Biodegradable self-curling bicomponent composite elastic fiber

Abstract

The application discloses a biodegradable self-crimping bicomponent composite elastic fiber, which is prepared from biodegradable polybutylene succinate and polylactic acid as raw materials, with a mass ratio of 20 / 80-80 / 20, through vacuum drying, screw extrusion melting and parallel composite spinning, and through blowing, cooling, oiling, drafting and winding processes. The self-crimping bicomponent composite elastic fiber has good compatibility and biodegradability, can effectively reduce environmental pollution, has good mechanical properties, tensile elasticity and elastic recovery performance, and is suitable for application in the fields of elastic fibers for textiles, medical devices and household supplies.

Description

Technical Field

[0001] This invention relates to an elastic fiber, and more particularly to a biodegradable self-crimping bicomponent composite elastic fiber and its preparation method, belonging to the field of textile materials technology. Background Technology

[0002] Elastic composite fibers, also known as self-crimping fibers, are made by spinning raw materials with different structures or properties in a certain proportion. Their key feature is the utilization of the differences in heat shrinkage properties and initial modulus between the two components of the same fiber, causing the fiber to bend off-axis and exhibit a permanent three-dimensional spiral crimp. This crimp is characterized by its durability, stability, and excellent elasticity, giving fabrics better elasticity and bulkiness. Since no additional texturing treatment is required, it saves energy and avoids mechanical damage to the fibers caused by texturing equipment, making it highly valuable and favored by the fiber manufacturing industry.

[0003] In recent years, with the increase and expansion of market demand for elastic fibers, most of the raw materials for the preparation of elastic fibers currently use traditional polymers that are difficult to degrade, such as polyethylene terephthalate (PET), polypropylene terephthalate (PTT), and polyamide 6 (PA6). For example, the paper "Self-Curling Structure and Properties of PTT / PET Side-by-Side Composite Fibers" [Luo Jin, Donghua University, 2010] obtained self-curling fibers of PTT / PET through melt composite spinning, and analyzed and characterized the crimping characteristics of PTT / PET side-by-side bicomponent fibers, showing that the fibers have good elasticity and durability; Patent CN111118665A discloses a polyester-nylon composite yarn and its preparation method, specifically a PA6 / PET three-dimensional helical structure side-by-side composite fiber. Although it solves the problem of "uneven stripe pattern" in knitted fabrics, it generates polluting waste after use; Patent CN104499091B discloses a polyester side-by-side composite yarn and its preparation method, specifically a high dyeing rate PBT / modified PET side-by-side composite yarn, which has a much higher dyeing rate than ordinary fibers and less floating color after dyeing. The resulting material has broad prospects in the field of clothing fabrics, but still has the potential for non-degradable pollution.

[0004] The waste generated from the use of traditional polymer raw materials in the production of the aforementioned elastic fibers causes white pollution and microplastic pollution to the environment: these wastes remain in fields, affecting crops' absorption of water and nutrients, inhibiting crop growth and development, leading to reduced crop yields, and in severe cases, polluting groundwater; they also remain in nature for a long time, with plastic, paper scraps, and dust flying in the wind, polluting the air and animal habitats; in addition, the tiny plastic particles that remain in the environment for a long time can enter the human body through ingestion and respiration, seriously affecting human health. To solve the above problems, this invention proposes a scheme for preparing self-crimping fibers using biodegradable materials as raw materials. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned problems by providing a biodegradable, self-crimping bicomponent composite elastic fiber, which addresses the issues of white pollution and microplastic pollution caused by the waste generated from polymer raw materials in the production of existing elastic fibers.

[0006] The technical solution of this invention is: a biodegradable, self-crimping bicomponent composite elastic fiber, comprising a component A and a component B with good compatibility. The component A is polybutylene succinate, an aliphatic bio-based biodegradable polyester with excellent comprehensive properties, good crystallinity, and superior fiber-forming performance. Component B is polylactic acid, a bio-based polymer formed from corn, potatoes, beets, or grain starch through fermentation, purification, and a series of reactions. Polylactic acid is environmentally friendly and biodegradable, directly producing carbon dioxide and water after degradation. Furthermore, the production process has low energy consumption, and the resulting fiber products not only have good antibacterial properties but are also skin-friendly and sweat-wicking. The mass ratio of polybutylene succinate to polylactic acid is 20 / 80 to 80 / 20.

