Eccentric core sheath composite fiber

Abstract

The invention discloses an eccentric core-sheath composite fiber which mainly comprises a core component and a sheath component with different intrinsic viscosities, and the ratio of the distance between the center of gravity of the core component and the center of gravity of the sheath component to the diameter of the cross section of the composite fiber is 0.2-0.8; the contact surface of the core component and the sheath component on the cross section of the composite fiber is wave-shaped. According to the composite fiber, the contact area of the core component and the sheath component is large, stripping of the core component and the sheath component can be effectively restrained, the bending phenomenon at an outlet of a spinneret plate is improved, the spinning performance is better, and the strength and elongation are high.

Description

Technical Field

[0001] The present invention relates to an eccentric core-sheath composite fiber, and specifically, to a core-sheath composite fiber with a wavy contact surface between the core component and the sheath component, good strength and elongation, and excellent spinnability. Background Art

[0002] With the continuous pursuit of clothing performance and styles by people, the differentiation and high-endization of synthetic fibers are an inevitable choice in the market. Elastic fibers have always been a popular field. In particular, bicomponent side-by-side composite fibers made by imitating wool have excellent properties such as fluffiness and elasticity due to the different thermal expansion and contraction properties and wet expansion and contraction properties of the two polymers, which will form a three-dimensional spiral structure after heating.

[0003] Chinese Patent CN101851812A and Chinese Patent CN108138379A disclose elastic side-by-side composite yarns made of polybutylene terephthalate and polyester with different viscosities. However, due to the short contact surface of the two components, component peeling is likely to occur during processing, resulting in fuzz, which affects the quality of the fiber. At the same time, when spinning and cooling, the low-viscosity polyester will inhibit the orientation crystallization of the high-viscosity polybutylene terephthalate, resulting in low strength and elongation of the yarn. In addition, when the viscosity difference between the two polymers on both sides is too large, the yarn is prone to bend when ejected from the spinneret during the melt spinning process, that is, the high-viscosity side of the fiber at the discharge hole bends towards the spinneret direction, resulting in broken filaments and floating filaments, affecting production efficiency and increasing manufacturing costs. Summary of the Invention

[0004] The purpose of the present invention is to provide a core-sheath composite fiber with excellent strength and elongation, which has excellent spinnability and high production efficiency.

[0005] The technical solution of the present invention is as follows:

[0006] An eccentric core-sheath composite fiber mainly contains a core component and a sheath component with different intrinsic viscosities. The ratio of the distance between the centroid of the core component and the centroid of the sheath component to the diameter of the cross-section of the composite fiber is 0.2 - 0.8; the contact surface between the core component and the sheath component on the cross-section of the composite fiber is wavy.

[0007] The number of the wavy shapes is preferably more than 8.

[0008] The ratio of the diameter of the minimum circumscribed circle of the wavy shape to the diameter of the cross-section of the fiber is preferably 0.01 - 0.20.

[0009] The difference in intrinsic viscosity between the core component and the sheath component is preferably 0.50 - 0.80 dl / g.

[0010] The core component and the sheath component are respectively selected from polyester, cation-modified polyester, polyolefin or polyamide.

[0011] By setting the contact surface between the core component and the sheath component on the cross-section of the composite fiber to be wavy, the contact area between the core component and the sheath component is increased, the peeling of the core and sheath components is inhibited, and the spinnability and strength and elongation of the composite fiber are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic cross-sectional view of the composite fiber described in the present invention.

[0013] Figure 2 It is a paraffin-embedded photograph of the cross-section of the composite fiber described in the present invention.

[0014] Figure 3 It is a schematic view of the minimum circumscribed circle passing through the wave crest and the two side wave troughs of the present invention.

[0015] Figure 4 It is a schematic view when the core component of the present invention is of a special shape.

