JPS58118823A - Production of polyester - Google Patents

Abstract

PURPOSE:To obtain a polyester excellent in color and heat stability in good efficiency, by adding a small amount of a specified phosphorus compound in the production of a polyester consisting mainly of terephthalic acid and ethylene glycol. CONSTITUTION:The purpose polyester is obtained by mixing (A) terephthalic acid, a dicarboxylic acid component based thereon or an esterifiable derivative thereof, with (B) ethylene glycol or a glycol component based thereon, (C) a phosphorus compound of formula II, wherein R<1> is a 7C or higher alkyl, and R<2> is a 1-4C alkylene, in an amount which satisfies formulaI, wherein P is the mol number of phosphorus atoms per mol of the acid component constituting the polyester, and (D) an ester interchange catalyst and a polycondensation catalyst and reacting the mixture. An example of the compound of formula includes diheptyl hydroxymethylphosphonate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyester with good color tone and thermal stability.

9. Polyester, especially polyethylene terephthalate, is widely used as fibers, films, industrial materials, etc. Industrially, bis(β-hydroxyethyl) is produced by direct esterification or transesterification from terephthalic acid or dimethyl terephthalate and ethylene glycol.
It is produced by a method in which terephthalate (including its low polymers) is obtained and polycondensed in the presence of a catalyst at high temperature and under high vacuum to form a high polymer.

Compounds such as zinc, calcium, and lead are used as transesterification reaction catalysts when producing polyester.

Antimony, titanium, germanium as polycondensation catalysts,
It is well known that compounds such as tin and metal compounds such as cobalt compounds are added as agents to impart a blue tint to polymers, but catalysts and cobalt compounds such as #) also promote decomposition and side reactions. This causes phenomena such as deterioration of the color tone and an increase in the amount of ether bonds and terminal carboxyl groups in the polymer.

It is well known that it is effective to have a phosphorus compound present during the polycondensation reaction in order to suppress such decomposition and side reactions. Usually, phosphoric acid, phosphorous acid, or their esters are used. ing.

It is desirable that phosphorus compounds used for such purposes have the following properties.

■ Improving the thermal stability of polyester during melting.

■ Dissolves uniformly in polyester.

■ It does not take away the polycondensation reaction activity of the catalyst.

■ The amount distilled out of the system during the polycondensation reaction is small.

Among the above properties, (1), (2), and (2) are properties that a stabilizer must naturally have, but (2) has not been considered as a problem in the past. However, when considering the yield of phosphorus compounds and the treatment of distillate to prevent pollution, the characteristic (2) cannot be ignored.

The present inventors searched for phosphorus compounds with desirable properties such as those described above, and found that certain phosphonic acid esters have good properties.

We have arrived at the present invention.

That is, in the present invention, when producing polyester from terephthalic acid or a bifunctional carboxylic acid containing terephthalic acid as a main component, or an ester-forming derivative thereof, and ethylene glycol or a glycol containing terephthalic acid as a main component,
General formula (wherein R1 is an alkyl group of 07 or more.

R2 is a C-C4 alkylene group. ) is a method for producing polyester characterized by adding a phosphorus compound represented by the following formula in an amount satisfying the 9th formula.

α2 ,
Examples include dioctyl hydroxymethylphosphonate, dinonyl 2-hydroxyethylphosphonate, dioctyl 4-hydroxybutylphosphonate, and dilauryl 2-hydroxyethylphosphonate.

The phosphorus compound may be added at any time up to the beginning of the polycondensation reaction, and it is convenient to use it as an ethylene glycol solution.

As mentioned above, when producing polyester, in most cases one or more of compounds such as zinc, calcium, lead, antimony, titanium, germanium, tin, etc. or 211 or more compounds are used as a transesterification type 1 condensation catalyst, and blue tinting is used as a type 1 condensation catalyst. Cobalt compounds are present as agents.

Here, the zinc compound includes zinc formate, zinc acetate, zinc chloride, zinc acetylacetonate, etc. 9 Usually, the zinc atom is 0.5 x 10' per mole of the raw acid component.
~10X10'% is used.

Calcium hydroxide is a calcium compound.

Calcium acetate, calcium chloride, calcium acetylacetonate, etc. are usually used in amounts of 1 x 10 to 10 x 10 -' calcium atoms per mole of raw acid component.
Used in molar quantities.

Lead compounds include lead formate, lead acetate, lead acetylacetonate, etc. 1 Usually, about 1 x 104 to 10 x 10' moles of lead atoms are used per mole of the acid component.

Antimony trioxide is an antimony compound.

