KR0124941B1 - High speed spinning method of polyamide - Google Patents

Abstract

To remarkably reduce the fiber cutting that frequently occurs during the spinning at high speed and drawing process so as to stabilize the process and to enhance productivity, the fatty or aromatic diamine and dicarboxyl acid containing carbon more than 4 or copolymerized polyamide of which component is in a ratio of 0.2~2.0 mol% to caprolactam, composed of one group selected among from the two compounds is used.

Description

High Speed Spinning Method of Polyamide

The present invention relates to a melt spinning method of polyamide, and more particularly, to a method of improving spinning workability by minimizing the occurrence of trimming in the spinning and stretching step during high speed spinning with a spinning speed of 2500 m / min or more.

Melt spinning method is the most commonly used spinning method of polyamide. The melt spinning method is a relatively simple method of heating a polymer to a temperature above the melting point and then extruding, cooling, and solidifying the fiber into chips. It is divided into spinning method and direct spinning method which is directly connected with polymerization process and spinning process.

In addition, in recent years, the spinning speed is gradually increased to improve productivity, the high speed spinning of 2500 ~ 3000m / min or more is widely employed. However, the polymer passed through the spinning nozzle is severely deformed in the stretched region before it solidifies, and as the molecular chains are solidified, they are oriented by the radial tension, and the phase change and the structural form change during the crystallization are induced, causing the trimming. It also adversely affects the workability at the time of stretching. Therefore, the melted yarn has been suppressed by quenching the released sand using cold wind during melt spinning, and the crystallization time until solidification has been suppressed.

However, this method may be effective in low speed spinning, but in the case of high speed spinning, the molecular orientation is caused by the radial tension and crystallization occurs. As the number of envoys increases rapidly, it has been regarded as a task to be solved in this field.

Based on the above facts, the present inventors have continued to investigate the crystallization and molecular orientation behavior of polyamides having high orientation and low crystallization in high-speed spinning, and can suppress crystallization during molecular orientation. As a result of studying the method, the present invention has been completed by recognizing that addition of a specific compound during the preparation of polyamide has a significant effect on stabilizing the trimming during spinning, thereby stabilizing the process and contributing to the improvement of productivity.

That is, the present invention suppresses the crystallization of molecularly oriented yarns by forming heterogeneous bonds in polymer repeating units in the high-speed spinning of polyamides whose main repeating units are pentamethyleneamides. Specifically, caprolactam as a raw material of polyamides is suppressed. In addition, at least one component selected from diamine, dicarboxylic acid, or two mixed components is characterized by using a polyamide copolymerized with 0.2 to 2.0 mol%.

As the diamine or dicarboxylic acid to be introduced in the present invention, an aliphatic or aromatic compound having 4 or more carbon atoms may be used, and an aromatic compound having 8 or more carbon atoms is more effective. The timing of addition of the diamine and the dicarboxylic acid may be possible at any stage before the polyamide polymerization reaction is completed, but it is generally preferred to melt with caprolactam and enter the polymerized coal.

The reason for limiting the mole percent of at least one component selected from diamine, dicarboxylic acid, or two mixed components copolymerized in the present invention is 0.2 mol% or less, so that the effect of inhibiting crystallization in molecular orientation according to the present invention is If it is not obtained and is 2.0 mol% or more, the color of the polyamide deteriorates, and the melting point decrease of the polymer becomes large, so that it is not practical, it is preferable to use it in the range of 0.2-2.0 mol% with respect to the caprolactam used as a raw material of polyamide.

The medicaments used in the present invention include hexamethylenediamine, m-xylenediamine, and the like as diamines, and adipic acid, sebacic acid, maleic acid, terephthalic acid, isophthalic acid, and the like as the dicarboxylic acid may be aliphatic. Both diamines and dicarboxylic acids, both aromatic and aromatic, may be used.

Copolymerized polyamides of the present invention can be obtained in the same manner as in conventional polyamide spinning by adding various additives, for example, anti-inflammatory agents such as titanium oxides, dyeing agents, flame retardants, heat-resistant agents, light-resistant agents, etc. to obtain characteristic materials. In accordance with the present invention, the spinning thread during the spinning and stretching process is significantly reduced during the high-speed spinning with a spinning speed of 2500 m / min or more, so that the process is stable and productivity is greatly improved.

For the purpose of illustrating the present invention in detail with reference to the following examples, of course, the embodiments do not limit the invention.

Example 1-5, Comparative Examples 1 and 2

As shown in Table 1, polyamide (relative viscosity 2.50-2.60) containing diamine and dicarboxylic acid was spun through a spinning nozzle at a spinning temperature of 280 ° C. and a discharge amount of 40 g / min. Cooling while blowing to min to give an emulsion, then wound at a speed of 3,000m / min to obtain a non-drawn yarn of 70/34 (D / fil), which was cold drawn at a draw ratio of 1.55. Table 1 shows the characteristics such as the rate of trimming at this time.

TABLE 1

* Number of trimmings is the number of trimmings generated for the total number of dopings (333 times) based on 1,000 hours.

* F / B% is the percentage of no-dope doping produced in unit time.

* In the case of Comparative Example 2, it was confirmed that the polyamide was not practical due to the deterioration of the color (YI value increase) and the lowering of the melting point.

Example 6-8, Comparative Examples 3 and 4

As shown in Table 2, polyamide (relative viscosity 2.60-2.70) containing a compound of diamine and dicarboxylic acid was spun through a spinning nozzle at a spinning temperature of 280 ° C. and a discharge amount of 40 g / min. Cooling while blowing at m / min to give an emulsion, then wound at a rate of 3,000 m / min to obtain a non-drawn yarn of 70/34 (D / fil), which was cold drawn to a draw ratio of 1.55. Table 2 shows characteristics such as the incidence of trimming at this time.

TABLE 2

* HMDA: hexamethyldiamine

[Example 9-11, Comparative Example 5]

As shown in Table 3, polyamide (relative viscosity 2.50-2.70) containing diamine, dicarboxylic acid or two compounds thereof was spun through a spinning nozzle at a spinning temperature of 280 ° C. and a discharge amount of 38 g / min, and cooled at 20 ° C. Air was blown while blowing at a wind speed of 0.6 m / min to impart an emulsion and then wound up at a speed of 5,000 m / min. Table 3 shows the incidence of trimming at this time.

TABLE 3

Claims (2)

In the high-speed spinning of polyamide whose main repeating unit is pentamethyleneamide at a spinning speed of 2500 m / min or more, at least selected from aliphatic or aromatic diamines having 4 or more carbon atoms, dicarboxylic acids or two compounds thereof in addition to caprolactam A high-speed spinning method of a polyamide, characterized in that the polyamide copolymerized at 0.2 to 2.0 mol% with respect to caprolactam is used. The method of claim 1, wherein the diamine is hexamethylenediamine, m-xylenediamine and dicarboxylic acid is adipic acid, sebacic acid, maleic acid, terephthalic acid, isophthalic acid.