JP2004315805A - Resin composition for laser welding and molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polybutylene terephthalate (PBT)-based resin composition for laser welding, having high laser welding properties, welding strength and resistance to heat shock. <P>SOLUTION: This PBT-based resin composition for laser welding comprises a PBT-based resin (A) in an amount of 100 pts.wt., an elastomer (B) in an amount of 1-50 pts.wt. a filler or a reinforcing agent (C) in an amount of 0-100 pts.wt., and at least one kind of resin (D) selected from a polycarbonate-based resin (d1), a styrene-based resin (d2) and a polyethylene terephthalate-based resin (d3) in an amount of 0-80 pts.wt. The PBT-based resin (A) may comprise PBT homopolyester or a modified PBT-based copolymer which is modified with a copolymerizable monomer (such as bis-phenols, an alkylene oxide adduct thereof and an asymmetric aromatic dicarboxylic acid) in an amount of ≤45 mol%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polybutylene terephthalate resin composition having high laser welding property and excellent heat shock property, and a molded article using the same.

  Polybutylene terephthalate (PBT) -based resins have been used in many applications because of their excellent properties such as heat resistance, chemical resistance, electrical properties, mechanical properties, and moldability. Specific applications include various automotive electrical components (various control units, various sensors, ignition coils, etc.), connectors, switch components, relay components, coil components, and the like. In order to manufacture these parts, a plurality of molded parts are joined using a joining method such as an adhesive, screwing, snap fitting, hot plate welding, or ultrasonic welding. However, several problems have been pointed out with respect to these joining methods. For example, when an adhesive is used, there is a problem in that a loss of process time until the adhesive is cured and an environmental load are caused. Further, screwing increases the labor and cost of fastening, and hot plate welding or ultrasonic welding may cause damage to the product due to heat or vibration. On the other hand, the joining method by laser welding does not damage the product due to heat and vibrations caused by welding, and the welding process is very simple. For this reason, recently, the laser welding method has been widely used, and has attracted attention as a welding method for various resin parts. Further, among the resin parts to be subjected to welding, there is a resin part obtained by insert-molding a metal. Therefore, development of a PBT-based resin that can be insert-molded and has high laser weldability is desired as an insert-molding resin. In addition, as the performance of the resin required for the insert molded product, it is required that the resin be resistant to a high / low temperature change (heat shock property) over a long period of time, that is, excellent in high / low temperature impact resistance.

  On the other hand, it has been pointed out that when a PBT-based resin is joined by laser welding, the laser beam has low transmission, so that carbonization or the like occurs, and welding cannot be performed substantially. Japanese Patent Application Laid-Open No. 2001-26656 (Patent Document 1) discloses that a molded article formed of a polyester-based copolymer having a specific range of melting point and another molded article are integrated by welding to produce a molded article. A method for doing so is disclosed. This document describes that homopolyalkylene arylate resins (polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate) have low laser welding strength.

  JP-A-10-245481 (Patent Document 2) discloses that a composition composed of a thermoplastic polycarbonate resin and a thermoplastic polyester resin such as polyethylene terephthalate is added to a methacrylic acid in the presence of a crosslinked acrylate-based elastic material. There is disclosed a thermoplastic resin composition in which a methacrylic ester-based resin (graft resin) obtained by graft-polymerizing a monomer having an ester as a main component is blended at a ratio of 1 to 10% by weight. This document describes an example in which a bisphenol A-type polycarbonate resin and a polyethylene terephthalate resin are used in a ratio of 1.5 / 1 to 4/1 (weight ratio) in the resin composition. Further, as a thermal welding method of the composition, a hot plate welding method, a vibration welding method or an ultrasonic welding method is described. However, when this composition is subjected to laser welding, the transmittance of laser light is remarkably reduced, and not only cannot be welded by laser light, but also the mechanical strength and heat resistance decrease. Further, the resin composition has a reduced heat shock property in insert molding.

JP-A-63-3055 (Patent Document 3) discloses a specific acrylic rubber as a resin usable for metal insert molding, and JP-A-6-304963 (Patent Document 4) discloses a specific acrylic rubber. An olefin-based graft copolymer is disclosed. However, these elastomer components significantly reduce the transmittance of laser light and cannot be used for laser welding.
JP 2001-26656 A (claims, paragraph [0003]) JP-A-10-245481 (Claims) JP-A-63-3055 JP-A-6-304963

  Accordingly, an object of the present invention is to provide a PBT-based resin composition for laser welding, which is based on a PBT-based resin and has excellent laser welding properties and heat shock resistance, and a molded article thereof.

  Another object of the present invention is to provide a PBT-based resin composition having high laser beam transmittance and high welding strength, and a PBT-based resin molded product.

  The present inventors have conducted intensive studies to achieve the above object, and as a result, when a PBT-based resin and an elastomer having a specific refractive index and a specific resin are combined as required, a high laser welding property and a high fusion strength are obtained. And found that the heat shock resistance can be drastically improved, and completed the present invention.

  That is, the polybutylene terephthalate resin composition for laser welding of the present invention is composed of a polybutylene terephthalate resin (PBT resin) (A) and an elastomer (B). The resin composition further comprises a filler or reinforcing agent (C) and / or a polycarbonate resin (d1), a styrene resin (d2), and at least one resin (D3) selected from a polyethylene terephthalate resin (d3). ) May be included. The proportion of the elastomer (B) may be about 1 to 50 parts by weight based on 100 parts by weight of the resin (A), and the proportion of the filler or reinforcing agent (C) may be 100 parts by weight of the resin (A). May be about 0 to 100 parts by weight. The ratio of the resin (D) may be about 0 to 80 parts by weight (for example, 10 to 60 parts by weight) based on 100 parts by weight of the resin (A).

