Processing and manufacturing method for natural eucommia wood-plastic composite material
Through the fine pretreatment of Eucommia bark, fruit shell, leaves and wood and the gradient temperature control blending process, the problems of interface bonding and thermal stability of wood-plastic composite materials were solved, high-strength weather resistance and slow-release antibacterial function were achieved, and the overall performance of the material was improved.
Patent Information
- Application Number
- CN202510955128.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-11
- Publication Date
- 2025-10-17
AI Technical Summary
Existing wood-plastic composite materials have insufficient bonding strength at the fiber interface and poor thermal stability, which limits the improvement of the material's mechanical properties. In addition, the residues extracted from Eucommia ulmoides are not fully utilized, the resource recycling chain is broken, and it is difficult to meet the needs of high-end applications.
Through the fine pretreatment of Eucommia bark, fruit shell, leaves and wood, including high-pressure water washing, steam softening, microwave-induced colloid exudation and nano-modification, combined with gradient temperature control blending process, a uniform adhesive film and reinforced fiber bonding are formed, and alkali treatment and silane coupling agent are used to improve the interface performance.
It significantly improves the interfacial bonding strength and thermal stability between the fiber and the plastic matrix, achieves high-strength weather resistance, and has a sustained-release antibacterial function to meet high-end application needs.
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of wood-plastic composites, and specifically relates to a processing and manufacturing method for natural eucommia wood-plastic composites. BACKGROUND
[0002] Wood-plastic composites are a new type of environmentally friendly material, which has the characteristics of both plastics and wood, has the advantages of water resistance, corrosion resistance, insect resistance, dimensional stability, easy processing, etc., and can be 100% recycled and produced, without causing "white pollution". Wood-plastic composites are widely used in building materials, furniture, logistics packaging and other industries, and are an ideal choice to replace traditional wood and plastic.
[0003] As an environmentally friendly functional material, wood-plastic composites are traditionally prepared by using straw, bamboo and other conventional plant fiber raw materials, which has the problems of serious homogenization of raw materials and lack of active ingredients. In the prior art, the pretreatment of wood fibers is mainly mechanical crushing and simple drying, which leads to insufficient fiber interfacial bonding force and easy stress cracking of the product. The blending process of the thermoplastic matrix and the plant fibers often causes agglomeration defects due to uneven dispersion, which restricts the improvement of the mechanical properties of the material. Although polypropylene-based wood-plastic composites have achieved industrial application, their raw material system is still limited to ordinary wood powder filling, and the functional value of plant components cannot be fully utilized, especially in terms of antibacterial and weather-resistant additional properties. In view of the efficient utilization of eucommia resources, the existing technology focuses on the extraction of eucommia rubber and the development of medicinal ingredients, but lacks a deep utilization scheme for the waste components such as tree bark and fruit shells after extraction. Traditional residue treatment methods mainly include incineration and composting, which not only wastes lignin and polyphenolic active substances, but also breaks the resource recycling chain. The gum components remaining in the eucommia extraction residues still have great utilization space. Current research in the field of fiber activation is still dominated by acid and alkali treatment, and there is no systematic solution to the technology of gum exudation control and nano synergistic modification, which makes it difficult to meet the requirements of high-end application scenarios in terms of interfacial bonding strength and thermal stability of the composite material. Therefore, it is necessary to improve it. SUMMARY
[0004] In view of the deficiencies of the prior art, the application provides a processing and manufacturing method for natural eucommia wood-plastic composites, which has the advantages of high-strength weather resistance, slow-release antibacterial property and green regeneration.
