JP2007186553A - Resin composition, molded product, method for producing molded product - Google Patents

Abstract

A composition containing a polybutylene terephthalate resin having excellent laser welding characteristics is provided.
(A) To 100 parts by weight of a polybutylene terephthalate resin obtained by using a titanium compound as a catalyst and having a titanium concentration of 90 ppm or less as titanium atoms, (c) an antioxidant 0.001-1. A polybutylene terephthalate resin composition for laser welding, comprising 5 parts by weight.
[Selection figure] None

Description

 The present invention relates to a polybutylene terephthalate resin composition for laser welding. The present invention also relates to a molded product using the resin composition and a method for producing the molded product.

Polybutylene terephthalate resin (PBT resin) is excellent in heat resistance, chemical resistance, electrical properties, and mechanical properties, and is widely used as an industrial resin. In recent years, among the various uses, development has progressed to products that seal electric circuit parts such as automobile electrical parts (control unit, etc.), various sensor parts, connector parts, and the like. Adhesives, ultrasonic welding, hot plate welding, etc. are used as the sealing method, but the adhesive method has problems of environmental impact such as surrounding pollution in addition to the time loss until curing. Ultrasonic welding, hot plate welding, and the like have problems such as vibration, damage to the product due to heat, and post-treatment due to generation of wear powder and burrs.
On the other hand, laser welding is non-contact, does not generate wear powder or burrs, and has little damage to the product. However, since the PBT resin generally has a low laser beam transmittance, it has to be reduced in thickness, and the margin for designing the thickness of the product is narrow. For this reason, when the laser output is increased, there is a risk of inconveniences such as melting on the laser incident surface, smoke generation, and bubbles due to abnormal heat generation at the bonding interface.

 As a problem after welding, there is a problem of hydrolyzability under heat and humidity resistance, and it is generally known that the polyester resin has a higher hydrolysis resistance as the terminal carboxyl group concentration is higher (for example, non-patent document). 1). Also in the PBT resin, the higher the terminal carboxyl group concentration, the greater the hydrolysis reaction rate under wet heat, leading to a decrease in molecular weight due to hydrolysis, and a decrease in mechanical properties. In particular, although the welded portion is temporary, it receives a high-temperature thermal history due to laser irradiation, so that the molecular weight is reduced and hydrolysis tends to proceed.

 In order to solve the above problem, it is widely practiced to reduce the terminal carboxyl group concentration by solidifying the PBT resin obtained by melt polymerization once and solid-phase polymerization at a temperature below the melting point (for example, , See Patent Document 1). However, since melt polymerization is usually performed at a temperature equal to or higher than the melting point of the PBT resin, even if the terminal carboxyl group concentration is reduced by solid phase polymerization, the terminal carboxyl group concentration rises again at the time of molding, and when it becomes a molded product. The problem that the effect of solid-phase polymerization becomes small remains.

 On the other hand, a method of using a polybutylene terephthalate copolymer to control the melting point and widen the welding condition width is known (Patent Document 2). However, the improvement in transmittance by this method is small, and improvement in the product thickness design margin cannot be expected. Further, there is a method of blending an amorphous resin or an elastomer with a polybutylene terephthalate resin (Patent Documents 3 and 4). By using this method, the transmittance may be improved, but the problem remains that the transmittance is likely to vary depending on the formulation and molding conditions.

Saturated polyester resin handbook (December 22, 1989, published by Nikkan Kogyo Shimbun, pages 192-193) JP-A-9-316183 Japanese Patent No. 3510817 Japanese Patent Laid-Open No. 2003-292752 JP 2004-315805 A

 The present invention has been made in view of the above circumstances, and the object thereof is a composition containing a PBT resin excellent in laser welding characteristics (PBT resin composition (laser welding agent) for laser welding), and the resin composition. An object of the present invention is to provide a molded article or the like that is firmly bonded by laser welding using an object.

As a result of intensive studies to solve the above problems, the present inventors have surprisingly solved the above problems easily by adopting a composition containing a specific PBT resin and an antioxidant. As a result, the present invention has been completed.
The present invention has been completed based on the above findings, and the gist is as follows (1) to (7).
(1) (c) Antioxidant 0.001-1.5 with respect to 100 parts by weight of polybutylene terephthalate resin obtained by using titanium compound as a catalyst and containing titanium concentration of 90 ppm or less as titanium atom A polybutylene terephthalate resin composition for laser welding, including parts by weight.
(2) The resin composition according to (1), further comprising (b) a reinforcing filler.
(3) One or more antioxidants selected from the group consisting of (c) an antioxidant, (c1) a phenolic antioxidant, (c2) a sulfurous antioxidant, and (c3) a phosphorus antioxidant. The resin composition according to (1) or (2), which is an agent.
(4) The resin composition according to any one of (1) to (3), wherein the terminal carboxyl group concentration of the (a) polybutylene terephthalate resin is 40 μeq / g or less.
(5) The resin composition according to any one of (1) to (4), further comprising (d) a colorant.
(6) A molded article obtained by welding a member made of the resin composition according to any one of (1) to (5) and a member made of the second resin composition using a laser beam.
(7) A molded article comprising a step of welding a member made of the resin composition according to any one of (1) to (5) and a member made of the second resin composition using a laser beam. Manufacturing method.

 The resin composition of the present invention is excellent in laser welding characteristics such as thermal stability, hydrolysis resistance, and laser transmission. Therefore, the resin composition of the present invention can be suitably used for electric and electronic parts, automobile parts and the like. Furthermore, a molded article strongly bonded by laser welding using the resin composition of the present invention is provided, and the industrial value of the present invention is remarkable.

  Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

Resin composition <(a) PBT resin>
The PBT resin used in the present invention has a structure in which a terephthalic acid unit and a 1,4-butanediol unit are ester-bonded, 50 mol% or more of the dicarboxylic acid component is composed of terephthalic acid units, and 50 mol% or more of the diol component is 1 , A polymer composed of 4-butanediol units. The proportion of terephthalic acid units in all dicarboxylic acid components is preferably 70 mol% or more, more preferably 80 mol% or more, particularly preferably 95 mol% or more, and the proportion of 1,4-butanediol units in all diol components is Preferably, it is 70 mol% or more, more preferably 80 mol% or more, and particularly preferably 95 mol% or more. When the amount of terephthalic acid units or 1,4-butanediol units is less than 50 mol%, the crystallization rate of PBT is lowered, and moldability is deteriorated.

 The dicarboxylic acid component other than terephthalic acid in the PBT resin used in the present invention is not particularly limited and can be used. For example, phthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenylether dicarboxylic acid, 4,4′-benzophenone dicarboxylic acid, 4,4′-diphenoxyethanedicarboxylic acid, 4,4 ′ -Arocyclic dicarboxylic acids such as diphenylsulfone dicarboxylic acid, aromatic dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid And aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid. These dicarboxylic acid components can be introduced into the polymer backbone as dicarboxylic acids or as dicarboxylic acid derivatives such as dicarboxylic acid esters and dicarboxylic acid halides. These dicarboxylic acids or derivatives thereof may be used alone or in combination of two or more.

