JPH0149808B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to a method for reducing the thickness of existing acrylic spun yarn by approximately doubling the yarn count.

<Prior art> In the case of conventional spun yarn, cotton yarn or polyester spun yarn can be produced up to an ultra-fine count of 100S or more.
In the case of acrylic spun yarn, 80S was considered to be the limit of fineness, and when a finer count than that was required, acrylic filament yarn had to be used. However, filament yarns have a problem in that they cannot provide the woolly feel and appearance of spun yarns.

The present inventors have devised a method in which the yarn count can be reduced to about twice the size by hot stretching acrylic spun yarn under constant tension in a softened state close to its glass transition point. Through this development, we succeeded in reducing the count of acrylic spun yarn to 160S, leading to this invention.

<Object of the Invention> An object of the present invention is to provide a method for producing a fine-count yarn that is even finer than the fine-count yarn of acrylic spun yarn that can be achieved by existing methods.

<Structure of the Invention> The purpose of the present invention is to double the acrylic spun yarn (original yarn) under a constant tension within the limit tension of the yarn in the presence of steam heated to a temperature near the softening point of the acrylic fiber. This is achieved by a method of fine-tuning acrylic spun yarn, which is characterized by stretching it to a certain point.

That is, when the raw yarn of acrylic spun yarn is heated and stretched under constant tension in a softened state, on the one hand, the polymer chain is destroyed and the molecules are rearranged, so that each fiber itself has a certain degree of elasticity. On the one hand, the filaments are elongated, and on the other hand, the fibers are rearranged among themselves, so that the yarn is finely divided as a whole. At that time, it is presumed that the above-mentioned state is fixed due to the penetration of free hydrogen, and thus the above-mentioned fineness phenomenon occurs.

In addition, the critical tension as used in the present invention refers to the tensile force at the moment when the raw yarn breaks when the raw yarn is gradually stretched.

<Example> The present invention will be described in detail below based on an example of the method for fine-tuning acrylic spun yarn according to the present invention.

Acrylic spun yarn (hereinafter referred to as "original yarn" in the present invention) that has not been previously heat-treated at a temperature near its softening point
) is placed in a vacuum setter under the same tension, and water vapor heated to the same temperature as the softening point of the acrylic fiber is injected to maintain a constant tension within the limit tension of the raw yarn. Tension is gradually applied for a short period of time to stretch the length of the yarn by approximately 20% to 150% (hereinafter referred to as "hot drawing"). When it is necessary to replenish, replenishment twisting is performed in advance before the hot stretching step or immediately after the hot stretching. In addition,
The acrylic fibers that have absorbed heat in the hot stretching process induce a cohesive effect similar to the felt properties of wool, so this supplementary twisting can be omitted unless a particularly high degree of strength and elongation is required. .

In order to further increase the bulkiness of the finely counted yarn obtained by the above method, the inside of the setter is cooled and relaxing with steam is performed in a tension-free state. This relaxing causes the length of the yarn to shrink by approximately 10 to 15%, thereby increasing bulkiness.

Next, specific examples of the method for reducing the number of acrylic spun yarns according to the present invention will be shown below.

Specific Example 1 (When supplementary twisting is not performed) Acrylic spun yarn (original yarn) with a limit tension of 150g
52S (Regular Bright) has a vapor pressure of 4 to 6 kg/cm ² and is heated to the softening point temperature of the acrylic fiber in the presence of water vapor heated to the softening point temperature of the acrylic fiber, under a tension of 50 gr for 2 to 3 lbs.
Stretch the yarn while maintaining it for 100 minutes.
%stretch. When the yarn was subjected to wet relaxing under no tension, a shrinkage of 15% occurred.

After repeating the above process twice, the yarn count was 104S.
An ultra-fine count acrylic spun yarn having a tensile strength of 100 to 200 gr and an elongation of 8.42% and an appearance similar to a filament yarn was obtained.

Specific Example 2 (When supplementary twisting is performed) 450t.pm, 52S acrylic spun yarn is supplementary twisted so that it has 900t.pm, and the length of the raw yarn is adjusted under the same conditions as in Example 1 above. As a result of stretching by 120%, we were able to obtain acrylic spun yarn with an average size of 115S. The tensile strength of this finely counted yarn was 140 gr.

<Effects of the Invention> Since the method for making acrylic spun yarn finer according to the present invention is configured as described above, it is simple and easy to make acrylic spun yarn finer in a wide range of 20 to 100%. can be done. By using this method, it is possible to obtain acrylic spun yarn with an ultra-fine count of 160S.

Claims (1)

[Claims] 1. In the presence of steam heated to a temperature near the softening point of the acrylic fiber, an acrylic spun yarn (original yarn) is stretched to about twice its original strength under a constant tension within the limit strength of the yarn. A method for making acrylic spun yarn finer in count. 2. Claim 1, characterized in that the number of twists lost or lost in the hot drawing process of the acrylic spun yarn (original yarn) is supplemented by twisting before or after the drawing process. Method described. 3. The method according to claim 1, wherein the stretched acrylic spun yarn is wet-relaxed in a substantially tension-free state. 4. A method according to claim 1, characterized in that the constant tension applied to the acrylic spun yarn (original yarn) is approximately 30% of the critical tension of the yarn.