KR930007880B1 - Process for preparation of polyester - Google Patents

Abstract

This refers to a new polyester which inhibits excess crystalization in molecular orientation and its manufacturing method. The polyester, which has repetitive ethylene terephthalate monomer, includes 0.05-4.0 mol% compd. of formula (I). In formula R is H, C1-15 alkyl, aryl or arylalkyl. When spinning this polyester fiber at the high speed upward of 3000 m/min, end breakage is better reduced during the spinning or extension process so that total process can be stabilized and productivity is enhanced. Pref. additives are such as salicyl salicylic acid and methyl salicyl salicylate.

Description

How to prepare polyester

The present invention relates to a method for producing a polyester that can suppress excessive crystallization during molecular orientation of the polyester.

Polyester is used for various purposes because of its excellent physical and chemical properties, and is widely used as a fiber. Polyester fibers are manufactured in various ways, and recently, as the weaving technique is advanced, the winding speed during melt spinning can be greatly increased from 1,000 to 1500 m / min to 2,000 m / min or more.

In particular, the partially oriented undrawn yarn manufactured at a winding speed of 2,500 to 4,000 m / min is provided as it is to the stretching and processing process, and its use is continuously expanding.

On the other hand, ultra-fast spinning with a winding speed of 4,000 m / min has also been attempted. In such high-speed spinning, there is a problem in that trimming occurs frequently during spinning and the strength of the final product is significantly reduced.

In order to solve these drawbacks, the optimization of the radiation conditions and the structural improvement of the spinning nozzle have been attempted, but it was difficult to expect a satisfactory effect with this method.

The present inventors have investigated the causes of the problems described above, when melt spinning the polyester, when the winding speed is 2,000m / min or more, the molecular orientation is caused by the radial tension and crystallization occurs at the same time, the orientation is Since the crystallization proceeds greatly in a state in which it is not sufficiently made, the above-mentioned problem occurs, and it is found that such a phenomenon becomes more remarkable as the winding speed is increased.

Based on the above facts, polyesters with high orientation and low crystallization during high-speed spinning are continuously examined in terms of their crystallization and molecular orientation behavior, and various additives that can suppress crystallization during molecular orientation are found. In the preparation of polyester, it was found that adding a compound represented by the following general formula (I) was effective and completed the present invention.

Provided that R is one of H or an alkyl group having 1 to 15 carbon atoms, an aryl group, or an arylalkyl group.

Hereinafter, the present invention will be described in detail. In the present invention, in the production of a polyester in which the main repeating structural unit is ethylene terephthalate, the reaction of adding the compound of the general formula (I) to the acid component constituting the polyester in the polymerization step by adding 0.05 to 4.0 mol% It features.

In the present invention, when the addition amount of the compound of the general formula (I) is too small, the effect of suppressing crystallization at the time of molecular orientation is not obtained. On the contrary, when the addition amount is too large, the physical properties of the polyester deteriorate. It is good to add 0.05-5.0 mol% with respect to an acid.

If it exceeds 5 mol%, there is a decisive disadvantage in that yellowing of the chip occurs, and productivity is reduced due to excessive production of by-products and extension of reaction time.

The object of the present invention is a polyester made of polyethylene terephthalate, but is also useful for a polyester in which a part of a dicarboxylic acid component or a glycol component is substituted with another component for improving physical properties of the polyester. According to the present invention, when high-speed spinning at a spinning speed of 3,000 m / min or more, the trimming occurring during the spinning and stretching process is significantly reduced, the process is stabilized and productivity is greatly improved.

[Examples 1, 3, 5]

Salicylic salicylic acid (When R in Formula (I) is added to H) A polyester having an intrinsic viscosity of 0.65 was spun through a spinning nozzle at a spinning temperature of 285 ° C. and discharged at 44.5 g / min. The air was blown at a wind speed of 0.5 m / min to cool, concentrated and emulsified, then wound at a rate of 4,000 m / min to obtain undrawn yarn, which was stretched to a draw ratio of 1.332. At this time, the results showing the workability of the spinning and stretching as the trimming rate is shown in Table 1.

[Examples 2 and 4]

The same procedure as in Example 1 was conducted except that the polyester prepared by adding methyl salicylic salicylate (when R in Formula (I) has 1 carbon atom) was used. The results are shown in Table 1 below.

[Comparative Examples 1 and 2]

Comparative Example 1 was carried out in the same manner as in Example 1 using a polyester containing 8 mol% of the additive of Example 1 without the additive, the results are shown in Table 1.

TABLE 1

※ The radio workability is expressed as the percentage of the number of trimming occurrences (= trimming rate) to the number of trimmings and the total number of dopings (number 333) based on 1,000 hours.

※ Stretch workability is expressed as the percentage of trimming incidence (= trimming rate) at 3,000 strokes.

Claims (1)

A method for producing a polyester, wherein the polyester is prepared by adding 0.05 to 5.0 mol% of the compound of the following general formula (1) with respect to the acid component constituting the polyester. Provided that R is one of H or an alkyl group having 1 to 15 carbon atoms, an aryl group, or an arylalkyl group.