JP3740940B2 - Process for producing polybutylene terephthalate copolymer composition and polybutylene terephthalate copolymer composition obtained therefrom - Google Patents

Description

【００４３】
【表２】

表１より、実施例により得られた共重合体組成物は、耐熱老化性（色調変化△Ｅ）が優れていることが分かる。また、比較例１の製造方法によると耐熱老化性（色調変化△Ｅ）も劣っている上に、重縮合反応温度が高くても重合性が悪いことが分かる。更に比較例５の２種の酸化防止剤をコンパウンドしたものは、酸化防止剤の量が多いにもかかわらず、耐熱老化性（色調変化△Ｅ）が劣り、ブリードアウトも起こり、更に混練の熱劣化によりＩｚｏｄ衝撃強度が低下することが分かる。
【００４４】
【発明の効果】
本発明の製造方法によると、後工程を行うことなく、酸化防止剤が存在しても重合性を悪化させることなく、ポリブチレンテレフタレート共重合体組成物を製造することができる。また、得られたポリブチレンテレフタレート共重合体組成物は、ホモポリブチレンテレフタレートに比較しても結晶性が劣らず耐衝撃性、流動性、耐熱老化性（色調変化△Ｅ）が７未満と優れており、更に、酸化防止剤のブリードアウトがない優れた共重合体組成物である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a polybutylene terephthalate copolymer composition obtained by copolymerizing polytetramethylene ether glycol, which is reacted in the presence of a thioether antioxidant and a hindered phenol antioxidant from the reaction stage, and The present invention relates to a polybutylene terephthalate copolymer composition obtained.
[0002]
[Prior art]
Polybutylene terephthalate (hereinafter referred to as “PBT”) is a resin with an excellent balance of physical properties such as mechanical properties, electrical properties, and heat resistance, and is used as electrical and electronic components such as connectors and coil bobbins, and as automotive components such as distributor caps. Widely used.
[0003]
Among them, a resin having better fluidity has been required for molding applications in which the hinge parts of electrical parts and connectors are thin. For this reason, polytetramethylene ether glycol (polytetramethylene ether glycol (as a resin with excellent impact resistance and fluidity) that does not break or chip even in thin-walled parts and hinge parts of such molded products and does not break even when used under low temperature conditions. Hereinafter, a PBT copolymer obtained by copolymerizing “PTMG”) has been known.
[0004]
However, the PTMG component of the PBT copolymer obtained by copolymerizing PTMG has a problem that it is easily oxidized and deteriorated, and it was necessary to add an antioxidant to prevent this.
Conventionally, a method using a compound has been adopted to blend an antioxidant. However, in the method using a compound, in addition to an increase in the number of steps, there is a problem that the mechanical strength, particularly the Izod impact strength is lowered due to thermal deterioration in the extruder during compounding, and the molding is performed during use of the molded product. There was a problem that the antioxidant bleeds out on the surface of the product. In addition, in order to sufficiently exhibit the antioxidant effect, it is necessary to add a large amount of an antioxidant, and there is a problem that the cost is increased.
[0005]
On the other hand, JP-A-7-53697 discloses a method of adding an antioxidant to homo PBT during polymerization. However, in the case of implementation at a production scale in a plant, if an antioxidant is present during the polymerization reaction, the polymerization reaction is hindered due to the influence of the antioxidant, and the polymerizability deteriorates, resulting in a substantial increase. The degree of polymerization tends to be difficult, and PBT copolymerized with PTMG has a problem that the reaction inhibition tendency is larger because the total number of terminal groups of the reaction is smaller than that of homo PBT.
[0006]
[Problems to be solved by the invention]
In view of the problems of the prior art, the present invention does not inhibit the polymerization reaction even when the reaction is carried out in the presence of an antioxidant during the polymerization, and the compounding step of the additive is performed in the post-process after the polymerization. There is no need to do this, and even if the amount of antioxidant used is less than the amount of compound added, it has excellent heat aging resistance, and does not bleed out to the surface of the molded plate, resulting in mechanical deterioration resulting from thermal deterioration during compounding A method for producing a polybutylene terephthalate copolymer composition excellent in crystallinity and mechanical properties, and a polybutylene terephthalate copolymer composition obtained therefrom, which does not reduce strength, in particular, Izod impact strength. provide.
