saturated or unsaturated aliphatic mono-, di- or tri-carboxylic acids. Here, aliphatic carboxylic acids also include alicyclic carboxylic acids. Among these, preferred aliphatic carboxylic acids are mono- or di-carboxylic acids having 6 to 36 carbon atoms, and more preferred are saturated aliphatic mono-carboxylic acids having 6 to 36 carbon atoms. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, tetralinic acid, montanic acid, adipic acid, and azelaic acid.

As the aliphatic carboxylic acid in the ester of an aliphatic carboxylic acid and an alcohol, for example, the same aliphatic carboxylic acid as described above can be used. On the other hand, as the alcohol, for example, a saturated or unsaturated monohydric or polyhydric alcohol can be used. These alcohols may have a substituent such as a fluorine atom or an aryl group. Among these, a monohydric or polyhydric saturated alcohol having 30 or less carbon atoms is preferred, and an aliphatic saturated monohydric alcohol or an aliphatic saturated polyhydric alcohol having 30 or less carbon atoms is more preferred. Here, the term aliphatic is used to include alicyclic compounds.

Specific examples of such alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, dipentaerythritol, etc.

The above esters may contain aliphatic carboxylic acids and/or alcohols as impurities. The above esters may be pure substances or mixtures of multiple compounds. Furthermore, the aliphatic carboxylic acids and alcohols that combine to form an ester may each be used alone or in any combination and ratio of two or more kinds.

Specific examples of esters of aliphatic carboxylic acids and alcohols include beeswax (a mixture mainly composed of myricyl palmitate), stearyl stearate, behenyl behenate, stearyl behenate, glycerin monopalmitate, glycerin monostearate, glycerin distearate, glycerin tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate, etc.

Examples of aliphatic hydrocarbons having a number average molecular weight of 200 to 15,000 include liquid paraffin, paraffin wax, microwax, polyethylene wax, Fischer-Tropsch wax, and α-olefin oligomers having 3 to 12 carbon atoms. The aliphatic hydrocarbons herein also include alicyclic hydrocarbons. These hydrocarbons may be partially oxidized.
Among these, paraffin wax, polyethylene wax, or a partial oxide of polyethylene wax is preferred, and paraffin wax and polyethylene wax are more preferred.
The number average molecular weight of the aliphatic hydrocarbon is preferably 5,000 or less.
The aliphatic hydrocarbon may be a single substance, but a mixture of substances having various constituent components and molecular weights can also be used as long as the main component is within the above range.

Examples of polysiloxane-based silicone oils include dimethyl silicone oil, methylphenyl silicone oil, diphenyl silicone oil, and fluorinated alkyl silicone.

The above-mentioned release agents may be contained in one type, or in any combination and ratio of two or more types.

The content of the release agent is usually 0.001 parts by mass or more, preferably 0.01 parts by mass or more, and usually 2 parts by mass or less, preferably 1 part by mass or less, and more preferably 0.5 parts by mass or less, per 100 parts by mass of the total of the polycarbonate resin (A) and the graft copolymer (B). If the content of the release agent is less than the lower limit of the above range, the release effect may be insufficient, and if the content of the release agent is more than the upper limit of the above range, there is a possibility that the hydrolysis resistance may decrease and the mold may be contaminated during injection molding.

[Ultraviolet absorber]
The polycarbonate resin composition of the present invention also preferably contains an ultraviolet absorber.
Examples of the ultraviolet absorber include inorganic ultraviolet absorbers such as cerium oxide and zinc oxide; and organic ultraviolet absorbers such as benzotriazole compounds, benzophenone compounds, salicylate compounds, cyanoacrylate compounds, triazine compounds, oxalilide compounds, malonic acid ester compounds, and hindered amine compounds. Among these, organic ultraviolet absorbers are preferred, and benzotriazole compounds are more preferred. By selecting an organic ultraviolet absorber, the transparency and mechanical properties of the resin composition of the present invention can be improved.

