JP7146453B2 - Flame-retardant polycarbonate resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flame-retardant polycarbonate resin composition and a resin molded product obtained by molding the resin composition.

Polycarbonate resins are thermoplastic resins having excellent mechanical strength, heat resistance, thermal stability, etc., and are therefore widely used industrially in the fields of electrics, electronics, automobiles, and the like. Polycarbonate resins reinforced with glass fibers are used for the housings of electrical and electronic devices, power tools, and the like because of their excellent strength and rigidity. In these fields, there are applications that require high flame retardancy. For example, evaluation of flame retardancy in accordance with the UL94 test (combustibility test of plastic materials for equipment parts) stipulated by Underwriters Laboratories. , flame retardancy conforming to V-0 and V-1 is required. Furthermore, the casings of electronic devices such as mobile phones are required to have excellent appearance.

However, conventional glass fiber reinforced polycarbonate resin compositions have not been sufficiently studied in terms of flame retardancy and the appearance of molded products. cannot meet the demand.

In order to improve the flame retardancy of a glass fiber reinforced polycarbonate resin composition, a plurality of methods are known in which a phosphorus flame retardant or a fluorine-containing anti-dripping agent is added to the polycarbonate resin. Patent Documents 1 and 2 propose a glass fiber-reinforced polycarbonate resin composition having excellent strength and flame retardancy, which consists of polycarbonate resin, glass fiber, and a phosphorus-based flame retardant. The glass fiber-reinforced polycarbonate resin composition of Patent Document 1 may contain a fluorine-containing anti-dripping agent, and the glass fiber-reinforced polycarbonate resin composition of Patent Document 2 may contain polytetrafluoroethylene. Have been described. Patent Literature 3 proposes a glass fiber-reinforced polycarbonate resin composition having excellent strength and flame retardancy, comprising a polycarbonate resin, glass fibers, and a phosphorus-based flame retardant.

However, these resin compositions are not satisfactory in terms of mechanical strength such as impact strength, and the appearance of molded articles is also unsatisfactory.

Japanese Patent Application Laid-Open No. 2007-070468 JP 2011-001514 A Japanese Patent Publication No. 2009-521568

The present invention provides a flame-retardant polycarbonate resin composition excellent in flame retardancy and appearance of molded articles without impairing the excellent mechanical strength and rigidity of the glass fiber-reinforced polycarbonate resin composition, and a resin composition thereof. To provide a resin molded product formed by molding.

The present inventors have conducted intensive research to solve the above problems, and found that by incorporating a silicone-based flame retardant and polytetrafluoroethylene in specific blending amounts into a resin composition composed of a polycarbonate resin and glass fibers, , found that a flame-retardant polycarbonate resin composition having excellent flame retardancy and excellent molded product appearance can be obtained without impairing the excellent mechanical strength and rigidity of the glass fiber-reinforced polycarbonate resin composition, and completed the present invention. did.

That is, in the present invention, 0.5 to 8 silicone flame retardants (C) are added to 100 parts by mass of a resin composition comprising 30 to 70% by mass of a polycarbonate resin (A) and 30 to 70% by mass of glass fibers (B). A flame-retardant polycarbonate resin composition containing parts by mass and polytetrafluoroethylene (D), wherein the content of polytetrafluoroethylene (D) in the composition is 0.1 to 1.0 mass% It relates to a flame-retardant polycarbonate resin composition.

It is preferable that the glass fibers (B) are treated with an epoxy-based sizing agent or a urethane-based sizing agent and have an average cross-sectional diameter of 6 to 20 μm.

It is preferable that the glass fiber (B) has a flat cross-section with an average long diameter of 10 to 50 μm and a ratio of long diameter to short diameter (long diameter/short diameter) of 2 to 8 on average.

Furthermore, it is preferred that at least one (E) thermoplastic resin selected from the group consisting of styrene-acrylonitrile copolymers, polymethacrylic styrene, polyesters, polyester elastomers, polyamides, and ethylene vinyl acetate polymers is included.

It is preferable that the average particle size of the thermoplastic resin (E) is 5 μm or less.

The content of the thermoplastic resin (E) is preferably 0.005 to 5% by mass in the flame-retardant polycarbonate resin composition.

Furthermore, it is preferable to contain a phosphate flame retardant.

An arbitrary 127 μm × 95 μm field of view of a fracture surface obtained by freeze-fracture in the direction perpendicular to the flow direction of the resin composition for testing prepared without blending glass fibers in the resin composition and observed with a scanning electron microscope. The diameter of the thickest portion of the polytetrafluoroethylene (D) fibrils present in the polytetrafluoroethylene (D) is preferably 5 μm or less, more preferably 2 μm or less.

The average particle size of polytetrafluoroethylene (D) is preferably 200 μm or less.

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 contains a silicone-based flame retardant and polytetrafluoroethylene in specific compounding amounts, the excellent mechanical strength and rigidity of the glass fiber-reinforced polycarbonate resin composition are impaired. It is possible to provide a resin molded article excellent in flame retardancy and appearance of the molded article.

Hereinafter, the present invention will be described in detail by showing embodiments and examples, etc., but the present invention is not limited to the embodiments and examples shown below, and within the scope of the present invention. It can be implemented with arbitrary changes.