[0005] To achieve the above-mentioned purpose, the application provides the following technical scheme: a processing and manufacturing method for natural eucommia wood-plastic composites, the specific steps are as follows:
[0006] Step 1: Raw material pretreatment
[0007] Bark processing: The rough outer skin of the collected Eucommia bark is manually peeled off, and the inner phloem part rich in Eucommia gum is retained. The bark is repeatedly washed with a high-pressure water gun to remove mud, insect eggs and residual impurities attached to the surface. The washed bark needs to be drained and spread in a ventilated place for preliminary drying;
[0008] Shell processing: The Eucommia ulmoides shells are crushed by mechanical crushing equipment to separate the hard shell and the inner membrane. The crushed shells are graded and screened using a vibrating screen to remove debris and dust with a particle size of less than 1 mm. The hard shells are used as raw materials after screening;
[0009] Leaf processing: manually remove the yellow and rotten leaves from the leaves, retain the intact green leaves, put the leaves into the rinsing tank, soak them in clean water for 2 hours and stir to remove soluble tannins. After rinsing, transfer them to the centrifuge for dehydration to reduce the subsequent drying energy consumption;
[0010] Eucommia wood processing: Remove the aging bark containing impurities on the surface of the Eucommia wood, retain the clean wood inside, use a planer to remove the remaining bark and rotten parts on the surface, place the wood segments in a steam tank, and steam with saturated steam (0.3MPa, 120℃) for 1.5 hours to reduce the lignin content and soften the fibers. Use a fiber separator to break down the softened wood into wood fiber bundles with a diameter of 0.5-2mm, and remove unseparated wood fragments;
[0011] Residue treatment: The residue after extracting Eucommia gum is separated into the gum film and the fiber matrix by an eddy current separator, and the residual fiber matrix is crushed to 80-100 mesh for the second time to obtain regenerated fiber powder for use;
[0012] Step 2: Drying
[0013] The processed fruit shells and leaves are spread flat on the tray and placed in the electric hot air drying oven for segmented drying;
[0014] The processed bark and wood fiber bundles are spread flat on the tray and placed in an electric heated air drying oven for segmented drying;
[0015] Use a rapid moisture meter to test until the moisture content of all raw materials is less than 3%;
[0016] Step 3: Crushing and Classification
[0017] The bark and husk are coarsely crushed by a hammer mill, first crushed into 20 mesh coarse powder, and then separated into 40 to 80 mesh fiber bundles by an air flow separator, and the unbroken coarse particles are removed and returned to the crushing machine;
[0018] The leaves are finely pulverized under nitrogen protection using a super micro pulverizer, the feeding speed and the gap between the cutter head are controlled, and finally 100-150 mesh ultrafine powder is obtained, which is sealed to avoid moisture absorption;
[0019] The wood fiber bundle is further refined by a disc type refiner, the gap between the grinding discs is adjusted to 0.1-0.3 mm, and wood short fibers with a length of 3-5 mm and a diameter of 0.1-0.5 mm are obtained;
[0020] Step four: fiber activation treatment
[0021] Alkali treatment strengthening: configure a 5% sodium hydroxide solution, immerse the bark, shell fiber and wood short fiber in the solution according to the solid-liquid ratio of 1:10, keep the temperature at 40 degrees Celsius for 2 hours, after treatment, neutralize with dilute hydrochloric acid to pH 7.0, then rinse with deionized water until the conductivity is less than 50 μS / cm, and dry for standby;
[0022] Microwave excitation gum exudation: mix the bark fiber and wood short fiber at a ratio of 1:1, lay them in the microwave treatment cavity, set the microwave power to 500 watts, and irradiate for 2 minutes. High-frequency electromagnetic waves make the molecular chain of eucommia rubber inside the fiber break and migrate, forming a uniform gum film on the surface of the fiber. Immediately after treatment, cool to room temperature with cold air to prevent gum oxidation;
[0023] Functional synergistic modification: mix the leaf ultrafine powder with 1%-3% composite filler in a mixer for 30 minutes. The composite filler is made of silica, calcium carbonate and titanium dioxide in a ratio of 1:0.5:0.3. The active ingredients in the leaves are loaded by the adsorption of nanoparticles to improve the thermal stability during subsequent processing;
[0024] Step five: blending modification process
[0025] Use a high-speed mixer to pre-mix the raw materials. Set the mixer speed to 1200 rpm. The mixing process is divided into three stages with sequential feeding:
[0026] First stage: put the biobased plastic particles and the corresponding compatibilizer into the mixer together. The biobased plastic particles include polyethylene, polypropylene, polyvinyl chloride, and polycarbonate. The compatibilizer uniformly coats the plastic in the molten state. The mixing time is 3 to 5 minutes;
[0027] Second stage: add the pretreated eucommia bark fiber, regenerated fiber powder, shell fiber and wood short fiber to the mixer in batches. Use a gradient mixing strategy. First, mix at low speed for 1 minute to disperse the fibers. Then gradually increase the speed to full speed for 5 to 8 minutes to ensure that the fibers are fully infiltrated with the molten plastic;
[0028] Third stage: Finally add the super-micro pulverized leaf powder and stearic acid lubricant, continue to mix for 2 to 3 minutes until all components form a homogeneous mixture;
[0029] Step six: extrusion molding
[0030] Use a co-rotating twin-screw extruder, divide the barrel into three temperature control zones, namely the feeding zone, the melting zone and the homogenization zone; the screw speed is adjusted to 200 to 250 revolutions per minute, and the high shear effect promotes the interface bonding of fibers and plastics; the die head pressure is maintained at 4 to 6 megapascals, and the melt impurities are filtered by a perforated plate; immediately after discharging from the die, enter the vacuum setting tank;
[0031] Place the extruded profile in an infrared heating furnace, and keep it at 80 degrees Celsius for 30 minutes to slowly release the internal residual stress of the material, and then naturally cool to room temperature.
