JP2019094442A - Polybutylene terephthalate resin composition for molded body welding polyester elastomer, and composite molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polybutylene terephthalate resin composition for a molded body for adhering a polyester elastomer, which can be bonded by insert molding and has practical bonding strength even at a stress generation site. SOLUTION: Polybutylene terephthalate resin (A) 10 to 95% by mass, polyester elastomer (B) 4 to 42% by mass, semicrystalline copolymerized polyester resin (C) 1 to 50% by mass, and an inorganic filler (D). It is a polybutylene terephthalate resin composition containing 0 to 60% by mass, and is a polybutylene terephthalate resin composition for a molded body to which a polyester elastomer is welded. [Selection diagram] None

Description

  The present invention relates to a polybutylene terephthalate resin composition having improved adhesion to polyester elastomers.

Polybutylene terephthalate resin is used in a wide range of applications such as automobiles, electric and electronic parts as an engineering plastic because it has excellent mechanical properties, electrical properties, other physical and chemical properties, and good processability. ing.
However, although the molding efficiency of the injection molded article is good, the shape is limited in terms of the flow characteristics and the mold structure, and for example, it is difficult to mold a hollow molded article or the like. For this reason, conventionally, in joining of complicated parts having a product shape, joining using an adhesive, mechanical joining using a bolt or the like has been performed. However, in the case of an adhesive, its adhesive strength is a problem, and in the case of mechanical bonding by bolts or the like, cost, labor, and weight increase are problems.

  In joining methods such as hot plate welding, vibration welding, laser welding and ultrasonic welding, bonding can be performed in a short time, and since it is not necessary to use an adhesive or metal parts, the cost and weight increase thereof. Since problems such as environmental pollution can be reduced, bonding of parts by these methods is increasing (Patent Documents 1, 2, 3, 4).

  Patent Document 1 shows that by adding an elastomer and a glass fiber to a polybutylene terephthalate resin, vibrational weldability is improved without a large decrease in mechanical physical properties. However, these methods not only require the use of special machines for vibration welding, but also burrs generated during vibration welding may cause a post-processing step of the burrs. Patent Document 2 shows that the addition of an elastomer and glass fiber to a polybutylene terephthalate resin is excellent in durability and hydrolysis resistance in a thermal cycle environment. However, the disclosed composition is a secondary material for insert molding, and although the hydrolysis resistance is improved, it is not sufficient as adhesion resistance, and is not sufficient as insert bondability. In patent document 3, it has been found out that the hydrolysis resistance is improved without a significant decrease in mechanical properties by the limitation of the terminal carboxyl group and the addition of carbodiimide. However, although this composition is excellent as a material for thermal welding, a special machine for thermal welding must be used at the time of joining as in Patent Document 1, and burrs are generated in the thermal weld as in vibration welding. And burr post-processing steps may occur. In Patent Document 4, there is a correlation between the molecular weight of the polybutylene terephthalate resin and the vibration welding strength, and the flowability of the resin composition constituting the molded article is enhanced while the vibration welding strength is enhanced by adjusting the molecular weight within a specific range. Shows that it does not impair. However, in this patent document as well as patent document 1, a special machine for vibration welding must be used at the time of joining, and burrs may occur at welds, which may cause a post-processing step of the burrs.

  By the way, if it can join by insert molding, a special welding installation is not required and it can shape | mold a composite molded object simply. Furthermore, in mechanical bonding such as vibration welding, there is also a problem that variation in molding conditions is large. Moreover, in patent documents 1-4, there is no technical thought which joins polyester elastomer by insert molding with respect to a polybutylene-terephthalate-resin type | mold molded article at all.

Unexamined-Japanese-Patent No. 2006-176691 WO 2009/150831 brochure WO 2010/122915 pamphlet International Publication No. 2013/047708 brochure

  The present invention is intended to solve the above-mentioned problems, and can be joined (welded) by insert molding without requiring a special welding facility, and further, it is a joint strength having practicality even at a stress generation site. The present invention provides a polybutylene terephthalate resin composition having Among them, a composite molded article having both excellent properties of both polybutylene terephthalate resin and polyester elastomer is requested from the market by joining (welding) polyester elastomer by insert molding to a polybutylene terephthalate resin molded article, There is a need for a resin composition for a polybutylene terephthalate resin-based molded article necessary for this composite molded article. As a result of investigations by the present inventors, it is difficult to practically join (welding) practically any other resin as well as polyester elastomer by insert molding to a polybutylene terephthalate resin molded product, and it was possible to join Also, it has been found that the shape of the molded body is restricted and it can not be used for parts where the joint is stressed. Therefore, it is an object to provide a polybutylene terephthalate resin composition for molded articles having a bonding strength which can be joined by insert molding and which has practical joint strength even at a stress generation site. The The present inventors propose a polybutylene terephthalate resin composition containing a polybutylene terephthalate resin, a polyester elastomer, a copolymerized polyester resin, and an inorganic filler in a predetermined ratio as a resin composition for solving this problem, and has a bonding property. It has been found that an amorphous polyester resin is preferable as the copolyester resin in order to improve the cohesion. However, it was newly found that such a polybutylene terephthalate resin composition has a problem that the deflection temperature under load decreases. Therefore, an object of the present invention is to provide a polybutylene terephthalate resin composition for molded articles which can solve the above-mentioned problems and can suppress a decrease in deflection temperature under load.

