JPH03185146A - Liquid bath drawing treatment of acrylic fiber tow - Google Patents

Abstract

PURPOSE:To draw a large amount of tow in good productivity in a substantially zero state of end breakage and fluff by dividing acrylic fiber two through a yarn guide having specific surface roughness into specific thickness, drawing in a liquid bath and redoubling the divided tow. CONSTITUTION:Acrylic fiber two is divided through a yarn guide having <=10S, preferably <=6.3S surface roughness Hmax into <=35,000D/cm, preferably <=30,000D/cm thickness, introduced to a liquid bath and drawn. Then the divided drawn tows are collected and doubled again.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for liquid bath stretching treatment of acrylic fiber tow.

[Prior art] Conventionally, various methods for drawing synthetic fibers using heating bottles, hot plates, steam, liquid baths, etc. have been adopted, but there are many methods for drawing fiber bundles such as bundles or laminated fibers. Hot water or other liquid bath drawing is widely used, especially when it is necessary to uniformly draw a large amount of fiber bundles and prevent yarn breakage and fuzzing, such as in the case of band-shaped tow. (For example, JP-A-50-154531@publication, JP-A-58-180608@publication, JP-A-58-180627)
Publications, etc.).

However, in the above-mentioned liquid bath stretching, if the stretching speed is increased, or the tow width or tow thickness is increased, even in liquid bath stretching, so-called incomplete stretching occurs due to uneven heating of the tow. This causes problems such as yarn breakage and the generation of fluff, and as a result, the drawing operation has to be abandoned.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned problems of the prior art, and to reduce tension fluctuations within the yarn in liquid bath drawing of acrylic fiber tows having large tow widths and tow thicknesses. It is an object of the present invention to provide a liquid bath stretching method that enables stable and uniform stretching, thereby reducing the occurrence of yarn breakage and fuzz.

[Means for Solving the Problems] The above-mentioned problem of the present invention is that when an acrylic fiber tow is introduced into a liquid bath and stretched, the fiber tow is stretched through a yarn guide to a thickness of 35,000 strands/cm. This problem can be solved by the following liquid bath drawing method for acrylic fiber tow, which is characterized by dividing the yarn into yarn bundles, drawing them, and then doubling them.

Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIGS. 1 and 2 are schematic diagrams showing one embodiment of liquid bath stretching of an acrylic fiber tow according to the present invention.

As shown in the figure, a stretching bath 4 is provided between a supply roller 2 and a stretching roller 3 that rotates at a higher speed than the supply roller 2, and the continuous fiber tow 1 sent out from the supply roller 2 is divided into a predetermined thickness. , bath thread guide 5. 6. 7. 8
．． 9 and 10 into the bath liquid 11, and the stretching roller 3
Stretch by.

At this time, each fiber tow divided by the yarn guide has a thickness of 35,000 strands/cm or less, preferably 3.500 strands/cm or less. Stretch at 0.0000 mm/cm or less. Such split drawing allows stable and uniform drawing of a large amount of tow, and the occurrence of thread breakage, fuzz, etc. is reduced to virtually no occurrence. Moreover, it can be achieved with high productivity.

The thread guide used here preferably has a surface roughness of 108 or less, more preferably a surface roughness of 6.38 or less. As the octopus guide, any of the conventionally known rotary guides and fixed guides can be used.

It is desirable to divide the fiber tow in units of spindles, and the fiber tow is generally divided into about 2 to 5 parts.

In addition, hot water or hot water containing an appropriate surfactant is preferably used as the liquid bath in the liquid bath drawing of the fiber tow, and the temperature of this liquid bath is within the range of about 70 to 100'C, as known in the art. Liquid bath stretching conditions can be adopted.

Above, the method of the present invention has been described only for one-stage stretching using one liquid bath.
Of course, the above method can also be applied to so-called multi-stage stretching.

[Example] The present invention will be specifically described below with reference to Examples.

Example 1 Acrylonitrile was solution-polymerized according to a conventional method to prepare a spinning stock solution.

The obtained spinning dope was wet-spun into a 55% by weight dimethyl sulfoxide aqueous solution through 6 spindles with 12,000 holes to a total denier of 72,5000.

