Pellets, molded articles, and pellet manufacturing method

Abstract

To provide: a pellet with which it is possible to provide a molded article including a polycarbonate resin, recycled carbon fibers and an inorganic filler and having mechanical strength close to that obtained by blending the same amount of a virgin carbon fiber; a molded article; and a method for manufacturing a pellet.SOLUTION: A pellet is formed of a composition including 5-40 pts.mass of recycled carbon fibers that are a heated product of a carbon fiber-reinforced resin, and 5-40 pts.mass of an inorganic filler relative to 100 pts.mass of a polycarbonate resin whose amount of terminal hydroxyl group is 150-800 ppm.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to pellets, molded articles, and methods for producing pellets, and more particularly to pellets that effectively utilize recycled carbon fibers. [Background technology]

[0002] Polycarbonate resins are widely used in many fields as resins with excellent heat resistance, impact resistance, transparency, etc. In particular, polycarbonate resin compositions reinforced with inorganic fillers such as glass fibers or carbon fibers exhibit various excellent properties such as dimensional stability, mechanical strength, heat resistance, and electrical properties, and are therefore widely used in industrial fields such as cameras, office automation equipment, and electrical and electronic parts (Patent Document 1). On the other hand, from the viewpoint of making effective use of limited resources, recycling of carbon fibers has been considered. Known examples of recycled carbon fibers include those described in Patent Document 2. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-063812 [Patent Document 2] International Publication No. 2018 / 212016 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when recycled carbon fibers are blended into polycarbonate resin, the mechanical strength is inferior to that of a composition containing newly produced carbon fibers, i.e., virgin carbon fibers. If the mechanical strength of a composition containing polycarbonate resin and recycled carbon fibers can be made close to that of a composition containing virgin carbon fibers, an improvement in the recycling rate of carbon fibers can be expected. On the other hand, in recent years, research has been conducted into blending both recycled carbon fiber and other inorganic fillers into polycarbonate resins. Even in such materials, it is desirable to achieve mechanical strength close to that of materials blended with virgin carbon fiber. The present invention aims to solve the above problems and to provide pellets, a molded product, and a method for producing pellets that can provide a molded product containing polycarbonate resin, recycled carbon fiber, and an inorganic filler, which has mechanical strength similar to that of a molded product containing the same amount of virgin carbon fiber. [Means for solving the problem]

[0005] In view of the above problems, the present inventors have conducted research and have found that the above problems can be solved by using a polycarbonate resin having a predetermined terminal group concentration. Specifically, the above problems were solved by the following means. <1> Pellets formed from a composition containing 100 parts by mass of polycarbonate resin with a terminal hydroxyl group content of 150 to 800 ppm, 5 to 40 parts by mass of recycled carbon fiber, which is a heated carbon fiber reinforced resin, and 5 to 40 parts by mass of an inorganic filler. <2> The flexural strength measured in accordance with ISO 178 using an ISO multipurpose test piece molded from the composition has a retention rate of 88% or more compared to the flexural strength measured in accordance with ISO 178 using an ISO multipurpose test piece molded from a composition in which the polycarbonate resin contained in the composition is replaced with a polycarbonate resin having an equivalent amount of terminal hydroxyl groups of 140 ppm and the recycled carbon fiber is replaced with virgin carbon fiber having an equivalent amount of carbon fiber. <1> The pellets described in <3> The polycarbonate resin comprises a recycled polycarbonate resin. <1> or <2> The pellets described in <4> The inorganic filler includes a glass filler. <1> ~ <3> 10. The pellet according to any one of claims 1 to 9. <5> Further, the composition contains 0.5 to 30 parts by mass of a flow modifier relative to 100 parts by mass of the polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. <1> ~ <4> 10. The pellet according to any one of claims 1 to 9. <6> Further, the composition contains 0.1 to 10 parts by mass of at least one selected from a release agent and carbon black in total relative to 100 parts by mass of the polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. <1> ~ <5> 10. The pellet according to any one of claims 1 to 9. <7> <1> ~ <6> A molded article formed from the pellets according to any one of claims 1 to 4. <8> A method for producing pellets, comprising: feeding 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm, 5 to 40 parts by mass of recycled carbon fiber which is a heated carbon fiber reinforced resin, and 5 to 40 parts by mass of an inorganic filler into an extruder, and melt-kneading the mixture. [Effects of the Invention]

[0006] The present invention makes it possible to provide a molded article containing polycarbonate resin, recycled carbon fiber, and inorganic filler, which has mechanical strength close to that of a molded article containing the same amount of virgin carbon fiber. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, an embodiment for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the present embodiment is an example for explaining the present invention, and the present invention is not limited to only this embodiment. In this specification, the symbol "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit. In this specification, various physical properties and characteristic values ​​are those at 23°C unless otherwise specified. In this specification, ppm means ppm by mass. If the measurement methods, etc. described in the standards shown in this specification vary from year to year, they will be based on the standards as of January 1, 2021, unless otherwise stated.

[0008] The pellets of this embodiment are formed from a composition containing 100 parts by mass of polycarbonate resin with a terminal hydroxyl group content of 150 to 800 ppm, 5 to 40 parts by mass of recycled carbon fiber (a heated carbon fiber reinforced resin), and 5 to 40 parts by mass of inorganic filler. The use of such pellets makes it possible to provide a molded article containing polycarbonate resin, recycled carbon fiber, and inorganic filler, which has mechanical strength similar to that of a molded article containing the same amount of virgin carbon fiber. This is presumably because the terminal hydroxyl group content of the polycarbonate resin is 150 to 800 ppm, which improves adhesion between the carbon fiber surface and the polycarbonate resin, thereby improving mechanical strength. The present invention will be described in detail below.

[0009] <Polycarbonate resin> The composition used in this embodiment contains a polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. The type of polycarbonate resin is not particularly limited as long as the terminal hydroxyl group content is 150 to 800 ppm, but typically, the main component is preferably an aromatic polycarbonate resin, more preferably a bisphenol polycarbonate resin, and even more preferably a bisphenol A polycarbonate resin. Here, the main component refers to a component that accounts for 80% by mass or more (preferably 90% by mass or more, more preferably 95% by mass or more) of the polycarbonate resin contained in the composition.

[0010] The polycarbonate resin may be a polycarbonate resin obtained by melt polymerization or an interfacial polymerization, preferably a polycarbonate resin obtained by melt polymerization, or may be a mixture of a polycarbonate resin obtained by melt polymerization and a polycarbonate resin obtained by interfacial polymerization. More specifically, the polycarbonate resin used in this embodiment is preferably an aromatic polycarbonate resin, which can be produced, for example, by a melt transesterification method using an aromatic dihydroxy compound and a carbonic acid diester as raw materials.

[0011] Examples of aromatic dihydroxy compounds include bis(4-hydroxydiphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3-t-butylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 4,4-bis(4-hydroxyphenyl)heptane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4'-dihydroxybiphenyl, 3,3',5,5'-tetramethyl-4,4'-dihydroxybiphenyl, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)ether, and bis(4-hydroxyphenyl)ketone. These aromatic dihydroxy compounds can be used alone or in combination. Of these, 2,2-bis(4-hydroxyphenyl)propane is preferred.

[0012] Examples of the carbonic acid diester include diphenyl carbonate, substituted diphenyl carbonates such as ditolyl carbonate, and dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, and di-t-butyl carbonate. These carbonic acid diesters can be used alone or in combination of two or more. Among these, diphenyl carbonate and substituted diphenyl carbonates are preferred. Furthermore, the above-mentioned carbonic acid diester may be substituted with a dicarboxylic acid or a dicarboxylic acid ester, preferably in an amount of 50 mol % or less, more preferably 30 mol % or less. Typical dicarboxylic acids or dicarboxylic acid esters include terephthalic acid, isophthalic acid, diphenyl terephthalate, and diphenyl isophthalate. When substituted with such a dicarboxylic acid or dicarboxylic acid ester, a polyester carbonate resin is obtained.

