Plant fiber molded composite material and method of manufacturing, integrated system

Abstract

The present application belongs to the technical field of composite materials, and particularly relates to a plant fiber molded composite material, a preparation method thereof and an integrated system. The present application utilizes softwood to perform softwood pitch leaching-plant fiber modification-softwood pitch plastic extrusion integrated process, directly performs surface modification on the plant fiber by using the softwood pitch leaching liquor, reduces the surface polarity of the plant fiber and improves the performance of the composite material. The present application reduces the modification cost in the forming process of the plant fiber molded composite material while utilizing waste, and further crosslinks and extrudes to form softwood pitch plastic after concentrating the softwood pitch leaching liquor to prepare softwood pitch, so as to coat, strengthen and protect the plant fiber molded core material, prepare high-strength and high-stability full-green plant molded material, and provide technical support for the development of the softwood and plant fiber industry.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of composite materials, and particularly relates to a plant fiber molded composite material and a preparation method and an integrated system thereof. BACKGROUND

[0002] Plant fibers mainly include high molecular components such as cellulose, lignin, hemicellulose, pectin and wax, and have the characteristics of degradability, recyclability and renewability. Plant fiber molded composite materials prepared from plant fibers have attracted much attention. However, due to the fluffy and disordered plant fibers, poor dispersibility and polarity, the plant fiber molded composite materials have defects such as large brittleness, easy deformation and difficult processing, because of the uneven bubbles and fiber aggregation. At present, the above problems are mainly overcome by modifying the plant fibers. However, the existing modification method is complicated in steps and operation, seriously restricts the modification efficiency of the plant fibers, and increases the production cost of the plant fiber molded composite materials. SUMMARY

[0003] Therefore, the application provides a plant fiber molded composite material, a preparation method and an integrated system thereof. The integrated system can prepare the plant fiber molded composite material with high strength and high stability from softwood and plant fibers, the preparation process is simple and easy to operate, the integration is realized, and the production cost is reduced.

[0004] In order to solve the above technical problems, the application provides an integrated system for preparing a plant fiber molded composite material, which comprises an extraction unit, a modification unit, a crosslinking unit and a compounding unit.

[0005] The extraction unit comprises an extractant container 1, a softwood container 2, an extraction device 3 connected with the outlets of the extractant container 1 and the softwood container 2 respectively, an extraction liquid container 5 connected with the extraction liquid outlet 3-1 arranged below the side wall of the extraction device 3, and a waste container 6 connected with the waste outlet 3-2 arranged at the bottom of the extraction device 3.

[0006] The modification unit comprises a plant fiber container 4, a modification device 7-1 connected with the outlet of the plant fiber container 4 and the outlet of the extraction liquid container 5 respectively, a first extractant recovery container 8-1 connected with a first gas outlet 7-1-1 arranged at the top of the modification device 7-1, a modified fiber container 9 connected with a modified fiber outlet 7-1-2 arranged at the bottom of the modification device 7-1, and a modified fiber board preparation device 15 connected with the outlet of the modified fiber container 9; a distillation device 7-2 connected with the outlet of the extraction liquid container 5, a second extractant recovery container 8-2 connected with a second gas outlet 7-2-1 arranged at the top of the distillation device 7-2, and a softwood pitch container 10 connected with a softwood pitch outlet 7-2-2 arranged at the bottom of the distillation device 7-2;

[0007] The crosslinking unit comprises a crosslinking agent container 18, a crosslinking device 19 connected with the outlet of the crosslinking agent container 18 and the outlet of the softwood pitch container 10 respectively, and a softwood pitch forming device 13 connected with the outlet arranged at the bottom of the crosslinking device 19.

[0008] The composite unit comprises a hot-press forming device 16 connected with the softwood pitch forming device 13 and the modified fiber board preparation device 15.

[0009] Preferably, a central control system 12 is further included, which is connected with the extraction unit, the modification unit, the crosslinking unit and the composite unit through signals.

[0010] Preferably, a heating structure and a solid-liquid separation structure are arranged in the extraction device 3.

[0011] Preferably, a heating structure is arranged in the modification device 7-1; and a heating structure is arranged in the distillation device 7-2.

[0012] The modification device 7-1 and the distillation device 7-2 are connected in parallel.

[0013] Preferably, a heating structure is arranged in the crosslinking device 19.

[0014] The application further provides a method for preparing a plant fiber molded composite material by using the integrated system.

[0015] The extractant and the softwood are placed in the extraction device 3 to perform extraction, so as to obtain extraction liquid;

[0016] The extraction liquid and the plant fiber are mixed in the modification device 7-1 to perform modification, so as to obtain modified fiber;

[0017] The extraction liquid is transferred to the distillation device 7-2 to perform distillation, so as to obtain softwood pitch;

[0018] The cork resin and the cross-linking agent are mixed in the cross-linking device 19 to perform a cross-linking reaction and then formed to obtain a cork resin plastic film;

[0019] The modified fiber is prepared into a modified fiber board by using a modified fiber board preparation device 15.

[0020] After the softwood resin plastic film is placed on the upper surface and the lower surface of the modified fiber board, the modified fiber board is hot-pressed in a hot-pressing forming device 16 to obtain a plant fiber molded composite material.

