Semi-aromatic polyamide resin composition and molded article using the same

Abstract

To provide a semi-aromatic polyamide resin composition excellent in mechanical strength, heat resistance, low abrasion properties and extrusion processability.SOLUTION: The semi-aromatic polyamide resin composition contains, based on 100 pts.wt. of a semi-aromatic polyamide (component A) comprising a dicarboxylic acid component mainly composed of terephthalic acid and an aliphatic diamine component mainly composed of 1,10-decanediamine, (B) 0.1 pt.wt. or more and less than 3 pts.wt. of an aliphatic polyamide (component B), (C) 1-20 pts.wt. of a polyethylene-based slidability imparting agent (component C), and (D) 3-50 pts.wt. of wholly aromatic polyamide fibers (component D).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a semi-aromatic polyamide resin composition having excellent mechanical strength, heat resistance, low abrasion properties and extrusion processability, and to a molded article using the same. [Background technology]

[0002] In recent years, semi-aromatic polyamides have been used as sliding components such as gears and bearings in automobiles and electrical and electronic equipment. In particular, sliding component applications such as various gears and bearings require low wear when sliding against mating materials, as they are exposed to continuous or intermittent frictional forces. In recent years, there has been a demand for components that can achieve long life even under harsh environments such as high temperatures and heavy loads, and these components require higher levels of mechanical strength, heat resistance, and low wear than ever before.

[0003] As examples of semi-aromatic polyamide resin compositions with sliding properties, Patent Document 1 discloses a resin composition in which polyamide 10T (a polyamide made from terephthalic acid and 1,10-decanediamine) is mixed with a sliding property-imparting agent, but the resin composition lacks low wear properties under severe environments such as high loads. Patent Document 2 discloses a resin composition in which MXD6 (a polyamide made from adipic acid and metaxylenediamine) is mixed with a sliding property-imparting agent and an aliphatic polyamide, but the low wear properties are insufficient and there is no suggestion that the inclusion of an aliphatic polyamide would improve mechanical strength or heat resistance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5837377 [Patent Document 2] Patent No. 6827815 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a semi-aromatic polyamide resin composition which is excellent in mechanical strength, heat resistance, low abrasion and extrusion processability, and a molded article made from the same. [Means for solving the problem]

[0006] As a result of extensive research into solving the above-mentioned problems, the present inventors discovered that the above-mentioned object can be achieved by blending a semi-aromatic polyamide, which is composed of a dicarboxylic acid component mainly composed of terephthalic acid and a diamine component mainly composed of 1,10-decanediamine, an aliphatic polyamide, a polyethylene-based sliding property imparting agent, and wholly aromatic polyamide fibers in specific proportions, and thus arrived at the present invention.

[0007] That is, the above-mentioned object is achieved by a semi-aromatic polyamide resin composition characterized by containing 100 parts by weight of (A) a semi-aromatic polyamide resin (component A) consisting of a dicarboxylic acid component mainly composed of terephthalic acid and an aliphatic diamine component mainly composed of 1,10-decanediamine, 0.1 parts by weight or more but less than 3 parts by weight of (B) an aliphatic polyamide (component B), 1 to 20 parts by weight of (C) a polyethylene-based sliding property imparting material (component C), and 3 to 50 parts by weight of (D) wholly aromatic polyamide fiber (component D).

[0008] The present invention will be described in detail below.

[0009] (Component A: semi-aromatic polyamide) The component A of the present invention contains a dicarboxylic acid component and a diamine component as constituent components, with the dicarboxylic acid component being primarily composed of terephthalic acid and the diamine component being primarily composed of 1,10-decanediamine. From the viewpoint of heat resistance, the content of terephthalic acid in the dicarboxylic acid component is preferably 80 mol% or more, more preferably 100 mol%. From the viewpoint of improving mechanical properties, the content of 1,10-decanediamine in the diamine component is preferably 80 mol% or more, more preferably 100 mol%. A specific example of component A is PA10T.

[0010] The dicarboxylic acid component may contain a dicarboxylic acid other than terephthalic acid. Examples of dicarboxylic acids other than terephthalic acid include aromatic dicarboxylic acid components such as phthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. The dicarboxylic acid other than terephthalic acid is preferably contained in an amount of 20 mol% or less relative to the total number of moles of raw material monomers, and more preferably is substantially free of such dicarboxylic acid.

