JPS63179925A - Production of polyester - Google Patents

Abstract

PURPOSE:To prolong spinneret exchange interval and obtain a polyester having excellent spinning and process performance thereafter, by adding a specific hindered amine based compound and carrying out polycondensation in the presence of an antimony compound. CONSTITUTION:The aimed polymer obtained by, e.g. ester interchange reaction, etc., of (A) a bifunctional carboxylic acid consisting essentially of terephthalic acid (ester-forming derivative) with (B) a glycol consisting essentially of ethylene glycol to form a low polymer and adding (C) an antimony compound, e.g. antinomy trioxide, etc., as a polymerization catalyst, then (D) a hindered amine based compound, expressed by the formula and having >=3,000 average molecular weight, e.g. polycondensate of dimethyl succinate with 1-(2-hydroxyethyl)-4- hydroxy-2,2,6,6-tetramethylpiperidine, etc., in an amount of 0.01-1.0wt.% based on the polyester and carrying out polycondensation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing polyester with excellent spinnability.

(Prior Art) Polyesters, particularly polyesters containing terephthalic acid as the main acid component, have excellent mechanical, physical, and chemical properties, and are therefore widely used in fibers, films, and other molded products.

Among such polyesters, polyesters whose main glycol component is ethylene glyfur, tetramethylene glycol, hexamethylene glycol or cyclobequifun-1,4-dimethylol are important.

Such polyesters, such as polyethylene terephthalate, are produced by heating ethylene glycol ester of terephthalic acid and/or its low polymer under reduced pressure to cause a polycondensation reaction. The polyester thus obtained is usually extruded in a molten state into a fiber form through fine holes (spinning holes), and then stretched for practical use.

In addition, the above polycondensation reaction can be carried out by using a catalyst.
For the first time, the reaction proceeds smoothly and a commercially valuable polyester can be obtained, and the reaction rate and the quality of the obtained polyester are greatly influenced by the type of catalyst used.

Conventionally, antimony compounds such as antimony trioxide have been the most widely used polycondensation catalysts because they have an excellent effect of promoting the 1-condensation reaction and can produce polyesters with relatively good color tone. However, the polyester obtained using such an antimony compound has a disadvantage that the moldability is 1% and the spinnability is poor.In other words, when the polyester obtained using the antimony compound as a polycondensation catalyst is melt-spun, A bending phenomenon (hereinafter referred to as "venting") of the polymer flow occurs in the outside and surrounding areas of the spinning hole within a short time after the start of spinning, causing frequent wraps during spinning and stretching, eventually making spinning itself impossible. When bending occurs, it is necessary to stop spinning and replace the spinneret, which significantly impedes production.

In order to overcome this drawback, in order to improve the release properties of the polymer stream from the spinneret surface, we have investigated the use of release agents such as silicone, the material of the spinneret, the shape of the spinneret, and the use of additives. Various measures are being considered, including consideration of However, none of these effects were sufficient.

(Problems to be Solved) In order to solve the above-mentioned drawbacks, the present inventors have made extensive studies on bending during melt spinning of polyester, and have found that foreign matter (hereinafter referred to as It has been learned that there is a direct relationship between spinneret surface foreign matter (sometimes referred to as foreign matter on the spinneret surface) and bending, and that bending can be prevented by suppressing the adhesion and accumulation of spinneret foreign matter. Furthermore, when we analyzed the foreign matter on the spinneret surface, we found that the main component was the antimony component used as a polycondensation catalyst, and that the antimony compound in the polymer sublimated during spinning to become foreign matter on the spinneret surface. .

Based on these findings, the present inventors conducted intensive studies to reduce the sublimation of antimony compounds during spinning, and found that when polyester obtained by adding a high molecular weight hindered amine compound during polyester production is subjected to melt spinning, The present invention was achieved by finding that the amount of foreign matter deposited on the spinneret surface is extremely small.

(Structure of the Invention) That is, the present invention relates to the production of polyester by carrying out a polycondensation reaction in the presence of an antimony compound using a glycol ester of a difunctional carboxylic acid, mainly terephthalic acid, and/or a low polymer thereof as a catalyst. , at any stage, a hindered amine compound represented by the following general formula (I1) having an average molecular weight of 3,000 or more is added to the polyester in a ratio of 0,
This is a method for producing polyester characterized by adding 01 to 1.0% by weight.

The difunctional carboxylic acids used in the method of the present invention include:
The main target is terephthalic acid, and its ester-forming derivatives include lower furkyl esters having 1 to 4 carbon atoms,
Phenyl esters and the like are preferably used. Further, a part of this terephthalic acid component (usually 20 molar or less) may be replaced with another difunctional carboxylic acid or an ester-forming derivative thereof. Examples of other difunctional carboxylic acids include inphthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenylmethane dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxyethane dicarboxylic acid, and β-hydroxyethoxybenzoic acid. Difunctional aromatic carboxylic acids such as sebacic acid, 7-divic acid.