[0021] Preferably, the extraction agent includes a mixture of aliphatic hydrocarbons, alcohols, esters, petroleum ether and ethanol or acetone.

[0022] The temperature of the extraction is 20-80℃, the time is 2-6h, and the pressure is 0.1-0.5MPa.

[0023] Preferably, the cross-linking agent includes a multifunctional epoxy cross-linking agent, an isocyanate, a thermoplastic elastomer or an organic peroxide cross-linking agent.

[0024] The mass ratio of the cork resin and the cross-linking agent is 1:1-100.

[0025] The temperature of the cross-linking reaction is 20-200℃, and the time is 0.5-4h.

[0026] Preferably, the temperature of the hot-pressing is 80-180℃, the pressure is 0.1-5MPa, and the time is 5-30min.

[0027] The application further provides a plant fiber molded composite material prepared by the method.

[0028] The modified fiber in the modified fiber board is a plant fiber and a softwood resin coated on the surface of the plant fiber.

[0029] The application provides an integrated system for preparing plant fiber molded composite materials, comprising an extraction unit, a modification unit, a crosslinking unit and a composite unit; the extraction unit comprises an extractant container 1, a cork container 2, an extraction device 3 connected with the outlet of the extractant container 1 and the outlet of the cork container 2 respectively, an extraction liquid container 5 connected with the extraction liquid outlet 3-1 arranged below the side wall of the extraction device 3, and a waste container 6 connected with the waste outlet 3-2 arranged at the bottom of the extraction device 3; the modification unit comprises a plant fiber container 4, a modification device 7-1 connected with the outlet of the plant fiber container 4 and the outlet of the extraction liquid container 5 respectively, a first extractant recovery container 8-1 connected with the first gas outlet 7-1-1 arranged at the top of the modification device 7-1, a modified fiber container 9 connected with the modified fiber outlet 7-1-2 arranged at the bottom of the modification device 7-1, and a modified fiber board preparation device 15 connected with the outlet of the modified fiber container 9; a distillation device 7-2 connected with the outlet of the extraction liquid container 5, a second extractant recovery container 8-2 connected with the second gas outlet 7-2-1 arranged at the top of the distillation device 7-2, and a cork pitch container 10 connected with the cork pitch outlet 7-2-2 arranged at the bottom of the distillation device 7-2; the crosslinking unit comprises a crosslinking agent container 18, a crosslinking device 19 connected with the outlet of the crosslinking agent container 18 and the outlet of the cork pitch container 10 respectively, and a cork pitch forming device 13 connected with the outlet arranged at the bottom of the crosslinking device 19; and a hot-pressing forming device 16 connected with the cork pitch forming device 13 and the modified fiber board preparation device 15. The application uses cork and plant fiber as raw materials, and uses the above integrated system to prepare plant fiber molded composite materials with high strength and high stability, and the preparation process is simple and easy to operate, realizes integration, and reduces the production cost.

[0030] The application uses cork to prepare plant fiber molded composite materials by a cork pitch extraction-plant fiber modification-cork pitch plastic extrusion integrated process, directly modifies the surface of plant fiber by using cork pitch extraction liquid, reduces the surface polarity of plant fiber and improves the performance of the composite material; the application reduces the modification cost in the molding process of plant fiber molded composite materials while utilizing waste; after the cork pitch extraction liquid is concentrated to prepare cork pitch, the cork pitch is further crosslinked and extruded to form a cork pitch plastic, which is used for coating, enhancing and protecting the plant fiber molded core material, and high-strength and high-stability all-green plant molded materials are prepared, thereby providing technical support for the development of cork and plant fiber industries. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1Structure diagram of the integrated system used in Example 1, wherein 1 is the extractant container, 2 is the cork container, 3 is the extraction device, 3-1 is the extraction liquid outlet, 3-2 is the waste outlet, 4 is the plant fiber container, 5 is the extraction liquid container, 6 is the waste container, 7-1 is the modification device, 7-1-1 is the first gas outlet, 7-1-2 is the modified fiber outlet, 7-2 is the distillation device, 7-2-1 is the second gas outlet, 7-2-2 is the cork pitch outlet, 8-1 is the first extractant recovery container, 8-1-1 is the first condenser, 8-2 is the second extractant recovery container, 8-2-1 is the second condenser, 9 is the modified fiber container, 10 is the cork pitch container, 11-1 is the second control valve, 11-2 is the first control valve, 11-3 is the third control valve, 11-4 is the fourth control valve, 11-5 is the fifth control valve, 11-6 is the sixth control valve, 11-7 is the seventh control valve, 11-8 is the eighth control valve, 11-9 is the ninth control valve, 11-10 is the tenth control valve, 12 is the central control system, 13 is the cork pitch molding device, 18 is the crosslinking agent container, 19 is the crosslinking device, 15 is the modified fiber board preparation device, 16 is the hot-pressing molding device.

[0032] Figure 2 Structure diagram of the plant fiber molded composite material, wherein 14 is the cork pitch plastic film, and 17 is the modified fiber board. DETAILED DESCRIPTION

[0033] The present application provides an integrated system for preparing a plant fiber molded composite material, comprising an extraction unit, a modification unit, a crosslinking unit and a composite unit.

