JP2006291100A - Polybutylene terephthalate resin composition and molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polybutylene terephthalate (PBT) resin composition excellent in alkali resistance.
SOLUTION: A PBT resin containing at least a PBT copolymer, 1 to 30 parts by weight of a polyolefin-modified polysiloxane, and 5 to 80 parts by weight of a filler or reinforcement with respect to 100 parts by weight of the PBT resin. A PBT resin composition is composed of a material (such as a glassy filler). The polyolefin-modified polysiloxane may be composed of a polyorganosiloxane and an olefin resin grafted on the polyorganosiloxane. The resin composition may further contain an elastomer (such as a styrene elastomer and / or an olefin elastomer). Such a resin composition is useful for forming a molded article. The molded product may have a weld part at least partially, and may have at least one selected from an insert part, a press-fit part, and a screw part.
[Selection figure] None

Description

  The present invention relates to a polybutylene terephthalate resin composition excellent in alkali resistance, and a molded article using the same.

  Polybutylene terephthalate (PBT) resin is excellent in various properties such as heat resistance, chemical resistance, electrical properties, mechanical properties, and molding processability.・ It is used for a wide range of applications including electronic devices. Specific applications include various automotive electrical parts (various control units, various sensors, ignition coils, etc.), connectors, switch parts, relay parts, coil parts, and the like.

  However, the PBT resin has a relatively low long-term durability against an alkaline solution, and the usage environment and usage are limited. For example, depending on the use of the resin molded product, it may be used in contact with chemicals such as a toilet cleaner, a bathroom cleaner, a bleaching agent, and a snow melting agent. And such a chemical | medical agent contains sodium hydroxide, sodium hypochlorite, sodium percarbonate, calcium chloride etc. as a structural component. Therefore, the resin molded product is exposed to an alkaline atmosphere (in some cases, frequently repeated). In particular, if the resin molded product is excessively strained due to screw tightening, metal press fitting, caulking, etc., and exposed to an alkali atmosphere as described above for a long time or frequently, both the strain and the alkali component As a result, so-called environmental stress cracking occurs and cracks occur in the molded product.

  Therefore, PBT resin compositions with improved alkali resistance are also being studied. Japanese Patent Application Laid-Open No. 2002-356611 (Patent Document 1) discloses a polybutylene terephthalate resin (A) containing 30 to 95 parts by weight of a polybutylene terephthalate / isophthalate copolymer, and (B) 1 to 30 parts by weight of a polycarbonate resin. A polyester resin composition comprising 1 to 30 parts by weight of (C) elastomer, 3 to 60 parts by weight of (D) fibrous reinforcing material, and the total amount of (A) to (D) is 100 parts by weight. It is disclosed that it is excellent in alkalinity. However, although the resin composition can reduce the occurrence of cracks in the weld part to some extent, the resin composition contains a polycarbonate resin that is inferior in alkali resistance to PBT, and therefore has insufficient alkali resistance.

  In addition, International Publication WO00 / 078867 (Patent Document 2) includes (A) a thermoplastic polyester resin, (B) 1 to 25% by weight of an impact resistance imparting agent, (C) a silicone-based compound and / or a fluorine-based compound. 0.1 to 15% by weight of compound, (D) 1 to 50% by weight of inorganic filler, and (E) 0.1 to 10% by weight of multifunctional compound such as epoxy compound, isocyanate compound and carboxylic dianhydride It is disclosed that the thermoplastic polyester resin composition is excellent in alkali resistance. However, in such a resin composition, cracks and cracks in the weld portion in an alkaline environment are improved to some extent, but there is a possibility that moldability and appearance characteristics associated with the seepage of the silicone compound and the fluorine compound may deteriorate. is there.

On the other hand, Japanese Patent Laid-Open No. 7-157463 (Patent Document 3) discloses a polyester thermoplastic elastomer composition comprising 100 parts by weight of a polyester thermoplastic elastomer and about 1 to 25 parts by weight of an olefin polymer modified silicone elastomer. It is described that the fluidity and releasability at the time are good and that sliding is effective. However, in Patent Document 3, there is no recognition of the effect of alkali resistance, and since it is based on an elastomer, it is not suitable for structural component applications that require heat resistance and rigidity.
JP 2002-356611 A (Claim 1 and paragraph number [0008]) International Publication No. WO 00/078867 (Claim 1 and pages 2 to 16) Japanese Patent Laid-Open No. 7-157463 (Claim 1 and paragraph number [0013])

  Accordingly, an object of the present invention is to provide a polybutylene terephthalate resin composition excellent in alkali resistance while being based on a PBT resin, and a molded product thereof.

  Another object of the present invention is a polybutylene terephthalate-based resin composition that has high alkali resistance at high temperatures and can suppress cracking due to environmental stress even if it comes into contact with alkali for a long time or frequently. It is to provide a product and its molded product.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have combined a PBT-based resin, a polyolefin-modified polysiloxane, and a filler (or reinforcing material), while being based on the PBT-based resin. The inventors found that the alkalinity can be improved and completed the present invention.

