WO2022194116A1

WO2022194116A1 - Composite fiber and preparation method therefor

Info

Publication number: WO2022194116A1
Application number: PCT/CN2022/080803
Authority: WO
Inventors: 徐青; 赵锁林
Original assignee: 东丽纤维研究所（中国）有限公司
Priority date: 2021-03-16
Filing date: 2022-03-15
Publication date: 2022-09-22
Also published as: CN116685728A; TW202300739A

Abstract

A composite fiber and a preparation method therefor. The composite fiber is formed by composite spinning of a polymer A and a polymer B; the composite fiber contains 5-50 wt% of a polyether structural unit; a crimp number A of the composite fiber after being treated in boiling water for 30 minutes and dried is 10-30 crimp/2.5 cm; and a crimp number B of the dried composite fiber after being immersed in softened water at 20°C for one minute and then wiping the surface moisture is 0-50% of the crimp number A. The composite fiber has good crimp performance and moisture absorption/desorption automatic stretching/shrinking characteristics, so that a fabric prepared from the fiber has good breathability.

Description

Composite fiber and preparation method thereof

technical field

The invention relates to a composite fiber and a preparation method thereof, in particular to a composite fiber formed by two kinds of polymers with different contents of polyether structural units.

Background technique

Polyester and polyamide fibers, as traditional chemical fibers, have a wide range of applications, ranging from clothing to industrial products such as fishing nets, filter cloths, cables, tires and parachute cloth. Polyester and polyamide fibers can be used alone or mixed with other natural fibers or chemical synthetic fibers to make fabrics. The resulting fabric has the characteristics of smooth hand, strong durability and moderate price. As people's demand for wearing comfort continues to increase, more fibers with special functions are gradually replacing traditional polyester fibers and polyamide fibers. Among them, fabrics made from fibers with moisture absorption and release self-stretching properties have great demand in the field of sportswear due to their good moisture absorption and quick-drying properties, elasticity and drapability.

In previous patents, research on such fibers was also involved. For example, Chinese patent CN1809657A discloses a kind of polyetherester elastic fiber, which is composed of copolymerized specific organic sulfonic acid metal salt, with polybutylene terephthalate as the hard segment and polyoxyethylene glycol as the soft segment Elastane fibers of polyetherester elastomer. Since the polyetherester elastic fiber has good hygroscopicity, it can reversibly expand and contract by absorbing and releasing water. Although the patent discloses that the water-absorbing elongation of the fibers is 10% or more, the water-absorbing elongation of the fibers can only be at most 25.2% due to the poor crimpability of the individual filaments (Example 1).

In addition, Chinese patent CN110295405A also discloses a hygroscopic elongation composite fiber, the cross-sectional shape is a sun-moon parallel type or an eccentric core-sheath type, and contains a polyamide component and a polyolefin component. The composite fiber increases the elongation change by absorbing water or moisture, It will return to its original length when it is wetted. However, due to the small difference in hygroscopic elongation properties between the polyolefin component and the polyamide component, the dyeability and hygroscopic elongation properties of the fibers have certain deficiencies.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a composite fiber with good crimpability and self-expanding properties of moisture absorption and release.

The technical solution of the present invention is:

A composite fiber is formed by composite spinning of polymer A and polymer B, and the composite fiber contains 5-50wt% of polyether structural units; the composite fiber is treated in boiling water for 30 minutes, and the number of crimps after drying A is 10-30 pieces/2.5cm; the above-mentioned dried conjugate fibers are immersed in demineralized water at 20°C for 1 minute and then the surface moisture is wiped off, and the crimp number B is 0-50% of the crimp number A.

The polyether structural unit is preferably at least one of a polyethylene glycol structural unit, a polypropylene glycol structural unit, and a polybutylene glycol structural unit.

The polymer A and the polymer B are preferably polyester or polyamide, respectively.

The conjugate fiber is preferably a side-by-side type or an eccentric core-sheath type conjugate fiber.

The area ratio of the polymer A and the polymer B in the cross section of the composite fiber is preferably 20/80 to 80/20.

The present invention also discloses a method for preparing the composite fiber, which is formed by composite spinning of polymer A and polymer B, wherein the mass fraction of polyether structural units in polymer A is higher than the mass fraction of polyether structural units in polymer B The difference of the fractions is 10-60 wt %, preferably 30-50 wt %; the content of the polyether structural unit in the composite fiber is 5-50 wt %.