 There is no restriction | limiting in particular in diol components other than 1, 4- butanediol in PBT resin used by this invention. For example, ethylene glycol, diethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, polypropylene glycol, polytetramethylene glycol, dibutylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6 -Aliphatic diols such as hexanediol, 1,8-octanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4-cyclohexanedimethylol, etc. Examples thereof include aromatic diols such as diol, xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4-hydroxyphenyl) propane, and bis (4-hydroxyphenyl) sulfone. These diol components may use only 1 type and may use 2 or more types together.

 In the PBT resin used in the present invention, hydroxycarboxylic acids such as lactic acid, glycolic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 6-hydroxy-2-naphthalenecarboxylic acid, p-β-hydroxyethoxybenzoic acid and the like are further included. Monofunctional components such as acids, alkoxycarboxylic acids, stearyl alcohol, benzyl alcohol, stearic acid, benzoic acid, tert-butylbenzoic acid, benzoylbenzoic acid, tricarbaric acid, trimellitic acid, trimesic acid, pyromellitic acid, gallic acid Trifunctional or polyfunctional components such as trimethylolethane, trimethylolpropane, glycerol and pentaerythritol can be used as the copolymerization component.

 The PBT resin used in the present invention can be obtained by using a titanium catalyst as a catalyst in the esterification reaction (or transesterification reaction) between 1,4-butanediol and terephthalic acid (or dialkyl terephthalate). is there.

 As the titanium catalyst, a titanium compound is used. Specific examples thereof include inorganic titanium compounds such as titanium oxide and titanium tetrachloride, titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate and tetrabutyl titanate, and tetraphenyl titanate. Examples include titanium phenolate. Among these, tetraalkyl titanate is preferable, and tetrabutyl titanate is more preferable.

 A tin catalyst may be used in combination with the titanium catalyst. Tin is used as a tin compound, and specific examples thereof include dibutyltin oxide, methylphenyltin oxide, tetraethyltin, hexaethylditin oxide, cyclohexahexyl distinoxide, didodecyltin oxide, triethyltin hydroxide, triethyltin Phenyltin hydroxide, triisobutyltin acetate, dibutyltin diacetate, diphenyltin dilaurate, monobutyltin trichloride, tributyltin chloride, dibutyltin sulfide, butylhydroxytin oxide, methylstannic acid, ethylstannic acid, butylstannic acid It is done.

 In addition to magnesium catalysts, magnesium compounds such as magnesium acetate, magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium alkoxide, magnesium hydrogen phosphate, calcium acetate, calcium hydroxide, calcium carbonate, calcium oxide, calcium alkoxide Side, calcium compounds such as calcium hydrogen phosphate, antimony compounds such as antimony trioxide, germanium compounds such as germanium dioxide and germanium tetroxide, manganese compounds, zinc compounds, zirconium compounds, cobalt compounds, orthophosphoric acid, phosphorous acid, Phosphorous acid, polyphosphoric acid, phosphorus compounds such as esters and metal salts thereof, and reaction aids such as sodium hydroxide and sodium benzoate may be used.

The PBT resin used in the present invention is a PBT resin obtained using a titanium compound as a catalyst, and is a PBT resin having a content of 90 ppm or less, preferably 60 ppm or less, more preferably 50 ppm or less as titanium atoms. Titanium content is the weight ratio of atoms to PBT resin.
The lower limit of the titanium content is preferably 1 ppm, more preferably 3 ppm, still more preferably 5 ppm, particularly preferably 8 ppm, more preferably 15 ppm.
When the content of titanium is more than 90 ppm, the color tone, hydrolysis resistance, transparency, moldability and the like are deteriorated, and foreign matters are also increased. Moreover, there exists a tendency for polymerizability to become favorable by making content of titanium into 1 ppm or more.

In the present invention, as described above, a tin catalyst can be used in combination with the titanium catalyst. Generally, a tin catalyst has a lower catalytic ability than a titanium catalyst, so that it is necessary to increase the amount of addition compared to a titanium catalyst. However, if the amount of tin catalyst used is too large, the color tone tends to deteriorate, and tin is also toxic. Therefore, the dosage of tin catalyst is usually 100 ppm or less, preferably 50 ppm or less, more preferably 20 ppm or less, and most preferably no tin catalyst is used.
The content of titanium atoms and the like can be measured using a method such as atomic emission, atomic absorption, Inductively Coupled Plasma (ICP) after recovering the metal in the polymer by a method such as wet ashing.

 The intrinsic viscosity of the PBT resin used in the present invention is preferably 0.60 to 2.00 dL / g, more preferably 0.65 to 1.50 dL / g, and still more preferably 0.68 to 1.30 dL / g. . By setting the intrinsic viscosity to 0.60 dL / g or more, the mechanical strength of the molded product becomes better, and by setting it to 2.00 dL / g or less, the melt viscosity becomes too high and the fluidity deteriorates. , Tending to more effectively prevent the moldability from deteriorating. The intrinsic viscosity is a value measured at 30 ° C. using a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1).

The resin composition of the present invention may contain two or more PBT resins having different intrinsic viscosities. In this case, it is preferable that the intrinsic viscosity of the two or more PBT resins to be used is within the above range.
Moreover, it is preferable that the intrinsic viscosity as a resin composition of this invention is also in said range. For example, a PBT resin having an intrinsic viscosity of 0.6 to 0.90 dL / g and a PBT resin having an intrinsic viscosity of 0.91 to 1.5 dL / g are mixed at a weight ratio of 5:95 to 95: 5. Are used.

 The terminal carboxyl group concentration of the PBT resin used in the present invention is preferably 40 μeq / g or less, more preferably 35 μeq / g or less, still more preferably 33 μeq / g or less, and particularly preferably 30 μeq / g or less. Further, the lower limit is preferably 0.1 μeq / g or more, more preferably 1 μeq / g or more. By setting the terminal carboxyl group concentration to 40 μeq / g or less, deterioration of hydrolysis resistance of the PBT resin tends to be suppressed. As a method for adjusting the terminal carboxyl group concentration, a method for adjusting polymerization conditions such as a raw material charge ratio at the time of polymerization, a polymerization temperature, a pressure reduction method, a method for reacting a terminal blocker, or the like may be applied.

Even if the terminal carboxyl group concentration of the PBT resin is low, if the terminal carboxyl group concentration is increased by heat during kneading or molding, the hydrolysis resistance of the molded product (product) is only deteriorated as a result. In addition, generation of a gas such as tetrahydrofuran (THF) is caused in the molten resin state during kneading and molding. In order to suppress degradation of the hydrolysis resistance of such a molded product and gas generation during melting, it is preferable to use a PBT resin in which the increase in terminal carboxyl group concentration during melting is smaller. Specifically, the terminal carboxyl group concentration is preferably increased when the moisture in the resin is dried to 500 ppm or less and then heat-treated at 245 ° C. for 40 minutes in an inert gas atmosphere such as nitrogen, helium, or argon. It is preferable to use a PBT resin of 0.1 to 30 μeq / g, more preferably 1 to 10 μeq / g, and still more preferably 1 to 8 μeq / g. In general, the lower the content of the catalyst substance and the higher the molecular weight, the smaller the increase in the terminal carboxyl group concentration when heat is applied.
In the above evaluation method, the moisture concentration was specified because the hydrolysis reaction occurred when the moisture concentration was high, and the accurate decomposition behavior could not be grasped, and the temperature and time were specified because the temperature was If the time is too low or the time is too short, the rate of increase of the terminal carboxyl group concentration is too small. Another reason is that when the evaluation is performed at an extremely high temperature, side reactions other than the generation of the terminal carboxyl group are accompanied and the evaluation becomes inaccurate.

