A self-curling hollow polyamide ester fiber for flake filling, its preparation method and application

Abstract

The present invention relates to the technical field of modified chemical fibers, in particular to a self-crimping hollow polyamide ester fiber for flake filling, its preparation method and application, including a main core layer and a skin layer that partially wraps the main core layer. After the skin layer partially wraps the main core layer, an eccentric structure with a hollow is formed, and heat setting is carried out in a tension-relaxed state, so that the skin layer and the main core layer generate self-crimping due to the difference in heat shrinkage performance. The skin layer is a polyamide ester polymer modified with cellulose nanocrystals, and the main core layer is an unmodified polyamide ester polymer, which has good fluffiness, resilience and warmth retention, is very suitable for the field of flake filling, and the moisture regain rate can reach more than 1.0%, which can reduce static electricity and improve comfort.

Description

Technical Field

[0001] The present invention relates to the technical field of modified chemical fibers, and in particular to a self-curling hollow polyamide ester fiber for flake filling, a preparation method thereof and an application thereof. Background Art

[0002] Polyamide ester fiber is a chemical fiber copolymerized from terephthalic acid, ethylene glycol and caprolactam. The CAS number applied for in the American Chemical Society is 25610-75-7. Yilun produced by Yizheng Chemical Fiber in China is a kind of polyamide ester fiber. Polyamide ester fiber has good cotton-like characteristics in terms of strength, hand feeling, appearance, etc., and is a super cotton-like fiber.

[0003] Conventional polyamide ester fibers have a relatively low modulus and very soft hand feeling. When used in fields such as flake filling, there is a certain lack of resilience. Moreover, although the moisture regain rate of polyamide ester fibers is higher than that of conventional polyester fibers, it only reaches about 0.5% - 0.6%. This moisture regain rate is much lower than that of natural fibers such as cotton and wool, and it is easy to generate static electricity.

[0004] CN 103952787 B discloses a soft polyamide ester fiber, which is prepared by the following steps: the modified polyamide ester melt enters the melt pipeline of the spinning device at a pressure of 3 - 8 MPa, is pressurized to 10 - 20 MPa by a booster pump, and then enters the spinning box through a filter to form a melt at 3 - 8 MPa and is spun at 240 - 295 °C, and the spinning speed is 800 - 1600 m / min. The above patent makes the breaking strength and modulus of the prepared soft polyamide ester fiber close to those of natural cotton fibers by preparing modified polyamide ester, using the melt spinning process, and strictly controlling the production process conditions. However, there is no characterization of improving the moisture regain rate, and this patent is a kind of soft polyamide ester fiber. When used in fields such as flake filling, its bulkiness, resilience and warmth retention have certain deficiencies. Summary of the Invention

[0005] Aiming at the deficiencies of the above-mentioned prior art, a self-curling hollow polyamide ester fiber for flake filling, a preparation method thereof and an application thereof are provided. It has good bulkiness, resilience and warmth retention, is very suitable for use in the field of flake filling, and the moisture regain rate can reach more than 1.0%, which can reduce static electricity and improve comfort.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is a self-curling hollow polyamide ester fiber for wadding filling, which includes a main core layer and a skin layer that partially wraps the main core layer. After the skin layer partially wraps the main core layer, an eccentric structure with a hollow is formed, and heat setting is carried out under a tension-relaxed state, so that the skin layer and the main core layer generate self-curling due to the difference in heat shrinkage performance. The skin layer is a polyamide ester polymer modified with cellulose nanocrystals, and the main core layer is an unmodified polyamide ester polymer.

[0007] For the above self-curling hollow polyamide ester fiber for wadding filling, the exposed area of the main core layer is not less than 30%.

[0008] For the above self-curling hollow polyamide ester fiber for wadding filling, the fiber fineness is 0.6 - 10 dtex.

[0009] For the above self-curling hollow polyamide ester fiber for wadding filling, its breaking strength is not less than 2.1 cN / dtex, and the moisture regain can reach more than 1.0%.

[0010] For the above self-curling hollow polyamide ester fiber for wadding filling, the polyamide ester polymer is formed by block copolymerization of terephthalic acid, ethylene glycol, and caprolactam, wherein the content of caprolactam is not less than 10%, the intrinsic viscosity is 0.60 - 0.85, and the melting point is 210 - 250 °C.

