JP2006169358A - Flame-retardant polyester for fiber and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester having no coloration problem and excellent flame retardancy and being applicable to fibers for clothing, fibers for industrial materials, and like things. <P>SOLUTION: The flame-retardant polyester for the fibers is a polyester based on ethylene terephthalate units and is characterized by containing a copolymerized organophosphorus compound (1) in an amount of 500 to 15,000 ppm in terms of a phosphorus content in the polyester, containing a 100-400 ppm solid solution comprising an aluminum compound and a magnesium compound, and having a limiting viscosity of less than 0.6 and an L value in the Hunter's Lab color space of less than 50. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fiber polyester excellent in flame retardancy and a method for producing the same.

  Polyester, especially polyethylene terephthalate (hereinafter abbreviated as PET), because of its excellent mechanical and chemical properties, in addition to fibers for clothing and industrial use, films or bottles for magnetic tape, capacitors, etc. It is widely used for moldings. In recent years, there has been an increasing demand for flame retardancy of synthetic fibers and various plastic products from the viewpoint of fire prevention.

  Conventionally, various attempts have been made to impart flame retardancy to polyester, and a method of containing a phosphorus compound is considered to be effective. Various phosphorus compounds have been proposed. Among them, the organic phosphorus compound (2) represented by the following general formula [2] is excellent in terms of flame retardancy. However, when an antimony compound represented by antimony triacid, which is a general polyester polymerization catalyst, is used for this organophosphorus compound, antimony trioxide is converted into antimony metal insoluble in polyester by reaction with the antimony compound. Due to the reduction, there is a problem in that the polymerizability is lowered during the polymerization reaction, a polyester having a target intrinsic viscosity cannot be obtained, and the polyester is colored black by metal antimony.

Therefore, by using germanium oxide instead of antimony trioxide, the reaction with the phosphorus compound is not carried out and the coloring of the polyester is improved, but there is a problem that the cost of germanium oxide is very high. (Patent Document 1)
Japanese Unexamined Patent Publication No. 01-284521

  In view of the present situation as described above, an object of the present invention is to provide a polyester for fibers that has no problem of coloring and is excellent in flame retardancy.

The present invention solves the above-mentioned problems and has the following contents.
1. It is a polyester having ethylene terephthalate units as a main component, and an organic phosphorus compound (1) represented by the following general formula [1] is copolymerized so that the phosphorus atom content in the polyester is 500 to 15000 ppm. A flame-retardant polyester for fibers, comprising 100 to 400 ppm of a solid solution composed of a compound and a magnesium compound, having an intrinsic viscosity of 0.6 or more and an L value in Hunter's Lab color method of 50 or more.

(In the formula, X represents an alkyl group in which two or more of the hydrogen atoms of the alkyl group are substituted with a carboxyl group.)
2. In the method for producing a polyester mainly composed of an ethylene terephthalate unit, an organic phosphorus compound (2) obtained by reacting an organic phosphorus compound (2) represented by the following general formula [2] with an aliphatic unsaturated dicarboxylic acid ( 1) is added, and a polycondensation reaction is performed using a solid solution composed of an aluminum compound and a magnesium compound as a polycondensation catalyst.

  By using a solid solution of a magnesium compound and an aluminum compound as the polycondensation catalyst, the polyester of the present invention can obtain a combined effect of the magnesium compound and the aluminum compound and obtain an appropriate polymerization activity. In addition, since the magnesium compound and aluminum compound solid solution does not react with the phosphorus compound used as a flame retardant component, there is no coloration or dullness as in the case of using an antimony catalyst, and a polyester with good flame retardancy is used. Obtainable.

  Hereinafter, the present invention will be described in detail.

  In the polyester of the present invention, an ethylene terephthalate unit is a main component. The ratio of the ethylene terephthalate unit is not particularly specified, but is preferably 80 mol% or more.

  It is necessary for the polyester of the present invention that the organophosphorus compound (1) represented by the following general formula [1] is copolymerized so that the content of phosphorus atoms in the polyester is 500 to 15000 ppm, preferably Is 1000-10000 ppm.

(In the formula, X represents an alkyl group in which two or more of the hydrogen atoms of the alkyl group are substituted with a carboxyl group.)

