JP2000053854A - Flame-retarded polycarbonate resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition which can give a molded article excellent in mechanical strengths, light resistance, heat resistance, surface appearance, light shielding properties, and light reflectivity by mixing a polycarbonate resin with titanium oxide, a phosphorus-containing flame retardant, a multilayer structure elastomer, and a polytetrafluoroethylene capable of being fibrillated in a specified ratio. SOLUTION: This composition comprises 100 pts.wt. polycarbonate resin, 0.1-50 pts.wt. titanium oxide, 0.5-40 pts.wt. phosphorus-containing flame retardant, 0.1-10 pts.wt. multilayer structure elastomer composed of a core made from a crosslinked rubbery polymer comprising an alkyl (meth)acrylate and having a glass transition temperature of 0 deg.C or below and an outermost shell made from an alkyl (meth)acrylate and 0.01-1 pt.wt. polytetrafluoroethylene capable of being fibrillated. The phosphorus-containing flame retardant is desirably a compound of formula I or II (wherein R1 to R7 are each a 1-6C alkyl or an (alkyl-substituted) 6-20C aryl; h, j, k, p, q, r, and s are each 0 or 1; m is 1-5; and X is an arylene).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a flame-retardant polycarbonate resin composition. Specifically, it has excellent mechanical strength, light resistance, and heat resistance, as well as various properties such as surface appearance, flame retardancy, drip resistance, heat stability when molten, light shielding, and light reflectance. The present invention relates to a flame-retardant polycarbonate resin composition that can be suitably used for a wide range of applications such as lighting devices, liquid crystal backlights, and electric components.

[0002]

2. Description of the Related Art Conventionally, it has been widely practiced to add a titanium oxide to a polycarbonate resin for coloring or imparting a light-shielding property. However, on the surface of titanium oxide, there are chemically active sites, which are melt-kneaded and melt-molded,
To promote the deterioration of the polycarbonate resin, the original excellent mechanical properties of the polycarbonate resin are damaged,
There was a problem that the molded product was discolored.

As methods for suppressing discoloration of the polycarbonate resin due to titanium oxide, a method of mixing a polyorganohydrogen siloxane (see Japanese Patent Publication No. 63-26140) and a method of mixing a polyhydrocarbon oxysiloxane (see Japanese Patent Publication No. 31513/1988) And a method of mixing a silane coupling agent having an amino group or an epoxy group (see Japanese Patent Publication No. 3-2189).

In recent years, from the viewpoint of fire safety, there has been a strong demand for flame-retardant synthetic resins used in electric parts and the like.
It is required to exhibit a high degree of flame retardancy as defined in the UL standard and not to cause dripping of combustion products. Polycarbonate resins are widely used for electric parts and the like, and various flame retardant technologies have been proposed. Hitherto, in order to make a polycarbonate resin flame-retardant, a method of mainly adding a halogen compound has been adopted. However, in recent years, problems such as environmental pollution by halogen compounds,
In addition, in order to improve the thermal stability of a resin composition to which a halogen compound has been added, a technique of adding a non-halogen compound to make the composition flame-retardant has been studied.

When making a polycarbonate resin flame-retardant,
A technique of adding a phosphate compound in place of a halogen compound has been proposed (see JP-A-10-1600). The technique proposed here involves coloring the base resin and blending titanium oxide for the purpose of imparting light-shielding properties to the obtained molded article, and blending a phosphate ester-based flame retardant to make it flame-retardant. There is a disadvantage that the mechanical strength, which is an excellent property of the polycarbonate resin, is reduced. In addition, reflectors such as liquid crystal backlights receive long-term light or heat radiation from various light sources such as fluorescent lamps. However, there is also a disadvantage that the temperature is reduced.

[0006]

The polycarbonate resin has excellent flame resistance, non-dripping properties, heat stability upon melting, etc., without sacrificing the excellent mechanical strength, light resistance and heat resistance. The fact is that a polycarbonate resin composition from which a molded article having excellent appearance, light-shielding properties and light reflectivity can be obtained has not yet been obtained. The objects of the present invention are as follows. 1. To provide a flame-retardant polycarbonate resin composition excellent in mechanical strength, light resistance and heat resistance. 2. An object of the present invention is to provide a flame-retardant polycarbonate resin composition from which a molded article having excellent surface appearance, light-shielding properties and light reflectance can be obtained.