[0016] Figure 5 It is a schematic view of the cross-section of the composite fiber of the present invention being of a special shape. DETAILED DESCRIPTION OF THE INVENTION

[0017] In the side-by-side elastic composite fiber or eccentric core-sheath elastic composite fiber prepared by an ordinary method, the contact surface between the two components is a straight line or a single arc, and the overall contact surface is small, and it is easy to peel off during the processing, resulting in problems such as hairiness of the fiber. And due to the viscosity difference between the two components of the elastic fiber, there is a shrinkage difference between the two components at the orifice, resulting in bending of the fiber and filament breakage, reducing the spinnability of the fiber.

[0018] By defining that the contact surface between the core component and the sheath component on the cross-section of the composite fiber is wavy, the contact surface between the core component and the sheath component is increased, and the peeling of the core component and the sheath component can be better inhibited. At the same time, the wavy contact surface can relieve the bending caused by the viscosity difference between the core-sheath components and reduce the occurrence of filament breakage.

[0019] The cross-section of the composite fiber can be circular, or can be of a special shape such as flat, dumbbell-shaped, cross-shaped, etc. For the diameter of the special shape, it is the average value of the longest length and the shortest length that can be measured within the cross-section of the fiber.

[0020] The wavy shape refers to a shape having wave crests and wave troughs and the wave crests and wave troughs being directly connected (similar to the shape of "~"). For the purpose of greatly increasing the contact surface between the core component and the sheath component, the number of wavy shapes on the cross-section of a single fiber of the composite fiber described in the present invention is preferably more than 8, so that the effect of inhibiting peeling can be more easily exerted.

[0021] In addition to the number and distribution of the waveforms, the size of the waveforms also affects the size of the contact surface between the core component and the sheath component. In the present invention, the amplitude of the waveform is characterized by the ratio of the diameter of the minimum circumscribed circle of the waveform to the diameter of the fiber cross-section. Within a certain range, the amplitude of the waveform can increase the contact surface between the core component and the sheath component. If the diameter of the minimum circumscribed circle of the waveform is very small and it is difficult to observe a shape similar to "~" even under a high-power microscope, then its effect of increasing the contact surface between the core component and the sheath component is very limited, and it cannot effectively reduce the occurrence of broken filaments. Eventually, the strength and elongation of the composite fiber are similar to those of ordinary eccentric core-sheath composite fibers. If the diameter of the minimum circumscribed circle of the waveform is very large, especially when it is close to the diameter of the arc of the core component, its effect of increasing the contact surface between the core component and the sheath component is also very limited, and it cannot effectively reduce the occurrence of broken filaments. Eventually, the strength and elongation of the composite fiber are similar to those of ordinary eccentric core-sheath composite fibers. In the present invention, it is preferred that the ratio of the diameter of the minimum circumscribed circle of the waveform to the diameter of the fiber cross-section is 0.01 to 0.20. Within this range, the contact surface between the core component and the sheath component is relatively large, there are fewer or no broken filaments during spinning, and the strength and elongation of the final composite fiber are good.

[0022] In addition, in the present invention, by defining the ratio of the distance between the centroid of the core component and the centroid of the sheath component to the diameter of the composite fiber cross-section to be 0.2 to 0.8, the composite fiber has good elasticity and crimp. If the ratio is less than 0.2, the centroid distance between the core component and the sheath component is too small, which will inhibit the orientation of the high-viscosity component and result in poor elasticity of the yarn. If the ratio is greater than 0.8, the composite fiber cannot form a regular and dense coiling, and the hand feeling deteriorates.

[0023] In order to obtain an elastic composite fiber and at the same time reduce or prevent the yarn from bending at the spinneret exit during melt spinning, thereby reducing the occurrence of broken filaments and floating filaments and lowering the production cost, in the present invention, it is preferred that the difference in intrinsic viscosity between the core component and the sheath component is 0.30 to 0.80 dl / g. As the viscosity difference decreases, the elasticity of the composite fiber also decreases; as the viscosity difference increases, the elasticity of the composite fiber also increases to some extent, but the bending of the yarn at the spinneret exit during spinning will gradually become serious, eventually resulting in frequent occurrence of broken filaments and floating filaments.

