JPH05140283A - Flame-retardant copolyester - Google Patents

Abstract

PURPOSE:To prepare a copolyester having improved whiteness, light resistance, and washing resistance by copolymerizing a dicarboxylic acid component, a glycol component, and a specific phosphorus compd. CONSTITUTION:The objective copolyester is prepd. by copolymerizing a dicarboxylic acid component mainly comprising terephthalic acid, a glycol component mainly comprising ethylene glycol, and a phosphorus compd. of the formula (wherein A is a di- or trivalent org. residue; R is a monovalent ester-forming group; (n) is 1-2; and two broken lines indicate a mixture of two isomers in one of which a phosphorus atom is bonded to a carbon atom at a site different from the other's) in an amt. of phosphorus atom of 2,000-30,000ppm based on the copolyester.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a flame-retardant synthetic linear polyester copolymer modified with a phosphorus-containing compound. More specifically, in producing a polyester having polyethylene terephthalate or polybutylene terephthalate as a main component, a phosphorus-containing compound of a 9-phosphabicyclononane derivative is added and copolymerized, which is a flame-retardant polyester copolymer. It is about.

[0002]

2. Description of the Related Art Aromatic polyesters represented by polyethylene terephthalate, which have excellent mechanical properties, are widely used as fibers, films and other plastic moldings and are extremely useful materials. At the same time, however, it has a drawback that it is easy to burn, and with the recent increase in awareness of fire, there is a strong demand for flame retardancy. In particular, the generation of toxic gases (cyan, halogen) at the time of combustion is regarded as a problem, and therefore development of flame-retardant products that do not generate toxic gas is under much demand.

Various attempts have been hitherto made to make polyester flame-retardant. For example, a method of post-treating a flame-retardant agent on a molded article such as fiber or film, and a method of kneading the flame-retardant agent at the time of molding are known. However, the post-treatment method has various drawbacks such as complicated treatment, non-uniformity, rough texture of the molded product, and reduced flame retardancy due to washing and the like. Further, in the kneading method, the flame retardant is sublimated or colored during molding, or the mechanical properties of the molded product are remarkably deteriorated. Furthermore, when a molded product such as a textile product is dry-cleaned, the flame retardant may come off or bleed out, resulting in a number of drawbacks such as deterioration in performance and hygiene due to contamination.

A so-called copolymerization method in which a phosphorus atom, which is one of the atoms imparting flame retardancy, is introduced into the main chain of the polyester molecule is effective as a method for improving such drawbacks, and various studies have been made in recent years. There are many suggestions. For example, JP-B-36-21050 and JP-B-38-9447 disclose methods of adding phosphonic acid or phosphonic acid esters. However, these proposed phosphonates generally have a low boiling point or cause a side reaction during the production of the basic aromatic polyester to be distilled out of the system, or the molding processability due to three-dimensionalization is difficult. It has the drawback of being impossible. Further, JP-B-36-20771 discloses a method of adding and copolymerizing a bifunctional, relatively high-boiling point phenylphosphonic acid bisglycol ester. However, it has a drawback that it is often distilled out of the system during the polymerization despite the high boiling point. The cause of this distillation out of the system is not clear, but self-condensation probably takes precedence,
It is presumed that it becomes a cyclic low boiling point component and volatilizes.

In order to improve such drawbacks, for example, Japanese Patent Publication No. 47-13386 and Japanese Patent Laid-Open No. 50-39389 are added and copolymerized with a polymer of phosphonic acid, or phosphates having a trifunctional group are also added and copolymerized. A method of doing so is disclosed. Since such a method is a polymer and has a high boiling point, it is possible to considerably reduce the distillation outside the system, but when the degree of polymerization is large, the reactivity of the terminal functional group becomes poor and it is difficult to introduce it into the polyester main chain, and the mechanical properties of the polyester Deterioration,
It has drawbacks such as elution of unreacted substances and obstacles such as gelation due to trifunctional groups. On the other hand, if the degree of polymerization is low enough not to reduce the reactivity, side reactions occur as described above and scatter out of the system, or the thermal stability is insufficient, resulting in a marked decrease in the whiteness and mechanical properties of the polyester. However, it has a drawback that it cannot be put to practical use. The publication also describes an example in which a divalent aromatic group having good thermal stability is used, but since the terminal functional group is a phenolic hydroxyl group, the ester forming property is poor and the degree of polymerization is sufficient. It has the drawback that

