JPH08176418A - Polybutylene terephthalate resin composition - Google Patents

Abstract

PURPOSE: To obtain a polybutylene terephthalate resin compsn. which has a good color tone, does not undergo the degradation in physical properties, e.g. mechanical properties, even under severe conditions including high temp. esp. in the presence of water or moisture, and is excellent in hydrolysis resistance. CONSTITUTION: This compsn. is prepd. by compounding 100 pts.wt. polybutylene terephthalate resin having an intrinsic viscosity of 0.60-1.5dl/g and produced by using titanium potassium oxalate as the catalyst with 0.01-10 pts.wt. carbodiimide compd.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polybutylene terephthalate resin composition. The polybutylene terephthalate-based resin composition of the present invention has a good color tone and is extremely excellent in hydrolysis resistance. Therefore, for example, connectors such as a wire harness connector of an automobile, a material such as a flyback transformer for supplying a high voltage to a cathode ray tube. Is useful as

[0002]

2. Description of the Related Art Polybutylene terephthalate resin (hereinafter sometimes referred to as "PBT resin") has excellent heat resistance, mechanical properties, solvent resistance, electrical properties,
It is widely used as a material for electric parts, electronic parts, automobile parts, machine parts, etc. by making use of its properties such as moldability. However, conventional PBT resins have low hydrolysis resistance, and when used for a long period of time at high temperatures, especially in the presence of water and moisture, their mechanical performance remarkably deteriorates and eventually they become unusable. There was a problem. So P
Several proposals have been made to improve the hydrolysis resistance of BT resins. For example, a method of adding a carbodiimide compound during or after the polycondensation reaction for producing a PBT resin (Japanese Patent Publication No. 38-1520).
JP-B-38-23311 and JP-A-52-58
794), a method of adding a release agent or the like to a PBT resin produced using potassium titanium oxalate as a catalyst (JP-A-6-128464 and JP-A-6-128464).
No. 145479).

[0003]

When the present inventors examined the performance of the PBT resin composition obtained by the above method, the hydrolysis resistance was improved as compared with the conventional PBT resin. However, it turned out that the degree is not always sufficient. Therefore, the object of the present invention is that the color tone is good,
An object of the present invention is to provide a PBT resin composition having extremely excellent hydrolysis resistance.

[0004]

According to the present invention, the above object is to provide a polybutylene terephthalate resin 100 having an intrinsic viscosity of 0.60 to 1.50 dl / g, which is produced by using potassium titanium oxalate as a catalyst. This can be achieved by providing a polybutylene terephthalate resin composition in which 0.01 to 10 parts by weight of a carbodiimide compound is added to parts by weight.

In the PBT resin according to the present invention, 70 mol% or more of the dicarboxylic acid units constituting the PBT resin are terephthalic acid units, and 70 mol% or more of the diol units are 1,4-butanediol units. preferable. The terephthalic acid unit is derived from terephthalic acid or an ester-forming derivative thereof, and examples of the ester-forming derivative include a dialkyl ester of terephthalic acid such as dimethyl terephthalate and a diaryl ester of terephthalic acid such as diphenyl terephthalate. .

The dicarboxylic acid unit other than the terephthalic acid unit and the diol unit other than the 1,4-butanediol unit are 3 units of the dicarboxylic acid unit or the diol unit, respectively.
It is preferably 0 mol% or less. Examples of the acid component that induces the dicarboxylic acid unit include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, and diphenyldicarboxylic acid; adipic acid, sebacic acid,
Examples thereof include aliphatic dicarboxylic acids such as azelaic acid, succinic acid, and oxalic acid; hydroxycarboxylic acids such as β-hydroxyethoxybenzoic acid and p-hydroxybenzoic acid; and ester-forming derivatives thereof. 1,4
-As the diol component for deriving a diol unit other than the butanediol unit, ethylene glycol, propylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol,
1,6-hexanediol, 1,9-nonanediol,
Aliphatic diols having 2 to 10 carbon atoms such as 2-methyl-1,8-octanediol and decamethylene glycol; alicyclic diols such as cyclohexanediol and cyclohexanedimethanol; aromatic diols such as bisphenol A and bisphenol S; Examples thereof include polyalkylene glycols such as polyethylene glycol, polytrimethylene glycol and polytetramethylene glycol. These may be used alone or in combination of two or more.

