JPS6015734B2 - Method for manufacturing polyamide crimped yarn - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing polyamide wound warp yarns, and aims to provide a method for manufacturing wound warp yarns having a high degree of curl fastness by drawing friction false twisting. .

In recent years, the friction false twisting method, which has a faster processing speed and higher production efficiency, has become the mainstream method for producing polyamide crimped yarn.

Also, considering the manufacturing cost including shortening of the manufacturing process,
It is advantageous to employ a drawn false twisting method in which the undrawn yarn or POY is processed simultaneously or sequentially with drawing. That is, it is advantageous to perform friction false twisting simultaneously or sequentially with stretching. However, this method has the drawback that since processing is performed at high speed, sufficient setting time with a heater cannot be taken, and the crimp fastness of the crimped yarn obtained is generally low. For this reason, the actual situation is that the uses of wound warp threads are naturally limited. In order to avoid this, the heater length must be made extremely long or the machining speed must be reduced. Needless to say, there are certain limits to the method of increasing the length of the heater due to equipment space and workability. Furthermore, if the processing speed is lowered, it is difficult to avoid a decrease in production efficiency. If the same equipment is used in the stretch friction false twisting method of the present invention, a product with higher crimp fastness can be obtained, which is better than the conventional crimp method. It is an object of the present invention to provide a method for producing a polyamide crimped yarn that can be processed at a higher speed even with the same equipment when robustness is sufficient.

As a result of repeated studies based on these objectives, the inventors of the present invention found that
In drawing friction false twisting processing of polyamide yarn, the moisture content of the supplied undrawn yarn is dominant in the crimp fastness, and it is possible to stabilize the crimp fastness by using the supplied drawn yarn with such a low moisture content. In order to carry out production, it was concluded that the birefringence index of the supplied undrawn yarn must be within a certain range, and this led to the invention.

That is, in the present invention, polyamide polymer and undrawn yarn are melt-spun so that the birefringence index is 35 x 10-3 or more, and the moisture content of the wound yarn is always 3.0% or less (preferably 1.0%). ~2.
5%) and supplied to the processing process at a rate of 300 machines/mi.
This is a method for producing a polyamide wound warp yarn, which is characterized by performing a stretching friction pre-combustion process at a processing speed of n or more.

Nylon 6 as a polyamide polymer applied to the present invention
, nylon 66, etc., or a copolymer containing these as main components.

These polymers may contain some additives such as matting agents and heat-resistant agents, or may be in the form of composite filaments using one or both of these polyamide polymers. Any material containing a polyamide polymer is preferably applied. In the present invention, it is necessary to first melt and discharge the polyamide polymer, and then wind up the yarn at a high speed so that the undrawn yarn to be wound has a rear refractive index of 35 x 10-3 or more. The birefringence of the thread is 35×10-3
If the moisture content of the wound yarn is less than 3.0%, it is difficult to maintain the moisture content of the wound yarn at 3.0% or more. The birefringence of undrawn yarn obtained at the normal paper yarn speed of around 1000/arm is usually 1.
5xlo-3 to 20x10-3, but when a filament with such a low birefringence range is wound with a moisture content of 3.5%, the filament will elongate during or after winding. However, the package may collapse, making stable winding difficult. That is, although the standard humidity condition in Japan is around 60%, the equilibrium moisture content of polyamide polymer under such humidity is 4.0 to 4.5% or more, so After winding, the filament absorbs moisture and stretches. For this reason, when melt-spinning polyamide polymers, it is common to set the moisture content of the wound yarn to 4.5% or more, and also to stretch and false twist the undrawn yarn. The moisture content is usually 4.5% or more. However, the birefringence index of undrawn yarn is 35
-10-3 or higher, it is possible to supply a stable package to the processing process without stretching even if the moisture content changes during subsequent moisture absorption and desorption, and it also has excellent durability over time. In the present invention, the birefringence is 3.
A common method for threading is to thread at a high speed of 3000 skins/min or more, such as at a thread winding speed of 3000 skins/min or higher.

With this high-speed paper yarn method, it is also possible to lower the moisture content of the wound yarn compared to conventional low-speed yarn removal, which means that there is almost no moisture absorption during winding, and the amount of moisture added by an oiling device etc. can be reduced. By controlling the moisture content of the wound yarn, it is possible to arbitrarily control the moisture content of the wound yarn. In the present invention, the moisture content of the wound yarn means the average value for the entire package, and the package is divided into three parts: the outer layer, the middle layer, and the inner layer. The moisture percentage shall be defined as the average of the moisture percentages sampled.

In the present invention, it is necessary to maintain the moisture content of the wound yarn as defined above at 3.0% or less, preferably 1.0 to 2.5%, during the stretching and friction false twisting process. It is.