[0007] The aforementioned biodegradable self-crimping bicomponent composite elastic fiber is prepared using a side-by-side spinning method, specifically including the following steps:

[0008] Step (1) After vacuum drying, polybutylene succinate chips are melt-pretreated by a screw extruder (the main screw temperature is 215-225℃ and the auxiliary screw temperature is 220-225℃). After precise metering by a metering pump, they are transported to the spinning box and evenly distributed into the parallel composite spinning device in the spinning box.

[0009] Step (II) After the polylactic acid chips are vacuum dried, they are melt-pretreated by a screw extruder (where the temperature of the main screw is 215-225℃ and the temperature of the auxiliary screw is 220-225℃). After being accurately metered by a metering pump, they are transported to the spinning box and evenly distributed into the parallel composite spinning device in the spinning box.

[0010] Step (3) The melts of polybutylene succinate and polylactic acid are simultaneously injected into the spinneret inside the parallel composite spinning device. After composite processing, several fiber monofilaments with parallel structures are extruded. Then, through blowing cooling treatment, oiling treatment, stretching treatment and winding treatment, the uniformity and weavability of the fiber are effectively improved, and a biodegradable self-crimping bicomponent composite elastic fiber is obtained.

[0011] Furthermore, in the above technical solutions: the intrinsic viscosity of the polybutylene succinate is 1.5-1.8 dL / g, and the melting temperature is 185-220℃; the number-average molecular weight of the polylactic acid is 200,000-300,000 g / mol, and the melting temperature is 190-225℃.

[0012] Furthermore, in the above-mentioned method for preparing biodegradable self-crimping bicomponent composite elastic fibers, the spinning temperature of the composite spinning device is 190–225°C.

[0013] Furthermore, in the above-mentioned method for preparing biodegradable self-crimping bicomponent composite elastic fibers, the air-blowing cooling treatment adopts a side-blowing method, the air-blowing cooling air temperature is 10-15℃, and the air-blowing cooling air pressure is 100-200Pa.

[0014] Specifically, the side-blowing method can be divided into two stages: the first stage has a cooling air temperature of 12.5 to 15°C, and the second stage has a cooling air temperature of 10 to 12.5°C.

[0015] Furthermore, in the above-mentioned method for preparing biodegradable self-crimping bicomponent composite elastic fibers, the stretching process employs two or more pairs of stretching rollers, with a stretching ratio of 1.5 to 2.5, and a stretching heat setting temperature of 70 to 95°C.

[0016] Furthermore, in the above-mentioned method for preparing biodegradable self-crimping bicomponent composite elastic fibers, the winding speed used in the winding process is 2500–3200 m / min.

[0017] Furthermore, in the above-mentioned method for preparing biodegradable self-crimping bicomponent composite elastic fibers, several of the fiber monofilaments are placed freely and are all bent in an "S" shape with a fluffy and swollen portion.

[0018] Furthermore, in the above-mentioned method for preparing biodegradable self-crimping bicomponent composite elastic fibers, the composite spinning linear density between several fiber monofilaments is 100-200 dtex.

[0019] Thus, by adopting the technical solution of the present invention, the biodegradable self-crimping bicomponent composite elastic fiber is finally obtained, in which the two components are arranged in parallel, one component being polybutylene succinate and the other component being polylactic acid.

[0020] Compared with existing technologies, the technical solution of this invention uses biodegradable raw materials, exhibiting good compatibility and biodegradability. This effectively reduces environmental pollution and avoids soil and water pollution and ecological damage caused by long-term retention of waste in the natural environment, thus possessing good application prospects and market value. Moreover, no phase separation phenomenon is observed in its cross-section, demonstrating high chemical stability. The breaking strength can reach 2.4–3.0 cN / dtex, the breaking elongation can reach 20–60%, and the elastic recovery rate can reach 70–90%. It possesses excellent mechanical properties, tensile elasticity, and elastic recovery properties, making it suitable for applications in elastic fibers such as textiles, medical devices, and household goods.

[0021] In addition, the preparation method of this biodegradable self-crimping bicomponent composite elastic fiber is simple, practical and easy to operate. It can be spun using a composite spinning device to achieve industrial mass production and has a wide range of applications. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is further described below with reference to specific examples. However, it should not be construed that the scope of protection of the above-mentioned subject matter of this invention is limited to the following embodiments. All raw materials used are commercially available or prepared using methods known in the industry.

