JP2003027336A - Method for producing polyester conjugate fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a two-component conjugate fiber excellent in spinnability and scarcely causing problems such as occurrence of white powder in false twist step and yarn breakage. SOLUTION: In this method for producing the polyester conjugate fiber, the conjugate fiber uses two components A and B in which alkali-reducing speeds are different, and a polyester containing >=90% ethylene terephthalate and obtained by a direct continuous polymerization method so that a ratio of maximum value [η]max of intrinsic viscosity to minimum value [η]min thereof satisfies the formula 1.0<=[η]max/[η]min<=1.02 is used as the component A, and a readily alkali water-soluble polyester obtained by a direct continuous polymerization method so that a ratio of maximum value [η]max of intrinsic viscosity to minimum value [η]min thereof satisfies the formula 1.0<=[η]max/[η]min<=1.02 is used as the component B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a bicomponent composite fiber which is divided into ultrafine fibers or hollow fibers by completely dissolving and removing one component in an alkali weight reduction step. More specifically, spinning process, drawing process,
The present invention relates to a method for producing a bicomponent composite fiber which has good heat resistance in the false twisting process and the weaving process and does not cause problems such as yarn breakage and fluff.

[0002]

2. Description of the Related Art Conventionally, splittable conjugate fibers containing an easily soluble alkaline water polyester as a component have been manufactured for the purpose of obtaining ultrafine yarns having extremely fineness, and are disclosed in JP-B-63-20939 and JP-B-8-14042. As disclosed in the publication, at least a part of the split components is eluted by alkali treatment to form split yarns, which are used for a suede-like high density woven or knitted fabric or a silk-like woven or knitted fabric having an elegant luster and a soft texture.

Further, it is used for woven or knitted fabrics in which a readily soluble alkaline water-soluble polyester is used as a core component, and after the alkali reduction treatment, hollowed out or grooves are formed to make hydrophobic polyester fibers absorb water and dry quickly. ing.

As the alkali water easily soluble polyester,
A metal sulfonate-containing isophthalic acid component as an acid component and a polyalkylene glycol having a high average molecular weight as a glycol component are mainly used. For example, a composite fiber using the polyester is disclosed in Japanese Patent No. 254
6802 and Japanese Patent Publication No. 63-20939.

Conventionally, as a method for producing such an easily water-soluble polyester, a transesterification method using dimethyl terephthalate (hereinafter referred to as a DMT method) is mainly used as described in JP-A-62-89725, A batch type manufacturing method is generally used in the DMT method. Further, as a manufacturing method relating to a direct polymerization method using terephthalic acid (hereinafter referred to as a direct weight method), there is a method described in JP-B-58-45971, which is also a batch type manufacturing method.

When the batch production method is used, the polymer viscosity at the start of extrusion differs from the polymer viscosity at the end of extrusion due to the time-dependent change of polymer extrusion, and when the number of batches increases, the residual polymer in the kettle deteriorates. However, there is a problem in that the polymer is mixed in and the difference in polymer physical properties between batches becomes large. In order to improve this, measures such as reducing the number of batches and blending polymer pellets are taken, but when composite fibers are spun using this polymer, fluff and yarn breakage due to polymer physical property irregularities occur frequently. There was a problem.

On the other hand, in Japanese Unexamined Patent Publication No. 6-306734, a cationic dyeable polyester is used as an ultrafine fiber after treated with an alkaline solution. In the case of the ultrafine fibers,
It is described that since it can be dyed with a cationic dye, it can be sufficiently darkened even if it is made extremely fine.

However, even in the composite fiber, the polyester used as the easily soluble component in alkaline water and the component capable of being dyed with cation can be obtained only by the batch type polymerization method, so that the spinning operability is unstable. In addition, there are process problems such as the generation of white powder in the false twisting process and the like, and because the polymer properties are unstable, only composite fibers of poor quality such as dyeing spots, warps and wefts can be obtained.

[0009]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, has excellent spinning operability, and is low in cost of a bicomponent composite fiber having few problems such as white powder generation and yarn breakage in the false twisting process. The challenge is to provide.

[0010]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that in a two-component composite fiber having different alkali weight loss rates, the component A remaining after the alkali weight reduction treatment is carried out. , And a polyester that is an easily soluble component in alkaline water are directly produced by a continuous polymerization method, and if the variation in the intrinsic viscosity of the obtained polyester is reduced, the spinning operability is excellent, and the yarn breaks in the post-process such as the false twist process. , And found that problems such as white powder are eliminated.

