JP2006104361A - Polyester resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester resin composition which excels in injection molding high cycling properties and has dimensional properties for continuous use of a mold, hydrolysis resistance of a necessary property as a connector, and good toughness. <P>SOLUTION: The polyester resin composition comprises (A) 100 pts. wt. polybutylene terephthalate resin having a Ti content of 30-110 ppm in terms of weight which is obtained by continuously subjecting a dicarboxylic acid component having terephthalic acid as the main component and a diol having 1,4-butanediol as the main component to esterification reaction in one or a plurality of esterification reaction vessels and then conducting continuous polycondensation reaction, (B) 0.0001-0.01 pt. wt. nucleating agent, (C) 0.05-1.0 pt. wt. phosphite compound having only one group represented by formula 1 in the molecule and all groups adjacent to O of aromatic groups, and (D) 0.05-3.0 pts. wt. release agent, and has a cooling down crystallization temperature of 190-196°C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyester resin composition used in the manufacture of a connector for connecting electrical and electronic equipment circuits having excellent injection molding high cycle properties and hydrolysis resistance.

  Polybutylene terephthalate (hereinafter abbreviated as PBT) is excellent in mechanical properties, heat resistance, chemical resistance, weather resistance, and electrical properties, and is therefore used in a wide range of fields such as automobiles and electrical / electronic parts. In particular, the use of connectors for connecting electrical and electronic equipment circuits is excellent in injection moldability and dimensional stability. However, in recent years, shortening of the injection molding cycle (hereinafter referred to as “high cycle performance”) is required for the purpose of improving productivity, and PBT excellent in this high cycle performance is demanded.

In order to meet such a demand, Patent Document 1 proposes a composition in which a release agent and an antioxidant are blended with a PBT resin. Patent Document 2 proposes a method of blending two kinds of PBTs that define the amount of carboxyl end groups, the temperature-falling crystallization temperature, and the amount of residual tetrahydrofuran.
Japanese Patent Laid-Open No. 01-103654 JP 2004143321 A

  However, when the PBT resin composition described in Patent Document 1 is used, the injection molding high cycle property is not sufficient because the crystallization rate is low. Furthermore, in order to improve the high cycle property of injection molding, it is necessary to improve the crystallization speed of the PBT resin composition. When the crystallization speed of the PBT resin composition is improved, the dimensional characteristic represented by the molding shrinkage ratio is changed. Therefore, using the conventional PBT resin composition as described in Patent Document 1, the same size as the conventional one is used. When the mold is continuously used, the dimensions of the molded product as a connector product change. Therefore, in order to carry out continuous use of the mold, it is essential that the injection molding high cycle property is excellent and that the PBT resin composition also has the same dimensional characteristics as those in the past. Further, when the PBT resin composition described in Patent Document 2 is used, the injection molding high cycle property is not satisfactory.

The present invention has been obtained as a result of intensive studies by the present inventors in order to solve the above problems. That is, the present invention
(1) A dicarboxylic acid component containing terephthalic acid as a main component and a diol containing 1,4 butanediol as a main component are continuously subjected to esterification in one or a plurality of esterification reaction tanks, and then continuously. 100 parts by weight of polybutylene terephthalate resin (A) having a Ti content of 30 to 110 ppm in terms of weight, 0.0001 to 0.01 parts by weight of crystal nucleating agent (B), and the following formula A phosphite compound (C) having only one group represented by 1 in the molecule and all groups adjacent to O being aromatic, 0.05 to 1.0 parts by weight, release agent (D) 0 A polyester resin composition comprising 0.05 to 3.0 parts by weight and having a cooling crystallization temperature of 190 to 196 ° C.,

(2) The polyester resin composition according to (1), which has a molding shrinkage ratio of 0.8% to 1.2% with respect to a mold dimension perpendicular to the resin flow direction.
(3) A phosphite compound (C) having only one group represented by formula 1 in the molecule, and all groups adjacent to O being aromatic is tris (2,4-di-t-butylphenyl). The polyester resin composition according to (1) or (2), which is a phosphite,
(4) The polyester resin composition according to any one of (1) to (3), wherein the crystal nucleating agent (B) is talc.
(5) The polyester resin composition according to any one of (1) to (4), wherein the release agent (D) is a montanic acid partially saponified ester wax,
It is.

