Functional polylactic acid fiber production device and process thereof

Abstract

The application provides a functional polylactic acid fiber production device and a process thereof, relates to the field of synthetic fiber spinning, and comprises a bamboo micro-nano treatment unit, a bamboo carbon nanofiber preparation unit, a functional composite master batch preparation unit, a one-step melt spinning forming unit and an online stretching setting and winding unit. The one-step melt spinning forming unit comprises a single-screw extruder, a static mixing and filtering device and a heat preservation spinning box which are sequentially connected through heat preservation pipelines along the melt flow direction. The heat preservation spinning box is internally provided with a high-precision gear metering pump and a spinning assembly. The single-screw extruder comprises a double feeding groove, a feeding limiting piece, a screw body and a double-groove feeding mechanism. The feeding limiting piece is fixedly connected above the rear end of the single-screw extruder. The screw body is rotatably connected in the single-screw extruder. The problems of the feeding channel blockage of a single raw material, the shutdown of a feeding unit or the abnormal fluctuation of a feeding amount are solved.

Description

Technical Field

[0001] This invention relates to the field of synthetic fiber spinning technology, and in particular to a functional polylactic acid fiber production apparatus and process. Background Technology

[0002] With the advancement of global "dual carbon" goals and increased efforts to control white pollution, bio-based biodegradable polymer materials have become a research and industrialization hotspot in the materials field. Polylactic acid (PLA) is an aliphatic polyester material prepared from renewable plant resources such as corn and cassava through bio-fermentation and chemical synthesis. It has complete biodegradability, excellent biocompatibility, and mechanical properties and spinnability close to those of polyester fibers. After being discarded, it can be completely degraded into carbon dioxide and water in the natural environment without environmental residue. It is known as the "green and environmentally friendly material of the 21st century" and has been widely used in packaging, medical, textile and other fields. In the textile fiber field, polylactic acid fiber has become one of the core categories to replace petroleum-based polyester and nylon fiber due to its skin-friendly and breathable, antibacterial and mildew-proof, and completely degradable properties.

[0003] The present invention, CN102529056B, discloses a method for preparing high melt strength polylactic acid and an extruder. The raw materials are 100 parts by weight of polylactic acid resin, 1-3 parts by weight of a reactive chain extender, and 0.1-3 parts by weight of an antioxidant. After drying the polylactic acid resin, it is mixed with the reactive chain extender and antioxidant according to the above weight proportions, and then added to an extruder. The mixture is then reacted and extruded to obtain high melt strength polylactic acid. The extruder includes a first-stage extruder and a second-stage extruder, both equipped with temperature sensors and heating devices. The first-stage extruder is a twin-screw extruder, and the second-stage extruder is a single-screw extruder. The first-stage extruder has a first inlet and a first outlet, and the second extruder has a second inlet and a second outlet. The first outlet is connected to the second inlet. The above method can provide a production method and equipment for preparing polylactic acid materials with high melt strength and suitable for continuous large-scale production using a dual-single series reactive extruder structure.

[0004] However, in the melt processing of functional polylactic acid (PLA) fibers, the screw extruder is the core equipment for realizing the blending and plasticization of PLA matrix with various functional fillers and additives. The processing relies on the precise proportioning and continuous and stable synergistic feeding of multiple raw material systems such as PLA chips and functional modified components to ensure process stability. In actual production, due to the differences in the physical properties of multiple raw materials (such as particle size, flowability, and hygroscopicity) and fluctuations in the operating conditions of the feeding system, problems such as blockage of the feeding channel of a single raw material, shutdown of the feeding unit, or abnormal fluctuations in the feeding amount are very likely to occur. This directly leads to the raw material ratio in the extruder deviating from the process design value, affecting the product processing quality and batch stability. Summary of the Invention

[0005] In view of this, the present invention provides a functional polylactic acid (PLA) fiber production device and process, which features a closed-loop production system that integrates the high-value utilization of bamboo waste into the preparation of functional PLA fibers. Using bamboo charcoal nanofibers as biomass-modified fillers, it simultaneously addresses the industry pain points of ordinary PLA fibers, such as limited functionality and poor heat resistance. The entire process is green and environmentally friendly, meeting the requirements of sustainable development. Through a one-step melt spinning and online stretching and setting design, it replaces the cumbersome traditional two-step spinning process, significantly shortening the production process, reducing energy consumption and labor costs, and avoiding thermal degradation caused by repeated heating of PLA. The system also includes a three-stage filtration system. The static mixing integrated equipment effectively improves melt uniformity, reduces spinneret blockage and filament breakage, and significantly improves production stability and yield. The specially designed dual-feeder mechanism enables precise separate feeding of polylactic acid base chips and functional masterbatches. The anti-bridging and anti-backflow structures ensure continuous and stable feeding. The automatic stop-and-cut-off linkage structure solves the core problem of raw material imbalance and product quality decline caused by single raw material interruption and blockage.

[0006] This invention provides a functional polylactic acid fiber production apparatus and process, specifically including a bamboo micro-nano processing unit, a bamboo charcoal nanofiber preparation unit, a functional composite masterbatch preparation unit, a one-step melt spinning unit, and an online stretching, shaping, and winding unit; the one-step melt spinning unit includes a single-screw extruder, a static mixing and filtering equipment, and a heat-insulated spinning box, which are sequentially connected along the melt flow direction through heat-insulated pipelines. The heat-insulated spinning box is internally equipped with a high-precision gear metering pump and a spinning assembly. The lower part of the spinning assembly... The single-screw extruder is equipped with a ring-blowing cooling device and a fiber oiling device in sequence. It includes a double feed trough, a feed limiting component, a screw body, and a double feed trough feeding mechanism. Two sets of double feed troughs are provided, each fixedly connected to the upper rear end of the single-screw extruder. The feed limiting component is fixedly connected to the upper rear end of the single-screw extruder, with its lower end communicating with the interior of the extruder and its upper end communicating with the two sets of double feed troughs. The screw body is rotatably connected to the interior of the single-screw extruder.

[0007] Furthermore, the bamboo micro-nano processing unit includes a washing and crushing machine, an enzymatic hydrolysis reactor, a high-speed disperser, a high-pressure homogenizer, a centrifugal dehydrator, and a spray dryer, which are connected in sequence through a material conveying device.

[0008] Furthermore, the bamboo charcoal nanofiber preparation unit includes a vacuum carbonization furnace, an ultra-micro airflow pulverizer, a grading and screening machine, and a sealed storage tank, which are connected in sequence through a material conveying device.

[0009] Furthermore, the functional composite masterbatch preparation unit includes a loss-in-weight weighing scale, a high-speed mixer, a twin-screw extruder, a circulating water cooling tank, a water-cooled string pelletizer, a vibrating screen, a vacuum drum dryer, and a sealed storage silo, which are connected in sequence through a material conveying device.

[0010] Furthermore, the online stretching, shaping, and winding unit includes a guide roller group, a preheating roller, a primary stretching roller, a secondary stretching roller, a shaping roller, and a high-speed winding machine arranged sequentially along the fiber running direction.

[0011] Furthermore, the static mixing filtration equipment is equipped with three-stage filtration units: a coarse filtration unit, a fine filtration unit, and an ultrafine filtration unit.

[0012] Furthermore, the dual-feed trough feeding mechanism includes: a feeding section, a barrier compression section, a mixing section, a homogenization metering section, an anti-bridging motor, and an anti-bridging lever; the feeding section is located at the rear end of the screw body and is connected to the feeding limiter; the barrier compression section is located inside the screw body; the mixing section is located inside the screw body, and the mixing section is sequentially provided with pin-type mixing elements and pineapple head mixing structures along the melt flow direction; the homogenization metering section is located at the inner front end of the screw body, and the homogenization metering section has an equidistant and equal-depth thread structure; two sets of anti-bridging motors are provided, and the two sets of anti-bridging motors are respectively fixedly connected to the upper end of the dual feeding trough; the anti-bridging lever is coaxially fixedly connected below the output shaft of the anti-bridging motor, and the anti-bridging lever is located inside the lower end of the dual feeding trough.

[0013] Furthermore, the dual-feed trough feeding mechanism also includes: a limiting guide, a cutting-off drive, a first trigger, a second trigger, a feeding fixing component, a feeding anti-reverse baffle, and a feeding one-way baffle; the limiting guide is fixedly connected to the upper rear side of the single-screw extruder, and is positioned in front of the feeding limiting component; the cutting-off drive is an electromagnet structure, and is fixedly connected to the lower inner end of the limiting guide; two sets of the first trigger are provided, and the two sets of first triggers are respectively fixedly connected to the lower inner part of the dual-feed trough, with a contact structure at the lower end of the first trigger; two sets of the second trigger are provided. Both sets of second triggers are elastic metal sheet structures, and both sets of second triggers are fixedly connected to the lower part of the double feed trough. The upper end of both sets of second triggers is provided with a contact structure. The contact structures of both sets of second triggers and both sets of first triggers are electrically connected to the switching circuit of the cut-off drive component. The feed fixing component is fixedly connected to the inside of the feed limiting component. The feed anti-reverse baffle is hinged to the rear side of the feed fixing component. There are two sets of feed one-way baffles. The two sets of feed one-way baffles are fixedly connected to the upper left and right sides of the feed fixing component, and the rear ends of the two sets of feed one-way baffles are respectively set above the feed anti-reverse baffle.

[0014] Furthermore, the dual-feed trough feeding mechanism also includes: a stop driving component, a stop connecting spring, a stop guide wheel, and a stop transmission rope; the stop driving component is slidably connected to the upper part of the limiting guide component, and the stop driving component is magnetically connected to the cut-off driving component; the upper end of the stop connecting spring is fixedly connected to the stop driving component, and the lower end of the stop connecting spring is fixedly connected to the cut-off driving component; the stop guide wheel is rotatably connected to the front end of the feeding limiting component; the stop transmission rope is wrapped around the outer circumference of the stop guide wheel, the rear end of the stop transmission rope is fixedly connected to the feeding anti-reverse baffle, and the front end of the stop transmission rope is fixedly connected to the stop driving component.

[0015] Beneficial effects This invention constructs a closed-loop production system covering the entire process from bamboo waste pretreatment to the preparation of functional polylactic acid (PLA) fiber products. Through the synergistic cooperation of the bamboo micro-nano processing unit and the bamboo charcoal nanofiber preparation unit, the high-value utilization of agricultural and forestry waste is realized. The resulting bamboo charcoal nanofibers can simultaneously endow PLA fibers with antibacterial, far-infrared, and negative ion release functions, while improving the crystallization performance of PLA, thus solving the industry pain points of poor heat resistance and single function of ordinary PLA fibers. The supporting functional composite masterbatch preparation unit can achieve uniform blending of functional components with PLA matrix, effectively solving the problems of easy agglomeration of functional fillers and poor compatibility with the matrix, and preparing functional composite masterbatches with stable components and suitable for spinning requirements. This invention replaces the cumbersome process of traditional two-step spinning by linking a one-step melt spinning forming unit with an online stretching, shaping and winding unit. This significantly shortens the production process, reduces energy consumption and labor costs, and avoids thermal degradation caused by repeated heating and melting of polylactic acid. The matching static mixing and filtration equipment effectively reduces spinneret blockage and filament breakage through three-stage progressive filtration and secondary homogenization of the melt, significantly improving the spinning yield. This invention features a specially designed dual-feeder mechanism that achieves precise compartmentalized feeding of polylactic acid (PLA) base chips and functional masterbatches through two independent feeding channels, ensuring the accuracy of raw material proportions from the source. The accompanying anti-bridging component effectively breaks up raw material agglomeration, preventing inlet blockage and ensuring continuous and stable feeding. The one-way feed baffle and anti-reverse baffle prevent hot gas from rising from the barrel and high-temperature melt from returning, avoiding raw material agglomeration and premature thermal degradation. The automatic material cut-off linkage structure enables automatic detection of single-channel material cut-off and rapid sealing of the feeding channel, fundamentally solving the core problems of raw material proportion imbalance and product processing quality degradation caused by single-material material cut-off and blockage. Simultaneously, the four-section integrated structure of the screw body enables uniform melting and plasticizing of raw materials and efficient dispersion and mixing, preventing PLA shearing and overheating degradation, and providing a PLA composite melt with uniform composition and stable performance for the spinning process. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0017] The accompanying drawings described below are only related to some embodiments of the invention and are not intended to limit the invention.

[0018] In the attached diagram: Figure 1 This is a schematic diagram of the bamboo micro-nano processing unit structure of the present invention.

[0019] Figure 2 This is a schematic diagram of the bamboo charcoal nanofiber preparation unit structure of the present invention.

[0020] Figure 3 This is a schematic diagram of the functional composite masterbatch preparation unit structure of the present invention.

[0021] Figure 4 This is a schematic diagram of the one-step melt spinning forming unit structure of the present invention.

[0022] Figure 5 This is a schematic diagram of the online stretching, shaping, and winding unit structure of the present invention.

[0023] Figure 6 This is a schematic diagram of the anti-bridging motor structure of the present invention.

[0024] Figure 7 This is a schematic diagram of the barrier compression section structure of the present invention.

[0025] Figure 8 This is a schematic diagram of the limiting guide component structure of the present invention.

[0026] Figure 9 This is a schematic diagram of the anti-bridging lever structure of the present invention.

[0027] Figure 10 This is a schematic diagram of the second trigger structure of the present invention.

[0028] Figure 11 This is a schematic diagram of the feed anti-back baffle structure of the present invention.

[0029] List of reference numerals 1. Bamboo micro-nano processing unit; 2. Bamboo charcoal nanofiber preparation unit; 3. Functional composite masterbatch preparation unit; 4. One-step melt spinning unit; 401. Insulated spinning box; 5. Online stretching, shaping, and winding unit; 6. Single-screw extruder; 601. Double feed trough; 602. Feed limiter; 603. Screw body; 604. Feed section; 605. Barrier compression section; 606. Mixing section; 607. Homogenizer 608. Anti-bridging motor; 609. Anti-bridging lever; 610. Limiting guide; 611. Cut-off drive; 612. First trigger; 613. Second trigger; 614. Feed fixing component; 615. Feed anti-reverse baffle; 616. Feed one-way baffle; 617. Cut-off drive; 618. Cut-off connecting spring; 619. Cut-off guide wheel; 620. Cut-off transmission rope; 7. Static mixing and filtering equipment. Detailed Implementation

[0030] Example 1: Please refer to Figures 1 to 11 As shown: This invention provides a functional polylactic acid fiber production apparatus and process, including a bamboo micro-nano processing unit 1, a bamboo charcoal nanofiber preparation unit 2, a functional composite masterbatch preparation unit 3, a one-step melt spinning forming unit 4, and an online stretching, shaping, and winding unit 5; the one-step melt spinning forming unit 4 includes a single-screw extruder 6, a static mixing and filtering equipment 7, and an insulated spinning box 401 connected sequentially along the melt flow direction through an insulated pipeline. The insulated spinning box 401 is equipped with a high-precision gear metering pump and a spinning assembly, and a ring-blowing cooling system is sequentially arranged below the spinning assembly. The device includes a fiber oiling device; the single-screw extruder 6 includes a double feed trough 601, a feed limiting member 602, a screw body 603, and a double feed trough feeding mechanism; the double feed trough 601 is provided in two sets, and the two sets of double feed troughs 601 are respectively fixedly connected to the upper rear end of the single-screw extruder 6; the feed limiting member 602 is fixedly connected to the upper rear end of the single-screw extruder 6, the lower end of the feed limiting member 602 is connected to the inside of the single-screw extruder 6, and the upper end of the feed limiting member 602 is connected to the two sets of double feed troughs 601; the screw body 603 is rotatably connected to the inside of the single-screw extruder 6.

[0031] Among them, the bamboo micro-nano processing unit 1 includes a washing and crushing machine, an enzymatic hydrolysis reactor, a high-speed disperser, a high-pressure homogenizer, a centrifugal dehydrator and a spray dryer, which are connected in sequence through a material conveying device.

[0032] The bamboo charcoal nanofiber preparation unit 2 includes a vacuum carbonization furnace, an ultra-micro airflow pulverizer, a grading and screening machine, and a sealed storage tank, which are connected in sequence through a material conveying device.

[0033] The functional composite masterbatch preparation unit 3 includes: a loss-in-weight weighing scale, a high-speed mixer, a twin-screw extruder, a circulating water cooling tank, a water-cooled strip pelletizer, a vibrating screen, a vacuum drum dryer, and a sealed storage silo, which are connected in sequence through a material conveying device.

[0034] The online stretching, shaping, and winding unit 5 includes: a guide roller group, a preheating roller, a primary stretching roller, a secondary stretching roller, a shaping roller, and a high-speed winding machine arranged sequentially along the fiber running direction.

[0035] The static mixing filtration equipment 7 includes a three-stage filtration unit: a coarse filtration unit, a fine filtration unit, and an ultrafine filtration unit.

