JPS5943487B2 - Production method of flame retardant copolyester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a flame-retardant copolyester, and more particularly, a polyester such as polyethylene terephthalate is mixed with an arylphosphonic acid or an ester-forming derivative thereof and 2,2-bis(3', 5'-dibromo4'-oxyethoxyphenyl)propane (TBA
The present invention relates to a method for producing a flame-retardant copolyester with good color tone by copolymerizing -EO).

Various methods have been proposed to make polyesters such as polyethylene terephthalate flame retardant, and one of the most effective methods is the synergistic effect of phosphorus and bromine. There is.

Among these methods, the method of directly copolymerizing a phosphorus compound represented by arylphosphonic acid or its ester and a bromine compound represented by TBA-EO into polyester is such that the flame retardant is uniformly bonded to the polyester, and the flame retardant is bonded uniformly into the polyester, and then This is an excellent method as it does not fall off. However, TBA/EO as a bromine-containing monomer has low heat resistance and tends to cause decomposition and coloration at high temperatures during polycondensation of polyester, making it difficult to obtain a copolyester with a sufficiently high polymerization degree and good color tone as a product. It is. Taking this fact into consideration, in Japanese Patent Application Laid-open No. 49-54494, TBA
- EO is reacted with a polyester-forming component at 245°C or lower to form a prepolymer, and then the temperature is raised to 265-350°C to complete polycondensation, and the EO has a hydroxyl value of 170-175 and an acid value of 1 or less. , 5θ of TBA in 50ml of solution
-Use TBA-EO with an APHA of 35 or less in the acetone solution containing EO, use TBA-EO purified by recrystallization from a suitable solvent such as isopropanol, and optionally use a brightening agent. It is considered desirable to add . However, even if such measures are taken, satisfactory results cannot be obtained when a polyester is copolymerized with both arylphosphonic acid or its ester-forming derivative and TBA-EO in an amount that provides sufficient flame retardancy. In view of these circumstances, the inventors of the present invention
As a result of extensive research, we have found that when copolymerizing arylphosphonic acid or its ester and TBA-EO into polyester, the properties of TBA/EO used as raw materials are closely related to the polycondensation reaction rate, degree of polymerization, and color tone of the resulting copolyester. We discovered that there is a relationship and arrived at the present invention.

That is, the present invention provides a copolyester produced from a dicarboxylic acid or an ester-forming derivative thereof, a glycol, an arylphosphonic acid or an ester-forming derivative thereof, and TBA-EO, with a phosphorus content of 0.05 to 0.5% by weight.
, when producing a copolyester with a bromine content x (wt%) of 5 to 15, B≦80, A/B≧(x+10)
It is characterized by using TBA-EO that satisfies /100.

Here, A and B are TBA-EOlO9/methanol 1d1
B indicates the APHA value of a solution with a concentration of 2 in a nitrogen atmosphere.
TBA・EO heat treated at 50°C for 3 hours. A indicates the value for TBA-EO before the heat treatment.

According to the method of the present invention, it is possible to obtain a copolyester having a high degree of polymerization, a good color tone, and a high degree of flame retardancy within a relatively short polycondensation time, which is extremely advantageous industrially.

The present invention will be explained in detail below.

In the present invention, dicarboxylic acids and their ester-forming derivatives include dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenyl ether dicarboxylic acid, and diphenoxyethane dicarboxylic acid, and their lower alkyl acids. Examples of glycols include esters, and examples of glycols include ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, and polyethylene glycol.

Further, examples of the arylphosphonic acids and ester-forming derivatives thereof used in the present invention include arylphosphonic acids such as phenylphosphonic acid, naphthalenephosphonic acid, and p-tolylphosphonic acid, and their lower alkyl esters and oxyalkyl esters. .

Arylphosphonic acid or its ester-forming derivative needs to be added at a stage before the completion of polycondensation, but when using the transesterification reaction between an alkyl ester of a dicarboxylic acid and a glycol, the phosphorus compound can be added as a zinc salt, Since it reduces the effectiveness of transesterification catalysts such as cobalt salts and manganese salts, it is added after the transesterification reaction is completed. Furthermore, although TBA-EO can usually be easily produced by tetrabrominating bisphenol A and then adding ethylene oxide, the TBA-EO used in the present invention
EO must satisfy the conditions for the A and B values described above.

(The A and B values were measured according to the method described in JIS-K-1527-1961). To lower the A and B values of TBA-EO (7), distill at a high vacuum of about 0.02 Torr/240°C or less, use an adsorbent such as activated carbon, or use a gas such as air or nitrogen. It is best to recrystallize using methanol, acetone, etc. as a solvent while bubbling (in the normal recrystallization method, colored impurities or coloring substances are re-adsorbed during recrystallization.

). TBA-EO is added to the reaction system during the esterification or transesterification reaction of dicarboxylic acid or its ester-forming derivative with glycol or after the completion of these reactions. Unless the above conditions are satisfied, it is difficult to produce a copolyester with a high degree of polymerization and high whiteness.

The amount of arylphosphonic acid or its ester-forming derivative and TBA-EO to be added is such that the phosphorus content in the produced copolyester is 0.05 to 0.5% by weight and the bromine content is 5% by weight.
The amount should be ~15% by weight.

If the amount is less than this range, no flame retardant effect can be expected due to the synergistic effect of phosphorus and bromine, and if it exceeds this range, not only will the flame retardant effect not improve any further, but the resulting copolyester may be colored or its physical properties may deteriorate. I do things. The copolycondensation reaction is usually carried out according to a known method, for example, in the presence of a polycondensation catalyst such as an antimony compound or a germanium compound.
This can be achieved by reacting under high vacuum at a temperature of 220-280°C.