[0007]
[Means for Solving the Problems]
The present invention relates to a glycol component having 1,4-butanediol as a main component and a polytetramethylene ether glycol having a number average molecular weight of 650 to 2000 as a copolymerization component and a lower alkyl of a bifunctional carboxylic acid having dimethylterephthalic acid as a main component. In reacting an ester component with a titanium compound and a magnesium compound as a polymerization catalyst, and with a thioether antioxidant and a hindered phenol antioxidant present, the polyester component having a number average molecular weight of 650 to 2000 is reacted. The amount (A) of tetramethylene ether glycol is 3% by weight or more and 7% by weight or less, and the amount of thioether antioxidant (B) and the amount of hindered phenol antioxidant (C) are each 0.01% by weight. % To 0.5% by weight, and the relationship among A, B, and C satisfies Formula 1. It is present as a process for the preparation of polybutylene terephthalate copolymer composition characterized by reacting.
[0008]
[Expression 2]
9 <A / (B + C) <20 (Formula 1)
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
As a glycol component constituting the polybutylene terephthalate copolymer composition of the present invention, 1,4-butanediol is the main component, polytetramethylene ether glycol having a number average molecular weight of 650 to 2000 is a copolymer component, and bifunctional. The lower alkyl ester component of carboxylic acid is mainly composed of dimethyl terephthalic acid. The amount of polytetramethylene ether glycol having a number average molecular weight of 650 to 2000 must be 3 to 7% by weight. When used in this range, the crystallinity is not inferior to that of homopolybutylene terephthalate, and the impact resistance and fluidity are excellent.
[0010]
Lower alkyl ester components of bifunctional carboxylic acids other than dimethyl terephthalic acid include lower alkyl esters of aromatic dicarboxylic acids such as isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, adipic acid, sebacic acid, succinic acid, And lower alkyl esters of aliphatic dicarboxylic acids such as acids. These may be used alone or in combination of two or more, and can be arbitrarily selected according to the purpose. A small amount of trifunctional or higher functional carboxylic acid or carboxylic acid anhydride such as a small amount of trimellitic acid may be used.
[0011]
The polymerization catalyst used in the production method of the present invention is a titanium compound and a magnesium compound. The titanium compound is preferably a tetraalkyl titanate, specifically, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetra-t-butyl titanate, tetraphenyl titanate, tetracyclohexyl titanate and tetra-titanate. Examples include benzyl titanate or mixed titanates thereof. Of these, tetra-n-propyl titanate, tetraisopropyl titanate and tetra-n-butyl titanate are particularly preferable. Two or more of these titanium compounds may be used in combination. It is better to use as little titanium compound as possible. However, from the viewpoint of polymerizability, the amount of metallic titanium is preferably 30 to 200 ppm, preferably 40 to 130 ppm, particularly preferably 50 to 110 ppm, based on the polyester resin to be produced.
[0012]
Next, examples of the magnesium compound include magnesium acetate, magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium alkoxide, and magnesium hydrogen phosphate. Among these, magnesium acetate and magnesium hydroxide are preferable. Magnesium acetate is particularly preferable in terms of solubility in 4-butanediol (foreign matter generation) and the like.
[0013]
The amount of magnesium used is in the range of 0.5 to 2.0 mol of magnesium with respect to titanium as a metal. By using in this range, even if an antioxidant is added during polymerization, it can be produced without decreasing the polymerization rate. When this ratio is less than 0.5, the improvement in polymerization rate tends to be small, whereas when it exceeds 2.0, the polymerization rate tends to decrease. Preferably, it is 0.7 to 1.8, more preferably 0.85 to 1.7.
