WO2011065231A1

WO2011065231A1 - Polycarbonate resin composition

Info

Publication number: WO2011065231A1
Application number: PCT/JP2010/070068
Authority: WO
Inventors: 敬直竹内; 誠一前場
Original assignee: 出光興産株式会社
Priority date: 2009-11-27
Filing date: 2010-11-11
Publication date: 2011-06-03
Also published as: KR20120089737A; JP2011111560A; CN102612543A; TW201125923A

Abstract

Disclosed is a polycarbonate resin composition that has excellent thin-walled flame retardance, heat conductivity, mold release characteristics, and impact properties, and that comprises (A) an aromatic polycarbonate resin, every 100 masses of which is combined with (B) 28-90 masses of graphite and (C) 9-20 masses of polytetrafluoroethylene.

Description

Polycarbonate resin composition

The present invention relates to a polycarbonate resin composition and a molded body comprising the resin composition, and in particular, a polycarbonate resin composition excellent in moldability such as thin-walled flame retardancy, thermal conductivity, impact characteristics, and fluidity and releasability. The present invention relates to a product and a molded body comprising the same.

In product development in the electrical and electronic field, heat dissipation due to high pixel count and high speed processing in digital cameras and digital video cameras, miniaturization of projectors, high speed processing in personal computers and mobile devices, and the use of LEDs for various light sources. Emphasis is placed on countermeasures.
Measures to configure the heat dissipation circuit with metal parts are also taken, but in the equipment to be downsized, the heat dissipation circuit becomes complicated, so the resin housing and the heat dissipation circuit can be integrated, making it heat conductive There is a demand for a resin material that is excellent in mechanical strength as a housing.
Further, in a small electronic device, the casing and the chassis are required to be thin, and accordingly, the flame retardancy of the thin molded body is also required.

Polycarbonate resins are widely used for the casings of the above electronic devices. As a method for improving the flame retardancy of polycarbonate resins, halogenated flame retardants such as halogenated bisphenol A and halogenated polycarbonate oligomers are effective for flame retardants. Have been used with flame retardant aids such as antimony oxide. However, recently, from the viewpoint of safety and impact on the environment at the time of disposal / incineration, a flame retardant method using a flame retardant containing no halogen is required from the market. As such non-halogen flame retardants, organophosphorus flame retardants, especially organophosphate compounds, when combined with polycarbonate resin compositions exhibit excellent flame retardancy and also act as plasticizers. It is necessary to blend in. Further, since the polycarbonate resin has a high molding temperature and a high melt viscosity, the molding temperature tends to be high. Although phosphate ester compounds generally contribute to flame retardancy, they may not always be sufficient in terms of molding environment and molded product appearance, such as mold corrosion and gas generation during molding. In addition, problems such as reduction in impact strength and occurrence of discoloration when the molded product is placed in a high temperature environment have been pointed out.
Furthermore, the recent demand for recyclability in resource saving still has problems such as difficulty in recycling due to insufficient thermal stability.
Therefore, it is required to find a polycarbonate resin composition that achieves the required flame retardancy in a thin molded article and has excellent thermal conductivity without using a halogen compound or a phosphate ester compound as a flame retardant. ing.

It is known that graphite is blended as a means for imparting the above heat dissipation to a thermoplastic resin such as a polycarbonate resin (see Patent Document 1 and Patent Document 2). Patent Document 1 discloses that a thermoplastic resin composition having low metal corrosivity and excellent thermal conductivity can be obtained by blending specific graphite with a thermoplastic resin. In order to improve the properties, it is described that it is preferable to use an organic halogen flame retardant such as a halogenated carbonate oligomer or a halogenated epoxy compound or a phosphate ester flame retardant. It does not disclose a technique that does not use a flame retardant and a phosphorus-based flame retardant.
Further, Patent Document 2 relates to a heat radiating housing in which a heating element is accommodated, but there is no description regarding flame retardancy required for a housing such as an electronic device, and organic bromine as an additive to be blended as necessary. Although flame retardants such as flame retardants and phosphorous flame retardants are disclosed, technology that does not actively use chlorine flame retardants, bromine flame retardants and phosphorus flame retardants is not disclosed, and its implementation In the example, since there is no addition of a flame retardant or an anti-drip agent, it is considered that the flame retardant is not sufficient.
Further, Patent Document 3 discloses a flame retardant comprising a polycarbonate resin, graphite, and an alkali (earth) metal salt of an organic sulfonate as a technique not actively using a chlorine-based flame retardant, a bromine-based flame retardant, and a phosphorus-based flame retardant. In the flame retardant evaluation, only evaluation with a molded body having a thickness of 2.5 mm has been made, and a thickness of about 1.5 mm required for a housing of an electronic device or the like is sufficient. Flame retardancy is not obtained. Patent Document 3 describes that a fluorine-containing anti-dripping agent is contained, but it is described that the blending amount is preferably 0.01 to 5 parts by mass in order to achieve both the melt-drip-preventing effect and the flow characteristics. Has been.

