Split-type composite fiber

Abstract

A split type composite fiber containing a polymer A and a polymer B, in a fiber cross section, the polymer A is continuously distributed, the polymer B is split into large split pieces and small split pieces, and all split pieces are exposed on the fiber surface; the single fiber cross section has 1 to 3 maximum split pieces with the same area, and more than 2 small split pieces with smaller area than the maximum split piece; the area of the single maximum split piece accounts for 7.5 to 70.0% of the fiber cross section area, and the area of the single maximum split piece is more than 2 times the area of the single small split piece. The initial split rate of the split type composite fiber is low, and after physical treatment such as hot water without using chemical agents, it can be effectively split, and after splitting, it is fluffy and soft.

Description

Technical Field

[0001] This invention relates to a segmented composite fiber, specifically, to a segmented composite fiber composed of polymer A and polymer B, wherein polymer B is divided into large segments and small segments, and has a low initial fiber opening rate and a high fiber opening rate after boiling water treatment. Background Technology

[0002] Synthetic fibers, represented by polyester and polyamide, occupy an important position in various fields such as clothing, home decoration, vehicle interiors, and industrial materials due to their excellent flexibility, elastic recovery, abrasion resistance, and alkali resistance. In recent years, the market has continuously launched differentiated fibers with various functions. Among them, artificially synthesized split fibers and raw cotton that can be used for imitation cotton and industrial applications are a major research and development focus.

[0003] Currently, the technology of obtaining fluffy and soft fibers by opening segmented composite fibers with cross-sections of parallel, radial, or hollow rings formed from two polymers through physical or chemical methods has been widely studied. Taiwan Patent TW200825225A discloses a segmented composite long fiber and a nonwoven fabric composed of segmented composite long fibers. It mainly uses a propylene-based polymer with an MFR greater than or equal to 40g / 10min at a load of 2160g and 230℃, and high-pressure low-density polyethylene, with the propylene-based polymer and high-pressure low-density polyethylene partially interconnected to form segmented composite long fibers. The fiber opening process using high-pressure water jets improves the segmentation properties. However, the conditions for fiber opening using high-pressure water jets are quite demanding, increasing the cost. Chinese Patent CN101646813A discloses a segmented composite fiber composed of a polyamide composition and a fiber-forming polymer with no affinity for the polyamide composition. Opening this fiber using low-concentration benzyl alcohol or without a swelling agent shows good fiber cutting performance. However, it mainly utilizes aliphatic dicarboxylic acids and aromatic diamines as the main structural units to form polyamides with high shrinkage properties, which requires high polymer performance and is not suitable for the fiber opening process of split fibers formed by ordinary conventional polymers. Summary of the Invention

[0004] The purpose of this invention is to provide a split composite fiber with a low initial fiber opening rate, which can be effectively opened by physical methods such as hot water without the use of chemical agents, and is fluffy and soft after opening.

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

[0006] A segmented composite fiber contains polymer A and polymer B. On the cross-section of the fiber, polymer A is continuously distributed, and polymer B is divided into large and small segments, with all segments exposed on the fiber surface. The cross-section of each single fiber has 1 to 3 largest segments of equal area and 2 or more smaller segments with areas smaller than the largest segments. The area of ​​a single largest segment accounts for 7.5 to 70.0% of the fiber's cross-sectional area, and the area of ​​a single largest segment is more than twice the area of ​​a single smaller segment.

[0007] The perimeter of the single largest segment is L1, and the contact length between the single largest segment and polymer A is L2, with L2 / L1 preferably being 45-80%.

[0008] The angle between the tangent at the intersection of the largest segment and the edge of the fiber cross-section is preferably above 90°.

[0009] After the composite fiber is treated with boiling water, the shrinkage rate of polymer A is preferably greater than that of polymer B, and the difference is more than 5%.

[0010] The difference in solubility parameters between polymer A and polymer B is preferably 1.0 to 10.8 J. 1 / 2 / cm 3 / 2 .

[0011] The polymers A and B are preferably polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polypropylene, polyamide-6, polyamide-56, polyamide-66, or polyamide-610, respectively.

[0012] The area ratio of polymer A to polymer B on the cross-section of the composite fiber is preferably 70:30 to 30:70.

[0013] The initial fiber opening rate of the composite fiber is preferably below 5%, and the fiber opening rate after boiling water treatment is preferably above 90%.

[0014] The composite fiber is preferably a short fiber with an initial fiber opening rate of less than 5%.

[0015] The water absorption rate of polymer A is preferably below 1.5%.

[0016] This invention improves fiber-opening performance by designing the cross-section of segmented composite fibers to prioritize the opening of the largest segment, creating movable space that drives the opening of smaller segment pieces. Furthermore, in the preferred embodiment, controlling the ratio of the contact length to the perimeter and the contact angle of the largest segment within the fiber avoids an "anchoring effect," further facilitating fiber opening. Moreover, by utilizing differences in polymer solubility parameters and controlling the water absorption rate of polymer A, the initial fiber-opening rate is kept below 5% for both segmented composite long and short fibers, and the fiber-opening rate after boiling water treatment exceeds 90%. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the cross-section of the segmented composite fiber described in this invention.

[0018] Figure 2 This is a schematic diagram of the cross-section of the segmented composite fiber described in this invention.

[0019] Figure 3 This is a schematic diagram of the cross-section of the segmented composite fiber described in this invention.

[0020] Figure 4 This is a schematic diagram of the cross-section of the segmented composite fiber in embodiments 01-06, 14 and 18 of the present invention.

[0021] Figure 5 This is a schematic cross-sectional view of the segmented composite fiber in Embodiment 07 of the present invention.

[0022] Figure 6 This is a schematic cross-sectional view of the segmented composite fiber in Embodiment 08 of the present invention.

[0023] Figure 7 This is a schematic cross-sectional view of the segmented composite fiber in Embodiment 09 of the present invention.

[0024] Figure 8 This is a schematic cross-sectional view of the segmented composite fiber in Embodiment 10 of the present invention.

[0025] Figure 9 This is a schematic cross-sectional view of the segmented composite fiber in Embodiment 11 of the present invention.

[0026] Figure 10 This is a schematic diagram of the cross-section of the segmented composite fiber in Embodiment 12 of the present invention.

