JP2003128772A - Flame-retardant polyester and fiber comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flame-resistant polyester which has an excellent color tone, hardly develops deposits on a spinneret even when the polyester is continu ously melt-spun through the spinneret for a long period, and has excellent moldability, namely excellent performance, and to provide a fiber using the flame-resistant polyester. SOLUTION: This flame-resistant polyester in which at least 80 mol.% of repeating units constituting the polyester are ethylene terephthalate units and which is copolymerized with a phosphorus compound (A) represented by a specific structural formula in an amount of 0.3 to 1.5 wt.% as phosphorus element on the basis of the polyester component is characterized by containing a titanium compound soluble in the polymer in a titanium metal element amount of 2 to 10 mmol.% based on the total dicarboxylic acid component and satisfying the following expressions (1) and/or (2): 2<=P/Ti<=15 (1), 10<=Ti+P<=100 (mmol.%) (2) [Ti is the concentration (mmol.%) of the titanium metal element of the polyester-soluble titanium compound contained in the polyester; P is the concentration (mmol.%) of the phosphorus element except the phosphorus compound (A) contained in the polyester].

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a flame-retardant polyester and a fiber comprising the same. More specifically, using a catalyst for producing a polyester containing a specific titanium compound and phosphorus compound, the color tone is excellent, and the amount of spinneret deposits is extremely small even when continuously spun through the spinneret for a long time. And a fiber comprising the same, which is excellent in flame retardancy and has excellent flame retardancy.

[0002]

2. Description of the Related Art Polyesters, particularly polyethylene terephthalate, polyethylene naphthalate, polytrimethylene terephthalate and polytetramethylene terephthalate, are excellent in mechanical, physical and chemical properties and are suitable for forming fibers, films and other molded products. Widely used. However, polyester is flammable like many other chemical fibers, but in recent years, there has been an increasing demand for flame retardancy from the viewpoint of respect for human life and fire prevention. It cannot be said that flame retardancy is sufficient for using such polyester as a fiber for clothing or a fiber for non-clothing mainly in interiors such as curtains and interior covers. In order to make up for such drawbacks, post-processing methods of adding phosphorus and a halogen-based flame retardant after molding and blending methods of adding a flame retardant during molding have been known as flame retardant technologies. However, since all of these are merely added with agents, there is a problem in terms of durability. Therefore, a method of copolymerizing a flame retardant in a polymerization step is known (JP-A-5-106168, JP-A-6-13).
(See Japanese Patent No. 6666).

By the way, in such a flame-retardant polyester, usually terephthalic acid and ethylene glycol are directly esterified or a lower alkyl ester of terephthalic acid such as dimethyl terephthalate is transesterified with ethylene glycol. Alternatively, terephthalic acid is reacted with ethylene oxide to form an ethylene glycol ester of terephthalic acid and / or a low polymer thereof, and then the reaction product is heated under reduced pressure in the presence of a polycondensation catalyst to perform a predetermined polymerization. Manufactured by polycondensation reaction to a certain degree.

It is well known that the type of catalyst used in these polycondensation reaction steps greatly influences the reaction rate and the quality of the obtained polyester. The modified polyester can carry out the polycondensation reaction by using the same polycondensation catalyst as the known polyester. For example, the antimony compound is most widely used because it has excellent polycondensation catalyst performance. .

However, in the case of a polyester using an antimony compound as a polycondensation catalyst, when the polyester is continuously melt-spun for a long period of time, the reduced antimony metal becomes foreign matter and the pressure (pack pressure) in the spinning filtration section is increased. There is a problem that a rise occurs. In addition, foreign matter (hereinafter sometimes simply referred to as the foreign matter of the spinneret) is deposited around the spinneret hole, and a bending phenomenon (bending) of the molten polyester flow occurs, which causes fluff and / or fluff in the spinning and drawing processes. Alternatively, there is a problem of moldability that a yarn breakage occurs. As a result, they have been a cause of markedly reducing productivity.