The PBT resin in the present invention is polycondensed by an esterification reaction or a transesterification reaction between an acid component mainly containing terephthalic acid or its ester-forming derivative and a diol component mainly containing 1,4-butanediol. It is necessary to use potassium titanium oxalate as a polymerization catalyst at that time. The potassium titanium oxalate as used herein means that the carboxyl group of oxalic acid forms a salt with a titanium atom and a potassium atom, and titanium atom and potassium atom are 0.5 and 0.5 mol, respectively, per mol of oxalic acid. Moles and K ₂ TiO (C ₂ O ₄ ) ₂
It is represented by the chemical formula of nH ₂ O. Potassium titanium oxalate can be obtained, for example, by reacting fully hydrolyzed potassium titanate with oxalic acid. The amount of potassium titanium oxalate used is in the range of 10 to 2000 ppm with respect to the total amount of the acid component and the diol component to be polycondensed, from the viewpoint of reducing the polycondensation reaction rate and suppressing the coloration and the viscosity reduction due to the decomposition reaction. Is preferred and 200
The range of up to 1000 ppm is more preferable.

The intrinsic viscosity of the PBT resin in the present invention is in the range of 0.60 to 1.50 dl / g,
It is preferably within the range of 80 to 1.2 dl / g. If the intrinsic viscosity is less than 0.60 dl / g, the mechanical properties of the molded product obtained from the PBT resin composition will be insufficient, while
When it exceeds 1.50 dl / g, the melt viscosity becomes too high, resulting in poor moldability. The intrinsic viscosity mentioned here is a value measured at 30 ° C. in an equal weight mixed solvent of phenol and tetrachloroethane.

The carbodiimide compound in the present invention has the following general formula (I)

Embedded image (In the formula, R ¹ and R ² each represent a hydrocarbon group.)
It is preferable to use a condensate of carbodiimide and diisocyanate represented by (hereinafter, may be abbreviated as polycarbodiimide). In the general formula (I), the hydrocarbon group represented by R ¹ and R ² is
Alkyl groups such as methyl group, ethyl group, isopropyl group, butyl group and octyl group, cycloalkyl groups such as cyclohexyl group, phenyl group, 2-methylphenyl group, 2,6
-Aryl groups such as a diethylphenyl group, a 2,6-diisopropylphenyl group, and a 2,4,6-triisopropylphenyl group. Examples of the carbodiimide represented by the general formula (I) include 2,2′-dimethyldiphenylcarbodiimide, 2,6,2 ′, 6′-tetraethyldiphenylcarbodiimide, 2,6,2 ′, 6′-tetraisopropyldiphenylcarbodiimide, 2, 4, 6,
2 ', 4', 6'-hexaisopropyl diphenyl carbodiimide etc. are illustrated. Further, as polycarbodiimide, 1,3-diisopropylbenzene-2,4-
Examples thereof include a condensate of diisocyanate and a condensate of 1,3,5-triisopropylbenzene-2,4-diisocyanate (hereinafter, this may be abbreviated as triisopropylbenzene polycarbodiimide). These carbodiimide compounds may be used alone or in combination of two or more kinds.

The amount of the carbodiimide compound used in the present invention is 0.01 to 100 parts by weight of the PBT resin.
It is necessary to be 10 parts by weight, and it is preferable to be in the range of 0.1 to 5 parts by weight. When the amount is less than 0.01 part by weight, the hydrolysis resistance of the PBT-based resin composition obtained is not sufficient, while when it exceeds 10 parts by weight, the obtained PBT-based resin composition is colored. Happens.

There is no particular limitation on the time of blending the above-mentioned carbodiimide compound, and it may be at any time during the polycondensation reaction, after the polycondensation reaction, at the time of compounding, molding or the like.

The PBT resin composition of the present invention contains other organic polymers, if necessary, conventionally known additives such as fillers, flame retardants, mold release agents, antioxidants, colorants, plasticizers, It may contain a stabilizer, an ultraviolet absorber, an antistatic agent and the like. In particular, the use of a release agent and / or an antioxidant is desirable because the mechanical properties and chemical properties of the molded product obtained from the PBT resin composition of the present invention are further improved.

