JPH05302267A - Hollow fiber and its production - Google Patents

Abstract

PURPOSE:To obtain hollow fiber, having an especially high percentage of hollowness, a low ratio of wall thickness of the hollow fiber, slits in the longitudinal direction of the fiber and especially better in heat insulating properties and reduction in weight than those of conventional products of the same material when formed into fabric. CONSTITUTION:The objective hollow fiber has slits, communicating with the hollow part and the outside on the fiber surface and formed continuously in the fiber axial direction and an average thickness of the hollow fiber of 0.025-0.225 based on the round equivalent diameter and the objective method for producing the fiber is provided. A material, unconventionally good in heat insulating properties and capable of reducing the weight can be provided by realizing a high percentage of hollowness. Furthermore, since a space in the fiber communicates through the fine slits with the open air, a material capable of improving the water absorbency can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material having a good heat-retaining property and capable of being quantified, and more specifically to a fiber having a high hollow ratio which cannot be obtained by a usual spinning method. Is.

[0002]

2. Description of the Related Art Conventionally, hollow fibers have been used to improve the heat retaining property of fabrics or to achieve weighting.

The improvement of heat retention and the quantification by hollowing are more effective as the hollowness is higher. When a hollow fiber is obtained by a melt-spinning method, spinning is conventionally performed by using a spinneret having a shape as shown in FIG. 5, but in this method, the hollow fiber is about 20% at most, but from the viewpoint of operability. This is a practical limit, and there are problems such as destabilization of the spinning state and generation of hollow group between single yarns even if an attempt is made to achieve a hollow rate of more than 30%.

Further, the hollow fiber produced by the conventional method has a drawback that the hollow ratio is reduced due to the flattening of the hollow shape, which occurs during heat setting in the drawing false twisting process, especially when the hollow ratio is high. ..

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks of hollow fibers, that is, the difficulty of achieving a high hollow ratio of 30% or more, enables easy fiber production, is excellent in heat retention and is also water absorbent. The purpose of the present invention is to provide a fiber material that is expensive and can be made lightweight.

[0006]

[Means for Solving the Problems] Means for solving the above-mentioned problems, that is, the present invention is a hollow fiber in which a continuous hollow portion exists in the fiber axial direction, and the hollow portion is formed on the fiber surface. And the slits communicating with the outside atmosphere form a sleeve shape in which the slits are continuous in the fiber axis direction, and the average thickness of the hollow fibers is 0.0
Hollow fiber characterized by being 25 to 0.225 times,
And in the complex spinning of the elution component (A) and the residual component (B) which has no elution property to the solvent of the elution component (A) or has a sufficiently slow dissolution rate than the elution component (A),
The cross section of the obtained conjugate fiber is formed so that the outer periphery of the eluted component (A) is surrounded by the residual component (B), and the cross sectional area of the eluted component (A) is 30 to 9 with respect to the cross sectional area of the conjugate yarn fiber.
In the range of 0%, and a part of the eluted component (A) is formed into a shape in which the residual component (B) is communicated with the outer peripheral portion of the fiber by melt-spinning using a spinneret device, and then drawing. A method for producing a hollow fiber, which comprises subjecting an elution component (A) to an elution treatment.

The hollow fiber of the present invention has a sleeve-shaped cross section, and has a hollow ratio unmatchedly higher than that of a conventional hollow fiber obtained by melt spinning. However, the hollow ratio mentioned here is a value calculated by converting into a perfect circle. The hollow fiber of the present invention does not necessarily have a circular cross section, and thus may be flattened.

The sleeve-shaped hollow fiber of the present invention comprises a hollow portion continuous in the fiber axis direction and a slit connecting the hollow portion and the external atmosphere. This slit is
It may be closed. It needs to be unbonded. It is necessary that the average thickness of the hollow fiber is 0.025 to 0.255 which is the diameter of the hollow fiber corresponding to the true circle. However, the diameter equivalent to a perfect circle referred to in the present invention means the diameter when the perimeter of the outer circumference of the fiber cross section is replaced with a perfect circle.

When the upper limit of this range is exceeded, the hollow ratio becomes less than 30%, and the difference from the conventional hollow fiber becomes small. On the other hand, if it is below the lower limit of this range, the wall thickness becomes too thin, and the shape retention becomes poor even if a polymer having a considerably high rigidity is used.

