Method for preparing high-performance sandwich structure composite material by using plant long fibers and plant powder
By using plant long fibers and powder in plant fiber/plastic composite materials, the problem of restriction and low reinforcement effect is solved, and high-performance and low-cost composite materials are achieved.
Patent Information
- Application Number
- CN202411823392.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-03-21
AI Technical Summary
There are limitations in the molding process of existing plant fiber/plastic composites, and the reinforcement effect of plant long fibers is low, resulting in difficulty in reusing production efficiency and resource, and increasing the cost of use.
By using plant long fibers and plant powder to prepare high-performance sandwich structural composites, the steps of drying, mixing, melting composite, laminated laying and hot pressing are adopted to ensure the orientation of the long fibers and the uniform composite of the resin.
The uniform coating of long fibers and the maintenance of the orientation structure are achieved, the biomass usage and mechanical properties are improved, the production cost is reduced, and the performance is close to that of plant long fiber/plastic composites.
Smart Images
Figure CN119659038A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of composite material preparation methods. Background Art
[0002] As a natural carbon-fixing material, biomass resources show their unique environmental advantages. Through scientific and technological innovation, biomass materials are transformed into various commodities, which not only gives these materials practical value, but also helps to effectively reduce the burden on the ecological environment and promote the efficient use of resources. Biomass materials are gradually being used in building materials, packaging materials and transportation fields. It is an irreversible trend for renewable natural resources to replace non-renewable traditional synthetic materials.
[0003] Plant fiber / plastic composite materials use plant fiber as reinforcement and thermoplastic resin as matrix. At present, plant powder is usually used in plant fiber / plastic composite materials because plant powder is easier to obtain, the utilization rate of plant powder is higher in the production process, the production energy consumption is lower, which helps to reduce production costs and has certain cost-effectiveness. In addition, the size of plant powder is relatively small and the fluidity is better, which is conducive to full mixing with plastic, making the composite material more homogeneous. However, plant powder / plastic composite materials have limitations on compression molding, and the strength of plant powder reinforced plastics is still relatively low, which is quite different from plant long fiber reinforced plastics. Compared with short plant powder, plant long fibers have a higher aspect ratio, can better maintain fiber morphology, and provide better reinforcement effect. However, after the directional decomposition of plants, a large amount of waste will be generated, which affects production efficiency and resource recycling, thereby increasing the cost of using plant long fibers. Summary of the invention
[0004] The present invention solves the technical problems of uniformly coating long fibers with thermoplastic resin, maintaining directional structure during fiber processing, increasing biomass usage, and reducing costs, and provides a method for preparing high-performance sandwich structure composite materials using plant long fibers and plant powder.
[0005] The method for preparing a high-performance sandwich structure composite material using plant long fibers and plant powder is specifically carried out in the following steps:
[0006] Step 1: Place the long fiber and powder fiber in a drying oven and dry them until the moisture content is less than 3% for standby use;
[0007] Step 2: Evenly mix the powder fiber, thermoplastic resin powder, coupling agent and lubricant processed in step 1, melt compound them using a twin-screw extruder, and crush them into composite particles after cooling; the mass ratio of the powder fiber and the thermoplastic resin powder is (6:4) to (9:1), the amount of the coupling agent is 3% of the total mass of the powder fiber and the thermoplastic resin powder, and the amount of the lubricant is 1% of the total mass of the powder fiber and the thermoplastic resin powder;
[0008] Step 3, uniformly dispersing the long fibers and coupling agents processed in step 1 on the thermoplastic resin film in turn, and then stacking and paving them as the surface layer, then evenly spreading the composite particles in step 2 as the core layer, and then sequentially paving the long fibers, coupling agents and thermoplastic resin films on the composite particles, and then stacking and paving them as another surface layer, with the same number of paving layers on both sides of the surface layer to obtain a slab; the mass ratio of each layer of long fibers and thermoplastic resin films stacked in the surface layer is (5:5) to (7:3), and the amount of coupling agent used is 3% of the total mass of the long fibers and thermoplastic resin films;
[0009] Step 4: preheat the slab laid in step 3 by pressurizing, and then hot pressing it in a hot press; then cool it, take out the slab, and obtain the high-performance sandwich structure composite material.
