JPH08260343A - Hollow polyester fiber and its production - Google Patents

Abstract

PURPOSE: To stably produce a hollow polyester fiber having soft touch and excellent feeling free from slimy feeling of the fiber surface and exhibiting excellent water-absorption at a low production cost. CONSTITUTION: This hollow fiber is composed of a polyester having ethylene terephthalate as a main recurring unit and containing 0.5-5wt.% of an organic sulfonic acid metal salt expressed by formula R-SO3 M. The hollow polyester fiber can be produced from a hollow polyester fiber having a hollowness of >=25% and having continuous grooves formed along the fiber axis over the whole outer surface of the fiber and the inner surface of the hollow part interposing spaces of 0.1-5μm between the grooves by extruding a polyester through a hollow-spinning nozzle, temporarily cooling the extrudate at or below the glass transition point of the polyester, passing through a heating zone maintained at a temperature between the glass transition point and the melting point, winding up at a speed of 3,500-6, 000m/min and subjecting the obtained fiber to alkali- thinning treatment at a reduction ratio of >=10%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hollow polyester fiber and a method for producing the same.

[0002]

2. Description of the Related Art Polyester fibers have many excellent properties and are widely used for various purposes such as clothing. However, since the polyester fiber is produced by the melt spinning method, it generally has a smooth surface, a hard touch, and a unique slimy feel, which is a disadvantage in terms of texture. There is a fibrillar fiber as an improvement of such a defect. As a method for producing the fibrillar fiber, a method of blending polyester and an incompatible polymer with polyester and melt spinning (JP-A-55-16906, etc.) and polyester And polyamide are spun together and treated with a swelling agent for polyamide (Japanese Patent Publication No. 9427/1986)
Is proposed.

Further, polyester fibers have a functional defect that they are inferior in water absorbency and sweat absorbability as compared with natural fibers such as cotton, silk and wool, and semi-synthetic fibers such as rayon and acetate. In order to improve these drawbacks, a hollow fiber made of a polyester to which a metal salt of an organic sulfonic acid is added is treated with an alkaline aqueous solution, and a water-absorbing polyester fiber having fine pores partially communicating with a hollow portion is disclosed in Japanese Patent Publication No. 61-60188. It is proposed in the official gazette and Japanese Patent Publication No. 62-44065.

However, the conventional fibrillar fibers have an improved texture, but are inferior in water absorbency, and the conventional hollow fibers having a microporous fiber surface have an improved water absorbency, but have a texture. It was not accompanied by the improvement in terms of.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a stable and low-cost hollow polyester fiber having a soft touch, an excellent texture without a slimy feeling on the fiber surface, and an excellent water absorption. With the goal.

[0006]

The present invention provides the formula R--SO ₃
M (R: alkyl group having 3 to 30 carbon atoms or 7 to carbon atoms)
40 aryl group or alkylaryl group, M: alkali metal) represented by 0.5
A hollow fiber made of polyester containing ethylene terephthalate as a main repeating unit in an amount of up to 5% by weight, having a hollowness of 25% or more, and having an outer surface of the fiber surface and a hollow inner wall surface of 0.1 to 5 μm. Hollow polyester fiber having continuous streaky grooves oriented in the fiber axis direction at groove intervals,

And, the formula R-SO ₃ M (R: carbon number _{3 to 3} )
A main repeating unit is ethylene terephthalate containing 0.5 to 5% by weight of an organic sulfonic acid metal salt represented by an alkyl group of 0 or an aryl group or an alkylaryl group having 7 to 40 carbon atoms, M: alkali metal). When melt-spinning a polyester polymer to produce polyester fibers, the yarn spun from the hollow spinneret is once cooled to a temperature not higher than the glass transition point of polyester, and then a heating zone at a temperature not lower than the glass transition point and lower than the melting point. Run inside,
It is a method for producing hollow polyester fibers, which comprises winding the fibers at a speed of 3500 to 6000 m / min and subjecting the resulting fibers to alkali weight loss treatment with a weight loss rate of 10% or more.

The hollow polyester fiber of the present invention contains 0.5% of the organic sulfonic acid metal salt represented by the formula R-SO ₃ M.
It is composed of polyester containing ethylene terephthalate as a main repeating unit in an amount of up to 5% by weight. Polyester has terephthalic acid or an ester-forming derivative thereof as a dicarboxylic acid component and ethylene terephthalate having ethylene glycol or an ester-forming derivative as a glycol component as a main repeating unit. The part may be replaced with other dicarboxylic acid component and / or glycol component.

Other dicarboxylic acid components include, for example, isophthalic acid, 5-sulfoisophthalic alkali metal salt, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid, adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, etc. Dicarboxylic acid or its ester, p-oxybenzoic acid, p-β
An oxycarboxylic acid such as oxyethoxybenzoic acid or an ester thereof.

