JPS5922801B2 - Method for drawing polyamide fibers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drawing method for obtaining polyamide fibers having high strength and good dimensional stability.
The present invention relates to a two-stage stretching method in which a saddle-type heater is used in the second stage to perform hot stretching and thermal relaxation treatment at the same time.

A stretching method in which hot stretching and thermal relaxation treatment are carried out simultaneously using a saddle type heater is known from Utility Model Publication No. 42-2808 and the like.

In addition, in order to obtain high-strength polyamide fibers,
A step drawing method is used.

The present invention aims to obtain polyamide fibers with high strength and good dimensional stability by simultaneously carrying out hot stretching and thermal relaxation treatment using a saddle type heater in the second stage of a two-stage stretching method. Figure 1 shows a simplified diagram of the loading capacity.

The yarn 1 is wound 2 to 5 times around a top roller 3 that is frictionally driven by a yarn guide 2 and a feed roller 4, and is drawn in the first stage between a feed roller 4 having a drawing pin 5 and a draw roller 6. The first stage drawing ratio DR in the area
The draw roller 6 and separate roller T
(This is wound 4 to 8 times and supplied to the second stage drawing area.

The yarn 1 is drawn at a second drawing ratio DR2 in a second drawing area between a draw roller 6 and a draw roller 10 having a saddle heater 8 and a free roller 9.

The yarn 1 coming out of the draw roller 6 first contacts the right side of the saddle type heater 8 between the draw roller 10 and the free roller 9 (the thread is wound 3 to 9 times, and the draw roller 10 and the free roller A saddle type heater installed between the rollers 9 (2 sides per turn, 7 to 1 in total)
Nine surfaces are in contact and hot stretched.

The hot-drawn yarn 1 passes through a draw roller 10, contacts a free roller 9 on the left side of the saddle-type heater 8, passes through a free roller 9, passes through a yarn guide 11 without passing through a draw roller 10, and then reaches a ring 12 ( It is wound onto the bobbin 14 by the traveler 13 which is engaged with the material.

The saddle type heater 8 has a temperature of 160 mm for hot stretching and thermal relaxation treatment.
The draw roller 10 is heated to 100 to 200°C in order not to cool the yarn 1.

In addition, the thermal relaxation treatment is performed at a yarn tension of 2.0 to 8.0 during hot stretching between the free roller 9 and the draw roller 10. Since this is done by using the difference between Or/d and the yarn winding tension of 0.05 to 0.5 f/d, the free roller 9 adjusts the yarn winding tension between the draw roller 10 and the free roller 9. Thermal relaxation treatment area (to put it simply, in other words, the yarn 1 easily slides on the free roller 9) is often used to have a surface with a low coefficient of friction such as a satin finish. There is.

However, in the drawing method shown in FIG. 1 (in this case, when the yarn tension is under high tension of 2.0 to 8.Or/d, the yarn 1 and the saddle heater come into contact many times, friction l
This increases the number of single thread breaks.

When cutting a single thread, it is easier to cut the DR2 than by cutting the DR2, but if you reduce the DR2, the DR
It is necessary to increase l, which has the disadvantage of increasing yarn breakage and single yarn breakage in the first stage drawing zone.

The present invention provides a stretching method that can eliminate this drawback, and in a two-stage stretching method for polyamide fibers, a saddle-type heater is used in the second stage to simultaneously carry out hot stretching and thermal relaxation treatment. , the second stage stretching ratio is 24.5 to 26.5 log% of the total stretching ratio, and the thermal relaxation rate is 8.0
This is a method for drawing polyamide fibers, characterized in that the polyamide fibers are drawn in an amount of 10.0% to 10.0%.

The second stage drawing ratio DR2 is relative to the total drawing ratio DRT.

Log % (hereinafter referred to as DR ratio) will be explained.

The relationship between DRT, DR1 and DR2 in the two-stage stretching method is as shown in equation 1.

1 set D RT = DR1XDR2 If we take both sides as common logarithms, we get 2 equations.

Equation 2 log DRT= log DR, +log D
R.

