JPS6014122B2 - Method for manufacturing polyester sliver - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing polyester sliver.

More specifically, the present invention relates to a method for producing a sliver for spun yarn that is made of polyester staple and has high strength, low elongation, and is uniform. Traditionally, filament and polyvinyl alcohol-based fiber spun yarns have been mainly used in fields that require high strength and low elongation properties, such as industrial applications and sewing thread applications, and polyester spun yarns have rarely been used. It has not been.

The first reason for this is that polyester fibers have high strength and low elongation, making them difficult to comb, and 100% spun yarns such as Zaranipo and Lyester have poor yarn quality.

That is, the short fiber strength of commonly used polyester staples is 5 to 6 tanodenier and the elongation is 15 to 20%, which is compared to 7 to IM/20%, which is comparable to vinylon or filament.
In order to achieve high strength and low elongation with a denier and elongation of around 10%, it is necessary to perform high-strength stretching in the tow manufacturing process or use tips for high viscosity, which reduces operability, quality, and price. From various aspects, there were many problems before it could be put to practical use industrially.

Furthermore, due to the physical properties of the fibers, it is difficult to produce spun yarns of good quality using conventional spinning processes, as they tend to produce draft spots, fluff, slubs, and neps. Met. The object of the present invention is to eliminate such drawbacks, that is, to achieve high strength,
The object of the present invention is to obtain a method for producing a sliver made of polyester staple that is optimal for producing a uniform spun yarn with low elongation.

This purpose is to bring an unstretched tow made of polyester fiber into contact with a first heating element heated above the glass transition point, to perform primary stretching at a stretching ratio of 70 to 95% of the natural stretching ratio, and then to a stretching ratio of 70 to 95% of the natural stretching ratio. The second heated to 24 pi 0
30 to 50% of the primary stretching ratio by contacting with a heating element.
A method for producing a polyester sliver, which is characterized by subjecting the tow to secondary stretching at a stretching ratio of Both refer to heating pins with a diameter of 15 mm to 15 mm, or heating plates having a curved surface equivalent to that of the heating pins.

). Hereinafter, the method for producing polyester sliver of the present invention will be explained in more detail with reference to the drawings.

Conventionally, it has been well known that the unstretched tow 2 is stretched in two stages to increase its strength, but as shown in FIG. It was usual to carry out the stretching by contacting the 5, 8, and 10 are first, second, and third stretching rollers, respectively.

In this case, due to non-uniform contact of each fiber with the hot plate or non-uniformity of heat transfer based on the thickness of the tow, the drawing points of each fiber are drawn by arc-shaped curves e, e as shown by AB'C. ′. Furthermore, even if the fibers are heated uniformly, the drawing point varies among individual fibers because the heating section is long. Furthermore, from point B where the toe touches the heating plate to stretching point B', the toe undergoes thermal history with a poor degree of orientation, making it impossible to achieve effective orientation. Not only is this undesirable because it tends to cause single thread breakage, but it is also difficult to make all the fibers that make up the tow have high strength and low elongation, or tension differences occur between individual fibers, which can cause cut spots. becomes. Furthermore, due to the difference in physical properties between the periphery and center of the tow, group breaks occur during tension cutting, resulting in uneven tension cutting, resulting in sliver spots, and in some cases, group breaks can occur continuously throughout the tow. You won't even be able to hold back. In contrast, a process schematic diagram showing an example of the method for manufacturing polyester sliver of the present invention is shown in the second example.
As shown in the figure.

In FIG. 2, the stretched tow storage can 1 stores the
The uniform unstretched tow 2 passes through a guide 3 and a straightening tow bar 4 to form a uniform sheet in the transverse direction, and is then supplied to a primary stretching zone a by a first stretching roller 5.

The unstretched tow supplied to the first stretching zone a runs in contact with the heating element 6 heated above the glass transition point, and then
The natural stretching ratio of the unstretched tow is 70 by the stretching roller 8.
The primary drawing is performed at a drawing ratio of 95% to 95%, and the drawing points of each fiber are distributed within a narrow band having a longitudinal direction perpendicular to the direction of travel of the tow. If the primary stretching ratio is less than 70% of the natural stretching ratio of the unstretched tow, an unstretched portion will remain during stretching, and uniform stretching will not be possible, and if it is greater than 95%, it will be difficult to achieve high strength.