[0034] In the present application, the leaching unit comprises an extractant container 1, a cork container 2, a leaching device 3 with an inlet connected to the outlet of the extractant container 1 and the outlet of the cork container 2 respectively, a leaching liquid container 5 with an inlet connected to the leaching liquid outlet 3-1 arranged below the side wall of the leaching device 3, and a waste container 6 with an inlet connected to the waste outlet 3-2 arranged at the bottom of the leaching device 3. As an embodiment of the present application, the outlet of the extractant container 1 is provided with a first control valve 11-2, and the outlet of the cork container 2 is provided with a second control valve 11-1. The present application adjusts the ratio of the extractant and the cork entering the leaching device 3 through the first control valve 11-2 and the second control valve 11-1. As an embodiment of the present application, the leaching device 3 is provided with a heating structure and a solid-liquid separation structure inside. The present application has no special requirements for the heating structure and the solid-liquid separation structure, which can be realized by conventional methods in the art. The present application provides temperature for leaching through the heating structure, and separates the leaching liquid and the cork residue through the solid-liquid separation structure. The present application stores the leaching liquid in the leaching liquid container 5, and stores the cork residue in the waste container 6. As an embodiment of the present application, the leaching liquid outlet 3-1 is provided with a third control valve 11-3, and the waste outlet 3-2 is provided with a fourth control valve 11-4. The present application controls the flow of the leaching liquid by adjusting the third control valve 11-3, and controls the removal of the cork residue by adjusting the fourth control valve 11-4.

[0035] In the present application, the modification unit comprises a plant fiber container 4, a modification device 7-1 connected with the outlet of the plant fiber container 4 and the outlet of the extraction liquid container 5 respectively, a first extractant recovery container 8-1 connected with a first gas outlet 7-1-1 arranged at the top of the modification device 7-1, a modified fiber container 9 connected with a modified fiber outlet 7-1-2 arranged at the bottom of the modification device 7-1, and a modified fiber board preparation device 15 connected with the outlet of the modified fiber container 9; a distillation device 7-2 connected with the outlet of the extraction liquid container 5, a second extractant recovery container 8-2 connected with a second gas outlet 7-2-1 arranged at the top of the distillation device 7-2, and a softwood pitch container 10 connected with a softwood pitch outlet 7-2-2 arranged at the bottom of the distillation device 7-2. As an embodiment of the present application, a fifth control valve 11-5 is arranged at the outlet of the plant fiber container 4, and the present application controls the amount of plant fiber entering the modification device by regulating the fifth control valve 11-5. As an embodiment of the present application, a heating structure and a stirring structure are arranged in the modification device 7-1, and the present application has no special requirements for the heating structure and the stirring structure, which can be adopted in a conventional manner in the art. The present application uses the heating structure to provide the required temperature for the modification device 7-1. As an embodiment of the present application, a sixth control valve 11-6 is arranged at the inlet of the modification device 7-1, and the present application controls the amount of extraction liquid entering the modification device 7-1 by regulating the sixth control valve 11-6. As an embodiment of the present application, a heating structure is arranged in the distillation device 7-2, and the present application has no special requirements for the heating structure, which can be adopted in a conventional manner in the art. The present application uses the heating structure to provide the required temperature for the distillation device 7-2. As an embodiment of the present application, a seventh control valve 11-7 is arranged at the inlet of the distillation device 7-2, and the present application controls the amount of extraction liquid entering the distillation device 7-2 by regulating the seventh control valve 11-7. As an embodiment of the present application, the modification device 7-1 is a rotary evaporator, and the distillation device 7-2 is a rotary evaporator. As an embodiment of the present application, the modification device 7-1 and the distillation device 7-2 are connected in parallel. As an embodiment of the present application, a first condenser 8-1-1 is arranged at the inlet of the first extractant recovery container 8-1, and a second condenser 8-2-1 is arranged at the inlet of the second extractant recovery container 8-2. The present application recovers the gaseous extractant by the first condenser 8-1-1 and the second condenser 8-2-1.

[0036] In the present application, the cross-linking unit comprises a cross-linking agent container 18, a cross-linking device 19 with an inlet connected to the outlet of the cross-linking agent container 18 and the outlet of the suberin container 10, and a suberin forming device 13 connected to the outlet of the bottom of the cross-linking device 19. As an embodiment of the present application, the outlet of the cross-linking agent container 18 is provided with an eighth control valve 11-8, and the present application controls the amount of cross-linking agent entering the cross-linking device 19 by regulating the eighth control valve 11-8. As an embodiment of the present application, the outlet of the suberin container 10 is provided with a ninth control valve 11-9, and the present application controls the amount of suberin entering the cross-linking device 19 by regulating the ninth control valve 11-9. As an embodiment of the present application, the cross-linking device 19 is provided with a heating structure and a stirring structure inside. The present application has no special requirements for the heating structure and the stirring structure, and can be used in a conventional manner in the art. The present application uses the heating structure to provide the required temperature for the cross-linking device 19; the present application uses the stirring structure to mix the materials uniformly to facilitate the reaction to proceed fully. As an embodiment of the present application, the outlet of the cross-linking device 19 is provided with a tenth control valve 11-10.