[0011] For the above self-curling hollow polyamide ester fiber for wadding filling, the polyamide ester polymer modified with cellulose nanocrystals is prepared by adding a certain amount of cellulose nanocrystals to the polyamide ester polymer. The diameter of the added cellulose nanocrystals is 10 - 20 nm, the length is 50 - 200 nm, and the addition amount of cellulose nanocrystals is 1.0% - 8.0%. The addition method is to fully mix the cellulose nanocrystal powder after anti-agglomeration surface treatment and the polyamide ester powder and then carry out melt granulation with a twin-screw extruder.

[0012] For the above self-curling hollow polyamide ester fiber for wadding filling, the particle size of the polyamide ester powder is 200 μm.

[0013] A preparation method of a self-curling hollow polyamide ester fiber for wadding filling includes the following steps:

[0014] (1) Prepare a polyamide ester polymer modified with cellulose nanocrystals: Add a certain amount of cellulose nanocrystals to the polyamide ester polymer. The diameter of the added cellulose nanocrystals is 10 - 20 nm, the length is 50 - 200 nm, and the addition amount of cellulose nanocrystals is 1.0% - 8.0%. The addition method is to fully mix the cellulose nanocrystal powder after anti-agglomeration surface treatment and the polyamide ester powder and then carry out melt granulation with a twin-screw extruder;

[0015] (2) Use a screw to send the cellulose nanocrystal-modified polyamide ester polymer to the skin spinneret holes. The skin spinneret holes are two linear spinneret holes. Send the unmodified polyamide ester polymer to the main core spinneret hole. The main core spinneret hole is a circular spinneret hole. The melt spinning temperature is 260 - 290 °C. The filaments ejected from the skin spinneret holes shrink due to the surface tension of the molten state when they just come out of the spinneret holes, contact and fuse with the filaments ejected from the circular spinneret holes. The filaments ejected from the skin spinneret holes also contact and fuse together at the ends, forming a certain hollow structure. At the same time, since the two linear spinneret holes cannot completely wrap the circular spinneret hole, a part of the filaments ejected from the circular spinneret hole is exposed on the fiber surface;

[0016] (3) After the spun polyamide ester fibers are drawn and oiled, they are subjected to relaxed setting at 160 °C for 60 s, and then cut to obtain self-crimping hollow polyamide ester fibers for flake filling.

[0017] In the above preparation method of the self-crimping hollow polyamide ester fibers for flake filling, the two linear spinneret holes are of equal width but unequal length. Their width is 10% - 30% of the diameter of the circular spinneret hole. The length of the longer linear spinneret hole is 1.5 - 3.0 times the diameter of the circular spinneret hole. The length of the shorter linear spinneret hole is 1.0 - 1.8 times the diameter of the circular spinneret hole. The minimum distance between the two linear spinneret holes and the circular spinneret hole is 1 - 3 times the width of the linear spinneret hole. The sum of the areas of the two linear spinneret holes is 50% - 200% of the area of the circular spinneret hole. The included angle between the two linear spinneret holes is an acute angle. The minimum distance between the two linear spinneret holes is 1 - 3 times the width of the linear spinneret hole.

[0018] An application of the self-crimping hollow polyamide ester fibers for flake filling in making flakes and performing flake filling.

[0019] The beneficial effects of the self-crimping hollow polyamide ester fibers for flake filling, its preparation method and application of the present invention are as follows: Based on the polyamide ester polymer formed by the block copolymerization of terephthalic acid, ethylene glycol, and caprolactam, the polyamide ester polymer is modified with cellulose nanocrystals. It is prepared by a semi-wrapped melt spinning composite spinning technology. The polyamide ester modified with fiber nanocrystals is used as the skin layer, and the unmodified polyamide ester is used as the main core layer, forming an eccentric structure with a hollow. And through the relaxed heat setting process, natural curling is generated due to the difference in the thermal shrinkage properties of the skin layer and the core layer. Moreover, the fiber has a certain hollow, with good bulkiness, resilience, and warmth retention. It is very suitable for the field of flake filling. At the same time, since the cellulose nanocrystals in the skin layer have relatively good hydrophilicity, the moisture regain of the polyamide ester fiber can be increased by more than one time, reaching more than 1.0%, which can reduce static electricity and improve comfort.