  As described above, the present invention provides a polyester resin composition having excellent injection molding high cycle properties, dimensional characteristics for continuous use of a mold, and hydrolysis resistance and toughness which are necessary characteristics as a connector. be able to.

  Hereinafter, the present invention will be described in detail.

  The polybutylene terephthalate resin (A) having a Ti content of 30 to 110 ppm constituting the present invention is a high molecular weight having an ester bond in the main chain using terephthalic acid as an acid component and 1,4 butanediol as a diol component. The thermoplastic polyester. Further, the PBT constituting the present invention continuously performs esterification reaction in one or more esterification reaction tanks with a dicarboxylic acid component mainly composed of terephthalic acid and a diol mainly composed of 1,4 butanediol. And then obtained by continuous polycondensation reaction. By using PBT produced by the continuous polymerization method, the mechanism is not clear, but it is possible to improve the high cycle property of injection molding. The continuous polymerization method is not particularly limited except that one or a plurality of reaction tanks are used in the esterification reaction tank, but it is preferable to perform continuous polymerization using a series continuous tank reactor. Specifically, a raw material mainly composed of a diol component and a dicarboxylic acid component is prepared as a slurry, the slurry is supplied to a first esterification reaction tank, and the esterification reaction is performed in one or more esterification reaction tanks. The oligomer which is the esterification reaction product obtained can be subjected to a polycondensation reaction through one or more preliminary polycondensation reaction tanks and a final polymerization machine. The obtained polybutylene terephthalate is extracted in the form of a strand from the bottom of the final polymerization machine through a die and is cooled with cooling water or cut with a pelletizer while cooling with cooling water to form pellets or other granular materials It is preferable.

  Although it does not specifically limit as a model of the esterification reaction tank used for manufacture of PBT of this invention, For example, a vertical stirring complete mixing tank, a vertical thermal convection mixing tank, a shelf type reaction tank, etc. are used. When a plurality of reaction vessels are used, a plurality of vessels of the same or different types can be used in series.

  In the continuous polymerization method of PBT, the presence of a catalyst particularly in the esterification step is indispensable, and an organic titanium catalyst is most commonly used as the catalyst. Specifically, the organic titanium compound used in the present invention includes titanic acid methyl ester, tetra-n-propyl ester, tetraisopropyl ester, tetra-n-butyl ester, tetraisobutyl ester, tetra-tert-butyl ester, tetra- Examples include 2-ethylhexyl ester, tetraoctyl ester, phenyl ester, benzyl ester, tolyl ester, and mixed esters thereof. Among these, tetra-n-propyl ester (tetra-n-propyl titanate), tetraisopropyl ester (tetra-isopropyl titanate), and tetra-n-butyl ester (tetra-n-butyl titanate) of titanic acid are available at low cost. The tetra-n-butyl ester of titanic acid (tetra-n-butyl titanate) is particularly preferably used. These organic titanium compounds may use only 1 type and can use 2 or more types together. Further, the same species may be used during the esterification reaction and polycondensation, or different organic titanium compounds may be used. Further, this organic titanium compound may be added together with a suitable organic solvent. Examples of the organic solvent in this case include isopropanol, n-butanol, isobutanol, ethylene glycol, propylene glycol, and 1,4-butanediol. In consideration of the influence on quality, etc., 1,4-butanediol is preferable. Used.

  Although there is no restriction | limiting in particular as an addition method of an esterification catalyst, Specifically, the method of supplying directly to a 1st esterification reaction tank, the method of adjusting simultaneously when making a slurry, 1st esterification reaction of raw material slurry The method of supplying with a metering pump to the line which supplies to a tank is mentioned. Further, in the present invention, an organic titanium catalyst can be additionally added. Although there is no particular limitation, when there are a prepolymerization tank or a plurality of prepolymerization tanks, piping between the prepolymerization tanks, between the prepolymerization tank and the final polymerization machine Additional additions can be made to the piping.

