JPH01197523A - Preparation of polyester - Google Patents

Abstract

PURPOSE:To improve spinnability and whiteness, by adding a predetermined amt. of a metal sulfonate and a quat. phosphonium sulfonate at an optional stage before the completion of reaction in heating and reacting a bifunctional carboxylic acid, etc., and an alkylene glycol. CONSTITUTION:0.005-0.495% metal sulfonate of formula I (wherein Z1 is an arom. group or an aliph. group; A1 is an ester-forming functional group; A2 is A1 or H; M is a metal; m is a positive integer) and 0.005-0.495% quat. phosphonium sulfonate of formula II (wherein R1-4 are each alkyl or an aryl; n is m) are added in such a way that the sum is 0.01-0.5%, at an optional stage before the completion of reaction in heating and reacting a bifunctional carboxyllic acid, the main component of which is terephthalic acid or its ester- forming deriv. (e.g., dimethyl terephthalate) and at least one alkylene glycol (e.g., ethylene glycol), if necessary, in the presence of 0.01-0.1% (mol% based on the carboxylic acid, the same applies hereinbelow) ester exchange catalyst such as manganese acetate and 0.003-0.1% polycondensation catalyst such as an org. Ti compd.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing polyester, and more particularly to a method for producing polyester having excellent color tone and moldability.

<Prior art> Polyester, especially polyethylene terephthalate, has many excellent properties and is used for various purposes, especially for textiles,
Widely used for films and other molded products.

Such polyesters are usually produced by esterifying terephthalic acid and ethylene glycol, by subjecting dialkyl terephthalate and ethylene glycol to a Nisdell exchange reaction, or by reacting terephthalic acid and ethylene oxide to form a glycol ester of terephthalic acid and It is produced by producing a low polymer thereof and then heating the product under reduced pressure to cause a polycondensation reaction until a predetermined degree of polymerization is achieved.

The polyester thus obtained can be extruded in a molten state into a fiber or film form through small holes (spinning holes) or slits, and then stretched or melt-molded such as injection molding to produce plastic parts. , has been put into practical use as hollow molded bodies such as bottle containers.

The reaction of the above polyester can proceed smoothly by using a catalyst, but the reaction still requires high temperature, and furthermore, because it is kept molten during molding, it tends to decompose and become colored during the reaction and molding. is strong.

In order to prevent this decomposition and discoloration, various phosphorus compounds such as phosphoric acid, phosphorous acid, alkyl esters and aryl esters thereof, etc. are generally used as stabilizers. However, even if such a phosphorus compound is used, coloring cannot be sufficiently prevented, and a coloring agent is usually used. Cobalt acetate, cobalt chloride I~ as a coloring agent
, cobalt compounds such as cobalt benzoate are widely used, and in some cases, nickel compounds, @compounds, etc. are also used.

Although it is possible to improve the color tone of polyester by using such color toners, there are serious drawbacks. In other words, the metal used as a coloring agent reacts with the phosphorus compound used as a stabilizer or reacts with the catalyst, producing insoluble foreign matter in the polyester, which causes various troubles during the molding process, especially This causes the pack pressure to rise abnormally during extrusion.

<Problems to be Solved by the Invention> The present inventors have arrived at the present invention as a result of intensive studies to eliminate the above-mentioned drawbacks caused by the color adjusting agent and to improve the color tone of the obtained polyester.

<Structure of the Invention> That is, the present invention provides a method for producing a polyester by subjecting a difunctional carboxylic acid, mainly terephthalic acid, or an ester-forming derivative thereof and at least one alkylene glycol to a heating reaction, before the reaction is completed. 0.005 to 0 for the difunctional carboxylic acid component at any stage of
．． 495 mol % of the following - maximum (I) Al - Zl - A2...
... (I) ■ (S03M)m (wherein, Zl is an aromatic group or aliphatic group, AI is an ester-forming functional group, A2 is the same or different ester-forming functional group or hydrogen atom as A1, 0.005 to 0.49 for the sulfonic acid metal salt compound and the bifunctional carboxylic acid component represented by M is a metal and m is a positive integer.
5 mol % of the following - maximum (n) AI Zs -A2 -- (ff) (
In the formula, Zl is an aromatic group or an aliphatic group, A1 is an ester-forming functional group, A2 is the same or different ester-forming functional group or hydrogen atom, R1゜R2, R3 and R4
are the same or different groups selected from the group consisting of alkyl groups and aryl groups, and n represents a positive integer).
The total amount of the sulfonic acid metal salt and the sulfonic acid quaternary phosphonium salt is 0.0 with respect to the bifunctional carboxylic acid component.
This is a method for producing polyester, characterized in that it is added in an amount of 1 to 0.5 mol%.