  The polybutylene terephthalate resin (A) may be a homopolyester (polybutylene terephthalate resin) or a copolyester (polybutylene terephthalate copolymer), and the copolyester is about 45 mol% or less. The resin may be a resin modified with a copolymerizable monomer (for example, about 0.01 to 40 mol%), particularly 30 mol% or less (for example, about 0.01 to 30 mol%). Examples of the copolymerizable monomer include bisphenols or an alkylene oxide adduct thereof (such as an alkylene oxide adduct of bisphenol A), an asymmetric aromatic dicarboxylic acid (such as phthalic acid and isophthalic acid), and an ester-forming derivative thereof. And so on. The refractive index of the elastomer may be, for example, about 1.52 to 1.59. The elastomer can be composed of a polystyrene-based thermoplastic elastomer, a polyester-based thermoplastic elastomer, or the like. Further, the filler or reinforcing agent (C) can be composed of various fillers or reinforcing materials, for example, glass fiber, glass flake, glass beads, talc, mica, wollastonite, potassium titanate fiber and the like.

  The present invention also includes a composite molded article in which a molded article formed of the resin composition and a resin molded article of a mating material are joined by laser welding.

  In the present invention, since the PBT resin and the elastomer are combined, the laser welding property and the heat shock resistance can be improved while using the PBT resin as a base. Further, the light transmittance and welding strength of the PBT-based resin molded product can be increased. Therefore, it is possible to obtain a molded product having high laser weldability (such as an insert molded product) and a composite molded product joined with high welding strength.

[Polybutylene terephthalate resin composition]
(A) PBT resin As a PBT resin as a base resin, butylene terephthalate is a main component (for example, about 50 to 100% by weight, preferably about 60 to 100% by weight, and more preferably about 75 to 100% by weight). Examples include homopolyester (polybutylene terephthalate) or copolyester (butylene terephthalate-based copolymer or polybutylene terephthalate copolyester).

  Examples of the copolymerizable monomer (hereinafter, sometimes simply referred to as a copolymerizable monomer) in the copolyester (butylene terephthalate-based copolymer or modified PBT resin) include dicarboxylic acids other than terephthalic acid and 1,4-butane Examples thereof include diols other than diols, oxycarboxylic acids, and lactones. 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 4-14} dicarboxylic acids), alicyclic dicarboxylic acids (e.g., hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, _{C 8-12} dicarboxylic such himic acid Acids), aromatic dicarboxylic acids other than terephthalic acid (eg, phthalic acid, isophthalic acid; naphthalenedicarboxylic acids such as 2,6-naphthalenedicarboxylic acid; 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid) , 4,4'-diphenylme Njikarubon acid, 4,4' _{C 8-16} diphenyl dicarboxylic acid and diphenyl ketone dicarboxylic acid), or phthalic such reactive derivatives thereof (e.g., lower alkyl esters (dimethyl phthalate, dimethyl isophthalate (DMI) An acid or isophthalic acid _C1-4 alkyl ester), an acid chloride, a derivative capable of forming an ester such as an acid anhydride) and the like. Further, if necessary, a polycarboxylic acid such as trimellitic acid or pyromellitic acid may be used in combination.

Diols include, for example, aliphatic alkylene glycols other than 1,4-butanediol (for example, linear or branched such as ethylene glycol, trimethylene glycol, propylene glycol, neopentyl glycol, hexanediol, octanediol, decanediol, etc.). Linear C _2-12 aliphatic glycols, preferably linear or branched C _2-10 aliphatic glycols), (poly) oxyalkylene glycols [glycols having a plurality of oxy C _2-4 alkylene units, for example, Diethylene glycol, dipropylene glycol, ditetramethylene glycol, triethylene glycol, tripropylene glycol, polytetramethylene glycol, etc.], alicyclic diols (eg, 1,4-cyclohexanediol, 1,4-cyclo Cyclohexanedicarboxylic methanol, and hydrogenated bisphenol A), aromatic diol [for example, hydroquinone, resorcinol, C _6-14 aromatic diols such as naphthalene diol; biphenol; bisphenols; xylylene glycol], and others. Further, if necessary, a polyol such as glycerin, trimethylolpropane, trimethylolethane or pentaerythritol may be used in combination.

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, 2,2-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 alkane; 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-h Bis (hydroxyaryl) C _4-10 cycloalkane such as droxyphenyl) cyclohexane; 4,4′-dihydroxydiphenyl ether; 4,4′-dihydroxydiphenyl sulfone; 4,4′-dihydroxydiphenyl sulfide; 4,4′- Examples thereof include dihydroxydiphenyl ketone and their alkylene oxide adducts. The alkylene oxide adduct, bisphenol (e.g., bisphenol A, bisphenol AD, bisphenol F, etc.) _{C 2-3} alkylene oxide adducts of, for example, 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 addition mole number of the alkylene oxide ( _C2-3 alkylene oxide such as ethylene oxide and propylene oxide) is 1 to 10 mol, preferably about 1 to 5 mol, for each hydroxyl group.

