JP2005263911A - Flame-retardant polycarbonate resin composition excellent in light reflectivity and light-reflecting plate made thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-retardant polycarbonate resin composition which has excellent light reflectivity and high flame retardance, is excellent in environmental friendliness because it contains no halogen flame retardant comprising a chlorine or bromine compound or the like or contains no phosphorus flame retardant, has excellent surface appearance and mechanical strength, and can be used as, especially, a material for a reflecting plate used in e.g., a liquid crystal backlight. <P>SOLUTION: The flame-retardant polycarbonate resin composition excellent in light reflectivity comprises 100 pts.wt. polycarbonate resin (A), 0.01 to 2 pts.wt. polytetrafluoroethylene (B), 5 to 25 pts.wt. titanium oxide (C), 0.01 to 3 pts.wt. organohydrogensiloxane, 0.01 to 2 pts. wt. silicone compound (E) in which the main chain has a branched structure and contains organic functional groups being aromatic groups or being aromatic groups and hydrocarbon groups (other than aromatic groups), and 0.005 to 2 pts.wt. organometal salt (F). A light-reflecting plate made of the same is also provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flame retardant, impact resistance, workability, surface appearance in which a specific polytetrafluoroethylene-containing mixed powder, a specific titanium oxide, a polyorganohydrogensiloxane, a specific silicone compound, and an organometallic salt compound are blended. In addition, the present invention relates to a flame retardant polycarbonate resin composition excellent in light reflectivity in consideration of environmental influences, and a light reflecting plate formed from the composition. The resin composition according to the present invention is excellent in light reflectivity, and also has excellent flame retardancy, impact resistance, workability, and surface appearance during molding. It can be suitably used for a plate.

  Polycarbonate resin is a thermoplastic resin excellent in impact resistance, heat resistance, and the like, and is widely used in fields such as electricity, electronics, machinery, automobiles, and building materials. Among these, in order to satisfy safety requirements in the fields of electricity, electronics, OA, etc., in addition to the above-described excellent performance possessed by the polycarbonate resin, a material having high flame retardancy is required.

  Conventionally, flame retardants such as organic bromine compounds and phosphorus compounds have been used. Recently, various flame retardant methods using silicone flame retardants that are more environmentally friendly have been proposed and adopted. It is being done.

However, in order to satisfy the high flame retardancy such as V-0 based on the US Underwriters Laboratories (UL) standard 94, the flame retardant only with the silicone flame retardant is of course insufficient and dripping. In order to prevent this, it has been proposed and practiced to incorporate a polytetrafluoroethylene resin.
Japanese Patent Laid-Open No. 60-23442 JP 60-260647 A JP-A-61-57645

  However, when polytetrafluoroethylene resin is blended with polycarbonate resin and granulated, the polytetrafluoroethylene resin itself aggregates easily during processing, resulting in poor feedability to the extruder barrel and impact due to poor dispersion of the resin. There was a problem that the strength decreased and the surface appearance deteriorated. These problems, particularly in the case of a light-reflective flame-retardant polycarbonate resin composition, lead to a reduction in impact strength of the light-reflecting plate obtained by molding the surface and deterioration of the surface appearance due to the occurrence of silver streaks. Was desired.

  The present inventors do not sacrifice the impact resistance, which is a feature of polycarbonate resin, they are extremely excellent in workability and surface appearance during granulation processing, and light reflection that fully considers the impact on the environment The present inventors have found a flame retardant polycarbonate resin composition having excellent properties and have reached the present invention.

  That is, according to the present invention, polytetrafluoroethylene-containing mixed powder (B) 0.01-2 parts by weight, titanium oxide (C) 5-25 parts by weight, polyorganohydrogensiloxane (100 parts by weight of polycarbonate resin (A) D) 0.01 to 3 parts by weight, a silicone compound in which the main chain has a branched structure and the organic functional group contained is an aromatic group, or is composed of an aromatic group and a hydrocarbon group (excluding an aromatic group) (E) A flame-retardant polycarbonate resin composition excellent in light reflectivity, comprising 0.01 to 2 parts by weight and an organometallic salt (F) 0.005 to 2 parts by weight, and light comprising the same A reflector or a light reflector for a liquid crystal backlight is provided.

