Polycarbonate resin composition

Abstract

To provide a polycarbonate resin composition exhibiting high dielectric constant and low dielectric loss tangent.SOLUTION: A polycarbonate resin composition contains, relative to 100 pts.mass of an aromatic polycarbonate resin (A), 1 pt.mass or more and less than 9 pts.mass of recycled carbon fiber (B) and has a relative permittivity of 3.5 or more and a dielectric loss tangent of less than 0.03.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polycarbonate resin composition, and more particularly to a polycarbonate resin composition having high dielectric properties and a low dielectric loss tangent, and a molded article thereof. [Background technology]

[0002] Polycarbonate resins have excellent impact resistance, heat resistance, electrical insulation properties, dimensional stability, and other properties, and because they have a good balance of these properties, they are widely used in fields such as electrical and electronic equipment parts, information and communication equipment parts, office automation equipment parts, precision machinery parts, and vehicle parts.

[0003] Polycarbonate resin materials are increasingly being used in touch panel modules for electronic devices such as mobile phones, car navigation systems, and personal computers to reduce weight, but the dielectric constant must be increased to improve the sensitivity of the touch sensor. In recent years, frequencies in the field of information and communication devices have been increasing. Materials used in such devices are required to have high dielectric properties and low dielectric loss to avoid energy loss. Since dielectric loss increases in proportion to frequency and dielectric loss tangent, achieving low dielectric loss at high frequencies requires reducing the dielectric loss tangent.

[0004] To increase the dielectric constant of resin materials, it is known to add a high-dielectric metal oxide filler such as barium titanate to the resin, or to add a conductive filler such as carbon black or metal. Carbon fiber is usually used as a reinforcing material, and is not usually used for the purpose of increasing the dielectric constant because of its large dielectric loss tangent. Patent Document 1 proposes a resin composition containing 5 to 65 parts by mass of recycled carbon fiber, which is a heated carbon fiber reinforced resin, per 100 parts by mass of polycarbonate resin, as a composition having mechanical strength as close as possible to that of a composition containing virgin carbon fiber. However, the invention of Patent Document 1 does not disclose anything about the dielectric constant or dielectric loss tangent. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. WO2021 / 230132 Summary of the Invention [Problem to be solved by the invention]

[0006] An object (object) of the present invention is to provide a polycarbonate resin composition having high dielectric properties and a low dielectric loss tangent. [Means for solving the problem]

[0007] The present inventors have discovered that recycled carbon fibers deteriorate due to heat during processing, and that the dielectric tangent of a resin composition using such recycled carbon fibers decreases, leading to the present invention. The present invention provides the following polycarbonate resin composition and molded article.

[0008] 1. A polycarbonate resin composition characterized by containing 1 part by mass or more and less than 9 parts by mass of recycled carbon fiber (B) per 100 parts by mass of aromatic polycarbonate resin (A), and having a relative dielectric constant of 3.5 or more and a dielectric dissipation factor of less than 0.03. 2. The polycarbonate resin composition according to the above item 1, wherein the recycled carbon fiber (B) contains 20% by mass or less of residual carbonized material derived from the resin. 3. The polycarbonate resin composition according to the above 1 or 2, wherein the aromatic polycarbonate resin (A) has terminal hydroxyl groups in an amount of less than 150 ppm by mass. 4. The polycarbonate resin composition according to any one of the above 1 to 3, wherein the aromatic polycarbonate resin (A) has terminal hydroxyl groups in an amount of 150 ppm by mass or more. 5. The polycarbonate resin composition according to any one of 1 to 4 above, wherein the content of the recycled carbon fibers (B) is 5 parts by mass or more and less than 9 parts by mass per 100 parts by mass of the aromatic polycarbonate resin (A). 6. The polycarbonate resin composition according to any one of the above 1 to 4, wherein the content of the recycled carbon fibers (B) is 1 part by mass or more and less than 5 parts by mass per 100 parts by mass of the aromatic polycarbonate resin (A). 7. Pellets of the resin composition according to any one of 1 to 6 above. 8. A molded article made from the resin composition according to any one of 1 to 6 above. 9. A molded product of the pellets described in 7 above. [Effects of the Invention]

[0009] The polycarbonate resin composition of the present invention has a high dielectric constant of 3.5 or more and a low dielectric loss tangent of less than 0.03, and is particularly suitable for use as a high-dielectric, low-dielectric loss tangent resin material in various electrical and electronic device components, etc. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below by showing embodiments and examples, but the present invention is not limited to the embodiments and examples shown below, and can be modified and implemented as desired within the scope that does not deviate from the gist of the present invention.