[0014]
In the production method of the present invention, a thioether antioxidant and a hindered phenol antioxidant are present and reacted. Any thioether-based antioxidant may be used as long as it has a thioether bond in the molecular structure, and examples thereof include dilauryl thiodipropionate, distearyl thiodipropionate, and 3-dodecylthiopropionic acid. Of these, pentaerythritol tetrakis (β-lauryl thiopropionate) is particularly preferable.
[0015]
Examples of the hindered phenol antioxidant include 2,4,6-tri-tert-butylphenol and 1,3,5-tris-methyl-2,4,6-tris (3,5-ditert-butyl- 4-hydroxy-benzyl) benzene and the like. Of these, tetrakis [methylene-3 (3,5-ditert-butyl-4-hydroxy-phenyl) propionate] methane is particularly preferred.
[0016]
The amount of the thioether-based antioxidant and the hindered phenol-based antioxidant used is 0.01% by weight or more and 0.5% by weight or less, respectively, and the polytetramethylene ether in the polybutylene terephthalate copolymer composition The relationship between the amount of glycol (A), the amount of thioether-based antioxidant (B), and the amount of hindered phenol-based antioxidant (C) must satisfy Formula 1.
[0017]
[Equation 3]
9 <A / (B + C) <20 (Formula 1)
If the amount of both antioxidants used is less than 0.01% by weight, the effect as an antioxidant is insufficient, and if it exceeds 0.5% by weight, it is not preferable in terms of cost. Moreover, if the relational expression of Formula 1 is not satisfied, the heat aging resistance is inferior and the mechanical strength is also lowered, which is not preferable.
[0018]
The production method of the present invention comprises a difunctional carboxylic acid mainly composed of 1,4-butanediol, a glycol component having a polytetramethylene ether glycol having a number average molecular weight of 650 to 2000 as a copolymer component and dimethylterephthalic acid as a main component. A transesterification step followed by a polycondensation in the presence of a titanium compound and a magnesium compound as a polymerization catalyst, and a thioether antioxidant and a hindered phenol antioxidant. It is produced via a reaction process. As manufacturing conditions, conventionally known conditions are employed.
[0019]
Specifically, for example, the raw material molar ratio of the alkylene glycol component and the lower alkyl ester component of the bifunctional carboxylic acid during the transesterification reaction is 2.0 or less, preferably in the range of 1.0 to 1.6. I do. Moreover, transesterification reaction temperature is 120-245 degreeC, Preferably it is 140-240 degreeC, and can be performed in 2 to 4 hours. The polycondensation reaction to be carried out is usually carried out under a reduced pressure of 0.399 Kpa or less and below 210 to 245 ° C. Preferably, it is 230-243.5 degreeC, More preferably, it is 230-240 degreeC or less. The polycondensation reaction time can be 2 to 5 hours. When the polycondensation reaction temperature is lower than 245 ° C., it is preferable to prevent deterioration of the resin due to shear heat generation during the latter stage of polymerization in which the degree of polymerization increases. When the polycondensation reaction temperature is 245 ° C. or higher, the added antioxidant tends to decompose or volatilize, and even if the added amount is large, the antioxidant ability tends to be inferior. In addition, the terminal vinyl group is greatly increased, and therefore the solid-phase polymerization rate is low and the productivity is lowered when solid-state polymerization is performed to further increase the degree of polymerization or to reduce gas and oligomerization. Sometimes it ends up.
[0020]
What is necessary is just to add the titanium compound as a polymerization catalyst at the time of the start of transesterification, during transesterification, after transesterification, and at the time of polycondensation reaction. Of these, it is preferable to add them separately at the start of transesterification and before the polycondensation reaction. In this case, a conventionally known method can be adopted as a method for adding the titanium compound. Specifically, it can be added directly as it is, or it can be diluted with 1,4-butanediol or an appropriate solvent used as a raw material.
