Core-sheath composite fiber, and application thereof, and profiled fiber

Abstract

The present invention relates to a kind of core-sheath composite fiber and the profiled fiber and fabric formed by it.The sheath component of the core-sheath composite fiber is easily soluble polyester, and the core component is annular with an opening on the cross section of single fiber, the opening angle is 10°-60°, and the contact of the core component and the sheath component is wavy line shape;The profiled fiber formed by the weight reduction of the core-sheath composite fiber has continuous grooves distributed along the fiber axis on the outer surface.The core-sheath composite fiber of the present invention can be used to prepare fabric, and has excellent loftiness, lightness and water absorption and waterproof properties after weight reduction.

Description

Technical Field

[0001] This invention relates to a core-sheath composite fiber with excellent bulkiness and lightweight properties after weight reduction, which can be applied to waterproof and absorbent fabrics, as well as irregularly shaped fibers formed from the core-sheath composite fiber. Background Technology

[0002] With the rapid development of science and technology and the continuous improvement of people's living standards, people's requirements for the practical functions of clothing have gone beyond simply covering the body and keeping warm. They now encompass a wide range of needs: from comfort to health, from safety to hygiene, from ease of storage and handling to suitability for different climates and environments, and from accommodating the pace of modern life to adapting to modern lifestyles. Especially in recent years, with unpredictable climate changes and large daily temperature differences, people often experience frequent illnesses due to not changing their clothing in a timely manner. This places higher demands on the heat-insulating and temperature-regulating functions, as well as the comfort of clothing.

[0003] Winter clothing often uses thicker fabrics, resulting in a heavy feel and hindering movement. In recent years, lightweighting has been a key focus in textile research and development. Composite spinning has led to the development of porous hollow fibers with a hollowness ratio exceeding 40%, while maintaining fiber shape. The strong demand for lightweight fabrics has further spurred the development of porous hollow fibers towards high-hollow-ratio lightweight fabrics. Using water-soluble polymers in alloy composite spinning, the polymer is placed within a core, and then dissolved during processing to form a honeycomb structure of porous hollow fibers. This achieves both lightweighting and increased toughness, but the manufacturing cost of such porous hollow fibers is relatively high.

[0004] Chinese patents CN101748512A, CN103572399A, and CN 105431578A disclose a core-sheath composite fiber and its production method. The sheath polymer is polyester or polyamide, and the core polymer is alkali-soluble copolyester. The cross-section of the sheath is C-shaped, and the core is exposed from one side of the sheath to the outside. After weight reduction, C-shaped fibers are obtained. However, the C-shaped fibers obtained by weight reduction of the aforementioned core-sheath composite fibers do not have a fluffy effect. Summary of the Invention

[0005] The purpose of this invention is to provide a core-sheath composite fiber that, after weight reduction, exhibits good bulkiness, lightweight, and moisture-wicking properties, as well as a profiled fiber obtained by weight reduction of this fiber. The core-sheath composite fiber of this invention can be used in fabrics.

[0006] The technical solution of the present invention is as follows:

[0007] The core-sheath composite fiber has a sheath component made of readily soluble polyester. In the cross-section of the single fiber, the core component is an annular shape with an opening angle of 10° to 60°, preferably 15° to 40°; the contact area between the core component and the sheath component is a wavy line.

[0008] The weight ratio of the core component to the sheath component is preferably 80 / 20 to 40 / 60.

[0009] The ratio of the sheath component distributed within the core component ring to the sheath component distributed outside the core component ring is preferably 80 / 20 to 50 / 50.

[0010] In the cross-section of a single fiber, the core component is preferably circular or polygonal.

[0011] The shaped fiber is obtained by reducing the sheath component of the aforementioned core-sheath composite fiber. The outer surface of the shaped fiber has grooves evenly and continuously distributed along the fiber axis. The groove width is preferably 0.2–4.0 μm, and the groove depth is preferably 0.5–4.0 μm. Preferably, 24–48 grooves are evenly arranged on the outer surface of the shaped fiber.

