JP2019038918A - Polybutylene terephthalate resin composition and molded article formed of the same - Google Patents

Abstract

To provide a PBT resin composition capable of obtaining a molded article excellent in moldability, flowability, low warpage, weld strength, and heat cycle resistance of a weld part.SOLUTION: A polybutylene terephthalate resin composition contains 18-28 pts.wt. of (B) a styrene copolymer having 10-30 wt.% of a rubber component, 5-14 pts.wt. of (C) an elastomer containing a modified elastomer, and 30-90 pts.wt. of (D) a reinforcement fiber, based on 100 pts.wt. of (A) a polybutylene terephthalate resin containing a polybutylene (terephthalate/isophthalate)copolymer of which an isophthalic acid component content in the total dicarboxylic acid component is 2.5-5 mol%.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.

  Since PBT resin is excellent in the above characteristics, it is often used for box-shaped parts such as vehicle-mounted electrical parts such as sensor covers, ECU cases, door lock housings, and power window motor housings. Many of these electrical components are fitted with resin covers after the electronic parts and gears are installed inside the resin case, so the fit between the case and the cover is important. The resin used has low warpage Is required. As means for improving the warp of the PBT resin, it is common to blend an amorphous resin, glass fiber, filler or the like. However, the general method of reducing warpage has the effect of increasing the rigidity of the resin and speeding up the crystallization of the resin, so there is a trade-off between lower toughness and lower weld strength, and particularly heat cycle resistance is required. Not suitable for products. In addition, in-vehicle electrical components such as those described above are often molded products having a complicated shape (a shape in which a weld portion is likely to be formed) or molded products in which metal parts are inserted in order to exhibit their functions.

  From such a background, the above-described vehicle-mounted electrical component is required to have a material that has not only low warpage but also high weld strength, in particular, heat cycle resistance of the weld portion.

  As a resin composition excellent in weld strength and heat cycle resistance of a weld part, a resin composition obtained by blending a thermoplastic resin, an inorganic filler, a fatty acid metal salt, and an olefin resin has been proposed (for example, Patent Document 1). ). In addition, there has been proposed a resin composition comprising a thermoplastic polyester, an aromatic vinyl resin, an amide compound, a polyhydric alcohol, an epoxy compound, and a fibrous filler (for example, Patent Document 2).

  As a resin composition excellent in low warpage, a resin composition obtained by blending an aromatic vinyl resin, a crystalline resin, and a fibrous filler has been proposed (for example, Patent Document 3). In addition, a resin composition obtained by blending polybutylene terephthalate, a styrene resin, a polyolefin copolymer, a fibrous inorganic filler, and a plate-like inorganic substance has been proposed (for example, Patent Document 4).

  As a resin composition excellent in low warpage and weld strength, a resin composition obtained by blending polybutylene terephthalate, phosphate ester compound, glass fiber, triazine compound, and polycarbonate has been proposed (for example, Patent Document 5). ).

  As a resin composition having excellent fluidity and heat resistance, a resin composition comprising polybutylene terephthalate, polyethylene terephthalate, vinyl resin, phosphate ester, triazine compound, alkaline earth metal compound, and glass fiber has been proposed. (For example, Patent Document 6). In addition, a resin composition obtained by blending a thermoplastic resin, a thermally conductive filler, and a flame retardant has been proposed (for example, Patent Document 7).

JP 2008-163324 A JP 2011-52172 A JP 2017-82047 A Japanese Patent Laid-Open No. 10-60240 JP 2009-96969 A JP 2009-227750 A JP 2009-270709 A

  However, the molded article made of the resin composition described in Patent Document 1 contains a large amount of inorganic filler, and has insufficient moldability and fluidity. Moreover, the molded article which consists of a resin composition of patent document 2 had few compounding quantities of aromatic vinyl-type resin, and its low curvature property was inadequate.

  Molded articles made of the resin compositions described in Patent Documents 3 and 4 have a large blending amount of aromatic vinyl resin and styrene resin, and have insufficient weld strength and heat cycle resistance at the weld. Further, the molded article made of the resin composition described in Patent Documents 5 to 7 contains a flame retardant, and the weld strength and heat cycle resistance of the weld portion are still insufficient.

  Among the molded products, in the case of in-vehicle parts that are fitted with resin covers and cases by screwing, there are many molded products that are provided with holes for screwing by insert molding of the metal collar, and contact the metal collar part Welds occur in the form. When such a molded product is subjected to heat cycle treatment, cracks occur in the welded portion (weakest portion) in contact with the collar portion due to the difference in linear expansion between the metal and the resin, resulting in problems such as reduced airtightness and reduced product strength. There is a case. Particularly in the case of a thin molded product, the PBT resin having a high crystallization rate has a problem that the weld portion has low adhesion, and the weld strength is reduced, and the weld portion is easily cracked by heat cycle treatment. On the other hand, a material specialized in weld strength and heat cycle resistance of the weld part has a problem that moldability, fluidity, and low warpage of a molded product are lowered due to a decrease in crystallization speed and an improvement in toughness. .