[0032] Preferably, the three temperature control zones in step six are the feeding zone, the melting zone and the homogenization zone, wherein the feeding zone temperature is set to 120 degrees Celsius to ensure smooth material conveying; the melting zone temperature gradient is set to 160 to 170 degrees Celsius to melt the plastic in stages and achieve fiber dispersion; the homogenization zone temperature is controlled at 190 degrees Celsius to ensure that the melt is fully plasticized and not degraded.
[0033] Preferably, during the mixing process in step five, circulating heat conduction oil is introduced into the mixing machine jacket to control the material temperature below the plastic melting point.
[0034] Preferably, after the bark, shell fiber and wood short fiber are strengthened by alkali treatment in step four, prepare a silane coupling agent solution with a concentration of 1% to 2% in ethanol, uniformly spray it through a spraying device, and select one of KH550, KH570 or titanium ester NDZ-201 as the silane coupling agent, wherein KH550 is used for surface treatment of bark fiber, KH570 is used for shell fiber treatment, and titanium ester coupling agent is used for wood short fiber modification, and then perform drying treatment at a temperature of sixty degrees Celsius.
[0035] Preferably, before the third stage in step five, the surface modified nano zinc oxide is pre-mixed with the leaf powder by dry method, and then the pre-mixed nano zinc oxide and leaf powder mixture is added to the high-speed mixer together with the stearic acid lubricant.
[0036] Preferably, before the first stage in step five, the hydrophobically modified lignin and the bio-based plastic particles are added to the high-speed mixer together with the maleic anhydride grafted polyethylene compatibilizer, and when the plastic particles begin to melt, the lignin derivative gradually disperses into the plastic matrix under the action of shear force, forming a uniform blend system.
[0037] Preferably, the segmented drying of the fruit shells and leaves in step two is divided into an initial stage and a main stage, the initial stage is set at 60 degrees Celsius, and the surface free water is removed after drying for 2 hours; the main drying stage is heated to 80 degrees Celsius, and the drying is continued for 4 to 6 hours, and the material is turned over every 30 minutes to ensure uniform heating.
[0038] Preferably, the segmented drying of the bark and wood fiber bundles in step two is divided into an initial stage and a temperature rising stage, the initial stage is dried at 60 degrees Celsius for 3 hours, and the temperature rising stage is raised to 80 degrees Celsius for 6 hours.
[0039] Preferably, the water temperature of the vacuum shaping water tank in step six is controlled at 15 to 20 degrees Celsius to avoid material deformation caused by sudden cooling.
[0040] Compared with the prior art, the beneficial effects of the present application are as follows:
[0041] By exciting the gum inside the eucommia fiber to migrate and form a uniform gum film on the surface through microwaves, combined with the directional bonding of silane coupling agent and the functional modification technology of nano silicon dioxide, the interfacial bonding strength of the fiber and the plastic matrix and the thermal stability of the material are significantly improved; the three-stage gradient temperature control blending process is adopted to realize the full infiltration of the molten matrix to the fiber and the uniform loading of the active ingredients, effectively inhibiting the problems of fiber aggregation and thermal sensitive material decomposition in the traditional process, so that the composite material has excellent tensile strength and impact resistance, and also has the functions of slow-release antibacterial, weather-resistant and anti-aging, etc. DETAILED DESCRIPTION
[0042] Based on the examples in the present application, all other examples obtained by a person of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.