That is, the constitution of the present invention is a composite fiber using two components having different alkali weight loss rates, and 90% or more of the component A is ethylene terephthalate, and the maximum value [η] max and the minimum value of the intrinsic viscosity are the same. The ratio of the value [η] min is 1.0
Using a polyester obtained by a direct continuous polymerization method satisfying ≦ [η] max / [η] min ≦ 1.02, as the component B, the maximum value [η] max and the minimum value [η] min of the intrinsic viscosity are A method for producing a polyester composite fiber, characterized in that an alkali water readily soluble polyester obtained by a direct continuous polymerization method having a ratio of 1.0 ≦ [η] max / [η] min ≦ 1.02 is used It is a thing.

The component A is obtained by a direct continuous polymerization method containing a metal sulfonate group-containing isophthalic acid component in an amount of 1.0 to 3.0 mol%, and has a maximum intrinsic viscosity [η] max and a minimum intrinsic viscosity [η]. The ratio of η] min is 1.0 ≦ [η] ma
The present invention relates to a method for producing a polyester conjugate fiber, which is a cationic dyeable polyester satisfying x / [η] min ≦ 1.02.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
In the present invention, the polyester polymer of the component B which is easily soluble in alkaline water is dimethyl 5-metal sulfoisophthalate (hereinafter referred to as SIPM) or a compound obtained by esterifying the dimethyl group of SIPM with ethylene glycol (hereinafter referred to as SI
Referred to as PE) and a polyester alkylene glycol.

The metal in SIPM or SIPE may be sodium, potassium, lithium, etc., with sodium being most preferred. Further, in the direct continuous polymerization method, it is preferable to use SIPE for slurry stability.

The copolymerization rate of SIPE is preferably 2.0 to 3.0 mol% in the acid component of the polymer. Within this range, the solubility in alkaline water is excellent and the operability in the melt spinning process is also excellent.

The polyalkylene glycol, which is one of the constituents of the readily soluble component B polymer in alkaline water, is represented by the general formula HO (C _n H _2n O) _m H (where n and m are positive integers). Among them, polyethylene glycol of n = 2 (hereinafter referred to as PEG) is versatile and most preferable.

The molecular weight of PEG used in the present invention is 100.
0 to 10000 is preferable. Within this range, hydrolysis does not occur during melt spinning and the workability is good. Also, the polymerization reactivity is excellent.

The amount of PEG copolymerized is preferably 9.0 to 13.0% by weight based on the polymer. Within this range, the solubility in alkaline water is excellent, and the heat resistance of the polymer is good.

What is most important in the present invention is that the intrinsic viscosity of the component B easily soluble in alkaline water is the maximum value [η] of the intrinsic viscosity.
The ratio of max to the minimum value [η] min is 1.0 ≦ [η] max /
[Η] min ≦ 1.02. [Η] max / [η] min
When the value is out of the above range, yarn breakage frequently occurs during melt spinning, and the spinnability of the spinneret is shortened due to poor spin filterability, resulting in poor operability.

The polymer of the component B which is easily soluble in alkaline water is produced by a direct continuous polymerization method, and its outline will be described below with reference to the drawings. (FIG. 1) is a schematic diagram showing a direct continuous polymerization apparatus for producing a polymer of a component B easily soluble in alkaline water. After slurrying terephthalic acid and glycol in the slurry tank 1, a metal sulfonate group-containing isophthalic acid compound is charged into 1 through the charging port a to slurry. Then, the slurry is continuously supplied to the first esterification tank 2 to cause an esterification reaction to form an oligomer. Further, the produced oligomer is sequentially supplied to the second esterification tank 3, and polyalkylene glycol is added at the charging port b. After that, the oligomer is successively and continuously supplied to the polymerization tank 4 and the polymerization reaction is continuously performed under a vacuum up to a predetermined polymerization degree. A polymer having a predetermined degree of polymerization is extruded from a polymer discharge port (not shown) of the polymerization tank 4 through pores into a water bath, and the extruded rope is made into chips by a cutter.

In the composite fiber of the present invention, the component A having a slow alkali weight loss rate and remaining after the weight loss treatment is an aromatic dicarboxylic acid such as isophthalic acid, an aliphatic dicarboxylic acid such as adipic acid or sebacic acid, or an ester thereof. And ethylene glycol, diethylene glycol,
A polyester in which 90 mol% or more of the constitutional unit composed of a diol compound such as 1,4-butanediol is polyethylene terephthalate is used.

