KR100567105B1 - Method for producing polytrimethylene terephthalate resin with improved heat resistance and melt stability - Google Patents

Abstract

The present invention relates to a method for preparing a polytrimethylene terephthalate resin, and more particularly, to a method for preparing a polytrimethylene terephthalate resin having improved heat resistance and melt stability by copolymerizing 1,4-cyclohexanedimethanol. . The polytrimethylene terephthalate resin prepared by the method of the present invention has excellent heat resistance and melt stability compared to the existing polytrimethylene terephthalate resin, which not only improves workability and process stability during post processing, but also shortens the polymerization reaction time. Productivity and color improvement effect.

Description

Method for preparing polytrimethylene terephthalate resin having improved heat resistance and melt stability

The present invention relates to a method for preparing a polytrimethylene terephthalate resin copolymerized with 1,4-cyclohexanedimethanol to improve heat resistance and melt stability. More specifically, 1,4-cyclohexanedimethanol is used as terephthalic acid (TPA). Or 1 to 38 parts by weight with respect to 100 parts by weight of its ester derivatives to improve the heat resistance and melt stability of the polytrimethylene terephthalate resin to improve processability and process stability during post-processing, and to shorten the polymerization reaction time And it relates to a method for producing a polytrimethylene terephthalate resin having a color improvement effect.

Recently, interest in polytrimethylene terephthalate resin in polyester is increasing, and many researches and developments for commercialization are in progress. In particular, elasticity and dyeing property are superior to existing polyethylene terephthalate or polybutylene terephthalate. It is known that the development of applications for fibers for carpets and garments, in addition to engineering plastics and films for industrial use, is actively progressing.

As an example, US Pat. No. 2,465,319 describes a method for producing polytrimethylene terephthalate using sodium and magnesium catalyst, and US Pat. No. 3,671,379 describes a method for producing polytrimethylene terephthalate using titanium catalyst. Doing.

However, the polytrimethylene terephthalate resins have a low glass transition temperature, so that deformation occurs even when stored at room temperature, thereby changing physical properties, resulting in poor storage stability, and high crystallization rate, making it difficult to increase productivity in post-processing films and fibers. Do. In addition, compared to the existing polyethylene terephthalate or polybutylene terephthalate during the polymerization reaction, the reaction rate is slow, the reaction time is long, there is a disadvantage that the productivity is lowered.

Accordingly, the present inventors conducted extensive research to solve the above problems, and as a result, the polytrimethylene terephthalate resin copolymerized 1,4-cyclohexanedimethanol with terephthalic acid or its ester derivatives to improve heat resistance and melt stability. The present invention has been completed based on this finding.

Accordingly, an object of the present invention is to provide a method for producing a polytrimethylene terephthalate resin having improved heat resistance and melt stability.

The method for producing a polytrimethylene terephthalate resin of the present invention for achieving the above object is 1 to 38 parts by weight based on 100 parts by weight of 1,4-part by weight of terephthalic acid or its ester derivative in the method for producing a polytrimethylene terephthalate resin It consists of copolymerizing cyclohexane dimethanol, 42-70 parts by weight of 1,3-propylene glycol and 0.02-0.2 parts by weight of reaction catalyst.

Hereinafter, the present invention will be described in more detail.

The polytrimethylene terephthalate resin of the present invention comprises 1 to 38 parts by weight of 1,4-cyclohexanedimethanol, 42 to 70 parts by weight of 1,3-propylene glycol and 0.02 to 0.2 part by weight based on 100 parts by weight of terephthalic acid or its ester derivatives. It is prepared by copolymerizing negative reaction catalyst. At this time, when the content of the 1,4-cyclohexane dimethanol is less than 1 part by weight compared to terephthalic acid (TPA) or its ester derivative, the reaction time shortening and heat resistance improvement effect is insignificant, and when it exceeds 38 parts by weight, the reaction time is shortened. And the color improvement effect is sufficient, but the crystallization rate is too slow, the physical properties of the final product is reduced. Therefore, more preferably, the copolymerization ratio of 1,4-cyclohexanedimethanol is 1 to 25 parts by weight based on 100 parts by weight of terephthalic acid (TPA) or its ester derivative. Preferred terephthalic acid or ester derivatives thereof in the present invention include terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate and the like.

In the present invention, the amount of 1,3-propylene glycol used in the polymerization is preferably 42 to 70 parts by weight based on 100 parts by weight of terephthalic acid (TPA) or an ester derivative thereof. At this time, if the amount of the component is less than 42 parts by weight, the transesterification reaction is insufficient to obtain a polymer having a desired intrinsic viscosity, if it exceeds 70 parts by weight, there is no significant effect on the polymerization reaction rate, unreacted 1,3 -It takes additional time and energy to spill propylene glycol, which increases the cost of production. Therefore, more preferably, the copolymerization ratio of the diol component is suitably 50 to 70 parts by weight based on 100 parts by weight of terephthalic acid (TPA) or an ester derivative thereof.