[0023] Example 1

[0024] Polybutylene succinate (PPS) is used as component A, and polylactic acid (PLA) is used as component B. The two are combined by screw extrusion melt spinning in parallel.

[0025] Step (1) Polybutylene succinate chips with an intrinsic viscosity of 1.53 dL / g are vacuum dried at 70℃ for 24 hours, then heated and melted by a main screw at a temperature of 215℃. After being accurately metered by a metering pump, the chips are transported to the spinning box and evenly distributed into the parallel composite spinning device.

[0026] Step (II) Polylactic acid chips with a number average molecular weight of 250,000 g / mol are vacuum dried at 70°C for 24 hours, then heated and melted by a secondary screw at a temperature of 222°C. After being accurately metered by a metering pump, the chips are transported to the spinning box and evenly distributed into the parallel composite spinning device within the spinning box.

[0027] Step (3) The melts of polybutylene succinate and polylactic acid are simultaneously injected into the spinneret inside the parallel composite spinning device. The temperature of the composite spinning device is 222℃. After composite spinning, several fiber monofilaments with parallel structures are extruded. They are then cooled by side blowing and spinning tunnel, with the blowing cooling temperature at 11.5℃ and the blowing cooling air pressure at 100Pa. They are then sequentially bundled and oiled, drawn with a draw ratio of 2.0, and wound on a winding machine at a speed of 3000m / min to obtain biodegradable self-crimping bicomponent composite elastic fiber.

[0028] Example 2

[0029] Polybutylene succinate (PPS) is used as component A, and polylactic acid (PLA) is used as component B. The two are combined by screw extrusion melt spinning in parallel.

[0030] Step (1) Polybutylene succinate chips with an intrinsic viscosity of 1.53 dL / g are vacuum dried at 70℃ for 24 hours, then heated and melted by a main screw at a temperature of 215℃. After being accurately metered by a metering pump, the chips are transported to the spinning box and evenly distributed into the parallel composite spinning device.

[0031] Step (II) Polylactic acid chips with a number average molecular weight of 250,000 g / mol are vacuum dried at 70°C for 24 hours, then heated and melted by a secondary screw at a temperature of 222°C. After being accurately metered by a metering pump, the chips are transported to the spinning box and evenly distributed into the parallel composite spinning device within the spinning box.

[0032] Step (3) The melts of polybutylene succinate and polylactic acid are simultaneously injected into the spinneret inside the parallel composite spinning device. The temperature of the composite spinning device is 222℃. After composite spinning, several fiber monofilaments with parallel structures are extruded. They are then cooled by side blowing and spinning tunnel, with the blowing cooling temperature at 11.5℃ and the blowing cooling air pressure at 100Pa. They are then sequentially bundled and oiled, drawn with a draw ratio of 2.0, and wound on a winding machine at a speed of 3000m / min to obtain biodegradable self-crimping bicomponent composite elastic fiber.

[0033] Example 3

[0034] Polybutylene succinate (PPS) is used as component A, and polylactic acid (PLA) is used as component B. The two are combined by screw extrusion melt spinning in parallel.

[0035] Step (1) Polybutylene succinate chips with an intrinsic viscosity of 1.86 dL / gdL / g are vacuum dried at 70℃ for 24 hours, then heated and melted by a main screw at a temperature of 225℃. After being accurately metered by a metering pump, the chips are transported to the spinning box and evenly distributed into the parallel composite spinning device within the spinning box.

[0036] Step (3) Polylactic acid chips with a number average molecular weight of 250,000 g / mol are vacuum dried at 70°C for 24 hours, then heated and melted by a secondary screw at a temperature of 222°C. After being accurately metered by a metering pump, the chips are transported to the spinning box and evenly distributed into the parallel composite spinning device.

[0037] Step (3): The melts of polybutylene succinate and polylactic acid are simultaneously injected into the spinneret inside the parallel composite spinning device. The temperature of the composite spinning device is 225℃. After composite spinning, several fiber monofilaments with parallel structures are extruded. They are then cooled by side blowing and spinning tunnel, with the blowing cooling temperature at 11.5℃ and the blowing cooling air pressure at 100Pa. They are then sequentially bundled and oiled, drawn with a draw ratio of 2.5, and wound on a winding machine at a speed of 3000m / min to obtain biodegradable self-crimping bicomponent composite elastic fiber.