  MEANS TO SOLVE THE PROBLEM The present inventors came to complete this invention, as a result of earnestly examining the structure and characteristic of a polybutylene-terephthalate-resin composition, in order to solve said subject.

That is, the present invention has the following constitution.
[1] 10 to 95% by mass of polybutylene terephthalate resin (A), 4 to 42% by mass of polyester elastomer (B), 1 to 50% by mass of semicrystalline copolyester resin (C) and inorganic filler (D) 0 It is a polybutylene-terephthalate-resin composition containing -60 mass%, Comprising: The polybutylene-terephthalate-resin composition which is for molded objects which weld a polyester elastomer.
[2] The semi-crystalline copolyester resin (C) is a polyester resin in which at least one of an alkyl side chain-containing glycol and isophthalic acid is copolymerized with an ethylene terephthalate unit or a butylene terephthalate unit according to [1] Polybutylene terephthalate resin composition.
[3] The polybutylene terephthalate resin according to [1], wherein the semicrystalline copolyester resin (C) is a polyester resin obtained by copolymerizing at least one of an alkyl side chain containing glycol and isophthalic acid with a butylene terephthalate unit. Composition.
[4] A composite molded article obtained by welding a molded article made of the polybutylene terephthalate resin composition according to any one of [1] to [3] and a polyester elastomer.
[5] Production of a composite molded article in which a molded article made of the polybutylene terephthalate resin composition according to any one of [1] to [3] is disposed as an insert material in a mold and the polyester elastomer is welded by injection molding Method.

  According to the present invention, the polybutylene terephthalate resin can be joined to the polyester elastomer by insert molding by adding the polyester elastomer. Furthermore, the decrease in deflection temperature under load, which is a contradiction to the improvement in adhesion by the amorphous copolyester resin, can be suppressed by the use of the semicrystalline copolyester resin. A composite molded article in which a molded article made of the polybutylene terephthalate resin composition of the present invention and a polyester elastomer are welded is an insert composite molded article which can be obtained by a simple method called insert molding without requiring special equipment. is there. Further, in the joint portion of the composite molded body, the molded body made of the polybutylene terephthalate resin composition and the polyester elastomer are directly joined (welded) without an adhesive or a bolt, and the joint portion is It has sufficient bonding strength which is practical.

The present invention will be specifically described below.
[Polybutylene terephthalate resin (A)]
Polybutylene terephthalate resin is generally produced by a polycondensation reaction of a dicarboxylic acid containing terephthalic acid or its ester-forming derivative as the main component and a diol containing 1,4-butanediol or its ester-forming derivative as the main component. Obtainable by conventional polymerization methods. The polybutylene terephthalate resin preferably has a repeating unit of butylene terephthalate of 80 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, and 100 mol%. Is particularly preferred.

  The polybutylene terephthalate resin can contain other polymerization components within a range that does not impair its properties, for example, about 20% by mass or less. Examples of polybutylene terephthalate resins containing other polymerization components include polybutylene (terephthalate / isophthalate), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene (terephthalate) / Naphthalate), poly (butylene / ethylene) terephthalate and the like. These components may be used alone or in combination of two or more.

  The intrinsic viscosity (IV) of the polybutylene terephthalate resin is not particularly limited, but is preferably 0.5 to 1.6 dl / g, and more preferably 0.7 to 1.3 dl / g. And is more preferably 0.8 to 1.1 dl / g. The polybutylene terephthalate resin composition produced according to the present invention has good mechanical properties and chemical properties because the intrinsic viscosity (IV) of the polybutylene terephthalate resin is 0.5 to 1.6 dl / g. .

  The amount of terminal carboxyl groups of the polybutylene terephthalate resin is not particularly limited because it does not affect the bonding property. However, since the terminal carboxyl group plays a catalytic role in the hydrolysis reaction of the polymer, the hydrolysis is accelerated as the amount of terminal carboxyl group increases. For this reason, it is preferable that the concentration of this terminal carboxyl group is low. The concentration (acid value) of the terminal carboxyl group of the polybutylene terephthalate resin is preferably 40 eq / ton or less, more preferably 30 eq / ton or less, and still more preferably 25 eq / ton or less.

  For the concentration of terminal carboxyl groups of polybutylene terephthalate resin (unit: eq / ton), for example, a predetermined amount of polybutylene terephthalate resin is dissolved in benzyl alcohol, and a 0.01 mol / 1 benzyl alcohol solution of sodium hydroxide is used It can be measured by titration. For example, a phenolphthalein solution may be used as the indicator.

  The content of the polybutylene terephthalate resin (A) in the polybutylene terephthalate resin composition is 10 to 95% by mass, preferably 25 to 95% by mass, and more preferably 50 to 80% by mass. By blending the polybutylene terephthalate resin (A) within this range, it is possible to obtain a polyester elastomer bondable polybutylene terephthalate resin composition having practical bonding strength.