  In view of the above problems, the present invention provides a PBT resin composition capable of obtaining a molded product excellent in moldability, fluidity, low warpage, weld strength, and heat cycle resistance of a weld part. Is an issue.

In order to solve the above problems, the present invention has the following configuration.
(1) (A) With respect to 100 parts by weight of a polybutylene terephthalate resin containing a polybutylene (terephthalate / isophthalate) copolymer having an isophthalic acid component content of 2.5 to 5 mol% in all dicarboxylic acid components, (B) 18 to 28 parts by weight of a styrene copolymer having a rubber component of 10 to 30% by weight, (C) 5 to 14 parts by weight of an elastomer containing a modified elastomer, and (D) 30 to 90 parts by weight of reinforcing fiber A polybutylene terephthalate resin composition.
(2) A copolymer obtained by copolymerizing (B-1) acrylonitrile, styrene and glycidyl methacrylate with a styrene-based copolymer (B-1) having a rubber component of 10 to 30% by weight, and (B-2) rubber The polybutylene terephthalate resin composition according to (1), comprising a styrene-based resin containing components.
(3) The glycidyl group-containing copolymer in which the (C) elastomer is a copolymerization component of (C-1) α-olefin and glycidyl ester of α, β-unsaturated acid, (C-2) ethylene and the number of carbon atoms A non-modified ethylene / α-olefin copolymer having a density of 3 to 20 α-olefin as a copolymerization component and having a density of 870 kg / m ³ or less, the (C-1) α-olefin and α, β-unsaturated The glycidyl group-containing copolymer having a glycidyl ester of an acid as a copolymer component and the density of the copolymer (C-2) ethylene and an α-olefin having 3 to 20 carbon atoms as a copolymer component are 870 kg / m ³ or less. (1) or (2), wherein the blending ratio ((C-1) / (C-2)) of the unmodified ethylene / α-olefin copolymer is 25/75 or more and 75/25 or less by weight. Polybutylene terephthalate Resin composition.
(4) Further, (E) 0.7 to 1.5 parts by weight of ethylene bisstearylamide is added to 100 parts by weight of the (A) polybutylene (terephthalate / isophthalate) copolymer. A molded article comprising the polybutylene terephthalate resin composition according to any one of the above.
(5) A molded article comprising the polybutylene terephthalate resin composition according to any one of (1) to (4).
(6) The molded product according to (5), which has a weld portion having a thickness of 3 mm or less.

  The PBT resin composition of the present invention is excellent in moldability and fluidity, and the molded product obtained by molding the resin composition of the present invention is excellent in low warpage, weld strength and heat cycle resistance of the weld part. It is a metal insert molded product having a weld part of the above, and is useful for parts that require heat cycle resistance.

Appearance of box-shaped molded product for warpage measurement in Examples and Comparative Examples 1 is a schematic side view (1) and a schematic plan view (2). Appearance of molded product for heat cycle resistance evaluation of welds in examples and comparative examples 2 is a schematic side view (1) and a schematic plan view (2).

  Polybutylene terephthalate resin is excellent in crystallization characteristics, heat resistance, moldability, chemical resistance and electrical insulation. The polybutylene (terephthalate / isophthalate) copolymer used in the present invention is a copolymer of terephthalic acid, isophthalic acid and 1,4-butanediol, and includes terephthalic acid or an ester-forming derivative thereof, and isophthalic acid. It is obtained by polycondensation of an acid or an ester-forming derivative thereof and butanediol or an ester-forming derivative thereof by a generally known method. Furthermore, other components may be copolymerized. Other copolymer components include dicarboxylic acids other than terephthalic acid and isophthalic acid or ester-forming derivatives thereof, and diols other than butanediol. Examples of the dicarboxylic acid or its ester-forming derivative include naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, adipic acid, sebacic acid, and alkyl esters thereof. Examples of the diol include 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, trimethylene glycol, propylene glycol, hexamethylene glycol, and polyethylene. Examples include glycol, polypropylene glycol, and polytetramethylene glycol.

  (A) (isophthalic acid component content (hereinafter referred to as isophthalic acid content) in the total dicarboxylic acid component of the polybutylene terephthalate resin including the polybutylene (terephthalate / isophthalate) copolymer of the present invention is 2. Here, the total dicarboxylic acid component means the residue of dicarboxylic acid or its ester-forming derivative constituting the polybutylene terephthalate resin, and the isophthalic acid component means polybutylene terephthalate. It means the residue of isophthalic acid or its ester-forming derivative that constitutes the base resin.By blending a small amount of isophthalic acid component as dicarboxylic acid component, the solidification of polybutylene (terephthalate / isophthalate) copolymer is delayed, Improved adhesion at the weld during injection molding. When the isophthalic acid content is less than 2.5 mol%, the weld strength of the molded product and the heat cycle resistance of the weld portion are reduced, and when it exceeds 5 mol%, The moldability is reduced, more preferably 3 to 4 mol%.

