JPH02277821A - Polyurethane conjugate fiber drawn yarn and production thereof - Google Patents

Abstract

PURPOSE:To obtain the title drawn yarn having eccentric cross section etc., through such processes that just before delivering a molten polyamide through a spinneret olifice, a molten polyurethane is eccentrically inserted from above in a bias fashion, and both the components are passed through the olifice followed by delivery through an enlarged channel. CONSTITUTION:Just before delivering a molten polyamide through a spinneret olifice 5, a molten polyurethane 3 is eccentrically inserted from above in a bias fashion, and both the components are passed through said olifice 5 followed by delivery through an enlarged channel 6, thus obtaining the objective crimpy drawn yarn. The present yarn has the following characteristics: (1) having eccentric cross section of such a shape that the polyurethane component is almost sheathed by the polyamide component; (2) <=1000(pref. 500)/kg in the number of fish-eye; (3) pref. 7-25% in boiling water shrinkage; (4) high in adhesiveness between the polyamide and polyurethane components: and (5) suitable for stockings, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a crimped polyurethane composite fiber, a method for producing the same, and a tubular knitted fabric such as stockings using the composite fiber.

(Prior Art) It is known that a fiber in which a polyamide component and a polyurethane component are eccentrically composited in the same filament has excellent crimpability (Japanese Patent Publication No. 55-22570).
No. 55-27175). Side-by-side composite fibers have excellent crimp performance, but have problems with the adhesion of the two components and adhesion between the polyurethane components.

On the other hand, although kidney type core-sheath type composite fibers have solved the problems of side-by-side type composite fibers, they have the disadvantage of poor crimpability.

Additionally, both the side-by-side type and the kidney type have the problem of fish eyes due to poor polyurethane melt stability during spinning.

Fish eyes refer to locally thick areas in the drawn yarn after spinning, winding and drawing, and can cause poor stretching and twisting properties of undrawn yarn and poor quality of products such as stockings.

In this document, the number of fisheyes refers to the number of fisheyes that is calculated by counting the cross-sectional diameter of the single fibers constituting the drawn yarn and converting it into the number per 1 kg of fiber.

(Problems to be Solved by the Invention) The purpose of the present invention is to solve the problems of conventional side-by-side composite fibers consisting of a polyamide component and a polyurethane component, such as poor adhesion and poor abrasion resistance of the two components, and adhesion between the polyurethane components. It is an object of the present invention to provide a conjugate fiber that solves the problem and has superior crimp performance and abrasion resistance compared to kidney-type conjugate fibers. A second purpose is to significantly reduce fish eyes by fluidizing and orienting the polyamide/polyurethane composite polymer at the constriction section.

(Means for Solving the Problems) The polyurethane composite fiber of the present invention is a composite fiber drawn yarn in which a polyamide component is eccentrically joined in a shape such that a polyurethane component is mostly wrapped in a cross section of the fiber, and A polyamide/polyurethane eccentric composite fiber drawn yarn characterized in that the number of eyes is 1.000 or less/kg, preferably 500 or less/kg, and in a preferred embodiment, the polyamide/polyurethane eccentric composite fiber drawn yarn has , the Sumoto shrinkage rate is 5 to 17%. Further, in the manufacturing method of the present invention, when melt-spinning a composite fiber in which a polyamide component and a polyurethane component are eccentrically joined, the flow of the molten polyamide component is controlled immediately before the flow of the molten polyamide component is discharged from the spinneret orifice. , the polyamide component is inserted eccentrically from the upper part obliquely with respect to the flow direction of the polyamide component, and the combined molten polymer flows are squeezed and passed through an orifice, and then discharged through the enlarged channel again.

Among the conventionally known polyurethane/polyamide composite fibers, the side-by-side type has the disadvantage that the adhesion of the composite side component is insufficient, resulting in peeling due to bending and abrasion during the processing process or product wear, and the physical properties deteriorate. This is to cause a decline. Another drawback is that polyurethane melts and solidifies slowly, so the polyurethane components exposed on the fiber surface stick together, and the spun and wound yarns adhere to each other, making it impossible to unwind. In addition, in kidney-type polyurethane/polyamide composite fibers as shown in Figure 3 in which the polyurethane component is eccentric, the polyamide component completely wraps the polyurethane component, so the high shrinkage rate polyurethane component and the low shrinkage rate polyamide component are separated. There is a drawback that the crimp development force caused by the difference in shrinkage rate is inferior.

