JPS5855975B2 - Polyester material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyester, and more specifically,
This invention relates to a method for producing polyester using a specific titanium catalyst.

Conventionally, terephthalic acid (hereinafter referred to as rTPAJ) has been used.

) and 1,4-butanediol (hereinafter referred to as "1,4BGJ").

) and then polycondensed to form a high viscosity polybutylene terephthalate (hereinafter referred to as rPBTJ).

) In the case of the so-called direct polymerization method for producing esters, the esterification reaction is carried out without a catalyst or an inorganic titanium compound, such as a titanium fluoride compound, is used as a catalyst.

In the case of esterification without a catalyst, it is necessary to carry out the esterification in the presence of a large excess of 1.4BG in order to advance the subsequent polycondensation reaction to a predetermined stage.
Tetrahydrofuran (hereinafter referred to as 1
-It's called THFJ.

) is also a large amount of by-product.

On the other hand, even when a catalyst is used, it is difficult to obtain PBT with a high degree of polymerization when a conventionally known inorganic titanium compound catalyst is used, and the amount of by-product THF is large, especially when using a metal halide such as TiCl4. HCI is generated by hydrolysis, which is undesirable.

Furthermore, when using normal β-titanic acid, it is necessary to use it after pulverizing it so that it does not easily splinter in the reaction system.

The present inventors conducted various studies in order to improve these drawbacks and find an inorganic titanium compound catalyst that has high activity in both esterification and polycondensation reactions and provides a polyester mainly composed of PBT with a high degree of polymerization. As a result, we have arrived at the present invention.

That is, in the present invention, when producing a polyester mainly composed of PBT by esterification reaction of TPA and 1.4BG and subsequent polycondensation reaction, the molar ratio of 1.4BG/TPA is in the range of 1.05 to 3.0. and adding a hydrolyzate of titanium halide or titanium sulfate as a catalyst and maintaining the temperature within a temperature range of 150 to 270°C for ester AAB, and then polycondensing the esterified product. It is in the manufacturing method.

The present invention will be explained in detail below.

The esterification reaction applied to the present invention is the esterification between an acid component mainly consisting of TPA and a glycol component mainly consisting of 1,4BG, or bis-(ω-hydroxybutyl ) A reaction between the 1,4BG end of terephthalate or oligomer and TPA, and a reaction between the TPA end and 1,4BG.

In the present invention, the 1.4BG/TPA molar ratio refers to the ratio of the 1.4BG component to the TPA component in the reaction mixture;
．． 05-3.0 preferably maintained at 1.3-2.5.

1.4 If the B G / TPA molar ratio is too small, esterification will not proceed sufficiently and a large amount of unreacted TPA will remain in the system, preventing the polycondensation reaction from proceeding sufficiently and only a low polymer will be obtained. I can't do it.

On the other hand, if the molar ratio is too large, the amount of THF by-product will increase and the amount of 1.4BG required for producing the polyester will increase, which is disadvantageous.

The prepared mixture is heated to a temperature of 150 to 270°C, particularly 180 to 250°C, with stirring.
・Control the temperature to prevent 4BG from distilling out as much as possible.

During the esterification, a hydrolyzate of titanium chloride or titanium sulfate is added before or after the start of the reaction.

The hydrolyzate can be prepared using conventional methods such as mixing and heating titanium tetrachloride with water, mixing or heating an aqueous solution of an alkaline compound such as caustic soda, potassium carbonate, or ammonia, methanol, ethanol, or ethylene glycol. , acetone, benzene, acetic acid, carbon tetrachloride, or the like, and blowing heated steam into the solution.

The hydrolysis reaction is usually carried out at a temperature of 0°C or higher and 100°C or lower, but preferably at room temperature or lower.

The hydrolyzate is filtered, washed with an organic solvent such as water or alcohol, and adjusted to a predetermined moisture content as necessary for use, or in order to obtain PBT with a high degree of polymerization, the moisture content is 50 to 95%.
It is particularly preferable to adjust the amount to % by weight.

The hydrolyzate is preferably used by being uniformly dispersed in 1.4BG, and the amount of Ti added is about 0.005 to 0.1% by weight based on the final polymer.

The polycondensation reaction is carried out by gradually increasing the temperature in the system to 220~
While maintaining the temperature in the range of about 270° C., pressure reduction is started at the same time so that the temperature is finally below ITorr.