[0010] Furthermore, in step 1, the length of the long fiber is greater than 5 cm, the particle size of the powder fiber is 40-200 mesh, the long fiber and the powder fiber are plant fibers, and the plant fibers include bamboo fibers, straw fibers or hemp fibers.
[0011] Furthermore, the thermoplastic resin powder is made of high-density polyethylene, linear low-density polyethylene, polypropylene or polyvinyl chloride.
[0012] Furthermore, the material of the thermoplastic resin film is high-density polyethylene, linear low-density polyethylene, polypropylene or polyvinyl chloride.
[0013] Furthermore, the coupling agent is maleic anhydride grafted polyethylene or maleic anhydride grafted polypropylene.
[0014] Furthermore, the lubricant is stearic acid, polyethylene wax or oxidized polyethylene wax.
[0015] Furthermore, a flame retardant is added when laying the long fibers in step three.
[0016] Furthermore, in step three, the ratio of the total thickness of the surface layers on both sides to the thickness of the core layer is (1:6) to (3:2).
[0017] Furthermore, during the ply laying in step three, the long fibers of each layer are oriented in the same direction or the long fibers of adjacent layers are cross-laid, with a cross-angle of 30° to 90°.
[0018] Furthermore, in step 4, the pressure is applied at 1 MPa for preheating for 3 minutes, and then the pressure is controlled to be 6 MPa and the temperature is controlled to be 160° C. for hot pressing for 3 minutes in a hot press.
[0019] Beneficial effects of the present invention:
[0020] The present invention comprehensively considers the characteristics and manufacturing costs of plant fiber / plastic composite materials of different forms, utilizes long fibers and powders, and prepares a new composite material with balanced cost-effectiveness and excellent performance through structural innovation and preparation process innovation.
[0021] The core layer of the composite material of the present invention is composed of powder fiber and thermoplastic resin, and the surface material is composed of thermoplastic resin composite material reinforced with plant long fiber. The orientation and fixation of the long fiber at a specific position are ensured by hot pressing. The thermoplastic plastic is uniformly compounded with the fiber by changing the form of the thermoplastic plastic. The resin penetration effect is improved by changing the pressurization method during the hot pressing process, and the long fiber is finally able to maintain its original length and reinforcement ability. The use of powder fiber reduces the production cost. Compared with the traditional plant fiber / plastic composite material, the amount of plant fiber component added in the composite material of the present invention is increased from 60% to 80%, and the various mechanical properties such as bending strength, tensile strength and impact strength are greatly improved; compared with the plant long fiber / plastic composite material, there is no significant difference in performance and the cost is greatly reduced.