[0043] The embodiment of the present application provides a processing and manufacturing method for natural eucommia wood plastic composite material, and the specific steps are as follows:
[0044] Step one: raw material pretreatment
[0045] Bark treatment: the collected eucommia bark is manually stripped of the outer rough cuticle, and the inner phloem part rich in eucommia rubber is reserved; the bark is repeatedly washed by using a high-pressure water gun to remove the attached silt, insect eggs and residual impurities on the surface; and the washed bark needs to be drained of water and laid on a ventilated place for preliminary drying;
[0046] Fruit shell treatment: the eucommia fruit shell is broken by a mechanical rolling equipment, and the hard shell and the internal membrane are separated; the broken fruit shell is classified and screened by using a vibrating screen classifier, and the debris and dust with a particle size less than 1 millimeter are removed; and the hard shell after screening is used as a raw material;
[0047] Leaf processing: manually remove the yellow and rotten parts of the leaves, and keep the complete green leaves. Put the leaves into the rinsing pool, soak them in water for 2 hours, and stir them to remove the soluble tannins. After rinsing, transfer them to the centrifuge for dehydration, reducing the energy consumption of subsequent drying;
[0048] Eucommia wood processing: remove the aging bark containing impurities on the surface of Eucommia wood, and keep the clean wood inside. Use a planer to remove the residual bark and decayed parts on the surface. Put the wood segments into a steam tank, and pass saturated steam (0.3 MPa, 120℃) for 1.5 hours to reduce the lignin content and soften the fibers. Use a fiber separator to separate the softened wood into wood fiber bundles with a diameter of 0.5-2 mm, and remove the unseparated wood fragments;
[0049] Residue processing: separate the residue after extracting Eucommia rubber from the fiber matrix by a vortex separator, and further crush the residual fiber matrix to 80-100 mesh to obtain regenerated fiber powder for future use;
[0050] Step two: drying treatment
[0051] Lay the processed fruit shells and leaves flat in the trays, and put them into the electric heat air drying oven for staged drying;
[0052] Lay the processed bark and wood fiber bundles flat in the trays, and put them into the electric heat air drying oven for staged drying;
[0053] Use a rapid moisture meter to detect until the moisture content of all raw materials is less than 3%;
[0054] Step three: crushing and grading
[0055] Use a hammer crusher to coarsely crush the bark and fruit shells to 20 mesh coarse powder, and then separate the 40-80 mesh fiber bundles from the airflow separator, and remove the unbroken coarse particles for re-crushing;
[0056] Use a supermicro crusher to finely crush the leaves under nitrogen protection, control the feeding speed and gap between the cutter head, and finally obtain 100-150 mesh ultrafine powder, which is sealed to avoid moisture absorption;
[0057] Further refine the wood fiber bundles by a disc-type grinding machine, adjust the gap between the grinding discs to 0.1-0.3 mm, and obtain wood short fibers with a length of 3-5 mm and a diameter of 0.1-0.5 mm;
[0058] Step four: fiber activation treatment
[0059] Alkaline treatment reinforcement: A 5% sodium hydroxide solution is prepared, and the bark, shell fiber, and wood short fiber are immersed in the solution at a solid-liquid ratio of 1:10, kept at a constant temperature of 40 degrees Celsius for 2 hours, and then neutralized to a pH value of 7.0 with dilute hydrochloric acid. After treatment, rinse with deionized water until the conductivity is less than 50 μS / cm, and dry for use;
[0060] Microwave excitation of gum exudation: Mix the bark fiber and wood short fiber at a ratio of 1:1, lay them flat in the microwave treatment cavity, set the microwave power to 500 watts, and irradiate for 2 minutes. The high-frequency electromagnetic waves cause the molecular chains of eucommia gum inside the fiber to break and migrate, forming a uniform gum film on the surface of the fiber. Immediately after treatment, cool to room temperature with cold air to prevent gum oxidation;
[0061] Functional synergistic modification: Mix the leaf ultrafine powder with 1%-3% composite filler in a mixer for 30 minutes. The composite filler is made of silica, calcium carbonate, and titanium dioxide in a ratio of 1:0.5:0.3. The active ingredients in the leaves are loaded onto the nanoparticles through adsorption, improving the thermal stability during subsequent processing.