  When the copolymerization ratio of the organophosphorus compound (1) is less than 500 ppm as the phosphorus atom content, sufficient flame retardancy cannot be obtained. On the other hand, if it exceeds 15000 ppm, the polymerizability of the polyester deteriorates, making it difficult to sufficiently increase the degree of polymerization.

  As a method of copolymerizing the organophosphorus compound (1) with polyester, an organophosphorus compound is prepared by reacting an organophosphorus compound (2) represented by the following formula [2] with an aliphatic unsaturated dicarboxylic acid in advance. After (1), it is preferably added to the reaction system.

  Specific examples of the aliphatic unsaturated dicarboxylic acid include fumaric acid, maleic acid, mesaconic acid, citraconic acid, glutaconic acid, itaconic acid and the like, or anhydrides thereof and ester compounds thereof. Itaconic acid.

  The reaction conditions of the organophosphorus compound (2) and the aliphatic unsaturated dicarboxylic acid are not particularly specified, but the aliphatic unsaturated dicarboxylic acid is 1.0 to 1.05 with respect to the organophosphorus compound (2). The reaction rate is 100% to 150 ° C. for 1 to 10 hours in an ethylene glycol solution, and the reaction rate between the organophosphorus compound (2) and the aliphatic unsaturated dicarboxylic acid in the reaction solution is It is preferably 90% or more.

  The polyester of the present invention may contain a copolymer component other than the organic phosphorus compound (1) and the aliphatic unsaturated dicarboxylic acid as long as the effects of the present invention are not impaired. Examples of such copolymer components include aromatic dicarboxylic acid components such as isophthalic acid, phthalic anhydride, and naphthalenedicarboxylic acid, saturated succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, dimer acid, and the like. Aliphatic dicarboxylic acid component, 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol , Aliphatic glycol components such as 1,4-butylene glycol, alicyclic glycol components such as 1,4-cyclohexanedimethanol, polyalkylene ether components such as polyethylene glycol, and alkylene oxide adducts of bisphenol A and bisphenol S Aromatic glycol component, 4-hydroxybenzoic acid, a hydroxycarboxylic acid component such as ε- caprolactone.

  In the polyester of the present invention, it is necessary to contain 100 to 400 ppm of a solid solution composed of an aluminum compound and a magnesium compound. A solid solution composed of an aluminum compound and a magnesium compound is a solid in which they are dissolved to form a uniform phase, and is used as a polycondensation catalyst. When the content is less than 100 ppm, it is difficult to sufficiently increase the degree of polymerization because of low polymerizability. If the content exceeds 400 ppm, not only the polymerizability is saturated, but the color tone of the resulting polyester is lowered.

  Examples of aluminum compounds that form solid solutions include aluminum acetate, carboxylates such as aluminum benzoate, inorganic acid salts such as aluminum chloride and aluminum carbonate, aluminum chelate compounds such as aluminum methoxide, aluminum hydroxide, aluminum oxide, Examples include inorganic acid salts such as metallic aluminum. Of these, carboxylates and inorganic acid salts are preferred, and among these, aluminum hydroxide, aluminum acetate, and aluminum chloride are particularly preferred.

  Moreover, as a magnesium compound which forms a solid solution, magnesium hydroxide, magnesium carbonate, magnesium acetate, carboxylates other than acetic acid, etc. are mentioned, Especially magnesium hydroxide and magnesium carbonate are preferable.

  Moreover, in the solid solution contained in the polyester of the present invention, metals other than magnesium and aluminum or compounds thereof may be contained. Other metals include zinc, titanium, tin, cobalt, manganese, and the like.

  The intrinsic viscosity of the polyester of the present invention needs to be 0.6 or more. If it is less than 0.6, it cannot be processed into a fiber or the like, or the strength after processing becomes insufficient.

  It is necessary that the L value in the Lab colorimetric method of the polyester hunter of the present invention is 50 or more. When the L value is less than 50, when used as a fiber, the blackness is too strong to be used practically.

  In addition, the polyester of the present invention includes antioxidants such as hindered phenol compounds, color improvers such as cobalt compounds, fluorescent agents, and dyes, and titanium dioxide as long as the object of the present invention is not impaired. Additives such as pigments and light resistance improvers such as cerium oxide may be added.