 The terminal carboxyl group concentration of the PBT resin can be determined by dissolving the PBT resin in an organic solvent and titrating it using an alkali solution such as a sodium hydroxide solution.

 The solution haze of the PBT resin used in the present invention is not particularly limited, but is preferably a solution haze when measured by dissolving 2.7 g of PBT resin in 20 mL of a phenol / tetrachloroethane mixed solvent (weight ratio 3/2). It is 10% or less, more preferably 5% or less, further preferably 3% or less, particularly preferably 1% or less, and most preferably 0.5% or less. By setting the solution haze to 10% or less, there is a tendency that foreign matters are further reduced and the transmittance is also improved. The solution haze tends to increase when the catalyst content is high or the deactivation of the catalyst is large.

Next, the manufacturing method of PBT resin used by this invention is demonstrated. The PBT resin used in the present invention can be produced, for example, according to the description in JP-A No. 2004-307794.
Specifically, the production method of the PBT resin is roughly divided into a so-called direct polymerization method using a dicarboxylic acid as a main raw material and a transesterification method using a dialkyl dicarboxylate as a main raw material. The former is different in that water is produced in the initial esterification reaction, and the latter is produced in the initial transesterification reaction.

 Moreover, the production method of PBT resin is roughly divided into a batch method and a continuous method, depending on the raw material supply or polymer discharge form. The initial esterification reaction or transesterification reaction is carried out in a continuous operation, and the subsequent polycondensation is carried out in a batch operation. Conversely, the initial esterification reaction or transesterification reaction is carried out in a batch operation, followed by polycondensation. There is also a method of performing the above in a continuous operation.

 In the production of the PBT resin used in the present invention, the direct polymerization method is used from the viewpoints of obtaining the raw material stability, ease of distillate treatment, high raw material cost, and the effects of the present invention more remarkably. preferable. In the production of the PBT resin used in the present invention, from the viewpoint of productivity and stability of product quality and the improvement effect of the present invention, the raw material is continuously supplied, and the esterification reaction or transesterification reaction is continuously performed. It is preferable to adopt the method of performing. And in manufacture of PBT resin used by this invention, it is preferable to employ | adopt what is called the continuous method which also performs the polycondensation reaction following esterification reaction or transesterification reaction continuously.

 In the production of the PBT resin used in the present invention, in the esterification reaction vessel, at least a part of 1,4-butanediol is esterified independently of terephthalic acid (or dialkyl terephthalate) in the presence of a titanium catalyst. A step of continuously esterifying (or transesterifying) terephthalic acid (or dialkyl terephthalate) and 1,4-butanediol while being supplied to the tank (or transesterification reaction tank) is preferably employed.

 That is, in the production of the PBT resin used in the present invention, haze and foreign matters derived from the catalyst are reduced, and the catalytic activity is not lowered. In addition to 4-butanediol, it is preferable to supply 1,4-butanediol to the esterification reaction vessel or transesterification reaction vessel independently of terephthalic acid or dialkyl terephthalate. Hereinafter, the 1,4-butanediol may be referred to as “separately supplied 1,4-butanediol”.

 The “separately supplied 1,4-butanediol” can be applied with fresh 1,4-butanediol independent of the process. "Separately supplied 1,4-butanediol" collects 1,4-butanediol distilled from the esterification reaction tank or transesterification reaction tank with a condenser or the like and holds it as it is or in a temporary tank or the like Then, it can be refluxed to the reaction vessel, or can be supplied as 1,4-butanediol having a purity improved by separating and purifying impurities. Hereinafter, “separately supplied 1,4-butanediol” composed of 1,4-butanediol collected by a condenser or the like may be referred to as “recycled 1,4-butanediol”. From the viewpoint of effective utilization of resources and simplicity of equipment, it is preferable to apply “recycled 1,4-butanediol” to “separately supplied 1,4-butanediol”.

 In addition, 1,4-butanediol distilled from the esterification reaction tank or transesterification reaction tank usually contains components such as water, alcohol, THF, dihydrofuran in addition to the 1,4-butanediol component. . Therefore, the 1,4-butanediol distilled above can be separated and purified from components such as water, alcohol and tetrahydrofuran after being collected by a condenser or the like, and returned to the reaction vessel. preferable.

 In the production of the PBT resin used in the present invention, it is preferable that 10% by weight or more of “separately supplied 1,4-butanediol” is directly returned to the reaction liquid phase part. Here, the reaction liquid phase part refers to the liquid phase side of the gas-liquid interface in the esterification reaction tank or transesterification reaction tank. To return directly to the reaction liquid phase part, use piping or the like. "Separately supplied 1,4-butanediol" indicates that it is directly supplied to the liquid phase part without going through the gas phase part. The ratio of returning directly to the liquid phase part of the reaction liquid is preferably 30% by weight or more, more preferably 50% by weight or more, particularly preferably 80% by weight or more, and most preferably 90% by weight or more. By setting the “separately supplied 1,4-butanediol” to be directly returned to the liquid phase part of the reaction liquid to 30% by weight or more, foreign matter tends to be reduced.

 The temperature of “separately supplied 1,4-butanediol” when returning to the reactor is usually 50 to 220 ° C., preferably 100 to 200 ° C., and more preferably 150 to 190 ° C. When the temperature of “separately supplied 1,4-butanediol” is too high, the amount of by-product of THF tends to increase, and when it is too low, the heat load tends to increase, which tends to cause energy loss.

 Further, in the production of the PBT resin used in the present invention, haze and foreign matters derived from the catalyst are reduced, and the catalytic activity is not lowered. Therefore, among the titanium catalysts used for the esterification reaction (or transesterification reaction), 10 It is preferable to feed at least% by weight directly to the reaction liquid phase part independently of terephthalic acid (or dialkyl terephthalate). Here, the reaction liquid phase part indicates the liquid phase side of the gas-liquid interface in the esterification reaction tank or transesterification reaction tank, and the direct supply to the reaction liquid phase part uses a pipe, etc. This means that the catalyst is supplied directly to the liquid phase part without going through the gas phase part of the reactor. The proportion of the titanium catalyst supplied directly to the reaction liquid phase is preferably 30% by weight or more, more preferably 50% by weight or more, particularly preferably 80% by weight or more, and most preferably 90% by weight or more.