The flame-retardant polycarbonate resin composition of the present invention comprises 100 parts by mass of a resin composition comprising 30 to 70% by mass of polycarbonate resin (A) and 30 to 70% by mass of glass fiber (B), and a silicone flame retardant (C ) 0.5 to 8 parts by mass, and a flame-retardant polycarbonate resin composition containing polytetrafluoroethylene (D), wherein the content of polytetrafluoroethylene (D) in the composition is 0.1 It is characterized by being ~1.0% by mass.

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

As dihydroxydiaryl compounds, in addition to bisphenol A, 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(4 -Bis(hydroxyaryl)alkanes such as hydroxy-3,5-dichlorophenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane bis(hydroxyaryl)cycloalkanes, dihydroxydiaryl ethers such as 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, and 4,4'-dihydroxydiphenyl sulfide Dihydroxydiarylsulfides, dihydroxydiarylsulfoxides such as 4,4'-dihydroxydiphenylsulfoxide, 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfoxide, 4,4'-dihydroxydiphenylsulfone, 4,4' -dihydroxydiaryl sulfones such as -dihydroxy-3,3'-dimethyldiphenyl sulfone.

These may be used alone or in admixture of two or more. In addition to these, piperazine, dipiperidylhydroquinone, resorcinol, 4,4'-dihydroxydiphenyl and the like may be used in admixture.

Further, the above dihydroxyaryl compound and a trihydric or higher phenolic compound as shown below may be used in combination. Examples of trihydric or higher phenols include phloroglucine, 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 (Mv) of the polycarbonate resin (A) is not particularly limited, but is preferably 10,000 to 100,000, more preferably 15,000 to 35,000, and even more preferably 15,000 to 25,000 in terms of moldability and strength. Moreover, when producing such a polycarbonate resin, a molecular weight modifier, a catalyst, and the like can be used as necessary. The viscosity average molecular weight (Mv) of the polycarbonate resin is a 0.5% by mass methylene chloride solution, and the specific viscosity (ηsp) is measured at a temperature of 20 ° C. using a Canon Fenske viscosity tube. It is a value calculated from the following SCHNELL formula after determining the viscosity [η].
[η]=1.23×10 ⁻⁴ ×Mv ^0.83

The ratio of the polycarbonate resin contained in the flame-retardant polycarbonate resin composition of the present invention is 30 to 70% by mass. If it exceeds 7% by mass, the rigidity is poor, and if it is less than 30% by mass, it becomes difficult to produce the composition.

The form of the polycarbonate resin (A) is not particularly limited, and examples thereof include pellets, flakes, and beads. Among them, flakes are preferable, and porous flakes are more preferable, in that homogeneous dispersibility can be obtained. The bulk density of the polycarbonate is also not particularly limited, but is preferably 0.1 to 0.9, more preferably 0.1 to 0.7. Here, the bulk density refers to a value measured in accordance with JIS K7370 compacted apparent bulk density. Although the size of the polycarbonate is not particularly limited, it is preferably 5 mm or less.

The glass fiber (B) used in the present invention is not particularly limited, and a circular cross-section glass fiber having a substantially circular cross section with an average ratio of the major axis to the minor axis (long axis/short axis) of the fiber cross section of 1 to 1.5 However, it may be a flat cross-section glass fiber having an average value of 2 to 8 in the ratio of the major axis to the minor axis (major axis/minor axis).

The number average fiber length of the glass fibers (B) is preferably 1 to 8 mm, more preferably 2 to 5 mm. Glass fibers are manufactured according to any conventionally known method. If the number average fiber length is less than 1 mm, the mechanical strength is not sufficiently improved, and when producing a polycarbonate resin with a number average fiber length exceeding 8 mm, the dispersibility of the glass fibers in the polycarbonate resin is poor, so the glass fibers fall out of the resin. As a result, productivity tends to decrease.

If the glass fiber (B) is a circular cross-section glass fiber with an average ratio of the major axis to the minor axis (major axis / minor axis) of the fiber cross section of 1 to 1.5 and the cross section is almost circular, the average diameter of the glass fiber is It is preferably 6 to 20 μm. If the average diameter of the glass fibers is less than 6 µm, the mechanical strength is poor, and if it exceeds 20 µm, the appearance tends to deteriorate. The average diameter of the glass fibers is more preferably 7-18 μm, still more preferably 8-15 μm.

Commercially available circular cross-section glass fibers having a substantially circular cross section with an average ratio of the major axis to the minor axis (major axis/minor axis) of the fiber cross section of 1 to 1.5 include those with a diameter of 10 μm and those with a diameter of 13 μm. and their number average length is 2 to 6 mm. Commercially available glass fibers include, for example, CS321 and CS311 manufactured by KCC and CS03MAFT737 manufactured by Owens Corning Japan.

When the glass fiber (B) is a flat cross-section glass fiber having an average value of the ratio of the major axis to the minor axis (major axis/minor axis) of the fiber cross section of 2 to 8, the average value of the major axis is 10 to 50 μm, preferably 15 to 15 μm. 40 μm, more preferably 25-30 μm. Also, the average value of the ratio of the major axis to the minor axis (major axis/minor axis) is 2-8, preferably 2-7, more preferably 2.5-5. These are manufactured according to any conventionally known method.

If the major axis of the flat cross-section glass fiber is less than 10 μm, production is difficult, and if it exceeds 50 μm, the surface appearance of the molded product of the polycarbonate resin composition may be impaired. If the ratio of major axis to minor axis is less than 2, the dimensional stability may be inferior, and if it exceeds 8, the strength may be inferior.

