JP2019143084A - Flame-retardant polycarbonate resin composition and electronic device body containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel polycarbonate resin composition for providing a molded product of a polycarbonate resin composition having both excellent flame retardancy, weather resistance and good appearance. In a flame-retardant polycarbonate resin composition, the content of the flame retardant (B) is 0.001 to 40% by mass, and the content of polytetrafluoroethylene (C) is 0.1 to 1.0% by mass. , A flame-retardant polycarbonate resin composition having a content of the metal salt (D) of 0.01 to 5.0% by mass and a content of the ultraviolet absorber (E) of 0.1 to 3% by mass. The thickest polytetrafluoroethylene (C) fibril present in any one field of 127 μm × 95 μm, in which the fracture surface obtained by freezing and breaking the resin composition in the direction perpendicular to the flow direction was observed with a scanning electron microscope. The present invention relates to a flame-retardant polycarbonate resin composition, wherein the diameter of the portion is 2 μm or less. [Selection diagram] None

Description

  The present invention relates to a flame retardant polycarbonate resin composition and an electronic device casing including the same.

  Polycarbonate resin compositions are widely used in fields such as electricity, electronics, ITE, machinery, automobiles, and building materials because they are excellent in transparency, flame retardancy, heat resistance, mechanical strength, and the like. In recent years, higher flame retardancy has been demanded in these fields. For example, flame retardancy conforming to UL94 test (flammability test of plastic materials for equipment parts) established by Underwriters Laboratories. In the evaluation, high flame retardance that matches V-0 and V-1 is required.

  In order for the polycarbonate resin composition to exhibit such high flame retardancy, it is necessary that the resin does not drop (drip) during combustion. As means for suppressing dripping of the resin during combustion, a fluororesin such as polytetrafluoroethylene (PTFE) is blended with the polycarbonate resin composition. However, when a fluororesin such as polytetrafluoroethylene is blended with the polycarbonate resin composition, the fluororesin aggregates and the fluororesin particles float on the surface of the molded article of the polycarbonate resin composition. .

  As a method for solving such a problem, for example, Patent Document 1 discloses a technique using a polycarbonate resin prepared by suspension polymerization by blending a flame retardant and polytetrafluoroethylene. However, even with this method, polytetrafluoroethylene aggregates in the polycarbonate resin composition, and the polytetrafluoroethylene particles are raised on the surface of the molded article of the polycarbonate resin composition to form a streak-like line. The problem of deterioration in appearance, such as variations in hue, has not been sufficiently solved. In extremely thin-walled injection-molded products stipulated in the UL-94 standard, PTFE is further fibrillated by strong shear during injection molding, and within the narrow field of view, the diameter of the thickest part of the fibrils is 2 μm or less. However, the surface appearance of the molded product cannot be sufficiently improved.

  On the other hand, in recent years, molded products of polycarbonate resin compositions used for electronic equipment installed outdoors, represented by next-generation wattmeters such as smart meters, have excellent flame resistance and long-term use. High weatherability that can be withstood and better appearance (good appearance) are required. If the appearance can be improved, there are many advantages of reducing the number of processes, such as eliminating the need for coating and surface coating, and thus there is an increasing demand for improving the appearance. However, conventionally, the technique disclosed in Patent Document 1 has a problem that the excellent flame retardancy, weather resistance, and good appearance required for a polycarbonate resin composition cannot be satisfied in a well-balanced manner.

JP 2010-106097 A

  An object of this invention is to provide the novel flame-retardant polycarbonate resin composition which gives the molded article which consists of a flame-retardant polycarbonate resin composition which was compatible with the outstanding flame retardance, a weather resistance, and the favorable external appearance.

  The inventors of the present invention have made extensive studies on the production method in order to solve the above-mentioned problems. As a result, the fracture surface is obtained by freeze-breaking a resin composition containing a specific additive in a specific ratio in a polycarbonate resin in a direction perpendicular to the flow direction. Molded using a polycarbonate resin composition in which the average value of the diameter of the thickest part of the fibrils of polytetrafluoroethylene (C) present in one arbitrary field of 127 μm × 95 μm observed with a scanning electron microscope is 2 μm or less As a result, excellent flame retardancy and weather resistance are maintained, and deterioration of the appearance that cannot be avoided with conventional polycarbonate resin compositions containing polytetrafluoroethylene (the fluororesin appears on the surface of the molded product). Finding that line-like lines are formed and variations in hue are effectively suppressed, and the present invention is completed. It was.

That is, the present invention comprises (A) a polycarbonate resin, (B) a flame retardant, (C) polytetrafluoroethylene, (D) a metal salt, and (E) an ultraviolet absorber, and a flame retardant polycarbonate resin composition. Among them, the flame retardant (B) content is 0.001 to 40% by mass, the polytetrafluoroethylene (C) content is 0.1 to 1.0% by mass, and the metal salt (D) content is 0. A flame retardant polycarbonate resin composition having a content of .01 to 5.0% by mass and an ultraviolet absorber (E) of 0.1 to 3% by mass,
The thickest part of the fibrils of polytetrafluoroethylene (C) present in an arbitrary field of view of 127 μm × 95 μm, in which the fracture surface obtained by freezing and breaking the resin composition in a direction perpendicular to the flow direction was observed with a scanning electron microscope This invention relates to a flame retardant polycarbonate resin composition characterized by having a diameter of 2 μm or less.

  The flame retardant (B) is preferably at least one selected from the group consisting of a silicone flame retardant, a halogen flame retardant, and a phosphate ester flame retardant.