  In the present invention, it is essential that the total amount of the organic titanium compound used as the polymerization catalyst is 30 to 110 ppm, preferably 30 to 49 ppm, based on the total weight of the polymer in terms of Ti atoms. In the present invention, the Ti content is a value obtained by quantifying the Ti content using ICP emission spectroscopic analysis after ashing after adding sulfuric acid to the sample and thermally decomposing. If this Ti content is 30 ppm or less, the polymerization rate will be slow, leading to deterioration of productivity. If it exceeds 110 ppm, the thermal decomposition rate in the polymerization process will be accelerated, the carboxyl group terminal will increase, and the high cycle property It also has an adverse effect. Furthermore, when it is in the range of 30 to 49 ppm, a sufficient polymerization rate can be obtained, and polybutylene terephthalate having excellent high cycle properties can be obtained.

  The polybutylene terephthalate used in the present invention preferably has an intrinsic viscosity of 0.36 to 1.60, particularly 0.52 to 1.25 when an o-chlorophenol solution is measured at 25 ° C. is there. If the intrinsic viscosity is less than 0.36, the mechanical properties are poor. On the other hand, if the intrinsic viscosity exceeds 1.60, the moldability tends to be poor.

    As the crystal nucleating agent (B) constituting the present invention, either an organic substance or an inorganic substance can be used. As the inorganic substance, single substances such as talc, Zn powder, and Al powder, and nitrides such as aluminum nitride, titanium nitride, and boron nitride can be used alone or in admixture of two or more. Organic substances include calcium oxalate, sodium oxalate, calcium benzoate, calcium phthalate, calcium tartrate, magnesium stearate, polyacrylate, polymers such as polyester, polyethylene, polypropylene, and polymers. These can be used alone or in admixture of two or more. Of these, talc is particularly preferable, and among the crystal nucleating agents, the effect of improving the high cycle property is particularly excellent. In addition, it is not possible to obtain excellent high cycle performance by simply adding a crystal nucleating agent to ordinary PBT, and a dicarboxylic acid component mainly composed of terephthalic acid and a diol mainly composed of 1,4 butanediol. Crystallization is performed on polybutylene terephthalate resin (A) having a Ti content of 30 to 110 ppm, which is obtained by continuously performing an esterification reaction in one or a plurality of esterification reaction tanks and then continuously performing a polycondensation reaction. The excellent high cycle property of the present invention can be obtained only by blending the nucleating agent (B).

  The compounding quantity of the crystal nucleating agent (B) in this invention is 0.0001-0.01 weight part. When the blending amount of the crystal nucleating agent (B) is less than 0.0001 part by weight, the temperature drop crystallization temperature of the resin composition is less than 190 ° C., so that the injection molding high cycle property is inferior and exceeds 0.01 part by weight. And a large difference in dimensional characteristics with the conventional general PBT, it is difficult to continue using the mold, and in reality, it is possible to use a polyester resin composition containing a crystal nucleating agent It becomes difficult.

    Further, the phosphite compound (C) used in the present invention has only one group represented by the formula 1 in the molecule, and all the groups adjacent to O are aromatic, whereby the phosphite compound A decrease in hydrolysis resistance, which is a concern when blended with PBT, can be prevented.

Further, this phosphite compound (C) exhibits an effect of reducing an increase in molding shrinkage due to blending of a crystal nucleating agent. This effect is obtained by suppressing the crystallization of PBT and does not adversely affect the high cycle property.

  In the present invention, as the phosphite compound (C) having only one group represented by the formula 1 in the molecule and all the groups adjacent to O being aromatic, tris (2,4-di-t -Butylphenyl) phosphite, tris (mono, dinonylphenyl) phosphite, tris (monononylphenyl) phosphite and the like can be mentioned, and these can be used alone or in combination.

