JP2017165930A - Polybutylene terephthalate resin composition and molded article formed from the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PBT resin composition capable of obtaining a molded article which is excellent in flowability and moldability and is excellent in dimensional accuracy (concentricity) and high temperature toughness.SOLUTION: There is provided a polybutylene terephthalate resin composition which is obtained by blending (D) calcium carbonate of 2-5 pts.wt. and (F) a reinforced fiber of 40-50 pts.wt. with respect to 100 pts.wt. of the total of (A) polybutylene terephthalate of 38-58 pts.wt., (B) polyethylene terephthalate of 6-16 pts.wt. and (C) a styrenic resin of 26-56 pts.wt., where (F) a phosphorous stabilizer of 0.1-1 pts.wt. with respect to 100 pts.wt. of the total of (A) and (B) is contained, a weight ratio of (A) to (B) is 2.6-7.5, (C) is formed from (C-1) a styrenic resin containing no rubber component and (C-2) a styrenic resin containing a rubber component, and a rubber component content in the total amount of (C) is more than 5 wt.% and 45 wt.% or less.SELECTED DRAWING: None

Description

  The present invention relates to a polybutylene terephthalate resin composition and a molded product formed by molding the same.

  Polybutylene terephthalate (hereinafter may be abbreviated as PBT) resin is excellent in electrical properties, chemical resistance, heat resistance, dimensional stability, etc., so various electric / electronic equipment parts, automobiles, trains, Widely used as interior and exterior parts for vehicles such as trains and other general industrial products.

  PBT resin is often used for box-shaped parts such as on-vehicle electrical parts such as ECU cases, door lock housings, and power window motor housings because of its excellent characteristics. Many of these electrical components are fitted with a resin cover after electronic parts or gears are installed inside the resin case, so the fit between the case and the cover is important. The resin used has low warpage. Required. As means for improving the warpability of PBT, it is common to blend amorphous resin, glass fiber, filler and the like. However, in the case of a molded product obtained by simply molding a PBT resin composition to which a technique for reducing warpage is applied, the dimensional accuracy that appears is greatly affected by the composition, the orientation of the fibrous filler, the shape of the part, and the like. Further, a general technique for reducing warpage increases the rigidity of the resin, so that there is a contradiction in reducing toughness, and it is not suitable for products that require toughness (high temperature tensile elongation) at high temperatures.

  As a resin composition excellent in mechanical strength and flame retardancy, for example, a resin comprising an aromatic polycarbonate resin, a polybutylene terephthalate resin, a polyethylene terephthalate resin, a rubbery polymer, an inorganic filler, and an organic phosphate compound A composition has been proposed (for example, Patent Document 1). In addition, there has been proposed a resin composition comprising a thermoplastic resin, a liquid crystal polymer, a phosphorus flame retardant, silicone rubber, a filler, a dispersion aid, and a fluorine resin (for example, Patent Document 2).

  As a resin composition excellent in dimensional accuracy, mechanical strength, and flame retardancy, a resin composition comprising a polyester resin, a styrene resin, a plate-like inorganic filler, a flame retardant, and a fluorine-containing anti-dripping agent has been proposed. (For example, Patent Document 3). In addition, a resin composition comprising a polycarbonate resin, a styrene resin, a polyester resin, an aliphatic polyhydric alcohol, a flame retardant, an inorganic filler, and a fluorine-containing anti-dripping agent has been proposed (for example, Patent Document 4). ).

  As a resin composition excellent in flame retardancy, a resin composition comprising a polyvinyl chloride resin, polytetrafluoroethylene, a phosphorus compound, a plasticizer, and a needle filler has been proposed (for example, Patent Document 5). ).

  As a resin composition excellent in dimensional stability and heat resistance, a resin composition obtained by blending a non-liquid crystalline semi-aromatic polyester, an olefin copolymer, and a filler that transmits laser light has been proposed (for example, patents). Reference 6).

JP 2010-195923 A JP 2005-139248 A JP 2011-236288 A JP 2010-144129 A JP, 2015-110716, A JP 2004-250621 A

  However, all of the molded articles made of the resin compositions described in Patent Documents 1 to 4 and 6 have insufficient operating durability (high temperature toughness) under high temperature conditions. Moreover, since the molded article which consists of the resin composition of patent documents 1-5 contains a flame retardant, the toughness is inadequate, Furthermore, the molded article which consists of the resin composition of patent document 5 is an acicular filler. Therefore, mechanical strength and dimensional accuracy were insufficient.

  Among the molded products, in the case of a vehicle-mounted part having a worm gear or the like inside, a cylindrical shape is often seen in a part of the molded product because a bearing is mounted. In the case of a molded product having a cylindrical portion, and particularly in the case of a molded product formed by integrally molding a housing portion or a part for attaching the housing portion to the cylindrical portion, the fibers in the circumferential direction of the cylindrical portion in the molded product Since the orientation state of the filler is greatly different compared to the portion other than the cylindrical portion in the molded product (for example, the flat portion of the molded product), due to the difference in shrinkage between the parts after taking out from the mold after injection molding, There was a problem that the cylindrical portion is distorted and the dimensional accuracy (coaxiality) of the cylindrical portion is deteriorated. On the other hand, a material specialized in dimensional accuracy has a problem that toughness is lowered due to an improvement in rigidity.

  This invention makes it a subject to provide the PBT resin composition which is excellent in a moldability, can obtain the molded article excellent in dimensional accuracy (coaxiality), and high temperature toughness in view of said subject.

In order to solve the above problems, the present invention has the following configuration.
(D) Carbonate with respect to a total of 100 parts by weight of (A) 38 to 58 parts by weight of polybutylene terephthalate, (B) 6 to 16 parts by weight of polyethylene terephthalate, and (C) 26 to 56 parts by weight of styrene resin. 2 to 5 parts by weight of calcium, and (E) 40 to 50 parts by weight of reinforcing fiber,
0.1 to 1 part by weight of (F) phosphorus stabilizer is added to 100 parts by weight of the total of (A) polybutylene terephthalate and (B) polyethylene terephthalate,
Furthermore, the weight ratio of the (A) polybutylene terephthalate to the (B) polyethylene terephthalate is 2.6 to 7.5, and the (C) styrenic resin is a styrene that does not contain (C-1) a rubber component. Polybutylene terephthalate resin comprising a styrene resin containing a styrene resin and a (C-2) rubber component, wherein the rubber component amount in the total amount of these (C) styrene resin is more than 5% by weight and 45% by weight or less Composition.
(2) Further, 0.1 to 1 part by weight of (G) polyfunctional compound is added to 100 parts by weight of the total of (A) polybutylene terephthalate, (B) polyethylene terephthalate, and (C) styrene resin. The polybutylene terephthalate resin composition according to (1), which is formulated.
(3) A molded article comprising the polybutylene terephthalate resin composition according to (1) or (2).
(4) The molded article according to (3), which is a molded article having a cylindrical portion and a housing portion.