JP 2007-31611 A JP 2008-31358 A JP 2006-273931 A

The present invention provides flame retardancy (thickness 1.2 to 1.0 mm, V-0 to V-1; below) without using a chlorine-based flame retardant, bromine-based flame retardant and phosphorus-based flame retardant. An object of the present invention is to provide a polycarbonate resin composition having excellent "thin-flame flame retardancy"), high thermal conductivity, excellent impact properties, and moldability such as fluidity and releasability, and a molded product thereof. And

As a result of intensive studies to achieve the above object, the present inventors have reduced the thickness of the aromatic polycarbonate resin by blending graphite and polytetrafluoroethylene more than the amount usually used as an anti-drip agent. The inventors have found that a polycarbonate resin composition having excellent flame retardancy and also excellent thermal conductivity, impact properties, and moldability such as fluidity and releasability can be obtained, thereby completing the present invention.

That is, the present invention
(1) A polycarbonate resin composition comprising (B) 28 to 90 parts by mass of graphite and (C) 9 to 20 parts by mass of polytetrafluoroethylene with respect to 100 parts by mass of (A) aromatic polycarbonate resin,
(2) The polycarbonate resin composition according to the above (1), further comprising (D) 0.1 to 0.5 parts by mass of an organic alkali (earth) metal salt,
(3) The polycarbonate resin composition according to the above (1) or (2), wherein the graphite is natural graphite,
(4) The polycarbonate resin composition according to the above (1) or (2), wherein the graphite is artificial graphite,
(5) The organic alkali metal salt and / or the organic alkaline earth metal salt is selected from sulfonic acid alkali metal salts, sulfonic acid alkaline earth metal salts, polystyrene sulfonic acid alkali metal salts, and polystyrene sulfonic acid alkaline earth metal salts. The polycarbonate resin composition according to (2), which is at least one kind,
(6) The polycarbonate resin composition according to the above (5), wherein the alkali metal sulfonate is sodium paratoluenesulfonate,
(7) A molded article comprising the polycarbonate resin composition according to any one of (1) to (6) above,
(8) The molded product according to (7), which is a part for electrical / electronic equipment,
(9) The molded product according to (7), which is a casing for an electric / electronic device,
(10) The molded body according to (7), which is a chassis for electric / electronic devices,
Is to provide.

According to the present invention, a resin composition and a molded body excellent in moldability such as thin flame retardancy, thermal conductivity, fluidity and releasability are obtained without impairing the original mechanical properties of the polycarbonate resin. be able to.

Hereinafter, the present invention will be described in detail.
The polycarbonate resin (hereinafter sometimes abbreviated as “PC resin”) composition of the present invention comprises (A) an aromatic polycarbonate resin, (B) graphite, and (C) polytetrafluoroethylene as essential components. It is a polycarbonate resin composition.

The aromatic polycarbonate resin used as the component (A) in the present invention is not particularly limited, and various resins can be used. Usually, an aromatic polycarbonate produced by a reaction between a dihydric phenol and a carbonate precursor is used. Can do. For example, a dihydric phenol and a carbonate precursor are used by a solution method or a melting method, specifically, a reaction of a dihydric phenol and phosgene, or a transesterification reaction of a dihydric phenol and diphenyl carbonate or the like. be able to.