[Polyester Elastomer (B)]
The polyester elastomer (B) used in the present invention includes a hard segment consisting of a polyester comprising an aromatic dicarboxylic acid and an aliphatic and / or alicyclic glycol as a component, an aliphatic polyether, an aliphatic polyester and a fat. It is preferable that it is a polyester elastomer to which at least one soft segment selected from group polycarbonates is bonded.

  In the polyester elastomer (B) used in the present invention, as the aromatic dicarboxylic acid constituting the hard segment polyester, a common aromatic dicarboxylic acid is widely used and is not particularly limited. Specific examples thereof include terephthalic acid and isophthalic acid. Acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,2-bis (phenoxy) ethane-p, p'-dicarboxylic acid, diphenyl-p, p-dicarboxylic acid, and these Functional derivatives of Preferred are terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid and diphenyl-p, p-dicarboxylic acid, and they tend to have high crystallization rates and good formability. Particularly preferred are terephthalic acid and terephthalic acid dimethyl ester, isophthalic acid and isophthalic acid dimethyl ester, 2,6-naphthalenedicarboxylic acid and 2,6-naphthalenedicarboxylic acid dimethyl ester. Furthermore, aliphatic dicarboxylic acids such as adipic acid, sebacic acid, succinic acid, glutaric acid and dimeric acid and functional derivatives thereof, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid and cyclohexanedicarboxylic acid, and The functional derivative can also be used at less than 50 mol%. If the component other than the aromatic dicarboxylic acid is preferably less than 50 mol%, more preferably less than 40 mol%, more preferably less than 30 mol%, and 50 mol% or more, the crystallinity of the polyester elastomer tends to decrease. Moldability and heat resistance tend to decrease.

  In the polyester elastomer (B) used in the present invention, as the aliphatic or alicyclic glycol constituting the polyester of the hard segment, general aliphatic or alicyclic glycols are widely used, and although not particularly limited, It is desirable that they are C2-C8 alkylene glycols. Preferred are ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol and 1,4-cyclohexanedimethanol, and particularly preferred are ethylene glycol and 1,4-butanediol. It is either.

  As components constituting the above hard segment polyester, those comprising an ethylene terephthalate unit (unit consisting of terephthalic acid and ethylene glycol) or a butylene terephthalate unit (unit consisting of terephthalic acid and 1,4-butanediol), Preferred from the point of formability and cost performance.

  When an aromatic polyester suitable as a polyester constituting the hard segment in the polyester elastomer (B) used in the present invention is prepared in advance and then copolymerized with a soft segment component, the aromatic polyester is a normal polyester It can be easily obtained according to the production method of Further, such polyester preferably has a number average molecular weight of 10,000 to 40,000.

The soft segment of the polyester elastomer (B) used in the present invention is at least one selected from aliphatic polyethers, aliphatic polyesters and aliphatic polycarbonates. Examples of aliphatic polyethers include polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, polyoxyhexamethylene glycol, polyoxytrimethylene glycol, copolymer of ethylene oxide and propylene oxide, ethylene oxide of polyoxyethylene glycol An adduct, a copolymer of ethylene oxide and tetrahydrofuran and the like can be mentioned.
Moreover, as aliphatic polyester, poly ((epsilon) -caprolactone), polyenant lactone, polycaprylo lactone, polybutylene adipate etc. are mentioned.

  Moreover, it is preferable that an aliphatic polycarbonate is what mainly consists of a C2-C12 aliphatic diol residue. Examples of these aliphatic diols include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, and 2, 2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,9-nonanediol, 2-methyl-1,8- An octanediol etc. are mentioned. In particular, aliphatic diols having 5 to 12 carbon atoms are preferable from the viewpoint of the flexibility and low temperature properties of the polyester elastomer (B) to be obtained. These components may be used alone or in combination of two or more as needed, based on the cases described below.

  In the present invention, as an aliphatic polycarbonate diol having good low temperature properties, which constitutes the soft segment of usable polyester elastomer, one having a low melting point (for example, 70 ° C. or less) and a low glass transition temperature is preferable. Generally, an aliphatic polycarbonate diol composed of 1,6-hexanediol used to form a soft segment of polyester elastomer has a low glass transition temperature of around -60 ° C and a melting point of around 50 ° C, so the low temperature characteristics Will be good. In addition, an aliphatic polycarbonate diol obtained by copolymerizing an appropriate amount of, for example, 3-methyl-1,5-pentanediol with the above aliphatic polycarbonate diol has a glass transition point relative to the original aliphatic polycarbonate diol Although it is slightly higher, the melting point is lowered or it becomes amorphous, so it corresponds to an aliphatic polycarbonate diol having good low temperature properties. Also, for example, an aliphatic polycarbonate diol consisting of 1,9-nonanediol and 2-methyl-1,8-octanediol has a melting point of about 30 ° C. and a glass transition temperature of about −70 ° C., which is low enough. Is a good aliphatic polycarbonate diol.