It has been proposed to use a titanium compound such as titanium tetrabutoxide as a polycondensation catalyst other than the antimony compound. However, when such a titanium compound is used, the problem of moldability due to the accumulation of foreign matter on the die as described above can be solved, but the obtained polyester itself is colored yellow, and the melt thermal stability is also high. There is a new problem of being defective.

In order to solve the above coloring problem, it is generally practiced to add a cobalt compound to polyester to suppress yellowing. It is true that the yellowing (b value) of polyester can be improved by adding a cobalt compound, but the addition of the cobalt compound lowers the melt thermal stability of the polyester and makes it easier for the polyester to decompose. There's a problem.

Further, as another titanium compound, Japanese Patent Publication No.
No. 8-2229 discloses titanium hydroxide and Japanese Patent Publication No.
JP-A 7-26597 discloses the use of α-titanic acid as a catalyst for polyester production. However, in the former method, it is not easy to pulverize titanium hydroxide into powder, while in the latter method, α-titanic acid is likely to be deteriorated, so that its storage and handling are not easy.
Therefore, neither is suitable for industrial use, and it is also difficult to obtain a polyester having a good yellowness (b value).

Further, JP-B-59-46258 discloses a product obtained by reacting a titanium compound with trimellitic acid, and JP-A-58-38722 discloses a titanium compound and a phosphite. It is disclosed that each of the products obtained by reacting with and is used as a catalyst for producing polyester. Certainly, according to these methods, the melt heat stability of the polyester is improved to some extent, but the color tone of the obtained polyester is not sufficient. Therefore, further improvement of the color tone of polyester is desired.

As described above, it is effective not to use an antimony compound as a catalyst for suppressing foreign substances from the die, but in a method not using an antimony compound,
Conventionally, it cannot be used because the color tone of the thread deteriorates.

Therefore, there has been a demand for a modified polyester fiber which is less likely to cause foreign matter in the die and has an excellent color tone.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide an excellent color tone, and even when continuously spun for a long time, the increase in pack pressure and the amount of foreign matter in the die are very small, the moldability is excellent, and the high productivity is achieved. To provide a flame-retardant polyester and a fiber having improved color tone with excellent properties.

[0013]

The present inventors have completed the present invention as a result of intensive investigations in view of the above-mentioned prior art. That is, 1. At least 80 of the constituents of polyester
Mol% is ethylene terephthalate and has the following general formula (I)

[0014]

[Chemical 5]

(In the above formula, R is a saturated group having 10 or less carbon atoms,
And a linear, branched, or cyclic alkylene group, an arylene group having 6 to 10 carbon atoms, or an arylalkylene group having 7 to 10 carbon atoms, R ₁ is an alkyl group having 6 or less carbon atoms, and 6 to 6 carbon atoms. 10 aryl groups or 7 to 7 carbon atoms
10 represents the arylalkyl group. R ₂ and R ₃ represent an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a hydrogen atom. In a polyester obtained by copolymerizing the bifunctional phosphorus compound (A) represented by the formula (3) with 0.3 to 1.5% by weight as a phosphorus element based on the polyester component, a titanium compound soluble in the polyester and A phosphorus compound (B) having a maximum number of hydroxyl groups, ester groups or carboxyl groups of 1 or less is contained, and the content of the titanium compound soluble in polyester is 2 as a titanium metal element for all dicarboxylic acid residue components. 10 to 10 mmol%, the following formula (1) and / or (2) formula 2 ≦ P / Ti ≦ 15 (1) 10 ≦ Ti + P ≦ 100 (mmol%) (2) (where Ti is in the polyester Concentration of titanium metal element of the polyester-soluble titanium compound contained in (Pt), P is the concentration of phosphorus element (B) contained in the polyester in terms of phosphorus element (m The flame-retardant polyester and the fiber made of the flame-retardant polyester satisfying the condition (1).

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

In the polyester of the present invention, at least 80 mol% or more of repeating units must be ethylene terephthalate. When the ethylene terephthalate unit content is less than 80 mol%, basic physical properties such as strength and elongation of the obtained polyester fiber cannot be sufficiently maintained, which is not preferable.

