JPS6034568B2 - Polyester manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyester, particularly to a method for producing aromatic polyester having a high softening point and good color tone.

Aromatic polyester, whose main components are difunctional aromatic carboxylic acid and glycol, has excellent mechanical, physical, and chemical properties, so it is widely used in fibers, films, and other molded products. There is.

Among aromatic polyesters, polyesters containing terephthalic acid as the main brewing component and ethylene glycol, tetramethylene glycol, hexamethylene glycol or cyclohexane-1,4-dimethylol as the main glycol component are particularly important. Such polyester, particularly polyethylene terephthalate, is produced by heating ethylene glycol ester of terephthalic acid and/or its low polymer under reduced pressure to cause a polycondensation reaction.

This military condensation reaction can proceed smoothly and produce commercially valuable products only by using a catalyst, and the reaction rate and speed depend on the type of catalyst used.
The quality of the resulting product is greatly affected. BACKGROUND ART Titanium compounds such as titanium tetrabutoxide have been known to have excellent polycondensation catalytic ability.

However, when such a titanium compound is used, the resulting polyester tends to be yellowish, and especially when used in such an amount that industrial production speed is limited, the resulting polyester exhibits a marked yellow color and also has a lower softening point. .
Several methods have been proposed for preventing coloring when such titanium compounds are used. That is, Special Publick No. 48-22
Japanese Patent Publication No. 26597 discloses a method using titanium hydride, and Japanese Patent Publication No. 47-26597 discloses a method using Q-titanic acid. However, in the former method, titanium hydride powder is not easily produced, and in the latter method, the titanic acid is easily deteriorated, making it difficult to store and handle. It's not an appropriate method. Moreover, these methods only yield polyesters with low softening points. This drawback causes the generation of scum during processing of molded products, especially fibers, films, etc., and staining of the resulting products. As a result of intensive research into a method for polycondensing polyester with a high softening point and good color tone using a titanium compound, the present inventor found that
It has been found that the above object can be achieved by using a reaction product obtained by reacting titanium tetrabutoxide and phthalic acid as a polycondensation catalyst.

The present invention was completed as a result of further intensive research based on this knowledge. That is, the present invention relates to the production of polyester by subjecting at least one type of difunctional aromatic carboxylic acid glycose ester and/or its low polymer to a condensation reaction in the presence of a polycondensation catalyst. Ti(OR)4 [wherein R represents an alkyl group].

] This is a method for producing polyester, characterized in that a reaction product obtained by reacting a titanium compound represented by the following with phthalic acid or its anhydride in advance is used.

The glycose ester of difunctional aromatic carboxylic acid used in the present invention may be produced by any method.

It is usually produced by subjecting a bifunctional aromatic carboxylic acid or its ester-forming derivative to a heating reaction with glycol or its ester-forming ghost conductor. The Ninomiyadate aromatic carboxylic acid used here is mainly terephthalic acid, and its ester-forming derivative has 1 carbon number.
-4 alkyl esters, phenyl esters, etc. are preferably used. In addition, difunctional aromatic carboxylic acids other than terephthalic acid, such as isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenylmethane dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxyethane dicarboxylic acid, It may be 3-hydroxyethoxybenzoic acid, etc., or a part of the main component bifunctional aromatic carboxylic acid may be substituted with other bifunctional aromatic carboxylic acids and/or such as sebacic acid, adipic acid, etc. It may be replaced with a difunctional aliphatic carboxylic acid such as abalic acid, a difunctional alicyclic carboxylic acid such as 1,4-cyclohexanedicarboxylic acid, or an ester-forming derivative thereof. Glycol mainly refers to ethylene glycol, and as its ester-forming derivative, ethylene oxide is particularly preferably used.

Other aliphatic and alicyclic glycols such as tetramethylene glycol, trimethylene glycol, and cyclohexane-1,4-dimethanol may also be used. A method for producing a glycol ester and/or a low polymer thereof from such a brewing component and a glycol component is as follows: Generally employed are methods of directly esterifying terephthalic acid and ethylene glycol, transesterifying lower alkyl esters of terephthalic acid and ethylene glycol, or adding ethylene oxide to terephthalic acid. .

Although any catalyst can be used in these reactions, it is preferable to select and use a catalyst that does not adversely affect the color tone, taking into account the purpose of the present invention. In particular, when employing a transesterification method, the reaction product of phthalic acid or its anhydride used as a polycondensation catalyst in the present invention and a titanium compound can also be used as a transesterification catalyst, and it is preferable to do so. That's true. The polycondensation catalyst used in the method of the present invention has the following general formula Ti(OR)
4 [In the formula, R is an alkyl group, particularly preferably a propyl group or a butyl group.

] is a reaction product of a titanium compound (preferably titanium tetraproboxide or titanium tetrabutoxide) and phthalic acid or its anhydride. dissolve,
A titanium compound may be added dropwise to this, and the reaction may be carried out at a temperature of 0° C. to 20,000° C. for about 30 minutes or more.