[0011] The diamine component may contain diamines other than 1,10-decanediamine. Examples of other diamines include aliphatic diamines such as 1,2-ethanediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, and 1,15-pentadecanediamine; alicyclic diamines such as cyclohexanediamine; and aromatic diamines such as xylylenediamine and benzenediamine. The amount of other diamines other than 1,10-decanediamine is preferably 20 mol% or less of the total moles of the raw material monomers, and more preferably substantially none.

[0012] Component A in the present invention preferably has a melting point higher than 300°C, which may further improve heat resistance. When it has multiple melting points or when two or more types of semi-aromatic polyamides are used, it may have a melting point of 300°C or lower.

[0013] The melting point of component A in the present invention refers to the temperature of an endothermic peak that appears when approximately 10 mg of pellets of semi-aromatic polyamide are sampled and measured using a differential scanning calorimeter in a nitrogen atmosphere, where the temperature is lowered from the molten state to 20°C at a rate of 20°C / min, held for 5 minutes, and then heated at a rate of 20°C / min. However, if two or more endothermic peaks are detected, the peak with the highest temperature is taken as the melting point.

[0014] Component A can be produced by conventionally known methods such as thermal polymerization and solution polymerization. Thermal polymerization is preferred because of its industrial advantages. Examples of thermal polymerization include a method comprising step (i) of obtaining a reaction product from a dicarboxylic acid component and a diamine component, and step (ii) of polymerizing the obtained reaction product.

[0015] Step (i) can be achieved, for example, by mixing a dicarboxylic acid powder with a monocarboxylic acid, heating the mixture to a temperature above the melting point of the diamine but below the melting point of the dicarboxylic acid, and then adding the diamine to the dicarboxylic acid powder and monocarboxylic acid at this temperature, substantially without adding water, so as to maintain the dicarboxylic acid powder. Alternatively, a suspension of molten diamine and solid dicarboxylic acid is stirred and mixed to obtain a mixture, which is then subjected to a reaction between the dicarboxylic acid, diamine, and monocarboxylic acid to form a salt and a polymerization reaction of the resulting salt to form a low-molecular-weight product at a temperature below the melting point of the resulting semi-aromatic polyamide, thereby obtaining a mixture of the salt and the low-molecular-weight product. In this case, crushing can be carried out during the reaction, or the mixture can be removed after the reaction and crushed. The former method is preferred for step (i), as it allows for easier control of the shape of the reaction product.

[0016] In step (ii), for example, the reaction product obtained in step (i) is solid-state polymerized at a temperature below the melting point of the semi-aromatic polyamide to be finally produced, thereby increasing the molecular weight to a predetermined value, thereby obtaining a semi-aromatic polyamide. The solid-state polymerization is preferably carried out in a stream of an inert gas such as nitrogen at a polymerization temperature of 180 to 270°C for a reaction time of 0.5 to 10 hours.

[0017] The reaction apparatus for step (i) and step (ii) is not particularly limited, and any known apparatus may be used. Step (i) and step (ii) may be carried out in the same apparatus or in different apparatuses.

[0018] In producing component A, a polymerization catalyst may be used to increase the efficiency of polymerization. Examples of the polymerization catalyst include phosphoric acid, phosphorous acid, hypophosphorous acid, and salts thereof. The amount of the polymerization catalyst added is usually preferably 2 mol % or less based on the total monomers constituting the semi-aromatic polyamide.

[0019] (Component B: Aliphatic polyamide) Aliphatic polyamides used as component B in the present invention include polyε-capramide (PA6), polytetramethylene adipamide (PA46), polyhexamethylene adipamide (PA66), polyhexamethylene sebacamide (PA610), polyhexamethylene dodecamide (PA612), polyundecamethylene adipamide (PA116), polyundecanamide (PA11), polydodecanamide (PA12), and polyamide copolymers containing at least two different polyamide components, or mixtures thereof. Among these, polyamides with a structural unit containing six or fewer carbon atoms are preferred, with PA6 (nylon 6) and PA66 (nylon 66) being preferred from an economical standpoint. The use of aliphatic polyamides can improve the wear resistance, mechanical strength, and heat resistance of molded articles.