Examples of the oxycarboxylic acid include oxycarboxylic acids such as oxybenzoic acid, oxynaphthoic acid, hydroxyphenylacetic acid, glycolic acid, and oxycaproic acid, and derivatives thereof. Lactones include _C3-12 lactones such as propiolactone, butyrolactone, valerolactone, and caprolactone (eg, ε-caprolactone).

Preferred copolymerizable monomers include diols [C _2-6 alkylene glycols (such as linear or branched alkylene glycols such as ethylene glycol, trimethylene glycol, propylene glycol, and hexane diol); Polyoxy _C2-4 alkylene glycol having a certain degree of oxyalkylene units (such as diethylene glycol), bisphenols (such as bisphenols or alkylene oxide adducts thereof), dicarboxylic acids [C _6-12 aliphatic dicarboxylic acid (adipic acid, Pimelic acid, suberic acid, azelaic acid, sebacic acid, etc.), an asymmetric aromatic dicarboxylic acid in which a carboxyl group is substituted at an asymmetric position of an arene ring, 1,4-cyclohexanedimethanol, etc.]. Among these compounds, aromatic compounds, for example, alkylene oxide adducts of bisphenols (particularly bisphenol A), and asymmetric aromatic dicarboxylic acids [phthalic acid, isophthalic acid, and reactive derivatives thereof (dimethylisophthalic acid (DMI)) And the like).

  As the polybutylene terephthalate-based resin, a homopolyester (polybutylene terephthalate) and / or a copolymer (polybutylene terephthalate copolyester) is preferable, and the proportion (modification amount) of the copolymerizable monomer is usually 45 mol% or less ( For example, it may be about 0 to 40 mol%), preferably 35 mol% or less (for example, about 0 to 35 mol%), or 30 mol% or less (about 0 to 30 mol%). When used alone, the proportion of the copolymerizable monomer in the copolymer can be selected, for example, from the range of about 0.01 to 30 mol%, and is usually 1 to 30 mol%, preferably 3 to 25 mol%. And more preferably about 5 to 20 mol% (for example, 5 to 15 mol%). When used in combination with a homopolyester, the proportion of the copolymerizable monomer in the copolymer can be selected, for example, from the range of about 0.1 to 45 mol%, and is usually 1 to 40 mol% (for example, 5 to 40 mol%). %), Preferably about 10 to 35 mol%.

  When a homopolyester (polybutylene terephthalate) and a copolymer are used in combination, the ratio of the homopolyester to the copolyester is such that the ratio of the copolymerizable monomer is 0.1 to The range is about 30 mol% (preferably 1 to 25 mol%, more preferably 5 to 25 mol%), and usually the former / latter = 99/1 to 1/99 (weight ratio), preferably 95 / It can be selected from the range of about 5 to 5/95 (weight ratio), more preferably about 90/10 to 10/90 (weight ratio).

  The PBT-based resin is obtained by copolymerizing terephthalic acid or a reactive derivative thereof, 1,4-butanediol, and a copolymerizable monomer as necessary with a conventional method such as transesterification or direct esterification. Can be manufactured.

(B) Elastomer Various thermoplastic elastomers can be used as the elastomer. The refractive index of the elastomer may be, for example, about 1.52 to 1.59, preferably about 1.53 to 1.58. If the refractive index of the elastomer is too small or too large, scattering of transmitted light becomes remarkable, resulting in a decrease in welding energy.

The elastomer is usually composed of a hard segment (or a hard component) and a soft segment (or a soft component). The elastomer (thermoplastic elastomer), for example, a hard segment composed of a polystyrene-based elastomer [styrene, alpha-methyl styrene, homo- or copolymer of an aromatic vinyl monomer such as vinyl toluene, alpha-C _{2 -12} Block copolymer with a soft segment composed of a homo- or copolymer of a monomer selected from olefins (ethylene, propylene, butene, etc.), dienes (butadiene, isoprene, etc.) or hydrogenated blocks thereof Copolymer), a polyester-based elastomer [polyalkylene arylate (poly _C2-4 alkylene allylate such as polyethylene terephthalate and polybutylene terephthalate), a copolymer component of 1 to 30 mol% (for example, about 3 to 25 mol%) ( Modified or copolymerized with isophthalic acid A hard segment composed of a modified poly C _2-4 alkylene arylate which, polycaprolactone, composed oxy C _2-6 aliphatic polyether having an alkylene unit (poly C _2-6 alkylene glycol) and an aliphatic polyester With a soft segment formed by a soft segment], a polyamide elastomer [a copolymer with a hard segment formed of a polyamide and a soft segment formed of an aliphatic polyether such as poly _C2-6 alkylene glycol], Polyurethane elastomers [Copolymers of hard segments composed of short-chain glycol polyurethane and soft segments composed of aliphatic polyether or aliphatic polyester, such as polyester urethane elastomers], polyolefin elastomers An elastomer of a hard segment composed of polystyrene or polypropylene and a soft segment composed of ethylene-propylene rubber or ethylene-propylene-diene rubber, a crystalline syndiotactic 1,2-polybutadiene as a hard segment, amorphous 1,2 -A syndiotactic 1,2-polybutadiene-based elastomer having polybutadiene as a soft segment, a trans 1,4- having a crystalline trans 1,4-polyisoprene as a hard segment and an amorphous 1,4-polyisoprene as a soft segment. Polyisoprene elastomer etc.]. 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. These thermoplastic elastomers can be used alone or in combination of two or more.