Examples include difunctional aliphatic carboxylic acids such as oxalic acid, and difunctional alicyclic carboxylic acids such as 1,4-cyclohexanedicarboxylic acid.

As the glycol, ethylene glycol is mainly used, and as its ester-forming derivative, ethylene oxide is particularly preferably used. Others include trimethylene glycol.

Aliphatic glycols such as tetramethylene glycol, hexamethylene glycol, and cyclohexane-1,4-dimethylol may be used, and two or more types of these glycols may be used.

A specific method for producing a glycol ester and/or a low polymer thereof from such a difunctional carboxylic acid compound and glyfur includes, for example, ethylene glycol ester of terephthalic acid and/or its low polymer used for producing polyethylene terephthalate. Regarding low polymers, the following methods are generally used: a direct esterification reaction between terephthalic acid and ethylene glycol, a transesterification reaction between a lower alkyl ester of terephthalic acid and ethylene glycol, or a reaction between terephthalic acid and ethylene oxide. Adopted. Further, any catalyst can be used in these reactions as necessary.

In the method of the present invention, a heptimony compound is used as a polycondensation catalyst.

As the antimony compound used here, any antimony compound having polycondensation catalytic ability can be used. Usually antimony trioxide.

Oxides such as antimony tetroxide, antimony pentoxide,
Preferred are halides such as antimony trichloride and antimony tribromide, alcoholades such as heptimony glycolate, and especially preferred are oxides.

The hindered amine compound used in the present invention is represented by the following general formula (I1) and has an average molecular weight of 3000 or more.

As the hindered amine compound represented by the general formula ([1], a polycondensate of dimethyl conoate and 1-(2-hydroxyethyl)-4-hydroxy-2,2°6.6-titramethylpiperidine is used. preferable.

The average molecular weight of this hindered amine compound is 300.
It may be 0 or more, but if the average molecular weight exceeds 20,000, it tends to be difficult to dissolve in polyester.
The upper limit of the average molecular weight is preferably 20,000 or less, particularly preferably an average molecular weight of 3,000 to 5,000.

Here, even if the hindered amine compound represented by the general formula el) has an average molecular weight of less than 3000, it is likely to scatter or decompose and become colored during the polycondensation reaction carried out under high temperature and high vacuum conditions, so the obtained polyester The effect of suppressing the adhesion and accumulation of foreign matter on the spinneret surface during melt spinning becomes insufficient.

Furthermore, in JP-A No. 61-22531, in order to improve the fading fastness to light of a fiber made of polyester whose dyeability has been improved by copolymerizing polyoxyalkylene glycol, etc., a hindered amine having a molecular weight of 3000 or more is added to polyester. Although the addition of a systemized metal compound is shown, the hindered amine compound represented by the general formula (I) used in the present invention is not shown.

Moreover, the polyester obtained by adding the hindered amine compound shown below in the above-mentioned JP-A-Sho is unable to suppress foreign matter deposited on the spinneret surface, as shown in the comparative example below. .

In the present invention, the hindered amine compound represented by the general formula (I1) and other hindered amine compounds may be used in combination.

Other hindered amine compounds include, for example, 2-
(3,5-di-t-butyl-4-hydroxybenzyl)
-2-n-butylmaponic acid bis(I+2?2+616
-bentamethyl-4-piperidyl).

2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-propylmalonic acid bis(I1212
1616-bentamethyl-4-piperidyl).

2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-pendelmalonate bis(I) 2,2
, 6.6-bentamethyl-4-piperidyl).

2-(3,5-di-t-butyl-4-human-xybenzyl)-2-n-butylmalonic acid bis(2°2.6.
bis(2,2,6,6-tetramethyl-4-piperidyl) 11bacate,
Bissebacate (L2+2+6+6-bentamethyl-4
-piperidyl), azelaic acid bis(2,2,6,6-
tetramethyl-4-piperidyl), bisperate (2
, 2,6,6-tetramethyl-4-piperidyl), bis(2゜2.6.6-tetramethyl-4-piperidyl) pimelate, bis(2,2,6,6-tetramethyl 7-dipate) -4-piperidyl), poly((s (I1113
13-tetramethylbutyl)imino-1,3,5-t'
) 7 gin-2.4-diyl) (2+2+6+6
-tetramethyl-4-piperidyl)imino]hexamethylene [[2+ 2 t 6 + 6-tetramethyl-4
-piperidyl)imino] and the like. Such hindered amine compounds may be used alone or in combination of two or more.

The amount of the hindered amine compound used in the present invention is from o to 1.0% by weight based on the polyester. If the amount is less than 0.01% by weight, the effect of suppressing the adhesion and accumulation of foreign matter on the mouthpiece, which is the objective of the present invention, will be insufficient.
If it exceeds 1.0% by weight, no further effects can be expected.

