JPS6067529A - Manufacture of polyester for fiber use - Google Patents

Abstract

PURPOSE:To produce a polyester of outstanding spinnability free from foreign substances attached to cap surface in the melt spinning, by using, when carrying out polycondensation, a reaction product, as catalyst, from antimony compound and phosphoric (or phosphorous) acid salt. CONSTITUTION:In the polycondensation, in the presence of catalyst, of a glycol ester of bifunctional carboxylic acid (mainly, terephthalic acid) and/or its oligomer, a reaction product from antimony compound and phosphorous or phosphoric acid salt is used as said catalyst. Said product can be prepared by the reaction of (1) 1mol of antimony oxide with (2) 0.1-500 (pref. 1-50)mol of a phosphorous or phosphoric alkali (alkaline earth) metal salt in a solvent pref. the same glycol as that for the objective polyester.

Description

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

(Prior art) Polyester, especially polyester whose main acid component is terephthalic acid, has excellent mechanical, physical, and chemical properties, so it is used as a fiber.

Widely used for films and other molded products. Among such polyesters, ethylene glycol, tetramethylene glycol.

Hexamethenyl gelicol or cyclohexane-1,4
- Polyesters whose main glycol component is dimethylol are important.

Such polyesters, for example, polyethylene terephthalate, are produced by subjecting ethylene glycol ester of terephthalic acid and/or its low polymer to a polycondensation reaction under reduced pressure and heating. 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 process proceeds smoothly and a commercially valuable polyester can be obtained.The reaction rate and the quality of the resulting polyester are greatly influenced by the type of catalyst used.

Conventionally, antimony compounds such as antimony trioxide have been most widely used as polycondensation catalysts because they have an excellent polycondensation reaction promotion effect and can yield polyesters with relatively good color tone. . However, polyesters obtained using such antimony compounds have a drawback of poor moldability, particularly poor spinnability. That is, when polyester obtained using an antimony compound as a polycondensation catalyst is melt-spun, a bending phenomenon (hereinafter referred to as "bending") of the polymer flow occurs around the outside of the spinning hole within a short time after the start of spinning, and this causes problems in spinning and drawing. Occasionally, lapping occurs frequently and spinning itself becomes impossible. Therefore, when bending occurs, it is necessary to stop spinning and replace the spinneret, which significantly reduces production. <Is inhibited.

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 additives. A number of measures are being considered, including consideration of the following.

However, none of these effects were sufficient.

(Problems to be Solved) In order to solve the above-mentioned drawbacks, the inventors of the present invention have conducted extensive studies on bending during melt spinning of polyester, and have found that foreign matter (hereinafter referred to as I learned that there is a close relationship between foreign matter (referred to as surface foreign matter) and bending, and that bending can be prevented by suppressing the adhesion and accumulation of foreign matter on the mouth surface. Furthermore, upon analysis of such foreign matter on the spindle surface, it was found that the main component thereof 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 spindle surface.

Based on these findings, the present inventor conducted extensive research on a method for suppressing the adhesion and accumulation of foreign matter on the mouth surface by using an antimony compound as a polycondensation catalyst. The reaction product obtained by reacting with a salt or alkaline earth metal salt has high catalytic activity and extremely low sublimation property, and the polyester obtained by using this reaction product as a polycondensation catalyst cannot be melt-spun. It was found that there was significantly less foreign matter adhering to the spinneret surface during spinning, and that spinning could be carried out stably for a long period of time without bending. The present invention was completed based on this knowledge.

(Structure of the Invention) That is, the present invention involves the polycondensation reaction of glyfur esters of difunctional carboxylic acids, mainly terephthalic acid, and/or their low polymers in the presence of a catalyst to produce a polyester. This is a method for producing polyester for fibers, which is characterized in that a reaction product obtained by reacting an antimony compound with a phosphite or a phosphate in advance is used.