The phosphorus compound (A) used as a flame retardant in the present invention acts as a flame retardant and has the following formula (I):

[0019]

[Chemical 6]

(In the above formula, R is a saturated group having 10 or less carbon atoms,
And a linear, branched, or cyclic alkylene group, an arylene group having 6 to 10 carbon atoms, or an arylalkylene group having 7 to 10 carbon atoms, R ₁ is an alkyl group having 6 or less carbon atoms, and 6 to 6 carbon atoms. 10 aryl groups or 7 to 7 carbon atoms
10 represents the arylalkyl group. R ₂ and R ₃ represent an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a hydrogen atom. ).

In the above formula, R is a saturated, straight-chain, branched or cyclic alkylene group having 10 or less carbon atoms, an arylene group having 6 to 10 carbon atoms, or an arylalkylene group having 7 to 10 carbon atoms. Represent When R is a functional group having a large number of carbon atoms other than these, the thermal stability of the R group portion becomes poor, which is not preferable. Preferable examples of R include ethylene group, propylene group, phenylene group and the like. R ₁ is an alkyl group having 6 or less carbon atoms, 6 to 6 carbon atoms
It represents an aryl group having 10 or an arylalkyl group having 7 to 10 carbon atoms. It is not preferable that R ₁ is a functional group having a large number of carbon atoms other than these, because the R ₁ portion is likely to be thermally decomposed. In addition, R and / or R ₁ may contain one or more heteroatoms. In particular, it may contain F, Cl, O or S.

R ₂ and R ₃ represent an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a hydrogen atom. If the carbon number exceeds 18, it becomes difficult to copolymerize the phosphorus compound (A) with the polyester molecular chain by the transesterification reaction, and the durability becomes inferior like the addition-type flame retardant, which is not preferable.

The phosphorus compound (A) in the present invention needs to be bifunctional. The reason for this is to copolymerize in the polyester molecular chain. The absence of a functional group capable of reacting with polyester is not preferable because the flame retardant is released during the molding process such as spinning and the flame retardant effect is not sufficiently exhibited. In the case of monofunctionality, it reacts with the terminal of the polyester molecular chain, acts as a polymerization terminator in the polyester polymerization reaction step, and the molecular weight of the polyester is not sufficiently increased, which is not preferable. As the functional group capable of reacting with the polyester, an alcoholic hydroxyl group, a phenolic hydroxyl group, or an ester group of them and a carboxyl group, (sub) phosphoric acid group, (sub)
Examples thereof include a sulfate group, or an ester group of them and an organic group.

Preferred examples of the phosphorus compound (A) include:
3-Methyl-phosphico-propionic acid, 3-ethyl-
Phosphyco-propionic acid, 3-methyl-phosphico-
Examples include propionic acid.

The phosphorus compound (A) in the present invention must be copolymerized in the range of 0.3 to 1.5% by weight as a phosphorus element based on the polyester. When the copolymerization amount is less than 0.3% by weight as elemental phosphorus, the flame retarding effect becomes poor, which is not preferable. When the copolymerization amount exceeds 1.5% by weight as elemental phosphorus, the heat resistance of the entire polyester fiber obtained becomes poor, and the physical properties of the polyester fiber deteriorate, resulting in spin filtration due to thermally decomposed organic foreign matter. It is not preferable because the pressure (pack pressure) in the part will remarkably increase.

The polyester used in the present invention is the third one in addition to the ethylene terephthalate component constituting the polyester.
The components may be copolymerized, and the third component may be either a dicarboxylic acid component or a glycol component. Third
Examples of the dicarboxylic acid component preferably used as the component include aromatic dicarboxylic acids such as isophthalic acid, 5-sodium sulfoisophthalic acid, 2,6-naphthalenedicarboxylic acid and phthalic acid; adipic acid, azelaic acid, sebacic acid, decanedicarboxylic acid. Examples thereof include aliphatic dicarboxylic acids such as acids and the like; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and the like, and examples of the glycol component include diols such as diethylene glycol, trimethylene glycol, tetramethylene glycol and cyclohexanedimethanol. These may be used alone or in combination of two or more.