Particularly, in the case of a so-called cationic dyeable polyester containing 1.0 to 3.0 mol% of a metal sulfonate group-containing isophthalic acid component as an acid component, the polyester obtained by the direct continuous polymerization method as in the component B is used. It is preferable to use.

Here, in the cationic dyeable polyester polymer, as shown in FIG. 1, terephthalic acid and glycol are slurried in the slurry tank 1 and then the metal sulfonate group-containing isophthalic acid compound is introduced into the charging port a. 1 to 1 to make a slurry, and then the slurry is continuously supplied to the first esterification tank 2 to cause an esterification reaction to form an oligomer, and further the generated oligomer is sequentially supplied to the second esterification tank 3. Then, thereafter, the oligomer is sequentially and continuously supplied to the polymerization tank 4 to continuously carry out a polymerization reaction under vacuum to a predetermined degree of polymerization, and the polymer having a predetermined degree of polymerization is discharged to form chips. Can be obtained by

Here, the content of SIPM with respect to the acid component is preferably in the range of 1.0 to 3.0 mol%. Filtration Within this range, the dyeability with a cationic dye is excellent, and the spinning operability such as increase in filtration pressure and yarn breakage is also favorable, which is preferable.

The intrinsic viscosity of the above component A is such that the ratio of the maximum value [η] max and the minimum value [η] min of the intrinsic viscosity is 1.0 ≦.
It is important that [η] max / [η] min ≦ 1.02. When [η] max / [η] min deviates from the above range,
Poor operability, such as frequent yarn breakage during melt spinning and poor spin filterability resulting in shortened spinneret life.

The polyester chips of the component A and the component B obtained as described above can be dried by an ordinary method and then subjected to ordinary melt spinning using a composite spinning apparatus.

The spinning method is not particularly limited. For example, a so-called conventional method in which an undrawn yarn is wound at a low speed and then drawn in a twisting process, a direct spinning drawing method (spin draw method), and a high-speed winding method. POY for obtaining partially undrawn yarn
The law is adopted.

Particularly, it is preferable to adopt the spin draw method and the POY method which are labor-saving and can be manufactured at low cost.

In the composite fiber of the present invention, the component A
The composite ratio, arrangement, and cross-sectional shape of the component B are not particularly limited, but for ultrafine fibers, the single yarn of the component A after alkali reduction treatment is preferably 0.33 decitex or less. Further, when the component A constitutes a hollow fiber after the alkali weight reduction treatment, it is necessary that one end of the easily soluble component in alkaline water B appears on the outer circumference of the fiber.

[0030]

EFFECT OF THE INVENTION The conjugate fiber of the present invention is produced with stable operability irrespective of the spinning method, and is woven and knitted without problems such as white powder generation and yarn breakage in the post-process such as false twisting. Since ultrafine fibers or hollow fibers can be efficiently obtained by alkali reduction treatment, they can be efficiently and stably used in suede-like woven or knitted fabrics with water absorption.

[0031]

The present invention will be described in more detail with reference to the following examples. The characteristic values in the following examples are measured by the following methods.

(1) Intrinsic Viscosity [η] A sample for measuring the intrinsic viscosity [η] of the polymerized chips was taken as follows. For polymer chips produced by the continuous polymerization method, the chips are sampled at appropriate time intervals and used as samples. The polymers produced by the batch polymerization method are chips that start and end immediately after each batch of polymer extrusion. , And chips were taken during the extrusion and used as a sample. The sample was measured by a Ubbelohde method at 20 ° C. in a mixed solvent of phenol / tetrachloroethane = 6/4 (weight ratio). The number of samples was 5, and the maximum intrinsic viscosity among the 5 samples was [η] max.
Then, the minimum intrinsic viscosity was taken as [η] min, and [η] max / [η] min was calculated from the respective measurement results and used as an index of the intrinsic viscosity unevenness of the polymer.

(2) Spinnability: Using the modified polyester and regular polyester,
The ultrafine splitting type conjugate fiber was spun by the so-called POY method or direct spinning drawing method (hereinafter referred to as SPD method), and evaluated from the degree of increase in spinning filtration pressure and the number of yarn breaks by ◯, Δ, and x.