The polyester in the present invention is a polyester having terephthalic acid as the main acid component and at least one type of glycol, preferably at least one alkylene glycol selected from ethylene glycol, trimethylene glycol, and tetramethylene glycol as the main glycol component. The main target is

It may also be a polyester in which part of the terephthalic acid component is replaced with another difunctional carboxylic acid component, and/
Alternatively, it may be a polyester in which part of the glycol component is replaced with the above-mentioned glycol or other diol component other than the main component.

Examples of the difunctional carboxylic acids other than terephthalic acid used here include isophthalic acid, naphthalene dicarboxylic acid, and diphenyl dicarboxylic acid.

Aromatic, aliphatic, and alicyclic difunctional carboxylic acids such as diphenoxyethanedicarboxylic acid, β-hydroxyethoxybenzoic acid, p-oxybenzoic acid, adipic acid, sebacin a, and 1,4-cyclohexanedicarboxylic acid. I can give it to you.

Examples of diol compounds other than the above-mentioned glycols include cyclohexane-1,4-dimetatool, neopentyl glycol, and bisphenol A.

Examples include aliphatic, alicyclic, and aromatic diol compounds such as bisphenol S, and polyoxyalkylene glycols.

Furthermore, polycarboxylic acids such as trimellitic acid and pyromellitic acid, polyols such as glycerin, trimethylolpropane, and -pentaerythritol can be used as long as the polyester is substantially linear.

Such polyesters can be synthesized by any method6
For example, in the case of polyethylene terephthalate, usually terephthalic acid and ethylene glycol are directly esterified, a lower alkyl ester of terephthalic acid such as dimethyl terephthalate is transesterified with ethylene glycol, or terephthalic acid and ethylene glycol are transesterified. The first stage reaction is to react with terephthalic acid to produce a glycol ester and/or its low polymer, and the first stage reaction product is heated under reduced pressure until the desired degree of polymerization is achieved. It is produced by a second step of polycondensation reaction.

Any catalyst can be used in these reactions as necessary. Among these, when adopting the transesterification method, calcium compounds, manganese compounds, magnesium compounds, zinc compounds, cobalt compounds, etc. are preferable as transesterification catalysts, and these may be used alone or in combination of two or more, and the amount used is is preferably 0.01 to 0.1 mol % based on the bifunctional carboxylic acid component used as the polyester raw material.

Also, antimony compounds are used as polycondensation catalysts.

Titanium compounds and germanium compounds are preferred, and organic titanium compounds, especially reaction products obtained by reacting titanium tetraalkoxide and trimellitic anhydride in ethylene glycol, are preferred. It can be obtained by the method described in Japanese Patent No. 53-45395. These polycondensation catalysts may be used alone or in combination, and the amount used is preferably 0.003 to 0.1 mol % based on the bifunctional carboxylic acid component.

In the present invention, the sulfonic acid metal salt compound and the sulfonic acid quaternary phosphonime salt compound are added at any stage before the reaction for producing the polyester is completed.

The sulfonic acid metal compound used here is as follows - maximum (I
).

AI -Zl -A2 ......(I)(
S03M)m In the formula, zl represents an aromatic group or an aliphatic group, and aAl, which is preferably an aromatic group, represents an ester-forming functional group, and a specific example is 0 0 Q(E-CH
2-)-OH.

0-fCH2te'+0(CH2)b÷,OH1(18L
, R' is a lower alkyl group or phenyl group, a and d are 1
b is an integer greater than or equal to 2), etc. A2 represents the same or different ester-forming functional group or hydrogen atom as A1, and 6M, which is preferably an ester-forming functional group, represents a metal atom;
Among them, Na, Li, Ti, Ca, Zn, Mg, M
0m, preferably n, is a positive integer.

Preferred examples of the sulfonic acid metal salt compounds represented by maximum (I) above include 5-sodium dimethyl sulfoisophthalate, 5-lithium dimethyl sulfoisophthalate, and 5-sodium sulfoisophthalate bis(p-hydroxyethyl) ester. , 5-lithium sulfoisophthalate bis(ρ-hydroxyethyl) Nisdel, and the like.

Nakadera 5-sodium sulfoinphthalate bis(p-
Hydroxyethyl) esters are preferred.

In addition, the sulfonic acid quaternary phosphonium salt compound to be used together with the above sulfonic acid metal salt compound is as follows - maximum (I
Represented by [).

A, -Z, -A2 (II
)(so 30 P■ R, R21, R4) n In the formula, Zl represents an aromatic group or an aliphatic group, and among them, an aromatic group is preferable, AI represents an ester-forming functional group,
A specific example is 0 0.

fc) [2-5t a OH.

-〇 Ito CH2 Rahi 6--I child 0 < CH
2) b 10d Oto■.