[0022] The invention is used for preparing plant fiber composite material. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 are photos of the appearance of various composite materials, among which a is a bamboo powder / LLDPE bamboo plastic composite material with a bamboo powder mass content of 60%, b is a bamboo powder / LLDPE bamboo plastic composite material with a bamboo powder mass content of 90%, c is a high-performance sandwich structure composite material with a surface layer thickness of 0.6 mm and a core layer thickness of 3.4 mm, d is a high-performance sandwich structure composite material with a surface layer thickness of 1.2 mm and a core layer thickness of 2.8 mm, e is a laminated bamboo plastic composite material, f is a high-performance sandwich structure composite material with a surface layer thickness of 1.8 mm and a core layer thickness of 2.2 mm, g is a high-performance sandwich structure composite material with a surface layer thickness of 2.4 mm and a core layer thickness of 1.6 mm, and h is a long bamboo fiber / LLDPE composite material with a mass ratio of long bamboo fiber to LLDPE film of 6:4;
[0024] Figure 2 Flexural strength and modulus graphs for a variety of materials;
[0025] Figure 3 Flexural strength and modulus graphs Tensile strength and modulus graphs for a variety of materials;
[0026] Figure 4 The impact strength diagram of various materials. DETAILED DESCRIPTION
[0027] Specific implementation method 1: In this implementation method, a method for preparing a high-performance sandwich structure composite material using plant long fibers and plant powder is specifically carried out in the following steps:
[0028] Step 1: Place the long fiber and powder fiber in a drying oven and dry them until the moisture content is less than 3% for standby use;
[0029] Step 2: Evenly mix the powder fiber, thermoplastic resin powder, coupling agent and lubricant processed in step 1, melt compound them using a twin-screw extruder, and crush them into composite particles after cooling; the mass ratio of the powder fiber and the thermoplastic resin powder is (6:4) to (9:1), the amount of the coupling agent is 3% of the total mass of the powder fiber and the thermoplastic resin powder, and the amount of the lubricant is 1% of the total mass of the powder fiber and the thermoplastic resin powder;
[0030] Step 3, uniformly dispersing the long fibers and coupling agents processed in step 1 on the thermoplastic resin film in turn, and then stacking and paving them as the surface layer, then evenly spreading the composite particles in step 2 as the core layer, and then sequentially paving the long fibers, coupling agents and thermoplastic resin films on the composite particles, and then stacking and paving them as another surface layer, with the same number of paving layers on both sides of the surface layer to obtain a slab; the mass ratio of each layer of long fibers and thermoplastic resin films stacked in the surface layer is (5:5) to (7:3), and the amount of coupling agent used is 3% of the total mass of the long fibers and thermoplastic resin films;
[0031] Step 4: preheat the slab laid in step 3 by pressurizing, and then hot pressing it in a hot press; then cool it, take out the slab, and obtain the high-performance sandwich structure composite material.
[0032] Specific embodiment 2: This embodiment is different from specific embodiment 1 in that: the length of the long fiber in step 1 is greater than 5 cm, the particle size of the powder fiber is 40-200 mesh, the long fiber and the powder fiber are plant fibers, and the plant fibers include bamboo fibers, straw fibers or hemp fibers. The rest is the same as specific embodiment 1.
[0033] Specific implementation method 3: This implementation method is different from specific implementation method 1 or 2 in that the material of the thermoplastic resin powder is high-density polyethylene, linear low-density polyethylene, polypropylene or polyvinyl chloride. Other aspects are the same as specific implementation method 1 or 2.
[0034] Specific embodiment 4: This embodiment is different from specific embodiments 1 to 3 in that the material of the thermoplastic resin film is high-density polyethylene, linear low-density polyethylene, polypropylene or polyvinyl chloride. The rest is the same as specific embodiments 1 to 3.
[0035] Specific embodiment 5: This embodiment is different from specific embodiments 1 to 4 in that the coupling agent is maleic anhydride grafted polyethylene or maleic anhydride grafted polypropylene. The rest is the same as specific embodiments 1 to 4.
[0036] Specific implementation example 6: This implementation example is different from specific implementation examples 1 to 5 in that the lubricant is stearic acid, polyethylene wax or oxidized polyethylene wax. The rest is the same as specific implementation examples 1 to 5.
[0037] Specific implementation method 7: This implementation method is different from specific implementation methods 1 to 6 in that a flame retardant is added when laying long fibers in step 3. The rest is the same as specific implementation methods 1 to 6.
[0038] Specific implementation eight: This implementation differs from specific implementations one to seven in that the ratio of the total thickness of the surface layers on both sides to the thickness of the core layer in step three is (1:6) to (3:2). The rest is the same as specific implementations one to seven.
[0039] Specific embodiment 9: This embodiment is different from specific embodiments 1 to 8 in that: in step 3, when laying the layers, the long fibers of each layer are in the same direction or the long fibers of adjacent layers are laid crosswise, with a crossing angle of 30° to 90°. The rest is the same as specific embodiments 1 to 8.