[0024] The present invention does not particularly limit the ratio of the core component to the sheath component, and the general ranges in the prior art can be used. In order to obtain a composite fiber with better elasticity and hand feeling, it is preferred that the area ratio of the core component to the sheath component on the fiber cross-section is 30 / 70 to 70 / 30.

[0025] The polymers forming the core component and the sheath component can be the same or different, and the category of the polymer is not particularly limited either. It can be various polymers that can be melt-spun in the prior art, such as polyester, polyolefin, polyamide, polylactic acid, polyurethane, polyphenylene sulfide, etc. Each polymer as cited above includes ordinary polymers and also includes modified polymers. The modified polymer can be a cationic modified polymer of a copolymerizable dyeable group, a matt modified polymer with matt particles added, a modified polymer with other functional particles added, etc. Considering comprehensively aspects such as spinnability and the composite characteristics of various polymers, the preferred core component and the sheath component of the present invention are polyester, polyolefin or polyamide, respectively.

[0026] The present invention does not specifically limit the preparation method of the eccentric core-sheath composite fiber, and the general method of composite spinning in the prior art can be used. For example, the core component polymer slices and the sheath component polymer slices are dried separately to reduce their moisture to less than 100ppm, and then respectively put into the composite spinning machine, and the spinning temperature is generally 260-310°C. The core component polymer and the sheath component polymer are respectively flowed into the spinneret through the spinning assembly and spun out, and after being cooled by side blowing and oiled by the oil nozzle, they are wound by rollers and winders, and the winding speed is generally 1000-3000m / min to obtain pre-oriented yarns. Finally, after false twisting, the eccentric core-sheath composite fiber with excellent elasticity mentioned in this patent is obtained.

[0027] The wavy contact surface between the core component and the sheath component can be formed by known methods, such as using a composite spinneret having wavy intersection holes at the junction of the core component and the sheath component outlet on an eccentric core-sheath type spinneret.

[0028] The present invention makes the contact surface of the core component and the sheath component wavy, so that the contact area of the core component and the sheath component in the composite fiber is larger, which can effectively inhibit the peeling of the core sheath component and improve the elbow phenomenon at the outlet of the spinneret, and has good spinnability and high strength and elongation.

[0029] The test methods of various parameters involved in the present invention are as follows:

[0030] (1) Composite fiber cross-sectional diameter

[0031] The cross section of the composite fiber was cut by the copper plate method or paraffin embedding method, and the diameter of the cross section of a single fiber was measured under a microscope. The final result was the average value of 5 tests.

[0032] (2) The distance between the center of gravity of the core component and the sheath component on the cross section of the composite fiber

[0033] After printing the yarn cross section, cut the polymers along the boundary of the two polymer components, use the hanging method to determine the position of the center of gravity of each polymer, and then piece the polymers together to measure the distance between the center of gravity of the two polymers. The test results are taken as the average of 3 times.

[0034] (3) Diameter of the wavy minimum circumscribed circle

[0035] Select the highest peak point of the wavy shape and the two lowest points of the left and right wave troughs to form a circle, and the diameter of the circumscribed circle can be measured. The test results are the average of 3 measurements.

[0036] (4) Intrinsic viscosity of the core component and the sheath component

[0037] Dissolve 0.8 g of the polymer in 10 ml of the corresponding dissolution solution, and use an Ubbelohde viscometer to measure its intrinsic viscosity under the condition that the water bath temperature is 25 ± 0.2 °C.

[0038] (5) Strength-elongation product of the composite fiber

[0039] Test the strength and elongation of the composite fiber according to the standard GB / T14344-2008, and calculate the strength-elongation product of the fiber using the following formula:

[0040] Strength-elongation product = Strength × (Elongation) 1 / 2 。

[0041] The final result is the average of 3 measurements.

[0042] (6) Spinnability

[0043] Count the number of occurrences of floating filaments and broken filaments during the spinning process. When the number of floating filaments and broken filaments is less than 1 time / t, the spinnability is judged as 〇; when the number of floating filaments and broken filaments is 2 - 3 times / t, the spinnability is judged as Δ; when the number of floating filaments and broken filaments is more than 4 times / t, the spinnability is judged as ×.