Furthermore, even in the combination of polyamide-based components and polycarbonate-based polyurethane components, which are said to have relatively good adhesion, their adhesion is still insufficient, and the two components may be mixed during the yarn manufacturing process or when wearing stockings, etc. A phenomenon of peeling appears. For example, in a kidney type core-sheath type filament as shown in Fig. 3, elongation, bending, friction,
External stress such as heat treatment causes self ~ C2 and C1' ~ C2'
Concentrate on the narrow part of , and cut and peel along the line connecting C1 to C2'.

In the m-fiber cross-sectional shape of the present invention, the polyamide component largely wraps around the polyurethane component, and since the thickness of the polyamide component in the circumferential direction gradually decreases, stress concentration as described above occurs. It is possible to obtain excellent adhesion between the polyamide and polyurethane components without easily peeling off both components, and to suppress adhesion of the polyurethanes of the spun and wound yarn.

The cross-sectional shape of the composite fiber of the present invention is, for example, as shown in FIG. 2, where A is a polyamide component and B is a polyurethane component. In Fig. 2, the polyurethane portion exposed on the outer periphery of the cross section is d, and the occupancy rate of the exposed polyurethane portion on the outer periphery of the fiber is 25% or less, preferably 3 to 15%.
%.

The spinneret used in the present invention is characterized by having a constricted part in the polyamide/polyurethane joint flow path, and when L is the length of the hole with respect to the hole diameter of the constricted part flow path, L
/D is preferably in the range of 1.0 to 3.0. Furthermore, the pore diameter of the constricted flow path after polyamide/polyurethane bonding is 0.20 to 0.45 mm.

Preferably, the diameter is in the range of 0.25 to 0.40 mm, and after the flow path at the constricted part, the flow path expands into a trumpet shape across the discharge hole, and the diameter of the discharge hole is preferably in the range of 0.5 to 0.7 mm. preferable. By providing a constriction part in the polyamide/polyurethane joint flow path and reducing its diameter to 0.20 to 0.45 mm, the molten composite can be flow-oriented and the fish eyes of the composite fiber can be significantly reduced. can.

By the method of the present invention, conventionally at least about 2,000 pieces/k
1.000 pieces/g of composite fiber fish eyes/
It can be significantly reduced to 500 pieces/kg or less, preferably 500 pieces/kg or less. The diameter of the constriction part is 0.45mm+
If it exceeds , the fisheye deterrent effect is insufficient;
If the diameter is less than 0.20 mm, the pressure loss at the throttle part will be large and it will not be suitable for actual operation.

Examples of the polyurethane used in the present invention include polyester polyurethane, polycaprolactone polyurethane, and polycarbonate polyurethane. Among these, a thermoplastic polyurethane elastomer having a hardness of 90 to 100 measured according to the Shore hardness A measurement standard JIS K6301 is suitable.

Polyurethane having a hardness of 90 or less has difficulty in balancing the melt viscosity with polycapramide.

The polyurethane composite fiber of the present invention preferably has a water production shrinkage rate of usually 5 to 30%, more preferably 7 to 25%. If it exceeds 30%, it will shrink significantly during the heat treatment process after knitting, resulting in insufficient dimensions of the product, while if it is less than 5%, sufficient crimp will not occur even after heat treatment after knitting, and the stockings will lack elasticity. .

The eccentric composite fiber of the present invention can be produced by separately melting a thermoplastic polyurethane elastomer and polycapramide, and then using a composite spinning die as shown in FIG. 1, for example. The polyurethane introduced into the guide groove 1 and the polyamide introduced into the guide groove 2 are guided to flow paths 3 and 4, respectively, and then the polyurethane is injected obliquely from above with respect to the flow direction of the polyamide to form an eccentric junction flow. The fiber flows down to the constriction section 5, passes through the enlarged channel again, and is discharged from the discharge hole 6, forming a composite fiber having a cross section as shown in FIG.

Then, after stretching, it is subjected to a relaxation heat treatment under specific conditions and rolled up into a cot or cheese.