Such hindered amine compounds may be added at any stage of producing polyester.

It may also be added during molding of polyester.

In carrying out the present invention, other polycondensation catalysts may be used in combination without departing from the purpose of the present invention, and optional additives such as colorants, matting agents, fluorescent agents, etc. may be used as necessary. Brighteners, stabilizers, ultraviolet absorbers, ether bond inhibitors, dye-facilitating agents, antistatic agents, and the like may be used.

(Function) In the production method of the present invention, a specific high molecular weight hindered amine compound, which is different from the high molecular weight hindered amine compound conventionally used to improve the fading fastness of polyester fibers, is polycondensed. As a result of using it in combination with a heptimony compound as a catalyst, even when the resulting polyester is subjected to melt spinning, it is possible to extremely reduce the adhesion and accumulation of foreign matter around the outside of the spinning hole, and it is stable for a long time without causing bending. It can be spun by spinning.

(Effect of the invention) When the polyester obtained by the production method of the present invention is melt-spun, the time until bending can be significantly extended, so the spinneret exchange cycle can be extended significantly, and the industrial effect is remarkable. . Moreover, the effects produced are extremely remarkable, such as not only the spinning condition but also the process condition after spinning can be significantly improved.

(Example) Next, the present invention will be explained in further detail by giving examples.

In the examples, parts are parts by weight, and ■ is the intrinsic viscosity determined from the value measured at 30° C. in Olunc-purphenol solvent. In addition, the spinnability was determined using a spinneret with 30 spinning holes with a diameter of 0.3 u, and the output rate was 80 II/Ill +
It is shown by the height of foreign matter around the outside of the spinning hole and the state of bending between them when melt spinning was carried out at a discharge temperature of 285°C and a winding speed of 1200 m/yy for 7 days. The drawn yarn was drawn at a drawing temperature of 85°C and a drawing ratio of 3.
It is shown as the wrap ratio when the film is stretched 5 times at a stretching speed of 1100 rn/period to form a 150 denier/30 filament of 2.51 q;+ turns.

Example 1 100 parts of dimethyl terephthalate, 7 parts of ethylene glycol
0 parts and 0.02 manganese acetate as transesterification catalyst
heating the two-part mixture from 150°C to 240°C;
It took 4 hours to carry out the transesterification reaction while distilling off methanol.

Here, 0.05 part of antimony trioxide was added as a polycondensation catalyst, part of dimegyl (2-hydroxyethyl) succinate was added as a hindered amine compound, and trimethylsulfosphine (trimethylsulfosphine) was added as a stabilizer.
．． An ethylene glycol slurry containing 0.020 parts and 0.3 parts of titanium dioxide as a matting agent was added. After that, 25
The temperature was raised from 0°C to 290°C and a polycondensation reaction was carried out for 4 hours under reduced pressure of +71°C or less to obtain polyethylene terephthalate ((72)0.637).

No bending was observed during the 7-day spinning period of this polymer, and the spinnability was extremely good, and the height of the spinneret foreign matter after 7 days was only 4 μm. Furthermore, the lapping ratio during stretching was 0.15%, and the stretchability was also extremely good.

Example 2 Polyethylene terephthalate of 7fi0.640 was obtained in the same manner as in Example 1, except that the average molecular weight of the hindered amine compound used in Example 1 was changed to 3000.

No inding was observed during the 7-day spinning period of the conophorimer, and the spinnability was extremely good, and the height of foreign matter on the spinneret surface after 7 days was only 10 μm. Furthermore, the lapping ratio during stretching was as low as 0.2%, and the stretchability was also extremely good.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the hindered amine compound was not added (b) 0.641 polyethylene terephthalate was obtained.

During the 7-day spinning period of this polymer, bending occurred from the 5th day after the start of spinning, and after 7 days, the height of the foreign matter on the spinneret surface was as high as 42μ, and the drawing wrap ratio was also poor at 6%.

Comparative Example 2 Polyethylene terephthalate of @0.639 was obtained in the same manner as in Example 1, except that the hindered amine compound shown below was used instead of the hindered amine compound used in Example 1. During the 7-day spinning period, venting occurred from the 6th day after the start of spinning, and after 7 days, the height of foreign matter on the spinneret surface was as high as 35μ, and the wrap rate during stretching was poor at 4.5%. .

H3

Claims (1)

[Claims] In producing a polyester by polycondensing a glycol ester of a difunctional carboxylic acid mainly containing terephthalic acid and/or its low polymer in the presence of an antimony compound as a polycondensation catalyst, any At this stage, the following general formula (
A hindered amine compound represented by I) with an average molecular weight of 3,000 or more is added to the polyester from
A method for producing polyester characterized by adding 1.0% by weight. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ ・・・・・・・・・(I)