[0011] The polycarbonate resin composition of the present invention is characterized by containing 1 part by mass or more and less than 9 parts by mass of recycled carbon fiber (B) per 100 parts by mass of aromatic polycarbonate resin (A), and having a relative dielectric constant of 3.5 or more and a dielectric dissipation factor of less than 0.03.

[0012] [Aromatic polycarbonate resin (A)] The aromatic polycarbonate resin (A) contained in the resin composition of the present invention is an aromatic polycarbonate resin in which each carbon atom directly bonded to a carbonate bond is an aromatic carbon atom, from the viewpoints of heat resistance, mechanical properties, electrical properties, etc.

[0013] Among the monomers that are raw materials for aromatic polycarbonate resins, examples of aromatic dihydroxy compounds include: dihydroxybenzenes such as 1,2-dihydroxybenzene, 1,3-dihydroxybenzene (i.e., resorcinol), and 1,4-dihydroxybenzene; dihydroxybiphenyls such as 2,5-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl, and 4,4'-dihydroxybiphenyl;

[0014] dihydroxynaphthalenes such as 2,2'-dihydroxy-1,1'-binaphthyl, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, and 2,7-dihydroxynaphthalene;

[0015] dihydroxydiaryl ethers such as 2,2'-dihydroxydiphenyl ether, 3,3'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, 1,4-bis(3-hydroxyphenoxy)benzene, and 1,3-bis(4-hydroxyphenoxy)benzene;

[0016] 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), 1,1-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane (i.e., bisphenol C), 2,2-bis(3-methoxy-4-hydroxyphenyl)propane, 2-(4-hydroxyphenyl)-2-(3-methoxy-4-hydroxyphenyl)propane, 1,1-bis(3-tert-butyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 2-(4-hydroxyphenyl)-2-(3-cyclohexyl-4-hydroxyphenyl)propane, α,α'-bis(4-hydroxyphenyl)-1,4-diisopropylbenzene, 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene, bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)cyclohexylmethane, bis(4-hydroxyphenyl)phenylmethane, bis(4-hydroxyphenyl)(4-propenylphenyl)methane, bis(4-hydroxyphenyl)diphenylmethane, bis(4-hydroxyphenyl)naphthylmethane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,1-bis(4-hydroxyphenyl)-1-naphthylethane, 1,1-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)pentane, 1,1-bis(4-hydroxyphenyl)hexane, 2,2-bis(4-hydroxyphenyl)hexane, 1,1-bis(4-hydroxyphenyl)octane, 2,2-bis(4-hydroxyphenyl)octane, 4,4-bis(4-hydroxyphenyl)heptane, 2,2-bis(4-hydroxyphenyl)nonane, 1,1-bis(4-hydroxyphenyl)decane, 1,1-bis(4-hydroxyphenyl)dodecane, Bis(hydroxyaryl)alkanes such as;

[0017] 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3-dimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,4-dimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,5-dimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxy-3,5-dimethylphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3-propyl-5-methylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3-tert-butyl-cyclohexane, 1,1-bis(4-hydroxyphenyl)-4-tert-butyl-cyclohexane, 1,1-bis(4-hydroxyphenyl)-3-phenylcyclohexane, 1,1-bis(4-hydroxyphenyl)-4-phenylcyclohexane, Bis(hydroxyaryl)cycloalkanes such as;

[0018] 9,9-bis(4-hydroxyphenyl)fluorene, Cardo structure-containing bisphenols such as 9,9-bis(4-hydroxy-3-methylphenyl)fluorene;

[0019] 4,4'-dihydroxydiphenyl sulfide, Dihydroxydiaryl sulfides such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide; dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide; 4,4'-dihydroxydiphenyl sulfone, dihydroxydiarylsulfones such as 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone; etc.

[0020] Of these, bis(hydroxyaryl)alkanes are preferred, and bis(4-hydroxyphenyl)alkanes are particularly preferred. In particular, from the standpoints of impact resistance and heat resistance, 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A) and 2,2-bis(3-methyl-4-hydroxyphenyl)propane (i.e., bisphenol C) are preferred. The aromatic dihydroxy compounds may be used alone or in any combination of two or more in any ratio.