The reaction pressure at this time is not particularly limited, and normal pressure is sufficient.
Note that any solvent that can dissolve part or all of phthalic acid or its anhydride can be used, but ethanol, ethylene glycol, benzene, etc. are particularly preferred.
Although the molar ratio of the titanium compound and phthalic acid or its anhydride in this reaction can vary over a wide range, too much titanium compound tends to adversely affect the color tone and softening point of the resulting polyester; If the amount of titanium compound is too small, the military condensation reaction tends to be difficult to proceed sufficiently, so it is preferable to use phthalic acid or its anhydride at a ratio of 1/2 to 21/2 mol per 1 mol of titanium compound. . The reaction product of the titanium compound and phthalic acid or its hot water (hereinafter referred to as titanium phthalate) obtained in this way may be used as it is, or it may be used after being re-purified using Accent, etc. .

There is no need to limit the amount used, but if it is too small, a sufficient military condensation reaction rate cannot be obtained, and if it is too large, the resulting polyester tends to turn yellow, so it is usually used as a raw material for polyester. 0.001~ in terms of titanium atom for the difunctional carboxylic acid component
0.5 mol%, preferably 0.005-0.02 mol%
It is. Although it can be added at any time before the phthalic acid reaction is completed, it is preferably added between before and immediately after the start of the polycondensation reaction. Particularly when it is also used as a transesterification catalyst, it is preferable to add the above amount between before and just before the start of the transesterification reaction. Note that other phthalic acid catalysts such as antimony compounds, germanium compounds, etc. can also be used in combination without departing from the purpose of the present invention. When isophthalic acid or terephthalic acid similar to phthalic acid is used instead of phthalic acid, that is, the reaction product of isophthalic acid and the titanium compound or the reaction product of terephthalic acid and the titanium compound is used as a polycondensation catalyst. In this case, the polyester obtained becomes extremely yellow and has a low softening point, making it impossible to achieve the object of the present invention. Although the reason for this is not clear, it is thought that the coordination state of the bond is different between the titanium compound and phthalic acid (or its anhydride), isophthalic acid, and terephthalic acid. The polycondensation reaction in the present invention does not require special conditions;
Conditions employed when glycose esters of difunctional carboxylic acids and/or their low polymers are subjected to a polymerization reaction to form polyesters may be arbitrarily employed.

In the case of polyester terephthalate, the glycol generated by heating the ethylene glycol ester of terephthalic acid and/or its low polymer to which the above amount of titanium phthalate has been added under reduced pressure to a temperature above the melting point and below 300 qo is generally used. A method is adopted in which a polycondensation reaction is caused by distillation. Furthermore, when titanium phthalate is used as a transesterification catalyst, there is no need to adopt special conditions for the transesterification reaction. (lower alkyl ester of terephthalic acid and ethylene glycol or a mixture of these and their reaction products) at normal pressure or under slight pressure (usually 10 k9 /
After the transesterification reaction is carried out by heating to 150 to 250q0 under slightly reduced pressure (usually up to about 50 Hg) and distilling off the generated alcohol, the polycondensation reaction is then completed. . In carrying out the present invention, a monofunctional compound such as penzylbenzoic acid, phenol sulfonate, r-hydroxypropanesulfonate, etc. may be bonded to the terminal end of the obtained polyester. A trifunctional or higher functional compound may be copolymerized in an amount that does not substantially cause the polyester to lose its thermoplasticity. Furthermore, optional additives such as colorants, matting agents, optical brighteners, stabilizers, ultraviolet absorbers, ether bond inhibitors, beam-enhancing agents, flame retardants, antistatic agents, etc. are added as necessary. may be used.

The present invention will be explained in further detail by giving examples below.

In the examples, parts are parts by weight, and 〔〕 is the intrinsic viscosity determined from the viscosity measured at 360 using orthochlorophenol as a solvent. The color tone is 200% when the polymer is placed in a nitrogen stream.
After crystallization by heat treatment at OO for 2 minutes, the surface was measured using a Color Machine CM-20 model (manufactured by Color Machine Co., Ltd.) and the obtained L value and b value were shown. The L value indicates brightness, and the larger the number, the higher the brightness, and the b value indicates that the value is (10).
The larger it is toward the (1) side, the greater the degree of yellow, and the greater it is toward the (1) side, the greater the degree of blue. Softening point is measured by the ventilation method. Example 1 and Comparative Example 1 (After dissolving 0.6 parts of phthalic acid in 2.5 parts of ethanol, 0.64 parts of titanium tetrabutoxide (1'2 times mole relative to phthalic acid) was added dropwise. Under normal pressure in air 80
The reaction temperature was maintained at 0.0000 for 60 minutes to generate reaction heat.

After the reaction heat, it was cooled to room temperature, 15 parts of acetone was added, and the precipitate was mixed into No. It was filtered using a 5C oven paper and dried at 10,000 for 2 hours. The titanium content of the obtained precipitate was 12
．． It was 5% by weight. {0} Synthesis of polyester 97 parts of dimethyl terephthalate, 64 parts of ethylene glycol, and 0.18 parts of the precipitate obtained in {a} above were reacted using a lump punch, a rectification column, and a methanol condenser. The mixture was charged into a vessel and heated from 14°C to 230°C to carry out a transesterification reaction while distilling methanol produced as a result of the reaction out of the system.

