JP2008179714A - Flame-retardant copolyester composition and flame-retardant polyester fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-retardant copolyester composition excellent in melt dripping resistance (dripping resistance) and a self-extinguishing property, and to provide a flame-retardant polyester fiber. <P>SOLUTION: This flame-retardant copolyester composition is characterized by containing substantially spherical fine particles containing phosphorus atoms and having an average primary particle diameter of ≤100 nm in a copolyester copolymerized with a specific phosphaphenanthrene-based organic phosphorous compound in an amount of 0.3 to 1.5 wt.% as phosphorus atoms in an amount of 0.1 to 5 wt.% based on the copolyester. A formed product, especially a fiber, obtained from the same is especially excellent in dripping resistance and a self-extinguishing property, and is useful in fields of clothing, interiors, industrial uses, and the like. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flame retardant polyester copolymer composition and a flame retardant polyester fiber. More specifically, the present invention relates to a flame retardant polyester copolymer composition and a flame retardant polyester fiber excellent in melt dripping resistance (drip resistance) and self-extinguishing properties.

  In recent years, various organic polymer materials are required to be provided with flame retardancy, and various techniques have been developed. Polyester is widely used as a fiber, film, and resin because it has many excellent properties, but its flammability is classified as “flammable” and burns in air. For this reason, various methods for increasing the flame retardancy of polyester have been developed.

  For example, a polyester fiber mainly composed of polyethylene terephthalate will be described. As a method for improving the flame retardancy, (A) a post-processing method, (B) a blend method, and (C) a copolymerization method are known. Yes.

  The post-processing method (A) is a method of treating with a yarn or a woven or knitted fabric. A method of exhausting or adhering a halogen-based flame retardant to a fiber by a bathing method or a padding method (see Patent Document 1) From the heightened awareness of maintenance, a method of exhausting or adhering a phosphorus-based flame retardant to a fiber by a bathing method or a padding method has been proposed as a flame retardant processing technique with less environmental load (see Patent Document 2). The blending method (B) is a method in which a flame retardant is kneaded into a polymer at the polyester production stage or spinning stage, but this method has various technical difficulties and few examples have been put to practical use. As the copolymerization method of (C) above, a method in which a copolymerizable monomer (flame retardant) containing phosphorus is added to the reaction system at the polyester production stage and copolymerized randomly with the polyester has been put into practical use. As such monomers, carboxyphosphinic acid compounds (see Patent Document 3) and phosphaphenanthrene compounds (see Patent Document 4) have been proposed.

However, each of the above methods is a drip-promoting type due to the action effect that the fiber melts and drops from the fire source due to the self-extinguishing property that is characteristic of the phosphorus compound and the melt drip acceleration effect based on the melt viscosity reduction by the phosphorus compound. This method is difficult to apply to blended fiber products that impede melting, and there is a risk of burns if it adheres to the skin, and there is also a risk of secondary fire due to drip. there were.
From such a background, a flame-retardant polyester fiber having improved drip resistance during flame contact and having self-extinguishing properties has been desired.

JP 62-57985 A JP 2001-11775 A Japanese Patent Publication No.53-13479 Japanese Patent Publication No. 55-41610

  The present invention has been made in view of the above background, and its object is to provide a novel flame retardant polyester fiber that has improved drip resistance at the time of flame contact and has self-extinguishing properties. It is providing a flame-retardant polyester copolymer composition and a flame-retardant polyester fiber using the same.

  In order to achieve the above object, the present inventor has made various studies focusing on polyesters copolymerized with the above-described phosphaphenanthrene compounds, and as a result, has copolymerized a specific amount of the phosphaphenanthrene compounds. In addition, by adding a specific amount of spherical fine particles having an average primary particle size of 100 nm or less and containing phosphorus atoms to the polyester copolymer, dripping resistance is remarkably improved and excellent flame retardancy ( It was found that self-extinguishing properties can be imparted. The present invention has been completed as a result of further studies based on these findings.

  That is, the present invention relates to the following flame retardant polyester copolymer composition and flame retardant polyester fiber comprising the polyester copolymer composition.

