JPH08260344A - Fibrillated polyester fiber and its production - Google Patents

Abstract

PURPOSE: To stably obtain at a low cost, the subject fiber with soft touch free from sliminess thereon, having excellent touch feeling. CONSTITUTION: The fibrillated polyester fiber, which has curved flat section <=5μm in shorter side length and axially oriented continuous striae at intervals of 0.1-5μm throughout the fiber surface and lies at least partly split at the striae into ultrafine fibers each <=5μm in diameter, is obtained by the following process: a polyester containing 0.5-5wt.% of an organosulfonic acid metal salt of formula R-SO3 M is spun via a spinneret with the orifice of curved slit, cooled once to a temperature at or below the glass transition point of the polyester, and then allowed to travel through a hot zone at temperatures at or higher than the glass transition point but lower than the melting point, and wound up at a speed of 3500-6000m/min, and the resultant fiber is subjected to dry heat treatment at >=120 deg.C for >=10 s and then put to caustic reduction treatment >=10wt.% in reduction rate.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a fibrillated 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, and 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, a fiber having a spiral-shaped fiber cross section is proposed in JP-A-54-96118 as an improvement of the bulkiness of the polyester fiber, and the improved bulkiness is proposed. The polyester fiber of the fiber cross section is
Requires high-speed spinning conditions, lacks stability in the spinning process,
The physical properties of the obtained fiber are also high in residual elongation, and are not satisfactory in texture.

Further, in order to improve the water absorption and sweat absorption properties of polyester fibers, which are inferior to natural fibers such as cotton, silk and wool, and semi-synthetic fibers such as rayon and acetate, polyesters to which an organic sulfonic acid metal salt is added are used. A water-absorbent polyester fiber having fine pores in which hollow fibers are partly communicated with a hollow part by treating the hollow fibers with an alkaline aqueous solution is disclosed in JP-B-61-6018.
No. 8, Japanese Patent Publication No. 62-44065, etc., but it was not accompanied by improvement in texture.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fibrillated polyester fiber which is soft to the touch, has no slimy feel on the fiber surface, and has an excellent texture and is stable and at low cost.

[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 fiber having a curved flat fiber cross section with a short side length of 5 μm or less, which is made of polyester containing ethylene terephthalate as a main repeating unit in an amount of ˜5 wt%, and has a fiber surface of 0.1 to 5 μm. Fibrillated polyester fiber having continuous streak-shaped grooves oriented in the fiber axis direction at a groove interval of, and at least a part of the fibers is divided into ultrafine fibers having a diameter of 5 μm or less by the continuous streak-shaped grooves,

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 a polyester fiber is produced by melt spinning a polyester polymer, a spinneret having a curved slit is used as the orifice, and the yarn spun from the spinneret is once cooled to a temperature not higher than the glass transition point of the polyester, and then the glass. Run in a heating zone at a temperature above the transition point and below the melting point,
The fiber obtained by winding at a speed of 6000 m / min is 120
Dry heat treatment for 10 seconds or more at a temperature of ℃ or more, and a weight loss rate of 1
A method for producing a fibrillated polyester fiber is characterized in that an alkali reduction treatment of 0% by weight or more is performed.

The fibrillated polyester fiber of the present invention comprises a polyester having ethylene terephthalate as a main repeating unit containing 0.5 to 5% by weight of the organic sulfonic acid metal salt represented by the formula R-SO ₃ M. It 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%. ~ 4% by weight.

The fibrillated polyester fiber of the present invention is made of polyester containing an organic sulfonic acid metal salt, and as shown in FIG. 3, the fiber cross section has a short side length, that is, a flat thickness of 5 μm. A fiber having the following curved and flat fiber cross section, in which the entire surface of the fiber is 0.
It has continuous streak-shaped grooves oriented in the fiber axis direction at a groove interval of 1 to 5 μm, and all or part of the fibers have a continuous streak-shaped groove with a diameter of 5
It is divided into ultrafine fibers of not more than μm.

The production of the fibrillated polyester fiber of the present invention will be described below. As described above, the polyester polymer used is a polyester having ethylene terephthalate as a main repeating unit, and the addition of the organic sulfonic acid metal salt represented by the above formula R—SO ₃ M to the polyester is a melt spinning step of the polyester. May be added at any stage before the completion of, 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. Although it is good, it is preferable to use an addition means that allows sufficient mixing in the molten state after the addition.

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 added amount is less than 0.5% by weight, the formation of continuous streak-like grooves and the division into ultrafine fibers by the alkali reduction treatment in the subsequent step will be insufficient, and if it exceeds 5% by weight, the passability in the yarn making process will be improved. Becomes 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, the spinneret is
Using a spinneret with a curved slit whose orifice has a shape such as the spiral shape shown in FIG. 1a or the partially cutout ring shape shown in FIG. 1b, is spun from the spinneret under known arbitrary spinning conditions. To do.

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 a high speed does not generate yarn spots and the like 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.

The fiber of the yarn obtained by winding is A in FIG.
A fiber having a curved flat fiber cross section such as the spiral shape shown in FIG. 1 or the semi-ring shape shown in FIG. 1B.