[0036] Specific usage method and function of this embodiment: The raw materials are cleaned and crushed by a cleaning crusher to complete cleaning, impurity removal, crushing and powder making, obtaining bamboo powder meeting the pre-treatment requirements. The bamboo powder, PDADMAC, composite bio-enzyme, and deionized water are sent into an enzymatic hydrolysis reactor together to complete the pre-treatment reaction for breaking cellulose hydrogen bonds. After the pre-treated materials are washed and centrifuged, they are sent into a high-speed disperser to complete preliminary dispersion and defibration, preparing a bamboo pulp suspension. The bamboo pulp suspension is sent into a high-pressure homogenizer to complete high-pressure micro-nano processing, releasing cellulose microfibrils, and obtaining a bamboo nano-cellulose suspension. After the suspension is concentrated and dehydrated by a centrifugal dehydrator, it is sent into a spray dryer for drying, obtaining powdery bamboo nano-cellulose, completing all process steps of the bamboo micro-nano processing unit 1. The obtained bamboo nano-cellulose is sent into the bamboo carbon nano-fiber preparation unit 2. The bamboo nano-cellulose is sent into a vacuum carbonization furnace, and the whole process heat treatment of pre-carbonization, carbonization, and high-temperature graphitization is completed through programmed temperature control, obtaining a primary bamboo carbon product. The primary bamboo carbon product is sent into an ultrafine air-flow pulverizer to complete ultrafine pulverization, obtaining nano-scale bamboo carbon powder. The pulverized powder is sent into a grading and screening machine to complete nano-scale particle size grading and screening, removing large particle aggregates, obtaining bamboo carbon nano-fibers with uniform particle size. The qualified bamboo carbon nano-fibers are sent into a sealed storage tank to complete nitrogen protection and sealed storage, completing all process steps of the bamboo carbon nano-fiber preparation unit 2. The obtained bamboo carbon nano-fibers, together with polylactic acid chips, PEG, PHBV, compatibilizer, dispersant, and antioxidant, are sent into the functional composite masterbatch preparation unit 3. All raw materials are accurately weighed and proportioned by multiple independent loss-in-weight metering scales according to the process formula. The proportioned raw materials are sent into a high-speed mixer to complete uniform pre-mixing at room temperature. The uniformly mixed materials are sent into a twin-screw extruder to complete melt blending and plasticization, realizing the uniform dispersion of functional components in the polylactic acid matrix. The extruded molten material strip is sent into a circulating water cooling tank to complete cooling and shaping, and then sent into a water-cooled draw bead granulator to complete granulation, obtaining primary masterbatch. The primary masterbatch is sent into a vibrating screening machine to complete grading and screening, removing unqualified particles, and then sent into a vacuum rotary drum dryer to complete deep drying, controlling the moisture content within the spinning requirement range. The dried qualified functional composite masterbatch is sent into a sealed storage bin to complete nitrogen protection and sealed storage, completing all process steps of the functional composite masterbatch preparation unit 3. The polylactic acid fiber-forming base chips and the functional composite masterbatch are sent into the one-step melt spinning forming unit 4. The polylactic acid fiber-forming base chips and the functional composite masterbatch are respectively sent into two double-feed troughs 601 supporting a single-screw extruder 6. The loss-in-weight metering feeder of the double-feed trough feeding mechanism accurately controls the feeding ratio and rate. The raw materials are uniformly sent into the internal cavity of the single-screw extruder 6 through the feeding limiting member 602. Inside the single-screw extruder 6, the raw materials complete transportation, melt plasticization, dispersion and mixing, and pressure stabilization and metering along with the rotation of the screw body 603, obtaining a polylactic acid composite melt with uniform components and stable temperature. The polylactic acid composite melt is sent into a static mixing and filtering device 7 through a heat preservation pipeline, and successively completes three-stage progressive filtering through the internal coarse filtering unit, fine filtering unit, and ultra-fine filtering unit.The melt undergoes secondary homogenization via a built-in static mixing unit to remove impurities and agglomerates, further improving melt uniformity. The filtered and homogenized melt is then fed into an insulated spinning box 401 via an insulated pipeline. After precise metering by a high-precision gear metering pump within the box, it is fed into the spinning assembly for melt stream extrusion. The extruded melt stream is cooled and solidified by a ring-blowing cooling device to produce continuous nascent fibers. The nascent fibers are then surface-oiled by a fiber oiling device and fed into an online stretching, shaping, and winding unit 5. The nascent fibers then pass through a guide roller assembly... After guiding and stabilizing the tension, the fiber is fed into a preheating roller to preheat it, preparing it for subsequent stretching. The preheated fiber then undergoes two stages of online stretching via a primary stretching roller and a secondary stretching roller, achieving the oriented crystallization of the fiber molecular chains and reaching the designed total stretch ratio. The stretched fiber is then fed into a setting roller for relaxation heat setting, eliminating internal stress and stabilizing fiber dimensions and properties. The set fiber is then precisely wound into shape by a high-speed winding machine, producing functional polylactic acid (PLA) FDY filament in one step, completing the entire production process.

[0037] Example 2: like Figures 1 to 11 As shown: Based on Embodiment 1, it also includes a dual-feed trough feeding mechanism. The dual-feeder mechanism includes: a feeding section 604, a barrier compression section 605, a mixing section 606, a homogenization metering section 607, an anti-bridging motor 608, and an anti-bridging lever 609. The feeding section 604 is located at the rear end of the screw body 603 and is connected to the feeding limiter 602. The barrier compression section 605 is located inside the screw body 603. The mixing section 606 is located inside the screw body 603 and extends along the melt flow direction. The secondary assembly includes a pin-type mixing element and a pineapple head mixing structure; the homogenization metering section 607 is located on the inner front end of the screw body 603, and the homogenization metering section 607 has an equidistant and equal-depth thread structure; two sets of anti-bridging motors 608 are provided, and the two sets of anti-bridging motors 608 are respectively fixedly connected to the upper end of the double feed trough 601; the anti-bridging lever 609 is coaxially fixedly connected to the lower part of the output shaft of the anti-bridging motor 608, and the anti-bridging lever 609 is located at the lower end of the inner part of the double feed trough 601.

[0038] The dual-feed trough feeding mechanism also includes: a limiting guide 610, a cutting-off drive 611, a first trigger 612, a second trigger 613, a feeding fixing component 614, a feeding anti-reverse baffle 615, and a feeding one-way baffle 616; the limiting guide 610 is fixedly connected to the upper rear side of the single-screw extruder 6, and is located in front of the feeding limiting component 602; the cutting-off drive 611 is an electromagnet structure, and is fixedly connected to the lower inner side of the limiting guide 610; two sets of first triggers 612 are provided, and the two sets of first triggers 612 are respectively fixedly connected to the lower inner side of the dual-feed trough 601, and the lower end of the first trigger 612 is provided with a contact structure; two sets of second triggers 613 are provided. Both sets of second triggers 613 are elastic metal sheet structures. Both sets of second triggers 613 are fixedly connected to the lower part of the double feed trough 601. The upper end of both sets of second triggers 613 is provided with a contact structure. The contact structures of both sets of second triggers 613 and both sets of first triggers 612 are electrically connected to the switching circuit of the cut-off drive component 611. The feed fixing component 614 is fixedly connected to the inside of the feed limiting component 602. The feed anti-reverse baffle 615 is hinged to the rear side of the feed fixing component 614. Two sets of feed one-way baffles 616 are provided. The two sets of feed one-way baffles 616 are fixedly connected to the upper left and right sides of the feed fixing component 614, respectively. The rear ends of the two sets of feed one-way baffles 616 are respectively set above the feed anti-reverse baffle 615.

[0039] The dual-feeder feeding mechanism also includes: a stop drive component 617, a stop connecting spring 618, a stop guide wheel 619, and a stop transmission rope 620; the stop drive component 617 is slidably connected to the upper part of the limit guide component 610, and the stop drive component 617 is magnetically connected to the stop drive component 611; the upper end of the stop connecting spring 618 is fixedly connected to the stop drive component 617, and the lower end of the stop connecting spring 618 is fixedly connected to the stop drive component 611; the stop guide wheel 619 is rotatably connected to the front end of the feed limit component 602; the stop transmission rope 620 is wrapped around the outer circumference of the stop guide wheel 619, the rear end of the stop transmission rope 620 is fixedly connected to the feed anti-reverse baffle 615, and the front end of the stop transmission rope 620 is fixedly connected to the stop drive component 617.

[0040] The specific usage and function of this embodiment: Polylactic acid fiber base chips and functional composite masterbatches are respectively fed into two independent double feed troughs 601. The double feed troughs 601 are connected to the feed section 604 of the screw body 603 through the feed limiting component 602. The anti-bridging motor 608 drives the anti-bridging lever 609 in the double feed troughs 601 to rotate at low speed, breaking up the bridging and agglomeration of raw materials, avoiding blockage of the feed inlet, and ensuring continuous and stable feeding of the two sets of raw materials. The raw materials pass through the feed one-way baffle 616 and the feed anti-reverse baffle on the feed fixing component 614. 615 falls into the feeding section 604, where the one-way feeding baffle 616 enables unidirectional feeding, preventing hot air from the barrel from rising and causing raw material agglomeration; the feed anti-reverse baffle 615 opens the feeding channel under the impact of raw material during normal feeding, and can automatically close and seal when melt backflow occurs, preventing high-temperature melt backflow from causing blockage and raw material degradation. The raw material entering the barrel rotates with the screw body 603, and is stably conveyed through the feeding section 604, gradually melted and plasticized in the barrier compression section 605, and mixed with the pineapple head compound by the pin-type mixing elements in the mixing section 606. The dispersion and homogenization section 607 outputs a stable voltage to obtain a polylactic acid composite melt with uniform composition. The melt is then sequentially fed into the static mixing and filtration equipment 7 and the heat-insulated spinning box 401 to complete the spinning and forming process. When any set of dual feed troughs 601 experiences a material interruption or severe insufficient feeding, the second trigger 613 in that trough loses the raw material pressure and rebounds, contacting the contact point of the first trigger 612, thus activating the control circuit of the cut-off drive 611 fixed in the limiting guide 610. The cut-off drive 611 is energized and generates magnetic force. The adsorption-stopping drive component 617 slides downwards, pulling the feed anti-reverse baffle 615 to close quickly via the stop transmission rope 620 that passes around the stop guide wheel 619, completely blocking the feed channel and preventing the raw material ratio from becoming unbalanced after material interruption. At the same time, it completely blocks the return of melt. After the material interruption fault is cleared, the stop drive component 611 loses power and the magnetic force disappears. The stop drive component 617 resets under the elastic force of the stop connecting spring 618. The stop transmission rope 620 is released, and the feed anti-reverse baffle 615 can reopen under the impact of the raw material, restoring normal feeding.

[0041] The following points should be noted in this article: 1. The accompanying drawings of this embodiment only involve the structures involved in this embodiment; other structures can refer to the general design.

[0042] 2. Where there is no conflict, this embodiment and the features in the embodiment can be combined with each other to obtain new embodiments.

[0043] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A functional polylactic acid fiber production apparatus, characterized in that: The system includes a bamboo micro-nano processing unit (1), a bamboo charcoal nanofiber preparation unit (2), a functional composite masterbatch preparation unit (3), a one-step melt spinning forming unit (4), and an online stretching, shaping, and winding unit (5). The one-step melt spinning forming unit (4) includes a single-screw extruder (6), a static mixing and filtering equipment (7), and a heat-insulated spinning box (401) connected sequentially along the melt flow direction through a heat-insulated pipeline. The heat-insulated spinning box (401) is equipped with a high-precision gear metering pump and a spinning assembly. Below the spinning assembly, a ring-blowing cooling device and a fiber oiling device are sequentially arranged. The single-screw extruder... (6) Includes a double feed trough (601), a feed limiting member (602), a screw body (603), and a double feed trough feeding mechanism; the double feed trough (601) is provided in two sets, and the two sets of double feed troughs (601) are respectively fixedly connected to the upper rear end of the single screw extruder (6); the feed limiting member (602) is fixedly connected to the upper rear end of the single screw extruder (6), the lower end of the feed limiting member (602) is connected to the inside of the single screw extruder (6), and the upper end of the feed limiting member (602) is connected to the two sets of double feed troughs (601); the screw body (603) is rotatably connected to the inside of the single screw extruder (6).

2. The functional polylactic acid fiber production apparatus as described in claim 1, characterized in that: The bamboo micro-nano processing unit (1) includes a washing and crushing machine, an enzymatic hydrolysis reactor, a high-speed disperser, a high-pressure homogenizer, a centrifugal dehydrator and a spray dryer connected in sequence through a material conveying device.

3. The functional polylactic acid fiber production apparatus as described in claim 1, characterized in that: The bamboo carbon nanofiber preparation unit (2) includes a vacuum carbonization furnace, an ultra-micro airflow pulverizer, a grading sieve and a sealed storage tank connected in sequence by a material conveying device.

4. The functional polylactic acid fiber production apparatus as described in claim 1, characterized in that: The functional composite masterbatch preparation unit (3) includes a loss-in-weight weighing scale, a high-speed mixer, a twin-screw extruder, a circulating water cooling tank, a water-cooled strip pelletizer, a vibrating screen, a vacuum drum dryer, and a sealed storage silo, which are connected in sequence through a material conveying device.

5. The functional polylactic acid fiber production apparatus as described in claim 1, characterized in that: The online stretching, shaping, and winding unit (5) includes a guide roller group, a preheating roller, a first-stage stretching roller, a second-stage stretching roller, a shaping roller, and a high-speed winding machine arranged sequentially along the fiber running direction.

6. The functional polylactic acid fiber production apparatus as described in claim 1, characterized in that: The static mixing filtration equipment (7) is equipped with three-stage filtration units, namely a coarse filtration unit, a fine filtration unit and an ultrafine filtration unit.

7. The functional polylactic acid fiber production apparatus as described in claim 1, characterized in that: The dual-feeder mechanism includes: a feeding section (604), a barrier compression section (605), a mixing section (606), a homogenization metering section (607), an anti-bridging motor (608), and an anti-bridging lever (609); the feeding section (604) is located at the rear end of the screw body (603), and the feeding section (604) is connected to the feeding limiter (602); the barrier compression section (605) is located on the inner side of the screw body (603); the mixing section (606) is located on the inner side of the screw body (603), and the mixing section (606) runs along the melt. The flow direction is sequentially provided with pin-type mixing elements and pineapple head mixing structures; the homogenization metering section (607) is located at the inner front end of the screw body (603), and the homogenization metering section (607) is an equidistant and equal-depth thread structure; two sets of anti-bridging motors (608) are provided, and the two sets of anti-bridging motors (608) are respectively fixedly connected to the upper end of the double feed trough (601); the anti-bridging lever (609) is coaxially fixedly connected to the lower part of the output shaft of the anti-bridging motor (608), and the anti-bridging lever (609) is located at the lower end of the inner part of the double feed trough (601).