[0007]

In order to solve the above-mentioned problems, in the present invention, 0.1 to 50 parts by weight of titanium oxide (B), 100 parts by weight of polycarbonate resin (A), and phosphorus-based flame retardant (C A) a crosslinked alkyl (meth) having a glass transition point (Tg) of 0 to 40 ° C.
0.1 to 10 parts by weight of a multilayered elastic body (D) having an inner core of a rubber-like polymer made of acrylate and an outermost shell layer of alkyl (meth) acrylate, and fibril-forming polytetrafluoroethylene (E) A) providing a flame-retardant polycarbonate resin composition, characterized in that the composition is blended in an amount of 0.01 to 1 part by weight;

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The polycarbonate resin (A) in the flame-retardant polycarbonate resin composition according to the present invention (hereinafter sometimes referred to as component (A)) is a base resin of the flame-retardant polycarbonate resin composition, and is a dihydric phenol. And a carbonate precursor by a solution method or a melting method. Representative dihydric phenols include 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl)
Ethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3 -Methylphenyl) propane, bis (4-hydroxyphenyl) sulfide, bis (4
-Hydroxyphenyl) sulfone and the like.

Preferred dihydric phenols are bis (4-hydroxyphenyl) alkanes, especially bisphenol A
Is the main raw material. Examples of the carbonate precursor include carbonyl halide, carbonyl ester, and haloformate. Specific examples thereof include phosgene, diphenyl carbonate, dihaloformate of divalent phenol, and a mixture thereof. The dihydric phenol for producing the polycarbonate resin may be a single type or a mixture of two or more types.

The viscosity average molecular weight of the polycarbonate resin for molding is generally in the range of 10,000 to 100,000, but from the viewpoint of moldability and physical properties of the molded product, it is in the range of 15,000 to 60,000. Are preferred. When producing a polycarbonate having a viscosity average molecular weight in the above range, a molecular weight modifier,
It is preferable to use a branching agent for improving processability, a catalyst for accelerating the reaction, and the like, as appropriate, in combination.

The titanium oxide (B) (hereinafter sometimes referred to as component (B)) in the flame-retardant polycarbonate resin composition according to the present invention improves the whiteness, light-shielding properties, light reflectance, etc. of the molded article. Things. Titanium oxide is manufactured by the sulfuric acid method or the chlorine method, but titanium oxide manufactured by the sulfuric acid method is inferior to titanium oxide manufactured by the chlorine method in terms of whiteness. It is suitable. Titanium oxide has a rutile form and an anatase form, and the rutile form is excellent in terms of whiteness, light reflectivity and light resistance. Therefore, a rutile form is preferable.

If the surface treatment is not performed, titanium oxide as the component (B) causes a decrease in the molecular weight and discoloration of the polycarbonate resin as a base when the resin composition is melted and kneaded at a high temperature. Are preferred. The surface treatment of titanium oxide is performed by one or more inorganic surface treating agents selected from alumina hydrate and silicic acid hydrate.

It is preferable that these titanium oxides are further treated with an organic surface treating agent, particularly a silicon compound. Examples of the silicon-based compound include polyorganohydrogensiloxane (see Japanese Patent Publication No. 63-26140) and polyhydrocarbon siloxane (see Japanese Patent Publication No. 63-3).
No. 1513) and a silane coupling agent (see Japanese Patent Publication No. 3-2189).

The titanium oxide as the component (B) has an average particle diameter of 0.05 to 0.50 μm.
Even if the average particle size is less than 0.05 or more than 0.50 μm, the molded article obtained from the resin composition is inferior in light-shielding properties and light reflectance, and when it exceeds 0.50 μm, the surface of the molded article is further roughened. Or the impact strength is undesirably reduced. In the above range, 0.10 to 0.40 μm is preferable, and 0.15 to 0.35 μm is particularly preferable.