Specific examples of benzotriazole compounds include, for example, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-[2'-hydroxy-3',5'-bis(α,α-dimethylbenzyl)phenyl]-benzotriazole, 2-(2'-hydroxy-3',5'-di-t-butyl-phenyl)-benzotriazole, 2-(2'-hydroxy-3',5'-di-t-butyl-phenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-t-butyl-phenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-t-butyl-phenyl)-5-chlorobenzotriazole, amyl)-benzotriazole, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], etc., among which 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole and 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol] are preferred, and 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole is particularly preferred.

Specific examples of benzophenone compounds include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-n-dodecyloxybenzophenone, bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane, 2,2'-dihydroxy-4-methoxybenzophenone, and 2,2'-dihydroxy-4,4'-dimethoxybenzophenone.

Specific examples of the salicylate compound include phenyl salicylate, 4-t-butylphenyl salicylate, and the like.
Specific examples of the cyanoacrylate compound include ethyl-2-cyano-3,3-diphenylacrylate, 2-ethylhexyl-2-cyano-3,3-diphenylacrylate, and the like.
Specific examples of the oxanilide compounds include 2-ethoxy-2'-ethyloxalic acid bis-arylide.
As the malonic acid ester compound, 2-(alkylidene)malonic acid esters are preferred, and 2-(1-arylalkylidene)malonic acid esters are more preferred.

The content of the ultraviolet absorber, when contained, is usually 0.05 parts by mass or more, preferably 0.1 parts by mass or more, and usually 1 part by mass or less, preferably 0.5 parts by mass or less, based on 100 parts by mass in total of the polycarbonate resin (A) and the graft copolymer (B). If the content of the ultraviolet absorber is less than the lower limit of the above range, the effect of improving weather resistance and light resistance may be insufficient, and if the content of the ultraviolet absorber exceeds the upper limit of the above range, mold deposits or the like may occur, causing mold contamination.
The ultraviolet absorbing agent may be contained alone or in any combination and ratio of two or more kinds.

[Additives, etc.]
The polycarbonate resin composition of the present invention may contain additives other than those described above, such as fluorescent whitening agents, pigments (including titanium oxide, etc.), dyes, flame retardants, impact resistance improvers, plasticizers, compatibilizers, etc. These additives may be contained alone or in combination of two or more.

The polycarbonate resin (A) and the graft copolymer (B) may contain other resins. Examples of the other resins include thermoplastic polyester resins such as polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate; styrene-based resins such as polystyrene resin (GPPS), high impact polystyrene resin (HIPS), and acrylonitrile-styrene copolymer (AS resin); polyolefin resins such as polyethylene resin and polypropylene resin; polyamide resin; polyimide resin; polyetherimide resin; polyurethane resin; polyphenylene ether resin; polyphenylene sulfide resin; polysulfone resin; and polymethacrylate resin.
When other resins than the polycarbonate resin (A) and the graft copolymer (B) are contained, the content thereof is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, still more preferably 5 parts by mass or less, and particularly preferably 3 parts by mass or less, per 100 parts by mass of the total of the polycarbonate resin (A) and the graft copolymer (B).

In order to confirm the effects of the polycarbonate resin composition of the present invention, polycarbonate resin compositions were prepared as follows, but the present invention should not be construed as being limited to the following examples.
The components used are as shown in Table 1 below.

(Examples 1 to 19, Comparative Examples 1 to 8)
The above-mentioned components were blended in the ratios (parts by mass) shown in Table 2 below, fed to a twin-screw extruder ("TEM26SX" manufactured by Toshiba Machine Co., Ltd.), kneaded under conditions of a screw rotation speed of 150 rpm, a discharge rate of 25 kg/hour, and a barrel temperature of 260° C., and extruded in the form of strands from the tip of the extrusion nozzle. The strands were quenched in a water tank and cut and pelletized using a pelletizer to obtain pellets of a polycarbonate resin composition.

<MVR>
The pellets obtained by the above method were dried at 100° C. for 5 hours, and then MVR (melt volume rate, unit: g/10 min) was measured in accordance with ISO 1133 at a measurement temperature of 250° C. and a load of 2.16 kgf.

<Charpy notched strength>
The pellets obtained by the above method were dried at 100°C for 5 hours, and then injection molded in an injection molding machine ("NEX80III" manufactured by Nissei Plastic Industrial Co., Ltd.) under conditions of a cylinder temperature of 260°C and a mold temperature of 60°C to produce ISO multipurpose test pieces (4 mmt).
Using the obtained ISO multipurpose test piece (4 mmt), the notched Charpy strength (unit: kJ/m ² ) was measured at a temperature of 23° C. in accordance with ISO standard 179.

