JPS6330403B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing yarns similar to yarns spun from staple fibers from yarns consisting essentially of continuous filaments.

It is known to treat certain types of continuous filament yarns by various methods to form yarns that are somewhat similar to yarns spun from staple fibers. Typical prior art methods of breaking a filament such that its broken end projects outside the yarn bundle are disclosed in U.S. Pat. No. 3,857,232;
No. 3,967,441, each of which is incorporated herein by reference. GB 971,573 discloses a similar method, in which it is stated that the cut filament ends do not protrude from the bundle, but are entwined within the bundle of threads. In each of these and other known methods of breaking filaments, the breakable filament is substantially uniform from end to end. That is, there is no preferred break location along the breakable filament, and thus the break is not as controlled as desired.

In accordance with the present invention, these and other drawbacks of the prior art are eliminated by using a raw yarn having a preferred break section along the breakable filament.

According to a first aspect of the invention, each repeats along its length from a narrow section of small cross-sectional area to a thick section of large cross-sectional area, which is at least 25% larger than the small cross-sectional area. A raw material yarn is made of a plurality of continuous non-circular cross-sectional filaments, each having a cross-sectional area that varies with each other, and whose thick and thin portions are out of phase from filament to filament along the length of the yarn. A process is provided for producing yarn-like yarns comprising drawing, in which the filaments are repeatedly broken primarily in thin sections to give broken ends protruding from the bundle.

According to the invention, the yarn is false-twisted during drawing.

According to another aspect of the invention, the yarn is false twisted and heat set during drawing.

According to another aspect of the invention, the average distance between successive thickenings along each filament is between 2 cm and 20 m, and this is preferably
The length is 20cm to 5m.

According to other aspects of the invention, the large cross-sectional area is at least 100% larger than the small cross-sectional area;
and this is preferably 300% to 500% of the smaller value
It is between.

Other aspects of the invention are set forth in part below and will be apparent in part from the following description of the accompanying drawings.

In the accompanying drawings, FIG. 1 is a longitudinal sectional view of a preferred embodiment of a spinneret that can be used for producing the raw material yarn of the present invention. Figure 2 is the first view when looking up from below.
FIG. 3 is a bottom plan view of the spinneret shown in FIG. FIG. 3 is a cross-sectional view of a filament according to one embodiment of the present invention.
FIG. 4 is a side view of the melt stream exiting the spinneret of FIG. 1 in accordance with an embodiment of the present invention. Fifth
The figure is a graph illustrating denier variation along a representative filament according to certain embodiments of the present invention. and FIG. 6 is a graph illustrating the distribution of the fluctuations illustrated in FIG. 4 for a representative multi-orifice spinneret in accordance with certain embodiments of the present invention.

Although the raw yarn for the method of the invention is specifically described using polyester polymers, it is understood that certain embodiments of the invention are generally applicable to the family of melt-spun polymers. It should be. "Polyester" as used herein
The term refers to fiber-forming polymers of which at least 85% by weight can be prepared by reaction of dihydric alcohols with terephthalic acid.
Polyesters are typically produced by direct esterification of ethylene glycol and terephthalic acid or by transesterification of ethylene glycol and dimethyl terephthalate.

Figures 1 and 2 illustrate preferred embodiments of spinneret designs that can be used to achieve all aspects of the present invention. The spinneret includes a large borehole 20 formed in the upper surface 21 of the spinneret plate 22. A small borehole 24 is formed at the bottom of the large borehole 20 and on its lateral portions. A large capillary 26 extends from the bottom of the large bore 20 in the opposite lateral portion from the small bore 24 and connects the bottom surface 28 of the plate 22 with the bottom of the large bore 20. . A small capillary 30 connects the bottom of the borehole 24 with the surface 28. Capillaries 26 and 30 are each inclined at 4° from vertical and thus have an included angle of 8°. Drill hole 20 has a diameter of 0.113 inch (2.87 mm), while bore hole 24 has a diameter of 0.052 inch (1.32 mm).
It has a diameter of Capillary 26 has a diameter of 0.016 inches (0.396 mm) and a diameter of 0.146 inches (3.81 mm).
mm), while the capillary 30 has a length of
It has a diameter of 0.009 inches (0.229 mm) and a length of 0.032 inches (0.813 mm). Land 32 separates capillaries 26 and 30 where they emerge on surface 28, and this
It has a width of 0.0043 inches (0.108 mm). Plate 22 has a thickness of 0.554 inches (14.07 mm). Capillaries 26 and 30, together with boreholes 20 and 24, constitute coupling orifices for spinning a variety of new and useful filaments according to the present invention, as will be described in more detail below.

As a specific example, a molten polyester polymer of conventional textile molecular weight is metered at a temperature of 290 DEG C. through a spinneret having a coupling orifice 34 as specifically disclosed above. The amount of polymer processed is
8 per filament at a spinning speed of 3400 yards/min
The melt stream is then cooled into filaments with transversely directed cooling air in the conventional manner.

Under these spinning conditions, significant development occurs as shown in FIG. Because of the construction of the spinneret configuration, polymer flowing through the smaller capillaries 30 has a greater velocity than flow through the larger capillaries. The velocity and moment of the combined streams exiting each coupling orifice, and the angle at which the streams converge outside the spinneret, are slower after the point where the streams first meet and come together. Stream 34 travels in a substantially straight line, while each smaller and faster stream 36 meanders back and forth between each successive point of attachment 38 with its associated larger flow. It begins to form a loop. This effect is
This flow can be easily observed using a stroboscopic beam directed just below the spinneret surface 28. As the melt flow accelerates away from the spinneret, the slower flow reaches the point of attachment 38
and the loop of the faster flow straightens until the faster flow joins the slower flow in succession. The slower flow is narrower between the first bond points than at the first bond point, and the resulting merged flow has a larger cross-sectional area at the first bond point than in the intermediate portion of these points. have The resulting combined flow is then solidified by the lateral cooling air and further narrows down somewhat into the filament 40.

