KR100530913B1 - Method for producing polybutylene terephthalate resin composition - Google Patents

Abstract

The present invention comprises the step of esterifying dimethyl terephthalate, 1,4-butanediol, a modifier and a reaction catalyst to produce a reactant, and adding a stabilizer to the reactant and condensation polymerization to produce a polymer, or the polymer 60 to It relates to a method of producing a PBT resin composition excellent in impact resistance, characterized in that it further comprises the step of melt-kneading by adding 6phr of antioxidant and lubricant to 95% by weight and 5 to 40% by weight of glass fiber. The PBT resin composition uses an organic titanium compound as a reaction catalyst and a phosphorus compound as a stabilizer. The modifier is preferably 10 to 30% by weight based on the bifunctional carboxylic acid, the reaction catalyst is used from 0.005 to 0.5% by weight with respect to 100% by weight of the polymer, 0.01 to 0.1% by weight is preferred. The stabilizer is used in an amount of 0.005 to 0.5% by weight based on 100% by weight of the polymer, and preferably 0.01 to 0.1% by weight.

Description

Method for producing polybutylene terephthalate resin composition

Field of invention

The present invention relates to a method for producing a polybutylene terephthalate (PBT) resin composition. More specifically, the present invention relates to a method for producing a thermoplastic PBT resin composition having improved impact resistance by adding a modifier in preparing a polymer.

Background of the Invention

In general, PBT is prepared by polycondensation of bis (2-hydroxybutyl) terephthalate obtained by esterification or transesterification of difunctional carboxylic acid and 1,4-butanediol in the presence of a catalyst under a catalyst and a stabilizer. PBT manufactured as described above is widely used for plastic molded products, especially engineering plastics due to its excellent chemical, physical and electrical properties. Particularly, PBT is widely used in precision molded products requiring molding processability because of better fluidity than polyethylene terephthalate, which is polyester-based. Recently, PBT has been widely used in industrial fields such as electric, electronic and automotive parts.

However, since PBT has high crystallinity, the material is vulnerable, so it has a disadvantage of low impact resistance against sudden impact or external stress. In particular, since the impact resistance is further lowered at low temperatures, methods for improving the use of these materials have been widely proposed until now, and most of these methods have been known to improve physical properties by adding various types of impact modifiers during compounding. .

The most widely used method for improving the impact resistance of PBT is a method of adding α-olefin copolymers described in Japanese Patent Laid-Open Nos. 45-26223 and 45-26224. However, this method shows relatively good physical properties but has a disadvantage of poor compatibility between PBT and α-olefin copolymers, resulting in inferior physical properties of molded articles. U.S. Patent Nos. 4,485,212 and 4,558,096 disclose methods for adding a graft copolymer of styrene and acrylonitrile to an PBT in an α-olefin copolymer. According to this method, the impact strength of the PBT resin is improved and the compatibility between the polyester and the α-olefin copolymer is slightly improved, but it is not satisfactory.

Korean Patent No. 92-26260 discloses a method of improving the impact strength and elongation by using tetramethylene glycol, isophthalate and 1,4-cyclohexane dimethanol as a modifier in a transesterification reaction, but the type of modifier added There are many and the increase in physical properties is not satisfactory.

Accordingly, the present inventors have developed a method for producing a PBT resin composition having improved compatibility between polyester and a modifier and improved impact resistance and physical properties.

Purpose of the Invention

An object of the present invention is to provide a method for producing a thermoplastic PBT resin composition with improved impact strength by adding a modifier.

Another object of the present invention is to provide a method for producing a PBT resin composition having improved compatibility between polyester and modifier.

The above and other objects of the present invention can be achieved by the present invention described below.

Summary of the Invention

The present invention comprises the step of esterifying dimethyl terephthalate, 1,4-butanediol, a modifier and a reaction catalyst to produce a reactant, and adding a stabilizer to the reactant and condensation polymerization to produce a polymer, or the polymer 60 to PBT resin composition excellent in impact resistance, characterized in that it further comprises the step of melt-kneading by adding the lubricant 6phr (weight part relative to 100% by weight of the mixture) to the antioxidant to 95% by weight and 5 to 40% by weight glass fiber It relates to a manufacturing method of. The PBT resin composition uses an organotitanium compound as a reaction catalyst and a phosphorus compound as a stabilizer.

The modifier is preferably 10 to 30% by weight based on the bifunctional carboxylic acid, the reaction catalyst is used from 0.005 to 0.5% by weight with respect to 100% by weight of the polymer, 0.01 to 0.1% by weight is preferred. The stabilizer is used in an amount of 0.005 to 0.5% by weight based on 100% by weight of the polymer, and preferably 0.01 to 0.1% by weight.