Three hours after the start of the reaction, the internal salt reached 23,000, and 32 fat B
of methanol was distilled out. Here, 0.18 parts of trimethyl phosphate as a stabilizer and 4.85 parts of titanium dioxide as a matting agent were added, and the reaction mixture was then transferred to a reactor equipped with a base mill and an ethylene glycol distillation condenser. The polycondensation reaction was carried out while gradually raising the temperature from 23,000 to 28,500 and lowering the pressure from normal pressure to a high vacuum of 1 square Hg.

A polymer of 0.649 was also obtained in a total polycondensation reaction time of 3 hours and 30 minutes. The softening point of this polymer is 262.000
The color tone had an L value of 81.5 and a b value of 3.0. For comparison, the reaction was carried out in the same manner as in {0} above, except that 0.17 parts of titanium tetrabutoxide was used instead of the precipitate obtained in {a} above.

The [sword] of the obtained polymer is 0.600, and the color tone is L value 7.
80 b value was 10.5 and softening point was 258.3q○.
Example 2 97 parts of dimethyl terephthalate and 64 parts of ethylene glycol were added to the transesterification reactor used in Example 1-'o}.
The mixture was charged with 0.36 parts of manganese acetate and heated from 140°C to 230°C to carry out a transesterification reaction while distilling off methanol produced as a result of the reaction.

2 hours after the start of the reaction, the internal temperature was 230 oo
32 parts of methanol was distilled out. Here, 0.238 parts of trimethyl phosphate as a stabilizer and 4.85 parts of titanium dioxide as a matting agent were added, and further 0.18 parts of the precipitate obtained in Example-[A] were added. A polycondensation reaction was carried out in the same manner as in o-.

The obtained polymer has a thickness of 0.640 and a softening point of 262.
．． 100, and the color tone was L value 82.8 and b value 3.1.
Example 3 The reaction was carried out in the same manner as in Example 1-(i), except that the molar ratio of phthalic acid to titanium tetrabutoxide' was varied as shown in Table 1 in Example 1-(i), and the respective precipitates were The obtained products were reacted in the same manner as in Example 11{o} using 0.18 parts of each precipitate.

The results were as shown in Table 1. Table 1 Example 4 In Example 2, the reaction was carried out in the same manner as in Example 2, except that 0.02% of sodium methylate was added at the same time as the precipitate obtained in Example 1-{i. I forced it.

The resulting polymer had a softening point of 0.64 mm and 262 mm.
5qo, and the color tone was L value 82.5 and b value 4.0. Example 5 Example 2 except that 0.76 parts of magnesium acetate was used instead of manganese acetate in Example 2, and 0.426 parts of orthophosphoric acid was used instead of trimethyl phosphate.
I reacted in the same way.

The obtained polymer had a [sword] of 0.65 and a softening point of 262.
1oo, and the color tone was L value 83.2 and b value 2.5. Example 6 and Comparative Examples 2 and 3 Instead of the phthalic acid used in Example 1-1, various aromatic dicarboxylic acids of the second notation were used in an amount twice that of titanium tetrabutoxide. The precipitates were obtained in the same manner as in Example 1-A, and the reaction was carried out in the same manner as in Example 2, except that 0.18 parts of each of these precipitates was used.

The results were as shown in Table 2. Table 2 Example 7 Titanium tetrabutoxide used in Example 1-{i' was replaced with titanium tetrabutoxide.

The titanium content was 21.0% in the same manner as in Example 11', except that 1.06 parts of poxide (1 times the mole relative to phthalic acid) was used. A precipitate with a temperature of Marugame ℃ was obtained. A reaction was carried out in the same manner as in Example 2 except that 0.1 of this precipitate was used.

Claims (1)

[Scope of Claims] 1. When producing a polyester by subjecting at least one kind of difunctional aromatic carboxylic acid glycose ester and/or low polymer to a polycondensation reaction in the presence of a polycondensation catalyst, the following polycondensation catalysts may be used: General formula Ti(OR)_4 [wherein, R represents an alkyl group]. A method for producing polyester, which comprises using a reaction product obtained by reacting a titanium compound represented by the following formula with phthalic acid or its anhydride in advance. 2 The polycondensation catalyst has the following general formula Ti(OR)_4 [wherein, R represents an alkyl group]. ] Claim 1, which is a reaction product obtained by previously reacting the titanium compound represented by the following formula with phthalic acid or its anhydride in a ratio of 1/2 to 21/2 mol per 1 mol of the titanium compound. The method for producing polyester described in Section 1. 3 The titanium compound which is one of the reaction components of the polycondensation catalyst has the following general formula Ti(OR')_4 [wherein R' represents an alkyl group having 3 or 4 carbon atoms. ] Claim 1 is a titanium compound represented by
The method for producing polyester according to item 1 or 2. 4. A method for producing a polyester in which the glycose ester of a difunctional aromatic carboxylic acid is terephthalic acid. 5. The method for producing a polyester according to any one of claims 1 to 3, wherein the glycose ester of a difunctional aromatic carboxylic acid is a tetramethylene glycol ester of terephthalic acid.