  The PBT resin composition of the present invention is excellent in moldability, and the molded product obtained by molding the resin composition of the present invention is excellent in dimensional accuracy (coaxiality) and high temperature toughness. Therefore, the molded product having a cylindrical portion and a housing portion. Are useful for parts that require dimensional accuracy (coaxiality) of the cylindrical portion and operating durability (high temperature toughness) under high temperature conditions.

(A) is a top view of the molded product for dimensional accuracy (coaxiality) evaluation used by the Example and the comparative example, (b) is a side view of the molded product. (C) is a three-dimensional view of the molded product. (D) is the side view explaining the definition of the dimensional accuracy (coaxiality) of a molded article.

  Polybutylene terephthalate resin is excellent in crystallization characteristics, heat resistance, moldability, chemical resistance and electrical insulation. The (A) polybutylene terephthalate used in the present invention is a polycondensate obtained by polycondensation of terephthalic acid and / or an ester-forming derivative thereof and 1,4-butanediol and / or an ester-forming derivative thereof. It is a coalescence. Examples of ester-forming derivatives of terephthalic acid include alkyl esters of terephthalic acid such as dimethyl terephthalate. Examples of ester-forming derivatives of 1,4-butanediol include alkyl esters of diols such as 1,4-butanediol ester.

  As long as the object of the present invention is not impaired, the terephthalic acid and / or ester-forming derivative thereof may be copolymerized with other dicarboxylic acids and / or ester-forming derivatives thereof, A copolymer of 4-butanediol and / or an ester-forming derivative thereof with another diol and / or an ester-forming derivative thereof may be used. Examples of the dicarboxylic acid or ester-forming derivative thereof used as the copolymerization component include isophthalic acid, adipic acid, oxalic acid, sebacic acid, decanedicarboxylic acid, naphthalenedicarboxylic acid, and alkyl esters thereof. Two or more of these may be used. Examples of the diol used as a copolymerization component or an ester-forming derivative thereof include ethylene glycol, propylene glycol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, decamethylene glycol, and cyclohexanediene. Examples include methanol, cyclohexanediol, long-chain glycols such as polyethylene glycol having a molecular weight of 400 to 6000, poly1,3-propylene glycol, and polytetramethylene glycol, and fatty acid esters thereof. Two or more of these may be used. These copolymer components are preferably 20% by weight or less of the raw material for forming (A) polybutylene terephthalate. Preferred examples of such a copolymer include polybutylene (terephthalate / isophthalate), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene (terephthalate / naphthalate). And poly (butylene / ethylene) terephthalate. Here, “/” represents a copolymer, and the same applies hereinafter. Two or more of these may be blended.

  (A) The polybutylene terephthalate used in the present invention preferably has an intrinsic viscosity in the range of 0.60 to 1.60 when an o-chlorophenol solution is measured at 25 ° C. If the intrinsic viscosity is 0.60 or more, a molded product having excellent mechanical properties can be obtained. 0.70 or more is more preferable. On the other hand, if the intrinsic viscosity is 1.60 or less, the fluidity can be further improved.

  Polyethylene terephthalate resin is excellent in chemical resistance and electrical properties. Further, since the crystallization rate is moderately low, a molded product having excellent mold transferability and good appearance can be obtained. The (B) polyethylene terephthalate used in the present invention is a polymer obtained by polycondensation of terephthalic acid and / or its ester-forming derivative and ethylene glycol and / or its ester-forming derivative. Examples of the ester-forming derivative of terephthalic acid include those exemplified as the components constituting (A) polybutylene terephthalate. Examples of the ester-forming derivatives of ethylene glycol include fatty acid esters such as ethylene glycol fatty acid esters.

  As long as the object of the present invention is not impaired, terephthalic acid or a derivative thereof and ethylene glycol or a derivative thereof may be copolymerized with another dicarboxylic acid and / or an ester-forming derivative thereof, Other diols and / or ester-forming derivatives thereof may be copolymerized. Examples of the dicarboxylic acid or ester-forming derivative thereof used as the copolymer component include those exemplified as the copolymer component constituting (A) polybutylene terephthalate. Examples of the diol or ester-forming derivative thereof used as the copolymerization component include those exemplified as the copolymerization component constituting 1,4-butanediol and (A) polybutylene terephthalate. These copolymer components are preferably 20% by weight or less of the raw material for forming (B) polyethylene terephthalate.

  (B) Preferred examples of polyethylene terephthalate and copolymer include polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sebacate), polyethylene (terephthalate / decanedicarboxylate), polyethylene (terephthalate). / Naphthalate) and the like. Here, “/” indicates a copolymer. Two or more of these may be blended.

  The polyethylene terephthalate resin used in the present invention preferably has an intrinsic viscosity of 0.36 to 1.60 measured at 25 ° C. using an o-chlorophenol solvent, and is in the range of 0.45 to 1.15. Is more preferable. It is suitable from the viewpoint of impact strength and moldability of the resulting composition.

  The production method of (A) polybutylene terephthalate and (B) polyethylene terephthalate used in the present invention is not particularly limited, and examples thereof include known polycondensation methods and ring-opening polymerization methods. Either batch polymerization method or continuous polymerization method can be used, and both ester exchange reaction and polycondensation reaction by direct polymerization can be applied, but the amount of carboxyl end groups can be reduced and fluidity can be improved. The continuous polymerization method is preferable from the viewpoint of increasing the effect, and the direct polymerization method is preferable from the viewpoint of cost.

  In order to effectively advance the esterification reaction or transesterification reaction and polycondensation reaction, it is preferable to add a catalyst during these reactions. Specific examples of the catalyst include organic titanium compounds, tin compounds, zirconia compounds, and antimony compounds. Two or more of these may be used. Among these, organic titanium compounds and tin compounds are preferable. Among organic titanium compounds, tetra-n-propyl ester, tetra-n-butyl ester and tetraisopropyl ester of titanic acid are more preferable, and tetra-n-butyl titanate is preferable. Esters are particularly preferred. Among the tin compounds, dibutyltin oxide, methylphenyltin oxide, and tetraethyltin are preferable. The amount of the catalyst added is preferably in the range of 0.005 to 0.5 parts by weight with respect to 100 parts by weight of the polyethylene terephthalate resin in terms of mechanical properties, moldability and color tone, and 0.01 to 0.2 parts by weight. The range of is more preferable.