[0044] (7) Elasticity of the composite fiber

[0045] Measure according to the standard JID L1090-1992. When the measured elastic elongation rate is less than 30%, the elasticity is judged as ×; when the elastic elongation rate is 30 - 50%, the elasticity is judged as Δ; when the elastic elongation rate is greater than 50%, the elasticity is judged as 〇.

[0046] The present invention will be described in detail below with reference to the embodiments.

[0047] Example 1

[0048] Polybutylene terephthalate with an intrinsic viscosity of 1.20 dl / g (core component) and polyethylene terephthalate with an intrinsic viscosity of 0.65 dl / g (sheath component) were selected for composite spinning. They were dried separately to make the moisture less than 100 ppm, then put into the spinning machine. The composite ratio was 50 / 50. An eccentric core-sheath type composite spinneret was used for spinning. The raw silk variety was controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers was 18, the minimum circumscribed circle diameter of the wave shape was 1.50 microns, and the distance between the center of gravity points of the core component and the sheath component was 7.2 microns.

[0049] The wound pre-oriented yarn was subjected to false twisting processing with a hot needle false twisting disc. The hot needle temperature was 90 °C, the hot box temperature was 180 °C, and the stretching speed was 500 m / min. The final DTY variety was 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn were measured. The specific values are shown in Table 1.

[0050] Example 2

[0051] Polybutylene terephthalate with an intrinsic viscosity of 1.20 dl / g (core component) and polyethylene terephthalate with an intrinsic viscosity of 0.65 dl / g (sheath component) were selected for composite spinning. They were dried separately to make the moisture less than 100 ppm, then put into the spinning machine. The composite ratio was 50 / 50. An eccentric core-sheath type composite spinneret was used for spinning. The raw silk variety was controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers was 18, the minimum circumscribed circle diameter of the wave shape was 1.50 microns, and the distance between the center of gravity points of the core component and the sheath component was 3.6 microns.

[0052] The wound pre-oriented yarn was subjected to false twisting processing with a hot needle false twisting disc. The hot needle temperature was 90 °C, the hot box temperature was 180 °C, and the stretching speed was 500 m / min. The final DTY variety was 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn were measured. The specific values are shown in Table 1.

[0053] Example 3

[0054] Polybutylene terephthalate with an intrinsic viscosity of 1.20 dl / g (core component) and polyethylene terephthalate with an intrinsic viscosity of 0.65 dl / g (sheath component) were selected for composite spinning. They were dried separately to make the moisture less than 100 ppm, then put into the spinning machine. The composite ratio was 50 / 50. An eccentric core-sheath type composite spinneret was used for spinning. The raw silk variety was controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers was 18, the minimum circumscribed circle diameter of the wave shape was 1.50 microns, and the distance between the center of gravity points of the core component and the sheath component was 14.4 microns.

[0055] The wound pre-oriented yarn is subjected to false twisting with a hot needle false twisting disc. The hot needle temperature is 90 °C, the hot box temperature is 180 °C, and the stretching speed is 500 m / min. The final DTY variety is 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn are measured. The specific values are shown in Table 1.

[0056] Example 4

[0057] Polybutylene terephthalate with an intrinsic viscosity of 1.20 dl / g (core component) and polyethylene terephthalate with an intrinsic viscosity of 0.65 dl / g (sheath component) are selected for composite spinning. They are dried separately to make the moisture less than 100 ppm, and then put into the spinning machine. The composite ratio is 50 / 50. An eccentric core-sheath type composite spinneret is used for spinning. The raw yarn variety is controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers is 8, the minimum circumscribed circle diameter of the wave shape is 1.50 microns, and the distance between the centroid points of the core component and the sheath component is 7.2 microns.

[0058] The wound pre-oriented yarn is subjected to false twisting with a hot needle false twisting disc. The hot needle temperature is 90 °C, the hot box temperature is 180 °C, and the stretching speed is 500 m / min. The final DTY variety is 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn are measured. The specific values are shown in Table 1.