 The above titanium catalyst can be dissolved in a solvent or the like, and can be directly supplied to the reaction liquid phase part of the esterification reaction tank or transesterification reaction tank without being dissolved. In order to reduce adverse effects such as heat denaturation from the heat medium jacket, it is preferable to dilute with a solvent such as 1,4-butanediol. The concentration at this time is usually 0.01 to 20% by weight, preferably 0.05 to 10% by weight, and more preferably 0.08 to 8% by weight, as the concentration of the titanium catalyst with respect to the entire solution. Further, from the viewpoint of further reducing foreign matters, the water concentration in the solution is usually 0.05 to 1.0% by weight. The temperature for preparing the solution is usually 20 to 150 ° C., preferably 30 to 100 ° C., more preferably 40 to 80 ° C., from the viewpoint of preventing deactivation and aggregation. Moreover, it is preferable to mix a catalyst solution with an additional supply 1, 4- butanediol and piping etc., and to supply to an esterification reaction tank or a transesterification reaction tank from a point of deterioration prevention, precipitation prevention, and foreign material control.

 An example of a continuous method employing a direct polymerization method is as follows. That is, the dicarboxylic acid component containing terephthalic acid unit as a main component and the diol component containing 1,4-butanediol unit as a main component are mixed in a raw material mixing tank to form a slurry, and one or a plurality of esterification reaction tanks In the presence of a titanium catalyst, the temperature is usually 180 to 260 ° C., preferably 200 to 245 ° C., more preferably 210 to 235 ° C., and usually 10 to 133 kPa, preferably 13 to 101 kPa, more preferably 60 to Under a pressure of 90 kPa, usually 0.5 to 10 hours, preferably 1 to 6 hours, the esterification reaction is continuously carried out, and the resulting oligomer as an esterification reaction product is transferred to a polycondensation reaction tank, In the presence of the polycondensation catalyst in the polycondensation reactor (s), preferably continuously, usually 210-280 ° C., preferably 220 265 ° C. temperature, usually 27kPa or less, preferably 20kPa or less, more preferably in the following reduced pressure 13 kPa, under agitation, usually 2 to 10 hours, preferably for polycondensation reaction at 2-5 hours. The polymer obtained by the polycondensation reaction is usually transferred from the bottom of the polycondensation reaction tank to a polymer extraction die and extracted in the form of a strand. And so on.

 An example of a continuous process employing the transesterification process is as follows. That is, in the transesterification reaction tank or tanks, in the presence of the titanium catalyst, usually 110 to 260 ° C, preferably 140 to 245 ° C, more preferably 180 to 220 ° C, and usually 10 to 133 kPa, Preferably, the transesterification is carried out continuously under a pressure of 13 to 120 kPa, more preferably 60 to 101 kPa, usually for 0.5 to 5 hours, preferably 1 to 3 hours. In the presence or absence of a polycondensation reaction catalyst, preferably continuously in the presence or absence of a polycondensation reaction catalyst, usually 210-280 ° C, preferably 220-265 ° C. Temperature, usually 27 kPa or less, preferably 20 kPa or less, more preferably 13 kPa or less, under reduced pressure, with stirring, usually 2 to 12 hours, Mashiku causes polycondensation reaction at 3-10 hours.

<(B) Reinforcing filler>
You may mix | blend a reinforcement filler with the PBT resin composition of this invention. The reinforcing filler is not particularly limited, but examples thereof include glass fibers, carbon fibers, silica / alumina fibers, zirconia fibers, boron fibers, boron nitride fibers, silicon nitride potassium titanate fibers, metal fibers and other inorganic fibers, aromatics Examples thereof include organic fibers such as polyamide fibers and fluororesin fibers. These reinforcing fillers can be used in combination of two or more. Among the above reinforcing fillers, inorganic fillers, particularly glass fibers, are preferably used.

 (B) When the reinforcing filler is an inorganic fiber or an organic fiber, the average fiber diameter is not particularly limited, but is preferably 1 to 100 μm, more preferably 2 to 50 μm, still more preferably 3 to 30 μm, particularly preferably. 5 to 20 μm. The average fiber length is not particularly limited, but is preferably 0.1 to 20 mm, more preferably 1 to 10 mm.

 (B) The reinforcing filler may be used after being surface-treated with a sizing agent or a surface treatment agent in order to improve interfacial adhesion with the PBT resin. Examples of the sizing agent or surface treatment agent include functional compounds such as epoxy compounds, acrylic compounds, isocyanate compounds, silane compounds, and titanate compounds. The reinforcing filler can be surface-treated in advance with a sizing agent or a surface treatment agent, or can be surface-treated by adding a sizing agent or a surface treatment agent during the preparation of the PBT resin composition. . The addition amount of the reinforcing filler is preferably 100 parts by weight or less, more preferably 5 to 70 parts by weight with respect to 100 parts by weight of the PBT resin.

 Another filler can be mix | blended with the PBT resin composition of this invention with a reinforcing filler. Other fillers to be blended include, for example, plate-like inorganic fillers, ceramic beads, wollastonite, talc, clay, mica, zeolite, kaolin, potassium titanate, barium sulfate, titanium oxide, silicon oxide, aluminum oxide, Examples thereof include magnesium hydroxide. By blending the plate-like inorganic filler, the anisotropy and warpage of the molded product can be reduced. Examples of the plate-like inorganic filler include glass flakes, mica, and metal foil. Among these, glass flakes are preferably used.

<(C) Antioxidant>
The PBT resin composition of the present invention contains (c) an antioxidant. As the antioxidant, one or more antioxidants selected from the group consisting of (c1) phenolic antioxidants, (c2) sulfur antioxidants, and (c3) phosphorus antioxidants may be blended. preferable.
The blending amount of the antioxidant is 0.001 to 1.5 parts by weight, preferably 0.03 to 1 part by weight, based on 100 parts by weight of (a) PBT resin.

 The (c1) phenolic antioxidant used in the present invention refers to an antioxidant having a phenolic hydroxyl group. (C1) The phenolic antioxidant is preferably a hindered phenolic antioxidant. A hindered phenol antioxidant is an antioxidant in which one or two carbon atoms adjacent to a carbon atom of an aromatic ring to which a phenolic hydroxyl group is bonded are substituted by a substituent having 4 or more carbon atoms. An agent. The substituent having 4 or more carbon atoms may be bonded to a carbon atom of the aromatic ring by a carbon-carbon bond, or may be bonded via an atom other than carbon.

Examples of the (c1) phenolic antioxidant used in the present invention include p-cyclohexylphenol, 3-t-butyl-4-methoxyphenol, 4,4′-isopropylidenediphenol, 1,1-bis (4-hydroxy). Non-hindered phenolic antioxidants such as phenyl) cyclohexane, 2-t-butyl-4-methoxyphenol, 2,6-di-t-butyl-p-cresol, 2,4,6-tri-t-butylphenol 4-hydroxymethyl-2,6-di-t-butylphenol, styrenated phenol, 2,5-di-t-butylhydroquinone, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) ) Propionate, triethylene glycol bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propiate Onate], 1,6-hexanediol bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], pentaerythritol tetrakis [3- (3,5-di-t-butyl-4 -Hydroxyphenyl) propionate], 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (6-t-butyl-4-ethylphenol), 2,2'-methylenebis [4-Methyl-6- (1,3,5-trimethylhexyl) phenol], 4,4′-methylenebis (2,6-di-t-butylphenol), 4,4′-butylidenebis (3-methyl-6) -T-butylphenol), 2,6-bis (2-hydroxy-3-t-butyl-5-methylbenzyl) -4-methylphenol, 1,1,3-tris [2 Methyl-4-hydroxy-5-t-butylphenyl] butane, 1,3,5-trimethyl-2,4,6-tris [3,5-di-t-butyl-4-hydroxybenzyl] benzene, tris ( 3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, tris [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate, 4,4′- Thiobis (3-methyl-6-tert-butylphenol), 2,2'-thiobis (4-methyl-6-tert-butylphenol), 4,4'-thiobis (2-methyl-6-tert-butylphenol), thiobis And hindered phenolic antioxidants such as (β-naphthol).
In particular, hindered phenol-based antioxidants can be suitably used as radical trapping agents because they tend to be stable radicals themselves. The molecular weight of the hindered phenol antioxidant is usually 200 or more, preferably 500 or more, and the upper limit is usually 3000.