The PBT resin composition of the present invention can be molded by using a molding method and a molding apparatus generally used for PBT resins. For example, the PB of the present invention
The T-based resin composition is used for injection molding, extrusion molding, press molding,
Blow molding, extrusion blow molding, injection blow molding, calender molding, cast molding, cast molding and the like can be used to obtain a molded product having any shape and size. The obtained molded product is used for various applications such as electric parts, electronic parts, machine parts, automobile parts, pipes, sheets, films, daily necessities and the like.

The molded article obtained from the PBT resin composition of the present invention is particularly suitable for applications that are often used for a long period of time in a harsh atmosphere accompanied by high temperatures, especially in the presence of moisture and moisture. Even when it is used for a long period of time in such a harsh atmosphere, its high hydrolysis resistance can be exhibited, and deterioration of physical properties such as mechanical properties can be minimized.

[0015]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited thereto. In addition, a part represents a weight part in an Example. The physical properties of the PBT resin and the PBT resin composition were measured by the following methods. (1) Measurement of Tensile Strength According to JIS K7113, the tensile strength of the produced test piece was measured by an autograph (Shimadzu Corporation AG-50).
00B type). (2) Evaluation of hydrolysis resistance The produced test piece was left in a high-speed accelerated life test apparatus (“HASTSYSTEM” manufactured by Davai Espec Corporation) at 121 ° C. for 40 hours under a steam atmosphere of 2 atm, and then taken out from the apparatus. The tensile strength was measured by the above method (1). (3) Color tone (yellowness: b value) of PBT resin composition A pellet of the PBT resin composition having a diameter of 2 mm and a length of 3 mm is used as a sample, and a color computer (SM color computer manufactured by Suga Test Instruments Co., Ltd. SM- The measurement was carried out by the reflection method according to the type 3).

Example 1 100 parts of dimethyl terephthalate, 60 parts of 1,4-butanediol and potassium titanium oxalate (K ₂ Ti (C ₂ O ₄ ) ₂ .2H ₂ O manufactured by Kanto Chemical Co., Inc .: 1 mol of oxalic acid) In contrast, 0.5 mol of titanium atom and 1 mol of potassium atom
0.04 part (bonded at a molar ratio) was charged into a reaction vessel, and the transesterification reaction was carried out while gradually raising the temperature from 145 ° C. to 230 ° C. under normal pressure. When 30 parts of methanol is distilled off, the transesterification reaction is completed, and 240 to 2 under reduced pressure.
A polycondensation reaction was performed by heating at 60 ° C. for 1 hour to obtain a PBT resin having an intrinsic viscosity of 0.95 dl / g. The obtained PB
100 parts of T-based resin and a hindered phenolic antioxidant (“Irganox 1010” manufactured by Ciba-Geigy).
1 part, phosphorus-based antioxidant (Ciba Geigy "Irgafos 168") 0.1 part, montanic acid ester partially saponified wax (Hoechst "Wax OP": mold release agent)
0.3 part and 1.0 part by weight of 2,6,2 ', 6'-tetraisopropyldiphenylcarbodiimide ("Starvacol I" manufactured by Bayer Co., Ltd.) were supplied to a φ44 twin-screw extruder (manufactured by Japan Steel Works, Ltd.). Melted and kneaded at 250 ° C, then cut under water cooling to obtain a PB with a diameter of 2 mm and a length of 3 mm.
Pellets of the T-based resin composition were obtained. Using this pellet as a material, a test piece for a physical property test was molded by an 80-ton injection molding machine manufactured by Nissei Plastic Co., Ltd. The test results of the color tone of the obtained pellets and the hydrolysis resistance of the test pieces are shown in Table 1.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the carbodiimide compound was not used to obtain pellets and test pieces of the PBT resin composition. Table 1 shows the test results of the color tone of the obtained pellets and the hydrolysis resistance of the test pieces.
It was shown to.

Examples 2 to 3 and Comparative Examples 2 to 3 Examples except that the amount of 2,6,2 ', 6'-tetraisopropyldiphenylcarbodiimide used in Example 1 was changed as shown in Table 1. Perform the same operation as 1.
PBT-based resin composition pellets and test pieces were obtained. The test results of the color tone of the obtained pellets and the hydrolysis resistance of the test pieces are shown in Table 1. When 15 parts by weight of 2,6,2 ', 6'-tetraisopropyldiphenylcarbodiimide was blended (Comparative Example 3), the obtained pellets and test pieces were both strongly colored yellowish brown.