  That is, the polybutylene terephthalate resin composition of the present invention comprises a polybutylene terephthalate resin (A) containing at least a polybutylene terephthalate copolymer, a polyolefin-modified polysiloxane (B), and a filler (or reinforcing material). (C). The polybutylene terephthalate resin (A) may be a polybutylene terephthalate copolymer or a mixture of a polybutylene terephthalate copolymer and polybutylene terephthalate. The polybutylene terephthalate copolymer is usually composed of a butylene terephthalate unit and a copolymerizable monomer unit, and the proportion (modification amount) of the copolymerizable monomer unit in the polybutylene terephthalate resin (A) is 3. About 30 mol% may be sufficient. The polyolefin-modified polysiloxane (B) may be composed of a polyorganosiloxane and an olefin resin grafted on the polyorganosiloxane. The resin composition contains 1 to 30 parts by weight of a polyolefin-modified polysiloxane (B) and 5 to 80 parts by weight of a filler (C) with respect to 100 parts by weight of a polybutylene terephthalate resin (A). Also good. The resin composition may further contain an elastomer (D). The elastomer (D) may be at least one selected from a styrene elastomer and an olefin elastomer.

  The molded product formed with the said resin composition is also contained in this invention. This molded article may have a weld part at least partially, and may have at least one selected from an insert part, a press-fit part, and a screw part. Such a molded article is particularly excellent in alkali resistance and is suitable for use in an alkaline environment.

  In this specification, “alkaline resistance” means that the strength does not decrease or hardly occurs due to contact with an alkaline solution or immersion in an alkaline solution, or cracks or welds do not crack. Or it means that it is hard to occur, or its property or characteristic.

  In the present invention, since a PBT resin containing a PBT copolymer, a polyolefin-modified polysiloxane, and a filler or a reinforcing material are combined, the alkali resistance can be greatly improved despite being based on the PBT resin. . In addition, the resin composition or molded product of the present invention does not exude the silicone component even at high temperatures, and has high alkali resistance at high temperatures. Therefore, even if the resin composition or the molded product of the present invention is contacted with alkali for a long time or at a high frequency, it is possible to suppress the strength reduction and effectively prevent cracking due to environmental stress.

[Polybutylene terephthalate resin composition]
(A) Polybutylene terephthalate resin As the base resin, polybutylene terephthalate (PBT) resin includes PBT resin containing at least a polybutylene terephthalate copolymer (polybutylene terephthalate copolyester). The PBT resin may be any of a PBT copolymer and a mixture of polybutylene terephthalate (homopolyester) and the copolyester.

  The copolyester (butylene terephthalate copolymer or modified PBT resin) usually has a butylene terephthalate unit and a copolymerizable monomer (hereinafter sometimes simply referred to as a copolymerizable monomer) unit. Examples of the copolymerizable monomer corresponding to the copolymerizable monomer unit include dicarboxylic acid excluding terephthalic acid, diol excluding 1,4-butanediol, oxycarboxylic acid, and lactone. The copolymerizable monomers can be used alone or in combination of two or more.

Examples of the dicarboxylic acid include aliphatic dicarboxylic acids (for example, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, hexadecanedicarboxylic acid, dimer acid, etc. C _4-40 dicarboxylic acids, preferably C _4-20 dicarboxylic acids), alicyclic dicarboxylic acids (eg, C _8-12 dicarboxylic acids such as hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, highmic acid, etc.) Acid), aromatic dicarboxylic acids excluding terephthalic acid (for example, phthalic acid, isophthalic acid; naphthalenedicarboxylic acid such as 2,6-naphthalenedicarboxylic acid; 4,4′-diphenyldicarboxylic acid, 4,4′-diphenylether dicarboxylic acid) 4,4'-diphenyl ether dicarboxylic acid , 4,4'-diphenylmethane dicarboxylic acid, 4,4'-diphenyl ketone C _8-16 dicarboxylic acids), or reactive derivatives thereof, such as dicarboxylic acids (e.g., lower alkyl esters (dimethyl phthalate, dimethyl isophthalate ( Phthalic acid such as DMI) or C _1-4 alkyl esters of isophthalic acid), derivatives capable of forming esters such as acid chlorides and acid anhydrides), and the like. Furthermore, you may use together polyvalent carboxylic acids, such as trimellitic acid and a pyromellitic acid, as needed.

Examples of the diol include aliphatic diols excluding 1,4-butanediol [for example, alkanediol (for example, C such as ethylene glycol, trimethylene glycol, propylene glycol, neopentyl glycol, hexanediol, octanediol, and decanediol). _2-12 alkane diols, preferably C _2-10 alkane diols), polyalkylene glycols (glycols having a plurality of oxy C _2-4 alkylene units such as diethylene glycol, dipropylene glycol, ditetramethylene glycol, triethylene glycol, Tripropylene glycol, polytetramethylene glycol, etc.)], alicyclic diols (for example, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol) A etc.), aromatic diols [e.g., hydroquinone, resorcinol, C _6-14 aromatic diols such as naphthalene diol; biphenol; bisphenols; xylylene glycol], and others. Furthermore, you may use together polyols, such as glycerol, a trimethylol propane, a trimethylol ethane, a pentaerythritol, as needed.