Examples of the dihydric phenol include various ones such as 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], bis (4-hydroxyphenyl) methane, 1,1-bis (4- Hydroxyphenyl) ethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 4,4'-dihydroxydiphenyl, bis (4-hydroxyphenyl) cycloalkane, bis (4-hydroxyphenyl) sulfide Bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfoxide, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) ketone and the like.
Among these, particularly preferred dihydric phenols are bis (hydroxyphenyl) alkanes, particularly those using bisphenol A as a main raw material.
In addition, examples of the dihydric phenol include hydroquinone, resorcin, and catechol. These dihydric phenols may be used alone or in combination of two or more. An appropriate branching agent may be used together with the dihydric phenol. As this branching agent, a trihydric or higher polyhydric phenol, specifically 1,1,1-tris (4-hydroxyphenyl) ethane, α, α ′, α ″ -tris (4-hydroxyphenyl) -1,3,5-triisopropylbenzene, 1- [α-methyl-α- (4′-hydroxyphenyl) ethyl] -4- [α ′ , Α′-bis (4 ″ -hydroxyphenyl) ethyl] benzene, phloroglucin, isatin bis (o-cresol) and the like.
Examples of the carbonate precursor include carbonyl halide, carbonyl ester, haloformate, and the like, and specifically include phosgene, dihaloformate of dihydric phenol, diphenyl carbonate, dimethyl carbonate, diethyl carbonate, and the like.

As the molecular weight regulator used as the molecular end group in the PC resin as the component (A), any molecular weight regulator can be used as long as it is usually used for polymerization of polycarbonate, and various monohydric phenols can be used. Specific examples include phenol, p-cresol, p-tert-butylphenol, p-tert-octylphenol, p-cumylphenol, bromophenol, tribromophenol, and nonylphenol.

In the PC resin composition of the present invention, in addition to the aromatic PC resin, a polycarbonate-polyorganosiloxane copolymer having a polyorganosiloxane portion, terephthalic acid, etc., as long as the object of the present invention is not impaired. It may suitably contain a copolymer resin such as a polyester-polycarbonate resin obtained by polymerizing a polycarbonate in the presence of an ester precursor such as a functional carboxylic acid or an ester-forming derivative thereof, or other polycarbonate resin. it can.

The (A) aromatic PC resin used in the present invention preferably has a raw material molecular weight (viscosity average molecular weight) [Mv] of 17,000 to 30,000 from the viewpoint of obtaining high impact strength. Here, when natural graphite is used as (B) graphite described below, the above-mentioned raw material molecular weight (viscosity average molecular weight) [Mv] is from 19,000 to 26,000 in terms of moldability and impact strength. To preferred. When using artificial graphite, it is preferably 18,500 to 23,000, and if the molecular weight is too high, the flame retardancy tends to decrease.
This viscosity average molecular weight (Mv) is obtained by measuring the viscosity of a methylene chloride solution at 20 ° C. using an Ubbelohde viscometer, obtaining the intrinsic viscosity [η] from this, and calculating the viscosity by the following formula.
[Η] = 1.23 × 10 ⁻⁵ Mv ^0.83

In the polycarbonate resin composition of the present invention, graphite is blended as the component (B) in order to mainly impart thermal conductivity.
As graphite, either natural graphite or various artificial graphites can be used. As natural graphite, any of earth-like graphite, scale-like graphite (Vein Graphite also called massive graphite), and scale-like graphite (Flake Graphite) can be used. Of the natural graphites exemplified above, scaly graphite can be suitably used. By applying natural graphite, higher thermal conductivity and higher elastic modulus can be obtained.