[0020] The diameter of the cellulose nanocrystals is 10 - 20 nm, and the length is 50 - 200 nm. Preferably, the length is 50 - 100 nm to ensure spinnability. The addition amount of the cellulose nanocrystals is 1.0% - 8.0%, preferably 1.0% - 5.0%. Based on this addition range, agglomeration will not occur due to too high a concentration.

[0021] The exposed area of the main core layer is not less than 30% to ensure the crimping effect of the fiber, and the stress limitation on the eccentric contraction is relatively small.

[0022] Its mechanical properties are similar to those of viscose and cotton. The breaking strength is not less than 2.1 cN / dtex, and the fiber fineness is 0.6 - 10 dtex. It can meet the usage requirements in fields such as home textiles and clothing. The elasticity and warmth retention are indicators corresponding to specific flake products, and can be increased by more than 30% - 80% based on the comparable polyester products. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the setting positions of the spinneret holes of the skin layer and the main core layer;

[0024] Figure 2 It is a schematic cross-sectional view of the self-crimping hollow polyamide ester fiber for flake filling. Detailed Embodiments

[0025] The present invention will be described in detail below with reference to the drawings and specific embodiments.

[0026] A self-crimping hollow polyamide ester fiber for flake filling includes a main core layer and a skin layer that partially wraps the main core layer. After the skin layer partially wraps the main core layer, an eccentric structure with a hollow is formed, and heat setting is performed in a tension-relaxed state, so that the skin layer and the main core layer generate self-crimping due to the difference in heat shrinkage properties. The skin layer is a polyamide ester polymer modified with cellulose nanocrystals, and the main core layer is an unmodified polyamide ester polymer.

[0027] Example 1

[0028] The same parts as in Example 1 will not be described again. The differences are as follows: The preparation method of the above self-crimping hollow polyamide ester fiber for flake filling includes the following steps:

[0029] (1) Preparation of cellulose nanocrystal-modified polyamide ester polymer: A certain amount of cellulose nanocrystals is added to the polyamide ester polymer. The added cellulose nanocrystals have a diameter of 10 nm and a length of 50 nm, and the addition amount of cellulose nanocrystals is 1.0%. The addition method is to fully mix the cellulose nanocrystal powder after anti-aggregation surface treatment and the polyamide ester powder, and then perform melt granulation with a twin-screw extruder. The polyamide ester polymer is formed by block copolymerization of terephthalic acid, ethylene glycol, and caprolactam, in which the content of caprolactam is 10%, the intrinsic viscosity is 0.60, and the melting point is 210 °C. The particle size of the polyamide ester powder is 200 μm.

[0030] (2) Using a screw to send the cellulose nanocrystal-modified polyamide ester polymer to the skin layer spinneret holes. The skin layer spinneret holes are two linear spinneret holes. Send the unmodified polyamide ester polymer to the main core layer spinneret hole. The main core layer spinneret hole is a circular spinneret hole 1. The melt spinning temperature is 260 °C. The filaments ejected from the skin layer spinneret holes shrink due to the surface tension of the molten state when they just come out of the spinneret holes, contact and fuse with the filaments ejected from the circular spinneret hole 1. The filaments ejected from the skin layer spinneret holes also contact and fuse together at the ends, forming a certain hollow structure. At the same time, since the two linear spinneret holes cannot completely wrap the circular spinneret hole, a part of the filaments ejected from the circular spinneret hole is exposed on the fiber surface;

[0031] (3) After the spun polyamide ester fibers are drawn and oiled, they are loosely set at 160 °C for 60 s, and then cut to obtain self-crimping hollow polyamide ester fibers for flake filling. During the process of loose heat setting, due to the high crystallinity and small heat shrinkage of the polyamide ester in the skin layer modified by cellulose nanocrystals, and the low crystallinity and large heat shrinkage of the unmodified main core layer polyamide ester component, and at the same time, since the fiber has an eccentric structure with the skin layer semi-wrapping the core layer, the fiber undergoes three-dimensional distortion during the loose heat setting process, forming a self-crimped state.

