JPS621004B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hollow porous synthetic fiber with excellent hygroscopicity and a method for producing the same.

Synthetic fibers have excellent physical and chemical properties and are widely used for clothing and industrial materials, but their range of use is limited because they generally have poor hygroscopicity. Various methods have been proposed for imparting hygroscopicity to synthetic fibers, but the typical method is to add fine particles of a soluble substance to a fiber-forming synthetic polymer, spin it, and then treat it with a solvent to remove the soluble substance. This is a method of elution to form fine cavities in the fibers, and it is said that this method is especially effective when applied to hollow fibers (see Japanese Patent Publication No. 27608/1983).

As a result of intensive studies on this method, the present inventor found that in order to provide sufficient hygroscopicity, it is insufficient to form a sponge-like structure, and that a porous hollow structure having pores at least partially penetrating into the hollow part. It has been found that it is necessary to make it into a fiber. However, when attempting to produce such fibers using conventional methods, a large amount of components to be eluted and removed must be mixed, resulting in significantly poor spinning properties and a significant decrease in the strength of the final fibers. It is difficult to put it into practical use.

The present invention provides a hygroscopic synthetic fiber that eliminates these drawbacks and a method for producing the same, and the gist thereof is as follows.

(1) Fiber-forming synthetic polymer component A and synthetic polymer B that has an affinity with component A and has the same solubility.
A hollow composite fiber in which components mainly consisting of A hygroscopic synthetic fiber characterized by being a porous body with pores communicating with the hollow part.

(2) Fiber-forming synthetic polymer component A and synthetic polymer B that has an affinity with component A and has the same solubility.
Component A is mixed with synthetic polymer C having different solubility to form hollow composite fibers arranged radially alternately along the outer circumferential direction of the cross section of the fiber, and only polymer C is dissolved. A method for producing hygroscopic synthetic fibers, which comprises treating with a solvent to elute polymer C.

FIG. 1 is a diagram schematically showing a cross section of a hollow composite fiber before being subjected to solvent treatment in the present invention, in which the shaded area is the component A, and the shaded area is the component (mixed with polymer B and polymer C). B and C components) are shown.

Fig. 2 is a diagram schematically showing the appearance of the fiber obtained by the method of the present invention, in which the polymer C is eluted and becomes porous, and some of the pores penetrate to the hollow part. .

Although the hollow conjugate fibers of the present invention can be manufactured by conventionally known methods and apparatuses, they can be manufactured with good operability by melt spinning using a spinneret apparatus as shown in FIGS. 3 to 5. FIG. 3 is a cross-sectional view of the composite flow forming part of the mouthpiece device, in which the A component and the B and C components are separately metered and distributed and introduced from the introduction holes 1 and 2, and one component passes through the inside of the composite component 3. The other component is discharged separately from the discharge hole 4, and the other component is discharged from the composite part 3.
is divided by the slit groove 5 provided on the outer periphery of the spinning hole 6, and reaches the upper part of the spinning hole 6, forming a composite flow in which both components are alternately arranged at the upper part of the spinning hole 6. The fibers are spun through the holes 6 to form hollow composite fibers. The composite part has discharge holes 4 and slit grooves 5 arranged alternately, as the bottom view is shown in FIG. In consideration of the problem and the physical properties of the fibers finally obtained, 3 to 8 are appropriate.

In carrying out the method of the present invention, it is necessary to select an appropriate polymer. The polymer of component A and the polymer B must have mutual affinity and have the same solubility, and the same or similar polymers are used, but usually it is not necessary to prepare multiple types of polymers. The same polymer is used. These are polymers constituting the final fibers, and polyamides such as nylon 6 and nylon 66, and polyesters such as polyethylene terephthalate and copolymers thereof are most suitable.

Polymer C mixed with polymer B may be any polymer as long as it has a different solubility from component A (and polymer B), but even if mixed in a large amount, composite fiber formation is easy, and polymer It is preferable that the polymer does not form a very micro-uniform mixture with the polymer B, and it is suitable that it has a poor affinity with the polymer B and does not have an extreme difference in melt viscosity. In this sense, polymer B is polyamide and polymer C is polyester,
Optimally, polymer B is polyester and polymer C is polyamide. However, this is only a typical example, and other polymers C include water-soluble polymers such as polyethylene glycol, olefin-modified poval, and modified polyamide, and organic solvent-soluble polymers such as polystyrene.

The mixing ratio of polymer B and polymer C must be such that when polymer C is eluted and removed, there is a sufficient amount of polymer C to form pores that penetrate to the hollow part of the fiber. If the amount of polymer C is too large, the strength of the fiber will decrease, so the maximum amount of B and C components is
A suitable proportion is 80%, preferably 40 to 60%, of polymer C.