 (C1) The amount of the phenolic antioxidant is preferably 0.001 to 1.5 parts by weight, more preferably 0.03 to 1 part by weight, based on 100 parts by weight of (a) PBT resin. By making the content of the phenolic antioxidant 0.001 part by weight or more, the antioxidant effect is more effectively exhibited, and by making the content 1.5 parts by weight or less, the oxidation heat stability is deteriorated. In addition to the tendency to suppress, it becomes possible to make the decomposition of the resin during melt-kneading less likely to occur.

The (c2) sulfur-based antioxidant used in the present invention refers to an antioxidant having a sulfur atom, such as didodecylthiodipropionate, ditetradecylthiodipropionate, dioctadecylthiodipropionate, pentaerythritol. Tetrakis (3-dodecylthiopropionate), thiobis (N-phenyl-β-naphthylamine), 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, nickel dibutyldithiocarbamate , Nickel isopropyl xanthate, trilauryl trithiophosphite and the like. In particular, a thioether-based antioxidant having a thioether structure can be suitably used because it receives oxygen from an oxidized substance and reduces it.
The molecular weight of the sulfur-based antioxidant is usually 200 or more, preferably 500 or more, and the upper limit is usually 3000.

The (c3) phosphorus antioxidant used in the present invention refers to an antioxidant having a phosphorus atom, and is preferably an antioxidant having a P (OR) ₃ structure. Here, R is preferably an alkyl group, an alkylene group, an aryl group or an arylene group, and three Rs may be the same or different, and any two Rs may be bonded to each other to form a ring structure. It may be formed.
(C3) Specific examples of phosphorus antioxidants include triphenyl phosphite, diphenyl decyl phosphite, phenyl diisodecyl phosphite, tri (nonylphenyl) phosphite, bis (2,4-di-t-butyl). Phenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, and the like.

 (C2) Sulfur-based antioxidant and / or (c3) Phosphorus-based antioxidant more effectively improves the heat aging resistance of the PBT resin composition of the present invention, and retains color tone, tensile strength, elongation, etc. It has the effect of further improving the rate. In the PBT resin composition of the present invention, the contents of (c2) sulfur-based antioxidant and (c3) phosphorus-based antioxidant are preferably 0.001 to 100 parts by weight of (a) PBT resin, respectively. The amount is 1.5 parts by weight, more preferably 0.03 to 1 part by weight. By making the content of the antioxidant 0.001 part by weight or more, the antioxidant effect is better exhibited, and by making the content 1.5 parts by weight or less, the deterioration of oxidation heat stability is further suppressed. At the same time, it becomes possible to make the decomposition of the resin during melt-kneading less likely to occur.

<(D) Colorant>
You may mix | blend (d) colorants, such as dye and a pigment, with the PBT resin composition of this invention.
As the dye, oil-soluble dyes and disperse dyes such as anthraquinone, perylene, perinone, monoazo, methine, and phthalocyanine can be preferably used.
As the pigment, both inorganic pigments and organic pigments can be preferably used. Examples of inorganic pigments include oxides, sulfides, sulfates, and carbon black. Examples of organic pigments include azo, phthalocyanine, anthraquinone, perylene, perinone, quinacridone, and dioxazine.
(D) The compounding amount of the colorant is preferably 0.005 to 5 parts by weight, more preferably 0.01 to 1 part by weight with respect to 100 parts by weight of (a) PBT resin.

<Other additives>
Other additives may be added to the PBT resin composition of the present invention without departing from the spirit of the present invention.
Examples of other additives include flame retardants, heat stabilizers, lubricants, mold release agents, catalyst deactivators, crystal nucleating agents, and crystallization accelerators. These additives can be added during or after the polymerization of (a) PBT resin. Furthermore, in order to give desired performance to (a) PBT resin, you may mix | blend a ultraviolet absorber, a weather resistance stabilizer, an antistatic agent, a foaming agent, a plasticizer, an impact resistance improving agent, etc.

 The type of flame retardant is not particularly limited, and examples thereof include organic halogen compounds, antimony compounds, phosphorus compounds, other organic flame retardants, and inorganic flame retardants. Examples of the organic halogen compound include brominated polycarbonate, brominated epoxy resin, brominated phenoxy resin, brominated polyphenylene ether resin, brominated polystyrene resin, brominated bisphenol A, and pentabromobenzyl polyacrylate. Examples of the antimony compound include antimony trioxide, antimony pentoxide, and sodium antimonate. Examples of the phosphorus compound include phosphoric acid ester, polyphosphoric acid, ammonium polyphosphate, and red phosphorus. Examples of other organic flame retardants include nitrogen compounds such as melamine and cyanuric acid. Examples of other inorganic flame retardants include aluminum hydroxide, magnesium hydroxide, silicon compound, and boron compound.

 The amount of these additives is preferably 10 to 50 parts by weight per 100 parts by weight of (a) PBT resin.

In addition to the above, the PBT resin composition of the present invention includes a polyethylene resin, a polypropylene resin, a polystyrene resin, a polyacrylonitrile resin, a polymethacrylic ester resin, and an acrylonitrile butadiene styrene resin within the scope not departing from the gist of the present invention. (ABS resin), polycarbonate resin, polyamide resin, polyphenylene sulfide resin, polyethylene terephthalate resin, liquid crystal polyester resin, polyacetal resin, polyphenylene oxide resin and other thermoplastic resins, phenol resin, melamine resin, silicone resin, epoxy resin, etc. A functional resin may be blended. These thermoplastic resins and thermosetting resins may be used in combination of two or more.
The compounding amount of these resins is preferably 0.1 to 50 parts by weight with respect to 100 parts by weight of (a) PBT resin.

 The blending method of the various additives and resins is not particularly limited, but a method of using a uniaxial or biaxial extruder having equipment capable of devolatilization from the vent port as a kneader is preferable. Each component including an additional component may be supplied to the kneader in a lump or sequentially. Moreover, you may mix the 2 or more types of component chosen from each component including an additional component previously.

 The molding method of the PBT resin composition of the present invention is not particularly limited, and molding methods generally used for thermoplastic resins, that is, molding methods such as injection molding, hollow molding, extrusion molding, and press molding are applied. I can do it. In this case, a particularly preferable molding method is injection molding because of good fluidity. In the injection molding, the resin temperature is preferably controlled to 240 to 280 ° C.

