JP5164199B2 - Flame retardant polycarbonate resin composition excellent in light shielding property and light reflector comprising the same - Google Patents

Description

  The present invention relates to a flame retardant polycarbonate resin composition having stable light shielding properties regardless of molding processing conditions. Specifically, a flame retardant polycarbonate resin composition excellent in light-shielding properties obtained by blending a polycarbonate resin with titanium oxide, silsesquioxane, an organometallic salt compound and a fiber-forming fluorine-containing polymer, and light reflection comprising the same Regarding the board.

  Polycarbonate resin is a thermoplastic resin excellent in impact resistance, heat resistance, flame retardancy, and the like. In addition, a resin composition comprising titanium oxide, an organometallic salt compound, and a fiber-forming fluorine-containing polymer is a flame-retardant resin material having excellent light reflectivity. It is also used as a reflector material. In recent years, liquid crystal display devices and the like have a tendency to be reduced in size and thickness, and accordingly, a light reflecting plate is also required to be reduced in thickness.

  However, when the thickness of the light reflecting plate is reduced, the amount of light from the light source that passes through the light reflecting plate increases, and sufficient light reflectivity cannot be obtained. Therefore, in order to obtain a desired light reflectivity, conventionally, a large amount of titanium oxide has been added to the polycarbonate resin to devise a light-shielding property so as not to transmit light. Further, attempts have been made to improve the light shielding property by subjecting the added titanium oxide to a surface treatment or further adding an inorganic filler (see Patent Documents 1 to 3).

JP 2004-155985 A JP 2006-176568 A Japanese Patent Laid-Open No. 2006-225452

  The polycarbonate resin added with a large amount of titanium oxide as described above has a problem that the resin is easily burnt at the time of molding because the heat stability is deteriorated even if the light shielding property is improved. As there was plenty of room for improvement. Further, when an inorganic filler is added, there is a problem that the surface appearance and impact resistance of the molded product are lowered, and these improvements have been desired.

  As a result of investigations to solve the above problems, the present inventors have found that a polycarbonate resin is blended with titanium oxide, an organometallic salt compound, a fiber-forming fluorine-containing polymer, and silsesquioxane. The present inventors have found that a polycarbonate resin composition that is highly flame-retardant and has stable light-shielding properties can be obtained regardless of the above conditions, and the present invention has been completed.

  That is, the present invention relates to 5 to 25 parts by weight of titanium oxide (B), 0.1 to 3 parts by weight of silsesquioxane (C), and 0 to the organometallic salt compound (D) 0 per 100 parts by weight of the polycarbonate resin (A). A flame-retardant polycarbonate resin composition having excellent light shielding properties, comprising 0.005 to 2 parts by weight and 0.01 to 2 parts by weight of a fiber-forming fluorine-containing polymer (E), and a light reflecting plate comprising the same Is to provide.

  The flame-retardant polycarbonate resin composition having excellent light-shielding properties of the present invention exhibits stable light-shielding properties regardless of the molding processing conditions, and can be applied to various shapes and processing conditions. It can be suitably used as a light reflecting plate material for LED display boards and the like.

  The polycarbonate resin (A) used in the present invention is obtained by a phosgene method in which various dihydroxy diaryl compounds and phosgene are reacted or a transesterification method obtained by reacting a dihydroxy diaryl 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 types, but are preferably not substituted with halogen from the viewpoint of preventing discharge of the gas containing the halogen into the environment during combustion. 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 a polycarbonate resin, a molecular weight regulator, a catalyst and the like can be used as necessary.

  The titanium oxide (B) used in the present invention may be produced by either the chlorine method or the sulfuric acid method, and the crystal form thereof may be either a rutile type or an anatase type. In addition, titanium oxide having a particle size of about 0.1 to 0.5 μm can be suitably used.

  The compounding quantity of a titanium oxide (B) 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-shielding property is inferior, and if it exceeds 25 parts by weight, the heat stability and flame retardancy deteriorate, which is not preferable. More preferably, it is 9 to 16 parts by weight.