  Furthermore, it is preferable to contain at least one thermoplastic resin (F) selected from the group consisting of styrene-acrylonitrile copolymer, polymethacrylstyrene, polyester, polyester elastomer, polyamide, and ethylene vinyl acetate polymer.

  It is preferable that the content of the thermoplastic resin (F) is 0.005 to 5% by mass with respect to 100 parts by mass of the main component.

  It is preferable that the number of foreign matters of 50 μm or more present in a molded product of 80 mm × 52 mm × 2 mm obtained by injection molding the flame retardant polycarbonate resin composition is 10 or less.

  The average particle diameter of the polytetrafluoroethylene (C) is preferably 200 μm or less.

  The metal salt (D) is preferably an aromatic sulfur compound metal salt or a perfluoroalkanesulfonic acid metal salt.

  It is preferable that the ultraviolet absorber (E) is a benzotriazole ultraviolet absorber and / or a triazine ultraviolet absorber.

  The thermoplastic resin (F) preferably has an average particle size of 5 μm or less.

  In addition, the present invention relates to a resin molded product obtained by molding the flame retardant polycarbonate resin composition, and is preferably an electronic device casing including the resin molded product.

  In the flame-retardant polycarbonate resin composition of the present invention, polytetrafluoroethylene present in an arbitrary field of view of 127 μm × 95 μm obtained by observing with a scanning electron microscope a fracture surface obtained by freezing and breaking the resin composition in a direction perpendicular to the flow direction. Since the fibril diameter of fluoroethylene (C) is 2 μm or less, when it is molded using the polycarbonate resin composition, excellent flame retardancy and weather resistance are exhibited, and a conventional polycarbonate containing polytetrafluoroethylene Deterioration of the appearance that could not be avoided with the resin composition can be effectively suppressed. As a result, if the flame retardancy is the same, the blending amount of polytetrafluoroethylene (C) can be reduced, and weather resistance and appearance can be improved.

  The present invention comprises (A) a polycarbonate resin, (B) a flame retardant, (C) polytetrafluoroethylene, (D) a metal salt, and (E) an ultraviolet absorber. In the flame retardant polycarbonate resin composition, The flame retardant (B) content is 0.001 to 40% by mass, the polytetrafluoroethylene (C) content is 0.1 to 1.0% by mass, and the metal salt (D) content is 0.01. A flame retardant polycarbonate resin composition having a content of ˜5.0 mass% and an ultraviolet absorber (E) of 0.1 to 3 mass%, wherein the resin composition is oriented in a direction perpendicular to the flow direction. The diameter of the thickest part of the fibrils of polytetrafluoroethylene (C) present in an arbitrary field of view of 127 μm × 95 μm, in which the frozen fracture surface is observed with a scanning electron microscope, is 2 μm or less. Fire retardant polycar About sulphonate resin composition.

  The direction perpendicular to the flow direction of the resin composition refers to a direction perpendicular to the flow direction of the resin in the resin pellet. For example, in order to prevent the dispersion state of polytetrafluoroethylene (C) from changing, the pellets are cooled to a very low temperature with liquid nitrogen or the like, and the freezing fracture surface is obtained by brittle fracture of the polycarbonate polycarbonate resin. The dispersion form of fibrillated polytetrafluoroethylene (C) is observed with a scanning electron microscope. Without cooling, the polycarbonate will ductile breakage, covering the polytetrafluoroethylene and observing the fibrils. The visual field to be observed is a relatively wide range of 127 μm × 95 μm in order to confirm the entire state. The number of visual fields to be observed is not particularly limited. For example, it is preferable to observe fracture surfaces of three or more pellets. By observing the three pellets, if there are no polytetrafluoroethylene fibrils with a diameter of 2 μm or more at the thickest part, almost no aggregation of polytetrafluoroethylene is observed throughout and high flame retardancy is exhibited. Will do.

  When polytetrafluoroethylene is dispersed with a nonuniform thickness, the diameter of the thickest part (maximum width in the short axis direction) is used. The diameter of the thickest part of the fibril is 2 μm or less, preferably 1 μm or less. When the diameter of the thickest part exceeds 2 μm, the appearance is deteriorated, for example, a streak line is formed or the hue of the surface is varied. If the diameter is 2 μm or less in the pellet state, PTFE is further fibrillated and dispersed well by the strong shear during injection molding in the extremely thin injection molded product specified in UL-94 standard.

  The number of white foreign substances present in a molded product of 80 mm × 52 mm × 2 mm obtained by injection molding of the flame retardant polycarbonate resin composition of the present invention is preferably 10 or less, and more preferably 5 or less. When 11 or more are present, the surface becomes rough and the appearance tends to deteriorate. Here, the white foreign matter is obtained by observing the injection molded product visually and with an optical microscope, and counting foreign matters having a size of 50 μm or more present in the entire molded product.

  The production method of the polycarbonate resin composition of the present invention is not particularly limited. For example, a step of premixing polycarbonate (A) and polytetrafluoroethylene (C) to obtain a premix, and the obtained premix, Production method including polycarbonate (A), flame retardant (B), metal salt (D) and ultraviolet absorber (E) to obtain a melt-kneaded product, polycarbonate (A), flame retardant (B ), Polytetrafluoroethylene (C), metal salt (D) and ultraviolet absorber (E) are premixed to obtain a premixture, and the premixture obtained is melt-kneaded with polycarbonate (A). Thus, it can be produced by a production method including a step of obtaining a melt-kneaded product. With these methods, polytetrafluoroethylene can be favorably dispersed in the polycarbonate, and the fibril diameter can be reduced.