8. The functional polylactic acid fiber production apparatus as described in claim 7, characterized in that: The dual-feed trough feeding mechanism further includes: a limiting guide (610), a cutting-off drive (611), a first trigger (612), a second trigger (613), a feeding fixing component (614), a feeding anti-reverse baffle (615), and a feeding one-way baffle (616); the limiting guide (610) is fixedly connected to the upper rear side of the single-screw extruder (6), and the limiting guide (610) is located in front of the feeding limiting component (602); the cutting-off drive (611) is an electromagnet structure, and the cutting-off drive (611) is fixedly connected to the lower inner side of the limiting guide (610); the first trigger (612) is provided in two sets, and the two sets of first triggers (612) are respectively fixedly connected to the lower inner side of the dual-feed trough (601), and the lower end of the first trigger (612) is provided with a contact structure; the second trigger (613) is provided in two sets. Two sets of second triggers (613) are provided. Both sets of second triggers (613) are elastic metal sheet structures. Both sets of second triggers (613) are fixedly connected to the lower part of the double feed trough (601). The upper end of both sets of second triggers (613) is provided with a contact structure. The contact structures of both sets of second triggers (613) and both sets of first triggers (612) are electrically connected to the switching circuit of the cut-off drive (611). The feed fixing component (614) is fixedly connected to the inside of the feed limiting component (602). The feed anti-reverse baffle (615) is hinged to the rear side of the feed fixing component (614). Two sets of feed one-way baffles (616) are provided. The two sets of feed one-way baffles (616) are fixedly connected to the upper left and right sides of the feed fixing component (614). The rear ends of the two sets of feed one-way baffles (616) are respectively set above the feed anti-reverse baffles (615).

9. The functional polylactic acid fiber production apparatus as described in claim 8, characterized in that: The dual-feeder feeding mechanism further includes: a stop drive (617), a stop connecting spring (618), a stop guide wheel (619), and a stop transmission rope (620); the stop drive (617) is slidably connected to the inside upper part of the limiting guide (610), and the stop drive (617) is magnetically connected to the stop drive (611); the upper end of the stop connecting spring (618) is fixedly connected to the stop drive (617). The lower end of the stop connecting spring (618) is fixedly connected to the stop driving member (611); the stop guide wheel (619) is rotatably connected to the front end of the feed limiting member (602); the stop transmission rope (620) is wrapped around the outer circumference of the stop guide wheel (619), the rear end of the stop transmission rope (620) is fixedly connected to the feed anti-reverse baffle (615), and the front end of the stop transmission rope (620) is fixedly connected to the stop driving member (617).

10. The production process for functional polylactic acid fibers as described in claim 1, characterized in that: S1. Micro-nano treatment of bamboo waste to prepare bamboo nanocellulose: Using bamboo processing waste as raw material, bamboo powder is obtained by washing and crushing. Bamboo powder, PDADMAC, compound biological enzyme and deionized water are added to an enzymatic hydrolysis reactor. The pH value of the system is adjusted to 4.5-6.0, and the reaction is carried out at a constant temperature of 45-55℃ for 12-24 hours to complete the pretreatment. The pretreated material is washed with water and centrifuged to prepare a bamboo pulp suspension. After high-speed dispersion and high-pressure homogenization micro-nano treatment, bamboo nanocellulose suspension is obtained. After dehydration and drying, powdered bamboo nanocellulose is obtained. S2. Preparation of bamboo charcoal nanofibers: The bamboo nanocellulose obtained in step S1 is fed into a vacuum carbonization furnace, an inert protective gas is introduced, and high-temperature carbonization and graphitization are carried out using programmed temperature control. After cooling, the primary bamboo charcoal product is obtained, and then it is subjected to ultra-fine grinding and grading sieving to obtain bamboo charcoal nanofibers. S3. Preparation of functional composite masterbatch: Weigh 65-85 parts of polylactic acid chips, 5-20 parts of bamboo charcoal nanofibers, 2-8 parts of PEG, 3-10 parts of PHBV, 1-3 parts of compatibilizer, 0.5-2 parts of dispersant, and 0.1-1 parts of antioxidant according to the mass ratio. After high-speed mixing, melt blending extrusion, pelletizing, and drying, the functional composite masterbatch is obtained. S4. One-step melt spinning: Polylactic acid fiber base chips and functional composite masterbatch obtained in step S3 are fed into a single screw extruder (6) at a mass ratio of 85-95:5-15 and melt-blended to obtain polylactic acid composite melt; after being filtered and homogenized by static mixing and filtration equipment (7), the composite melt is sent to a heat-insulated spinning box, metered by a metering pump, extruded by a spinning assembly, and cooled and shaped by ring blowing to obtain nascent fiber, which is then oiled and sent to an online stretching, shaping and winding unit (5). S5. Online stretching, setting and winding: After the oiled nascent fibers are preheated, stretched and heat-set online in multiple stages, they are wound into shape in one step by a high-speed winding machine to obtain functional polylactic acid FDY filament products.

Images