  (B) The polyethylene terephthalate preferably includes a polyethylene terephthalate resin that has undergone one process selected from the group consisting of a film molding process, a melt spinning process, and an injection molding process (hereinafter sometimes abbreviated as recycled material). ). Since the polyethylene terephthalate that has undergone these steps receives more heat history than virgin polyethylene terephthalate that has not undergone these steps, the fluidity of the resulting thermoplastic resin composition is improved. Polyethylene terephthalate may be subjected to the above steps a plurality of times or may be subjected to two or more steps, but the more the number of steps and the types of steps, the more the fluidity of the resulting thermoplastic resin composition is improved. . Specifically, there are recycled materials from so-called factories and recycled materials that are consumed after being consumed by general consumers. The former is a production waste during processing, such as injection molding processing, during the polycondensation of PET. Sprue during the process, starting material during the injection molding process or extrusion, or an edge piece of the extruded plate or film. The latter is a plastic article or the like collected and processed after use by the end user. Articles that are widespread in quantity are blow molded PET bottles for mineral water, soft drinks and juices.

  The recycled material may be in the form of a pulverized material or granules, but the recycled material that comes out after being consumed by the consumer is separated and purified, and then melted and granulated in an extruder. This often improves operability, fluidity, and meterability for further processing steps.

  The PBT resin composition of the present invention comprises (C) a styrene resin. The (C) styrenic resin used in the present invention comprises (C-1) a styrene resin not containing a rubber component and (C-2) a styrene resin containing a rubber component. The amount of the rubber component in the total amount is more than 5% by weight and 45% by weight or less, and preferably 15 to 35% by weight. If it is 5% by weight or less, the toughness of the molded product obtained by molding the resin composition is lowered, and if it exceeds 45% by weight, the dimensional accuracy (coaxiality) is lowered. Since it can be set as the molded article which fully demonstrated the characteristic (high temperature toughness) of (C-2) component, the method of using together (C-2) component and (C-1) component is good.

  The (C) styrene resin used in the present invention comprises (C-1) a styrene resin not containing a rubber component and (C-2) a styrene resin containing a rubber component.

  (C-1) The styrenic resin not containing a rubber component is arbitrary as long as it is a (co) polymer having a structural unit derived from styrene, but a styrenic compound, or a styrenic compound and a styrenic compound, (Co) polymers obtained by polymerizing other copolymerizable compounds in the absence of a rubbery polymer are preferred. Specific examples of the styrene compound include styrene, methyl styrene, dimethyl styrene, ethyl styrene, butyl styrene and the like. Two or more of these may be used. Specific examples of other compounds copolymerizable with the styrenic compound include acrylic acid esters such as methyl acrylate, ethyl acrylate, and butyl acrylate, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate, acrylonitrile, and methacrylate. Examples thereof include unsaturated nitrile compounds such as rhonitrile. Two or more of these may be used.

  (C-1) Specific examples of the styrene resin not containing a rubber component include polystyrene, HI (high impact) polystyrene, acrylonitrile / styrene copolymer (AS resin), and among these, dimensional accuracy (coaxial) Degree) and an AS resin which is a copolymer obtained by copolymerizing acrylonitrile and styrene from the viewpoint of moldability. The copolymerization amount of styrene and acrylonitrile in the AS resin is not particularly limited, but is preferably 50 to 1% by weight of acrylonitrile and 50 to 99% by weight of styrene with respect to the total of both.

  (C-2) The styrene resin containing a rubber component is obtained by polymerizing the styrene compound or the styrene compound and another compound copolymerizable with the styrene compound in the presence of the rubber component. (Co) polymers produced.

  As the rubber component, diene rubber, acrylic rubber, ethylene rubber and the like can be used. Specific examples include polybutadiene, poly (butadiene / styrene), poly (butadiene / acrylonitrile), polyisoprene, polymethyl acrylate, polyethyl acrylate, polybutyl acrylate, polyoctyl acrylate, poly (butadiene / butyl acrylate). ), Poly (butadiene / methyl methacrylate), poly (butyl acrylate / methyl methacrylate), poly (butadiene / ethyl acrylate), ethylene / propylene rubber, ethylene / propylene / diene rubber, poly (ethylene / isoprene), poly (Ethylene / methyl acrylate) and the like. These rubber components are used in one kind or a mixture of two or more kinds. Of these rubber components, polybutadiene and polybutyl acrylate are preferably used.

  (C-2) Specific examples of the styrene resin containing a rubber component include acrylonitrile / butadiene / styrene copolymer (ABS resin), acrylonitrile / styrene / acrylate copolymer (ASA resin), acrylonitrile / ethylene rubber / styrene. There are copolymers (AES resins) and the like. Among these, ABS resins and ASA resins are preferably used from the viewpoint of dimensional accuracy (coaxiality) and high temperature toughness.

  (C) The content of the rubber component in the styrene resin is determined by measuring the infrared spectrum of the (C) styrene resin including the components (C-1) and (C-2) and from the peak derived from the rubber component. Can be sought.

  The PBT resin composition of the present invention is obtained by blending (D) calcium carbonate. (D) Since calcium carbonate has small anisotropy, the dimensional accuracy (coaxiality) of the molded product can be greatly reduced. Moreover, (D) calcium carbonate may be processed with 1 or more types of surface treating agents, such as a silane coupling agent, can improve adhesiveness with resin, and can improve the mechanical characteristic of a molded article. (D) The shape of calcium carbonate may be either powder or plate, but is preferably powder, and more preferably powder having a number average particle diameter of 10 μm or less from the viewpoint of dispersibility. Calcium carbonate can be obtained by reacting calcium hydroxide with carbon dioxide. It can also be purchased from Calfine Co., Ltd. under the trade name KSS-1000.