[0021] Among the monomers that serve as raw materials for polycarbonate resins, examples of carbonate precursors include carbonyl halides, carbonate esters, etc. The carbonate precursors may be used alone or in any combination and ratio of two or more.

[0022] Specific examples of carbonyl halides include phosgene; haloformates such as bischloroformates of dihydroxy compounds and monochloroformates of dihydroxy compounds; and the like.

[0023] Specific examples of carbonate esters include diaryl carbonates such as diphenyl carbonate and ditolyl carbonate.

[0024] The method for producing the aromatic polycarbonate resin (A) is not particularly limited, and any method can be used. Examples include interfacial polymerization, melt transesterification, pyridine method, ring-opening polymerization of a cyclic carbonate compound, and solid-phase transesterification of a prepolymer. Among these, the interfacial polymerization method is particularly preferred.

[0025] Furthermore, the aromatic polycarbonate resin (A) may be not only virgin raw materials but also polycarbonate resin recycled from used products (so-called material-recycled polycarbonate resin, hereinafter also referred to as "recycled polycarbonate resin"). It is also preferable that it contains both virgin raw materials and recycled polycarbonate resin, or it may consist of recycled polycarbonate resin. When recycled polycarbonate resin is used, the proportion of recycled polycarbonate resin in the aromatic polycarbonate resin (A) is preferably 30 mass% or more, 40 mass% or more, 50 mass% or more, 60 mass% or more, or 80 mass% or more, and it is also preferable that the recycled polycarbonate resin is 100 mass%.

[0026] The molecular weight of the aromatic polycarbonate resin (A), expressed as a viscosity average molecular weight (Mv) calculated from the solution viscosity measured at 25°C using methylene chloride as a solvent, is preferably 10,000 to 50,000, more preferably 10,000 to 40,000, even more preferably 10,000 to 30,000 or 10,000 to 26,000, and even more preferably 10,500 or more, 11,000 or more, particularly 11,500 or more, most preferably 12,000 or more, and even more preferably 25,000 or less, particularly preferably 24,000 or less. By setting the viscosity average molecular weight to at least the lower limit of the above range, the mechanical strength of the polycarbonate resin composition of the present invention can be further improved, and by setting the viscosity average molecular weight to at most the upper limit of the above range, the decrease in flowability of the polycarbonate resin composition of the present invention can be suppressed and improved, and molding processability can be improved, allowing for easier molding processability. Two or more polycarbonate resins having different viscosity average molecular weights may be mixed together, and in this case, polycarbonate resins having viscosity average molecular weights outside the above-mentioned preferred range may be mixed.

[0027] The viscosity average molecular weight [Mv] is calculated by using methylene chloride as a solvent and an Ubbelohde viscometer to determine the intrinsic viscosity [η] (unit: dl / g) at a temperature of 25°C, and then calculating it using the Schnell viscosity formula, i.e., η = 1.23 × 10 -4 Mv 0.83The intrinsic viscosity [η] is the specific viscosity [η] at each solution concentration [C] (g / dl). sp ] was measured and the value was calculated according to the following formula.

number

[0028] The amount of terminal hydroxyl groups in the aromatic polycarbonate resin (A) is preferably 150 ppm by mass or more, more preferably 200 ppm by mass or more, and particularly preferably 250 ppm by mass or more, 300 ppm by mass or more, 350 ppm by mass or more, 400 ppm by mass or more, 450 ppm by mass or more, and 500 ppm by mass or more. By setting the amount to be above the lower limit, the adhesion between the carbon fiber surface and the polycarbonate resin is improved, and the transesterification reaction rate is increased, making it easier to obtain a polycarbonate resin having the desired molecular weight. In addition, the amount of residual carbonate ester in the polycarbonate resin can be reduced, which tends to more effectively suppress odors during molding processing or when molded into a molded article. The amount of terminal hydroxyl groups is preferably 800 ppm by mass or less, and particularly may be 750 ppm by mass or less, 700 ppm by mass or less, 650 ppm by mass or less, 630 ppm by mass or less, or 610 ppm by mass or less. By making the content equal to or less than the upper limit, the thermal stability of the polycarbonate resin tends to be further improved.

[0029] The amount of terminal hydroxyl groups in the aromatic polycarbonate resin (A) represents the total amount of terminal hydroxyl groups, and is the ratio of the mass of terminal hydroxyl groups to the mass of the aromatic polycarbonate resin, expressed in ppm by mass. The measurement method is in accordance with the colorimetric method using titanium tetrachloride / acetic acid (the method described in Macromol. Chem. 88 215 (1965)).