  The (A) polybutylene terephthalate resin in the present invention may contain two or more of the aforementioned polybutylene (terephthalate / isophthalate) copolymers, and may contain polybutylene terephthalate and other copolymerized polybutylene terephthalate resins. . When blending two or more polybutylene terephthalate resins, the isophthalic acid content of the entire polybutylene terephthalate resin may be in the above range.

  The (A) polybutylene terephthalate resin 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.

  The method for producing the (A) polybutylene terephthalate resin 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 polybutylene terephthalate resin in terms of mechanical properties, moldability and color tone, and preferably 0.01 to 0.2. A range of parts by weight is more preferred.

  The resin composition of the present invention comprises (B) a styrene copolymer having a rubber component of 10 to 30% by weight. (B) The styrene-based copolymer having a rubber component of 10 to 30% by weight contains an amorphous resin and a rubber component. Therefore, by blending with (A) a polybutylene terephthalate-based resin, low warpage and heat resistance There is an effect of improving both cycle characteristics. (B) A styrene-based copolymer having a rubber component of 10 to 30% by weight includes (B-1) a copolymer obtained by copolymerizing acrylonitrile, styrene and glycidyl methacrylate, and (B-2) a rubber component. It is preferable to include a styrene resin. As described above, when the component (B) includes a plurality of components, for example, when the component (B-1) and the component (B-2) are included, the component (B-1) and the component (B-2) The ratio of the rubber component to the total weight of is 10 to 30% by weight.

  (B-1) A preferable copolymerization amount of glycidyl methacrylate in a copolymer obtained by copolymerizing acrylonitrile, styrene and glycidyl methacrylate is preferably an amount effective for improving compatibility with the component (A). It is preferably 0.1% by weight or more based on a copolymer obtained by copolymerizing styrene and glycidyl methacrylate. When copolymerized in a large amount, there is a problem of decrease in fluidity and gelation. Therefore, it is preferably 20% by weight or less, more preferably 10% by weight or less, and further preferably 5% by weight or less. The copolymerization amount of styrene and acrylonitrile is not particularly limited, but is preferably 50 to 99% by weight of styrene and 50 to 1% by weight of acrylonitrile with respect to the total of styrene and acrylonitrile.

  (B-2) A styrene resin containing a rubber component is obtained by polymerizing a styrene compound or a styrene compound and another compound copolymerizable with the styrene compound in the presence of the rubber component ( Co) polymer. 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.

  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.

  (B-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, and among these, ABS resins and ASA resins are preferably used from the viewpoint of low warpage of molded products and heat cycle resistance of welds.

  (B) The content of the rubber component in the styrene copolymer is determined by measuring the infrared spectrum of the (B) styrene copolymer containing the component (B-1) and the component (B-2), and the rubber component. It can be determined from the peak of origin. (B) Content of the rubber component in a styrene-type copolymer is 10 to 30 weight%. When the rubber component is less than 10% by weight, the heat cycle resistance of the weld part of the molded product is lowered, and when it exceeds 30% by weight, the low warpage property and weld strength of the molded product are lowered.

The modified elastomer used in the present invention is an elastomer having at least one functional group selected from an epoxy group, an acid anhydride group, and a functional group that is a derivative thereof. (A) From the viewpoint of compatibility with the polybutylene terephthalate resin, it is preferable to have an epoxy group. (C) By mix | blending the elastomer containing a modified elastomer, the heat cycle resistance of (A) polybutylene terephthalate-type resin improves. (C) Elastomers containing modified elastomers include (C-1) a glycidyl group-containing copolymer comprising α-olefin and glycidyl ester of α, β-unsaturated acid as copolymerization components, and (C-2) ethylene and carbon. It is preferable to include an unmodified ethylene / α-olefin copolymer having a density of 870 kg / m ³ or less using an α-olefin having 3 to 20 atoms as a copolymerization component.

  (C-1) A glycidyl group-containing copolymer comprising a glycidyl ester of an α-olefin and an α, β-unsaturated acid as a copolymerization component is a glycidyl ester copolymer of an α-olefin and an α, β-unsaturated acid. , And if necessary, a copolymer obtained by copolymerizing an unsaturated monomer copolymerizable therewith. It is preferable to use 60% by weight or more of α-olefin and α, β-unsaturated glycidyl ester in all copolymer components.

  As an alpha olefin, ethylene, propylene, 1-butene, 1-pentene, 1-octene etc. can be mentioned, for example. Two or more of these may be used.

  Examples of the glycidyl ester of α, β-unsaturated acid include glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, and glycidyl itaconate. Two or more of these may be used. Glycidyl methacrylate is preferably used.

  (C-1) The glycidyl group-containing copolymer has a melt flow rate (hereinafter abbreviated as MFR) measured at 190 ° C. and 2160 g load according to ISO 1133: 1997 of 1 g / 10 min to 15 g / 10 min. preferable. By setting the MFR to 1 g / 10 min or more, the fluidity of the polybutylene terephthalate resin composition is further improved, and by setting the MFR to 15 g / 10 min or less, the thermal and thermal shock resistance when an insert molded product is obtained is further improved. To do.