  Reinforcing fibers are excellent in mechanical properties and heat resistance. As the (E) reinforcing fiber used in the present invention, any fibrous material generally used for reinforcing thermoplastic resins can be used. Specifically, glass fiber, asbestos fiber, carbon fiber, graphite fiber, metal fiber, potassium titanate whisker, aluminum borate whisker, magnesium whisker, silicon whisker, wollastonite, sepiolite, asbestos, slag fiber, zonolite , Elastadite, gypsum fiber, silica fiber, silica / alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber and boron fiber. Two or more of these may be blended. In these, glass fiber with higher reinforcement reinforcement | strengthening is preferable. The aspect ratio (average fiber length / average fiber diameter) of the (E) reinforcing fiber in the PBT resin composition is preferably 5 or more, more preferably 10 or more, and further preferably 20 or more. Further, (E) the reinforcing fiber may be coated or focused with a thermoplastic resin such as an ethylene / vinyl acetate copolymer or a thermosetting resin such as an epoxy resin, and a coupling such as aminosilane or epoxysilane. It may be treated with an agent. As the glass fiber subjected to such pretreatment, specifically, as the glass fiber surface-treated with aminosilane (coupling agent) / epoxysilane (bundling agent), for example, CSF3PE941H manufactured by Nittobo Co., Ltd., Japan Electric glass ECS03T187 and the like are commercially available.

  The PBT resin composition of the present invention further comprises (F) a phosphorus stabilizer. The (F) phosphorus stabilizer has the effect of suppressing the transesterification reaction between (A) polybutylene terephthalate and (B) polyethylene terephthalate and improving moldability. Examples of (F) phosphorus stabilizers include phosphite stabilizers (phosphite compounds) and phosphate stabilizers (phosphate compounds). Two or more of these may be used. Among these, phosphate stabilizers are preferable because they have a high effect of improving the moldability of the thermoplastic resin composition. Examples of the phosphite stabilizer include tetrakis [2-t-butyl-4-thio (2′-methyl-4′-hydroxy-5′-t-butylphenyl) -5-methylphenyl] -1,6. -Hexamethylene-bis (N-hydroxyethyl-N-methylsemicarbazide) -diphosphite, tetrakis [2-t-butyl-4-thio (2'-methyl-4'-hydroxy-5'-t-butylphenyl)- 5-methylphenyl] -1,10-decamethylene-di-carboxylic acid-di-hydroxyethylcarbonylhydrazide-diphosphite, tetrakis [2-tert-butyl-4-thio (2'-methyl-4'-hydroxy-5) '-T-butylphenyl) -5-methylphenyl] -1,10-decamethylene-di-carboxylic acid-di-sa Siloylhydrazide-diphosphite, tetrakis [2-tert-butyl-4-thio (2′-methyl-4′-hydroxy-5′-tert-butylphenyl) -5-methylphenyl] -di (hydroxyethylcarbonyl) hydrazide -Diphosphite, tetrakis [2-t-butyl-4-thio (2'-methyl-4'-hydroxy-5'-t-butylphenyl) -5-methylphenyl] -N, N'-bis (hydroxyethyl) And oxamide-diphosphite. It is preferable that at least one PO bond is bonded to an aromatic group, such as tris (2,4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl). ) -4,4′-biphenylenephosphonite, bis (2,4-di-t-butylphenyl) pentaerythritol-di-phosphite, bis (2,6-di-t-butyl-4-methylphenyl) Pentaerythritol-di-phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-di) -Tridecyl) phosphite, 1,1,3-tris (2-methyl-4-ditridecylphosphite-5-t-butyl-phenyl) butane, tris (mixed domo And di - nonylphenyl) phosphite, tris (nonylphenyl) phosphite, 4,4'-isopropylidene-bis (phenyl - dialkyl phosphite), and the like. Two or more of these may be blended. Among them, tris (2,4-di-t-butylphenyl) phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, bis (2,6-di-t-butyl) -4-Methylphenyl) pentaerythritol-di-phosphite, tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylene phosphonite, etc. can be preferably used. Specific product names of these phosphite stabilizers include ADEKA “ADEKA STAB” (registered trademark) PEP-4C, PEP-8, PEP-11C, PEP-24G, PEP-36, HP-10, 2112, 260, 522A, 329A, 1178, 1500, C, 135A, 3010, TPP, “Irgaphos” (registered trademark) 168 of BASF Japan, “Sumilyzer” (registered trademark) P-16 of Sumitomo Chemical, “ Sandstub "(registered trademark) P-EPQ," Weston "(registered trademark) 618, 619G, 624 of GE, etc. are mentioned.

  Examples of the phosphate stabilizer include monostearyl acid phosphate, distearyl acid phosphate, methyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, octyl acid phosphate, isodecyl acid phosphate, and the like. Two or more of these may be blended. Of these, monostearyl acid phosphate and distearyl acid phosphate are preferable. Specific product names of these phosphate stabilizers include “Irganox” (registered trademark) MD1024 from BASF Japan, “Inhibitor” (registered trademark) OABH from Eastman Kodak, and “Adeka Stub” from ADEKA ( (Registered trademark) CDA-1, CDA-6, AX-71, Mitsui Toatsu Fine's "Quunox" (registered trademark), Uniroyal's "Nauguard" (registered trademark) XL-1, and the like.

  The PBT resin composition of the present invention can further contain (G) a polyfunctional compound. By mix | blending a polyfunctional compound, there exists an effect which improves the fluidity | liquidity of a thermoplastic resin composition. Moreover, in the polybutylene terephthalate resin composition of this invention, it is preferable to mix | blend the (G) polyfunctional compound which has a 3 or more functional group. By blending the (G) polyfunctional compound having three or more functional groups, the fluidity of the polybutylene terephthalate resin composition can be further improved. The polyfunctional compound having three or more functional groups may be a low molecular compound or a high molecular weight polymer. Such a polyfunctional compound having three or more functional groups has at least three functional groups selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, a glycidyl group, an isocyanate group, and an amide group. Is preferred. As a preferred example of a polyfunctional compound having three or more functional groups, when the functional group is a hydroxyl group, 1,2,4-butanetriol, 1,2,5-pentanetriol, 1,2,6- Xanthriol, 1,2,3,6-hexanetetrol, glycerin, diglycerin, triglycerin, tetraglycerin, pentaglycerin, hexaglycerin, triethanolamine, trimethylolethane, trimethylolpropane, ditrimethylolpropane, tritrimethylol Propane, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, pentaerythritol, dipentaerythritol, tripentaerythritol, methyl glucoside, sorbitol, mannitol, sucrose, 1,3,5-trihydroxybenzene Polymers such as polyhydric alcohol or a polyvinyl alcohol having a carbon number of 3 to 24 such as 1,2,4-trihydroxy benzene. Among these, glycerin, diglycerin, trimethylolpropane, ditrimethylolpropane, pentaerythritol, and dipentaerythritol having a branched structure are preferable because they are superior in the fluidity of the thermoplastic resin composition. Of these, those having a trivalent or tetravalent hydroxyl group are preferred. More preferably, it has a trivalent hydroxyl group. When the polyfunctional compound having three or more functional groups has a trivalent or tetravalent hydroxyl group, the fluidity of the thermoplastic resin composition is particularly improved.