  The polyester elastomer (B) used in the present invention is a copolymer comprising terephthalic acid, 1,4-butanediol and polyoxytetramethylene glycol as main components, for reasons of economy, heat resistance and cold resistance. Is preferred. In the dicarboxylic acid component constituting the polyester elastomer (B), terephthalic acid is preferably 40 mol% or more, more preferably 70 mol% or more, and still more preferably 80 mol% or more, 90 mol % Or more is particularly preferred. It is preferable that the sum total of 1, 4- butanediol and polyoxy tetramethylene glycol is 40 mol% or more in the glycol component which comprises a polyester elastomer (B), It is more preferable that it is 70 mol% or more, 80 mol % Or more is more preferable, and 90 mol% or more is particularly preferable.

  It is preferable that the number average molecular weight of the said polyoxy tetramethylene glycol is 500-4000. When the number average molecular weight is less than 500, it may be difficult to develop elastomeric properties. On the other hand, when the number average molecular weight exceeds 4,000, the compatibility with the polyester portion constituting the hard segment of the polyester elastomer (B) may be reduced, which may make it difficult to copolymerize in block form. The number average molecular weight of the polyoxytetramethylene glycol is more preferably 800 or more and 3,000 or less, and still more preferably 1,000 or more and 2,500 or less.

  In the copolymerized amount of hard segment and soft segment of polyester elastomer (B) used in the present invention, the weight ratio of hard segment / soft segment is preferably 85/15 to 35/65, more preferably 75 / 25 to 50/50.

  The hardness (surface hardness) of the polyester elastomer (B) used in the present invention is not particularly limited. For example, polyester elastomers having a wide range from low hardness of about 25 Shore A hardness to high hardness of about 75 Shore D hardness are used Possible, preferably Shore D hardness 25-65, more preferably Shore D hardness 25-40.

  The reduced viscosity of the polyester elastomer (B) used in the present invention is preferably 0.5 dl / g or more and 3.5 dl / g or less as measured by the measurement method described later. If it is less than 0.5 dl / g, the durability as a resin is low, and if it exceeds 3.5 dl / g, processability such as injection molding may be insufficient. The reduced viscosity of the polyester elastomer (B) is more preferably 1.0 dl / g or more and 3.0 dl / g or less, and still more preferably 1.5 dl / g or more and 2.8 dl / g or less. Moreover, 200 eq / t or less is preferable and, as for an acid value, 50 eq / t or less is especially preferable.

  The polyester elastomer (B) used in the present invention can be produced by a known method. For example, a method of transesterifying a lower alcohol diester of dicarboxylic acid, an excess of low molecular weight glycol, and a soft segment component in the presence of a catalyst and polycondensing the resulting reaction product, or dicarboxylic acid and excess glycol and The soft segment component is subjected to an esterification reaction in the presence of a catalyst, and the resulting reaction product is polycondensed, or a hard segment is prepared beforehand, to which the soft segment component is added and randomized by a transesterification reaction Any method may be used such as a method, a method of linking a hard segment and a soft segment by a chain linking agent, and addition reaction of an ε-caprolactone monomer to the hard segment when poly (ε-caprolactone) is used for the soft segment.

  The content of the polyester elastomer (B) in the polybutylene terephthalate resin composition is 4 to 42% by mass, preferably 5 to 40% by mass, and more preferably 15 to 30% by mass. By blending the polyester elastomer (B) within this range, it becomes possible to obtain a polyester elastomer bondable polybutylene terephthalate resin composition having practical bonding strength.

[Semicrystalline Copolyester Resin (C)]
The semicrystalline copolyester resin (C) in the present invention is a resin different from the polybutylene terephthalate resin (A) and the polyester elastomer (B) described above.
The semicrystalline copolyester resin (C) in the present invention is a copolyester resin having a melting peak indicating a melting point when measured using a differential scanning calorimeter (DSC). The measuring method of melting | fusing point uses the method as described in the term of the following Example. Also, a semi-crystalline copolyester resin means a crystalline part and an amorphous part in the skeleton, ie, in an amorphous polymer matrix in which the amorphous polymer part is present as randomly entangled chains, It is a copolyester resin having a structure in which a crystalline polymer portion is present as regularly arranged domains. The heat of fusion of the semicrystalline copolyester resin is preferably more than 5 J / g.

  Specifically, the semi-crystalline copolyester resin (C) in the present invention is 75 mol% of ethylene glycol, assuming that 100 mol% of the total acid component constituting and 100 mol% of the total glycol component constituting A resin containing 50 to 180 mol% of terephthalic acid and ethylene glycol in total, or 50 mol% or more of 1,4-butanediol and 100 to 180 mol of terephthalic acid and 1,4-butanediol in total % Resin is preferred. As copolymerization components, isophthalic acid, sebacic acid, adipic acid, trimellitic acid, 2,6-naphthalenedicarboxylic acid, diethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,4-butanediol, 1 And at least one selected from the group consisting of 2-propanediol, 1,3-propanediol, ethylene glycol and 2-methyl-1,3-propanediol. Ethylene glycol and 1,4-butanediol can be copolymerization components in polyester resins not contained in the main components.