In the present invention, it is necessary to use a titanium compound soluble in polyester from the viewpoint of reducing foreign matters caused by the catalyst, as the titanium compound used. The titanium compound is not particularly limited with respect to other requirements, and a titanium compound generally used as a polycondensation catalyst for polyester, for example,
Titanium acetate, tetra-n-butoxytitanium and the like can be mentioned, but particularly preferable is the following formula (III).

[0028]

[Chemical 7]

(In the above formula, R _{6 to} R ₉ are the same or different alkyl groups having 2 to 10 carbon atoms, or 6 carbon atoms.
~ 15 represents an aryl group, m represents an integer of 1-3. ) Or a compound represented by the above formula (III) and the following formula (IV)

[0030]

[Chemical 8]

(In the above formula, n represents an integer of 2 to 4), which is a product obtained by reacting an aromatic polycarboxylic acid or an acid anhydride thereof.

The titanium compound represented by the above formula (III) is not particularly limited as long as R _{6 to} R ₉ are the same or different alkyl groups having 2 to 10 carbon atoms or aryl groups having 6 to 15 carbon atoms. , Tetraisopropoxy titanium, tetra-n-propoxy titanium, tetra-n-
Butoxy titanium, tetraethoxy titanium, and tetraphenoxy titanium are preferably used. Further, as the aromatic polyvalent carboxylic acid represented by the general formula (IV) or its acid anhydride to be reacted with the titanium compound, phthalic acid, trimellitic acid, hemimellitic acid, pyromellitic acid or their acid anhydrides can be used. The thing is used preferably. The aromatic polycarboxylic acid or its acid anhydride may be used alone or in combination of two or more kinds. When the titanium compound is reacted with an aromatic polyvalent carboxylic acid or an acid anhydride thereof, the aromatic polyvalent carboxylic acid or an acid anhydride thereof is dissolved in a solvent, and the titanium compound is added dropwise to the solution. ~ 2
The reaction may be performed at a temperature of 00 ° C for 30 minutes or more.

The polyester of the present invention must contain a titanium compound soluble in the polyester as a titanium metal element in an amount of 2 to 10 mmol% based on all dicarboxylic acid components. When the titanium metal element is less than 2 mmol%, the productivity of the polyester is lowered and a polyester having a target molecular weight cannot be obtained. On the other hand, when the content of the titanium metal element exceeds 10 mmol%, the thermal stability is decreased to the contrary, and the decrease in the molecular weight at the time of fiber production becomes large, and a polyester fiber of excellent quality cannot be obtained. The amount of titanium metal element is preferably in the range of 2.5 to 8 mmol%, more preferably in the range of 3 to 7 mmol%. Incidentally, the term "titanium compound soluble in polyester" as used herein means that when a titanium compound is used as a catalyst for the polycondensation reaction, the amount thereof is used, and when the titanium catalyst is also used for the first step reaction by the transesterification reaction. Indicates the total amount of the titanium compound used as the transesterification reaction catalyst and the titanium compound used as the polycondensation reaction catalyst. In the present invention, it is also preferable that a part or the whole amount of the titanium compound is added before the start of the transesterification reaction, and the transesterification reaction catalyst and the polycondensation reaction catalyst to be carried out thereafter are used in combination as two kinds of catalysts. It is mentioned as one aspect.

The polyester in the present invention is produced by using a titanium compound as a catalyst and a phosphorus compound (B) having a maximum number of hydroxyl groups, ester groups or carboxyl groups of 1 or less as a stabilizer.