[0013] These carbonic acid diesters (including the above-mentioned substituted dicarboxylic acids or esters of dicarboxylic acids) are usually used in excess relative to the aromatic dihydroxy compound, i.e., in a molar amount within the range of 1.001 to 1.3 times, preferably 1.01 to 1.2 times, the amount of the aromatic dihydroxy compound.

[0014] The polycarbonate resin used in this embodiment has a terminal hydroxyl group content of 150 to 800 ppm. By using a polycarbonate resin with a terminal hydroxyl group content of 150 to 800 ppm, it is possible to improve adhesion to the recycled carbon fiber surface and maintain a high mechanical strength compared to when a polycarbonate resin with a terminal hydroxyl group content of less than 150 ppm is blended. In particular, it is possible to maintain a high bending strength. The amount of terminal hydroxyl groups is preferably 200 ppm or more, more preferably 250 ppm or more, even more preferably 300 ppm or more, even more preferably 350 ppm or more, even more preferably 400 ppm or more, even more preferably 450 ppm or more, and particularly more preferably 500 ppm or more. By setting the amount to the lower limit or more, the adhesion between the carbon fiber surface and the polycarbonate resin is improved, the transesterification reaction rate is increased, making it easier to obtain a polycarbonate resin having the desired molecular weight, and the amount of carbonate ester remaining in the polycarbonate resin can be reduced, which tends to more effectively suppress odor during molding or when a molded product is obtained. Furthermore, the amount of terminal hydroxyl groups is preferably 750 ppm or less, more preferably 700 ppm or less, even more preferably 650 ppm or less, even more preferably 640 ppm or less, and may be 610 ppm or less. By setting the amount to the upper limit or less, the thermal stability of the polycarbonate resin tends to be further improved. The amount of terminal hydroxyl groups is measured according to the description in the Examples section below. When the composition used in this embodiment contains two or more types of polycarbonate resins, the amount of terminal hydroxyl groups is the amount of the polycarbonate resin mixture.

[0015] In addition to the above, details of the polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm can be found in JP-A-2003-026911, the contents of which are incorporated herein by reference.

[0016] The polycarbonate resin used in this embodiment (when two or more types are contained, a mixture of polycarbonate resins) also has a melt volume rate (MVR) of 1 cm 3 / 10 min or more is preferable, and 5 cm 3 / 10min or more is more preferable, and 8cm 3 / 10 min or more is more preferable, and 3 / 10 min or less is preferable, and 30 cm 3By setting the value to be equal to or greater than the lower limit, it is particularly preferable that the 3 By setting the MVR to 10 min or more, high flow and moldability tend to be achieved, while by setting the MVR to the upper limit or less, high impact resistance and heat resistance tend to be maintained. MVR is measured in accordance with JIS K 7210. The viscosity average molecular weight of the polycarbonate resin used in this embodiment (a mixture of polycarbonate resins when two or more types are included) is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 14,000 or more, and is preferably 50,000 or less, and more preferably 24,000. By using a resin having a viscosity average molecular weight of 5,000 or more, the mechanical strength of the resulting molded article tends to be improved. Furthermore, by using a resin having a viscosity average molecular weight of 50,000 or less, the fluidity of the molten pellets tends to be improved, and moldability tends to be further improved. The viscosity average molecular weight of the polycarbonate resin is the viscosity average molecular weight [Mv] calculated from the solution viscosity measured at 25°C using methylene chloride as a solvent.

[0017] The polycarbonate resin used in this embodiment may be a recycled polycarbonate resin. By using a recycled polycarbonate resin, it is possible to provide pellets with reduced environmental impact. The recycled polycarbonate resin may be derived from bottles, discs, pachinko machines, sheets, semiconductor transport containers, etc. The recycled polycarbonate resin is preferably a recycled aromatic polycarbonate resin.

[0018] In the composition used in this embodiment, the content of the polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm is preferably 55 to 95 mass %. The composition used in the present embodiment may contain only one type of polycarbonate resin, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0019] <Recycled carbon fiber> The composition used in this embodiment contains 5 to 40 parts by mass of recycled carbon fiber, which is a heated carbon fiber reinforced resin, per 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. Blending such recycled carbon fiber with polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm makes it possible to maintain high mechanical strength comparable to that of compositions blended with virgin carbon fiber. Recycled carbon fiber typically contains substantially no treatment agents, such as surface treatment agents or sizing agents, making it difficult to sufficiently melt-knead it with polycarbonate resin. However, in this embodiment, by using a heated carbon fiber reinforced resin as the recycled carbon fiber, it is presumed that the charcoal-derived residue from the resin acts as a treatment agent for the carbon fiber, enabling stable melt-kneading with the polycarbonate resin. Here, recycled carbon fiber refers to, for example, carbon fiber recovered from used carbon fiber reinforced resin (aircraft, vehicles, electrical and electronic devices, etc.) or carbon fiber recovered from scraps of intermediate products (prepregs) of carbon fiber reinforced resin generated during the manufacturing process of carbon fiber reinforced resin. In contrast, virgin carbon fiber is new carbon fiber that is not recycled carbon fiber, such as that generally sold as carbon fiber.

[0020] In this embodiment, heated carbon fiber reinforced resin is used as the recycled carbon fiber. When the carbon fiber reinforced resin is heated, the resin becomes charcoal, which exists on the surface of the carbon fiber. The carbon fiber reinforced resin in this embodiment includes carbon fibers and a matrix resin. The type of carbon fiber is not particularly limited, but PAN-based carbon fiber is preferred. The matrix resin may be a thermosetting resin or a thermoplastic resin. The thermosetting resin may be uncured or cured. Examples of thermosetting resins include epoxy resins, unsaturated polyester resins, vinyl ester resins, phenolic resins, cyanate resins, and polyimide resins. Examples of thermoplastic resins include polyamides, polyolefins, polyesters, polycarbonates, acrylic resins, acrylonitrile-butadiene-styrene copolymers, polyether ether ketones, and polyphenylene sulfides. The matrix resin may contain additives as needed, such as a curing agent, a curing aid, an internal mold release agent, an antioxidant, a light stabilizer, an ultraviolet absorber, and a colorant. The heating temperature of the carbon fiber reinforced resin is not particularly limited as long as it is a temperature at which the matrix resin is carbonized, but is preferably 300 to 700°C, more preferably 400 to 700°C, and even more preferably 500 to 700°C. For details of the recycled carbon fiber, which is a heated carbon fiber reinforced resin, please refer to the description in International Publication No. 2018 / 212016, the contents of which are incorporated herein by reference.

[0021] The content of resin residue in the recycled carbon fiber is preferably 5% by mass or more, more preferably 10% by mass or more, and is preferably 20% by mass or less, and more preferably 15% by mass or less.

[0022] As described above, recycled carbon fibers usually have substantially no treatment agents (sizing agents, sizing agents, surface treatment agents, etc.) on their surfaces. "Substantially no treatment agents" means that the amount of treatment agent is, for example, less than 1.0 mass%, further less than 0.1 mass%, particularly less than 0.01 mass%, and more particularly less than 0.001 mass% of the total amount of recycled carbon fibers.