[0032] The two linear spinneret holes are of equal width but unequal length. Their width is 10% of the diameter of the circular spinneret hole. The length of the longer linear spinneret hole 2 is 1.5 times the diameter of the circular spinneret hole 1, and the length of the shorter linear spinneret hole 3 is 1.0 times the diameter of the circular spinneret hole. The minimum distance between the two linear spinneret holes and the circular spinneret hole 1 is 1 time the width of the linear spinneret hole. The sum of the areas of the two linear spinneret holes is 50% of the area of the circular spinneret hole 1. The included angle between the two linear spinneret holes is 30 °, and the minimum distance between the two linear spinneret holes is 1 time the width of the linear spinneret hole.

[0033] Example 2

[0034] The same parts as in Embodiment 1 will not be described in detail. The differences are as follows: The preparation method of the self-curling hollow polyamide ester fiber for flake filling includes the following steps:

[0035] (1) Prepare a polyamide ester polymer modified with cellulose nanocrystals: Add a certain amount of cellulose nanocrystals to the polyamide ester polymer. The diameter of the added cellulose nanocrystals is 15 nm, the length is 100 nm, and the addition amount of cellulose nanocrystals is 5.0%. The addition method is to fully mix the cellulose nanocrystal powder after anti-agglomeration surface treatment and the polyamide ester powder and then perform melt granulation with a twin-screw extruder; The polyamide ester polymer is formed by block copolymerization of terephthalic acid, ethylene glycol, and caprolactam, in which the caprolactam content is 30%, the intrinsic viscosity is 0.70, and the melting point is 230 °C.

[0036] (2) Send the polyamide ester polymer modified with cellulose nanocrystals to the skin layer spinneret holes by a screw. The skin layer spinneret holes are two linear spinneret holes. Send the unmodified polyamide ester polymer to the main core layer spinneret hole. The main core layer spinneret hole is a circular spinneret hole. The melt spinning temperature is 280 °C. The filaments ejected from the skin layer spinneret holes contract due to the surface tension of the molten state when they just come out of the spinneret holes, contact and fuse with the filaments ejected from the circular spinneret holes. The filaments ejected from the skin layer spinneret holes also contact and fuse together at the ends to form a certain hollow structure. At the same time, since the two linear spinneret holes cannot completely wrap the circular spinneret hole, a part of the filaments ejected from the circular spinneret hole is exposed on the fiber surface;

[0037] (3) After the spun polyamide ester fiber is drawn and oiled, it is loosely set at 160 °C for 60 s, and then cut to obtain the self-curling hollow polyamide ester fiber for flake filling.

[0038] The two linear spinneret holes are of equal width but unequal length. The width is 20% of the diameter of the circular spinneret hole. The length of the longer linear spinneret hole is 2.0 times the diameter of the circular spinneret hole. The length of the shorter linear spinneret hole is 1.5 times the diameter of the circular spinneret hole. The minimum distance between the two linear spinneret holes and the circular spinneret hole is 2 times the width of the linear spinneret hole. The sum of the areas of the two linear spinneret holes is 130% of the area of the circular spinneret hole. The included angle between the two linear spinneret holes is an acute angle. The minimum distance between the two linear spinneret holes is 2 times the width of the linear spinneret hole.

[0039] Embodiment 3

[0040] The same parts as in Embodiment 1 will not be described in detail. The differences are as follows: The preparation method of the self-curling hollow polyamide ester fiber for flake filling includes the following steps:

[0041] (1) Preparation of cellulose nanocrystal-modified polyamide ester polymer: A certain amount of cellulose nanocrystals is added to the polyamide ester polymer. The added cellulose nanocrystals have a diameter of 20 nm and a length of 200 nm, and the addition amount of cellulose nanocrystals is 8.0%. The addition method is to fully mix the cellulose nanocrystal powder after anti-agglomeration surface treatment and the polyamide ester powder, and then perform melt granulation with a twin-screw extruder; the polyamide ester polymer is formed by block copolymerization of terephthalic acid, ethylene glycol, and caprolactam, wherein the caprolactam content is 40%, the intrinsic viscosity is 0.85, and the melting point is 250 °C.

