JP2001032129A - Production of cellulose acetate slub yarn - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cellulose acetate slub yarn in high spinning stability while preventing the breakage of yarn on a grooved take-up roll in the production of a cellulose acetate slub yarn using a grooved take-up roll. SOLUTION: A cellulose acetate slub yarn is produced by intermittently varying the take-up speed in the dry spinning of a cellulose acetate fiber using a grooved take-up roll having grooves on a part of the circumferential direction of the roll. The friction coefficient between the surface of the take-up roll and the fiber is set to <=0.5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a cellulose acetate thick and thin yarn.

[0002]

2. Description of the Related Art Conventionally, many thick and thin yarns having a difference in fineness in the longitudinal direction of fibers have been proposed, mainly polyester fibers. Generally, in order to form a difference in fineness in the longitudinal direction of the polyester fiber, a technique based on incompletely stretching a polyester undrawn yarn under specific conditions to cause a necking phenomenon is used,
There are many proposals and they have been put to practical use.

[0003] On the other hand, since cellulose acetate fibers are produced by dry spinning in which a spinning dope is discharged into a heated atmosphere, most of the solvent evaporates instantly when the spinning dope is discharged from a spinning nozzle, resulting in fiber formation. Therefore, there is no intermediate such as an undrawn yarn such as polyester fiber, and it is difficult to produce a thick and thin yarn by a technique based on the necking phenomenon. On the other hand, a method in which the take-off roller in dry spinning of cellulose acetate fiber is a grooved take-off roller, the take-off speed is intermittently reduced to form a thick fine portion, and a thick fine yarn having a fineness difference in the longitudinal direction of the yarn is obtained. Has been proposed in Japanese Patent Publication No. 3-9203.

[0004] However, in this method, although a cellulose acetate thick and thin yarn having a delicate slab-like appearance when obtained as a fabric is obtained, yarn breakage easily occurs on a grooved take-off roller and spinning stability is reduced. There is a problem of chipping.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing a cellulose acetate thick and thin thread using a grooved take-off roller, which prevents yarn breakage on the grooved take-off roller and reduces the cellulose acetate thick and thin thread. The object is to obtain good spinning stability.

[0006]

According to the present invention, in dry spinning of cellulose acetate fiber, a take-off roller having a groove in a part of a circumferential direction of the roller is used for taking-out after discharging, and a take-up speed is intermittently controlled. Wherein the coefficient of friction with the fiber on the surface of the take-off roller is adjusted to 0.5 or less when producing a thick and thin yarn.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In general, dry spinning of cellulose acetate fibers is performed by dissolving cellulose acetate flakes in a solvent such as acetone, a methylene chloride / methanol mixture or the like to prepare a spinning dope, and spinning the spinning dope from a spinning nozzle having a small pore diameter. It is discharged into heated air to evaporate the solvent to form a filament, and the filament is taken out to form a complete thread. It is determined by the discharge amount of the stock solution and the take-up speed. Accordingly, when the spinning stock solution discharge linear speed is constant, a yarn with a fine fineness can be obtained when the take-up speed is low, and a fine fineness can be obtained when the take-up speed is high.

[0008] In the present invention, the take-off of the filament after ejection in dry spinning is performed by using a take-up roller having a groove provided with a groove sufficient to drop the filament into a part of the circumferential direction of the roller. The speed is reduced intermittently, and a thick fineness portion is formed intermittently to produce a thick and thin yarn.

The method for producing a cellulose acetate thick thread according to the present invention will be further described with reference to FIGS. 1 and 2. FIG. 1 is a schematic view of an example of an apparatus for specifically producing the cellulose acetate thick thread according to the present invention. Reference numeral 1 denotes a spinning nozzle, 2 denotes a heating cylinder, 3 denotes an oil applying device, 4 denotes a traverse guide, 5 denotes a grooved take-up roller, and 6 denotes a winding device. In order to intermittently and randomly change the take-up speed in spinning, the take-up speed may be increased or decreased. However, it is preferable to use a means for decreasing the take-up speed in terms of yarn production stability. In order to reduce the take-up speed, it is preferable to use a grooved take-up roller. For example, as the grooved take-up roller 5, a grooved take-up roller as shown in FIG. 2 (a is a front view, and b is a side view) is shown. Used.

[0010] grooved take-up roller shown in FIG. 2, the depth in the portion circumferentially of the diameter D ₀ becomes roller of (D ₀ -
A groove having a depth of D ₁ ) is provided at an angle θ. The traverse guide 4 in FIG. 1 can move left and right around the groove of the take-up roller 5, and the moving means of the traverse guide 4 may be a mechanical type, an electric type, or the like as long as it can reciprocate at a random cycle. Either method may be used.

In FIG. 1, discharge from a spinning nozzle 1 is performed.
The thread formed by removing the solvent in the heating cylinder 2 is taken off by the grooved take-off roller 5 via the oil agent supply device 3,
The yarn is wound by the winding device 6, but when the grooved take-up roller 5 takes up the yarn, the position of the yarn on the grooved take-up roller 5 traverses left and right in accordance with the left and right movement of the traverse guide 4. Is temporarily dropped into the groove of the grooved take-off roller 5 or is taken on a groove-free surface of the grooved take-up roller 5.