[0062] Step five: blending modification process
[0063] Use a high-speed mixer to pre-mix the raw materials. Set the mixer speed to 1200 revolutions per minute. The mixing process is divided into three stages, with the materials added in order:
[0064] First stage: Add the bio-based plastic particles and the corresponding compatibilizer to the mixer. The bio-based plastic particles include polyethylene, polypropylene, polyvinyl chloride, and polycarbonate. The compatibilizer uniformly coats the plastic in a molten state. The mixing time is 3 to 5 minutes.
[0065] Second stage: Add the pretreated eucommia bark fiber, regenerated fiber powder, shell fiber, and wood short fiber to the mixer in batches. Use a gradient mixing strategy. First, mix at low speed for 1 minute to disperse the fibers. Then gradually increase the speed to full speed for 5 to 8 minutes to ensure that the fibers are fully immersed in the molten plastic.
[0066] Third stage: Finally, add the ultra-finely ground leaf powder and stearic acid lubricant, and continue mixing for 2 to 3 minutes until all components form a homogeneous mixture.
[0067] Step six: extrusion molding
[0068] Use a co-rotating twin-screw extruder. Divide the extruder barrel into three temperature control zones: feeding zone, melting zone, and homogenization zone. Adjust the screw speed to 200 to 250 revolutions per minute. High shear promotes the interface bonding between the fibers and the plastic. Maintain the die head pressure at 4 to 6 megapascals. Use a multi-hole plate to filter the melt impurities. Immediately after the material exits the die, it enters the vacuum setting water tank.
[0069] The extruded profile is placed in an infrared heating furnace, and the residual stress in the material is slowly released at 80 degrees Celsius for 30 minutes, and then naturally cooled to room temperature.
[0070] By cleaning, drying and crushing the raw materials, then using lye to treat the fibers, microwave to stimulate the glue to exude and form a glue film, and nano-silicon dioxide to modify the leaf powder to improve thermal stability, three-stage high-speed mixing is used for blending modification: first, melt the plastic and mix with the compatibilizer, then add the fibers in batches to achieve infiltration, and finally add the leaf powder and lubricant to form a homogeneous mixture. Finally, use a twin-screw extruder to control the temperature in different zones, strengthen the fiber combination through shear force, and after discharging from the die, shape it in a water tank, eliminate stress by infrared heating, and naturally cool it down to get the final composite material product.
[0071] In step six, the three temperature control zones are the feeding zone, the melting zone and the homogenization zone. The feeding zone temperature is set to 120 degrees Celsius to ensure stable material delivery. The melting zone temperature gradient is set to 160-170 degrees Celsius to melt the plastic in stages and achieve fiber dispersion. The homogenization zone temperature is controlled at 190 degrees Celsius to ensure that the melt is fully plasticized and not degraded.
[0072] The low temperature of 140 degrees Celsius in the feeding zone ensures stable material delivery, avoiding premature melting that can cause blockage or energy waste. The temperature gradient of 160-170 degrees Celsius in the melting zone softens the plastic in stages and promotes uniform dispersion of the fibers, reducing thermal stress concentration and fiber agglomeration. Precise temperature control at 175 degrees Celsius in the homogenization zone allows the melt to fully plasticize to enhance the interfacial bonding strength, while avoiding material degradation caused by high temperatures, ensuring the mechanical properties and chemical stability of the finished product, and achieving a balance between efficient processing and product quality.
[0073] In step five, during the mixing process, circulating heat conduction oil is circulated in the mixing machine jacket to control the material temperature below the plastic melting point.
[0074] Precise temperature control by circulating heat conduction oil can maintain the material in a solid state, avoiding clumping caused by premature melting of plastic particles due to excessive temperature, ensuring that the fibers and plastic particles are fully dispersed and mixed in the unmelted stage, reducing agglomeration or uneven mixing caused by local melting.
