JP2003119665A - Polyester fiber and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester fiber having good tint (b value), special micropores, excellent in hygroscopicity, water absorption properties, dry feeling and excellent in formability with generating very small amount of deposits to a spinneret even when carrying out a continuous spinning through the spinneret for a long time and provide a method for producing the same. SOLUTION: This method for producing the polyester fiber is to use a polyester-producing catalyst containing a specific titanium compound and a phosphorus compound, blend a specific metal sulfonate at an arbitrary stage until finishing the melt spinning of the polyester, bring the obtained polyester composition to be a fiber and treat the fiber with the aqueous solution of an alkali compound to remove at least a part of the metal sulfonate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester fiber and a method for producing the same, more specifically, a polyester having a good color tone (color b value) using a catalyst for producing a polyester containing a specific titanium compound and phosphorus compound. The present invention relates to a polyester fiber having excellent dry feeling with special fine pores and a method for producing the same.

[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 therefore, fibers, films and other molded products are obtained. Widely used in.

For example, polyethylene terephthalate is usually obtained by directly esterifying terephthalic acid and ethylene glycol, transesterifying a lower alkyl ester of terephthalic acid such as dimethyl terephthalate with ethylene glycol, or terephthalic acid and ethylene. Reacting with oxide to form an ethylene glycol ester of terephthalic acid and / or a low polymer thereof,
Then, this reaction product is heated under reduced pressure in the presence of a polymerization catalyst to carry out a polycondensation reaction until a predetermined degree of polymerization is achieved. Also, polyethylene naphthalate,
Polytrimethylene terephthalate and polytetramethylene terephthalate are also produced by the same method as described above.

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. As a polycondensation catalyst for polyethylene terephthalate, antimony compounds are most widely used because of having excellent polycondensation catalyst performance and obtaining a polyester having a good color tone.

However, when an antimony compound is used as a polycondensation catalyst, when polyester is continuously melt-spun for a long period of time, foreign matter (hereinafter, sometimes simply referred to as die foreign matter) adheres and deposits around the mouth of the die. However, there is a problem of moldability that a bending phenomenon (bending) of the flow of the molten polymer occurs, which causes fuzz and / or yarn breakage in the spinning and drawing steps.

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 above-mentioned deposition of foreign matter on the spinneret is prevented. Although the problem of moldability due to the problem can be solved, a new problem arises in that the obtained polyester itself is colored yellow and the melt thermal stability is poor.

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 color tone (color b value) of polyester can be improved by adding the cobalt compound, but the addition of the cobalt compound lowers the melt heat stability of the polyester and facilitates decomposition of the polymer. 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 polymer having a good color tone (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. Indeed, according to this method,
Although the melt heat stability of polyester is improved to some extent, the color tone of the obtained polymer is not sufficient,
Therefore, further improvement in polymer color tone is desired.

Further, in JP-A-7-138354, it has been proposed to use a complex of a titanium compound and a phosphorus compound as a catalyst for polyester production. According to this method, the melting heat stability is improved to some extent. Though
The color tone of the obtained polymer is not sufficient.

Incidentally, these titanium-phosphorus-based catalysts often remain as foreign substances in the polyester polymer, and it has been desired to solve this problem.

Further, since polyester fibers are generally hydrophobic, their use is restricted in fields requiring water absorbency and hygroscopicity. In particular, in order to give an unpleasant feeling of attraction due to stickiness during sweating, 100% of polyester fiber is rarely used in the field of inner garments such as shirts and blouses and inner garments such as underwear, and it is used mixed with cotton and hemp It is only being done.

According to Japanese Patent Publication No. 63-00545,
A specific sulfonic acid metal salt is provided for the purpose of providing a polyester fiber which is not sticky even in a wet state caused by sweating and has an excellent dry feeling while maintaining the excellent easy-care property originally possessed by the polyester fiber. By subjecting the polyester fiber blended with to the alkali weight reduction treatment, a large number of fine pores communicating not only with the surface of the polyester fiber but also inside the fiber are provided, and as a result, a fiber with a dry feeling superior to cotton can be obtained. However, since the fibers themselves using polyethylene terephthalate are soft due to their chemical modification, they are easily affected by the above-mentioned foreign substances in the die.