<Preliminary mixing process>
Premixing refers to mixing a polycarbonate (A) and polytetrafluoroethylene (C) before melt-kneading to produce a master batch. If necessary, the flame retardant (B), metal salt (D) and ultraviolet absorber (E) can also be premixed together. The mixing method is not particularly limited, and a method of mixing an aqueous dispersion of a solid state polycarbonate (A) and polytetrafluoroethylene (C), and a mixture of polycarbonate (A) and polytetrafluoroethylene (C) in a solid state And dry blend. Especially, the method of mixing the aqueous dispersion of a polycarbonate (A) of a solid state and polytetrafluoroethylene (C) is preferable at the point from which uniform dispersibility is acquired. The mixing means is not particularly limited, but it is preferable to mix while stirring, and a general mixer (for example, Nauter mixer, Henschel mixer, butterfly mixer, etc.), homogenizer, blender, etc. can be used. Moreover, when preparing the mixed dispersion of these resin particles, you may adjust pH using an acid or a base.

  The mixing amount of polytetrafluoroethylene (C) in the premixing step is not particularly limited, but is preferably 0.1 to 33 parts by mass with respect to 100 parts by mass of the polycarbonate (A) used in the premixing step. -25 mass parts is more preferable, and 3-20 mass parts is further more preferable. When the flame retardant (B), the metal salt (D), and the ultraviolet absorber (E) are also premixed, the amount of the flame retardant (B) mixed is not particularly limited, but the mass of the polycarbonate (A) used in the premixing step is 100 mass. 0.005-100 mass parts is preferable with respect to part, and 0.01-80 mass parts is more preferable. The mixing amount of the metal salt (D) is preferably 0.01 to 5.0 with respect to 100 parts by mass of the polycarbonate (A). The mixing amount of the ultraviolet absorber (E) is preferably 0.1 to 3.0 with respect to 100 parts by mass of the polycarbonate (A).

  In the preliminary mixing step, the thermoplastic resin (F) may be mixed together with the polycarbonate (A) and the polytetrafluoroethylene (C), and the polytetrafluoroethylene (C) and the thermoplastic resin (F) are mixed in advance. Later, it may be premixed with the polycarbonate (A). Polytetrafluoroethylene (C) and the thermoplastic resin (F) are preferably used as an aqueous dispersion. If necessary, the flame retardant (B), metal salt (D) and ultraviolet absorber (E) can also be premixed together.

  The kneading amount of the thermoplastic resin (F) in the preliminary mixing is not particularly limited, but is preferably 0.1 to 33% by mass, and preferably 0.2 to 25% with respect to 100 parts by mass of the polycarbonate (A) used in the preliminary mixing step. The mass% is more preferable, and 3 to 20 mass% is more preferable.

  It is preferable to provide a drying step after the preliminary mixing. Examples of the drying means include various drying means such as hot air drying, vacuum drying, steam drying, spin drying, and suction drying.

<Melting and kneading process>
In melt kneading, the premix obtained in the premixing step is melt kneaded with the polycarbonate (A), the flame retardant (B), the metal salt (D), and the ultraviolet absorber (E). In addition, when a flame retardant (B), a metal salt (D), and an ultraviolet absorber (E) are mixed in the preliminary mixing step, it is not necessary to knead the flame retardant in the melt-kneading step. The kneading method is not particularly limited, and examples thereof include an extruder (melt kneader, melt kneader), a batch kneader, and the like. The extruder may be a single screw or a multi-screw. In the case of a multi-screw, a twin-screw extruder such as a meshing type co-rotating twin-screw extruder or a multi-screw extruder having two or more axes can be preferably used. . Usually, a normal meshing type co-rotating twin screw extruder or the like is preferably used. Although kneading | mixing temperature is not specifically limited, 220 to 340 degreeC is preferable and 240 to 320 degreeC is more preferable. When the temperature exceeds 340 ° C., the resin / additive is decomposed and the additive is aggregated, which tends to cause a defective appearance of the molded product.

  Although the addition amount of the polycarbonate (A) newly mix | blended by a melt-kneading process is not specifically limited, 250-10000 mass parts is preferable with respect to 100 mass parts of premixes, and 500-5000 mass parts is more preferable. When it exceeds 10,000 parts by mass, the productivity is inferior, and when it is less than 250 parts by mass, uniform flame retardancy tends to be not obtained.

  The amount of the flame retardant (B) added in the melt-kneading step is not particularly limited, but is 0.01 to 25 parts by mass with respect to a total of 100 parts by mass of the polycarbonate contained in the preliminary kneaded product and the newly added polycarbonate. Preferably, 0.01-10 mass parts is more preferable, and 0.01-5 mass parts is further more preferable. If the amount is less than 0.01 parts by mass, it becomes difficult to obtain stable flame retardancy. If the amount exceeds 25 parts by mass, the polycarbonate may be decomposed, which may cause problems in production.

<Blending ingredients>
The polycarbonate (A) used in the present invention is a polymer obtained by a phosgene method in which various dihydroxydiaryl compounds and phosgene are reacted, or a transesterification method in which a dihydroxydiaryl compound and a carbonate such as diphenyl carbonate are reacted. is there. A typical example is a polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (commonly called 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 ' Dihydroxydiaryl sulfoxides such as dimethyldiphenyl sulfoxide, dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone Rusuruhon, and the like can be mentioned.

  These may be used alone or in combination of two or more. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4′-dihydroxydiphenyl, and the like may be used in combination.