[0023] The number average fiber diameter of the recycled carbon fiber is preferably 3 μm or more, and more preferably 4 μm or more. Also, it is preferably 10 μm or less, and more preferably 8 μm or less. When the number average fiber diameter of the recycled carbon fiber is within this range, pellets with improved mechanical properties, particularly strength and elastic modulus, can be easily obtained.

[0024] In the composition used in this embodiment, the content of recycled carbon fiber, which is a heated product of carbon fiber reinforced resin, is 5 parts by mass or more, preferably 8 parts by mass or more, and may be 10 parts by mass or more, 13 parts by mass or more, or 15 parts by mass or more, per 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. By setting the content at or above the lower limit, a composition with superior mechanical strength tends to be obtained. Furthermore, the content of recycled carbon fiber is 40 parts by mass or less, preferably 35 parts by mass or less, and may be 30 parts by mass or less, 25 parts by mass or less, or 20 parts by mass or less, per 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. By setting the content at or below the upper limit, a composition with superior mechanical strength and moldability tends to be obtained. Furthermore, the composition used in this embodiment preferably contains recycled carbon fiber, which is a heated carbon fiber reinforced resin, in a proportion of 1% by mass or more, more preferably 2% by mass or more, and even more preferably 5% by mass or more, in terms of the actual amount of carbon fiber in the composition, and preferably contains it in a proportion of 30% by mass or less, and more preferably 25% by mass or less. The composition used in this embodiment may contain only one type of recycled carbon fiber, which is a heated carbon fiber reinforced resin, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0025] In the composition used in this embodiment, the total amount of the polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm, the recycled carbon fiber, and the non-metal salt flame retardant preferably accounts for 90% by mass or more of the composition, more preferably 95% by mass or more, and even more preferably 97% by mass or more, with the upper limit of the total amount being 100% by mass.

[0026] The composition used in this embodiment may or may not contain virgin carbon fiber. One example of the composition used in this embodiment is one in which the virgin carbon fiber accounts for 5 to 50% by mass (preferably 5 to 30% by mass) of the recycled carbon fiber content. Another example of the composition used in this embodiment is one in which the virgin carbon fiber accounts for less than 5% by mass (preferably less than 3% by mass, more preferably less than 1% by mass) of the recycled carbon fiber content.

[0027] <Inorganic fillers> The composition used in this embodiment contains 5 to 40 parts by mass of an inorganic filler relative to 100 parts by mass of a polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. The inorganic filler in this embodiment excludes carbon fiber (recycled carbon fiber and virgin carbon fiber).

[0028] The inorganic filler may be any of an acicular inorganic filler, a fibrous inorganic filler, and a plate-like inorganic filler. The acicular inorganic filler is an inorganic filler having a whisker-like, columnar, or other shape, and examples thereof include wollastonite and boehmite. The fibrous inorganic filler refers to a thin, long fibrous inorganic filler, and examples thereof include glass fiber, metal fiber, and ceramic fiber. Examples of the shape of the fibrous inorganic filler include chopped strands and milled fibers. The plate-like inorganic filler is an inorganic filler having a flake-like, scaly, or other shape, and examples thereof include talc, mica, and glass flakes.

[0029] In this embodiment, the inorganic filler is preferably a glass filler, and examples thereof include glass fiber (including chopped strands), milled fiber, glass flakes, glass beads, and glass balloons, with glass fiber, milled fiber, and glass flakes being preferred. The raw glass composition is preferably alkali-free, and examples thereof include E glass, C glass, S glass, and R glass, but E glass is preferably used in the present invention.

[0030] The cross-sectional shape of the glass fiber may be a general circular shape or various irregular cross-sectional shapes, such as circular fibers stacked in parallel. The number-average fiber diameter of such glass fibers is preferably 1 to 25 μm, more preferably 5 to 17 μm. The number-average fiber length is preferably 300 μm to 1 mm.

[0031] The glass flakes are, for example, scale-like flakes having a thickness of 1 to 20 μm and a side length of 0.05 to 1.0 mm. The thickness and length are number average values.

[0032] The glass filler is preferably surface-treated with a known surface treatment agent, such as a silane coupling agent, methylhydrogensiloxane, titanate coupling agent, or aluminate coupling agent, from the viewpoint of improving mechanical strength.

[0033] Milled fibers are, for example, glass fibers milled to lengths of approximately 10 to 300 μm. The milled fibers used in this embodiment preferably have a number-average fiber length of 15 μm or more, more preferably 20 μm or more, even more preferably 40 μm or more, and even more preferably 50 μm or more. The upper limit of the number-average fiber length is preferably 200 μm or less, more preferably 150 μm or less, even more preferably 120 μm or less, and even more preferably 100 μm or less. By setting the number-average fiber length within these ranges, the resulting molded article can have a better balance between mechanical strength and appearance. The milled fibers preferably have a number-average fiber diameter of 1 μm or more, more preferably 2 μm or more, and even more preferably 3 μm or more. The upper limit of the number-average fiber diameter of the milled fibers is preferably 25 μm or less, more preferably 20 μm or less, and even more preferably 15 μm or less. By setting the number-average fiber diameter within these ranges, the resulting molded article can have a better balance between mechanical strength and appearance.

[0034] The number average fiber length, number average thickness, and number average fiber diameter of the inorganic filler can be determined by observing the length etc. of any 100 fibers using a microscope and calculating the average value.

[0035] When the composition used in this embodiment contains an inorganic filler, the content thereof is 5 parts by mass or more relative to 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm, and may be 10 parts by mass or more depending on the application, etc. By setting the content at or above the lower limit, strength and rigidity tend to be further improved. Furthermore, the upper limit of the content of the inorganic filler is 40 parts by mass or less, preferably 35 parts by mass or less, relative to 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm, and may be 20 parts by mass or less, or 10 parts by mass or less depending on the application, etc. By setting the content at or below the upper limit, moldability tends to be further improved. Furthermore, the composition used in this embodiment preferably contains an inorganic filler in a proportion of 1% by mass or more, more preferably 2% by mass or more, and even more preferably 5% by mass or more, and preferably 30% by mass or less, and more preferably 25% by mass or less. The composition used in this embodiment may contain only one type of inorganic filler, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0036] <Flame retardant> The composition used in this embodiment may or may not contain a flame retardant. The flame retardant preferably includes at least one selected from a metal salt-based flame retardant, a phosphorus-based flame retardant, and a halogen-based flame retardant.

[0037] The content of the flame retardant in the composition used in this embodiment is preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, even more preferably 0.03 parts by mass or more, even more preferably 0.04 parts by mass or more, and even more preferably 0.05 parts by mass or more, per 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. By setting the content at or above the lower limit, the flame retardancy of the resulting molded article tends to be improved, and the mechanical strength retention rate tends to be increased. Furthermore, the upper limit of the content of the non-metal salt flame retardant is preferably 35 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less, per 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. By setting the content at or below the upper limit, the appearance and mechanical strength of the resulting molded article tend to be further improved. The composition used in this embodiment may contain only one flame retardant, or may contain two or more flame retardants. When two or more flame retardants are contained, the total amount is preferably in the above range.

[0038] Next, the metal salt flame retardant will be described in detail. As the metal salt flame retardant, an organic metal salt flame retardant is preferred, and an organic alkali metal salt compound is more preferred. Examples of organic metal salt flame retardants include metal sulfonates, metal carboxylates, metal borates, and metal phosphates, with organic metal sulfonates being preferred from the standpoint of thermal stability.

[0039] Examples of metals constituting the alkali metal salt include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs), with sodium, potassium, and cesium being preferred.