Examples of commercially available flat cross-section glass fibers having an average value of the ratio of the major axis to the minor axis (major axis/minor axis) of the fiber cross section of 2 to 8 include CSG 3PA-820 and CSG 3PA- manufactured by Nitto Boseki Co., Ltd. 830 and the like.

The glass fiber (B) can be surface-treated with a silane coupling agent such as aminosilane or epoxysilane for the purpose of improving adhesion to the polycarbonate resin. Further, when handling glass fibers, they can be bundled with a sizing agent such as urethane or epoxy for the purpose of improving handling properties.

The blending amount of the glass fiber (B) is 30 to 70% by mass in the resin composition comprising the polycarbonate resin (A) and the glass fiber (B). If it exceeds 70% by mass, molded articles with poor appearance will be produced, and if it is less than 30% by mass, the strength and rigidity will be poor. A more preferable blending amount is 35 to 65% by mass, most preferably 40 to 60% by mass.

The silicone-based flame retardant (C) used in the present invention is not particularly limited. Silicone compounds are preferred.

More specifically, the silicone-based flame retardant has a branched main chain and contains an aromatic group as an organic functional group, as represented by the following general formula.

（ｌ、ｍ、ｎは、それぞれ０または１以上の整数で、かつ、ｌ＋ｍ≧１である。）

(l, m, and n are each an integer of 0 or 1 or more, and l+m≧1.)

That is, those having T units and/or Q units as branch units are preferred. These are preferably contained in an amount of 20 mol % or more of the total siloxane units. If the amount is less than 20 mol %, the heat resistance of the silicone compound is lowered and the flame retardant effect is lowered, and the viscosity of the silicone compound itself is too low, which may adversely affect the kneadability with polycarbonate and the moldability. . It is more preferably 30 mol % or more and 95 mol % or less. If 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 this is greatly improved. However, when it exceeds 95 mol %, the degree of freedom of the main chain of the silicone is reduced, and condensation of the aromatic groups during combustion may be difficult to occur, and it may be difficult to develop remarkable flame retardancy.

In addition, it is preferable that the aromatic group accounts for 20 mol % or more of the organic functional groups of the silicone compound. If it is less than this range, the condensation of the aromatic groups becomes difficult to occur during combustion, and the flame retardant effect may decrease. More preferably 40 to 95 mol %. If it is 40 mol % or more, the aromatic group can be more efficiently condensed during combustion, 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. can. If it exceeds 95 mol %, steric hindrance between aromatic groups may make it difficult for these condensation to occur, and it may become difficult to exhibit a remarkable flame retardant effect.

The aromatic group may be phenyl, biphenyl, naphthalene, or derivatives thereof, but the phenyl group is preferred from the standpoint of safety of the silicone compound. Of the organic functional groups in the silicone compound attached to the main chain or branched side chains, the preferred organic group other than the aromatic group is the methyl group, and the terminal groups are methyl, phenyl, hydroxyl, and alkoxy. It is preferably one or a mixture of two to four groups selected from groups (especially methoxy groups). 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 dispersed uniformly in the polycarbonate resin (A). As a result, it can have a better flame retardant effect and also improve moldability. A methyl group is particularly preferred. In this case, the reactivity is extremely low, so the dispersibility is extremely good, and the flame retardancy can be further improved.

The weight average molecular weight of the silicone compound is preferably 3,000 to 500,000. If it is less than 3,000, the heat resistance of the silicone compound itself is lowered and the flame retardant effect is lowered. Furthermore, the melt viscosity is too low, and the silicone compound exudes to the surface of the molded body of the polycarbonate resin (A) during molding. On the other hand, if it exceeds 500,000, the melt viscosity increases and uniform dispersion in the polycarbonate resin (A) is impaired, resulting in reduced flame retardancy and moldability. More particularly preferably 10,000 to 270,000. Since the melt viscosity of the silicone compound is optimal within this range, the silicone compound can be dispersed extremely uniformly in the polycarbonate resin (A) without excessive seepage to the surface, resulting in better flame retardancy and moldability. can be achieved.

The content of the silicone flame retardant (C) is 0 with respect to 100 parts by mass of the resin composition comprising the polycarbonate resin (A) and the glass fiber (B) from the viewpoint of imparting excellent flame retardancy and excellent appearance. .5 to 8 parts by mass, preferably 1 to 6 parts by mass. If the amount is less than 0.5 parts by mass, the desired flame retardancy cannot be obtained.

As the flame retardant, it is preferable to use a phosphate ester flame retardant together with the silicone flame retardant in order to obtain a higher level of flame retardancy. Phosphate flame retardants are not particularly limited, but examples include aromatic condensed phosphates such as resorcinol bis-diphenyl phosphate, resorcinol bis-dixylenyl phosphate, bisphenol A bis-diphenyl phosphate, triphenyl phosphate, trichrone Aromatic phosphate esters such as zyl phosphate and trixylenyl phosphate are included.

The content of the phosphate ester-based flame retardant is not particularly limited, but is preferably 4 parts by mass or less, and 1 to 4 parts by mass with respect to 100 parts by mass of the resin composition comprising the polycarbonate resin (A) and the glass fiber (B). is preferred. If it exceeds 4 parts by mass, the impact strength tends to decrease.