  Moreover, it is preferable that the (G) polyfunctional compound which has a 3 or more functional group contains one or more alkylene oxide units from a viewpoint of improving the fluidity | liquidity of a thermoplastic resin composition more. Preferred examples of the alkylene oxide unit include aliphatic alkylene oxide units having 1 to 4 carbon atoms. Specific examples include a methylene oxide unit, an ethylene oxide unit, a trimethylene oxide unit, a propylene oxide unit, a tetramethylene oxide unit, A 1,2-butylene oxide unit, a 2,3-butylene oxide unit or an isobutylene oxide unit may be mentioned. In the present invention, it is particularly preferable to use a compound containing an ethylene oxide unit or a propylene oxide unit as an alkylene oxide unit.

  Regarding the number of alkylene oxide units contained in the polyfunctional compound having three or more functional groups used in the present invention, the number of alkylene oxide units per functional group is preferably 0.1 or more and 20 or less. It is more preferably 5 or more and 10 or less, and further preferably 1 or more and 5 or less.

  As a preferred example of a polyfunctional compound having three or more functional groups containing one or more alkylene oxide units, when the functional group is a hydroxyl group, (poly) oxymethylene glycerin, (poly) oxyethylene glycerin, (poly) Oxytrimethylene glycerol, (poly) oxypropylene glycerol, (poly) oxyethylene- (poly) oxypropylene glycerol, (poly) oxytetramethylene glycerol, (poly) oxymethylene diglycerol, (poly) oxyethylene diglycerol, ( Poly) oxytrimethylene diglycerin, (poly) oxypropylene diglycerin, (poly) oxymethylene trimethylolpropane, (poly) oxyethylenetrimethylolpropane, (poly) oxytrimethylenetrimethylolpropane, (poly) oxy Lopylenetrimethylolpropane, (poly) oxyethylene- (poly) oxypropylene trimethylolpropane, (poly) oxytetramethylenetrimethylolpropane, (poly) oxymethyleneditrimethylolpropane, (poly) oxyethyleneditrimethylolpropane, (poly ) Oxytrimethylene ditrimethylolpropane, (poly) oxypropylene ditrimethylolpropane, (poly) oxymethylene pentaerythritol, (poly) oxyethylene pentaerythritol, (poly) oxytrimethylene pentaerythritol, (poly) oxypropylene pentaerythritol, (Poly) oxyethylene- (poly) oxypropylene pentaerythritol, (poly) oxytetramethylene pentaerythritol, (poly) Ximethylenedipentaerythritol, (poly) oxyethylene dipentaerythritol, (poly) oxypropylene trimethylolpropane ether, (poly) oxytrimethylene dipentaerythritol, (poly) oxypropylene dipentaerythritol, (poly) oxymethylene glucose (Poly) oxyethylene glucose, (poly) oxytrimethylene glucose, (poly) oxypropylene glucose, (poly) oxyethylene- (poly) oxypropylene glucose, (poly) oxytetramethylene glucose, and the like. Of these, (poly) oxypropylene trimethylolpropane ether is preferred. Particularly preferred polyfunctional compound (poly) oxypropylene trimethylolpropane ether is available from Nippon Emulsifier Co., Ltd. under the trade name TMP-F32.

  The blending amount of (A) polybutylene terephthalate in the PBT resin composition of the present invention is 38 to 58 with respect to a total of 100 parts by weight of (A) polybutylene terephthalate, (B) polyethylene terephthalate and (C) styrene resin. The range is parts by weight. (A) The fluidity | liquidity of a resin composition and a moldability fall that the compounding quantity of polybutylene terephthalate is less than 38 weight part. 40 parts by weight or more is preferable. On the other hand, when the blending amount of (A) polybutylene terephthalate exceeds 58 parts by weight, the dimensional accuracy (coaxiality) when the resin composition is molded into a molded product is lowered. 55 parts by weight or less is preferable.

  The blending amount of (B) polyethylene terephthalate in the PBT resin composition of the present invention is 6 to 16 weights with respect to a total of 100 parts by weight of (A) polybutylene terephthalate, (B) polyethylene terephthalate and (C) styrenic resin. Part range. (B) When the blending amount of polyethylene terephthalate is less than 6 parts by weight, the dimensional accuracy (coaxiality) when the resin composition is molded into a molded product is lowered. 8 parts by weight or more is preferable. On the other hand, when the blending amount of (B) polyethylene terephthalate exceeds 16 parts by weight, the moldability of the resin composition is lowered. 15 parts by weight or less is preferable.

  Furthermore, the weight ratio of (A) polybutylene terephthalate to (B) polyethylene terephthalate in the PBT resin composition of the present invention is in the range of 2.6 to 7.5. When the weight ratio of (A) polybutylene terephthalate and (B) polyethylene terephthalate is less than 2.6, the moldability of the resin composition is lowered. If it exceeds 7.5, the dimensional accuracy (coaxiality) when the resin composition is molded into a molded product is lowered.

  In the PBT resin composition of the present invention, the blending amount of (C) the styrene resin is 26 to 56 with respect to 100 parts by weight in total of (A) polybutylene terephthalate, (B) polyethylene terephthalate and (C) styrene resin. The range is parts by weight. (C) If the blending amount of the styrene-based resin is less than 26 parts by weight, the dimensional accuracy (coaxiality) when the resin composition is molded into a molded product is lowered. 30 parts by weight or more is preferable. On the other hand, if the blending amount of (C) the styrene resin exceeds 56 parts by weight, the moldability of the resin composition and the dimensional accuracy (coaxiality) when the resin composition is molded into a molded product are lowered. 50 parts by weight or less is preferable. (C) The amount of the rubber component in the styrene resin is in the range of more than 5% by weight and 45% by weight or less. If it is 5% by weight or less, the toughness when the resin composition is molded into a molded product is lowered, and if it exceeds 45% by weight, the dimensional accuracy (coaxiality) is lowered.

  In the PBT resin composition of the present invention, the blending amount of (D) calcium carbonate is 2-5 with respect to a total of 100 parts by weight of (A) polybutylene terephthalate, (B) polyethylene terephthalate, and (C) styrenic resin. Parts by weight. (D) When the blending amount of calcium carbonate is less than 2 parts by weight, the dimensional accuracy (coaxiality) when the resin composition is molded into a molded product is lowered. On the other hand, when the blending amount of (D) calcium carbonate exceeds 5 parts by weight, the fluidity and moldability of the resin composition are lowered. (D) As for the compounding quantity of calcium carbonate, 5 weight part is preferable.