Each solidified filament 40 has a non-circular cross-sectional area that varies repeatedly along its length. When using the spinning conditions described qualitatively in FIG. 5, the filament cross-sectional area varies repeatedly at a frequency of approximately 1 per meter.
However, this can be changed by changing the spinning conditions and the structure of the spinneret passage.

Because of the small differences between the coupling orifices, the temperature gradients in the spinneret, and other similar variations from exactly the same treatment for each set of streams, multi-orifice spinnerets typically have several giving some different frequencies to the production streams and filaments. An example of this is shown qualitatively in FIG. It is shown here that various orifices give slightly different frequencies as measured by stroboscopic examination of the coupled flow directly below the face of the spinneret. In the resulting multifilament yarn, each filament runs along its length from a thin section with a small cross-sectional area to a thick section with a large cross-sectional area (at least
25% larger). An improved yarn-like effect in the final textured yarn is obtained when the large cross-sectional area is at least 100% larger than the small cross-sectional area. Optimal results are when the large cross section is 300% to 500% of the small cross section
Obtained when the value is between.

The raw yarn is processed into a friction aggregate of the type disclosed in U.S. Pat. No. 3,973,383 (herein incorporated by reference).
is simultaneously draw textured on a Barmag FK-4 texturing machine using as false twist yarn production equipment. Stretching ratio is 385ypm
It is set to 1.6 at a winding speed of (approximately 350 m/min). Both heaters are set to 200°C. Overfeed to the second heater is 10.47%,
And the overfeed to the winder is 6.79%. The assembly speed is set so that the thread tension is equal just before and after assembly.

The resulting yarn has a number of filament break points, mainly in the thin section, and the broken ends protrude from the yarn bundle. This filament is
It is broken with much better control than in the above-referenced patents, and because of the variable denier, fabrics made from this resulting yarn are similar to those made from prior art yarns of the same average denier/filament. It is much softer and has the feel of a luxury product. This soft touch is
This is particularly evident when the cross-sectional area of the thick part of the filament is at least 100% larger than that of the thin part, and values of 300 DEG C. to 500% or more are particularly preferred for this.

[Brief explanation of the drawing]

In the accompanying drawings, FIG. 1 is a vertical cross-sectional view of a preferred embodiment of the spinneret that can be used for producing the raw material yarn of the present invention, and FIG.
FIG. 3 is a bottom plan view of the spinneret of FIG. 3, and FIG. 3 is a cross-sectional view of a filament according to one embodiment of the invention;
FIG. 4 is a side view of the melt stream exiting the spinneret of FIG. 1 in accordance with an embodiment of the present invention;
6 is a graph illustrating the variation in denier along a representative filament according to an embodiment of the present invention, and FIG. 6 is a graph illustrating the variation illustrated in FIG. 4 for a representative multi-orifice spinneret according to an embodiment of the present invention. It is a graph explaining the distribution of.

Claims (1)

[Claims] 1. Each of the plurality of filaments with a non-circular cross-section repeatedly changes along its length from a thin part with a small cross-sectional area to a thick part with a large cross-sectional area (however, the cross-sectional area is at least 25% larger than the small cross-sectional area), and the thick and thin sections are out of phase from filament to filament along the length of the yarn and repeat primarily in the thin section. A yarn-like yarn characterized in that it consists of a plurality of quasi-continuous non-circular cross-section filaments that are broken to produce broken ends, the broken ends protruding from the bundle of yarns. 2. Claim 1, wherein the filament has alternating S-shaped and Z-shaped helical crimp along its length.
Thread described in section. 3. Yarn according to claim 1, characterized in that the average distance between successive thick sections along each of the filaments is between 2 cm and 20 m. 4. The yarn according to claim 3, wherein the average distance is between 20 cm and 5 m. 5. Yarn according to claim 1, characterized in that said large cross-sectional area is at least 100% larger than said small cross-sectional area. 6. Yarn according to claim 2, characterized in that the large cross-sectional area is at least 100% larger than the small cross-sectional area. 7 The large cross-sectional area is 300 times larger than the small cross-sectional area.
% to 500%. 8 The large cross-sectional area is 300 times larger than the small cross-sectional area.
% to 500%. 9(a)(1) metering the polymer through a coupling orifice to form a plurality of molten polymer streams moving at different extrusion rates; and (2) converging and narrowing the plurality of molten polymer streams. (3) cooling the combined stream into a non-irregular cross-sectional filament, and forming a plurality of combined streams with repeating thick and thin sections along its length; pulling the filament, possibly comprising a plurality of filaments with a non-circular cross-section, each of which has a narrow section with a small cross-sectional area to a thick section with a large cross-sectional area along its length; (where the large cross-sectional area is at least 25% larger than the small cross-sectional area) and the thick and thin sections vary from filament to filament along the length of the yarn. producing out-of-phase raw yarn, (b) heating and false-twisting the raw yarn at a draw ratio selected such that a plurality of filaments with non-circular cross-sections break primarily at the narrow portion; A method for producing a spun yarn-like yarn, which comprises stretching. 10. The method of claim 9, wherein the large cross-sectional area is at least 100% larger than the small cross-sectional area. 11 The large cross-sectional area is smaller than the small cross-sectional area.
11. A method according to claim 10, characterized in that it is between 300% and 500%.