Although this problem can be solved by using a method that does not use antimony as a polymerization catalyst as described above, this method reduces the color of the yarn.
It is difficult to actually use it. Therefore, without using antimony as a polymerization catalyst, and hue, hygroscopicity, water absorption,
There has been a demand for a polyester fiber which is excellent in moldability and has a very small amount of spinneret deposits even when it is continuously spun through a spinneret for a long time in addition to being excellent in dry feeling, and a method for producing the same.

[0015]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the above-mentioned prior art, and to obtain a good color tone (b) using a catalyst for polyester production containing a specific titanium compound and phosphorus compound. Value), with special micropores, excellent hygroscopicity, water absorption, and dry feeling, and the amount of spinneret deposits is extremely high even when spun continuously for a long time through the spinneret. The object is to provide a polyester fiber having a very small amount and excellent in moldability, and a method for producing the same.

[0016]

As a result of intensive studies made by the present inventors in view of the above-mentioned prior art, the inventors have found that the above object can be achieved when a specific catalyst for producing polyester is used, and complete the present invention. Came to.

That is, the object of the present invention is to produce a fiber comprising a polyester having ethylene terephthalate as a main repeating unit, in which the titanium compound soluble in the polyester is based on the total dicarboxylic acid component constituting the polyester. A polyester polymer containing 2 to 15 mmol% of titanium metal element and satisfying the following general formulas (1) and (2) is added at 0.1% at any stage until the melt spinning of the polyester is completed.
At least 25 mol% of a sulfonic acid metal salt represented by the following general formula (I) is added, and then the fiber obtained by melt spinning is treated with an aqueous solution of an alkali compound to obtain at least the sulfonic acid metal salt. This can be achieved by a method for producing a polyester fiber, which is characterized in that a part thereof is removed.

[0018]

[Equation 2]

[0019]

[Chemical 5]

[0020]

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

The polyester of the present invention contains a titanium compound soluble in the polymer in an amount of 2 to 15 mmol% as a titanium metal element based on all dicarboxylic acid components, and satisfies the following general formulas (1) and (2). There is a need.

[0022]

[Equation 3] Examples of the phosphorus compound used in the present invention include phosphoric acid, phosphorous acid, phosphonic acid, phosphonate compounds and derivatives thereof, and these may be used alone or in combination of two or more. Good. Among these phosphorus compounds, a phosphonate compound represented by the following general formula (II) is particularly preferable.

[0023]

[Chemical 6] Examples of the above-mentioned phosphonate compound include dimethyl-, diethyl-, dipropyl- and dibutyl esters of phosphonic acid, and specifically, carbomethoxymethanephosphonic acid, carboethoxymethanephosphonic acid, carbopropoxymethanephosphonic acid, carboptoxy. Examples thereof include methanephosphonic acid, carbomethoxy-phosphono-phenylacetic acid, carboethoxy-phosphono-phenylacetic acid, carboprotoxy-phosphono-phenylacetic acid, carbobutoxy-phosphono-phenylacetic acid and the like.

The reason why the above phosphonate compound is preferable is that the catalyst activity of the titanium compound during the polycondensation reaction is relatively high because the reaction with the titanium compound proceeds relatively slowly as compared with the phosphorus compound which is usually used as a stabilizer. Since the duration is long, 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 this patent, it has the property of not easily impairing the thermal stability of the polyester. Is.

The phosphorus compound may be added at any time after the transesterification reaction or the esterification reaction is substantially completed. For example, the polycondensation reaction may be performed under atmospheric pressure before the polycondensation reaction is started. It may be added under reduced pressure after the start of the above, at the end of the polycondensation reaction, or after the end of the polycondensation reaction, that is, after the polymer is obtained.

In the present invention, it is necessary to use a titanium compound which is soluble in the polymer, as the titanium compound used, from the viewpoint of reducing foreign matter caused by the catalyst. The titanium compound is not particularly limited, and examples thereof include titanium compounds that are commonly used as polycondensation catalysts for polyesters, such as titanium acetate and tetra-n-butoxytitanium. Particularly preferred are the following general formula (III). A compound represented by
Alternatively, it is a product obtained by reacting a compound represented by the general formula (III) with an aromatic polycarboxylic acid represented by the following general formula (IV) or an anhydride thereof.