Other glycol components include, for example, alkylene glycols having 2 to 10 carbon atoms, 1,4-cyclohexanedimethanol, neopentyl glycol,
Examples include 1,4-bis (β-oxyethoxy) benzene, bisglycol ether of bisphenol A, and polyalkylene glycol.

Further, when the polyester is substantially linear, polycarboxylic acids such as trimellitic acid and pyromellitic acid, polyols such as pentaerythritol, trimethylolpropane and glycerin, monohydric polyalkylene oxide and phenylacetic acid. A polymerization inhibitor such as

The polyester may be one synthesized by any known method. For example, polyethylene terephthalate will be explained. Either terephthalic acid and ethylene glycol are directly esterified or dimethyl terephthalate and ethylene glycol are transesterified. By making a glycol ester of terephthalic acid or a low condensate thereof, and then polycondensing it, a known catalyst, antioxidant, coloring inhibitor, ether bond by-product inhibitor, flame retardant is used in the synthesis. Etc. may be added.

The above formula R-SO contained in the polyester
Examples of the organic sulfonic acid metal salt represented by ₃ M include sodium salt of alkylsulfonic acid having 3 to 30 carbon atoms,
Examples include potassium salt, lithium salt, toluenesulfonic acid, sodium salt of dodecylbenzenesulfonic acid, potassium salt, lithium salt, or a mixture of the same kind or different kinds thereof, and the polyester is 0.5 to 5% by weight, preferably 1%. The content of the organic sulfonic acid metal salt contributes to the improvement of the hydrophilicity of the polyester fiber.

The hollow polyester fiber of the present invention is made of polyester containing an organic sulfonic acid metal salt, and has a hollow ratio of 25% or more, which is the ratio of hollow portions in the fiber cross section. The entire inner wall surface has continuous streak grooves oriented in the fiber axis direction at groove intervals of 0.1 to 5 μm. If the hollow ratio is less than 25%, the water absorption is insufficient, and even if the groove interval is less than 0.1 μm or more than 5 μm, the softness to the touch is not imparted and the slimy feeling is not sufficiently eliminated. High hollowness in the hollow polyester fiber of the present invention, the water content of the fiber surface is taken into the fiber inside, the continuous streak groove of the outer surface of the fiber surface and the hollow inner wall surface softens the touch, improves the slimy feeling, and further the surface The water absorption is improved by the capillary phenomenon due to the fibrillation.

FIG. 1 shows a scanning electron micrograph of an example of the hollow polyester fiber of the present invention.

The production of the hollow polyester fiber of the present invention will be described below. The polyester polymer used is
As described above, the polyester having ethylene terephthalate as a main repeating unit is added to the polyester with the organic sulfonic acid metal salt represented by the formula R—SO ₃ M before the melt spinning process of the polyester is completed. It may be at any stage, for example, it may be added and blended in the raw material of the polyester, may be added during the synthesis of the polyester, or may be added before the melt spinning after the synthesis, but after addition It is preferable to use an addition means that allows sufficient mixing in the molten state.

The amount of the organic sulfonic acid metal salt added to the polyester is 0.5 to 5% by weight, preferably 1 to 4% by weight.
If the addition amount is less than 0.5% by weight, the hydrophilicity is not imparted and the continuous streak-like grooves are not sufficiently formed by the alkali weight reduction treatment in the subsequent step. Getting worse.

When adding the organic sulfonic acid metal salt,
The organic sulfonic acid metal salts that are usually commercially available contain impurities of inorganic salts such as sodium chloride and sodium sulfate, which impair the stability of melt spinning such as back pressure rise and yarn breakage. Therefore, it is desirable to reduce impurities in the organic sulfonic acid metal salt in advance, and it is preferable that sodium chloride contained in the organic sulfonic acid metal salt is less than 0.1%.
It is 5% by weight or less and sodium sulfate is 0.1% by weight or less.

In the melt spinning of a polyester polymer containing an organic sulfonic acid metal salt, as a spinneret,
A hollow spinneret for producing hollow fibers is used, and spinning is performed from the spinneret under any known spinning conditions. The hollow spinneret used may be a hollow spinneret for not only circular hollow fibers but also modified hollow fibers.

After spinning, the spun yarn is once cooled to a temperature below the glass transition point of polyester. This cooling is indispensable for making the obtained fiber excellent in dyeability and for making the physical properties of the fiber practically sufficient. After cooling, the yarn is subsequently reheated by running in a heating zone at a temperature of not less than the glass transition temperature and less than the melting point, preferably 120 to 130 ° C. When the temperature of the heating zone is lower than the glass transition point, the fiber physical properties cannot be practically used and are extremely inferior, and when the temperature is higher than the melting point, fusion between single fibers or yarn breakage is caused, which is a problem in yarn production. Not only that, but the texture of the fabric obtained by weaving and knitting the obtained fiber is remarkably inferior.