  The semicrystalline copolyester resin (C) is preferably a polyester resin obtained by copolymerizing at least one of an alkyl side chain-containing glycol and isophthalic acid with an ethylene terephthalate unit or a butylene terephthalate unit, and a butylene terephthalate unit. More preferably, it is a polyester resin obtained by copolymerizing at least one of an alkyl side chain-containing glycol and isophthalic acid. The alkyl side chain-containing glycols include neopentyl glycol, 1,2-propanediol, and 2-methyl-1,3-propanediol. Among them, neopentyl glycol and isophthalic acid are preferable from the viewpoint of various properties as a copolymerization component, and in particular isophthalic acid, which can be an amorphous part in the skeleton.

  The melting point of the semicrystalline copolyester resin (C) is not particularly limited, but in the case of a polyester resin obtained by copolymerizing at least one of an alkyl side chain-containing glycol and isophthalic acid in ethylene terephthalate units, 180 to 250 ° C. is preferable. 200-230 degreeC is more preferable. In the case of the polyester resin which copolymerized at least one of the alkyl side chain containing glycol and isophthalic acid to a butylene terephthalate unit, 120-210 degreeC is preferable and 130-200 degreeC is more preferable.

10-50 mol% is preferable and, as for the copolymerization ratio of alkyl side chain containing glycol, when the total glycol component which comprises semi-crystalline copolyester resin (C) is 100 mol%, 10-25 mol% is more preferable. .
When the total acid component which comprises semi-crystalline copolyester resin (C) is 100 mol%, 20-60 mol% is preferable and, as for the copolymerization ratio of isophthalic acid, 25-55 mol% is more preferable.

  The degree of polymerization of the semicrystalline copolyester resin (C) varies slightly depending on the specific copolymerization composition, but the intrinsic viscosity (0.1 g of the sample is a mixed solvent of phenol / tetrachloroethane (mass ratio 6/4) It is preferable that it is melt | dissolved in 25 ml, and it is 0.4-1.5 dl / g (measured at 30 degreeC using a Ubbelohde viscosity tube), and 0.4-1.3 dl / g is more preferable. If it is less than 0.4 dl / g, it is not preferable because the toughness decreases, and if it exceeds 1.5 dl / g, it is not preferable because the fluidity decreases.

  The content of the semicrystalline copolyester resin (C) is 1 to 50% by mass, preferably 1 to 30% by mass, and more preferably 1 to 25% by mass in the polybutylene terephthalate resin composition. More preferably, it is 5-25 mass%. When a semicrystalline copolymerized polyester resin (C) is blended within this range, a semicrystalline copolymerized polyester resin (C) is compared with a polybutylene terephthalate resin composition containing the same amount of polyester elastomer (B). Bonding strength can be increased by adding. At the same time, the deflection temperature under load of the polybutylene terephthalate resin composition is also at a satisfactory level. If the content exceeds 50% by mass, although the bonding strength is improved, the heat resistance is lowered, which is not preferable.

[Inorganic filler (D)]
In the polybutylene terephthalate resin composition of the present invention, for the purpose of improving heat resistance and rigidity, (D) an inorganic filler can be blended in the range in which the effects of the present invention are not impaired. (D) Inorganic fillers include fibrous fillers and non-fibrous fillers, and as fibrous fillers used in the present invention, glass fibers, carbon fibers, potassium titanate fibers, silica / alumina fibers And zirconia fibers and metal fibers, but glass fibers are preferred.

  As the glass fiber, any known glass fiber is preferably used, and the glass fiber diameter, the shape of a circle, a wedge-shaped cross section, an oval cross section or the like, or the length and glass cut when used for manufacturing a chopped strand or roving It does not depend on the method of In the present invention, the type of glass is not limited, but in terms of quality, E glass or a corrosion resistant glass containing a zirconium element in the composition is preferably used.

  In the present invention, in order to improve the interface characteristics between the fibrous filler and the resin matrix, a fibrous filler surface-treated with an organic treating agent such as an aminosilane compound or an epoxy compound is preferably used. As the aminosilane compound and the epoxy compound used for the fibrous filler, any known ones can be preferably used, and the types of the aminosilane compound and the epoxy compound used for the surface treatment of the fibrous filler in the present invention are preferably used. Not dependent

  Examples of plate-like and particulate non-fibrous inorganic fillers include glass beads, glass flakes, silica, kaolin, talc, mica, wollastonite, titanium oxide, zinc oxide, alumina, calcium carbonate and magnesium carbonate. From the viewpoint of the balance of impact resistance, fluidity, and product appearance, glass beads, kaolin, talc and mica are preferable, and kaolin and mica are more preferable. Since a plate-like or granular non-fibrous inorganic filler can not obtain sufficient strength when used alone, it is preferable to use it in combination with a fibrous filler.

