JPS62251B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Technical Field of the Invention The present invention relates to a method for producing alternating twisted and temporary twisted filament fiber yarn suitable for woven and knitted clothing.

(b) Prior art and its problems As for multifilament yarns subjected to temporary twisting, the most common so-called textured yarn is well known and commonly used. This processed yarn has excellent bulkiness, elasticity, and uniformity, but although it is uniform, it has little design effect, and the constituent filaments have little mutual cohesiveness, so they are difficult to process during weaving, weaving, and preparation. In some cases, the permeability of fabrics may be a problem, and separate treatments such as interlacing, threading, and gluing are often required to improve convergence, and fabrics have poor drapability and are rough to the touch. There are also other flaws.

As another prior art, an intermittent unresolved alternate twist yarn is also well known as a temporarily twisted multifilament yarn. When forming undissolved nene, the tentatively twisted area is heated at high temperature to cause strong fusion between the constituent filaments. Since it is a yarn, when it is subjected to tension, the S twist part and the Z twist part tend to cancel each other out, making it morphologically unstable, and after the cancellation, a yarn structure like the so-called processed yarn described above is formed. One point is that the difference in heat shrinkage between the unresolved part and other parts is large, and when the fabric goes through the finishing process, the unresolved part will pop out on the fabric surface, creating so-called horns, which is undesirable. Because the difference in form is too large, the characteristics are strongly expressed in the fabric, and there are defects such as lack of versatility.

C. Purpose of the present invention The present invention improves the above-mentioned conventional technology, and creates a yarn that has fewer fused parts, is soft and drapeable, is bulky, has a wool-like feel, and has natural irregularities similar to natural fibers. It is on offer.

D. Structure of the present invention In other words, the structure of the present invention is as follows: ``An undrawn multifilament yarn made of thermoplastic synthetic fiber is subjected to a temporary twisting process while being drawn below the natural drawing ratio to form intermittent unresolved alternating twists.
Next, a second stretching is carried out in a range where the total stretching ratio is equal to or less than the natural stretching ratio, and the alternating orientation S and Z
A method for producing alternating twist and temporary twist yarn, characterized by partially offsetting the twist. ”.

A more detailed explanation will be given below using the drawings.

FIG. 1 is a schematic diagram showing one embodiment of the present invention. In this figure, a yarn Y unwound from a winding body 1 of thermoplastic undrawn multifilament yarn is stretched between a supply roller 2 and a stretching roller 6, and is given a temporary twist by a temporary twist device 5. A part of the temporary twisting area is heated by the heating device 3. The drawing ratio at this time (hereinafter referred to as DR1), that is, DR1 = yarn feeding speed of the drawing roller 6 / yarn feeding speed of the supply roller 2 is determined by the natural drawing ratio of Y before engaging the supply roller 2 (hereinafter referred to as NDR). ) or less, that is, DR1<NDR (1). Next, a second stretching is performed between the stretching roller 6 and the second stretching roller 8. The drawing ratio at this time (hereinafter referred to as DR2), that is, DR2 = yarn feeding speed of second drawing roller 8 / drawing roller 6
The yarn feeding speed is expressed as the total drawing ratio (DRT), that is, DRT = yarn feeding speed of second drawing roller 8 / supply roller 2
The yarn feeding speed is set to be less than or equal to the natural draw ratio, that is, in a range such that DRT=DR1×DR2<NDR (2). In addition, in this second drawing, when the yarn is drawn due to the convenience of the processing machine, or when this second drawing is performed in multiple stages, etc., when the drawing roller 6 and subsequent ones engage two or more yarn feeding rollers. , the second stretching roller 8 is the roller that feeds the yarn fastest after the stretching roller 6. Next, the winder 9 winds the specially twisted yarn into a spool 10 to complete the process.

E Effects of the present invention When temporarily twisting a thermoplastic multifilament yarn to obtain an intermittent unresolved alternating twist yarn, the following can be achieved by using an undrawn yarn and taking the range of formula (1). A characteristic thread can be obtained.