The mass fraction of the polyether structural unit in the polymer A is preferably 0-20 wt%; the mass fraction of the polyether structural unit in the polymer B is preferably 30-60 wt%.

In the present invention, two kinds of polymers with different polyether structural unit contents are made into composite fibers, so that the composite fibers have good crimping property and self-expanding properties of moisture absorption and desorption, and the fabric made from the fibers has good air permeability .

Detailed ways

The composite fiber of the present invention is formed by composite spinning of polymer A and polymer B. Due to the different contents of polyether structural units in polymer A and polymer B, their shrinkage and hygroscopic elongation are different, which in turn endows the composite fiber with good crimping and hygroscopic self-expansion properties.

The composite fibers of the present invention can be treated with boiling water for 30 minutes to obtain crimp characteristics, and the number of crimps A tested after drying is 10 to 30 pieces/2.5cm; the aforementioned dried composite fibers are immersed in demineralized water at 20°C for 1 minute. After wiping off the surface moisture, the curling number B was tested again, and the curling number B was 0-50% of the curling number A.

During the preparation of the fabric, the composite fibers are subjected to hot water treatment, so that the fibers in the obtained fabric have crimps. After the fabric absorbs water, the fibers in it will stretch spontaneously, the number of curls will decrease, the gap between the fibers in the fabric will become larger, and a convex part will be formed, which will give the fabric good air permeability; after drying, the curling of the fibers in the fabric increases, Return to the original level, so that the gaps between the fibers are restored to their original shape, and the bulge will be eliminated. Therefore, the fiber has good moisture absorption and quick-drying properties after being made into clothing, and has more advantages than traditional fibers in the field of sportswear.

The conjugated fiber of the present invention contains 5 to 50 wt % of polyether structural units. When the content of the polyether structural unit in the composite fiber is less than 5wt%, there are two cases, the first may be because the content of the polyether structural unit in the polymer A and the polymer B is small, that is, the polymer A and the polymer B have a small content of the polyether structural unit. The difference in the content of the polyether structural unit in the polymer B is small, and the difference in the hygroscopic elongation between the polymer A and the polymer B is small. At this time, it is difficult to make the composite fiber obtain good crimpability and moisture absorption and release. The second possibility is that the content of polyether structural units in polymer A (or polymer B) is high, but the composite ratio of polymer A (or polymer B) in the composite fiber is very small, even if polymer A The hygroscopic elongation differs greatly from that of polymer B, but because the composite ratio of polymer A (or polymer B) is very small, the composite fiber cannot obtain good crimping and moisture absorption and release self-stretching properties. When the content of the polyether structural unit in the composite fiber is more than 50 wt %, the spinnability of the fiber is poor.

The polyether structural units in the polymer A and the polymer B may be the same or different. The polyether structural unit is at least one of a polyethylene glycol structural unit, a polypropylene glycol structural unit, and a polybutylene glycol structural unit, wherein the crimpability and moisture absorption and release of the fiber to which the polyethylene glycol structural unit is added are spontaneous. The stretching properties are the most obvious and the price cost is relatively low, so polyethylene glycol structural units are preferred.

The polymer A and the polymer B can be various types of polymers known in the art, such as polyester, polyolefin, polyurethane, polycarbonate, polyolefin, polyamide, etc., which can be the same or different. However, considering the price cost and the scope of application of the product, polyester or polyamide is preferred.

The conjugated fibers of the present invention can be various types of conjugated fibers known in the art, such as concentric core-sheath type, side-by-side type, eccentric core-sheath type, etc., wherein the crimpability of the parallel-type conjugated fibers and the eccentric core-sheath type conjugated fibers The self-stretching properties of absorbing and releasing moisture are the most obvious, and the elasticity and drapability of the resulting fabric are also better, so the side-by-side composite fibers and the eccentric core-sheath composite fibers are preferred.

If the proportion of polymer A or polymer B in the composite fiber is too small, the curling property and the self-expansion property of moisture absorption and release of the composite fiber are not obvious, and the polymer is abnormally spit out during spinning, and the spinnability is poor. In the present invention, preferably, the area ratio of the polymer A and the polymer B on the cross section of the composite fiber is 20/80 to 80/20.