The primarily drawn tow is then sent to the secondary drawing zone b via the second drawing roller 8, runs in contact with the second heating element 9 heated from 170 to 240 o'clock, and then passes through the third drawing roller 10. Then, the fibers are subjected to secondary stretching at a stretching ratio of 30 to 50% of the primary stretching ratio so that the stretching points of each fiber are distributed within a narrow band having a longitudinal direction perpendicular to the direction of toe movement, and then heat set. Tension heat setting is performed by the heating element 11. If the secondary drawing temperature is lower than 170qC, high strength cannot be achieved, and if it exceeds 240qo, if there is a single fiber break, the fiber will fuse on the heating element and become impossible to draw, or the fiber will be fused and cut during the stand. Undesirable cause. In addition, when the secondary draw ratio is less than 30% of the primary draw ratio, or 50%
When the size is larger, it is difficult to increase the strength and reduce the elongation, which is not preferable. The heating element for heat setting may be either a contact type or a non-contact type, and may not be used depending on the case. The tow stretched in the above manner does not substantially stop its progress. The sliver is drafted by about 15 times and then drafted, then corrected drafting and drafting are performed by modified fist-cutting loafs 14 and 15 in correction zone d, and concentrated by calendar rolls 16 to produce an uncrimped sliver. 17 and is stored in can 18.

In the sliver manufacturing method of the present invention, the heating bodies 6 and 9 are preferably pin-shaped heating bodies having a diameter of 15 to 150 ribs.

Moreover, instead of such a pin-shaped heating element, a heating element such as a hot plate having a curved surface similar to that of the pin-shaped heating element may be used on the tow entry side. In the first drawing step and the second drawing step of the method for producing a sliver of the present invention described above, each fiber is drawn so that the drawing points are distributed within a narrow band having a longitudinal direction perpendicular to the direction in which the tow travels. It is necessary to apply

That is, as shown in FIG. 3, it is necessary to draw the fibers so that the necking lines f, f' formed by gathering the drawing points of each fiber are within the narrow bands g, g' indicated by diagonal lines. The width 1 of the narrow belt castles g, g is preferably within 5 to 6 ribs, preferably within 3 sides. By performing the first and second stretching in this way, there is almost no difference in the thermal history of each fiber that makes up the tow, and the properties are uniform.The degree of orientation of each fiber is also high, resulting in high strength and low elongation. It becomes possible to obtain a degree of tow. In addition, if the diameter of the pin-shaped heating element is less than 15 mm, the heat capacity is insufficient and uniform stretching is relatively difficult, but if the diameter exceeds 15 mm, the stretching should be done so that the stretching points are distributed within a narrow band. It becomes difficult to apply.

According to the method for producing a sliver of the present invention described above, a uniform undrawn tow can be drawn uniformly, the degree of crystallinity and orientation can be made high, and the degree of elongation can be made high and the strength can be reduced. A new sliver with high symmetry, high strength, and low elongation can be obtained by directly cutting a uniform tow.

Furthermore, compared to the conventional sliver manufacturing process, which is complicated, such as oil production, drawing, crimping, drying, and stapling, the process is shortened to about 1/3, and the drawing zone and tension cutting zone are made more compact. Costs are halved and productivity is improved, resulting in significant cost reductions.

In addition, since the obtained sliver is uniform and has high quality, it is possible to omit the pre-spinning process altogether or to pass it through a paper spinning machine in the first roving process. It is possible to exit. In addition, the natural draw ratio as used in the present invention refers to the stress-elongation characteristics of the undrawn yarn constituting the undrawn toe.
This is the value obtained by dividing the yarn length at a point exhibiting the same stress as the yield point by the yarn length before elongation.

Example 1 20 unstretched polyester tows of 80,000 denier with a natural draw ratio of 3.4 times (20 single fibers with a total twill of 1.9 (denier) after drawing) were supplied, and the primary draw ratio was set to a natural draw ratio of 3.4 times. At 3.0 stitches, which is 90% of the stretching ratio, the diameter is 6 m, and the temperature is 90 qC.
Dry heat first stretching is carried out in contact with a heating pin, and then a diameter of 8
After dry-heat secondary stretching at a temperature of 21,000 and a stretching ratio of 1.20 times, which is 36.6% of the primary stretching ratio, using a zero skin heat pin, punch cutting was performed at a tension-cutting ratio of 5.0 times, and the material was stapled.
Next, perform a modified fist cut with a 1.6" sound, and the thickness is 6.0 yen/
m slivers were obtained.

In this stretching, the stretching points were distributed within a narrow band with a width of 3 skins or less. The short fibers of the sliver have a strength of 7.98 mm/d and an elongation of 11.3%, which is higher than the conventional product's strength of 6.1 mm/d and elongation of 20.3%. Met.