Detailed Description of the Invention

The present invention comprises a step of esterifying dimethyl terephthalate, 1,4-butanediol, a modifier and a reaction catalyst to produce a reactant, and adding a stabilizer to the reactant and condensation polymerization to produce a polymer. It relates to a process for producing an excellent PBT resin composition.

The present invention also esterifies dimethyl terephthalate, 1,4-butanediol, a modifier and a reaction catalyst to produce a reactant, adds a stabilizer to the reactant and condensates to produce a polymer, the polymer 60 to 95% by weight and The present invention relates to a method of producing a PBT resin composition having excellent impact resistance, comprising the step of melt kneading by adding 6 phr of an antioxidant and a lubricant to 5 to 40% by weight of glass fibers. The PBT resin composition uses an organic titanium compound as a catalyst and a phosphorus compound as a stabilizer.

The modifier used in the present invention is a compound having the following structural formula (I), which is added together with dimethyl terephthalate before the transesterification reaction starts at 10 to 30% by weight based on the bifunctional carboxylic acid.

In which R is H or CH ₃ . When R is H the modifier is dimethyldimer acid and when R is CH ₃ the modifier is dimethyldimerate.

The titanium compound used as the reaction catalyst is tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, tetra (2-ethylhexyl) titanate and tetraisopropyl (dioctyl) phosphate titanate alone or two kinds. The above mixture is preferable. The reaction catalyst is used in an amount of 0.005 to 0.5% by weight based on 100% by weight of the polymer, and preferably 0.01 to 0.1% by weight.

The stabilizers include phosphoric acid, triphenylphosphate, trimethylphosphate, triisodecylphosphate and tri- (2,4-di-t-butylphenyl) phosphate, 3,5-di-t-butyl-4-hydroxybenzylphosphate Phonic acid can be used individually or in mixture of 2 or more types. The reaction catalyst is used in an amount of 0.005 to 0.5% by weight based on 100% by weight of the polymer, and preferably 0.01 to 0.1% by weight.

Hindered phenol type is used as the antioxidant to express thermal stability, and lubrication agent is used as ethylene bis stearin amide to increase fluidity.

The method for producing a thermoplastic PBT resin composition having improved impact resistance according to the present invention will be described in detail below.

Dimethyl terephthalate, 1,4-butanediol, and a modifier are added to the reactor, a reaction catalyst is added before the esterification reaction, and then heated at a temperature of 140 to 210 ° C. for 2 hours. Methanol generated during the esterification reaction is released from the reactor and left at the same temperature for about 30 minutes to complete the esterification reaction and then stabilizer is added.

After transferring the esterification reaction prepared in the above method to the condensation polymerization reactor, the pressure was gradually reduced to 0.5 torr or less, and stirred at a temperature of 230 to 250 ° C. for 1 to 2 hours to prepare a polymer. The polymer is dried in a dehumidifying dryer at a temperature of 120 ° C. such that the moisture content is 0.01% by weight or less to prepare a PBT resin composition.

Or 60 to 95% by weight of the polymer and 5 to 40% by weight of glass fiber, a hindered antioxidant and an ethylene bis stearin amide-based lubricant are added, followed by melt training in an extruder heated to 250 ° C. to produce an extrudate. The extrudate is dried in a dehumidifying dryer at a temperature of 120 ° C. such that the moisture content is 0.01% by weight or less to prepare a PBT resin composition.

The present invention will be embodied by the following examples, which are only illustrative of the present invention and do not limit or limit the scope of the present invention.

Example

The contents of the components used in Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1 below.

The measurement results of the physical properties of the test specimens prepared in Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 2 below.

Example 1

45 kg of dimethyl terephthalate, 28 kg of 1,4-butanediol and 5 kg of dimethyldimerate were added to the reactor, 20 g of tetrabutyl titanate was added to the reactor before the esterification reaction, and heated at a temperature of about 180 ° C. for 2 hours. After standing at isothermal for about 30 minutes to complete the esterification reaction, a stabilizer was added.

The esterification reactant was transferred to a condensation polymerization reactor, and then gradually reduced in pressure to 0.5 torr or less, and stirred at a temperature of 240 ° C. for about 1 hour to prepare a polymer having an intrinsic viscosity of 0.88 dl / g. The polymer was dried in a dehumidifying dryer at a temperature of 120 ° C. for 4 hours so that the moisture content was 0.01% by weight or less, and the test piece was molded by an injection molding machine.