The phosphorus compound (B) in the present invention has a maximum number of hydroxyl groups, ester groups or carboxyl groups of 1 or less. In the case of having two or more groups, copolymerization with the polyester molecule results in a substantial decrease in the molar balance with respect to the titanium compound, which is not preferable because the effect is poor. Examples of the phosphorus compound (B) in the present invention include phosphoric acid, phosphorous acid, phosphonic acid, trimethyl phosphate, phosphonate compounds and their derivatives. These may be used alone or in combination of two or more. According to the studies by the present inventors, the phosphorus compound (B) is represented by the following formula (II)

[0036]

[Chemical 9]

(In the above formula, R ₄ and R ₅ may be the same or different and represent an alkyl group having 1 to 4 carbon atoms, and X represents —CH ₂ — or —CH (Y). (Y represents an aromatic ring), it is possible to obtain a particularly excellent yellowing-preventing effect and die foreign-body preventing effect when a phosphonate compound represented by the formula (1) is used. Particularly specifically, carbomethoxymethanephosphonic acid, carboethoxymethanephosphonic acid, carbopropoxymethanephosphonic acid, carboptoxymethanephosphonic acid, carbomethoxy-phosphono-phenylacetic acid, carboethoxy-phosphono-phenylacetic acid, carboprotoxy- Examples thereof include phosphono-phenylacetic acid and carbobutoxy-phosphono-phenylacetic acid.

The reason why the above phosphonate compound is preferable is that the catalyst activity in the titanium compound is maintained during the polycondensation reaction because the reaction with the titanium compound progresses relatively slowly compared to the phosphorus compound which is usually used as a stabilizer. Since the time is long and the amount added to the polyester can be reduced as a result, and even when a large amount of stabilizer is added to the catalyst as in the present invention, it has the property of not impairing the thermal stability of the polyester. is there.

The timing of adding the phosphorus compound (B) is
It may be any time before the transesterification reaction is completed or after the esterification reaction is substantially completed, for example,
At atmospheric pressure before starting the polycondensation reaction, under reduced pressure after starting the polycondensation reaction, at the end of the polycondensation reaction, or after the polycondensation reaction is completed, that is, after the polyester is obtained Good.

In the present invention, the following formulas (1) and /
Or (2) 2 ≦ P / Ti ≦ 15 (1) 10 ≦ Ti + P ≦ 100 (mmol%) (2) (In the above formula, Ti is the concentration of the titanium metal element of the polyester-soluble titanium compound contained in the polyester. (Mmol%) and P indicate the concentration (mmol%) of the phosphorus element in the phosphorus compound (B) contained in the polyester).

When (P / Ti) is less than 2, the color tone is remarkably yellowed, which is not preferable. Also, (P / Ti) is 15
When it exceeds, the polymerization reactivity of the polyester is significantly reduced,
The target polyester cannot be obtained. In the polyester used in the present invention, the proper range of (P / Ti) is characteristically narrower than that of a normal metal catalyst, but when it is in the proper range, it is possible to obtain an unprecedented effect like the present invention. . On the other hand, if the content of (Ti + P) is less than 10 mmol%, the productivity in the yarn making process is significantly reduced, and satisfactory performance cannot be obtained. In addition, (Ti +
If P) exceeds 100 mmol%, a small amount of foreign matter due to the catalyst is generated, which is not preferable.

The ranges of formulas (1) and (2) are preferably (P / Ti) in the range of 3 to 12 in the formula (1), and (Ti + P) in the formula (2) is 15 to 85 mmol%. And more preferably (P / Ti) in the formula (1) is from 4 to
The range of 10 and (Ti + P) in the formula (2) are in the range of 20 to 70 mmol%.

Generally, as a raw material for a polyester having ethylene terephthalate as a main repeating unit, a production method using an aromatic dicarboxylic acid represented by terephthalic acid, and an ester-forming derivative of an aromatic dicarboxylic acid represented by dimethyl terephthalate. There are two known methods using as a raw material. The polyester in the present invention is not particularly limited depending on its production method, but a production method via an ester exchange reaction in which dimethyl terephthalate as a raw material of the ethylene terephthalate component is 80 mol% or more of all dicarboxylic acid components is preferable. . The production method using dimethyl terephthalate as a raw material has an advantage that the phosphorus compound (B) added as a stabilizer during the polycondensation reaction is less scattered than the production method using terephthalic acid as a raw material.