[0042] (2) Sending the cellulose nanocrystal-modified polyamide ester polymer to the skin layer spinneret holes by a screw. The skin layer spinneret holes are two linear spinneret holes, and the unmodified polyamide ester polymer is sent to the main core layer spinneret hole. The main core layer spinneret hole is a circular spinneret hole. The melt spinning temperature is 290 °C. The filaments ejected from the skin layer spinneret holes contract due to the surface tension of the molten state when they just come out of the spinneret holes, contact and fuse with the filaments ejected from the circular spinneret holes. The filaments ejected from the skin layer spinneret holes also contact and fuse together at the ends, forming a certain hollow structure. At the same time, since the two linear spinneret holes cannot completely wrap the circular spinneret hole, a part of the filaments ejected from the circular spinneret hole is exposed on the fiber surface;

[0043] (3) After the spun polyamide ester fibers are drawn and oiled, they are subjected to relaxed setting at 160 °C for 60 s, and then cut to obtain self-crimping hollow polyamide ester fibers for flake filling.

[0044] The two linear spinneret holes are of equal width but unequal length. Their width is 10% of the diameter of the circular spinneret hole. The length of the longer linear spinneret hole 2 is 1.5 times the diameter of the circular spinneret hole 1, and the length of the shorter linear spinneret hole 3 is 1.0 times the diameter of the circular spinneret hole. The minimum distance between the two linear spinneret holes and the circular spinneret hole 1 is 1 time the width of the linear spinneret hole. The sum of the areas of the two linear spinneret holes is 50% of the area of the circular spinneret hole 1. The included angle between the two linear spinneret holes is 30 °, and the minimum distance between the two linear spinneret holes is 1 time the width of the linear spinneret hole.

[0045] Example 4

[0046] The same parts as in Example 1 will not be described again. The differences are as follows: The preparation method of the self-crimping hollow polyamide ester fibers for flake filling described above includes the following steps:

[0047] (1) Selecting polyamide ester slices with a caprolactam segment content of 10% and an intrinsic viscosity of 0.68 as a substrate; selecting cellulose nanocrystals with an average diameter of 20 nm and a length of 50 nm as a modifier, weighing 5 parts of the modified cellulose nanocrystals and 95 parts of polyamide ester powder with a particle size of 200 μm, mixing them thoroughly, and then granulating them with a twin-screw extruder to obtain cellulose nanocrystal-modified polyamide ester;

[0048] (2) delivering the polyamide ester melt modified by cellulose nanocrystals to two straight-line spinnerets, delivering the unmodified polyamide ester melt to the circular spinneret, and then performing melt spinning; in the spinneret, the diameter of the circular spinneret is 0.4 mm, the width of the straight-line spinneret is 0.1 mm, the length of the shorter straight-line spinneret is 0.6 mm, the length of the longer spinneret is 0.9 mm, the angle between the two straight-line spinnerets is 60 degrees, the minimum spacing between the two straight-line spinnerets and the circular spinneret is 0.15 mm, and the minimum spacing between the two straight-line spinnerets is 0.20 mm;

[0049] (3) The spun polyamide ester fiber is stretched and oiled, loosely shaped at 160° C. for 60 seconds, and then cut to obtain a self-curling hollow polyamide ester fiber for flake filling.

[0050] The self-curling hollow polyamide polyester fiber for flake filling prepared by the above embodiment has a fiber fineness of 0.6-10 dtex, and its mechanical properties are similar to those of viscose and cotton, and the breaking strength is not less than 2.1 cN / dtex, which can meet the use requirements in the fields of home textiles and clothing. Since the cellulose nanocrystals in the cortex have relatively good hydrophilicity, the regain rate can reach more than 1.0%, which can reduce static electricity and improve comfort. The exposed area of ​​the main core layer is not less than 30%, which ensures the curling effect of the fiber, and the stress limit of eccentric shrinkage is small. Elasticity and warmth retention are indicators corresponding to specific flake products, which can be increased by more than 30%-80% according to the benchmark polyester product.

[0051] Cellulose nanocrystal powders with anti-agglomeration surface treatment are prior art, such as acetylation modification, cationic hydrophobic modification, cationic hydrophilic modification, alkylation modification, polyacrylic acid grafting modification, etc., which will not be repeated here. The present application prefers acetylated modified cellulose nanocrystals.

[0052] Example 5

[0053] The self-curling hollow polyamide polyester fiber for flake filling produced by the present invention has greatly improved performance compared with traditional polyamide polyester fibers, and the moisture regain can reach more than 1.0%. In addition, due to the hollow structure in a self-curling form, it has relatively good fluffiness, resilience and warmth retention. It is a high-quality fiber raw material for making flakes and can be used for making flakes and flake filling.