[0020] The relative viscosity of the aliphatic polyamide is not particularly limited and may be appropriately set depending on the purpose. For example, to obtain a thermoplastic resin composition that is easy to mold, the aliphatic polyamide preferably has a relative viscosity of 1.9 to 4.0, more preferably 2.0 to 3.5. If the relative viscosity of the aliphatic polyamide is less than 1.9, some molded articles may lack toughness, leading to a decrease in mechanical properties. Furthermore, if the relative viscosity of the aliphatic polyamide is more than 4.0, the thermoplastic resin composition may be difficult to mold, and the obtained molded article may have poor appearance.

[0021] The content of Component B is 0.1 to less than 3 parts by weight, preferably 0.3 to 2.5 parts by weight, and more preferably 0.5 to 2 parts by weight, per 100 parts by weight of Component A. If the content is less than 0.1 part by weight, the amount of wear during sliding increases, and the mechanical strength and heat resistance decrease. On the other hand, if the content is 3 parts by weight or more, the amount of wear during sliding increases.

[0022] (Component C: Polyethylene-based material that provides sliding properties) The polyethylene-based sliding property imparting agent used as component C in the present invention can be any known agent. The use of a polyethylene-based sliding property imparting agent can improve the low wear and mechanical strength of molded articles. Examples of polyethylenes used as starting materials in producing a polyethylene-based sliding property imparting agent include high-density polyethylene, low-density polyethylene, and ultra-high-molecular-weight polyethylene each having a viscosity-average molecular weight of several tens of thousands or more, polyethylene wax having a viscosity-average molecular weight of several tens of thousands or less, and mixtures of one or more of these. Various known methods can be used to modify polyethylene, including a method in which air is introduced into the polyethylene in a molten state at 140 to 180°C to introduce functional groups through an oxidation reaction; a method in which the polyethylene is suspended or dissolved in a solvent, and then a modifying monomer and a radical polymerization initiator are added and mixed at a temperature typically between 80 and 200°C to perform graft copolymerization; and a method in which the modifying monomer and a radical polymerization initiator are brought into contact with each other while melt-kneading at a temperature above the melting point, e.g., between 180 and 300°C. Examples of modifying monomers include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid, and nadic acid (endo-cis-bicyclo[2.2]hept-5-ene-2,3-dicarboxylic acid). Derivatives thereof include acid halides, esters, amides, imides, and anhydrides, such as malenyl chloride, maleimide, acrylic acid amide, methacrylic acid amide, glycidyl methacrylate, maleic anhydride, citraconic acid anhydride, monomethyl maleate, dimethyl maleate, and glycidyl maleate. Among these, modified polyethylene resins modified with maleic acid, maleic anhydride, or a mixture thereof are preferred, and modified polyethylene resins modified with maleic anhydride are particularly preferred. The use of these preferred modified polyethylene resins may further improve the mechanical strength and low wear properties of molded articles.

[0023] The viscosity average molecular weight (Mv) of component C is preferably in the range of 100,000 to 1,000,000, more preferably 200,000 to 900,000, and particularly preferably 300,000 to 800,000. By using a polyethylene resin in this range, the mechanical strength and low abrasion properties of the molded product may be further improved. The viscosity average molecular weight of component C is calculated from the following general formula (1) using the intrinsic viscosity [η] measured in decacarboxylic acid solvent at 135°C: Mv=5.37×10 4 [η] 1.37 ···(1)

[0024] The content of Component C is 1 to 20 parts by weight, preferably 3 to 18 parts by weight, and more preferably 5 to 15 parts by weight, per 100 parts by weight of Component A. If the content is less than 1 part by weight, the amount of wear during sliding increases and the mechanical strength decreases. If it exceeds 20 parts by weight, the extrusion processability decreases.

[0025] (Component D: fully aromatic polyamide fiber) The wholly aromatic polyamide fiber used as component D in the present invention may be any fiber that falls into the category of so-called wholly aromatic aramid fibers. By using wholly aromatic polyamide fibers, it is possible to ensure both the mechanical strength and heat resistance required for sliding members and to exhibit excellent low wear properties. Examples of wholly aromatic aramid fibers include meta-aramid fibers and para-aramid fibers, and among these, para-aramid fibers are preferred.