Antimony trichloride, antimony acetate, antimony glycolate, etc. are used as antimony atoms.
About ×10 to 10×10' mole is used.

Titanium tetramethoxide is a titanium compound.

Titanium tetraethoxide, titanium tetrane propoxide. Titanium alkoxides such as titanium-n-butoxide, titanium salicylic acid salts, and titanium salts of therideraldehyde.

Chelate compounds such as acetylacetone titanium salts, succinates, oxysectates, etc., or dimethyldichlorotitanium, di-π-cyclopentadienyltitanium,
Di-cyclopentadienyl diquar titanium, Di-cyclopentadienylcarbonyl titanium*')) f-g-cyclopentadienyl titanium, C-cyclopentadienyl-S-allyl titanium An organic titanium compound of 0.00% as titanium atoms per mole of the raw acid component is prepared. 1 x 10-' to 5 x 10'' molar 11 degrees are used.

Germanium compounds include germanium dioxide, germanium tetraethoxide, germanium-n-
Germanium alkoxides such as butoxide, methylgermane, ethylgermane.

Organic germanium compounds such as dimethylgermane, trimethylgermanium methoxide, dimethylgermanium diacetate, and tri-n-butylgermanium acetate are commonly used.

1 x 1 germanium atom per mole of raw acid component
0 to 10X10' molar 11i degree is used.

As the tin compound, di-n-butyltin diacetate is used from the viewpoint of solubility in the glycolya reaction system.

)! Organotin compounds such as J-n-butyltin acetate, tri-n-butyltin chloride, bis(tri-n-butyltin) oxide, dimethyltin maleate, and di-n-butyltin maleate are preferred. Usually, 1 mole of the raw acid component is used. On the other hand, as a tin atom α2X10'~5X
Approximately 10'mol is added.

Cobalt compounds include cobalt formate, cobalt acetate,
Examples include cobalt chloride, cobalt carbonate, and cobalt acetylacetone. Usually, about 5x10 to 10x10'' moles of cobalt atoms are used per 1 mole of the acid component.

By the way, 1. The phosphorus compound of the present invention has the effect of emphasizing the effect of the cobalt compound compared to general phosphorus compounds such as phosphate ester and phosphite ester. Addition of cobalt compounds to season the polymer also has the significant advantage that relatively small amounts of cobalt compounds can be used.

Note that the amount of the phosphorus compound added is α per 1 mole of the raw acid component.
If the amount is less than 2x10 mol, the effect of improving the thermal stability of polyester is insufficient;
If it is added in an amount exceeding a molar amount, it will inhibit the activity of the polycondensation catalyst and result in the formation of insoluble matter in the polymer, which is not preferable.

In addition, the phosphorus compound which becomes 9% openness publication i851-154787 is 500-11 as a phosphorus atom in polyester.
A method for producing flame-retardant polyester by adding 0,000 pp of polyester is described. However, the amount of the phosphorus compound to be added in this case is 51.times.10 to 621.times.10@-' mol/mol of the acid component (in the case of polyethylene terephthalate), which is completely different from the scope of the present invention.

In addition, in the disclosed example of the phosphorus compound, R, R, and ' are not only the lower alkyl group of the isobutyl group 1, but also an aryl group, an aralkyl group, and a -cyclohexyl group. No specific example is given. As described above, the present invention and the invention of Japanese Patent Application Laid-open No. 851-134787 have their objectives and configurations.

The effects are completely different.

The method of the present invention uses not only polyethylene terephthalate but also isophthalic acid, P-oxybenzoic acid,
It can also be applied to the production of polyesters having copolymerized components such as 5-sodium sulfoisophthalic acid, adipic acid, diethylene glycol, propylene glycol, 1,4-cyclohexane dimetatool, trimellidic acid, and pentaerythritol.

Further, additives such as color tone modifiers such as dyes and pigments such as carbon black in titanium dioxide may be present together.

In the examples, the intrinsic viscosity of the polymer was measured at a temperature of 20°C using an equal weight mixture of phenol and tetrachloroethane as a solvent.
The value is adjusted in °C.

Regarding the color tone, the obtained polymer is molded into granules and 1
After incubation at 50°C ± 2°C for 1 hour, a zero color difference meter was used.
, the b value was determined. L value lightness (the larger the value, the brighter)
, & value is red, hue of edge thread (+ means reddish, - company-like), b
lia yellow, representing the hue of fruits and vegetables (10: yellowish, -: bluish). As for the color tone of the polymer, the larger the L value, the more the a value is 0.
The closer it is.

Furthermore, if the b value is extremely small, the smaller the b value, the better.