  Examples of the unsaturated monomer copolymerizable with the above components include vinyl esters such as vinyl ethers, vinyl acetate and vinyl propionate, acrylic acid and methacrylate esters such as methyl, ethyl, propyl and butyl, and acrylonitrile. And styrene. Two or more of these may be used.

  Preferable examples of the glycidyl group-containing copolymer having (C-1) α-olefin and glycidyl ester of α, β-unsaturated acid used in the present invention as a copolymerization component include ethylene / glycidyl methacrylate copolymer. Ethylene / glycidyl methacrylate / vinyl acetate copolymer, ethylene / glycidyl methacrylate / acrylic ester copolymer, ethylene / glycidyl acrylate / vinyl acetate copolymer, and the like. Two or more of these may be used. The glycidyl group-containing copolymer is a glycidyl having a glycidyl ester of an α-olefin and an α, β-unsaturated acid as a copolymer component because the cold-heat shock resistance of the insert molded product obtained from the resin composition is further improved. A group-containing binary copolymer is preferred, and specifically, an ethylene / glycidyl methacrylate copolymer is more preferred.

  A particularly preferred ethylene / glycidyl methacrylate copolymer is available, for example, from ARKEMA under the trade name Rotada® AX8840.

(C-2) An unmodified ethylene / α-olefin copolymer having a density of 870 kg / m ³ or less comprising ethylene and an α-olefin having 3 to 20 carbon atoms as a copolymerization component is composed of ethylene and 3 to 3 carbon atoms. 20 α-olefins are copolymerized.

(C-2) An unmodified ethylene / α-olefin copolymer having 3 to 20 carbon atoms and having a density of 870 kg / m ³ or less using ethylene and an α-olefin having 3 to 20 carbon atoms as a copolymerization component Examples of the α-olefin include propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene and 1-decene. 1-butene and 1-octene are particularly preferred.

  A particularly preferred ethylene / 1-butene copolymer is available from Mitsui Chemicals, Inc. under the trade name Toughmer (registered trademark) A0550S.

Further, (C-2) an unmodified ethylene / α-olefin copolymer having a density of 870 kg / m ³ or less using ethylene and an α-olefin having 3 to 20 carbon atoms as a copolymerization component is disclosed in ISO 1133: 1997. Accordingly, the melt flow rate (hereinafter abbreviated as MFR) measured at 190 ° C. and 2160 g load is preferably 0.05 g / 10 min or more and 1.0 g / 10 min or less. By setting the MFR to 0.05 g / 10 min or more, the fluidity of the polybutylene terephthalate resin composition is further improved. By setting the MFR to 1.0 g / 10 min or less, the thermal shock resistance when an insert molded product is obtained. More improved.

(C-1) Glycidyl group-containing copolymer comprising α-olefin and glycidyl ester of α, β-unsaturated acid as copolymerization component and (C-2) ethylene and α-olefin having 3 to 20 carbon atoms Is a weight ratio when blending an unmodified ethylene / α-olefin copolymer having a density of 870 kg / m ³ or less (hereinafter, abbreviated as (C-1) / (C-2)). Is 25/75 or more and 75/25 or less. In the case of 25/75 or more, the weld strength of the molded product and the heat cycle resistance of the weld part are improved, and in the case of 75/25 or less, the deterioration of the moldability and fluidity can be suppressed. 40/60 or more is more preferable. (C-1) Glycidyl group-containing copolymer comprising α-olefin and glycidyl ester of α, β-unsaturated acid as copolymerization component and (C-2) unmodified ethylene / α-olefin copolymer in the above proportion (C-2) component can be finely dispersed in the resin, and the thermal shock resistance of the resulting molded product is improved.

  As the (D) reinforcing fiber used in the present invention, any fibrous material generally used for reinforcing thermoplastic resins can be used. (A) By mix | blending with a polybutylene terephthalate type-resin, shrinkage | contraction when it is set as a molded article can be suppressed and low curvature property can be improved.

  (D) Specific examples of the reinforcing fiber include glass fiber, asbestos fiber, carbon fiber, graphite fiber, metal fiber, potassium titanate whisker, aluminum borate whisker, magnesium whisker, silicon whisker, wollastonite, sepiolite, Examples include asbestos, slag fiber, zonolite, elestadite, 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 (D) reinforcing fibers in the PBT resin composition is preferably 5 or more, more preferably 10 or more, and further preferably 20 or more. In addition, the average fiber length of the (D) reinforcing fiber in a resin composition can be measured with the following method. 10 g of pellets made of the PBT resin composition are heated in air at 550 ° C. for 8 hours to remove the resin component. The remaining glass fibers are observed using an optical microscope at a magnification of 120 times, and the fiber lengths of 1000 or more randomly selected glass fibers are measured. The average fiber length is indicated by ΣL / n. Here, L is the fiber length of one glass fiber, and n is the total number of glass fibers measured. It is a value obtained by dividing the sum of the measured n fiber lengths by the measured number n.