Further, in the production method using dimethyl terephthalate as the raw material, the addition amount of the titanium compound can be reduced, and a part and / or the total amount of the titanium compound is added before the start of the transesterification reaction, and the transesterification catalyst and the heavy catalyst are added. A production method in which the two catalysts of the condensation reaction catalyst are also used is preferable, and the transesterification reaction is further performed at 0.05 to 0.20 MP.
The method of carrying out under a pressure is more preferable.

The pressure applied during the transesterification reaction is 0.05M.
If it is less than Pa, the promotion of the reaction due to the catalytic action of the titanium compound is not sufficient. On the other hand, if it exceeds 0.20 MPa, the content of diethylene glycol, which is a by-product, in the polymer is remarkably increased, and the heat stability of the polyester is improved. The characteristics such as sex are inferior.

The intrinsic viscosity (o-chlorophenol solvent, 35 ° C.) of the polyester in the present invention is 0.40 to
It is preferably in the range of 0.80, particularly 0.45
A range of 0.75 is preferred. When the intrinsic viscosity is less than 0.40, the strength of the fiber becomes insufficient, which is not preferable. On the other hand, if the intrinsic viscosity exceeds 0.80, melt spinning from polyester becomes difficult, which is not preferable.

The polyester in the present invention may contain a small amount of additives such as lubricants, pigments, dyes, antioxidants, solid-state polymerization accelerators, optical brighteners, antistatic agents, antibacterial agents, and ultraviolet absorbers, if necessary. , A light stabilizer, a heat stabilizer, a light-shielding agent, a matting agent and the like may be contained, and titanium oxide and the like are preferably added as a matting agent.

The production method for producing the polyester fiber of the present invention is not particularly limited, and a conventionally known melt spinning method can be arbitrarily adopted. For example, 270 ° C
Melt spinning is preferably performed in the range of to 300 ° C., and the spinning speed is preferably 400 to 5000 m / min. When the spinning speed is in this range, the strength of the obtained fiber is sufficient and the fiber can be wound stably. In addition, the stretched yarn can be obtained by winding the polyester fiber or by continuously stretching the fiber without once winding it. Further, the polyester fiber of the present invention is also preferably subjected to alkali reduction treatment in order to enhance the feeling.

In producing the polyester fiber of the present invention, there is no limitation on the shape of the spinneret used during spinning, and any shape such as circular, irregular, solid or hollow can be adopted.

The polyester fiber in the present invention can be dyed with a conventionally used dye, and a flame-retardant polyester fiber having a clear and excellent color tone can be obtained.

[0051]

The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to these examples. The intrinsic viscosity, color tone, titanium content, and layer of deposits generated on the spinneret were measured by the methods described below.

(1) Intrinsic viscosity: The intrinsic viscosity of the polyester polymer is 35 for an o-chlorophenol solution.
It was determined from the viscosity value measured at ° C.

(2) Color tone (L value and b value): A polymer sample was melted at 290 ° C. under vacuum for 10 minutes, and immediately after molding this into an aluminum plate into a plate having a thickness of 3.0 ± 1.0 mm. Quench in ice water and heat the plate to 160 ° C, 1
After time-drying crystallization treatment, place on a white standard plate for color difference meter adjustment, and measure the Hunter L value and b value of the plate surface,
It was measured using a Hunter type color difference meter CR-200 manufactured by Minolta. The L value indicates the lightness, the larger the value, the higher the lightness, and the larger the value, the higher the degree of yellow coloring.

(3) Titanium content of catalyst: The titanium concentration in the catalyst compound is determined by the fluorescent X-ray measuring device 3270 manufactured by Rigaku Corporation.
Was measured using.

(4) Evaluation of increase in spinning filtration pressure: A spinning machine equipped with a wire net having a diameter of 2400 mesh and a diameter of 25 mm directly above the spinneret was loaded with polyester chips at 30 g / min at 290 ° C. at 7 g / min.
It was discharged for a day and determined as the filtration pressure increase per day.