[0059] Example 5

[0060] Polybutylene terephthalate with an intrinsic viscosity of 1.20 dl / g (core component) and polyethylene terephthalate with an intrinsic viscosity of 0.65 dl / g (sheath component) are selected for composite spinning. They are dried separately to make the moisture less than 100 ppm, and then put into the spinning machine. The composite ratio is 50 / 50. An eccentric core-sheath type composite spinneret is used for spinning. The raw yarn variety is controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers is 18, the minimum circumscribed circle diameter of the wave shape is 0.18 microns, and the distance between the centroid points of the core component and the sheath component is 7.2 microns.

[0061] The wound pre-oriented yarn is subjected to false twisting with a hot needle false twisting disc. The hot needle temperature is 90 °C, the hot box temperature is 180 °C, and the stretching speed is 500 m / min. The final DTY variety is 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn are measured. The specific values are shown in Table 1.

[0062] Example 6

[0063] Polybutylene terephthalate with an intrinsic viscosity of 1.20 dl / g (core component) and polyethylene terephthalate with an intrinsic viscosity of 0.65 dl / g (sheath component) were selected for composite spinning. They were dried separately to make the moisture less than 100 ppm, then put into the spinning machine. The composite ratio was 50 / 50, and an eccentric core-sheath type composite spinneret was used for spinning. The raw silk variety was controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers was 18, the minimum circumscribed circle diameter of the wave shape was 3.60 microns, and the distance between the center of gravity points of the core component and the sheath component was 7.2 microns.

[0064] The wound pre-oriented yarn was subjected to false twist processing with a hot needle false twist disc. The hot needle temperature was 90 °C, the hot box temperature was 180 °C, and the draw speed was 500 m / min. The final DTY variety was 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the DTY yarn after false twisting were measured. The specific values are shown in Table 1.

[0065] Example 7

[0066] Polybutylene terephthalate with an intrinsic viscosity of 1.20 dl / g (core component) and cationic polyethylene terephthalate with an intrinsic viscosity of 0.50 dl / g (sheath component) were selected for composite spinning. They were dried separately to make the moisture less than 100 ppm, then put into the spinning machine. The composite ratio was 50 / 50, and an eccentric core-sheath type composite spinneret was used for spinning. The raw silk variety was controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers was 18, the minimum circumscribed circle diameter of the wave shape was 1.50 microns, and the distance between the center of gravity points of the core component and the sheath component was 7.2 microns.

[0067] The wound pre-oriented yarn was subjected to false twist processing with a hot needle false twist disc. The hot needle temperature was 90 °C, the hot box temperature was 180 °C, and the draw speed was 500 m / min. The final DTY variety was 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the DTY yarn after false twisting were measured. The specific values are shown in Table 1.

[0068] Example 8

[0069] Polybutylene terephthalate with an intrinsic viscosity of 1.45 dl / g (core component) and polyethylene terephthalate with an intrinsic viscosity of 0.65 dl / g (sheath component) were selected for composite spinning. They were dried separately to make the moisture less than 100 ppm, then put into the spinning machine. The composite ratio was 50 / 50, and an eccentric core-sheath type composite spinneret was used for spinning. The raw silk variety was controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers was 18, the minimum circumscribed circle diameter of the wave shape was 1.50 microns, and the distance between the center of gravity points of the core component and the sheath component was 7.2 microns.

[0070] The wound pre-oriented yarn is subjected to false twist processing with a hot needle false twist disc. The hot needle temperature is 90 °C, the hot box temperature is 180 °C, and the stretching speed is 500 m / min. The final DTY variety is 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn are measured. The specific values are shown in Table 1.

[0071] Example 9

[0072] Polybutylene terephthalate with an intrinsic viscosity of 1.20 dl / g (core component) and cationic polyethylene terephthalate with an intrinsic viscosity of 0.50 dl / g (sheath component) are selected for composite spinning. They are dried separately to make the moisture less than 100 ppm, then put into the spinning machine. The composite ratio is 50 / 50. An eccentric core-sheath type composite spinneret is used for spinning. The raw yarn variety is controlled to be 150 dtex / 36F. The number of waves at the junction of the two polymers is 14, the minimum circumscribed circle diameter of the wave shape is 2.00 microns, and the distance between the centroid points of the core component and the sheath component is 7.2 microns.