[0027] Figure 11 This is a schematic cross-sectional view of the segmented composite fiber in Embodiment 13 of the present invention.

[0028] Figure 12 This is a schematic cross-sectional view of the segmented composite fiber in Embodiment 15 of the present invention.

[0029] Figure 13 This is a schematic cross-sectional view of the segmented composite fiber in Embodiment 16 of the present invention.

[0030] Figure 14 This is a schematic cross-sectional view of the segmented composite fiber in Embodiment 17 of the present invention.

[0031] Figure 15 This is a schematic cross-sectional view of the segmented composite fiber in Embodiment 19 of the present invention.

[0032] Figure 16 This is a schematic cross-sectional view of the segmented composite fiber in Embodiment 20 of the present invention.

[0033] Figure 17 This is a schematic cross-sectional view of the segmented composite fiber of Comparative Example 01 of the present invention.

[0034] Figure 18 This is a schematic cross-sectional view of the segmented composite fiber of Comparative Example 02 of the present invention.

[0035] Figure 19 This is a schematic cross-sectional view of the segmented composite fiber of Comparative Example 03 of the present invention.

[0036] Figure 20 This is a schematic cross-sectional view of the segmented composite fiber of Comparative Example 04 of the present invention.

[0037] Figures 1-3 In the diagram, S represents the total area of ​​the fiber cross-section, S1 represents the area of ​​the single largest segment on the fiber cross-section, S2 represents the area of ​​the single small segment on the fiber cross-section, L1 represents the perimeter of the single largest segment, and L2 represents the contact length between the single largest segment and polymer A. Detailed Implementation

[0038] The cross-section of the segmented composite fiber of the present invention contains two polymers, namely polymer A and polymer B. Polymer A is continuously distributed, and polymer B is divided into large segment blocks and small segment blocks, and all segment blocks are exposed on the fiber surface.

[0039] In the melt spinning process of segmented composite fibers, the segmented blocks formed by polymer B are arranged on the outer side of the fiber. After being spun from the spinneret, they are preferentially cooled and then easily oriented under the traction of a certain spinning speed. This results in a high boiling water shrinkage rate of the segmented blocks in the segmented composite fiber, making it difficult to generate a shrinkage difference with polymer A, which is detrimental to the fiber opening of the segmented composite fiber. Therefore, this invention sets the polymer B into 1 to 3 largest segmented blocks of the same area and 2 or more smaller segmented blocks with an area smaller than the largest segmented block. The largest segmented block is less likely to align with the smaller segmented blocks during melt spinning, thus maintaining a sufficient shrinkage difference between the largest segmented block and polymer A, making it easy to segment. The largest segmented block can serve as the starting point for fiber opening of the segmented composite fiber during boiling water treatment. After the largest segmented block detaches, it creates more movable space for polymer A, thereby promoting the fiber opening of the smaller segmented blocks.

[0040] The cross-section of the segmented composite fiber has 1 to 3 largest segmented blocks of the same area, with the area of ​​a single largest segmented block accounting for 7.5% to 70.0% of the fiber's cross-sectional area. When there are more than 3 largest segmented blocks, the cross-sectional area is too large, resulting in high fineness of the fibers formed after opening, which is detrimental to providing a fluffy and soft feel. Furthermore, although the largest segmented blocks are relatively beneficial for opening, they also lead to a high initial fiber opening rate, affecting the throughput of subsequent processing. When the area of ​​a single largest segmented block is less than 7.5% of the fiber's cross-sectional area, it is not conducive to fiber opening; when the area of ​​a single largest segmented block is greater than 70.0% of the fiber's cross-sectional area, the fineness of the monofilaments in the single largest segmented block is high, which is also detrimental to providing a fluffy and soft feel. After boiling water treatment, to obtain excellent fiber opening performance and a fluffy feel, this invention preferably specifies that the area of ​​a single largest segmented block accounts for 10.0% to 30.0% of the fiber's cross-sectional area.

[0041] In addition to 1 to 3 largest segmented blocks with the same area, the cross-section of the segmented composite fiber also has 2 or more smaller segmented blocks with an area smaller than the largest segmented block. That is, all segmented blocks with an area smaller than the largest segmented block are collectively referred to as small segmented blocks. These small segmented blocks can be the same size or different sizes.

[0042] To make the distinction between the largest and smallest segments more pronounced, creating a clear sensory perception of size, and to maintain a high shrinkage differential between the largest segment and polymer A, as well as to provide a fluffy and soft feel, this invention also limits the area of ​​a single largest segment to at least twice the area of ​​a single smallest segment. While satisfying the area ratio, this invention does not particularly limit the area range of the smallest segments; the area of ​​a single small segment can be less than 7.5% of the total cross-sectional area of ​​the composite fiber, or it can be more than 7.5% of the total cross-sectional area of ​​the composite fiber.

[0043] As is well known, the frictional force between two components is positively correlated with the force applied to the contact surface and negatively correlated with the contact area. The smaller the ratio of the contact length L2 between the single largest segment block and polymer A to the perimeter L1 of the single largest segment block, the smaller the contact area between the single largest segment block and polymer A, which is more conducive to the opening of the segmented composite fiber. However, when the L2 / L1 ratio is too small, i.e., the contact area between the single largest segment block and polymer A is small, although it is beneficial for the opening of the segmented composite fiber through boiling water treatment, it also leads to a large initial opening rate of the composite fiber, thus affecting the subsequent preparation and processing permeability of textiles. Therefore, the L2 / L1 ratio of the present invention is preferably 45% to 80%, more preferably 45% to 70%.

[0044] Meanwhile, the angle between the largest segment and the fiber cross-section, i.e., the angle between the tangent at the intersection of the largest segment and the edge of the fiber cross-section, should not be too small. Otherwise, due to the "anchoring effect," the largest segment will not easily peel off from the space created by the shrinkage of polymer A during segmentation, resulting in the split composite fiber's fiber opening property not achieving the desired effect. Preferably, the angle between the largest segment and the tangent at the intersection of the largest segment and the edge of the fiber cross-section is 90° or greater.