[0040] Preferable examples of the alkali metal organic sulfonate include alkali metal salts of fluorine-containing aliphatic sulfonic acids and aromatic sulfonic acids. Specific examples of preferable examples include alkali metal salts of fluorine-containing aliphatic sulfonic acids having at least one C—F bond in the molecule, such as potassium perfluorobutanesulfonate, lithium perfluorobutanesulfonate, sodium perfluorobutanesulfonate, cesium perfluorobutanesulfonate, potassium trifluoromethanesulfonate, lithium trifluoromethanesulfonate, sodium trifluoromethanesulfonate, and cesium trifluoromethanesulfonate; dipotassium diphenylsulfone-3,3′-disulfonate, potassium diphenylsulfone-3-sulfonate, sodium benzenesulfonate, and sodium (poly)styrenesulfonate. and alkali metal salts of aromatic sulfonic acids having at least one aromatic group in the molecule, such as sodium paratoluenesulfonate, sodium (branched)dodecylbenzenesulfonate, sodium trichlorobenzenesulfonate, potassium benzenesulfonate, potassium styrenesulfonate, (poly)potassium styrenesulfonate, potassium paratoluenesulfonate, potassium (branched)dodecylbenzenesulfonate, potassium trichlorobenzenesulfonate, cesium benzenesulfonate, (poly)cesium styrenesulfonate, cesium paratoluenesulfonate, cesium (branched)dodecylbenzenesulfonate, and cesium trichlorobenzenesulfonate.

[0041] Among the above-mentioned examples, alkali metal salts of fluorine-containing aliphatic sulfonic acids are particularly preferred, and alkali metal salts of perfluoroalkanesulfonic acids are even more preferred. Specifically, potassium perfluorobutanesulfonate, sodium trifluoromethanesulfonate, etc. are particularly preferred.

[0042] Specific examples of fluorine-containing organic sulfonic acid alkali metal salts include Megafac F114P (trade name) manufactured by DIC Corporation, Biowet C4 (trade name) manufactured by Lanxess AG, and IHT-FR21 (trade name) manufactured by Insight High Technology AG.

[0043] When the composition used in this embodiment contains a metal salt flame retardant, the content thereof is preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, even more preferably 0.03 parts by mass or more, even more preferably 0.04 parts by mass or more, and even more preferably 0.05 parts by mass or more, per 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. By setting the content at or above the lower limit, the flame retardancy of the resulting molded article tends to be improved, and the mechanical strength retention rate tends to be increased. Furthermore, the upper limit of the content of the metal salt flame retardant is preferably 0.75 parts by mass or less, more preferably 0.50 parts by mass or less, even more preferably 0.30 parts by mass or less, and even more preferably 0.20 parts by mass or less, per 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. By setting the content at or below the upper limit, the appearance and mechanical strength of the resulting molded article tend to be further improved. The composition used in this embodiment may contain only one metal salt flame retardant, or may contain two or more metal salt flame retardants. When two or more metal salt flame retardants are contained, the total amount is preferably in the above range.

[0044] Next, the phosphorus-based flame retardant will be described in detail. Examples of phosphorus-based flame retardants include phosphate esters and / or phosphazenes.

[0045] The phosphate ester is preferably a phosphate ester compound represented by the following formula (1). [ka] (In formula (1), R 1 , R 2 , R 3 and R 4 each independently represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 20 carbon atoms which may be substituted with an alkyl group having 1 to 6 carbon atoms; p, q, r, and s each independently represent 0 or 1; k represents a number from 1 to 5; and X 1 represents an arylene group.

[0046] The phosphate ester compound represented by the formula (1) may be a mixture of compounds having different k values, and in the case of such a mixture of phosphate esters having different k values, k is the average value of the mixture. In the case of a mixture of compounds having different k values, the average k value is preferably 1 to 2, more preferably 1 to 1.5, even more preferably 1 to 1.2, and particularly preferably 1 to 1.15.

[0047] Also, X 1 represents a divalent arylene group, such as a divalent group derived from a dihydroxy compound such as resorcinol, hydroquinone, bisphenol A, 2,2'-dihydroxybiphenyl, 2,3'-dihydroxybiphenyl, 2,4'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 3,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, or 2,7-dihydroxynaphthalene. Of these, divalent groups derived from resorcinol, bisphenol A, or 3,3'-dihydroxybiphenyl are particularly preferred.

[0048] In addition, p, q, r and s in formula (1) each represent 0 or 1, with 1 being preferred. Also, R 1 , R 2 , R 3 and R 4 and respectively represent an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 20 carbon atoms which may be substituted with an alkyl group having 1 to 6 carbon atoms. Such aryl groups are preferably phenyl, cresyl, xylyl, isopropylphenyl, butylphenyl, tert-butylphenyl, di-tert-butylphenyl, or p-cumylphenyl, and more preferably phenyl, cresyl, or xylyl.

[0049] Preferred examples of the phosphate ester represented by formula (1) include phenyl resorcinol polyphosphate, cresyl resorcinol polyphosphate, phenyl cresyl resorcinol polyphosphate, xylyl resorcinol polyphosphate, phenyl-pt-butylphenyl resorcinol polyphosphate, phenyl isopropylphenyl resorcinol polyphosphate, cresyl xylyl resorcinol polyphosphate, and phenyl isopropylphenyl diisopropylphenyl resorcinol polyphosphate.

[0050] The acid value of the phosphate ester compound represented by formula (1) is preferably 0.2 mgKOH / g, more preferably 0.15 mgKOH / g or less, even more preferably 0.1 mgKOH or less, and particularly preferably 0.05 mgKOH / g or less. The lower limit of the acid value of the phosphate ester compound represented by formula (1) can be set to substantially 0 mgKOH / g.

[0051] On the other hand, phosphazene is an organic compound having a -P=N- bond in the molecule, and is preferably at least one compound selected from the group consisting of phosphazene compounds represented by formula (2), phosphazene compounds represented by formula (3), and crosslinked phosphazene compounds obtained by crosslinking at least one phosphazene compound selected from the group consisting of formulas (2) and (3) with a crosslinking group. As the crosslinked phosphazene compound, one crosslinked with a crosslinking group represented by the following formula (4) is preferred from the viewpoint of flame retardancy. Phosphazene has a high flame retardant effect, and when used in combination with carbon black (described later), it can exhibit excellent flame retardancy, thereby suppressing the reduction in mechanical strength and gas generation that can occur when a flame retardant is added.

[0052] [ka] (In formula (2), m is an integer of 3 to 25, and R 1 may be the same or different and represent an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 20 carbon atoms which may be substituted with an alkyl group having 1 to 6 carbon atoms.

[0053] [ka] (In formula (3), n is an integer of 3 to 10,000, and X is -N=P(OR 1 )3 groups or N=P(O)OR 1 represents a group, and Y represents a -P(OR 1 )4 groups or P(O)(OR 1 )2 groups. R 1 may be the same or different and represent an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 20 carbon atoms which may be substituted with an alkyl group having 1 to 6 carbon atoms.

[0054] [ka] (In formula (4), A is —C(CH)—, —SO—, —S—, or O—, and l is 0 or 1.)