[0075] In step four, after the bark, shell fibers and wood short fibers are treated with alkali, a silane coupling agent is prepared into an ethanol solution with a concentration of 1% to 2%, and is uniformly sprayed by a spraying device. The silane coupling agent is selected from one of KH550, KH570 or titanium ester NDZ-201. KH550 is used for surface treatment of bark fibers, KH570 is used for shell fiber treatment, and titanium ester coupling agent is used for wood short fiber modification. Then, drying treatment is carried out at a temperature of sixty degrees Celsius.
[0076] Wherein, before the third stage in step five, the surface modified nano zinc oxide is pre-mixed with the leaf powder by dry method, and then the pre-mixed nano zinc oxide and leaf powder mixture is added into the high-speed mixer together with the stearic acid lubricant.
[0077] The leaf powder has micro-nano pore structure after ultrafine grinding, and can be used as a carrier to load nano zinc oxide particles, thereby reducing the agglomeration of nano particles, and finally achieving the purpose of improving the antibacterial rate of the composite material through the synergy of the functionality of the leaf powder and the nano zinc oxide.
[0078] Wherein, before the first stage in step five, the hydrophobically modified lignin and the bio-based plastic particles are added into the high-speed mixer together with the maleic anhydride grafted polyethylene compatibilizer. When the plastic particles begin to melt, the lignin derivative gradually disperses into the plastic matrix under the action of shear force, forming a uniform blend system.
[0079] By adding lignin, the outdoor service life of the eucommia wood plastic composite material is prolonged, and the overall weather resistance of the material is improved.
[0080] Wherein, the segmented drying of the shells and leaves in step two is divided into an initial stage and a main stage. The initial stage is set to a temperature of 60 degrees Celsius and dried for 2 hours to remove surface free water. The main drying stage is heated to 80 degrees Celsius and dried for 4 to 6 hours, during which the material is turned every 30 minutes to ensure uniform heating.
[0081] The initial stage removes surface free water to avoid decomposition of heat-sensitive substances or leaf curling caused by high-temperature sudden heating. The main stage is heated and combined with timed turning of the material to strengthen the efficient evaporation of internal bound water and eliminate dry dead angles caused by uneven local heating, which not only balances drying efficiency and energy consumption, but also reduces the risk of carbonization through gradient heating and dynamic turning.
[0082] Wherein, the segmented drying of the bark and wood fiber bundles in step two is divided into an initial stage and a temperature rising stage. The initial stage is dried at a temperature of 60 degrees Celsius for 3 hours, and the temperature rising stage is heated to 80 degrees Celsius for 6 hours.
[0083] The segmented drying of the bark and wood fiber bundles removes surface and shallow water through the initial stage to avoid fiber shrinkage deformation or internal stress concentration caused by high-temperature sudden rise. The temperature rising stage gradually evaporates deep bound water, which not only reduces fiber thermal cracking and gum loss through gradient temperature control, but also ensures the integrity of the fiber structure and the uniformity of the moisture content through long-term medium-temperature drying.
[0084] Wherein, the water temperature of the vacuum shaping tank in step six is controlled at 15 to 20 degrees Celsius to avoid material deformation caused by sudden cooling.
[0085] By controlling the water tank temperature, the deformation and internal stress concentration caused by the quenching shrinkage of the material can be inhibited, the molten composite material is uniformly cooled by low-temperature slow cooling, the uneven crystallization, micro-cracks or surface warping caused by excessive temperature difference are avoided, and the size accuracy of the profile and the compactness of the cross-section structure are ensured.
[0086] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another, without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.
[0087] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, alternatives, and variations can be made in the embodiments without departing from the spirit and scope of the present application as defined by the appended claims and their equivalents.