  Furthermore, a trivalent or higher valent phenol compound as shown below may be mixed and used together with the dihydroxyaryl compound. 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 (A) is not particularly limited, but is preferably from 10,000 to 100,000, more preferably from 15,000 to 35,000, in terms of moldability and strength. Moreover, when manufacturing this polycarbonate, a molecular weight modifier, a catalyst, etc. can be used as needed. The viscosity average molecular weight (Mv) of the polycarbonate is 0.5% by mass in methylene chloride solution, the specific viscosity (ηsp) is measured at a temperature of 20 ° C. using a Cannon-Fenske type viscosity tube, and the intrinsic viscosity is converted by concentration conversion. [Η] is obtained and calculated from the following SCHNELL equation.
[Η] = 1.23 × 10 ⁻⁴ × Mv ^0.83

  The proportion of the polycarbonate contained in the flame retardant polycarbonate resin composition of the present invention is preferably 50 to 99.5% by mass from the viewpoint of imparting excellent flame retardancy and excellent appearance to the polycarbonate resin composition. 70-99.5 mass% is more preferable, and 85-99.5 mass% is further more preferable.

  The form of the polycarbonate (A) is not particularly limited, and examples thereof include pellets, flakes, and beads. Among these, a flaky material is preferable and a porous flaky material is more preferable in that uniform dispersibility can be obtained. The bulk density of the polycarbonate is not particularly limited, but is preferably 0.1 to 0.9, and more preferably 0.1 to 0.7. Here, a bulk density means the value measured based on the solid apparent bulk density of JISK7370. The size of the polycarbonate is not particularly limited, but is preferably 5 mm or less.

  Although the flame retardant (B) used by this invention is not specifically limited, For example, a silicone type flame retardant, a halogenated flame retardant, a phosphate ester type flame retardant etc. are mentioned. From the viewpoint of exhibiting excellent flame retardancy and excellent appearance, a silicone-based flame retardant is particularly preferable. As the silicone flame retardant, for example, a silicone compound described in JP-A-11-217494 is preferably a silicone compound having a branched structure in the main chain and having an aromatic group in the organic functional group contained therein.

  More specifically, as shown in the following general formula, the main chain has a branched structure and contains an aromatic group as an organic functional group, that is, a general T unit and / or Q unit as a branch unit. Those having are preferred.

  These preferably contain 20 mol% or more of the total siloxane units. If it is less than 20 mol%, the heat resistance of the silicone compound is lowered and the flame retardancy effect is lowered, and the viscosity of the silicone compound itself is too low, which may adversely affect the kneadability and moldability with polycarbonate. . More preferably, it is 30 mol% or more and 95 mol% or less. When it is 30 mol% or more, the heat resistance of the silicone compound is further increased, and the flame retardancy of the polycarbonate resin containing it is greatly improved. However, if it exceeds 95 mol%, the degree of freedom of the main chain of the silicone decreases, and condensation of aromatic groups during combustion may be difficult to occur, and it may be difficult to express significant flame retardancy.

  Moreover, it is preferable that an aromatic group is 20 mol% or more among the organic functional groups which a silicone compound has. If it is less than this range, condensation of aromatic groups hardly occurs at the time of combustion, and the flame retardant effect may be reduced. More preferably, it is 40-95 mol%. If it is 40 mol% or more, the aromatic group at the time of combustion can be condensed more efficiently, and at the same time, the dispersibility of the silicone compound in the polycarbonate resin (A) is greatly improved, and an extremely good flame retardant effect is exhibited. it can. If it exceeds 95 mol%, these condensations may be difficult to occur due to steric hindrance between aromatic groups, and it may be difficult to exhibit a remarkable flame-retardant effect.

  The aromatic group is phenyl, biphenyl, naphthalene, or a derivative thereof, but a phenyl group is preferable from the viewpoint of safety of the silicone compound. Of the organic functional groups in the silicone compound attached to the main chain or branched side chain, the organic group other than the aromatic group is preferably a methyl group, and the terminal group is a methyl group, phenyl group, hydroxyl group, alkoxy group. Among the groups (particularly methoxy group), one selected from the above or a mixture of 2 to 4 thereof is preferable. In the case of these terminal groups, since the reactivity is low, gelation (crosslinking) of the silicone compound hardly occurs when the polycarbonate resin (A) and the silicone compound are kneaded, so that the silicone compound is uniform in the polycarbonate resin (A). As a result, it can have a better flame retardant effect, and the moldability is also improved. Particularly preferred is a methyl group. In this case, since the reactivity is extremely low, the dispersibility becomes extremely good, and the flame retardancy can be further improved.

  The weight average molecular weight of the silicone compound is preferably 5,000 to 500,000. If it is less than 5,000, the heat resistance of the silicone compound itself is lowered and the flame retardancy effect is lowered. Further, the melt viscosity is too low and the silicone compound oozes out on the surface of the molded body of the polycarbonate resin (A) during molding. When the viscosity exceeds 500,000, the melt viscosity increases and the uniform dispersion in the polycarbonate resin (A) is impaired, and the flame retardancy effect and moldability may be reduced. More preferably, it is 10,000 to 270000. In this range, since the melt viscosity of the silicone compound is optimal, the silicone compound can be dispersed very uniformly in the polycarbonate resin (A) and does not exude excessively to the surface. Can be achieved.