  (1) In the copolymerized polyester in which the organic phosphorus compound represented by the following general formula (I) is copolymerized in an amount of 0.3 to 1.5% by weight as the phosphorus atom content in the polyester copolymer, A difficulty characterized by containing substantially spherical fine particles containing phosphorus atoms having an average primary particle size of 100 nm or less, in an amount of 0.1 to 5% by weight based on the polyester copolymer. A flammable polyester copolymer composition.

  (2) The above-described (1), wherein the spherical particles containing phosphorus atoms are internal precipitation fine particles obtained by causing a glycol-soluble phosphorus compound and a glycol-soluble metal compound to react with each other inside the polyester reaction system. A flame retardant polyester copolymer composition.

  (3) The flame-retardant polyester copolymer of (2) above, wherein the glycol-soluble phosphorus compound is a phosphorus compound represented by the following general formula (II) and the glycol-soluble metal compound is an alkaline earth metal compound Composition.

  (4) As a copolymerization component in the polyester copolymer, in addition to the organophosphorus compound represented by the above general formula (I), the dicarboxylic acid compound represented by the following general formula (III) comprises all of the polyester copolymer. The flame-retardant polyester copolymer composition according to any one of claims 1 to 3, which is copolymerized in an amount of 0.5 to 5.0 mol% with respect to the acid component.

  (5) The flame retardant polyester copolymer composition according to any one of the above (1) to (4), wherein the polyester copolymer is a copolymer having ethylene terephthalate as a main structural unit.

  (6) The heating residual amount when reaching 600 ° C. when heated from room temperature at a rate of 10 ° C./min in a nitrogen atmosphere is 15% by weight or more, and the temperature is raised from room temperature to 10 ° C./min in an air atmosphere. The flame-retardant polyester copolymer composition according to any one of the above (1) to (5), wherein the weight loss starting temperature when heated at a speed is 405 ° C or higher.

  (7) The flame retardant polyester copolymer composition according to any one of (1) to (6) above, having an LOI value (limit oxygen index) of 27 or more and a single fiber fineness of less than 20 dtex. Flame retardant polyester fiber characterized by.

  According to the present invention, a highly flame-retardant polyester copolymer composition that suppresses drip during combustion can be obtained, and when formed into a molded product such as a fiber, a film, a sheet, or a resin molded product, An excellent flame-retardant molded product can be obtained. In particular, the polyester fiber produced by melt spinning the polyester copolymer composition of the present invention, unlike the conventional drip-type flame-retardant polyester fiber, exhibits a drip-type flame-retardant property. Drip is suppressed. For this reason, it is possible to prevent the risk of burns and spread of fire due to flammables and melts, so that it can be suitably used for home / living textile applications such as curtains, interiors, and upholstery, clothing applications, industrial applications, etc. .

  The polyester referred to in the present invention mainly includes a terephthalate-based polyester having terephthalic acid as a main difunctional carboxylic acid component and C2-4 alkylene glycol as a main glycol component. Among them, a polyester in which 85 mol% or more of all the polyester structural units are ethylene terephthalate units is preferable.

  Such polyester is synthesized by any method. For example, polyethylene terephthalate is usually esterified directly with terephthalic acid or ethylene glycol, or transesterified with a lower alkyl ester of terephthalic acid such as dimethyl terephthalate and ethylene glycol, or with terephthalic acid and ethylene. The first stage reaction in which a glycol ester of terephthalic acid and / or its low polymer is produced by reacting with oxide and the reaction product in the first stage is heated under reduced pressure until the desired degree of polymerization is reached. It is produced by a second stage reaction that undergoes a polycondensation reaction.

  In the flame-retardant polyester copolymer of the present invention, the polyester is copolymerized with a phosphaphenanthrene-based organophosphorus compound represented by the following general formula (I) as an essential copolymerization component. is necessary.

In the above general formula (I), R ₁ is a monovalent ester-forming functional group, R ₂ and R ₃ are the same or different from each other, each having a hydrocarbon group having 1 to 10 carbon atoms and Selected from R ₁ , A represents a divalent or trivalent organic residue. n1 is 1 or 2, and n2 and n3 each represent an integer of 0 to 4.