The DR ratio in the method of the present invention is defined by three formulas, and there are other ways to express it (such as DR1/DR2).

Type 3 DR ratio (@-100X logDR2/logD
When the RTDR ratio is 24.0% or less and 27% or more, the occurrence of single yarn breakage, yarn breakage, and fuzz increases.

Further, the present invention (thermal relaxation rate) will be explained below.

The draw roller 10 has a roller peripheral speed v1 (m/f+
), and the bobbin 14 is rotating at S (times/minute).

By measuring the traveling speed T (times/min) of the traveler when the bobbin diameter is B), the winding speed of yarn 1 2 (
m7 minutes) can be calculated using 4 formulas.

Equation 4: V2=BπX (S-T) The thermal relaxation rate α(a) can be calculated using Equation 5 from vl and v2.

Formula 5 α=100-100V1/V2 Thermal relaxation treatment area is draw roller 10 and free roller 9
However, the total relaxation area is 1.2 to 3.0 m between the draw roller 10 and the bobbin 14, and the thermal relaxation rate depends on the drawing speed, spindle rotation speed, ring diameter. The yarn winding tension can be controlled by the weight of the traveler, the temperature of the saddle heater 8, the draw roller 10, etc.

If the thermal relaxation rate is small, the dimensional stability will decrease, and if the thermal relaxation rate is high, the dimensional stability will be good, but loop-like defects caused by uneven shrinkage between single yarns will increase, and the winding density of the yarn will decrease. decreases.

The stretching method of the present invention has a thermal relaxation rate in the range of 8.0 to 0%, and when the thermal relaxation rate is 7.5% or less, dimensional stability decreases, and when it is 10.5% or more, loops occur. The number of defects increases and the winding density of the yarn decreases.

Hereinafter, the stretching method of the present invention will be explained based on Examples.

First, the effects of a stretching method in which hot stretching using a saddle type heater and thermal relaxation treatment are performed simultaneously in the second stage of stretching will be explained.

Example 1 The effects of a stretching method in which hot stretching and thermal relaxation treatment are performed simultaneously using a saddle type heater are compared with other conventional stretching methods.

Nylon-6 brand 1260d/210f Drawing speed 25o m/min Spindle rotation speed 4500 times/min Heater filling 185℃ Yarn winding tension 0.12-0.13 g/d ring
8-inch diameter sintered ring stretching method Method A A stretching method using the stretching apparatus shown in FIG.

After completing the first stage of drawing, the yarn 1 is passed through a draw roller 10 and a free roller 9 heated to 150°C.
5.5 turns, 1 in 8 saddle type heaters
It is hot stretched while one side is in contact with the other, and then the draw roller 1
1 on the left side of the saddle type heater 8 between 0 and the free roller 9.
After being brought into contact and thermally relaxed, it is wound up without passing through the draw roller 10.

B method A stretching method using the stretching apparatus shown in FIG.

After completing the first stage of drawing, the yarn 1 is passed through a draw roller 10 and a free roller 9 heated to 150°C.
The winding 1, that is, 11 surfaces are in contact with the saddle-shaped heater 8, and then the draw roller 10 and the separate roller 15 (t
This yarn is wound once, and is then taken up by a draw roller 10 via a yarn guide 11.

The thermal relaxation treatment is performed by a draw roller 10.

C method A stretching method using the stretching apparatus shown in FIG.

After the first stage of drawing of the yarn 1 is completed, the yarn 1 is heated to a box type heater 1.
The 6f roller is wound six times around a draw roller 10 and a separate roller 15 which are in contact with each other and heated to 150°C.
It is wound up from a draw roller 10 via a yarn guide 11.

The thermal relaxation treatment is performed by a draw roller 10.

D method A stretching method using the stretching apparatus shown in FIG.

The stretching method is the same as the above C method, but the draw roller 1
0 is not heated and has no thermal relaxation treatment Saddle type heater 8
The weld length is 400 rran on one side, and the box type heater 1
The suction length of No. 6 is 400 mm.

