JP2005120254A - Method for producing flame-retardant polyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently producing a polyester, of which the polymerization reactivity is high and which gives a product good in hue, free from smoking at spinning and excellent in flame-retardancy. <P>SOLUTION: The method for producing the flame-retardant polyester is characterized in adding all of the phosphorus compounds represented by formulae (1)-(4) wherein the total content of phosphorus compounds represented by formulae (3) and (4) is ≤25.0 wt.%, to the polyester reaction system so as to obtain the polyester containing 0.05-5 wt.% of a phosphorus atom therein [in formulae (1)-(4), R<SB>1</SB>is a 1-18C alkyl group or an aryl group]. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a flame retardant polyester. More specifically, the present invention relates to a method for efficiently producing a polyester excellent in flame retardancy because of good polymerization reactivity and color tone, no smoke generation during spinning, and high phosphorus residual ratio.

  Polyester is used for various purposes because of its useful functionality, and is used for clothing, materials, and medical use, for example. Among them, polyethylene terephthalate is excellent in terms of versatility and practicality and is preferably used, but it is desired to impart flame retardancy to various polyester molded articles from the viewpoint of fire prevention and the like. In particular, polyester fibers are widely used in clothing, bedding, curtains, carpets, and the like, but since they are insufficient in terms of flame retardancy, various efforts have been made to improve this point.

  Conventionally, as a method for imparting flame retardancy to polyester, (1) a method in which a flame retardant is attached to the surface of a molded article or a soaked inside (post-processing method), Alternatively, methods such as a method of kneading at the time of molding (blending method), (3) a method of adding a flame retardant during the production of polyester and copolymerizing the same (copolymerization method) have been proposed.

  Among these methods, the post-processing method has drawbacks that the texture becomes rough, and the flame retardant drops off due to washing and friction, resulting in a decrease in performance. Further, in the blending method, the flame retardant oozes out in the manufacturing process of the molded product, causing trouble. On the other hand, a method of copolymerizing a flame retardant at the time of polymer production can overcome the above-mentioned drawbacks, and therefore has the highest industrial value and is a method that is preferably used.

  On the other hand, as a flame retardant that can be used in the copolymerization method, halogen compounds and phosphorus compounds having an ester-forming functional group are known, but a molded product with little coloration and excellent light resistance can be obtained, and combustion Phosphorus compounds are superior because sometimes no toxic gases are generated.

  As a phosphorus compound used in this copolymerization method, there is a method using a phosphate ester (Patent Document 1). However, in this method, if the amount added is increased, polyester gelation occurs due to three-dimensionalization. There is a problem that it cannot be copolymerized. In addition, there is a method using a phosphonic acid compound (Patent Document 2), but there is a problem that a phosphorus compound is scattered during production of a polymer and the phosphorus compound cannot be copolymerized in a large amount due to low polymerization reactivity.

Furthermore, a method of copolymerizing a phosphinic acid compound (Patent Document 3, Patent Document 4), a method of copolymerizing a phosphinic acid compound containing a low-purity phosphine compound and / or a phosphonous acid compound (Patent Document 5), A method of copolymerizing an organophosphorus compound having the chemical structure (Patent Document 6) and the like are also disclosed. Although these methods are advantageous in that there are few problems such as the above-mentioned three-dimensionalization and scattering, there is a problem that the polymerization reaction is delayed, the color of the resulting polymer is yellowish, and smoke is generated during spinning. In addition, further improvement has been demanded for improvement in flame retardancy.
Japanese Patent Publication No. 38-7244 Japanese Patent Publication No. 36-20771 Japanese Patent Laid-Open No. 50-56488 JP-A-7-102418 JP-A-6-287414 Japanese Patent Publication No. 55-41610

  The object of the present invention is to solve the above-mentioned conventional problems, not only have good polymerization reactivity and color tone, but also produce a polyester excellent in flame retardancy because it does not emit smoke during spinning and has a high phosphorus residual ratio. It is to provide a method of manufacturing.

  In order to solve the above-mentioned problems, the present inventors have produced a polyester using a dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative as main starting materials. And a phosphorus compound in which the total ratio of the formulas (3) and (4) is 25.0% by weight or less is contained in an amount of 0.05 to 5% by weight as phosphorus atoms with respect to the obtained polyester. It can be achieved by a method for producing a flame retardant polyester characterized in that it is added to a polyester reaction system.

（ここで、式（１）〜式（４）のＲ₁ は炭素数１〜１８のアルキル基、アリール基を表す。）

(Here, R ₁ in formula (1) to formula (4) represents an alkyl group having 1 to 18 carbon atoms or an aryl group.)