Preferable specific examples of such organophosphorus compounds include compounds represented by the following formulas (a) to (c).

  The amount of copolymerization of the phosphaphenanthrene-based organophosphorus compound represented by the above general formula (I), which is the essential copolymerization component of the polyester in the present invention, is 0. As the phosphorus atom content in the polyester copolymer. It is necessary that the amount is in the range of 3 to 1.5% by weight, and the preferable copolymerization amount is 0.5 to 1.0% by weight, more preferably in the range of 0.6 to 0.9% by weight. is there. When the copolymerization amount of the organic phosphorus compound is less than the above range, the self-extinguishing property of the obtained polyester copolymer composition becomes insufficient. On the other hand, when the amount of copolymerization of the organophosphorus compound is too large, drip resistance is insufficient.

  In order to copolymerize the phosphaphenanthrene-based organophosphorus compound with polyester, any stage until the synthesis of the polyester described above is completed, for example, before the start of the first stage reaction, during the reaction, after the completion of the reaction, Each may be added at any stage such as during the two-stage reaction, and the polycondensation reaction may be completed after the addition.

  In addition, when synthesizing the above polyester copolymer, other dicarboxylic acid components such as isophthalic acid, hexahydroterephthalic acid, adipic acid, etc. Needless to say, a small amount of a diol component other than the number 2 to 4 may be used in combination.

  In the present invention, the flame-retardant polyester copolymer thus obtained has an average primary particle diameter of 100 nm or less and spherical fine particles containing phosphorus atoms are 0.1% to the polyester copolymer. It is contained in an amount of ˜5% by weight.

  The fine particles containing phosphorus atoms are not particularly limited as long as they are substantially spherical solid fine particles containing phosphorus atoms. For example, metal phosphate, metal phosphonate, metal phosphinate, metal pyrophosphate Examples thereof include spherical fine particles of phosphorus-containing compounds such as salts and metal phosphites. Here, “substantially spherical” refers to those having an aspect ratio of 1 to 5, as long as the shape is other than a flat shape or a linear shape. Or, an angular form such as a regular tetrahedron or a regular hexahedron is included. Moreover, as long as it is substantially spherical as a whole, a shape having a small protrusion (such as a confetti shape) or a shape having irregularities may be used.

  Specific examples of preferable phosphorus-containing compounds constituting the fine particles include phosphoric acid, phosphonic acid, phosphinic acid, pyrophosphoric acid and phosphorous acid Ca, Mg, Al, Sb, Sn, Ge, Ti, Fe, Zr, Zn , Ce, Bi, Sr, Mn, Li, Na, K salt and the like.

  Such fine particles are required to have an average primary particle diameter of 100 nm or less, preferably 50 nm or less, more preferably 1 nm to 20 nm. If the average primary particle diameter of the fine particles exceeds 100 nm, the effect of increasing the melt viscosity of the flame retardant polyester copolymer (thixotropic effect) is hardly exhibited, and the drip resistance is insufficient. The fine particles of the present invention are required to be substantially spherical.

  The fine particles may be added in an arbitrary process from the above-described polyester copolymer polymerization stage to spinning, and a production method using a polymerization addition method, a master batch method, a liquid color method, or the like is arbitrarily applied.

  In the present invention, a particularly preferred embodiment of the phosphorus-containing spherical fine particles having an average primary particle size of 100 nm or less is an internal precipitation fine particle obtained by causing a phosphorus compound soluble in glycol and a glycol-soluble metal compound to react with each other in the polyester reaction system. is there. Preferable specific examples of such internal precipitation fine particles include internal precipitation fine particles precipitated by a reaction between a metal-containing phosphorus compound represented by the following general formula (II) and an alkaline earth metal compound.