[0027]

[Chemical 7]

[0028]

[Chemical 8] Examples of the titanium compound represented by the general formula (III) include R
3, R3 ′, R3 ″, and R3 ′ ″ are the same or different, and are not particularly limited as long as they are an alkyl group and / or a phenyl group, tetraisopropoxy titanium,
Tetrapropoxy titanium, tetra-n-butoxy titanium, tetraethoxy titanium, tetraphenoxy titanium,
Octaalkyl trititanate, hexaalkyl dititanate, etc. are preferably used.

The aromatic polycarboxylic acid represented by the general formula (IV) or its anhydride reacted as the compound includes phthalic acid, trimellitic acid, hemimellitic acid, pyromellitic acid and their anhydrides. The thing is used preferably.

When the above titanium compound is reacted with an aromatic polyvalent carboxylic acid or its anhydride, a part of the aromatic polyvalent carboxylic acid or its anhydride is dissolved in a solvent, and the titanium compound is added dropwise thereto. Then, the reaction may be performed at a temperature of 0 to 200 ° C. for at least 30 minutes.

The polyester of the present invention must contain a titanium compound soluble in the polymer as a titanium metal element in an amount of 2 to 15 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 the polyester having a target molecular weight cannot be obtained.

Further, the titanium metal element is 15 mmol%.
On the other hand, if it exceeds the above range, the thermal stability will be lowered, and the molecular weight will be greatly reduced during the fiber production, 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 12 mmol%, more preferably in the range of 3 to 10 mmol%. The term "titanium compound soluble in the polymer" as used herein means that titanium contained in the titanium dioxide particles is not included, and "titanium metal element amount" means the first-stage reaction by the transesterification reaction. When performing, the total amount of the titanium compound used as the transesterification reaction catalyst and the titanium compound used as the polycondensation reaction catalyst is shown.

The polyester in the present invention must be produced by using a titanium compound as a catalyst and a phosphorus compound as a stabilizer, and satisfy both of the following formulas (1) and (2).

[0034]

[Equation 4] When (P / Ti) is less than 2, the hue is remarkably yellowed, which is not preferable. Further, when (P / Ti) exceeds 15, the polymerization reactivity of the polyester is significantly lowered, and 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. However, when it is in the proper range, it is possible to obtain an unprecedented effect like the present invention. it can. On the other hand, if (Ti + P) is less than 10, productivity in the yarn making process is significantly reduced, and satisfactory performance cannot be obtained. Further, when (Ti + P) exceeds 100, a small amount of foreign matter due to the catalyst is generated, which is not preferable.

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

In general, a production method using an aromatic dicarboxylic acid typified by terephthalic acid as a raw material for a polyester having ethylene terephthalate as a main repeating unit and an ester-forming derivative of an aromatic dicarboxylic acid typified by dimethyl terephthalate are used as raw materials. There are two known methods used as.

The polyester in the present invention is not particularly limited depending on its production method, but is preferably a production method via a transesterification reaction in which dimethyl terephthalate accounts for 80 mol% or more of the starting material of ethylene terephthalate units. The production method using dimethyl terephthalate as a raw material has an advantage that the phosphorus compound 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 a raw material, the addition amount of the titanium compound can be reduced, and a part and / or the whole amount of the titanium compound is added before the start of the transesterification reaction, and the transesterification catalyst and A production method in which two catalysts of the condensation reaction catalyst are also used is preferable, and a method in which the transesterification reaction is carried out under a pressure of 0.05 to 0.20 MPa is more preferable.

The pressure during the transesterification reaction is 0.05 M
If it is less than or equal to pa, the promotion of the reaction due to the catalytic action of the titanium compound is not sufficient. On the other hand, if it is more than 0.20 MPa, the content of diethylene glycol generated as a by-product in the polymer is remarkably increased, and the thermal stability of the polymer, etc. Is inferior in characteristics.

Furthermore, in order to finely adjust the color of the obtained polyester, an azo type, triphenylmethane type, quinoline type,
A color-matching agent composed of one or more of organic blue pigments such as anthraquinone type and phthalocyanine type and inorganic blue pigments can be added. In the production method of the present invention, naturally, it is not necessary to use an inorganic blue pigment containing cobalt or the like which lowers the melt thermal stability of the polyester as a color-matching agent, and thus the resulting polyester is substantially It is preferably free of cobalt.

