Polyarylene sulfide resin composition and molded article composed of the same

Abstract

To provide a polyarylene sulfide resin composition which is excellent in extrudability and mechanical characteristics, with a reduced amount of mold deposit caused during injection molding.SOLUTION: A polyarylene sulfide resin composition contains 5 to 120 pts.wt. of (B) recycled carbon fiber (component B) to which a sizing agent is at least partially attached, with respect to 100 pts.wt. of (A) a polyarylene sulfide resin (component A). Therein a 5% weight reduction temperature is 460°C or higher in thermal weight-differential thermal analysis measurement of when the temperature is raised at s temperature-raising rate of 5°C / min from room temperature in the air of the component B.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a resin composition comprising a polyarylene sulfide resin and recycled carbon fibers, which has excellent extrudability and mechanical properties and produces little mold deposit during injection molding, and to a molded article comprising the same. [Background technology]

[0002] Polyarylene sulfide resin is an engineering plastic with excellent chemical resistance, heat resistance, and mechanical properties. For this reason, polyarylene sulfide resin is widely used as a metal substitute material in applications such as electrical and electronics, vehicles, aircraft, and housing facilities, taking advantage of its excellent properties. In particular, in recent years, due to the increasing demand for weight reduction, application to components that require high mechanical strength and rigidity has been considered. As a method for improving the mechanical strength and rigidity of polyarylene sulfide resin, a method of filling polyarylene sulfide resin with carbon fiber is known.

[0003] On the other hand, from the viewpoint of effective use of resources, recycling of carbon fibers has been considered. As a method for recovering recycled carbon fibers (r-CF), for example, a method for removing only the matrix resin from carbon fiber reinforced plastic (CFRP) by heating through pyrolysis has been disclosed (see Patent Document 1). Also, Patent Document 2 discloses a resin composition using r-CF. However, r-CF obtained by pyrolysis of CFRP contains residues derived from the matrix resin, and there was a problem that the mold depositability of the resin composition deteriorated compared to the case where virgin carbon fibers were used because the residues decomposed during melt-kneading with the resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5347056 [Patent Document 2] Patent No. 7212816 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a polyarylene sulfide resin composition which is excellent in extrudability and mechanical properties and produces little mold deposit during injection molding, and a molded article made from the same. [Means for solving the problem]

[0006] As a result of intensive research, the present inventors have found that the above-mentioned object can be achieved by blending recycled carbon fibers having a sizing agent attached to at least a portion of a polyarylene sulfide resin, and have arrived at the present invention. That is, the present invention is as follows.

[0007] 1. A polyarylene sulfide resin composition containing 100 parts by weight of (A) polyarylene sulfide resin (component A) and 5 to 120 parts by weight of (B) recycled carbon fibers (component B) having a bundling agent attached to at least a portion of the fibers, wherein the polyarylene sulfide resin composition is characterized in that the 5% weight loss temperature of component B is 460°C or higher in thermogravimetric-differential thermal analysis measurement when the temperature is increased in air from room temperature at a heating rate of 5°C / min. 2. The polyarylene sulfide resin composition according to item 1 above, wherein the sizing agent attached to component B is a polyester-based sizing agent. 3. A polyarylene sulfide resin composition according to item 1 or 2 above, characterized in that component A is a polyarylene sulfide resin obtained by a method in which a diiodoaryl compound, solid sulfur, and a polymerization terminator and / or a polymerization reaction catalyst are polymerized by directly heating without using a polar solvent. 4. (A) A polyarylene sulfide resin (component A) contains 5 to 120 parts by weight of a recycled carbon fiber (component B) to which a sizing agent is at least partially attached, per 100 parts by weight of the polyarylene sulfide resin composition, and the 5% weight loss temperature in the thermogravimetric-differential thermal analysis measurement when the temperature of component B is raised at a rate of 5 °C / min from room temperature in air is 460 °C or higher. A method for producing a polyarylene sulfide resin composition characterized by this. 5. The production method according to item 4 above, characterized in that component A is a polyarylene sulfide resin obtained by a method of directly heating and polymerizing a diiodoaryl compound, solid sulfur, and a polymerization terminator and / or a polymerization reaction catalyst without using a polar solvent. 6. A molded article comprising the polyarylene sulfide resin composition according to any one of items 1 to 3 above.