The invention also discloses a preparation method of the above-mentioned composite fiber, which is specifically:

Using side-by-side type, eccentric core-sheath type or other types of compound ports, the polymer A slices and the polymer B slices are fed into the A and B feed ports respectively, and after being melted by the melt spinning machine, they are compounded and spit out through the spinneret. silk. After cooling and oil feeding steps, the composite fiber is obtained by a spinning and drawing one-step coiling process. The difference between the mass fraction of the polyether structural unit in the polymer A and the mass fraction of the polyether structural unit in the polymer B is 10-60 wt%, and the content of the polyether structural unit in the composite fiber is 5-50 wt% .

The adopted one-step spinning and drawing process has a spinning speed of 1000-3000 m/min, preferably 1000-2000 m/min; an extension temperature of 20-90°C, preferably 20-50°C; and an extension ratio of 1.0-3.0 times.

In order to obtain good crimpability and moisture absorption and desorption self-stretching properties of the composite fiber, the difference between the content of the polyether structural unit in the polymer A and the polymer B is 10-60 wt%, when the difference between the two is less than At 10wt%, the difference between the hygroscopic elongation of polymer A and polymer B is small, and the composite fiber with good crimping and hygroscopic self-stretching properties cannot be obtained; when the difference between the two is greater than 60wt%, Poor spinnability may occur due to an excessively high content of polyether structural units in one of the polymers. The difference between the mass fraction of the polyether structural unit in the polymer A and the mass fraction of the polyether structural unit in the polymer B is preferably 30-50 wt%.

Under the condition that the above content difference is satisfied, the spinnability during production is also considered, and the hygroscopic elongation difference between the polymer A and the polymer B should be sufficient, the mass fraction of the polyether structural unit in the polymer A is preferably is 0-20 wt%, and the mass fraction of the polyether structural unit in the polymer B is 30-60 wt%.

In addition to the difference in the content of polyether structural units in polymer A and polymer B, it is also necessary to select an appropriate composite ratio of polymer A and polymer B, that is, it is preferable to select polymer A and polymer B on the cross section of the composite fiber. The area ratio of the polymer B is 20/80-80/20, so as to control the content of the polyether structural unit in the composite fiber in the range of 5-50 wt%.

Compared with the traditional polyester and polyamide fibers, the composite fiber prepared by the invention has good crimping property and self-expanding properties of moisture absorption and release. After the composite fiber is treated in boiling water for 30 minutes and dried, the number of crimps A measured is 10 to 30/2.5cm; the above-mentioned dried composite fiber is re-absorbed, and the number of crimps B measured is the number of crimps A. 0 to 50% of . The water absorption elongation of the fiber is 26-60%, and the elongation recovery rate is 85-100%. The fabric made from the fiber has good air permeability, so the fiber has good moisture absorption, quick-drying, elasticity and drapability after being made into clothing, which is more advantageous than traditional fibers in the field of sportswear.

Evaluation methods of physical properties and the like mentioned in the present invention are as follows.

1. Number of curls

Ten turns of yarn were wound at a tension of 0.1g/D with a yarn length measuring instrument, wrapped in a mesh bag of about 10cm×10cm, and then treated in boiling water for 30 minutes, air-dried at 20°C and 65%RH, and the humidity was adjusted. Dry heat treatment for 2 minutes in a relaxed state at 160°C in contact, cut a single yarn with a length of about 20cm from the treated silk under no tension and no tension, and hang it on the sample table. After applying pre-tension Wait for 30s, mark the two ends of the 5cm distance and remove the load, cut the yarn of the 5cm distance, measure the number under the microscope, and use the measured number of loops as the "crimp number in dry state".

In the same way, the yarn was wound ten times with a tension of 0.1g/D using a yarn length measuring instrument, wrapped in a mesh bag of about 10cm×10cm, and then treated in boiling water for 30 minutes, air-dried at 20°C and 65%RH, and adjusted the humidity, and then placed in a In a non-contact 160°C environment, dry heat treatment in a relaxed state for 2 minutes, then immerse the yarn in demineralized water adjusted to 20°C for 1 minute, then lift it from the water, and sandwich the remaining moisture on the fiber surface at 20°C 65°C. In the filter paper air-dried under %RH, place it on a water platform, place a load of 1.5g/cm ² for 2 seconds, wipe off the residual moisture on the fiber surface, and place the treated silk in a tension-free and unstretched state. Cut a single yarn with a length of about 20cm and hang it on the sample table, apply pre-tension and wait for 30s, mark both ends of the 5cm distance and remove the load, cut the yarn with a distance of 5cm, and put it under a microscope. The number of coils is measured, and the measured number of coils is regarded as the "wet state crimp number",

Pre-tensioning=0.18mN/tex×linear density.