  The flame-retardant polycarbonate resin composition excellent in light reflectivity of the present invention does not contain a halogen-based flame retardant or a phosphorus-based flame retardant composed of chlorine, bromine compounds, etc., and thus has excellent performance in terms of environment. In addition to having high flame retardancy and light reflectivity, it has excellent surface appearance and mechanical strength, and can be suitably used as a material for reflectors for liquid crystal backlight applications.

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

  Examples of the dihydroxydiaryl compound include bisphenol 4-, 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, 2,2-bis ( Bis (hydroxyaryl) alkanes such as 4-hydroxy-3,5-dichlorophenyl) propane, 1,1- (4-hydroxyphenyl) cyclopentane, bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3 Dihydroxy diaryl ethers such as 3,3'-dimethyldiphenyl ether, dihydroxy diaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3 ' Dihydroxy diaryl sulfoxides such as dimethyldiphenyl sulfoxide, dihydroxy diary such as 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone Sulfone, and the like.

  These are used singly or as a mixture of two or more. However, it is preferable not to be substituted with a halogen from the viewpoint of preventing discharge of a gas containing halogen, which is a concern during combustion, into the environment. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4'-dihydroxydiphenyl, and the like may be mixed and used.

  Furthermore, the above dihydroxyaryl compound and a trivalent or higher phenol compound as shown below may be used in combination. Trihydric or higher phenols 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) -benzol, 1,1,1-tri- (4-hydroxyphenyl) -ethane and 2,2-bis- [4 4- (4,4'-dihydroxydiphenyl) -cyclohexyl] -propane and the like.

  The viscosity average molecular weight of the polycarbonate resin (A) is usually 10,000 to 100,000, preferably 15,000 to 35,000. In producing such an aromatic polycarbonate resin, a molecular weight regulator, a catalyst, and the like can be used as necessary.

  The polytetrafluoroethylene-containing mixed powder (B) used in the present invention is composed of polytetrafluoroethylene particles having a particle diameter of 10 μm or less and an organic polymer, and polytetrafluoroethylene has a particle diameter of 10 μm. It is necessary that the aggregate does not become an aggregate. Furthermore, from the viewpoint of dispersibility when blended with a thermoplastic resin, in a dispersion obtained by mixing an aqueous dispersion of polytetrafluoroethylene particles having a particle diameter of 0.05 to 1.0 μm and an aqueous dispersion of organic polymer particles Thus, it is necessary to use a polymer obtained by polymerizing a vinyl monomer and then pulverizing it by coagulation or spray drying. The polytetrafluoroethylene-containing mixed powder (B) according to the present invention, which is used to obtain the polytetrafluoroethylene-containing mixed powder (B), is an emulsion polymerization using a fluorine-containing surfactant. It is obtained by polymerizing tetrafluoroethylene monomer.

  Fluorine-containing olefins such as hexafluoropropylene, chlorotrifluoroethylene, fluoroalkylethylene, and perfluoroalkyl vinyl ether as copolymerization components in the emulsion polymerization of polytetrafluoroethylene particles as long as the properties of polytetrafluoroethylene are not impaired. Fluorine-containing alkyl (meth) acrylates such as perfluoroalkyl (meth) acrylate can be used. The content of the copolymer component is preferably 10% by weight or less with respect to tetrafluoroethylene.

  Commercially available raw materials for the polytetrafluoroethylene particle dispersion include: Fullon AD-1 and AD-936 manufactured by Asahi Glass Fluoropolymer, Polyflon D-1 and D-2 manufactured by Daikin Industries, Ltd., and Teflon manufactured by Mitsui Dupont Fluorochemical Co., Ltd. 30J etc. can be mentioned as a representative example.

  The organic polymer particle aqueous dispersion used for obtaining the polytetrafluoroethylene-containing mixed powder (B) according to the present invention can be obtained by polymerizing a vinyl monomer by a known method such as emulsion polymerization. it can.