Effect of the Invention

[0008] According to the present invention, it is possible to provide a polyarylene sulfide resin composition excellent in extrudability and mechanical properties and having less mold deposit during injection molding, and a molded article made therefrom. The molded article made from the polyarylene sulfide resin composition of the present invention can be suitably used, for example, in electric and electronic parts, vehicle-related parts, aircraft parts, industrial machine parts, OA equipment parts, and housing equipment parts.

Mode for Carrying Out the Invention

[0009] Hereinafter, the details of the present invention will be described.

[0010] <Component A: Polyarylene Sulfide Resin> As the polyarylene sulfide resin used as component A of the present invention, any resin belonging to the category called polyarylene sulfide resin may be used.

[0011] Examples of the polyarylene sulfide resin include those composed of a p-phenylene sulfide unit, an m-phenylene sulfide unit, an o-phenylene sulfide unit, a phenylene sulfone unit, a phenylene sulfide ketone unit, a phenylene sulfide ether unit, a diphenylene sulfide unit, a phenylene sulfide unit containing a substituent, a phenylene sulfide unit containing a branched structure, and the like, as its constituent units. Among these, those containing 70 mol % or more, particularly 90 mol % or more of p-phenylene sulfide units are preferred, and further poly(p-phenylene sulfide) is more preferred.

[0012] The terminal functional group of the polyarylene sulfide resin is not particularly limited, but a polyarylene sulfide resin consisting of 10 to 100% by weight of a polyarylene sulfide resin (component A-1) having at least one functional group selected from the group consisting of a hydroxy group, an amino group, and a carboxy group at its terminal and 0 to 90% by weight of a polyarylene sulfide resin (component A-2) not having the above functional group at its terminal is preferred.

[0013] The method for producing the polyarylene sulfide resin is not particularly limited, and polymerization can be performed by a known method, but particularly suitable polymerization methods include those described in U.S. Patent Nos. 4,746,758 and 4,786,713, JP-A-2013-522385, JP-A-2012-233210, and JP-A-5167276, etc. These production methods involve directly heating a diiodoaryl compound and solid sulfur without a polar solvent to polymerize them.

[0014] The method includes an iodization step and a polymerization step. In the iodization step, an aryl compound is reacted with iodine to obtain a diiodoaryl compound. In the subsequent polymerization step, the diiodoaryl compound is polymerized with solid sulfur using a polymerization terminator to produce a polyarylene sulfide resin. Iodine is generated in gas form in this step, which is recovered and reused in the iodization step. Iodine is essentially a catalyst.

[0015] A representative example of solid sulfur used in the above-mentioned preparation method is cyclooctasulfur (S8) in which eight atoms are bonded at room temperature. However, the sulfur compound used in the polymerization reaction is not limited, and any form that is solid or liquid at room temperature can be used.

[0016] Representative diiodoaryl compounds used in the above-mentioned production method include at least one selected from the group consisting of diiodobenzene, diiodonaphthalene, diiodobiphenyl, diiodobisphenol, and diiodobenzophenone. Also, derivatives of iodoaryl compounds to which an alkyl group or a sulfone group is bonded, or to which oxygen or nitrogen is introduced, are used. Iodoaryl compounds are classified into different isomers depending on the bonding position of the iodine atom, and preferred examples of these isomers are compounds in which iodine is symmetrically located at both ends of the molecule of the aryl compound, such as p-diiodobenzene, 2,6-diiodonaphthalene, and p,p'-diiodobiphenyl. The content of the iodoaryl compound is preferably 500 to 10,000 parts by weight based on 100 parts by weight of the solid sulfur. This amount is determined in consideration of the formation of disulfide bonds.