  The (D) 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 is preferably formed by blending (E) ethylene bisstearylamide. (E) Ethylene bisstearyl amide is generally used as a release agent, but (B) has a fluidity improving effect on the styrene-based copolymer. Adhesion can be improved and weld strength can be improved. As (E) ethylene bisstearylamide preferable in the present invention, for example, PALMOWAX EBS-SF manufactured by Palmamide is commercially available.

  In the PBT resin composition of the present invention, the blending amount of (B) the styrene copolymer containing 10 to 30% by weight of the rubber component is 18 to 28 parts by weight with respect to 100 parts by weight of the (A) polybutylene terephthalate resin. Range. (B) If the blending amount of the styrene copolymer having a rubber component of 10 to 30% by weight is less than 18 parts by weight, the low warpage of the molded product is lowered. On the other hand, when the blending amount of the styrene copolymer having 10 to 30% by weight of the rubber component (B) exceeds 28 parts by weight, the moldability and the weld strength of the molded product are deteriorated. 20-26 weight part is more preferable.

  The blending amount of the elastomer containing the (C) modified elastomer in the PBT resin composition of the present invention is in the range of 5 to 14 parts by weight with respect to 100 parts by weight of the (A) polybutylene terephthalate resin. (C) When the blending amount of the elastomer including the modified elastomer is less than 5 parts by weight, the heat cycle resistance of the weld part of the molded product is lowered. On the other hand, when the blending amount of the elastomer including (C) the modified elastomer exceeds 14 parts by weight, the weld strength of the molded product is lowered. 7 to 12 parts by weight is more preferable.

  The blending amount of the (D) reinforcing fiber in the PBT resin composition of the present invention is in the range of 30 to 90 parts by weight with respect to 100 parts by weight of the (A) polybutylene terephthalate resin. (D) The low curvature property of a molded article falls that the compounding quantity of a reinforced fiber is less than 30 weight part. On the other hand, if the blending amount of (D) reinforcing fiber exceeds 90 parts by weight, the fluidity and heat cycle resistance of the welded part of the molded product are lowered. 50-60 weight part is more preferable.

  The blending amount of (E) ethylenebisstearylamide in the PBT resin composition of the present invention is in the range of 0.7 to 1 part by weight with respect to 100 parts by weight of (A) polybutylene terephthalate resin. (E) By making the compounding quantity of ethylene bisstearyl amide 0.7 weight part or more, weld adhesion improves and the weld strength of a molded article improves. On the other hand, when the blending amount of (E) ethylene bisstearylamide is 1.5 parts by weight or less, the amount of gas generated at the time of bleeding out and heating to the molded product surface can be suppressed. Since the generated gas is caught in the weld portion, the weld strength of the molded product does not decrease.

  In addition, 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.

  The PBT resin composition of the present invention has various plasticizers, ultraviolet absorbers, antibacterial agents, stabilizers, mold release agents, lubricants, antistatic agents, good fluidizing agents and the like as long as the effects of the present invention are not impaired. Additives can be blended.

  In the PBT resin composition of the present invention, it is preferable that the components (A) to (D) and, if necessary, other components are uniformly dispersed. 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 beforehand if necessary.

  In addition, as a method of charging each component into the melt-kneader, for example, using a single-screw or twin-screw extruder, (A) a polybutylene terephthalate-based resin from a main charging port installed on the screw base side, (B) A method in which a styrene-based copolymer, (C) an elastomer containing a modified elastomer, and other components are supplied as necessary, and (D) a reinforcing fiber is supplied and melt-kneaded from a sub-inlet installed on the front side of the screw outlet. Can be mentioned.

  The melt kneading temperature is preferably 200 ° C. or higher, and more preferably 240 ° C. or higher in that it is superior in fluidity and mechanical properties. Moreover, 320 degrees C or less is preferable, 300 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 230 ° 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, electrical / electronic members, building members, various containers, daily necessities, household goods and hygiene items. In particular, the PBT resin composition of the present invention is excellent in moldability, flowability, low warpage, weld strength, and heat cycle resistance of the weld part, so that a thin weld part can be obtained. It is suitably used for parts that require heat cycle resistance.

  The term “molded product having a thin weld part” as used herein means a part having a weld part with a thickness of 3 mm or less in a part of the molded product, and further insert-molded so that a metal part is in contact with the weld part. It may be.

  By using the PBT resin composition of the present invention, a molded product excellent in low warpage, weld strength, and heat cycle resistance of the weld portion can be obtained.

  Examples of the molded product having a thin weld portion include automobile parts such as a sensor cover, electric and electronic parts, and more specifically, an electronic throttle sensor, an ECU case, an intake pressure sensor, a rotation sensor, and the like.