  The vinyl monomer used to obtain the organic polymer particle aqueous dispersion, and the polytetrafluoroethylene particle aqueous dispersion having a particle diameter of 0.05 to 1.0 μm and the organic polymer particle aqueous dispersion were mixed. Although it does not restrict | limit especially as a vinyl monomer polymerized in a dispersion liquid, Affinity with polycarbonate resin (A) is high from a dispersible viewpoint at the time of mix | blending with polycarbonate resin (A). It is preferable.

  Specific examples of these vinyl monomers include styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, t-butylstyrene, o-ethylstyrene, p-chlorostyrene, o-chlorostyrene, 2, Aromatic vinyl monomers such as 4-dichlorostyrene, p-methoxystyrene, o-methoxystyrene, 2,4-dimethylstyrene; methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, Butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tridecyl acrylate, tridecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, cyclohexyl acrylate, cyclohexane methacrylate (Meth) acrylic acid ester monomers such as xylyl; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; α, β-unsaturated carboxylic acids such as maleic anhydride; N-phenylmaleimide, N-methylmaleimide, Maleimide monomers such as N-cyclohexylmaleimide; Epoxy group-containing monomers such as glycidyl methacrylate; Vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether; Vinyl carboxylates such as vinyl acetate and vinyl butyrate Body; α-olefin monomers such as ethylene, propylene, and isobutylene; and diene monomers such as butadiene, isoprene, and dimethylbutadiene. These monomers can be used alone or in admixture of two or more.

  Among these monomers, one or more selected from the group consisting of aromatic vinyl monomers and vinyl cyanide monomers is preferable from the viewpoint of affinity with the polycarbonate resin (A). Mention may be made of monomers containing 30% by weight or more of monomers. Particularly preferred is a monomer containing 30% by weight or more of one or more monomers selected from the group consisting of styrene and acrylonitrile.

  The content ratio of polytetrafluoroethylene in the mixed powder containing polytetrafluoroethylene used in the present invention is preferably 0.1% by weight to 90% by weight. If it is less than 0.1% by weight, the flame retardancy improving effect becomes insufficient, and if it exceeds 90% by weight, the surface appearance may be adversely affected.

  The polytetrafluoroethylene-containing mixed powder (B) used in the present invention is dried after the aqueous dispersion is poured into hot water in which a metal salt such as calcium chloride or magnesium sulfate is dissolved, salted out and solidified. Or it can be pulverized by spray drying.

While ordinary polytetrafluoroethylene fine powder becomes an aggregate of 100 μm or more in the process of recovering as a powder from the state of a particle dispersion, it is difficult to uniformly disperse it in a thermoplastic resin. The polytetrafluoroethylene-containing mixed powder (B) used in the present invention is extremely excellent in dispersibility in the polycarbonate resin (A) because the polytetrafluoroethylene alone does not form a domain having a particle diameter exceeding 10 μm. ing. As a result, in the polycarbonate resin composition of the present invention, polytetrafluoroethylene is efficiently made into fine fibers in the polycarbonate, and the flame retardancy is excellent, and the surface properties and impact characteristics are also excellent.

  The compounding quantity of polytetrafluoroethylene containing mixed powder (B) is 0.01-2 weight part per 100 weight part of polycarbonate resin (A). If it is less than 0.01 part by weight, the effect of preventing dripping is inferior, so that it is difficult to obtain flame retardancy. On the other hand, if it exceeds 2 parts by weight, impact resistance, surface appearance and the like are lowered, which is not preferable. Preferably it is 0.1-1.5 weight part, More preferably, it is 0.6-1.0 weight part.

  Titanium oxide (C) used in the present invention may be produced by either a chlorine method or a sulfuric acid method, and the crystal form may be either a rutile type or an anatase type. Further, the particle size of titanium oxide is preferably about 0.1 to 0.5 μm. In particular, titanium oxide surface-treated with polyene phosphorous oxide is preferably used.

  The proportion of titanium oxide treated with phosphorylated polyene is preferably at least 0.02% by weight of phosphorus, more preferably 0.04 to 0.1% by weight of phosphorus with respect to titanium oxide. Treated titanium oxide is preferred.

  Polyene is a higher fatty acid having a plurality of unsaturated bonds in its molecular structure, and has a minimum of 10 carbon atoms, preferably about 18, and a maximum of 28. More specific examples of polyenes include linolenic acid and linoleic acid.