Preferred thermoplastic elastomers include polyester-based elastomers and polystyrene-based elastomers. Representative polyester-based elastomers include polyester-polyester type thermoplastic elastomers (for example, poly C _2-4 alkylene arylate (particularly, a homopolymer having a polybutylene terephthalate unit, or 5 to 20 mol of ethylene glycol, isophthalic acid, or the like). %), A hard segment composed of an aromatic crystalline polyester such as a copolymer copolymerized at a ratio of about 2%, C _2-6 alkylene glycol such as polyethylene adipate and polybutylene adipate, and C _6-12 alkylene dicarboxylic acid. A block copolymer with a soft segment composed of an aliphatic polyester such as a polyester with an acid), a polyester / polyether thermoplastic elastomer (for example, a hard segment composed of the aromatic crystalline polyester and Block copolymers of polyoxy C _2-4 soft segment composed of a polyether and alkylene glycols such as polytetramethylene ether glycol), and the like liquid thermoplastic elastomer. Typical polystyrene elastomers include styrene-diene-styrene block copolymers [styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), etc.], hydrogenated weight [Styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), hydrogenated polymer of random styrene-butadiene rubber (SBR), unsaturated diene Epoxidized styrene-diene copolymer in which the bond is epoxidized (epoxidized styrene-diene-styrene block copolymer, etc.). These elastomers may be optionally provided with a functional group such as a carboxyl group or an epoxy group. It may have a group.

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

  The amount of the elastomer used is 1 to 50 parts by weight (for example, 2 to 50 parts by weight), preferably 3 to 40 parts by weight (for example, 5 to 35 parts by weight) with respect to 100 parts by weight of the PBT resin (A). More preferably, it is about 5 to 30 parts by weight.

(C) Filler or reinforcing agent The resin composition may contain a filler or a reinforcing material (C). Such reinforcing materials (C) include fibrous reinforcing materials [for example, inorganic fibers (for example, glass fibers, asbestos fibers, carbon fibers, silica fibers, alumina fibers, silica / alumina fibers, aluminum silicate fibers, zirconia fibers, Potassium titanate fiber, silicon carbide fiber, whisker (whisker of silicon carbide, alumina, silicon nitride, etc.), organic fiber (eg, aliphatic or aromatic polyamide, aromatic polyester, fluororesin, acrylic resin such as polyacrylonitrile) , A fiber formed of rayon, etc.), a plate-like reinforcing material [eg, talc, mica, glass flake, graphite, etc.], a granular reinforcing material [eg, glass beads, glass powder, milled fiber (eg, milled glass)] Fiber, etc.), wollastonite ( Apatite) and the like, wollastonite, plate-like, columnar, may be in the form of such fibers. The average diameter of the fibrous reinforcing material is, for example, about 1 to 50 μm (preferably 3 to 30 μm), and the average length is, for example, about 100 μm to 3 mm (preferably 300 μm to 1 mm, more preferably 500 μm to 1 mm). Is also good. Further, the average particle size of the plate-like or powder-granular reinforcing material may be, for example, about 0.1 to 100 μm, preferably about 0.1 to 50 μm (for example, about 0.1 to 10 μm). These fillers or reinforcing materials can be used alone or in combination of two or more.

  Among these reinforcing materials, glass-based or vitreous fillers or reinforcing materials (glass fibers, glass flakes, glass beads, etc.), talc, mica, wollastonite, and potassium titanate fiber are preferable.

  The ratio of the filler or the reinforcing material (C) can be selected, for example, from a range of about 0 to 100 parts by weight (for example, 0 to 80 parts by weight) with respect to 100 parts by weight of the PBT-based resin (A). It may be about 100 to 100 parts by weight (for example, 10 to 80 parts by weight), preferably about 20 to 80 parts by weight, more preferably about 30 to 80 parts by weight (for example, 40 to 70 parts by weight).

(D) Resin (second resin)
In order to improve light transmittance, the PBT-based resin composition may further contain a thermoplastic resin (second resin). Examples of the second resin include a polycarbonate (PC) resin (d1), a styrene resin (d2), and a polyethylene terephthalate (PET) resin (d3). These second resins (D) can be used alone or in combination of two or more. In the resin composition, the morphology of the polybutylene terephthalate-based resin (A) and the resin (D) is not particularly limited, and a uniform resin-based or dispersion-based resin may be formed.

(D1) Polycarbonate (PC) Resin A polycarbonate resin is obtained by reacting a dihydroxy compound with a carbonate such as phosgene or diphenyl carbonate. The dihydroxy compound may be an alicyclic compound or the like, but is preferably an aromatic compound (particularly a bisphenol compound).

Examples of the bisphenol compound include bisphenols exemplified in the above-mentioned PBT-based resin [for example, bis (hydroxyaryl) C _1-6 alkane; bis (hydroxyaryl) C _{4-10cycloalkane} ; 4,4′-dihydroxydiphenyl ether; 4,4'-dihydroxydiphenyl sulfone; 4,4'-dihydroxydiphenyl sulfide; 4,4'-dihydroxydiphenyl ketone, etc.]. Preferred polycarbonate resins include bisphenol A type polycarbonate.