Since the surface speed of the grooved take-off roller 5 at the groove portion is lower than that at the portion of the roller surface having no groove, a thick fine yarn is formed while the filamentary material falls into the groove. On the other hand, in a state where the thread is not dropped into the groove, a fine yarn is formed. Further, the depth of the groove clearly corresponds to the fineness difference between the fine fineness portion and the thick fineness portion of the yarn, and the fineness difference increases as the groove becomes deeper. Therefore, the fineness difference and the length of the large fineness portion are set according to the depth and length of the groove in the grooved take-off roller 5.

However, the grooved take-up roller 5
Is extremely deep, it is difficult for the thread to escape from the groove once the thread has fallen into the groove despite the movement of the traverse guide 4, so in the case of the method of the present invention, The groove does not cover the entire circumference of the take-up roller 5,
It is preferable that a part of the groove on the roller surface always forms the same surface as the roller surface having no groove.

In the method of the present invention, it is essential that the coefficient of friction between the grooved take-up roller and the fiber on the surface is 0.5 or less. When the coefficient of friction with the fiber on the surface of the grooved take-off roller is 0.5 or less, the thread-like body is traversed on the grooved take-up roller from a groove-free surface to a groove portion and from a groove portion to a groove-free surface by a traverse guide. The movement is extremely smooth, there is no winding around the roller, and the yarn breakage due to the winding can be prevented, and the cellulose acetate thick and thin yarn can be obtained with good spinning stability.

The coefficient of friction is as follows: the running yarn tension (T ₁ ) when the sample yarn was caused to contact and run at a contact angle of 180 ° on a cylinder of a metal surface having a diameter of 40 mm at a running speed of 25 m / min and an initial tension (T ₁ ) of 13 g. ₂ ) is measured and calculated by the following equation. Coefficient of friction = (T ₁ −T ₂ ) / (T ₁ + T ₂ )

When the friction coefficient of the grooved take-up roller surface exceeds 0.5, for example, when the roller surface is mirror-finished, the movement of the yarn on the take-up roller is caused by the frictional resistance and the yarn tension. Fluctuation occurs, and loosening at the time of fluctuation causes wrapping around the roller, and yarn breakage easily occurs.

The means for reducing the frictional resistance of the grooved take-off roller surface and the coefficient of friction with the fiber is not particularly limited, and a fluororesin processing or the like is used, but a friction coefficient of 0.3 or less can be easily obtained. A satin finish is preferably used. The surface of the roller that lowers the coefficient of friction is the surface with which the yarn is in contact, the surface of the roller surface without grooves, the bottom surface of the groove, and more preferably the side surface of the groove.

[0018]

The present invention will be described below in more detail with reference to examples.

(Examples 1 to 3) Cellulose triacetate flakes having an average acetylation degree of 61.3% were dissolved in a mixed solvent of methylene chloride and methanol to prepare a spinning dope having a solid concentration of 21.9% by weight. , Dry spinning device, pore size 30μ
m, after spinning from a spinning nozzle having 20 holes into a heating atmosphere at a temperature of 45 ° C., and forming the yarn, a groove having a maximum depth of 53 mm and a groove angle of 135 ° is provided on the roller surface as shown in Table 1. Diameter 212 with satin finish of various surface roughness (R _Z )
mm, a traverse guide moving cycle (one way) on the grooved take-off roller is 0.15 to 1.5 seconds, and a take-up speed is 150 to 300 m / min by a grooved take-off roller having a roller rotation number of 460 rpm. 84 dtex / 20f thick and thin yarns were obtained.

Each of the obtained thick and thin yarns has a length of 5 to 20 cm in the form of a yarn, a thickness of 1.9 to 2 times the thickness of the fine size, and an average of 81.2 to 81.7 dtex. And a fine fineness portion. Table 1 shows the coefficient of friction and the state of thread breakage on the grooved take-off roller surface, and all showed extremely good spinning stability.

Comparative Example 1 The procedure of Example 1 was repeated, except that the grooved take-off roller was replaced with a grooved take-up roller having a mirror-finished surface roughness (R _Z ) shown in Table 1 on the roller surface. 84dtex / 2 as in 1
0f thick thread was obtained. The obtained thick fine yarn has a length of 5 to 20 cm in the state of a thread, a thick fineness portion whose thickness is 1.9 to 2 times the fine fineness portion, and a fine fineness portion with an average of 81.2 dtex. Table 1 shows the coefficient of friction and the state of thread breakage on the surface of the grooved take-off roller used. The thread breakage was large and the spinning stability was extremely poor.

[0022]

[Table 1]

[0023]

According to the method of the present invention, in the production of cellulose acetate thick and thin yarn using a grooved take-off roller, thread breakage on the grooved take-off roller can be prevented, so that cellulose suitable for use in clothing can be used. Acetate thick and thin yarn can be obtained with good spinning stability, and can greatly contribute to improvement in productivity.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example of an apparatus for producing the cellulose acetate thick and thin yarn of the present invention.

FIG. 2 is a schematic view of a grooved take-off roller in FIG. 1, wherein A is a front view and B is a side view.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 spinning nozzle 2 heating cylinder 3 oil supply device 4 traverse guide 5 grooved take-up roller 6 take-up device

Claims (1)

[Claims] Claims: 1. In dry spinning of cellulose acetate fiber, a take-off roller having a groove in a part of a roller circumferential direction is used for taking-out after discharge, and a take-up speed is changed intermittently to form a thick yarn. In manufacturing, the coefficient of friction with the fiber on the surface of the take-off roller is 0.5
A method for producing a cellulose acetate thick and thin yarn, characterized by the following.