[0037] As an embodiment of the present application, the suberin forming device 13 is an extruder.

[0038] In the present application, the composite unit comprises a hot-press forming device 16 connected to the suberin forming device 13 and the modified fiber plate material preparation device 15. The present application has no special limitation on the modified fiber plate material preparation device 15 and the hot-press forming device 16, and can use conventional equipment in the art.

[0039] As an embodiment of the present application, the integrated system further comprises a central control system 12 connected to the extraction unit, the modification unit, the cross-linking unit and the composite unit by signals. The present application can control the equipment in the integrated system to realize integrated operation through the central control system 12. The present application transmits the amount of material transportation between each unit to the central control system through electrical signals through each control valve, in order to control the amount of material in the same stage and the next stage. The transmission of signals enables each system to complete in an orderly manner, ensuring sufficient supply and complete reaction.

[0040] The present application provides a method for preparing plant fiber molded composites using the integrated system described in the above technical solution, comprising the following steps:

[0041] The extractant and the suberin are placed in the extraction device 3 for extraction to obtain an extraction solution;

[0042] The extraction solution and the plant fiber are mixed in the modification device 7-1 for modification to obtain modified fiber;

[0043] The extraction solution is transferred to the distillation device 7-2 for distillation to obtain suberin;

[0044] The cork resin and the cross-linking agent are mixed in the cross-linking device 19 to perform a cross-linking reaction and then formed to obtain a cork resin plastic film;

[0045] The modified fiber is prepared into a modified fiber board by using a modified fiber board preparation device 15;

[0046] After the softwood resin plastic film is placed on the upper and lower surfaces of the modified fiber board, the modified fiber board is hot-pressed in a hot-pressing device 16 to obtain a plant fiber molded composite material.

[0047] In the present application, the extraction agent preferably includes a mixture of aliphatic hydrocarbons, alcohols, esters, petroleum ether and ethanol or acetone, and more preferably acetone. In the present application, the aliphatic hydrocarbons preferably include n-hexane, petroleum ether or toluene, and more preferably toluene. In the present application, the alcohols preferably include ethanol, propanol or methanol, and more preferably ethanol. In the present application, the esters are preferably ethyl acetate.

[0048] In the present application, the softwood is preferably softwood processing waste, and the softwood processing waste is preferably from a softwood processing factory. In the present application, the softwood is preferably crushed before extraction; the average particle size of the crushed softwood is preferably 30-800 mesh, and more preferably 100-700 mesh. The present application does not have special requirements for the crushing method, as long as the desired particle size can be achieved. The present application crushes the softwood to facilitate the full contact between the softwood and the extraction agent, thereby improving the extraction efficiency.

[0049] In the present application, the mass ratio of the softwood to the extraction agent is preferably 1:1-100, and more preferably 1:3-50.

[0050] In the present application, the extraction method preferably includes direct distillation, organic solvent soaking, ultrasonic dissolution, cork resin microwave method or high-pressure extraction, and more preferably direct distillation. In the present application, the temperature used in the direct distillation method is preferably 50-100℃, more preferably 58-90℃, and further preferably 60-80℃; the time used in the direct distillation method is preferably 2-4h, and more preferably 3h. In the present application, the power of the ultrasonic wave used in the ultrasonic dissolution method is preferably 40-2000W, and more preferably 100-1000W; the time used in the ultrasonic dissolution method is preferably 10-50min, and more preferably 20-40min. In the present application, the power of the microwave used in the cork resin microwave method is preferably 40-2000W, and more preferably 100-1000W; the time used in the cork resin microwave method is preferably 10-50min, and more preferably 20-40min.

[0051] In the present application, the temperature of the leaching is preferably 20-80℃; the time of the leaching is preferably 0.1-6h, more preferably 3-5h; the pressure of the leaching is preferably 0.1-0.5MPa, more preferably 0.2-0.5MPa. The present application preferably limits the specific leaching temperature according to the type of leaching agent, specifically: when the leaching agent is aliphatic hydrocarbon, the leaching temperature is preferably 20-60℃; when the leaching agent is alcohol or ester, the leaching temperature is preferably 60-80℃; when the leaching agent is a mixture of petroleum ether and ethanol, the leaching temperature is preferably 25-40℃; when the leaching agent is acetone, the leaching temperature is preferably 40-60℃.

[0052] In the present application, the leaching is preferably followed by solid-liquid separation of the leached system to obtain a leaching solution. In the present application, the solid-liquid separation is preferably by centrifugation or filtration, more preferably by filtration; the filtration is preferably suction filtration.