(D2) Styrene-based resin As the styrene-based resin, for example, a styrene-based monomer (for example, styrene, vinyltoluene, α-methylstyrene, etc.) alone or a copolymer; (For example, unsaturated nitriles such as (meth) acrylonitrile, (meth) acrylic acid esters, (meth) acrylic acid, α, β-monoolefinic unsaturated carboxylic acids such as maleic anhydride or acid anhydrides or esters thereof, Copolymers with maleimide-based monomers such as maleimide, N-alkylmaleimide and N-phenylmaleimide); styrene-based graft copolymers, styrene-based block copolymers, and the like. Examples of the polystyrene-based graft copolymer include, for example, at least a styrene-based monomer, for example, a styrene-based monomer alone, or a styrene-based monomer and a vinyl monomer (for example, (meth) acrylonitrile and A resin obtained by graft polymerization of at least one monomer selected from (meth) acrylic esters and, if necessary, a monomer having a carboxyl group or an acid anhydride group or a maleimide-based monomer) can be exemplified. Examples of the rubber component include polybutadiene, acrylic rubber, chlorinated polyethylene, ethylene-vinyl acetate copolymer, ethylene-propylene rubber, ethylene-propylene-diene rubber, and styrene-butadiene copolymer rubber. As the polystyrene-based graft copolymer, for example, a resin obtained by graft-polymerizing at least a styrene-based monomer (for example, styrene and acrylonitrile and / or methyl methacrylate) to a rubber component (for example, an ABS resin, an MBS resin, etc.) And the like. These styrene resins can be used alone or in combination of two or more.

  Preferred styrene resins include polystyrene (GPPS), styrene- (meth) acrylate copolymers such as styrene-methyl methacrylate copolymer, styrene- (meth) acrylic acid copolymer, and styrene-maleic anhydride. Copolymer, styrene-acrylonitrile copolymer (AS resin), graft copolymer obtained by graft-polymerizing at least a styrene-based monomer to a rubber component [for example, impact-resistant polystyrene (HIPS), ABS resin, MBS resin, etc.] And so on.

(D3) Polyethylene terephthalate (PET) -based resin The polyethylene terephthalate-based resin contains ethylene terephthalate as a main component (for example, about 50 to 100% by weight, preferably about 60 to 100% by weight, more preferably about 75 to 100% by weight). (Polyethylene terephthalate, polyethylene terephthalate copolyester) and the like.

  Examples of the copolymerizable monomer in the copolyester (ethylene terephthalate copolymer or modified PET resin) include dicarboxylic acids other than terephthalic acid, diols other than ethylene glycol, oxycarboxylic acids, and lactones. As these copolymerizable monomers, in addition to butanediol, the copolymerizable monomers exemplified in the section of the PBT resin can be used. The copolymerizable monomers can be used alone or in combination of two or more.

Preferable copolymerizable monomers include the monomers exemplified in the section of the PBT resin, for example, diols [C _3-6 alkylene glycol (linear or branched alkylene such as trimethylene glycol, propylene glycol and butanediol). Glycol, etc.), (poly) oxyalkylene glycol, bisphenols or alkylene oxide adducts thereof, dicarboxylic acids [C _6-12 aliphatic dicarboxylic acid, asymmetric aromatic dicarboxylic acid, 1,4-cyclohexanedimethanol, etc.] and the like. Can be

  In the copolymer, the proportion (modification amount) of the copolymerizable monomer is about 1 to 30 mol%, preferably about 3 to 25 mol%, and more preferably about 5 to 20 mol%.

  The PET resin is obtained by copolymerizing terephthalic acid, ethylene glycol and, if necessary, a copolymerizable monomer by a conventional method, for example, transesterification or direct esterification.

  The amount of the resin (D) can be selected, for example, from a range of about 0 to 80 parts by weight (for example, 0 to 50 parts by weight) with respect to 100 parts by weight of the PBT resin (A). It is about 80 parts by weight (for example, 5 to 60 parts by weight), preferably about 10 to 60 parts by weight (for example, 20 to 40 parts by weight), and more preferably about 10 to 50 parts by weight (for example, 10 to 30 parts by weight). You may. If the amount of the resin (D) is small, the impact resistance and the thermal cycling resistance of the elastomer do not improve so much. If the amount is too large, the mechanical strength tends to decrease.

  Various additives such as stabilizers (antioxidants, ultraviolet absorbers, heat stabilizers, etc.), flame retardants, lubricants, mold release agents, antistatic agents, coloring agents such as dyes and pigments, You may add a dispersing agent, a plasticizer, a nucleating agent, etc. If necessary, it may be used in combination with another resin (such as a thermoplastic resin or a thermosetting resin). When the nucleating agent and the elastomer (B) are combined, the variation in the heat welding strength can be improved, and the welding can be performed reliably and easily. Therefore, the resin composition of the present invention may be composed of a combination of a PBT-based resin, an elastomer, and a nucleating agent, or a combination of a PBT-based resin, an elastomer, a second resin, and a nucleating agent. As the nucleating agent, an organic nucleating agent may be used, but inorganic nucleating agents (for example, metal oxides such as silica, alumina, zirconia, and titanium oxide; metal carbonates such as calcium carbonate and barium carbonate; talc and the like) Plate-like inorganic substances or silicates; metal carbides such as silicon carbide; metal nitrides such as silicon nitride, boron nitride, and tantalum nitride). The average particle diameter of the inorganic nucleating agent may be, for example, about 0.01 to 10 μm, preferably about 0.01 to 5 μm (eg, about 0.01 to 2 μm), and more preferably about 0.01 to 1 μm. The ratio of the nucleating agent to 100 parts by weight of the PBT resin (A) is 0.001 to 5 parts by weight (for example, 0.01 to 5 parts by weight), preferably 0.01 to 3 parts by weight (for example, 0.01 to 0.01 parts by weight). To 2 parts by weight), more preferably about 0.01 to 1 part by weight (e.g., 0.01 to 0.5 part by weight). The ratio of the nucleating agent to 100 parts by weight of the elastomer (B) is 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight (for example, 0.05 to 2.5 parts by weight), and more preferably 0.1 to 2.5 parts by weight. It may be about 1 to 1 part by weight (for example, 0.1 to 0.5 part by weight).