(3) Heat resistance The above ultrafine splitting type composite fiber was subjected to false twisting with a spindle type false twisting machine, and the heater temperature during false twisting in which fluff, white powder, etc. were generated was shown. Here, the higher the heater temperature at the time of false twisting when fluff and white powder start to be generated, the better the false twisting heat resistance.

Example 1 Terephthalic acid, ethylene glycol, and SIPE (2.3 mol% in the acid component) were charged into a slurry tank, and trimethyl phosphate (45 ppm) and sodium acetate.3 were added thereto.
The hydrate was added to the polymer in an amount of 600 ppm to adjust the slurry pH to 5.2, and then the slurry was continuously supplied to the first esterification tank to carry out a pressure reaction at 270 ° C. and 68.6 kPa to give the second ester. 10 wt% of polyethylene glycol having an average molecular weight of 8000 and Irganox 245 (manufactured by Ciba-Geigy Co., Ltd.) which is a hindered phenol antioxidant are continuously supplied to the oligomerization tank.
% By weight, 400 ppm of antimony trioxide dissolved in ethylene glycol was added, the esterification reaction was carried out under normal pressure with the molar ratio in the second esterification tank being 1.14, and then continuously the initial polymerization tank and the latter polymerization tank. The solution was sent to and the polymerization reaction was continuously carried out at a reaction temperature of 280 ° C. to obtain a polyester of the component B easily soluble in alkaline water. The ratio of the maximum value to the minimum value of the intrinsic viscosity of the polyester of the component B easily soluble in alkaline water was 1.005.

Furthermore, polyethylene terephthalate having an intrinsic viscosity [η] = 0.630 and a titanium dioxide content of 0.4% by weight was used as a component A, and each was dried and then introduced into a composite spinning machine. After melted at a volume ratio of component A and component B of 3: 1 and extruded from the spinneret and after applying an oil agent by the usual method, the cross-sectional shape of 128 decitex / 25 filaments was wound by a goded roller with a peripheral speed of 3200 m / min. So-called POY yarns (Fig. 2) were obtained. The spinning operability was good, there were no problems such as yarn breakage and increase in pack pressure, and even when false twisting was carried out using this composite fiber, the false twisting operability was good, unlike the regular polyester. Furthermore, the quality of the satin woven fabric using the false twisted yarn was good.

Example 2 As Component A, 128 decitex / 25 filaments were prepared in the same manner as in Example 1 except that polyethylene terephthalate having an intrinsic viscosity [η] = 0.637 and a titanium dioxide content of 1.4% by weight was used. I got a POY yarn. Spinnability,
The false twist operability was as shown in Table 1.

Example 3 The polyesters of component A and component B used in Example 1 were melted at a volume ratio of component A and component B of 7: 3,
Extrusion from the spinneret After applying the oil agent by the usual method, the peripheral speed is 3
A POY yarn having a cross-sectional shape of 128 decitex / 48 filaments (FIG. 3) was obtained by winding with a goded roller at 200 m / min. The spinning operability and false twisting operability are as described in (Table 1).

Example 4 Polyesters of component A and component B used in Example 1 were melted at a volume ratio of component A and component B of 3: 1 and melted.
Extrusion from the spinneret After applying the oil agent by the usual method, the peripheral speed is 1
56 decitex with a cross-sectional shape (Fig. 2) stretched between a heated goded roller 1 at 300 m / min at 85 ° C and a heated goded roller 2 at 130 ° C at a peripheral speed of 3800 m / min.
A directly spun drawn yarn (SPD yarn) of 25 filaments was obtained. The spinning operability and false twisting operability are as described in (Table 1).

Example 5 The polyesters of component A and component B used in Example 1 were used and melted at a volume ratio of component A and component B of 2: 1.
Extrusion from the spinneret After applying the oil agent by the usual method, the peripheral speed is 3
A POY yarn having a cross-sectional shape of 84 decitex / 24 filament wound by a goded roller at 200 m / min (FIG. 4) and becoming a hollow fiber after alkali reduction treatment was obtained. The spinning operability and false twisting operability are as described in (Table 1).