  Further, it may be in the form of a mixture with a fatty acid having only one unsaturated bond in the molecule, such as oleic acid or a saturated fatty acid, such as stearic acid, and further, phosphorous of various derivatives of fatty acids. An oxide or the like may be included. More specific examples of these derivatives include alkyl fatty acid esters and fatty acid amides.

There are various methods for phosphorylation of polyene, but the most common means is a method using a Friedel-Crafts catalyst, and the detailed procedure is disclosed in the following publicly known documents and the like. .

E. Jungermann and J.M. J. et al. McBridge
J. et al. Org. Chem. , 26, 4182 (1961)

E. Jungermann, J.A. J. et al. McBridge, R.M. Clutter and
A. Masis
J. et al. Org. Chem. , 27,606 (1962), etc.

Other effective polyenes include diphosphonic acid or diphosphonic acid esters of paramentane.
General formula (1)

General formula (2)

  In the general formulas (1) and (2), R1, R2, R3 and R4 each represent a hydrogen atom or a C1-C10 alkyl group.

  The compounding quantity of a titanium oxide (C) is 5-25 weight part per 100 weight part of polycarbonate resin (A). If the blending amount is less than 5 parts by weight, the light reflectivity is inferior, and if it exceeds 25 parts by weight, the appearance and flame retardancy are deteriorated. More preferably, it is 9 to 16 parts by weight.

  Examples of the polyorganohydrogensiloxane (D) used in the present invention include methylhydrogenpolysiloxane, methylhydrogenpolycyclosiloxane, and the like, particularly selected from the structural units represented by the following general formulas (3) to (5). The compounds are preferred.

General formula (3)
(R) a (H) b Si (4-ab)
Wherein R is a monovalent hydrocarbon group free from aliphatic unsaturation,
a is 1.00-2.10, b is 0.1-1.0,
(A + b) is 2.00 to 2.67. )

  General formula (4)

  General formula (5)

  When other polyorganohydrogensiloxanes are used, the molecular weight and yellowness of the polycarbonate resin are reduced during melt kneading at high temperatures, and a large amount of gas is generated during molding and silver streaks are generated in the molded product. Sometimes.

  The titanium oxide (C) and the polyorganohydrogensiloxane (D) can be directly blended into the polycarbonate resin (A) as it is. Moreover, before blending with the polycarbonate resin (A), the titanium oxide (C) may be once surface-treated with the polyorganohydrogensiloxane (D) and blended with the polycarbonate resin (A).

  As the surface treatment method, either a wet method or a dry method may be used. Examples of the wet method include a method in which titanium oxide (C) is added to a mixed solution of a polyorganohydrogensiloxane (D) and a low-boiling solvent, and this is stirred and then subjected to a solvent removal treatment. Then, you may heat-process further at the temperature of 120-200 degreeC. Examples of the dry method include a method of mixing and stirring polyorganohydrogensiloxane (D) and titanium oxide (C) with a mixing apparatus such as a super mixer, a Henschel mixer, and a V-type tumbler. At this time, heat treatment may be performed at a temperature of 120 to 200 ° C.

  The compounding quantity of polyorganohydrogensiloxane (D) is 0.01-3 weight part per 100 weight part of polycarbonate resin (A). If it is less than 0.01 part by weight, the inactivation action of titanium oxide is reduced, so that the composition is inferior in light reflectivity. If it exceeds 3 parts by weight, gas generation derived from the siloxane increases and silver streak is remarkable. become. The amount is preferably 0.05 to 1 part by weight, more preferably 0.1 to 0.5 part by weight.

The silicone compound (E) having a branched structure of the main chain and an organic functional group consisting of an aromatic group, or consisting of an aromatic group and a hydrocarbon group (excluding an aromatic group) is represented by the following general formula (6). As shown in
General formula (6)

Here, R1, R2, and R3 represent main chain organic functional groups, and X represents a terminal functional group.

That is, it has a T unit (RSiO _1.5 ) and / or a Q unit (SiO _2.0 ) as a branch unit. These preferably contains more than 20 mol% of the total siloxane units _{(R 3~0 SiO 2~0.5).} (R represents an organic functional group.) Further, the silicone compound (E) preferably contains 20 mol% or more of aromatic groups among the organic functional groups contained.