  The PBT-based resin composition of the present invention may be a powder mixture or a melt mixture (such as pellets). The resin composition of the present invention has high moldability and can produce a molded article or molded article having high mechanical strength and heat resistance. In particular, the molded article formed of the resin composition of the present invention has high light transmittance (particularly, light transmittance to laser light) despite being formed of the PBT-based resin composition, and is suitable for laser welding. ing. For example, in a molded product having a thickness of 2 mm formed by injection molding, the light transmittance at a wavelength of 800 to 1000 nm is 20% or more (for example, about 20 to 70%), preferably 25% or more (for example, 25 to 60). %), More preferably 30% or more (for example, about 30 to 50%). In addition, the resin composition of the present invention has high weldability with laser light, and thus is useful for producing a molded article to be welded using laser light.

[Molded body]
The molded body is prepared by using a resin composition composed of a PBT-based resin (A), an elastomer (B) and, if necessary, a reinforcing material (C) and / or a resin (D) in a conventional manner, for example, (1) A method in which each component is mixed, kneaded and extruded with a single-screw or twin-screw extruder to prepare pellets, and then molded. (2) A pellet (master batch) having a different composition is once prepared, and the pellet is placed in a desired place. It can be produced by a method of mixing (diluting) quantitatively and subjecting it to molding to obtain a molded article of a predetermined composition, or (3) a method of directly charging one or more of each component to a molding machine. The pellets may be prepared by, for example, melting and mixing components other than a brittle component (such as a glass-based reinforcing material) and then mixing a brittle component (such as a glass-based reinforcing material).

  The molded body may be melt-kneaded with the PBT resin composition and molded by a conventional method such as extrusion molding, injection molding, compression molding, blow molding, vacuum molding, rotational molding, gas injection molding, etc. , Formed by injection molding. In particular, the resin composition of the present invention has high heat shock resistance and is therefore suitable for insert molding.

  Although the shape of the molded product is not particularly limited, since the molded product is used by being joined to a counterpart material (other resin molded product) by laser welding, the shape usually has at least a contact surface (such as a flat surface) (for example, a plate shape). It is. Further, since the molded article of the present invention has high transparency to laser light, the thickness (thickness in the direction in which laser light is transmitted) of the molded article at a portion where laser light is transmitted can be selected from a wide range. It may be about 1 to 5 mm, preferably about 0.1 to 3 mm (for example, 0.5 to 3 mm).

  The laser light source is not particularly limited, and examples thereof include a dye laser, a gas laser (such as an excimer laser, an argon laser, a krypton laser, and a helium-neon laser), a solid-state laser (such as a YAG laser), and a semiconductor laser. Generally, a pulse laser is used as the laser light.

  Since the molded product is excellent in laser welding property, it is usually preferable to weld with a resin molded product of a mating material by laser welding, but if necessary, another heat welding method, for example, a vibration welding method, It can be welded to another resin molded product by an ultrasonic welding method, a hot plate welding method, or the like.

  The present invention also discloses a laser-molded composite molded article. In this composite molded article, a molded article (first molded article) formed of the PBT-based resin composition and a resin molded article (second molded article, adherend) of a mating material are joined by laser welding. It is integrated. For example, the interface between the first molded article and the second molded article is formed by bringing the first molded article and the second molded article into contact with each other (particularly at least at the joint portion in plane contact) and irradiating the laser beam. The two types of molded articles can be joined and integrated into one molded article by at least partially melting and bringing the joining surfaces into close contact and cooling. In such a composite molded article, when the molded article of the present invention is used, a high bonding strength is obtained by fusion, and a high fusion strength equivalent to that of a non-fused member not fused by laser light irradiation is maintained. it can.

  The resin constituting the resin molded product of the counterpart material is not particularly limited, and various thermoplastic resins, for example, olefin resin, vinyl resin, styrene resin, acrylic resin, polyester resin, polyamide resin And polycarbonate-based resins. Among these resins, polyester resins (aromatic polyester resins) such as resins of the same type or the same type as the resins constituting the PBT resin composition (PBT resins, PET resins, etc.), polycarbonate resins, styrene Base resin, acrylic resin, etc.) or its composition. For example, each of the first molded body and the second molded body may be formed of the PBT-based resin composition of the present invention.