[0053] After obtaining the leaching solution, the present application mixes the leaching solution and the plant fiber in the modification device 7-1 to modify, obtaining modified fiber. In the present application, the plant fiber preferably includes wood fiber, hemp fiber, palm fiber, bamboo fiber or crop fiber, more preferably bamboo fiber. In the present application, the mass ratio of the plant fiber to the leaching solution is preferably 1:1-100, more preferably 1:4-20. In the present application, the mixing is preferably carried out under stirring, and the stirring speed is preferably 10-1000r / min, more preferably 50-200r / min. In the present application, the modification temperature is preferably higher than the melting point of the extractant; the modification time is preferably 0.1-6h, more preferably 0.5-2h. In the present application, when the extractant is petroleum ether, the modification temperature is preferably 40-60℃; when the extractant is a mixed solution of petroleum ether and ethanol, the modification temperature is preferably 50-70℃; when the extractant is n-hexane, the modification temperature is preferably 60-80℃; when the extractant is ethanol, the modification temperature is preferably 78℃; when the extractant is propanol, the modification temperature is preferably 82℃; when the extractant is methanol, the modification temperature is preferably 64-65℃; when the extractant is ethyl acetate, the modification temperature is preferably 77-78℃; when the extractant is toluene, the modification temperature is preferably 61-62℃; and when the extractant is acetone, the modification temperature is preferably 56.5-58℃, more preferably 58℃. The present application preferably provides the required modification temperature by water bath.

[0054] After modification, the present application coats softwood pitch on the surface of the plant fiber to reduce the surface tension of the plant fiber. In the modification process, the present application evaporates and removes the leaching agent in the leaching solution.

[0055] Due to the polar groups on the surface of the plant fibers, the plant fibers have poor dispersibility, and phenomena such as uneven bubbles and fiber aggregation are easily caused; softwood pitch is a natural terpene polymer material, has good biocompatibility, fluidity, heat resistance and chemical resistance, helps to shield the polar groups, and makes the mixing and dispersion of the plant fibers more uniform; the natural softwood pitch is introduced as a modifier and dispersant in the application, is wrapped on the surface of the plant fibers, and improves the physical and mechanical stability of the plant fibers.

[0056] After the leaching solution is obtained, the leaching solution is transferred to a distillation device 7-2 to distill softwood pitch. In the application, the distillation temperature is determined according to the selected extractant, and the distillation temperature is preferably above the melting point of the extractant, specifically: when the extractant is petroleum ether, the distillation temperature is preferably 40-60 DEG C; when the extractant is a mixed solution of petroleum ether and ethanol, the distillation temperature is preferably 50-70 DEG C; when the extractant is n-hexane, the distillation temperature is preferably 60-80 DEG C; when the extractant is ethanol, the distillation temperature is preferably 78-80 DEG C; when the extractant is propanol, the distillation temperature is preferably 82 DEG C; when the extractant is methanol, the distillation temperature is preferably 64-65 DEG C; when the extractant is ethyl acetate, the distillation temperature is preferably 77-78 DEG C; when the extractant is toluene, the distillation temperature is preferably 61-62 DEG C, when the extractant is acetone, the distillation temperature is preferably 56.5-58 DEG C, and more preferably 58 DEG C. The extractant in the leaching solution is removed by distillation in the application, and the purity of the softwood pitch is improved.

[0057] In the application, the natural softwood pitch is used as a modifier and dispersant of the plant fiber molded core material, and the crosslinked softwood pitch plastic prepared by the natural softwood pitch is used as a protective surface material, which can improve the physical and mechanical stability of the plant fiber molded composite material and prolong the service life of the composite material during transportation and use.

[0058] After obtaining the cork pitch, the present application mixes the cork pitch and a cross-linking agent in the cross-linking device 19 to perform a cross-linking reaction and then forms a cork pitch plastic film. In the present application, the cross-linking agent preferably includes a multifunctional epoxy cross-linking agent, an isocyanate, a thermoplastic elastomer or an organic peroxide cross-linking agent, and more preferably a multifunctional epoxy cross-linking agent. In the present application, the multifunctional epoxy cross-linking agent preferably includes Araldite AV 138M / HV 998, Epon 828 / 1001 or DEN 438, and more preferably Epon 828 / 1001. In the present application, the thermoplastic elastomer preferably includes Kraton G1652, SEBS 8502 or Santoprene 201-80. In the present application, the organic peroxide cross-linking agent preferably includes dimethyl peroxide (DMPO), bis(n-butyl) peroxide (BPO), benzoyl peroxide (BPO) or tert-butyl benzene peroxide (TBPB). In the present application, the isocyanate is preferably Loctite AA 3526, 3M DP810 or VHB 4910. In the present application, the mass ratio of the cork pitch and the cross-linking agent is preferably 1:1-100, and more preferably 1:1-10.

[0059] In the present application, the temperature of the cross-linking reaction is preferably 20-200°C, and the time of the cross-linking reaction is preferably 0.5-4h, and more preferably 0.5-2h. The present application preferably limits the temperature of the cross-linking reaction according to the type of cross-linking agent, and specifically: when the cross-linking agent is a multifunctional epoxy cross-linking agent, the temperature of the cross-linking reaction is preferably 100-180°C, and more preferably 100-150°C; when the cross-linking agent is a thermoplastic elastomer, the temperature of the cross-linking reaction is preferably 120-180°C, and more preferably 130-170°C; when the cross-linking agent is an organic peroxide cross-linking agent, the temperature of the cross-linking reaction is preferably 140-200°C, and more preferably 150-180°C; and when the cross-linking agent is an isocyanate, the temperature of the cross-linking reaction is preferably 20-120°C, and more preferably 30-100°C. In the present application, the cross-linking reaction is preferably accompanied by stirring, and the stirring speed is preferably 100-200r / min, and more preferably 150-180r / min.