[0045] To accelerate the separation of the largest segment from polymer A, it is preferable that the boiling water shrinkage rate of polymer A is greater than that of polymer B after boiling water treatment. After boiling water treatment, due to shrinkage stress, polymer A shrinks along the long axis of the composite fiber. According to the principle of constant mass and volume, polymer A expands in the cross-section of the composite fiber, increasing the opening to accommodate the largest segment and creating movable space for it, thereby achieving easy fiber opening. Preferably, the shrinkage rate of polymer A after boiling water treatment is greater than that of polymer B, with a difference of 5% or more, more preferably 10% or more.

[0046] Besides the shrinkage difference between polymer A and polymer B affecting the fiber-opening effect of the segmented composite fiber, the affinity between polymer A and polymer B also influences the fiber-opening effect and spinning performance. When the affinity between polymer A and polymer B is good, the segmented composite fiber is difficult to open, failing to achieve the desired fiber-opening effect; when the affinity between polymer A and polymer B is too poor, fiber opening and fuzzing are easily generated during melt spinning, resulting in poor processability and hindering production. This invention uses the absolute value of the difference in solubility parameters (SP values) between polymer A and polymer B (hereinafter referred to as the difference in SP values) to characterize the magnitude of their affinity; the smaller the difference in SP values, the better the affinity. To enable the segmented composite fiber to simultaneously achieve good fiber-opening effect and spinning performance, this invention preferably uses a difference in SP values ​​between polymer A and polymer B of 1.0 to 10.8 J. 1 / 2 / cm 3 / 2 More preferably 3.0–7.0 J 1 / 2 / cm3 / 2 .

[0047] This invention does not specifically limit the types of polymer A and polymer B, and they can be conventional polymers used in melt spinning, such as polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polybutylene terephthalate (PBT), polypropylene (PP), polyamide-4, polyamide-6, polyamide-56, polyamide-66, polyamide-510, or polyamide-610, etc. They can also be polymers that have undergone functional modifications such as particle addition or shrinkage property modification.

[0048] Under otherwise identical conditions, if polymer B occupies too little area in the cross-section of the segmented composite fiber, it is not conducive to fiber opening; if polymer B occupies too much area, it is not conducive to providing a fluffy and soft hand feel. Therefore, the area ratio of polymer A to polymer B is preferably 70:30 to 30:70.

[0049] Unless otherwise specified, the segmented composite fiber of this invention can be either long or short fibers. When the segmented composite fiber is a long fiber, it can be made into soft-handed clothing or wiping cloths; when the segmented composite fiber is a short fiber, it can be made into non-woven fabrics, such as face masks with good liquid retention and a good fit to the skin. When the segmented composite fiber is a short fiber, it satisfies both the requirement of small initial fiber opening to ensure the engineering passability of subsequent processing and the requirement of complete fiber opening only under boiling water conditions. Therefore, the composite fiber of this invention is preferably a composite short fiber.

[0050] For long fibers, meeting the distribution number and area of ​​the largest and smallest segmented blocks as defined in this invention achieves the preferred target of an initial fiber opening rate of less than 5%. However, for short fibers, due to the use of warm water baths for stretching during the filament cottonification (i.e., short fiber cutting) process, the hygroscopic swelling effect negatively impacts the initial fiber opening rate, resulting in a higher initial fiber opening rate for short fibers compared to long fibers with the same composition and structure. In considering how to reduce the initial fiber opening rate of short fibers, the inventors of this application started by identifying the cause of fiber opening during short fiber cutting. They discovered that the main problem lies in the water absorption and swelling phenomenon of polymer A, which creates movable space for the largest segmented block, causing it to detach from the main structure and increasing the initial fiber opening rate of the short fibers. This invention, by limiting the use of polymer A with low water absorption, avoids water absorption and swelling of polymer A during cutting, thus achieving a low initial fiber opening rate for short fibers. To obtain segmented composite short fibers with a low initial fiber opening rate, this invention preferably uses polymer A with a water absorption rate of less than 1.5%.

[0051] Regarding the water absorption rate of the preferred polymer A, a relatively satisfactory fiber opening rate can still be obtained when the fiber opening treatment is carried out by physical or chemical methods. This is mainly reflected in the fact that the fiber opening rate after boiling water treatment can reach more than 90%.

[0052] This invention, through meticulous design of the cross-section of the segmented composite fiber, uses a combination of the largest and smallest segmented blocks, while limiting the size relationship between the largest and smallest segmented blocks, so that the initial fiber opening rate of the segmented composite fiber is less than 5%, and it is easy to segment after boiling water treatment, with a fiber opening rate of more than 90%, which can meet the needs of various fluffy and soft fiber structures.

[0053] The testing method involved in this invention is as follows:

[0054] (1) Fiber cross-sectional area (S), area of ​​the largest segment (S1), area of ​​the smallest segment (S2)

[0055] The segmented composite fibers were wrapped with black or white carding strips and passed through small holes in a copper plate. The fibers were then cut with a blade to obtain the cross-section of the fiber bundle. The cross-section was observed and photographed using a Keyence VHX-6000 ultra-depth-of-field 3D fiber microscope, and the fiber cross-sectional area (S), the area of ​​the largest segment (S1), and the area of ​​the smallest segment (S2) were measured using a microscope measuring tool. The final result was the average value after 10 tests.

[0056] (2) Perimeter L1 of the largest segmented block and contact length L2

[0057] The segmented composite fibers were wrapped with black or white carding strips and passed through small holes in a copper plate. The fibers were then cut with a blade to obtain the cross-section of the fiber bundle. The cross-section was observed and photographed using a Keyence VHX-6000 ultra-depth-of-field 3D fiber microscope. The perimeter L1 of the largest single segment and the contact length L2 between the largest single segment and polymer A were measured using a microscope measuring tool. The final result was the average value after 10 tests.

[0058] (3) The angle between the tangent at the intersection of the largest segment and the edge of the fiber cross-section

[0059] The segmented composite fibers were wrapped with black or white carding strips and passed through small holes in a copper plate. The fibers were then cut with a blade to obtain the cross-section of the fiber bundle. The cross-section was observed and photographed using a Keyence VHX-6000 ultra-depth-of-field 3D fiber microscope, and the angle between the tangent at the intersection of the largest segment and the edge of the fiber cross-section was measured using a microscope measuring tool. The final result was the average of 10 tests.