[0012] In the core-sheath composite fiber of the present invention, the C-shaped core component is completely covered by the sheath component, allowing for production using existing equipment and exhibiting good high-level processability. Furthermore, because the contact area between the core and sheath components on the cross-section of the single fiber of the core-sheath composite fiber has an equal wavy shape, the surface of the resulting profiled fiber after weight reduction has grooves, resulting in better water absorption and water resistance. The core-sheath composite fiber of the present invention can be widely used in fabrics, and the resulting fabrics offer good wearing comfort, making them particularly suitable for sportswear fabrics. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the cross-section of the core-sheath composite fiber of the present invention, where 1 represents the core and 2 represents the sheath.

[0014] Figure 2 This is a photograph of the cross-section of the irregularly shaped fiber after the reduction treatment of the core-sheath composite fiber of the present invention.

[0015] Figure 3 This is a cross-sectional schematic diagram of the core-sheath composite fiber arrangement before the fabric fiber reduction of the present invention.

[0016] Figure 4 This is a cross-sectional schematic diagram of the arrangement of irregular fibers after the fabric fiber reduction of the present invention.

[0017] Figure 5 This is a cross-sectional schematic diagram of the core-sheath composite fiber arrangement before fabric weight reduction in Comparative Example 3, where 3 represents the sheath and 4 represents the core.

[0018] Figure 6This is a cross-sectional schematic diagram of the arrangement of irregular fibers before and after the reduction of fabric weight in Comparative Example 3. Detailed Implementation

[0019] The cross-section of a single fiber of the core-sheath composite fiber of the present invention is as follows: Figure 1 As shown, the core component is a ring with an opening, and the sheath component completely encloses the core component. Fabrics made using this core-sheath composite fiber, after weight reduction, not only have hollow pores within themselves, but also pores formed by the original sheath component exist between each shaped fiber. Therefore, compared to C-type fiber fabrics obtained by conventional methods, the fabrics of this invention have better bulk and lightweight properties. Furthermore, since the core component is not exposed on the outer layer of the sheath component in the core-sheath composite fiber of this invention, its shape is easily controlled and processed.

[0020] The sheath component polymer is an easily soluble polyester, which can be a copolymer of polyethylene terephthalate and polyethylene glycol, or a copolymer with polyethylene terephthalate and polyethylene glycol as the first and second components and isophthalate sulfonate as the third component. From the viewpoint of weight reduction and the fiber opening property of the reduced core fibers, a polyester copolymerized with 3 mol% to 20 mol% sodium isophthalate 5-sulfonate, or a polyester copolymerized with 5 wt% to 15 wt% polyethylene glycol (molecular weight 500 to 3000 g / mol) in addition to the aforementioned sodium isophthalate 5-sulfonate, is preferred. The aforementioned preferred easily soluble polyester can maintain crystallinity and, at the same time, can form a highly oriented fiber structure without hindering the deformation of the core component during the fiber-making process.

[0021] The core component polymer is a thermoplastic polymer, such as polyester, polyamide, polyethylene, polypropylene, polylactic acid, or other melt-molded polymers and their copolymers. Polymers with a melting point of 165°C have good heat resistance and are therefore preferred. Alternatively, modified thermoplastic polymers can be used, for example, by adding inorganic substances such as titanium dioxide, silicon dioxide, and barium oxide, as well as colorants such as carbon black, dyes, and pigments, flame retardants, fluorescent whitening agents, antioxidants, or ultraviolet absorbers.

[0022] In the cross-section of a single fiber of the core-sheath composite fiber of the present invention, the core component is an annular ring with an opening angle of 10° to 60°. When the opening angle is less than 10°, the reduction of the inner sheath component of the core component is insufficient, affecting the lightweight nature of the profiled fiber, or the reduction time is too long, resulting in increased production costs. When the opening angle is greater than 60°, the reduction can easily cause the profiled fibers to collapse and entangle, leading to a decrease in the bulkiness and lightweight nature of the fabric. Preferably, the opening angle of the present invention is 15° to 40°.

