KR20010064270A - A composite fiber having an excellent spinning properties - Google Patents

Abstract

PURPOSE: Provided is a conjugated fiber having excellent spinning workability owing to covering peripheral surface with polyethylene terephthalate ingredient and uniform physical property when a polyamide super-fine fiber is manufactured. CONSTITUTION: The structure of the conjugated fiber is characterized by: arranging polyethylene terephthalate segment(A) and polyamide segment(B) from the center to the circumference in all directions in turns; and covering the peripheral surface with the polyethylene terephthalate segment(A). A maximum diameter(R) of the conjugated fiber is at least twice as large as the longest length(L) of the polyamide segment(B). The conjugated fiber is comprised of 50-85wt.% of the polyamide ingredient and 50-15wt.% of the polyethylene terephthalate ingredient.

Description

A composite fiber having an excellent spinning properties

The present invention is excellent in spinning operation, that is, it is not affected by the temperature and humidity during spinning, and relates to a composite fiber in which the physical properties of the ultrafine fibers are uniform when preparing polyamide microfibers by sea component elution.

Polyamide fiber is one of the fibers particularly affected by moisture. When spinning a polyamide-based fiber, the moisture content should not be kept below an appropriate level like polyethylene terephthalate fiber, but should be kept within an appropriate range. When the moisture content is insufficient, the molecular weight during spinning tends to be excessively large, yellowing may occur due to a small amount of oxygen, and the degree of gel formation in the molten state may vary depending on the moisture content.

Therefore, in order to maintain a constant hygroscopic condition, the polyamide long fiber being wound should be adjusted to the temperature and humidity conditions of the winding room to a temperature of 20 ° C. to 25 ° C. and a relative humidity of 50% or less. Outside the above range, the degree of aging between the inside and outside of the wound polyamide package is different, but the degree of swelling is different, and it is difficult to obtain uniform quality.

In the polyamide-based fiber spinning process, the polyamide-based polymer melt transferred to the spinning block passes through a filter and is released into the air through the spinneret to form fibers. The released fibers solidify as they pass through the cooling zone, where the temperature of the cooling air is very closely related to the physical properties of the fibers. The crystallization rate of polyamide-based fiber is very fast, and it crystallizes during spinning. At this time, the freezing point is changed according to the temperature of cooling air, and thus the temperature at which crystallization occurs is changed, and thus the size and density of crystals formed in the fiber are changed. .

In the case of fast spinning yarns such as high-orientation yarns, the crystallization rate during spinning is fast, and the fiber after spinning has a sufficiently stable structure, while the spinning speed is in the range of 500 ~ 4000m / min when it is subjected to general spinning and stretching processes such as partial orientation yarn or non-orientation yarn. Therefore, sufficient structural expression is not achieved during radiation.

In this case, the wound yarn, unlike polyethylene terephthalate-based fibers, can absorb water in the air and swell, causing significant obstacles to the process. In order to prevent this, a method of expressing a stable structure at the same time as water is supplied in advance by adding water vapor in the solidification process is performed, but instability is amplified because the process is sensitive.

Therefore, polyamide-based long fibers are very sensitive to temperature and humidity conditions, and management and air conditioning costs are very complicated and require careful attention compared to general polyethylene terephthalate production conditions, and general air conditioning conditions such as polyethylene terephthalate spinning and air conditioning conditions In production it is almost impossible.

In general, polyamide fine fibers (microfine fibers) have a single yarn fineness of 0.5 denier or less, which can satisfy the appearance, feel, and physical properties of natural leather during post-processing, making them a popular alternative to natural leather. It is used a lot in. The manufacturing method of the fineness fibers is divided into the steel forming method and the forming method by the viscosity difference according to the island component, that is, the pipel forming method. The former is a method of forcibly injecting and forming a dispersed phase component (hereinafter referred to as a "island component") into a continuous phase component (hereinafter referred to as "sea component") in the stage immediately before detention. It is a method of mixing several times in the step before detention so that a component with high viscosity becomes a island component.

Other incompatible bicomponent polymers (e.g. polyamide and polyethylene terephthalate, etc.) may be combined at the stage immediately before detention and then finely divided by physicochemical partitioning. In addition, it can be produced by the direct spinning method through high-speed spinning and polymer modification, but poor spinning stability and poor operation.