  Since the polymerization reactivity and color tone are good, there is no smoke during spinning, and the phosphorus residual ratio is high, it is possible to efficiently produce a polyester excellent in flame retardancy.

  The polyester of the present invention is synthesized from a dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. Specific examples of dicarboxylic acids or ester-forming derivatives thereof include terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, adipic acid, sebacic acid, 5-sodium sulfoisophthalic acid, 4,4′-diphenyldicarboxylic acid And dicarboxylic acids such as cyclohexanedicarboxylic acid and ester-forming derivatives thereof. Two or more of these may be used in combination, but it is preferable from the viewpoint of heat resistance to use 80 mol% or more based on the total dicarboxylic acid component in the polyester from which terephthalic acid and ester-forming derivatives thereof can be obtained. Specific examples of the diol and its ester-forming derivative include dioxy compounds such as ethylene glycol, tetramethylene glycol, polyethylene glycol, hexamethylene glycol, neopentyl glycol, polypropylene glycol, and cyclohexanedimethanol. . Two or more of these may be used in combination, but it is preferable from the viewpoint of heat resistance to use 80 mol% or more based on the total dicarboxylic acid component in the polyester from which ethylene glycol can be obtained.

  The polyester of the present invention is produced by esterifying these raw materials when dicarboxylic acid and diol are the main starting materials, or transesterifying when using a lower ester compound of dicarboxylic acid and diol as the starting materials. After the polymer is synthesized, the low polymer is further produced by polycondensation reaction under high temperature and reduced pressure.

  In the present invention, a phosphorus compound of formula (1) to formula (4) is added, and the total proportion of the phosphorus compounds of formula (3) and formula (4) is 25.0% by weight or less. On the other hand, it is added to the reaction system so as to contain 0.05 to 5% by weight as phosphorus atoms.

（ここで、式（１）〜式（４）のＲ₁ は炭素数１〜１８のアルキル基、アリール基を表す。）
式（１）で示されるリン化合物としては具体的には、下記式（５）〜式（８）等のホスフィン酸化合物を挙げることができ、これらの２種以上からなってもよい。

(Here, R ₁ in formula (1) to formula (4) represents an alkyl group having 1 to 18 carbon atoms or an aryl group.)
Specific examples of the phosphorus compound represented by the formula (1) include phosphinic acid compounds such as the following formulas (5) to (8), and may be composed of two or more of these.

また、式（２）で示されるリン化合物として具体的には、式（９）〜式（１２）等のホスフィン酸化合物を挙げることができ、これらの２種以上からなってもよい。

Specific examples of the phosphorus compound represented by the formula (2) include phosphinic acid compounds such as the formulas (9) to (12), and may be composed of two or more of these.

さらに、式（３）で示されるリン化合物として具体的には、式（１３）〜式（１６）等のホスフィン酸化合物を挙げることができ、これらの２種以上からなってもよい。

Furthermore, specific examples of the phosphorus compound represented by the formula (3) include phosphinic acid compounds such as the formulas (13) to (16), and may be composed of two or more of these.

また、式（４）で示されるリン化合物として具体的には、式（１７）〜式（２０）等のホスフィン酸化合物を挙げることができ、これらの２種以上からなってもよい。

Specific examples of the phosphorus compound represented by the formula (4) include phosphinic acid compounds such as the formulas (17) to (20), and may be composed of two or more of these.

なかでも、ポリエステルの重縮合時における粘度上昇が比較的速やかであること、得られるポリエステルの機械的物性低下が少ないことなどから、式（１）〜式（４）で示されるリン化合物におけるＲ₁ は、炭素数１〜６のアルキル基またはフェニル基であるホスフィン酸化合物が好ましい。

Among these, the R ₁ in the phosphorus compounds represented by the formulas (1) to (4) has a relatively rapid increase in viscosity during the polycondensation of the polyester and the mechanical properties of the resulting polyester are small. Is preferably a phosphinic acid compound which is an alkyl group having 1 to 6 carbon atoms or a phenyl group.

  The total content of the phosphorus compound formulas (3) and (4) used in the present invention needs to be 25.0% by weight or less. When the content is 25.0% by weight or less, the polymerization reaction is not delayed and the color of the polymer is good, and there is no smoke during spinning, and 18.0% by weight or less is more preferable. As the total content of the phosphorus compound formulas (3) and (4) increases, the polymerization reaction is delayed, the color tone of the polymer is deteriorated, and further, smoke is generated during spinning. The cause of this is not clear, but the polyester polymerization reaction Among the phosphorus compounds added to the system, particularly, the formula (3) and the formula (4) are more likely to cause coloring components during the polymerization reaction than the phosphorus compounds of the formula (1) or the formula (2). Since the polymerization reactivity is inferior, it is presumed that components mainly composed of the formula (3) and the formula (4) remaining in the polymer after the polyester polymerization cause a smoke generation phenomenon during spinning.