[0055] Examples of the phosphazene compounds represented by formulas (2) and (3) include cyclic and / or chain C phosphazenes such as phenoxyphosphazene, (poly)tolyloxyphosphazene (e.g., o-tolyloxyphosphazene, m-tolyloxyphosphazene, p-tolyloxyphosphazene, o,m-tolyloxyphosphazene, o,p-tolyloxyphosphazene, m,p-tolyloxyphosphazene, o,m,p-tolyloxyphosphazene, etc.), and (poly)xylyloxyphosphazene. 1-6 Alkyl C 6-20 Cyclic and / or chain C phosphazenes such as aryloxyphosphazenes, (poly)phenoxytolyloxyphosphazenes (e.g., phenoxy o-tolyloxyphosphazene, phenoxy m-tolyloxyphosphazene, phenoxy p-tolyloxyphosphazene, phenoxy o,m-tolyloxyphosphazene, phenoxy o,p-tolyloxyphosphazene, phenoxy m,p-tolyloxyphosphazene, phenoxy o,m,p-tolyloxyphosphazene, etc.), (poly)phenoxyxylyloxyphosphazene, and (poly)phenoxytolyloxyxylyloxyphosphazene. 6-20 Aryl C 1-10 Alkyl C 6-20 Examples include aryloxyphosphazenes, and preferred are cyclic and / or chain phenoxyphosphazenes, cyclic and / or chain C 1-3 Alkyl C 6-20 Aryloxyphosphazene, C 6-20 Aryloxy C 1-3 Alkyl C 6-20 Aryloxyphosphazenes (for example, cyclic and / or chain tolyloxyphosphazenes, cyclic and / or chain phenoxytolylphenoxyphosphazenes, etc.).

[0056] The compound represented by formula (2) includes R 1Cyclic phenoxyphosphazenes in which m is a phenyl group are particularly preferred. Examples of such cyclic phenoxyphosphazene compounds include compounds such as phenoxycyclotriphosphazene, octaphenoxycyclotetraphosphazene, and decafenoxycyclopentaphosphazene, which are obtained by isolating cyclic chlorophosphazenes such as hexachlorocyclotriphosphazene, octachlorocyclotetraphosphazene, and decachlorocyclopentaphosphazene from a mixture of cyclic and linear chlorophosphazenes obtained by reacting ammonium chloride and phosphorus pentachloride at a temperature of 120 to 130°C, and then substituting them with phenoxy groups. Furthermore, the cyclic phenoxyphosphazene compound is preferably a compound in which m in formula (2) is 3 to 5, or may be a mixture of compounds with different m's. Among these, a mixture of compounds in which m=3 accounts for 50% by mass or more, m=4 accounts for 10 to 40% by mass, and m=5 or more accounts for 30% by mass or less in total is preferred.

[0057] The phosphazene compound represented by formula (3) includes R 1 is a phenyl group. Examples of such chain phenoxyphosphazene compounds include compounds obtained by ring-opening polymerization of hexachlorocyclotriphosphazene obtained by the above method at a temperature of 220 to 250°C, and substituting the resulting linear dichlorophosphazene having a degree of polymerization of 3 to 10,000 with a phenoxy group. In the linear phenoxyphosphazene compound, n in formula (3) is preferably 3 to 1,000, more preferably 3 to 100, and even more preferably 3 to 25.

[0058] Examples of the crosslinked phenoxyphosphazene compound include compounds having a crosslinked structure of a 4,4'-diphenylene group, such as a compound having a crosslinked structure of 4,4'-sulfonyldiphenylene (bisphenol S residue), a compound having a crosslinked structure of a 2,2-(4,4'-diphenylene)isopropylidene group, a compound having a crosslinked structure of a 4,4'-oxydiphenylene group, and a compound having a crosslinked structure of a 4,4'-thiodiphenylene group. The crosslinked phosphazene compound is a compound represented by the formula (2) 1 a bridged phenoxyphosphazene compound in which a cyclic phenoxyphosphazene compound in which R is a phenyl group is bridged by a bridge group represented by the above formula (4); or 1 A bridged phenoxyphosphazene compound obtained by crosslinking a chain phenoxyphosphazene compound in which R is a phenyl group with a crosslinking group represented by the above formula (4) is preferred from the viewpoint of flame retardancy, and a bridged phenoxyphosphazene compound obtained by crosslinking a cyclic phenoxyphosphazene compound with a crosslinking group represented by the above formula (4) is more preferred. The content of phenylene groups in the bridged phenoxyphosphazene compound is usually 50 to 99.9%, preferably 70 to 90%, based on the total number of phenyl groups and phenylene groups in the cyclic phosphazene compound represented by formula (2) and / or the chain phenoxyphosphazene compound represented by formula (3). It is particularly preferable that the bridged phenoxyphosphazene compound is a compound having no free hydroxyl groups in its molecule.

[0059] The phosphazene in this embodiment is preferably a cyclic phenoxyphosphazene compound represented by formula (2) from the viewpoints of flame retardancy and mechanical properties.

[0060] In particular, when the composition used in this embodiment contains a phosphorus-based flame retardant, the content thereof is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, per 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. By setting the content at or above the lower limit, the flame retardancy of the resulting molded article tends to be enhanced, and the mechanical strength retention rate tends to be enhanced. Furthermore, the upper limit of the content of the phosphorus-based flame retardant is preferably 35 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less, per 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. By setting the content at or below the upper limit, the appearance and mechanical strength of the resulting molded article tend to be further improved. The composition used in this embodiment may contain only one phosphorus-based flame retardant, or may contain two or more phosphorus-based flame retardants. When two or more phosphorus-based flame retardants are contained, the total amount is preferably in the above range.

[0061] Next, the halogen-based flame retardant will be described in detail. Examples of halogen-based flame retardants include flame retardants containing bromine (bromine-based flame retardants). The type of brominated flame retardant is not particularly limited, but brominated phthalimide, brominated poly(meth)acrylate, brominated polycarbonate, brominated epoxy, and brominated polystyrene are preferred, brominated poly(meth)acrylate, brominated polycarbonate, and brominated epoxy are more preferred, and brominated polycarbonate is more preferred.

[0062] The brominated phthalimide is preferably one represented by formula (4). [ka] (In formula (4), D represents an alkylene group, an arylene group, or a group formed by combining two or more of -S(=O)2-, -C(=O)-, and -O-. i represents an integer of 1 to 4.)

[0063] In formula (4), D represents a group consisting of a combination of two or more of an alkylene group, an arylene group, -S(=O)2-, -C(=O)-, and -O-; a group consisting of a combination of an alkylene group or an arylene group and at least one of -S(=O)2-, -C(=O)-, and -O- is preferred; a group consisting of a combination of an alkylene group or an arylene group and one of -S(=O)2-, -C(=O)-, and -O- is more preferred; and an alkylene group is even more preferred. The group consisting of a combination of an alkylene group and -O- is intended to include, for example, a combination of two alkylene groups and one -O- (the same applies to other combinations). The alkylene group represented by D is preferably an alkylene group having 1 to 6 carbon atoms, more preferably a methylene group, an ethylene group, a propylene group or a butylene group. The arylene group is preferably a phenylene group. i is an integer of 1 to 4, and is preferably 4.

[0064] Examples of the brominated phthalimide represented by formula (4) include N,N'-(bistetrabromophthalimide)ethane, N,N'-(bistetrabromophthalimide)propane, N,N'-(bistetrabromophthalimide)butane, N,N'-(bistetrabromophthalimide)diethyl ether, N,N'-(bistetrabromophthalimide)dipropyl ether, N,N'-(bistetrabromophthalimide)dibutyl ether, N,N'-(bistetrabromophthalimide)diphenylsulfone, N,N'-(bistetrabromophthalimide)diphenyl ketone, and N,N'-(bistetrabromophthalimide)diphenyl ether.

[0065] The brominated phthalimide is more preferably a brominated phthalimide represented by formula (5). [ka] (In formula (5), i is an integer of 1 to 4.) i is an integer of 1 to 4, and is preferably 4.