Silsesquioxane (C) used in the present invention is a compound represented by the following general formula (1).
General formula (1)

  In the formula, R represents one or more functional groups selected from an alkyl group having 1 to 12 carbon atoms, a phenyl group that may be substituted with an alkyl group, a vinyl group, and a cycloalkyl group.

  Of these, silsesquioxane in which R is a methyl group is preferably used. Silsesquioxane in which R is a methyl group can be obtained, for example, as MSP-S020 manufactured by Nikko Rica.

  The compounding quantity of silsesquioxane (C) is 0.1-3 weight part per 100 weight part of polycarbonate resin (A). If the blending amount is less than 0.1 parts by weight, the light shielding property and flame retardancy are lowered, and if it exceeds 3 parts by weight, the surface appearance is lowered, which is not preferable. More preferably, it is 1-2 parts by weight.

  Examples of the organic metal salt compound (D) used in the present invention include aromatic sulfonic acid metal salts and perfluoroalkanesulfonic acid metal salts, and 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. Of these, sodium paratoluenesulfonate or potassium perfluorobutanesulfonate is preferably used.

  The compounding amount of the organometallic salt compound (D) is 0.005 to 2 parts by weight per 100 parts by weight of the polycarbonate resin (A). If the blending amount is less than 0.005 parts by weight, the flame retardancy is lowered, which is not preferable. Moreover, when a compounding quantity exceeds 2 weight part, since a mechanical property and a flame retardance fall or a surface external appearance deteriorates, it is unpreferable. More preferably, it is 0.1 to 1 part by weight.

  As the fiber-forming fluorine-containing polymer (E) used in the present invention, those that form a fiber structure (fibril structure) in the polycarbonate resin (A) are preferable, and polytetrafluoroethylene and tetrafluoroethylene-based copolymers are used. Examples thereof include polymers (for example, tetrafluoroethylene / hexafluoropropylene copolymers, etc.), partially fluorinated polymers as shown in US Pat. No. 4,379,910, polycarbonates produced from fluorinated diphenols, and the like. In particular, polytetrafluoroethylene having a molecular weight of 1,000,000 or more and a fibril-forming ability having a secondary particle diameter of 100 μm or more is preferably used. Further, a polytetrafluoroethylene-containing mixed powder composed of polytetrafluoroethylene particles and an organic polymer is also preferably used as the fiber-forming fluorine-containing polymer (E). The polytetrafluoroethylene-containing mixed powder can be obtained, for example, as Metablene A3800 manufactured by Mitsubishi Rayon Co., Ltd.

  The amount of the fiber-forming fluoropolymer (E) is 0.01 to 2 parts by weight per 100 parts by weight of the polycarbonate resin (A). If the blending amount is less than 0.01 parts by weight, the effect of preventing dripping is inferior and the flame retardancy is lowered, which is not preferable. Moreover, since a surface external appearance will deteriorate when a compounding quantity exceeds 2 weight part, it is unpreferable. Preferably it is 0.1-1.5 weight part, More preferably, it is 0.6-1.0 weight part.

  In addition, various heat stabilizers, antioxidants, colorants, fluorescent brighteners, mold release agents, softeners, antistatic agents and other additives, inorganic fillers, impacts, etc., as long as the effects of the present invention are not impaired. You may mix | blend property improvement material and other resin.

  There are no particular limitations on the method of mixing the various compounding components (A), (B), (C), (D) and (E) in the polycarbonate resin composition of the present invention, and known mixers such as tumblers and ribbons are used. Examples thereof include blending with a blender and the like and melt kneading with an extruder. In addition, any order of mixing various blending components (A), (B), (C), (D), and (E), that is, batch mixing and divided mixing of specific blending components can be employed.

  Moreover, there is no restriction | limiting in particular also in the method of shape | molding the polycarbonate resin composition of this invention, A well-known injection molding method, injection / compression molding method, etc. can be used.

  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.