Examples of the bisphenols include bis (4-hydroxyphenyl) methane (bisphenol F), 1,1-bis (4-hydroxyphenyl) ethane (bisphenol AD), 1,1-bis (4-hydroxyphenyl) propane, , 2-bis (4-hydroxyphenyl) propane (bisphenol A), 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2- Bis (hydroxyaryl) C ₁ such as bis (4-hydroxyphenyl) -3-methylbutane, 2,2-bis (4-hydroxyphenyl) hexane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane _-6 alkanes; 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydro Bis (hydroxyaryl) C _4-10 cycloalkanes such as xylphenyl) cyclohexane; 4,4′-dihydroxydiphenyl ether; 4,4′-dihydroxydiphenyl sulfone; 4,4′-dihydroxydiphenyl sulfide; 4,4′-dihydroxydiphenyl Examples thereof include ketones and their alkylene oxide adducts. Examples of the alkylene oxide adduct include C _2-3 alkylene oxide adducts of bisphenols (eg, bisphenol A, bisphenol AD, bisphenol F, etc.), such as 2,2-bis- [4- (2-hydroxyethoxy) phenyl. Propane, diethoxylated bisphenol A (EBPA), 2,2-bis- [4- (2-hydroxypropoxy) phenyl] propane, dipropoxylated bisphenol A, and the like. In the alkylene oxide adduct, the number of added moles of alkylene oxide (C _2-3 alkylene oxide such as ethylene oxide and propylene oxide) is about 1 to 10 moles, preferably about 1 to 5 moles with respect to each hydroxyl group. .

Examples of the oxycarboxylic acid include oxybenzoic acid, oxynaphthoic acid, hydroxyphenylacetic acid, glycolic acid, oxycaproic acid and other oxycarboxylic acids or derivatives thereof. Lactones include C _3-12 lactones such as propiolactone, butyrolactone, valerolactone, caprolactone (eg, ε-caprolactone).

Preferred copolymerizable monomers include diols [C _2-6 alkylene glycol (such as linear or branched alkylene glycol such as ethylene glycol, trimethylene glycol, propylene glycol, hexanediol, etc.), and a repeating number of 2 to 4]. Poly C _2-4 alkylene glycol having a certain oxyalkylene unit (such as diethylene glycol), 1,4-cyclohexanedimethanol, bisphenol (such as bisphenols or alkylene oxide adducts thereof), dicarboxylic acids [C _6-12 Aliphatic dicarboxylic acids (adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, etc.), asymmetric aromatic dicarboxylic acids in which the carboxyl group is substituted at the asymmetric position of the arene ring, and the like. Among these compounds, aromatic compounds such as alkylene oxide adducts of bisphenols (particularly bisphenol A), and asymmetric aromatic dicarboxylic acids [phthalic acid, isophthalic acid, and reactive derivatives thereof (dimethylisophthalic acid (DMI)) Etc., etc.] are preferred.

  The ratio of the copolymerizable monomer unit (copolymerizable monomer) in the PBT resin, that is, the amount of modification is, for example, 3 to 30 mol%, preferably 4 to 25 mol%, more preferably 5 to 20 mol% ( For example, it is about 5 to 15 mol%). The proportion of the copolymerizable monomer in the PBT resin may be about 5 to 30 mol%, preferably about 8 to 25 mol%, and more preferably about 10 to 20 mol%. A PBT resin containing a copolymerizable monomer unit at such a ratio is particularly suitable for improving alkali resistance. The amount of modification may be adjusted by adjusting the proportion of copolymerizable monomer units in the PBT copolymer, and the proportion of PBT copolymer and PBT may be adjusted. The amount of modification in the PBT resin may be adjusted by adjusting. Moreover, while adjusting the ratio of the copolymerizable monomer unit in a copolymer, you may adjust the ratio of a copolymer and PBT.

  The ratio of the PBT copolymer and PBT is not particularly limited, and can be appropriately selected from a ratio range in which the modification amount of the PBT resin is in the above range. The ratio (weight ratio) between the PBT copolymer and PBT is, for example, the former / the latter = 20/80 to 100/0 (for example, 25/75 to 99/1), preferably 30/70 to 95/5. (For example, 35/65 to 90/10), more preferably about 40/60 to 80/20.

  A PBT resin (polymer) is prepared by co-polymerizing terephthalic acid or a reactive derivative thereof and 1,4-butanediol with a monomer that can be optionally copolymerized by a conventional method such as transesterification or direct esterification. It can be produced by polymerization.

(B) Polyolefin-modified polysiloxane The polyolefin-modified polysiloxane (B) includes a copolymer having a polyolefin unit (including a polyalkadiene unit) and a polysiloxane unit in the molecule. When such a polyolefin-modified polysiloxane (B) is used, the alkali resistance of the PBT resin can be improved.