  The ratio of the flame retardant (B) contained in the flame retardant polycarbonate resin composition of the present invention is 0.001 to 40 from the viewpoint of imparting excellent flame retardancy and excellent appearance to the polycarbonate resin composition. Mass% is preferred. In the case of a halogen flame retardant, 1 to 40% by mass is preferable, 5 to 35% by mass is more preferable, and 8 to 25% by mass is more preferable. In the case of a phosphate ester flame retardant, 3 to 25% by mass is preferable.

  The polytetrafluoroethylene (C) used in the present invention is not particularly limited, and a polytetrafluoroethylene homopolymer may be used. However, it contains a copolymer and a terpolymer that do not impair the performance of the polytetrafluoroethylene. You may use what is. The polytetrafluoroethylene may be a copolymer.

  The form of polytetrafluoroethylene (C) is not particularly limited, but particles are preferred. The average particle size is preferably 200 μm or less, and more preferably 100 μm or less. If it is 200 micrometers or less, the outstanding flame retardance and the outstanding external appearance can be provided. Here, the average particle diameter means that 50 ml of methylene chloride is added to 1 g of the composite resin particles, and the solution obtained by leaving it to stand at 23 ° C. for 3 hours is stirred with a stirrer for 20 minutes without dissolving. The major axis and minor axis of the remaining 100 PTFE particles are measured, and (major axis + minor axis) / 2 is defined as the particle diameter, which is the average value of the particle diameters of 100 PTFE particles.

  PTFE-containing additives that can be used to add polytetrafluoroethylene particles to the polycarbonate resin composition are commercially available (for example, A3800 manufactured by Mitsubishi Rayon Co., SN3307 manufactured by Shine Polymer Co., etc.) ), The additive does not have an average particle size of 200 μm or less as measured by the above measurement method.

  Polytetrafluoroethylene (C) is used as an aqueous dispersion in terms of relatively uniform dispersibility, that is, less generation of polytetrafluoroethylene aggregates and excellent uniformity in dispersibility and reproducibility. It is preferable. Although the solid content rate of the polytetrafluoroethylene (C) in an aqueous dispersion is not specifically limited, 20-65 mass% is preferable and 20-70 mass% is more preferable.

  The ratio of polytetrafluoroethylene (C) contained in the flame-retardant polycarbonate resin composition of the present invention is 0.1% from the viewpoint of imparting excellent flame retardancy and excellent appearance to the polycarbonate resin composition. Although it is -1 mass%, 0.1-0.5 mass% is more preferable.

  The flame-retardant polycarbonate resin composition of the present invention preferably contains a thermoplastic resin (F) from the viewpoint of exhibiting a function of dispersing polytetrafluoroethylene with high uniformity in the resin composition.

  The thermoplastic resin (F) is not particularly limited, but it is preferable to use a resin having affinity with the polycarbonate resin and the fluororesin. Examples thereof include styrene-acrylonitrile copolymer (SAN), polymethacryl styrene polymer (MS), polyester, polyester elastomer, polyamide, ethylene vinyl acetate polymer (EVA), and the like. Of these, styrene-acrylonitrile copolymer (SAN) is particularly preferable. As the thermoplastic resin, one kind may be used alone, or two or more kinds may be used in combination.

  The form of the thermoplastic resin (F) is not particularly limited, but it is preferably used in the form of particles. The average particle size is preferably 5 μm or less, more preferably 0.01 to 2 μm. If it is 5 micrometers or less, a fluororesin can be suitably disperse | distributed with respect to a polycarbonate resin composition, and the outstanding flame retardance and the outstanding external appearance can be provided.

  The thermoplastic resin (F) is preferably used as an aqueous dispersion in that polytetrafluoroethylene aggregate generation in the flame retardant resin composition is reduced and uniform dispersibility is obtained. Although the solid content concentration of a thermoplastic resin (F) is not specifically limited, 20-70 mass% is preferable. Moreover, as for the compounding quantity of a thermoplastic resin (F), 0.03-5 mass parts is preferable with respect to 100 mass parts of polycarbonate (A).

  The ratio of the thermoplastic resin (F) contained in the flame-retardant polycarbonate resin composition of the present invention is 0.005 to 5 from the viewpoint of imparting excellent flame retardancy and excellent appearance to the polycarbonate resin composition. % By mass is preferable, and 0.01 to 1% by mass is more preferable.

  As the metal salt (D) contained in the flame retardant polycarbonate resin composition of the present invention, a known organic metal salt blended in the polycarbonate resin composition can be used. The metal salt (D) is not particularly limited, and examples thereof include aromatic sulfur compound metal salts and perfluoroalkanesulfonic acid metal salts. Examples of the metal of the metal salt (D) include alkali metals and alkaline earth metals. As a compounding quantity of metal salt (D), 0.01-5 mass parts is preferable with respect to 100 mass parts of polycarbonate resin, and 0.03-3 mass parts is more preferable.

As the ultraviolet absorber (E) used in the present invention, one or more ultraviolet absorbers selected from benzotriazole ultraviolet absorbers and triazine ultraviolet absorbers are preferable. Specifically, as the triazine ultraviolet absorber used in the present invention, 2-
(4,6-diphenyl-1,3,5-triazin-2-yl) -5-hexyloxyphenol, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5 Methyloxyphenol, 2- (4,6-diphenyl-1,3,5-triazin-2-yl)-
5-ethyloxyphenol, 2- (4,6-diphenyl-1,3,5-triazine-2
-Yl) -5-propyloxyphenol, and 2- (4,6-diphenyl-1,3,
5-Triazin-2-yl) -5-butyloxyphenol, bis {2- [4- (4,6
-Diphenyl-1,3,5-triazin-2-yl) -3-hydroxyphenoxy] ethyl} dodecandioate and the like, for example, TINUVIN 15 manufactured by BASF
77, Adeka Stab LA-1000 manufactured by Adeka Corporation, etc. are commercially available.