    In particular, the phosphite compound (C) is more effective when it is tris (2,4-di-t-butylphenyl) phosphite. In addition to the effect of reducing the increase in molding shrinkage due to the addition of the crystal nucleating agent, the effect here refers to the effect of suppressing the degradation of hydrolysis resistance of the entire polyester resin composition based on the phosphite compound in particular. Demonstrate. The compounding quantity of the phosphite type compound (C) in this invention is 0.05-1.0 weight part of the whole resin composition. When the blending amount of the phosphite compound (C) is less than 0.05 parts by weight, an increase in molding shrinkage due to blending of a crystal nucleating agent which is the purpose of blending the phosphite compound (C) is reduced. If the effect is not obtained and the amount exceeds 1.0 part by weight, hydrolysis of the phosphite compound may cause a decrease in hydrolysis resistance of the entire polyester resin composition.

  In the present invention, it is essential to use the release agent (D) in order to improve the high cycle property. Release agents include plant waxes such as carnauba wax and rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as montan wax and partially saponified ester wax of montanic acid, paraffin wax, polyethylene wax, etc. Examples thereof include oil-based waxes such as petroleum wax, castor oil and derivatives thereof, fatty acid and derivatives thereof, and montanic acid partially saponified ester wax is particularly preferably used, and the effect of improving the high cycle property among release agents. Excellent. The montanic acid partially saponified ester wax is a kind of fossil wax, and montanic acid obtained by pulverizing and extracting from vegetable oil components obtained from coal is partially esterified with alcohol or dicarboxylic acid, and then the periodic table These are obtained by neutralization with metal oxides or hydroxides such as sodium, potassium, beryllium, magnesium, calcium, lithium and aluminum.

  The compounding quantity of the mold release agent (D) in this invention is 0.05-3.0 weight part. When the blending amount of the release agent (D) is less than 0.05 parts by weight, sufficient release performance is not exhibited, so the high cycle property is inferior, and when it exceeds 3.0 parts by weight, printing on the surface of the molded product is performed. Secondary processing such as bonding becomes difficult, which is not preferable.

  The polyester resin composition of the present invention must have a temperature-falling crystallization temperature of 190 to 196 ° C., and in order to make the temperature-falling crystallization temperature 190 ° C. or higher, it is necessary to add a crystal nucleating agent (B). . Moreover, the temperature-fall crystallization temperature can be made 196 degrees C or less by making the compounding quantity of a crystal nucleating agent (B) 0.01 parts weight or less. In the present invention, the temperature drop crystallization temperature is a value measured with a differential scanning calorimeter at a temperature drop rate of 20 ° C./min.

  When the temperature-falling crystallization temperature of the polyester resin composition is less than 190 ° C., the high cycle property is inferior, and when it exceeds 196 ° C., the toughness is reduced, or a large difference in dimensional characteristics from the general PBT described in Patent Document 1. Therefore, it is difficult to use the mold continuously, and it is practically impossible to use the polyester resin composition.

  Further, the polyester resin composition of the present invention is formed by injection-molding a square plate having a length of 80 mm, a width of 80 mm, and a thickness of 1 mm with a film gate at the upper end under the conditions of a cylinder temperature of 260 ° C. and a mold temperature of 40 ° C. Die dimensions when measuring the width of the part 1mm below the top edge and the width of the part 40mm below the top edge, the width of the part 1mm above the bottom edge with the final filling part as the bottom edge, with the gate of the plate as the top edge It is preferable that the mold shrinkage rate from the mold, that is, the mold shrinkage rate with respect to the mold dimension perpendicular to the resin flow direction, is 0.8% to 1.2%.