In such a polyolefin-modified polysiloxane, the polyolefin constituting the polyolefin unit may be an α-olefin (α-C ₂ -2) such as ethylene, propylene, 1-butene, 4-methylpentene, 1-hexene, 1-octene. ₁₂ olefin etc.) or a copolymer [for example, polyethylene (low density, medium density or high density polyethylene, etc.), polypropylene, ethylene-propylene copolymer, etc.], α-olefin and copolymerizable monomer [ For example, vinyl halide compounds such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate (fatty acid vinyl esters, etc.); (meth) acrylic acid, (meth) acrylic acid esters (alkyl such as ethyl (meth) acrylate) Esters (such as C _1-10 alkyl esters); Copolymer) with ethylene (eg, hydroxyalkyl esters such as hydroxyethyl acrylate (hydroxy C _1-10 alkyl esters); glycidyl (meth) acrylate), acrylic monomers such as (meth) acrylonitrile, etc.] -Vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, etc.), halogen-containing olefin resin (chlorinated polyethylene, etc.), etc., as well as alkadienes [butadiene, 1,5-hexadiene, C _4-20 alkadiene such as 1,6-heptadiene (such as C _4-16 alkadiene having double bonds at both ends)] or a copolymer thereof, the alkadiene and the exemplified copolymerizable monomer, and And / or a copolymer with the α-olefin. The polyolefin-modified polysiloxane may contain units corresponding to these polyolefins alone or in combination of two or more.

The polysiloxane constituting the polysiloxane unit includes organosiloxane having a saturated hydrocarbon group [for example, dialkylsiloxane (for example, dimethylsiloxane), alkylarylsiloxane (for example, phenylmethylsiloxane), diarylsiloxane ( For example, a chain siloxane such as diphenylsiloxane); a cyclic siloxane such as octamethylcyclotetrasiloxane (such as a cyclic polyalkylsiloxane)] or a copolymer, a polymerizable unsaturated group (for example, a vinyl group, an allyl group). , (Meth) acryloyl groups, etc.) [for example, alkylsiloxanes having polymerizable unsaturated groups such as vinylmethylsiloxane (C _1-4 alkylsiloxanes such as methylsiloxane); A homopolymer or copolymer of an arylsiloxane having a polymerizable unsaturated group such as ruphenylsiloxane (C _{6-10 arylsiloxane} such as phenylsiloxane)], an organosiloxane having a polymerizable unsaturated group and the saturated A copolymer with an organosiloxane having a hydrocarbon group (for example, vinylmethylsiloxane-dimethylsiloxane copolymer, vinylmethylsiloxane-phenylmethylsiloxane-dimethylsiloxane copolymer, etc.), an organo having the polymerizable unsaturated group Examples thereof include a copolymer of siloxane and / or an organosiloxane having a saturated hydrocarbon group and an alkoxysilane having a polymerizable unsaturated group (such as γ- (meth) acryloyloxypropyldimethoxymethylsilane). Polysiloxanes are ether-modified polysiloxanes introduced with polyoxy C _2-4 alkylene such as polyoxyethylene units, acid-modified polysiloxanes introduced with carboxyl groups and acid anhydride groups, and epoxies introduced with epoxy groups. It may be a modified polysiloxane, an amino-modified polysiloxane having an amino group introduced therein, or the like. The polyolefin-modified polysiloxane may contain units corresponding to these polysiloxanes alone or in combination of two or more.

  The polyolefin-modified polysiloxane is prepared by a conventional method, for example, (i) a hydrosilylation reaction between the α-olefin or alkadiene (or the polyolefin) and a polysiloxane having a Si—H bond (such as the polysiloxane), (ii) By a method of grafting by heating and kneading the polyolefin and organopolysiloxane (organosiloxane having the saturated hydrocarbon group exemplified above, organosiloxane having a polymerizable unsaturated group, etc.) and / or the polyorganosiloxane. Can be manufactured. In the grafting, if necessary, a polymerization initiator (such as an organic oxide) may be used. The details of the method for producing the polyolefin-modified polysiloxane include, for example, JP-A-1-217040, JP-A-1-278533, JP-A-1-318005, JP-A-2-55752, Reference can be made to JP-A-2-64115, JP-A-2-150441, JP-A-3-21611, JP-A-3-21612, JP-A-5-39411 and JP-A-7-157463. Further, the modified polyorganosiloxanes described in these publications may be used as the polyolefin-modified polyorganosiloxane (B).

The polyolefin-modified polysiloxanes can be used alone or in combination of two or more. Among the polyolefin-modified polysiloxanes, for example, polyorganosiloxane (the polyorganosiloxane) and an olefin resin grafted on the polyorganosiloxane (the polyolefin, in particular, α such as linear low density polyethylene (LLDPE)). -C _2-4 olefin homopolymer, ethylene-ethyl acrylate copolymer (EEA), ethylene-vinyl acetate copolymer (EVA), etc. α-C _2-4 olefin and vinyl ester and / or (meta A modified polysiloxane composed of, for example, a copolymer with an acrylate ester) is preferred.

  In addition, the ratio of the polyorganosiloxane unit with respect to the whole polyolefin-modified polysiloxane can be selected from a range of about 20 to 95% by weight, for example, and is usually 30% by weight or more (for example, about 30 to 90% by weight), Preferably it is 40 to 85 weight%, More preferably, it is about 50 to 80 weight%.