  The adherend may include an absorber or a colorant for laser light. The colorant can be selected according to the wavelength of the laser beam, and can be selected from inorganic pigments such as black pigments such as carbon black (eg, acetylene black, lamp black, thermal black, furnace black, channel black, Ketjen black), and iron oxide. Red pigments such as red, orange pigments such as molybdate orange, white pigments such as titanium oxide, etc.), and organic pigments (such as yellow pigments, orange pigments, red pigments, blue pigments, and green pigments). These absorbents can be used alone or in combination of two or more. Usually, black pigments or dyes, especially carbon black, can be used as the absorbent. The average particle size of the carbon black may be generally from 10 to 1000 nm, preferably from about 10 to 100 nm. The ratio of the colorant is about 0.1 to 10% by weight, preferably about 0.5 to 5% by weight (for example, 0.5 to 3% by weight) based on the whole adherend.

  Irradiation of laser light is usually performed from the first molded body toward the second molded body, and is caused to generate heat at the interface of the second molded body containing the absorbing agent or the coloring agent, so that the first molded body is heated. The compact and the second compact are fused. If necessary, a laser beam may be focused on the interface between the first molded product and the second molded product by using a lens system to fuse the contact interface.

  Preferred embodiments of the present invention are as follows.

  (1) 100 parts by weight of at least one kind of polybutylene terephthalate-based resin (A) selected from homopolyester (polybutylene terephthalate) and copolyester (modified polybutylene terephthalate or polybutylene terephthalate-based copolyester) having butylene terephthalate unit And at least one thermoplastic elastomer (B) selected from a polystyrene thermoplastic elastomer and a polyester thermoplastic elastomer (B) in an amount of 2 to 50 parts by weight, and a filler or reinforcing agent (C) in an amount of 0 to 100 parts by weight. At least one resin (D) selected from the group consisting of a polycarbonate resin (d1), a styrene resin (d2) and a polyethylene terephthalate resin (d3); Tallates resin composition.

  (2) The resin composition containing at least one of a filler or reinforcing agent (C) and a resin (D).

  (3) Polybutylene terephthalate in which the copolyester is copolymerized with 3 to 25 mol% of at least one copolymerizable monomer selected from phthalic acid, isophthalic acid, an alkylene oxide adduct of bisphenol A, and a reactive derivative thereof. The above resin composition which is a system copolyester.

  (4) With respect to 100 parts by weight of polybutylene terephthalate resin (A), 5 to 30 parts by weight of thermoplastic elastomer (B), 0 to 80 parts by weight of filler or reinforcing agent (C), 0 to 0 parts of resin (D) The above resin composition containing 50 parts by weight.

  (5) The above resin composition which can be insert-molded and can be welded to a resin molding as a mating material by laser light.

  (6) An injection molded article formed from the resin composition.

  (7) The above-mentioned molded product which is an insert molded product including a metal member.

  The composite molded product obtained by the present invention has a high welding strength and has little damage to the PBT resin due to laser beam irradiation, so that it can be used in various applications, for example, electric / electronic parts, office automation (OA) equipment parts. It can be applied to home electric appliance parts, mechanical mechanism parts, automobile mechanism parts, etc. In particular, it can be suitably used for automotive electrical components (various control units, ignition coil components, etc.), motor components, various sensor components, connector components, switch components, relay components, coil components, transformer components, lamp components, and the like.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Examples 1 to 12 and Comparative Examples 1 to 5
In Examples and Comparative Examples, the following PBT-based resin (A), elastomer (B), filler (C), resin (D) and additives were used.

PBT resin (A)
(A-1) PBT resin: polybutylene terephthalate (manufactured by Wintech Polymer Co., Ltd.)
(A-2) Modified PBT resin: dimethyl isophthalic acid (DMI) modified PBT resin In the reaction between terephthalic acid and 1,4-butanediol, copolymerization is performed in place of part (12.5 mol%) of terephthalic acid. Using 12.5 mol% of dimethyl isophthalic acid (DMI) as a component, modified polybutylene terephthalate was prepared.

(A-3) Modified PBT resin: dimethyl isophthalic acid (DMI) modified PBT resin In the reaction between terephthalic acid and 1,4-butanediol, a copolymer component is used instead of part (30 mol%) of terephthalic acid. Of dimethyl isophthalic acid (DMI) was used to prepare a modified polybutylene terephthalate.

Elastomer (B)
(B-1) Polyester-based thermoplastic elastomer [“Perprene P-90BD” manufactured by Toyobo Co., Ltd.]
(B-2) Polyester-based thermoplastic elastomer [“Perprene S2002” manufactured by Toyobo Co., Ltd.]
(B-3) ESBS: Epoxy group-containing polystyrene-based thermoplastic elastomer [“Epofriend AT504” manufactured by Daicel Chemical Industries, Ltd.]
(B-4) ESBS: Epoxy group-containing polystyrene-based thermoplastic elastomer [“Epofriend AT510” manufactured by Daicel Chemical Industries, Ltd.]
(B-5) Acrylic thermoplastic elastomer [“MODIPA A5300” manufactured by NOF Corporation]
(B-6) EMAGMMA: Ethyl methacrylate-glycidyl methacrylate copolymer [“Rotada A8930” manufactured by Atofina Japan Co., Ltd.]
(B-7) EEA: ethylene-ethyl acrylate copolymer [NUC-6570 manufactured by Nippon Unicar Co., Ltd.]
Inorganic filler (C)
(C-1) Glass fiber (“Nitto Boseki Co., Ltd.“ CS3J-948S ”average fiber diameter φ11 μm, average fiber length 400 μm)
(C-2) Glass flakes (“REFG-101” manufactured by Nippon Glass Fiber Co., Ltd.)
(C-3) Mica (“21PU” manufactured by Mika Yamaguchi Co., Ltd.)
Thermoplastic resin (D)
(D-1) PC: polycarbonate resin (manufactured by Teijin Chemicals Limited, "Panlite L-1225")
(D-2) AS: Acrolinitrile-styrene resin ("Sebian NAP-20", manufactured by Daicel Chemical Industries, Ltd.)
(D-3) PET: polyethylene terephthalate-based resin [“EFG-10” manufactured by Kanebo Co., Ltd.]
Additive (E)
Boron nitride (manufactured by Mizushima Alloy Irons Co., Ltd., "Boron nitride FS-1", average particle size 0.1 to 0.5 [mu] m)
Pellets were produced by kneading at a rate shown in Tables 1 and 2 at 250 ° C. using a twin-screw extruder (30 mmφ, manufactured by Nippon Steel Works, Ltd.). A test piece A (8 cm long × 1 cm wide × 2 mm thick) was formed from the obtained pellets by an injection molding machine (manufactured by Toshiba Corporation) under the conditions of a cylinder temperature of 260 ° C. and a mold temperature of 80 ° C.