The polytetrafluoroethylene (D) used in the present invention is not particularly limited, and polytetrafluoroethylene homopolymers may be used. You can use whatever you have. Polytetrafluoroethylene may also be a copolymer.

The form of polytetrafluoroethylene (D) is not particularly limited, but particles are preferred. The average particle size is preferably 200 µm or less, more preferably 100 µm or less. If the thickness is 200 μm or less, excellent flame retardancy and excellent appearance can be imparted. Here, the average particle size is obtained by adding 50 ml of methylene chloride to 1 g of the composite resin particles, leaving it at 23 ° C. for 3 hours, and stirring the resulting solution with a stirrer for 20 minutes. The major and minor diameters of the remaining 100 PTFE particles are measured, and (longer diameter + minor diameter)/2 is defined as the particle diameter, and the mean value of the particle diameters of the 100 PTFE particles is referred to.

Although 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., Ltd., 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-described measuring method.

Polytetrafluoroethylene (D) is used as an aqueous dispersion in terms of relatively uniform dispersibility, that is, less generation of polytetrafluoroethylene aggregates and excellent uniform dispersibility and reproducibility. is preferred. The solid content of polytetrafluoroethylene (D) in the aqueous dispersion is not particularly limited, but is preferably 20 to 70% by mass, more preferably 20 to 65% by mass.

The content of polytetrafluoroethylene (D) contained in the flame-retardant polycarbonate resin composition of the present invention is flame retardant from the viewpoint of imparting excellent flame retardancy and excellent appearance to the polycarbonate resin composition. It is 0.1 to 1.0% by mass, more preferably 0.1 to 0.6% by mass, in the polycarbonate resin composition.

The flame-retardant polycarbonate resin composition of the present invention preferably contains a thermoplastic resin (E) in order to exhibit the function of dispersing polytetrafluoroethylene with high uniformity in the resin composition.

Although the thermoplastic resin (E) is not particularly limited, it is preferable to use those having affinity with polycarbonate resins and fluororesins. Examples include styrene-acrylonitrile copolymer (SAN), polymethacrylic styrene polymer (MS), polyester, polyester elastomer, polyamide, ethylene vinyl acetate polymer (EVA) and the like. Among these, styrene-acrylonitrile copolymer (SAN) is particularly preferred. As the thermoplastic resin, one type may be used alone, or two or more types may be used in combination.

Although the form of the thermoplastic resin (E) is not particularly limited, 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. When the particle size is 5 μm or less, the fluororesin can be suitably dispersed in the polycarbonate resin composition, and excellent flame retardancy and excellent appearance can be imparted.

The thermoplastic resin (E) is preferably used in the form of an aqueous dispersion because it reduces the generation of polytetrafluoroethylene aggregates in the flame-retardant resin composition and provides uniform dispersibility. Although the solid content concentration of the thermoplastic resin is not particularly limited, it is preferably 20 to 70% by mass. Further, the amount of the thermoplastic resin is preferably 0.005 to 5 parts by mass with respect to 100 parts by mass of the polycarbonate (A) in the flame-retardant polycarbonate resin composition.

The proportion of the thermoplastic resin (E) contained in the flame-retardant polycarbonate resin composition of the present invention is 0.005 to 5 mass from the viewpoint of imparting excellent flame retardancy and excellent appearance to the polycarbonate resin composition. %, more preferably 0.03 to 1% by mass.

Polytetrafluoroethylene (D) can disperse polytetrafluoroethylene particles, which have a low affinity for the polycarbonate resin composition, in the polycarbonate resin composition with high uniformity. It is preferably used as resin particles. When the composite resin particles are blended in the polycarbonate resin composition, when the polycarbonate resin particles in the composite resin particles melt into the polycarbonate resin composition, the polytetrafluoroethylene particles are high in the polycarbonate resin composition. It is uniformly dispersed and effectively suppresses agglomeration of polytetrafluoroethylene particles during mixing. In addition, when the composite particles contain a thermoplastic resin, the effect of the thermoplastic resin increases the affinity with the polycarbonate resin composition, thereby enabling dispersion with higher uniformity. As a result, the appearance of the polycarbonate resin composition containing polytetrafluoroethylene particles deteriorates (fluororesin protrudes on the surface of the molded product to form streaky lines, surface hues vary, etc.). can be effectively suppressed.

The average particle size of the polycarbonate resin particles used in the composite resin particles is not particularly limited, but from the viewpoint of imparting excellent flame retardancy and excellent appearance to the polycarbonate resin composition, it is preferably 5 mm or less, and 3 mm. The following are more preferred. When the polycarbonate resin particles have such a particle size, the composite resin particles of the present invention can be easily dispersed uniformly in the polycarbonate resin composition.

The bulk density of the polycarbonate resin particles is preferably 0.1 to 0.9, more preferably 0.1 to 0.7. If it is less than 0.1 or more than 0.9, a uniformly dispersed state cannot be expressed, or the material feedability during processing becomes unstable. Here, the bulk density refers to a value measured according to JIS K7370 compacted apparent bulk density.

The ratio of the polycarbonate resin particles contained in the composite resin particles is preferably 0 to 99.5% by mass, more preferably 70 to 99%, from the viewpoint of imparting excellent flame retardancy and excellent appearance to the polycarbonate resin composition. 0.5 mass % is more preferred, and 85 to 99.5 mass % is even more preferred.