Further, in JP-A-53-68756, phenylphosphonic acid and a polymerization catalyst are added after the transesterification reaction,
A method is disclosed in which the esterification reaction is allowed to proceed under mild conditions and then the polymerization is carried out. However, under mild conditions that suppress the formation of cyclic compounds with low boiling points, the esterification does not proceed, and under the conditions that allow the esterification to proceed sufficiently, the phosphorus compound will distill out of the system and a satisfactory product cannot be obtained. However, the current situation is that a practical product has not yet been obtained.

[0007]

DISCLOSURE OF THE INVENTION The present invention is to solve the above-mentioned drawbacks of the prior art and to find a flame-retardant copolymerization component which is effective in a small amount and is non-polluting.

A first object of the present invention is to provide a yarn, without deteriorating the original mechanical properties and thermal properties of polyester,
It is intended to provide a flame-retardant polyester copolymer which can be formed into a fiber or a film and is excellent in whiteness, light resistance and washing resistance. A second object of the present invention is to provide a useful flame-retardant polyester in which the flame-retardant copolymer component does not volatilize or decompose or scatter out of the system during polymerization or molding of the polyester and does not inhibit polymerization and has excellent heat resistance. To provide a copolymer. A third object of the present invention is to provide a flame-retardant polyester copolymer which does not generate a harmful gas to the human body upon contact with flame and has an extremely excellent self-extinguishing property, and which can be easily and inexpensively produced industrially. is there.

[0009]

Means for Solving the Problems As a result of various investigations and various studies on the flame retardant copolymerization component, the present inventors have found that if a phosphine oxide derivative having a specific structure described later is used, a normal polyester can be obtained. It was found that a linear polyester copolymer can be obtained with almost no problems in the same manner as in the case of polymerization, and that the polyester has an extremely low content of ether bonds and has excellent flame retardancy. Came to do.

That is, the present invention provides a polyester copolymer comprising a dicarboxylic acid containing terephthalic acid as a main component or an ester-forming derivative thereof and a glycol containing ethylene glycol as a main component or an ester-forming derivative thereof with a general formula: (I)

[Chemical 2] (In the formula, A is a divalent or trivalent organic residue (not containing halogen), R is a monovalent ester-forming functional group,
n represents an integer of 1 to 2, and the two broken lines represent a mixture of isomers in which the position of the C atom bonded to the P atom is different. )
The phosphorus atom content in the polyester is 2,000 to 30,0 at least one of the phosphorus-containing compounds represented by
It is a polyester copolymer characterized by being copolymerized so as to be 00 ppm.

The second aspect of the present invention is a fiber, film or resin molded product comprising the above polyester copolymer.

Aromatic dicarboxylic acid components used in the copolymer of the present invention include terephthalic acid, isophthalic acid,
2.6-naphthalenedicarboxylic acid, 1.5-naphthalenedicarboxylic acid, 4.4-diphenyldicarboxylic acid, bis- (4-carboxyphenyl) ether, bis- (4-
Carboxyphenyl) sulfone, 1.2-bis (4-carboxyphenoxy) ethane, 5-sodium sulfoisophthalic acid, 5-sulfopropoxyisophthalic acid, diphenyl p. p'-dicarboxylic acid, p-phenylenediacetic acid, diphenyl oxide-p. p'-dicarboxylic acid, t
Examples include rans-hexahydroterephthalic acid and ester-forming derivatives thereof such as alkyl ester, aryl ester, and ethylene glycol ester. Among them, terephthalic acid, 2.6- is particularly useful.
The main component is naphthalenedicarboxylic acid, and 10 mol% of one or more of these aromatic dicarboxylic acids and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, decamethylenedicarboxylic acid and their ester-forming derivatives are used. The limit is to mix and use a small amount.