  The polyester of the present invention can be produced, for example, by the following method.

  Under an ethylene glycol solvent, the organophosphorus compound (2) and the aliphatic unsaturated dicarboxylic acid are adjusted to a ratio of 1.0 to 1.05 times equivalent of the aliphatic unsaturated dicarboxylic acid to the organophosphorus compound (2), It is set as the organophosphorus compound (1) by making it react at reaction temperature 100 to 150 degreeC for 1 to 10 hours.

  Next, a slurry of terephthalic acid and ethylene glycol is continuously supplied to an esterification reaction vessel in which bis (β-hydroxyethyl) terephthalate and its low polymer are present, and the temperature of 250 ° C. is about 3 to 8 hours. By reacting, a polyester oligomer having an esterification reaction rate of about 95% is continuously obtained. This was transferred to a polymerization can, an ethylene glycol solution of the above organophosphorus compound (1) was added, and depolymerization was performed at a temperature of 230 to 260 ° C. for 0.5 to 2 hours, and then an aluminum compound as a polycondensation catalyst. And a solid solution composed of magnesium compound is added to start a polycondensation reaction, and the internal temperature is raised to a predetermined temperature after the reaction starts.

  The polycondensation reaction is usually preferably carried out under a reduced pressure of about 0.12 to 12 hPa at a temperature of 250 to 290 ° C. until the intrinsic viscosity becomes 0.6 or more.

  The polyester of the present invention can be used for various applications such as fibers, films, and molding.

  Next, the present invention will be described specifically by way of examples.

In addition, the characteristic of polyester shown in the Example and the comparative example was measured or evaluated by the following method.
(1) Intrinsic viscosity [η]
The measurement was performed at a temperature of 20 ° C. using a mixture of equal mass of phenol and tetrachloroethane as a solvent.
(2) Color tone of polyester (L value, b value)
Measurement was performed using a color difference meter ND-Σ80 manufactured by Nippon Denshoku Industries Co., Ltd. The color tone was determined using a Hunter Lab colorimeter. The L value represents white-black (+ is white,-is black), and the b value is yellow-blue (+ is yellow,-is blue). If the L value is 50 or more and the b value is 10 or less, it is acceptable.
(3) Content of phosphorus atom and solid solution Quantification was performed by a fluorescent X-ray method using a fluorescent X-ray spectrometer (model 3270 manufactured by Rigaku Corporation).
(4) Ratio of unsaturated dicarboxylic acid It measured with the 1H-NMR spectrometer JNM-LA400 apparatus by JEOL.
(5) Flame retardance Using a normal melt spinning apparatus, the dried polyester is a filter having a diameter of 100φ and an opening of 2000 # mounted in a nozzle pack at a spinning temperature of 300 ° C. and a discharge rate of 39.6 g / min. And was spun from a nozzle having 36 holes having a diameter of 0.25φ and L / D = 2, and the semi-undrawn yarn was wound off at a speed of 3200 m / min. The obtained semi-undrawn yarn is supplied to a drawing machine, preheated at 80 ° C., drawn 1.5 times while being in contact with a heat plate at a temperature of 150 ° C., and heat-treated to obtain a 83 dtex / 36 F filament yarn. Obtained. The obtained filament yarn was knitted and the LOI value (limit oxygen index) was measured according to JIS K 7201.