The proportion of polytetrafluoroethylene particles contained in the composite resin particles is preferably 0.1 to 33% by mass from the viewpoint of imparting excellent flame retardancy and excellent appearance to the polycarbonate resin composition. 0.2 to 25 mass % is more preferred, and 3 to 15 mass % is even more preferred.

Such composite resin particles can be suitably produced, for example, by a method comprising the following steps.
Step 1: An aqueous dispersion of polytetrafluoroethylene particles and an aqueous dispersion of thermoplastic resin particles are mixed to prepare a mixed dispersion.
Step 2: Mix the polycarbonate resin particles and the mixed dispersion.

The details of the polytetrafluoroethylene particles, the thermoplastic resin particles, and the polycarbonate resin particles (type of resin, particle size, etc.) are as described above. Also, the mixing ratio of these may be adjusted so as to be the content in the composite resin particles of the present invention.

In step 1, for example, commercial products can be used as the aqueous dispersion of polytetrafluoroethylene particles and the aqueous dispersion of thermoplastic resin particles. The solid content in the aqueous dispersion of polytetrafluoroethylene particles is usually 20 to 65% by mass. In addition, the solid content in the aqueous dispersion of thermoplastic resin particles is usually 20 to 70% by mass.

In step 1, the aqueous dispersion of polytetrafluoroethylene particles and the aqueous dispersion of thermoplastic resin particles can be mixed using a stirrer or the like. Incidentally, when preparing a mixed dispersion of these resin particles, the pH may be adjusted using an acid or a base.

In step 2, the polycarbonate resin particles and the mixed dispersion can be mixed using a general mixer (eg, Nauta Mixer, Henschel Mixer, Butterfly Mixer, etc.), homogenizer, blender, and the like.

After step 2, it is preferable to provide a drying step. Drying means include various drying means such as hot air drying, vacuum drying, steam drying, spin drying, and suction drying.

The flame-retardant polycarbonate resin composition of the present invention can contain, in addition to the components described above, various components generally blended in flame-retardant polycarbonate resin compositions. Such components include, for example, various resins, further flame retardants, antioxidants, fluorescent whitening agents, colorants, fillers other than glass fiber, release agents, ultraviolet absorbers, antistatic agents, rubber ( elastomers), softeners, spreading agents (liquid paraffin, epoxidized soybean oil, etc.), further organometallic salts, and the like.

As various resins, known resins that are blended in polycarbonate resin compositions can be blended. Various resins include polystyrene, high impact polystyrene, ABS, AES, AAS, AS, acrylic resin, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyarylate, polysulfone, polyphenylene sulfide resin and the like. These resins may be used singly or in combination of two or more.

As the antioxidant, a known antioxidant blended in the polycarbonate resin composition can be used. Antioxidants include phosphorus antioxidants, phenolic antioxidants, and the like. Among them, hindered phenol antioxidants are preferably used, such as pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], thiodiethylene-bis[ 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] and the like. Although the amount of the antioxidant to be added is not particularly limited, it is preferably 0.005 to 1 part by mass with respect to 100 parts by mass of the polycarbonate resin.

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

As fillers other than glass fiber, known fillers blended in polycarbonate resin compositions can be used. The filler is not particularly limited and includes carbon fiber, silica, talc, mica and the like. The amount of the filler compounded is preferably 3 to 120 parts by mass with respect to 100 parts by mass of the polycarbonate resin.

As the rubber (elastomer), a known filler compounded in the polycarbonate resin composition can be used. The rubber (elastomer) is not particularly limited, and includes isobutylene/isoprene rubber, styrene/butadiene, acrylic elastomer, polyester elastomer, core-shell elastomer, and the like. The amount of the rubber (elastomer) compounded is preferably 0.05 to 20 parts by mass with respect to 100 parts by mass of the polycarbonate resin.

As the organometallic salt, a known organometallic salt blended in the polycarbonate resin composition can be used. The organic metal salt is not particularly limited, and examples thereof include aromatic sulfur compound metal salts and perfluoroalkanesulfonic acid metal salts. Alkali metals and alkaline earth metals can be mentioned as the metal of the organic sulfonate metal salt. The content of the organic metal salt is preferably 0.001 to 5 parts by mass, more preferably 0.003 to 3 parts by mass, per 100 parts by mass of the polycarbonate resin.

In the polycarbonate resin composition of the present invention, the test resin composition prepared without blending the glass fiber used in the present invention was freeze-fractured in the direction perpendicular to the flow direction, and the fracture surface was observed with a scanning electron microscope. It is preferable that the diameter of the thickest portion of the polytetrafluoroethylene (C) fibrils existing in an arbitrary field of 127 μm×95 μm is 5 μm or less.

The vertical direction (TD direction) of the resin composition refers to the direction perpendicular to the flow direction of the resin in the resin pellet. By observing the cross section perpendicular to the flow direction, the state of dispersion of polytetrafluoroethylene (D) within the pellets can be understood. Specifically, the pellets are cooled to an extremely low temperature with liquid nitrogen or the like so as not to change the dispersion state of the polytetrafluoroethylene (D), and the polycarbonate, which is the matrix resin, is brittle fractured, thereby fibrillating the polytetrafluoroethylene (D). Observe the dispersion form of tetrafluoroethylene (D). Without cooling, the polycarbonate ductile fractures and covers the polytetrafluoroethylene (D) with no observable fibrils. A relatively wide field of view of 127 μm×95 μm is observed in order to confirm the overall state. Although the number of fields to be observed is not particularly limited, it is preferable to observe, for example, three or more pellet fracture surfaces. Observing the three pellets, if there are no polytetrafluoroethylene (D) fibrils with a diameter of 5 μm or more at the thickest part, almost no aggregation of polytetrafluoroethylene (D) is observed throughout, It exhibits high flame retardancy.