[0038] Example 4

[0039] Polybutylene succinate (PPS) is used as component A, and polylactic acid (PLA) is used as component B. The two are combined by screw extrusion melt spinning in parallel.

[0040] Step (1) Polybutylene succinate chips with an intrinsic viscosity of 1.86 dL / gdL / g are vacuum dried at 70℃ for 24 hours, then heated and melted by a main screw at a temperature of 225℃. After being accurately metered by a metering pump, the chips are transported to the spinning box and evenly distributed into the parallel composite spinning device within the spinning box.

[0041] Step (II) Polylactic acid chips with a number average molecular weight of 250,000 g / mol are vacuum dried at 70°C for 24 hours, then heated and melted by a secondary screw at a temperature of 222°C. After being accurately metered by a metering pump, the chips are transported to the spinning box and evenly distributed into the parallel composite spinning device within the spinning box.

[0042] Step (3): The melts of polybutylene succinate and polylactic acid are simultaneously injected into the spinneret inside the parallel composite spinning device. The temperature of the composite spinning device is 225℃. After composite spinning, several fiber monofilaments with parallel structures are extruded. They are then cooled by side blowing and spinning tunnel, with the blowing cooling temperature at 11.5℃ and the blowing cooling air pressure at 100Pa. They are then sequentially bundled and oiled, drawn with a draw ratio of 2.5, and wound on a winding machine at a speed of 3000m / min to obtain biodegradable self-crimping bicomponent composite elastic fiber.

[0043] Comparative Example 1

[0044] Polyethylene terephthalate (PET) and polypropylene terephthalate (PTT) were melt-spun together in a 50:50 mass ratio to obtain PET / PTT composite elastic fibers.

[0045] Performance testing and result comparison —

[0046] 1. The mechanical properties of the composite elastic fibers obtained in Examples 1-4 and Comparative Example 1 were tested. The specific testing methods are as follows.

[0047] Viscosity property testing: The intrinsic viscosity of the polymer was determined using an Ubbelohde viscometer at 25 ± 0.01 °C, using a mixed solvent of phenol and 1,1,2,2-tetrachloroethane (1:1 w / w) at a polymer concentration of 0.50 g·dL. -1 .

[0048] Number-average molecular weight determination: The molecular weight of polyester was determined using ultra-high performance polymer chromatography (APC, Waters). The mobile phase used was hexafluoroisopropanol, and the flow rate was 0.3 mL / min. -1 .

[0049] Breaking strength and elongation at break were tested using a YG020B electronic single yarn tensile testing machine. The fiber holding length was 200 mm, the stretching rate was 200 mm / min, and the pre-tension was 5 cN. Each group of samples was tested 15 times, and the average value was taken to obtain the fiber's breaking strength and elongation at break.

[0050] Elastic recovery rate testing: The YG026Q fabric tensile testing machine was used for testing. A relatively uniform portion of the composite fiber (randomly cut length) was selected to test the elastic recovery rate of the sample after 30 stretches with a fixed elongation of 20%. The fiber holding length was 250 mm, and the stretching rate was 50 mm / min.

[0051] The formula for calculating the elastic recovery rate is as follows:

[0052]

[0053] Specifically, L0 is the spacing length, L1 is the length when the sample returns to the zero position and is held for 60 seconds before applying pretension, L2 is the length when the sample is stretched to a certain elongation, L is the elongation when the sample is loosely clamped and reaches pretension, and L is 0 when the sample is clamped under pretension.

[0054] The specific test results and test standards are shown in Table 1.

[0055] Table 1: Mechanical property test data of Examples 1-4 and Comparative Example 1

[0056]

[0057] As shown in Table 1: Compared with Comparative Example 1, the fracture strength data of Examples 1-4 clearly show that Examples 1-4 have better strength; compared with Comparative Example 1, the elastic recovery rate data of Examples 3-4 clearly show that Examples 2-4 have better elasticity. In summary, the embodiments of the present invention have good mechanical strength, tensile elasticity, and elastic recovery.

[0058] 2. The biodegradation rate of Examples 1-4 and Comparative Example 1 was tested. The test method was in accordance with GB / T 32366-2015, and the specific test standards and test results are shown in Table 2.