(5) Evaluation of spinneret foreign matter generated in the spinneret: Polyester was made into chips, which was melted at 290 ° C. and discharged from a spinneret with a hole diameter of 0.15 mmφ and 12 holes at 600 m / min. After spinning for 2 days, the height of the layer of deposits generated on the outer edge of the outlet of the die was measured. The larger the height of the deposit layer, the easier the bending of the discharged filament of the polyester melt is, and the lower the moldability of the polyester. That is, the height of the deposit layer generated on the spinneret is an index of the moldability of the polyester.

(6) Flame retardancy: The polyester fiber produced was used to prepare a fabric sample of about 350 mm × 250 mm according to a conventional method. The woven fabric sample was measured according to JIS L-1091.
The afterflame time was measured by the A-1 method (45 ° microburner method). The measurement was performed for each of the three samples and expressed as the average afterflame time. The practically allowable afterflame time is 3 seconds or less.

Example 1 A mixture of 90 parts of dimethyl terephthalate and 60 parts of ethylene glycol was added with tetra-
0.009 parts of n-butyl titanate was charged into a SUS container capable of pressure reaction and pressurized to 0.07 MPa.
After transesterification while raising the temperature from 40 ° C. to 240 ° C., 0.04 part of triethylphosphonoacetate was added to complete the transesterification reaction.

Thereafter, the reaction product was transferred to a polymerization vessel, and 3-
2.7 parts of methyl-phosphico-propionic acid were added,
The temperature was raised to 290 ° C., and a polycondensation reaction was performed in a high vacuum of 65 Pa or less to obtain a polyester having an intrinsic viscosity of 0.60 and a diethylene glycol amount of 1.5% by weight.

The polyester obtained was chipped according to a conventional method. After drying and drying at 160 ° C. for 6 hours, spinning is performed at 290 ° C., the resultant is subjected to a stretching treatment machine having a heating roller at 60 ° C. and a plate heater at 160 ° C., and stretched at a stretching ratio of 4.3 times to obtain 94.35 dtex. A drawn yarn of / 24 filament was obtained. This filament was twisted and subjected to SZ twisting at 2500 T / M, and taffeta was woven using this yarn. The results are shown in Tables 1 and 2.

[Example 2] Polyester and fiber were prepared in the same manner as in Example 1 except that the titanium compound was changed to 0.016 part of titanium trimellitate synthesized by the method of the following Reference Example. Obtained. The results are shown in Tables 1 and 2.

[Reference Example] Method for synthesizing titanium trimellitate An ethylene glycol solution of trimellitic anhydride (0.2
%) Of tetrabutoxytitanium to trimellitic anhydride, and allowed to react for 60 minutes in air at 80 ° C. under atmospheric pressure, then cooled to room temperature and produced with 10 times the amount of acetone. The catalyst was recrystallized, the precipitate was filtered through filter paper, dried at 100 ° C. for 2 hours,
The desired compound was obtained.

Examples 3 to 7 and Comparative Examples 1 to 6 Polycondensation reaction was carried out in the same manner as in Example 1 except that the titanium compound and phosphorus compound (B) were changed to the compounds and values shown in Table 1. And fibers were obtained. The results are shown in Tables 1 and 2.

Comparative Example 7 A mixture of 90 parts of dimethyl terephthalate and 60 parts of ethylene glycol was added with tetra-n.
-Butyl titanate 0.009 parts S which is capable of pressure reaction
Charge in a US container and pressurize at 0.07 MPa. 14
After carrying out the transesterification reaction while raising the temperature from 0 ° C. to 240 ° C., 0.04 part of triethylphosphonoacetate was added to terminate the transesterification reaction.