In the general formula (II), R ₄ and R ₅ are monovalent organic groups. This monovalent organic group is specifically an alkyl group, an aryl group, an aralkyl group or [(CH ₂ ) ₁ O] _k R ₆ (where R ₆ is a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, 1 Is an integer of 2 or more, and k is an integer of 1 or more. R ₄ and R ₅ may be the same or different. M is an alkali metal or alkaline earth metal, and Li, Na, K, Mg, Ca, and Sr are preferable. m is 1 when M is an alkali metal and 1/2 when M is an alkaline earth metal.

  Examples of the glycol-soluble alkaline earth metal compound include alkaline earth metal acetates, oxalates, benzoates, phthalates, stearates, organic carboxylates, ethylenediamine tetraacetate, and the like. Examples thereof include chelate compounds, halides such as chlorides, alcoholates such as methylates, ethylates and glycolates.

  Regarding the use molar ratio of the metal-containing phosphorus compound and the alkaline earth metal compound, it is preferable to use an alkaline earth metal compound in an amount of 0.5 to 1.2 times the mole of the metal-containing phosphorus compound. preferable.

  In order to form such internally precipitated fine particles in the polyester copolymer, the above-described glycol-soluble phosphorus compound and glycol-soluble metal compound can be added in any order at any stage until the synthesis of the polyester is completed. Can be done. However, if only the phosphorus compound is added at the stage where the first stage reaction has not been completed, the completion of the first stage reaction may be inhibited. If only the metal compound is added before the completion of the first stage reaction, when this reaction is an esterification reaction, coarse particles may be generated during this reaction. In this case, the amount added is preferably less than about 20% by weight of the total amount of the metal compound to be added, since it may proceed abnormally fast and cause a bumping phenomenon. Therefore, it is preferable that the addition time of at least 80% by weight to the total amount of the metal compound is after the stage at which the first stage reaction of the polyester copolymer synthesis is substantially completed. In addition, if the phosphorus compound and the metal compound are added at a stage where the second stage reaction has progressed too much, the precipitated particles tend to agglomerate and coarsen. Therefore, the addition timing is the reaction mixture in the second stage reaction. It is preferable that the intrinsic viscosity (measured with an orthochlorophenol solution at 35 ° C.) reaches 0.3. Each of the phosphorus compound and the metal compound may be added at one time, divided into two or more times, or added continuously.

  In the present invention, any catalyst can be used for the first-stage reaction, but some of the above metal compounds have catalytic ability for the first-stage reaction, particularly the transesterification reaction. When used, it is not necessary to use a separate catalyst, and this metal compound can be added before the start of the reaction of the first stage reaction or during the reaction, and can also be used as a catalyst. Since the bumping phenomenon may be caused, the amount used is preferably less than 20% by weight of the metal compound to be added.

  In the flame-retardant polyester copolymer of the present invention, in addition to the phosphaphenanthrene-based organic phosphorus compound represented by the general formula (I), a dicarboxylic acid compound represented by the following general formula (III) is further added. Copolymerization as the copolymerization component 2 is particularly preferred because the drip resistance is further improved.

In the general formula (III), B represents a naphthalene group or a biphenylene group, and R ₆ and R ₇ are a hydrogen atom, a lower alkyl group (preferably an alkyl group having 1 to 4 carbon atoms) or a phenyl group. R ₆ and R ₇ may be the same as or different from each other. R ₆ and R ₇ are particularly preferably a hydrogen atom or a methyl group.

  Specific examples of the dicarboxylic acid compound preferable as the second copolymer component include 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1 , 6-Naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid and dimethyl thereof Esters may be mentioned, and among these, 2,6-naphthalenedicarboxylic acid or dimethyl 2,6-naphthalenedicarboxylate having a molecular structure symmetry is particularly preferable. Other specific examples of preferred dicarboxylic acid compounds include diphenyl-2,2′-dicarboxylic acid, diphenyl-2,3′-dicarboxylic acid, diphenyl-2,4′-dicarboxylic acid, diphenyl-2,5′-dicarboxylic acid. Acid, diphenyl-2,6′-dicarboxylic acid, diphenyl-2,2′-dicarboxylic acid, diphenyl-2,2′-dicarboxylic acid, diphenyl-3,3′-dicarboxylic acid, diphenyl-3,4′-dicarboxylic acid Acid, diphenyl-3,5′-dicarboxylic acid, diphenyl-3,6′-dicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, diphenyl-4,5′-dicarboxylic acid, diphenyl-4,6′-dicarboxylic acid Acids and their dimethyl esters, among which diphenyl-4,4′-dicarboxylic acid or diphenyl- , 4'-dicarboxylic acid dimethyl is particularly preferred. Such dicarboxylic acid compounds may be used alone or in combination of two or more.