On the other hand, as the glycol component, ethylene glycol, 1.2-propylene glycol, 1.4-butanediol, trimethylene glycol, 1.6-hexanediol, 1.4-cyclohexanediol, neopentyl glycol, 1. 4-cyclohexanedimethanol, bisphenol A, bisphenol S, diethylene glycol, polyethylene glycol, polypropylene glycol and the like can be mentioned. Among them, what is useful is to use ethylene glycol, 1.4-butanediol as a main component, and to mix and use one or more of these glycol components in a small amount up to 10 mol% of the diol component. ..

As the oxycarboxylic acid component, 4
-Oxybenzoic acid, 4-hydroxyethoxybenzoic acid,
Examples thereof include oxypivalic acid, and these can be added in a small amount if necessary.

If the polyester copolymer of the present invention is a substantially linear polymer, optionally a small amount of a monofunctional compound such as benzoic acid, benzoylbenzoic acid, acetic acid, methoxypolyethylene glycol, or the like, or It is also possible to add trifunctional or higher functional compounds such as glycerin, pentaerythritol, trimellitic acid, pyromellitic acid, phosphoric acid compounds and ester-forming derivatives thereof.

As described above, the copolymer of the present invention comprises an aromatic dicarboxylic acid component containing terephthalic acid or 2.6-naphthalenedicarboxylic acid as a main component and ethylene glycol or a glycol containing 1.4-butanediol as a main component. In producing an aromatic polyester having 4-oxybenzoic acid as a main component, the phosphorus-containing bishydroxy compound represented by the general formula (I) is added and copolymerized. As a method for producing such a copolymer, a conventionally known method can be applied. In that case, the timing of addition can be selected and added as necessary, such as in the transesterification reaction step, before polycondensation, during polycondensation, or just before the completion of polycondensation. However, although the product of the present invention is not restricted by such a timing of addition, since the phosphorus-containing bishydroxy compound already has a glycol ester structure, it is preferably added in a step after completion of the transesterification reaction. As a matter of course, a known catalyst can be used for the transesterification reaction and the polycondensation reaction.

Pigments, matting agents, optical brighteners, heat stabilizers, UV absorbers, antioxidants, antistatic agents, organic amines, organic carboxylic acid amides, etc. during the production or molding of the copolyester. Even if various kinds of ether bond inhibitors, etc. are used according to the purpose, they do not depart from the spirit of the present invention.

The phosphorus-containing compound represented by the general formula (I) has a phosphorus atom content of 2,0 in the obtained polyester.
00-30,000 ppm, preferably 3,000-2
10,000 ppm, more preferably 5,000-15,
Copolymerization is carried out by adding it so as to be 000 ppm. Of course, depending on the composition of the dicarboxylic acid and glycol component used, if the ester-forming functional group of the phosphorus-containing compound is a hydroxyl group, it is generally within the range of 2 to 20 mol% of the total glycol component. When the ester-forming functional group of the phosphorus-containing compound is a carboxylic acid group derivative, the range of 2 to 20 mol% of the total acid component is also suitable. When the content of phosphorus in the polyester is less than 2,000 ppm, there is no flame retardant effect, while when it is more than 30,000 ppm, the flame retardant effect is saturated and various characteristics inherent to the polyester are significantly lowered, which is preferable. Absent. Of course, it is also possible to prepare a high content polyester copolymer once, mix it with a normal polyester so as to have a desired phosphorus content, and mold it, or form a fiber.

In the present invention, the phosphorus-containing compound used for producing the flame-retardant polyester copolymer is represented by the above general formula (I), in which R is a monovalent ester. Having a functional group, specifically, a carboxyl group, an alkyl ester having 1 to 6 carbon atoms in the carboxyl group, a cycloalkyl ester, an aryl ester,
Preferred examples include a hydroxylalkoxycarbonyl group having 2 to 7 carbon atoms, an anhydrous carboxyl group, and a hydroxyl group. Among them, a carboxylic acid and its derivative which have a high boiling point of the obtained phosphorus-containing compound and do not distill out of the system in the polycondensation step are preferable.