Artificial graphite is obtained by heat-treating amorphous carbon and artificially aligning irregularly arranged fine graphite crystals. In addition to artificial graphite used for general carbon materials, Kish graphite, cracked graphite, and Includes pyrolytic graphite. Artificial graphite used for general carbon materials is usually produced by graphitization treatment using petroleum coke or coal-based pitch coke as a main raw material.
Such artificial graphite has a merit that a high weld strength can be obtained although the flexural modulus and thermal conductivity are lower than those of the natural graphite.
The blending amount of component (B) is required to be in the range of 28 to 90 parts by weight, preferably in the range of 30 to 70 parts by weight, with respect to 100 parts by weight of component (A). When the blending amount is less than 28 parts by mass, it is difficult to obtain sufficient thermal conductivity, and when it exceeds 90 parts by mass, there is a problem that the impact strength tends to decrease. Here, in the case of a resin composition in which the above natural graphite is blended in the range of 40 to 60 parts by mass, the effect of improving the flame retardancy becomes remarkable, and the flame retardancy at a thin wall (thickness 1.2 mm). Evaluation (UL standard 94) can achieve V-0.

In the present invention, graphite having a 50% cumulative diameter of 30 to 180 μm can be suitably used. The fixed carbon amount of graphite is preferably 80% by weight or more, more preferably 90% by weight or more, and still more preferably 98% by weight or more. The volatile content of the graphite of the present invention is preferably 3% by weight or less, more preferably 1.5% by weight or less, and still more preferably 1% by weight or less.
Further, the surface of graphite is subjected to surface treatment such as epoxy treatment, urethane treatment, silane coupling treatment, and oxidation treatment in order to increase the affinity with the thermoplastic resin as long as the characteristics of the composition of the present invention are not impaired. You may give it.

In order to improve flame retardancy, (C) polytetrafluoroethylene (PTFE) is blended in the polycarbonate resin composition of the present invention. This component (C) gives the resin composition of the present invention a melt dripping preventing effect, and exhibits excellent thin flame retardancy.
The component (C) preferably has a fibril forming ability. Here, “fibril forming ability” means that resins tend to be bonded and become fibrous due to an external action such as shearing force. Examples of the component (C) of the present invention include polytetrafluoroethylene, a tetrafluoroethylene copolymer (for example, a tetrafluoroethylene / hexafluoropropylene copolymer) and the like. Of these, polytetrafluoroethylene is preferred.
PTFE having fibril-forming ability has a very high molecular weight, and the number average molecular weight determined from the standard specific gravity is usually 500,000 or more, preferably 500,000 to 15 million, more preferably 1,000,000 to 10 million. Specifically, tetrafluoroethylene is polymerized in an aqueous solvent in the presence of sodium, potassium or ammonium peroxydisulfide at a pressure of about 7 to 700 kPa and a temperature of about 0 to 200 ° C., preferably 20 to 100 ° C. Can be obtained.

In addition to solid forms, those in the form of an aqueous dispersion can also be used, and those classified as type 3 according to the ASTM standard can be used. Commercially available products classified as Type 3 include, for example, “Teflon 6-J” (trade name, manufactured by Mitsui Dupont Fluoro Chemical Co., Ltd.), “Polyflon D-1” and “Polyflon F-103” [trade name. , Manufactured by Daikin Industries, Ltd.]. Other than Type 3, “Algoflon F5” (trade name, manufactured by Solvay Solexis), “Polyflon MPAFA-100” (trade name, manufactured by Daikin Industries, Ltd.) and the like can be mentioned.
The PTFE may be used alone or in combination of two or more.

Component (C) should be blended in an amount of 9 to 20 parts by weight, preferably 10 to 18 parts by weight, per 100 parts by weight of component (A). If the blending amount is less than 9 parts by mass, thin flame retardance cannot be ensured, and if it exceeds 20 parts by mass, the flow characteristics of the molten resin composition are lowered and the moldability is deteriorated.
This blending amount is extremely large compared with the amount of PTFE usually blended and formulated as a dripping inhibitor (usually blending amount of 0.5% by mass or less of the entire PC resin composition). In addition to flame retardancy, there is an advantage that the release action during molding is improved because the dynamic friction coefficient is reduced.

As described above, if the blending amount of the graphite of the component (B) is 28 to 90 parts by weight and the component (C) is 9 to 20 parts by weight with respect to 100 parts by weight of the component (A), the PC resin is usually used. Flame retardant evaluation (UL standard 94) with a thin wall (thickness 1.2 mm) can achieve V-1 without the use of flame retardants used, such as the following organic alkali (earth) metal salts. It becomes.