Using the drawing device shown in Fig. 1, the coagulated yarn was guided to a pair of fixed guides 5 and 6 provided at the upper stage of the liquid bath to draw the yarn for three spindles to a tow thickness of 3°10,000. D/rm, the remaining three threads were guided to the fixed guides 7 and 8 provided at the lower stage, and the tow thickness was also set to 31,000 threads/cm.
After that, a first stage stretching of 2.5 times is performed in a liquid bath at 80°C.

Next, all of the six upper and lower yarns were passed through a second liquid bath (not shown) equipped with a pair of fixed guides, and second-stage liquid bath drawing was performed at 98°C. At this time, a fixed guide with a surface roughness of ll1ax=0.8 was used.

The continuously drawn yarn thus obtained was washed with water, dried, and further subjected to dry heat drawing treatment so that the single yarn denier of the final yarn was 2 d, and taken off at a take-up speed of 10071'L/min.

The fineness fluctuation rate, number of undrawn yarns, and number of fluffs of this yarn were measured, and the results are shown in Table 1.

Comparative Example 1 In Example 1, the eye metal 6 was drawn only to the fixed guides 5 and 6 for liquid bath drawing, and the tow thickness was set to 62,000 D/r:m, and the other conditions were the same as in Example 1. A yarn with a yarn denier of 2d was produced.

The fineness fluctuation rate, number of undrawn yarns, and number of fluffs of this yarn were measured, and the results are also listed in Table 1.

As is clear from Table 1, according to the method of the present invention, all of the fineness fluctuation rate, the number of undrawn yarns, and the number of fluffs are significantly improved compared to the comparative example because it provides extremely excellent uniform drawability. I understand.

(Hereinafter, blank spaces) Table 1 Example 2 A coagulated yarn obtained in the same manner as in Example 1 was drawn using the drawing device shown in Fig. 1, and the yarn for two ferrules was placed in the upper stage of a liquid bath. The thread is guided through a pair of fixed guides 5 and 6 installed so that the thickness of the tow is 27,000 strands/cm, and the remaining four threads are guided through a pair of fixed guides 7 and 8 installed at the lower stage to form a tow. A single yarn with a denier of 2d was produced under the same conditions as in Example 1 except that the thickness was 35,000 strands/cm.

The final yarn at this time was sampled for each fiber bundle divided in the first stage drawing, and the fineness fluctuation rate, number of undrawn yarns, and number of fuzz were measured for each fiber bundle, and the results are shown in Table 2.

(The following is a margin.) Table 2 Example 3 Single yarn denier 2 under the same conditions as Example 1, except that the final take-up speed was changed as shown in Table 3.
A yarn of d was produced. The fineness fluctuation rate, number of undrawn yarns, and number of fluffs of the yarns were measured and shown in Table 3.

Example 4 A yarn having a single yarn denier of 2d was produced under the same conditions as in Example 1, except that the surface roughness of the yarn guide in the bath was changed as shown in Table 4.

The fineness fluctuation rate, number of undrawn yarns, and number of fluffs of the yarns were measured and shown in Table 4.

[Effects of the Invention] The method of the present invention includes the following steps in liquid bath stretching of acrylic fiber tow:
By dividing the fiber tow into a predetermined thickness and then drawing it, a large amount of fiber tow can be drawn stably and uniformly, so that thread breakage, fuzz, etc. are reduced to a state where there is virtually no fiber tow. Moreover, it has remarkable effects on the production of acrylic fibers, such as the ability to achieve liquid bath drawing of a large amount of fiber tow with high productivity.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic diagrams showing one embodiment of liquid bath stretching of an acrylic fiber tow according to the present invention. 1: Continuous fiber tow 2: Supply roller 3; Stretching roller 4: Stretching bath 5, 6. 7. 8. 9.10: Bath yarn guide 1
1; Bath liquid

Claims (2)

[Claims] (1) When introducing an acrylic fiber tow into a liquid bath and drawing it, the fiber tow is passed through a yarn guide to a thickness of 3.
A method for liquid bath drawing treatment of acrylic fiber tow, which comprises dividing the yarn into the following yarn bundles and drawing them at 50,000 D/cm, followed by doubling. (2) The method for liquid bath stretching treatment of acrylic fiber tow according to claim (1), wherein the surface roughness of the yarn guide is H_m_a_x=10^S or less.