The mixing ratio of titanium oxide in the flame-retardant polycarbonate resin composition according to the present invention is selected in the range of 0.1 to 50 parts by weight of titanium oxide based on 100 parts by weight of the base polycarbonate resin. If the compounding ratio of titanium oxide is less than 0.1 part by weight, the obtained molded article is inferior in light-shielding properties, and if it exceeds 50 parts by weight, the impact strength is greatly reduced, and neither is preferable.

The phosphorus-based flame retardant (C) in the flame-retardant polycarbonate resin composition according to the present invention (hereinafter sometimes referred to as the component (C)) is a compound having a phosphorus atom in the molecule, and is preferably The following general formula [I] or [II]
And a phosphorus compound represented by the formula:

[0017]

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[0018]

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Specific examples of the phosphorus-based flame retardant represented by the general formula [I] include triphenyl phosphate, tricresyl phosphate,
Examples include diphenyl-2-ethylcrisyl phosphate, tri (isopropylphenyl) phosphate, diphenyl methylphosphonic acid, diethyl phenylphosphonic acid, diphenylcresyl phosphate, and tributyl phosphate. The phosphorus compound represented by the general formula [I] can be obtained by a known method.
It can be produced from phosphorus oxychloride or the like.

X of the arylene group in the general formula [II]
Is a group derived from a dihydroxy compound such as resorcinol, hydroquinone, and bisphenol A. As the phosphorus-based flame retardant represented by the general formula [II],
m may be a condensed phosphate ester of 1 to 5, and m may be a single condensed phosphate ester, or m may be a mixture of different condensed phosphate esters. In the case of a mixture, the average value of m of the mixture may be 1 to 5.

Specific examples of the phosphorus-based flame retardant represented by the general formula [II] include, when the dihydroxy compound is resorcinol, phenylresorcinol-polyphosphate;
Cresyl resorcinol polyphosphate, phenyl
Cresyl resorcinol polyphosphate, xylyl
Resorcinol polyphosphate, phenyl-Pt-butylphenylresorcinol polyphosphate, phenyl
Isopropylphenyl resorcinol polyphosphate,
Cresyl, xylyl, resorcinol, polyphosphatephenyl, isopropylphenyl, diisopropylphenyl, resorcinol polyphosphate and the like.

The compounding amount of the phosphorus-based flame retardant as the component (C) in the flame-retardant polycarbonate resin composition according to the present invention is 0.5 to 40 parts by weight with respect to 100 parts by weight of the substrate polycarbonate resin. If the amount of the phosphorus-based flame retardant is less than 0.5 part by weight, the flame retardancy of the resin composition is insufficient, and if it exceeds 40 parts by weight, the mechanical properties of a molded article obtained from the resin composition deteriorates. All are not preferred. The content of the phosphorus-based flame retardant is 0.8 in the above range.
It is preferably from 30 to 30 parts by weight, and particularly preferably from 1 to 25 parts by weight.

The multilayered elastic body (D) in the flame-retardant polycarbonate resin composition according to the present invention (hereinafter sometimes referred to as the component (D)) functions as an impact improver and has a glass transition point (Tg). ) Is a multilayered elastic body having an inner core of a rubbery polymer made of a crosslinked alkyl (meth) acrylate having a temperature of 0 ° C. or lower and an outermost shell layer of the alkyl (meth) acrylate. As impact improvers,
It is also known that the inner core contains butadiene as a component, but this is not preferable because it discolors with light or heat. When the outer shell layer is composed of an alkyl (meth) acrylate, the molded article becomes excellent in light resistance, which is preferable.

The proportion of the component (D) in the flame-retardant polycarbonate resin composition according to the present invention is selected in the range of 0.1 to 20 parts by weight based on 100 parts by weight of the base polycarbonate resin. When the amount of the component (D) is less than 0.1 part by weight, the physical properties of the molded article obtained from the resin composition, particularly the impact strength is not improved, while when the amount is more than 10 parts by weight, the strength and heat resistance are reduced, Neither is preferred.
A particularly preferred mixing ratio of the component (D) is 1 to 10 parts by weight.