If n in the formula is one, it may be introduced at the polymer terminal and act as a reaction terminator, which may cause an adverse effect such as a decrease in viscosity. Therefore, known polyfunctional compounds such as those mentioned above may be used. Pentaerythritol, trifunctional carboxylic acid and the like are preferably used in combination. When the number n of monovalent ester-forming functional groups is 2, the polymerization can be carried out in the same manner as a usual polyester without being introduced into the polymer main chain to cause polymerization inhibition or gelation. Therefore, even if the number n of monovalent ester-forming functional groups is 1, the object can be sufficiently achieved, but since more phosphorus atoms can be introduced and no complicated operation is required and the original characteristics of the polyester are not impaired. , And the number of n is 2 is more preferable.

On the other hand, as A of the general formula (I), a lower alkylene group such as methylene, ethylene, 1.2-propylene and 1.3-propylene, a 1.3-phenylene group,
1.4 phenylene, 1,4-xylylene, -CH ₂
A divalent group which is an arylene group such as —C ₆ H ₄ — and an alkylarylene group, and

[Chemical 3]

[Chemical 4] And a trivalent group represented by

The following are specific examples of the phosphorus-containing compound represented by the general formula (I).

[Chemical 5]

[Chemical 6]

[Chemical 7]

[Chemical 8]

[Chemical 9]

[Chemical 10]

[Chemical 11]

[Chemical 12]

[Chemical 13]

[Chemical 14]

[Chemical 15]

[Chemical 16]

[Chemical 17]

[Chemical 18]

[Chemical 19]

[Chemical 20]

[Chemical 21]

[Chemical formula 22]

[Chemical formula 23]

[Chemical formula 24]

[Chemical 25]

[Chemical formula 26]

The above compound can be synthesized as follows. For example, the phosphorus-containing compound represented by (j) can be prepared by the method described in JP-A-62-22792, that is, 9-phosphabicyclo [3.3.1] nonane and 9-phosphabicyclo [4.2.1]. ] It is obtained by addition reaction of dimethyl maleate to a mixture of nonane and subsequent oxidation (Dokl. Akad. Nauk SSSR 85,3.
49 (1952)). Similarly, for other phosphorus-containing compounds, 9-phosphabicyclononane isomer mixture or 9-phosphabicyclononane isomer mixture
It can be synthesized by subjecting the oxo-9-phosphabicyclononane isomer mixture to an addition reaction of an unsaturated compound such as a vinyl group or a vinylidene group corresponding to the derivative. Alternatively, it can be obtained by heating a 9-oxo-9-phosphabicyclononane isomer mixture or a 9-phosphabicyclononane isomer mixture and an aromatic dihydroxy compound.

The copolymer of the present invention is copolymerized with the phosphorus-containing compound represented by the above general formula [I]. The phosphorus-containing compound is stable because the phosphorus atom is bridge-bonded to the cyclononane ring. The heat resistance is extremely excellent as compared with the case of using a known phosphorus compound. Therefore, during the polycondensation reaction, side reactions such as gelling reaction based on the thermal decomposition of phosphorus compounds hardly occur, so that the polyester copolymer of the present invention has a good color tone and has physical properties superior to conventional flame-retardant polyesters. Have Therefore, flame-retardant molded products such as fibers, films or molded products having excellent properties can be obtained from this polyester copolymer.

[0025]

As described above, the flame-retardant polyester copolymer of the present invention has a phosphorus atom imparting flame-retardant property introduced into the main chain of polyester. Is useful because it has a durability that does not elute or fall off during use of the molded product or during treatment such as washing and does not deteriorate flame retardant performance. Further, it has excellent light resistance and whiteness without impairing the original mechanical and thermal characteristics of polyester and the texture of textiles, and has good dyeability. Further, since the atom imparting flame retardancy is only the phosphorus atom, even if the molded product comes into contact with the flame, no harmful gas is generated in the human body, which is extremely safe and useful.