In order to further improve the thin flame retardancy of the polycarbonate resin composition of the present invention, it is preferable to blend (D) an organic alkali metal salt and / or an organic alkaline earth metal salt.
Various organic alkali metal salts and / or organic alkaline earth metal salts may be used, but organic acids having at least one carbon atom, or alkali metal salts and organic alkaline earth metal salts of organic acid esters are used. can do.
Here, the organic acid or the organic acid ester is an organic sulfonic acid, an organic carboxylic acid, or the like. On the other hand, the alkali metal is lithium, sodium, potassium, cesium or the like, and the alkaline earth metal is magnesium, calcium, strontium, barium or the like. Among these, sodium and potassium salts are preferably used. The salt of the organic acid may be substituted with a halogen such as fluorine, chlorine or bromine. Alkali metal salts and organic alkaline earth metal salts can be used singly or in combination of two or more.
Among the above-mentioned various organic alkali metal salts and organic alkaline earth metal salts, for example, in the case of organic sulfonic acid, paratoluenesulfonic acid, 2,5-dichlorobenzenesulfonic acid; 2,4,5-trichlorobenzenesulfonic acid Diphenylsulfone-3-sulfonic acid; diphenylsulfone-3,3′-disulfonic acid; alkali metal salts of organic sulfonic acids such as naphthalene trisulfonic acid, and the like.

Examples of the organic carboxylic acid include perfluoroformic acid, perfluoromethanecarboxylic acid, perfluoroethanecarboxylic acid, perfluoropropanecarboxylic acid, perfluorobutanecarboxylic acid, perfluoromethylbutanecarboxylic acid, perfluorohexanecarboxylic acid. Perfluoroheptanecarboxylic acid, perfluorooctanecarboxylic acid and the like, and alkali metal salts of these organic carboxylic acids are used.

Next, as the alkali metal salt and / or alkaline earth metal salt of polystyrene sulfonic acid that can be used as the component (D), a sulfonate group-containing aromatic vinyl resin represented by the following general formula (1) may be used. it can.

In the above formula (1), Z ¹ represents a sulfonate group, Z ² represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. g is an integer of 1 to 5. h represents a mole fraction, and 0 <h ≦ 1.
Here, the sulfonate group is an alkali metal salt and / or alkaline earth metal salt of sulfonic acid, and examples of the metal include sodium, potassium, lithium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium and the like. It is done.
In the formula, Z ² is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, preferably a hydrogen atom or a methyl group. Further, g is an integer of 1 to 5, and h has a relationship of 0 <h ≦ 1. That is, the sulfonate group (Z ¹ ) may be a fully substituted or partially substituted aromatic ring.
In order to further enhance the thin flame retardant effect of the polycarbonate resin composition of the present invention, the substitution ratio of the sulfonate group is determined in consideration of the content of the sulfonate group-containing aromatic vinyl resin, etc. A 10 to 100% -substituted one is used.

In addition, in the alkali metal salt and / or alkaline earth metal salt of polystyrene sulfonic acid, the sulfonate group-containing aromatic vinyl resin is not limited to the polystyrene resin represented by the general formula (1). It may be a copolymer with another monomer copolymerizable with the monomer.
Here, as a method for producing a sulfonate group-containing aromatic vinyl resin, (I) the above aromatic vinyl monomer having a sulfonic acid group or the like, or another monomer copolymerizable therewith (II) Aromatic vinyl polymers, copolymers of aromatic vinyl monomers and other copolymerizable monomers, or mixed polymers of these And neutralizing with an alkali metal compound and / or an alkaline earth metal compound.
For example, as the method (II), a polystyrene sulfone oxide is produced by adding a mixture of concentrated sulfuric acid and acetic anhydride to a 1,2-dichloroethane solution of polystyrene resin, heating the mixture, and reacting for several hours. Then, polystyrene sulfonate potassium salt or sodium salt can be obtained by neutralizing with sulfonic acid group and equimolar amount of potassium hydroxide or sodium hydroxide.
The weight average molecular weight of the sulfonate group-containing aromatic vinyl resin used in the present invention is about 1,000 to 300,000, preferably about 2,000 to 200,000.
The weight average molecular weight can be measured by the GPC method.