  The content of the inorganic filler (D) in the polybutylene terephthalate resin composition is 0 to 60% by mass, preferably 5 to 55% by mass, and more preferably 10 to 55% by mass. By blending the inorganic filler (D) within this range, it is possible to obtain a polyester elastomer bondable polybutylene terephthalate resin composition which does not impair the bonding strength with the polyester elastomer and which has improved heat resistance and rigidity. It becomes possible.

[Other additives]
In addition, various known additives can be added to the polybutylene terephthalate resin composition of the present invention, as needed, as long as the characteristics of the present invention are not impaired. Examples of known additives include colorants such as pigments, release agents, heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, plasticizers, modifiers, antistatic agents, flame retardants, dyes and the like. It can be mentioned.
As a mold release agent, a long chain fatty acid or its ester or metal salt, an amide based compound, polyethylene wax, silicone, polyethylene oxide and the like can be mentioned. The long chain fatty acid preferably has 12 or more carbon atoms in particular, and examples thereof include stearic acid, 12-hydroxystearic acid, behenic acid, montanic acid, etc. Partial or whole carboxylic acid is esterified with monoglycol or polyglycol Or a metal salt may be formed. Examples of the amide compounds include ethylene bisterephthalamide, methylene bisstearylamide and the like. These release agents may be used alone or as a mixture.
These various additives can be contained up to 5% by mass in total when the polybutylene terephthalate resin composition is 100% by mass. That is, it is preferable that the sum total of said (A), (B), (C), (D) is 95-100 mass% in 100 mass% of polybutylene terephthalate resin compositions.

[Polybutylene terephthalate resin composition]
As a manufacturing method for producing the polybutylene terephthalate resin composition of the present invention, after blending in any blending sequence with the above blending composition, they are mixed and melt-kneaded using a tumbler or Henschel mixer or the like. The melt-kneading method can be any method known to those skilled in the art, and a single screw extruder, a twin screw extruder, a kneader, a Banbury mixer, a roll, etc. can be used, among which a twin screw extruder is used. It is preferable to do. Further, in order to remove volatile components and low molecular weight components decomposed during processing, it is desirable to perform suction with a vacuum pump between the side port of the glass fiber feeding portion and the die head of the extruder tip.

The polybutylene terephthalate resin composition of the present invention is for molded articles for welding polyester elastomers, and in particular for molded articles for welding polyester elastomers by insert molding.
The polybutylene terephthalate resin composition of the present invention can be formed into a molded article by a known molding method such as injection molding. This molded body can be used for the composite material described below.

[Composite material]
Hereinafter, a composite molded article obtained by welding a molded article made of the polybutylene terephthalate resin composition of the present invention and a polyester elastomer will be described. This composite molded body is obtained by arranging a molded body made of a polybutylene terephthalate resin composition as an insert material in a mold, and welding a polyester elastomer by injection molding. In insert molding, a material (insert material) disposed in a mold is called a primary material, and in the present invention, a molded article made of a polybutylene terephthalate resin composition corresponds to this. In the mold in which the insert material is placed, the material to be injected is referred to as a secondary material, and in the present invention, polyester elastomer corresponds.

  The polyester elastomer of the secondary material may be the same as or different from the polyester elastomer (B) used for the primary material described above. The polyester elastomer of the secondary material is not particularly limited, but the polyester elastomer (B) used for the primary material described above can be used. The hardness (surface hardness) of the secondary material polyester elastomer is preferably 25 to 40 Shore D hardness. It is a preferred embodiment to use the same kind of soft segment as the secondary material polyester elastomer and the polyester elastomer (B) used for the primary material.

  The reason why the molded product made of the polybutylene terephthalate resin composition of the primary material and the polyester elastomer of the secondary material show excellent bonding (welding) properties by insert molding is considered as follows. In the primary material, the polyester elastomer (B) is contained in a specific amount, so that the polyester elastomer (B) dispersed in a sea-island structure in the polybutylene terephthalate resin (A) is introduced as a secondary material It is considered that the polyester elastomer melted on the heat of fusion and the dispersed polyester elastomer on the primary material side and the polyester elastomer on the secondary material side are mixed to provide adhesion. By containing the copolyester resin (C), it is considered that the polybutylene terephthalate resin (A) in the primary material becomes easy to move and mixing is more likely to occur.

  The composite material of the present invention can be used for air ducts, bearings, rollers, covers, various housings, connectors, grips, casters, etc., taking advantage of its characteristics.

  Although the present invention will be specifically described using Examples and Comparative Examples, the present invention is not limited thereto. In addition, the measured value described in the Example is measured by the following method.

(1) Intrinsic viscosity of a polybutylene terephthalate resin and a copolyester resin A sample of 0.1 g is dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane (mass ratio 6/4) and measured at 30 ° C. using a Ubbelohde viscosity tube did. (Unit: dl / g)
(2) Reduced viscosity of polyester elastomer 0.05 g of a sample was dissolved in 25 ml of a mixed solvent (phenol / tetrachloroethane = 60/40 (mass ratio)), and measured at 30 ° C. using an Ostwald viscometer. (Unit: dl / g)
(3) Hardness of polyester elastomer (surface hardness)
It measured according to JIS K 7215 (-1986). The test piece is made of three injection moldings (length 100 mm, width 100 mm, thickness 2 mm) prepared at a cylinder temperature of 240 ° C. and a mold temperature of 50 ° C. The value after 5 seconds from the start of measurement was taken as the D hardness (Shore D hardness).