The flame-retardant polyester copolymer of the present invention is
Fibers and yarns can be spun, drawn, or spun by known methods and can be post-treated by ordinary methods, and ordinary weaving machines and knitting machines can be used for weaving and knitting without special consideration. .. In addition, it is mixed and spun with ordinary polyester or cationic dyeable polyester, or is woven with the above-mentioned ordinary fibers or other fibers such as cotton, polyester, and acrylic, or is a high-grade fabric such as a multi-layered fabric. It is possible to obtain high quality flame retardant polyester products. Further, shaped products such as films, foils, and bottles are industrially useful because flame-retardant products can be easily obtained by a known method by extrusion, compression or injection molding. Examples of such fiber products and molded products include thick fabrics, clothing, carpets, curtains, bags, bottles, films, structural parts, mechanically conductive parts and the like.

[0027]

EXAMPLES The effects of the method of the present invention will be described more specifically with reference to the above examples. All "parts" in the examples mean "parts by weight". The intrinsic viscosity “η” was obtained by a conventional method at 20 ° C. in a mixed solvent of phenol / tetrachloroethane = 6/4. The melting point was determined from the endothermic peak of DSC. The flame retardancy is evaluated by the number of flame contact (JIS L-1091 D) by the 45 ° coil method or the limiting oxygen index (JI).
It was measured and shown according to the SK-7201) method. After 40 hours of light resistance with a carbon arc method fedometer, the original yarn was grayscale, and the dyed ones were 5th grade with no discoloration and 1st grade with significantly discolored compared to the bluescale. It is shown in five stages. Similarly to the lightfastness sample, the whiteness was determined by closely winding a thread on a black paper and measuring the color with a colorimeter and showing the color b value.

Production Example 1 A 4-necked flask equipped with a stirrer, a condenser, a thermometer, a dropping funnel and a nitrogen gas introducing tube was charged with 9-phosphabicyclo [3.
3.1] Nonane and 9-phosphabicyclo [4.2.
1] 14.2 parts of the nonane mixture and 26 parts of toluene were added and dissolved by stirring. Then dimethyl maleate 1
5.2 parts was dropped from the dropping funnel in 40 minutes. During this time, the internal temperature rose to 61 ° C. due to heat generation. Add this to 80 ℃
It was heated to and reacted for 4.5 hours. Then, while cooling with water and maintaining the temperature below 70 ° C., stirring was intensified and 10 parts of 35% hydrogen peroxide was slowly added dropwise over 0.8 hours. After reacting for another 20 minutes, 1 drop of this reaction solution was dropped on carbon disulfide and it was confirmed that there was no red coloration due to trivalent phosphine, and then stirring was stopped. Then, it was transferred to a separating funnel and separated into toluene and an aqueous layer. Further, the toluene layer was extracted with water, combined with the water layer, and the water was distilled off with an evaporator. Methanol was added to this and once dissolved, the methanol was distilled off to obtain white crystals.

The reaction yield of the obtained product was 93.2% based on the starting material, the melting point was 73 ° C., the result of MAS analysis was 302, the molecular weight was 302, and the result of elemental analysis was C = 55.78.
%, H = 7.56%, P = 10.21%, C = 55.62% of theoretical value, H = 7.67%, P = 10.25
% Was in good agreement with the following compound.

[Chemical 27]

Production Example 2 In the same manner as in Production Example 1, 9-phosphabicyclo [3.3.1] nonane and 9-phosphabicyclo [4.
2.1] Nonane mixture 14.2 parts, toluene 18
Parts and stir to dissolve. On the other hand, 15.8 parts of dimethyl itaconate were heated and dissolved in 8 parts of toluene at 50 ° C., and the mixture was added dropwise and reacted in the same manner as in Production Example 1 to obtain white crystals in a reaction yield of 96.8%.