The hollow fiber of the present invention can be produced by preferentially eluting and removing one component of the composite fiber obtained by composite spinning of two kinds of polymers. The combination must be such that only one of the components, that is, the eluting component resin, can be selectively eluted with the solvent. If the solvent used is an alkaline aqueous solution,
A polyester polymer can be used as the elution component, and when an organic acid such as formic acid or an organic solvent such as chloroform is used as the solvent, polyamide, polystyrene or the like can be used as the elution component.

The combination of the elution component (A) and the residual component (B) is either completely insoluble in the solvent of the elution component or the resin having a sufficiently slow elution rate must be used as the residual component. If it is an alkaline aqueous solution, a combination of polyamide / polyester can be easily used, but even in this case, in order to increase the elution rate of the polyester as the elution component, the modified polyester or polyester is added with a water-soluble component such as polyalkylene glycol. It is more preferable to use an easily-eluting polymer such as a melt-blended polymer because the elution treatment time is significantly shortened.

As described above, the solvent used in the present invention may have no solubility in the solvent or may have a residual component resin whose dissolution rate is sufficiently slower than that of the eluting component resin. Although an aqueous solution and various organic acids and organic solvents can be used, it is particularly preferable to use an alkaline solution which can be used in the current general post-treatment because it is advantageous in terms of treatment cost and equipment. Even when polyester is used as the residual component, the eluted component is a modified polyester such as an easily-elutable polyester or a water-soluble polyester such as a polyester blended with polyalkylene glycol, and an alkaline aqueous solution is used as a solvent to remove the eluted component. It can be selectively eluted.

The polymers which can be used in the present invention are
For example, as the residual component, nylon 6, nylon 66,
Amorphous polyamide consisting of isophthalic acid / terephthalic acid / hexamethylenediamine, polyethylene terephthalate, polybutylene terephthalate, polyethylene, polyetherimide, polyphenylene sulfide,
Polyether ether ketone, etc., and modified polymers of these polymers can be used. The elution component may be selected so that the difference in elution rate may be sufficient depending on the respective residual components. For example, polyester, nylon 6, polystyrene, etc. are suitable. Polyethylene terephthalate blended with polyethylene glycol is most suitable because the elution rate is extremely high.

The slit formed on the fiber surface in the present invention is a path through which the eluted component dissolves out of the fiber when the eluted component elutes, and after elution, connects the hollow portion inside the fiber and the outside air outside the fiber. On the road. For this reason, in order to shorten the elution step or to completely remove the elution components, it is preferable that the slit width is large, but for heat retention, which is one of the objects of the present invention, the slit should be as thin as possible. Good.
That is, in order to maximize heat retention, it is necessary to suppress the movement of air between the hollow portion inside the fiber and the outside air, and the width of the slit portion is preferably 20% or less of the outer circumference of the fiber cross section, Further, when it is 1 μm or less, water absorption and hygroscopicity are expressed by the expression of capillary phenomenon, which is particularly preferable. Further, in order to make the slit thin, it is necessary that the elution rate of the elution component is extremely higher than that of the residual component, and in this respect also, how to combine the residual component with the elution component and the solvent is important.

In the method for producing the fiber of the present invention, there is no elution property with respect to the eluting component (A) and the solvent of the eluting component (A), or the residual component (having a sufficiently slow dissolution rate than the eluting component (A) ( Composite spinning is performed using the two polymers of B).

The above-mentioned two kinds of polymers, which are separately melt-measured, are led to the composite portion of the composite spinneret apparatus shown in FIG. 1A, and the polymer A having the higher solubility is extruded through the discharge holes 2 and 2 '. A polymer B having a low solubility, which is a residual component, is extruded from the slit 1 and compounded in the nozzle introduction hole 3.

FIG. 2 is a sectional view taken along the line EE 'in FIG. Dissolved component polymer A is extruded through holes 2 and 2 ',
Polymer B, which has low solubility of residual components, has 8 slits 1
Since it is further pushed out, the composite form shown in FIG. 4 is formed in the nozzle introduction hole 3.

When extruded from a conventional round hole orifice, FIG.
The composite fiber shown in Fig. 3 is obtained, and the hollow composite fiber shown in Fig. 3 is obtained by extruding from the two semicircular slits shown in Fig. 1B.

The fiber to be obtained is intended to obtain a high-level hollow fiber by eluting a polymer that is easily eluted after the fiber is formed. From the viewpoint of productivity and economy, the hollow fiber shown in FIG. 3 is preferable. ..