  The amount of copolymerization of the dicarboxylic acid compound as the second copolymer component is an amount that is in the range of 0.5 to 5.0 mol% with respect to the total acid component constituting the polyester copolymer, The range of 1.0-4.0 mol% is preferable.

  In order to copolymerize the dicarboxylic acid compound with polyester, any stage until the synthesis of the above-described polyester copolymer is completed, for example, before the start of the first stage reaction, during the reaction, after the completion of the reaction, During the reaction, it may be added at any stage such as after completion of the reaction, and the polycondensation reaction may be completed after the addition.

  In the present invention, the polyester copolymer preferably has an intrinsic viscosity (measured with an orthochlorophenol solution at 35 ° C.) of 0.50 to 0.120, and the polyester copolymer has a melting point. Is preferably from 225 to 250 ° C. from the viewpoints of moldability, physical properties of the molded product, and the like.

  The flame retardant polyester copolymer composition of the present invention may contain an optional additive such as an anti-coloring agent, a heat-resistant agent, a matting agent, a coloring agent, inorganic fine particles and the like, if necessary. .

  The flame-retardant polyester copolymer composition of the present invention is a residual residue at the time of reaching 600 ° C. when heated from room temperature at a rate of temperature increase of 10 ° C./min in a nitrogen atmosphere in an analysis using a TGA thermogravimetric apparatus. It is preferable to obtain a drip-resistant flame resistance when the amount is 15% by weight or more and the weight loss starting temperature is 405 ° C. or more when heated from room temperature to 10 ° C./min in an air atmosphere. That is.

  In order to mold the flame retardant polyester copolymer composition thus obtained, it is not necessary to adopt a special method, and a normal polyester melt molding method is arbitrarily employed. For example, in the case of forming a fiber, it can be spun by a known melt spinning method, and the spun fiber may be a solid fiber having no hollow part or a hollow fiber having a hollow part. In addition, the outer shape and the shape of the hollow part in the cross section of the fiber to be spun may be circular or irregular. As a spinning method, a method of spinning at a speed of 500 to 2500 m / min, drawing and heat treatment, a method of spinning at a speed of 1500 to 5000 m / min, and performing drawing and false twisting simultaneously or sequentially, 5000 m / min. Spinning conditions such as a method of spinning at the above high speed and omitting the drawing step may be arbitrarily adopted depending on the application. In this case, since the shape of the fine particles is spherical in the present invention, the process passability and yarn physical properties of the fine fineness yarn having a single fiber fineness of less than 20 dtex are particularly superior to those of plate-like or needle-like fine particles. Therefore, the single fiber fineness is preferably less than 20 dtex.

  Thus, the preferable flame-retardant polyester fiber manufactured by the melt spinning method from the flame-retardant polyester copolymer composition has a LOI value (limit oxygen index) determined by the method described later of 27 or more.

  The flame-retardant polyester copolymer of the present invention can be formed into a molded product such as a film or a sheet in addition to the fiber, and any molding conditions can be employed. For example, any conditions such as a method of applying anisotropy by applying tension in only one direction after film formation, a method of stretching in two directions simultaneously or in an arbitrary order, a method of stretching in two or more stages, etc. are adopted. .

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. However, the present invention is not limited by these. In addition, unless otherwise indicated, the part and% in these Examples and Comparative Examples show a weight part and weight%, respectively. Each measured value in the present invention is measured by the following method.

(1) Intrinsic viscosity of polyester copolymer:
The intrinsic viscosity of the polyester copolymer was determined from the value measured with an orthochlorophenol solution at 35 ° C.

