KR100236755B1 - Process for preparing flame-retardant polyester - Google Patents

Abstract

The present invention is to produce a polyester having a low physical property degradation of the polymer, excellent spinning workability, excellent flame retardancy in the weaving state, and excellent thermal stability and flame retardancy of a desired degree of polymerization at a normal PET polymerization time level. In preparing a polyester from at least one dicarboxylic acid or its ester forming derivative and at least one diol or its ester forming derivative via esterification and polycondensation, the phosphorus atom content in the polyester is 400 The following compound of formula (I) is added at the beginning of the esterification reaction so as to obtain 40,000 ppm, and the metal oxide (II) is added at an amount of 100 to 1,000 ppm of the resulting poly group at the beginning of the polycondensation reaction. .

(In Formula (I), R ₁ , R ₂ are alkyl or aryl groups, R ₃ is H or alkyl groups, n is an integer of 1 2)

Description

[Name of invention]

Manufacturing method of flame retardant polyester

Detailed description of the invention

The present invention relates to a method for producing a flame retardant polyester, and more particularly, to a poly-polyester having excellent flame retardancy while reducing the intrinsic physical properties of a polymer by copolymerizing a new reactive flame retardant to a polyester comprising a combination of diol and dicarboxylic acid or ester. It relates to a method for producing an ester.

In general, polyester, particularly polyethylene terephthalate (hereinafter PET) has excellent mechanical properties, good chemical resistance such as chemical resistance, and excellent electrical properties such as electrical insulation, and is widely used in fibers, films, and engineering plastics. However, these conventional polyesters have a disadvantage in that they are easily burned, and thus flame retardancy is urgently required in terms of fire prevention in various moldings including fibers.

As a method of imparting flame retardancy to conventional polyester fibers, a method of mixing and spinning by adding a non-reactive flame retardant in a spinning transfer step after polymerization (Japanese Patent Publication No. 45-2303, 47-5413, US Patent No. 3,719,727) Surface treatment method of coating or impregnating the surface of the fiber in the post-spinning process (Japanese Patent Laid-Open Nos. 62-299574, 63-190080, 63-309674) and copolymerizing a reactive flame retardant such as an organic halogen or an organic phosphorus compound ( Japanese Patent Laid-Open Nos. 51-66339, 52-47891, US Patent Nos. 3,941,752, 4,033,936) and the like. Among these methods, in view of excellent durability, flame retardancy, and low physical property deterioration, a method of incorporating a flame retardant in copolymerization is most advantageous.

On the other hand, when halogen-containing flame retardants are used in the method of imparting flame retardancy by copolymerization, halogen compounds are easily thermally decomposed at high temperature, and thus, a large amount of flame retardants must be added to obtain effective flame retardancy. Will be produced.

In addition, when the organophosphorus compound is used as a flame retardant, the organophosphorus compound itself does not have good thermal stability, there is a problem that the physical properties of the polymer tend to be lowered due to its low reactivity with polyester, and it does not exhibit sufficient flame retardant effect. The two types of reactive phosphorus flame retardants used in Japanese Patent Application Laid-Open No. 52-47891 and US Patent No. 3,941,752 have a problem of large cost increase due to the use of expensive raw materials and are not easily obtained commercially.

The present inventors have diligently studied to solve the problems of the conventional methods, and found that the above problems can be solved when using a novel reactive phosphorus compound (I) which can be easily synthesized at high efficiency in polyester production. .

(In Formula (I), R ₁ , R ₂ are alkyl or aryl groups, R ₃ is H or alkyl groups, n is an integer of 1 2)

On the other hand, in Korean Patent Publication No. 95-2610, in order to minimize the thermal decomposition of the polymer and the flame retardant during the polycondensation process, liquid phase polymerization is carried out up to a certain degree of polymerization, and then solid state polymerization is carried out to a desired degree of polymerization at a temperature below the decomposition start temperature of the flame retardant. By improving thermal stability, radioactivity and flame retardancy, it is possible to prevent the trimming phenomenon caused by flame retardant decomposition products in the copolymer which does not occur in the solid phase polymerization and at the same time, it is easy to control the viscosity without accompanying thermal decomposition of the copolymer. Doing. However, the above method has a disadvantage in that a double process to liquid-phase polymerization and a price increase is followed.

The present inventors have also studied diligently to solve the problems of the prior arts related to the above problem and found that the problem can be solved when the metal oxide is introduced in the amount of 100-1,000 ppm of the polymer produced during the polymerization reaction.

That is, the present invention is prepared by adding a new reactive phosphorus-based compound (I) to prepare a flame-retardant polyester which is less deteriorated in the physical properties of the polymer, has excellent spinning workability, and is excellent in flame retardancy in the weaving state. It is an object of the present invention to prepare a polyester having excellent thermal stability and flame retardancy of a desired degree of polymerization at a PET polymerization time level.

Hereinafter, the present invention will be described in detail.

In the present invention, when producing a flame retardant polyester from at least one or more dicarboxylic acids or ester-forming derivatives thereof and at least one or more diols or ester-forming derivatives thereof, the phosphorus atom content in the polyester is 400-. The compound of the following general formula (I) is added to 40,000 ppm, and in order to obtain a polymer having a desired degree of polymerization at a normal PET polymerization time level, methacrylic oxide (II) is added in an amount of 100 to 1,000 ppm of the resulting polymer during the polymerization reaction. do.