[0060] In the present application, the forming is preferably extrusion forming; the extrusion temperature of the extrusion forming is preferably 80-180°C, and more preferably 80-120°C; and the extrusion pressure of the extrusion forming is preferably 2-100MPa, and more preferably 10-40MPa. In the present application, the thickness of the cork pitch plastic film is preferably 0.1-4mm, and more preferably 0.2-3mm.

[0061] The present application enables the cork pitch and the high molecular cross-linking agent to fully react by limiting the reaction temperature, time and stirring homogeneity.

[0062] After obtaining the modified fiber, the present application uses the modified fiber board material preparation device 15 to prepare the modified fiber into a modified fiber board. The present application does not have special requirements for the way of preparing the modified fiber board, and the conventional way in the art can be used. In the embodiment of the present application, the modified fiber and the softwood are mixed to obtain a modified fiber board; the mass ratio of the modified fiber and the softwood is preferably 1-100:1, and more preferably 20-50:1.

[0063] After obtaining the softwood plastic film and the modified fiber board, the present application stacks the softwood plastic film on the upper and lower surfaces of the modified fiber board, and then hot-presses in the hot-pressing device 16 to obtain a plant fiber molded composite material. In the present application, the temperature of the hot-pressing is preferably 80-180°C, and more preferably 100-150°C; the pressure of the hot-pressing is preferably 0.1-5MPa, and more preferably 1-3MPa; the time of the hot-pressing is preferably 5-30min, and more preferably 5-15min.

[0064] Figure 1 The structure diagram of the integrated system used in Example 1 is shown in the figure, wherein 1 is an extractant container, 2 is a softwood container, 3 is an extraction device, 3-1 is an extraction liquid outlet, 3-2 is a waste outlet, 4 is a plant fiber container, 5 is an extraction liquid container, 6 is a waste container, 7-1 is a modification device, 7-1-1 is a first gas outlet, 7-1-2 is a modified fiber outlet, 7-2 is a distillation device, 7-2-1 is a second gas outlet, 7-2-2 is a softwood fat outlet, 8-1 is a first extractant recovery container, 8-1-1 is a first condenser, 8-2 is a second extractant recovery container, 8-2-1 is a second condenser, 9 is a modified fiber container, 10 is a softwood fat container, 11-1 is a second control valve, 11-2 is a first control valve, 11-3 is a third control valve, 11-4 is a fourth control valve, 11-5 is a fifth control valve, 11-6 is a sixth control valve, 11-7 is a seventh control valve, 11-8 is an eighth control valve, 11-9 is a ninth control valve, 11-10 is a tenth control valve, 12 is a central control system, 13 is a softwood fat molding device, 18 is a crosslinking agent container, 19 is a crosslinking device, 15 is a modified fiber board material preparation device, and 16 is a hot-pressing device.

[0065] The present application makes full use of cork processing waste, through cork resin extraction-plant fiber modification-cork resin plastic extrusion integrated process, the crude cork resin extract directly to the surface modification of plant fiber, reduces the surface polarity of plant fiber. Can in waste utilization, at the same time, reduce the modification cost in the process of plant fiber molding composite material forming process, at the same time, the excess cork resin extract is concentrated to prepare cork resin, and then further crosslinking extrusion molding, the cork resin plastic is prepared to coat the plant fiber molding core material to enhance and protect, and high strength, high stability all green plant molding material is prepared, the pollution of chemicals to the environment in the traditional modification method is avoided, and the present application has high environmental protection value.

[0066] The present application integrates cork resin and plant fiber to prepare molding material, the cork resin plastic prepared after crosslinking of cork resin is used as the protective layer of plant fiber based material, and high strength, high stability all green plant molding material is prepared. The problems of plant fiber, such as loose and disordered, poor dispersibility, easy to cause uneven bubbles, fiber aggregation and the like are effectively solved, and the quality and service life of plant fiber molding composite material are improved.

[0067] The present application utilizes cork processing waste to realize the dual benefits of waste utilization and cost reduction, and has wide application prospect, and provides technical support for the development of cork and plant fiber industry. Through waste utilization, the cork processing waste is recycled, resources are saved, and cost is reduced.

[0068] The present application also provides a plant fiber molding composite material prepared by the method.

[0069] The modified fiber in the modified fiber plate is plant fiber and cork resin coated on the surface of the plant fiber.

[0070] In the present application, the thickness of the plant fiber molding composite material is preferably 2-10mm, and more preferably 4-8mm.

[0071] Figure 2 The structure of the plant fiber molding composite material is shown in the figure, wherein 14 is cork resin plastic film, and 17 is modified fiber plate.

[0072] In order to further illustrate the present application, the technical solutions provided by the present application are described in detail in combination with examples, but they should not be understood as limiting the scope of protection of the present application.