[0059] Table 2: Biodegradation rate detection data of Examples 1-4 and Comparative Example 1

[0060]

[0061] As shown in Table 2: Compared with Comparative Example 1, Examples 1 to 4 of the present invention have better compatibility and biodegradability, thus effectively protecting the environment.

[0062] In this invention, the raw materials used are fully biodegradable and environmentally friendly: polybutylene succinate and polylactic acid. This is the key technology of this invention, as their elastic moduli differ significantly, making them ideal raw materials for bio-based self-crimping elastic fibers. The bicomponent composite elastic fibers are then processed through a parallel spinning process, resulting in fibers with good tensile deformation resistance and low elastic recovery fatigue. For the composite spinning device and related equipment or components, those skilled in the art can perform conventional setups based on existing technology; this invention does not have special requirements regarding model selection or combination.

[0063] As can be seen from the above description, compared with the prior art, the technical solution of this invention uses biodegradable raw materials, exhibiting good compatibility and biodegradability. This effectively reduces environmental pollution and avoids soil and water pollution and ecological damage caused by long-term retention of waste in the natural environment, demonstrating promising application prospects and market value. Furthermore, its cross-section does not exhibit phase separation, possessing high chemical stability. Its breaking strength can reach 2.4–3.0 cN / dtex, breaking elongation can reach 20–60%, and elastic recovery rate can reach 70–90%, exhibiting excellent mechanical properties, tensile elasticity, and elastic recovery performance. It is suitable for applications in elastic fibers such as textiles, medical devices, and household goods. In addition, the preparation method of this biodegradable self-crimping bicomponent composite elastic fiber is simple, practical, and easy to operate. It can be spun using a composite spinning device for industrial mass production, resulting in a wide range of applications.

[0064] The technical solution, working process, and implementation effects of the present invention have been described in detail above. It should be noted that the described examples are only typical examples of the present invention. In addition, the present invention may have many other specific implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed by the present invention.

Claims

1. A biodegradable, self-crimping bicomponent composite elastic fiber, comprising component A and component B with good compatibility, characterized in that: The mass ratio of component A to component B is 20 / 80 to 80 / 20; component A is polybutylene succinate, with an intrinsic viscosity of 1.5 to 1.8 dL / g and a melting temperature of 185 to 220°C; component B is polylactic acid, with a number-average molecular weight of 200,000 to 300,000 g / mol and a melting temperature of 190 to 225°C; the composite elastic fiber has a breaking strength of 2.4 to 3.0 cN / dtex, a breaking elongation of 20 to 60%, and an elastic recovery rate of 70 to 90%, and is prepared by parallel spinning through the following steps: Step S1: Vacuum dry the slices of component A and component B, extrude them into melt through a screw extruder, accurately meter them through a metering pump and transport them into the spinning box, and then evenly distribute them into the parallel composite spinning device; Step S2: The melts of polybutylene succinate and polylactic acid are simultaneously injected into the spinneret inside the parallel composite spinning device. After composite processing, several fiber monofilaments with a parallel structure are extruded. Then, the fibers undergo air cooling, oiling, stretching, and winding processes. The stretching process uses two or more pairs of stretching rollers with a stretching ratio of 1.5 to 2.5 and a stretching heat setting temperature of 70 to 95°C. The winding process uses a winding speed of 2500 to 3200 m / min to obtain biodegradable self-crimping bicomponent composite elastic fibers.

2. The biodegradable self-crimping bicomponent composite elastic fiber according to claim 1, characterized in that: In step S2, the spinning temperature of the composite spinning device is 190–225°C.

3. The biodegradable self-crimping bicomponent composite elastic fiber according to claim 1, characterized in that: In step S2, the air cooling process adopts a side-blowing method, with the air cooling temperature being 10-15℃ and the air cooling pressure being 100-200Pa.

4. The biodegradable self-crimping bicomponent composite elastic fiber according to claim 1, characterized in that: In step S2, when the several fiber monofilaments are placed freely, they are all bent in an "S" shape and have a fluffy, swollen part.

5. The biodegradable self-crimping bicomponent composite elastic fiber according to claim 1, characterized in that: In step S2, the composite spinning linear density between several fiber monofilaments is 100-200 dtex.

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