The spinning temperature at this time is preferably 15 to 25 ° C. higher than the melting point of the polymer having the highest melting point among the polymers to be composited, but it is particularly preferable to set it to the melting point + 15 ° C. to increase the hollow ratio. preferable. In this case, the composite ratio of the dissolved component polymer and the residual component polymer is appropriately adjusted in relation to the hollowness of the obtained fiber.

The extruded composite fiber is taken up by a godet roller while being cooled by cooling air. The take-up speed at this time is not particularly limited, but it is economically preferable to take it off at 600 to 4000 m / min. The taken-up yarn may be once wound and drawn by a drawing machine in a separate step, or may be drawn by a godet roller on a spinning machine and then drawn by second and third godet rollers. ..
The stretching temperature at this time may be set so that the substantial yarn temperature becomes the glass conversion temperature of the polymer. After making the obtained drawn yarn into a yarn or a cloth, a highly soluble polymer that forms part of the inside and the outside of the fiber is eluted with a soluble solvent to obtain an unprecedented high hollow fiber. Be done.

Further, in the conjugate fiber used for producing the hollow fiber of the present invention, a crimped yarn can be obtained by eccentricizing the eluted component as shown in FIG. With this method, it is possible to further improve the heat retention property and increase the weight saving by increasing the bulkiness due to the appearance of crimps.

[0023]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 Phenol / tetrachloroethane = 3 as an elution component
96% as a residual component based on 100 parts of polyethylene terephthalate having an intrinsic viscosity of 0.63 in a 1/2 mixed solvent.
Using 100 parts of nylon 6 having a relative viscosity of 2.60 in concentrated sulfuric acid, spinning was performed at a spinning temperature of 270 ° C. and a spinning speed of 1300 m / min using the spinneret device shown in FIG. The yarn was drawn at a hot roller temperature of 60 ° C. and a draw ratio of 2.70.

A tube knitting was performed using the obtained drawn yarn, and a weight reduction treatment was performed in a 5.0 wt% NaOH aqueous solution at 90 ° C. for 50 minutes. The hollow ratio was 45 with a cross section shown in FIG. %, And the average wall thickness was 0.25 of the fiber diameter, a hollow fiber was obtained.

Example 2 Phenol / tetrachloroethane = 3 as an elution component
As a residual component, 100 parts of polyethylene terephthalate having an intrinsic viscosity of 0.63 in a 1/2 mixed solvent and 10 parts of polyethylene glycol having an average molecular weight of 20000 were melt-kneaded to obtain 100 parts of a blended polymer,
40% nylon 6 with a relative viscosity of 2.60 in 6% concentrated sulfuric acid
7-B was spun at a spinning temperature of 270 ° C. and a spinning speed of 1300 m / min, and the obtained undrawn yarn was drawn at a hot roller temperature of 70 ° C. and a draw ratio of 2075.

Using this drawn yarn, the warp density of a single yarn is 13
Weaved into a lawn with 0 yarns / in and weft density of 110 yarns / in. This loan (plain weave) is 90 ℃, 5.0wt% NaO
When the weight reduction treatment was performed for 30 minutes in the H aqueous solution, the thickness of the woven fabric was not changed, and the weight was reduced by 70%, and a high degree of weight reduction was achieved.

At this time, the fibers forming the lawn have completely removed the eluted components, and have a hollow ratio of about 65% having a cross section shown in FIG. 8B and a wall thickness of 0.20 of the fiber diameter.
It was a hollow fiber. Further, the woven fabric thus obtained had a softer texture and was remarkably excellent in heat retention and hygroscopicity.

[0029] Example _{3 HO- (C 2 H 4 O} ) m -C 3 H 6 -O- (C 2 H 4 O) n -H ···· (1) ( provided that, m + n = 6) elution component Is 3% by weight of the compound represented by the above formula (1) with respect to ethylene glycol, and 3 mol% of dimethyl 5-sodium sulfoisophthalate with respect to the terephthalic acid component.
10 wt% of polyethylene glycol having an average molecular weight of about 20,000 was added to the copolymerized modified polyethylene terephthalate.
% 100 parts of the melt-blended modified polyester is used, and the residual component is phenol / tetrachloroethane =
Using 60 parts of polyethylene terephthalate having an intrinsic viscosity of 0.63 in a 3/2 mixed solvent, a spinning temperature of 280 ° C. and a spinning speed of 1300 m / using a spinneret device shown in FIG.
The unstretched yarn obtained by spinning at min was drawn at a hot roller temperature of 80 ° C. and a draw ratio of 3.0.