The above component (D) may be used singly or in combination of two or more. The content thereof is 0.1 to 0.5 parts by mass, preferably 0.2 to 0.4 parts by mass with respect to 100 parts by mass of component (A). When the content is 0.1 parts by mass or more, an effect of improving thin-walled flame retardancy is observed, and when it is 0.5 parts by mass or less, thermal stability can be secured.

The polycarbonate resin composition of the present invention includes the essential components (A) to (C) described above for the purpose of moldability, impact resistance, appearance improvement, weather resistance improvement and rigidity improvement, and further, if necessary. In addition to the component (D) to be blended, a phenol-based, phosphorus-based or sulfur-based (E) antioxidant, and (F) a release agent can be contained.
(E) The amount of antioxidant added is preferably 0.001 to 0.5 parts by mass for phosphorus antioxidants. If it is 0.001 part by mass or more, thermal stability in the granulation step / molding step can be maintained, and if it is less than 0.5 part by mass, it is difficult to cause a decrease in molecular weight. In addition, in the case of a phenolic antioxidant, it is preferable to add 0.001 to 0.5 parts by mass, and the impact strength is easily improved.
(F) The release agent is not particularly limited as long as it can be mixed with a polycarbonate resin to improve the release property at the time of molding. In particular, organic compounds such as beeswax, glycerin monostearate, glycerin tristearate, pentaerythritol monostearate, pentaerythritol tristearate, pentaerythritol tetrastearate, montanic acid ester wax, carboxylic acid ester have excellent release properties. Shown and used preferably. These include, for example, “honey wax golden brand” manufactured by Miki Chemical Industry Co., Ltd., “Rikemar S-100A”, “Riquemar SL-900”, and “Riquestar EW-440A” manufactured by Riken Vitamin Co., Ltd., Cognis Japan “Roxyol V P G 8 6 1” manufactured by Clariant Japan, “Rico Wax E” manufactured by Clariant Japan, and “Roxyol EP-32” manufactured by Cognis Japan. The blending amount is preferably 0.001 to 2 parts by mass.

Furthermore, additive components commonly used in other synthetic resins, elastomers, and thermoplastic resins can be included as necessary. The above additives include antistatic agents, polyamide polyether block copolymers (permanent antistatic performance), benzotriazole and benzophenone UV absorbers, hindered amine light stabilizers (weathering agents), plasticizers, antibacterial agents Agents, compatibilizers and colorants (dyes, pigments) and the like.
The amount of the optional component is not particularly limited as long as the characteristics of the polycarbonate resin composition of the present invention are maintained.

Next, the manufacturing method of the polycarbonate resin composition of this invention is demonstrated.
The polycarbonate resin composition of the present invention comprises the above-mentioned components (A) to (C), the component (D) as necessary in the above proportions, and various optional components used as necessary in appropriate proportions. It is obtained by kneading.
Compounding and kneading are premixed with commonly used equipment such as a ribbon blender, drum tumbler, etc., Henschel mixer, Banbury mixer, single screw extruder, twin screw extruder, multi screw extruder and It can be performed by a method using a conida or the like. The heating temperature at the time of kneading is usually appropriately selected within the range of 240 to 320 ° C. As the melt-kneading molding, it is preferable to use an extrusion molding machine, particularly a vent type extrusion molding machine.
In addition, the components other than the polycarbonate resin can be added in advance as a master batch with melt-kneading with the polycarbonate resin or other thermoplastic resin.

The polycarbonate resin composition of the present invention is an injection molding method, an injection compression molding method, an extrusion molding method, a blow molding method, a press molding method, a vacuum molding method, using the above melt kneading molding machine or the obtained pellets as a raw material. Various molded products can be manufactured by a foam molding method or the like. In particular, the obtained pellets can be used suitably for the production of injection molded products by injection molding and injection compression molding.
The molded body comprising the polycarbonate resin composition of the present invention is, for example,
(1) TV, radio cassette, video camera, video tape recorder, audio player, DVD player, air conditioner, mobile phone, display, computer, register, calculator, copier, printer, facsimile, etc.
(2) The housing for the electric / electronic device according to 1 above,
(3) Chassis for electrical / electronic equipment according to 1 above,
Etc. can be suitably used.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not restrict | limited at all by these.
The performance evaluation method and raw materials used are shown below.
[Performance evaluation method]
(1) Thin-flame flame retardancy A vertical combustion test was performed using a test piece (length 127 mm, width 12.7 mm, thickness 1.2 mm) prepared according to UL standard 94. Based on the test results, UL94 V-0, V-1, or V-2 grades were evaluated, and those that did not reach V-2 were designated as V-2out.
The UL standard 94 is a method for evaluating the flame retardancy from the afterflame time after the burner flame is indirectly fired for 10 seconds on a test piece of a predetermined size held vertically.