  The blending amount of the (E) reinforcing fiber in the PBT resin composition of the present invention is 40 to 50 weights with respect to a total of 100 parts by weight of (A) polybutylene terephthalate, (B) polyethylene terephthalate, and (C) styrenic resin. Part. (E) When the compounding amount of the reinforcing fiber is less than 40 parts by weight, the dimensional accuracy (coaxiality) when the resin composition is molded into a molded product is lowered. 42 parts by weight or more is more preferable. On the other hand, when the compounding amount of (E) reinforcing fiber exceeds 50 parts by weight, the moldability of the resin composition is lowered. Moreover, since the float of (E) reinforced fiber increases on the surface of the molded product, the surface appearance of the molded product is deteriorated. 48 parts by weight or less is more preferable.

  (F) The compounding quantity of a phosphorus stabilizer is the range of 0.1-1 weight part with respect to a total of 100 weight part of (A) polybutylene terephthalate and (B) polyethylene terephthalate. When the blending amount of the (F) phosphorus stabilizer is less than 0.1 parts by weight, the effect of suppressing the transesterification of (A) polybutylene terephthalate and (B) polyethylene terephthalate cannot be obtained, and the moldability of the resin composition When the resin composition is molded into a molded product, the dimensional accuracy (coaxiality) decreases. On the other hand, if the blending amount of the (F) phosphorus-based stabilizer exceeds 1 part by weight, the reaction between the other additive and the resin is suppressed at the time of molding, so that it is difficult to obtain the effect of the other additive. The dimensional accuracy (coaxiality) when the resin composition is molded into a molded product also decreases.

  (G) When mix | blending a polyfunctional compound, the compounding quantity is 0.1-1 with respect to a total of 100 weight part of (A) polybutylene terephthalate, (B) polyethylene terephthalate, and (C) styrene resin. A range of parts by weight is preferred. (G) The fluidity improvement effect of a resin composition is easy to be acquired as the compounding quantity of a polyfunctional compound is 0.1 weight part or more. (G) When the compounding quantity of a polyfunctional compound is 1 weight part or less, the fall of mechanical strength at the time of shape | molding a resin composition and using it as a molded article can be suppressed.

  Moreover, although the PBT resin composition of this invention contains the reaction material which each component which comprises it reacted, there exists a situation where it is not practical to specify the structure of the said reaction material. Therefore, this invention specifies invention with the compounding quantity of each component.

  In the PBT resin composition of the present invention, various additives such as a plasticizer, an ultraviolet absorber, an antibacterial agent, a stabilizer, a release agent, a lubricant, and an antistatic agent are blended within a range that does not impair the effects of the present invention. be able to.

  In the PBT resin composition of the present invention, the components (A) to (F) and, if necessary, other components are preferably dispersed uniformly. As a method for producing the PBT resin composition of the present invention, for example, a method of melt kneading each component using a known melt kneader such as a single or twin screw extruder, a Banbury mixer, a kneader, or a mixing roll is used. Can be mentioned. Each component may be mixed in advance and then melt kneaded. In addition, it is better that the amount of water contained in each component is small, and it is desirable to dry in advance if necessary.

  In addition, as a method of charging each component into the melt kneader, for example, a single-screw or twin-screw extruder is used, and (A) polybutylene terephthalate, (B) polyethylene terephthalate from a main charging port installed on the screw base side. (C) Styrenic resin, (D) Calcium carbonate, (F) Phosphorus stabilizer and other components as needed, and (E) Reinforcing fiber from the sub-inlet installed on the front side of the screw outlet The method of supplying and melt-kneading is mentioned.

  The melt kneading temperature is preferably 110 ° C. or higher, more preferably 210 ° C. or higher, and further preferably 240 ° C. or higher in terms of being excellent in fluidity and mechanical properties. Moreover, 360 degrees C or less is preferable, 320 degrees C or less is more preferable, and 280 degrees C or less is further more preferable. Here, the melt-kneading temperature refers to the set temperature of the melt-kneader, and for example, in the case of a twin screw extruder, refers to the cylinder temperature.

  The PBT resin composition of the present invention can be processed and used for various molded parts by molding by any method such as known injection molding, extrusion molding, blow molding, press molding, spinning and the like. The temperature at the time of injection molding is preferably 240 ° C. or higher from the viewpoint of further improving fluidity. Examples of molded parts include injection molded parts, extrusion molded parts, blow molded parts, films, sheets, fibers, and the like.

  In the present invention, the above-mentioned various molded products can be used for various applications such as automobile members, electric / electronic members, building members, various containers, daily necessities, household goods and satellite articles. In particular, since the PBT resin composition of the present invention is excellent in fluidity and moldability, and can obtain a molded product excellent in dimensional accuracy (coaxiality) and operating durability (high temperature toughness) under high temperature conditions, It is suitably used for a molded product having a cylindrical portion, particularly a molded product having a cylindrical portion and a housing portion, and further requiring operation durability (high temperature toughness) under high temperature conditions. The "molded product having a cylindrical part and a housing part" here means that the housing part is provided on the side of the cylindrical part other than the opening part of the cylindrical part, and the shape of the housing part is rectangular, triangular, elliptical, etc. Any shape or each composite shape may be sufficient, and the rib may be installed in the housing part. Moreover, you may have the site | part for attaching a cylindrical part and a housing part between a cylindrical part and a housing part, and the shape is any shape, such as a square shape, a triangular shape, an ellipse shape, or each compound shape. The rib may be installed in the site | part for attaching the housing part.

  In a molded product having a cylindrical portion and a housing portion, when an attempt is made to integrally mold the housing portion or the portion for attaching the housing portion to the side surface of the cylindrical portion other than the opening portion of the cylindrical portion, the housing portion or the portion for attaching the housing portion Due to the presence, the inner diameter of the cylindrical portion is likely to be distorted, and the coaxiality of the inner diameter of the cylindrical portion may be deteriorated. Therefore, when the inner diameter of the cylindrical portion is required to be coaxial, a problem may occur due to the distortion. In particular, in the case of a molded product in which a fluid or gas passes through the inside of the cylindrical portion and the flow rate is controlled by a control valve mechanism in the cylindrical portion, the coaxiality of the inner diameter of the cylindrical portion is poor due to distortion generated in the cylindrical portion. Thus, the function of controlling the flow rate of the fluid or gas may be reduced.