The PBT resin composition of the present invention can be used as a PBT resin member having excellent laser welding characteristics. In particular, members mainly composed of PBT resin can be firmly bonded to each other, and can be preferably used for producing a molded product having two or more PBT resin members.
The shape of the member is not particularly limited. However, since the members are joined and used by laser welding, the shape usually has at least a contact portion (plane, curved surface) of the surface.
In laser welding, laser light that has passed through a laser-transmitting member is absorbed by the laser-absorbing member, melted, and both members are welded. Since the PBT resin composition of the present invention has high permeability to laser light, it can be preferably used as a member that transmits laser light. Here, the thickness of the member through which the laser is transmitted (thickness in the direction in which the laser beam is transmitted) can be appropriately determined in consideration of the application, the composition of the composition, and the like, and is, for example, 5 mm or less, preferably 4 mm. It is as follows.

As a laser light source used for laser welding of the present invention, for example, gas laser such as Ar laser (510 nm), He—Ne laser (630 nm), CO ₂ laser (10600 nm), and liquid laser such as dye laser (400 to 700 nm). Solid-state lasers such as YAG laser (1064 nm), semiconductor lasers (655 to 980 nm), and the like can be used. A semiconductor laser is preferably used in terms of beam quality and cost. Further, the laser type can be appropriately selected depending on the type of the welding partner material.

More specifically, for example, when welding a member made of the PBT resin composition of the present invention and a member made of the second resin composition, first, the welded portions are brought into contact with each other. At this time, surface contact is desirable between the welded portions of the two, and may be flat surfaces, curved surfaces, or a combination of flat and curved surfaces. Next, laser light is irradiated from the member side made of the PBT resin composition of the present invention (preferably irradiated perpendicularly to the adhesive surface). At this time, the laser beam may be condensed at the interface between the two using a lens system if necessary. The beam passes through the member made of the PBT resin composition of the present invention, is absorbed near the surface of the member made of the second resin composition, generates heat, and melts. Next, the heat is transferred to the member made of the PBT resin composition of the present invention by heat conduction and melted to form a molten pool at the interface between the two, and after cooling, both are joined.
The molded product in which the members are welded in this way has high bonding strength. In addition, the molded product in the present invention means a product in which at least two or more members are welded, and includes a member that forms a part of these in addition to a finished product or a part.

The member made of the second resin composition is not particularly limited as long as it contains at least a resin and can be welded to the member made of the PBT resin composition of the present invention. The resin contained in the second resin composition is preferably a thermoplastic resin, for example, an olefin resin, a vinyl resin, a styrene resin, an acrylic resin, a polyester resin, a polyamide resin, or a polycarbonate resin. Polyacetal resins and the like, and polyester resins, polyamide resins, and polycarbonate resins are preferably used from the viewpoint of good compatibility. Moreover, the 2nd resin composition may be comprised from 1 type, or 2 or more types of resin. Furthermore, the PBT resin composition of the present invention may be used.
In addition, the resin contained in the second resin composition preferably has an absorption wavelength within the range of the wavelength of the laser beam to be irradiated. Furthermore, you may make the 2nd resin composition add the light absorption agent, for example, a coloring pigment, etc., and may express the absorption characteristic. Examples of the color pigment include inorganic pigments (black pigments such as carbon black (for example, acetylene black, lamp black, thermal black, furnace black, channel black, ketjen black), red pigments such as iron oxide red, molyb Examples include orange pigments such as date orange, white pigments such as titanium oxide, and organic pigments (yellow pigments, orange pigments, red pigments, blue pigments, green pigments, etc.) Among them, inorganic pigments generally have a strong hiding power and are lasers. It can be preferably used by the second resin composition on the absorption side, and these light absorbers may be used alone or in combination of two or more.
It is preferable that the compounding quantity of these light absorbers is 0.01-1 weight part with respect to 100 weight part of resin components.

 The molded product obtained in the present invention has high welding strength and less damage to the resin due to laser light irradiation. Therefore, it is used in various applications such as electric / electronic parts, office automate (OA) equipment parts, and home appliances. It can be applied to parts, mechanical mechanism parts, automobile mechanism parts and the like. In particular, it can be suitably used for automobile electrical parts (various control units, ignition coil parts, etc.), motor parts, various sensor parts, connector parts, switch parts, relay parts, coil parts, transformer parts, lamp parts, and the like.

 EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example at all unless the summary is exceeded. In addition, the measurement method of the physical property and evaluation item which were employ | adopted in the following examples is as follows.

(1) Titanium concentration in PBT resin Wetly decompose PBT resin with high-purity sulfuric acid and nitric acid for electronic industry, and measure using high resolution ICP (Inductively Coupled Plasma) -MS (Mass Spectrometer) (manufactured by ThermoQuest) did.

(2) Intrinsic viscosity (IV)
It calculated | required in the following way using the Ubbelohde type viscometer. That is, using a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1), at 30 ° C., the dropping time of only the polymer solution having a concentration of 1.0 g / dL and the solvent was measured and obtained from the following formula.

[IV] = ((1 + 4K _H η _sp ) ^0.5 −1) / (2K _H C)
In the above formula, η _sp = (η / η ₀ ) −1, η is the polymer solution dropping time, η ₀ is the solvent dropping time, C is the polymer solution concentration (g / dL), and K _H is Huggins Is a constant. K _H adopted the 0.33.

(3) Terminal carboxyl group concentration 0.5 g of PBT resin was dissolved in 25 mL of benzyl alcohol, and titrated using a 0.01 mol / L benzyl alcohol solution of sodium hydroxide.

(4) Solution haze (solution Haze)
After dissolving 2.70 g of PBT resin in 110 mL of a mixed solvent of phenol / tetrachloroethane = 3/2 (weight ratio) at 110 ° C. for 30 minutes, the mixture was cooled in a constant temperature water bath at 30 ° C. for 15 minutes, and Nippon Denshoku Co., Ltd. Using a turbidimeter (NDH-300A), the cell length was 10 mm. It shows that transparency is so favorable that a value is low.

(5) Light transmittance Resin compositions of Examples or Comparative Examples molded using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd .: Model SE-50D) at a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C. A flat plate having a size of 13 × 125 mm and a thickness of 2 mmt was prepared. The light transmittance of this substrate was measured with a visible / ultraviolet spectrophotometer (manufactured by Shimadzu Corporation: UV-3100PC). For the light transmittance, the ratio of the transmitted light intensity and the incident light intensity in the near infrared region 800 to 1100 nm was expressed in terms of 100 fractions.