Example 2

Melting in an extruder heated to 250 ° C. after adding 0.6 phr of a hindered phenol-based antioxidant and an ethylenebisstearin amide-based lubricant to 90 wt% of the polymer and 10 wt% of glass fiber prepared in the same manner as in the polymer of Example 1 The mixture was kneaded to prepare a chip. The chip prepared as described above was dried in a dehumidifying dryer at a temperature of 120 ° C. for 4 hours so that the moisture content was 0.01% by weight or less, and the test piece was molded by an injection machine.

Example 3

The test piece was molded in the same manner as in Example 2, except that 80 wt% of the polymer and 20 wt% of the glass fiber were used.

Example 4

The test piece was molded in the same manner as in Example 2, except that 70% by weight of the polymer and 30% by weight of glass fiber were used.

Comparative Example 1

45 kg of dimethyl terephthalate and 28 kg of 1,4-butanediol were added to the reactor, and 20 g of tetrabutyl titanate was added to the reactor before the esterification reaction, followed by heating at a temperature of about 180 ° C. for 2 hours. After standing at isothermal for about 30 minutes to complete the esterification reaction, a stabilizer was added.

The esterification reactant was transferred to a condensation polymerization reactor, and then gradually reduced in pressure to 0.5 torr or less, and stirred at a temperature of 240 ° C. for about 1 hour to prepare a polymer having an intrinsic viscosity of 0.88 dl / g. The polymer was dried in a dehumidifying dryer at a temperature of 120 ° C. for 4 hours so that the moisture content was 0.01% by weight or less, and the test piece was molded by an injection molding machine.

Comparative Example 2

In an extruder heated to 250 ° C. after adding 0.6 phr of hindered phenol-based antioxidant and ethylenebisstearine amide-based lubricant to 90% by weight of polymer and 10% by weight of glass fiber prepared in the same manner as the polymer of Comparative Example 1 Melt kneading was made in the form of chips. The chip prepared as described above was dried in a dehumidifying dryer at a temperature of 120 ° C. for 4 hours so that the moisture content was 0.01% by weight or less, and the test piece was molded by an injection machine.

Comparative Example 3

The test piece was molded in the same manner as in Comparative Example 2 except that 80 wt% of the polymer and 20 wt% of the glass fiber were used.

Comparative Example 4

The test piece was molded in the same manner as in Comparative Example 2 except that 70% by weight of the polymer and 30% by weight of glass fiber were used.

Table 1

Intrinsic viscosity, tensile strength, flexural strength, flexural modulus, impact strength, and heat deflection temperature were measured for the molded specimens, and the results are shown in Table 2 below.

TABLE 2

Property measurement method:

1. Intrinsic viscosity: measured at 35 ° C. with an orthochlorophenol solvent.

2. Tensile strength: measured according to ASTM D-638

3. Flexural strength: measured according to ASTM D-790.

4. Flexural modulus: measured according to ASTM D-790.

5. Impact strength: measured by Izod-Notched at room temperature (23 ℃) according to ASTM D-256 and the thickness of the specimen was l / 4 ".

6. Heat deflection temperature: measured under the condition of 18.6kg / cm ² according to ASTM D-648.

By using dimethyl dimerate as a modifier in Table 2, it can be seen that physical properties such as impact strength, tensile strength, flexural strength, flexural modulus, impact strength, and heat deformation temperature are improved.

Simple modifications and variations of the present invention can be readily made by those skilled in the art, and all such variations or modifications can be regarded as belonging to the scope of the present invention.

Claims (4)

Esterification of dimethyl terephthalate, 1,4-butanediol, a modifier of formula (I) and a reaction catalyst to produce a reactant; Adding a stabilizer to the reactants and condensation polymerization to produce a polymer; And melt kneading by adding 6 phr of an antioxidant and a lubricant to 60 to 95% by weight of the polymer and 5 to 40% by weight of glass fiber; Method for producing a PBT resin composition, characterized in that consisting of steps.

Wherein R is H or CH ₃ The method of claim 1, wherein the reaction catalyst is tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, tetra (2-ethylhexyl) titanate and tetraisopropyl (dioctyl) phosphate titanate alone or two kinds. It is selected from the group which consists of the above mixture, The manufacturing method of the PBT resin composition characterized by the above-mentioned. The method of claim 1, wherein the stabilizer is phosphoric acid, triphenylphosphate, trimethylphosphate, triisodecylphosphate and tri- (2,4-di-t-butylphenyl) phosphate, 3,5-di-t-butyl- A method for producing a PBT resin composition, characterized in that 4-hydroxybenzylphosphonic acid is selected from the group consisting of single or mixtures of two or more. The method of claim 1, wherein the modifier is a method for producing a PBT resin composition, characterized in that 10 to 30% by weight relative to the bifunctional carboxylic acid.