Using this drawn yarn, a lawn was woven in the same manner as in Example 2 and then weight-reduced for 30 minutes in a 5.0 wt% NaOH aqueous solution at 90 ° C.
%, And we were able to achieve advanced weight reduction. At this time, the eluted components of the fibers forming the lawn are completely eluted and removed, and the hollow ratio with the cross section shown in FIG.
%, And the wall thickness was a hollow fiber having a fiber diameter of 0.20. Further, the woven fabric thus obtained had a softer texture and was remarkably excellent in heat retention and hygroscopicity.

Example 4 Using a spinneret capable of obtaining an eccentric composite yarn having a cross-sectional shape shown in FIG. 9, spinning and drawing were carried out in the same manner as in Example 2 to obtain a lawn. The resulting woven fabric was bulky and had a soft touch because the constituent fibers had crimpability. After scouring this woven cloth, preset (120 ° C, 30
After that, the weight reduction treatment was performed in the same manner as in Example 2 and the final set (140 ° C., 30 seconds) was performed. As a result, improvement in heat retention and weight reduction could be achieved in comparison with Example 2.

Comparative Example 1 Polyethylene terephthalate having an intrinsic viscosity of 0.75 in a mixed solvent of phenol / tetrachloroethane = 3/2 was used, and the spinning temperature was 275 ° C. using the spinneret shown in FIG.
Spinning was performed at a spinning speed of 1300 m / min to obtain a hollow fiber having a hollow ratio of 20%. However, the obtained hollow fiber has heat retention as compared with the present invention. The lightweight property was insufficient, and the hygroscopicity was no different from that of conventional polyester.

Comparative Example 2 Polyethylene terephthalate 50 in Example 1
And 100 parts of nylon 6 were used to obtain a hollow fiber having a hollow ratio of 25%. However, the obtained hollow fibers showed almost no difference in heat retention and lightness as compared with the conventional hollow fibers.

[0034]

According to the present invention, the following outstanding effects can be obtained. (1) By realizing a high hollow ratio, it is possible to provide a material which has a good heat retaining property and which can be reduced in weight, which has never been obtained. (2) Since the air inside the fiber and the outside air communicate with each other through fine slits, it is possible to provide a material that improves water absorption.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a composite spinneret device used for production of the present invention.

FIG. 2 is a view showing a cross section taken along the line EE ′ of FIG.

FIG. 3 is a view showing a cross section of a hollow composite fiber obtained by carrying out the present invention.

FIG. 4 is a view showing a cross section of a conjugate fiber obtained by carrying out the present invention.

FIG. 5 is a schematic view of a conventional spinning nozzle for producing a hollow fiber.

FIG. 6 is a schematic view of a spinneret device used in the production of the present invention.

FIG. 7 is a schematic view of a spinneret device other than that shown in FIG. 6 used in the production of the present invention.

FIG. 8 is a view showing a cross section of the fiber of the present invention.

FIG. 9 is a view showing a cross section of the fiber of the present invention, and is a view showing a cross section of a composite yarn of a residual component and an eluted component.

[Explanation of symbols]

1 is a slit, 2 and 2'is a discharge hole, 3 is a nozzle introduction hole,
4 is an elution component and 5 is a residual component.

Continuation of front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location D01F 6/62 303 E 7199-3B 8/14 B 7199-3B C 7199-3B D06M 13/07

Claims (2)

[Claims] 1. A hollow fiber having a hollow portion continuous inside the fiber in the axial direction of the fiber, and having a sleeve shape in which a slit communicating with the hollow portion and the outside atmosphere is continuous on the fiber surface in the axial direction of the fiber. And the average thickness of the hollow fibers is 0.025 to 0.2 of the diameter corresponding to the true circle of the hollow fibers.
Hollow fiber characterized by being 25 times. 2. The composite spinning of the eluting component (A) and the residual component (B) which has no eluting property with respect to the solvent of the eluting component (A) or whose dissolution rate is sufficiently slower than that of the eluting component (A). At this time, the cross section of the obtained conjugate fiber is formed so as to surround the outer periphery of the eluted component (A) with the residual component (B), and the cross sectional area of the eluted component (A) is 30 with respect to the cross sectional area of the conjugate yarn fiber.
Melt-spinning using a spinneret device in which 1 part of the eluted component (A) is in communication with the outer periphery of the fiber through the residual component (B), and then drawn A method for producing a hollow fiber, which comprises subjecting the elution component (A) to an elution treatment.