The device for forming the heating zone is preferably an indirect heating type device which does not come into contact with the yarn, because the yarn running at high speed does not cause yarn unevenness due to contact with the heating portion. Temperature unevenness due to the high-speed air flow associated with
In order to prevent a decrease in thermal efficiency, it is preferable that the device has an opening area of the yarn inlet / outlet portion as small as possible.

As a heating method in the heating zone, any method such as a method of preheating a gas such as air and supplying it into the apparatus, or a method of directly heating the atmosphere with a heater installed around the traveling yarns can be used. It may be. Further, the heating zone may be divided into two or more and are under different temperature atmospheres. The yarn running in the heating zone is heat-treated and substantially stretched.

The yarn passing through the heating zone is appropriately taken up by a take-up roller after applying an oil agent to the yarn,
Although it is wound by a winder, in the present invention, the winding is 3500 to 6000 m / min, preferably 4000 to
The speed is 6000 m / min. Winding speed is 3500m
If it is less than 1 / minute, the dyeability of the obtained fiber is poor, and the physical properties of the fiber are extremely inferior to practical use.
When it exceeds 00 m / min, the yarn cannot be sufficiently heat-treated and stretched in the heating zone. The take-up speed is preferably 0.5 to 1% higher than the take-up speed.

When winding the yarn through the take-up roller, it is preferable to provide a heat relaxation treatment device between the two take-up rollers, and to relax the stress of the yarn by heating under overfeed. Further, the relaxation rate of the yarn can be increased by providing a fluid entanglement treatment device before or after the thermal relaxation treatment device.

In the present invention, the obtained fiber is subjected to false twisting or heat treatment, if necessary, at any step,
Alkali weight reduction treatment is carried out. Prior to the alkali weight reduction treatment, at a temperature of 120 ° C. or higher, preferably 140 ° C. or higher, 1
Dry heat treatment is performed for 0 seconds or longer, preferably 20 seconds or longer. This dry heat treatment is necessary to form continuous streak-like grooves on the fiber surface and the hollow inner wall surface by a subsequent alkali weight reduction treatment and to form a fibble, and it is preferable that the dry heat treatment is performed after weaving and knitting the obtained fiber into a cloth. .

Further, in the present invention, after dry heat treatment,
Alkali weight loss treatment is applied. In the alkali weight reduction treatment, the weight reduction rate is 10% or more, preferably 15% or more. By this alkali weight reduction treatment, continuous streak-shaped grooves oriented in the fiber axis direction were formed on the entire surface of the fiber and the inner wall surface of the hollow at groove intervals of 0.1 to 5 μm, and further shown in a scanning electron microscope enlarged photograph of FIG. Thus, a microporous structure is formed inside the fiber.
In the alkali weight reduction treatment, the oriented organic sulfonic acid metal salt contained in the fiber serves as an alkali weight loss active site, which causes formation of continuous streaky grooves, a microporous structure and fibrillation.

In the alkali reduction treatment, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, sodium carbonate, potassium carbonate or the like is used as an alkali compound, and sodium hydroxide or potassium hydroxide is particularly preferably used. Depending on the type of alkaline compound, treatment conditions, etc., an alkaline compound aqueous solution having a concentration of 0.1 to 30% by weight is at room temperature to 100 ° C.
The processing temperature is 1 minute to 4 hours. This alkali reduction treatment is preferably performed after forming the cloth.

[0028]

EXAMPLES The present invention will be specifically described below with reference to examples. In the examples, parts and% mean parts by weight and% by weight. The characteristic values in the examples were measured by the following methods.

(Intrinsic viscosity) Phenol / tetrachloroethane (50/50) was used to measure at 25 ° C. with an Ubbelohde viscometer.

(Water Absorption Performance) The obtained raw yarn was subjected to the following conditions: warp: polyester normal yarn 50 denier / 18 filaments weft: hollow polyester fiber yarn 100 denier of the present invention /
30 filaments Warp density: 40 filaments / cm Weft density: 29.1 filaments / cm After weaving, scouring, presetting, and alkali weight reduction treatment at a boiling temperature for a predetermined time using a 2% aqueous solution of sodium hydroxide. This woven fabric was used as a sample and attached to a circular frame for embroidery with a diameter of 15 cm, and the disappearance time of the water drops dropped by the water drop dropping method was measured. Distilled water is used for the water drop, and the water drop amount is 0.039.
ml, the distance between the tip of the burette and the sample surface is 1 cm,
The average water droplet disappearance time was measured at room temperature and a relative humidity of 55 to 60% and 5 to 7 times.