  It should be noted that the content of both the phosphorus compounds of formula (3) and formula (4) is less than 0.1% by weight can be obtained stably unless complicated purification operations such as distillation and recrystallization are performed. Since it cannot be used, it is not preferable from the viewpoint of efficiency.

  The phosphorus compound used in the present invention needs to be added so as to contain 0.05 to 5% by weight, preferably 0.1 to 3% by weight, in terms of phosphorus atom, with respect to the polyester obtained. When the content is 0.05% by weight or more, sufficient flame retardancy is exhibited. Further, if it is 5% by weight or less, it is preferable that there is no delay during the polymerization reaction and no deterioration in physical properties of the polyester, and no deterioration in operability when producing polyester fibers.

  By adding the phosphorus compounds of the formulas (1) to (4) of the present invention in the following proportions, there is no smoke during spinning, the residual ratio of phosphorus in the polyester is increased, and the flame retardancy is further improved. To preferred.

Formula (1) 45.0-75.0 weight%
Formula (2) 15.0-45.0 weight%
Formula (3) 0.1-20.0 weight%
Formula (4) 0.1-5.0 wt%
Among these, the addition ratios of the formulas (1) to (4) in the phosphorus compound are more preferably the following because there is no delay in the polymerization reaction and the copolymerization is stable.

Formula (1) 50.0-70.0 weight%
Formula (2) 20.0-35.0 weight%
Formula (3) 0.1-15.0 weight%
Formula (4) 0.1-3.0 wt%
In addition, you may use together phosphorus compounds other than the phosphorus compound represented by Formula (1)-Formula (4) used in this invention, and you may add to the reaction system of polyester.

  The phosphorus compounds of the formulas (1) to (4) used in the present invention have a coloring degree (APHA) of 50 or less after heat treatment at 165 ° C. for 5 hours as a mixture of the formulas (1) to (4). It is preferable because the color tone of the polymer obtained is good. If the heat resistance of the phosphorus compound is inferior, coloration occurs, but this causes impurities and colorable substances to be generated by heat treatment, and the color tone of the polymer is further deteriorated because coloration is increased particularly in a polymerization reaction system in a high temperature field. It is considered a thing. From such a viewpoint, the coloring degree (APHA) of the phosphorus compound mixture after the heat treatment is more preferably 30 or less.

  The timing of addition of the phosphorus compound to the reaction system in the present invention described above may be arbitrary. Since the scattering of the added phosphorus compound into the reaction system is relatively small and the polymerization time is relatively short, the transesterification reaction or It is preferable to add from the start of the esterification reaction until the polymerization reaction proceeds until the intrinsic viscosity of the reaction product reaches 0.3.

  In addition, the phosphorus compounds of the formulas (1) to (4) used in the present invention may be added individually, but may be added to the reaction system as a mixture as they are, or a slurry dispersed in glycol or It may be added to the reaction system in the form of a solution diluted with glycol.

  In the polyester of the present invention, a conventionally known esterification or transesterification catalyst, ether bond formation inhibitor, anti-coloring agent, matting agent, ultraviolet absorber, coloring agent, crystallization accelerator and the like until the polymerization reaction is completed. It can also be added at any stage.

   The flame-retardant polyester of the present invention is made into a woven fabric, net, sheet, etc., and is used for industrial materials such as curing mesh sheets, safety nets, ropes, interiors such as curtains, chair tension, bedding, etc. .