As a result of various analyzes of this crystal, melting point: 81 to 82 ° C., molecular weight from MAS analysis: 316, measured value of elemental analysis: C = 57.12%, H = 8.05%,
P = 9.77%, C = 56.95% of theoretical value, H
= 8.00%, P = 9.79%, which was in good agreement with the following compound.

[Chemical 28]

Production Example 3 The 4-necked flask of Production Example 1 was charged with 9-phosphabicyclo [3.
3.1] Nonane and 9-phosphabicyclo [4.2.
1] 28.5 parts of a mixture of nonane, acetonitrile 25
And 15 parts of methyl acrylate were charged, while stirring on a water bath maintained at 25 to 30 ° C., a 10 N KOH aqueous solution was added from a dropping funnel so that the temperature in the reaction system would not exceed 60 ° C.
Carefully drop the part over 40 minutes, and add 65-70
The reaction was carried out at 0 ° C for 2 hours. Then, 30% hydrogen peroxide was slowly added dropwise over 20 minutes while maintaining the same temperature, and the temperature was further raised and boiled to react for 30 minutes. It was confirmed that trivalent phosphine was not present in the same manner as in Production Example 1, and a part thereof was subjected to gas chromatography analysis to find that the reaction rate of methyl acrylate was 98.8%.
The reaction rate of 9-phosphabicyclononane was 99.4%. Then, acetonitrile and water were distilled off under reduced pressure to obtain a viscous liquid. This is distilled and 208 ℃ / 0.3mm
45.2 parts of Hg main fraction was obtained.

From the results of analysis of infrared absorption spectrum and nuclear magnetic resonance spectrum, it was found that this main distillate had the following structural formula. Also, elemental analysis results, C = 5
9.09%, H = 8.75%, P = 12.72%, C = 59.00% of theory, H = 8.67%, P =
It was in good agreement with 12.68%.

[Chemical 29]

Example 1 100 parts of dimethyl terephthalate, 72 parts of ethylene glycol, 8.2 the phosphorus-containing compound (i) obtained in Preparation Example 1
Parts and 0.04 parts of zinc acetate were heated from 150 ° C. to 220 ° C., the transesterification reaction was carried out for 3 hours while continuously distilling off the produced methanol out of the system, and then the antimony trioxide (0.1%) was added thereto. 03 parts was added, the internal pressure was reduced while gradually raising the temperature, and finally polycondensation was carried out at 280 ° C. and 0.3 mmHg for 3 hours, and then this polymer was extruded into a cord shape and cut to 2.5 mm ° × 3 mm. Pellets of the same size. No phosphorus compound, which is a flame retardant, was detected in the top lid of the polymerization kettle or in the distilled ethylene glycol, and no distillation outside the system was observed. The polymer obtained has a melting point of 2
The temperature was 54 ° C., the intrinsic viscosity was 0.63, and the residual phosphorus ratio (based on the theoretical value from the charged amount) was 97.4%.

The pellets were dried to a water content of 0.005% and then spun at a spinning temperature of 288 ° C. with a spinning speed of 80.
Melt spinning was carried out at 0 m / min, followed by drawing with a roller heater of 85 ° C. at a draw ratio of 3.94 times and a drawing speed of 1000 m / min.
It was set by a plate heater at 50 ° C. to obtain a drawn yarn of 75d / 24f.

This filament bundle was cut to a length of 22 cm, 1 g was sampled, one end was fixed, the other end was sandwiched by a hand drill, twisted 20 times, and folded in two to spontaneously untwist it for a long time. A 10 cm twist bar. J using this twisted rod
The number of times of flame contact was measured according to the IS method and was 5.8 times.

Example 2 Polymer was subjected to polycondensation in the same manner as in Example 1 except that 8.5 parts of the phosphorus-containing compound (1) of Production Example 2 was used in place of the phosphorus-containing compound used in Example 1. Got The obtained polymer had a melting point of 253 ° C., an intrinsic viscosity of 0.61, a phosphorus residual ratio of 97.7%, and a flame contact number of 5.7.