    Although there is no restriction | limiting in particular in the molding machine which injection-molds this square plate, It is preferable to use the molding machine whose mold clamping pressure is 40t-80t class. The injection time is 7 to 15 seconds, the cooling time is 8 to 12 seconds, the injection pressure is set to 10 to 20% higher than the lowest injection pressure that can be filled up to the final filling part, and the cylinder temperature is 260 ° C. A square plate is obtained by injection molding at a mold temperature of 40 ° C. The square plate is measured by measuring the dimensions of the width of the portion 1 mm below the upper end and the width of the portion 40 mm below the upper end, the width of the portion 1 mm above the lower end with the final filling portion as the lower end, with the gate of the square plate as the upper end. The mold shrinkage rate is calculated from the mold dimensions.

    If the mold shrinkage is 0.8% or less, it may be difficult to release the mold from the mold, which is not preferable for improving the high cycle property. Therefore, it is difficult to continue to use the mold because the dimensional characteristics are different from those of the PBT, and it is practically impossible to use such a polyester resin composition.

  In the polyester resin composition of the present invention, usual additions such as antioxidants, stabilizers, ultraviolet absorbers, colorants, flame retardants, flame retardant aids, impact modifiers, etc., within a range not impairing the effects of the present invention. Agents and small amounts of other polymers can be added.

  Examples of antioxidants include 2,6-di-t-butyl-4-methylphenol, tetrakis (methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate) methane, tris Phenol compounds such as (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, sulfur such as dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate System compounds and the like.

  Stabilizers include benzotriazole compounds including 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, and benzophenone compounds such as 2,4-dihydroxybenzophenone, mono- or distearyl phosphate, trimethyl phosphate And phosphoric acid esters.

  These various additives may have a synergistic effect by combining two or more kinds, and may be used in combination.

  For example, the additive exemplified as the antioxidant may act as a stabilizer or an ultraviolet absorber. Some of those exemplified as stabilizers also have an antioxidant action and an ultraviolet absorption action. In other words, the classification is for convenience and does not limit the action.

  Examples of the ultraviolet absorber include 2-hydroxy-4-n-dodecyloxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, and bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane. Benzophenone-based ultraviolet absorbers typified by, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) Benzotriazole, 2- (2′-hydroxy-3 ′, 5′-bis (α, α′-dimethylbenzyl) phenylbenzotriazole, 2,2′methylenebis [4- (1,1,3,3-tetramethyl) Butyl) -6- (2H-benzotriazol-2-yl) phenol], methyl-3- [3-tert-butyl-5 The benzotriazole type ultraviolet absorber represented by the condensate with-(2H-benzotriazol-2-yl) -4-hydroxyphenylpropionate-polyethylene glycol can be mentioned.

  Also, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, tetrakis (2,2,6,6- Tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetra Carboxylate, poly {[6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethylpiperidyl ) Imino] hexamethylene [(2,2,6,6-tetramethylpiperidyl) imino]}, polymethylpropyl 3-oxy- [4- (2,2,6,6-tetramethyl) piperidinyl] siloxane. Can also include hindered amine light stabilizers represented by, such light stabilizers in combination with the ultraviolet absorber and various antioxidants, exhibit better performance in terms of weather resistance.

  Flame retardants are halogen-based, phosphoric ester-based, metal salt-based, red phosphorus, silicon-based, metal hydrate-based, and the like, and also include anti-dripping agents. Examples of the colorant include organic dyes, organic pigments, and inorganic pigments. Other examples include fluorescent brighteners, phosphorescent pigments, fluorescent dyes, flow modifiers, inorganic and organic antibacterial agents, photocatalytic antifouling agents, impact modifiers such as graft rubber, infrared absorbers, and photochromic agents. be able to.

  In the polyester resin composition of the present invention, these blending components are preferably dispersed uniformly, and any blending method can be used. A typical example is a method of melt-kneading at a temperature of 200 to 350 ° C. using a known melt mixer such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, or a mixing roll. Each component may be mixed in advance and then melt kneaded. Or about 100 parts by weight of the total amount of (A) to (D), for a small amount of additive component such as 1 part by weight or less, after kneading and pelletizing other components by the above method, etc., It can also be added before molding. In addition, although it is better that the water | moisture content adhering to each component is less and it is desirable to dry beforehand, not all the components need to be dried.