[0017] Representative examples of polymerization terminators used in the above-mentioned production method include monoiodoaryl compounds, benzothiazoles, benzothiazole sulfenamides, thiurams, dithiocarbamates, and aromatic sulfide compounds. Preferred examples of monoiodoaryl compounds include at least one selected from the group consisting of iodobiphenyl, iodophenol, iodoaniline, and iodobenzophenone. Preferred examples of benzothiazoles include at least one selected from the group consisting of 2-mercaptobenzothiazole and 2,2'-dithiobisbenzothiazole. Preferred examples of benzothiazole sulfenamides include at least one selected from the group consisting of N-cyclohexylbenzothiazole 2-sulfenamide, N,N-dicyclohexyl-2-benzothiazole sulfenamide, 2-morpholinothiobenzothiazole, benzothiazole sulfenamide, dibenzothiazole disulfide, and N-dicyclohexylbenzothiazole 2-sulfenamide. A preferred example of the thiurams is at least one selected from the group consisting of tetramethylthiuram monosulfide and tetramethylthiuram disulfide. A preferred example of the dithiocarbamates is at least one selected from the group consisting of zinc dimethyldithiocarbamate and zinc diethyldithiocarbamate. A preferred example of the aromatic sulfide compound is at least one selected from the group consisting of diphenyl sulfide, diphenyl disulfide, diphenyl ether, biphenyl, and benzophenone. In any of the polymerization terminators, one or more functional groups may be substituted on the conjugated aromatic ring skeleton. Examples of the functional group include a hydroxy group, a carboxy group, a mercapto group, an amino group, a cyano group, a sulfo group, and a nitro group, and preferred examples include a hydroxy group, an amino group, and a carboxy group. More preferred examples include a functional group having a peak at 3200 to 3600 cm on the FT-IR spectrum. -1 , 1600~1800cm -1 and 3300-3500 cm -1Examples thereof include a hydroxy group, an amino group, and a carboxy group that indicate peaks. The content of the polymerization terminator is preferably 1 to 30 parts by weight with respect to 100 parts by weight of the solid sulfur. This amount is determined in consideration of the formation of disulfide bonds.

[0018] In the above production method, a polymerization reaction catalyst may be used. Representative examples of the polymerization reaction catalyst include nitrobenzene-based catalysts. Preferred examples among the nitrobenzene-based catalysts include at least one selected from the group consisting of 1,3-diiodo-4-nitrobenzene, 1-iodo-4-nitrobenzene, 2,6-diiodo-4-nitrophenol, iodonitrobenzene, and 2,6-diiodo-4-nitroamine. The content of the polymerization reaction catalyst is preferably 0.01 to 20 parts by weight with respect to 100 parts by weight of the solid sulfur. This amount is determined in consideration of the formation of disulfide bonds.

[0019] By using this polymerization method, it is not substantially necessary to reduce the chlorine content and the sodium content, and a polyarylene sulfide resin excellent in cost performance can be obtained. The polyarylene sulfide resin of the present invention may also contain polyarylene sulfide resins obtained by other polymerization methods.

[0020] <Component B: Recycled carbon fiber to which at least part of the sizing agent is attached> Here, the recycled carbon fiber refers to, for example, carbon fibers recovered from end materials of intermediate products such as prepregs generated from the manufacturing process of CFRP and used CFRP.

[0021] Regarding the method for recovering the recycled carbon fiber, it can be produced by any method, but a method of heating and removing only the matrix resin from CFRP by thermal decomposition is preferred.

[0022] The fiber diameter of the recycled carbon fibers is not particularly limited, but is preferably 2 to 15 μm, and more preferably 3 to 10 μm. Carbon fibers having an average fiber diameter in this range may be able to exhibit good mechanical properties without impairing the appearance of molded products. In addition, it is necessary that a sizing agent is adhered to at least a part of component B. If the sizing agent is not adhered, the recycled carbon fiber will defibrate and the extrudability will decrease significantly.

[0023] Examples of the sizing agent include polyester-based sizing agents, polyamide-based sizing agents, and epoxy-based sizing agents, with polyester-based sizing agents being preferred.

[0024] The amount of the sizing agent attached is preferably 0.5 to 5.0% by weight, and more preferably 1.0 to 3.0% by weight. If the amount of the sizing agent attached is less than 0.5% by weight, the productivity or molding processability may decrease, and if it exceeds 5.0% by weight, the mold deposit property may deteriorate.

[0025] The 5% weight loss temperature of component B, as measured by thermogravimetry-differential thermal analysis when heated in air from room temperature at a heating rate of 5°C / min, must be 460°C or higher, preferably 470°C or higher, and more preferably 475°C or higher. If the 5% weight loss temperature is less than 460°C, mold deposits will be significantly generated during injection molding. There is no particular upper limit to the 5% weight loss temperature, but it is preferably 500°C or lower.