Polymerization at a temperature slightly lower than the melting point of the resulting copolyester, ie, solid phase polymerization, is also applicable. The copolyester obtained by the present invention exhibits good properties as fibers, films, and plastics, and has high flame retardant performance, so its utility value is extremely high.

In addition, after blending the copolyester obtained in the present invention, the phosphorus content is 0.05 to 0.5% by weight, and the bromine content is 5 to 15% by weight.
It is also possible to use it in combination or in combination with other polyesters such as polyethylene terephthalate within a range of weight %.

The present invention will be specifically explained below using Examples.

Example 1 194 parts (1 mole part) of dimethyl terephthalate
, 112 parts (1.8 mol parts) of ethylene glycol, and 0.022 parts (1X10-4 mol parts) of zinc acetate dihydrate were placed in an autoclave equipped with a stirrer, and the mixture was heated at 150 mol in a nitrogen atmosphere.
A transesterification reaction was carried out while distilling methanol and ethylene glycol at ~200°C for 7 hours to obtain 220 parts of bis(β-hydroxyethyl) terephthalate oligomer with a transesterification reaction rate of 99.5%.

Then, A and B purified by 1.58 parts (0.01 mole part) of phenylphosphonic acid and vacuum distillation (0.02 torr/24'C) were 10 and 40 parts, respectively (therefore, A/B=0.
Add 63.2 parts (0.1 mol parts) of TBA・EO from 25) and 0.058 parts (2 x 10-4 mol parts) of antimony trioxide to bring the internal temperature to 265°C, gradually reduce the pressure, and boil for 1 hour. The polycondensation reaction was carried out for 4 hours. The obtained copolyester has extremely high whiteness, the intrinsic viscosity at 25°C in a 1:1 mixed solvent of phenol and tetrachloroethane is 0.70, the carboxyl group in the copolyester is 10 equivalents/ton, and the phosphorus content is 0. .10% by weight, and the bromine content is 11.8% by weight (thus (x+10)/1
00:10.215). After chipping this copolyester and drying it under reduced pressure at 150°C for 5 hours, using an extruder type 1 melt spinning machine, the melting temperature was 265°C,
Melt spinning was performed at a spinning speed of 6001 n/min and a nozzle hole number of 24, and then at a stretching temperature of 150°C and a stretching speed of 50.
Stretched at 0m/Mlnl stretch ratio of 3.5 times, 10
A copolyester fiber of 0 denier/24 filaments was obtained. The operability during spinning is good, and the fiber strength is 4.
59/d1 elongation was 10%. After tubular knitting, this fiber was refined according to a conventional method, and its flame retardancy was examined using the coil method of JIS-L-1091-1971 and the oxygen index method of JIS-K-7201-1972. The number of times is 6
The limiting oxygen index was 34, and it was recognized that the material had excellent flame retardant performance. Examples 2 to 4 The same operations as in Example 1 were performed except that the quality of TBA-EO, the amount added, and the phosphorus compound were changed.

The results are shown in Table 1.

As can be seen from the table, both systems have a high degree of polymerization,
Copolyesters with low terminal carboxyl groups have been obtained.

Moreover, the color tone was excellent, and the properties and flame retardant performance of the fiber obtained by spinning as in Example 1 were also excellent. Comparative Example 1 A and B obtained by recrystallizing 220 parts of bis(β-hydroxyethyl) terephthalate obtained in the same manner as in Example 1 and commercially available TBA-EO with isopropanol were 20 parts each,
90 (therefore B>80), 63.2 parts (0.1 mole part) of TBA-EO, 1.58 parts (0.1 mole part) of phenylphosphonic acid.
．． 01 mole part) and antimony trioxide 0.058 part (
2 x 10-4 mol parts) was charged into an autoclave equipped with a stirrer, and heated at 230°C for 1 hour under a nitrogen atmosphere, then for 24 hours.
The temperature was raised to 0°C, and the pressure was gradually reduced to reach 0.1 Torr in 1 hour, and the polycondensation reaction was carried out for 2 hours.

The temperature was further raised to 265°C, and polycondensation was carried out for 4 hours. The obtained copolyester has a yellowish brown color and an intrinsic viscosity of 0.
．． The 501 terminal carboxyl group was 54.3 equivalents/ton, the phosphorus content was 0.12% by weight, and the bromine content was 11.5% by weight. This copolyester was threaded in exactly the same manner as in Example 1, but thread breakage occurred frequently.

Comparative Examples 2 and 3 Except for changing the quality of TBA-EO in Example 1,
The same operation as in Example 1 was carried out and the results are shown in Table 2.

As can be seen from the table, no satisfactory results were obtained in either case.

Claims (1)

[Scope of Claims] 1. Dicarboxylic acid or its ester-forming derivative, glycol, arylphosphonic acid or its ester-forming derivative, and 2,2-bis(3'-5'-dibrom-4
'-β-oxyethoxyphenyl)propane (TBA・
The phosphorus content in the copolyester produced from EO) is 0.0.
5 to 0.5 wt%, bromine content x (wt%) is 5 to 15
When producing a copolyester, B≦80, A
A method for producing a flame-retardant copolyester, characterized by using TBA/EO that satisfies /B≧(x+10)/100. Here, A and B are TBA・EO 10g/methanol 1d
B shows the APHA value of a solution with a concentration of 1, B shows the value for TBA·EO heat-treated at 250° C. for 3 hours in a nitrogen atmosphere, and A shows the value for TBA·EO before the heat treatment. 2. The method according to claim 1, wherein the dicarboxylic acid is terephthalic acid and the glycol is ethylene glycol. 3. The method according to claim 1, wherein the arylphosphonic acid is phenylphosphonic acid. 4. The method according to claim 1, wherein the TBA·EO is distilled under a high vacuum of 0.02 torr/240° C. or less.