Example 1
[1] Preparation of organophosphorus compound (1) Organophosphorus compound (2) (10 kg) and itaconic acid (6.3 kg (1.02 equivalent to organophosphorus compound (2)) as aliphatic unsaturated dicarboxylic acid) And ethylene glycol (38.7 kg) were placed in a reaction vessel and reacted by heating at 130 ° C. for 3 hours under normal pressure to obtain an ethylene glycol solution of the organophosphorus compound (1).
[2] Manufacture of polyester A slurry in which the mass ratio of terephthalic acid and ethylene glycol is 1: 1.6 is continuously fed to an esterification reaction can in which a PET oligomer exists, at a temperature of 250 ° C. and a pressure of 0. An esterification reaction was performed under the conditions of 1 MPa and a residence time of 8 hours, and a PET oligomer having a reaction rate of 95% was continuously obtained.
47.3 kg of this esterified PET oligomer was transferred to a polycondensation reaction can, 12.9 kg of the solution of the organophosphorus compound (1) obtained in [1] above was added, and the temperature was set at 60 ° C. After performing depolymerization for 1 minute, 12.5 g of a solid solution (HT-P manufactured by Sakai Chemical Industry Co., Ltd.) consisting of aluminum hydroxide, magnesium hydroxide and magnesium carbonate and having an aluminum / magnesium molar ratio of 0.4 is used as a catalyst. Of 1.5 wt% ethylene glycol slurry was added. Five minutes later, the pressure reduction was started, and 60 minutes later, the pressure was reduced to 1.2 hPa or less. The temperature in the reaction vessel was raised to 275 ° C. in 30 minutes after the pressure reduction started. Under these conditions, the polycondensation reaction was carried out for 4 hours with stirring, and then discharged by a conventional method and pelletized to obtain the polyester of the present invention. This polyester had an intrinsic viscosity of 0.63, an L value of 62, a b value of 10, the copolymerization amount of the phosphorus compound was 7000 ppm as the phosphorus compound in the polyester, and the solid solution content was 250 ppm.
Next, after drying this polyester by a conventional method, it was melt-spun at a spinning temperature of 295 ° C. using an ordinary melt spinning apparatus, and the semi-undrawn yarn was scraped off at a speed of 3200 m / min. This semi-undrawn yarn is supplied to a drawing machine, preheated at 80 ° C., drawn 1.5 times while being in contact with a heat plate at a temperature of 150 ° C., and heat-treated to obtain a polyester filament of 83 dtex / 36F. I got a yarn. When this polyester filament yarn was used to measure flame retardancy (LOI value), it was good at 35.

Examples 2-4, Comparative Examples 1-4
A polyester was obtained in the same manner as in Example 1 except that the phosphorus atom content and the solid solution content composed of an aluminum compound and a magnesium compound were changed as shown in Table 1.

Comparative Example 5
A polyester was obtained in the same manner as in Example 1 except that 250 ppm of antimony trioxide was added instead of the solid solution composed of the aluminum compound and the magnesium compound.

  The results of measurement and evaluation on the properties of the polyesters obtained in the above Examples and Comparative Examples are summarized in Table 1 below.

As is clear from the results shown in Table 1, in Examples 1 to 4, the polyester of the present invention having good color tone and flame retardancy could be obtained. On the other hand, Comparative Examples 1 to 5 have the following problems.
In Comparative Example 1, since the phosphorus atom content was small, the LOI value of the obtained fiber was low, and satisfactory flame retardancy was not obtained.
In Comparative Example 2, since the content of phosphorus atoms was large, the polymerizability of the polyester was lowered, the target intrinsic viscosity could not be reached, and spinning and flame retardant evaluation could not be performed.
In Comparative Example 3, since the content of the solid solution was small, the polymerizability of the polyester was lowered, the target intrinsic viscosity could not be reached, and spinning and flame retardancy evaluation could not be performed.
In Comparative Example 4, since the solid solution content was large, the color tone of the polyester was not good and the b value was high.
In Comparative Example 5, when antimony trioxide was used instead of the solid solution, metal antimony was produced, the polyester was colored black, and the L value was low.

Claims (2)

It is a polyester having ethylene terephthalate units as a main component, and an organic phosphorus compound (1) represented by the following general formula [1] is copolymerized so that the phosphorus atom content in the polyester is 500 to 15000 ppm. A flame-retardant polyester for fibers, comprising 100 to 400 ppm of a solid solution composed of a compound and a magnesium compound, having an intrinsic viscosity of 0.6 or more and an L value in Hunter's Lab color method of 50 or more.
(In the formula, X represents an alkyl group in which two or more of the hydrogen atoms of the alkyl group are substituted with a carboxyl group.) In the method for producing a polyester mainly composed of an ethylene terephthalate unit, an organic phosphorus compound (2) obtained by reacting an organic phosphorus compound (2) represented by the following general formula [2] with an aliphatic unsaturated dicarboxylic acid ( The method for producing a flame retardant polyester for fibers according to claim 1, wherein 1) is added and a polycondensation reaction is performed using a solid solution composed of an aluminum compound and a magnesium compound as a polycondensation catalyst.