(C) Filler or reinforcing material Filler or reinforcing material (C) includes fibrous reinforcing material [for example, inorganic fiber (for example, glass fiber, silica fiber, alumina fiber, silica-alumina fiber, aluminum silicate fiber, zirconia Fiber, potassium titanate fiber, whisker (whisker such as silicon carbide, alumina, boron nitride), organic fiber (for example, acrylic resin such as aliphatic or aromatic polyamide, aromatic polyester, fluororesin, polyacrylonitrile, rayon) Etc.), plate-like reinforcing materials [eg talc, mica, glass flakes etc.], granular reinforcing materials [eg glass beads, glass powder, milled fibers (eg milled glass fibers etc.) etc. ], Wollastonite (wollastonite) and the like are included. The wollastonite may be in the form of a plate, a column, a fiber or the like. The average diameter of the fibrous reinforcing material may be, for example, about 1 to 50 μm (preferably 3 to 30 μm), and the average length may be, for example, about 100 μm to 3 mm (preferably 500 μm to 1 mm). Further, the average particle diameter of the plate-like or granular reinforcing material may be, for example, about 0.1 to 100 μm, preferably about 0.1 to 50 μm. These reinforcing materials can be used alone or in combination of two or more.

  Of these fillers or reinforcing materials (C), for example, glass-based or glassy fillers or reinforcing materials (glass fibers, glass flakes, glass beads, etc.), especially glass fibers, for example, having high strength and rigidity Glass fibers (such as chopped strands) are preferred.

(D) Elastomer The resin composition of the present invention may further contain an elastomer (thermoplastic elastomer) (D). In the resin composition containing an elastomer, the heat shock property of the resin composition can be improved. The elastomer (D) is preferably at least one selected from styrene-based elastomers and olefin-based elastomers from the viewpoint of alkali resistance and / or heat shock resistance.

  The said elastomer can be used individually or in combination of 2 or more types. The elastomer is usually composed of a hard segment (or hard component) and a soft segment (or soft component).

Examples of the styrenic elastomer include a hard segment composed of an aromatic vinyl monomer such as styrene, α-methylstyrene, vinyltoluene, or a copolymer, and an α-olefin (ethylene, propylene, 1-butene, 1 -Α-C _2-12 olefins such as hexene and 1-octene), diene monomers (butadiene, isoprene, etc.) and the like, and at least one monomer selected from homopolymers or copolymers. Examples thereof include a block with a soft segment or a graft copolymer (or a hydrogenated product thereof).

  The styrene elastomer is an acid-modified elastomer modified with an acid or acid anhydride such as (meth) acrylic acid or maleic anhydride, a copolymerizable monomer having a glycidyl group or an epoxy group (such as glycidyl (meth) acrylate). Or an elastomer having a reactive functional group such as an epoxy-modified elastomer obtained by epoxidizing an unsaturated bond of the elastomer.

  Typical styrene elastomers include styrene-diene-styrene block copolymers [styrene-butadiene-styrene block copolymers (SBS), styrene-isoprene-styrene block copolymers (SIS), etc.], hydrogenated blocks Copolymer [Styrene-ethylene-butylene-styrene block copolymer (or hydrogenated (styrene-butadiene-styrene block copolymer)) (SEBS), styrene-ethylene-propylene-styrene block copolymer (or hydrogenated) (Styrene-isoprene-styrene block copolymer)) (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), random styrene-butadiene copolymer hydrogenated polymer, etc.], these Functional group (epoxy) in the copolymer Modified copolymer having a di group, carboxyl group, acid anhydride group, etc.) [epoxidized styrene-diene copolymer in which unsaturated bond of diene is epoxidized (epoxidized styrene-diene-styrene block copolymer) And the like, etc.].

  Examples of the olefin-based elastomer include a block or graft copolymer (or a hydrogenated product thereof) of a hard segment composed of crystalline polyolefin and a soft segment composed of at least a rubber component.

As the polyolefin constituting the hard segment, an α-olefin (an α-C _2-12 olefin such as ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, Α-C _2-6 olefin, etc.) or a copolymer [polyethylene (low density polyethylene, ultra low density polyethylene, ultra ultra low density polyethylene, low molecular weight polyethylene, etc.), polypropylene, poly 1-butene, ethylene- Propylene copolymer, etc.), a copolymer of the α-olefin and a copolymerizable monomer, etc.]. As copolymerizable monomers, styrene monomers (substituted styrene such as styrene, α-methylstyrene, vinyltoluene, etc.), vinyl ester monomers (vinyl acetate, vinyl propionate, vinyl caproate, capryl) Acid ester, vinyl laurate, vinyl stearate, vinyl trifluoroacetate and the like, which may have a halogen atom, etc.), (meth) acrylic monomers [for example, (meth) acrylic acid or its Metal salt; (meth) acrylate ester (methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, ( Alkyl esters such as (meth) acrylic acid 2-ethylhexyl (such as C _1-10 alkyl esters); Hydroxyalkyl esters such as hydroxyethyl silylate (such as hydroxy C _1-10 alkyl ester); (meth) acrylic acid glycidyl ester etc.); (meth) acrylonitrile etc.], unsaturated carboxylic acids other than (meth) acrylic acid [for example , Β-unsaturated dicarboxylic acids such as maleic acid, fumaric acid, maleic anhydride, itaconic acid, itaconic anhydride, bicyclo (2,2,1) -5-heptene-2,3-dicarboxylic acid, or anhydrides thereof Ester of unsaturated carboxylic acid (alkyl ester such as ethyl fumarate (C _1-10 alkyl ester etc.); hydroxyethyl ester such as hydroxyethyl itaconate (hydroxy C _1-10 alkyl ester etc.); Glycidyl esters such as glycidyl ester); Bonic acid salts (metal salts, etc.)] and the like. These copolymerizable monomers can be used alone or in combination of two or more.