[0021]
The magnesium compound is added either at the start of the transesterification, during the transesterification, after the transesterification, or during the polycondensation reaction. Of these, addition at the end of the transesterification and before the start of polymerization is preferred from the viewpoint of polymerization activity and color tone. A conventionally well-known method can be employ | adopted for the addition method of the magnesium compound in this case. Specifically, it can be added directly as it is, or dispersed in 1,4-butanediol or an appropriate solvent used as a raw material, and added as a slurry or dissolved.
[0022]
Next, the two antioxidants are added during the transesterification reaction or immediately before the polycondensation reaction. Preferably, it is added immediately before the polycondensation reaction. The method of adding these antioxidants is not particularly limited, a method of adding in the solid state such as powder or pellets, a method of heating above the melting point and adding as a melt, and a suitable solvent such as 1,4-butanediol Ordinary methods such as a method of dispersing it in a slurry and adding it as a slurry are employed.
[0023]
In the production method of the present invention, the reaction may be carried out in the presence of a small amount of other additives in addition to the polymerization catalyst and the two kinds of antioxidants. Other additives include hydrocarbon compounds such as microcrystalline wax as a mold release agent, talc as a nucleating agent, silicate compounds such as kaolin, core-shell rubber as a toughness improving agent, and fillers and reinforcing agents. Examples include charcoal cal and glass fiber.
[0024]
The polybutylene terephthalate copolymer composition obtained by the production method of the present invention can be subsequently subjected to solid phase polymerization according to a conventionally known method to obtain a final product. Specific solid-state polymerization conditions can usually be performed at a temperature of 180 to 220 ° C. under reduced pressure for about 3 to 20 hours.
The polybutylene terephthalate copolymer composition obtained by the production method of the present invention preferably has a heat aging resistance color change ΔE of less than 7. The color tone change ΔE is the L ₀ value, a ₀ value and b ₀ value of the color tone of the polybutylene terephthalate copolymer composition obtained, and the polybutylene terephthalate copolymer composition is heated at 150 ° C. for 200 hours. This is a value obtained from Equation 2 from the L value, the a value, and the b value of the color tone.
[0025]
[Expression 4]
ΔE = ((L−L ₀ ) ² + (a−a ₀ ) ² + (b−b ₀ ) ² ) ^0.5 (Formula 2)
If ΔE is less than 7, the color of the pellets by heat is good, and for example, parts used around the engine of automobiles, molded products having thin-walled parts or hinge parts of connectors, etc. It is preferable because cracks and chips due to deterioration hardly occur. On the other hand, if ΔE is 7 or more, the color is also brownish and unsuitable for use in molding. For example, parts used around engines such as automobiles and thin parts of connectors A molded product having a hinge part is not preferable because cracks and chips due to deterioration are likely to occur.
[0026]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples, unless the summary is exceeded. In addition, each measuring method in an Example and a comparative example is shown next.
<Intrinsic viscosity (η)>
The copolymer compositions obtained in Examples and Comparative Examples were dissolved at a concentration of 1 g / dl in a mixed solution in which phenol and 1,1,2,2-tetrachloroethane were mixed at a weight ratio of 1: 1. And measured at a temperature of 30 ° C. using an Ubbelohde viscometer. Further, the falling seconds of the solvent alone were measured, and the intrinsic viscosity (η) was determined from Equation 3.
[0027]
[Equation 5]
(Η) = ((1 + 4K _H η _sp ) ^0.5−1 ) / 2K _H C (Formula 3)
η _sp : η / η ₀₋₁
η: Solution dropping time η ₀ : Solvent dropping time C: Solute concentration (g / dl)
K _H : Haggins constant (use 0.33)
<Heat aging resistance (color change △ E)>
The color values of the copolymer composition chips obtained in Examples and Comparative Examples were measured for L value, a value, and b value using “Colorimetric Color Difference Meter” manufactured by Nippon Denshoku Industries Co., Ltd. Were designated as L ₀ , a ₀ and b ₀ , respectively.
[0028]
Moreover, the color tone L value, a value, and b value of the chip heated in an oven at 150 ° C. and air-dried for 200 hours were measured, and the measured values were taken as L, a, and b, respectively. From these values, ΔE was obtained from Equation 2.