(2) Average primary particle size of precipitated fine particles:
The chips before spinning and the fibers after spinning are larger than the fine particle diameter of the single particles of primary particles existing in the chips or fibers, and within a thickness of several times the particle diameter, that is, several tens nm to around 100 nm. Slice to thickness with an ultramicrotome. The sliced ultrathin section is magnified several thousand times to 100,000 times with a transmission electron microscope to obtain a photograph in which primary particles and secondary particles formed therefrom can be identified. The average value of the particle diameter is obtained.

(3) Content of precipitated fine particles:
Chips before spinning and fibers after spinning are dissolved in orthochlorophenol (145 ° C. × 4 hours), and the precipitated fine particles are separated by ultracentrifugation (30000 rpm, 40 minutes × 4 times). Obtained by precise weighing.

(4) Melting point of polyester copolymer Test using a differential scanning calorimeter (DSC2200 Differential Scanning Calorimeter manufactured by TA Instruments) to cool a sample heated to 280 ° C at a temperature rising rate of 20 ° C / min. A sample rapidly cooled in a tube and brought into an amorphous state was further heated at a rate of temperature increase of 20 ° C./min, and the melting peak temperature was measured according to JIS K7121 to obtain a melting point.

(5) Residual heating amount when reaching 600 ° C .:
In the analysis using the TGA thermogravimetry device (Thermogravimetry device TGA851e manufactured by METTLER TOLEDO), the heating residue at the time of reaching 600 ° C when the sample was heated from room temperature to 10 ° C / min in a nitrogen atmosphere The amount was displayed as a value relative to the sample weight at the start of measurement at room temperature.

(6) Weight loss start temperature:
Measure the thermogravimetric curve of the sample when the dried polymer sample is heated from room temperature to 10 ° C / min in an air atmosphere using a TGA thermogravimetry device (Metra Toledo's thermogravimetry device TGA851e). The weight loss starting temperature was determined according to JIS K-7120.

(7) Combustion test of polymer test piece:
Hold a 5 mm wide, 2 mm thick, 5 cm long polymer test piece vertically, adjust the flame of the ignition device (Gasmatch Pro II made by Iwatani Corporation) to a length of 30 mm, and place it in the center of the lower end of the test piece. Indirect flame was applied for 10 seconds, and the test piece was ignited. When the flame was extinguished, an indirect flame was further observed for 10 seconds, and the combustion state of the test piece observed for combustion was determined based on the evaluation criteria for drip resistance and flame resistance shown in Table 1 below. The higher the score, the better the drip resistance and flame retardancy.

(8) Yarn strength:
A tensile test using Tensilon RTC-1210A type manufactured by Orientec Co., Ltd. was carried out, and the tensile elongation curve was obtained (yarn length 20 cm, tensile speed 20 cm / min).

(9) LOI value (limit oxygen index) of fiber fabric:
It measured according to JIS L 1091 E-3 (glass fiber sewing machine sewing).

[Example 1]
100 parts of dimethyl terephthalate, 60 parts of ethylene glycol, and 0.06 part of calcium acetate monohydrate (0.066 mol% with respect to dimethyl terephthalate) were charged into a transesterification can and 140 ° C. over 4 hours in a nitrogen gas atmosphere. The ester exchange reaction was carried out while distilling out the methanol produced by raising the temperature to 230 ° C. from the system. Subsequently, 0.5 parts of trimethyl phosphate (0.693 mol% with respect to dimethyl terephthalate) and 0.31 part of calcium acetate monohydrate (1 with respect to trimethyl phosphate) were added to the reaction product obtained. / 2 moles) in 8.5 parts of ethylene glycol at 120 ° C. for 60 minutes under total reflux for 9.31 parts of a transparent solution of calcium phosphate diester calcium salt prepared at room temperature for 0.57 minutes. 9.88 parts of a mixed clear solution of calcium phosphate diester calcium salt and calcium acetate obtained by dissolving 1 mg of calcium acetate monohydrate (0.9 moles relative to trimethyl phosphate) was added. Subsequently, 0.04 part of antimony trioxide was added, and at the same time, the temperature was raised to 240 ° C. while removing excess ethylene glycol, and then transferred to a polymerization can.