  Examples of the benzotriazole-based ultraviolet absorber (E) used in the present invention include 2- (2-hydroxy-5-methylphenyl) benzotriazole and 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole. 2- (2-hydroxy-3,5-dicumylphenyl) phenylbenzotriazole, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2,2′- Methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2- (2-hydroxy-3,5-di-tert-butylphenyl) ) Benzotriazole, 2- (2-hydroxy-3,5-di-tert-butylphenyl) -5-chlorobenzotriazo 2- (2-hydroxy-3,5-di-tert-amylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy-5-tert) -Butylphenyl) benzotriazole, 2- (2-hydroxy-4-octoxyphenyl) benzotriazole, 2,2'-methylenebis (4-cumyl-6-benzotriazolephenyl), 2,2'-p-phenylenebis (1,3-benzoxazin-4-one) and the like are exemplified.

Of these, 2- (2-hydroxy-5-t-octylphenyl) benzotriazole and the like are particularly suitable, for example, TINUVIN 329 (TINUVIN manufactured by BASF).
Are registered trademarks), Seasorb 709 manufactured by Sipro Kasei Co., Ltd., and Chemisorb 79 manufactured by Chemipro Kasei Co., Ltd. are commercially available.

The blending amount of the ultraviolet absorber (E) is preferably 0.1 to 3 parts by weight per 100 parts by weight of the polycarbonate resin (A). If the blending amount is less than 0.1 parts by weight, the weather resistance is inferior, and if it exceeds 3 parts by weight, high flame retardancy may not be exhibited or initial coloring occurs, which is not preferable. A more preferred range is 0.1 to 0.6 parts by weight.

  In addition to the components (A) to (F) described above, the flame-retardant polycarbonate resin composition of the present invention can contain various components that are generally blended in flame-retardant polycarbonate resin compositions. Such components include, for example, various resins, further flame retardants, antioxidants, fluorescent brighteners, colorants, fillers, mold release agents, antistatic agents, rubber (elastomers), softening materials, spreading Agents (liquid paraffin, epoxidized soybean oil, etc.) and further organometallic salts.

  As various kinds of resins, known resins to be blended in the polycarbonate resin composition can be blended. Examples of the various resins include polystyrene, high impact polystyrene, ABS, AES, AAS, AS, acrylic resin, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyarylate, polysulfone, and polyphenylene sulfide resin. These resins may be used alone or in combination of two or more.

  As antioxidant, the well-known antioxidant mix | blended with a polycarbonate resin composition can be used. Examples of the antioxidant include phosphorus antioxidants and phenolic antioxidants. Of these, hindered phenolic antioxidants are preferably used. For example, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], thiodiethylene-bis [ Examples include 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate. As a compounding quantity of antioxidant, 0.005-1 mass part is mentioned with respect to 100 mass parts of polycarbonate resin, for example.

  As the colorant, a known colorant blended in the polycarbonate resin composition can be used. The colorant is not particularly limited, and dyes and pigments (titanium dioxide, carbon black, etc.) can be used. As a compounding quantity of a coloring agent, 0.0001-10 mass parts is mentioned with respect to 100 mass parts of polycarbonate resins, for example.

  As a filler, the well-known filler mix | blended with a polycarbonate resin composition can be used. The filler is not particularly limited, and examples thereof include glass fiber, carbon fiber, silica, talc, and mica. As a compounding quantity of a filler, 3-120 mass parts is preferable with respect to 100 mass parts of polycarbonate resin.

  As the rubber (elastomer), a known filler blended in the polycarbonate resin composition can be used. The rubber (elastomer) is not particularly limited, and examples thereof include isobutylene / isoprene rubber, styrene / butadiene, acrylic elastomer, polyester elastomer, and core-shell type elastomer. As a compounding quantity of rubber | gum (elastomer), 0.05-20 mass parts is preferable with respect to 100 mass parts of polycarbonate resin.

  The flame-retardant polycarbonate resin composition of the present invention is a grade when a vertical combustion test (V test) of UL standard 94 (flammability test of plastic materials for equipment parts) is performed with a test piece thickness of 1.5 mm. Is preferably V-0.

  The present invention also relates to a resin molded article obtained by molding the flame retardant polycarbonate resin composition. Since the flame-retardant polycarbonate resin composition of the present invention is used, the molded product has few foreign matters and is excellent in surface appearance as well as flame retardancy and weather resistance.

  In the present invention, the electronic device casing means, for example, a housing including a housing, casing, cover, internal chassis or the like for an electric / electronic device. In particular, a thin case, a housing and the like of a portable electronic device are preferable examples. More specifically, it means an alternative to a metal product used for a laptop computer, a portable information terminal such as a smartphone, a thin camera casing such as a video camera, a digital camera, or a smart meter, a housing, a casing, or an internal chassis.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on mass.