[0073] The wound pre-oriented yarn is subjected to false twist processing with a hot needle false twist disc. The hot needle temperature is 90 °C, the hot box temperature is 180 °C, and the stretching speed is 500 m / min. The final DTY variety is 84 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn are measured. The specific values are shown in Table 1.

[0074] Example 10

[0075] Polyamide with an intrinsic viscosity of 2.40 dl / g (core component) and polyamide with an intrinsic viscosity of 1.80 dl / g (sheath component) are selected for composite spinning. They are dried separately to make the moisture less than 100 ppm, then put into the spinning machine. The composite ratio is 50 / 50. An eccentric core-sheath type composite spinneret is used for spinning. The raw yarn variety is controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers is 18, the minimum circumscribed circle diameter of the wave shape is 1.50 microns, and the distance between the centroid points of the core component and the sheath component is 7.2 microns.

[0076] The wound pre-oriented yarn is subjected to false twist processing with a hot needle false twist disc. The hot needle temperature is 90 °C, the hot box temperature is 180 °C, and the stretching speed is 500 m / min. The final DTY variety is 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn are measured. The specific values are shown in Table 1.

[0077] Example 11

[0078] Polypropylene with an intrinsic viscosity of 1.20 dl / g (core component) and polypropylene with an intrinsic viscosity of 0.60 dl / g (sheath component) were selected for composite spinning. They were dried separately to make the moisture content less than 100 ppm, then put into the spinning machine. The composite ratio was 50 / 50, and an eccentric core-sheath type composite spinneret was used for spinning. The raw silk variety was controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers was 18, the minimum circumscribed circle diameter of the wave shape was 1.50 microns, and the distance between the center of gravity points of the core component and the sheath component was 7.2 microns.

[0079] The wound pre-oriented yarn was subjected to false twist processing with a hot needle false twist disc. The hot needle temperature was 90 °C, the hot box temperature was 180 °C, and the stretching speed was 500 m / min. The final DTY variety was 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn were measured. The specific values are shown in Table 1.

[0080] Example 12

[0081] Polybutylene terephthalate with an intrinsic viscosity of 1.20 dl / g (core component) and cationic polyethylene terephthalate with an intrinsic viscosity of 0.50 dl / g (sheath component) were selected for composite spinning. They were dried separately to make the moisture content less than 100 ppm, then put into the spinning machine. The composite ratio was 30 / 70, and an eccentric core-sheath type composite spinneret was used for spinning. The raw silk variety was controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers was 18, the minimum circumscribed circle diameter of the wave shape was 1.50 microns, and the distance between the center of gravity points of the core component and the sheath component was 7.2 microns.

[0082] The wound pre-oriented yarn was subjected to false twist processing with a hot needle false twist disc. The hot needle temperature was 90 °C, the hot box temperature was 180 °C, and the stretching speed was 500 m / min. The final DTY variety was 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn were measured. The specific values are shown in Table 1.

[0083] Example 13

[0084] Polybutylene terephthalate with an intrinsic viscosity of 1.20 dl / g (core component) and cationic polyethylene terephthalate with an intrinsic viscosity of 0.50 dl / g (sheath component) were selected for composite spinning. They were dried separately to make the moisture content less than 100 ppm, then put into the spinning machine. The composite ratio was 70 / 30, and an eccentric core-sheath type composite spinneret was used for spinning. The raw silk variety was controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers was 18, the minimum circumscribed circle diameter of the wave shape was 1.50 microns, and the distance between the center of gravity points of the core component and the sheath component was 7.2 microns.

[0085] The wound pre-oriented yarn is subjected to false twist processing using a hot needle false twist disc. The hot needle temperature is 90 °C, the hot box temperature is 180 °C, and the stretching speed is 500 m / min. The final DTY variety is 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn are measured. The specific values are shown in Table 1.