  15.4 parts of a 63% ethylene glycol solution of the organophosphorus compound represented by the above formula (a) in a polymerization can (0.69% as a phosphorus atom relative to dimethyl terephthalate, and 0.2% as a phosphorus atom in the polyester copolymer). 64%), the pressure was reduced from 760 Torr to 1 Torr over 1 hour, and the temperature was raised from 240 ° C. to 280 ° C. over 1 hour 30 minutes. Polymerization was further performed for 2 hours at a polymerization temperature of 280 ° C. under a reduced pressure of 1 Torr or less. The obtained polymer was chipped according to a conventional method. This chip was subjected to DSC melting point measurement, TGA thermogravimetry and combustion test. The results are shown in Table 2.

Further, this chip was dried according to a conventional method, and then melt-spun at 285 ° C. using a spinneret having 24 circular spinning holes having a hole diameter of 0.3 mm. Next, the obtained undrawn yarn was drawn and heat-treated using a heating roller at 84 ° C. and a plate heater at 180 ° C. at a draw ratio such that the elongation of the drawn yarn finally obtained was 30%. A drawn yarn having a strength of 4.5 cN / dtex with a / 24 filament was obtained. In this multifilament, from the transmission electron micrograph of the cross section of the fiber, the internally precipitated fine particles of the phosphorus-containing compound are present in a spherical shape with an aspect ratio of approximately 1, and the average primary particle diameter is 5.3 nm. And its content was 0.51%.
Using the obtained drawn yarn, a tubular knitted fabric was knitted according to a conventional method, subjected to scouring and presetting, and then the LOI value was measured. The results were as shown in Table 2.

[Example 2]
100 parts of dimethyl terephthalate, 3.77 parts of dimethyl 2,6-naphthalenedicarboxylate (3.0 mol% relative to dimethyl terephthalate), 60 parts of ethylene glycol, 0.06 part of calcium acetate monohydrate (dimethyl terephthalate) 0.066 mol%) was charged in a transesterification can and the temperature was raised from 140 ° C to 230 ° C over a period of 4 hours in a nitrogen gas atmosphere. It was. Subsequently, 0.5 parts of trimethyl phosphate (0.693 mol% with respect to dimethyl terephthalate) and 0.31 part of calcium acetate monohydrate (1 with respect to trimethyl phosphate) were added to the reaction product obtained. / 2 moles) in 8.5 parts of ethylene glycol at 120 ° C. for 60 minutes under total reflux for 9.31 parts of a transparent solution of calcium phosphate diester calcium salt prepared at room temperature for 0.57 minutes. 9.88 parts of a mixed clear solution of calcium phosphate diester calcium salt and calcium acetate obtained by dissolving 1 mg of calcium acetate monohydrate (0.9 moles relative to trimethyl phosphate) was added. Next, 0.04 part of antimony trioxide was added, and the temperature was raised to 240 ° C. while expelling excess ethylene glycol.

  15.4 parts of a 63% ethylene glycol solution of the organophosphorus compound represented by the above formula (a) in a polymerization can (0.69% as a phosphorus atom relative to dimethyl terephthalate, and 0.2% as a phosphorus atom in the polyester copolymer). 62%), the pressure was reduced from 760 Torr to 1 Torr over 1 hour, and the temperature was increased from 240 ° C. to 280 ° C. over 1 hour 30 minutes. Polymerization was further performed for 2 hours at a polymerization temperature of 280 ° C. under a reduced pressure of 1 Torr or less. The obtained polymer was chipped according to a conventional method. This chip was subjected to DSC melting point measurement, TGA thermogravimetry and combustion test. The results were as shown in Table 2.