[0026] The wholly aromatic polyamide constituting the fiber of the present invention is substantially obtained from one or more aromatic diamines and one or more aromatic dicarboxylic acid halides. However, a condensing agent, such as a triphenyl phosphite and pyridine system, may be added to the one or more aromatic diamines and one or more aromatic dicarboxylic acids. The wholly aromatic polyamide may be either para-type or meta-type, with the para-type being more preferred. Preferred aromatic diamines include p-phenylenediamine, benzidine, 4,4'-diamino-p-terphenyl, 2,7-diaminofluorene, 3,4-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 1,4-bis-(4-aminophenoxy)benzene, 4,4'-bis-(4-aminophenoxy)biphenyl, and 9,10-bis-(4-aminophenyl)anthracene. The aromatic dicarboxylic acid halides are particularly preferably acid chlorides, such as terephthalic acid chloride, 2,6-naphthalenedicarboxylic acid chloride, 4,4'- Examples of aromatic dicarboxylic acids include diphenyldicarboxylic acid chloride and those containing one or more non-reactive functional groups on the aromatic ring, such as lower alkyl groups, lower alkoxy groups, halogeno groups, and nitro groups. Furthermore, examples of aromatic dicarboxylic acids include terephthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4'-diphenyldicarboxylic acid and those containing one or more non-reactive functional groups on the aromatic ring, such as lower alkyl groups, lower alkoxy groups, halogeno groups, and nitro groups. Furthermore, the structure of a wholly aromatic polyamide preferred in the present invention is one whose main skeleton is represented by the following formula:

[0027] [ka]

[0028] (Here, Ar1 and Ar2 represent at least one aromatic residue selected from the group consisting of the following general formulas [I] to [IV]. Ar1 and Ar2 may be the same or different. In addition, some of the hydrogen atoms of these aromatic residues may be substituted with halogen atoms or lower alkyl groups.)

[0029] [ka]

[0030] [ka]

[0031] [ka]

[0032] [ka]

[0033] In particular, when the sum of Ar1 and Ar2 is taken as 100 mol%, the sum of general formula [I] and general formula [II], the sum of general formula [I] and general formula [III], the sum of general formula [I] and general formula [IV], or general formula [I] is preferably 80 mol% or more. More preferably, the sum of general formula [I] and general formula [II], or the sum of general formula [I] and general formula [III] is 80 mol% or more. Even more preferably, the sum of general formula [I] and general formula [II], or the sum of general formula [I] and general formula [III] is 80 mol% or more, and general formula [II] or general formula [III] is 1 to 20 mol%.

[0034] The aromatic polyamide dope used as the spinning solution may be obtained by solution polymerization or by dissolving a separately obtained wholly aromatic polyamide in a solvent, but solution polymerization is preferred. A small amount of inorganic salt may be added as a solubilizer to improve solubility. Examples of such inorganic salts include lithium chloride and calcium chloride.

[0035] As the polymerization solvent or re-dissolving solvent, a generally known aprotic organic polar solvent is used, examples of which include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylpropionamide, N,N-butylamide, N,N-dimethylisobutyramide, N-methylcaprolactam, N,N-dimethylmethoxyacetamide, N-acetylpyrrolidine, N-acetylpiperidine, N-methylpiperidone-2,N,N'-dimethylethyleneurea, N,N'-dimethylpropyleneurea, N,N,N',N'-tetramethylmalonamide, N-acetylpyrrolidone, N,N,N',N'-tetramethylurea, and dimethyl sulfoxide. Further, as the re-dissolving solvent, a strong acid such as concentrated sulfuric acid or methanesulfonic acid can be used.

[0036] Although there is no particular limitation on the degree of polymerization of the wholly aromatic polyamide, a higher degree of polymerization is preferable if it dissolves in a solvent. When the wholly aromatic polyamide is solution-polymerized, the acid component and the diamine component are reacted in a substantially equimolar ratio, but either component can be used in excess to control the degree of polymerization. Furthermore, a monofunctional acid component or an amine component can be used as an end-capping agent.