The difunctional carboxylic acids used in the method of the present invention include:
The main target is terephthalic acid, and as its ester-forming derivatives, lower alkyl esters having 1 to 4 carbon atoms, phenyl esters, etc. 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. Other difunctional carboxylic acids include, for example, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenylmethane dicarboxylic acid, diphenyl ether dicarboxylic acid,
Difunctional aromatic carboxylic acids such as diphenoxyethanedicarboxylic acid and β-hydroxyethoxybenzoic acid; difunctional aliphatic carboxylic acids such as sebacic acid, adipic acid, and oxalic acid; and 1,4-cyclohexanedicarboxylic acid. Examples include difunctional alicyclic carboxylic acids.

As the glycol, ethylene glycol is mainly used, and as its ester-forming derivative, ethylene oxide is particularly preferably used. Also, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, cyclohexyl? -IJ-7-1.4-
It may be an aliphatic glycol such as dimethylol, or two or more of these glycols may be used.

A specific method for producing a glycol ester and/or a low polymer thereof from such an acid component and a glycol component, and 1
2, for example, to explain the ethylene glyfur ester of sultrephthalic acid and/or its low polymer used to produce polyethylene terephthalate. A method of transesterifying a lower alkyl ester with ethylene glycol or reacting terephthalic acid with ethylene oxide is generally employed. Further, any catalyst can be used in these reactions as necessary.

The polycondensation catalyst used in the method of the present invention is a reaction product obtained by reacting an antimony compound with a phosphite or a phosphate.

As the antimony compound used here, any antimony compound can be used as long as it has polycondensation catalytic ability. Generally, oxides such as antimony trioxide, antimony tetroxide, and antimony pentoxide, halides such as antimony trichloride and antimony tribromide, and alcoholides such as antimony glycolate are preferred, and among these, oxides are preferred. Particularly preferred.

Further, as the phosphite or phosphate to be reacted with such an antimony compound, an alkali metal salt or an alkaline earth metal salt is preferable, and particularly as a phosphate, calcium phosphate, calcium phosphate-hydrogen phosphate, calcium dihydrogen phosphate , barium phosphate, barium hydrogen phosphate, barium dihydrogen phosphate, sodium phosphate, phosphoric acid
Sodium hydrogen, sodium dihydrogen phosphate, potassium phosphate, potassium hydrogen phosphate, potassium dihydrogen phosphate, etc. are preferred, and as the phosphite, calcium phosphite, calcium hydrogen phosphite, etc. are preferred.

The above-mentioned antimony compound and phosphorous acid or phosphate may be reacted once in a suitable solvent at a temperature of 100 to 200° C. for about 30 minutes to 5 hours. As the solvent used in this case, glycols are preferable, and among them, it is preferable to use a glycol having the same component as the raw material of the polyester because it can be used as it is after the reaction.

The molar ratio of antimony compound to phosphite or phosphate in this reaction can vary over a wide range, but if the amount of phosphite or phosphate is too low,
It tends to be difficult to sufficiently suppress the generation of foreign matter on the spinneret surface due to anti-seven when spinning the resulting polyester, and conversely, if the amount of phosphite or phosphate is too large, foreign matter tends to be generated in the polyester. Therefore, it is preferable to react the phosphite or phosphate at a ratio of 0.1 to 500 mol, particularly preferably 1 to 50 mol, with respect to 1 mol of the antimony compound. The reaction product of the antimony compound and phosphite or phosphate obtained in this way can be used as it is dissolved in the solvent after the reaction, or it can be used after isolation. Alternatively, it may be used after isolation and purification, and then redissolved in a suitable solvent such as glycol.

There is no particular restriction on the amount of the reaction product of the antimony compound and phosphite or phosphate, but
If the amount is too low, a sufficient effect of promoting the polycondensation reaction will not be obtained, and if the amount is too high, the color tone of the resulting polyester will deteriorate, and foreign matter based on the antimony component in the polyester will tend to be generated. As the antimony compound to be used, it is appropriate to use 0.01 to 0.1 mole based on the difunctional carboxylic acid component that is the raw material for polyester.