[0086] Example 14

[0087] Polybutylene terephthalate with an intrinsic viscosity of 1.20 dl / g (core component) and polyethylene terephthalate with an intrinsic viscosity of 0.65 dl / g (sheath component) are selected for composite spinning. They are dried separately to make the moisture less than 100 ppm, and then put into the spinning machine. The composite ratio is 50 / 50. An eccentric core-sheath type composite spinneret is used for spinning. The raw yarn variety is controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers is 4, the minimum circumscribed circle diameter of the wave shape is 1.50 microns, and the distance between the centroid points of the core component and the sheath component is 7.2 microns.

[0088] The wound pre-oriented yarn is subjected to false twist processing using a hot needle false twist disc. The hot needle temperature is 90 °C, the hot box temperature is 180 °C, and the stretching speed is 500 m / min. The final DTY variety is 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn are measured. The specific values are shown in Table 1.

[0089] Example 15

[0090] Polybutylene terephthalate with an intrinsic viscosity of 1.20 dl / g (core component) and polyethylene terephthalate with an intrinsic viscosity of 0.65 dl / g (sheath component) are selected for composite spinning. They are dried separately to make the moisture less than 100 ppm, and then put into the spinning machine. The composite ratio is 50 / 50. An eccentric core-sheath type composite spinneret is used for spinning. The raw yarn variety is controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers is 18, the minimum circumscribed circle diameter of the wave shape is 0.09 microns, and the distance between the centroid points of the core component and the sheath component is 7.2 microns.

[0091] The wound pre-oriented yarn is subjected to false twist processing using a hot needle false twist disc. The hot needle temperature is 90 °C, the hot box temperature is 180 °C, and the stretching speed is 500 m / min. The final DTY variety is 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn are measured. The specific values are shown in Table 1.

[0092] Example 16

[0093] Polybutylene terephthalate with an intrinsic viscosity of 1.20 dl / g (core component) and polyethylene terephthalate with an intrinsic viscosity of 0.65 dl / g (sheath component) were selected for composite spinning. They were dried separately to make the moisture less than 100 ppm, then put into the spinning machine. The composite ratio was 50 / 50. An eccentric core-sheath type composite spinneret was used for spinning. The raw silk variety was controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers was 18, the minimum circumscribed circle diameter of the wave shape was 5.40 microns, and the distance between the center of gravity points of the core component and the sheath component was 7.2 microns.

[0094] The wound pre-oriented yarn was subjected to false twist processing with a hot needle false twist disc. The hot needle temperature was 90 °C, the hot box temperature was 180 °C, and the stretching speed was 500 m / min. The final DTY variety was 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn were measured. The specific values are shown in Table 1.

[0095] Example 17

[0096] Polybutylene terephthalate with an intrinsic viscosity of 1.50 dl / g (core component) and polyethylene terephthalate with an intrinsic viscosity of 0.50 dl / g (sheath component) were selected for composite spinning. They were dried separately to make the moisture less than 100 ppm, then put into the spinning machine. The composite ratio was 50 / 50. An eccentric core-sheath type composite spinneret was used for spinning. The raw silk variety was controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers was 18, the minimum circumscribed circle diameter of the wave shape was 1.50 microns, and the distance between the center of gravity points of the core component and the sheath component was 7.2 microns.

[0097] The wound pre-oriented yarn was subjected to false twist processing with a hot needle false twist disc. The hot needle temperature was 90 °C, the hot box temperature was 180 °C, and the stretching speed was 500 m / min. The final DTY variety was 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the false-twisted DTY yarn were measured. The specific values are shown in Table 1.

[0098] Comparative Example 1

[0099] Polybutylene terephthalate with an intrinsic viscosity of 1.20 dl / g (core component) and polyethylene terephthalate with an intrinsic viscosity of 0.65 dl / g (sheath component) were selected for composite spinning. They were dried separately to make the moisture less than 100 ppm, then put into the spinning machine. The composite ratio was 50 / 50. An eccentric core-sheath type composite spinneret was used for spinning. The raw silk variety was controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers was 18, the minimum circumscribed circle diameter of the wave shape was 1.50 microns, and the distance between the center of gravity points of the core component and the sheath component was 1.8 microns.