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 (A-1) Polybutylene terephthalate resin: “Toraycon” (registered trademark) 1050M (trade name) manufactured by Toray Industries, Inc .: Isophthalic acid component content 0 mol%
(A-2) Polybutylene (terephthalate / isophthalate) copolymer:
A mixture of 65.6 parts by weight of terephthalic acid, 7.3 parts by weight of isophthalic acid, 61.4 parts by weight of 1,4-butanediol, and 0.05 parts by weight of tetrabutyl titanate and 0.04 parts by weight of monobutyltin oxide was used as a catalyst. The reaction vessel equipped with a distillation column and a stirrer was charged, and the temperature was raised from 150 to 235 ° C. over 4 hours under normal pressure to cause esterification. The produced water and tetrahydrofuran were distilled off through a rectifying column to obtain a tetrahydrofuran-containing product. Next, 0.02 part by weight of phosphoric acid as an anti-coloring agent and 0.05 part by weight of tetrabutyl titanate as a polycondensation catalyst were added to the resulting esterification reaction product, and then transferred to a polycondensation reaction can. The pressure was gradually reduced to 67 Pa over 50 minutes, the temperature was raised to 245 ° C. at the same time, and a polycondensation reaction was performed for 2 hours and 50 minutes to obtain a copolymerized polybutylene terephthalate resin having an isophthalic acid content of 10 mol%. The relative viscosity of the obtained copolymer was 26 dl / g.
(B) Styrene copolymer having a rubber component of 10 to 30% by weight (B-1) Copolymer obtained by copolymerizing acrylonitrile, styrene and glycidyl methacrylate: beads obtained by suspension polymerization of acrylonitrile, styrene and glycidyl methacrylate A vinyl copolymer was prepared. The weight ratio of each component of acrylonitrile / styrene / glycidyl methacrylate is 25.5 / 74 / 0.5 (% by weight).
(B-2) Acrylonitrile / butadiene / styrene copolymer: 70% by weight of styrene and 30% by weight of acrylonitrile in the presence of 60 parts by weight of polybutadiene latex (rubber particle diameter of 0.25 μm, gel content of 80%) 40 parts by weight of a monomer mixture consisting of% was emulsion polymerized. 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) Elastomer containing modified elastomer (C-1-1) Glycidyl group-containing copolymer comprising α-olefin and glycidyl ester of α, β-unsaturated acid as copolymerization component: ethylene / glycidyl methacrylate copolymer ( "Rotada" (registered trademark) AX8840 (trade name) manufactured by ARKEMA, MFR: 5 g / 10 min (190 ° C, 2.16 kgf))
(C-1-2) ethylene / methyl acrylate / glycidyl methacrylate copolymer ("ROTADER" (registered trademark) AX8900 (trade name) manufactured by ARKEMA, MFR: 6 g / 10 min (190 ° C, 2.16 kgf))
(C-2-1) Unmodified ethylene / α-olefin copolymer having ethylene and an α-olefin having 3 to 20 carbon atoms and having a density of 870 kg / m ³ or less: ethylene / 1-butene copolymer ( “Tuffmer” (registered trademark) A0550S (trade name) manufactured by Mitsui Chemicals, Inc., MFR: 0.5 g / 10 min (190 ° C., 2.16 kgf)), density: 861 kg / m ³
(C-2-2) Unmodified ethylene / acrylic copolymer having a density of 930 kg / m ³ consisting of ethylene and acrylic: ethylene / butyl acrylate copolymer (“ROTRIL” (registered trademark) 35BA40 (manufactured by ARKEMA) Product name), MFR: 40 g / 10 min (190 ° C., 2.16 kgf)), density: 930 kg / m ³
(D) Reinforcing fiber: manufactured by Nippon Electric Glass, glass fiber ECS03T187 (trade name)
(E) Ethylene bisstearyl amide: “PALMOWAX” (registered trademark) EBS-SF (trade name) manufactured by Palmamide

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

(1) Moldability A small box having the opening shown in FIGS. 1 and 2 under the molding conditions of a cylinder temperature of 260 ° C., a mold temperature of 80 ° C., and a cooling time of 10 seconds using a Nissei Plastic Industrial Injection Molding Machine “PS40”. A molded product (width 30 mm × depth 30 mm × height 30 mm, thickness 1.5 mm) was molded from the side pin gate. 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 “◯”.

(2) Fluidity 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 shape having a thickness of 1 mm and a width of 10 mm for 8 seconds. The length (bar flow flow length) of the obtained strip-shaped molded product was measured. The injection conditions were a cylinder temperature of 260 ° C., a mold temperature of 80 ° C., and an injection pressure of 63 MPa. If the flow length was 100 mm or more, it was judged that the fluidity of the polybutylene terephthalate resin composition was good.