[0023] In the core-sheath composite fiber of the present invention, if the core component ratio is too high, it is difficult to form a good opening, and the core component opening is prone to closure; if the core component ratio is too low, it is easy to cause a decrease in the mechanical properties of the fiber and a decline in spinning performance. The preferred weight ratio of the core component to the sheath component in the present invention is 80 / 20 to 40 / 60.

[0024] In the core-sheath composite fiber of the present invention, sheath components are distributed both inside and outside the annular core component. Reducing the amount of sheath components within the annular core component causes the core component to form hollow, irregularly shaped fibers. Reducing the amount of sheath components outside the annular core component further improves the fabric's bulkiness. When fabrics are made using the core-sheath composite fiber of the present invention, the core-sheath composite fibers are tightly arranged. Since adjacent core components in the core-sheath composite fibers have sheath components on their outer layer, the easily soluble sheath components are removed after weight reduction. Therefore, pores exist between the irregularly shaped fibers (the original core components of the core-sheath composite fiber) in the fabric, resulting in better bulkiness.

[0025] When the proportion of the sheath component distributed within the annular core component is too large, it easily leads to poor formation of the outer sheath component of the annular core component, and the gaps between the profiled fibers decrease after weight reduction in the fabric, affecting the fabric's bulkiness. When the proportion of the sheath component distributed within the annular core component is too small, it easily leads to a narrow internal space in the core component, resulting in poor lightweight properties of the profiled fibers after weight reduction. Preferably, the ratio of the sheath component distributed within the annular core component to the sheath component distributed outside the annular core component is 80 / 20 to 50 / 50.

[0026] In the core-sheath composite fiber of the present invention, the core component on the cross-section of a single fiber is preferably circular or polygonal. The polygon can be a triangle, quadrilateral, pentagon, or other polygon with straight sides, or it can be a polygon formed by irregular sides. The core-sheath composite fiber of the present invention refers to a composite fiber bundle containing multiple single fibers. The shape of the core component on the cross-section of each single fiber in a composite fiber bundle can be the same or different. That is, in a composite fiber bundle, there can be a situation where all single fibers have a circular or polygonal core component on their cross-section, or there can be a situation where some single fibers have a circular core component and some single fibers have a polygonal core component. When the core component in the composite fiber bundle used in the fabric is all polygonal or a combination of circular and polygonal, after weight reduction, larger gaps are easily generated between the irregularly shaped fibers in the fabric, which can increase the bulkiness and lightweight of the fabric.

[0027] In the core-sheath composite fiber of the present invention, the contact area between the core component and the sheath component on the cross-section of a single fiber has a wavy shape (e.g., Figure 1 (As shown). The wave lines are distributed in an equal and continuous manner, meaning that the shape, size, and spacing of each wave have no significant deviation.

[0028] After removing the sheath component from the core-sheath composite fiber of the present invention, the resulting shaped fiber has grooves continuously distributed along the fiber axis on its outer surface (e.g., ...). Figure 2 (As shown). The shape of the groove corresponds to the shape of the wavy lines on the composite fiber.

[0029] The grooves are fine, slit-like grooves, providing better waterproofing and absorbency than ordinary fibers. When the groove width and depth are too small, there is no significant advantage after waterproofing and absorbency processing; when the groove width and depth are too large, it easily causes fiber breakage, hollow collapse, and reduces the lightweight and fluffy properties of the fabric. Preferably, the groove width is 0.2–4.0 μm and the depth is 0.5–4.0 μm. The groove arrangement is preferably 24–48 grooves evenly distributed on the outer surface of the fiber. "Evenly distributed" means that the distance between the grooves is approximately the same, not necessarily perfectly uniform. Within this range, the fiber exhibits good waterproofing and absorbency. When the number of surface grooves is too small, the waterproofing and absorbency performance is poor. When the number of surface grooves is too large, it easily causes surface groove breakage, affecting fiber strength.

[0030] The waterproofing and water-absorbing processes are not particularly limited, but it is preferred to use padding, followed by heat treatment at 80-200°C for 1-20 minutes or drying at 80-150°C, and finally shaping and finishing at 130-200°C.