[0066] The brominated poly(meth)acrylate is preferably a polymer obtained by polymerizing a bromine atom-containing benzyl (meth)acrylate alone, copolymerizing two or more types of bromine atom-containing benzyl (meth)acrylate, or copolymerizing the bromine atom with another vinyl monomer. The bromine atoms are attached to benzene rings, and the number of bromine atoms attached is preferably 1 to 5, and more preferably 4 to 5, per benzene ring.

[0067] Examples of the benzyl acrylate containing a bromine atom include pentabromobenzyl acrylate, tetrabromobenzyl acrylate, tribromobenzyl acrylate, and mixtures thereof. Examples of the benzyl methacrylate containing a bromine atom include methacrylates corresponding to the above-mentioned acrylates.

[0068] Specific examples of other vinyl monomers that can be copolymerized with the bromine atom-containing benzyl (meth)acrylate include acrylic acid esters such as acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and benzyl acrylate; methacrylic acid esters such as methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and benzyl methacrylate; unsaturated carboxylic acids or anhydrides thereof such as styrene, acrylonitrile, fumaric acid, and maleic acid; vinyl acetate; and vinyl chloride.

[0069] These are usually used in an equimolar amount or less, particularly preferably 0.5 times or less, of the amount of benzyl (meth)acrylate containing a bromine atom.

[0070] Furthermore, vinyl monomers such as xylene diacrylate, xylene dimethacrylate, tetrabromxylene diacrylate, tetrabromxylene dimethacrylate, butadiene, isoprene, and divinylbenzene can also be used, and these can usually be used in an amount of 0.5 times or less by mole relative to the bromine atom-containing benzyl acrylate or benzyl methacrylate.

[0071] The brominated poly(meth)acrylate is preferably a polymer obtained by polymerizing a bromine atom-containing (meth)acrylate monomer, particularly benzyl (meth)acrylate, alone or by copolymerizing two or more of them, or by copolymerizing them with other vinyl monomers. The bromine atoms are attached to the benzene ring, and the number of bromine atoms attached is preferably 1 to 5, more preferably 4 to 5, per benzene ring.

[0072] As the brominated poly(meth)acrylate, pentabromobenzyl poly(meth)acrylate is preferred because of its high bromine content.

[0073] The molecular weight of the brominated poly(meth)acrylate is optional and may be appropriately selected and determined, but the weight-average molecular weight (Mw) is preferably 3,000 or more, more preferably 10,000 or more, even more preferably 15,000 or more, even more preferably 20,000 or more, and even more preferably 25,000 or more. By setting the Mw at or above the lower limit, molded articles with higher mechanical strength tend to be obtained. Furthermore, the upper limit of the weight-average molecular weight (Mw) is preferably 100,000 or less, more preferably 80,000 or less, even more preferably 60,000 or less, even more preferably 50,000 or less, and even more preferably 35,000 or less. By setting the Mw at or below the upper limit, the flowability of the composition tends to be further improved.

[0074] The brominated polycarbonate preferably has a free bromine content of 0.05% by mass or more and preferably 0.20% by mass or less. By adjusting the content within these ranges, the heat resistance stability of the composition tends to be further improved. The brominated polycarbonate also preferably has a chlorine atom content of 0.001% by mass or more and preferably 0.20% by mass or less. By adjusting the content within these ranges, the mold corrosion resistance during molding tends to be further improved. Specifically, the brominated polycarbonate is preferably a brominated polycarbonate obtained from brominated bisphenol A, particularly tetrabromobisphenol A. Examples of the terminal structure include a phenyl group, a 4-t-butylphenyl group, and a 2,4,6-tribromophenyl group, and particularly, those having a 2,4,6-tribromophenyl group in the terminal group structure are preferred.

[0075] The average number of carbonate structural units in the brominated polycarbonate may be appropriately selected and determined, but is preferably 2-30, more preferably 3-15, and even more preferably 3-10.

[0076] The molecular weight of the brominated polycarbonate is optional and may be appropriately selected and determined, but preferably has a viscosity average molecular weight of 1,000 to 20,000, and more preferably 2,000 to 10,000.

[0077] The brominated polycarbonate obtained from the above brominated bisphenol A can be obtained, for example, by a conventional method of reacting brominated bisphenol with phosgene. The end-capping agent includes an aromatic monohydroxy compound, which may be substituted with a halogen or an organic group.

[0078] Specific preferred examples of the brominated epoxy include bisphenol A type brominated epoxy compounds, such as tetrabromobisphenol A epoxy compounds and glycidyl brominated bisphenol A epoxy compounds.

[0079] The molecular weight of the brominated epoxy compound is optional and may be appropriately selected and determined. However, the weight average molecular weight (Mw) is preferably 3,000 or more, more preferably 10,000 or more, even more preferably 13,000 or more, even more preferably 15,000 or more, and even more preferably 18,000 or more. By setting the weight average molecular weight at or above the lower limit, molded articles with higher mechanical strength tend to be obtained. Furthermore, the upper limit of the weight average molecular weight (Mw) is preferably 100,000 or less, more preferably 80,000 or less, even more preferably 78,000 or less, even more preferably 75,000 or less, and even more preferably 70,000 or less. By setting the weight average molecular weight at or below the upper limit, the flowability of the composition tends to be further improved. The brominated epoxy compound preferably has an epoxy equivalent of 3,000 to 40,000 g / eq, more preferably 4,000 to 35,000 g / eq, and particularly preferably 10,000 to 30,000 g / eq.

[0080] Brominated epoxy oligomers can also be used in combination as brominated epoxy compounds. In this case, for example, by using oligomers with Mw of 5,000 or less in a proportion of about 50% by mass or less, flame retardancy, mold releasability, and flowability can be appropriately adjusted. The bromine atom content in the brominated epoxy compound is optional, but to provide sufficient flame retardancy, it is usually 10% by mass or more, preferably 20% by mass or more, and particularly preferably 30% by mass or more. The upper limit is 60% by mass, and preferably 55% by mass or less.

[0081] The brominated polystyrene preferably includes a brominated polystyrene containing a constitutional unit represented by formula (6). [ka] (In formula (6), t is an integer of 1 to 5, and n is the number of constitutional units.)

[0082] Brominated polystyrene can be produced by either brominating polystyrene or polymerizing brominated styrene monomers. Polymerization of brominated styrene is preferred because it contains a smaller amount of free bromine atoms. In formula (6), the CH group to which the brominated benzene is bonded may be substituted with a methyl group. Brominated polystyrene may also be a copolymer copolymerized with other vinyl monomers. Examples of vinyl monomers in this case include styrene, α-methylstyrene, (meth)acrylonitrile, methyl (meth)acrylate, butadiene, and vinyl acetate. Brominated polystyrene may be used alone or as a mixture of two or more different structures, and may contain units derived from styrene monomers with different bromine numbers in a single molecular chain.

[0083] Specific examples of brominated polystyrene include poly(4-bromostyrene), poly(2-bromostyrene), poly(3-bromostyrene), poly(2,4-dibromostyrene), poly(2,6-dibromostyrene), poly(2,5-dibromostyrene), poly(3,5-dibromostyrene), poly(2,4,6-tribromostyrene), poly(2,4,5-tribromostyrene), poly(2,3,5-tribromostyrene), and poly(4-bromo-α-methylstyrene). Examples of suitable styrene copolymers include poly(2,4-dibromostyrene), poly(2,4-dibromo-α-methylstyrene), poly(2,5-dibromo-α-methylstyrene), poly(2,4,6-tribromo-α-methylstyrene), and poly(2,4,5-tribromo-α-methylstyrene), and poly(2,4,6-tribromostyrene), poly(2,4,5-tribromostyrene), and polydibromostyrene and polytribromostyrene containing an average of 2 to 3 bromine groups in the benzene ring are particularly preferred.