Example 1 100 parts of terephthalic acid and 52 parts of ethylene glycol were charged into an esterification tank and 4 kg.
The esterification reaction was performed at 260 ° C. under a pressure of / cm ² . Subsequently, the obtained reaction product contained 0.01% trimethyl phosphate (polymer to be produced), 0.04% antimony trioxide (polymer to be produced), and titanium dioxide 0.5.
% (Pair-forming polymer) as an ethylene glycol dispersion, and 2.0% of sodium alkylsulfonate having an average carbon number of 15 (containing 0.02% of sodium chloride and 0.05% of sodium sulfate) is dispersed in ethylene glycol. It was added as a liquid, transferred to a polymerization tank, and subjected to polycondensation reaction at 285 ° C. under high vacuum to obtain a polyester polymer having an intrinsic viscosity of 0.69.

The polymer was made into chips by a conventional method, dried, and then spun at a spinning temperature of 284 ° C. using a circular hollow spinneret having 30 holes. After the spun yarn is cooled and solidified with cooling air, it is run in a cylindrical indirect heat treatment device set at 210 ° C., then an oil agent is applied, and fluid entanglement treatment is performed by a fluid entanglement treatment device provided between the take-up rollers. , 35
Overheat rate of heat treatment equipment set at 0 ℃ is 0.5
% Of denier / 36 filaments to obtain a drawn fiber of 100 denier / 36 filaments.

The obtained fiber had a strength of 3.8 g / d and a residual elongation of 34% and was homogeneous without dyeing stains when dyed. After weaving using the obtained fiber, the woven fabric was dry heat treated at 180 ° C. for 1 minute, and subsequently, the weight reduction rate was reduced to 31% by the alkali weight reduction treatment. The fibers constituting the woven fabric after weight reduction are hollow fibers having a hollow ratio of 36%, and continuous streak-shaped grooves oriented in the fiber axis direction with a groove interval of 0.3 to 3 μm are formed on the entire surface of the fiber surface and the hollow inner wall surface. I had it. The obtained woven fabric had an excellent soft and dry texture, and had good water absorption performance with a water drop disappearance time of 2 minutes and 37 seconds.

Comparative Example 1 A woven fabric was obtained in the same manner as in Example 1 except that the polyester polymer to which sodium alkyl sulfonate was not added was used, but the hollow fiber constituting the woven fabric after weight loss was obtained. No continuous streak-like grooves were formed on the entire surface of the fiber and the inner wall surface of the hollow, the hollow ratio was as low as 17%, and the water drop disappearance time was 45 minutes 29 seconds, which was poor in water absorption performance. there were.

[0035]

EFFECTS OF THE INVENTION The hollow polyester fiber of the present invention has a high hollow ratio and continuous streak-like grooves on the fiber surface and the hollow inner wall surface, and the microporous structure inside the fiber facilitates fibrillation, resulting in a soft touch. The woven or knitted fabric made of the hollow polyester fiber of the present invention has excellent texture and water absorbency because it has an excellent texture without stickiness on the fiber surface and excellent water absorbency. Further, according to the present invention,
Such hollow polyester fibers can be obtained stably and at low cost.

[Brief description of drawings]

FIG. 1 is a scanning electron micrograph (magnification: 500 times) of an example of the hollow polyester fiber of the present invention.

FIG. 2 is a scanning electron microscope enlarged photograph (magnification: 1000 times) of an example of the hollow polyester fiber of the present invention.

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Claims (2)

[Claims] 1. An organic sulfonic acid metal salt represented by the formula R-SO ₃ M (R: an alkyl group having 3 to 30 carbon atoms or an aryl group or an alkylaryl group having 7 to 40 carbon atoms, M: an alkali metal). A hollow fiber made of polyester containing ethylene terephthalate as a main repeating unit, which contains 0.5 to 5% by weight, and has a hollowness of 25% or more, and has a hollow ratio of 0. 1
Hollow polyester fiber having continuous streaky grooves oriented in the fiber axis direction with a groove interval of ˜5 μm. 2. An organic sulfonic acid metal salt represented by the formula R—SO ₃ M (R: an alkyl group having 3 to 30 carbon atoms or an aryl group or an alkylaryl group having 7 to 40 carbon atoms, M: an alkali metal). When melt-spinning a polyester polymer containing 0.5 to 5% by weight of ethylene terephthalate as a main repeating unit to produce a polyester fiber, a yarn spun from a hollow spinneret has a glass transition point not higher than the glass transition point of the polyester. After cooling once to a temperature, it is run in a heating zone at a temperature above the glass transition point and below the melting point,
A method for producing a hollow polyester fiber, which comprises winding the fiber at a speed of 00 to 6000 m / min, and subjecting the obtained fiber to an alkali weight loss treatment with a weight loss rate of 10% or more.