When the thickness of polytetrafluoroethylene (D) is unevenly distributed, the diameter of the thickest part is used. The diameter of the thickest part of fibrils is preferably 5 μm or less, more preferably 2 μm or less. If the diameter exceeds 5 μm, streak-like lines may be formed or the hue of the surface may vary. Since the pellets have a diameter of 5 μm or less, PTFE is further fibrillated by strong shearing during injection molding in extremely thin injection-molded articles defined in the UL94 standard.

The polycarbonate resin composition of the present invention has a grade of V- when a vertical burning test (V test) of UL94 standard (combustibility test of plastic materials for equipment parts) is performed with a test piece thickness of 1.5 mm. It is preferably 0 or V-1.

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, it can be expected to have excellent flame retardancy and surface appearance.

In the flame-retardant polycarbonate resin composition of the present invention, for example, the polycarbonate resin is supplied from the first feeder (raw material supply port) into the extruder barrel, and after the resin is sufficiently melted, glass fibers are added to the second feeder (filler After feeding into the extruder barrel from the feed port), a generally available disc (e.g., kneading disc) or the like is applied to the screw used for kneading, and a plurality of such discs are used as a screw configuration by a known method. It is possible to adjust the kneading by changing the arrangement of the discs as appropriate. A pultrusion method can also be used in which the polycarbonate resin is impregnated into the fiber while the glass fiber is drawn.

The resin molded article of the present invention is obtained by molding the fiber-reinforced polycarbonate resin composition. Extrusion molding and injection molding are used as the method for molding the fiber-reinforced resin molded product of the present invention. For extrusion molding, molding such as sheet or profile extrusion using an extruder is used, and for injection molding, a mold capable of molding the molded article and a 100 to 200 mm class injection molding machine are used. A molding temperature of 260 to 320°C is desirable. Since the molded article has an excellent appearance, it can be preferably applied to housings of cameras, smartphones, and the like.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples, and can be arbitrarily changed or modified without departing from the gist of the present invention. Unless otherwise specified, "%" and "parts" in the examples indicate "% by mass" and "parts by mass", respectively, based on mass standards.

The raw materials used are as follows.
Polycarbonate resin (A):
(1) Polycarbonate resin synthesized from bisphenol A and phosgene (SD Polyca 200-3 manufactured by Sumika Polycarbonate Co., Ltd., viscosity average molecular weight 28000, hereinafter abbreviated as “PC1”)
(2) Polycarbonate resin synthesized from bisphenol A and phosgene (SD polycarbonate 200-13 manufactured by Sumika Polycarbonate Co., Ltd., viscosity average molecular weight 21000, hereinafter abbreviated as “PC2”)

Glass fiber (B):
(1) Flat cross-section glass fiber CSG 3PA-820 (manufactured by Nitto Boseki Co., Ltd., major diameter 28 μm, minor diameter 7 μm, fiber length 3 mm, urethane-based sizing agent, hereinafter abbreviated as “GF1”)
(2) Circular cross-section glass fiber CS321 (manufactured by KCC, fiber diameter 10 μm, fiber length 3 mm, epoxy-based sizing agent, hereinafter abbreviated as “GF2”)
(3) Circular cross-section glass fiber CS311 (manufactured by KCC, fiber diameter 10 μm, fiber length 3 mm, urethane-based sizing agent, hereinafter abbreviated as “GF3”)

Phosphorus antioxidant:
3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5], represented by the following formula: Undecane

アデカスタブＰＥＰ－３６（株式会社ＡＤＥＫＡ製、以下「ＰＥＰ－３６」と略記）

ADEKA STAB PEP-36 (manufactured by ADEKA Co., Ltd., hereinafter abbreviated as “PEP-36”)

Silicone flame retardant (C):
A silicone-based flame retardant (C) was produced according to a general production method. That is, depending on the molecular weight of the silicone compound component and the ratio of M units, D units, T units and Q units constituting the silicone compound, an appropriate amount of diorganodichlorosilane, monoorganotrichlorosilane and tetrachlorosilane, or partial hydration thereof dissolving the decomposition condensate in an organic solvent, adding water to hydrolyze to form a partially condensed silicone compound, and further adding triorganochlorosilane to react to terminate the polymerization; After that, the solvent was separated by distillation or the like.
The structural properties of the obtained silicone are as follows.
(C-1) Silicone compound 1 (hereinafter abbreviated as “SiIR1”)
- Ratio of D/T/Q units in main chain structure: 40/60/0 (molar ratio)
・Percentage of phenyl groups in all organic functional groups (*): 80 mol%
・Terminal group: methyl group only ・Weight average molecular weight (**): 10000
(C-2) Silicone compound 2 (hereinafter abbreviated as “SiIR2”)
- Ratio of D/T/Q units in main chain structure: 40/60/0 (molar ratio)
・Percentage of phenyl groups in all organic functional groups (*): 60 mol%
・Terminal group: methyl group only ・Weight average molecular weight (**): 65000
*: In the silicone containing T units, the phenyl group is first contained in the T unit, and in the remaining cases, it is contained in the D unit. When a phenyl group is attached to the D unit, one attached is preferred, and two phenyl groups are attached when the phenyl group remains. Except for terminal groups, the organic functional groups are all methyl groups, except for phenyl groups.
**: Weight average molecular weight is two significant digits.