2. Water absorption elongation:

The fiber was coiled, treated with boiling water for 30 minutes in a relaxed state, air-dried at 20°C 65% RH, adjusted for humidity, and then dry-heated for 2 minutes in a relaxed state in a non-contact 160°C environment. After standing at 20°C and 65% RH for 24 hours, a load of 0.88×10 ^-3 cN/dtex was applied to it, and the measured length of the wire was taken as the "wire length L ₁ at the time of drying"; After being immersed in demineralized water adjusted to 20°C for 1 minute, lifted from the water, the residual moisture on the fiber surface was sandwiched in filter paper air-dried at 20°C 65% RH, placed on a water platform, and loaded with 1.5g/cm ² of filter paper. The load was placed for 2 seconds, and the residual moisture on the fiber surface was wiped off. After 10 seconds, a load of 0.88× ₁₀ ^-3 cN/dtex was applied. The silk was air-dried at 20°C 65%RH and the humidity was adjusted, and then dry heat treatment was performed in a relaxed state at 160°C for 2 minutes in a non-contact environment, and the treated silk was left at 20°C 65%RH for 24 hours. , and a load of 0.88×10 ⁻³ cN/dtex was applied thereto, and the measured filament length was taken as the “filament length L ₃ at the time of re-drying”. The water absorption elongation and the elongation recovery were calculated by the following formulas. All measurements were performed in an environment of 20°C and 65% RH.

Water absorption elongation (%)=(L ₂ -L ₁ )/L ₁ ×100%,

Elongation recovery rate (%)=(L ₂ -L ₃ )/(L ₂ -L ₁ )×100%.

3. Content of polyether

Content of polyether: 1,1,3,3,3-hexafluoroisopropanol-D2 was added to the sample to make a solution for 1H-NMR test. The content of polyether was calculated from the area value of the peak.

4. The area ratio of polymer A and polymer B on the cross-section of the composite fiber

Fiber cross-section samples were prepared by paraffin-embedded sectioning, then photographed under an optical electron microscope and printed on paper. Further, cut the printed cross-section according to the polymer A part and the polymer B part, and weigh the weight of the polymer part A and the polymer part B respectively. Since the density and thickness of the paper are the same, they can be calculated from their weights. The weight ratio directly yields the area ratio of polymer A and polymer B across the fiber cross section.

The present invention will be described in detail below with reference to specific embodiments.

Example 1

Raw material: polymer A is a polyester without polyether structural unit, and polymer B is a polyester containing 40% wt polyether structural unit (polyethylene glycol structural unit).

The slices were dried to a moisture content of 400 ppm or less, put into a spinning silo, and spun with a side-by-side composite port. The spinning temperature was 290°C, the spinning speed was 1300 m/min, and the elongation ratio was 3.0 times. After spinning from the spinneret, it is cooled, and after oil is supplied, the composite fiber is obtained by one-step spinning. The area ratio of polymer A and polymer B on the cross section of the fiber is 50/50, the number of crimps after being treated in boiling water for 30 minutes and then dried is 16/2.5cm, and the dried composite fiber is re-absorbed water , the number of curls is reduced to 4/2.5cm. The water absorption elongation of the fibers was 30%, and the elongation recovery rate was 95%.

Example 2

Raw material: polymer A is a polyester without polyether structural unit, and polymer B is a polyamide containing 40% wt polyether structural unit (polyethylene glycol structural unit).

The slices were dried to a moisture content of 400 ppm or less, put into a spinning silo, and spun with a side-by-side composite port. The spinning temperature was 290°C, the spinning speed was 1300m/min, and the elongation ratio was 2.8 times. After spinning from the spinneret, it is cooled, and after oil is supplied, the composite fiber is obtained by one-step spinning. The area ratio of polymer A and polymer B on the cross section of the fiber is 50/50, the number of crimps after being treated in boiling water for 30 minutes and then dried is 18/2.5cm, and the dried composite fiber is re-absorbed water , the number of curls is reduced to 4/2.5cm. The water absorption elongation of the fibers was 35%, and the elongation recovery rate was 93%.

Example 3

Raw material: polymer A is a polyamide without polyether structural unit, and polymer B is a polyamide containing 40% wt polyether structural unit (polyethylene glycol structural unit).