[0037] When forming a wholly aromatic polyamide into a fiber, a method of wet forming a wholly aromatic polyamide dope is usually used, either by directly discharging the dope into a coagulation bath or by discharging the dope into the coagulation bath via an air gap. A poor solvent for the wholly aromatic polyamide is used in the coagulation bath, and a good solvent is usually added to adjust the coagulation rate so that the solvent of the wholly aromatic polyamide dope does not escape too quickly and cause defects in the wholly aromatic polyamide fiber. In general, it is preferable to use water as the poor solvent and the solvent of the wholly aromatic polyamide dope as the good solvent. The ratio of good solvent / poor solvent is preferably 15 / 85 to 40 / 60, depending on the solubility and coagulation properties of the wholly aromatic polyamide.

[0038] Although such wholly aromatic polyamide fibers are effective regardless of whether they are bundled or not, bundled fibers are preferred because they are easier to handle. Examples of binders for bundling include polyester resins, polyurethane resins, and polyethersulfone resins, with polyester resins being preferred. In the present invention, such wholly aromatic polyamide fibers can be used alone or as a mixture of two or more types.

[0039] The form of such wholly aromatic polyamide fibers is not particularly limited, and any form can be used, but from the viewpoint of handleability during the production of a resin composition, it is preferable that the fibers are twisted. Using a fiber bundle with a large twist number may stabilize the supply of wholly aromatic polyamide fibers to an extruder. The twist number of the wholly aromatic polyamide fibers is preferably 10 to 500 times / m, more preferably 50 to 450 times / m, and even more preferably 100 to 400 times / m.

[0040] The content of component D is 3 to 50 parts by weight, preferably 10 to 40 parts by weight, more preferably 15 to 30 parts by weight, and even more preferably 18 to 27 parts by weight, per 100 parts by weight of component A. If the content of component D exceeds 50 parts by weight, extrusion processability decreases. On the other hand, if the content is less than 3 parts by weight, the amount of wear during sliding increases, and mechanical strength and heat resistance decrease.

[0041] (Other additives) Furthermore, the resin composition of the present invention may contain other thermoplastic resins, and may contain additives such as antioxidants, impact modifiers, plasticizers, organic and inorganic fillers other than component D, flame retardants, colorants, light stabilizers, heat stabilizers, antistatic agents, antiblocking agents, lubricants other than component C, dispersants, flow modifiers, and crystal nucleating agents, as needed, within the scope of the present invention.

[0042] (Production of Resin Composition) Any method can be used to produce the resin composition of the present invention. For example, the components and optionally other components can be premixed, followed by melt-kneading and pelletizing. Examples of premixing methods include a Nauta mixer, a V-blender, a Henschel mixer, a mechanochemical device, and an extrusion mixer. Premixing can also be performed using an extrusion granulator or briquetting machine. After premixing, the components are melt-kneaded in a melt mixer, typically a vented twin-screw extruder, and pelletized using a pelletizer or other device. Other examples of melt mixers include a Banbury mixer, a kneading roll, and a thermostatically stirred vessel. A vented twin-screw extruder is preferred. Alternatively, the components and optionally other components can be fed independently to a melt mixer, typically a twin-screw extruder, without premixing.

[0043] (Regarding molded products) The resin composition of the present invention obtained as described above can be injection molded or extruded to produce various products. Furthermore, it is also possible to directly mold the resin melt-kneaded in an extruder into sheets, films, profile extrusions, and injection-molded articles without first going through the pelletizing process. Injection molding can be performed using not only conventional molding methods but also injection compression molding, injection press molding, gas-assisted injection molding, foam molding (including supercritical fluid injection), insert molding, in-mold coating molding, adiabatic mold molding, rapid heating and cooling mold molding, two-color molding, sandwich molding, and ultra-high-speed injection molding, depending on the purpose. The advantages of these molding methods are widely known. Molding can be performed using either a cold runner or hot runner system. The resin composition of the present invention can also be extruded to produce various profile extrusions and sheets. In extrusion molding, molded articles can be obtained by extruding a round rod and then cutting it into a disk, or by extruding a thick sheet and then punching it into a desired shape. [Effects of the Invention]

[0044] According to the present invention, it is possible to provide a semi-aromatic polyamide resin composition having excellent mechanical strength, heat resistance, low wear and extrusion processability, and a molded article using the same. The molded article obtained from the resin composition of the present invention can be suitably used as a sliding member for use in, for example, the fields of electricity and electronics, semiconductors, automobiles, industrial machinery, office automation equipment and construction. DETAILED DESCRIPTION OF THE INVENTION

[0045] The embodiments of the present invention are those that summarize the preferred ranges of the above-mentioned requirements, and representative examples thereof are described in the following examples, although the present invention is not limited to these embodiments. [Example]

[0046] Hereinafter, the present invention will be described in detail with reference to examples. Physical properties were evaluated by the following methods.