(3) Low warpage Small size having openings as shown in FIGS. 1 and 2 under the molding conditions of cylinder temperature 260 ° C., mold temperature 80 ° C., cooling time 10 seconds, using Nissei Plastic Industrial Injection Molding Machine “PS40”. A box molded product (width 30 mm × depth 30 mm × height 30 mm, thickness 1.5 mm) was molded from the side pin gate. After being left for 24 hours in a 23% x 50% RH atmosphere, using a Mitutoyo 3D dimensional measuring machine (CRYSTA-Apex S776), the amount of collapse of the side of the side facing away from the gate side is measured and molded. The average value of 10 products was taken as the amount of warpage. The smaller the value of the warp amount, the better the low warp property. If the warp amount of the molded product was 0.45 mm or less, the low warp property was judged to be good.

(4) Weld Strength Five ASTM No. 1 weld dumbbells were produced at a two-point side gate using a Nissei Plastic Industrial Injection Molding Machine “PS40”. The injection conditions were a cylinder temperature of 260 ° C., a mold temperature of 80 ° C., an injection time of 10 seconds, a cooling time of 10 seconds, and an injection pressure of a filling lower limit pressure of each resin composition + 10 MPa. The tensile strength of the obtained test piece was measured based on ASTM-D-638. If the tensile strength of the test piece was 40 MPa or more, the weld strength was judged to be good.

(5) Heat cycle resistance of weld part Using Nissei Plastic Industrial Injection Molding Machine “PS40”, cylinder temperature 260 ° C., mold temperature 80 ° C., injection time 10 seconds, cooling time 10 seconds, injection pressure is the resin composition A metal insert molded product (length 53 mm × width 38 mm × height 8 mm, mold thickness 1.5 mm) having a weld part as shown in FIGS. 3 and 4 was molded from a pin gate on the side surface under the molding lower limit pressure of +10 MPa. The obtained molded product was allowed to stand in a 23% × 50% RH atmosphere for 24 hours, and then placed in a cold thermal shock tester (TSV-40st) manufactured by Tabai Espec, and kept at −40 ° C. × 1 hour (including temperature drop time). The condition of holding at 130 ° C. × 1 hour (including the temperature rising time) was operated as one cycle, and the number of cycles until cracks occurred in the weld portion of the molded product was evaluated by visual confirmation. If the number of cycles until cracks were generated was 10 cycles or more, the heat cycle resistance of the molded product weld was judged to be good.

[Examples 1 to 28]
In accordance with the composition shown in Tables 1 and 2, a twin screw extruder (TEM37 manufactured by Toshiba Machine) with a screw diameter of 37 mmφ in which the components (A), (B), (C) and (E) were set to a cylinder temperature of 250 ° C. ), The component (D) was supplied from the side 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 Tables 1 and 2.

  The obtained polybutylene terephthalate resin composition was excellent in moldability and fluidity, and a molded product excellent in low warpage, weld strength, and heat cycle resistance of the weld part could be obtained. As shown in Examples 1 to 4, as the content of the isophthalic acid component in the total dicarboxylic acid component constituting the (A) polybutylene terephthalate resin increases, the weld strength of the molded product and the heat cycle resistance of the weld part are increased. Improved.

As shown in Examples 5 to 8, as the blending amount of the styrene copolymer having 10 to 30% by weight of the rubber component (B) was increased, the low warpage of the molded product was improved. As shown in Examples 9 to 14, as the amount of the rubber component of (B) the styrene-based copolymer is larger and the amount of the elastomer including (C) the modified elastomer is larger, the heat cycle resistance of the welded part of the molded product is larger. Improved. As shown in Example 15, (C) an elastomer containing a modified elastomer was added to (C-1-2) an ethylene / methyl acrylate / glycidyl methacrylate copolymer, (C-2-2) an ethylene and acrylic density. When an unmodified ethylene / acrylic copolymer having a molecular weight of 930 kg / m ³ is used, (C-1) glycidyl group containing α-olefin and glycidyl ester of α, β-unsaturated acid as a copolymerization component When an unmodified ethylene / α-olefin copolymer having a density of 870 kg / m ³ or less comprising a copolymer, (C-2-1) ethylene, and an α-olefin having 3 to 20 carbon atoms is used. However, the heat cycle resistance of the weld part of the molded product was good.

As shown in Examples 16 to 19, a glycidyl group-containing copolymer having (C-1) an α-olefin and a glycidyl ester of an α, β-unsaturated acid as a copolymerization component and (C-2-1) ethylene And the weight ratio (C-1) / (C-2) of the blend of the unmodified ethylene / α-olefin copolymer having a density of 870 kg / m ³ or less and the α-olefin having 3 to 20 carbon atoms The higher the ratio of (C-1), the better the weld strength of the molded product and the heat cycle resistance of the weld part. Furthermore, as shown in Examples 17 and 18, a glycidyl group-containing copolymer comprising (C-1) an α-olefin and a glycidyl ester of an α, β-unsaturated acid as a copolymerization component and (C-2-1) Weight ratio (C-1) / (C-2) of blend of unmodified ethylene / α-olefin copolymer having a density of ethylene and α-olefin having 3 to 20 carbon atoms of 870 kg / m ³ or less Is 25/75 or more and 75/25 or less, the balance between fluidity, low warpage of the molded product, weld strength, and heat cycle resistance of the weld portion was good.