  As an example of a preferable production method, a method is used in which a twin screw extruder having a cylinder temperature of 230 to 300 ° C. is used, and raw materials containing (A) to (D) and other additives are supplied to the extruder and kneaded. Can be mentioned.

  The polyester resin composition of the present invention is generally molded by a known thermoplastic resin molding method such as injection molding, extrusion molding, blow molding, transfer molding, vacuum molding, etc., among which injection molding is preferable. In the case of producing by injection molding, it is preferable that the cylinder temperature is higher by about 20 ° C. to 50 ° C. than the melting point of the resin composition, and the mold temperature is 30 to 90 ° C.

  The polyester resin composition of the present invention is useful as a molding material for a connector for electrical / electronic equipment circuit connection.

Hereinafter, the present invention will be described in more detail with reference to examples.
The evaluation method of an Example and a comparative example is shown next.

(1) Evaluation of Ti content 5 g of sample polymer is pyrolyzed by adding sulfuric acid and then incinerated using an electric furnace at 550 °. Next, the ash content was treated with dilute nitric acid, and the Ti content was quantified using an ICP emission spectroscopic analyzer (Hitachi ICP emission spectrophotometer P-4000 type) with a constant volume of 50 ml.

(2) Evaluation of temperature drop crystallization temperature The sample polymer was heated from 40 ° C. to 250 ° C. at 20 ° C./min with a differential scanning calorimeter (DSC), held at 250 ° C. for 5 minutes, and then cooled at 20 ° C./min. The crystallization temperature (Tc) when the temperature was lowered was measured.

(3) Evaluation of molding shrinkage rate Using PS60DSE made by Nissei Plastic Industry Co., Ltd., injection time 10 seconds, cooling time 10 seconds, injection pressure 10% higher than the minimum injection pressure that can fill the injection pressure to the final filling part And a square plate having a length of 80 mm, a width of 80 mm, and a thickness of 1 mm with a film gate disposed at the upper end is injection-molded under conditions of a cylinder temperature of 260 ° C. and a mold temperature of 40 ° C. to obtain a square plate. The dimensions of the width of the portion 1 mm below the upper end, the width of the portion 40 mm below the upper end, the width of the portion 40 mm below the upper end, and the width of the portion 1 mm above the lower end with the lower end as the lower end are measured. For each of the measured values of the three points, the molding shrinkage from the mold dimensions is calculated using the formula shown below, the average value of the three points is obtained, and measurement is further performed for five square plates. Was the molding shrinkage.
Mold shrinkage rate (%) = <(die size−square plate size) / die size> × 100.

(4) Evaluation of injection molding high cycle property A waterproof connector housing molded product used for connecting electrical and electronic equipment circuits for automobiles was molded under conditions of a cylinder temperature of 260 ° C and a mold temperature of 80 ° C. At that time, the cooling time was shortened every second, and the shortest cooling time during which 100 shots or more could be molded without deformation of the connector was confirmed, which was used as an index of molding high cycle property.

(5) Evaluation of dimensional characteristics The molding shrinkage rate is measured, and the difference from the molding shrinkage rate of Comparative Example 1 which is a conventional PBT inferior in the high cycle property in which no crystal nucleating agent is blended is 0.1% or less. ◎, a value exceeding 0.1% and less than 0.2% was indicated as ◯, and a value exceeding 0.2% was indicated as ×, and used as an index of dimensional characteristics.

(6) Evaluation of hydrolysis resistance An ASTM No. 4 type tensile test piece was molded under the conditions of a cylinder temperature of 280 ° C and a mold temperature of 40 ° C, and used as a sample. The tensile test piece was treated at 121 ° C. in saturated steam for 50 hours, and the tensile strength was measured for the sample before treatment and the sample after treatment according to ASTM D638. The strength retention was determined according to the following formula and used as an index of hydrolysis resistance.
Strength retention (%) = (Tensile strength after treatment / Tensile strength before treatment) × 100.