[0047] [Evaluation of Resin Composition] The stability during extrusion was measured as an evaluation of extrusion processability, the specific wear rate as an evaluation of low wear, the tensile strength as an evaluation of mechanical strength, and the deflection temperature under load as an evaluation of heat resistance, all of which were measured by the methods described below.

[0048] (1) Extrusion processability The stability during extrusion was evaluated according to the following criteria. Stable strands during extrusion: 〇 The strands are unstable during extrusion, making pelletization difficult: ×

[0049] (2) Specific wear rate The pellets obtained by the method described below were dried at 130°C for 6 hours and then molded in an injection molding machine (Toshiba Machine Co., Ltd., EC130SXII-4Y) at a cylinder temperature of 330°C and a mold temperature of 130°C to obtain hollow cylindrical test pieces with an outer diameter of 25.6 mm, an inner diameter of 20 mm, and a height of 15 mm according to JIS K7218A. The test pieces were then subjected to friction and wear testing under the same conditions as a test piece made of carbon steel (S45C) at a surface pressure of 0.75 MPa, a sliding speed of 500 mm / s, and a sliding distance of 3000 m using a friction and wear tester (EFM-3-G, Orientec Co., Ltd.). The weight loss of the test pieces after sliding was measured to the nearest 0.1 mg using an electronic balance, and the specific wear rate was calculated using the formula described in JIS K7218A. The test was performed three times, and the average value was used as the specific wear rate of the composition. The specific wear rate was 2.0 x 10 -6 mm 3 / N·m or less.

[0050] (3) Tensile breaking strength The pellets obtained by the method described below were dried at 130°C for 6 hours, and then test pieces were prepared using an injection molding machine (Toshiba Machine Co., Ltd., EC130SXII-4Y) at a cylinder temperature of 330°C and a mold temperature of 130°C. Tensile tests were carried out in accordance with ISO 527-1 and 527-2 at a test temperature of 23°C and a test speed of 5mm / min to measure the tensile breaking strength. The tensile breaking strength must be 70MPa or more.

[0051] (4) Heat deflection temperature (HDT) The pellets obtained using the method described below were dried at 130°C for 6 hours, and then test specimens were prepared using an injection molding machine (Toshiba Machine Co., Ltd., EC130SXII-4Y) at a cylinder temperature of 330°C and a mold temperature of 130°C, and the deflection temperature under load was measured in accordance with ISO 75-1 and 75-2. Heat resistance must be 120°C or higher under a load of 1.8 MPa.

[0052] [Examples 1-11, Comparative Examples 1-6] According to the amounts shown in Tables 1 and 2, components A, B, C, and other components were fed separately into a twin-screw extruder through the first feed port. Here, the first feed port refers to the feed port at the base. Component D was fed separately through the second feed port using a side feeder. For extrusion, a 30 mm diameter vented twin-screw extruder (TEX30α-31.5BW-3V, manufactured by The Japan Steel Works, Ltd.) was used. The extrusion was performed at a screw rotation speed of 200 rpm, a discharge rate of 20 kg / h, and a vent vacuum of 3 kPa to obtain pellets by melt-kneading. The extrusion temperature was 330°C.

[0053] (Component A) A-1: Semi-aromatic polyamide: PA10T (Unitika Ltd.: Xecot XP500) (B component) B-1: Aliphatic polyamide: PA6 (Ube Industries, Ltd.: UBE Nylon 1011FB) B-2: Aliphatic polyamide: PA66 (Ube Industries, Ltd.: UBE Nylon 2015B)