In addition, in this example, the yarn winding tension was set to 0.12 to 0.
, 13r/d, the traveler weight is adjusted to A method 36
0■, B method and C method 410■, D method 51011IIi
And so.

As is clear from the results in Table 1, method A has dimensional stability due to thermal relaxation treatment using a saddle-type heater (3.
The yarn shrinkage rate after standing for 0 minutes) was better than the thermal relaxation treatment using a heated roller in Method B and Method C.

In addition, to improve heat treatment during stretching using a saddle type heater,
The DRmax of methods A and B (the highest value of DRT at which the number of single filament breakages is 1 spindle or less during drawing of 24 spindles for 1 kg) is approximately 2% higher than the DRmax of methods C and D. By increasing the strength, high strength yarns were obtained in Method A and Method B.

Figure 4 shows the relationship between DR ratio and DRmax,
The vertical axis shows DRmax, and the horizontal axis shows DR ratio (a).

Comparing methods A and B (indicated by A in Figure 4) and methods C and D (indicated by the opening in Figure 4), the DR ratio is 24 to 27.
In the range H, the DRmax of methods A and B is higher than the DRmax of methods C and D, and the DR ratio is 24.5 to 26.
In the range of 5%, the DRmax of methods A and B was higher than the highest value of DRmax of methods C and D.

That is, in methods A and B, the DRmax is large because the heat treatment during stretching is large, but the range in which the DR ratio is good is narrow because the friction between the saddle type heater and the yarn is large.

Table 1 shows the maximum value of DRmax in each of the drawing methods A, B, C, and D, and the performance of the drawn yarn obtained under the condition that DRT is the maximum value of DRmax.

Example 2 In the stretching method O of method A of Example 1, DRT5.40
Stretchability and fuzz were compared between DR ratios of 23.5% to 27.5%.

As is clear from the results in Table 2, when the DR ratio was 24.0% or less and 27.0% or more, single yarn breakage, yarn breakage, and fuzz increased significantly.

Single thread cutting and thread cutting are shown as single thread cutting I and thread cutting (A) during drawing of 5 kg of 240 spindles, and fuzz is shown as the number of fuzz per 100 m of drawn thread.

Note that no significant change was observed in the winding tension of the yarn or the performance of the drawn yarn at the DR ratio within the range of this example.

Example 3 The thermal relaxation rate was 7.0 to 1 using the stretching method A of Example 1 and under the conditions of DRT 5.40 and DR ratio 25.5%.
Dimensional stability, loop defects, and yarn winding density were compared between 1.0% and 1.0%.

The thermal relaxation rate was controlled by the winding tension of the yarn, and the winding tension of the yarn was controlled by the weight of the traveler.

As is clear from the results in Table 3, when the thermal relaxation rate is less than 7.5%, dimensional stability decreases (hot water shrinkage rate increases)1, and when the thermal relaxation rate is more than 10.5%, loop defects increase. In addition, the winding density of the yarn decreased.

Note that the loop defects were expressed as the number of loop defects per 100 m of drawn yarn.

As described above, by the stretching method according to the present invention,
A drawn polyamide yarn having high strength and good dimensional stability can be obtained without reducing drawability or increasing fuzz and loop-like defects.

[Brief explanation of the drawing]

FIG. 1 is a simplified diagram of a stretching device used to carry out the stretching method of the present invention, FIGS. 2 and 3 are simplified diagrams of a stretching device used to implement the conventional stretching method, and FIG. It is a graph showing the relationship between the ratio and D Rrn a x. 1: Yarn, 3 Ni dot roller, 4: Feed roller, 6: Draw roller, 8: Saddle type heater, 9: Free roller, 10 Ni dot roller, 16: Box type heater.

Claims (1)

[Claims] 1 In a method for two-stage drawing of polyamide fibers, 1 and 2
A saddle-type heater is used in each stage to perform hot stretching and thermal relaxation treatment at the same time, and the stretching ratio in the second stage is set to 24.5 to 26 of the total stretching ratio.
, 5 log% i, and thermal relaxation rate of 8.0 to 10.0%.
A method for drawing polyamide fibers.