(Production Example 1) Production of Preliminary Mixture A Polytetrafluoroethylene particle aqueous dispersion (primary particle size 0.15 to 0.25 μm: Polyflon D210-C manufactured by Daikin Industries, Ltd.) and styrene-acrylonitrile copolymer particles The aqueous dispersion (primary particle size 0.05-1 μm: K-1158 manufactured by Japan A & L) was mixed at a mass ratio (solid content ratio) of 50:50 (= PTEF particles: SAN particles). The resulting mixed solution was neutralized with an acid to obtain a neutralized mixed solution. Next, a neutralized mixed liquid (solid content 0.46 parts by mass) was added to 4 parts by mass of powder of polycarbonate resin particles (primary particle diameter 1 mm). Next, the mixture was heated to 80 ° C., stirred for 0.5 hours using a super mixer, and then dried to produce Premix A. The mass ratio of the PC resin particles, the PTFE particles, and the SAN particles in the premix A is 89.0: 6.5: 6.5. Moreover, as a result of measuring the obtained preliminary mixture A by the above-mentioned method, it had an average particle diameter of 5 mm or less.

<Measurement of average particle diameter of PTFE particles>
To 1 g of the premix A, 50 ml of methylene chloride was added and left at 23 ° C. for 3 hours. Next, the obtained solution was stirred with a stirrer for 20 minutes, and the major axis and minor axis were measured for 100 PTFE particles remaining undissolved, and (major axis + minor axis) / 2 was defined as the particle diameter. The average value of the particle sizes of the PTFE particles was taken as the average particle size of the PTFE particles. As a result, the average particle size in the preliminary mixture A was 70 μm. The minimum value of the minor axis was 9 μm, and the maximum value of the major axis was 264 μm.

(Production Example 2) Production of Preliminary Mixture B Polytetrafluoroethylene particle aqueous dispersion (primary particle size 0.15-0.25 μm: Polyflon D210-C manufactured by Daikin Industries, Ltd.) and styrene-acrylonitrile copolymer particles Except that the aqueous dispersion (primary particle size 0.05-1 μm: K-1158 manufactured by Japan A & L Co.) was mixed at a mass ratio (solid content ratio) of 65:35 (= PTEF particles: SAN particles), Premix B was produced in the same manner as in Production Example 1. The mass ratio of the PC resin particles, the PTFE particles, and the SAN particles in the premix B is 89.7: 6.7: 3.6. Moreover, the obtained preliminary mixture B was measured by the above-mentioned method, and had an average particle diameter of 5 mm or less.

(Production Example 3) Production of Preliminary Mixture C Polytetrafluoroethylene particle aqueous dispersion (primary particle size 0.15 to 0.25 μm: Polyflon D210-C manufactured by Daikin Industries, Ltd.) and styrene-acrylonitrile copolymer particles Except that the aqueous dispersion (primary particle size 0.05-1 μm: K-1158 manufactured by Japan A & L Co.) was mixed at a mass ratio (solid content ratio) of 35:65 (= PTEF particles: SAN particles), In the same manner as in Production Example 1, Premix C was produced. The mass ratio of the PC resin particles, the PTFE particles, and the SAN particles in the premix C is 82.3: 6.2: 11.5. Moreover, the obtained preliminary mixture C had an average particle diameter of 5 mm or less as a result of measuring by the above-mentioned method.

(Examples 1-7 and Comparative Examples 1-3)
Each component was put into a tumbler so as to have the composition described in Table 1 and Table 2, and dry-mixed for 10 minutes. Next, it knead | mixed at the melting temperature of 280 degreeC using the twin-screw extruder (TEX30 (alpha) made from Nippon Steel Works), and obtained the pellet of each polycarbonate resin composition. The obtained pellets were injection-molded with an injection molding machine (ROBOSHOT S-2000i manufactured by FANAC), and the obtained molded product was subjected to evaluation described later. Details of each component described in Table 1 and Table 2 are as follows. In addition, the preliminary mixtures A to C are manufactured in the above-described manufacturing examples 1 to 3. In all Examples and Comparative Examples, a small amount of an antioxidant (phosphorus-based and phenol-based), an elastomer, and a release agent are added in common.

(Each component)
(Component A)
PC: Polycarbonate resin (SD polycarbonate 200-20 manufactured by Sumika Polycarbonate Co., Ltd .: Aromatic polycarbonate resin, bulk density 0.7 g / ml)
(B component)
Flame retardant: Silicone flame retardant (copolymer of diorganodichlorosilane, monoorganotrichlorosilane, and tetrachlorosilane, M / D / T / Q = 14/16/70/0 (moles of main chain structure) Ratio), the ratio of phenyl groups in all organic functional groups is 32 mol%, the end groups are methyl groups, and the weight average molecular weight is about 65000)
(C component)
Preliminary mixture A (according to Production Example 1)
Preliminary mixture B (according to production example 2)
Preliminary mixture C (according to Production Example 3)
(D component)
PTSNa: sodium paratoluenesulfonate (sodium paratoluenesulfonate manufactured by Chori Co., Ltd.)
C4: potassium perfluorobutane sulfonate (BAYWET C4 manufactured by LANXESS)
B-55: Barium sulfate (barium sulfate B-55 manufactured by Sakai Chemical Industry Co., Ltd.)
(E component)
UVA: Tinuvin 1577; Benzotriazine UV absorber (Triazine UV absorber manufactured by Ciba Specialty Chemicals)
A3800: PTFE / MS (polymethacrylstyrene) manufactured by Mitsubishi Rayon = 50/50 particles SN3307: PTFE / SAN manufactured by Shine Polymer Co., Ltd. = styrene / acrylonitrile copolymer = 50/50 particles

<Fiber diameter (maximum width in short axis direction)>
The obtained pellets were notched and then frozen with liquid nitrogen and ruptured in a direction perpendicular to the flow direction. The fracture surface is observed with a scanning electron microscope, and the diameter of the thickest part (maximum width in the short axis direction) of the fibril of polytetrafluoroethylene (C) existing in any one field of 127 μm × 95 μm exceeds 2 μm. Counted the number. A total of three pellets were measured, and those having two or more fibrils of 2 μm or more were evaluated as x, and those having one or less were evaluated as ◯. These results are shown in Tables 1 and 2. In the fibril exposed on the fracture surface of the pellet, the maximum width in the minor axis direction of the fibril cross section was regarded as the fibril diameter.