The fibril-forming polytetrafluoroethylene (PTFE) (E) (hereinafter sometimes referred to as the component (E)) in the flame-retardant polycarbonate resin composition according to the present invention is characterized in that it does not drip when a molded article is burned. It works to improve. The polytetrafluoroethylene as the component (E) has a fibril-forming ability.
It is classified as type 3 in the TM standard. PTFE having a fibril-forming ability can be prepared, for example, by adding tetrafluoroethylene to an aqueous solvent in the presence of sodium, potassium or ammonium-oxysulfide in the range of 1 to 100.
Under a pressure of psi, a temperature of 0 to 200 ° C., preferably 20 to 200 ° C.
It is obtained by polymerizing at 100 ° C. PTFE having no fibril forming ability does not achieve the object of the present invention. Examples of such fibril-forming PTFE include those having a molecular weight of 1,000,000 or more, preferably 2,000,000 or more.

Fibril-forming PT as component (E)
The mixing ratio of FE is 100
It is selected in the range of 0.01 to 1 part by weight based on part by weight. When the blending ratio of the component (E) is less than 0.01 part by weight, it is insufficient to impart non-dripping property when burning a molded article, and when it exceeds 1 part by weight, polycarbonate and the resin composition Not only impairs the mechanical properties of the molded article, but also causes a roughening phenomenon on the surface of the molded article, which is not preferable.
The particularly preferable compounding ratio of the component (E) is 0.03 to 0.1.
5 parts by weight.

The flame-retardant polycarbonate resin composition according to the present invention contains, as a stabilizer, an organophosphite compound (F) represented by the following general formula [III] ｛(F)
It is preferable to mix｝ which may be called a component.

[0028]

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The mixing ratio of the organophosphite compound as the component (F) depends on the polycarbonate resin 1
It is preferably selected in the range of 0.005 to 1.0 part by weight, particularly preferably 0.01 to 0.01 part by weight.
0.5 part by weight.

The flame-retardant polycarbonate resin composition according to the present invention is obtained by adding the components (B) to (E) to the component (A) of the base resin, and preferably further adding the component (F).
Although they are blended in predetermined amounts, various types and amounts of various resin additives that do not impair the object of the present invention can be blended. Examples of the resin additive that can be blended include a release agent, a fluorescent brightener, a heat stabilizer, a light stabilizer, an antioxidant, an ultraviolet absorber, a coloring agent such as a dye and a pigment, and an inorganic filler. In particular, an ultraviolet absorber, a fluorescent whitening agent, and the like are extremely useful for achieving the object of maintaining the reflection characteristics, which are the characteristics of the flame-retardant polycarbonate composition according to the present invention, for a long period of time. Furthermore, since it contains a phosphate, titanium oxide, and a multilayer structure, phosphites and phenolic antioxidants are useful for the purpose of thermal stability.

The flame-retardant polycarbonate resin composition according to the present invention is prepared by weighing the above resin additives, if necessary, in addition to the essential components, such as a tumbler, a V-type blender, a Banbury mixer, a kneading roll, and an extruder. It can be manufactured by mixing with a conventionally known mixer, kneader or the like. When producing the flame-retardant polycarbonate resin composition, the mixing method of each component, the order of mixing is not particularly limited, but the most preferable method is to mix all the components in advance using a evening tumbler, a V-type blender, or the like. And a method of uniformly melting and mixing with an extruder. But,
Depending on the form of the components, two or three of these components
It is also possible to adopt a method in which the seed is made into a premixed mixture, and the remaining components are mixed with the mixture.

The flame-retardant polycarbonate resin composition thus obtained is subjected to a conventionally known molding method such as an extrusion molding method, an injection molding method, a compression molding method, a blow molding method or a gas injection molding method. It can be easily formed into a molded product such as a target product or part. The sheet manufactured by the extrusion molding method can be further formed into a target molded article by a vacuum molding method. The obtained molded product is excellent in mechanical strength, light resistance, heat resistance, surface appearance, flame retardancy, non-dropping property, thermal stability when melting,
Since it has excellent properties such as light-shielding properties and light reflectance, it can be suitably used for a wide range of applications such as lighting devices, liquid crystal backlights, and electrical components.