The diethylene glycol component content in the polymer is determined by quantifying ethylene glycol and diethylene glycol by gas chromatography after alkali hydrolysis of the polymer.
Mol% of diethylene glycol to total glycol
(denoted as DEG-) is a friend.

The carboxyl group content in the polymer was measured using the so-called Paul method described in Analytical Cumistry 26 @ p. 1614 (1954), and was determined by the number of carboxyl group equivalents per ton of polymer (C!O).
OH).

The phosphorus content in the polymer is determined after wet decomposition of the polymer.
Colorimetric determination was carried out using the molybdenum glue method and expressed as the ratio of the phosphorus content (residual amount of phosphorus) in the polymer to the amount added, that is, the residual phosphorus rate.

Example 1 A slurry of terephthalic acid and ethylene glycol (ethylene glycol/terephthalic acid ratio 1.5) was continuously supplied to an esterification reactor in which bis(β-hydroxyethyl) terephthalate and its oligomer were present for a long time. ,
The esterification reaction was carried out at 250° C. under normal pressure for a residence time of 6 hours, and an esterified product with a reaction rate of 96-1 was continuously obtained. To this O esterification product, 2 x 10 mol of antimony trioxide, 1 x 10 mol of cobalt acetate, and 5 x 10 mol of dilauryl 2-hydroxyethylphosphonate were added as a catalyst per mol of the acid component, and the mixture was heated under reduced pressure in a glass polymerization tube. Finally, polycondensation was carried out at α1swHg and 285°C for 2 hours.

The obtained polymer has [ma]=073. L value=71.5°a value=-α6. b value = -2,4, C00H = 11.
6, DEG%-gl, 7. The phosphorus residual rate was 87-.

Comparative Example 1 Polymerization was carried out under the same conditions as in Example 1 except that the phosphorus compound was not added.

The obtained polymer has [ma]=α72. L value = 71.5°a value = -Q, 8. tt value = 1. s, C0OH=
22.6, DEG% = 1.8. And 5J!
Compared to the sample of Example 1, the b value is poor (and C00B is increased, indicating that decomposition is progressing.

Comparative Example 2 Comparative Example 2 was carried out under the same conditions as in Example 1 except that 5×10' mol of trimethyl phosphate was added as a phosphorus compound.

The obtained polymer had [ma]=0.72. L value=71.0
゜A value = - (17, b value = -0, 5, 0OOH = 1
i5, DKG1=1.7, and the b value was worse than the result of Example 1.

In addition, the phosphorus residual rate was as low as 52-.

Examples 2 to 8 and Comparative Examples 5 to 4 Example 1 was carried out under the same conditions as in Example 1, except that dioctyl hydroxymethylphosphonate was used as the phosphorus compound and the amount added was changed as shown in the table below. If the amount of phosphorus compound added is insufficient, the value will be large,
It can be seen that the amount of COOH increases, the thermal stability is poor, and when the amount of the phosphorus compound added is too large, the polymerization activity is inhibited.

In addition, in the case of Comparative Example 4, unlike the other examples, the polymer was cloudy, which was not preferable.

1 mol of dimethyl terephthalate, 2 mol of ethylene glycol
1.5 x 10' moles of zinc acetate were placed in a glass flask equipped with a fractionating tube, and heated from 180°C to 230°C under normal pressure.
The temperature was gradually raised to 100%, and the mixture was heated for 5 hours until the distillation of methanol was completed.

This transesterified product was transferred to a glass polymerization tube and 2 liters
Germanium Iride 2 x 10 mol, cobalt chloride 1 x 1
0 mol, dioctyl hydroxymethylphosphonate 5x
Add 10 moles and gradually reduce the pressure until α1
Polycondensation was carried out at mHg and 275°C for 2 hours.

The obtained polymer has [ma]=α75. L value = 72.2
.

a value; -α7. b value = -1, 1, cooH = 1[L5
: DEGI$ = 1.9.

Patent applicant Nihon Ester Co., Ltd. Surrogate child Yuzo Tama

Claims (1)

[Claims] +11 terephthalic acid or a bifunctional V-boxylic acid containing this as a main component, or an ester V-forming derivative thereof, and ethylene glyco-V or a glyco-based composition containing ethylene glyco-V or terephthalic acid as a main component.
When producing polyester from V. Production of polyester characterized by adding a phosphorus compound represented by the general formula % formula % (in the formula, R1 is an alkyl V group of 07 or more; R2 is an alkylene group of C1 to C4) in an amount satisfying the 9th formula. Method. α2 X 10-'≦CP)≦20
Number of moles of phosphorus atoms t-*waC)