In the present invention, the obtained fiber is false twisted if necessary, and then 120 ° C. or higher, preferably 14
Dry heat treatment is performed at a temperature of 0 ° C. or higher for 10 seconds or longer, preferably 20 seconds or longer. This dry heat treatment is necessary for the subsequent formation of continuous streak-like grooves by alkali reduction treatment and the formation of fibrous fibers that divide into ultrafine fibers. The dry heat treatment can be performed after weaving and knitting the obtained fibers into a fabric.

Further, in the present invention, after dry heat treatment,
Alkali weight loss treatment is applied. The alkali weight reduction treatment reduces the weight loss by 10% by weight or more, preferably 15% by weight or more, so that continuous streaky grooves oriented in the fiber axis direction with a groove interval of 0.1 to 5 μm are formed on the entire surface of the fiber. It is formed and at least a part of the fibers is divided into ultrafine fibers having a diameter of 5 μm or less by continuous streak grooves. In this alkali weight reduction treatment, the organic sulfonic acid metal salt contained in the fiber becomes an active point of alkali weight loss and causes 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.

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. A polyester with an intrinsic viscosity of 0.69 measured at 25 ° C. with a Uberrode viscometer using phenol / tetrachloroethane (50/50), which was added as a liquid, transferred to a polymerization tank, and subjected to polycondensation reaction at 285 ° C. under high vacuum. A polymer was obtained.

This polymer was made into chips by a conventional method and dried, and then, using a spinneret having 36 spiral curved slit orifices having an outer circumference of 2.9 mm and a slit width of 0.1 mm shown in FIG. 1a. , Spinning temperature 285 ℃
It was spun in. After the spun yarn is cooled and solidified with cooling air,
After traveling through a cylindrical indirect heat treatment device set at 210 ° C., then applying an oil agent, fluid entanglement treatment was performed by a fluid entanglement treatment device provided between the take-up rollers, and a heat treatment device set at 350 ° C. was set at an overfeed rate of 0. Winding at a winding speed of 4000 m / min.
A drawn fiber of 0 denier / 36 filament was obtained.

The obtained fiber had a strength of 4.1 g / d and a residual elongation of 26%, 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 33% by the alkali weight reduction treatment. As shown in FIG. 3, the fibers constituting the woven fabric after the weight reduction are fibers having a curved and flat fiber cross section, and fibers having continuous linear grooves oriented in the fiber axis direction with a groove interval of 0.3 to 3 μm. It has on the whole surface,
Moreover, a part of the fibers had a curved flat fiber cross section divided into ultrafine fibers having a diameter of 1 to 3 μm.

Comparative Example 1 A woven fabric was obtained in the same manner as in Example 1 except that the dry heat treatment before the alkali weight reduction treatment was not carried out. The fibers constituting the woven fabric after the weight reduction were Although continuous fiber-shaped grooves oriented in the fiber axis direction were formed on the entire surface of the fiber, division into ultrafine fibers and formation of fibrils were hardly observed.

[0033]

EFFECTS OF THE INVENTION The fibrillated polyester fiber of the present invention has an excellent texture because it is soft to the touch, has no slimy feel on the surface of the fiber, because at least a part of the fiber is divided into ultrafine fibers. The woven or knitted fabric made of the fibrillated polyester fiber of the present invention has a unique and excellent texture not found in the conventional woven and knitted polyester fiber. Further, according to the present invention, such a fibrillated polyester fiber can be obtained stably and at low cost.

[Brief description of drawings]

FIG. 1 is a plan view of an example of an orifice of a spinneret used in the present invention.

FIG. 2 is a fiber cross-sectional view of an example of a fiber after spinning and winding in the present invention.

3 is a scanning electron micrograph (magnification: 1000 times) of the fibrillated polyester fiber of the present invention according to Example 1. FIG.

[Explanation of symbols]

 a spiral curved slit orifice b partially cut ring curved curved slit orifice A spiral curved flat section fiber B semi-ring curved flat section fiber

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location D01F 6/62 303 D01F 6/62 303B 6/84 305 6/84 305A 6/86 301 6/86 301J 6/92 306 6/92 306A // D06M 101: 32

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). Of 0.5 to 5% by weight of ethylene terephthalate as a main repeating unit, the fiber having a curved flat fiber cross section with a short side length of 5 μm or less, and having 0 on the entire surface of the fiber. ．
It has continuous streak grooves oriented in the fiber axis direction at a groove interval of 1 to 5 μm, and at least a part of the fibers has a continuous streak groove with a diameter of 5
A fibrillated polyester fiber divided into ultrafine fibers of μm or less. 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 a polyester polymer containing ethylene terephthalate as a main repeating unit containing 0.5 to 5% by weight is melt-spun to produce a polyester fiber, a spinneret having a curved slit orifice is used,
After the yarn spun from the spinneret is once cooled to a temperature not higher than the glass transition point of polyester, it is run in a heating zone at a temperature not lower than the glass transition point and lower than the melting point to give 3500 to 60
A fibrillated polyester fiber characterized in that it is wound at a speed of 00 m / min, the obtained fiber is subjected to a dry heat treatment at a temperature of 120 ° C. or higher for 10 seconds or more, and further subjected to an alkali weight loss treatment of a weight loss rate of 10% by weight or more. Production method.