<Heat resistance DTUL (deflection temperature under load)>
Based on ISO 75-1 and ISO 75-2, a constant bending load (1.80 MPa) was applied in the flatwise direction to the center of a 4 mm x 10 mm ISO multipurpose test piece (4 mmt), and the temperature was raised at a constant rate to measure the temperature (unit: ° C.) when the strain at the center reached 0.34 mm.

<Weather resistance (ΔE)>
The obtained pellets were injection molded using a Toshiba Machine Co., Ltd. injection molding machine "EC50SXII" under conditions of a cylinder temperature of 260°C and a mold temperature of 60°C to obtain a plate-shaped molded product having a length of 90 mm, a width of 60 mm and a thickness of 2 mm.
The obtained plate-shaped molded product was subjected to a light fastness treatment using a xenon weather tester (ATLAS, "Ci4000") with light of wavelength 300-400 nm under the conditions of temperature: 89°C, irradiation intensity: approximately 55 W/ ^m2 , and treatment time: 100 hours (treatment time of 300 hours for titanium oxide-added systems). The hue before and after the light fastness treatment was measured using Nippon Denshoku Industries Co., Ltd.'s "SE6000" under D65, 10° field of view, and reflective conditions, and the color difference ΔE was calculated to evaluate the light fastness.
ΔE is preferably 7.5 or less, and in the case of a titanium oxide-added system, it is preferably 1.4 or less.

The above evaluation results are shown in Table 2 below.

The polycarbonate resin composition of the present invention has high weather resistance, and is excellent in impact resistance, heat resistance, and fluidity (moldability), making it suitable for use in a variety of molded products.

Claims (10)

per 100 parts by mass in total of (A) and (B) containing 55 to 90% by mass of a polycarbonate resin (A) having a viscosity average molecular weight of 17,500 to 30,000, and 10 to 45% by mass of a graft copolymer (B) containing an aromatic vinyl monomer component (b1), a vinyl cyanide monomer component (b2), and a diene rubber polymer component (b3),
A polycarbonate resin composition comprising 0.001 to 0.3 parts by mass of a triaryl phosphate (C) represented by the following general formula (1), and 0 to 0.3 parts by mass of a triaryl phosphite (D), and the mass ratio (D)/(C) of the contents of the triaryl phosphite (D) to the triaryl phosphate (C) is 0 or more and 4 or less:

[In formula (1), R ¹ to R ⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.] 2. The polycarbonate resin composition according to claim 1, wherein in formula (1), at least one of R ¹ to R ⁵ on each aromatic ring is an alkyl group having 1 to 12 carbon atoms. 2. The polycarbonate resin composition according to claim 1, wherein in formula (1), R ¹ and R ³ on each aromatic ring are alkyl groups having 1 to 12 carbon atoms, and R ² , R ⁴ and R ⁵ on each aromatic ring are hydrogen atoms. 4. The polycarbonate resin composition according to claim 3, wherein in formula (1), R ¹ and R ³ on each aromatic ring are tert-butyl groups, and R ² , R ⁴ and R ⁵ on each aromatic ring are hydrogen atoms. The polycarbonate resin composition according to claim 1, wherein the triaryl phosphate (C) contains at least one of triphenyl phosphate, tris(2,4-di-t-butylphenyl) phosphate, and tris(4-t-butylphenyl) phosphate. The polycarbonate resin composition according to claim 1, which contains more than 0 parts by mass and 0.3 parts by mass or less of triaryl phosphite (D) per 100 parts by mass of the total of (A) and (B). The polycarbonate resin composition according to claim 1, wherein the mass ratio (D)/(C) of the content of triaryl phosphate (C) to triaryl phosphite (D) is greater than 0 and less than or equal to 4. Pellets of the polycarbonate resin composition according to any one of claims 1 to 7. A molded article made of the polycarbonate resin composition according to any one of claims 1 to 7. A molded article comprising pellets of the polycarbonate resin composition according to claim 8.