[0030] [ka] In the above formula, R represents 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, the two R may be the same or different. The wavy line portion indicates the bonding position to the main chain of the polycarbonate resin. When two or more types of polycarbonate resins are contained, the amount of terminal hydroxyl groups is the amount of the polycarbonate resin mixture.

[0031] Polycarbonate resins having terminal hydroxyl groups of 150 ppm by mass or more can be produced, for example, by melt polymerization. Recycled polycarbonate resins usually have terminal hydroxyl groups of 150 ppm by mass or more.

[0032] The amount of terminal hydroxyl groups in the aromatic polycarbonate resin (A) is also preferably less than 150 ppm by mass, more preferably 145 ppm by mass or less, and preferably 100 ppm by mass or more. By making it less than 150 ppm by mass, the fluidity of the polycarbonate resin in the low shear region tends to be further improved.

[0033] A polycarbonate resin having a terminal hydroxyl group content of less than 150 ppm by mass can be produced, for example, by an interfacial method.

[0034] Furthermore, in order to improve the appearance and flowability of the molded article, the aromatic polycarbonate resin (A) may contain a polycarbonate oligomer. The viscosity average molecular weight [Mv] of this polycarbonate oligomer is usually 1500 or more, preferably 2000 or more, and usually 9500 or less, preferably 9000 or less. The amount of the polycarbonate oligomer contained is preferably 30% by mass or less of the polycarbonate resin (including the polycarbonate oligomer). The amount of the aromatic polycarbonate resin (A) is preferably 60 to 99 mass % in the polycarbonate resin composition.

[0035] [Recycled carbon fiber (B)] The polycarbonate resin composition of the present invention contains recycled carbon fibers (B). Recycled carbon fiber refers to carbon fiber recovered from, for example, used carbon fiber reinforced resin, carbon fiber reinforced resin products (aircraft, vehicles, electrical and electronic devices, etc.), intermediate carbon fiber reinforced resin products (e.g., prepreg, sheet molding sheets, etc.), or scraps and rejected products generated during the manufacturing process of carbon fiber reinforced resin, carbon fiber reinforced resin products, and intermediate products. In contrast, virgin carbon fiber is unused carbon fiber that is not recycled, such as that generally sold as carbon fiber. The type of carbon fiber is not particularly limited, but PAN-based carbon fiber is preferred.

[0036] The resin in the carbon fiber reinforced resin may be a thermosetting resin or a thermoplastic resin. The thermosetting resin may be uncured or cured. Examples of the thermosetting resin include unsaturated polyester, epoxy, phenol, vinyl ester, bismaleimide, cyanate, and polyimide-based thermosetting resins. Examples of the thermoplastic resin include polyamide, polyolefin, polyester, polycarbonate, acrylic resin, ABS resin, polyetherimide, polyether ether ketone, and polyphenylene sulfide. The resin may contain additives such as a curing agent, a curing aid, a sizing agent, a surface treatment agent, an internal mold release agent, an antioxidant, a light stabilizer, a flame retardant, an ultraviolet absorber, and a colorant.

[0037] Recycled carbon fibers are usually obtained by heating carbon fiber reinforced resin. The heating temperature is usually 300 to 700°C, preferably 400 to 700°C, and more preferably 400 to 600°C, and the resin in the carbon fiber reinforced resin is converted into carbonized material, which remains as a residue on the surface of the carbon fiber. It is predicted that the chemical bonds of recycled carbon fibers are oxidized by the heating during recycling, resulting in a decrease in the dielectric loss tangent.

[0038] The content of residual carbonized resin-derived material (hereinafter also referred to as "resin residue") in the recycled carbon fiber is preferably 20% by mass or less, more preferably 15% by mass or less, and preferably 5% by mass or more, particularly preferably 7% by mass or more, 10% by mass or more, based on 100% by mass of the recycled carbon fiber. The recycled fibers may be surface treated with a sizing agent.

[0039] The number average fiber diameter of the recycled carbon fibers is preferably 3 μm or more, and more preferably 4 μm or more, and is preferably 10 μm or less, and more preferably 8 μm or less.