According to the present invention, the amount of by-produced THFO is small and the terminal carboxyl concentration is low, that is, P with good thermal stability.
BT can be produced industrially more advantageously than when conventional inorganic titanium compounds are used as catalysts.

The present invention will be further explained below with reference to Examples.

Example 1 ■ 5rnl of titanium tetrachloride is added to 00rILl of water while maintaining the temperature below 10°C.

Aqueous ammonia is added to this aqueous solution to adjust the pH to 8 to 9.

After filtering the produced white precipitate and washing with water, the resulting cake-like white solid (water content 85 wt%) is dispersed in 1.48 G and used as a catalyst.

TPA302gr, 1-1-4BG326, and the prepared catalyst slurry were each charged at 40 ppm of TPA in terms of Ti into a reactor equipped with a rectification column, and the esterification reaction was carried out at 220°C while distilling off the water produced. .

The reaction was completed in 80 minutes, and the distillate (including distilled water)
By-product THF in 147 gr was 58 gr.

At the end of the reaction, what was initially a cloudy slurry in which TPA was dispersed in 1.4BG was changed to TPA and 1.4B.
G reacts by esterification reaction to become a soluble oligomer, and insoluble TPA disappears, that is, 100%
The time point was defined as the point at which the reaction solution became transparent after the reaction.

When polycondensing this reaction product, the temperature is raised to 245° C., and at the same time the pressure is gradually reduced to finally reduce the pressure to below ITorr.

The polycondensation reaction was completed in 100 minutes, and the resulting polymer had an intrinsic viscosity of 0.908 and a terminal carboxyl group concentration of 6.
It was 6 eq/106 gr.

Comparative Example 1 302gr of TPA, 326gr of 1.4BG were charged into a reactor equipped with a rectification column, and while distilling off the water produced, 2gr.
Esterification was carried out at 20°C.

The reaction mixture did not become clear even after 6 hours.

Moreover, the by-product THF in the distillate was 133 gr.

The reaction mixture was subjected to polycondensation reaction in the same manner as in Example 1, but only a low polymer was obtained.

Example 2 100rILl of 0. Titanium sulfate 51 is dissolved in IN sulfuric acid while maintaining the temperature below 10°C.

Aqueous ammonia is added to this aqueous solution to adjust the pH to 8 to 9.

After the produced white precipitate is filtered once and washed with water, the resulting cake-like white solid (water content 90 wt%) is dispersed in 1.48 G and used as a catalyst.

TPA302gr, 1.48G326gr, and the prepared catalyst slurry were each charged in a Ti equivalent amount of 40ppm relative to TPA into a reactor equipped with a rectification column, and an esterification reaction was carried out at 220°C while distilling off the produced water.

The reaction was completed in 80 minutes and the distillate (containing distilled water) was obtained.

) The by-product THF in 150gr was 59gr.

When polycondensing this reaction product, the temperature is raised to 245° C., and at the same time the pressure is gradually reduced to finally reduce the pressure to below ITorr.

The polycondensation reaction was completed in 100 minutes, and the resulting polymer had an intrinsic viscosity of Q, 921, and a terminal carboxyl group concentration of 7.1e.
q/106gr.

Comparative Example 2 302gr of TPA and 652gr of 1.4BG were charged into a reactor equipped with a rectification column, and while distilling off the water produced, 2gr.
Esterification was carried out at 20°C.

The reaction was completed in 200 minutes, and the by-product THF in the distillate was 270 gr.

This reaction mixture was subjected to a polycondensation reaction in the same manner as in Example 1.

The polycondensation reaction was completed in 120 minutes, and the resulting polymer had an intrinsic viscosity of 0.960 and a terminal carboxyl group concentration of 10e.
It was q/106gr.

Comparative Example 3 Example 1 except that Zn(OH)2 is used as a catalyst
Esterification was carried out in the same manner as above, but it did not become transparent even after 6 hours.

Claims (1)

[Claims] 1 When producing a polyester mainly composed of polybutylene terephthalate by esterification reaction of terephthalic acid and 1,4-butanediol and subsequent polycondensation reaction, the molar ratio of 1,4-butanediol/terephthalic acid was set to 1.05. to 3.0, adding a hydrolyzate of titanium halide or titanium sulfate with a water content of 50 to 95% by weight as a catalyst, and maintaining the temperature within a temperature range of 150 to 270°C to carry out the esterification reaction. 1. A method for producing polyester, which comprises performing the following steps and then polycondensing the esterified product.