(6) Heat aging resistance Using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd .: model SG-75MIII) at a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C., from the resin compositions of the examples or comparative examples. An ISO test piece was prepared. Further, the ISO test piece was treated in a hot air oven at 150 ° C. for 500 hours.
About these ISO test pieces, the color tone b value, the tensile strength, and the tensile elongation at break were measured. The b value (yellow index) indicates that the lower the value, the less yellowing and the better the color tone. The b value was measured using a spectrocolorimeter (Konica Minolta, Inc .: CM-3600d) at the center of the ISO test piece chuck. Δb (increase in b value) was determined according to the following equation.
Δb = (b value of ISO test piece after treatment) − (b value of ISO test piece before treatment)
Furthermore, according to ISO527, the tensile strength and the tensile breaking elongation of the ISO test piece before and after a process were measured.
Moreover, the tensile strength retention was calculated | required according to following Formula.
Tensile strength retention (%) = (Tensile strength after treatment / Tensile strength before treatment) × 100

(7) Hydrolysis resistance The above ISO tensile test piece was wet-heat treated for a predetermined time at 203 ° C. in 121 ° C. and saturated steam. The tensile strength of the ISO tensile test piece before and after the treatment was measured according to ISO 527, and the strength retention was obtained. When the resin composition containing no reinforcing filler is used for the wet heat treatment (Examples 1 to 7, Comparative Examples 1 to 3), the resin composition containing the reinforcing filler is used for 60 hours (Example 8). 9, Comparative Example 4, 5), 100 hours.

(8) Laser welding strength evaluation As shown in FIG. 1, the test pieces were overlapped and irradiated with laser. In FIG. 1, (a) shows a view of the test piece from the side, and (b) shows a view of the test piece from above. Reference numeral 1 denotes a test piece made of the resin composition of the example or comparative example, 2 denotes a test piece made of the second resin composition which is a mating material to be joined, and 3 denotes a laser irradiation spot.
The test piece 1 made of the resin composition used in the light transmittance measurement was overlapped with the laser transmission side, and the test piece 2 made of the second resin composition was overlapped with the laser absorption side, and the laser was irradiated from the transmission side. The laser welding apparatus was FD-100 manufactured by Fine Devices, the wavelength of the laser beam was 840 nm, and the focal spot diameter was 0.6 mm.
In the case of a resin composition not containing a reinforcing filler (Examples 1 to 7, Comparative Examples 1 to 3), in the case of a material containing a reinforcing filler at a laser output of 15 W and a scanning speed of 4 mm / sec (Examples 8 and 9). Comparative Examples 4 and 5), scanning with a laser output of 20 W and a scanning speed of 4 mm / sec was performed in the width direction (13 mm). The laser welding strength was measured by using a tensile tester (Instron type 5544) and the tensile speed was 5 mm / sec. The tensile strength is indicated by the tensile shear fracture strength of the welded portion.
The test piece uses an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd .: model SE-50D), and the resin composition and the second resin composition of the present invention or the example are each subjected to a cylinder temperature of 250 ° C., The molds were molded into flat plates of 13 × 125 mm and a thickness of 2 mmt, respectively, at a mold temperature of 80 ° C.

[raw materials]
(A) Polybutylene terephthalate resin (PBT resin)
(A1) Production Method of PBT Resin a1 According to paragraphs 0081 to 0083 of JP-A No. 2004-307794 and the esterification step shown in FIG. 1, and polycondensation step shown in paragraph No. 0087 of FIG. 4 and FIG. The PBT resin was manufactured in the following manner.
First, a PBT oligomer having an esterification rate of 99% is preliminarily mixed through a raw material supply line from a slurry preparation tank with a slurry at 60 ° C. mixed at a ratio of 1.80 mol of 1,4-butanediol to 1.00 mol of terephthalic acid. It supplied continuously to the reaction tank for esterification which has the filled screw type stirrer so that it might become 41 kg / 1 hour (henceforth "h").
At the same time, the bottom component of the rectification column at 185 ° C. is supplied from the recirculation line at 17.2 kg / h, and 1,4-butanediol containing 6.0% by weight of tetrabutyl titanate at 65 ° C. is used as the catalyst from the catalyst supply line. The solution was fed at 97 g / h. This feed is 30 ppm relative to the theoretical polymer yield. The water content in this solution was 0.20% by weight.

 The internal temperature of the reaction vessel is 230 ° C., the pressure is 78 kPa, and the generated water, tetrahydrofuran, and excess 1,4-butanediol are distilled from the distillation line, and the high-boiling and low-boiling components are separated in the rectification column. Separated. The high-boiling component at the bottom of the column after the system is stabilized is 98% by weight or more of 1,4-butanediol, and a part of the high-boiling component is externally extracted through the extraction line so that the liquid level of the rectification column is constant. Extracted. On the other hand, low-boiling components were extracted from the top of the column in the form of gas, condensed with a condenser, and extracted to the outside from the extraction line so that the liquid level in the tank was constant.

 A fixed amount of the oligomer generated in the reaction tank was extracted from the extraction line using a pump, and the liquid level was controlled so that the average residence time of the liquid in the reaction tank was 3.3 hours. The oligomer extracted from the extraction line was continuously supplied to the first polycondensation reaction tank. After the system was stabilized, the esterification rate of the oligomer collected at the outlet of the reaction vessel was 97.5%.

 The internal temperature of the first polycondensation reaction tank was 240 ° C., the pressure was 2.1 kPa, and the liquid level was controlled so that the residence time was 120 minutes. An initial polycondensation reaction was performed while extracting water, tetrahydrofuran, and 1,4-butanediol from a vent line connected to a decompressor. The extracted reaction liquid was continuously supplied to the second polycondensation reaction tank.

 The internal temperature of the second polycondensation reaction tank is 245 ° C., the pressure is 130 Pa, and the liquid level is controlled so that the residence time is 90 minutes. From the vent line connected to the decompressor, water, tetrahydrofuran, 1,4- The polycondensation reaction was further advanced while extracting butanediol. The obtained polymer was continuously extracted in a strand form from the die head via an extraction line by an extraction gear pump, and was cut with a rotary cutter.

 The polymer obtained had (2) intrinsic viscosity (IV) of 0.85 and (3) terminal carboxyl group concentration of 12.2 μeq / g. Other analytical values are summarized in Table 1. A PBT resin having few foreign matters, excellent color tone, good transparency and excellent thermal stability was obtained.

(A2) Production method of PBT resin a2 In (a1), the same procedure as (a1) was performed except that the polycondensation step shown in paragraph No. 0089 of Japanese Patent Application Laid-Open No. 2004-307794 and FIG. 6 was adopted. At this time, the process up to the second polycondensation reaction tank was performed under the same conditions as in (a1), the internal temperature of the third polycondensation reaction tank was 240 ° C., the pressure was 130 Pa, and the residence time was 60 minutes. A PBT resin having few foreign matters, excellent color tone, good transparency, excellent thermal stability, and a higher molecular weight than (a1) was obtained. The analytical values are summarized in Table 1.

(A3) Method for producing PBT resin a3 In a 200-liter stainless steel reaction vessel equipped with a turbine-type stirring blade, dimethyl terephthalate (DMT) 272.9 mol, 1,4-butanediol 327.5 mol, tetrabutyl titanate 0 .101 mol (theoretical yield of 100 ppm per titanium as the amount of titanium) was charged and sufficiently substituted with nitrogen. Subsequently, the temperature of the system was raised, and after 60 minutes, at a temperature of 210 ° C. and atmospheric pressure under nitrogen, a transesterification reaction was performed for 2 hours while distilling methanol, 1,4-butanediol, and THF generated out of the system. . The reaction start time was the time when a predetermined temperature and a predetermined pressure were reached.

