JP2883778B2 - Method for producing flame-retardant polyester fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a novel flame-retardant polyester fiber containing a phosphorus-based flame retardant.

[0002] Aromatic polyesters represented by polyethylene terephthalate have excellent mechanical properties and are extremely useful materials widely used as fibers, films and other plastic molded products. While
It has a drawback that it is easy to burn, and in recent years, with increasing awareness of fires, there is a strong demand for flame retardancy.
In addition, the generation of toxic gases (cyan and halogen) during combustion is a problem beyond flame retardancy, and development of flame-retardant products that do not generate these toxic gases is expected.

[0003]

2. Description of the Related Art Various attempts have been made to make polyester polyester flame-retardant. For example, a method of post-treating a flame retardant to a molded product such as a fiber or a film, and a method of kneading the flame retardant during molding are known. However, the post-treatment method has various drawbacks such as complicated or non-uniform treatment, roughening of the texture of the molded product, and reduction in flame retardancy due to washing or the like.

[0004] In the kneading method, the flame retardant sublimates or is colored at the time of molding, or the mechanical properties of the molded product are significantly reduced. Further, when a molded article such as a fiber product is dry-cleaned, the flame retardant is dropped off or bleeds out, resulting in a number of drawbacks such as deterioration in performance and hygiene problems due to contamination.

As a method for remedying such a defect, a so-called copolymerization method in which a phosphorus atom, which is one of the atoms imparting flame retardancy, is introduced into the molecular main chain of the polyester is effective, and various studies have been made in recent years. There are many suggestions. For example, JP-B-36-21050 and JP-B-38-9947 disclose methods of adding phosphonic acids or phosphonic acid esters. However, these phosphonic esters generally have a low boiling point, and thus have drawbacks such as being distilled out of the system during polymerization or causing a three-dimensional side reaction during the production of polyester, making molding difficult or impossible. Tokunosho 3
JP-A-6-20771 discloses a method of adding and copolymerizing bisglycol phosphonate having a relatively high boiling point. However, despite the high boiling point, there is a drawback that cyclic low-boiling substances are generated by self-condensation during polymerization, and many of them are volatilized out of the system.

JP-B-53-13479 and JP-A-50-53354 disclose copolymerization of carboxyphosphinic acid. Such phosphine compounds have no volatility and have excellent flame resistance. However, since the ester-forming functional group is a carboxyl group and a P-OH group of a phosphoric acid bond, the reaction rate is slightly different and the uniformity is somewhat lacking. Further, in terms of heat resistance, the P—O—C bond has a slight disadvantage that it is inferior to the P—C bond. In addition, Japanese Patent Publication No. 55-41610 discloses a method of copolymerizing a phosphorus-containing carboxylic acid compound derived from oxaphosphane oxide and itaconic acid. This method also has excellent flame resistance. However, since it is a complex compound having a polycyclic structure, it has a drawback that crystallinity, melting point, physical properties and the like are reduced due to steric hindrance, or molecular cleavage is easily caused by slight light or heat.

[0007] German Patent Publication No. 1232348 discloses a polyester obtained by copolymerizing bis- (p-carboxyphenyl) -phosphinic acid, which is intended for polyester modification such as improvement of dyeing and contains phosphorus. The amount is small and little flame retardancy is imparted. On the other hand, U.S. Pat. No. 4,127,566 discloses a polyester obtained by copolymerizing bis- (carboxyethyl) methylphosphine oxide. This shows good flame retardancy, but has the drawback that the melting point of the copolymer is greatly reduced and the heat resistance is slightly low.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to improve the disadvantages of the prior art and to find a flame-retardant copolymer component which is effective in small amounts and which is harmless.

An object of the present invention is to provide a flame-retardant polyester fiber which is excellent in fiber moldability and excellent in whiteness, light resistance and washing resistance without deteriorating the mechanical properties and thermal properties inherent in polyester. And an industrially inexpensive production method thereof.