Example 4 Example 4 was repeated except that triisopropylbenzene polycarbodiimide (“Stavaxol P-100” manufactured by Bayer Co., Ltd.) was used in place of 2,6,2 ′, 6′-tetraisopropyldiphenylcarbodiimide. Example 1
The same operation as above was performed to obtain pellets and test pieces of the PBT resin composition. The test results of the color tone of the obtained pellets and the hydrolysis resistance of the test pieces are shown in Table 1.

Example 5 PBT was carried out in the same manner as in Example 1 except that the hindered phenol antioxidant, phosphorus antioxidant and montanic acid ester partially saponified wax were not used. Pellets of the resin composition and test pieces were obtained. The test results of the color tone of the obtained pellets and the hydrolysis resistance of the test pieces are shown in Table 1.

Example 6 100 parts of dimethyl terephthalate, 60 parts of 1,4-butanediol and potassium potassium oxalate (K ₂ Ti (C ₂ O ₄ ) ₂ .2H ₂ O manufactured by Kanto Chemical Co., Inc .: as described above).
0.04 part was charged into a reaction vessel, and the transesterification reaction was carried out while gradually raising the temperature from 145 ° C to 230 ° C under normal pressure. The transesterification reaction was terminated when 30 parts of methanol was distilled off, and the polycondensation reaction was carried out by heating at 240 to 260 ° C. for 1 hour under reduced pressure. After completion of the reaction, 2, 6, 2 ',
0.113 parts by weight of 6'-tetraisopropyldiphenylcarbodiimide ("Stavaxol I" manufactured by Bayer Co., Ltd.) was added to a polycondensation reaction vessel, and the mixture was kneaded under normal pressure for 10 minutes to obtain a PBT resin having an intrinsic viscosity of 0.95 dl / g. Got
100 parts of the obtained PBT resin and a hindered phenolic antioxidant (“Irganox 10 manufactured by Ciba Geigy”)
10 "), 0.1 part of a phosphorus-based antioxidant (" Irgafos 168 "manufactured by Ciba-Geigy) and 0.3 part of montanic acid ester partially saponified wax (" Wax OP ": release agent manufactured by Hoechst). Part is supplied to a φ44 twin-screw extruder (manufactured by Japan Steel Works Ltd.), melt-kneaded at 250 ° C., and then cut under water cooling to obtain a PBT having a diameter of 2 mm and a length of 3 mm.
A pellet of the resin composition was obtained. Using this pellet as a material, a test piece for a physical property test was molded by an 80-ton injection molding machine manufactured by Nissei Plastic Co., Ltd. The test results of the color tone of the obtained pellets and the hydrolysis resistance of the test pieces are shown in Table 1.

Comparative Example 4 The procedure of Example 1 was repeated except that 0.04 part of tetraisopropyl titanate was used in place of 0.04 part of potassium titanium oxalate, and a PBT resin composition was prepared. Pellets and test pieces were obtained. The test results of the color tone of the obtained pellets and the hydrolysis resistance of the test pieces are shown in Table 1.

Comparative Example 5 The same operation as in Example 1 except that 0.04 part of tetraisopropyl titanate was used in place of 0.04 part of potassium titanium oxalate and no carbodiimide compound was used. Then, pellets and test pieces of the PBT resin composition were obtained. The test results of the color tone of the obtained pellets and the hydrolysis resistance of the test pieces are shown in Table 1.

[Table 1]

[0024]

According to the present invention, there is provided a polybutylene terephthalate resin composition which has a good color tone and is extremely excellent in hydrolysis resistance. INDUSTRIAL APPLICABILITY The polybutylene terephthalate resin composition of the present invention can provide a molded product capable of stably maintaining good mechanical performance even when exposed to moisture or moisture at high temperature for a long time.

Claims (1)

[Claims] 1. 0.01 to 10 parts by weight of a carbodiimide compound is added to 100 parts by weight of a polybutylene terephthalate resin having an intrinsic viscosity of 0.60 to 1.50 dl / g, which is produced by using potassium titanium oxalate as a catalyst. A polybutylene terephthalate resin composition comprising: