Durable resilient high-poly lactic acid filling material and preparation method thereof

Abstract

The application discloses a kind of durable resilience high poly lactic acid filling material and preparation method thereof, belong to textile field.Aiming at the problems of existing poly lactic acid in fiber preparation, such as easy broken wire and poor mechanical properties, the application provides a kind of durable resilience high poly lactic acid filling material, including main base material and auxiliary material: the main base material is poly lactic acid;Auxiliary material includes polyurethane elastomer, modified filler, antioxidant, nucleating agent and branching agent;Among them, the weight ratio of polyurethane elastomer in auxiliary material and main base material is (0.06~0.3):1;The weight ratio of modified filler in auxiliary material and main base material is (0.2~0.6):1.The application acts on poly lactic acid by polyurethane elastomer and modified filler, finally improves the resilience of poly lactic acid material, so that the prepared fiber is soft and fluffy, significantly reduces the frequency of spinning broken wire, ensures the resilience and fluffiness of fiber, improves its performance as home textile filling material, improves satisfaction, promotes the development of environment-friendly degradable material market.

Description

Technical Field

[0001] This invention belongs to the field of textile technology, and more specifically, relates to a durable and resilient polylactic acid filler material and its preparation method. Background Technology

[0002] Three-dimensional hollow fiber technology is a key technology specifically designed for preparing fibers with three-dimensional crimped structures and hollow cross-sections. Fibers produced using this technology possess core properties such as low linear density, high bulkiness, excellent warmth retention, and good breathability, demonstrating wide application value in home textiles, apparel, and other fields. In terms of manufacturing processes, direct melt spinning is currently the mainstream technology. This method, due to its mature technology and economic advantages, has become the preferred production method for most domestic enterprises. Its core principle is to construct the hollow structure through a specially designed hollow spinneret: microporous conduits are integrated inside the spinneret, and nitrogen or air is precisely injected into the fiber cavity through these conduits, thereby stabilizing and forming a hollow cross-section structure, laying the foundation for the fiber's low linear density and high bulkiness. Polylactic acid (PLA) as the matrix material endows three-dimensional hollow fibers with unique performance advantages. PLA is a biodegradable polymer that can be completely degraded into carbon dioxide and water through microbial action in the natural environment, exhibiting excellent biocompatibility and sustainability. Meanwhile, the low density of PLA itself, combined with its hollow structure, creates a synergistic effect, further reducing fiber linear density and improving the lightweight and comfort of the products. Its three-dimensional crimped configuration creates numerous porous structures between the fibers, significantly enhancing the material's bulkiness and elastic recovery properties. However, the production of polylactic acid-based three-dimensional hollow fibers still faces multiple technical challenges: Firstly, degradation during the spinning process is a significant issue: PLA molecules are rich in ester bonds, making them susceptible to thermo-oxidative degradation and shear-induced degradation under the high-temperature environment (typically 180-220℃) and strong shearing conditions of spinning. This leads to a significant decrease in molecular weight and fluctuations in melt viscosity, consequently impairing spinning stability. Specifically, this manifests as frequent fiber breakage and fuzzing, and significant fluctuations in the fiber's tensile strength, elongation at break, and other mechanical properties. While this can be mitigated by adding antioxidants and heat stabilizers, these additives may increase production costs or negatively impact the fiber's biodegradability. Secondly, structural control is challenging: the "hollowness" and "three-dimensional crimp morphology" of three-dimensional hollow fibers are key indicators determining their bulkiness, warmth retention, and resilience. Due to the significant differences in melt flow and crystallization behavior between PLA and traditional synthetic fibers (such as polyester and nylon), the hollow structure is prone to morphological defects such as collapse and eccentricity during the molding process, directly affecting the fiber's bulkiness and warmth retention. At the same time, the stability of the three-dimensional crimping effect is insufficient. During high-temperature processing, the thermal shrinkage characteristics of PLA easily cause the crimped structure to loosen, leading to a decrease in fiber resilience. Thirdly, its mechanical properties have shortcomings: PLA is a typical brittle polymer material. When the fibers have a high degree of crystallinity after post-treatment and shaping, its elongation at break is low and its impact resistance is insufficient. Under repeated stress (such as rubbing and stretching), it is prone to embrittlement and fracture, which shortens the service life of filling cotton, fabrics, and other products. Especially in the field of clothing filling, after long-term washing or compression, the fibers are prone to breakage and clumping, which seriously affects the material's fluffiness retention.

[0003] Corresponding improvements have been made to address the aforementioned issues. For example, Chinese Patent Application No. CN201811637505.3, published on June 7, 2019, discloses a polylactic acid / polyester elastomer composite elastic fiber. This composite elastic fiber is prepared by composite spinning of polylactic acid chips, polyester elastomer chips, and a compatibilizer in a mass ratio of 30–70: 70–30: 0–10. This invention also provides a method for preparing the aforementioned elastic fiber. The shortcomings of this patent are: although the elasticity of the material is improved to some extent by using polyester elastomer and compatibilizer, the improvement of elasticity by a single component is limited, and the large amount of polyester elastomer added reduces the material strength and durability. Summary of the Invention

[0004] 1. The problem to be solved To address the problems of easy fiber breakage and poor mechanical properties in existing polylactic acid (PLA) fiber manufacturing, this invention provides a durable, resilient, high-resilience PLA filling material and its preparation method. By combining polyurethane elastomers and modified fillers to act on PLA, the inherent brittleness of PLA is effectively improved, solving the problem of easy fiber breakage during PLA spinning. Chemical blending modification addresses morphological defects such as collapse and eccentricity that easily occur during PLA hollow fiber molding, ensuring the fiber's resilience and bulkiness. This enhances its performance as a filling material for pillows, quilts, and other home textiles, increasing customer satisfaction and promoting the development of the environmentally friendly and biodegradable materials market.

[0005] 2. Technical Solution To solve the above problems, the present invention adopts the following technical solution.

[0006] A durable, resilient polylactic acid filler material, comprising a main base material and auxiliary materials: The main base material is polylactic acid; the auxiliary materials include polyurethane elastomer, modified filler, antioxidant, nucleating agent and branching agent; wherein, the weight ratio of polyurethane elastomer to main base material in the auxiliary materials is (0.06~0.3):1; the weight ratio of modified filler to main base material in the auxiliary materials is (0.2~0.6):1; the molecular weight of polylactic acid in the main base material is 100,000~150,000.

[0007] Furthermore, it includes the following components in parts by weight: 50-75 parts polylactic acid; 15-30 parts modified filler; 5-15 parts polyurethane elastomer; 0.3-0.7 parts antioxidant; 1.3-4 parts nucleating agent; and 0.3-3 parts branching agent.

[0008] Furthermore, the modified filler is polybutylene adipate terephthalate; the polyurethane elastomer is one or two of waterborne polyurethane resin, thermoplastic polyurethane elastomer, or cast polyurethane elastomer.

[0009] Furthermore, the antioxidant is one or two of antioxidant 168 and antioxidant 1010; the nucleating agent is one or two of starch, cellulose nanocrystals, chitosan, and dibenzylidene sorbitol; and the branching agent is one or two of citric acid, glycerol, epoxidized soybean oil, and hexamethylene diisocyanate.

[0010] A method for preparing a durable, resilient polylactic acid filler material as described in any of the above technical solutions includes the following steps: Raw material mixing: The main base material and auxiliary materials are mixed evenly to obtain a mixture; Slices: The mixture is extruded and pelletized at 165~190℃ using a twin-screw extruder to obtain modified polylactic acid chips; Drying and pre-crystallization: Modified polylactic acid chips are placed in a drying tower for drying; Preparation of primary growth filaments with hollow structures: The dried modified polylactic acid chips were sequentially subjected to heating and melting, precise extrusion, and rapid cooling to obtain primary growth filaments with hollow structures; Bundling and drawing: Multiple nascent filaments are bundled together by a guide and fed into a drawing machine. They are then drawn at 70-120°C with a drawing ratio of 2-5 times and heat-set. Curling and cutting: The shaped filaments are fed into a crimping machine and mechanically extruded to form wavy crimps; finally, they are cut by a cutting machine to obtain polylactic acid hollow fibers.

[0011] Furthermore, during the drying and pre-crystallization process, the drying parameters are as follows: drying at 80~100℃ and vacuum degree -0.08~-0.09MPa for 4~8 hours to control the moisture content below 70ppm.

[0012] Furthermore, the specific steps for preparing the initial growth filament with a hollow structure include: feeding the dried particles into a barrel, melting them in a twin-screw extruder at 160~200℃, extruding them from the extrusion die at 170~210℃, filtering them through a filter device, and then metering and conveying the melt to a spinning assembly with a hollow spinneret at 185~220℃. After being extruded through the spinneret orifice, the melt is rapidly cooled and solidified by side blowing or ring blowing to form the initial growth filament with a hollow structure.

[0013] Furthermore, the obtained polylactic acid hollow fiber has a tensile strength of 3.7~5.2 cN / dtex and an elongation elastic recovery rate of 80~95%.

[0014] 3. Beneficial effects (1) This invention adds polyurethane elastomer to polylactic acid (PLA). By inserting the soft segments of the polyurethane elastomer into the PLA molecular chain, hydrogen bonds are weakened, resulting in a lower Tg, improved chain segment mobility, and improved material processability. The hard segments of the polyurethane elastomer form hydrogen bonds with the PLA ester bonds, enhancing interfacial compatibility. Energy is absorbed through entropic elastic deformation, resulting in improved resilience and reduced plastic deformation. Modified fillers are added, and through interaction between the modified fillers and PLA, a flexible network is built to dissipate stress, which can improve its elongation at break and reduce crystallinity, thus optimizing melt flowability. Through the combined action of polyurethane elastomer and modified filler, the resilience of the PLA material is ultimately improved, making the prepared fibers soft and fluffy, and significantly reducing the frequency of spinning breakage. The amount of polyurethane elastomer used is also limited. The addition amount is moderate, which does not affect the biodegradability of polylactic acid itself. Furthermore, the synergistic effect of the modified filler and nucleating agent does not lead to a decrease in material strength, thus affecting material durability. The amount of modified filler is limited to ensure that its addition is moderate, fully utilizing its toughening, elasticity-enhancing, and processing-improving effects without causing a decrease in strength or processing difficulties. The overall durable and resilient high-resilience polylactic acid filler effectively improves the inherent brittleness of polylactic acid, solves the problem of easy fiber breakage during polylactic acid spinning, and addresses the morphological defects such as collapse and eccentricity that easily occur during the molding of polylactic acid hollow fibers. This ensures the fiber's resilience and fluffiness, improves its performance as a filling material for pillows, quilts, and other home textiles, increases customer satisfaction, and promotes the development of the environmentally friendly and biodegradable materials market. (2) In this invention, polybutylene adipate terephthalate is selected as a modified filler. Because it is soft and has a very high elongation at break, it can effectively transform PLA from a brittle material into a tough material, greatly improving the elongation at break and impact resistance of the composite material. Moreover, the flexible long chain of PBAT can entangle and interact with the PLA molecular chain. When subjected to force, it can effectively dissipate energy through its own plastic deformation and prevent crack propagation. One or two of waterborne polyurethane resin, thermoplastic polyurethane elastomer or cast polyurethane elastomer are selected as polyurethane elastomers. The range of options is wide and the process selection is flexible. Whether it is melt blending or other processes, a suitable type can be found to exert its entropic elasticity and enhance the interfacial bonding through hydrogen bonding. (3) The preparation method of the present invention avoids the hydrolytic degradation of PLA in subsequent high-temperature processing by drying deep dehumidification; by designing the temperature gradient from the barrel to the spinneret, the stable plasticization and full homogenization of the mixing system are ensured, and finally the fiber is extruded from the hollow spinneret with the best melt viscosity and elasticity; the metering pump ensures that the wall thickness and diameter of each hollow fiber are extremely uniform, which is the basis for obtaining consistent mechanical properties and resilience; rapid cooling (side / ring blowing) forms an amorphous structure with a certain degree of orientation that is conducive to subsequent stretching, and finally the polylactic acid hollow fiber has a fiber breaking strength of 3.7~5.2cN / dtex; the constant elongation elastic recovery rate is 80~95%, which takes into account both excellent long-lasting bulkiness and good mechanical properties, making it have broad application prospects. Detailed Implementation

[0015] The present invention will be further described below with reference to specific embodiments.

[0016] A durable, resilient polylactic acid filler material, comprising a main base material and auxiliary materials: The main base material is polylactic acid; the auxiliary materials include polyurethane elastomer, modified filler, antioxidant, nucleating agent and branching agent; wherein, the weight ratio of polyurethane elastomer to main base material in the auxiliary materials is (0.06~0.3):1; the weight ratio of modified filler to main base material in the auxiliary materials is (0.2~0.6):1; the molecular weight of polylactic acid in the main base material is 100,000~150,000.

[0017] In this embodiment, due to the high molecular weight and narrow molecular weight distribution of polylactic acid (PLA) as the main matrix material, the material exhibits high brittleness and poor elasticity, resulting in shortcomings in its mechanical properties as a fiber. Therefore, this application adds auxiliary materials to the main matrix material.

[0018] Antioxidants inhibit thermo-oxidative degradation in the excipients; nucleating agents increase the crystallization rate and reduce crystallinity, thereby improving dimensional stability; branching agents regulate the molecular chain topology, improve interfacial compatibility, and optimize the condensed structure. The branched structure increases the elastic component of the melt, improves the melt strength, and enhances the overall toughness of the material through the branched network, while avoiding the strength loss caused by simple toughening. By inserting soft segments of polyurethane elastomer into PLA molecular chains to weaken hydrogen bonds, the thermal conductivity (Tg) is lowered, chain mobility is improved, and material processability is enhanced. Hydrogen bonds are formed between hard segments of polyurethane elastomer and PLA ester bonds to strengthen interfacial compatibility. Entropy-elastic deformation absorbs energy, resulting in improved resilience and reduced plastic deformation. The interaction between modified fillers and PLA creates a flexible network to dissipate stress, increasing elongation at break while reducing crystallinity and optimizing melt flowability. The combined effect of polyurethane elastomer and modified fillers ultimately improves the resilience of polylactic acid materials, resulting in soft, fluffy fibers and a significant reduction in spinning breakage frequency.

[0019] It is worth noting that high crystallinity results in good strength but is not conducive to processing and the material is prone to curling. Low crystallinity leads to poor strength. In addition to the above effects, polyurethane elastomers can act as heterogeneous nucleating agents to refine spherulites to the submicron level and inhibit crystallization, increase the proportion of amorphous regions, and work synergistically with nucleating agents to regulate the crystallinity of the material. This improves the spherulite size without increasing the crystallinity. Smaller spherulite size increases strength, thus preserving the material strength without causing excessive crystallinity that would affect processing.

[0020] Since polylactic acid (PLA) is a biodegradable material, adding too little polyurethane elastomer (PU) has little effect on improving elasticity, while adding too much can reduce material strength and affect the biodegradability of PLA. Therefore, the content of PU elastomer is limited to ensure that its addition is moderate enough not to affect the biodegradability of PLA and to work synergistically with modified fillers and nucleating agents without reducing material strength or affecting durability. Furthermore, PU elastomer and modified filler work in tandem, so the content of modified filler is also limited. If there is too little modified filler, the PLA matrix may be too brittle and prone to breakage when the PLA elastomer improves resilience. If there is too much modified filler, the flexible network dominates, but this may excessively suppress the elastic response of the PLA elastomer, resulting in a slow rebound and significant strength loss. Therefore, by limiting the amount of PU elastomer and modified filler, it is possible to improve elongation at break and resilience without sacrificing the overall strength and durability of the material.

[0021] Therefore, in summary, when preparing fibers using polylactic acid as a base material, traditional plasticizing methods generally reduce strength. However, in this application, polyurethane elastomer is used as the elastomer phase, rather than a small molecule plasticizer. By modifying the filler, polylactic acid is transformed from a brittle material into a tough material. The high molecular weight polylactic acid continues to provide a robust, load-bearing continuous phase skeleton, ensuring the basic strength and durability of the material. Furthermore, it achieves the soft touch, fluffy shape, and durable resilience of high-quality elastic fibers, thus truly possessing the core competitiveness as a high-end filler material.

[0022] In one specific embodiment, the components include the following parts by weight: 50-75 parts of polylactic acid; 15-30 parts of modified filler; 5-15 parts of polyurethane elastomer; 0.3-0.7 parts of antioxidant; 1.3-4 parts of nucleating agent; and 0.3-3 parts of branching agent.

[0023] In one specific embodiment, the modified filler is polybutylene adipate terephthalate; the polyurethane elastomer is one or two of waterborne polyurethane resin, thermoplastic polyurethane elastomer, or cast polyurethane elastomer.

[0024] Specifically, polybutylene adipate terephthalate (PBAT) has aliphatic soft segments in its molecular chain that interact with PLA to form a flexible network that dissipates stress, thereby improving its elongation at break and reducing crystallinity, thus optimizing melt flowability. At the same time, PBAT and PLA are both aliphatic polyesters with similar chemical structures and good biodegradability. Waterborne polyurethane resin is an environmentally friendly solvent that facilitates uniform dispersion; thermoplastic polyurethane elastomer (TPU) itself has excellent elasticity and abrasion resistance, and can be directly blended and extruded with PLA in the molten state, with strong process compatibility; cast polyurethane elastomer (CPU) is adapted to specific processes; these three options have a wide range and flexible process selection. Whether it is melt blending or other processes, a suitable type can be found to give full play to its entropic elasticity and the role of enhancing interfacial bonding through hydrogen bonding.

[0025] In one specific embodiment, the antioxidant is one or two of antioxidant 168 and antioxidant 1010; the nucleating agent is one or two of starch, cellulose nanocrystals, chitosan, and dibenzylidene sorbitol; and the branching agent is one or two of citric acid, glycerol, epoxidized soybean oil, and hexamethylene diisocyanate.

[0026] Preferably, in this embodiment, a composite antioxidant is used, which includes antioxidant 168 (phosphite antioxidant) and antioxidant 1010 (hindered phenolic antioxidant). The two antioxidants are compounded according to the required ratio. There is a synergistic effect between the phenolic antioxidant and the phosphite. The phosphite antioxidant mainly works during the processing, while the hindered phenolic antioxidant works during the later storage process. The effect is better when both antioxidants are used together.

[0027] A method for preparing a durable, resilient polylactic acid filler material as described in any of the above embodiments includes the following steps: Raw material mixing: The main base material and auxiliary materials are mixed evenly to obtain a mixture; Slices: The mixture is extruded and pelletized at 165~190℃ using a twin-screw extruder to obtain modified polylactic acid chips; Drying and pre-crystallization: Modified polylactic acid chips are put into a drying tower for drying; during the drying and pre-crystallization process, the drying parameters are 80~100℃ and vacuum degree -0.08~-0.09MPa for 4~8 hours to control the moisture content below 70ppm; Preparation of hollow-structured nascent filaments: Dried modified polylactic acid chips are sequentially heated and melted, precisely extruded, and rapidly cooled to obtain nascent filaments with hollow structures. The specific steps for preparing nascent filaments with hollow structures include: feeding dried particles into a barrel, melting them in a twin-screw extruder at 160~200℃, extruding them from the extrusion die at 170~210℃, filtering them, and then metering and conveying the melt to a spinning assembly with a hollow spinneret at 185~220℃. After extrusion through the spinneret orifice, the melt is rapidly cooled and solidified by side blowing or ring blowing to form nascent filaments with hollow structures. Bundling and drawing: Multiple nascent filaments are bundled together by a guide and fed into a drawing machine. They are then drawn at 70-120°C with a drawing ratio of 2-5 times and heat-set. Curling and cutting: The shaped filaments are fed into a crimping machine and mechanically extruded to form wavy crimps; finally, they are cut by a cutting machine to obtain polylactic acid hollow fibers.

[0028] Ultimately, the resulting polylactic acid hollow fiber has a tensile strength of 3.7~5.2 cN / dtex and an elongation elastic recovery rate of 80~95%.

[0029] The preparation method in this embodiment avoids the hydrolytic degradation of PLA during subsequent high-temperature processing by deep drying and dehumidification; the temperature gradient design from the barrel to the spinneret ensures stable plasticization and full homogenization of the mixture system, and finally extrudes it from the hollow spinneret with optimal melt viscosity and elasticity; the metering pump ensures that the wall thickness and diameter of each hollow fiber are extremely uniform, which is the basis for obtaining consistent mechanical properties and resilience; rapid cooling (side / circular air blowing) forms an amorphous structure with a certain degree of orientation that is conducive to subsequent drawing, ultimately resulting in a polylactic acid hollow fiber breaking strength of 3.7~5.2 cN / dtex; and an elongation elastic recovery rate of 80~95%, which takes into account both excellent long-lasting bulkiness and good mechanical properties, making it have broad application prospects.

[0030] To further understand the solution of this application, the following embodiments and comparative examples are provided: Example 1 A durable, resilient polylactic acid (PLA) filler material comprises the following components in parts by weight: 50 parts polylactic acid; 30 parts PBAT; 15 parts TPU elastomer; 0.7 parts antioxidant 168; 4 parts nucleating agent starch; and 0.3 parts branching agent citric acid (CA). The preparation process is as follows: (1) Mixing: Mix polylactic acid material, modified filler, polyurethane additive, antioxidant, nucleating agent and branching agent in proportion, stir evenly, and extrude the mixture at 190°C through a twin-screw extruder to obtain modified polylactic acid chips. (2) Drying and pre-crystallization: The modified polylactic acid chips were put into a drying tower and dried at 100°C and vacuum degree -0.09MPa for 8 hours to keep the moisture content below 70ppm; (3) Melt metering extrusion: The dried particles are fed into the barrel and melted by a twin-screw extruder at 200°C. They are then extruded from the extrusion die at 210°C, filtered by a filter device, and then metered and transported to a spinning assembly with a special hollow spinneret at 220°C by a metering pump. After being extruded through the spinneret holes, the spinneret is rapidly cooled and solidified by side blowing or ring blowing to form a primary filament with a hollow structure. (4) Bundling and stretching: Multiple nascent filaments are bundled together by a guide and fed into a stretching machine. They are then stretched at 120°C with a stretching ratio of 5 and heat-set. (5) Curling and cutting: The shaped filaments are fed into a crimping machine and formed into a wavy crimp by mechanical extrusion; finally, they are cut by a cutting machine to obtain polylactic acid hollow short fibers.

[0031] Example 2 The basic structure is the same as in Example 1, except that the durable and resilient polylactic acid filler material includes the following components in parts by weight: 60 parts polylactic acid; 25 parts PBAT; 10 parts waterborne polyurethane resin; 0.7 parts antioxidant 1010; 1.3 parts nucleating agent cellulose nanocrystals (CNC); and 3 parts glycerol. The preparation method is exactly the same as in Example 1.

[0032] Example 3 The basic structure is the same as in Example 1, except that the durable and resilient polylactic acid filler material includes the following components in parts by weight: 70 parts polylactic acid; 20 parts PBAT; 5 parts cast polyurethane elastomer (CPU); 0.3 parts antioxidant 168; 0.3 parts antioxidant 1010; 2 parts nucleating agent chitosan; and 2.4 parts epoxidized soybean oil (ESO). The preparation method is exactly the same as in Example 1.

[0033] Example 4 The basic structure is the same as in Example 1, except that the durable and resilient polylactic acid filler material includes the following components in parts by weight: 75 parts polylactic acid; 15 parts PBAT; 5 parts thermoplastic polyurethane elastomer (TPU); 0.3 parts antioxidant 168; 0.3 parts antioxidant 1010; 3.4 parts nucleating agent dibenzyl sorbitol; and 1 part hexamethylene diisocyanate (HDI). The preparation method is exactly the same as in Example 1.

[0034] Comparative Example 1 It is basically the same as Example 1, except that this durable and resilient polylactic acid filler material contains only 100 parts of polylactic acid.

[0035] Comparative Example 2 The process is basically the same as in Example 1, except that the durable and resilient polylactic acid filler material includes the following components in parts by weight: 75 parts polylactic acid; 20 parts PBAT; 0.3 parts antioxidant 168; 0.3 parts antioxidant 1010; 3.4 parts nucleating agent dibenzyl sorbitol; and 1 part hexamethylene diisocyanate (HDI). The preparation method is exactly the same as in Example 1.

[0036] Comparative Example 3 The process is basically the same as in Example 1, except that the durable and resilient polylactic acid filler material includes the following components in parts by weight: 90 parts polylactic acid; 5 parts thermoplastic polyurethane elastomer (TPU); 0.3 parts antioxidant 168; 0.3 parts antioxidant 1010; 3.4 parts nucleating agent dibenzyl sorbitol; and 1 part hexamethylene diisocyanate (HDI). The preparation method is exactly the same as in Example 1.

[0037] The fibers obtained in Examples 1-4 and Comparative Examples 1-3 were tested for their breaking strength and elastic recovery rate at a given elongation, and the results are shown in Table 1 below: Table 1 Performance Data Sheet

[0038] As shown in Table 1, Comparative Examples 2 and 3 both involved adding a single modified filler or a single polyurethane elastomer for improvement. However, the improvement of a single component limits the scope of elasticity improvement, and the effect is not significant. In contrast, the scheme of this application, as in Examples 1 to 4, utilizes the entropic elastic deformation of the soft segments of the polyurethane elastomer to absorb energy, thereby improving the resilience and reducing plastic deformation. Combined with the synergistic effect of PBAT, this ultimately improves the material's resilience, resulting in soft, fluffy fibers and significantly reducing the frequency of spinning breakage, thus promoting the development of the environmentally friendly and biodegradable materials market.

[0039] The examples described herein are merely preferred embodiments of the invention and are not intended to limit the concept and scope of the invention. Any modifications and improvements made by those skilled in the art to the technical solutions of the invention without departing from the design concept of the invention should fall within the protection scope of the invention.

Claims

1. A durable, resilient polylactic acid filler material, characterized in that: The filling material is polylactic acid hollow fiber, including main base material and auxiliary materials: The main base material is polylactic acid; the auxiliary materials include polyurethane elastomer, modified filler, antioxidant, nucleating agent and branching agent; wherein, the weight ratio of polyurethane elastomer to main base material in the auxiliary materials is (0.06~0.3):1; the weight ratio of modified filler to main base material in the auxiliary materials is (0.2~0.6):1; the molecular weight of polylactic acid in the main base material is 100,000~150,000; The product comprises the following components in parts by weight: 50-75 parts polylactic acid; 15-30 parts modified filler; 5-15 parts polyurethane elastomer; 0.3-0.7 parts antioxidant; 1.3-4 parts nucleating agent; and 0.3-3 parts branching agent. The modified filler is polybutylene adipate terephthalate; the polyurethane elastomer is one or two of waterborne polyurethane resin, thermoplastic polyurethane elastomer, or cast polyurethane elastomer.

2. The durable, resilient polylactic acid filler material according to claim 1, characterized in that: The antioxidant is one or two of antioxidant 168 and antioxidant 1010; the nucleating agent is one or two of starch, cellulose nanocrystals, chitosan, and dibenzylidene sorbitol; the branching agent is one or two of citric acid, glycerol, epoxidized soybean oil, and hexamethylene diisocyanate.

3. A method for preparing a durable, resilient polylactic acid filler material as described in any one of claims 1-2, characterized in that: Includes the following steps: Raw material mixing: The main base material and auxiliary materials are mixed evenly to obtain a mixture; Slices: The mixture is extruded and pelletized at 165~190℃ using a twin-screw extruder to obtain modified polylactic acid chips; Drying and pre-crystallization: Modified polylactic acid chips are placed in a drying tower for drying; Preparation of primary growth filaments with hollow structures: The dried modified polylactic acid chips were sequentially subjected to heating and melting, precise extrusion, and rapid cooling to obtain primary growth filaments with hollow structures; Bundling and drawing: Multiple nascent filaments are bundled together by a guide and fed into a drawing machine. They are then drawn at 70-120°C with a drawing ratio of 2-5 times and heat-set. Curling and cutting: The shaped filaments are fed into a crimping machine and mechanically extruded to form wavy crimps; Finally, it is cut by a cutting machine to obtain polylactic acid hollow fibers.

4. The method for preparing a durable, resilient polylactic acid filler material according to claim 3, characterized in that: During the drying and pre-crystallization process, the drying parameters are as follows: drying at 80~100℃ and vacuum degree -0.08~-0.09MPa for 4~8 hours to control the moisture content below 70ppm.

5. The method for preparing a durable, resilient polylactic acid filler material according to claim 3, characterized in that: The specific steps for preparing nascent filaments with a hollow structure include: feeding dried particles into a barrel, melting them in a twin-screw extruder at 160-200°C, extruding them from an extrusion die at 170-210°C, filtering them through a filter device, and then metering and conveying the melt to a spinning assembly with a hollow spinneret at 185-220°C. After being extruded through the spinneret orifice, the melt is rapidly cooled and solidified by side blowing or ring blowing to form nascent filaments with a hollow structure.

6. The method for preparing a durable, resilient polylactic acid filler material according to claim 3, characterized in that: The obtained polylactic acid hollow fibers have a tensile strength of 3.7~5.2 cN / dtex and an elongation elastic recovery rate of 80~95%.

Images