[0031] An example of preparing the processing solution is as follows: First, dilute each component with soft water. Then, add the crosslinking agent, water-repellent agent (or absorbent), and penetrant in sequence. Stir continuously during the preparation process, but the stirring speed should not be too fast to avoid emulsion breakage. The state of the processing solution should be constantly monitored during preparation. Of course, the processing method and solution preparation method should be adjusted locally according to the different textiles to be processed, and different processing agents and their dosages should be selected accordingly.

[0032] The core-sheath composite fiber of the present invention is preferably manufactured by melt spinning, given its productivity and ease of equipment use. However, it is beyond doubt that the core-sheath composite fiber of the present invention can also be manufactured by solvent spinning methods such as solution spinning.

[0033] The spinning temperature in this invention is set below the melting point of the polymer, using the melting point as the standard. This prevents thermal decomposition of the polymer within the spinning head or spinning module, suppressing the reduction in molecular weight and enabling the proper manufacture of the core-sheath composite fiber of this invention.

[0034] In this invention, the polymer discharge rate needs to take into account discharge stability and pressure loss in the discharge orifice. The pressure loss is preferably defined as 0.1 GPa to 40 GPa. Based on the polymer's melt viscosity, discharge orifice diameter, and discharge orifice length, the discharge rate is preferably 0.1 g / min / orifice to 20.0 g / min / orifice per discharge orifice.

[0035] The filaments melted and discharged from the discharge orifice are cooled and solidified, then bundled together by the application of oils or other agents, and drawn by rollers at a predetermined drawing speed. This drawing speed is determined by the discharge volume and the target fiber diameter. In this invention, from the viewpoint of stably manufacturing core-sheath composite fibers, a drawing speed of 100 m / min to 7000 m / min is preferred. From the viewpoint of improving thermal stability and mechanical properties, the resulting core-sheath composite fibers are preferably stretched. This can be done either by stretching the spun core-sheath composite fibers after temporary winding or by stretching them directly without temporary winding.

[0036] The stretching can be performed in a stretching machine consisting of one or more rollers. If the core-sheath composite fiber is made of a thermoplastic polymer that can typically be melt-spun, the fiber axis is prevented from being overstretched and can be heat-set and wound up by setting the temperature of the first roller above the glass transition temperature and below the melting point, and the temperature of the second roller to be equivalent to the crystallization temperature. If the core-sheath composite fiber is made of a polymer that does not exhibit a glass transition, the preheating temperature can be determined by performing a dynamic viscoelasticity (tanδ) measurement of the core-sheath composite fiber and using the temperature above the peak temperature on the high-temperature side of the obtained tanδ. From the viewpoint of improving the stretching ratio and mechanical properties, it is also preferable to perform this stretching process in multiple stages.

[0037] The above describes the manufacturing method of the core-sheath composite fiber of the present invention based on the conventional melt spinning method. It can also be manufactured by melt-blowing and spunbonding methods, and further by solution spinning methods such as wet and dry-wet spinning.

[0038] To produce profiled fibers from the core-sheath composite fiber of the present invention, simply immerse the composite fiber in a solvent in which the easily soluble components can dissolve, and remove the easily soluble sheath components. The solvent can be an alkaline aqueous solution such as sodium hydroxide solution. As a method for treating the composite fiber of the present invention in an alkaline aqueous solution, for example, immersing it in an alkaline aqueous solution after it has been formed into a composite fiber or a fiber structure thereof. In this case, heating the alkaline aqueous solution to 50°C or higher can accelerate hydrolysis, which is therefore preferable. Furthermore, if a fluid dyeing machine or the like is used, large-scale processing can be performed at once, which is preferable from both a production and industrial point of view.

[0039] In the core-sheath composite fiber of the present invention, the core component is covered by the sheath component in each fiber. Therefore, compared with conventional C-shaped core-sheath composite fibers where part of the core component is exposed, the core-sheath composite fiber of the present invention can utilize existing equipment to manufacture high-quality, high-performance fiber materials with high productivity, and the composite fiber exhibits good subsequent high-level processing properties. Simultaneously, using the core-sheath composite fiber of the present invention, it is possible to manufacture C-shaped profiled fibers with fine grooves on both the inner and outer surface. These profiled fibers have smaller openings, making them less prone to entanglement. Furthermore, due to the presence of a certain degree of voids between the fibers in the core-sheath composite fiber...