(4) Preparation of a half dumbbell of polybutylene terephthalate resin composition for insert molding The polybutylene terephthalate resin composition pellet obtained by compounding was subjected to an injection molding machine (J110AD-110H manufactured by Japan Steel Works, Ltd.), cylinder temperature = 230 The half shape of the tensile test dumbbell according to ISO3167 was obtained at ° C, mold temperature = 50 ° C, injection speed = 50 mm / sec, holding pressure 40 MPa.
(5) Insert molding After attaching the half dumbbell of the ISO tensile test obtained above to the ISO tensile test dumbbell molding die cavity, polyester elastomer is injection molded of the remaining dumbbell part at a cylinder temperature of 230 ° C. to obtain polybutylene terephthalate resin An ISO tensile test dumbbell in which the composition and the polyester elastomer were joined (welded) at the center was obtained. The polyester elastomer (B-2) shown below was used as a polyester elastomer.
(6) Evaluation of bondability An ISO tensile test dumbbell in which the polybutylene terephthalate resin composition obtained above and a polyester elastomer were joined at the central part was measured according to ISO-527-1.2, and the dumbbell was broken. The elongation (%) was determined, and the state of the polyester elastomer was further evaluated.
In the above tensile test, when the test piece after the test having an elongation of 30% or more was confirmed, the polyester elastomer was adhered to the joint portion of the polybutylene terephthalate composition, and the trace of the joint was confirmed. Therefore, in the case of the elongation of 30% or more, it was judged that the bonding site has sufficient bonding strength.

(7) Flexural strength, flexural modulus Measured according to ISO-178.
(8) Charpy impact strength Measured according to JIS K7111.
(9) Deflection temperature under load Measured according to JIS K7191. The load was at 0.45 MPa.
(10) Cooling temperature (Tc2)
Using a differential scanning calorimeter (DSC), each sample was enclosed in a DSC apparatus in a dry state with a moisture content of 0.03% by mass or less, and measurement was performed to prevent fluctuations due to moisture. That is, the temperature is raised to 300.degree. C. at a temperature rising rate of 20.degree. C./min under a nitrogen stream, held at that temperature for 5 minutes, and then lowered to 100.degree. C. at a rate of 10.degree. The top temperature of the crystallization peak of was determined.
(11) Melting point (Tm)
Using a differential scanning calorimeter (DSC), each sample was enclosed in a DSC apparatus in a dry state with a moisture content of 0.03% by mass or less, and measurement was performed to prevent fluctuations due to moisture. That is, the peak temperature (° C.) when the temperature was raised to 300 ° C. at a temperature rising rate of 20 ° C./min under a nitrogen stream was taken as the melting point (Tm). Those with no melting point peak in this measurement were judged to be amorphous.

The blending components used in Examples and Comparative Examples are shown below.
Polybutylene terephthalate resin (A);
(A-1) Polybutylene terephthalate resin: Toyobo Co., Ltd. intrinsic viscosity 0.83 dl / g
(A-2) Polybutylene terephthalate resin: Toyobo Co., Ltd. intrinsic viscosity 1.30 dl / g (A-3) Polybutylene terephthalate resin: Toyobo Co., Ltd. intrinsic viscosity 0.68 dl / g

Polyester elastomer (B);
(B-1) Polyester elastomer with TPA // BD / PTMG (number average molecular weight 1000) of 100 / 71.8 / 28.2 (mol%): Melting point 172 ° C., reduced viscosity 2.22 dl / g, Acid value 35 eq / ton, D hardness 38
(B-2) Polyester elastomer with TPA // BD / PTMG (number average molecular weight 2000) of 100 // 75/25 (mol%): Melting point 180 ° C., reduced viscosity 2.50 dl / g, acid value 21 eq / Ton, D hardness is 31

Semicrystalline copolyester resin (C);
(C-1) Copolymer having a composition ratio of TPA / IPA // BD = 70/30 // 100 (mol%): Prototype of Toyobo Co., Ltd., Toyobo Byron (registered trademark), melting point temperature 178 ° C., inherent Viscosity 0.73 dl / g
(C-2) Copolymer having a composition ratio of TPA / IPA // BD = 45/55 // 100 (mol%): trial product of Toyobo Co., Ltd., Toyobo Byron (registered trademark), melting point temperature 136 ° C., specific Viscosity 0.76 dl / g