As a conventional technique for producing polyamide fine fine fibers, a method using a polyamide polymer as a island component and a polyethylene or polyethylene terephthalate having a melt index (MI) of 10 to 40 as a sea component is known. However, as shown in Fig. 2, the surface of the composite fiber prepared by the above method is exposed to a large amount of polyamide-based island component having a high weight ratio and a high number of fragments between the polyethylene terephthalate sea component having a low weight ratio.

As described above, polyamide-based fibers are sensitive to temperature and humidity, and yarns have a characteristic of varying maturity and physical properties depending on temperature and humidity conditions. This is because polyamide fiber has strong moisture hygroscopicity and swelling is outstanding, and when it is out of a certain range of temperature and humidity range, different levels of swell between drum inner and outer layers due to difference of moisture absorption rate of polyamide fiber in the composite fiber being wound. The ring phenomenon occurs and the whole yarn drum layer is collapsed, which makes it impossible to dissolve in terms of productivity, and the physical properties are also unstable.

The present invention is to solve the problems of the prior art described above is not sensitive to the temperature and humidity during spinning is excellent in spinning operation and to provide a composite fiber having their uniform physical properties in the production of polyamide microfibers. When the polyethylene terephthalate segment, which is a sea component of the composite fiber of the present invention, is eluted in a later step, it becomes a polyamide microfiber having uniform physical properties.

1 is an enlarged cross-sectional view of the present invention composite fiber.

Figure 2 is an enlarged cross-sectional view of the conventional composite fiber.

※ Code explanation for main part of drawing

A: polyethylene terephthalate segment

B: polyamide segment

R: Maximum diameter of composite fiber

L: longest length of polyamide segment

The present invention is used in the production of polyamide ultrafine fibers with uniform physical properties, and relates to a composite fiber having excellent spinning operation properties. More specifically, in the present invention, the polyethylene terephthalate segment (A) and the polyamide segment (B) are arranged radially alternately from the center of the fiber cross section to the outer circumference, and the outer peripheral surface of the fiber cross section is wrapped by the polyethylene terephthalate segment (A). It relates to a composite fiber excellent in spinning operation, characterized in that it has an aftershock core sheath type structure.

Hereinafter, the present invention will be described in detail.

First, in the composite fiber of the present invention, the polyethylene terephthalate segment (A), which is a sea component (elution component), and the polyamide segment (B), which is a fiber forming component, are alternately arranged radially from the center of the fiber cross-section as shown in FIG. have. In addition, the outer circumferential surface of the fiber cross section is surrounded by the polyethylene terephthalate segment (A) to have a deep sheath structure.

As a result, the polyamide segment (B) having a high weight ratio and a large number of segments can be prevented from protruding between the polyethylene terephthalate segment (A) having a low weight ratio and being exposed to the outside. In other words, polyamide segments (B), which are sensitive to the temperature and humidity, may lower the operability and make the yarn material uneven, and thus cannot come into contact with the temperature and humidity, thereby greatly improving the spinning operation of the composite fiber. Also becomes uniform.

The composite fiber of the present invention is preferably composed of 50 to 85% by weight of the polyamide component and 50 to 15% by weight of the polyethylene terephthalate component. If the polyethylene terephthalate component is less than 15% by weight, the polyamide component may be exposed to the yarn surface, resulting in poor operation and yarn properties. If the polyethylene terephthalate component is more than 50% by weight, the elasticity may be excessively excessive and the density may be insufficient. There is a possibility that post-processability may decrease.

As the polyamide component, polyamide 6, polyamide 4,6 or polyamide 6,6 having excellent fiber forming ability can be used. The maximum diameter (R) of the composite fiber of the present invention is preferably at least two times greater than the longest length (L) of the polyamide segment to improve the radioactivity.

The composite fiber of the present invention can be produced by a conventional composite spinning device. In the composite fiber of the present invention, after weaving a knitted fabric and then removing the polyethylene terephthalate segments, which are eluted from the composite fiber, by the process of reducing alkali, only the polyamide microfiber remains on the knitted fabric. Subsequently, the woven and knitted fabric can be dyed and processed in a conventional manner to be used as a garment fabric.

In the present invention, the operability and various physical properties of the composite fiber are measured (evaluated) as follows.

Strength and elongation

Measure 5 times per sample with Instron 10 times and average these measurements.

Mass change rate

With the Worster Value, measure the mass and change of the sample for 3 minutes at a speed of 25 m / min. Do this ten times to average the measured values.