[0029]
[Formula 6]
ΔE = ((L−L ₀ ) ² + (a−a ₀ ) ² + (b−b ₀ ) ² ) ^0.5 (Formula 2)
<Bleed-out>
150 mm × 150 mm × 3 mm flat plates were molded from the copolymer compositions obtained in the examples and comparative examples by an injection molding method. The plates were heated to 0.99 ° C. in Geer oven for 200 hours air dry surface to the bleed-out components of the flat plate were dissolved in d chloroform, the presence of two antioxidant was added to the reaction ¹ Confirmed by 1 H-NMR.
[0030]
<Izod impact strength>
Measurements were made according to ASTM D256 using a ½ inch thick notched specimen.
<Bending elastic modulus>
A 1/4 inch thick test piece was measured according to ASTM D790 with a distance between supporting points of 100 mm and a load cell speed of 3 mm / min.
[0031]
Example 1
1.2 parts mole 1,4-butanediol is added to 100 parts by weight of dimethyl terephthalate, 33 ppm of tetrabutyl titanate (based on the amount of polymer as titanium metal) is added, and the transesterification reaction is performed at 150 to 215 ° C. for 3 hours. went. 5% by weight of PTMG having a number average molecular weight of 1000 is added to the polyester having butylene terephthalate as the main repeating unit finally obtained during the transesterification reaction. 48 ppm of water salt (magnesium metal with respect to the amount of polymer) is added by dissolving in 1,4-butanediol, and the final amount of polymer obtained is a hindered phenolic antioxidant [Ciba Geigy Irganox 1010: 0.06% by weight of tetrakis [methylene-3 (3,5-ditert-butyl-4-hydroxy-phenyl) propionate] methane], thioether antioxidant [Cipro Kasei Co., Ltd.] Manufactured by Seenox 412S: (pentaerythritol-tetrakis (β-lauryl Opropionate))) and 0.2% release agent Microcrystalline Wax (manufactured by Nippon Seiwa Co., Ltd., HNP-0190) to 0.3% by weight, followed by 25 ppm tetrabutyl titanate ( The polycondensation reaction was carried out by adding (as a titanium metal to the polymer amount).
[0032]
In the polycondensation reaction, the pressure is gradually reduced from normal pressure to 0.399 Kpa over 85 minutes, the temperature is raised to 240 ° C., and the polycondensation reaction is continued at that temperature for 3 hours and 21 minutes at 0.399 Kpa. A butylene terephthalate copolymer composition was produced. The intrinsic viscosity of the obtained polybutylene terephthalate copolymer composition was 0.847.
[0033]
Next, the polybutylene terephthalate copolymer composition pellets were subjected to solid phase polymerization at 200 ° C. under reduced pressure (0.133 Kpa or less) to obtain a polybutylene terephthalate copolymer composition having an intrinsic viscosity of 1.04. . Table 1 shows the Izod impact strength, heat aging resistance (color tone change ΔE), bleed-out property, and flexural modulus of the resulting polybutylene terephthalate copolymer composition.
[0034]
Example 2
In Example 1, except that the addition amount of the hindered phenol antioxidant (Ciba Geigy Co., Ltd., Irganox 1010) was changed to 0.12% by weight, and the polycondensation reaction time was changed to 3 hours 24 minutes, Reaction was carried out in the same manner as in Example 1 to obtain a polybutylene terephthalate copolymer composition pellet having an intrinsic viscosity of 0.853. Next, the pellet was subjected to solid phase polymerization in the same manner as in Example 1 to obtain a polybutylene terephthalate copolymer composition having an intrinsic viscosity of 1.04. Table 1 shows the Izod impact strength, heat aging resistance (color tone change ΔE), bleed-out property, and flexural modulus of the resulting polybutylene terephthalate copolymer composition.
[0035]
Example 3
In Example 1, except that the amount of hindered phenolic antioxidant [Irganox 1010, manufactured by Ciba-Geigy Co., Ltd.] was changed to 0.2% by weight, and the polycondensation reaction time was changed to 3 hours 24 minutes, Reaction was carried out in the same manner as in Example 1 to obtain polybutylene terephthalate copolymer composition pellets having an intrinsic viscosity of 0.843.