If undrawn yarn with a moisture content of more than 3.0% is supplied and subjected to drawing friction false twisting, the longitudinal winding fastness deteriorates, which is not preferable. When the moisture content is 3.0% or less, especially 1.0 to 2.5%, it becomes possible to raise the processing temperature compared to the conventional case of supplying undrawn yarn with a high moisture content, and it also makes it possible to reduce crimping. Robustness is also improved. The method of the present invention is effective when the above-mentioned wound yarn is supplied to the processing process and subjected to stretching friction false twisting at a relatively high speed, and the processing speed is 300 threads or more, preferably 500 threads per thread. More preferably, the higher the speed of machining at 700 mm or higher, the greater the effect.
At a machining speed of about 250 mm, the present invention has almost no effect.

Furthermore, the stretch friction false twisting process may be either an "in-draw method" in which false twisting is performed simultaneously with stretching, or an "out-draw method" in which false-twisting is performed subsequent to stretching;
The friction false twisting means may be either an external type or an internal type.

Although the stretching ratio varies depending on the after-refractive index of the undrawn yarn, it is generally preferred to be about 1.05 to 1.5 times, and the processing (heater) temperature is generally about 150 to 200 q○. Next, examples of the present invention will be described in detail.

Both CR and CR' in the example are values indicating the crimp characteristics of the crimped yarn, and are determined as follows. CR: Stretch recovery rate
Value measured in accordance with JIS standard LIO90. After winding a skein with a specified frame circumference under constant tension to a specified length in water at room temperature, suspending the initial cart and constant load and leaving it for 2 minutes, the final length is determined. Calculate the length from the length after removing the load and leaving it for 2 minutes using the following formula.

CR (%) = 4 Yen life Soak, remove from boiling water and dry naturally for 2 hours, removing the first layer.

Then, it is calculated by the following formula from the initial load and the length after hanging the constant load in the air and leaving it for 2 minutes, and the length after leaving it for 2 minutes, excluding the constant load, 2'.

CR (%) = Era San 2 x ·oo The CR and CR' values of the obtained solid striped yarn were as shown in the following table.

EXAMPLE A polyamide polymer (nylon 6) was melted and discharged from a nozzle having 10 holes, and spun at a weaving speed of 1.000 mm/bar {b) of a weaving speed of 3.800 mm/bar.

At this time, the discharge amount was adjusted so that the denier after processing was 40 denier. Also, adjust the rotation speed of each oiling roller to adjust the moisture content of the package.
0% (o}3.0% to 4.5%. The obtained filament Δn and package stability were as shown in the following table. Comparative example 'a} i),'
a}-{. ), packages made of filaments with low birefringence (△n) have almost 100% birefringence during winding.
% collapse occurred and stable winding was impossible. Table 1: Spinning stability: Package stability during 10 rolls of 6k9, Number of windings: Stable class: (a-W, {bl-'i},
{o--N was supplied to the stretching false twisting process, and the sample 'a} was stretched 3.1 times, and the sample 'b- was stretched 1.15 times.
After stretching to double its original size, it was continuously subjected to friction false twisting.

The draw ratio (outdraw ratio) and friction false twisting processing main conditions at this time are as follows, and the CR and C of the obtained crimped yarn are as follows.
R was as shown in Table 2. Stretching ratio x Stretch rate during processing 'a' 2.910 x 1.035 (b} 1.156 x 1.043 Processing speed 700m/Skin heater length 2 skins VR/VY
2.0 heater temperature
170, 180, 185, 190 Table 2 Crimp characteristics From these results, the results obtained when the moisture content of the package is 4.5% as in the comparative example 'a) day, 'b} day. The crimp fastness of the wound warp yarns is as shown in Example 'b--'.

) The moisture content of the package was lower than that of the crimped yarn, which had a moisture content of 2.0% and 3.0%. In this way, in the drawing friction calcification process of undrawn polyamide yarn, the polyamide polymer is made into a high-speed yarn such that the undrawn yarn birefringence is 35 x 10-3 or more, and then the moisture content of the wound yarn is reduced. A crimped yarn having a high degree of crimp fastness can be obtained by supplying the yarn to the processing step while maintaining the concentration at 3.0% or less and subjecting it to drawing friction false twisting.

Claims (1)

[Claims] 1. Birefringence of undrawn polyamide polymer yarn is 35×1
Melt-spun the yarn so that the moisture content is 0^-^3 or more, and supplying it to the processing process while maintaining the moisture content of the wound yarn at 3.0% or less,
A method for producing a polyamide crimped yarn, which comprises stretching and frictionally false twisting the yarn at a processing speed of 300 m/min or more. 2. The method for producing a polyamide crimped yarn according to claim 1, wherein the wound yarn is supplied to the processing step while the moisture content of the wound yarn is always maintained at 1.0 to 2.5%.