[0010]

Means for Solving the Problems The present inventors have conducted various studies on the flame-retardant copolymerization component and conducted intensive studies. As a result, from the viewpoint of flame-retardant performance, the phosphorus-containing compound represented by the above-mentioned general formula was converted to a polymer. It was found that good flame retardancy was imparted without deteriorating heat resistance and mechanical properties, and flame retardant fibers were proposed first. The present inventors have further studied the production method of the fiber, and as a result, have reached the present invention.

That is, the method for producing the flame-retardant polyester fiber of the present invention is represented by the general formula

Wherein R is an allyl group having 6 to 9 carbon atoms, an aralkyl group, R ′ is H or an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, and R ″ is H or a methyl group. The compound A, which is derived from at least one of the phosphorus-containing dicarboxylic acid compounds or derivatives thereof represented by the formula (1) and has a phosphorus content of at least 3% by weight, is obtained by polymerizing the fiber-forming polyester at the time of polymerization of the fiber-forming polyester. Is polymerized at a concentration of at least 2000 ppm, and then spun.

The phosphorus-containing carboxylic acid represented by the above general formula used in the present invention has a molecular structure of PC as shown in the above formula.
It is symmetrical with a phosphine oxide skeleton of the bond, the two functional groups on the left and right are both carboxyl groups with equivalent frontier electron density, and various chemical reactions,
For example, the reaction rates of an esterification reaction, an amidation reaction, and the like are the same. Further, because of having a symmetrical structure, the heat resistance and mechanical properties of Compound A obtained by copolymerizing the compound are superior to those of the asymmetric copolymer, and the temperature is 200 to 300 ° C. which is applied in the production of polyester fiber. Moderately high temperatures are convenient for use in such processes.

The allyl group of the residue R in the above general formula is, for example, C ₆ H ₅ , C ₆ H ₄ -Me, C ₆ H _3- (Me) ₂ ,
C ₆ H ₄ —Et is exemplified, and aralkyl groups are, for example, C ₆ H ₅ —CH ₂ , C ₆ H ₄ (Me) —CH ₂ , C ₆ H
_{5 -CH 2 CH 2, C 6} H 3 - (Me) 2 , etc. -CH ₂ and the like. Among them, useful ones are a phenyl group and a toluyl group, and a phenyl group is most preferable because of its excellent heat resistance. The residue R ″ is H, CH _3. C ₂ H ₅ or more is not preferred because it causes steric hindrance.

Therefore, the phosphorus-containing dicarboxylic acid compound represented by the general formula (I) of the present invention is preferably bis- (2-carboxyethyl) phenylphosphine oxide, bis-
(2-carboxy-ipropyl) phenylphosphine oxide, bis- (2-carboxyethyl) m-toluylphosphine oxide, bis- (2-carboxy-i-propyl) m-toluylphosphine oxide, bis- (2
-Carboxyethyl) p-toluylphosphine oxide, bis- (2-carboxyethyl) xylylphosphine oxide, bis- (2-carboxyethyl) benzylphosphine oxide, bis- (2-carboxyi-propyl) benzylphosphine oxide, bis -(2-carboxyethyl) m-ethylbenzylphosphine oxide, and their cyclic acid anhydrides or their methyl esters, ethyl esters, propyl esters, butyl esters, ethylene glycol esters, propylene glycol esters, and butanediol Esters and the like.

[0015] These phosphorus-containing dicarboxylic acid compounds can be produced by adding an unsaturated compound to a P-substituted phosphine, or by adding a P-substituted dichlorophosphine or dichlorophosphine oxide to a Grignard reagent or an organic compound. There is a method of producing by reacting a metal compound. However, from the viewpoint of reaction yield, operability, quality, etc., the former method is preferred in which an unsaturated compound, for example, acrylonitrile, acrylic acid, acrylate, methyl methacrylate, or the like is added to the former P-substituted phosphine for production.

