KR0180825B1 - The manufacture method of the midair fiber to the superiority stability nature - Google Patents

Abstract

The present invention relates to a hollow fiber manufacturing method having excellent morphological stability of high hollow ratio of more than 30% of the hollow ratio, the angle of bending the edge portion of the curved slit (slit) toward the hollow portion is in the range of 60 ~ 160 ° and the slit length By using spinnerets arranged in a circular or four-leaf clover shape with a plurality of curved slits having 0.1 to 26% of the length of the curved part, the hollow fiber prevents ring opening or yarn distortion and makes hollow fiber with excellent workability. will be.

Description

Hollow fiber manufacturing method with excellent shape stability

(A)-(d) of FIG. 1 is a cross-sectional view of the spinneret used for this invention.

(A) to (d) of Figure 2 is a cross-sectional view of the hollow fiber made of the spinneret above.

3 is a cross-sectional view of the spinneret used in Comparative Examples (a) to (c).

Figure 4 (a) ~ (c) is a cross-sectional view of the hollow fiber made of the detention used in the comparative example.

The present invention relates to a method for producing a high porosity hollow fiber excellent in shape stability.

Fibers with high porosity generally contain a large number of air layers and thus have a low specific gravity and excellent heat retention. Therefore, it has a light and warm feeling and has excellent characteristics, and is widely used in thermal insulation clothes, duvets, thermal blankets, sleeping bags, etc., but the hollow yarns that have been developed up to now have a pressure imbalance at the top of the spinneret during spinning, or a polymer melt spun In the process of cooling, the yarn is opened by the air vortex or the hollow fiber is opened when repeated use, so that the air layer is lost, there is a defect in repulsion, sublimeness, heat retention and dyeing.

Conventionally, the method of increasing the hollow ratio of the hollow fiber is to use a spinneret in which two or more curved slits are arranged in a circular shape, the diameter of the mold, the slit width, the length between the curved slits and the slits, and the viscosity of the polymer melt. It is known how to adjust the discharge amount, the cooling method of the discharge thread, but this method alone could not completely solve the problem of the welding point (falling welding point) fall could not achieve the desired results.

Accordingly, an object of the present invention is to prevent the ring opening during spinning and to obtain a high-porosity hollow fiber excellent in resilience, heat retention, bending rigidity and durability even in repeated use in the production of hollow fiber having a high porosity.

The present invention uses a spinneret having a uniform width and having a spinneret having two or more curved slits arranged in a circular or four-leaf clover shape in which the edges of the curved slits are bent toward the hollow part (see FIG. 1). It is to produce a high hollow fiber hollow fiber having excellent morphological stability, in general, when the hollow fiber spinning of more than 30% of the hollow ratio is a lot of cases, such as ring opening, distortion of the yarn, poor workability, etc.

In the present invention, in the case of the detention having two curved slits (Fig. 1 (a) and (b)) and the detention having three curved slits (Fig. 1 (c)), the four-leaf clover type curved slit detention ( In the case of (d) of FIG. 1 and four or more curved slits, the angles and lengths of the curved portions are adjusted differently. This is because in case of general slit type detention, the die swelling when leaving the spinneret has a large difference in the maximum die swelling in the slit length direction and the slit width direction according to the slit width and the slit length ratio. The length between the slits should be adjusted accordingly. Typical maximum die swelling ratio is shown in Table 1 below.

L) Length of detention slit

W: width of the slit

Here, as the number of curved slits increases, die swelling in the longitudinal direction increases, so the length between the slits and the slits should be increased. However, when the length of the slit and the slit becomes longer, it is easy to deviate at the junction. In addition, the ratio of the swelling ratio in the width direction to the slit edge at the center of the slit increases as the number of curved slits increases, so the thickness difference between the joint point of the yarn and the center of the slit becomes relatively large. The junction point is thin and easy to open (see FIGS. 3 and 4).