The reaction product of the antimony compound and phosphite or phosphate may be added at any time before the polycondensation reaction is completed, but between before and immediately after the start of the polycondensation reaction. It is preferable to add it to

There is no need to adopt special conditions for the polycondensation reaction carried out in the presence of the above reaction product, and the glyfur ester of difunctional carbon and/or its low polymer is polycondensed to form a polyester. The conditions adopted at that time will be arbitrarily adopted.

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. Brightener, stabilizer, ultraviolet absorber, ether bond inhibitor.

An agent that facilitates dyeing, a flame retardant, an antistatic agent, etc. may be used.

(Function) Even when the polyester polyester for fibers having the structure of the present invention 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.

(Effect of the invention) When the polyester obtained by the production method of the present invention is melt-spun, the time until bending occurs can be significantly extended, so the spinneret exchange cycle can be extended significantly.
Its industrial effects are 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 an orthocumylphenol medium. The b value and b value representing color tone are values measured using a Hunter type color difference meter, and the higher the (L-b) value, the better the color tone. The spinnability was determined using a spinneret with 30 spinning holes with a diameter of 0.3 mm, and the output amount was a o l.
l 7m, discharge temperature 285°C, winding speed 13-1200@/m for 7 days, the height of foreign matter around the outside of the spinning hole and the occurrence of bending therebetween are shown, and the stretchability is as described above. The undrawn yarn obtained by K was stretched at a stretching temperature of 85°C, a stretching ratio of 3.5 times, and a stretching speed of 110.
The wrap ratio is shown when the film is stretched at 0 m/wm and wound into a 2.5 kg roll (150 denier/3o filament).

Example 1 B) Preparation of catalyst 2 parts of ethylene glycol in a reaction vessel with stirrer.

0.05 parts of 7th monium trioxide and 0.05 parts of calcium hydrogen phosphate. 8 parts of O (equimolar to antimony trioxide) was charged, and the mixture was reacted at 190'C under normal pressure reflux for 2 hours.

(b) Production of polyester 100 parts of dimethyl terephthalate, 7 parts of ethylene glycol
0 parts and 0.02 manganese acetate as transesterification catalyst
The two-part mixture was heated from 14-150°C to 240°C, and the transesterification reaction took place over a period of 4 hours while distilling off the methanol.

Here, the total amount of the catalyst solution obtained in (a) above (0.06 mol ratio relative to dimethyl terephthalate as antimony metal)
and then an ethylene glycol slurry containing 0.020 parts of trimethyl phosphate as a stabilizer and 0.3 parts of titanium dioxide as a matting agent, and then heated to 250°C.
The temperature was raised to 290°C and the polycondensation reaction was carried out for 4 hours under reduced pressure of less than 1g of IHmF [η) 0.64° Softening point 26
A polyethylene terephthalate with a color tone value of 66.8.1) and a value of 4.1 was obtained at 0.7°C.

No bending was observed during the 7-day spinning period of this polymer, and the spinnability was extremely good, and the height of foreign matter on the spinneret surface after 7 days was only 15 μm. Moreover, the wrap ratio during stretching was 0.2, and the stretchability was also extremely good.

Example 2 A catalyst was prepared in the same manner as in Example 1-(a), except that calcium dihydrogen phosphate was used in place of the calcium hydrogen phosphate used in Example 5-(a). The same procedure as in Example 1-(b) was carried out except that the obtained catalyst solution was used as a polycondensation catalyst. of the obtained polymer [
η) o, a 4 , softening point 260.1°C 1 color tone has L value 67.7. The b value was -4.3. No bending was observed during the 7-day spinning period of this polymer, and the spinnability was extremely good, and the height of foreign matter on the spinneret surface after 7 days was only 5 μm. Furthermore, the lapping ratio during stretching was as low as 0.2%, and the stretchability was also extremely good.