For example, bis- (2-carboxyethyl) phenylphosphine oxide is described in M.E. M. Rauhut,
I. Hechenbleikner, Helen A.
Currier, F.C. C. Schaefer and
V. P. Wystrach, J. et al. Am. Chem. S
oc. 81, 1103 to 1107 (1959), phenylphosphine is added with acrylonitrile, then oxidized and then alkali-hydrolyzed.

The compound A containing the compound represented by the general formula (I) may be a compound having any form and structure. For example, a compound reacted with an ester bond with another compound, a compound reacted with an amide bond, a compound reacted with a urethane bond, a compound reacted with an ether bond, and the like can be used.

As a substance to be ester-bonded, two O
It can be achieved by reaction with a compound having an H group. Preferably, adipic acid having the same skeletal structure as the polyester fiber, sebacic acid, azelaic acid, and other aliphatic dicarboxylic acids, and derivatives and ester derivatives thereof, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid,
Aromatic dicarboxylic acids such as 1,5-naphthalenedicarboxylic acid and 4,4-diphenyldicarboxylic acid; derivatives thereof; alkyl esters, allyl esters and ethylene glycol ester derivatives thereof.

The compound to be reacted by an amide bond can be achieved by reaction with a compound having two amino groups.

The composition is set so that the content of phosphorus atoms in compound A is at least 3% by weight, preferably 3.5% by weight, and more preferably 4 to 10% by weight. If the content of phosphorus atoms is less than 3% by weight, the amount of compound A to be blended in the polyester fiber to exhibit flame retardancy increases, resulting in thermal deterioration of the fiber, reduction in mechanical properties, and increase in coloring. Leads to.

If the polymerization degree of the compound A is too low, the heat resistance is inferior and when mixed with the polyester, the deterioration is remarkable.
On the other hand, if the polymerization degree is too high, there are disadvantages that large power and equipment are required for mixing, mixing cannot be sufficiently achieved, and the uniformity of fibers decreases. Preferably, the degree of polymerization is 5 or more, more preferably 10
~ 100. The degree of polymerization is appropriately selected according to the method of compounding the present compound A. For example, when polymerizing polyester,
When it is added at an early stage such as at the end of transesterification, the degree of polymerization is preferably 50 or less, and when blended after the middle stage of polyester polymerization, the degree of polymerization is preferably about 20 to 70.

As the fiber-forming polyester of the present invention, commonly used polyesters can be used. That is, a polyester obtained by copolymerization of a dicarboxylic acid or a derivative thereof described below with a glycol can be used.
For example, as a dicarboxylic acid component, 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, trans-hetisahydroterephthalic acid, and their ester-forming derivatives such as alkyl esters, aryl esters, ethylene glycol esters and the like. Particularly useful are terephthalic acid,
2.6-Naphthalenedicarboxylic acid as a main component, and one or more of these aromatic dicarboxylic acids and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, decamethylene dicarboxylic acid and other ester-forming derivatives. It can be used by mixing a small amount up to 10 mol%.

On the other hand, as glycol components, 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. Among them, useful ethylene glycol and 1.4-butanediol are used as main components, and one or more other glycol components and ester-forming derivatives may be used by mixing a small amount of up to 10 mol% of the diol component. it can.

An oxycarboxylic acid component having a carboxylic acid group and an alcohol group in one molecule, for example, 4-oxybenzoic acid, 4-hydroxyethoxybenzoic acid, oxypivalic acid and the like can be used if necessary.

If necessary, a small amount of a monofunctional compound such as benzoic acid, benzoylbenzoic acid, acetic acid, methoxypolyethylene glycol, or a compound having three or more functionalities,
For example, glycerin, pentaerythritol, phosphoric acid compounds and their ester-forming derivatives can be added.

The degree of polymerization of the polyester is not particularly limited as long as it is used for ordinary fibers. Preferably, the intrinsic viscosity [η] is 0.5 or more, and more preferably 0.6 to 0.6.
1.5, particularly preferably 0.65 to 1.0.