(In Formula (I), R ₁ , R ₂ are alkyl or aryl groups, R ₃ is H or alkyl groups, n is an integer of 1 2)

Dicarboxylic acid components used to prepare the flame retardant polyesters of the present invention include terephthalic acid, isophthalic acid, diphenyl dicarboxylic acid, 1,4-dicarboxylic acid naphthalene or ester-forming derivatives thereof, adipic acid, cyclodica Lenic acid etc. can be mentioned.

As the diol component used in the present invention, one of compounds such as ethylene glycol, 1, 2-propanediol, 2, 3-butanediol, cyclohexane-1, 4-diol, and polyethylene glycol can be selected and used.

As the phosphorus compound of the general formula (I), a dialkyl (or aryl) phosphonoyl-1-2-diol derivative is used, and the compounds of the general formulas (I) and (II) are introduced into the polymerization process to make the present invention. When producing the flame-retardant polyester composition of, it is appropriate to adjust so that the phosphorus content in the polymer obtained is 400-40,000 ppm.

If the phosphorus atom content is less than 400ppm, the desired flame retardant effect is not expected, and if it exceeds 40,000ppm, it is not preferable because not only the physical properties of the produced polyester are degraded but also the productivity during spinning is lowered.

In addition, the metal oxide used to control the polycondensation reaction time of the flame retardant polyester of the present invention to the normal PET polycondensation time level is preferably added to 100-1,000ppm, if less than 100ppm within a certain polymerization time It is difficult to obtain a polymer having a desired degree of polymerization, and a problem of deterioration of physical properties and flame retardancy of the polymer occurs when the amount is added in excess of 1000 ppm.

The phosphorus-based flame retardant of the general formula (I) is preferably added at the beginning of the esterification reaction, and the metal oxide of the general formula (II) is preferably added at the beginning of the polycondensation reaction.

The polyester polymer according to the present invention prepared as described above has the advantage of low intrinsic viscosity decrease, excellent spinning workability and flame retardancy, and can be easily obtained more economically than the flame retardant used in the prior art, which has the advantage of low cost burden.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Measurement of physical properties]

(1) Intrinsic viscosity of flame retardant polyester polymer: measured at 25 ° C. using o-chlorophenol solution.

(2) Melting point: measured using a differential scanning train analyzer.

(3) Phosphorus atom content in polyester: Quantified by fluorescence X-ray method.

* Flame retardancy: evaluation of flame retardancy by producing polyester knitted by spinning after stretching polyester polymer

(4) Limit oxygen index (L.O.I.): Measured by oxygen coefficient flammability gauge according to ASTM-D-2863-70.

(5) Number of times of dyeing: evaluated by 45 ° coil method by micro burner based on JIS-L-1092D method.

[Types of Flame Retardants Used in Examples]

la: R ₁ , R ₂ = Ph, R ₃ = H, n = 1 (diarylphosphonoyl-1, 2-diol)

lb: R ₁ , R ₂ = Ph, R ₃ = methyl, n = 1

lc: R ₁ = ethyl group, R ₂ = methyl group, R ₃ = H, n = 2

ld: R ₁ , R ₂ = methyl group, R ₃ = methyl group, n = 2

Example 1

8,390 parts by weight of terephthalic acid, 3,137 parts by weight of ethylene glycol, 450 parts by weight of diarylphosphonoyl-1 and 2-diol (la) (1.63 mol) were added to an ester reactor for 3 hours while the resulting water was discharged out of the system. It reacted by heating up to 250 degreeC. After the completion of the transesterification reaction, 50 parts by weight of TMP as a stabilizer, 350 parts by weight of antimony trioxide as a polycondensation catalyst and 400 ppm of MgO were added at regular intervals, and the internal temperature of the reactor equipped with the stirrer and glycol condenser was 230 ° C to 280 ° C. The pressure of the reactor was raised to a high vacuum of 0.1 mmHg from normal pressure, and finally a polymer having an intrinsic viscosity of 0.64 was obtained.

The obtained polymer was spun and stretched according to the conventional method to produce a stretched yarn of 150/48 filaments, and weaved again to measure flame retardancy. The evaluation results are shown in Table 1.

[Examples 2-6]

A flame retardant and a metal oxide (MO) were carried out in the same manner as in Example 1 except that the amount and the amount of the charge were as shown in Table 1, and the results are shown in Table 1.

Comparative Example 1

Except not adding the metal oxide was carried out in the same manner as in Example 1 and the physical properties were evaluated and the results are shown in Table 1.

TABLE 1

Claims (1)

In preparing a polyester from at least one or more dicarboxylic acids or ester-forming derivatives thereof and at least one or more diols or ester-forming derivatives thereof through esterification and polycondensation, the phosphorus atom content in the polyester The compound of the following general formula (I) is introduced at the beginning of the esterification reaction so as to be 400-40,000 ppm, and the metal oxide (II) is introduced at an amount of 100 to 1,000 ppm of the resulting poly group at the beginning of the polycondensation reaction. Method for producing a flame retardant polyester. (In Formula (I), R ₁ , R ₂ are alkyl or aryl groups, R ₃ is H or alkyl groups, n is an integer of 1 2)