[0100] The wound pre-oriented yarn is subjected to false twist processing with a hot needle false twist disc. The hot needle temperature is 90 °C, the hot box temperature is 180 °C, and the stretching speed is 500 m / min. The final DTY variety is 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the DTY yarn after false twist are measured. The specific values are shown in Table 1.

[0101] Since the ratio of the distance between the center of gravity points of the core component and the sheath component to the fiber cross-sectional diameter is too small, the elasticity of the final fiber is poor.

[0102] Comparative Example 2

[0103] Polybutylene terephthalate (core component) with an intrinsic viscosity of 1.20 dl / g and cationic polyethylene terephthalate (sheath component) with an intrinsic viscosity of 0.50 dl / g are selected for composite spinning. They are dried separately to make the moisture less than 100 ppm, and then put into the spinning machine. The composite ratio is 50 / 50. An eccentric core-sheath type composite spinneret is used for spinning. The original yarn variety is controlled to be 100 dtex / 36F. The number of waves at the junction of the two polymers is 18, the diameter of the smallest circumscribed circle of the wave shape is 1.50 microns, and the distance between the center of gravity points of the core component and the sheath component is 16.2 microns.

[0104] The wound pre-oriented yarn is subjected to false twist processing with a hot needle false twist disc. The hot needle temperature is 90 °C, the hot box temperature is 180 °C, and the stretching speed is 500 m / min. The final DTY variety is 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the DTY yarn after false twist are measured. The specific values are shown in Table 1.

[0105] Since the ratio of the distance between the center of gravity points of the core component and the sheath component to the fiber cross-sectional diameter is too large, the elasticity of the final fiber is poor.

[0106] Comparative Example 3

[0107] Polybutylene terephthalate (core component) with an intrinsic viscosity of 1.20 dl / g and cationic polyethylene terephthalate (sheath component) with an intrinsic viscosity of 0.50 dl / g are selected for composite spinning. They are dried separately to make the moisture less than 100 ppm, and then put into the spinning machine. The composite ratio is 50 / 50. An eccentric core-sheath type composite spinneret is used for spinning. The original yarn variety is controlled to be 100 dtex / 36F. The distance between the center of gravity points of the core component and the sheath component is 7.2 microns.

[0108] The wound pre-oriented yarn is subjected to false twist processing with a hot needle false twist disc. The hot needle temperature is 90 °C, the hot box temperature is 180 °C, and the stretching speed is 500 m / min. The final DTY variety is 56 dtex / 36F. The strength, elongation, and elastic elongation rate of the DTY yarn after false twist are measured. The specific values are shown in Table 1.

[0109] This comparative example is a conventional eccentric core-sheath composite fiber, and the contact surface between the core component and the sheath component is not wavy, resulting in poor spinnability during fiber preparation.

[0110]

Claims

1. The eccentric core-sheath composite fiber mainly contains a core component and a sheath component with different intrinsic viscosities, and is characterized in that: The ratio of the distance between the centroid point of the core component and the centroid point of the sheath component to the cross-sectional diameter of the composite fiber is 0.2 to 0.8; the contact surface between the core component and the sheath component on the cross-section of the composite fiber is wavy.

2. The eccentric core-sheath composite fiber according to claim 1, wherein: The number of the wavy shapes is more than 8.

3. The eccentric core-sheath composite fiber according to claim 1 or 2, characterized in that: The ratio of the diameter of the minimum circumscribed circle of the wavy shape to the cross-sectional diameter of the fiber is 0.01 to 0.

20.

4. The eccentric core-sheath composite fiber according to claim 1 or 2, characterized in that: The difference in intrinsic viscosity between the core component and the sheath component is 0.30 to 0.80 dl / g.

5. The eccentric core-sheath composite fiber according to claim 1 or 2, characterized in that: The core component and the sheath component are respectively selected from polyester, polyolefin or polyamide.

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