The compound A is incorporated into the polyester at the start of the polymerization of the fiber-forming polyester. Preferably,
It is carried out after completion of transesterification in which the terminal of dicarboxylic acid such as terephthalic acid is substituted by ethylene glycol. More preferably, it is added at the time when the polymerization of the polyester is not completed, for example, when the intrinsic viscosity [η] is 0.4 or less.

The compounding ratio of the compound A is not particularly limited as long as the mechanical properties, thermal properties, flame retardancy and the like of the flame-retardant fiber are not reduced. More preferably, it is 15% by weight or less.

In spinning, pigments, matting agents, fluorescent whitening agents, heat stabilizers, ultraviolet absorbers, antioxidants, antistatic agents, organic amines, organic carboxylic acid amides, etc. are used in the same manner as in the ordinary fiber spinning. Various ether bond inhibitors may be used as necessary.

The phosphorus-containing dicarboxylic acid component represented by the general formula (I) has a phosphorus atom content in the obtained polyester fiber of at least 2,000 ppm, preferably 3,000 to 20,000 ppm, more preferably 5,000 ppm.
000 to 15,000 ppm.
If it is less than 2,000 ppm, the flame retardancy is poor, and
If the content is more than 0 ppm, the flame retardant effect is saturated, and various properties inherent in the polyester are remarkably deteriorated.

The spinning can be carried out by a usual spinning method, but any of spin draw, high speed spinning and composite spinning can be adopted. The thickness of the fiber is usually 1 denier or more, but a finer fiber can be spun according to the application. Regarding the fiber cross section, not only a round cross section but also a modified cross section fiber such as a triangular cross section, a flat cross section, a square cross section, a polygonal cross section, a hollow cross section, etc. are possible.

[0032]

The flame-retardant polyester fiber of the present invention is obtained by adding a compound A, for example, a copolymer in which a phosphorus atom imparting flame retardancy is introduced into the main chain of the polyester during the polymerization of the polyester. There is a mixed state equivalent to that of complete copolymerization, and phosphorus atoms are very stabilized and contained in the fiber. Further, the flame retardancy can be easily adjusted by changing the addition rate of the copolymer, so that it is possible to easily respond to the size of production lots and the variety of varieties.

In terms of quality, it is a useful material having permanent properties such that it does not dissolve or fall off during fiber production or processing, use of the product, washing or the like, and the flame retardant performance does not decrease. Furthermore, the polyester has excellent light fastness, whiteness, and good dyeing properties without impairing the mechanical and thermal properties inherent in polyester and the texture of textile products. Further, the atom imparting flame retardancy is only a phosphorus atom, and even if the molded article comes in contact with a flame, no harmful gas is generated to the human body, and the safety is extremely high and is useful.

The flame-retardant polyester fiber obtained by the present invention can be spun, drawn, and post-processed into fibers and yarns by a usual method, and weaving and knitting can be carried out by ordinary looms without special consideration. , A knitting machine can be used. High-level technology such as spinning mixed with ordinary polyester or cationic dyeable polyester, or composite spinning, composite weaving with the ordinary fibers or other fibers such as cotton or acrylic, or multi-layer woven fabric; High quality flame retardant polyester products can be obtained. Such textile products include, for example, thick fabrics, clothing, carpets, curtains, and socks.

As described above, various flame-retardant fibers and high-performance flame-retardant fibers can be produced industrially easily and inexpensively by the method of the present invention, which is very useful.

[0036]

EXAMPLES The method of the present invention and its operation and effect will be described more specifically with reference to the following examples. In the examples, “parts” means “parts by weight”. The intrinsic viscosity “η” is 20 in a mixed solvent of phenol / tetrachloroethane = 6/4.
It was determined by a conventional method at ° C. The melting point was determined from the endothermic peak of DSC. In addition, the evaluation of flame retardancy was measured and shown according to the number of times of flame contact (JIS L-1091 D) or the limiting oxygen index (JIS K-7201) method using a 45 ° coil method.