[0054] (C component) C-1: Maleic anhydride modified polyethylene resin obtained in Production Example 1 <Production Example 1> 100 parts by weight of a polyethylene resin mixture consisting of 15% by weight of ultra-high molecular weight polyethylene (Hi-Zex Million 630M, manufactured by Mitsui Chemicals, Inc.) with an intrinsic viscosity of 31 dL / g measured in decalic acid at 135 °C and 85% by weight of polyethylene (Hi-Zex 2200J, manufactured by Prime Polymer Co., Ltd.) with an intrinsic viscosity of 2 dL / g measured in decalic acid at 135 °C, 1 part by weight of maleic anhydride, and 0.07 parts by weight of organic peroxide (Perhexine-25B, manufactured by Nippon Oil & Fats Co., Ltd.) were mixed in a Nauta mixer. The resulting mixture was melt-kneaded in a single-screw extruder (EXT40 mm extruder, manufactured by Isuzu Chemical Engineering Co., Ltd.) set at 250 °C to obtain component C-1. The intrinsic viscosity [η] of the resulting modified polyethylene resin measured in decalic acid at 135 °C was 5.5 dL / g, and the viscosity-average molecular weight Mv was 550,000.

[0055] C-2: Polyethylene resin obtained in Production Example 2 <Production Example 2> 100 parts by weight of a polyethylene resin mixture consisting of 15% by weight of ultra-high molecular weight polyethylene (Hi-Zex Million 630M, manufactured by Mitsui Chemicals, Inc.) with an intrinsic viscosity of 31 dL / g measured in decaphosphoric acid at 135°C and 85% by weight of polyethylene (Hi-Zex 2200J, manufactured by Prime Polymer Co., Ltd.) with an intrinsic viscosity of 2 dL / g measured in decaphosphoric acid at 135°C was mixed in a Nauta mixer, and the resulting mixture was melt-kneaded in a single-screw extruder (EXT40 mm extruder, manufactured by Isuzu Chemical Engineering Co., Ltd.) set at 250°C to obtain component C-2. The intrinsic viscosity [η] of the resulting polyethylene resin measured in decaphosphoric acid at 135°C was 5.5 dL / g, and the viscosity-average molecular weight Mv was 550,000.

[0056] C-3: Oxidized polyethylene wax: Hiwax 310MP (product name) (Mitsui Chemicals, Inc., viscosity average molecular weight approximately 3,000)

[0057] (D component) D-1: Fully aromatic polyamide fiber: T322EH (product name) (Teijin Limited, para-aramid fiber, major diameter 12 μm, average fiber length 3 mm, polyester resin sizing agent, twist count 245 times / m) D-2: Fully aromatic polyamide fiber: T322UR (product name) (Teijin Limited, para-aramid fiber, major diameter 12 μm, average fiber length 3 mm, polyurethane resin sizing agent, twist count 60 times / m)

[0058] [Table 1]

[0059] [Table 2]

[0060] <Examples 1 to 11> Since the resin composition was within the scope of the present invention, it was found to have excellent mechanical strength, heat resistance and low abrasion.

[0061] <Comparative Example 1> Since the content of component B was below the lower limit, the specific wear rate was large, and the tensile strength at break and heat resistance were low.

[0062] <Comparative Example 2> Since the content of component B exceeded the upper limit, the specific wear rate was large.

[0063] <Comparative Example 3> Since the content of the C component was below the lower limit, the specific wear rate was large and the tensile strength at break was low.

[0064] <Comparative Example 4> The C component content exceeded the upper limit, making it impossible to pelletize.

[0065] <Comparative Example 5> Since the content of component D was below the lower limit, the specific wear rate was large, and the tensile strength at break and heat resistance were low.

[0066] <Comparative Example 6> The content of component D exceeded the upper limit, so pelletization was not possible.

Claims

1. A semi-aromatic polyamide resin composition characterized by comprising 100 parts by weight of (A) a semi-aromatic polyamide (component A) consisting of a dicarboxylic acid component having terephthalic acid as a main component and an aliphatic diamine component having 1,10-decanediamine as a main component, and containing 0.1 to 3 parts by weight of (B) nylon 6 and / or nylon 66 (component B), 1 to 20 parts by weight of (C) a polyethylene-based sliding property imparting material (component C), and 3 to 50 parts by weight of (D) wholly aromatic polyamide fiber (component D).

2. 2. The semi-aromatic polyamide resin composition according to claim 1, wherein component C is a modified polyethylene resin having a viscosity average molecular weight of 100,000 to 1,000,000 and modified with at least one compound selected from the group consisting of maleic acid and maleic anhydride.

3. A molded article made from the semi-aromatic polyamide resin composition according to claim 1 or 2.

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