(7) Evaluation of toughness (tensile elongation)
An ASTM No. 4 type tensile test piece was molded under conditions of a cylinder temperature of 280 ° C. and a mold temperature of 40 ° C., and used as a sample. The tensile test piece was measured in accordance with ASTM D638, the tensile elongation was measured, and used as an indicator of toughness.

The compounding composition used for the Example and the comparative example is shown.
In Examples and Comparative Examples of the present invention, PBT prepared by the following method was used.

Reference example 1
(A-1) PBT-1: Production of intrinsic viscosity 0.86, Ti content 35 ppm Slurry tank, slurry storage tank, 1 esterification reaction tank, 2 prepolymerization tanks, 1 final polymerization machine, pelletizer First, after both raw materials were supplied to the slurrying tank at a ratio of 692 parts by weight of 1,4 butanediol to 754 parts by weight of terephthalic acid, the mixture was stirred and mixed, and the slurry was adjusted. The slurry was transferred to a slurry storage tank at a constant temperature of 50 ° C., and the slurry was supplied from a slurry storage tank to a fully mixed tank type esterification reaction tank having a rectification tower at a constant speed of 1446 parts by weight / hour. A 1,4-butanediol solution of n-butyl titanate (TBT) was continuously fed to the esterification reactor at 4 parts by weight / hour. The amount of TBT supplied to the esterification reaction tank was 35 ppm based on the total weight of the polymer in terms of Ti atoms.
The reaction conditions of this esterification reactor were maintained at a temperature of 230 ° C. and a pressure of 73 kPa, a residence time of 1.8 hr, THF and water were distilled from the top of the rectification column, and 1,4 butanediol was rectified. Refluxed from the tower bottom. At this time, THF distilled from the top of the rectifying column was 68 parts by weight / hour. Further, an oligomer having a reaction rate of 95% of the dicarboxylic acid component was obtained in this esterification reaction tank.
Subsequently, this oligomer was supplied to the first prepolymerization tank of a complete mixing tank type with a gear pump, maintained at a temperature of 245 ° C. and a pressure of 4 kPa, and reacted at a residence time of 1 hr. The reaction rate of the dicarboxylic acid component was 99.2%, An oligomer having an intrinsic viscosity of 0.20 was obtained.
Next, this oligomer was supplied to the second prepolymerization tank of the complete mixing tank type with a gear pump. The second prepolymerization tank was maintained at a temperature of 245 ° C. and a pressure of 3.3 kPa, and reacted at a residence time of 1 hr. 30 oligomers were obtained.
The oligomer was supplied to a final polymerization machine (horizontal biaxial reactor) and reacted at a temperature of 240 ° C. and a pressure of 200 Pa to obtain a polymer. This polymer was discharged in a strand from the system through a die by a gear pump, cooled by cooling water, and pelletized by a pelletizer.

Reference example 2
(A-2) PBT-2: Production method of intrinsic viscosity 0.86, Ti content 80 ppm Except that the addition amount of TBT including the additional addition amount was 80 ppm in terms of Ti atom with respect to the total weight of the polymer (A Adjustment was performed in the same manner as in -1).

Reference example 3
(A-3) PBT-3: Production method with intrinsic viscosity of 0.86 and Ti content of 120 ppm Except that the addition amount of TBT including the additional addition amount was set to 120 ppm with respect to the total weight of the polymer in terms of Ti atoms (A Adjustment was performed in the same manner as in -1).

Reference example 4
(A-4) PBT-4: Production method with intrinsic viscosity of 1.10 and Ti content of 35 ppm Adjusted by the same method as (A-1) except that the polymerization degree in the final polymerization machine was increased by extending the residence time. did.