[0060] (4) The difference in shrinkage rate after boiling water treatment

[0061] A 20cm (L0) length of segmented composite fiber was scourted at 40℃ (2g / L scouring agent + 0.6% NaOH aqueous solution) to remove surface contaminants such as oil and sizing agents. After boiling in a 98℃ water bath for 20 minutes to open the fiber, it was removed and air-dried naturally at 20℃ × 65% RH for 4 hours. Polymer B was separated from polymer A using tweezers, and the lengths of polymer B (L3) and polymer A (L4) were measured. The difference in shrinkage rates between polymer A and polymer B after boiling water treatment was calculated as [(L3-L4) / L0] × 100%. Ten samples were tested, and the final result was the average value.

[0062] (5) Solubility parameter (SP value)

[0063] The SP value (δp) of polymers is determined by turbidity titration. The specific steps are as follows:

[0064] A. After the split composite fiber is split, polymer A and polymer B are separated by tweezers;

[0065] B. Dissolve 0.5g of polymer A in 100ml of solvent (see table below for corresponding solvents) to obtain polymer A solution;

[0066] C. Use a pipette to draw 10 ml of polymer A solution into a test tube. First, titrate the polymer A solution in the test tube with n-pentane until a precipitate appears in the test tube. Shake the test tube to dissolve the precipitate. Then continue to add n-pentane until a precipitate that is difficult to dissolve by shaking appears. Record the volume of n-pentane used at this time, V1.

[0067] D. Continue titrating the polymer A solution that precipitated in step C with methanol. The original precipitate will gradually disappear during titration. After adding methanol, a new precipitate will appear. Shake the test tube to dissolve the precipitate. Continue adding methanol until a precipitate that is difficult to dissolve by shaking appears. Record the volume of methanol used at this time, V2.

[0068] E. Calculate the solubility parameter of polymer A using the following formula.

[0069] The lower limit of the solubility parameter of polymer A, δml, is given by: [V1 / (V1+V2)]×14.3.

[0070] The upper limit of the solubility parameter of polymer A, δmh, is given by: [V1 / (V1+V2)]×30.2.

[0071] The solubility parameter of polymer A is δp = δmh + δml.

[0072] In steps C and D above, the volume of liquid dispensed by the burette each time is 0.5 ml.

[0073] Take 0.5g of polymer B and repeat steps B to E to obtain the solubility parameters of polymer B.

[0074] When testing the solubility parameters of polymers A and B, 10 samples were taken for each polymer, and the final result was the average value.

[0075]

[0076] (6) Initial fiber opening rate and fiber opening rate after boiling water treatment

[0077] The split composite fiber was cut with a blade to obtain the cross-section of the fiber bundle. The fiber was then attached to conductive adhesive and sputtered with gold. The fiber cross-section was observed using a Hitachi TM3030plus scanning electron microscope (SEM). Twenty samples were tested, and the average value of the final results was taken as the initial fiber opening rate.

[0078] The split composite fibers were scoured at 40℃ (2g / L scouring agent + 0.6% NaOH aqueous solution) to remove surface contaminants such as oil and sizing agents. After being boiled in a 98℃ water bath for 20 minutes to open the fibers, they were removed and air-dried naturally at 20℃×65%RH for 4 hours. The fibers were then cut with a blade to obtain the cross-section of the fiber bundle. The fibers were then attached to conductive adhesive and sputter-coated with gold. The fiber cross-section was observed using a Hitachi TM3030plus scanning electron microscope (SEM). Twenty samples were tested, and the average value of the final results was used to obtain the fiber opening rate.

[0079] Fiber opening rate (%) = (Number of observed split pieces / Theoretical total number of split pieces) × 100%,

[0080] In the above formula, the observed number of segments refers to the number of segments that have completely separated from polymer A, and the theoretical total number of segments refers to the total number of all segments.

[0081] (7) Water absorption rate

[0082] After the split composite fibers were opened using the method described above, 0.5g of polymer A was separated using tweezers. The polymer A was dried in a vacuum oven at 105℃ for 8 hours, then conditioned at 20℃ × 65% RH for 24 hours. The saturated moisture content of the polymer was then tested using a differential pressure moisture analyzer, and the saturated moisture content, i.e., the water absorption rate, was determined. Ten samples were tested, and the average value was taken as the final result.

[0083] (8) Fluffiness

[0084] The split composite fibers were circularly knitted, and the circularly knitted fabric was scourted at 40℃ (2g / L scouring agent + 0.6% NaOH aqueous solution) to remove surface oils, sizing agents, and other contaminants. After fiber opening treatment by boiling in a 98℃ water bath for 20 minutes, the fabric was removed and naturally air-dried at 20℃ × 65% RH for 4 hours. The bulkiness of the fabric was evaluated according to the KES FB3 method. The higher the compression work (WC) value, the easier it is to compress, indicating that the sample is more bulky.

[0085] The advantages of the present invention will now be described in detail through the listed embodiments and comparative examples. The present invention is not limited to the embodiments described below.

[0086] Example 01:

[0087] The volume ratio of polymer A:PBT (intrinsic viscosity 1.10 dL / g, water absorption 0.4%, SP value 20.5 J) was 70:30. 1 / 2 / cm 3 / 2 Polymer B: Hydrophobically modified PET (polypropylene 2% compound, SP value 19.7J) and polymer B: 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with 1 large and 16 small sections on a composite spinneret. Other parameters of the FDY process are as follows: spinning temperature 278℃, spinning box temperature for PET 278℃, spinning box temperature for PBT 260℃, cooling temperature 20℃, cooling air velocity 0.8m / s, first roller speed 1200m / min, first roller temperature 80℃, second roller speed 2250m / min, second roller temperature 160℃.

[0088] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) shows an S1 / S ratio of 11%, an S1 / S2 ratio of 9.1, and an L2 / L1 ratio of 62%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge is 90°. The initial fiber opening rate is 1%. After heat treatment in a 98°C water bath for 20 minutes and natural drying at 20°C × 65% RH for 4 hours, the fiber opening rate is 76%. The difference in boiling water shrinkage between polymer A and polymer B is 11%. The compression work ratio of the circular knitted fabric after fiber opening is 0.383 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber is 2%.