Hereinafter, the present invention will be described in more detail with reference to examples. In addition, each characteristic value in an Example was measured by the method described below.
(1) Phosphorus compound mixture composition Determined by 1H-NMR and 31P-NMR.
(2) Degree of coloring (APHA)
The phosphorous compound mixture is placed in a 100 ml marked colorimetric tube up to the marked line and immersed in an oil bath adjusted to 165 ± 0.5 ° C. In order to eliminate the influence of oxygen in the air, the colorimetric tube was slightly pressurized (1 × 10 ⁵ Pa gauge pressure) with nitrogen gas for 5 hours, then immediately removed from the colorimetric tube and wiped off the adhering oil. Thereafter, the degree of coloration (APHA) after the heat treatment was determined by comparison with the hue of the standard solution (JIS K1527-1978).
(3) Intrinsic viscosity IV
Measurement was performed at 25 ° C. using orthochlorophenol as a solvent.
(4) Phosphorus element content in polyester It calculated | required with the fluorescent-X-ray elemental-analysis apparatus (The Horiba Ltd. make, MESA-500W type | mold).
(5) Color tone Using a color difference meter (SM color computer model SM-3) manufactured by Suga Test Instruments Co., Ltd., it was measured as a Hunter value. The L value represents whiteness, and the yellow value becomes stronger as the b value increases.
(6) Strength and elongation of drawn yarn Using a Tensilon tensile tester manufactured by Toyo Bodwin, the SS curve was obtained at a sample length of 25 cm and a tensile speed of 30 cm / min, and the high elongation was calculated.
(7) Flame retardant performance of the fiber When the yarn is used as a tubular knitted fabric, 1 g of it is inserted into a 10 mm long wire coil, held at an angle of 45 degrees, ignited from the lower end, and fire extinguished away from the fire source By repeating the ignition again, the number of ignition times required to burn out all the samples was obtained and expressed as the average number of ignition times measured for five samples. Passing 3 or more times of flame contact.

Number of flame contact: 5 times or more ◎
3 to less than 5 times ○
Less than 3 times ×
Example 1
A slurry of 100 kg of high-purity terephthalic acid (manufactured by Mitsui Chemicals) and 45 kg of ethylene glycol (manufactured by Nippon Shokubai Co., Ltd.) is charged with about 120 kg of bis (hydroxyethyl) terephthalate in advance, at a temperature of 250 ° C. and a pressure of 1.2 × 10 ⁵ Pa. The esterification reaction vessel held in the vessel was sequentially supplied over 4 hours, and after completion of the supply, the esterification reaction was carried out over an additional hour, and 107 kg of this esterification reaction product was transferred to the polycondensation vessel. Subsequently, a mixture of phosphorous compounds (formula (5) 61.3 wt%, formula (9) 27.5 wt%, formula (13) 10.4 wt%, Formula (17) 0.8 wt%, coloring degree (APHA) 10) is added to the reaction system so as to be 1.0 wt% as a phosphorus atom with respect to the produced polymer, stirred for 10 minutes, and then used as a polycondensation catalyst. Antimony trioxide (0.045% by weight based on the resulting polymer) was added. Thereafter, while stirring the low polymer at 30 rpm, the reaction system was gradually heated from 250 ° C. to 290 ° C. and the pressure was lowered to 40 Pa. The time to reach the final temperature and final pressure was both 60 minutes. When the predetermined stirring torque was reached, the reaction system was purged with nitrogen, returned to normal pressure, the polycondensation reaction was stopped, discharged into cold water in a strand form, and immediately cut to obtain pellets. The time from the start of decompression to the arrival of the predetermined stirring torque (polymerization time) was 2 hours and 45 minutes.

  The polyester pellets obtained had an intrinsic viscosity of 0.74, a color tone L value of 53.1, a b value of 4.3, and a phosphorus element content of 0.974% by weight (phosphorus element residual ratio 97.4%). Met.

  After drying the pellet, solid state polymerization was performed at 210 ° C. to obtain a chip having an intrinsic viscosity of 1.04. This solid state polymerization chip was supplied to an extruder type spinning machine and melt-spun at a spinning temperature of 300 ° C. At this time, a metal nonwoven fabric having an absolute filtration diameter of 15 μm was used as a filter, and a 0.6 mmφ round hole was used as the base. Subsequently, the film was subjected to a drawing heat treatment at a temperature of 250 ° C., and then subjected to a relaxation treatment to wind up to obtain a drawn yarn of 1100 dtex 144 filaments. There was almost no fuming during spinning, and there was no yarn breakage, increased filtration pressure, and no yarn breakage during drawing. The drawn yarn had a strength of 7.3 cN / dtex and an elongation of 18%, and had good physical properties. Further, the average number of ignition times of the drawn yarn was 5.5 times, and the flame retardant performance was good.

Examples 2 to 7 and Comparative Example 1
Examples 2 to 8 are the same as Example 1 except that the mixture of phosphorus compounds (formula (5), formula (9), formula (13), formula (17)) is different. Polymerization was performed, and spinning / stretching was performed using a chip after solid-phase polymerization.

As apparent from Table 1, Examples 2 to 8 satisfying the scope of the present invention all had good polymerization reactivity, and the obtained polyester pellets had good color tone b value.
Further, there was no problem in spinning / drawing properties and fiber properties, and the flame retardancy was excellent. In addition, although Example 4 with much total content of Formula (13) and Formula (17) showed a little smoke generation at the time of spinning, it is in a tolerance | permissible_range.