Embodiment 1

Bishydroxyethyl terephthalate (BH
ET) 70 parts, the above bis- (2,2'-carboxyethyl) phenylphosphine oxide 30 parts, and tetrabutoxytitanate 0.03 part were thrown into a polymerization vessel, melted, and then gradually heated to reduce the internal pressure. Finally 255 ℃, 0.3m
Polycondensation was performed at mHg for 3 hours. Next, the polymer was extruded in a cord shape and cut into pellets having a size of 2.5 mmφ × 3 mm to obtain a compound A having a phosphorus content of 3.8% by weight. Next, bishydroxyethyl terephthalate was used as a starting material, and antimony trioxide was used as a polymerization catalyst.
After heating and melting at 0 ° C., the internal pressure was reduced while gradually increasing the temperature. Finally, polycondensation was performed at 250 ° C. and 0.3 mmHg for 3 hours, and the rise of the melt viscosity [η] was monitored by the rotation torque of the stirrer. While the polymerization was continued. When the intrinsic viscosity [η] reaches 0.2 on the way, the above compound A is added to the final polymer in an amount shown in Table 1 to continue the polymerization, and the content is adjusted to a predetermined viscosity (intrinsic viscosity [η] = 0). .62), the content was extruded into a cord shape and cut into pellets of 2.5 mmφ × 3 mm.

After the pellets were dried to a moisture content of 0.005%, they were melt-spun with an extruder at a spinning temperature of 288 ° C. and a take-up speed of 800 m / min, followed by a magnification of 3.9.
The film is stretched with a roller heater at 75 ° C. at a stretching speed of 1000 m / min and set with a plate heater at 150 ° C.
A d / 24f drawn yarn was obtained. Yarn quality is 4.7-5.8
g / d and elongation of 30 to 45% were good.

Two stretched yarns were combined, knitted and refined by a cylinder knitting machine, and tested for flame retardancy. In the flame retardancy test, the tubular knitted product was cut out so as to have a weight of 1 g and a length of 100 mm, and the number of times of flame contact by a 45 ° coil method was determined. The results are shown in Table 1.

[0041]

[Table 1]

Example 2 A copolymer containing 4% by weight of various phosphorus-containing compounds shown in Table 2 was obtained, and the phosphorus content in the final polymer was 6500 ppm during the polymerization of the polyester in the same manner as in Example 1. The polymerization was completed, and the polymer was recovered and spun in the same manner as in Example 1 to obtain a 75d / 24f flame-retardant polyester fiber. Table 2 shows the performance of various compounds.

[0043]

[Table 2]

[0044]

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[0045]

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[0046]

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[0047]

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[0048]

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[0049]

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[0050]

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Continuation of the front page Examiner Shigemi Sawamura (56) References JP-A-5-51440 (JP, A) JP-A-50-82149 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) ) D01F 6/84 306 C08G 63/692

Claims (4)

(57) [Claims] 1. A compound of the general formula (In the formula, R represents an allyl group having 6 to 9 carbon atoms, an aralkyl group, R ′ represents H or an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, and R ″ represents H or a methyl group.) The compound A, which is derived from at least one of the phosphorus-containing dicarboxylic acid compounds or derivatives thereof and has a phosphorus content of at least 3% by weight, has a phosphorus atom content of at least 20% at the time of polymerization of the fiber-forming polyester.
A method for producing a flame-retardant polyester fiber, characterized in that it is blended so as to be 00 ppm, polymerized, and then spun. 2. The method for producing a flame-retardant polyester fiber according to claim 1, wherein the compound A is a copolymer having an ester bond. 3. The method for producing a flame-retardant polyester fiber according to claim 1, wherein the compound A is blended after the transesterification of the fiber-forming polyester is completed. 4. The method for producing a flame-retardant polyester fiber according to claim 1, wherein the compound A is compounded at a time when the intrinsic viscosity [η] of the fiber-forming polyester during polymerization does not exceed 0.4.