Specific examples of the copolymer of the α-olefin and the copolymerizable monomer include, for example, an α-olefin- (meth) acrylic acid copolymer (an ethylene- (meth) acrylic acid copolymer or the like). -C _2-4 olefin- (meth) acrylic acid copolymer, etc.), α-olefin- (meth) acrylic acid alkyl ester copolymer (for example, ethylene- (meth) methyl acrylate copolymer, ethylene- ( Such as meth) isopropyl acrylate copolymer, ethylene- (meth) acrylate n-butyl copolymer, ethylene- (meth) acrylate isobutyl copolymer, ethylene- (meth) acrylate 2-ethylhexyl copolymer, etc. alpha-C _2-4 olefin - (meth) acrylic acid alkyl ester copolymers and the like), alpha-olefin - vinyl ester copolymer (ethylene - vinyl acetate copolymer Ethylene - alpha-C _2-4 olefin such as vinyl propionate copolymer - vinyl ester copolymer, etc.), alpha-olefin - acrylic monomer-.alpha., beta-unsaturated carboxylic acid copolymer (e.g., Α-C _2-4 olefins such as ethylene-ethyl acrylate-maleic anhydride copolymer- (meth) alkyl acrylate-α, β-unsaturated carboxylic acid copolymers), α-olefin- (meth) Glycidyl acrylate copolymers (α-C _2-4 olefins such as ethylene-glycidyl methacrylate copolymers-glycidyl (meth) acrylate copolymers; ethylene-ethyl acrylate-glycidyl methacrylate copolymers, etc. α-C _2-4 Olefin-alkyl (meth) acrylate-glycidyl (meth) acrylate copolymer; ethylene-vinyl acetate-glycidyl methacrylate copolymer Α-C _2-4 olefin-vinyl ester- (meth) acrylic acid glycidyl copolymer, etc.).

The above polyolefins can be used alone or in combination of two or more. Preferred polyolefins are α-C _2-6 olefin homo- or copolymers, α-C _2-6 olefins and acrylic monomers (such as (meth) acrylic acid, (meth) acrylic acid esters) and / or vinyl. Copolymers with ester monomers (fatty acid vinyl esters such as vinyl acetate).

  The soft segment may be composed of a rubber component alone, and is a copolymer of a rubber component and a copolymerizable monomer (such as the α-olefin and / or the exemplified copolymerizable monomer). Usually, it is amorphous. Examples of the rubber component include diene rubbers (butadiene rubber, isoprene rubber, chloroprene rubber, etc.), ethylene-propylene rubber, ethylene-propylene-diene copolymer rubber (EPDM), nitrile rubber, acrylic rubber, butyl rubber, and natural rubber. And amorphous 1,2-polybutadiene, amorphous 1,4-polyisoprene, and the like. These rubber components can be used alone or in combination of two or more. The rubber component may be an uncrosslinked rubber or a crosslinked rubber (such as a partially crosslinked rubber). Among the rubber components, olefinic rubber components (for example, ethylene-propylene rubber, EPDM, etc.), especially copolymers of olefinic copolymer and diene rubber (olefinic copolymer rubber, for example, EPDM) are included. preferable.

  The olefin elastomers include ethylene-unsaturated carboxylic acid alkyl ester copolymers [ethylene- (meth) acrylic acid copolymers, ethylene-acrylic acid-ethyl acrylate copolymers, ethylene-ethyl acrylate copolymers. Polymers, ethylene-vinyl acetate copolymers, ethylene-vinyl acetate-ethyl acrylate copolymers, etc.] and vinyl polymers [eg, polymethyl methacrylate, polyethyl acrylate, polybutyl acrylate, polyacrylic acid] 2-ethylhexyl, polystyrene, polyacrylonitrile, acrylonitrile-styrene copolymer, butyl acrylate-methyl methacrylate copolymer, butyl acrylate-styrene copolymer alone or as a copolymer] and a graft copolymer Is also included. The ethylene-unsaturated carboxylic acid alkyl ester copolymer and the vinyl polymer can be used in appropriate combination. The ratio (weight ratio) between the ethylene-unsaturated carboxylic acid alkyl ester copolymer and the vinyl polymer is the former / the latter = 5/95 to 95/5, preferably 10/90 to 90/10, Preferably, it can select from the range of about 15 / 85-85 / 15.

