JPH0214014A - Production of fine sized polyester yarn - Google Patents

Abstract

PURPOSE:To obtain the subject yarn with a slight generation of heat-fusing part of yarns mutually, capable of being drawn at higher draw ratio, without depression of dignity and uniform by subjecting specific polyester undrawn yarn to flow drawing and necking drawing in turn. CONSTITUTION:At first, a polyester having >=0.5mol% ester unit derived from dicarboxylic acid or diol containing metal salt sulfonate group and mainly containing ethylene terephthalate unit is used to obtain polyester undrawn yarn having modified cross section. Next, said undrawn yarn is subjected to flow drawing preferably at a temperature of 73-90 deg.C, then subjected to necking drawing to obtain the aimed yarn. Besides, as dicarboxylic acid or diol containing metal salt sulfonate group, 3,5-di(carbomethoxy)sodium benzenesulfonate, etc., is preferable.

Description

[Detailed description of the invention] Technical field The present invention relates to a method for producing fine-grained polyester fibers.

More specifically, the irregular cross-section polyester undrawn fibers are first
The present invention relates to a method for producing polyester fibers with ultra-fine fineness and 11 fewer adhesion areas by performing flow drawing (super draw) in one stage and neck drawing in the second stage.

Prior Art As a method for producing polyester fibers with ultra-fine fineness, undrawn fibers are flow-drawn in the first stage and neck-drawn in the second stage, as disclosed in, for example, Japanese Patent Publications No. 11832-1983 and No. 13342-1983. Are known.

In addition, a polyester fiber containing a specific amount of poly(alkylene glycol) with a specific molecule m as unstretched mH is flow-stretched to 3 times or more in moist heat, and then neck-stretched to a single yarn fineness of 0.5 de or less. A method for producing ultrafine fibers with good stretching conditions has also been proposed in Japanese Patent Publication No. 55-6734 and Japanese Patent Publication No. 55-14171.

It is true that ultrafine fibers such as polyester IJAM containing poly(alkylene glycol) can be produced with good stretching conditions, but when flow stretching is performed in a tow state, especially at a high stretching ratio of 5 times or more, flow stretching Due to the exothermic action caused by this, the m-grains tend to melt together and form adhering fibers, which has the drawback of significantly lowering the quality of the product obtained after stretching. For example, when subjected to a spinning process to make spun yarn for clothing, fibers with a large number of adhesion areas as described above tend to drop during the carding process, causing unevenness in the web or sliver, and breakage in the subsequent spinning process. This causes winding of the yarn and rollers, and the resulting spun yarn becomes non-uniform, resulting in a low-quality spun yarn. Similarly, it is undesirable for use in stuffing and non-woven fabrics as it has many web rings.

Purpose The present invention was made against the background of the above circumstances,
The purpose is to provide a method for producing ultrafine fibers that can be drawn at a higher draw ratio with less occurrence of adhesion areas.

In order to achieve the above object, the present invention provides a method for producing fine-grained polyester IIN by first drawing polyester undrawn fibers and then neck drawing them, in which the polyester undrawn fibers are coated with at least one metal. It is made of a polyester mainly composed of ethylene terephthalate units containing 0.5 mol% or more of ester units derived from a dicarboxylic acid or diol containing a salt sulfonate group, and the cross-sectional shape of the unstretched polyester van is irregular. It is characterized by:

In the present invention, a fiber made of polyester that can be flow-stretched is used as the unstretched mII.