In the following general formula (I) showing the sulfonic acid metal salt used in the present invention, Ar is an aromatic group, and among them, a benzene ring or a naphthalene ring is preferable. R ₄ is an ester-forming functional group, and —COOR ′ (wherein R ′ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group).
Or _{-CO- (O-CH 2) l} } - p OH (. However, l is an integer of 2 or more, P is an integer of 1 or more) and the like are preferable. M and M ′ are metals, and M is preferably an alkali metal or an alkaline earth metal, among which Li, Na, K, Ca
_1/2 and Mg _1/2 are particularly preferable. M'is preferably an alkali metal, an alkaline earth metal, Mn _1/2 , Zn _1/2 , among which Li, Na, K, Ca _1/2 , Mg _1/2 , B
a _1/2 is particularly preferable. M and M'may be the same or different. m is an integer of 0 to 4, n is an integer of 1 to 5, and m + n is an integer of 1 to 5.

A preferred specific example of the sulfonic acid metal salt is Na 3-carbomethoxybenzenesulfonate.
-5-carboxylic acid Na, 3-carbomethoxy benzene sulfonic acid Na-5 monocarboxylic acid K, 3-carbomethoxy benzene sulfonic acid K-5-carboxylic acid K, 3-hydroxyethoxy carbonyl benzene sulfonic acid Na
-5-carboxylic acid Na, 3-carboxy benzene sulfonic acid Na-5-carboxylic acid Na, 3-hydroxyethoxy carbonyl benzene sulfonic acid Na-5-carboxylic acid Mg1 _{/ 2} , benzene sulfonic acid Na-3,5 -Di (carboxylic acid Na), benzenesulfonic acid Na- 3,5
-Di (carboxylic acid Mg _1/2 ), benzenesulfonic acid Na
-3-carboxylic acid Na, 3-carbomethoxynaphthalene-1-sulfonic acid Na-7-carboxylic acid Na, naphthalene-1-sulfonic acid Na-3,7-di (carboxylic acid M
g _1/2 ) and the like.

The above sulfonic acid metal salts may be used alone or in combination of two or more. The addition timing may be any stage before the spinning step of melt spinning the polyester is completed, for example, addition and mixing in the raw material of the polyester, or addition during the synthesis of the polyester,
It may also be added during the period from the completion of synthesis to the melt spinning. In any case, it is preferable to mix them in a molten state after the addition.

If the amount of the above-mentioned metal sulfonate is too small, the dry feeling of the finally obtained polyester fiber will be insufficient. On the contrary, if the amount is too large, the addition time will be before the completion of polyester synthesis. It is difficult to obtain a polyester having a sufficient degree of polymerization, and troubles are likely to occur during spinning when the addition time is from after the synthesis to before the melt spinning. Therefore, the addition amount should be in the range of 0.1 to 25 mol% with respect to the acid component constituting the polyester to be added, preferably in the range of 0.3 to 15 mol%, and particularly 0.5 to A range of 5 mol% is particularly preferred.

In order to melt-spin the modified polyester mixed with the sulfonic acid metal salt into a solid fiber, it is not necessary to employ a special method, and a melt-spinning method of a polyester solid fiber is arbitrarily adopted. It The shape of the fiber to be spun out here in the cross section may be circular or irregular, and the single fiber fineness is not particularly limited, but if it is about 1 dtex or less, not only dry feeling,
Depending on the application, it is preferably about 1 dtex or less, because it also has excellent water absorption and does not puncture the skin.

Further, when spinning, a modified polyester containing the above-mentioned metal sulfonate and an unmodified polyester containing no metal sulfonate are used, and the modified polyester is used as a sheath component and the unmodified polyester is used as a core component. A core-sheath type composite fiber may be used, or a modified polyester and an unmodified polyester may be used to form a two-layer or more multilayer side-by-side type composite fiber.

In order to remove at least a part of the above-mentioned metal salt of sulfonic acid from the polyester fiber thus obtained, after subjecting it to a heat treatment for drawing or false twisting, etc., if necessary, further to a cloth. After that, it can be easily carried out by immersing in an aqueous solution of an alkali compound.