[0084] The brominated polystyrene preferably has the number n (average degree of polymerization) of structural units in formula (6) of 30 to 1,500, more preferably 150 to 1,000, and particularly preferably 300 to 800. If the average degree of polymerization is less than 30, blooming is likely to occur, while if it exceeds 1,500, poor dispersion is likely to occur and mechanical properties are likely to deteriorate. The weight-average molecular weight (Mw) of the brominated polystyrene is preferably 5,000 to 500,000, more preferably 10,000 to 500,000, even more preferably 10,000 to 300,000, even more preferably 10,000 to 100,000, and even more preferably 10,000 to 70,000. In particular, in the case of the brominated polystyrene described above, the weight average molecular weight (Mw) is preferably 50,000 to 70,000, and in the case of brominated polystyrene obtained by polymerization, the weight average molecular weight (Mw) is preferably about 10,000 to 30,000. The weight average molecular weight (Mw) can be determined as a value converted into standard polystyrene by GPC measurement.

[0085] The bromine concentration in the brominated flame retardant is preferably 45% by mass or more, more preferably 48% by mass or more, and even more preferably 50% by mass or more. By setting the bromine concentration at or above the lower limit, the flame retardancy of the molded article tends to be effectively improved. The upper limit of the bromine concentration is preferably 75% by mass or less, more preferably 73% by mass or less, and even more preferably 71% by mass or less.

[0086] Furthermore, when the composition used in this embodiment contains a halogen-based flame retardant, the content thereof is preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, even more preferably 0.03 parts by mass or more, even more preferably 0.04 parts by mass or more, and even more preferably 0.05 parts by mass or more, per 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. By setting the content at or above the lower limit, the flame retardancy of the resulting molded article tends to be improved, and the mechanical strength retention rate tends to be increased. Furthermore, the upper limit of the content of the halogen-based flame retardant is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less, per 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. By setting the content at or below the upper limit, the appearance and mechanical strength of the resulting molded article tend to be further improved. The composition used in this embodiment may contain only one halogen-based flame retardant, or may contain two or more. When two or more types are contained, the total amount is preferably in the above range.

[0087] <Flow modifier> The composition used in this embodiment preferably contains 0.5 to 30 parts by mass of a flow modifier per 100 parts by mass of a polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. By containing a flow modifier, the flowability of the polycarbonate resin can be improved while maintaining excellent flexural strength.

[0088] The flow modifier used in this embodiment may be a known one, and may be a low molecular weight or oligomer (number average molecular weight less than 2000) or a polymer (number average molecular weight 2000 or more). In this embodiment, for example, an oligomer having a number average molecular weight of 1000 or more but less than 2000 can be used. The number average molecular weight here is a polystyrene-equivalent value measured by GPC (gel permeation chromatography). Specific examples include polyester oligomers, polycarbonate oligomers, polycaprolactone, low molecular weight acrylic copolymers, and aliphatic rubber-polyester block copolymers, with polycarbonate oligomers being preferred. For details of the flow improver, please refer to the descriptions in paragraphs 0050 to 0056 of Japanese Patent No. 4736260 and paragraphs 0059 to 0070 of JP-A No. 2011-063812, the contents of which are incorporated herein by reference.

[0089] In the composition used in this embodiment, the content of the flow modifier is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, even more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, relative to 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. By setting the content at or above the lower limit, the fluidity of the polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm tends to be further improved. The content of the flow modifier is also preferably 30 parts by mass or less, more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, even more preferably 17 parts by mass or less, even more preferably 16 parts by mass or less, and may even be 13 parts by mass or less, relative to 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm. By setting the content at or below the upper limit, the fluidity of the polycarbonate resin tends to be further improved without reducing heat resistance and impact resistance. The composition used in this embodiment may contain only one type of flow modifier, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0090] <Other ingredients> The composition used in this embodiment may contain other components in addition to those described above. Examples include thermoplastic resins other than polycarbonate resins, anti-dripping agents, flame retardant aids, dyes, pigments, impact resistance modifiers, antistatic agents, slip agents, anti-blocking agents, release agents, anti-fogging agents, natural oils, synthetic oils, waxes, organic fillers, etc. The total amount of these components may be, for example, 0.1 to 10% by mass of the composition. The composition used in this embodiment may contain, for example, 0.1 to 10 parts by mass (preferably 0.5 to 5 parts by mass) in total of at least one selected from a release agent and carbon black per 100 parts by mass of polycarbonate resin. Regarding the release agent, the descriptions in paragraphs 0054 to 0064 of JP 2021-031633 A and paragraphs 0038 to 0044 of JP 2019-056035 A can be referred to, the contents of which are incorporated herein by reference. For carbon black, the descriptions in paragraphs 0065 to 0068 of JP 2021-031633 A and paragraphs 0014 to 0025 of JP 2019-056035 A can be referred to, the contents of which are incorporated herein by reference.

[0091] <Physical properties> A molded article obtained from the pellets of this embodiment preferably has a high bending strength close to that of a polycarbonate resin blended with virgin carbon fiber. The flexural strength measured according to ISO 178 using an ISO multipurpose test specimen molded from the composition of this embodiment preferably has a retention rate of 88% or more compared to the flexural strength measured according to ISO 178 using an ISO multipurpose test specimen molded from a composition in which the polycarbonate resin contained in the composition is replaced with an equivalent amount of polycarbonate resin having a terminal hydroxyl group content of 140 ppm and the recycled carbon fiber is replaced with an equivalent amount of virgin carbon fiber. The ISO multipurpose test specimen is a flat test specimen measuring 80 mm x 10 mm x 4 mm (e.g., a flat test specimen measuring 80 mm x 10 mm x 4 mm cut from an ISO multipurpose test specimen). The retention rate is more preferably 90% or more, even more preferably 92% or more, and even more preferably 94% or more. A practical upper limit of the above value is 105% or less. Such a high retention rate can be achieved by using a polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm.

[0092] <Pellet manufacturing method> The pellets used in this embodiment can be produced by a conventional method for producing pellets containing polycarbonate resin. For example, the pellets used in this embodiment can be produced by a method including feeding 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm, 5 to 40 parts by mass of recycled carbon fiber, which is a heated carbon fiber reinforced resin, and 5 to 40 parts by mass of an inorganic filler into an extruder and melt-kneading them. Recycled carbon fiber may not have a surface treatment agent or sizing agent attached to the surface of the carbon fiber. However, in this embodiment, by using a heated carbon fiber reinforced resin as the recycled carbon fiber, resin-derived residues act as surface treatment agents, etc., making it possible to feed the recycled carbon fiber into an extruder and melt-knead it. Therefore, pellets can be produced. The components may be premixed and fed to the extruder all at once, or the components may be premixed without premixing or only a portion of the components may be premixed and fed to the extruder using a feeder. The extruder may be a single-screw extruder or a twin-screw extruder. Alternatively, a masterbatch may be prepared by melt-kneading a portion of the dye or pigment (e.g., carbon black) with a resin component, and then the remaining components may be blended and melt-kneaded. It is also preferable to feed the carbon fiber from a side feeder midway through the cylinder of the extruder. The heating temperature during melt-kneading can usually be appropriately selected from the range of 250 to 350°C.

[0093] The molded article of this embodiment is formed from the pellets of this embodiment. The molded article of this embodiment has good mechanical strength and can be used in a variety of applications, such as various storage containers, electrical and electronic equipment parts, office automation (OA) equipment parts, home appliance parts, machine mechanism parts, and vehicle mechanism parts.