  On the other hand, as shown in Table 2, among the compositions in the phosphorus compound mixture, Comparative Example 1 using the total amount of the formula (13) and the formula (17) is outside the scope of the present invention has a delay during polymerization. The color tone of the obtained polyester pellets was strongly yellowish.

Examples 9-12 and Comparative Examples 2-3
Polymerization was carried out in the same manner as in Example 1 except that the addition amount of the mixture of phosphorus compounds (Formula (5), Formula (9), Formula (13), Formula (17)) was changed, and solid phase polymerization was performed. The later chip was used for spinning and drawing. As is clear from Table 1, in Examples 9 to 12 that satisfy the scope of the present invention, the polymerization reactivity was good, and the color tone of the obtained polyester pellets was also good. Further, there was no problem in spinning / drawing properties and fiber properties, and the flame retardancy was excellent.

  On the other hand, as shown in Table 2, Comparative Example 2 with a small amount of phosphorus compound added had poor polymerization performance and color tone of the polyester pellets, but was inferior in flame retardancy. Further, in Comparative Example 3 having a large amount of phosphorus compound to be added, a delay was observed during the polymerization reaction, and the color tone of the obtained polyester pellets was yellowish, and the fiber strength was inferior.

Examples 13 and 14
Polymerization was carried out in the same manner as in Example 1 except that a mixture of phosphorus compounds having different coloring degrees (APHA) after heat treatment was used, and spinning and stretching were performed using a solid-phase polymerized chip. As is apparent from Table 2, the polymerization reactivity in Examples 13 and 14 satisfying the scope of the present invention was good, and the color tone of the obtained polyester pellets was slightly yellowish. Also, there was no problem with spinning / drawing properties and fiber properties, and the flame retardancy was excellent.

Example 15 and Comparative Example 4
Changed the type of mixture of phosphorus compounds (formula (6), formula (10), formula (14), formula (18
Except for the above, polymerization was carried out in the same manner as in Example 1, and spinning / stretching was performed using a solid-phase polymerized chip. As apparent from Table 3, Example 15 satisfying the scope of the present invention had good polymerization reactivity, and the color tone of the obtained polyester pellets was also good. Moreover, it was excellent in flame retardancy.

  On the other hand, in Comparative Example 4 in which the total amount of Formula (14) and Formula (18) in the phosphorus compound mixture was outside the scope of the present invention, polymerization delay was observed, and the color tone of the obtained polyester pellets was yellowish Was strong.

Comparative Examples 5 and 6
Polymerization was carried out in the same manner as in Example 1 except that the addition amount of the mixture of phosphorus compounds (formula (6), formula (10), formula (14), formula (18)) was changed, and solid phase polymerization was performed. The later chip was used for spinning and drawing. As shown in Table 3, Comparative Example 5 with a small amount of phosphorus compound added had good polymerization reactivity and good color tone of the polyester pellets, but had poor flame retardancy.

  Moreover, the comparative example 6 with much phosphorus content showed the delay at the time of a polymerization reaction, the color tone of the obtained polyester pellet was yellowish, and the intensity | strength of the fiber was inferior.

Claims (5)

In producing a polyester using a dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative as a main starting material, the polyester includes any of the formulas (1) to (4), and the formulas (3) and ( A flame retardant characterized by adding a phosphorus compound having a total ratio of 4) of 25.0% by weight or less to a polyester reaction system so as to contain 0.05 to 5% by weight as a phosphorus atom with respect to the obtained polyester. Method for producing reactive polyester.

(Here, R ₁ in formula (1) to formula (4) represents an alkyl group having 1 to 18 carbon atoms or an aryl group.)   The method for producing a flame-retardant polyester according to claim 1, wherein the phosphorus compounds of the formulas (1) to (4) are added as a mixture. The method for producing a flame-retardant polyester according to claim 1 or 2, wherein the ratio of the phosphorus compound represented by formula (1) to formula (4) is as follows.
Formula (1) 45.0-75.0 weight%
Formula (2) 15.0-45.0 weight%
Formula (3) 0.1-20.0 weight%
Formula (4) 0.1-5.0 wt% The method of producing a flame-resistant polyester according to any one of claims 1 to 3, characterized in that R ₁ of formula (1) to (4) is an alkyl group, or a phenyl group having 1 to 6 carbon atoms.   5. The degree of coloration (APHA) after heat treatment at 165 ° C. for 5 hours as a mixture of the phosphorus compounds of the formulas (1) to (4) is 50 or less. A method for producing the flame retardant polyester described in the item.