[0089] Example 02:

[0090] The volume ratio of polymer A:PBT (intrinsic viscosity 1.10 dL / g, water absorption 0.4%, SP value 20.5 J) was 70:30. 1 / 2 / cm 3 / 2Polymer B: Hydrophobically modified PET (5% polypropylene compound, SP value 19.5J) and polymer B: 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with 1 large and 16 small sections on a composite spinneret. Other parameters of the FDY process are as follows: spinning temperature 278℃, spinning box temperature for PET 278℃, spinning box temperature for PBT 260℃, cooling temperature 20℃, cooling air velocity 0.8m / s, first roller speed 1200m / min, first roller temperature 80℃, second roller speed 2250m / min, second roller temperature 160℃.

[0091] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) shows an S1 / S ratio of 11%, an S1 / S2 ratio of 9.1, and an L2 / L1 ratio of 62%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge is 90°. The initial fiber opening rate is 1%. After heat treatment in a 98°C water bath for 20 minutes and natural drying at 20°C × 65% RH for 4 hours, the fiber opening rate is 90%. The difference in boiling water shrinkage between polymer A and polymer B is 11%. The compression work ratio of the circular knitted fabric after fiber opening is 0.433 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber is 2%.

[0092] Example 03:

[0093] The volume ratio of polymer A:PBT (intrinsic viscosity 1.10 dL / g, water absorption 0.4%, SP value 20.5 J) was 70:30. 1 / 2 / cm 3 / 2 Polymer B: PP (MFR 60 g / 10 min, SP value 16.8 J) and polymer B: PP (MFR 60 g / 10 min, SP value 16.8 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with 1 large and 16 small sections on a composite spinneret. Other parameters of the FDY process are as follows: spinning temperature 260℃, spinning box temperature for PP 250℃, spinning box temperature for PBT 260℃, cooling temperature 20℃, cooling air velocity 0.8m / s, first roller speed 1200m / min, first roller temperature 70℃, second roller speed 2250m / min, second roller temperature 160℃.

[0094] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) shows an S1 / S ratio of 11%, an S1 / S2 ratio of 9.1, and an L2 / L1 ratio of 62%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge is 90°. The initial fiber opening rate is 3%. After heat treatment in a 98°C water bath for 20 minutes and natural drying at 20°C × 65% RH for 4 hours, the fiber opening rate is 93%. The difference in boiling water shrinkage between polymer A and polymer B is 12%. The compression work ratio of the circular knitted fabric after fiber opening is 0.485 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber is 4%.

[0095] Example 04:

[0096] The polymer A:N6 (with a volume ratio of 70:30, relative viscosity ηr of 2.9, water absorption of 3.3%, and SP value of 27.6 J) was mixed. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with 1 large and 16 small sections on a composite spinneret. Other parameters of the FDY process are as follows: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0097] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) shows an S1 / S ratio of 11%, an S1 / S2 ratio of 9.1, and an L2 / L1 ratio of 62%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge is 90°. The initial fiber opening rate is 3%. After heat treatment in a 98°C water bath for 20 minutes and natural drying at 20°C × 65% RH for 4 hours, the fiber opening rate is 92%. The difference in boiling water shrinkage between polymer A and polymer B is 8%. The compression work ratio of the circular knitted fabric after fiber opening is 0.526 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber is 12%.

[0098] Example 05:

[0099] The polymer A:N6 (with a volume ratio of 70:30, relative viscosity ηr of 2.9, water absorption of 3.3%, and SP value of 27.6 J) was mixed. 1 / 2 / cm 3 / 2Polymer B: PP (MFR 60 g / 10 min, SP value 16.8 J) and polymer B: PP (MFR 60 g / 10 min, SP value 16.8 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with 1 large and 16 small sections on a composite spinneret. Other parameters of the FDY process are as follows: spinning temperature 275℃, spinning box temperature for PP 250℃, spinning box temperature for N6 275℃, cooling temperature 20℃, cooling air velocity 0.8m / s, first roller speed 1200m / min, first roller temperature 70℃, second roller speed 2450m / min, second roller temperature 160℃.

[0100] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) shows an S1 / S ratio of 11%, an S1 / S2 ratio of 9.1, and an L2 / L1 ratio of 62%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge is 90°. The initial fiber opening rate is 5%. After heat treatment in a 98°C water bath for 20 minutes and natural drying at 20°C × 65% RH for 4 hours, the fiber opening rate is 98%. The difference in boiling water shrinkage between polymer A and polymer B is 11%. The compression work ratio of the circular knitted fabric after fiber opening is 0.539 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber is 16%.

[0101] Example 06:

[0102] The volume ratio of polymer A:N610 (relative viscosity ηr 2.7, water absorption 1.0%, SP value 27.8 J) was 70:30. 1 / 2 / cm 3 / 2 Polymer B: PP (MFR 60 g / 10 min, SP value 16.8 J) and polymer B: PP (MFR 60 g / 10 min, SP value 16.8 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with 1 large and 16 small sections on a composite spinneret. Other parameters of the FDY process are as follows: spinning temperature 275℃, spinning box temperature for PP 250℃, spinning box temperature for N610 275℃, cooling temperature 20℃, cooling air velocity 0.8m / s, first roller speed 1200m / min, first roller temperature 70℃, second roller speed 2450m / min, second roller temperature 160℃.

[0103] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) shows an S1 / S ratio of 11%, an S1 / S2 ratio of 9.1, and an L2 / L1 ratio of 62%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge is 90°. The initial fiber opening rate is 7%. After heat treatment in a 98°C water bath for 20 minutes and natural drying at 20°C × 65% RH for 4 hours, the fiber opening rate is 98%. The difference in boiling water shrinkage between polymer A and polymer B is 11%. The compression work ratio of the circular knitted fabric after fiber opening is 0.527 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber is 11%.

[0104] Example 07:

[0105] The polymer A:N6 (with a volume ratio of 70:30, relative viscosity ηr of 2.9, water absorption of 3.3%, and SP value of 27.6 J) was mixed. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with one large and four small sections, and are produced according to the FDY process. Other parameters of the FDY process are: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0106] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) shows an S1 / S ratio of 10.0%, an S1 / S2 ratio of 2.0, and an L2 / L1 ratio of 58%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge is 105°. The initial fiber opening rate is 3%. After heat treatment in a 98°C water bath for 20 minutes and natural drying at 20°C × 65% RH for 4 hours, the fiber opening rate is 95%. The difference in boiling water shrinkage between polymer A and polymer B is 10%. The compression work ratio of the circular knitted fabric after fiber opening is 0.467 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber is 16%.