When mixing Polymer B and Polymer C, it is necessary to prevent the mixture from becoming too micro-uniform as described above, but in general, in melt spinning, the polymer in the form of chips is fed to the melt extruder. The chips may be mixed in batches, and the size and shape of the chips may be changed as necessary. The molten polymer may also be mixed by passing it through a static mixing device with a suitable number of elements.

When manufacturing hollow composite fibers, the size and number of pores in the final fiber can be controlled by adjusting the proportion of polymer C in the B and C components, the number of divisions between the A component and the B and C components, and the discharge ratio. can do.

The hollow composite fiber obtained through the spinning and drawing process is made into a fabric as it is or after undergoing false twisting, etc., and is treated with a solvent that dissolves only the polymer C.
Most of the polymer C is eluted to form porous hollow fibers with excellent hygroscopicity. In some cases, the yarn may be treated with a solvent before being made into a fabric, or it may be used as a staple in addition to being used as a filament yarn. As a solvent, formic acid or sulfuric acid is suitable when Polymer C is polyamide, strong alkali such as sodium hydroxide is suitable when Polymer C is polyester, water is suitable when Polymer C is a water-soluble polymer, and xylene is suitable when Polymer C is polystyrene. , an organic solvent such as trichlorethylene is used.

According to the method of the present invention, since the substance to be eluted and removed is a polymer, it is possible to add a large amount of component A.
Since composite spinning is performed in conjunction with this method, spinning performance is not impaired. Since the pores formed by the elution of polymer C penetrate into the hollow part of the fiber, the hygroscopicity of the fiber becomes very good, and the strength of the fiber increases because there are no pores continuous in the axial direction of the fiber. Does not decrease.

Example Nylon 6 with an intrinsic viscosity of 1.2 was used as component A and polymer B, and relative viscosity was used as polymer C (equal weight mixed solvent of phenol and tetrachloroethane,
B.C.
Composite spinning was carried out with the mixing ratio of the components being 1/1 by weight.

The spinneret device shown in FIGS. 3 to 5 (however, the number of discharge holes 4 and slit grooves 5 of the composite part 3 is 3 each)
The spinning temperature was set at 280°C, the discharge ratio of the A component and the B and C components was set to 1/1, and the discharge amount was adjusted to give a denier of 50 denier after stretching.
It was wound at a speed of m/min.

Next, cold stretching was performed using a stretching pin at a stretching ratio of 2.6.

Both spinning and drawing were good, and the obtained yarn had a strength of 4.2 g/d, an elongation of 41.2%, and a hollow ratio of 9.6%.

When this yarn was knitted into a tube, immersed in a 25% aqueous sodium hydroxide solution, and treated at 95°C for 1 hour, the polyester component was eluted and many concave portions were formed on the fiber surface, and some ~6μ holes were formed through to the hollow part.

The hygroscopicity of this knitted material was 14.5% at 20° C. and 65% RH, which was found to be significantly superior to the 4.4% of the blank nylon 6 knitted material.

[Brief explanation of the drawing]

Fig. 1 is a diagram schematically showing a cross section of a hollow composite fiber before solvent treatment, Fig. 2 is a diagram schematically showing the appearance of the fiber obtained by the method of the present invention, and Figs.
FIG. 5 is a diagram showing a spinneret device for spinning hollow composite fibers, FIG. 3 is a sectional view, FIG. 4 is a diagram showing the shape of the spinning hole, and FIG. 5 is a bottom view of the composite part.

Claims (1)

[Scope of Claims] 1. A fiber-forming synthetic polymer component A and a component mainly composed of a synthetic polymer B having an affinity with component A and having the same solubility are arranged in the outer peripheral direction of the cross section of the fiber. Hollow composite fibers are arranged radially alternately along the length of the fiber, the former component being a solid body, and the latter component being a porous body with at least some pores communicating with the hollow part. Features a hygroscopic synthetic fiber. 2. The hygroscopic synthetic fiber according to claim 1, wherein polymer component A and polymer B are the same polymer. 3 A fiber-forming synthetic polymer component A, a component obtained by mixing a synthetic polymer B having an affinity with component A and having the same solubility, and a synthetic polymer C having a different solubility from component A, are used to form fibers. A hygroscopic synthetic fiber characterized by forming hollow composite fibers arranged radially alternately along the outer circumferential direction of a cross section, and treating the polymer C with a solvent that dissolves only the polymer C to elute the polymer C. manufacturing method. 4. The method for producing a hygroscopic synthetic fiber according to claim 3, wherein polymer B and polymer C are polymers with poor affinity for each other. 5. The method for producing a hygroscopic synthetic fiber according to claim 3, wherein polymer component A and polymer B are the same polymer. 6 Polymer component A is polyamide, and polymer C
The method for producing a hygroscopic synthetic fiber according to claim 5, wherein is polyester. 7. The method for producing a hygroscopic synthetic fiber according to claim 5, wherein the polymer component A is polyester and the polymer C is polyamide.