[0073] Example 1

[0074] The softwood waste is crushed to obtain softwood particles with an average particle size of 300 mesh; the softwood particles and acetone are transferred into the extraction device 3 at a mass ratio of 1:3 (250 g of softwood particles, 750 g of acetone), and the direct distillation method is used for extraction under the conditions of a temperature of 58°C and a pressure of 0.1 MPa for 3 h, followed by suction filtration. The extraction liquid obtained by suction filtration is transferred into the extraction liquid container 5 through the control valve 11-3, and the softwood residue after suction filtration is transferred into the waste container 6 through the control valve 11-4;

[0075] The bamboo fiber raw material and the extraction liquid are transferred into the modification device 7-1 at a mass ratio of 1:4 (200 g of bamboo fiber, 800 g of extraction liquid) after sealing, and reflux modification is carried out under the conditions of a temperature of 58°C and a rotation speed of 150 r / min for 1 h. The excess acetone solvent is condensed by the condenser 8-1-1 and refluxed into the extractant recovery container 8-1, and the modified bamboo fiber is obtained.

[0076] The remaining extraction liquid is transferred into the distillation device 7-2 through the control valve 11-7 and sealed, and distillation is carried out at 58°C to obtain softwood pitch, which is stored in the softwood pitch container 10. The acetone gas is cooled by the condenser 8-2-1 and refluxed into the extractant recovery container 8-2;

[0077] The softwood pitch and the multifunctional epoxy crosslinking agent Epon 828 / 1001 are transferred into the crosslinking device 19 at a mass ratio of 1:1 (500 g of softwood pitch, 500 g of Epon 828 / 100) after sealing, and crosslinking reaction is carried out under the conditions of a temperature of 100°C and a rotation speed of 150 r / min for 1.5 h. The softwood pitch plastic film with a thickness of 0.2 mm is obtained by extrusion molding (extrusion temperature: 80°C, pressure: 10 MPa).

[0078] The modified bamboo fiber and the softwood particles are mixed at a mass ratio of 20:1 to prepare a modified bamboo fiber board with a thickness of 2 mm by uniform paving;

[0079] The softwood pitch plastic film, the modified bamboo fiber board, and the softwood pitch plastic film are stacked in this order and hot-pressed under the conditions of a pressure of 3 MPa and a temperature of 150°C for 15 min to obtain a plant fiber molded composite material with a thickness of 2.2 mm.

[0080] The bamboo fiber molded composite material prepared in Example 1 is detected according to GB / T 25975-2010 “Hanging board for external wall thermal insulation” and GB / T 11968-2006 “Method for testing the sound insulation performance of building walls”, and the detection results are listed in Table 1.

[0081] Table 1 Properties of the bamboo fiber molded composite material prepared in Example 1

[0082]

[0083]

[0084] From the data in Table 1, it can be seen that the bamboo fiber molded composite material prepared in Example 1 meets the strength, heat preservation and sound insulation requirements of bamboo fiber molded composite material as a wallboard.

[0085] Example 2

[0086] The softwood waste was crushed to obtain softwood particles with an average particle size of 300 mesh; the softwood particles and ethanol were transferred to the extraction device 3 in a ratio of 1:10 by mass (250g of softwood particles, 2500g of ethanol), treated by microwave method at a temperature of 78°C and a power of 50W for 20min, and then filtered, the filtered extraction liquid was transferred to the extraction liquid container 5 through the control valve 11-3, and the softwood residue after filtration was transferred to the waste container 6 through the control valve 11-4;

[0087] The bamboo fiber raw material and the extraction liquid were transferred to the modification device 7-1 in a ratio of 1:10 by mass (200g of hemp fiber, 2000g of extraction liquid) after sealing, and then refluxed at a temperature of 78°C and a rotation speed of 150r / min for 1h, the excess ethanol solvent was condensed by the condenser 8-1-1 and flowed back to the extractant recovery container 8-1, and the modified hemp fiber was obtained;

[0088] The remaining extraction liquid was transferred to the distillation device 7-2 through the control valve 11-7 and sealed, and then distilled at 80°C to obtain softwood pitch, which was stored in the softwood pitch container 10, and the ethanol gas was cooled by the condenser 8-2-1 and flowed back to the extractant recovery container 8-2;

[0089] The softwood pitch and isocyanate Loctite AA 3526 were transferred to the crosslinking device 19 in a ratio of 1:1.5 by mass (500g of softwood pitch, 750g of Loctite AA 3526) after sealing, and then crosslinked at a temperature of 90°C and a rotation speed of 150r / min for 1h, and then molded by an extruder (extrusion temperature was 100°C, pressure was 15MPa) to obtain a softwood pitch plastic film with a thickness of 1mm;

[0090] The modified hemp fiber and the softwood particles were mixed in a ratio of 15:1 by mass, and then uniformly laid to prepare a modified fiber board with a thickness of 10mm;

[0091] The softwood pitch plastic film, the modified hemp fiber board and the softwood pitch plastic film were stacked in order, and then hot-pressed at a pressure of 4MPa and a temperature of 120°C for 15min to obtain a hemp fiber molded composite material with a thickness of 11.5mm.