Preferred olefin elastomers include α-C _2-6 olefin homo- or copolymers, and α-C _2-6 olefin and acrylic monomers ((meth) acrylic acid, (meth) acrylic acid ester, etc.). And / or a hard segment composed of at least one selected from a copolymer with a vinyl ester monomer (such as a fatty acid vinyl ester such as vinyl acetate) and a soft segment composed of an olefin rubber component Elastomers containing ethylene-unsaturated carboxylic acid alkyl ester copolymers (for example, ethylene-ethyl acrylate copolymers) and copolymers obtained by grafting vinyl polymers (for example, butyl acrylate-methyl methacrylate copolymers), etc. Is mentioned.

  The block structure of the thermoplastic elastomer is not particularly limited, and may be a triblock structure, a multiblock structure, a star block structure, or the like.

  In the thermoplastic elastomer, the weight ratio of the hard segment (or hard component) and the soft segment (or soft component) is usually the former / the latter = 10/90 to 90/10, preferably 20/80 to 80/20, More preferably, it is about 30/70 to 70/30 (for example, 40/60 to 60/40).

  Various additives such as stabilizers (antioxidants, ultraviolet absorbers, heat stabilizers, etc.), nucleating agents (crystallization nucleating agents), flame retardants, lubricants, mold release agents, antistatic agents are included in the resin composition. Coloring agents such as coloring agents and dyes, and dispersants may be added. Moreover, in order to improve hydrolysis resistance, heat shock resistance, etc., you may add epoxy compounds, such as a bisphenol A type epoxy compound and a novolak type epoxy compound. If necessary, other resins (such as styrene resins, acrylic resins, thermoplastic resins such as polyethylene terephthalate resins, thermosetting resins, etc.) may be used in combination.

  As the crystallization nucleating agent, in addition to organic nucleating agents such as rosin, inorganic nucleating agents such as metal oxides (silica, alumina, zirconia, titanium oxide, iron oxide, zinc oxide, etc.), metal carbonates (calcium carbonate, Examples include magnesium carbonate, barium carbonate, etc.), silicates (calcium silicate, aluminum silicate, talc, etc.), metal carbides (silicon carbide, etc.), metal nitrides (silicon nitride, boron nitride, tantalum nitride, etc.), etc. . These crystallization nucleating agents can be used alone or in combination of two or more.

(Ratio of each component)
The proportion of the polyolefin-modified polysiloxane (B) is, for example, 1 to 30 parts by weight (for example, 3 to 30 parts by weight), preferably 3 to 25 parts by weight (for example, with respect to 100 parts by weight of the PBT resin (A)). 5 to 25 parts by weight), more preferably about 5 to 20 parts by weight (for example, 7 to 20 parts by weight).

  The ratio of the filler or the reinforcing material (C) can be selected from the range of about 5 to 100 parts by weight with respect to 100 parts by weight of the PBT resin, and usually 5 to 80 parts by weight (for example, 10 to 80 parts by weight). The amount is preferably about 20 to 70 parts by weight, more preferably about 30 to 65 parts by weight (for example, 40 to 60 parts by weight).

  The ratio of the elastomer (D) is, for example, 5 to 50 parts by weight, preferably 10 to 40 parts by weight, more preferably 15 to 35 parts by weight (for example, 15 to 35 parts by weight) with respect to 100 parts by weight of the PBT resin (A). 30 parts by weight).

  The PBT resin composition of the present invention may be a powder mixture or a molten mixture (such as pellets). Since the resin composition is excellent in alkali resistance, it is useful for producing a resin molded body (molded article) in an application in contact with alkali.

[Molded product (molded product)]
The molded product of the present invention is formed of the resin composition. Such a molded article is composed of a PBT resin (A), a polyolefin-modified polysiloxane (B), a filler or reinforcing material (C), and other components (elastomer (D), etc.) as necessary. A conventional method, for example, (1) mixing each component, kneading with a uniaxial or biaxial extruder and extruding to prepare pellets, (2) once the composition Prepare different pellets (masterbatch), mix (dilut) the pellets with a predetermined amount, and use them for molding to obtain a molded product with a predetermined composition. (3) Directly add one or more of each component to the molding machine It can be manufactured by a method of charging. In addition, you may prepare a pellet by mixing a brittle component (glass type reinforcing material), after melt-mixing the component except a brittle component (glass type reinforcing material etc.), for example.

  The molded body may be formed by melt-kneading the PBT resin composition and using a conventional method such as extrusion molding, injection molding, compression molding, blow molding, vacuum molding, rotational molding, gas injection molding, etc. Molded by injection molding. The conditions for injection molding can be appropriately selected. For example, a PBT resin composition is melt-kneaded at about 250 to 280 ° C., pellets are prepared as necessary, and the cylinder temperature is about 250 to 280 ° C. with an injection molding machine. It may be injection molded. The mold temperature may be 60 ° C. or less (for example, about 40 to 60 ° C.).

  Molded parts are welded parts (that is, welded parts formed at the interface between resin flows by joining a plurality of resin flows in the mold cavity as the molded product is molded), metal or non-metallic materials In the case of being integrally formed with a member (hard member, for example, a metal terminal, etc.) composed of the above, an insert part for inserting the member, a press-fitting part for press-fitting the member, and the member are screwed. There may be provided a screwing portion for the purpose. Since the molded article of the present invention is excellent in alkali resistance, cracks and cracks do not occur even in the above-described parts when immersed in an alkaline solution. The molded product may have at least one site as described above.