It is possible to form an unresolved part with an extremely high twist density, that is, almost equal to the twist density of the tentative twist area, and therefore to have a high twist density in the over-resolved part.

An intermittent unresolved yarn with an alternating weave to which sufficient weave shrinkage is imparted can be obtained.

C. The constituent filaments have high elongation.

D. Can be obtained in a weakly fused state.

Preferred temporary twisting conditions for bringing out the above characteristics prominently are described below.

a NDR×0.75<DR1<NDR×0.93 b The heating temperature can be selected to be lower than the softening point of the material. The lower limit varies depending on the value of DR1 and the characteristics of the material, and is difficult to determine here, but it is easy to determine by experiment.

c The temporary twist number can be selected relatively freely.

d As for the temporary twisting device, a friction type (direct type) is preferable to a spinner type (indirect type). Temporary twisting can be performed without ballooning the yarn, and a long (large amount) of unresolved parts can be formed.

e It is preferable to provide a grafting plate between the heating device and the temporary twisting device. It has the effect of stopping the occurrence of ballooning. It is more preferable to add a cooling effect to this grafting plate, since high-speed processing can be performed. This is an embodiment as shown in 4 in FIG.

By drawing the intermittent unresolved alternating twist yarn obtained by the temporary twisting process in the second drawing zone within the range of formula (2), the following characteristic yarn can be obtained.

(b) Weak fused bonds are further peeled off, resulting in alternating twist threads with extremely little fused bonding.

(b) Kenshrinkage becomes relatively easy to occur.

(c) The mutual contraction phases of the constituent filaments are relatively aligned.

(d) The difference in morphology between the unresolved part and the over-resolved part is reduced.

(e) The elongation of the constituent filaments is almost maintained at a high level.

(f) Tensile strength (shape stability of yarn) is improved.

The stretching conditions to bring out the above features are shown in equation (2).
The range of 1.03<DR2<1.18 is preferable.

Note that it is also possible to heat in the second stretching region. This is an embodiment as shown in 7 in FIG.

This will be explained below using examples.

Example 1 Melt spinning polyethylene terephthalate
Undrawn multifilament yarn was drawn at 3000 m/min, had a thickness of 240 denier, 48 filaments, and a natural draw ratio NDR of 1.63. this thread
While being stretched to 1.42 times, temporary twisting was performed at a temporary twisting rate of 2200T/m and a heating temperature of 235°C. Then, the yarn was drawn 1.07 times to obtain a yarn of the present invention.

This yarn had the following characteristics.

(a) It is soft with almost no fused parts.

(b) There was little difference in the yarn form between the unresolved part and the over-resolved part, resulting in natural-looking spots on the fabric, similar to natural fiber threads.

(c) It is bulky due to shrinkage.

(d) Excellent drapability due to uniform ken phase.

(e) The surface has less roughness. I think this is also because the Ken contracted phases are aligned.

(f) Feels like wool. I think this is because the fibers have high elongation and give a slight slimy feel.

(g) After making a woven fabric and applying the grain treatment, many grains appeared. This is thought to be because the twisting phases are aligned, so the torque in the twisting direction is strong.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one embodiment of the present invention. 1: Thread body of thermoplastic undrawn multifilament yarn, 2: Supply roller, 3: Heating device, 4: Yarn cooling device, 5: Temporary twisting device, 6: Stretching roller,
7: second heating device, 8: second stretching roller, 9: winder, 10: winding body of alternately twisted and temporarily twisted yarn,
Y: Thread.

Claims (1)

[Claims] 1. An undrawn multifilament yarn made of thermoplastic synthetic fiber is stretched at a rate below the natural draw ratio and subjected to temporary twisting to form intermittent unresolved alternating twists,
Next, a second stretching is performed in a range where the total stretching ratio is equal to or less than the natural stretching ratio, and the alternating orientations S and Z
A method for producing alternating twist and temporary twist yarn, characterized by partially offsetting the twist.