  By using the composition of the present invention, even if the housing part or a part for attaching the housing part is integrally formed on the side surface of the cylindrical part other than the opening part of the cylindrical part, the distortion of the inner diameter of the cylindrical part is suppressed. The coaxiality of the inner diameter of the cylindrical portion can be maintained, and when the inner diameter of the cylindrical portion is 30 mm to 100 mm, a molded product having a cylindrical portion and a housing portion with an inner diameter coaxiality of 100 μm or less can be obtained. Furthermore, the obtained molded article has high operating durability (high temperature toughness) under high temperature conditions.

  Examples of the molded product having a cylindrical portion and a housing portion include automobile parts and electric / electronic parts that contain a worm gear, and more specifically, vehicle-mounted power seat gear housings and power window gear housings that contain a worm gear. Can be mentioned.

Hereinafter, the present invention will be described in more detail with reference to examples. Abbreviations and contents of raw materials used in Examples and Comparative Examples are shown below.
(A) Polybutylene terephthalate resin: “Toraycon” (registered trademark) 1050M (trade name) manufactured by Toray Industries, Inc.
(B) Polyethylene terephthalate resin: “Lumirror” (registered trademark) TSB900 (trade name) manufactured by Toray Industries, Inc.
(C-1) Acrylonitrile / styrene copolymer: Suspension polymerization of styrene and acrylonitrile was performed to prepare a bead-like vinyl copolymer. The weight ratio of each component of the acrylonitrile / styrene copolymer is 24/76 (% by weight).
(C-2-1) Acrylonitrile / butadiene / styrene copolymer: polybutadiene latex (rubber particle diameter 0.25 μm, gel content 80%), styrene 70% by weight, acrylonitrile in the presence of 60 parts by weight (in terms of fixed component) 40 parts by weight of a monomer mixture consisting of 30% by weight was subjected to emulsion polymerization. The obtained graft copolymer was coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered and dried to prepare a powdery graft copolymer. The amount of butadiene in the copolymer is 60% by weight.
(C-2-2) Acrylonitrile / styrene / acrylic rubber copolymer: Styrene in the presence of 50 parts by weight (converted to a fixed part) of an acrylic rubbery polymer (rubber particle diameter 0.20 μm, gel content 95%) 50 parts by weight of a monomer mixture consisting of 73.0% by weight and acrylonitrile 27.0% by weight was subjected to emulsion polymerization. The obtained graft copolymer was coagulated with magnesium sulfate, dehydrated and dried to prepare a powdery graft copolymer. The amount of acrylic rubber in the copolymer is 50% by weight.
(D) Calcium carbonate: Calfine KSS-1000 (trade name)
(E) Reinforcing fiber: Nippon Electric Glass, ECS03T187 (trade name)
(F) Phosphorus stabilizer: ADEKA Corporation ADK STAB AX-71 (trade name)
(G) Polyfunctional compound: polyoxypropylene trimethylolpropane ether, manufactured by Nippon Emulsifier TMP-F32 (trade name).

  The evaluation methods in Examples and Comparative Examples are summarized below.

(1) Fluidity (flow length of bar flow)
Using a Nissei Plastic Industrial Injection Molding Machine “PS40”, the polybutylene terephthalate resin composition obtained in each Example and Comparative Example was injected into a strip having a thickness of 1 mm and a width of 10 mm for 8 seconds. The product length (bar flow flow length) was measured. The injection conditions were a cylinder temperature of 270 ° C., a mold temperature of 60 ° C., and an injection pressure of 50 MPa. It can be judged that the fluidity of the polybutylene terephthalate resin composition is better as the flow length is larger.

(2) Moldability Weld dumbbells (ASTM No. 1 type, thickness 3.2 mm) were molded using the Nissei Plastic Industrial Injection Molding Machine “PS40” under the molding conditions of a cylinder temperature of 270 ° C., a mold temperature of 60 ° C., and a cooling time of 20 seconds. did. In the table, “M” indicates that the moldability is poor because the fluidity is poor and cannot be filled, or the test piece is deformed when the molded product is ejected after filling, or the protruding part is greatly cramped. It showed in. After filling, those that do not deform when the molded product protrudes are indicated by “◯”, and those that do not deform when the molded product protrudes even if the cooling time is reduced to 15 seconds are indicated by “「 ”.

(3) High temperature toughness (tensile fracture strain at 80 ° C atmosphere)
A test piece (ISO mold type A) was molded from the polybutylene terephthalate resin composition obtained in each example and comparative example using an injection molding machine “SGE75DU” manufactured by Sumitomo Heavy Industries in accordance with ISO294. In accordance with ISO527-1, 2, an Instron Japan Instron 5581 was used to measure the tensile fracture strain in an 80 ° C. atmosphere (tensile test speed: 5 mm / min, measured between chucks: 115 mm). If the tensile fracture strain in an 80 ° C. atmosphere is 3% or more, it can be judged that the high temperature toughness is good.

(4) Dimensional accuracy (coaxiality)
From the polybutylene terephthalate resin composition obtained in each Example and Comparative Example, a molded product having a cylindrical portion shown in FIG. 1 was molded using an injection molding machine (Sumitomo SE100DU). Molding conditions were a cylinder temperature of 270 ° C., a mold temperature of 60 ° C., a filling time of 0.4 seconds, a holding pressure of 70 MPa, and other conditions were molded under general molding conditions. As shown in FIG. 1D, a cylindrical opening far from the gate was used as a bottom surface, and this bottom surface was used as a reference surface (7 in FIG. 1D). When the perpendicular to the reference plane is lowered from the center of a circle (cylindrical portion) of 5 mm and 20 mm from the end face of the cylindrical opening near the gate, the distance between the intersections of the two perpendiculars on the reference plane (FIG. 1 (d 8) was defined as the coaxiality. The measurement was performed using a Mitutoyo three-dimensional dimension measuring machine. It can be determined that the smaller the coaxiality value, the better the dimensional accuracy. If the coaxiality of the molded product is 0.4 mm or less, it can be determined that the dimensional accuracy is good.

[Examples 1 to 17]
In accordance with the composition shown in Table 1, a twin screw extruder with a screw diameter of 57 mmφ in which the components (A), (B), (C), (D), and (F) were set to a cylinder temperature of 260 ° C. ( The component (E) and the component (G) were supplied from the side from the original loading part of ZSK57) manufactured by WERNER & Pfeiderer, and melt-kneaded. The strand discharged from the die was cooled in a cooling bath and then pelletized with a strand cutter to obtain a polybutylene terephthalate resin composition. The results of evaluating the obtained PBT resin composition by the above method are shown in Table 1.