After melt-mixing the polyisocyanate compound during melt spinning,
A polyurethane elastomer obtained by composite spinning to generate a crosslinked structure in the molecule is also preferable since it has excellent heat resistance, crimpability, and adhesion to polyamide.

The polyamide of the present invention is a polycondensate obtained by ring-opening polymerization of ε-caprolactam, and also includes a polymer obtained by copolymerizing 30 mol% or less of a component copolymerizable with ε-caprolactam and Tam.

The relaxation heat treatment is preferably performed continuously at a relaxation rate slightly higher than the water production shrinkage rate measured for the drawn yarn. If the relaxation rate during the relaxation heat treatment is lower than the water-making shrinkage rate of the drawn yarn, the crimping of the wound raw yarn will be weak; on the other hand, if the relaxation rate is much higher than the boiling water shrinkage rate, there will be a spring in the heat treatment system. Small wavy crimps appear that look like they have been stretched.

Relaxation heat treatment methods include a method in which the tube is heated by running inside a hollow tube heater using air as a heat medium, a method in which the tube is heated by running on a hot plate, and the like.

The fineness of the single filaments constituting the composite fiber of the present invention is 3 to 30 d, and the number of filaments is 1 to 10,
The total fineness is preferably 5 to 50 d. In particular, as stocking threads requiring transparency, the total fineness is preferably in the range of 5 to 30 and the number of d1 filaments is in the range of 1 to 6. If the filament-forming single fiber fineness force is less than 3 d, the durability when wearing stockings is insufficient. On the other hand, if it is larger than 30d, the texture of striking and knocking becomes hard. Note that the term "stockings" as used in the present invention includes all of over-the-knee stockings that reach above the knees, full-length stockings that extend to the base of the thighs, and pantyhose that combine a panty section and a stocking section.

(Effects of the Invention) By the production method of the present invention, it is possible to obtain a polyurethane composite fiber that has excellent crimp performance and abrasion resistance, has significantly reduced fish eyes, and has improved workability and quality. . In addition, the yi fiber of the present invention can be used singly, in combination, in combination, in combination,
It can be used in combination with other fibers such as polyamide fibers, cotton threads, or polyurethane covering yarns by known methods such as interlacing, interlacing, and interweaving, and is suitable for textile products such as stockings, tights, and women's underwear. .

(Example) In the following Examples and Comparative Examples, each characteristic value was measured as follows.

The shrinkage rate, elongation rate, and abrasion resistance, which indicate crimp performance, were measured as follows.

After the undrawn yarn is subjected to stretching and relaxation heat treatment, the yarn is reduced to a thickness of approximately 100 mm.
0 Denny Nope Shaped into a skein approximately 50cm long, 10g/d
Apply a load of , and convert this length to the original fabric p. shall be.

Next, a load of 1 g is applied, and a crimp treatment is performed in boiling water for 10 minutes, and after being left for day and night, the length β1 is measured with a load of 1 g applied. The shrinkage rate is calculated according to the following formula (1).

Shrinkage rate (%) = (I!, l!,)/f, xlooo (
1) The elongation rate is 250 mg on a sample made into a skein in the same way.
A load of 10 g/d was applied, the length was treated in boiling water for 10 minutes, and the length β2 was measured after being left for day and night, and the length β3 was measured using the following formula (2). be done.

Extension rate (%) CR5-R2) #22X100 (2
) Abrasion resistance is determined by circular knitting the fibers after stretching and relaxation heat treatment.
Abrasion was repeated continuously under a load of 1 kg, and subsequent peeling of the two components on the surface of the knitted fabric was observed and evaluated using a microscope. Grade 3: No wear and peeling up to 3000 times, Grade 4: 50
No wear and peeling up to 00 times.

Example 1 Nylon 6 with a relative viscosity of 2°35 was used as the polyamide, and the soft segment was polycarbonate as the polyurethane.
The present invention A-F uses a mixed polymer of poly 1.6 hexane adipate 7/3 to melt-spun composite fibers using a composite spinneret with a discharge hole diameter of 0.50 mm and different diameters of the converging portions.
).

Comparative Example G is an example of a composite form of the eccentric kidney-core sheath shown in FIG. Note that the composite ratio of polyamide and polyurethane is 1/1 in terms of fiber cross-sectional area ratio.