The slices were dried to a moisture content of 400 ppm or less, put into a spinning silo, and spun with a side-by-side composite port. The spinning temperature was 260°C, the spinning speed was 1300m/min, and the elongation ratio was 2.6 times. After spinning from the spinneret, it is cooled, and after oil is supplied, the composite fiber is obtained by one-step spinning. The area ratio of polymer A and polymer B on the cross section of the fiber is 50/50, the number of crimps after being treated in boiling water for 30 minutes and then dried is 25/2.5cm, and the dried composite fiber is re-absorbed water , the number of curls is reduced to 6/2.5cm. The water-absorbing elongation of the fibers was 45%, and the elongation recovery was 90%.

Example 4

Raw materials: polymer A is a polyamide without polyether structural units, and polymer B is a polyamide containing 40% wt of polyether structural units (polypropylene glycol structural units).

The slices were dried to a moisture content of 400 ppm or less, put into a spinning silo, and spun with a side-by-side composite port. The spinning temperature was 260°C, the spinning speed was 1300m/min, and the elongation ratio was 2.6 times. After spinning from the spinneret, it is cooled, and after oil is supplied, the composite fiber is obtained by one-step spinning. The area ratio of polymer A and polymer B on the cross section of the fiber is 50/50, the number of crimps after being treated in boiling water for 30 minutes and then dried is 23/2.5cm, and the dried composite fiber is re-absorbed water , the number of curls is reduced to 11/2.5cm. The water absorption elongation of the fibers was 34%, and the elongation recovery rate was 93%.

Example 5

Raw material: polymer A is a polyamide without polyether structural unit, and polymer B is a polyamide containing 40% wt polyether structural unit (polybutylene glycol structural unit).

The slices were dried to a moisture content of 400 ppm or less, put into a spinning silo, and spun with a side-by-side composite port. The spinning temperature was 260°C, the spinning speed was 1300m/min, and the elongation ratio was 2.6 times. After spinning from the spinneret, it is cooled, and after oil is supplied, the composite fiber is obtained by one-step spinning. The area ratio of polymer A and polymer B on the cross section of the fiber is 50/50, the number of crimps after being treated in boiling water for 30 minutes and then dried is 23/2.5cm, and the dried composite fiber is re-absorbed water , the number of curls is reduced to 9/2.5cm. The water absorption elongation of the fibers was 38%, and the elongation recovery rate was 94%.

Example 6

Raw material: polymer A is a polyamide without polyether structural unit, and polymer B is a polyamide containing 20% wt polyether structural unit (polyethylene glycol structural unit).

The slices were dried to a moisture content of 400 ppm or less, put into a spinning silo, and spun with a side-by-side composite port. The spinning temperature was 260°C, the spinning speed was 1300m/min, and the elongation ratio was 2.6 times. After spinning from the spinneret, it is cooled, and after oil is supplied, the composite fiber is obtained by one-step spinning. The area ratio of polymer A and polymer B on the cross section of the fiber is 50/50, the number of crimps after being treated in boiling water for 30 minutes and then dried is 20/2.5cm, and the dried composite fiber is re-absorbed water , the number of curls is reduced to 7/2.5cm. The water absorption elongation of the fibers was 37%, and the elongation recovery rate was 95%.

Example 7

Raw material: polymer A is a polyamide without polyether structural unit, and polymer B is a polyamide containing 60% wt polyether structural unit (polyethylene glycol structural unit).

The slices were dried to a moisture content of 400 ppm or less, put into a spinning silo, and spun with a side-by-side composite port. The spinning temperature was 260°C, the spinning speed was 1300m/min, and the elongation ratio was 2.6 times. After spinning from the spinneret, it is cooled, and after oil is supplied, the composite fiber is obtained by one-step spinning. The area ratio of polymer A and polymer B on the cross section of the fiber is 50/50, the number of crimps after being treated in boiling water for 30 minutes and then dried is 30/2.5cm, and the dried composite fiber is re-absorbed water , the number of curls is reduced to 7/2.5cm. The water absorption elongation of the fibers was 55%, and the elongation recovery rate was 90%.

Example 8

Raw material: polymer A is a polyamide containing 20%wt of polyether structural units (polyethylene glycol structural units), and polymer B is a polyamide containing 60%wt of polyether structural units (polyethylene glycol structural units).