[0026] The content of component B is 5 to 120 parts by weight, preferably 7 to 100 parts by weight, and more preferably 10 to 80 parts by weight, relative to 100 parts by weight of component A. If the content is less than 5 parts by weight, the mechanical properties deteriorate, and if it exceeds 120 parts by weight, the extrudability deteriorates.

[0027] <Other ingredients> The polyarylene sulfide resin composition of the present invention may contain other thermoplastic resins, and may contain various additives, such as antioxidants, impact modifiers, plasticizers, inorganic fillers other than component B, flame retardants, colorants, light stabilizers, heat stabilizers, antistatic agents, antiblocking agents, lubricants, dispersants, flow modifiers, and crystal nucleating agents, as necessary, within the scope of the present invention.

[0028] <Method for producing polyarylene sulfide resin composition> Any method can be used to produce the polyarylene sulfide resin composition of the present invention. For example, each component and optionally other components can be premixed, then melt-kneaded, and pelletized. Premixing means can include a Nauta mixer, a V-type blender, a Henschel mixer, a mechanochemical device, an extrusion mixer, and the like. In premixing, granulation can be performed using an extrusion granulator or a briquetting machine, etc., depending on the case. After premixing, the mixture is melt-kneaded using a melt kneader, typically a vented twin-screw extruder, and pelletized using a pelletizer or other device. Other examples of the melt kneader include a Banbury mixer, a kneading roll, a thermostatic stirring vessel, and the like, but a vented twin-screw extruder is preferred. Alternatively, each component and optionally other components can be independently supplied to a melt kneader, typically a twin-screw extruder, without premixing.

[0029] <About molded products> Molded articles using the polyarylene sulfide resin composition of the present invention can be obtained by molding the pellets produced as described above. Preferably, they are obtained by injection molding or extrusion molding. Injection molding can be performed not only by ordinary molding methods, but also by injection compression molding, injection press molding, gas-assisted injection molding, foam molding (including a method of injecting a supercritical fluid), insert molding, in-mold coating molding, heat-insulating mold molding, rapid heating and cooling mold molding, two-color molding, multi-color molding, sandwich molding, and ultra-high speed injection molding. Molding can be performed by either the cold runner method or the hot runner method. In extrusion molding, a molded article can be obtained by extruding a round bar and then cutting it into a disk shape, or by extruding a thick sheet and then punching it into a desired shape. EXAMPLES

[0030] The present invention will be further described below with reference to examples. In the examples, parts are by weight and % is by weight unless otherwise specified. Evaluations were performed by the following methods.

[0031] [Evaluation of polyarylene sulfide resin composition] (1) Tensile breaking strength The pellets obtained by the method described below were dried at 130°C for 7 hours, and then an ISO 527 Type 1A test piece was prepared using an injection molding machine (EC130SXII-4Y, manufactured by Toshiba Machine Co., Ltd.), and the tensile breaking strength was measured by a method conforming to ISO 527. The larger this value, the more excellent the mechanical properties of the polyarylene sulfide resin composition.

[0032] (2) Mold deposit The pellets obtained by the method described below were dried at 130°C for 7 hours, and then molded into continuous articles using an injection molding machine (PS40E5ASE, manufactured by Nissei Plastic Industrial Co., Ltd.). The degree of dirt in the gas vent of the mold after 200 shots was visually checked. The molding temperature was 320°C. The visual evaluation was made as follows: "Good: dirty area less than 25%", "Good: dirty area 25% to less than 50%", and "Poor: dirty area 50% or more".

[0033] [Examples 1 to 5, Comparative Examples 1 to 4] According to the addition amounts shown in Table 1, Component A was supplied to the twin-screw extruder from the first supply port. Here, the first supply port refers to the supply port at the root. Component B was supplied from the second supply port using a side feeder. For the purpose of assisting the supply of Component B to the twin-screw extruder, a part of Component A was supplied from the second supply port using a side feeder. Extrusion was carried out using a vent-type twin-screw extruder with a diameter of 30 mm Φ (manufactured by Japan Steel Works, Ltd.: TEX30α-31.5BW-2V) at a screw rotation speed of 200 rpm, a discharge rate of 16 kg / h, and a vent vacuum degree of 3 kPa to obtain pellets. The extrusion temperature was 320 °C. In Comparative Examples 2 and 4, Component B shot up and pellets could not be produced.