-C-← o (CH2) b 1d 01
1 ((8L, R' is a lower alkyl group or phenyl group, a
and d is an integer of 1 or more, b is an integer of 2 or more), etc. A2 represents the same or different ester-forming functional group or hydrogen atom as A1, and is preferably an ester-forming functional group, R1, R2
, R3 and R4 are the same or different groups selected from alkyl groups and aryl groups, and n is a positive integer.

Such sulfonic acid quaternary phosphonium salt compounds are generally the above-mentioned sulfonic acid quaternary phosphonium salts that can be easily synthesized by the reaction of the corresponding sulfonic acid and phosphines or the reaction of the corresponding sulfonic acid metal salt and quaternary phosphonium halides. Preferred specific examples of the compound include 3.5-dicarboxybenzenesulfonic acid tetrabutylbosphonium salt, 3.5-dicarboxybenzenesulfonic acid ethyltributylphosphonium salt, 3.5-dicarboxybenzenesulfonic acid tetrabutylbosphonium salt,
．． 5-dicarboxybenzenesulfonic acid benzyltributylphosphonium salt.

3.5-dicarboxybenzenesulfonic acid phenyltributyl phosphonium salt, 3,5. -dicarboxybenzenesulfonic acid detraphenylphosphonium salt, 3.5
-dicarboxybenzenesulfonic acid dithyltriphenylphosphonium salt, 3,5-dicarboxybenzenesulfonic acid butyltriphenylphosphonium salt, 3,5-dicarboxybenzenesulfonic acid benzyltriphenylphosphonium salt, 3,5-dicarboxymethoxy Benzene sulfonic acid tetrabutylphosphonium salt, 3,5. -Dicarpomethoxybenzenesulfonic acid dityltributylphosphonium salt, 3.5-dicarbomethoxybenzenesulfonic acid benzyltributylphosphonium salt, 3.5-dicarbomethoxybenzenesulfonic acid phenyltributylphosphonium salt, 3.5-dicarbomethoxy Benzenesulfonic acid tetraphenylphosphonium salt, 3,5-dicarpomethoxybenzenesulfonic acid ethyltriphenylphosphonium salt, 3,5. -butyl dicarbomethoxybenzenesulfonate l~riphenylphosphonium salt, 3.5
-Dicarbomethoxybenzenesulfonic acid benzyltriphenylphosphonium salt, 3-carboxybenzenesulfonic acid tetrabutylphosphonium salt, 3-carboxybenzenesulfonic acid tetraphenylphosphonium salt, 3-carboxybenzenesulfonic acid tetrabutylphosphonium salt , 3-carbomethoxybenzenesulfonic acid tetraphenylphosphonium salt, 3.5-di(β-hydroxyethoxycarbonyl)benzenesulfonic acid tetrabutylphosphonium salt, 3.5-di(β-hydroxyethoxycarbonyl)benzenesulfonic acid tetra Phenylphosphonium salt.

3-(β-hydroxyethoxycarbonyl)benzenesulfonic acid tetrabutylphosphonium salt, 3-(β-hydroxyethoxycarbonyl)benzenesulfonic acid tetraphenylphosphonium salt, 4-hydroxyethoxybenzenesulfonic acid tetrabutylphosphonium salt, 2.6-
Examples include dicarpoxynaphthalene-4-sulfonic acid tetrabutylphosphonium salt, α-tetrabutylphosphonium sulfosuccinic acid, and the like. The above quaternary phosphonium sulfonic acid salts may be used alone or in combination of two or more.

If the amount of the sulfonic acid metal salt compound and the sulfonic acid quaternary phosphonium salt compound used is too small, the effect of improving the hue of the polyester cannot be obtained; Since the quaternary phosphonium salt is copolymerized, the moldability and physical properties of the polyester are rather deteriorated. Therefore, 0.005 to 0.495 mol% of a sulfonic acid metal salt compound and 0.005 to 0.495 mol% of a sulfonic acid quaternary phosphonium salt compound are added to the bifunctional carboxylic acid used as a raw material for polyester. The amount may be selected and added from within the range and the total amount of the sulfonic acid metal salt compound and the sulfonic acid quaternary phosphonium salt compound is 0.01 to 0.5 mol %.

Additionally, this addition can be done at any time before the polyester production reaction is completed, and it can be added at the same time as other additives used in polyester production, such as catalysts and stabilizers, or it can be added as is. However, they may be added after being dispersed or dissolved in a suitable solvent such as glycol.

<Effects of the Invention> According to the method of the present invention, the obtained polyester contains
Insoluble foreign matter caused by the coloring agent is not generated, and therefore, the increase in pack pressure during the forming process, especially during the spinning process, is small, and spinning can be carried out in a stable state for a long period of time.

Moreover, the produced polyester has an excellent color tone, has little yellowish tinge, exhibits very high white discoloration, and does not discolor during the soil scraping process, making it easy to obtain a product with high commercial value.