The slices were dried to a moisture content of 400 ppm or less, put into a spinning silo, and spun with a side-by-side composite port. The spinning temperature was 260°C, the spinning speed was 1300m/min, and the elongation ratio was 2.6 times. After spinning from the spinneret, it is cooled, and after oil is supplied, the composite fiber is obtained by one-step spinning. The area ratio of polymer A and polymer B on the cross section of the fiber is 50/50, the number of crimps after being treated in boiling water for 30 minutes and then dried is 22/2.5cm, and the dried composite fiber is re-absorbed water , the number of curls is reduced to 5/2.5cm. The water absorption elongation of the fiber was 60%, and the elongation recovery rate was 88%.

Example 9

The slices were dried to a moisture content of 400 ppm or less, put into a spinning silo, and spun with a side-by-side composite port. The spinning temperature was 260°C, the spinning speed was 1300m/min, and the elongation ratio was 2.6 times. After spinning from the spinneret, it is cooled, and after oil is supplied, the composite fiber is obtained by one-step spinning. The area ratio of polymer A and polymer B on the cross section of the fiber is 80/20, the number of crimps after being treated in boiling water for 30 minutes and then dried is 10/2.5cm, and the dried composite fiber is re-absorbed water , the number of curls is reduced to 0/2.5cm. The water absorption elongation of the fiber was 30%, and the elongation recovery rate was 96%.

Example 10

The slices were dried to a moisture content of 400 ppm or less, put into a spinning silo, and spun with a side-by-side composite port. The spinning temperature was 260°C, the spinning speed was 1300m/min, and the elongation ratio was 2.6 times. After spinning from the spinneret, it is cooled, and after oil is supplied, the composite fiber is obtained by one-step spinning. The area ratio of polymer A and polymer B on the cross section of the fiber is 20/80, the number of crimps after being treated in boiling water for 30 minutes and then dried is 12/2.5cm, and the dried composite fiber is re-absorbed water , the number of curls is reduced to 2/2.5cm. The water absorption elongation of the fibers was 52%, and the elongation recovery was 90%.

Example 11

The slices were dried to a moisture content of less than 400 ppm, put into a spinning silo, and spun with an eccentric core-sheath type composite gold. The spinning temperature was 260°C, the spinning speed was 1300m/min, and the elongation ratio was 2.6 times. After spinning from the spinneret, it is cooled, and after oil is supplied, the composite fiber is obtained by one-step spinning. The area ratio of polymer A and polymer B on the cross section of the fiber is 50/50, the number of crimps after being treated in boiling water for 30 minutes and then dried is 24/2.5cm, and the dried composite fiber is re-absorbed water , the number of curls is reduced to 6/2.5cm. The water absorption elongation of the fibers was 46%, and the elongation recovery was 91%.

Example 12

Raw material: polymer A is a polyamide without polyether structural unit, and polymer B is a polyamide containing 10% wt polyether structural unit (polyethylene glycol structural unit).

The slices were dried to a moisture content of 400 ppm or less, put into a spinning silo, and spun with a side-by-side composite port. The spinning temperature was 260°C, the spinning speed was 1300m/min, and the elongation ratio was 2.6 times. After spinning from the spinneret, it is cooled, and after oil is supplied, the composite fiber is obtained by one-step spinning. The area ratio of polymer A and polymer B on the cross section of the fiber is 50/50, the number of crimps after being treated in boiling water for 30 minutes and then dried is 20/2.5cm, and the dried composite fiber is re-absorbed water , the number of curls is reduced to 10/2.5cm. The water absorption elongation of the fibers was 26%, and the elongation recovery rate was 98%.

Comparative Example 1

Raw material: polymer A is a polyamide without polyether structural unit, and polymer B is a polyamide containing 80% wt polyether structural unit (polyethylene glycol structural unit).

Dry the chips to a moisture content of less than 400 ppm, put them into a spinning silo, spin them with a side-by-side composite fiber, and adjust the feed ratio of polymer A and polymer B, so that the target composite fiber is cross-sectioned with polymer A and polymer B. The area ratio is 50/50. The spinning temperature was 260°C, the spinning speed was 1300m/min, and the elongation ratio was 2.6 times. After spinning from the spinneret, it is cooled, and after oil is supplied, it is spun by one-step method. Because the polyethylene glycol content in polymer B is too high, it is easy to break the yarn and the spinning is impossible.