[0034] Each component with the symbol notation in Table 1 is as follows. <Component A> A-1: Polyarylene sulfide resin obtained by the following production method [Production Method 1] A thermocouple capable of measuring the internal temperature of the reactor, a 5L reactor with a vacuum line that can be filled with nitrogen and evacuated, was charged with 5130 g of p-diiodobenzene (p-DIB), 450 g of sulfur, and 4 g of 1,3-diiodo-4-nitrobenzene mercaptobenzothiazole as a reaction initiator. The reactants were heated to 180 °C to completely melt and mix, and then starting from the initial reaction conditions of 220 °C and 350 Torr, the polymerization reaction was allowed to proceed while gradually increasing the temperature and decreasing the pressure in steps until the final reaction temperature reached 300 °C and the pressure was 1 Torr or less. When the polymerization reaction had proceeded 80% (the degree of progress of the polymerization reaction was determined by measuring the relative ratio of the current viscosity to the target viscosity [(current viscosity / target viscosity)×100(%)]. The current viscosity was measured with a viscometer after sampling a sample during the polymerization process.), 60 g of 2,2'-dithiobisbenzothiazole was added as a polymerization terminator, and the reaction was allowed to proceed for 10 minutes under a nitrogen atmosphere. Then, the vacuum was gradually increased to 0.5 Torr or less until the target viscosity was reached, and then the reaction was terminated to synthesize a polyarylene sulfide resin having a phenyl group at the main chain end. The resin after the reaction was produced in pellet form using a small strand cutter machine. The weight average molecular weight was 72,000. A-2: Polyarylene sulfide resin (manufactured by Solvay: Ryton QA281N (product name))

[0035] <Component B> B-1: Recycled carbon fiber (manufactured by Carbon Fiber Recycling Co., Ltd.: T8S103CD0R (product name), polyester-based sizing agent (adhesion amount: 2% by weight), 5% weight loss temperature 483 °C) B-2 (comparative example): Recycled carbon fiber (manufactured by Carbon Fiber Recycling Co., Ltd.: T8S103CD0E (product name), epoxy-based sizing agent (adhesion amount: 2% by weight), 5% weight loss temperature 457 °C) B-3 (comparative example): Recycled carbon fiber without a sizing agent attached, produced by pyrolyzing CFRP (5% weight loss temperature 487 °C)

[0036]

Table 1

Claims

1. A polyarylene sulfide resin composition comprising 100 parts by weight of (A) polyarylene sulfide resin (component A) and 5 to 120 parts by weight of (B) recycled carbon fibers having a sizing agent attached to at least a portion thereof (component B), wherein the polyarylene sulfide resin composition is characterized in that the 5% weight loss temperature of component B is 460°C or higher in thermogravimetric-differential thermal analysis measurement when the temperature is increased in air from room temperature at a heating rate of 5°C / min.

2. 2. The polyarylene sulfide resin composition according to claim 1, wherein the sizing agent attached to the component B is a polyester-based sizing agent.

3. The polyarylene sulfide resin composition according to claim 1 or 2, characterized in that component A is a polyarylene sulfide resin obtained by a method in which a diiodoaryl compound, solid sulfur, and a polymerization terminator and / or a polymerization reaction catalyst are polymerized by directly heating without using a polar solvent.

4. A method for producing a polyarylene sulfide resin composition, comprising 100 parts by weight of (A) polyarylene sulfide resin (component A) and 5 to 120 parts by weight of (B) recycled carbon fibers (component B) having a sizing agent attached to at least a portion thereof, wherein component B has a 5% weight loss temperature of 460°C or higher in thermogravimetric-differential thermal analysis measurement when heated in air from room temperature at a heating rate of 5°C / min.

5. The method according to claim 4, characterized in that component A is a polyarylene sulfide resin obtained by a method of polymerizing a diiodoaryl compound, solid sulfur, and a polymerization terminator and / or a polymerization catalyst by directly heating without using a polar solvent.

6. A molded article comprising the polyarylene sulfide resin composition according to claim 1 or 2.

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