  The obtained polybutylene terephthalate resin composition was excellent in fluidity and moldability, and a molded product excellent in dimensional accuracy (coaxiality) could be obtained. As shown in Examples 1 to 4, fluidity and moldability were further improved as the blending amount of (A) polybutylene terephthalate increased. On the other hand, as shown in Examples 2 and 4, as the blending amount of (B) polyethylene terephthalate was increased, the dimensional accuracy (coaxiality) of the molded product was improved. As shown in Examples 5 and 6, the fluidity and the dimensional accuracy (coaxiality) of the molded product were improved as the amount of (C) the styrene resin was increased. As shown in Examples 7 and 12, the dimensional accuracy (coaxiality) of the molded product was improved as the blending amount of (D) calcium carbonate was increased. As shown in Examples 8 and 9, the dimensional accuracy (coaxiality) of the molded product was improved as the blending amount of (E) reinforcing fiber was increased. As shown in Examples 10 to 17, the higher the amount of the rubber component contained in (C) the styrene resin, the higher the high temperature toughness (80 ° C. tensile fracture strain) of the molded product. When blended so as to have the compositions of Examples 12 and 16, the balance of fluidity, moldability, high temperature toughness of molded products, and dimensional accuracy (coaxiality) was the most excellent.

[Comparative Examples 1 to 23]
Except having changed into the compounding composition shown in Table 2, it carried out similarly to Examples 1-17, and obtained the pellet of the PBT resin composition. The obtained PBT resin composition was evaluated in the same manner as in Examples 1 to 17, and the results are shown in Table 2.

  As shown in Comparative Examples 1, 2, and 5, when the blending amount of (A) polybutylene terephthalate exceeded 58 parts by weight, the dimensional accuracy (coaxiality) of the molded product was lowered. On the other hand, if the blending amount of (A) polybutylene terephthalate is less than 38 parts by weight, the moldability deteriorated.

  As shown in Comparative Examples 3 and 4, when the blending amount of (B) polyethylene terephthalate exceeds 16 parts by weight, the fluidity and moldability deteriorated. On the other hand, when the blending amount of (B) polyethylene terephthalate is less than 6 parts by weight, the dimensional accuracy (coaxiality) of the molded product is lowered.

  As shown in Comparative Examples 6 and 7, when the blending ratio of (A) polybutylene terephthalate and (B) polyethylene terephthalate exceeded 7.5, the dimensional accuracy (coaxiality) of the molded product was lowered. When the blending ratio of (A) polybutylene terephthalate and (B) polyethylene terephthalate was less than 2.6, fluidity and moldability were lowered.

  As shown in Comparative Examples 8, 9, and 10, when the amount of (C) the styrene resin exceeds 56 parts by weight, the moldability deteriorated. (C) The high temperature toughness (80 degreeC tensile fracture distortion) and the dimensional accuracy (coaxiality) of the molded product fell that the compounding quantity of the styrene resin was less than 26 weight part.

  As shown in Comparative Examples 11, 12, and 13, the blending amount of (D) calcium carbonate is 5% with respect to a total of 100 parts by weight of (A) polybutylene terephthalate, (B) polyethylene terephthalate, and (C) styrenic resin. When it exceeds the part, fluidity and moldability deteriorated. Further, when the blending amount of (D) calcium carbonate is less than 2 parts by weight, the dimensional accuracy (coaxiality) of the molded product is lowered.

  As shown in Comparative Examples 14, 15, and 16, the blending amount of (E) reinforcing fibers was 50 with respect to a total of 100 parts by weight of (A) polybutylene terephthalate, (B) polyethylene terephthalate, and (C) styrene resin. If it exceeds the parts by weight, fluidity and moldability deteriorated. Moreover, the dimensional accuracy (coaxiality) of a molded product fell that the compounding quantity of (E) reinforcement fiber was less than 30 weight part.

  As shown in Comparative Examples 17 and 18, when the amount of the (F) phosphorus stabilizer exceeds 1 part by weight with respect to a total of 100 parts by weight of (A) polybutylene terephthalate and (B) polyethylene terephthalate, And dimensional accuracy (coaxiality) of the molded product decreased. Further, when the blending amount of the (F) phosphorus stabilizer was less than 0.1 parts by weight, the moldability and the dimensional accuracy (coaxiality) of the molded product were lowered.

  As shown in Comparative Examples 19 to 23, when the amount of the rubber component contained in (C) the styrene-based resin was 5% by weight or less, the high temperature toughness (80 ° C. tensile fracture strain) of the molded product was lowered. Moreover, when the amount of the rubber component exceeded 45% by weight, the dimensional accuracy (coaxiality) of the molded product was lowered.

1. Sprue 2. Runner 3. Gate 4. Coaxiality evaluation molded product (cylindrical part)
5. Coaxiality evaluation molded product (housing)
6). Perpendicular to the reference plane, each lowered from the center of a 5 mm or 20 mm circle (cylindrical part) from the end face of the cylindrical opening near the gate
7). Reference plane for coaxiality measurement8. Coaxiality

Claims (4)

(A) 38-58 parts by weight of polybutylene terephthalate,
(B) 6 to 16 parts by weight of polyethylene terephthalate,
(C) For a total of 100 parts by weight of 26 to 56 parts by weight of styrene resin,
(D) 2-5 parts by weight of calcium carbonate;
(E) 40 to 50 parts by weight of reinforcing fiber is blended,
0.1 to 1 part by weight of (F) phosphorus stabilizer is added to 100 parts by weight of the total of (A) polybutylene terephthalate and (B) polyethylene terephthalate,
Furthermore, the weight ratio of the (A) polybutylene terephthalate to the (B) polyethylene terephthalate is 2.6 to 7.5, and the (C) styrenic resin is a styrene that does not contain (C-1) a rubber component. A polybutylene terephthalate resin composition comprising a styrene resin containing a C-type resin and a (C-2) rubber component, wherein the rubber component amount in the total amount of the (C) styrene resin is more than 5% by weight and 45% by weight or less. . Further, 0.1 to 1 part by weight of (G) polyfunctional compound is added to 100 parts by weight of the total of (A) polybutylene terephthalate, (B) polyethylene terephthalate, and (C) styrene resin. The polybutylene terephthalate resin composition according to claim 1. A molded article comprising the polybutylene terephthalate resin composition according to claim 1 or 2. The molded article according to claim 3, which is a molded article having a cylindrical portion and a housing portion.

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