[0092] The bamboo fiber molded composite material prepared in Example 2 was detected according to GB / T 25975-2010 "Exterior thermal insulation composite systems-Sandwich panels with fibre cement facings" and GB / T 11968-2006 "Determination of sound insulating performance of building wall", and the detection results are listed in Table 2.

[0093] Table 2 Performance of the bamboo fiber molded composite material prepared in Example 2

[0094] Density 300 Kg / m 3 ]] Thermal conductivity 0.045 W / mk Breaking stress in bending 55 MPa 10% compression stress ≥ 150 Kpa Sound insulation class 50

[0095] As can be seen from the data in Table 2, the hemp fiber molded composite material prepared in Example 2 meets the strength, thermal insulation and sound insulation requirements of the hemp fiber molded composite material on the wallboard.

[0096] Although the above examples make a detailed description of the present application, it is only a part of the embodiments of the present application, but not all the embodiments, and people can also obtain other embodiments according to the present embodiments without creativity, which all belong to the protection scope of the present application.

Claims

1. An integrated system for preparing plant fiber molding composite materials, characterized in that, It includes extraction units, modification units, crosslinking units, and composite units; The extraction unit includes an extractant container (1), a cork container (2), an extraction device (3) whose inlet is connected to the outlet of the extractant container (1) and the outlet of the cork container (2) respectively, an extraction liquid container (5) whose inlet is connected to the extraction liquid outlet (3-1) located below the side wall of the extraction device (3), and a waste container (6) whose inlet is connected to the waste outlet (3-2) located at the bottom of the extraction device (3). The modification unit includes a plant fiber container (4), a modification device (7-1) connected to the outlet of the plant fiber container (4) and the outlet of the extract container (5) respectively, a first extractant recovery container (8-1) connected to the first gas outlet (7-1-1) at the top of the modification device (7-1), a modified fiber container (9) connected to the modified fiber outlet (7-1-2) at the bottom of the modification device (7-1), a modified fiber board preparation device (15) connected to the outlet of the modified fiber container (9); a distillation device (7-2) connected to the outlet of the extract container (5), a second extractant recovery container (8-2) connected to the second gas outlet (7-2-1) at the top of the distillation device (7-2), and a cork resin container (10) connected to the cork resin outlet (7-2-2) at the bottom of the distillation device (7-2). The crosslinking unit includes a crosslinking agent container (18), a crosslinking device (19) whose inlet is connected to the outlet of the crosslinking agent container (18) and the outlet of the cork resin container (10) respectively, and a cork resin molding device (13) connected to the bottom outlet of the crosslinking device (19); The composite unit includes a hot pressing molding device (16) connected to the cork resin molding device (13) and the modified fiberboard preparation device (15).

2. The integrated system according to claim 1, characterized in that, It also includes a central control system (12), which is connected to the extraction unit, modification unit, crosslinking unit and composite unit via signals.

3. The integrated system according to claim 1, characterized in that, The extraction device (3) is equipped with a heating structure and a solid-liquid separation structure.

4. The integrated system according to claim 1, characterized in that, The modification device (7-1) is equipped with a heating structure inside; the distillation device (7-2) is equipped with a heating structure inside. The modification device (7-1) and the distillation device (7-2) are connected in parallel.

5. The integrated system according to claim 1, characterized in that, The crosslinking device (19) is equipped with a heating structure inside.

6. A method for preparing plant fiber molding composite materials using the integrated system according to any one of claims 1 to 5, comprising the following steps: The extractant and cork are placed in the extraction apparatus (3) for extraction to obtain an extract; The extract and plant fiber are mixed and modified in a modification device (7-1) to obtain modified fiber; The extract is transferred to a distillation apparatus (7-2) for distillation to obtain cork resin; The cork resin and crosslinking agent are mixed in a crosslinking device (19) to carry out a crosslinking reaction and then formed to obtain a cork resin plastic film; The modified fibers are prepared into modified fiberboard using the modified fiberboard preparation device (15); After placing cork resin plastic films on the upper and lower surfaces of the modified fiberboard, the mixture is hot-pressed in a hot pressing device (16) to obtain a plant fiber molded composite material.

7. The method according to claim 6, characterized in that, The extractant includes a mixture of aliphatic hydrocarbons, alcohols, esters, petroleum ether and ethanol, or acetone; The extraction temperature is 20–80°C, the time is 2–6 hours, and the pressure is 0.1–0.5 MPa.

8. The method according to claim 6, characterized in that, The crosslinking agent includes a multifunctional epoxy crosslinking agent, isocyanate, thermoplastic elastomer, or organic peroxide crosslinking agent; The mass ratio of the cork resin to the crosslinking agent is 1:1 to 100; The cross-linking reaction is carried out at a temperature of 20–200°C for a time of 0.5–4 hours.

9. The method according to claim 6, characterized in that, The hot pressing temperature is 80–180℃, the pressure is 0.1–5MPa, and the time is 5–30min.

10. A plant fiber molding composite material prepared according to any one of claims 6 to 9, characterized in that, It includes a first cork resin plastic film, a modified fiberboard, and a second cork resin plastic film, all laminated together. The modified fiberboard contains plant fibers and cork resin coating the surface of the plant fibers.

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