[0040] The content of recycled carbon fiber (B) is 1 part by mass or more and less than 9 parts by mass per 100 parts by mass of aromatic polycarbonate resin (A). It is preferably 2 parts by mass or more. It is also preferably 8.5 parts by mass or less, more preferably 8 parts by mass or less, even more preferably 7.5 parts by mass or less, and particularly preferably 7 parts by mass or less. It is preferably 2 parts by mass or more and 8.5 parts by mass or less, more preferably 4 parts by mass or more and 7 parts by mass or less. By including recycled carbon fiber (B) in such an amount, a resin composition with a high relative dielectric constant and a low dielectric loss tangent can be obtained. If the content of recycled carbon fiber (B) is 9 parts by mass or more, the dielectric loss tangent of the resulting polycarbonate resin composition will be high, and conversely, if it is less than 1 part by mass, the relative dielectric constant will be low. When the amount of terminal hydroxyl groups in the aromatic polycarbonate resin (A) is less than 150 ppm by mass, the content of recycled carbon fiber (B) is preferably 5 parts by mass or more and less than 9 parts by mass, since this increases the relative dielectric constant and also ensures a sufficient dielectric loss tangent. It is more preferably 5.5 parts by mass or more, and particularly preferably 6 parts by mass or more. It is even more preferably 8.5 parts by mass or less, and particularly preferably 7.5 parts by mass or less. It is preferably 5.5 parts by mass or more and 8.5 parts by mass or less, and particularly preferably 6 parts by mass or more and 7.5 parts by mass or less. When the amount of terminal hydroxyl groups in the aromatic polycarbonate resin (A) is 150 ppm by mass or more, the content of the recycled carbon fiber (B) is preferably 1 part by mass or more but less than 5 parts by mass, more preferably 2 parts by mass or more and 4.5 parts by mass or less. By including the recycled carbon fiber (B) in such an amount, a resin composition having a low dielectric tangent and a sufficient relative dielectric constant can be obtained. When two or more aromatic polycarbonate resins having different amounts of terminal hydroxyl groups are used in combination, the amount of terminal hydroxyl groups is the sum of the values ​​obtained by multiplying the amount of terminal hydroxyl groups of each aromatic polycarbonate resin by the mass proportion of each aromatic polycarbonate resin in the total aromatic polycarbonate resins. For example, in the case of Example 7, the total amount is 140 × 0.693 + 480 × 0.307 = 244.38 (ppm by mass).

[0041] The polycarbonate resin composition of the present invention may or may not contain virgin carbon fiber. One example of the composition of 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 of 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.

[0042] [Stabilizer] The polycarbonate resin composition of the present invention preferably contains a stabilizer, and the stabilizer is preferably a phosphorus-based stabilizer (antioxidant) or a phenol-based stabilizer (antioxidant).

[0043] Any known phosphorus-based stabilizer can be used. Specific examples include phosphorus oxoacids such as phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, and polyphosphoric acid; metal acid pyrophosphates such as sodium acid pyrophosphate, potassium acid pyrophosphate, and calcium acid pyrophosphate; phosphates of Group 1 or Group 2 metals such as potassium phosphate, sodium phosphate, cesium phosphate, and zinc phosphate; organic phosphate compounds, organic phosphite compounds, and organic phosphonite compounds, with organic phosphite compounds being particularly preferred.

[0044] Examples of organic phosphite compounds include triphenyl phosphite, tris(mononylphenyl)phosphite, tris(mononyl / dinonylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, monooctyldiphenyl phosphite, dioctylmonophenyl phosphite, monodecyldiphenyl phosphite, didecylmonophenyl phosphite, tridecyl phosphite, trilauryl phosphite, tristearyl phosphite, and 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite. Specific examples of such organic phosphite compounds include "ADK STAB 1178," "ADK STAB 2112," and "ADK STAB HP-10" manufactured by ADEKA CORPORATION, "JP-351," "JP-360," and "JP-3CP" manufactured by Johoku Chemical Industry Co., Ltd., and "IRGAFOS 168" manufactured by BASF. The phosphorus-based stabilizer may be contained either as one type or as two or more types in any combination and ratio.

[0045] The content of the phosphorus-based stabilizer is preferably 0.01 part by mass or more, more preferably 0.03 part by mass or more, and usually 1 part by mass or less, preferably 0.7 part by mass or less, more preferably 0.5 part by mass or less, relative to 100 parts by mass of the aromatic polycarbonate resin (A). If the content of the phosphorus-based stabilizer is less than the lower limit of the above range, the thermal stabilization effect may be insufficient, whereas if the content of the phosphorus-based stabilizer exceeds the upper limit of the above range, the effect may plateau and become uneconomical.