[0036]
Next, the pellet was subjected to solid phase polymerization in the same manner as in Example 1 to obtain a polybutylene terephthalate copolymer composition having an intrinsic viscosity of 1.04. Table 1 shows the Izod impact strength, heat aging resistance (color tone change ΔE), bleed-out property, and flexural modulus of the resulting polybutylene terephthalate copolymer composition.
Comparative Example 1
In Example 1, the amount of tetrabutyl titanate added before entering the transesterification reaction is changed to 58 ppm (based on the amount of polymer as titanium metal), and hypophosphorous acid is substituted for magnesium added 15 minutes before the end of the transesterification reaction. Add 100 ppm of sodium acid dihydrate (as a compound with respect to the amount of polymer) and the amount of tetrabutyl titanate added before entering the polycondensation reaction to 35 ppm (with respect to the amount of polymer as titanium metal) Instead, the reaction was conducted in the same manner as in Example 1 except that the polycondensation reaction temperature was changed to 245 ° C. and the polycondensation reaction time was changed to 3 hours and 14 minutes. A coalescence composition pellet was obtained.
[0037]
Next, the pellet was subjected to solid phase polymerization in the same manner as in Example 1 to obtain a polybutylene terephthalate copolymer composition having an intrinsic viscosity of 1.04. Table 1 shows the heat aging resistance (color tone change ΔE) and bleed-out property of the resulting polybutylene terephthalate copolymer composition.
Comparative Example 2
In Example 1, the amount of tetrabutyl titanate added before entering the transesterification reaction was changed to 58 ppm (relative to the amount of polymer as titanium metal), and the amount of tetrabutyl titanate added before entering the polycondensation reaction was changed to 35 ppm. In place of (as titanium metal relative to the amount of polymer), thioether antioxidant (Sipro Kasei Co., Ltd., Seenox 412S) should not be added, and the polycondensation reaction temperature is 238 ° C. and the polycondensation reaction time is increased. The reaction was carried out in the same manner as in Example 1 except that the time was changed to 3 hours and 25 minutes to obtain a polybutylene terephthalate copolymer composition pellet having an intrinsic viscosity of 0.844.
[0038]
Next, the pellet was subjected to solid phase polymerization in the same manner as in Example 1 to obtain a polybutylene terephthalate copolymer composition having an intrinsic viscosity of 1.04. Table 1 shows the heat aging resistance (color tone change ΔE) and bleed-out property of the resulting polybutylene terephthalate copolymer composition.
Comparative Example 3
In Example 1, the amount of hindered phenolic antioxidant [Irganox 1010, manufactured by Ciba-Geigy Co., Ltd.] was changed to 0.12% by weight, and a thioether antioxidant (Sipro Kasei Co., Ltd., Seenox 412S) was added. The reaction was carried out in the same manner as in Example 1 except that the addition amount was changed to 0.1% by weight and the polycondensation reaction time was changed to 3 hours and 25 minutes. A terephthalate copolymer composition pellet was obtained.
[0039]
Next, the pellet was subjected to solid phase polymerization in the same manner as in Example 1 to obtain a polybutylene terephthalate copolymer composition having an intrinsic viscosity of 1.04. Table 1 shows the heat aging resistance (color tone change ΔE) and bleed-out property of the resulting polybutylene terephthalate copolymer composition.
Comparative Example 4
In Example 1, PTMG having a number average molecular weight of 1000 was replaced with 7% by weight, hindered phenol antioxidant (Irganox 1010 manufactured by Ciba Geigy Co., Ltd.) was 0.42% by weight, and thioether antioxidant. [Cipro Kasei Co., Ltd., Seenox 412S) was replaced with 0.42% by weight, and the polycondensation reaction time was changed to 3 hours and 35 minutes. 0.829 polybutylene terephthalate copolymer composition pellets were obtained.