<Flame retardance evaluation>
In accordance with UL standard 94 (flammability test of plastic materials for equipment parts), a vertical combustion test (V test) was performed with a test piece thickness of 1.5 mm, and the grade was evaluated. The results are shown in Tables 1 and 2. V-0 was judged as good and V-1 or less as bad.

<Appearance evaluation 1: Number of foreign objects>
The pellets obtained in Examples 1 to 7 and Comparative Examples 1 to 3 were dried at 125 ° C. for 4 hours, and then an injection molding machine (ROBOSHOT S-2000i manufactured by FANAC) was used to form a test piece at a temperature of 300. A test piece (80 mm × 52 mm × 2 mm flat plate) was produced under the conditions of ℃, injection pressure 100 MPa, mold temperature 100 ° C. Next, the visible region of each test piece was observed visually and with an optical microscope, and the number of foreign matters having a diameter of 50 μm or more was counted. Evaluation was made according to the following criteria. The results are shown in Tables 1 and 2.
◯: The number of foreign matters is 0 to 5 and there is almost no surface roughness. Δ: The number of foreign matters is 6 to 10 and the surface is somewhat rough. ×: The number of foreign matters is more than 10. Large surface roughness

<Evaluation of weather resistance>
The obtained various pellets were dried at 125 ° C. for 4 hours, and then subjected to a weather resistance evaluation test piece (50 × 90 × 2.P) at a set temperature of 300 ° C. using an injection molding machine (ROBOSHOT S-2000i manufactured by FANAC). 0 mm). The obtained test piece was attached to a weather meter (Sunshine Super Long Life Weather Meter WEL-SUN-HCH-B type manufactured by Suga Test Instruments Co., Ltd.), irradiance 100 W / m2, black panel temperature 89 ° C., no rain Under these conditions, the yellowness index (YI) after 600 hours of irradiation was determined. For weather resistance, the degree of yellowing (ΔYI) after irradiation relative to before irradiation was calculated and evaluated. The ΔYI after irradiation for 600 hours was rated as less than 35 and marked as 35 or more.

  According to the flame-retardant polycarbonate resin composition of the present invention, a molded product molded from the obtained resin composition has both excellent flame retardancy, weather resistance and good appearance, and can be used in outdoor applications. Since there are many merits such as no need for painting and surface coating on the body, it can be suitably applied to applications that require both appearance improvement and flame retardancy and weather resistance, and has extremely high industrial utility value.

Claims (10)

(A) A polycarbonate resin, (B) a flame retardant, (C) polytetrafluoroethylene, (D) a metal salt, and (E) an ultraviolet absorber. In the flame retardant polycarbonate resin composition, a flame retardant (B ) Content of 0.001 to 40% by mass, polytetrafluoroethylene (C) content of 0.1 to 1.0% by mass, and metal salt (D) content of 0.01 to 5.0%. A flame retardant polycarbonate resin composition having a mass% and a content of the ultraviolet absorber (E) of 0.1 to 3.0 mass%,
The thickest part of the fibrils of polytetrafluoroethylene (C) present in an arbitrary field of view of 127 μm × 95 μm, in which the fracture surface obtained by freezing and breaking the resin composition in a direction perpendicular to the flow direction was observed with a scanning electron microscope The flame retardant polycarbonate resin composition is characterized by having a diameter of 2 μm or less.   The flame retardant polycarbonate resin composition according to claim 1, wherein the flame retardant (B) is at least one selected from the group consisting of a silicone flame retardant, a halogen flame retardant, and a phosphate ester flame retardant. object.   Furthermore, it contains at least one (F) thermoplastic resin selected from the group consisting of styrene-acrylonitrile copolymer, polymethacrylstyrene, polyester, polyester elastomer, polyamide, and ethylene vinyl acetate polymer. Or the flame-retardant polycarbonate resin composition of 2.   The flame-retardant polycarbonate resin composition according to claim 3, wherein a content of the thermoplastic resin (F) is 0.005 to 5% by mass with respect to 100 parts by mass of the main component.   The number of foreign matters of 50 μm or more present in a molded product of 80 mm × 52 mm × 2 mm obtained by injection molding of the flame retardant polycarbonate resin composition is 10 or less. The flame-retardant polycarbonate resin composition as described.   The flame-retardant polycarbonate resin composition according to any one of claims 1 to 5, wherein the polytetrafluoroethylene (C) has an average particle size of 200 µm or less.   2. The flame retardant polycarbonate resin composition according to claim 1, wherein the metal salt (D) is an aromatic sulfur compound metal salt or a perfluoroalkanesulfonic acid metal salt.   2. The flame retardant polycarbonate resin composition according to claim 1, wherein the ultraviolet absorber (E) is a benzotriazole ultraviolet absorber and / or a triazine ultraviolet absorber.   The flame-retardant polycarbonate resin composition according to claim 3, wherein the thermoplastic resin (F) has an average particle size of 5 μm or less.   The electronic device housing | casing containing the resin molded product obtained by shape | molding the flame-retardant polycarbonate resin composition of any one of Claims 1-9.