[0107] Example 08:

[0108] The polymer A:N6 (with a volume ratio of 70:30, relative viscosity ηr of 2.9, water absorption of 3.3%, and SP value of 27.6 J) was mixed. 1 / 2 / cm 3 / 2Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with two large and twelve small sections, and produced from the spinnerets through a composite spinneret. Other parameters of the FDY process are as follows: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0109] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) shows an S1 / S ratio of 9.0%, an S1 / S2 ratio of 9.0, and an L2 / L1 ratio of 61%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge is 91°. The initial fiber opening rate is 3%. After heat treatment in a 98°C water bath for 20 minutes and natural drying at 20°C × 65% RH for 4 hours, the fiber opening rate is 95%. The difference in boiling water shrinkage between polymer A and polymer B is 8%. The compression work ratio of the circular knitted fabric after fiber opening is 0.488 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber is 12%.

[0110] Example 09:

[0111] The polymer A:N6 (with a volume ratio of 70:30, relative viscosity ηr of 2.9, water absorption of 3.3%, and SP value of 27.6 J) was mixed. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with 3 large and 6 small sections on a composite spinneret. Other parameters of the FDY process are as follows: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0112] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) shows an S1 / S ratio of 7.5%, an S1 / S2 ratio of 6.0, and an L2 / L1 ratio of 61%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge is 91°. The initial fiber opening rate is 5%. After heat treatment in a 98°C water bath for 20 minutes and natural drying at 20°C × 65% RH for 4 hours, the fiber opening rate is 95%. The difference in boiling water shrinkage between polymer A and polymer B is 8%. The compression work ratio of the circular knitted fabric after fiber opening is 0.463 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber is 15%.

[0113] Comparative Example 01:

[0114] The polymer A:N6 (with a volume ratio of 70:30, relative viscosity ηr of 2.9, water absorption of 3.3%, and SP value of 27.6 J) was mixed. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with 18 small sections on a composite spinneret, following the FDY process. Other parameters of the FDY process are: spinning temperature 278℃, spinning box temperature for N6 275℃, spinning box temperature for PET 278℃, cooling temperature 20℃, cooling air velocity 0.8m / s, first roller speed 1200m / min, first roller temperature 80℃, second roller speed 2450m / min, second roller temperature 160℃.

[0115] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) shows that the area of ​​a single segment accounts for 1.0% of the fiber's cross-sectional area, the contact length between a single segment and polymer A accounts for 68% of the perimeter of the single segment, the angle between the tangents at the intersection of the segment and the fiber's cross-sectional edge is 90°, the initial fiber opening rate is 2%, and after heat treatment in a 98℃ water bath for 20 min and natural drying at 20℃ × 65% RH for 4 h, the fiber opening rate is 56%. The difference in boiling water shrinkage between polymer A and polymer B is 6%, and the compression work ratio of the circular knitted fabric after fiber opening is 0.319 gf.cm / cm2. The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber is 8%.

[0116] The lack of large segmented blocks resulted in a very low fiber opening rate after boiling water treatment.

[0117] Comparative Example 02:

[0118] A polymer A:N6 with a volume ratio of 50:50 (relative viscosity ηr 2.9, water absorption 3.3%, SP value 27.6 J) was used. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with 4 large and 8 small sections on a composite spinneret. Other parameters of the FDY process are as follows: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0119] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) showed an S1 / S ratio of 8.0%, an S1 / S2 ratio of 3.6, and an L2 / L1 ratio of 58%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge was 101°. The initial fiber opening rate was 13%. After heat treatment in a 98°C water bath for 20 minutes and natural drying at 20°C × 65% RH for 4 hours, the fiber opening rate was 95%. The difference in boiling water shrinkage between polymer A and polymer B was 8%. The compression work ratio of the circular knitted fabric after fiber opening was 0.312 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber was 15%.

[0120] The large number of maximum segmentation blocks resulted in excessively high initial fiber opening rates for both long and short fibers.

[0121] Comparative Example 03:

[0122] The polymer A:N6 (with a volume ratio of 70:30, relative viscosity ηr of 2.9, water absorption of 3.3%, and SP value of 27.6 J) was mixed. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2FDY filaments are produced by melt spinning through spinnerets with 1 large and 23 small sections, and produced according to the FDY process. Other parameters of the FDY process are: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0123] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) showed an S1 / S ratio of 4.0%, an S1 / S2 ratio of 3.5, and an L2 / L1 ratio of 63%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge was 91°. The initial fiber opening rate was 1%. After heat treatment in a 98°C water bath for 20 min and natural drying at 20°C × 65% RH for 4 h, the fiber opening rate was 63%. The difference in boiling water shrinkage between polymer A and polymer B was 7%. The compression work ratio of the circular knitted fabric after fiber opening was 0.331 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber was 9%.

[0124] Because the ratio of the largest single segment to the cross-sectional area of ​​the fiber is too small, it is not conducive to fiber opening, resulting in a low fiber opening rate after boiling water treatment.

[0125] Comparative Example 04:

[0126] The volume ratio of polymer A:N6 (relative viscosity ηr 2.9, water absorption 3.3%, SP value 27.6 J) was used. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with one large and three small sections, and are produced according to the FDY process. Other parameters of the FDY process are: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0127] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) showed an S1 / S ratio of 72.0%, an S1 / S2 ratio of 72.0, and an L2 / L1 ratio of 74%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge was 101°. The initial fiber opening rate was 2%. After heat treatment in a 98°C water bath for 20 min and natural drying at 20°C × 65% RH for 4 h, the fiber opening rate was 88%. The difference in boiling water shrinkage between polymer A and polymer B was 8%. The compression work ratio of the circular knitted fabric after fiber opening was 0.246 gf·cm / cm². The initial fiber opening rate of the short fiber prepared from the above segmented composite long fiber was 9%.