Examples 3 to 6 Catalysts were prepared in the same manner as in Example 1-(a), except that the amount of calcium hydrogen phosphate used in Example 1-(a)k was varied as shown in Table 1. Example 1-(
(b) was carried out in the same manner.

Comparative Example 1 Example 1 except that 0.05 part of antimony trioxide was used as a polymerization catalyst instead of the catalyst prepared in Example 1-u).
- (Producted in the same manner as ol. The [da] of the obtained polymer was 0.64. The softening point was 263.0°C. The color tone was L value 67.
．． 4. The b value was 6.4.

Bending occurred frequently during the 7-day spinning period of this polymer, and after 7 days, the height of foreign matter on the spinneret surface reached 70 μm, and the wrap rate during stretching reached 15%.

Example 7 86 parts of terephthalic acid and 39 s of ethylene glycol were placed in a pressure-resistant autoclave and heated from 220°C to 260°C under a pressure of 3 &/d G to esterify while distilling off water over a period of 3 hours. Made me react.

Here, the entire amount of the catalyst solution obtained in exactly the same manner as in Example 1-(a) was added, followed by 0.20 parts of trimethyl phosphate as a stabilizer and 0.3 parts of titanium dioxide as a matting agent. After adding ethylene glycol slurry containing
The polycondensation reaction was carried out for 4 hours under reduced pressure of less than [η]0.
61. Softening point 261.00G, color 11L value 67.0. b
Polyethylene terephthalate with a value of 4.2 was obtained.

No bending was observed during the 7-day spinning period of this polymer, and the spinnability was extremely good, and the height of foreign matter on the spinneret surface after 7 days was only 7 μm. Furthermore, the wrap ratio during stretching was as low as 0.2 inches, and the spinning properties were extremely good.

Comparative Example 2 Example 1- used as a polycondensation catalyst in Example 7
The same procedure as in Example 7 was carried out except that 0.05 part of antimony trioxide was used instead of the catalyst obtained in the same manner as in (a). [η] of the obtained polymer was 0.64. Softening point is 261.1℃, 1 tone & iL value 67.3. The b value was 6.2. During the one-day spinning period of this polymer, bending occurred frequently, and the height of the foreign matter on the spinneret surface reached 60 μm after 7 days.

In addition, the lapping ratio during stretching reached 12% 1C.

Example 8 A catalyst was prepared in the same manner as in Example 1-(a) except that calcium hydrogen phosphite was used in place of the calcium hydrogen phosphate used in Example 1-(a). The same procedure as in Example 1i01 was carried out except that the catalyst solution obtained was used as a polycondensation catalyst. [η) of the obtained polymer
0,64. The softening point is 261.9°C and the L value is 66.6.
The b value was 2.5. No bending was observed during the 7-day spinning period of this polymer, and the spinnability was extremely good.After 7 days, the height of foreign matter on the spinneret surface was only 17μ.Furthermore, the wrap ratio during stretching was 0. The stretchability was as low as 2 inches, and the stretchability was also extremely good.

Claims (4)

[Claims] (1) In producing polyester by polycondensing glycol esters of difunctional carboxylic acids, mainly terephthalic acid, and/or their low polymers in the presence of a catalyst, antimony compounds and phosphites are used as catalysts. Alternatively, a method for producing a polyester for textiles, characterized by using a reaction product obtained by reacting the polyester with a phosphate in advance. (2) The reaction product used as a catalyst is an antimony compound, and the reaction product is 0.1 to 50% per mole of the antimony compound.
The method for producing a polyester for fibers according to claim (1), which is a reaction product with 0 mol of phosphite or phosphate. (3) The method for producing polyester for fibers according to claim 11 or (2), wherein the phosphite or phosphate is an alkali metal salt or an alkaline earth metal salt. (4) The method for producing polyester for fibers according to claim 11 or (2), wherein the antimony compound is an oxide of antimony.