Example 3 Instead of the phosphorus-containing compound used in Example 1, 6.7 parts and 1.2 parts of the phosphorus-containing compound (b) synthesized in Production Example 3 and 0.3 part of triphenyl phosphate were added. Polycondensation was performed in the same manner as in Example 1 except that the polymer was used to obtain a polymer. The obtained polymer has a melting point of 248 ° C., an intrinsic viscosity of 0.57, and a phosphorus residual ratio of 9
It was 1.2% and the number of flame contact was 4.8 times.

Comparative Example 1 A polymer was obtained by polymerizing in the same manner as in Example 1 except that 6.0 parts of diethyl phenylphosphonate was used instead of the phosphorus-containing compound used in Example 1. The obtained polymer has an intrinsic viscosity of 0.57, a melting point of 256 ° C., and a phosphorus residual ratio of 43.
%, A considerable amount of phosphorus was distilled out. The number of times of flame contact was 3.7 times.

Example 4 100 parts of dimethyl terephthalate, 70 parts of ethylene glycol and 0.04 part of zinc acetate were heated from 150 ° C. to 220 ° C., and the produced methanol was continuously distilled out of the system for 3 hours for transesterification. After the reaction, 0.03 parts of antimony trioxide and the phosphorus-containing compound (n) were further added.

[Chemical 30] Was added in various amounts, the internal pressure was reduced while gradually raising the temperature, and finally polycondensation was carried out at 280 ° C. and 0.3 mmHg for 3 hours, and then this polymer was extruded into a cord and cut into pellets. Created.

The physical properties of the obtained polymer and the results of measuring the light resistance, whiteness and the number of times of contact with flame by spinning and stretching in the same manner as in Example 1 are summarized in Table 1.

[0042]

[Table 1]

As is clear from Table 1, the phosphorus content is 2,
The flame-retardant property of 000 ppm or less (No. 1) is insufficient, and the flame-retardant property is saturated if more than necessary, and on the contrary, the physical properties of polyester are deteriorated. It can be seen that those within the scope of the invention have excellent performance.

Comparative Example 2 In Example 4, instead of the phosphorus-containing compound, bis- (2-
Hydroxyethyl) phenylphosphonic acid oxide 10
Polycondensation was carried out in the same manner as in Example 1 except that a part was added. The phosphorus compound was distilled out during the polycondensation, and the phosphorus content in the obtained polyester was measured. As a result, the residual rate of phosphorus was 29.
%Met. This polyester copolymer was spun and stretched according to Example 1, and the performance was measured. As a result, the number of flame contact was 2.
It was inferior to once.

Example 5 Two copolyester stretched yarns modified in No. 3 of Examples 1, 2 and 4 were combined to obtain a tubular knitted product with a tubular knitting machine. These tube-knitted samples were made into Miketon Polyester
Table 2 shows the results of evaluation of the number of times of flame contact after 20 times of high-pressure dyeing with Blue FBL 2% owf and washing with a household washing machine and dry cleaning were repeated.

[0046]

[Table 2]

As is clear from Table 2, the flame-retardant copolyester of the present invention has very good heat resistance and wash resistance.

Claims (3)

[Claims] 1. A polyester copolymer comprising a dicarboxylic acid containing terephthalic acid as a main component or an ester-forming derivative thereof and a glycol containing ethylene glycol as a main component and having the general formula (I): (In the formula, A is a divalent or trivalent organic residue, R is a monovalent ester-forming functional group, n is an integer of 1 to 2, and two broken lines are bonded to a P atom. At least one of the phosphorus-containing compounds represented by a mixture of isomers having different C atom positions is copolymerized so that the phosphorus atom content in the polyester is 2,000 to 30,000 ppm. A polyester copolymer characterized by the above. 2. The polyester copolymer according to claim 1, wherein R in the general formula (I) is a carboxylic acid group or an ester-forming derivative thereof. 3. A fiber, film or resin molded product comprising the polyester copolymer according to claim 1.