(2) Thermal conductivity The thermal conductivity was measured by a hot disk method using a thermal conductivity measuring device “TPA-501” [manufactured by Kyoto Electronics Industry Co., Ltd.].
(3) Tensile properties Measured according to ASTM D638.

(4) Bending characteristics a) Bending strength Measured according to ASTM D790.
b) Flexural modulus Using a test piece with a thickness of 4 mm and a length of 130 mm produced by an injection molding machine, a three-point bending test was performed in accordance with ASTM standard D-790 at a distance between fulcrums of 90 mm and a load speed of 20 mm / min. The bending elastic modulus was calculated from the gradient of the load-strain curve.

(5) Weld characteristics A test piece is molded so that a weld is formed at the center of a test piece having a length of 127 mm, a width of 12.3 mm, and a thickness of 1.2 mm, and the weld strength (bending strength) is determined in accordance with ASTM D790. It was measured.

(6) Impact characteristics a) Notched Izod impact strength (IZOD)
Impact strength was measured at a measurement temperature of 23 ° C. in accordance with ASTM standard D-256 using a 3.2 mm (1/8 inch) thick test piece produced by an injection molding machine.
b) Unnotched Izod impact strength (IZOD)
Impact strength was measured at a measurement temperature of 23 ° C. in accordance with ASTM standard D-256 using a 3.2 mm (1/8 inch) thick test piece produced by an injection molding machine.
c) Charpy (flatwise method) impact strength Impact strength was measured by a flatwise method in accordance with JIS K7111, using a 3.2 mm (1/8 inch) thick test piece produced by an injection molding machine.

(7) Flow characteristics (flow value)
Using a Koka flow tester, measurement was performed at a temperature of 320 ° C. and a load of 100 kg in accordance with JIS-K7210.
(8) Releasability According to JIS K7218-A method, a sliding test was carried out at room temperature at a surface pressure of 250 kPa and a speed of 0.5 m / sec.

[Raw materials]
(A) Component A-1: Aromatic polycarbonate resin [Idemitsu Kosan Co., Ltd., “FN1900A”, Mv = 19,500]
A-2: Aromatic polycarbonate resin [Idemitsu Kosan Co., Ltd., “FN2200A”, Mv = 21,500]
A-3: Aromatic polycarbonate resin [Idemitsu Kosan Co., Ltd., “FN2500A”, Mv = 24,500]
A-4: Aromatic polycarbonate resin [Idemitsu Kosan Co., Ltd., “FN2600A”, Mv = 26,000]

Component (B) Graphite B-1: Natural graphite [Nippon Graphite Industries Co., Ltd. “CB-150”; scale-like, particle size distribution 63 μm or less 77 to 87%, 106 μm or more 5% or less, apparent density 0.2 to 0.3 g / Cm ³ , 50% cumulative diameter 31-48 μm, fixed carbon 98 mass% or more, ash content 1 mass% or less, volatile content 1 mass% or less]
B-2: Artificial graphite [“PAG-420” manufactured by Nippon Graphite Industries Co., Ltd .; irregular shape, 50% cumulative diameter 30-40 μm (50 μm or more and 50% or less), apparent density 0.29 to 0.37 g / cm ³ , fixed Carbon 99.4 mass% or more, ash content 0.3 mass% or less, volatile content 0.3 mass% or less]

(C) Component PTFE
PTFE [“Algoflon F5” manufactured by Solvay Solexis, Inc .; Algoflon F5 is prone to agglomerate, so it is once masterbatched with PC flakes (mixing ratio (mass) PC: PTFE = 90: 10 to 80:20). From]