Example 6 Terephthalic acid, ethylene glycol, and SIPM (1.5 mol% in the acid component) were charged into a slurry tank, and trimethyl phosphate (45 ppm) and sodium acetate.3 were added thereto.
The hydrate was added to the polymer in an amount of 700 ppm to adjust the slurry pH to 5.2, and then the slurry was continuously supplied to the first esterification tank to carry out a pressure reaction at 270 ° C. and 68.6 kPa to give the second ester. 400 p of antimony trioxide dissolved in ethylene glycol is continuously supplied to the chemical tank.
pm was added, the esterification reaction was carried out under normal pressure with the molar ratio in the second esterification tank being 1.14, and then continuously fed to the initial polymerization tank and the latter polymerization tank at a reaction temperature of 280 ° C. Then, a polymerization reaction was carried out to obtain a component A polyester. The ratio of the maximum value and the minimum value of the intrinsic viscosity of the component A polyester was 1.004.

Using the polyester of the component A and the polyester of the component B easily soluble in alkaline water as in Example 1, the component A is used.
After melted at a volume ratio of 3: 1 and the component B, extruded from the spinneret and applied with an oil agent by a usual method, the peripheral speed is 3200 m /
Winding with a minute goded roller 128 decitex /
A POY yarn having a cross-sectional shape of 25 filaments (Fig. 2) was obtained. The spinning operability and false twisting operability are as described in (Table 1). The composite fiber was dyeable with a cationic dye, and the cationic dyeability was good and the quality was good.

Comparative Example 1 The same method as in Example 1 was used except that the component B used was a readily soluble alkaline water-soluble polyester obtained by a batch polymerization method in which the ratio of the maximum value to the minimum value of the intrinsic viscosity was 1.03. The composite fiber was spun. The increase in filtration pressure during spinning was faster than in Example 1, and many yarn breakages occurred in spinning, resulting in poor operability. Furthermore,
When false twisting was performed using the POY yarn, white powder was generated, which was a problem.

Comparative Example 2 A composite fiber was spun in the same manner as in Example 1 except that the component A used was a polyester having a ratio of the maximum value and the minimum value of the intrinsic viscosity of 1.025. When the obtained POY yarn was subjected to false twisting, there was no problem such as white powder generation, but the spinning operability was very poor.

Comparative Example 3 Component A was a cationic dyeable polyester having a ratio of the maximum and minimum values of the intrinsic viscosity of 1.04, which was obtained by a batch polymerization method, and the content of the acid component of SIPM was 1.5 mol%. The conjugate fiber was spun in the same manner as in Example 6 except that it was used. The filtration pressure during spinning increased to the upper limit in 2 days, and many yarn breakages occurred, resulting in very poor spinning operability.

Comparative Example 4 Component A was obtained by a direct continuous polymerization method in which the content of the acid component of SIPM was 3.5 mol% and the ratio of the maximum value to the minimum value of the intrinsic viscosity was 1.015. The conjugate fiber was spun in the same manner as in Example 6 except that the cationic dyeable polyester was used. The filtration pressure during spinning rose sharply and the spinning operability was poor.

[0047]

[Table 1]

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a process for producing a polyester used in the present invention.

FIG. 2 is a cross-sectional view of an ultrafine splittable conjugate fiber of the present invention.

FIG. 3 is a cross-sectional view of an ultrafine splittable conjugate fiber of the present invention.

FIG. 4 is a cross-sectional view of the hollow composite fiber of the present invention.

[Explanation of symbols] 1 Slurry tank 2 First esterification tank 3 Second esterification tank 4 polymerization tank a, b, c modifier injection port 5 Alkaline water easily soluble component B 6 Component A remaining after alkali weight loss treatment

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Claims (2)

[Claims] 1. A composite fiber using two components having different alkali weight loss rates, wherein component A is 90% or more of ethylene terephthalate, and has a maximum intrinsic viscosity [η] max and a minimum intrinsic viscosity [η] min. Ratio of 1.0 ≦ [η] max / [η] mi
Using the polyester obtained by the direct continuous polymerization method satisfying n ≦ 1.02, the ratio of the maximum value [η] max and the minimum value [η] min of the intrinsic viscosity is 1.0 ≦ [η] as the component B. ma
A method for producing a polyester conjugate fiber, which comprises using an alkali water readily soluble polyester obtained by a direct continuous polymerization method satisfying x / [η] min ≦ 1.02. 2. Component A is obtained by a direct continuous polymerization method containing a metal sulfonate group-containing isophthalic acid component in an amount of 1.0 to 3.0 mol%, and has a maximum intrinsic viscosity [η] max and a minimum intrinsic viscosity [η]. ] Min ratio is 1.0 ≦ [η] max / [η] min
The method for producing a polyester conjugate fiber according to claim 1, which is a cationic dyeable polyester satisfying ≦ 1.02.