In the present invention, the catalyst used in the polymerization is selected from the group consisting of antimony trioxide, antimony acetate, tetrapropyl titanate and tetrabutyl titanate, and tetrabutyl titanate is used in view of shortening the polymerization reaction time and color improving effect. It is preferable. The amount of the reaction catalyst is preferably 0.02 to 0.2 parts by weight based on 100 parts by weight of terephthalic acid or its ester derivative. If the amount of the catalyst is less than 0.02 parts by weight, the reaction rate is slow and the reaction time is long, resulting in a decrease in productivity. If the content exceeds 0.2 parts by weight, the reaction time shortening effect is not great, but there is a problem that the color deteriorates.

In the present invention, the intrinsic viscosity of the resin finally obtained during copolymerization should be 0.60 or more. If the intrinsic viscosity of the polytrimethylene terephthalate resin is less than 0.60, the molecular weight is too low, so that the effect of improving heat resistance is hardly exhibited.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following Examples.

The unit "parts" means "parts by weight" unless stated otherwise.

Physical properties shown in the following Examples and Comparative Examples are measured by the following method.

1. Intrinsic viscosity (IV): After dissolving in 0.12% concentration in 150 ° C ortho-chlorophenol, it is measured using a Ubelrod viscometer in a 35 ° C thermostat.

2. Color: Measured with chips crystallized at 120 ° C. for 3 hours using Pacific Scientific's Colorgard System.

3. Differential Scanning Calorimetry (DSG): Using Perkin-Eimer's DSC-7 model, the temperature was first raised to 260 ° C at a temperature increase rate of 10 ° C / min, maintained for 3 minutes and quenched with liquid nitrogen. After heating up to 260 ° C at a temperature increase rate of 10 ° C / min for the second time, it is maintained for 3 minutes and cooled down to 100 ° C at a rate of 10 ° C / min. (Tm) and melt crystallization temperature (Tmc) are measured.

4. Melt Stability: Using a Physica Rheometer UM-100 model, the viscosity change over two hours at 265 ° C. was measured with a shear rate of 10 / sec using a plate / plate system.

Example 1

1164 parts of dimethyl terephthalate (DMT), 26 parts of 1,4-cyclohexanedimethanol, 762 parts of 1,3-propylene glycol and 0.46 parts of tetrabutyl titanate were placed in a reactor equipped with a stirrer and an outlet condenser. React while raising to 230 ° C. At this time, the produced methanol is distilled out of the system and transesterified. When the methanol is discharged, 1 part of trimethyl phosphate is added as a stabilizer, and stirred for 10 minutes. Move. Here, while increasing the internal temperature from 230 ℃ to 260 ℃ by gradually reducing the pressure to 0.1mmHg at atmospheric pressure to remove the 1,3-propylene glycol while reacting until the desired level of intrinsic viscosity is reached and discharged and needle bed Cut with The intrinsic viscosity of the polytrimethylene terephthalate resin thus prepared was 0.685, and the chip was crystallized in a vacuum dryer for 3 hours at 120 ° C. for analysis. As a result, a copolymer having a color-b value of 6.1 was obtained. . In addition, differential scanning calorimetry, melt stability, and the like were analyzed.

The conditions, intrinsic viscosity, and color of the present example are shown in Table 1 below, and the results of differential scanning calorimetry are shown in Table 2 below. And, the results of melt stability analysis are summarized in Table 3 below.

Examples 2 to 3

Polymerization was carried out in the same manner as in Example 1, except that the content of 1,4-cyclohexanedimethanol was changed as shown in Table 1 below.

Comparative Example 1

Polymerization was carried out in the same manner as in Example 1, except that 1,4-cyclohexanedimethanol was not added.

* CHDM: 1,4-cyclohexanedimethanol

* DMT: Dimethyl Terephthalate

As described above, the polytrimethylene terephthalate resin prepared by the manufacturing method of the present invention has a shorter polymerization reaction time than the conventional polytrimethylene terephthalate resin, resulting in improved polymerization productivity and color, and improved heat resistance and Reduced crystallization rate and wider range of processing conditions facilitate process management. In addition, the melt stability is excellent compared to the existing polytrimethylene terephthalate resin is very useful industrially.

Claims (4)

In the method for producing a polytrimethylene terephthalate resin, (i) 100 parts by weight of terephthalic acid or an ester derivative thereof, and (ii) 1 to 38 parts by weight of 1,4-cyclohexanedimethanol as a diol component and 1,3-propylene glycol 42 to 70 parts by weight of (i) copolymerization in the presence of 0.02 to 0.2 parts by weight of the reaction catalyst to have a polyvisethylene terephthalate resin with improved heat resistance and melt stability characterized in that it has an intrinsic viscosity of 0.6 or more. The method of claim 1, wherein the reaction catalyst is one selected from the group consisting of antimony trioxide, antimony acetate, tetrapropyl titanate and tetrabutyl titanate. . The polytrimethylene terephthalate resin having improved heat resistance and melt stability according to claim 1, wherein the copolymerization ratio of 1,4-cyclohexanedimethanol is 1 to 25 parts by weight based on 100 parts by weight of terephthalic acid or its ester derivative. Manufacturing method. The method of claim 1, wherein the copolymerization ratio of the diol component is 50 to 70 parts by weight based on 100 parts by weight of terephthalic acid or ester derivatives thereof.