Next, apply the two slivers to the rover to obtain a 0.50
I made the roving yarn for Yu/Ai, and applied 1000 tons of lacquer on a ring fine loom using a 52x draft to create a 1/100th yarn.

The yarn breakage during spinning was 80 yarns/100 yarns, which was comparable to the conventional yarn.

Furthermore, the yarn quality has a Worcestershire unevenness u% of 12.0% (1 coefficient 1.20), and a general ring yarn (1'100) has a u=1
6 to 18% (1 coefficient 1.55 to 1.74). Three of the threads were combined and twisted on a desk at a ratio of 80 to make a sewing thread.The strength and elongation of the thread was examined, and the strength was 1.3.
kg, elongation of 5.3%, and strength of 0.9 to 1.0% compared to conventional similar yarns.
Compared to 0k9 and elongation of 15-18%, it exhibited medium-high strength and low elongation properties. On the other hand, when weaving was carried out using flat hot plates with a length of 20 skins in the primary and secondary stretching parts instead of hot pins, and with the other conditions being exactly the same as those described above, the stretching in the primary stretching The necking line, which is a collection of points, had an arc shape that was convex in the traveling direction, and there was a difference of 23 sides between the center and the periphery, and several hundred single yarns were broken during the secondary drawing.

Furthermore, mass breakage occurred in the center of the tow during tension cutting. The short fiber strength of the sliver thus obtained is up to 7
．． It was of low quality with wide variations, with a minimum of 4.8 m/d, an average of 5.9 m/d, and a strong fluctuation rate of 34.8%. Example 2 Ten unstretched polyester tows (42,000 denier) with a natural stretching ratio of 3.2 were supplied,
For the primary and secondary stretching, heating pins with a diameter of 5 mm were used to obtain stretched tows under various conditions, and the tows were cut under the same conditions to obtain slivers.

At this time, the conditions for the primary stretching were a hot pin temperature of 8030°C and a stretching ratio of 2.7 times (82% of the natural stretching ratio), and the conditions for the secondary stretching were a heating pin temperature of 230°C and a stretching ratio of 1.29 times (primary stretching The sliver obtained by the production method of the present invention with a magnification of 48%) has an elongation of short fibers of the sliver of 12.2%,
Strength? ．． It has high strength of 3/d and low elongation.
The sliver was of high quality with a thickness of 0.33#' and a Worcestershire irregularity of 3.8%. In addition, the elongation of the short fibers of the sliver obtained by setting the draw ratio of the secondary drawing to 1.62 times (60% of the primary draw ratio) and keeping the other conditions the same has a low elongation of 9.8%. was achieved, but the strength was 6.2 pm/d, which was not much different from the conventional product.

In addition, the short fiber strength of the sliver obtained under the same conditions except that the hot pin temperature of the secondary drawing was 160 qC was 60 qC.
．． 5, the elongation was 12.5%, and high strength was not achieved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the stretching state when performing two-stage stretching using a conventional flat hot plate, and FIG. 2 is a process schematic diagram showing an example of the method for producing polyester sliver of the present invention. FIG. 3 is an explanatory diagram of the stretching state in the method for producing polyester sliver of the present invention. 1: Unstretched tow storage can, 2: Unstretched tow, 3: Guide, 4: Adjusting tow bar, 5: First stretched loaf, 6: Heating body, 8: Second stretched loaf, 9: Heating body, 10: 3rd stretched loaf, 11: heating element for heat setting, 12: 1st rate cut loaf, 13: 2nd tension cut. - Fu, 14, 15: Modified tension cut low fu, 16: Calendar roll, 17: Sliver, 18: Kensu, 19:
Hot plate, a: primary stretching zone, b: secondary stretching zone, c:
tension cutting zone, d: correction zone; Figure 2: Figure 3

Claims (1)

[Scope of Claims] 1. An unstretched tow made of polyester fiber is brought into contact with a first heating element heated to a temperature higher than the glass transition point, and subjected to primary stretching at a stretching ratio of 70 to 95% of the natural stretching ratio,
Next, the tow is brought into contact with a second heating element heated to 170 to 240°C, and subjected to secondary stretching at a stretching ratio of 30 to 50% of the primary stretching ratio, and then substantially stopped in the direction of movement of the tow. A method for producing polyester sliver, which is characterized in that it can be cut without strain. (However, both the first and second heating bodies have a diameter of 15 mm to 1 mm.
It is made of a 50 mm heating pin or a hot plate having a curved surface equivalent to that of the heating pin. )