  In addition, as a test piece B to be welded to the test piece A, a test piece was used except that 100 parts by weight of the pellet and 3 parts by weight of carbon black for black coloring (trade name “2020C”, manufactured by Wintech Polymer Co., Ltd.) were used. A colored test piece B was produced in the same manner as in A. In addition, the test piece B functions as a heating element by the laser beam.

  As shown in FIG. 1, a part of the test piece A (3) is brought into contact with the test piece B (4) by overlapping, and a light source or a laser oscillator (1) is used using a laser welding machine (manufactured by Leister). The focus of the laser beam (2) was adjusted, and focused on the contact surface between the test piece A and the test piece B with a line width w (2 mm). Then, welding was performed by irradiating a laser beam (2) having a wavelength of 940 nm from the test piece A (3) side under the conditions of an output of 0 to 60 W and a scanning speed of 3 to 15 mm / sec.

(1) Measurement of welding strength A laser-welded test piece A and a test piece B were tensile-sheared at 10 mm / min using a tensile tester (manufactured by Orientec, RTC-1325), and the welding strength was measured.

(2) Light transmittance The light transmittance of the test piece A at a wavelength of 940 nm was measured using a spectrophotometer (V570, manufactured by JASCO Corporation).

(3) Refractive Index of Elastomer The refractive index of the elastomer (B) was measured for a test piece C (40 mm long × 10 mm wide × 1 mm thick) or a film.

(4) High / low temperature impact characteristics (cooling / heating cycle properties)
Using pellets, a resin temperature of 270 ° C., a mold temperature of 65 ° C., an injection time of 25 seconds, and a cooling time of 10 seconds were used to form a test piece molding die (in a prism of 22 mm long × 22 mm wide × 51 mm high, 18 mm long × Insert molding was performed on a metal mold (inserting an iron core having a width of 18 mm and a height of 30 mm) so that the minimum thickness of some of the resin moldings was 1 mm to produce insert molded products. The obtained insert molded product was heated at 140 ° C. for 1 hour and 30 minutes using a thermal shock tester, cooled to −40 ° C., cooled for 1 hour and 30 minutes, and further heated to 140 ° C. A high and low temperature impact test was performed as a cycle, and the number of cycles until a crack was formed in the molded product was measured to evaluate the high and low temperature impact resistance.

  Tables 1 and 2 show the results of Examples and Comparative Examples.

The resin compositions of the examples are excellent in not only the transmittance to laser light and the welding strength, but also the thermal cycle characteristics (heat shock resistance).

FIG. 1 is a schematic diagram for explaining laser welding in the embodiment.

Explanation of reference numerals

1. Light source 2. Laser light 3. Test piece A
4: Test piece B

Claims (11)

A polybutylene terephthalate resin composition for laser welding, comprising a polybutylene terephthalate resin (A) and an elastomer (B). The resin composition according to claim 1, further comprising a filler or a reinforcing agent (C). The resin composition according to claim 1, comprising 1 to 50 parts by weight of the elastomer (B) and 0 to 100 parts by weight of the filler or reinforcing agent (C) based on 100 parts by weight of the resin (A). The resin composition according to claim 1, further comprising at least one resin (D) selected from a polycarbonate resin (d1), a styrene resin (d2), and a polyethylene terephthalate resin (d3). The resin composition according to claim 4, comprising 0 to 80 parts by weight of the resin (D) based on 100 parts by weight of the resin (A). The resin composition according to claim 1, wherein the polybutylene terephthalate resin (A) is a homopolyester or a copolyester modified with 45 mol% or less of a copolymerizable monomer. The resin composition according to claim 6, wherein the copolymerizable monomer is at least one selected from bisphenols or an alkylene oxide adduct thereof, an asymmetric aromatic dicarboxylic acid, and an ester-forming derivative thereof. The resin composition according to claim 1, wherein the elastomer has a refractive index of 1.52 to 1.59. The resin composition according to claim 1, wherein the elastomer is at least one selected from a polystyrene-based thermoplastic elastomer and a polyester-based thermoplastic elastomer. The resin composition according to claim 2, wherein the filler or reinforcing agent (C) is at least one selected from glass fiber, glass flake, glass beads, talc, mica, wollastonite, and potassium titanate fiber. A composite molded article in which a molded article formed of the resin composition according to claim 1 and a resin molded article of a mating material are joined by laser welding.