As the alkaline compound used here,
Examples thereof include sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, sodium carbonate, potassium carbonate and the like. Of these, sodium hydroxide and potassium hydroxide are particularly preferable.

The concentration of the aqueous solution of such an alkali compound varies depending on the kind of the alkali compound, the treatment conditions and the like, but is usually preferably in the range of 0.01 to 40% by weight, and particularly preferably in the range of 0.1 to 30% by weight. Is preferred. The processing temperature is preferably in the range of room temperature to 100 ° C, and the processing time is 1 minute to 4
It is usually done within a time range. By thus treating with an aqueous solution of an alkali compound, the polyester is selectively eluted together with the sulfonic acid metal salt, and it is possible to form a large number of fine pores communicating with the outside not only on the fiber surface but also on the fiber inner surface. , Comes to exhibit an excellent dry feeling.

The polyester obtained by the method of the present invention usually has an L value of 80.
It is 0 or more and the b value is in the range of -2.0 to 5.0. When the L value of the polyester is less than 80.0, the whiteness is low, and thus a molded product with high whiteness that can be put to practical use may not be obtained.

Further, when the b value is less than -2.0, the polyester has less yellowishness but more blueness, while b
When the value exceeds 5.0, the yellowness of the obtained polyester becomes strong, and it may not be possible to use it for the production of a practically useful molded product. The L value of the polyester obtained by the method of the present invention is preferably 82 or more, particularly preferably 83 or more, and the preferable range of the b value is -1.0 to 4.
5, and particularly preferably 0.0 to 4.0.

The L value and b value of the polyester obtained by the method of the present invention are measured by the following methods.
That is, a polyester sample was subjected to 1 at 290 ° C under vacuum.
It was melted for 0 minutes, and this was molded into a plate having a thickness of 3.0 ± 1.0 mm on an aluminum plate, and the plate was immediately quenched in ice water.
After being dried for 1 hour and then subjected to crystallization treatment, the plate was placed on a white standard plate for adjusting the color difference meter, and the color tone of the surface of the sample plate was measured by Minolta Hunter color difference meter C.
It measured using R-200.

The polyester of the present invention is substantially free of cobalt atoms derived from the cobalt compound for color matching. Polyesters containing cobalt atoms have the drawbacks of low melt heat stability and easy decomposition. The term "substantially free" as used herein means that a cobalt compound is not used as a color-matching agent or a polycondensation catalyst,
Therefore, it means that the obtained polyester does not contain a cobalt atom derived from the above cobalt compound. Therefore, the polyester of the present invention may contain a cobalt atom derived from the cobalt compound added for the purpose other than the color-matching agent and the catalyst.

The intrinsic viscosity of the polyester in the present invention may be appropriately selected, but is preferably in the range of 0.55 to 1.0. When the intrinsic viscosity is within this range, melt molding is easy and the strength of the molded product is high. The more preferable range of the intrinsic viscosity is 0.60 to 0.90.
And particularly preferably 0.62 to 0.80.

[0055]

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. However, as described above, the intrinsic viscosity, hue,
The titanium content, the number of foreign matters, the thermal stability of fusion and the 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 3 for the orthochlorophenol solution.
It was determined from the viscosity value measured at 5 ° 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 on 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) Dynamic friction coefficient ratio measuring method: temperature 20
A test cloth (weight: W grams) with a width of 10 cm and a length of 10 cm was placed on a table placed in a box whose temperature was controlled at 80 ° C and a relative humidity of 80%. ) Is fixed on the bottom of the plate, and a load of 50 grams is further applied on the plate-like pedestal. Guide the string connected to the tip of the pedestal from the horizontal direction vertically through the bearing to the strain gauge attached to the other end of the string, and raise the strain gauge at a constant speed to make the test cloth at a speed of 10 mm / min. Automatically record tensile stress by sliding on cowhide, and stick-slip (sli)
The average tensile stress F (gram) of p) is read, and the dynamic friction coefficient μ is calculated by the following formula.

[0060]

[Equation 5] The dynamic friction coefficient ratio is determined as the ratio of the dynamic friction coefficient in the wet state measured by the above method with a certain amount of water retained in the test cloth and the dry friction coefficient measured in the same manner with the test cloth in an absolutely dry state.