Comparative Example 2

Raw material: polymer A is a polyamide containing 50%wt of polyether structural units (polyethylene glycol structural units), and polymer B is a polyamide containing 70%wt of polyether structural units (polyethylene glycol structural units).

Dry the chips to a moisture content of less than 400 ppm, put them into a spinning silo, spin them with a side-by-side composite fiber, and adjust the feed ratio of polymer A and polymer B, so that the target composite fiber is cross-sectioned with polymer A and polymer B. The area ratio is 50/50. The spinning temperature was 260°C, the spinning speed was 1300m/min, and the elongation ratio was 2.6 times. After spinning from the spinneret, it is cooled, and after oil is supplied, it is spun in one step. Because the polyethylene glycol content in the polymer as a whole is too high, it is easy to break the yarn and the spinning is impossible.

Comparative Example 3

Raw material: polymer A is a polyamide without polyether structural unit, and polymer B is a polyamide containing 2% wt polyether structural unit (polyethylene glycol structural unit).

The slices were dried to a moisture content of 400 ppm or less, put into a spinning silo, and spun with a core-sheath type composite mouth gold. The spinning temperature was 260°C, the spinning speed was 1300m/min, and the elongation ratio was 2.6 times. After spinning from the spinneret, it is cooled, and after oil is supplied, the composite fiber is obtained by one-step spinning. The area ratio of polymer A and polymer B on the cross section of the fiber is 50/50, the number of crimps after being treated in boiling water for 30 minutes and then dried is 10/2.5cm, and the dried composite fiber is re-absorbed water , the number of curls is reduced to 8/2.5cm. The water absorption elongation of the fibers was 5%, and the elongation recovery rate was 100%. Due to the low polyether content, good water-absorbing elongation properties cannot be produced.

Comparative Example 4

Raw material: polyamide containing 40% wt of polyether structural units (polyethylene glycol structural units).

The slices were dried to a moisture content of less than 400 ppm, put into a spinning silo for spinning, and spun with a circular die. The spinning temperature was 260 °C, the spinning speed was 1300 m/min, and the elongation ratio was 2.6 times. After spinning out of the spinneret, it is cooled, and after oil is supplied, single-component circular fibers are obtained by one-step spinning. The fiber was treated in boiling water for 30 minutes and then dried, and the number of crimps was 0/2.5cm, and the dried composite fiber was re-absorbed, and the number of crimps was reduced to 0/2.5cm. The water absorption elongation of the fibers was 10%, and the elongation recovery rate was 100%. The single-component cross-sectional structure cannot produce water-absorbing elongation characteristics.

The specific parameters of Examples and Comparative Examples are shown in Table 1 and Table 2.

Claims

The composite fiber is formed by composite spinning of polymer A and polymer B, and is characterized in that: the composite fiber contains 5-50 wt% of polyether structural units; the composite fiber is treated in boiling water for 30 minutes, and then dried. The number of crimps A is 10 to 30 pieces/2.5cm; the dried conjugate fibers are immersed in demineralized water at 20°C for 1 minute, and then the surface moisture is wiped off, and the number of crimps B is 0 to 50% of the number of crimps A.
The composite fiber according to claim 1, wherein the polyether structural unit is at least one of a polyethylene glycol structural unit, a polypropylene glycol structural unit, and a polybutylene glycol structural unit.
The composite fiber according to claim 1 or 2, wherein the polymer A and the polymer B are polyester or polyamide, respectively.
The composite fiber according to claim 1 or 2, wherein the composite fiber is a side-by-side or eccentric core-sheath composite fiber.
The composite fiber according to claim 1 or 2, wherein the area ratio of the polymer A and the polymer B on the cross-section of the composite fiber is 20/80 to 80/20.
The preparation method of the composite fiber according to claim 1 is formed by composite spinning of polymer A and polymer B, wherein the mass fraction of the polyether structural unit in the polymer A is higher than that of the polyether structure in the polymer B. The difference in mass fraction of units is 10-60 wt %, and the content of the polyether structural unit in the composite fiber is 5-50 wt %.
The preparation method of the composite fiber according to claim 6, wherein the mass fraction of the polyether structural unit in the polymer A is 0-20 wt%; the mass fraction of the polyether structural unit in the polymer B is 30 wt% ~60 wt%.
The method for preparing a composite fiber according to claim 6 or 7, wherein the difference in mass fraction of the polyether structural units in the polymer A and the polymer B is 30-50 wt%.