[0046] Examples of the phenolic stabilizer include hindered phenolic antioxidants. Specific examples thereof include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphate, 3,3',3",5,5',5"-hexa-tert-butyl-a,a',a"-(mesitylene-2,4,6- triyl)tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, and the like.

[0047] Among these, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate are preferred. Specific examples of such phenolic antioxidants include "Irganox 1010" and "Irganox 1076" manufactured by BASF, and "Adekastab AO-50" and "Adekastab AO-60" manufactured by ADEKA. The phenolic stabilizer may be contained in one kind or in any combination and ratio of two or more kinds.

[0048] The content of the phenolic stabilizer is preferably 0.01 parts by mass or more, and usually 1 part by mass or less, preferably 0.5 parts by mass or less, per 100 parts by mass of the aromatic polycarbonate resin (A). By setting the content of the phenolic stabilizer to the lower limit of the above range or more, the effect as a phenolic stabilizer can be sufficiently obtained. Furthermore, by setting the content of the phenolic stabilizer to the upper limit of the above range or less, the effect does not plateau and is economical.

[0049] [Release agent] The polycarbonate resin composition of the present invention preferably contains a mold release agent, such as an aliphatic carboxylic acid, an ester of an aliphatic carboxylic acid and an alcohol, an aliphatic hydrocarbon compound having a number average molecular weight of 200 to 15,000, or a polysiloxane-based silicone oil.

[0050] Examples of aliphatic carboxylic acids include saturated or unsaturated aliphatic mono-, di-, or tri-carboxylic acids. Aliphatic carboxylic acids also include alicyclic carboxylic acids. Among these, preferred aliphatic carboxylic acids are mono- or di-carboxylic acids having 6 to 36 carbon atoms, with saturated aliphatic mono-carboxylic acids having 6 to 36 carbon atoms being more preferred. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, tetralinic acid, montanic acid, adipic acid, and azelaic acid.

[0051] The aliphatic carboxylic acid in the ester of an aliphatic carboxylic acid and an alcohol can be, for example, the same as the aliphatic carboxylic acid described above. On the other hand, the alcohol can be, for example, a saturated or unsaturated monohydric or polyhydric alcohol. These alcohols may have a substituent such as a fluorine atom or an aryl group. Among these, a monohydric or polyhydric saturated alcohol having 30 or less carbon atoms is preferred, and an aliphatic saturated monohydric alcohol or an aliphatic saturated polyhydric alcohol having 30 or less carbon atoms is more preferred. Here, the term "aliphatic" is used to include alicyclic compounds.

[0052] Specific examples of such alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, and dipentaerythritol.

[0053] The ester may contain an aliphatic carboxylic acid and / or an alcohol as an impurity. The ester may be a pure substance or a mixture of multiple compounds. The aliphatic carboxylic acid and the alcohol that combine to form an ester may each be used alone or in any combination and ratio of two or more.

[0054] Specific examples of esters of aliphatic carboxylic acids and alcohols include beeswax (a mixture containing myricyl palmitate as a main component), stearyl stearate, behenyl behenate, stearyl behenate, glycerin monopalmitate, glycerin monostearate, glycerin distearate, glycerin tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, and pentaerythritol tetrastearate.

[0055] Examples of aliphatic hydrocarbons having a number average molecular weight of 200 to 15,000 include liquid paraffin, paraffin wax, microcrystalline wax, polyethylene wax, Fischer-Tropsch wax, and α-olefin oligomers having 3 to 12 carbon atoms. Aliphatic hydrocarbons also include alicyclic hydrocarbons. These hydrocarbons may also be partially oxidized. Among these, paraffin wax, polyethylene wax, or a partial oxide of polyethylene wax is preferred, and paraffin wax and polyethylene wax are more preferred. The number average molecular weight of the aliphatic hydrocarbon is preferably 5,000 or less. The aliphatic hydrocarbon may be a single substance, but even if it is a mixture of substances with various constituent components and molecular weights, it is preferable that the main component is within the above range.

[0056] Examples of polysiloxane-based silicone oils include dimethyl silicone oil, methylphenyl silicone oil, diphenyl silicone oil, and fluorinated alkyl silicone oil.

[0057] The release agent may be contained either as one kind or as two or more kinds in any combination and ratio.