(D) Component Organic alkali (earth) metal salt Paratoluenesulfonic acid sodium salt [DAH DIING CHEMICAL INDUSTRY, purity 93%, sodium sulfate 3% by mass or less, moisture 5% by mass or less]

Component (E) Other additives Antioxidant E-1: Phosphorous antioxidant (diphenylisooctyl phosphite) [Adeka Corporation, “Adeka Stub C”]
E-2: Phenolic antioxidant (octadecyl-3- (3,5-di-t-butyl-hydroxyphenyl) propionate) [“Irganox 1076” manufactured by Ciba Japan Co., Ltd.]
Component (F) Other additives Mold release agent F-1: stearic acid monoglyceride [“Rikemar S-100A” manufactured by Riken Vitamin Co., Ltd.]
F-2: Pentaerythritol tetrastearate [Rikenstar EW-440A manufactured by Riken Vitamin Co., Ltd.]

Examples 1 to 15 and Comparative Examples 1 to 9
Each component is mixed in the proportions shown in Tables 1 and 2 and supplied to a vent type twin screw extruder (Toshiba Machine Co., Ltd .: TEM35), barrel temperature 300 to 320 ° C., screw rotation speed 200 to 600 rotations, discharge The mixture was melt-kneaded at an amount of 10 to 30 kg / hr to obtain a pellet sample for evaluation.
Using this pellet sample for evaluation, a test piece for performing each test at a molding resin temperature of 320 ° C. was prepared by an injection molding machine, and each test was performed. The results are shown in Tables 1 and 2.

Tables 1 and 2 revealed the following.
In Examples 1 to 15, all the evaluation items were excellent. In particular, in Examples 1 to 6 including the components (A) to (C), even if the component (D) of the flame retardant was not included, the thin wall (thickness) 1.2 mm) A polycarbonate resin composition excellent in flame retardancy, thermal conductivity, bending characteristics, and impact strength is obtained. In Examples 8 to 10, the thin-wall flame retardancy was particularly excellent, and V-0 could be achieved.
In Comparative Examples 1 and 7 where the graphite content of the component (B) is low, the thermal conductivity is lowered, and in Comparative Examples 2 and 8 where the component (B) is too much, the impact characteristics are lowered. In Comparative Example 3, Comparative Example 5 and Comparative Example 6 in which the PTFE content of the component (C) is low, the thin-wall flame retardancy is reduced, and in Comparative Examples 4 and 9 in which the component (C) is too much, the flow characteristics are reduced. And formability is poor.
Further, from the comparison between Example 1, Example 4, Example 5 and Comparative Example 3, by setting the PTFE of the component (C) to an amount within the range of the present invention, the dynamic friction coefficient is reduced, and the mold release It is understood that the performance is improved.

Claims

(A) A polycarbonate resin composition obtained by blending 28 to 90 parts by mass of graphite and (C) 9 to 20 parts by mass of polytetrafluoroethylene with respect to 100 parts by mass of the aromatic polycarbonate resin.
The polycarbonate resin composition according to claim 1, further comprising (D) 0.1 to 0.5 parts by mass of an organic alkali (earth) metal salt.
The polycarbonate resin composition according to claim 1 or 2, wherein the graphite is natural graphite.
The polycarbonate resin composition according to claim 1 or 2, wherein the graphite is artificial graphite.
The organic alkali metal salt and / or the organic alkaline earth metal salt is at least one selected from an alkali metal sulfonate, an alkaline earth metal sulfonate, an alkali metal polystyrene sulfonate, and an alkaline earth metal polystyrene sulfonate. The polycarbonate resin composition according to claim 2.
The polycarbonate resin composition according to claim 5, wherein the alkali metal sulfonate is p-toluenesulfonic acid sodium salt.
A molded body comprising the polycarbonate resin composition according to any one of claims 1 to 6.
The molded body according to claim 7, which is a part for an electric / electronic device.
The molded body according to claim 7, which is a casing for an electric / electronic device.
The molded article according to claim 7, which is a chassis for electrical and electronic equipment.