Amorphous polyester resin;
(C-3) Amorphous Copolymer Polyester Resin, Copolymer with Composition Ratio of TPA // EG / NPG = 100 // 70/30 (Mole%): Prototype of BYONO (Toyobo Co., Ltd.) , Glass transition temperature 75 ° C, Intrinsic viscosity 0.83 dl / g
(C-4) Amorphous copolymerized polyester resin, copolymer of TPA / IPA // EG / NPG = 50/50 // 50/50 (mol%) composition ratio: Toyobo Co., Ltd., Byron (registered trademark) ) Prototype, glass transition temperature 67 ° C, intrinsic viscosity 0.53dl / g
(The abbreviations of the raw material monomers are as follows: TPA: terephthalic acid, BD: 1,4-butanediol, PTMG: polyoxy tetramethylene glycol, IPA: isophthalic acid, EG: ethylene glycol, NPG: neopentyl glycol )

Inorganic filler (D);
(D-1) Glass fiber (average fiber length 3 mm, average fiber diameter 11 μm): T-120H (manufactured by Nippon Electric Glass Co., Ltd.)
(D-2) Mica (average particle size 23 μm): A-21S (manufactured by Yamaguchi Mica Co., Ltd.)

Other additives;
Antioxidant 1: Irganox 1010 (Cibas Specialty Chemicals Inc.)
Antioxidant 2: Seanox 412S (manufactured by Cipro Chemical Industries, Ltd.)
Release agent: WE40 (manufactured by Clariant Japan)

Examples 1 to 14 and Comparative Examples 1 to 9
Each component was blended with a tumbler so as to obtain the compositions shown in Tables 1 and 2, and then melt-kneaded with a twin-screw extruder (using STS 35 manufactured by Copellion Co., Ltd.) to obtain composition pellets.
The resulting composition pellets were dried and then evaluated by the method described above. Physical property evaluations (7) to (10) were performed on the polybutylene terephthalate resin composition, and bonding property evaluation (6) was performed on the composite molded body. The results are shown in Tables 1 and 2.

From Table 1, the following can be seen. With respect to Comparative Example 1, in Examples 1 to 6, as the addition amount of the semicrystalline copolyester resin increases, the adhesion improvement is recognized. On the other hand, although the improvement of adhesiveness is seen also by Comparative Examples 2-5, the fall of deflection temperature under load is large. When the temperature-fall crystallization temperature is compared, it can be seen that when the semi-crystalline copolyester resin is used, the temperature drop is small, so the drop in deflection temperature under load is small. That is, it is understood that, by using the semicrystalline copolyester resin, it is possible to improve the bondability while suppressing the decrease in deflection temperature under load.
Furthermore, according to Table 2, according to the results of Examples 7, 2, 8 and Comparative Examples 6, 3, 7, the addition amounts of the polyester elastomer are not dependent, and Examples 2, 9, 10, Comparative Examples 3, 8, From the results of 9, it is understood that the effect of suppressing the decrease in deflection temperature under load is exhibited regardless of the amount of the inorganic filler. From the results of Examples 11, 12, 13, and 14, it is understood that the effect of suppressing the decrease in deflection temperature under load is exhibited regardless of the type of inorganic filler, the viscosity of polybutylene terephthalate resin, and the type of polyester elastomer.

  From the above, in the polybutylene terephthalate resin composition of the primary material, by adding a predetermined amount or more of the polyester elastomer, sufficient bonding (welding) with the polyester elastomer of the secondary material while maintaining the characteristics of the polybutylene terephthalate resin It is possible to give a sex. Further, addition of the semi-crystalline copolyester resin lowers Tc2 and the molecular motion of the polybutylene terephthalate resin is activated even with the same amount of heat when the polyester elastomer is welded, so bonding (welding with the polyester elastomer of the same amount) ) Has improved. Under the present circumstances, it became clear that it is possible to suppress the fall of the deflection temperature under load which becomes a contradiction of adhesive improvement by non-crystalline and semicrystalline copolyester resin.

The resin composition of the present invention has a bonding strength sufficient for practical use as compared with a conventional polybutylene terephthalate resin composition, and therefore is useful as a molding material for a joinable molded article by insert molding with a polyester elastomer.

Claims (5)

  10 to 95% by mass of polybutylene terephthalate resin (A), 4 to 42% by mass of polyester elastomer (B), 1 to 50% by mass of semicrystalline copolyester resin (C) and 0 to 60% of inorganic filler (D) A polybutylene terephthalate resin composition containing 1% by weight, which is for a molded article for welding a polyester elastomer.   The polybutylene terephthalate according to claim 1, wherein the semicrystalline copolyester resin (C) is a polyester resin obtained by copolymerizing at least one of an alkyl side chain-containing glycol and isophthalic acid with an ethylene terephthalate unit or a butylene terephthalate unit. Resin composition.   The polybutylene terephthalate resin composition according to claim 1, wherein the semicrystalline copolyester resin (C) is a polyester resin obtained by copolymerizing at least one of an alkyl side chain-containing glycol and isophthalic acid with a butylene terephthalate unit.   The composite molded object by which the molded object and polyester elastomer which consist of a polybutylene-terephthalate-resin composition in any one of Claims 1-3 were welded.   The manufacturing method of the composite molded object which distributes the molded object which consists of a polybutylene-terephthalate-resin composition in any one of Claims 1-3 as insert material in a metal mold | die, and welds a polyester elastomer by injection molding.