FIG. 1 is a diagram showing an example of the relationship between the dynamic friction coefficient ratio and the water retention rate measured by this method. Curve A is a knitted fabric using the polyester fiber produced by the method of the present invention (Example 1), Curve B is a knitted fabric using polytrimethylene terephthalate fibers which have not been copolymerized in the present invention (Comparative Example 1), curve C is a fabric using 40-count cotton yarn, and curve D is a fabric using ordinary polyethylene terephthalate fibers. It shows the measurement results for (Comparative Example 3).

As is apparent from FIG. 1, the polyester fiber obtained by the method of the present invention has a smaller difference from the dynamic friction coefficient ratio value of 1.0 than that of ordinary polyester fiber or cotton, and has about 100%. It can be seen that even in the water retention rate, the level of the dynamic friction coefficient at the time of absolutely dryness is maintained, and it has an excellent dry feeling superior to that of cotton.

The water retention rate referred to here is obtained from the following equation.

[0064]

[Equation 6]

(5) Layer of deposits generated on the spinneret: Polyester is made into chips, which are melted at 290 ° C.,
It was discharged from a spinneret having a hole diameter of 0.15 mmφ and 12 holes, and was spun at 600 m / min for 2 days, and the height of a layer of deposits generated on the outer edge of the discharge port of the spinneret 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.

[Example 1] Dimethyl terephthalate 194
Parts by weight, 124 parts by weight of ethylene glycol and tetra-
0.017 parts by weight of n-butyl titanate was put into a stainless steel container capable of pressure reaction, and transesterification reaction was performed at 220 ° C. under pressure of 0.07 MPa, and then triethylphosphonoacetate 0 was added to the reaction mixture. .08
Parts were added to complete the first stage reaction.

Then, the above reaction mixture was placed in a polycondensation flask equipped with a rectification column, and 0.0002 parts by weight of terazol blue as a color-adjusting agent, Na-5-carboxylic acid 3-hydroxycarbonylbenzenesulfonate was added to this reaction mixture. Acid N
7.7 parts of a 25% ethylene glycol solution of a and 2.9 parts of a 20% ethylene glycol slurry of titanium dioxide were added.

Next, from 1 kPa to 0.
Decompress to 1 kPa and simultaneously 230 over 1 hour 30 minutes
The temperature was raised from ℃ to 280 ℃. Under reduced pressure of 0.1 kPa or less, polymerization temperature is 280 ° C., and further 3 hours, total 4 hours 30
Polymerization was carried out to obtain a polymer having an intrinsic viscosity of 0.640, which was then made into chips by a conventional method.

This chip was dried by a conventional method to give a pore size of 0.
Using a spinneret with 36 3 mm circular spinning holes,
Melt spinning was performed according to a conventional method to obtain an undrawn yarn of 340 dtex / 36 filaments. Then, this unstretched yarn was stretched 4.2 times according to a conventional method to obtain 81 dtex / 36 filament.

The obtained multifilament was knitted into a 28G tricot half knitted fabric having a density of 52 filaments / inch × 34 filaments / inch, and after scouring and presetting according to a conventional method, a weight loss ratio of 20% was obtained. % Aqueous sodium hydroxide at boiling temperature. The relationship between the water retention rate and the dynamic friction coefficient ratio of this cloth was as shown by the curve B in FIG. 1, and it had an excellent dry feeling. Other results are shown in Table 1.
It was shown to.

Example 2 A polycondensation reaction was carried out in the same manner as in Example 1 except that the titanium compound was changed to 0.031 part of titanium trimellitate synthesized by the method of the following reference example to obtain polyester and fiber. Obtained. The results are shown in Table 1.

Reference Example Titanium trimellitate synthesis method: To an ethylene glycol solution of trimellitic anhydride (0.2%), tetrabutoxy titanium was added in an amount of 1/2 mol with respect to trimellitic anhydride, and the mixture was kept in air. The mixture is kept under pressure at 80 ° C. and reacted for 60 minutes, then cooled to room temperature, the produced catalyst is recrystallized with 10 times amount of acetone, the precipitate is filtered through a filter paper, and 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 were changed to the compounds and values shown in Table 1 to obtain polyester and fiber. Obtained. The results are shown in Table 1.