  The aromatic group contained is phenyl, biphenyl, naphthalene or a derivative thereof, but a phenyl group can be preferably used.

  Of the organic functional groups in the silicone compound (E) attached to the main chain or branched side chain, the organic group other than the aromatic group is preferably a hydrocarbon group having 4 or less carbon atoms, and preferably a methyl group. Can be used. Further, the terminal group is preferably one kind selected from methyl group, phenyl group and hydroxyl group, or a mixture of these two kinds to three kinds.

  The average molecular weight (weight average) of the silicone compound (E) is preferably 3,000 to 500,000, more preferably 5,000 to 270000.

  The compounding quantity of a silicone compound (E) is 0.01-2 weight part per 100 weight part of polycarbonate resin (A). If the blending amount is outside the range, the flame retardant effect is insufficient in any case, which is not preferable. More preferably, it is 0.05-1.0 weight part.

  Examples of the organic metal salt (F) used in the present invention include a metal salt of an aromatic sulfonic acid and a metal salt of a perfluoroalkane sulfonic acid, preferably 4-methyl-N- (4-methyl Phenyl) sulfonyl-benzenesulfonamide potassium salt, potassium diphenylsulfone-3-sulfonate, potassium diphenylsulfone-3-3′-disulfonate, sodium paratoluenesulfonate, potassium perfluorobutanesulfonate, and the like can be used.

  The compounding amount of the organic metal salt (F) is 0.005 to 2 parts by weight per 100 parts by weight of the polycarbonate resin (A). A blending amount of less than 0.005 parts by weight is not preferable because the flame retardancy decreases. On the other hand, if it exceeds 2 parts by weight, problems such as failure to obtain mechanical properties and flame retardancy and deterioration of the surface appearance are undesirable. More preferably, it is 0.2 to 1 part by weight.

  By blending the above components (C), (D), (E), and (F) with the polycarbonate resin (A), a certain degree of flame retardancy is shown, but it is not sufficient. In the present invention, not only the components (C), (D), (E), (F) but also the component (B), that is, a specific polytetrafluoroethylene-containing mixed powder is blended with the polycarbonate resin (A). This is a fire retardant that gives a synergistic effect, is self-extinguishing without dripping, is excellent in impact resistance, workability during granulation, and surface appearance, and has sufficient consideration for its impact on the environment. A functional polycarbonate resin composition can be provided.

  In mixing the components (A), (B), (C), (D), (E), and (F) defined in the present invention, there is no limitation on the form and order. For example, a method of adding powdered (B), (C), (D), (E), (F) to a polycarbonate resin (A) in an organic solvent solution, powder or pellets, a molten polycarbonate resin ( For example, a method of adding (B), (C), (D), (E), (F) in a powder state to A). In addition, a method of mixing all the components at once with a tumbler, a ribbon blender, a high-speed mixer, or the like, or a method of once mixing arbitrary components with these mixers and then blending the remaining components. Furthermore, a master batch in which the polycarbonate resin (A) and the polytetrafluoroethylene-containing mixed powder are mixed is prepared in advance, and then the master batch and the polycarbonate resins (A) and (C), (D), (E ), (F) and the like can also be mixed in a desired composition. These mixtures are easily melt-kneaded and pelletized using a normal single-screw or twin-screw extruder.