Claims
1. A method for processing and manufacturing natural Eucommia wood-plastic composite materials, characterized in that: The specific steps are as follows: Step 1: Raw material pretreatment Bark processing: The rough outer skin of the collected Eucommia bark is manually peeled off, and the inner phloem part rich in Eucommia gum is retained. The bark is repeatedly washed with a high-pressure water gun to remove mud, insect eggs and residual impurities attached to the surface. The washed bark needs to be drained and spread in a ventilated place for preliminary drying; Shell processing: The Eucommia ulmoides shells are crushed by mechanical crushing equipment to separate the hard shell and the inner membrane. The crushed shells are graded and screened using a vibrating screen to remove debris and dust with a particle size of less than 1 mm. The hard shells are used as raw materials after screening; Leaf processing: manually remove the yellow and rotten leaves from the leaves, retain the intact green leaves, put the leaves into the rinsing tank, soak them in clean water for 2 hours and stir to remove soluble tannins. After rinsing, transfer them to the centrifuge for dehydration to reduce the subsequent drying energy consumption; Eucommia wood processing: Remove the aging bark containing impurities on the surface of the Eucommia wood, retain the clean wood inside, use a planer to remove the remaining bark and rotten parts on the surface, place the wood segments in a steam tank, and steam with saturated steam (0.3MPa, 120℃) for 1.5 hours to reduce the lignin content and soften the fibers. Use a fiber separator to break down the softened wood into wood fiber bundles with a diameter of 0.5-2mm, and remove unseparated wood fragments; Residue treatment: The residue after extracting Eucommia gum is separated into the gum film and the fiber matrix by an eddy current separator, and the residual fiber matrix is crushed to 80-100 mesh for the second time to obtain regenerated fiber powder for use; Step 2: Drying The processed fruit shells and leaves are spread flat on the tray and placed in the electric hot air drying oven for segmented drying; The processed bark and wood fiber bundles are spread flat on the tray and placed in an electric heated air drying oven for segmented drying; Use a rapid moisture meter to test until the moisture content of all raw materials is less than 3%; Step 3: Crushing and Classification The bark and husk are coarsely crushed by a hammer mill, first crushed into 20 mesh coarse powder, and then separated into 40 to 80 mesh fiber bundles by an air flow separator, and the unbroken coarse particles are removed and returned to the crushing machine; Use an ultrafine grinder under nitrogen protection to finely grind the leaves, control the feed rate and the gap between the blades, and finally obtain 100 to 150 mesh ultrafine powder, which is sealed and stored to avoid moisture absorption; The wood fiber bundles are further refined by a disc refiner, and the spacing between the grinding discs is adjusted to 0.1-0.3 mm to obtain wood short fibers with a length of 3-5 mm and a diameter of 0.1-0.5 mm; Step 4: Fiber activation Alkali treatment enhancement: Prepare a 5% sodium hydroxide solution and immerse the bark, husk fiber and wood short fiber in the solution at a solid-liquid ratio of 1:
10. Maintain a constant temperature of 40 degrees Celsius and soak for 2 hours. After treatment, neutralize with dilute hydrochloric acid to a pH of 7.0, rinse with deionized water until the conductivity is less than 50μS / cm, and dry for later use. Microwave-induced colloid exudation: bark fiber and wood short fiber are mixed in a 1:1 ratio and spread flat in a microwave treatment chamber. The microwave power is set to 500 watts and the irradiation time is 2 minutes. The high-frequency electromagnetic waves cause the molecular chains of the eucommia gum inside the fiber to break and migrate, forming a uniform film on the fiber surface. After treatment, the fiber is immediately cooled to room temperature with cold air to prevent colloid oxidation. Functional synergistic modification: Ultrafine leaf powder is mixed with 1%-3% composite filler in a mixer for 30 minutes. The composite filler is made of silicon dioxide, calcium carbonate, and titanium dioxide in a ratio of 1:0.5:0.