Phosphate flame retardant:
Resorcinol bis-dixylenyl phosphate, PX-200 (manufactured by Daihachi Chemical Co., Ltd., hereinafter abbreviated as “PIR”)

Polytetrafluoroethylene (D):
NEOFLON FA500 (manufactured by Daikin Industries, Ltd. (hereinafter abbreviated as “PTFE1”)

Release agent:
Bee's wax (hereinafter abbreviated as "WAX")

Production Example 1 (Production of PTFE Composite Particles)
Polytetrafluoroethylene particle aqueous dispersion (primary particle diameter 0.28 μm: 31JR manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) and styrene-acrylonitrile copolymer particle aqueous dispersion (primary particle diameter 0.05 to 1 μm: Japan A & L Co., Ltd.) K-1158) were 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 neutralization liquid mixture (solid content: 0.46 parts by mass) was added to 4 parts by mass of powder of polycarbonate resin particles (primary particle size: 1 mm, bulk density: 0.2 g/cm3). Next, the mixture was heated to 80° C., stirred for 0.5 hours using a super mixer, and dried to produce composite resin particles (hereinafter abbreviated as “G1”). The mass ratio of the PC resin particles, PTFE particles and SAN particles in the composite resin particles was 89.0:6.5:6.5. Moreover, the obtained composite resin particles had an average particle diameter of 5 mm or less as a result of measurement by the method described above.

(Measurement of average particle size of PTFE composite particles)
50 ml of methylene chloride was added to 1 g of the PTFE composite particles and left at 23° C. for 3 hours. Next, the resulting solution was stirred with a stirrer for 20 minutes, and the major and minor diameters of 100 PTFE particles remaining undissolved were measured. was taken as the average particle size of the PTFE particles. As a result, the average particle diameter of the composite particles was 70 μm. The minimum value of the minor axis was 9 μm, and the maximum value of the major axis was 264 μm.

Examples 1-14 and Comparative Examples 1-4
The above-mentioned various compounding components are kneaded at a melting temperature of 300 ° C. using a twin-screw extruder (TEM-37SS manufactured by Toshiba Machine Co., Ltd.) at the compounding ratio shown in Table 1 to obtain a flame-retardant polycarbonate resin composition. rice field. Flame-retardant polycarbonate resin is prepared by supplying ingredients other than glass fiber from the first feeder (raw material supply port) into the extruder barrel, and after sufficiently melting the resin composition, the glass fiber is fed into the second feeder (filler supply). After feeding into the extruder barrel from the port), kneading was carried out to obtain flame-retardant polycarbonate resin composition pellets.

<Fibril diameter (maximum width in minor axis direction)>
Flame-retardant polycarbonate resin composition pellets (for testing) were prepared in the same manner as in Example 1, except that the glass fiber was not blended. After notching the obtained pellets, they were frozen with liquid nitrogen and fractured in a direction perpendicular to the direction of flow. The fracture surface was observed with a scanning electron microscope, and the diameter of the thickest part of the polytetrafluoroethylene (D) fibrils present in an arbitrary field of 127 μm × 95 μm (maximum width in the minor axis direction) exceeded 5 μm. The number and number of fibrils larger than 2 μm were counted. A total of three pellets were measured and evaluated according to the following criteria. These evaluation results are shown in Table 1. In the fibrils exposed on the pellet fracture surface, the maximum width in the short axis direction of the fibril cross section was regarded as the fibril diameter.
◎: One or less fibrils exceeding 2 μm ○: Two or more fibrils exceeding 2 μm, but one or less fibrils exceeding 5 μm ×: Two or more fibrils exceeding 5 μm

<Flame Retardant>
After drying the flame-retardant polycarbonate resin composition pellets obtained at the blending ratio shown in Table 1 at 120°C for 4 hours, injection molding was performed using an injection molding machine (ROBOSHOT S2000i100A manufactured by Fanuc Corporation) at a set temperature of 260°C. A test piece for flame retardancy evaluation (125×13×1.5 mm) was prepared at a pressure of 180 MPa.

The resulting test piece is left in a constant temperature room at a temperature of 23 ° C. and a humidity of 50% for 48 hours, and is flame-retardant in accordance with the UL94 test (combustibility test of plastic materials for parts of equipment) specified by Underwriters Laboratories. Flammability was evaluated. UL94V is a method for evaluating flame retardancy from afterflame time and drip properties after 10 seconds of indirect flame from a burner on a predetermined test piece held vertically, and is divided into the following classes.
V-0 (◎) V-1 (○) V-2 (△)
Afterflame time of each sample 10 seconds or less 30 seconds or less 30 seconds or less Total afterflame time of 5 samples 50 seconds or less 250 seconds or less 250 seconds or less Ignition of cotton by drip None None Yes "(No Rating) (x) is displayed.