  The flame retardant polycarbonate resin composition of the present invention contains a known additive such as a phenol-based or phosphorus-based heat stabilizer [2,6-di-t-butyl-4-methylphenol, 2- (1-methylcyclohexyl). ) -4,6-dimethylphenol, 4,4'-thiobis- (6-tert-butyl-3-methylphenol), 2,2-methylenebis- (4-ethyl-6-tert-methylphenol), n- Octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, tris (2,4-di-t-butylphenyl) phosphite, 4,4'-biphenylenediphosphinic acid tetrakis- (2 , 4-di-t-butylphenyl), etc.], UV absorber [pt-butylphenyl salicylate, 2,2'-dihydroxy-4-methoxybenzophenone 2- (2′-hydroxy-4′-n-octoxyphenyl) benzotriazole etc.], lubricant [paraffin wax, n-butyl stearate, synthetic beeswax, natural beeswax, glycerin monoester, montanic acid wax, polyethylene wax, Pentaerythritol tetrastearate, etc.], filler [calcium carbonate, clay, silica, glass fiber, glass sphere, glass flake, carbon fiber, talc, mica, various whiskers, etc.], fluidity improver [monophosphorine such as triphenyl phosphate, etc.] Examples thereof include acid esters and oligomeric condensed phosphoric ester. ], Spreading agents [epoxidized soybean oil, liquid paraffin, etc.], and other thermoplastic resins such as polyamide, polyethylene terephthalate, polybutylene terephthalate, amorphous polyester, polyphenylene ether, polymethyl methacrylate, and various resistances An impact modifier (for example, rubber reinforced resin obtained by graft polymerization of a compound such as methacrylic acid ester, styrene or acrylonitrile on rubber such as polybutadiene, polyacrylic acid ester or ethylene / propylene rubber) is required. It can be added depending on.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. “Parts” are based on weight unless otherwise specified.

Details of the materials used in the examples are as follows.
(A) Polycarbonate resin:
Caliber 200-20 (Molecular weight: 18600), manufactured by Sumitomo Dow

(B) Polytetrafluoroethylene-containing mixed powder:
B-1: Mitsubishi Rayon Co., Ltd., Metabrene A3800
(Polytetrafluoroethylene content: 50%)
b-1: NEOFRON FA500, manufactured by Daikin Industries, Ltd.
(Normal polytetrafluoroethylene resin)

(C) Titanium oxide:
Titanium oxide surface-treated with polyene phosphorus oxide (polyene was phosphorylated using linolenic acid). (The phosphorus concentration in titanium oxide was 0.06%) The inorganic surface treatment agent for titanium oxide used alumina.

(D) Polyorganohydrogensiloxane:
KF99 (Viscosity: 20 cSt, 25 ° C.) manufactured by Shin-Etsu Chemical Co., Ltd.

(E) Silicone compound:
The silicone compound was produced according to a general production method. That is, a silicone compound partially condensed by dissolving an appropriate amount of diorganodichlorosilane, monoorganotrichlorosilane and tetrachlorosilane, or a partially hydrolyzed condensate thereof in an organic solvent, adding water and hydrolyzing it. Then, triorganochlorosilane was added and reacted to terminate the polymerization, and then the solvent was separated by distillation or the like. The structural characteristics of the silicone compound synthesized by the above method are as follows:
・ D / T / Q unit ratio of main chain structure: 40/60/0 (molar ratio)
-Ratio of phenyl group in all organic functional groups (*): 60 mol%
-Terminal group: methyl group only-Weight average molecular weight (**): 15,000
*: The phenyl group is first contained in the T unit in the silicone containing the T unit, and the remaining D group is contained in the D unit. When the phenyl group is attached to the D unit, the one attached is preferential, and when the phenyl group remains, two are attached. Except for the terminal group, the organic functional group is a methyl group except for the phenyl group.
**: Weight average molecular weight is two significant digits.

(F) Organometallic salt:
Sodium paratoluenesulfonate

  As a blending method, the above-mentioned various raw materials are collectively put into a tumbler at the blending ratio shown in Table 1, and after dry mixing for 10 minutes, using a 37 mm twin-screw extruder (Kobe Steel KTX37), the melting temperature Melt-kneading was performed at 280 ° C. to obtain a flame-retardant polycarbonate resin composition pellet.

  From the obtained pellets, a test piece for mechanical property evaluation of ASTM specifications and a test piece for evaluation of UL94 flammability (1.) using an injection molding machine (Japan Steel Works J100E-C5) under a melting temperature of 280 ° C. 0 mm thickness).