[0040] The testing method involved in this invention is as follows:

[0041] (1) Fiber strength and elongation

[0042] Stress-deformation curves were measured using the Intex Tensilon tensile testing machine for island-island composite fibers and ultra-fine blended fibers at a sample length of 20 cm and a tensile speed of 100% / min. The load at break was recorded, and this load was divided by the initial fineness to calculate the strength. The deformation at break was recorded, and this was divided by the sample length. The resulting value was multiplied by 100 to calculate the elongation at break. All these values ​​were obtained by repeating the same operation five times using the same standard, and the results were simply averaged. The strength value was rounded to two decimal places, and the elongation was rounded to the nearest decimal place.

[0043] (2) Fluffiness

[0044] The fabric thickness was tested according to standard JIS L 1096 8.4, and the fabric weight and bulk (cm) were tested according to standard JIS L 1096 8.3. 3 / g)=[thickness (mm) / gram weight (g / m)] 2 )]×1000.

[0045] (3) Cross-sectional morphology of core-sheath fibers

[0046] The cross-sectional morphology of the fiber was observed using SEM images.

[0047] (4) Water resistance

[0048] The test and grade determination are carried out according to standard TRS071A-1 method: JISL092.

[0049] (5) Water absorption

[0050] The wicking height was determined according to the standard JIS L 1907:2010 method.

[0051] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. The following embodiments are only for illustrating the technical concept and features of the present invention. It should be noted that for those skilled in the art, improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

[0052] Example 1

[0053] 50% polyester (PET) was used as the core component and 50% easily soluble polyester chips were used as the sheath component. These components were pre-crystallized and dried to a moisture content below 50 ppm, then fed into separate hoppers. At a specific temperature, they entered a core-sheath composite spinning assembly. Through a spinneret design, the core component ring was circular in cross-section, with an opening angle of 25°, and the ratio of the inner to outer sheath layer was 60:40. After cooling, forming, and oiling, the fibers passed through a duct and were then guided by rollers into a winding machine to be wound into POY spools.

[0054] POY yarn is passed through a high-temperature heating box and then false-twisted to obtain core-sheath type DTY yarn with an elongation of about 30%. Through spinneret design and fiber fineness control, the contact area between the core and sheath components is made wavy, and the opening angle on the core component is 25°.

[0055] Using the aforementioned core-sheath DTY composite yarns, a fabric with a thickness of 0.10 mm was prepared. The fabric underwent alkali reduction treatment, resulting in a weight reduction rate of 50%–55% after sheath removal. Following heat treatment and dyeing / setting, the finished fabric was obtained. SEM analysis revealed 36 grooves on the outer surface of the shaped fibers, with a groove width of 1.0 μm and a groove depth of 2.0 μm. The thickness and weight of the reduced-weight fabric were measured, and the bulk was calculated. The finished fabric was then impregnated with Daikin's non-fluorinated waterproofing agent XF5001, a crosslinking agent, and a penetrant, followed by drying (130℃ × 2 min) and heat setting (170℃ × 2 min) to obtain a waterproof fabric. The waterproofness of this fabric was then measured. In addition, the finished fabric was subjected to padding with Rihua Company's NR9000 water-absorbing agent and penetrant, followed by drying (130℃×2min) and heat setting (170℃×2min) to obtain a water-absorbing fabric, and the water absorption of the fabric was measured. Specific parameters are shown in Table 1.

[0056] Examples 2-5

[0057] By changing the spinneret design, the opening angle of the core component was changed to 10° (Example 2), 60° (Example 3), 15° (Example 4) and 40° (Example 5), while other aspects were the same as in Example 1, resulting in core-sheath composite fibers.