· Extended workability (%)

The total number of drums produced in 15 days and the normal drum number of which is 18 kg are obtained by substituting the following equation.

Unstretched Operability (%) = × 100

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited only to the following examples.

Example 1

65% by weight of polyamide 6 and 35% by weight of polyethylene terephthalate were spun at a combined spinning device at a spinning temperature of 265 ° C. and a spinning speed of 1,200 m / min to have a cross-sectional shape (R = 2.3L) as shown in FIG. 1. A fiber non-drawn yarn is produced. The unstretched yarn is drawn at a drawing temperature of 70 ° C., a heat extension temperature of 130 ° C., a draw ratio of 3.0 times, and a drawing speed of 800 m / min to prepare a drawn yarn of 75 denier / 24 filaments. At the time of spinning and stretching, the air conditioning temperature was 28 ° C. and the relative humidity was 70%. Table 1 shows the results of evaluating the properties of the drawn yarn and the operation of the undrawn yarn.

Example 2

85% by weight of polyamide 6 and 15% by weight of polyethylene terephthalate were spun at a combined spinning device at a spinning temperature of 265 ° C. and a spinning speed of 1,200 m / min to have a cross-sectional shape (R = 2.3L) as shown in FIG. 1. A fiber non-drawn yarn is produced. The unstretched yarn is drawn at a drawing temperature of 70 ° C., a heat extension temperature of 130 ° C., a draw ratio of 3.0 times, and a drawing speed of 800 m / min to prepare a drawn yarn of 75 denier / 24 filaments. At the time of spinning and stretching, the air conditioning temperature was 28 ° C. and the relative humidity was 70%. Table 1 shows the results of evaluating the properties of the drawn yarn and the operation of the undrawn yarn.

Comparative Example 1

65% by weight of polyamide 6 and 35% by weight of polyethylene terephthalate were combined and spun in a composite spinning device at a spinning temperature of 265 ° C. and a spinning speed of 1,200 m / min to prepare a composite fiber non-drawn yarn having a cross-sectional shape as shown in FIG. 2. . The unstretched yarn is drawn at a drawing temperature of 70 ° C., a heat extension temperature of 130 ° C., a draw ratio of 3.0 times, and a drawing speed of 800 m / min to prepare a drawn yarn of 75 denier / 24 filaments. When spinning and stretching, the air conditioning temperature was 28 ° C. and the relative humidity was 70%. Table 1 shows the results of evaluating the properties of the drawn yarn and the operation of the undrawn yarn.

Comparative Example 2

Polyamide 6 alone was spun at a spinning speed of 1,200 m / min at a spinning temperature of 265 ° C. to produce polyamide unstretched yarn, which was stretched at a draw ratio of 3.0 times and a drawing speed of 800 m / min to produce 75 denier / 24 filaments. Polyamide stretched yarn is produced. The results of evaluating the properties and operability of the drawn yarn are shown in Table 1.

Physical property and operability division Denier Elongation (%) Strength (g / d) Mass variation Non-Extended Industries (%) Average Deviation Average Deviation Average Deviation Example 1 75.3 ± 2.1 35 ± 1.2 3.62 ± 0.12 0.86 96.3 Example 2 74.9 ± 1.9 32 ± 3.6 3.85 ± 0.21 0.91 98.5 Comparative Example 1 73.6 ± 4.5 19 ± 5.0 1.95 ± 0.39 2.35 53.7 Comparative Example 2 76.1 ± 2.3 41 ± 3.8 4.05 ± 0.43 1.35 28.3

Since the outer circumferential surface of the composite fiber of the present invention is wrapped with a polyethylene terephthalate component to minimize the influence of the temperature and humidity during spinning, the spinning operation is very excellent, and the physical properties of the polyamide microfiber are uniform.

Claims (3)

The polyethylene terephthalate segment (A) and the polyamide segment (B) are radially arranged alternately from the center of the fiber cross section to the outer circumference, and the outer circumferential surface of the fiber cross section has a pontic structure surrounded by the polyethylene terephthalate segment (A). Composite fiber excellent in spinning operation. The composite fiber with excellent spinning operation property according to Claim 1, wherein the maximum diameter (R) of the composite fiber is at least twice as long as the longest length (L) of the polyamide segment. The composite fiber having excellent spinning operation property according to claim 1, wherein the composite fiber comprises 50 to 85% by weight of polyamide component and 50 to 15% by weight of polyethylene terephthalate component.