The following were used as raw materials.
(A) Polycarbonate resin Caliber 200-20 manufactured by Sumitomo Dow
(B) Titanium oxide Ishihara Sangyo Taipake PF-740
(C) Silsesquioxane MSP-S020 manufactured by Nikko Rica Corporation
(D) Organometallic salt compound:
Sodium paratoluenesulfonate (Wako Pure Chemical Reagents)
(E) Polytetrafluoroethylene-containing mixed powder:
Metablene A3800 manufactured by Mitsubishi Rayon Co., Ltd. (hereinafter abbreviated as “PTFE mixed powder”)

  The above-mentioned various raw materials are collectively put into a tumbler at the blending ratio shown in Table 2, and after dry mixing for 10 minutes, they are kneaded at a melting temperature of 280 ° C. using a twin screw extruder (KTX37 manufactured by Kobe Steel). Various pellets of the polycarbonate resin composition were obtained.

  Various test pieces were prepared from the obtained pellets using an injection molding machine (J100E-C5 manufactured by Nippon Steel Works), and various data were collected by the following methods.

(Light shielding)
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 transmitted illuminance of a portion having a thickness of 1 mm was measured. As a light source, an xenon light source (ILV) manufactured by Olympus was used, and the test piece was irradiated with light having an illuminance of 30000 lux. A Minolta digital illuminometer T-1H was used for measurement of transmitted illuminance.
(Surface appearance)
Using the test piece prepared in the evaluation of the light shielding property, the surface appearance was visually observed.

(Flame retardance)
The flammability was evaluated according to the following UL94V vertical combustion test method. The test piece is left 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 the 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: .

  The after-flame time shown in Table 1 is the length of time that the specimen keeps flaming combustion after the ignition source is moved away. The ignition of cotton by drip is about 300 mm below the lower end of the specimen. It is determined by whether a certain marking cotton is ignited by a drip from the specimen. The evaluation standard was V-0 or higher in the 1.6 mm thickness test.

  As shown in Examples 1 to 4, those satisfying all the requirements of the present invention were excellent in all performances such as flame retardancy, light reflectivity, and fluidity. On the other hand, as shown in Comparative Examples 1 to 4, those not satisfying the requirements of the present invention had the following drawbacks.

Comparative Example 1 is an example in which the blending amount of silsesquioxane is less than the range defined by the present invention, and the light shielding properties and flame retardancy were insufficient.
Comparative Example 2 is an example in which the blending amount of silsesquioxane is larger than the range defined by the present invention, and the surface appearance was insufficient.
Comparative Example 3 was an example in which the blending amount of titanium oxide was less than the range defined by the present invention, and the light shielding property was insufficient.
Comparative Example 4 is an example in which the compounding amount of titanium oxide is larger than the range defined by the present invention, and the surface appearance and flame retardancy were insufficient.

Claims (6)

5-100 parts by weight of titanium oxide (B), 0.1-3 parts by weight of silsesquioxane (C), 0.005-2 parts by weight of organometallic salt compound (D) per 100 parts by weight of the polycarbonate resin (A) A resin composition comprising 0.01 to 2 parts by weight of a fiber-forming fluorine-containing polymer (E), wherein the organometallic salt compound (D) is an aromatic sulfonic acid metal salt or perfluoroalkanesulfonic acid. A flame retardant polycarbonate resin composition having excellent light shielding properties, which is a metal salt . The flame-retardant polycarbonate resin composition having excellent light shielding properties according to claim 1, wherein the silsesquioxane (C) has a structure represented by the following general formula (1).
General formula (1)

(In the formula, R represents one or more functional groups selected from an alkyl group having 1 to 12 carbon atoms, a phenyl group that may be substituted with an alkyl group, a vinyl group, and a cycloalkyl group.) The flame retardant polycarbonate resin composition having excellent light shielding properties according to claim 1, wherein the silsesquioxane (C) has a structure represented by the following general formula (2).
General formula (2)

  The flame-retardant polycarbonate resin composition having excellent light shielding properties according to claim 1, wherein the fiber-forming fluorine-containing polymer (E) is a polytetrafluoroethylene-containing mixed powder. A light reflecting plate obtained by molding the polycarbonate resin composition according to any one of claims 1 to 4 . The light reflecting plate according to claim 5 , which is used for a liquid crystal frame or a lamp holder.