In carrying out the present invention, a matting agent such as titanium dioxide, an antistatic agent, a flame retardant, and other additives may be used as necessary.

Nut Glaze Example> The present invention will be described in detail below with reference to Examples. Parts in the examples are parts by weight, and [η] is the intrinsic viscosity determined from the value measured at 30° C. in an orthochlorophenol solvent. The color tone of the polymer was indicated by the L value and b value measured using a Hunter type color difference meter. The larger the L value, the better the whitening, and the smaller the b value, the weaker the yellowness.

Examples 1 to 3 and Comparative Example 1.2 100 parts of dimethyl terephthalate, 70 parts of ethylene glycol, 0.032 parts of manganese acetate, and 5-sodium dimethyl sulfoisophthalate in the amounts shown in Table 1 were added to a transesterification reactor. The temperature was raised from 150°C to 220°C, and the transesterification reaction was carried out while distilling the generated methanol out of the system. Subsequently, a 20% heated ethylene glycol solution of tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate in an amount not shown in Table 1 was added to the obtained product, stirred, and then added as a stabilizer. 0.018 part of trimethyl phosphate was added, and at the same time, expulsion of excess ethylene glycol was started at elevated temperature. After 10 minutes, 0.045 parts of antimony trioxide was added as a polycondensation catalyst, and an ethylene glycol slurry containing 0.3 parts of titanium dioxide was added as a matting agent. Stirring was continued until the temperature reached 240°C. Finished eliminating ethylene glycol.

This reaction product was transferred to a polymerization tank and reacted at normal pressure until the temperature reached 260°C, and then the pressure was reduced from 760++ mHg to 1+nmHg over 1 hour. At the same time, the temperature of the inner bath was raised to 280°C, and the temperature was further increased to 1++ unH (l The polymerization reaction was completed after 2 hours of polymerization under reduced pressure at a polymerization temperature of 280° C. The quality of the obtained polymer is shown in Table 1.

Example 4 350 parts of dimethyl terephthalate, 2 parts of ethylene glycol
24 parts, titanium tetrabutoxide 0.025 parts, 5-
Sodium dimethyl sulfoisophthalate 0.027 part (
A transesterification reaction vessel was charged with 0,005 mol % of terephthalate (dimethyl terephthalate), and transesterification was carried out at 170 to 230°C.

When 230°C + IJ was reached, 0.091 part of 3.5-dicarboxybenzenesulfonic acid tetrabutylphosphonium salt (0.01 mol% to dimethyl terephthalate) was added as a 20% heated ethylene glycol solution and stirred for 20 minutes. Afterwards, the temperature was further raised to 240°C.

Germanium oxide 0.04 when no distillate comes out
7 parts and 0.062 parts of orthophosphoric acid were added thereto, and the mixture was transferred to a polymerization reaction tank. React at normal pressure for about 10 minutes at 260-270°C,
Thereafter, the reaction was carried out at 280° C. under high vacuum (high vacuum of several +++ mtlQ or more) for about 3 hours. Get it! J
7-ノ[77] Cf0.65te Hue L 1iff7
8.9b value was 1.8.

Hisakura example 3 Dimethyl 5-sodium sulfoisophthalate.

The same procedure as Example 4 was carried out except that 3.5-dicarboxybenzenesulfone butylphosphonium salt was not added.

[η] of the resulting polymer was 0.64, and the hue was L value 78.5 and b value 3.5.

Claims (1)

[Claims] (1) When producing a polyester by heating and reacting a difunctional carboxylic acid, mainly terephthalic acid, or its ester-forming derivative, and at least one alkylene glycol, at any stage before the completion of the reaction, 0.005 to 0.495 for functional carboxylic acid component
The following general formula (I) for the amount to be mol% ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(I
) (wherein, Z_1 is an aromatic group or aliphatic group, A_1 is an ester-forming functional group, A_2 is an ester-forming functional group or a hydrogen atom that is the same as or different from A_1, M is a metal, and m is a positive integer. 0.005 to 0.005 to the sulfonic acid metal salt compound represented by ) and the difunctional carboxylic acid component.
The following general formula (II) in an amount of 0.495 mol% ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(II) (In the formula, Z_1 is an aromatic group or aliphatic group, A_1 is Ester-forming functional group, A_2 is the same or different ester-forming functional group or hydrogen atom, R_1, R_2 as A_1
, R_3 and R_4 are the same or different groups selected from the group consisting of alkyl groups and aryl groups, and n represents a positive integer. ) A sulfonic acid quaternary phosphonium salt compound represented by
The total amount of the sulfonic acid metal salt and the sulfonic acid quaternary phosphonium salt is 0.0 with respect to the bifunctional carboxylic acid component.
A method for producing polyester, characterized in that it is added in an amount of 1 to 0.5 mol%.