 After transferring the oligomer obtained above to a stainless steel reactor having an internal volume of 200 L having a vent pipe and a double helical stirring blade, it was allowed to reach a temperature of 245 ° C. and a pressure of 100 Pa over 60 minutes. A time polycondensation reaction was performed. After completion of the reaction, the polymer was extracted into a strand shape and cut into a pellet shape. The polymer obtained had (2) intrinsic viscosity of 1.26 and (3) terminal carboxyl group concentration of 19.7 μeq / g. The analytical values are summarized in Table 1.

(A4) Manufacturing method of PBT resin a4 (comparative example)
In a 200 L stainless steel reaction vessel equipped with a turbine type stirring blade, 272.9 mol of terephthalic acid, 491.3 mol of 1,4-butanediol, 0.126 mol of tetrabutyl titanate (theoretical yield: 100 ppm per polymer as the amount of titanium) The charge was sufficiently replaced with nitrogen. Subsequently, the temperature of the system was raised, and after 60 minutes, the temperature reached 220 ° C. and the pressure of 80 kPa, and the generated water, THF, and excess 1,4-butanediol were distilled out of the system for 2.0 hours. It was made to react. The reaction start time was the time when a predetermined temperature and a predetermined pressure were reached. At this point, a part of the sample was taken and the esterification rate was measured and found to be 99%.

 After transferring the oligomer obtained above to a stainless steel reactor having an internal volume of 200 L having a vent pipe and a double helical stirring blade, it was allowed to reach a temperature of 245 ° C. and a pressure of 100 Pa over 60 minutes. The polycondensation reaction was performed for 5 hours. After completion of the reaction, the polymer was extracted into a strand shape and cut into a pellet shape. The obtained polymer (2) had an intrinsic viscosity of 0.85, and (3) the terminal carboxyl group concentration was as high as 44.5 μeq / g, and was inferior in thermal stability. The analysis values are summarized in Table 1.

(A5) Production method of PBT resin a5 (comparative example)
A 200 L stainless steel reaction vessel equipped with a turbine-type stirring blade was charged with 272.9 mol of dimethyl terephthalate (DMT), 327.5 mol of 1,4-butanediol, and 0.126 mol of tetrabutyl titanate and sufficiently substituted with nitrogen. . The amount of titanium was 100 ppm per theoretical yield polymer. Subsequently, the temperature of the system was raised, and after 60 minutes, at a temperature of 210 ° C. and atmospheric pressure under nitrogen, a transesterification reaction was performed for 2 hours while distilling methanol, 1,4-butanediol, and THF generated out of the system. . The reaction start time was the time when a predetermined temperature and a predetermined pressure were reached.

 After transferring the oligomer obtained above to a stainless steel reactor having an internal volume of 200 L having a vent pipe and a double helical stirring blade, it was allowed to reach a temperature of 245 ° C. and a pressure of 100 Pa over 60 minutes. The polycondensation reaction was performed for 5 hours. After completion of the reaction, the polymer was extracted into a strand shape and cut into a pellet shape. The obtained polymer (2) had an intrinsic viscosity of 0.85, and (3) the terminal carboxyl group concentration was as high as 37.4 μeq / g, and was inferior in thermal stability. The analytical values are summarized in Table 1.

(B) Reinforcing filler: Glass fiber (Nippon Electric Glass, T-187, average fiber diameter 13 μm, average fiber length 3 mm)

(C) Antioxidant (c1) Pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (trade name: Irganox 1010, manufactured by Ciba Specialty Chemicals)
(C2) Pentaerythritol tetrakis (3-dodecylthiopropionate) (Cipro Kasei Co., Ltd., trade name: SEENOX412S)
(C3) Bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite (Asahi Denka Kogyo Co., Ltd., trade name: ADK STAB PEP36)

(D) Colorant: Thermoplastic resin (masterbatch) produced by blending a colorant containing a methine-based oil-soluble dye and a PBT resin (eBIND LTW-8950C manufactured by Orient Chemical Industries)

Second resin composition: The PBT resin composition of Example 8 described later was mixed with 0.6 parts by weight of carbon black with respect to 100 parts by weight of PBT resin.

[Examples 1-7, Comparative Examples 1-3]
(A) PBT resin and (c) antioxidant, and if necessary, (d) a colorant is blended so as to have the ratio shown in Table 2, and a twin screw extruder in which the cylinder temperature is set to 250 ° C. (Nippon Steel Works: TEX30C). The evaluation results are also shown in Table 2.

 As shown in Table 2, (1) the titanium concentration is 90 ppm or less, (3) the terminal carboxyl group concentration is 40 ppm or less, and (4) the solution Haze of the PBT resin is 10 ppm or less. By blending a specific antioxidant, it was possible to obtain a resin composition excellent in laser transmittance, heat aging resistance and hydrolysis resistance. By using this resin composition, it was confirmed that laser welding with other members was possible easily.

[Examples 8 and 9, Comparative Examples 4 and 5]
(A) PBT resin, (b) reinforcing filler, (c) antioxidant, and if necessary, (d) a coloring agent was blended in the ratio shown in Table 3, and the cylinder temperature was set to 250 ° C. The mixture was melt kneaded with a shaft extruder (manufactured by Nippon Steel Works: TEX30C). The evaluation results are also shown in Table 3.

 In Table 3, X indicates that no welding occurred. As shown in Table 3, even when (b) the reinforcing filler is added, (1) the titanium concentration is 90 ppm or less, (3) the terminal carboxyl group concentration is 40 ppm or less, and (4) of the PBT resin ) Using a PBT resin having a solution haze of 10 ppm or less and incorporating a specific antioxidant, a resin composition having excellent laser transmittance, heat aging resistance and hydrolysis resistance could be obtained. . By using this resin composition, it was confirmed that laser welding with other members was possible easily.

FIG. 1 is a schematic diagram showing test piece overlay and laser irradiation position in a laser welding strength test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Test piece which consists of PBT resin composition of this invention 2 Test piece which consists of 2nd resin composition 3 Laser irradiation location

Claims (7)

(A) With respect to 100 parts by weight of a polybutylene terephthalate resin obtained using a titanium compound as a catalyst and having a titanium concentration of 90 ppm or less as titanium atoms, (c) 0.001 to 1.5 parts by weight of an antioxidant A polybutylene terephthalate resin composition for laser welding. The resin composition according to claim 1, further comprising (b) a reinforcing filler. The (c) antioxidant is one or more antioxidants selected from the group consisting of (c1) phenolic antioxidants, (c2) sulfur antioxidants, and (c3) phosphorus antioxidants. The resin composition according to claim 1 or 2. The resin composition according to any one of claims 1 to 3, wherein a terminal carboxyl group concentration of the (a) polybutylene terephthalate resin is 40 µeq / g or less. Furthermore, the resin composition of any one of Claims 1-4 containing (d) a coloring agent. The molded article formed by welding the member which consists of a resin composition of any one of Claims 1-5, and the member which consists of a 2nd resin composition using a laser beam. The manufacturing method of a molded article including the process of welding the member which consists of a resin composition of any one of Claims 1-5, and the member which consists of a 2nd resin composition using a laser beam.

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