Thereafter, 10 parts of 3-ethyl-phosphico-propionic acid was added to the reaction product, and 0.053 parts of diantimony trioxide was further added, and the mixture was transferred to a polymerization vessel.
The temperature was raised to 290 ° C., and a polycondensation reaction was performed in a high vacuum of 65 Pa or less to obtain a polyester having an intrinsic viscosity of 0.50 and a diethylene glycol amount of 3.5%. The obtained polyester was made into fibers and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[0066]

[Table 1]

[0067]

[Table 2]

[0068]

As is apparent from Tables 1 and 2, a polymer-soluble titanium compound as a titanium metal is contained in the range of 2 to 10 mol%, and (P / Ti) or (Ti + P) is in an appropriate range. The polyester fiber of the present invention obtained good performance, but when the amount of the polymer-soluble titanium compound added was outside the range of the present invention as a titanium metal element (Comparative Example 1).
Nos. 7 to 7) had poor color tone.

According to the present invention, a flame retardant polyester and a fiber having an excellent color tone are retained by using a Ti catalyst to eliminate the deterioration of the color tone, which is a drawback of the prior art, while maintaining the excellent properties of the polyester. Can be provided.

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Claims (7)

[Claims] 1. At least 80 mol% of the components constituting the polyester is ethylene terephthalate, and the following formula (I): (In the above formula, R is a saturated and linear chain having 10 or less carbon atoms,
Branched or cyclic alkylene group, having 6 to 10 carbon atoms
Or an arylalkylene group having 7 to 10 carbon atoms, and R ₁ represents an alkyl group having 6 or less carbon atoms, an aryl group having 6 to 10 carbon atoms, or an arylalkyl group having 7 to 10 carbon atoms. R ₂ and R ₃ represent an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a hydrogen atom. ) Bifunctional phosphorus compound (A)
As a phosphorus element based on the polyester component.
In a polyester copolymerized with 3 to 1.5% by weight, a titanium compound soluble in the polyester and a phosphorus compound (B) having a maximum number of hydroxyl groups, ester groups or carboxyl groups of 1 or less are contained, The content of the titanium compound soluble in polyester is 2 to 10 mmol as a titanium metal element based on all dicarboxylic acid residue components,
And the following numerical formula (1) and / or (2) 2 ≦ P / Ti ≦ 15 (1) 10 ≦ Ti + P ≦ 100 (mmol%) (2) (where Ti is polyester-soluble titanium contained in polyester) Flame retardance contained so as to satisfy the titanium metal element concentration (mmol%) of the compound, and P represents the phosphorus element conversion concentration (mmol%) of the phosphorus compound (B) contained in the polyester. polyester. 2. The phosphorus compound (B) is represented by the following formula (II): (In the above formula, R ₄ and R ₅ represent the same or different alkyl groups having 1 to 4 carbon atoms, and X represents —CH ₂ — or —
CH (Y) is shown (Y shows an aromatic ring). The flame-retardant polyester according to claim 1, which is a phosphonate compound represented by the formula (1). 3. A titanium compound soluble in the polyester is represented by the following formula (III): (In the above formulas, R _{6 to} R ₉ each represent the same or different alkyl group having 2 to 10 carbon atoms or aryl group having 6 to 15 carbon atoms, and m represents an integer of 1 to 3). A compound, or a compound represented by the above formula (III) and the following formula (IV): The flame retardancy according to claim 1 or 2, which is a product obtained by reacting an aromatic polycarboxylic acid represented by the formula (n represents an integer of 2 to 4) or an acid anhydride thereof. polyester. 4. The flame-retardant polyester according to claim 1, wherein dimethyl terephthalate is 80 mol% or more of all dicarboxylic acid components in the raw material as a raw material starting material for ethylene terephthalate. 5. A method in which a part or the whole amount of a titanium compound soluble in the polyester is added before the start of the transesterification reaction so that two kinds of catalysts, that is, a transesterification reaction catalyst and a polycondensation reaction catalyst, are used in combination. Item 5. The flame-retardant polyester according to any one of items 1 to 4. 6. The transesterification reaction is 0.05 to 0.2.
The flame-retardant polyester according to claim 5, which is produced under a pressure of 0 MPa. 7. A flame-retardant polyester fiber obtained by melt spinning the polyester according to any one of claims 1 to 6.