[Comparative Example 7] Dimethyl terephthalate 194
In a mixture of parts by weight and 124 parts by weight of ethylene glycol,
0.017 parts by weight of tetra-n-butyl titanate was charged into a stainless steel container capable of pressure reaction, and 0.07MP
After carrying out the pressure of a and conducting a transesterification reaction while raising the temperature from 140 ° C. to 240 ° C., 0.08 part of triethylphosphonoacetate was added to terminate the transesterification reaction.

Thereafter, 0.101 parts by weight of diantimony trioxide was added to the reaction product, 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 0.2 mmHg or less to obtain a polyester having an intrinsic viscosity of 0.640 and a diethylene glycol amount of 1.4% by weight.

The obtained polyester was made into fibers in the same manner as in Example 1. The results are shown in Table 1.

[0077]

[Table 1]

[0078]

According to the polyester fiber and the method for producing the same of the present invention, the polyester fiber has excellent color tone and has special fine pores,
Polyester fiber excellent in hygroscopicity, water absorption, dry feeling, and further excellent in moldability due to extremely small amount of spinneret deposits even when spun continuously for a long time through a spinneret, and a method for producing the same Can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a dynamic friction coefficient ratio and a water retention rate measured by this method.

[Explanation of Codes] A: A curve representing the relationship between the dynamic friction coefficient ratio and the water retention rate measured for a knitted fabric (Example 1) using the polyester fiber produced by the method of the present invention. B: A curve representing the relationship between the dynamic friction coefficient ratio and the water retention rate measured for a knitted fabric (Example 2) using the polyester fiber produced by the method of the present invention. C: A curve showing the relationship between the dynamic friction coefficient ratio and the water retention rate, which was measured on the fabric using the # 40 cotton yarn. D: A curve showing the relationship between the dynamic friction coefficient ratio and the water retention rate measured for a knitted fabric using the polyester fiber produced according to Comparative Example 1.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J029 AA03 AB04 AC01 AE02 BA03                       CB06A HA01 HB01 HB03A                       JA253 JB131 JB171 JC373                       JC573 JF321 KB02 KB04                       KB05 KB25 KD06 KE02 KE06                 4L031 AA18 AB01 BA11 CA01 DA00                       DA01                 4L035 DD07 EE20 GG02

Claims (7)

[Claims] 1. When producing a fiber comprising a polyester having ethylene terephthalate as a main repeating unit, the titanium compound soluble in the polyester is 2 to 3 as a titanium metal element based on all dicarboxylic acid components constituting the polyester. It contains 15 mmol%,
In addition, a polyester polymer satisfying the following general formulas (1) and (2) can be added with the following general formula (I) in an amount of 0.1 to 25 mol% at any stage until the completion of melt spinning of the polyester. Production of a polyester fiber, characterized in that the sulfonic acid metal salt represented by the formula is blended and the fiber obtained by melt spinning is treated with an aqueous solution of an alkali compound to remove at least a part of the sulfonic acid metal salt. Method. [Equation 1] [Chemical 1] 2. A phosphorus compound having the following general formula (II):
The production method according to claim 1, wherein a phosphonate compound represented by: is added. [Chemical 2] 3. A titanium compound which is soluble in polyester,
A compound represented by the following general formula (III) or a compound represented by the following general formula (III) was reacted with an aromatic polyvalent carboxylic acid represented by the following general formula (IV) or an anhydride thereof. The production method according to claim 1, which is a product. [Chemical 3] [Chemical 4] 4. A titanium compound soluble in polyester,
The production method according to claim 3, wherein a part of the total addition amount and / or the total amount thereof is added into the reaction system before the start of the transesterification reaction to serve both as the transesterification reaction catalyst and the polycondensation reaction catalyst. 5. The production method according to claim 1, wherein dimethyl terephthalate accounts for 80 mol% or more of the starting material of ethylene terephthalate units. 6. The transesterification reaction is performed in the range of 0.05 to 0.2.
The manufacturing method according to claim 1, which is carried out under a pressure of 0 MPa. 7. A polyester fiber obtained by the method according to claim 1.