  As shown in Examples 20 to 23, the greater the blending amount of (D) reinforcing fiber, the smaller the warpage of the molded product and the lower the warpage. As shown in Examples 24 to 27, the fluidity improved as the blending amount of (E) ethylenebisstearylamide increased. Further, as shown in Examples 25 and 26, when the blending amount of (E) ethylenebisstearylamide is in the range of 0.7 to 1.5 parts by weight, the more blending amount, the more the weld of the molded product. Strength and heat cycle resistance of the weld were improved. When blended so as to have the composition of Example 28, the balance of moldability, fluidity, low warpage of the molded article, weld strength, and heat cycle resistance of the weld portion was the most excellent.

[Comparative Examples 1 to 10]
Except having changed into the compounding composition shown in Table 3, it carried out similarly to Examples 1-28, and obtained the pellet of the PBT resin composition.

  As shown in Comparative Examples 1 and 2, when the content of the isophthalic acid component in all the dicarboxylic acid components constituting the (A) polybutylene terephthalate resin exceeded 5 mol%, the moldability deteriorated. On the other hand, when the isophthalic acid component content is less than 2.5 mol%, the weld strength of the molded product and the heat cycle resistance of the weld portion are lowered. As shown in Comparative Examples 3 and 4, when the blending amount of the styrene copolymer having 10 to 30% by weight of the (B) rubber component exceeded 28 parts by weight, the moldability and the weld strength of the molded product were lowered. On the other hand, when the blending amount of the (B) styrene copolymer is less than 18 parts by weight, the low warpage property of the molded product is lowered. As shown in Comparative Examples 5 and 6, when the amount of the rubber component of (B) the styrene copolymer exceeded 30% by weight, the low warpage property and weld strength of the molded product were lowered. On the other hand, when the amount of the rubber component of the (B) styrene copolymer is less than 10% by weight, the heat cycle resistance of the welded part of the molded product is lowered. As shown in Comparative Examples 7 and 8, when the blending amount of the elastomer containing (C) the modified elastomer exceeded 14 parts by weight, the weld strength of the molded product was lowered. On the other hand, when the blending amount of the elastomer including (C) the modified elastomer is less than 5 parts by weight, the heat cycle resistance of the welded part of the molded product is lowered. As shown in Comparative Examples 9 and 10, when the blending amount of (D) reinforcing fiber exceeded 90 parts by weight, the fluidity and heat cycle resistance of the welded part of the molded product were lowered. On the other hand, when the blending amount of the (D) reinforcing fiber is less than 30 parts by weight, the low warpage of the molded product is lowered.

a. Sprue / runner b. Small box for warpage evaluation c. Gate d. Warpage amount e. Sprue / runner f. Molded product for evaluating heat cycle resistance of welds (surface)
g. Molded product for evaluation of heat cycle resistance of welds (back side)
h. Insert metal parts i. Weld (dashed line)
j. Gate

Claims (6)

(A) With respect to 100 parts by weight of polybutylene terephthalate resin containing polybutylene (terephthalate / isophthalate) copolymer having an isophthalic acid component content of 2.5 to 5 mol% in all dicarboxylic acid components, (B) 18 to 28 parts by weight of a styrene copolymer having a rubber component of 10 to 30% by weight, (C) 5 to 14 parts by weight of an elastomer containing a modified elastomer, and (D) 30 to 90 parts by weight of reinforcing fiber. Polybutylene terephthalate resin composition. The (B) rubber component is 10 to 30% by weight of a styrene copolymer (B-1) a copolymer obtained by copolymerizing acrylonitrile, styrene and glycidyl methacrylate, and (B-2) a rubber component. The polybutylene terephthalate resin composition according to claim 1, comprising a styrene resin. The (C) elastomer is (C-1) a glycidyl group-containing copolymer comprising an α olefin and a glycidyl ester of an α, β-unsaturated acid as a copolymerization component, and (C-2) ethylene and 3 to 3 carbon atoms. A non-modified ethylene / α-olefin copolymer having a density of 20 α-olefin as a copolymerization component of 870 kg / m ³ or less, and the (C-1) α-olefin and α, β-unsaturated acid The unmodified glycidyl group-containing copolymer containing glycidyl ester as a copolymer component and the (C-2) ethylene and α-olefin having 3 to 20 carbon atoms having a density of 870 kg / m ³ or less as a copolymer component The polybutylene terephthalate according to claim 1 or 2, wherein the blending ratio of the ethylene / α-olefin copolymer ((C-1) / (C-2)) is 25/75 or more and 75/25 or less by weight. Tree Fat composition. The polybutylene according to any one of claims 1 to 3, further comprising 0.7 to 1.5 parts by weight of (E) ethylene bisstearylamide based on 100 parts by weight of the (A) polybutylene terephthalate resin. A molded article comprising a terephthalate resin composition. A molded article comprising the polybutylene terephthalate resin composition according to any one of claims 1 to 4. The molded product according to claim 5, which has a weld portion having a thickness of 3 mm or less.