The evaluation methods are as follows.
1. Combustion quality:
The flammability was evaluated according to the following UL94V vertical combustion test method. The test piece is allowed to stand for 48 hours in a temperature-controlled room with a temperature of 23 ° C. and a humidity of 50%, and is flame retardant according to UL94 test (flammability test for plastic materials for equipment parts) established by Underwriters Laboratories. Was evaluated. UL94V is a method for evaluating flame retardance from the afterflame time and drip properties after indirect flames of a burner for 10 seconds on a test piece of a predetermined size held vertically, and is divided into the following classes: .
V-0 V-1 V-2
10 seconds or less for each sample 30 seconds or less 30 seconds or less Afterflame time 5 samples for 50 seconds or less 250 seconds or less 250 seconds or less Total afterflame time No drip None Yes Attached cotton ignition This is the length of time that the test piece continues to burn in flame after moving away from the ignition source. The ignition of cotton by drip means that the marking cotton, which is about 300 mm below the lower end of the test piece, moves It is determined by whether or not it is ignited by a drip. As a criterion for evaluation, V-0 was set to pass in the 1.0 mm thickness test.

2. Light reflectivity:
A three-stage plate (thickness 3, 2, 1 mm) test piece having a length of 90 mm and a width of 40 mm was prepared. 35SP). A sample having a Y value of 94% or more was regarded as acceptable.

3. Impact resistance:
The notched Izod impact strength was measured according to ASTM D-256, and an impact value of 30 kg · cm / cm or more was regarded as acceptable. Thickness is 3.2 mm.

4). Surface appearance:
A three-stage plate (thickness 3, 2, 1 mm) test piece having a length of 90 mm and a width of 40 mm was prepared, and the surface appearance (silver streak and surface roughness (pinhole generation) state) was visually observed. .
○: No silver streak, no rough skin ×: Silver streak, rough skin

  Table 1 Mixing ratio and evaluation results

  As shown in Examples 1 and 2, for those satisfying the specified value range of the essential component of the present invention and the blending amount of each blended component, flame retardancy, light reflectivity, impact strength, surface appearance (silver streak and It met all performance standards such as the condition of rough skin).

  On the other hand, as shown in Comparative Examples 1 to 3, each of the essential components of the present invention and those not satisfying the specified range of the blending amount of each blending component had drawbacks.

  In Comparative Example 1, since the blending amount of the polytetrafluoroethylene-containing mixed powder of the present invention was less than the lower limit of the specified range, the flame retardancy did not satisfy the standard.

  In Comparative Example 2, since the blending amount of the polytetrafluoroethylene-containing mixed powder of the present invention is larger than the upper limit of the specified range, impact strength and surface appearance (both silver streak and rough skin occurrence) are rejected. It became.

In Comparative Example 3, since a normal polytetrafluoroethylene resin was used instead of the polytetrafluoroethylene of the present invention, the impact strength and the surface appearance (rough skin state) were rejected.

Claims (6)

  Polytetrafluoroethylene-containing mixed powder (B) 0.01-2 parts by weight, titanium oxide (C) 5-25 parts by weight, polyorganohydrogensiloxane (D) 0.01-100 parts by weight of polycarbonate resin (A) 3 parts by weight of a silicone compound (E) 0.01 having a branched structure of the main chain and an organic functional group containing an aromatic group or an aromatic group and a hydrocarbon group (excluding an aromatic group) A flame-retardant polycarbonate resin composition excellent in light reflectivity, comprising ~ 2 parts by weight and 0.005 to 2 parts by weight of an organometallic salt (F).   The titanium oxide (C) is surface-treated with a polyene phosphorous oxide, and the degree of surface treatment of the titanium oxide (C) includes at least 0.02% by weight of phosphorus with respect to the titanium oxide. The flame-retardant polycarbonate resin composition excellent in light reflectivity according to claim 1.   The titanium oxide (C) is surface-treated with a polyene phosphorous oxide, and the degree of surface treatment of the titanium oxide (C) includes 0.04 to 0.1% by weight of phosphorus with respect to the titanium oxide. The flame-retardant polycarbonate resin composition having excellent light reflectivity according to claim 1.   The organic metal salt (F) is a metal salt of aromatic sulfonic acid or a metal salt of perfluoroalkanesulfonic acid, and has excellent light reflectivity according to any one of claims 1 to 3. Flame retardant polycarbonate resin composition.   The light reflection board shape | molded using the flame-retardant polycarbonate resin composition excellent in the light reflectivity in any one of Claims 1-4. A light reflecting plate for a liquid crystal backlight formed by using the flame retardant polycarbonate resin composition having excellent light reflectivity according to any one of claims 1 to 4.