Therefore, the present invention was made to solve the problems as described above, using a curved slit bent toward the hollow portion near the edge of the curved slit, so that the length of the bent portion is 0.1 to 26% with respect to the slit length and curved By making the angle of the edge portion of the slits bent toward the hollow portion in the range of 60 to 160 °, it was possible to produce a hollow fiber having a high hollow ratio with excellent shape stability. If the length of the bent portion is less than 0.1% with respect to the slit length, the degree of inclination is small, so that the hollow ratio is lowered, the ring opening percentage is increased, and the spinning workability is also lowered. In addition, when it is larger than 26%, the ring-opening percentage and the swelling percentage are high, and the spinnability is also poor. The length of the bent portion with respect to the slit length is more preferably 0.1-10% for two curved slits, 0.1-15% for three, and 0.1-20% for four.

And in each case bent angle is suitable 60 ~ 160˚. If it is less than 60˚, the hollow ratio generally decreases, and the ring-opening percentage before and after weaving increases. In case of exceeding 160˚, the hollow ratio increases, but the ring-opening percentage is high and the spinability is poor.

As shown in (d) of FIG. 1, the slit with a small curvature is opened more easily than the curved slits arranged in a circular shape. This is because the curvature of the spinning yarn has a tendency to be unfolded due to the smaller curvature than the circular slit. This is because the points are easily shifted from each other.

Therefore, in the case of four-leaf clover-shaped curved slit with small curvature, the length of the bent portion with respect to the slit length should be about 30-40% larger than the curved slit of the circular arrangement.

Hereinafter, the present invention will be described in detail with reference to the following Examples.

EXAMPLES 1-4

6.7 × 10 weight average injection quantity prepared by a conventional method Melt-extruded phosphorus polyethylene terephthalate polymer to a temperature of 280 ~ 290 ℃ and spinning 24 spinning holes 34.2g per minute through the four spinnerets shown in Figure 1 under the following conditions, the speed of the first drawing roller Was 1,260 m / min, and the speed | rate of a 2nd extending roller was spun and stretched at 4,100 m / min, and the stretched yarn of 75 denier was obtained.

Table 2 shows the percentages of the slit width at the jointing point for the hollow rate and the ring opening percentage in four detentions, the spinability, and the average slit width of the hollow yarns for the drawn yarns prepared under the above conditions.

Furthermore, after sizing this, the fabric was fabricated with the same structure and the same inclined density using a warp yarn and dyed under the same conditions to obtain a desired fabric.

Table 3 shows the results of measuring the ring-opening degree, the characteristics of the fabric, the weaving workability, and the shape stability of the hollow fiber after a certain period of time (ASTM D3885) using the wear strength test apparatus (expanded film method).

[Comparative Examples 1 to 3]

Except that three spinnerets were used in FIG. 3, the results were shown in Tables 2 and 3 under the same conditions as those in Examples 1 to 4.

[Comparative Examples 4-7]

The results are shown in Tables 2 and 3 in the same manner as in Examples 1 to 4, except that the lengths, angles, and spinnerets of the curved portions with respect to the slit lengths were as shown in Table 2.

In Table 2, the hollow ratio, ring opening percentage, and swelling fraction are obtained by the following equation.

Compressive elasticity: According to KS K 2617 (Cotton Duvet Cotton Testing Method), the sample was measured as having a size of 20 × 20 cm and the compressibility and recovery rate were obtained.

Volume recovery rate by drying: Samples were measured according to KS K 2617 (cotton duvet cotton test method) in a size of 20 × 20 cm.

Insulation rate: According to KS K 0466 and KS K 0506 (constant temperature method), the sample was measured as the size of 20x20cm (thickness about 3cm).

Claims (3)

In the radial stretching of hollow fibers, a spinneret having a spinneret having two or more curved slits arranged in a circular or four-leaf clover shape in which the edge subgroup of the curved slits is bent toward the hollow part is used. Method for producing a hollow fiber excellent in shape stability, characterized in that the angle and length of the bent portion is adjusted differently. The method of claim 1, wherein an angle at which the edge portion of the curved slit is bent toward the hollow portion is within a range of 60 to 160 degrees. The method for producing hollow fiber having excellent shape stability according to claim 1, wherein the length of the bent portion is 0.1 to 26% with respect to the slit length.