As such a polyester, a polyester mainly composed of ethylene terephthalate units containing 0.5 mol % or more of ester units derived from a dicarboxylic acid or diol containing at least one metal salt sulfonate group is preferably used. The sulfonate group-containing polyester has the formula R-
Z-R03M (However, in the formula, Z is a trivalent aromatic or aliphatic hydrocarbon group, and R is -o-cffi-class alkyl, (C1l
z ) n OH,0(CH2) n
-[0(CH2)n]Ill-OH and -
selected from the group consisting of C-[O(CH2)n Ill -OH, where n and I are integers greater than 1,
M is a metal) A dicarboxylic acid or diol containing a metal salt sulfonate group as represented by M is a metal and at least one difunctional acid such as isophthalic acid, adipic acid, p-oxybenzoic acid or a derivative thereof and/or diethylene glycol, By copolymerizing in the presence or absence of a dihydric alcohol such as propylene glycol, 1,4-butanediol, or 1,4-bishydroxymethylcyclohexane, or by copolymerizing the polymer thus obtained with repeating units. It is made by blending it with a polyester that is at least 85 mole percent ethylene terephthalate.

Particularly preferred dicarboxylic acids or diols containing a metal salt sulfonate group represented by the above formula for use in the present invention include sodium 3,5-di(carbomethoxy)benzenesulfonate, 3,5-di(carbomethoxy) ) Potassium benzenesulfonate, sodium 1,8-di(carbomethoxy)naphthalene-3-sulfonate, potassium 2,5-di(carbomethoxy)benzenesulfonate, 2,5-bis(hydroxyethoxy)benzenesulfonic acid Potassium etc. can be mentioned. The sulfonate group-containing nisful unit in the raw material polyester must be at least 0.5 mol%, preferably at least 0.5 mol% and 5 mol%.
The following shall apply. The intrinsic viscosity of the raw material polyester is 0.30~
A short period of 0.55, particularly 0.32 to 0.45 is desirable.

In the present invention, undrawn polyester fibers having irregular cross sections are used as undrawn polyester fibers. Figures 1 to 24 show examples of the cross-sectional shapes of the irregular cross-section undrawn polyester fibers used in the present invention, and in particular, at least one fiber as shown in Figures 4 to 23. In the case of fibers with a cross-sectional shape having protrusions,
The effect is remarkable.

In addition, the llH of the irregularly shaped hollow cross section as shown in Figs. 17 to 24 is useful not only for preventing adhesion, but also for the bulkiness and heat retention of the obtained product, and for post-processing such as clothing molding and spinning. It is also preferable from the viewpoint of opening properties in the process.

As the spinning nozzle for spinning these undrawn polyester fibers with irregular cross-sections, those used for spinning ordinary fibers having a fineness of 3 de or more after drawing may be used as they are, and they are extremely small in size. There is no need to use a special nozzle that requires complicated construction.

The polymer temperature during spinning is set to the optimum temperature depending on the type of polyester, but the lower the temperature, the sharper the irregular cross-sectional shape. However, if the polymer temperature is too low, the birefringence of unstretched IaH will increase and the flow stretchability will decrease, which is not preferable. Further, if the cooling conditions for the spun yarn are strengthened, the degree of irregularity increases, but the flow stretchability tends to decrease as well.

In the present invention, such undrawn fibers can be used in the form of multifilament yarn or tow.
Further, thin undrawn fibers having an undrawn single filament denier of 5 de or less can also be used.

The first stage of flow stretching is usually carried out in a hot water bath at 70 to 100°C (
It is preferable to carry out the process using an oil solution (which may contain an oil agent).

Stretching by dry heat is not preferable because the heat generated by flow stretching is not absorbed by the heating medium and a large number of adhesive threads are produced.

The temperature of the first stage (flow) drawing bath is most preferably 73 to 90°C, and at this temperature 0. Ig/de or less (usually 0.0
Flow stretching without molecular orientation can be performed at a low tension of 2 to 0.05 ff/de). At a relatively low temperature, the occurrence of adhesion portions is slightly reduced, which is a more preferable condition.

The first stage (flow) drawing ratio is desirably 3.0 times or more in order to obtain ultrafine denier fibers.

