KR920003133B1 - Manufacturing process of polyamide multi filament yarn - Google Patents

Abstract

In high speed spinning process of polyamide multifilament yarn whose spinning speed is 3500 m/min - 4200 m/min, hot water, whose temperature is 30-50 deg.C above the second transition temperature of the polymer, is sprayed onto the fiber strand before drawing. Then the fiber strand is passed through hot-roller whose temperature is 30-100 deg.C above the second transition temperature of the polymer to be drawn with the drawing rate 80 % more than that of natural drawing, thus making polyamide multifilament yarn.

Description

Manufacturing method of polyamide multifilament yarn

The present invention relates to a method for producing polyamide multifilament yarns by a high-speed spinning method, more specifically, to have a unique texture of polyamide fibers, and does not cause dyed spots and dyed teas with changes over time, and is used as a flat yarn for fabrics. It relates to a method for producing a polyamide multifilament yarn suitable for.

The polyamide fibers of the present invention consist of polycaproamide or copolymerized polyamide having the main component thereof.

Recently, a method of producing polyamides having high molecular chain orientation during the spinning process by high-speed spinning of polyamide is known, and a method of manufacturing a processed yarn using a drawing combustor using the multifilament prepared in this way is about 2,000 m / min. Winding after stretching at a speed, there is an advantage that the productivity can be maximized as compared to a method for producing a flat yarn for fabric or by twisting the drawn yarn to produce a processed yarn.

In addition, when the yarn is manufactured by a high-speed spinning method using polyamide having a very high crystallization rate, crystallization and crystallization of the degree that have undergone the stretching process are compared with those produced by the low-speed spinning method.

However, the microstructure of the polymer crystallized by the high-speed spinning method has a unique crystal structure that is completely different from that of the low-speed spinning method. The microstructure of the polyamide multifilament yarn has a special structure that is different from that of polyester, polyethylene, and polypropylphene. This is because it has polymorphism.

More specifically, when the polyamide fiber is sufficiently conditioned and stretched or heat treated, the pseudo-form is formed when the alignment is performed without sufficient leg time, such as α-type crystal having monoclinic crystal lattice and high-speed spinning. It mainly has a γ-type crystal having a hexagonal crystal lattice.

However, since polyamide multifilament unstretched yarn manufactured by high-speed spinning method has more than 40% of the crystals as γ-type crystals, when water in the air is absorbed, the change over time such as transition of crystal form, post-crystallization and birefringence change is severe. do.

Therefore, in order to remove such a change over time and to produce a polyamide flat yarn with a stable structure, a polyamide flat yarn must be treated with a soft combustor attached with a heating plate. Due to its mechanical properties, the elongation is poor.

The present invention solves the above problems as described in detail below.

The present invention is to produce a non-stretched yarn (γ-type crystal of 40% or more) of polyamide multifilament by a high-speed spinning method of more than 3,000m / min spinning rate 4,500m / min, and then immediately before stretching A high temperature water of 30 ° C. to 50 ° C. above the polymer's secondary transition temperature (Tg ° C.) is injected into the yarn through the nozzle at about 0.1 g / min to 0.2 g / min. It is a method for producing polyamide multifilament yarn which is passed through a heat roller having a high temperature of 30 ° C or more and 100 ° C and thermally drawn at a draw ratio of 80% or more of the natural draw ratio.

In general, unstretched yarns manufactured by high-speed spinning method have high crystallinity and deformation at room temperature on the stress extension curve, thus reducing the natural stretch ratio, that is, the area where molecular chain orientation only occurs without increasing the stress after necking and orienting the molecular chain. As it exhibits a tendency of strain hardening (strain hardening), which is increasingly stressed, the elongation is poor. Therefore, when the hydrothermal treatment is carried out as in the present invention, when the polyamide undrawn yarn is stretched, water 30 ° C. to 50 ° C. higher than the secondary transition temperature of the polymer buried in the yarn increases the fluidity of the molecular chain while acting as a plasticizer for the polymer. Easily stretched and softens the feel of the final product.

In addition, when the polyamide non-stretched yarn is thermally drawn in a polymer and a heat roller 30 to 100 ° C. higher than the secondary transition temperature, the unstable γ-type crystal structure in the polymer is changed into a stable α-type crystal structure, resulting in good drawability. It is possible to produce flawless flat yarns during the post-processing process.

In addition, the yarn manufactured according to the present invention is hot drawn, thus imparting a soft touch to the final product as compared to cold drawn.

The microstructure of the polyamide multifilament yarn manufactured by the present invention was as follows, and the polyamide multifilament yarn produced by the present invention exhibited excellent touch and dyeing characteristics unique to polyamide fibers and was very useful for fabrics. Suited.

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Crystal region (Xc): 0.35 or more

Size of microcrystal of α-form crystal appearing on the equator of diffraction diagram: 35Å-50Å

Ratio (α / γ) of α-type crystal region and γ-type crystal region among all crystal regions: 1.9-3.0

Orientation Function (fc) of α-form Crystals: 0.90 or More

[Examples 1-6 and Comparative Examples 1-3]

Melt spun nylon 6 with a relative viscosity of 2.42 and solidify the spun yarn with a cooling wind of 19 ° C. and 0.45 m / min, and supply emulsion in emulsion at 3,500 m / min and 4,000 m / min. , A nozzle jet that can be wound up at a speed of 4,200m / min, and sprays hot water (temperature = polymer Tg + 30 ℃ ~ Tg + 50 ℃) and hot roller that can perform thermal stretching (temperature = polymer Tg + 30 ° C. to Tg + 100 ° C.) was used to draw at a stretching temperature of Tg + 45 ° C. to Tg + 65 ° C. at a natural draw ratio to prepare a stretch yarn of 70 denia / 24 filaments.

The results are shown in Table 1.

TABLE 1

(x: poor, ○: good, ◎: excellent)

In the embodiment of the present invention, the drawability is good, there are few product defects, but in the comparative example, the drawability is very poor, and bowing and trimming are severe. It was.

Claims (1)

In the stretching of polyamide multifilament unstretched yarn produced by a high-speed spinning method having a spinning speed of 3,500 m / min to 4,200 m / min, hot water having a temperature higher than 30 ° C. to 50 ° C. above the secondary transition temperature of the polymer immediately before stretching. Polyamide multifilament characterized in that it is sprayed at the yarns, and then passed through a heat roller having a temperature higher than 30 ° C. to 100 ° C. above the secondary transition temperature of the polymer to be drawn at a draw ratio of 80% or more of the natural draw ratio. Manufacturing method of the company.