[0058] The content of the release agent is preferably 0.1 part by mass or more and preferably 1 part by mass or less, based on 100 parts by mass of the aromatic polycarbonate resin (A). By setting the content of the release agent to be equal to or more than the lower limit of the above range, sufficient releasability effect is easily obtained, and by setting the content of the release agent to be equal to or less than the upper limit of the above range, sufficient hydrolysis resistance is obtained and mold contamination during injection molding is less likely to occur.

[0059] [Other ingredients] The polycarbonate resin composition of the present invention may contain other components other than those described above, as necessary, as long as the desired physical properties are not significantly impaired. Examples of other components include resins other than polycarbonate resins and various resin additives other than those described above. Note that one type of other component may be contained, or two or more types may be contained in any combination and ratio.

[0060] <Other resins> Other resins include, for example, thermoplastic polyester resins such as polyethylene terephthalate resin, polytrimethylene terephthalate resin, and polybutylene terephthalate resin; styrene-based resins such as polystyrene resin, high impact polystyrene resin (HIPS), acrylonitrile-styrene-acrylic rubber copolymer (ASA resin), acrylonitrile-ethylene propylene rubber-styrene copolymer (AES resin), and acrylonitrile-butadiene-styrene copolymer (ABS resin); polyolefin resins such as polyethylene resin and polypropylene resin; polyamide resin; polyimide resin; polyetherimide resin; polyurethane resin; polyphenylene ether resin; polyphenylene sulfide resin; and polysulfone resin. The other resins may be contained either alone or in any combination and ratio of two or more. When other resins are contained, the amount thereof is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, 15 parts by mass or less, 10 parts by mass or less, 7 parts by mass or less, 5 parts by mass or less, 3 parts by mass or less, and particularly preferably 1 part by mass or less, per 100 parts by mass of the aromatic polycarbonate resin (A).

[0061] <Resin additives> Examples of resin additives include flame retardants, flame retardant auxiliaries, impact modifiers, fillers, ultraviolet absorbers, dyes and pigments, antistatic agents, antifogging agents, antiblocking agents, plasticizers, dispersants, antibacterial agents, etc. The resin additives may be contained alone or in any combination of two or more in amounts that do not impair the effects of the present invention.

[0062] [Method for producing polycarbonate resin composition] There are no limitations on the method for producing the polycarbonate resin composition of the present invention, and a wide variety of known methods for producing polycarbonate resin compositions can be used, including a method in which the above-mentioned essential components and other components that are added as needed are premixed using various mixers such as a tumbler or a Henschel mixer, and then melt-kneaded using a mixer such as a Banbury mixer, a roll, a Brabender, a single-screw kneading extruder, a twin-screw kneading extruder, a kneader, etc. When a twin-screw kneading extruder is used, it is preferable to side-feed the recycled carbon fibers. The melt-kneading temperature is not particularly limited, but is usually in the range of 240 to 320°C.

[0063] [Polycarbonate resin composition] The polycarbonate resin composition of the present invention has high dielectric properties and a low dielectric loss tangent, and therefore has a relative dielectric constant of 3.5 or more, preferably 3.6 or more, particularly 3.7 or more, 3.8 or more, 3.9 or more, 4.0 or more, 4.1 or more, and particularly 4.2 or more, and is also preferably 10 or less, particularly 9 or less, 8.5 or less, and particularly 8.0 or less. The dielectric loss tangent is less than 0.03, preferably 0.025 or less, more preferably 0.020 or less, and even more preferably 0.015 or less. The relative permittivity and dielectric loss tangent are values ​​measured at a frequency of 1 GHz by a perturbation method using a cavity resonator. The specific measurement method is as described in the Examples.

[0064] [Molded products] The polycarbonate resin composition is pelletized and then molded into molded articles by various molding methods. Alternatively, the resin can be melt-kneaded in an extruder and directly molded into molded articles without going through the pelletizing process. The shape of the molded article is not particularly limited and can be appropriately selected depending on the use and purpose of the molded article. Examples include a housing, a plate, a rod, a sheet, a film, a cylinder, an annular shape, a circle, an ellipse, a polygonal shape, an irregular shape, a hollow article, a frame, a box, a panel, and the like.