[0033]

EXAMPLES The present invention will be specifically described below based on examples, but the present invention is not limited to the following examples unless it exceeds the gist.

The components used in the following Examples and Comparative Examples are as follows. (A) Component polycarbonate resin: bisphenol A
(Hereinafter abbreviated as “PC”) having a viscosity average molecular weight of 22,000 (trade name: Iupilon, manufactured by Mitsubishi Engineering-Plastics Corporation). Component (B) titanium oxide: produced by a chlorine method, having an average particle size of 0.28 μm, and surface-treated with an inorganic surface treatment agent, alumina hydrate and silicic acid hydrate, and then an organic surface treatment agent -Type rutile titanium oxide surface-treated with an organohydrogensiloxane from Ishihara Sangyo Co., Ltd., trade name: Taipek PC3
(Hereinafter abbreviated as PC3) was used.

Component (C) phosphorus-based flame retardant: condensed phosphoric acid ester (trade name: ADK STAB FP- manufactured by Asahi Denka Kogyo Co., Ltd.)
500 (hereinafter abbreviated as “FP500”), a phosphate ester, manufactured by Daihachi Chemical Co., Ltd., trade name: TPP (hereinafter, “TP500”).
P ") was used. In addition, what was used by the comparative example is a halogen-type flame retardant, the polycarbonate oligomer of tetrabromobisphenol A (halogen content 59 weight%) made by Mitsubishi Engineering-Plastics Co., Ltd., brand name: Iupilon FR-53 (hereinafter, "FR53")
Abbreviated).

Component (D) Multilayer elastic body: polyalkylalkylate core / polymethyl methacrylate shell copolymer (manufactured by Kureha Chemical Co., Ltd., trade name: EXL2315)
(Hereinafter abbreviated as “T1”). The one used in the comparative example is a multilayered elastic body having a core of butadiene polymer and a shell of methyl methacrylate (manufactured by Kureha Chemical Co., Ltd., trade name: EXL2603 (hereinafter abbreviated as “T2”)). (E) Fibril-forming polytetrafluoroethylene of component: polytetrafluoroethylene manufactured by Daikin Chemical Industries, trade name: Polyflon F-201 (hereinafter referred to as “PTF”)
E "). (F) Component organophosphite compound: bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-diphosphite (manufactured by Asahi Denka Co., Ltd.)
Trade name: Adegastab PEP-36 (hereinafter abbreviated as PEP) was used.

The molded articles obtained in the following Examples and Comparative Examples were prepared according to the methods described below.
Evaluation tests such as flame retardancy, optical properties (hue, light reflectance, total light transmittance), heat resistance, and silver generation were performed. (a) Izod impact test: A notched test piece having a thickness of 3.2 mm was measured in accordance with ASTM D-256. The unit is Kg · cm / cm. (b) Combustion test: For a test piece having a thickness of 0.8 mm, UL
A 94 standard vertical combustion test was performed. (c) Hue: 90 mm x 60 mm manufactured by injection molding
The L value, the a value, and the b value of a square plate of 2 mm were measured by a color difference meter (model: SE-2000) manufactured by Nippon Denshoku Industries Co., Ltd.

(D) Light reflectivity: The above-mentioned square flat plate was measured with a spectrophotometer manufactured by Hitachi, Ltd. (with an integrating sphere, model: U
-3400), the light reflectance at a wavelength of 550 nm was measured. The unit is%. (e) Total light transmittance: The total light transmittance of the rectangular flat plate was measured using a color difference meter (model: SE-2000) manufactured by Nippon Denshoku Industries Co., Ltd. The unit is%. (f) Heat resistance: heat-treated in an oven at 100 ° C. for 500 hours, and then a color difference meter (model: SE-200, manufactured by Nippon Denshoku Industries Co., Ltd.)
According to 0), ΔE due to the heat treatment was measured. (g) Observation of Silver Generation: The surface of the above rectangular plate was visually observed to determine whether or not silver was generated.