Further, this chip was dried according to a conventional method, and then melt-spun at 285 ° C. using a spinneret having 24 circular spinning holes having a hole diameter of 0.3 mm. Next, the obtained undrawn yarn is subjected to a drawing heat treatment using a heating roller at 84 ° C. and a plate heater at 180 ° C. at a draw ratio such that the elongation of the drawn yarn finally obtained is 30%. A drawn yarn having a fineness of 84 dtex / 24 filament and a strength of 4.5 cN / dtex was obtained. In this multifilament, from the transmission electron micrograph of the cross section of the fiber, the internally precipitated fine particles of the phosphorus-containing compound are present in a spherical shape with an aspect ratio of approximately 1, and the average primary particle diameter is 6.5 nm. And its content was 0.49%.
Using the obtained drawn yarn, a tubular knitted fabric was knitted according to a conventional method, subjected to scouring and presetting, and then the LOI value was measured. The results were as shown in Table 2.

[Comparative Example 1]
Instead of the mixed transparent solution of calcium phosphate diester calcium salt and calcium acetate used in Example 1, 4 parts of 15% ethylene glycol dispersion of calcium phosphate having an average primary particle size of 0.3 μm (as calcium phosphate particles relative to dimethyl terephthalate) 0.6 part) was added in the same manner as in Example 1. In the obtained multifilament, from the transmission electron micrograph of the fiber cross section, the calcium phosphate particles are present in a spherical shape with an aspect ratio of approximately 1, and the average primary particle diameter is 0.33 μm. The content was 0.55%. The results were as shown in Table 2.

  According to the present invention, a highly flame-retardant polyester copolymer composition that suppresses drip during combustion can be obtained, and when formed into a molded article such as a fiber, a film, or a resin, the flame retardant has excellent flame resistance. Can be obtained. In particular, the polyester fiber produced by melt spinning the polyester copolymer composition of the present invention exhibits a drip-resistant flame resistance unlike the conventional drip-type flame-retardant polyester fiber. Is suppressed. For this reason, the fibers and other molded articles made of the copolymerized polyester composition of the present invention can be suitably used for home / living textile applications such as curtains, interiors, and chair upholstery, clothing applications, and industrial applications.

Claims (7)

The average primary particles in the copolymerized polyester in which the organic phosphorus compound represented by the following general formula (I) is copolymerized in an amount of 0.3 to 1.5% by weight as the content of phosphorus atoms in the polyester copolymer A flame retardant polyester having a diameter of 100 nm or less and containing substantially spherical fine particles containing phosphorus atoms in an amount of 0.1 to 5% by weight based on the polyester copolymer Copolymer composition.

  The spherical particles containing a phosphorus atom are internally precipitated fine particles obtained by causing a glycol-soluble phosphorus compound and a glycol-soluble metal compound to react with each other inside a polyester reaction system and depositing them. Flame retardant polyester copolymer composition. The flame-retardant polyester copolymer composition according to claim 2, wherein the glycol-soluble phosphorus compound is a phosphorus compound represented by the following general formula (II), and the glycol-soluble metal compound is an alkaline earth metal compound. object.

In the polyester copolymer, in addition to the organophosphorus compound represented by the above general formula (I) as a copolymer component, the dicarboxylic acid compound represented by the following general formula (III) is added to all the acid components constituting the polyester copolymer. The flame-retardant polyester copolymer composition according to any one of claims 1 to 3, which is copolymerized in an amount of 0.5 to 5.0 mol%.

  The flame-retardant polyester copolymer composition according to any one of claims 1 to 4, wherein the polyester copolymer is a copolymer having ethylene terephthalate as a main constituent unit.   When heated at a rate of temperature increase of 10 ° C./min from room temperature in a nitrogen atmosphere, the amount of heating residue when reaching 600 ° C. is 15% by weight or more and heated at a rate of temperature increase of 10 ° C./min from room temperature in an air atmosphere The flame retardant polyester copolymer composition according to any one of claims 1 to 5, wherein the weight loss starting temperature is 405 ° C or higher.   It consists of the flame-retardant polyester copolymer composition of any one of Claims 1-6, and LOI value (limit oxygen index) is 27 or more, and a single fiber fineness is less than 20 dtex. Flame retardant polyester fiber characterized by.