[0040]
Next, the pellet was subjected to solid phase polymerization in the same manner as in Example 1 to obtain a polybutylene terephthalate copolymer composition having an intrinsic viscosity of 1.04. Table 1 shows the heat aging resistance (color tone change ΔE) and bleed-out property of the resulting polybutylene terephthalate copolymer composition.
Comparative Example 5
In Example 1, except that the hindered phenol antioxidant, the thioether antioxidant and the mold release agent microcrystalline wax were not added, and the polycondensation reaction time was changed to 3 hours and 26 minutes, Example 1 The reaction was conducted in the same manner as above to obtain polybutylene terephthalate copolymer pellets having an intrinsic viscosity of 0.859. Next, the pellet was subjected to solid phase polymerization in the same manner as in Example 1 to obtain a polybutylene terephthalate copolymer having an intrinsic viscosity of 1.04.
[0041]
With respect to the obtained polybutylene terephthalate copolymer, 0.3% by weight of a hindered phenol-based antioxidant [manufactured by Ciba Geigy Co., Ltd., Irganox 1010] and 0.3% of a thioether-based antioxidant [Seenox 412S] Compound% pellets were obtained by adding 0.3% by weight of a weight% release agent and microcrystalline wax [HNP-0190] and kneading with a twin-screw kneader. Table 1 shows the Izod impact strength, heat aging resistance (color change ΔE), bleed-out property, and bending elastic modulus of the obtained pellets.
[0042]
[Table 1]

[0043]
[Table 2]

From Table 1, it can be seen that the copolymer compositions obtained by Examples are excellent in heat aging resistance (color tone change ΔE). Further, according to the production method of Comparative Example 1, it can be seen that the heat aging resistance (color tone change ΔE) is inferior, and the polymerizability is poor even when the polycondensation reaction temperature is high. Furthermore, the compound of the two types of antioxidants of Comparative Example 5 is inferior in heat aging resistance (color change ΔE) in spite of a large amount of antioxidant, bleed-out occurs, and heat of kneading. It can be seen that the Izod impact strength decreases due to the deterioration.
[0044]
【The invention's effect】
According to the production method of the present invention, a polybutylene terephthalate copolymer composition can be produced without performing a post-process and without deteriorating the polymerizability even when an antioxidant is present. Further, the obtained polybutylene terephthalate copolymer composition is excellent in impact resistance, fluidity, and heat aging resistance (color change ΔE) of less than 7 as compared with homopolybutylene terephthalate. Furthermore, it is an excellent copolymer composition free from antioxidant bleed-out.

Claims (4)

A glycol component containing 1,4-butanediol as a main component and a polytetramethylene ether glycol having a number average molecular weight of 650 to 2000 as a copolymerization component and a lower alkyl ester component of a bifunctional carboxylic acid containing dimethylterephthalic acid as a main component , Polytetramethylene ether glycol having a number average molecular weight of 650 to 2000 when a titanium compound and a magnesium compound are present as a polymerization catalyst and a thioether antioxidant and a hindered phenol antioxidant are reacted. (A) is 3 wt% or more and 7 wt% or less, and the amount (B) of the thioether antioxidant and the amount (C) of the hindered phenol antioxidant are 0.01 wt% or more and 0.005 wt%, respectively. 5% by weight or less, and the relationship among A, B, and C satisfies Equation 1. Is allowed, method for producing a polybutylene terephthalate copolymer composition characterized by reacting.

2. The polybutylene terephthalate copolymer composition according to claim 1, wherein a ratio of the titanium compound and the magnesium compound as a polymerization catalyst is 0.5 to 2.0 mol times as magnesium with respect to titanium of the titanium compound. Manufacturing method. The method for producing a polybutylene terephthalate copolymer composition according to claim 1 or 2, which reacts at a temperature of less than 245 ° C. A polybutylene terephthalate copolymer composition, which is a copolymer composition obtained by the production method according to claim 1 or 3 and has a heat aging resistance ΔE of less than 7.