[0128] Because the ratio of a single segment to the cross-section of the fiber is too large, the fabric has poor fluffiness and a poor hand feel after the fibers are opened.

[0129] Example 10:

[0130] A polymer A:N6 with a volume ratio of 50:50 (relative viscosity ηr 2.9, water absorption 3.3%, SP value 27.6 J) was used. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with one large and four small sections, and are produced according to the FDY process. Other parameters of the FDY process are: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0131] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) showed an S1 / S ratio of 17.0%, an S1 / S2 ratio of 2.1, and an L2 / L1 ratio of 58%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge was 106°. The initial fiber opening rate was 3%. After heat treatment in a 98°C water bath for 20 min and natural drying at 20°C × 65% RH for 4 h, the fiber opening rate was 95%. The difference in boiling water shrinkage between polymer A and polymer B was 8%. The compression work ratio of the circular knitted fabric after fiber opening was 0.451 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber was 16%.

[0132] Example 11:

[0133] The volume ratio of polymer A:N6 (relative viscosity ηr 2.9, water absorption 3.3%, SP value 27.6 J) was 30:70. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with one large and four small sections, and are produced according to the FDY process. Other parameters of the FDY process are: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0134] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) showed an S1 / S ratio of 24.0%, an S1 / S2 ratio of 2.1, and an L2 / L1 ratio of 68%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge was 101°. The initial fiber opening rate was 2%. After heat treatment in a 98°C water bath for 20 min and natural drying at 20°C × 65% RH for 4 h, the fiber opening rate was 92%. The difference in boiling water shrinkage between polymer A and polymer B was 7%. The compression work ratio of the circular knitted fabric after fiber opening was 0.443 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber was 17%.

[0135] Example 12:

[0136] The polymer A:N6 (with a volume ratio of 70:30, relative viscosity ηr of 2.9, water absorption of 3.3%, and SP value of 27.6 J) was mixed. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with 1 large and 16 small sections on a composite spinneret. Other parameters of the FDY process are as follows: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0137] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) shows an S1 / S ratio of 9.0%, an S1 / S2 ratio of 8.1, and an L2 / L1 ratio of 80%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge is 101°. The initial fiber opening rate is 1%. After heat treatment in a 98°C water bath for 20 min and natural drying at 20°C × 65% RH for 4 h, the fiber opening rate is 75%. The difference in boiling water shrinkage between polymer A and polymer B is 8%. The compression work ratio of the circular knitted fabric after fiber opening is 0.482 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber is 8%.

[0138] Example 13:

[0139] A polymer A:N6 with a volume ratio of 50:50 (relative viscosity ηr 2.9, water absorption 3.3%, SP value 27.6 J) was used. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with one large and four small sections, and are produced according to the FDY process. Other parameters of the FDY process are: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0140] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) showed an S1 / S ratio of 18.0%, an S1 / S2 ratio of 2.3, and an L2 / L1 ratio of 74%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge was 73°. The initial fiber opening rate was 1%. After heat treatment in a 98°C water bath for 20 min and natural drying at 20°C × 65% RH for 4 h, the fiber opening rate was 58%. The difference in boiling water shrinkage between polymer A and polymer B was 8%. The compression work ratio of the circular knitted fabric after fiber opening was 0.379 gf·cm / cm². The initial fiber opening rate of the short fiber prepared from the above segmented composite long fiber was 6%.

[0141] Example 14:

[0142] A polymer A:N6 with a volume ratio of 70:30 (relative viscosity ηr 3.2, water absorption 3.4%, SP value 27.6 J) was used. 1 / 2 / cm 3 / 2Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with 1 large and 16 small sections on a composite spinneret. Other parameters of the FDY process are as follows: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0143] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) showed an S1 / S ratio of 11.0%, an S1 / S2 ratio of 9.1, and an L2 / L1 ratio of 63%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge was 90°. The initial fiber opening rate was 2%. After heat treatment in a 98°C water bath for 20 minutes and natural drying at 20°C × 65% RH for 4 hours, the fiber opening rate was 98%. The difference in boiling water shrinkage between polymer A and polymer B was 15%. The compression work ratio of the circular knitted fabric after fiber opening was 0.532 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber was 12%.

[0144] Example 15:

[0145] The polymer A:N610 (relative viscosity ηr 2.7, water absorption 1.5%, SP value 27.8 J) with a volume ratio of 50:50 was mixed. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with one large and four small sections, and are produced according to the FDY process. Other parameters of the FDY process are: spinning temperature 278℃, spinning box temperature for N610 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0146] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) showed an S1 / S ratio of 17.0%, an S1 / S2 ratio of 2.1, and an L2 / L1 ratio of 58%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge was 106°. The initial fiber opening rate was 0%. After heat treatment in a 98°C water bath for 20 min and natural drying at 20°C × 65% RH for 4 h, the fiber opening rate was 95%. The difference in boiling water shrinkage between polymer A and polymer B was 8%. The compression work ratio of the circular knitted fabric after fiber opening was 0.487 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber was 5%.

[0147] Example 16:

[0148] A polymer A:N6 with a volume ratio of 50:50 (relative viscosity ηr 2.9, water absorption 3.3%, SP value 27.6 J) was used. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with one large and four small sections, and are produced according to the FDY process. Other parameters of the FDY process are: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0149] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) shows an S1 / S ratio of 18.0%, an S1 / S2 ratio of 2.3, an L2 / L1 ratio of 45%, and an angle of 126° between the tangent at the intersection of the largest segment and the fiber cross-section edge. The initial fiber opening rate is 5%. After heat treatment in a 98°C water bath for 20 min and natural drying at 20°C × 65% RH for 4 h, the fiber opening rate is 97%. The difference in boiling water shrinkage between polymer A and polymer B is 8%. The compression work ratio of the circular knitted fabric after fiber opening is 0.489 gf.cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber is 12%.