[0065] The method for molding the molded article is not particularly limited, and any conventionally known molding method can be used, such as injection molding, injection compression molding, extrusion molding, profile extrusion, transfer molding, blow molding, gas-assisted blow molding, blow molding, extrusion blow molding, IMC (in-mold coating) molding, rotational molding, multilayer molding, two-color molding, insert molding, sandwich molding, foam molding, pressure molding, etc. Of these, injection molding is particularly preferred.

[0066] Since the polycarbonate resin composition of the present invention is a resin material with high dielectric properties and a low dielectric dissipation factor, molded articles thereof are suitable for various electric and electronic components, and are particularly suitable for, for example, panel components for display devices used in various mobile terminals such as smartphones, tablet-type personal computers, car navigation systems and car audio systems, mobile game consoles, digital cameras, etc., display-related sensors and housings, capacitors and capacitor components, mobile base station components, antenna components, etc. [Example]

[0067] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples and can be practiced with any modifications within the scope of the present invention. The raw material components used in the following Examples and Comparative Examples are as shown in Table 1 below.

[0068] [Table 1]

[0069] (Examples 1 to 12, Comparative Examples 1 to 7, Reference Examples 1 to 6) The components other than the recycled carbon fiber and virgin carbon fiber listed in Table 1 above were blended in the proportions shown in Table 2 below (all parts by mass), and after uniformly mixing in a tumbler mixer, the mixture was fed into the extruder from the barrel upstream of the extruder using a twin-screw extruder (TEM26SX manufactured by Shibaura Machine Co., Ltd.) at a cylinder temperature of 280°C, a screw rotation speed of 180 rpm, and a discharge rate of 15 kg / hr. The recycled carbon fiber and virgin carbon fiber were fed from a side feeder, and melt-kneaded to obtain pellets of a polycarbonate resin composition.

[0070] [Measurement of relative permittivity and dielectric loss tangent] The pellets obtained by the above manufacturing method were dried at 120°C for 4 hours, and then molded into molded articles measuring 100 mm x 100 mm and 2 mm thick using a fan gate mold on an injection molding machine "NEX80III" manufactured by Nissei Plastic Industrial Co., Ltd. Test pieces measuring 1 mm x 2 mm x 100 mm were prepared from the molded articles parallel to the resin flow direction. The relative permittivity and dielectric loss tangent of the test piece at 1 GHz were measured using a cylindrical cavity resonator manufactured by Kanto Electronics Application Development Co., Ltd.

[0071] The results are shown in Table 2 below. In the table, "Ex. n" represents "Example n," "Comp. n" represents "Comparative Example n," and "Ref. n" represents "Reference Example n." In the table, the amount of carbon fiber is the amount of carbon fiber in the resin composition (parts by mass relative to 100 parts by mass of polycarbonate resin (A)).

[0072] [Table 2]

[0073] [Table 3]

[0074] [Table 4]

[0075] [Table 5] [Industrial Applicability]

[0076] The polycarbonate resin composition of the present invention is a polycarbonate resin material having high dielectric properties and a low dielectric loss tangent, and therefore can be particularly suitably used for various electric and electronic equipment parts and the like.

Claims

1. A polycarbonate resin composition characterized by containing 1 part by mass or more and less than 9 parts by mass of recycled carbon fiber (B) per 100 parts by mass of aromatic polycarbonate resin (A), and having a relative dielectric constant of 3.5 or more and a dielectric dissipation factor of less than 0.

03.

2. 2. The polycarbonate resin composition according to claim 1, wherein the recycled carbon fiber (B) contains 20% by mass or less of residual carbonized material derived from the resin.

3. 3. The polycarbonate resin composition according to claim 1, wherein the aromatic polycarbonate resin (A) has a terminal hydroxyl group content of less than 150 ppm by mass.

4. 3. The polycarbonate resin composition according to claim 1, wherein the aromatic polycarbonate resin (A) has a terminal hydroxyl group content of 150 ppm by mass or more.

5. 3. The polycarbonate resin composition according to claim 1, wherein the content of the recycled carbon fibers (B) is 5 parts by mass or more and less than 9 parts by mass per 100 parts by mass of the aromatic polycarbonate resin (A).

6. 3. The polycarbonate resin composition according to claim 1, wherein the content of the recycled carbon fibers (B) is 1 part by mass or more and less than 5 parts by mass per 100 parts by mass of the aromatic polycarbonate resin (A).

7. Pellets of the resin composition according to claim 1 or 2.

8. A molded article made from the resin composition according to claim 1 or 2.

9. A molded article made from the pellets according to claim 7.

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