In the present invention, the first stage stretching ratio can be increased to 15 times or more, and in some cases can be increased to 20.0 times or more. Therefore, in the present invention, the first stage draw ratio can be selected from a wide range depending on the denier required for the product fiber. For example, the undrawn single yarn denier is 5 de, and the second stage (neck) draw ratio described below is 3 times. In the case of , the product denier is 0.
To make it 5de, the first stage stretching ratio is 3.3 times, 0.2d.
To make it e, just multiply it by 8.3.

The residence time of the fiber in the first-stage drawing bath varies depending on the bath temperature and the content of ester units containing metal salt sulfonate groups, but is generally 0.1 seconds or more (particularly preferably 0.5 seconds or more). It is sufficient if it is present, and therefore it becomes possible to increase the stretching speed.

Since the Si which has been stretched in the first stage (flow) as described above has a degree of orientation comparable to that of the unstretched I-miscellaneous material, it is neck-stretched in the second stage to give it the necessary a-miscellaneous properties.

For the second stage (neck) drawing, a normal polyester fiber drawing method can be adopted, and in the case of tow, 60 to 80
It is preferable to stretch the film by 2.5 to 4.5 times in a warm water bath at .degree. Since the drawing temperature in this second stage drawing is lower than that in the first stage drawing, it is preferable to cool the fibers with cooling rollers, cold water, etc. between the first stage drawing and the second stage drawing. This reduces thread unevenness and makes the quality more uniform.

Effects of the Invention As described above, according to the present invention, thermal F11 adhesion between fibers does not occur during flow stretching at high magnification, there is no deterioration in product quality, and it is possible to obtain a product with a uniform [1] fineness. can.

Obtained by the present invention! I-miscellaneous products are extremely useful in fields such as clothing, cotton filling, non-woven fabrics, artificial leather, and artificial fur.

Example 1 During transesterification polycondensation of dimethyl prephthalate and ethylene glycol, 3.0 mol of sodium 3.5-di(carbomethoxy)benzenesulfonate was added to dimethylene terephthalate, and the intrinsic viscosity [η] was reduced to 0. .3
A chip of copolymerized polyester No. 8 was obtained.

This was melt-spun at a spinning temperature of 270°C and a spinning speed of 900 m/min from an irregularly shaped hollow spinning nozzle with 700 holes.
．． Ode irregularly shaped hollow undrawn yarn was obtained. This undrawn yarn
The first stage drawing bath temperature was set at 81℃.
The tow was flow stretched 15 times at a feed rate of 15 m/min, and the tow was cooled to 40°C using a cooling cola.
, and then neck-stretched to 2.2 times in hot water at 70°C. Stretching was possible without any particular problem. The fibers after stretching had few adhering parts and the fibers were opened well.

Comparative Example 1 When spinning and drawing was attempted under the same conditions as in Example 1 except that the spinning nozzle was changed to a circular hole, the first stage draw ratio was 5.
When the drawing ratio exceeded 0 times, flow stretching was impossible, and when the 0th stage drawing ratio was 4.5 times, drawing was possible, but many adhering fibers were generated.

[Brief explanation of the drawing]

FIGS. 1 to 24 are diagrams showing examples of cross-sectional shapes of irregular cross-section undrawn polyester fibers used in the present invention. Figure 1 Figure 2 Mother Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (3)

[Claims] (1) In a method for producing fine-grained polyester fibers by flow stretching and then neck stretching undrawn polyester fibers, the undrawn polyester fibers are esters derived from dicarboxylic acids or diols containing at least one metal salt sulfonate group. 1. A method for producing a fine-grained polyester fiber, which is made of polyester mainly composed of ethylene terephthalate units containing 0.5 mol% or more of ethylene terephthalate units, and wherein the undrawn polyester fiber has an irregular cross-sectional shape. (2) The method according to claim 1, wherein the cross-sectional shape of the undrawn polyester fiber is irregularly hollow. (3) The method according to claim 1, wherein the undrawn polyester fiber has an irregular cross-sectional shape having at least one protrusion.