[0150] Example 17:

[0151] A polymer A:N6 with a volume ratio of 50:50 (relative viscosity ηr 2.9, water absorption 3.3%, SP value 27.6 J) was used. 1 / 2 / cm 3 / 2Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with one large and four small sections, and are produced according to the FDY process. Other parameters of the FDY process are: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0152] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) shows an S1 / S ratio of 18.0%, an S1 / S2 ratio of 2.3, and an L2 / L1 ratio of 40%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge is 135°. The initial fiber opening rate is 7%. After heat treatment in a 98°C water bath for 20 minutes and natural drying at 20°C × 65% RH for 4 hours, the fiber opening rate is 97%. The difference in boiling water shrinkage between polymer A and polymer B is 8%. The compression work ratio of the circular knitted fabric after fiber opening is 0.474 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber is 16%.

[0153] Example 18:

[0154] The polymer A:N6 (with a volume ratio of 70:30, relative viscosity ηr of 2.4, water absorption of 3.4%, and SP value of 27.6 J) was mixed. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with 1 large and 16 small sections on a composite spinneret. Other parameters of the FDY process are as follows: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0155] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) showed an S1 / S ratio of 11.0%, an S1 / S2 ratio of 9.1, and an L2 / L1 ratio of 63%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge was 90°. The initial fiber opening rate was 2%. After heat treatment in a 98°C water bath for 20 min and natural drying at 20°C × 65% RH for 4 h, the fiber opening rate was 81%. The difference in boiling water shrinkage between polymer A and polymer B was 4%. The compression work ratio of the circular knitted fabric after fiber opening was 0.485 gf·cm / cm². The initial fiber opening rate of the short fiber prepared from the above segmented composite long fiber was 8%.

[0156] Example 19:

[0157] The volume ratio of polymer A:N6 (relative viscosity ηr 2.9, water absorption 3.3%, SP value 27.6 J) was used. 1 / 2 / cm 3 / 2 Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with one large and three small sections, and are produced according to the FDY process. Other parameters of the FDY process are: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0158] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) showed an S1 / S ratio of 70.0%, an S1 / S2 ratio of 42.0, and an L2 / L1 ratio of 73%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge was 101°. The initial fiber opening rate was 2%. After heat treatment in a 98°C water bath for 20 min and natural drying at 20°C × 65% RH for 4 h, the fiber opening rate was 90%. The difference in boiling water shrinkage between polymer A and polymer B was 8%. The compression work ratio of the circular knitted fabric after fiber opening was 0.253 gf·cm / cm². The initial fiber opening rate of the short fiber prepared from the above segmented composite long fiber was 9%.

[0159] Example 20:

[0160] A polymer A:N6 with a volume ratio of 80:20 (relative viscosity ηr 2.9, water absorption 3.3%, SP value 27.6 J) was used. 1 / 2 / cm 3 / 2Polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) and polymer B: PET (intrinsic viscosity 0.61 dL / g, SP value 21.0 J) 1 / 2 / cm 3 / 2 FDY filaments are produced by melt spinning through spinnerets with one large and four small sections, and are produced according to the FDY process. Other parameters of the FDY process are: spinning temperature 278℃, spinning box temperature for N6 is 275℃, spinning box temperature for PET is 278℃, cooling temperature is 20℃, cooling air velocity is 0.8m / s, first roller speed is 1200m / min, first roller temperature is 80℃, second roller speed is 2450m / min, second roller temperature is 160℃.

[0161] The cross-section of the prepared segmented composite long fiber (56T-18-FDY) showed an S1 / S ratio of 8.0%, an S1 / S2 ratio of 2.6, and an L2 / L1 ratio of 56%. The angle between the tangent at the intersection of the largest segment and the fiber cross-section edge was 102°. The initial fiber opening rate was 3%. After heat treatment in a 98°C water bath for 20 min and natural drying at 20°C × 65% RH for 4 h, the fiber opening rate was 90%. The difference in boiling water shrinkage between polymer A and polymer B was 7%. The compression work ratio of the circular knitted fabric after fiber opening was 0.448 gf·cm / cm². The initial fiber opening rate of the short fiber obtained from the above segmented composite long fiber was 16%.

[0162] Table 1

[0163]

[0164] Table 2

[0165]

[0166] Table 3

[0167]

[0168] Table 4

[0169]

Claims

1. A segmented composite fiber containing polymer A and polymer B, wherein polymer A is continuously distributed in the cross-section of the fiber, and polymer B is divided into largest and smallest segments, with all segments exposed on the fiber surface; characterized in that: The single fiber cross-section has 1 to 3 largest segmented blocks with the same area, and 2 or more smaller segmented blocks with areas smaller than the largest segmented blocks; the area of ​​a single largest segmented block accounts for 7.5 to 70.0% of the fiber cross-sectional area, and the area of ​​a single largest segmented block is more than twice the area of ​​a single smaller segmented block.

2. The segmented composite fiber according to claim 1, characterized in that: The perimeter of the single largest segment is L1, the contact length between the single largest segment and polymer A is L2, and the ratio of L2 to L1 is 45-80%.

3. The split-type composite fiber according to claim 1 or 2, characterized by: The angle between the tangent at the intersection of the largest segment and the edge of the fiber cross-section is greater than 90°.

4. The segmented composite fiber according to claim 1 or 2, characterized in that: After the composite fiber is treated with boiling water, the shrinkage rate of polymer A is greater than that of polymer B, and the difference is more than 5%.

5. The segmented composite fiber according to claim 1 or 2, characterized in that: The difference in solubility parameters between polymer A and polymer B is 1.0–10.8 J. 1 / 2 / cm 3 / 2 .

6. The segmented composite fiber according to claim 1 or 2, characterized in that: The polymers A and B are polyethylene terephthalate, propylene terephthalate, polybutylene terephthalate, polypropylene, polyamide-4, polyamide-6, polyamide-56, polyamide-66, polyamide-510, or polyamide-610, respectively.

7. The segmented composite fiber according to claim 1 or 2, characterized in that: The area ratio of polymer A to polymer B on the cross-section of the composite fiber is 70:30 to 30:

70.

8. The segmented composite fiber according to claim 1 or 2, characterized in that: The initial fiber opening rate of the composite fiber is below 5%, and the fiber opening rate after boiling water treatment is above 90%.

9. The segmented composite fiber according to claim 1 or 2, characterized in that: The composite fiber is a short fiber with an initial fiber opening rate of less than 5%.

10. The segmented composite fiber according to claim 9, characterized in that: The water absorption rate of polymer A is below 1.5%.

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