[Examples 1 to 4, Comparative Examples 1 to 4] The above components (A) to (F) were weighed at the ratios (parts by weight) shown in Table 1 and mixed with a mixer. The resulting mixture was kneaded and extruded into pellets at a barrel temperature of 270 ° C. using a 30 mmφ twin screw extruder (manufactured by Nippon Steel Works, model: TEX30). 12 pellets obtained
After drying at a temperature of 0 ° C. for 5 hours, an injection molding machine (manufactured by Nippon Steel Works, model: J-50ED) is used, and a cylinder temperature of 280 ° C. and a mold temperature of 70 ° C. are used, and ASTM-D25 is used.
6 Izod impact test specimen with 3.2 mm thickness, UL
127 × 12.7 × 0.8mm combustion test specimen of 94 standard,
Further, a square flat plate of 90 mm × 60 mm × 2 mm was formed.

The test specimens obtained in each example were evaluated according to the above-described evaluation methods, such as Izod impact strength, flame retardancy, optical properties (hue, light reflectance, total light transmittance), heat resistance, and silver generation. Was done. The results of the evaluation test
It is shown in Table 1.

[0041]

[Table 1]

From Table 1, the following becomes clear. (1) The flame-retardant polycarbonate resin composition according to the present invention is excellent in heat stability at the time of melting, and excellent in flame retardancy and non-dripping property. (2) A molded article obtained from the flame-retardant polycarbonate resin composition according to the present invention is a molded article having excellent impact resistance. (3) Molded articles obtained from the flame-retardant polycarbonate resin composition according to the present invention are excellent in optical properties such as light-shielding properties and light reflectance. (4) On the other hand, in Comparative Example 1 in which a halogen-based flame retardant was added instead of the component (C), silver was generated and the surface appearance was poor. (5) Comparative Example 3 containing no component (D) is significantly inferior in impact resistance, and Comparative Example 2 in which a multilayer elastic body different from the component (D) is blended is inferior in heat resistance. (6) Further, Comparative Example 4 containing no component (E) has flame retardancy,
Poor non-dripping property.

[0043]

The flame-retardant polycarbonate resin composition of the present invention has the following particularly advantageous effects, and its industrial utility value is extremely large. 1. The flame-retardant polycarbonate resin composition according to the present invention is excellent in thermal stability at the time of melting, and excellent in flame retardancy and non-dripping property. 2. The molded article obtained from the flame-retardant polycarbonate resin composition according to the present invention has excellent mechanical strength, light resistance and heat resistance, and also has excellent surface appearance. 3. Molded articles obtained from the flame-retardant polycarbonate resin composition according to the present invention are excellent in optical properties such as light-shielding properties and light reflectance, and therefore, the flame-retardant polycarbonate resin composition is used for lighting devices, liquid crystal backlights, It can be suitably used as a material for manufacturing electric parts and the like.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C08L 51/06 C08L 51/06 (72) Inventor Kazuhiko Ishii 5-6-1 Higashi-Yawata, Hiratsuka-shi, Kanagawa Mitsui Engineering Plastics 4J002 BD153 BG042 BG052 BN122 CG011 CG021 CG031 DE136 EW047 EW088 FB096 FD016 FD038 FD137 FD203 GP00 GQ00

Claims (3)

[Claims] 1. To 100 parts by weight of a polycarbonate resin (A), 0.1 to 50 parts by weight of titanium oxide (B), 0.5 to 40 parts by weight of a phosphorus-based flame retardant (C), and a glass transition point (T
g) a multilayer elastic body (D) having an inner core of a rubbery polymer composed of a crosslinked alkyl (meth) acrylate having a temperature of 0 ° C. or lower and an outermost layer of the alkyl (meth) acrylate; 10 parts by weight, and 0.01 to 1 part by weight of a fibril-forming polytetrafluoroethylene (E), each of which is blended, and a flame-retardant polycarbonate resin composition. 2. The flame-retardant polycarbonate resin composition according to claim 1, wherein the phosphorus-based flame retardant (D) is represented by the following general formula [I] or general formula [II]. Embedded image Embedded image 3. A composition comprising 0.005 to 1.0 part by weight of an organophosphite compound represented by the following general formula [III] per 100 parts by weight of a polycarbonate resin (A). The flame-retardant polycarbonate resin composition according to claim 1 or 2. Embedded image