[0058] Using the aforementioned core-sheath DTY composite yarn, a fabric with a thickness of 0.10 mm was prepared. After processing under the same conditions as in Example 1, the resulting fabric exhibited a certain degree of fluffiness and lightweight. After waterproofing and absorbent treatments, the fabric demonstrated excellent waterproof and absorbent properties; specific parameters are shown in Table 1.

[0059] Examples 6-9

[0060] The ratio of the core component polyester (PET) and the sheath component easily soluble polyester chips was adjusted to core / sheath = 80 / 20 (Example 6), core / sheath = 40 / 60 (Example 7), core / sheath = 90 / 10 (Example 8), and core / sheath = 30 / 70 (Example 9), while other aspects were the same as in Example 1 to obtain core-sheath composite fibers.

[0061] Using the aforementioned core-sheath DTY composite yarn, a fabric was prepared. The fabric thickness, tested under JIS standards, was 0.10 mm. After processing under the same conditions as in Example 1, the finished fabric exhibited a certain degree of fluffiness and lightweight. After waterproofing and absorbent treatments, the fabric demonstrated excellent waterproof and absorbent properties. Specific parameters are shown in Table 1.

[0062] Examples 10-13

[0063] By changing the spinneret design, the ratio of the sheath component inside the core component ring to the sheath component outside the core component ring was adjusted to 80 / 20 (Example 10), 50 / 50 (Example 11), 90 / 10 (Example 12), and 40 / 60 (Example 13), while other aspects remained the same as in Example 1 to obtain core-sheath composite fibers.

[0064] Using the aforementioned core-sheath DTY composite yarn, a fabric with a thickness of 0.10 mm was prepared. After processing under the same conditions as in Example 1, the finished fabric exhibited a certain degree of fluffiness and lightweight. After waterproofing and absorbent treatments, the fabric demonstrated excellent waterproof and absorbent properties. Specific parameters are shown in Table 1.

[0065] Examples 14-17

[0066] By modifying the spinneret design and controlling fiber fineness, the groove widths on the outer surface of the profiled fibers after weight reduction and sheath removal were 0.2 μm (Example 14), 4.0 μm (Example 15), 0.1 μm (Example 16), and 5.0 μm (Example 17), respectively. The resulting fabric exhibited good bulkiness and lightweight properties. After waterproofing and absorbent treatments, the fabric demonstrated certain water resistance and absorbency. Other aspects were the same as in Example 1.

[0067] Using the aforementioned core-sheath DTY composite yarn, a fabric with a thickness of 0.10 mm was prepared. After processing under the same conditions as in Example 1, the finished fabric exhibited a certain degree of fluffiness and lightweight. After waterproofing and absorbent treatments, the fabric demonstrated good water resistance and absorbency. Specific parameters are shown in Tables 1 and 2.

[0068] Examples 18-21

[0069] By modifying the spinneret design and fiber fineness control, the groove depths on the outer surface of the shaped fibers after sheath component removal were 0.5 μm (Example 18), 4.0 μm (Example 19), 0.3 μm (Example 20), and 5.0 μm (Example 21), respectively. Other parameters were the same as in Example 1.

[0070] Using the aforementioned core-sheath DTY composite yarns, a fabric with a thickness of 0.10 mm was prepared. After processing under the same conditions as in Example 1, the finished fabric exhibited a certain degree of fluffiness and lightweight. After waterproofing and absorbent treatments, the fabric demonstrated a certain degree of water resistance and absorbency. Specific parameters are shown in Table 2.

[0071] Examples 22-23

[0072] The core composition was changed to N6 (Example 22) and PP (Example 23), while other aspects remained the same as in Example 1.

[0073] Using the aforementioned core-sheath DTY composite yarn, a fabric with a thickness of 0.10 mm was prepared. After processing under the same conditions as in Example 1, the finished fabric exhibited a certain degree of fluffiness and lightweight. After waterproofing and absorbent treatments, the fabric demonstrated good waterproof and absorbent properties; specific parameters are shown in Table 2.