Furthermore, the following were used for the Example and comparative example of this invention.
(A-5) PBT resin: “Toraycon 1100S” manufactured by Toray Industries, Inc., intrinsic viscosity 0.89, batch polymerized product (B-1) Crystal nucleating agent: Talc (manufactured by Takehara Chemical Industries, Ltd .: Hytron)
(B-2) Crystal nucleating agent: Magnesium stearate (C-1) Phosphite compound: Tris (2,4-di-t-butylphenyl) phosphite
(Asahi Denka Kogyo Co., Ltd .: ADK STAB 2112)
(C-2) Phosphite compound: Tris (monononylphenyl) phosphite
(Asahi Denka Kogyo Co., Ltd .: ADK STAB 1178)
(C-3) Phosphite compound: Tris (mono, dinonylphenyl) phosphite
(Asahi Denka Kogyo Co., Ltd .: ADK STAB 329K)
(C-4) Phosphite compound: 2,2 methylenebis (4,6-di-t-butylphenyl) octyl phosphite (Asahi Denka Kogyo Co., Ltd .: HP-10)
(C-5) Phosphite compound: bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite (Asahi Denka Kogyo Co., Ltd .: PEP36)
(D-1) Release agent: Montanic acid partially saponified ester wax
(Clariant Japan Co., Ltd .: Rico Wax OP)
(D-2) Release agent: Montanate ester wax
(Clariant Japan Co., Ltd. product: Lycowax E).

Examples 1-9
(A) to (D) were blended in combinations shown in Table 1.
The manufacturing method of the material described in each Example is as follows. That is, it was manufactured using a twin screw extruder having a screw diameter of 57 mmφ set at a cylinder temperature of 250 ° C. (A) to (D) and all other additives were supplied from the original storage portion, melt kneaded, and the strand discharged from the die was cooled in a cooling bath, and then pelletized with a strand cutter. Each of the obtained pellets was dried for 3 hours or more with a hot air dryer at 130 ° C., and then molded and evaluated using the method described in the evaluation method. The results are also shown in Table 1. All of the obtained compositions were excellent in injection molding high cycle properties, dimensional characteristics, hydrolysis resistance, and toughness.

Comparative Examples 1-10
Table 2 shows the formulation of the comparative example and the evaluation results.
Except that the composition of the resin composition was changed as shown in Table 2, pelletization and molding were performed in the same manner as in Examples, and various evaluations were performed.
In the phosphite compounds of (C-4) and (C-5), the group represented by Formula 1 is not only one in the molecule, or the group adjacent to O is not only aromatic. It does not correspond to the phosphite compound limited in the present invention.
The obtained composition was inferior in any of injection molding high cycle properties, dimensional characteristics, hydrolysis resistance, and toughness.

Claims (5)

A dicarboxylic acid component mainly composed of terephthalic acid and a diol mainly composed of 1,4 butanediol are continuously subjected to esterification reaction in one or a plurality of esterification reaction tanks, and then continuously polycondensed. With respect to 100 parts by weight of polybutylene terephthalate resin (A) having a Ti content of 30 to 110 ppm in terms of weight obtained by reacting,
0.0001 to 0.01 part by weight of crystal nucleating agent (B),
0.05 to 1.0 parts by weight of a phosphite compound (C) having only one group represented by the following formula 1 in the molecule, and the groups adjacent to O are all aromatic,
Containing 0.05 to 3.0 parts by weight of release agent (D),
A polyester resin composition having a cooling crystallization temperature of 190 to 196 ° C.

The polyester resin composition according to claim 1, wherein a molding shrinkage ratio with respect to a mold dimension perpendicular to the resin flow direction is 0.8% to 1.2%. Tris (2,4-di-t-butylphenyl) phosphite is a phosphite compound (C) having only one group represented by the formula 1 in the molecule, and the groups adjacent to O are all aromatic. The polyester resin composition according to claim 1 or 2. The polyester resin composition according to any one of claims 1 to 3, wherein the crystal nucleating agent (B) is talc. The polyester resin composition according to any one of claims 1 to 4, wherein the release agent (D) is a montanic acid partially saponified ester wax.