  The molded article of the present invention can be applied to various uses, for example, electric / electronic parts, office automation (OA) equipment parts, home appliance parts, mechanical mechanism parts, automobile mechanism parts, daily necessities. In particular, it can be suitably used for automobile electrical parts (various control units, ignition coil parts, etc.), motor parts, various sensor parts, connector parts, switch parts, relay parts, coil parts, transformer parts, lamp parts, and the like. In particular, since the molded article has high alkali resistance, it is used in an alkaline environment, for example, a part or article exposed to a cleaning agent (alkaline cleaning agent) in a kitchen, toilet, bathroom, etc., a snow melting agent, etc. It is useful for automobile parts and the like used in contact with other alkaline agents.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

  In Examples and Comparative Examples, the following PBT resin (A), polyolefin-modified polysiloxane (B), filler or reinforcing material (C), and elastomer (D) were used.

(A) PBT resin
(A-1) Polybutylene terephthalate (PBT resin, Wintech Polymer Co., Ltd., DX2000)
(A-2) Dimethylisophthalic acid (DMI) modified PBT resin In the reaction of terephthalic acid with 1,4-butanediol, instead of a part of terephthalic acid (12.5 mol%), DMI as a copolymerization component 12 Modified PBT was prepared using 0.5 mol%.

(B) Polyolefin (PO) modified polysiloxane
(B-1) EEA-modified polysiloxane (silicone content 50% by weight, MI = 0.25 g / 10 min according to JIS K6760, melting point (mp) 85 ° C.)
(C) Filler or reinforcement
(C-1) Glass fiber: Nitto Boseki Co., Ltd., average fiber diameter φ11 μm chopped strand. Aminosilane / polyfunctional epoxy-treated product.

(D) Elastomer
(D-1) Olefin-based thermoplastic elastomer (copolymer obtained by grafting ethylene-ethyl acrylate copolymer with butyl acrylate-methyl methacrylate copolymer)
(D-2) Styrenic thermoplastic elastomer [hydrogenated (styrene-isoprene-butadiene) copolymer (styrene content 30 wt%, specific gravity 0.92, 5 wt% solution viscosity in toluene solution 90 mPa · sec (30 ° C. ))].

Examples 1-4 and Comparative Examples 1-5
(1) Preparation of test piece Each component was kneaded at 260 ° C by a twin-screw extruder (manufactured by Nippon Steel Works, 30 mmφ) at the ratio shown in Table 1 to prepare pellets. The obtained pellets were injection molded by an injection molding machine (manufactured by Toshiba Corporation) at a cylinder temperature of 260 ° C. and a mold temperature of 80 ° C., and ASTM 4 tensile test specimens and weld test specimens (longitudinal) 80 mm × width 80 mm × thickness 1 mm).

(2) Performance evaluation
(i) Alkali resistance stress cracking test With 1% strain applied to the weld specimen, the specimen was immersed in a 10% strength by weight sodium hydroxide aqueous solution at 23 ° C, and after 100 hours, cracks were generated on the surface of the specimen. The weld was observed with a stereomicroscope for cracks.
○: No crack and weld crack ×: Crack and / or weld crack

(ii) Tensile strength (TS) retention rate due to alkali immersion When ASTM 4 test specimen is immersed in a 10 wt% sodium hydroxide aqueous solution at 60 ° C. for 100 hours and the tensile strength before immersion is 100 The tensile strength after immersion was evaluated as tensile strength retention (%).
The results are shown in Table 1.

Claims (11)

  A polybutylene terephthalate resin composition comprising a polybutylene terephthalate resin (A) containing at least a polybutylene terephthalate copolymer, a polyolefin-modified polysiloxane (B), and a filler (C).   The resin composition according to claim 1, wherein the polybutylene terephthalate resin (A) is a polybutylene terephthalate copolymer or a mixture of a polybutylene terephthalate copolymer and polybutylene terephthalate.   The polybutylene terephthalate copolymer is composed of butylene terephthalate units and copolymerizable monomer units, and the proportion of copolymerizable monomer units in the polybutylene terephthalate resin (A) is 3 to 30 mol%. The resin composition according to claim 1.   The resin composition according to claim 1, wherein the polyolefin-modified polysiloxane (B) comprises a polyorganosiloxane and an olefin resin grafted on the polyorganosiloxane.   The resin composition according to claim 1, comprising 1 to 30 parts by weight of a polyolefin-modified polysiloxane (B) and 5 to 80 parts by weight of a filler (C) with respect to 100 parts by weight of the polybutylene terephthalate resin (A). .   The resin composition according to claim 1, further comprising an elastomer (D).   The resin composition according to claim 6, wherein the elastomer (D) is at least one selected from a styrene elastomer and an olefin elastomer.   A molded article formed from the resin composition according to claim 1.   The molded article according to claim 8, wherein at least a part thereof has a weld portion.   The molded product according to claim 8, comprising at least one selected from an insert portion, a press-fit portion, and a screw portion.   The molded article according to claim 8, which is used in an alkaline environment.