[0074] Example 24

[0075] The spinneret design was modified so that, in the cross-section of a single fiber in the fiber bundle, the core component ring-shaped structure exhibits both circular and polygonal shapes (see...). Figure 3 The core-sheath composite fiber was obtained in the same manner as in Example 1.

[0076] Using the aforementioned core-sheath DTY composite yarn, a fabric with a thickness of 0.10 mm was prepared. After processing under the same conditions as in Example 1, the resulting fabric exhibited better fluffiness and lightweight properties. After waterproofing and absorbent treatments, the fabric demonstrated good waterproof and absorbent properties; specific parameters are shown in Table 2.

[0077] Examples 25-26

[0078] The spinneret design was modified so that the number of grooves on the outer surface of the resulting shaped fiber after sheath removal was 22 (Example 25) and 50 (Example 26), while other aspects were the same as in Example 1.

[0079] Using the aforementioned core-sheath DTY composite yarns, a fabric with a thickness of 0.10 mm was prepared. After processing under the same conditions as in Example 1, the finished fabric exhibited a certain degree of fluffiness and lightweight. After waterproofing and absorbent treatments, the fabric demonstrated a certain degree of water resistance and absorbency. Specific parameters are shown in Table 2.

[0080] Comparative Example 1

[0081] The opening angle was changed to 5°, and the rest was the same as in Example 1. Specific parameters are shown in Table 3.

[0082] Because the opening angle is small, it is easy to cause insufficient reduction of the inner sheath component of the core component, or the reduction time required is long, which leads to the island component also being reduced, thus reducing the mechanical properties of the fiber.

[0083] Comparative Example 2

[0084] The opening angle was changed to 70°, and other parameters were the same as in Example 1. See Table 3 for specific parameters.

[0085] Due to the large opening angle, the large opening of the core component is prone to hollow collapse and entanglement of the core components, resulting in poor bulkiness and lightweight.

[0086] Comparative Example 3

[0087] The spinneret design has been changed to a standard C-type spinneret. The spinneret is now a core-sheath spinneret with a 25° angled opening in the sheath component. The sheath component is polyester (PET), and the core component is easily soluble polyester. The fiber cross-section is as follows... Figure 5 As shown in the figure. Other parameters are the same as in Example 1, and specific parameters are shown in Table 3.

[0088] Because a standard C-type spinneret is used, the resulting fabric has poor bulkiness after weight reduction.

[0089]

[0090]

[0091]

Claims

1. Core-sheath composite fiber, wherein the sheath component is easily soluble polyester, characterized by: In the cross-section of a single fiber, the core component is an annular ring with an opening angle of 10° to 60°, and the contact point between the core component and the sheath component is wavy. The core-sheath composite fiber is used in clothing fabrics. After the sheath component is removed from the core-sheath composite fiber, the outer surface of the resulting shaped fiber has grooves continuously distributed along the fiber axis, with a groove width of 0.2 to 4.0 μm and a depth of 0.5 to 4.0 μm.

2. The core-sheath composite fiber according to claim 1, characterized in that: The opening angle is 15° to 40°.

3. The core-sheath composite fiber according to claim 1 or 2, characterized in that: The weight ratio of the core component to the sheath component is 80 / 20 to 40 / 60.

4. The core-sheath composite fiber according to claim 1 or 2, characterized in that: distributed... The ratio of the sheath component within the core component ring to the sheath component distributed outside the core component ring is 80 / 20 to 50 / 50.

5. The core-sheath composite fiber according to claim 1 or 2, characterized in that: In the cross-section of a single fiber, the core component ring is circular or polygonal.

6. The application of the core-sheath composite fiber of claim 1 in fabrics.

7. A shaped fiber, obtained by reducing the amount of sheath component removed from the core-sheath composite fiber of claim 1.

8. The irregularly shaped fiber according to claim 7, characterized in that: The outer surface of the fiber has grooves that are continuously distributed along the fiber axis, the width of which is 0.2 to 4.0 μm and the depth of which is 0.5 to 4.0 μm.

9. The irregularly shaped fiber according to claim 7 or 8, characterized in that: The outer surface of the shaped fiber has 24 to 48 grooves evenly arranged.

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