[0094] <Method of manufacturing molded products> The method for producing the molded article of this embodiment is not particularly limited, and any molding method generally used for compositions or pellets containing polycarbonate resin can be used. Examples include injection molding, ultra-high speed injection molding, injection compression molding, two-color molding, gas-assisted hollow molding, molding using a heat-insulating mold, molding using a rapidly heated mold, foam molding (including supercritical fluid), insert molding, IMC (in-mold coating molding), extrusion molding, sheet molding, thermoforming, rotational molding, lamination molding, press molding, blow molding, etc., among which injection molding is preferred. For details of injection molding, please refer to the description in paragraphs 0113 to 0116 of Japanese Patent No. 6183822, the contents of which are incorporated herein by reference. [Example]

[0095] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, processing details, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or the like, measurements can be made using other instruments with equivalent performance.

[0096] 1.Raw materials The raw material components used in the following Examples and Comparative Examples are as shown in Tables 1 and 2 below. [Table 1] [Table 2]

[0097] <Amount of residue> The residue of recycled carbon fiber in Table 1 indicates the amount of char in the recycled carbon fiber. That is, since the recycled carbon fiber used in this example is a burned product of a composite of resin (e.g., epoxy resin) and carbon fiber, the recycled carbon fiber contains residue (char) derived from the resin (e.g., epoxy resin). The amount of resin residue is a value obtained by calculating the mass of carbon fiber contained in the carbon fiber reinforced resin before heat treatment from the carbon fiber content and using formula (X). The unit is shown as % by mass. (BA × C) / (B) × 100 Equation (X) A: Mass of carbon fiber reinforced resin before heat treatment B: Mass of the heat-treated material C: Carbon fiber content of carbon fiber reinforced resin before heat treatment

[0098] <Amount of terminal hydroxyl groups in polycarbonate resin> The amount of terminal hydroxyl groups in polycarbonate resin (PC resin) represents the total amount of terminal hydroxyl groups shown below, and is the ratio of the mass of terminal hydroxyl groups to the total mass of the polycarbonate resin, expressed in ppm. The measurement method was colorimetric determination using the titanium tetrachloride / acetic acid method (the method described in Macromol. Chem. 88 215 (1965)). [ka] In the above formula, R 5 is a group selected from a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, a cycloalkyl group having 4 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms, and r represents an integer of 0 to 2. When r is 2, two R 5 may be the same or different. The wavy line portions indicate the bonding positions with the main chain of the polycarbonate resin.

[0099] 2. Examples 1 to 6 and Comparative Examples 1 to 10 <Compound> The raw materials listed in Tables 3 to 5 were mixed in the amounts listed in the tables (all parts by mass), and then a twin-screw extruder equipped with one vent was used. The raw materials other than the carbon fiber were fed into the extruder from the barrel upstream of the extruder, and the carbon fiber was side-fed. The mixture was kneaded under conditions of a screw rotation speed of 300 rpm, a discharge rate of 200 kg / hour, and a barrel temperature of 280 to 310°C, and the molten pellets extruded in the form of strands were quenched in a water tank and pelletized using a pelletizer to obtain pellets.

[0100] <Molding of test specimens> The pellets obtained above were dried at 120°C for 5 hours and then injection molded in an injection molding machine (Japan Steel Works, Ltd., "J85AD") under conditions of a cylinder temperature of 300°C, a mold temperature of 100°C, and a molding cycle of 50 seconds to produce ISO multipurpose test specimens (4 mm thick).

[0101] <Tensile strength, tensile modulus and tensile strain> Using the ISO multipurpose test specimen obtained above, tensile tests were carried out in accordance with ISO527-1 and ISO527-2 to determine the tensile strength, tensile modulus, and tensile strain. The units of tensile strength and tensile modulus are MPa, and the unit of tensile strain is %.

[0102] <Flexural strength, flexural strength retention rate, and flexural modulus> Using the ISO multipurpose test specimen obtained above, flat test specimens measuring 80 mm x 10 mm x 4 mm thick were prepared, and the flexural strength and flexural modulus of the test specimens were measured in accordance with ISO 178. The flexural strength retention rate was also calculated. The units of flexural strength and flexural modulus are MPa, and the unit of flexural strength retention is %.

[0103] The bending strength retention rates of Comparative Examples 1 and 2 and Example 1 are shown as relative values ​​when the bending strength of Comparative Example 1 is taken as 100%; those of Comparative Examples 3 and 4 and Example 2 are shown as relative values ​​when the bending strength of Comparative Example 3 is taken as 100%; those of Comparative Examples 5, 6 and Example 3 are shown as relative values ​​when the bending strength of Comparative Example 5 is taken as 100%; those of Comparative Examples 7, 8 and Example 4 are shown as relative values ​​when the bending strength of Comparative Example 7 is taken as 100%; those of Comparative Example 9 and Example 5 are shown as relative values ​​when the bending strength of Comparative Example 9 is taken as 100%; and those of Comparative Example 10 and Example 6 are shown as relative values ​​when the bending strength of Comparative Example 10 is taken as 100%.

[0104] <Unnotched Charpy impact strength> Using the ISO multipurpose test specimen obtained above, the Charpy impact strength (unnotched) was measured at 23°C in accordance with ISO179-1 and ISO179-2. The unit is kJ / m 2 As shown.

[0105] [Table 3]

[0106] [Table 4]

[0107] [Table 5]

[0108] As is clear from the above results, the molded articles formed from the pellets of this embodiment were able to achieve mechanical strength close to that of articles made from virgin carbon fibers, despite using recycled carbon fibers (Examples 1 to 6).

Claims

1. A pellet formed from a composition containing 100 parts by mass of polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm, 5 to 40 parts by mass of recycled carbon fiber which is a heated carbon fiber reinforced resin, and 5 to 40 parts by mass of an inorganic filler, The recycled carbon fiber is a pellet obtained by heating a carbon fiber reinforced resin, and the proportion of resin residue is 5 to 20 mass %.

2. The pellet according to claim 1, wherein the flexural strength measured in accordance with ISO 178 using an ISO multipurpose test piece molded from the composition has a retention rate of 88% or more compared to the flexural strength measured in accordance with ISO 178 using an ISO multipurpose test piece molded from a composition in which the polycarbonate resin contained in the composition is replaced with a polycarbonate resin having an equivalent amount of terminal hydroxyl groups of 140 ppm and the recycled carbon fiber is replaced with virgin carbon fiber having an equivalent amount of carbon fiber.

3. 3. The pellet of claim 1 or 2, wherein the polycarbonate resin comprises recycled polycarbonate resin.

4. The pellet according to any one of claims 1 to 3, wherein the inorganic filler comprises a glass filler.

5. The pellet according to any one of claims 1 to 4, further comprising 0.5 to 30 parts by mass of a flow modifier per 100 parts by mass of the polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm.

6. The pellet according to any one of claims 1 to 5, further comprising 0.1 to 10 parts by mass in total of at least one selected from a release agent and carbon black per 100 parts by mass of the polycarbonate resin having a terminal hydroxyl group amount of 150 to 800 ppm.

7. A molded article formed from the pellets according to any one of claims 1 to 6.

8. The method includes introducing 100 parts by mass of a polycarbonate resin having a terminal hydroxyl group content of 150 to 800 ppm, 5 to 40 parts by mass of recycled carbon fiber which is a heated carbon fiber reinforced resin, and 5 to 40 parts by mass of an inorganic filler into an extruder and melt-kneading them, The recycled carbon fiber is a heated carbon fiber reinforced resin, and the proportion of resin residue is 5 to 20 mass %.

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