The afterflame time is the length of time that the test piece continues to burn after the ignition source is removed, and the ignition of cotton by drip means that the marking cotton 300 mm below the lower end of the test piece is removed from the test piece. is ignited by drips of

<Flexural modulus>
After drying the flame-retardant polycarbonate resin composition pellets obtained above at 120 ° C. for 4 hours, an injection molding machine (manufactured by Fanuc, ROBOSHOT S2000i100B) was used at a set temperature of 300 ° C. and an injection pressure of 80 MPa according to the ISO test method. A test piece having a thickness of 4 mm was prepared in accordance with No. 1, and the flexural modulus (rigidity) of the obtained test piece was measured according to ISO 178 and evaluated according to the following criteria. These evaluation results are shown in Table 1.
◎: bending elastic modulus is 10 GPa or more ○: bending elastic modulus is 6 GPa or more and less than 10 GPa ×: bending elastic modulus is less than 6 GPa

<Charpy impact strength>
After drying the flame-retardant polycarbonate resin composition pellets obtained above at 120 ° C. for 4 hours, an injection molding machine (manufactured by Fanuc, ROBOSHOT S2000i100B) was used at a set temperature of 300 ° C. and an injection pressure of 80 MPa according to the ISO test method. A test piece with a thickness of 4 mm was prepared according to. Using the obtained test piece, the notched Charpy impact strength was measured according to ISO179-1 and evaluated according to the following criteria. These evaluation results are shown in Table 1.
◎: Impact strength of 15 kJ/m ² or more ○: Impact strength of 10 kJ/m ² or more and less than 15 kJ/m ² ×: Impact strength of less than 10 kJ/m ²

<Appearance of molded product>
Regarding the test piece for which the flexural modulus (rigidity) was measured, the roughness of the surface of the molded product due to floating of the glass fiber was visually observed and evaluated according to the following criteria. These evaluation results are shown in Table 1.
◎: No roughness on the surface of the molded product due to floating of the glass fiber ○: Only slight roughness on the surface of the molded product due to floating of the glass fiber ×: A lot of roughness on the surface of the molded product due to the floating of the glass fiber

The flame-retardant polycarbonate resin composition of the present invention does not impair the excellent mechanical strength and rigidity of the glass fiber-reinforced polycarbonate resin composition, and is excellent in flame retardancy and appearance of molded products. Extremely valuable. For example, it can be used as a substitute for metal products used for thin housings and internal chassis used in electrical and electronic equipment, and can reduce the weight of products. In addition, when an external force is applied to a molded article obtained from such a resin composition, the molded article may flex, causing damage to the electronic components housed inside the molded article. effectively suppressed.

Claims (7)

0.5 to 8 parts by mass of a silicone flame retardant (C) , polytetra At least one ( E) thermoplastic resin selected from the group consisting of fluoroethylene (D ), styrene-acrylonitrile copolymer, polymethacrylic styrene, polyester, polyester elastomer, polyamide, and ethylene vinyl acetate polymer, phosphorus containing an acid ester flame retardant, a phosphorus antioxidant, and a release agent,
The glass fiber (B) has a flattened cross-section with an average long diameter of 10 to 50 μm in the fiber cross section and an average ratio of the long diameter to the short diameter of 2 to 8,
Among the organic functional groups possessed by the silicone flame retardant (C), the proportion of aromatic groups is 40 to 95 mol%,
A method for producing a flame-retardant polycarbonate resin composition, wherein the content of polytetrafluoroethylene (D) in the composition is 0.1 to 1.0% by mass,
A step of mixing an aqueous dispersion of polytetrafluoroethylene particles (D) with an aqueous dispersion of thermoplastic resin particles (E) having an average particle size of 5 μm or less to prepare a mixed dispersion;
A step of mixing the obtained mixed dispersion and polycarbonate resin particles to obtain composite resin particles, and
The obtained composite resin particles, polycarbonate resin (A), glass fiber (B), silicone flame retardant (C), phosphate ester flame retardant, phosphorus antioxidant, and release agent are kneaded. process
A method for producing a flame-retardant polycarbonate resin composition comprising: 2. The method for producing a flame-retardant polycarbonate resin composition according to claim 1, wherein the glass fibers (B) are treated with an epoxy-based sizing agent or a urethane-based sizing agent and have an average cross-sectional diameter of 6 to 20 μm. The method for producing a flame-retardant polycarbonate resin composition according to claim 1 or 2, wherein the content of the thermoplastic resin (E) is 0.005 to 5% by mass in the flame-retardant polycarbonate resin composition. An arbitrary 127 μm × 95 μm field of view of a fracture surface obtained by freeze-fracture in the direction perpendicular to the flow direction of the resin composition for testing prepared without blending glass fibers in the resin composition and observed with a scanning electron microscope. The flame-retardant polycarbonate resin composition according to any one of claims 1 to 3, wherein the diameter of the thickest part of the polytetrafluoroethylene (D) fibrils present in the flame-retardant polycarbonate resin composition is 5 μm or less . manufacturing method . 5. The method for producing a flame-retardant polycarbonate resin composition according to claim 4, wherein the diameter of the thickest portion of the polytetrafluoroethylene (D) fibrils is 2 μm or less. The method for producing a flame-retardant polycarbonate resin composition according to any one of claims 1 to 5, wherein the polytetrafluoroethylene (D) has an average particle size of 200 µm or less. A step of producing a flame-retardant polycarbonate resin composition by the production method according to any one of claims 1 to 6, and a step of molding the obtained flame-retardant polycarbonate resin composition. manufacturing method .