3. The active ingredients in the leaves are loaded by the adsorption effect of nanoparticles to improve the thermal stability during subsequent processing. Step 5: Blending modification process Use a high-speed mixer to premix the raw materials. Set the mixer speed to 1200 revolutions per minute. The mixing process is divided into three stages: Phase 1: Bio-based plastic particles, including polyethylene, polypropylene, polyvinyl chloride, and polycarbonate, are placed in a mixer with the corresponding compatibilizer. The compatibilizer uniformly coats the molten plastic particles. The mixing time is 3 to 5 minutes. The second stage: pre-treated Eucommia bark fiber, regenerated fiber powder, husk fiber and wood staple fiber are added to the mixer in batches. A gradient mixing strategy is adopted, first mixing at low speed for 1 minute to initially disperse the fibers, then gradually increasing to full speed and mixing for 5 to 8 minutes to ensure that the fibers are fully infiltrated with the molten plastic. Stage 3: Finally, add the ultrafinely ground leaf powder and stearic acid lubricant and continue mixing for 2 to 3 minutes until all ingredients form a homogeneous mixture; Step 6: Extrusion A co-rotating twin-screw extruder is used, with three temperature-controlled zones along the barrel: feeding, melting, and homogenizing. The screw speed is adjusted to 200 to 250 revolutions per minute, promoting fiber-plastic interface bonding through high shear. The die pressure is maintained at 4 to 6 MPa, and a porous plate is used to filter melt impurities. The material immediately enters a vacuum setting tank after exiting the die. The extruded profile was placed in an infrared heating furnace and kept at 80 degrees Celsius for 30 minutes to slowly release the residual stress inside the material, and then naturally cooled to room temperature.
2. The method for processing and manufacturing a natural Eucommia ulmoides wood-plastic composite material according to claim 1, characterized in that: The three temperature control zones described in step six are the feeding zone, the melting zone, and the homogenizing zone. The temperature of the feeding zone is set to 120 degrees Celsius to ensure smooth material transportation; the temperature gradient of the melting zone is set to 160 to 170 degrees Celsius to melt the plastic in sections and achieve fiber dispersion; the temperature of the homogenizing zone is controlled at 190 degrees Celsius to ensure that the melt is fully plasticized and not degraded.
3. The method for processing and manufacturing a natural Eucommia ulmoides wood-plastic composite material according to claim 1, characterized in that: During the mixing process described in step 5, circulating heat transfer oil is introduced into the jacket of the mixer to control the material temperature below the melting point of the plastic.
4. The method for processing and manufacturing a natural Eucommia ulmoides wood-plastic composite material according to claim 1, characterized in that: After the bark, husk fiber and wood short fiber are strengthened by alkali treatment in step 4, a silane coupling agent is prepared into an ethanol solution with a concentration of 1% to 2%, and evenly sprayed through a spray device. The silane coupling agent is selected from one of KH550, KH570 or titanate NDZ-201, wherein KH550 is used for bark fiber surface treatment, KH570 is used for husk fiber treatment, and titanate coupling agent is used for wood short fiber modification. Subsequently, the mixture is dried at a temperature of 60 degrees Celsius.
5. The method for processing and manufacturing a natural Eucommia ulmoides wood-plastic composite material according to claim 1, characterized in that: Before the third stage in step 5, the surface-modified nano zinc oxide and leaf powder are pre-mixed by dry method, and then the pre-mixed nano zinc oxide and leaf powder mixture is added into a high-speed mixer together with stearic acid lubricant.
6. The method for processing and manufacturing a natural Eucommia ulmoides wood-plastic composite material according to claim 1, characterized in that: Before the first stage in step five, the hydrophobically modified lignin, bio-based plastic particles and maleic anhydride grafted polyethylene compatibilizer are added to a high-speed mixer. When the plastic particles begin to melt, the lignin derivative is gradually dispersed into the plastic matrix under the action of shear force to form a uniform blending system.
7. The method for processing and manufacturing a natural Eucommia ulmoides wood-plastic composite material according to claim 1, characterized in that: The segmented drying of the fruit shells and leaves in step 2 is divided into an initial stage and a main stage. The temperature in the initial stage is set at 60 degrees Celsius and dried for 2 hours to remove surface free water; the temperature in the main drying stage is raised to 80 degrees Celsius and the drying is continued for 4 to 6 hours. During this period, the material is turned over every 30 minutes to ensure uniform heating.
8. The method for processing and manufacturing a natural Eucommia ulmoides wood-plastic composite material according to claim 1, characterized in that: The segmented drying of the bark and wood fiber bundles in step 2 is divided into an initial stage and a heating stage. The initial stage is drying at 60° C. for 3 hours, and the heating stage is drying at 80° C. for 6 hours.
9. The method for processing and manufacturing a natural Eucommia ulmoides wood-plastic composite material according to claim 1, characterized in that: The water temperature of the vacuum setting tank described in step 6 is controlled at 15 to 20 degrees Celsius to avoid sudden cooling and deformation of the material.