In addition to using the side-by-side composite form shown in Figure 4,
Polyurethane composite fibers were obtained in the same manner as in the present invention (
Comparative Example H).

In addition, a polyurethane composite fiber was obtained in the same manner as in the example except that a composite die without a constriction part was used (Comparative Example (■)).

Next, the wound undrawn yarn is stretched using a stretching machine equipped with a heating plate having a length of 20 cm between two rollers (of the two rollers, the 10th roller is a heating roller). After stretching with heated rollers at a speed of 400 m for 7 minutes and a stretching ratio of 3.50 times, the material was introduced into a relaxation heat treatment device with a 100 cm heating plate installed between two rollers, and heated at a delivery roller speed of 400 m for 7 minutes. The plate temperature was fixed at 105°C, and the material was subjected to relaxation heat treatment at a drawing roller speed of 376 m for 7 minutes, and then rolled up into a cot. 2 filaments) were obtained. The appearance of the cotsup showed gentle wavy crimp, and even when the yarn was unwound from the cotsup, there was no change in the form of the crimp, and the gently wavy crimp remained.

Table 1 shows the manufacturing conditions and yarn characteristic values of drawn yarns from composite fibers obtained in each example and comparative example.

As can be seen from Table 1, the smaller the diameter of the aperture of the composite nozzle, the more the fisheye of the composite system decreases and the pressure loss increases. In relation to pressure loss, the orifice diameter is 0.
．． 20~0.45m+m is required, and 0.25~0.
35mm is desirable.

It can be seen that the composite system obtained by the present invention is superior to the side-by-side type in terms of wear resistance and prevention of undrawn yarn sticking.

Example 2 The stocking raw yarn of Example 1 was knitted into the leg and foot parts of a 40 seamless stocking knitting machine at a rotational speed of 9 QQrpm. As a result, the knitting was possible without any problems and the stocking quality was good.

On the other hand, with raw yarn I with many fish eyes, the knitting machine caused skipped stitches, yarn breakage, or knitting tension fluctuations, resulting in 900
Stable knitting was not possible under the rpm conditions.

Example 3 Using 13d/3f kennel yarn as stocking raw yarn and bulky crimped yarn of Example 1, legs were made with a knitted fabric alternately knitted by a 40 seamless stocking knitting machine (rotation speed 600 rpm). A stocking having a section and a foot section was manufactured. The obtained stockings were stretchable and had excellent transparency, and had a beautiful appearance with few scratches.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view of a composite spinneret suitable for the method of the present invention, FIG. 2 is a cross-sectional view of a polyurethane composite fiber produced by the method of the present invention, and FIGS. The figure is a cross-sectional view of a conventionally known composite fiber.

Claims (1)

[Scope of Claims] 1. A composite fiber drawn yarn in which a polyamide component is eccentrically joined in a shape such that a polyurethane component is mostly wrapped in a cross section of the fiber, which has a fish eye of 1,000.
A polyamide/polyurethane eccentric conjugate fiber drawn yarn characterized in that the polyamide/polyurethane eccentric composite fiber has a weight of less than 1 kg/kg. 2. The drawn polyamide/polyurethane eccentric composite fiber yarn according to claim 1, which has 500 fish eyes/kg or less. 3. The polyamide/polyurethane eccentric composite fiber drawn yarn according to claim 1, which has a boiling water shrinkage rate of 5 to 30%. 4. The eccentric composite fiber drawn yarn according to claim 1, wherein the polyurethane component is exposed over 25% or less of the outer circumference of the fiber and is wrapped in the polyamide component. 5. When melt-spinning a composite fiber in which a polyamide component and a polyurethane component are eccentrically joined, just before the flow of the molten polyamide component is discharged from the spinneret orifice, the flow of the molten polyurethane component is changed to the flow of the polyamide component. A polyamide/polyurethane eccentric composite fiber is inserted eccentrically from the upper part diagonally with respect to the direction, and the combined molten polymer flows are squeezed and passed through an orifice, and then discharged through a re-enlarged flow path. Production method. 6. The polyamide component is eccentrically joined in a shape that wraps most of the polyurethane component in the fiber cross section, the number of fish eyes is 1,000 or less/kg, and the shrinkage rate is 5 to 30%. A hojaly knitted with a yarn comprising a polyamide/polyurethane eccentric composite fiber drawn yarn.