[0054] Certainly, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those of ordinary skill in the art within the scope of the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. A self-curling hollow polyamide ester fiber for wadding filling, characterized in that: It includes a main core layer and a skin layer that partially wraps the main core layer. After the skin layer partially wraps the main core layer, an eccentric structure with a hollow is formed. Through heat setting under a tension-relaxed state, self-curling occurs due to the difference in thermal shrinkage performance between the skin layer and the main core layer. The skin layer is a polyamide ester polymer modified with cellulose nanocrystals, and the main core layer is an unmodified polyamide ester polymer; the exposed area of the main core layer is not less than 30%; the fiber fineness is 0.6 - 10 dtex; Its breaking strength is not less than 2.1 cN / dtex, and the moisture regain can reach more than 1.0%; the polyamide ester polymer is formed by block copolymerization of terephthalic acid, ethylene glycol, and caprolactam, where the caprolactam content is not less than 10%, the intrinsic viscosity is 0.60 - 0.85, and the melting point is 210 - 250 °C.

2. The self-crimping hollow polyamide ester fiber for wadding filling according to claim 1, characterized in that, The polyamide ester polymer modified with cellulose nanocrystals is prepared by adding a certain amount of cellulose nanocrystals to the polyamide ester polymer. The added cellulose nanocrystals have a diameter of 10 - 20 nm and a length of 50 - 200 nm, and the addition amount of cellulose nanocrystals is 1.0% - 8.0%. The addition method is to fully mix the cellulose nanocrystal powder after anti-agglomeration surface treatment and the polyamide ester powder and then perform melt granulation with a twin-screw extruder.

3. The self-crimping hollow polyamide ester fiber for wadding filling according to claim 2, characterized in that, The particle size of the polyamide ester powder is 200 μm.

4. The preparation method of the self-curling hollow polyamide ester fiber for wadding filling according to any one of claims 1-3, characterized in that: It includes the following steps: (1) Prepare a polyamide ester polymer modified with cellulose nanocrystals: Add a certain amount of cellulose nanocrystals to the polyamide ester polymer. The added cellulose nanocrystals have a diameter of 10 - 20 nm and a length of 50 - 200 nm, and the addition amount of cellulose nanocrystals is 1.0% - 8.0%. The addition method is to fully mix the cellulose nanocrystal powder after anti-agglomeration surface treatment and the polyamide ester powder and then perform melt granulation with a twin-screw extruder; (2) Use a screw to send the polyamide ester polymer modified with cellulose nanocrystals to the skin layer spinneret holes. The skin layer spinneret holes are two linear spinneret holes, and send the unmodified polyamide ester polymer to the main core layer spinneret hole. The main core layer spinneret hole is a circular spinneret hole. The melt spinning temperature is 260 - 290 °C. The filaments ejected from the skin layer spinneret holes shrink due to the surface tension of the molten state when they just come out of the spinneret holes, contact and fuse with the filaments ejected from the circular spinneret holes. The filaments ejected from the skin layer spinneret holes also contact and fuse together at the ends, forming a certain hollow structure. At the same time, since the two linear spinneret holes cannot completely wrap the circular spinneret hole, part of the filaments ejected from the circular spinneret hole are exposed on the fiber surface; (3) After the spun polyamide ester fibers are drawn and oiled, they are loosely set at 160 °C for 60 s, and then cut to obtain self-curling hollow polyamide ester fibers for flake filling.

5. The preparation method of the self-curling hollow polyamide ester fiber for wadding filling according to claim 4, characterized in that, The two linear spinneret holes are of the type with equal width but unequal length. The width is 10% - 30% of the diameter of the circular spinneret hole. The length of the longer linear spinneret hole is 1.5 - 3.0 times the diameter of the circular spinneret hole, and the length of the shorter linear spinneret hole is 1.0 - 1.8 times the diameter of the circular spinneret hole. The minimum distance between the two linear spinneret holes and the circular spinneret hole is 1 - 3 times the width of the linear spinneret hole. The sum of the areas of the two linear spinneret holes is 50% - 200% of the area of the circular spinneret hole. The included angle between the two linear spinneret holes is an acute angle, and the minimum distance between the two linear spinneret holes is 1 - 3 times the width of the linear spinneret hole.

6. Application of the self - crimping hollow polyamide ester fiber for flake filling according to any one of claims 1 - 3 in the production of flakes and in flake filling.

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