[0040] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that: Step 4 applies 1 MPa of pressure for preheating for 3 minutes, and then controls the pressure to 6 MPa and the temperature to 160° C. for hot pressing for 3 minutes in the hot press. The rest is the same as specific embodiments 1 to 9.
[0041] The content of the present invention is not limited to the content of the above-mentioned embodiments. The combination of one or several specific embodiments can also achieve the purpose of the invention.
[0042] Example:
[0043] The method for preparing a high-performance sandwich structure composite material using plant long fibers and plant powder is specifically carried out in the following steps:
[0044] Step 1: Place the long bamboo fiber and bamboo powder in a drying oven and dry them until the moisture content is less than 3% for later use;
[0045] Step 2: Evenly mix the bamboo powder, LLDPE powder, MAPE and lubricant zinc stearate treated in step 1, use a twin-screw extruder to set the extruder temperature to 120° C. to melt and compound, and crush into composite particles after cooling; the mass ratio of bamboo powder, LLDPE powder, MAPE and stearic acid is 9:1:0.3:0.1;
[0046] Step 3, uniformly dispersing the long bamboo fiber and MAPE processed in step 1 on the LLDPE film in turn, and then stacking and paving them as the surface layer, then evenly spreading the composite particles in step 2 as the core layer, and then paving the long bamboo fiber, MAPE and LLDPE film on the composite particles in turn, and then stacking and paving them as another surface layer, the number of paving layers of the surface layers on both sides is the same, and a slab is obtained; the mass ratio of each layer of long bamboo fiber, LLDPE film and MAPE stacked and paved in the surface layer is 6:4:0.3;
[0047] Step 4: Preheat the slab laid in step 3 by applying pressure of 1 MPa for 3 minutes, and then hot press it in a hot press at a controlled pressure of 6 MPa and a temperature of 160° C. for 3 minutes; then cool it, take out the plate, and obtain the high-performance sandwich structure composite material.
[0048] High-performance sandwich structure composite materials with surface thickness (total thickness of surface layers on both sides) of 0.6 mm and core layer thickness of 3.4 mm, surface thickness of 1.2 mm and core layer thickness of 2.8 mm, surface thickness of 1.8 mm and core layer thickness of 2.2 mm, and surface thickness of 2.4 mm and core layer thickness of 1.6 mm were prepared respectively.
[0049] Comparative Example:
[0050] The difference between this comparative example and the embodiment is that step three is replaced by:
[0051] The long bamboo fibers processed in step 1, MAPE and the composite particles obtained in step 2 are uniformly dispersed on the LLDPE film in turn, stacked and paved, and then the LLDPE film is laid on the upper layer to obtain a slab; the mass ratio of the long bamboo fibers, the LLDPE film, the MAPE and the composite particles is 6:4:0.3:12.5, and the rest is the same as in the embodiment, to prepare a laminated bamboo-plastic composite material.
[0052] Figure 1 These are appearance photos of various composite materials, among which a is a bamboo powder / LLDPE bamboo-plastic composite material with a bamboo powder mass content of 60%, b is a bamboo powder / LLDPE bamboo-plastic composite material with a bamboo powder mass content of 90%, c is a high-performance sandwich structure composite material with a surface layer thickness of 0.6 mm and a core layer thickness of 3.4 mm, d is a high-performance sandwich structure composite material with a surface layer thickness of 1.2 mm and a core layer thickness of 2.8 mm, e is a laminated bamboo-plastic composite material (comparative example), f is a high-performance sandwich structure composite material with a surface layer thickness of 1.8 mm and a core layer thickness of 2.2 mm, g is a high-performance sandwich structure composite material with a surface layer thickness of 2.4 mm and a core layer thickness of 1.6 mm, and h is a long bamboo fiber / LLDPE composite material with a long bamboo fiber and LLDPE film mass ratio of 6:4.
[0053] Figure 2 Flexural strength and modulus graphs for a variety of materials; Figure 3 Flexural strength and modulus graphs Tensile strength and modulus graphs for a variety of materials; Figure 4 The impact strength diagram of various materials.
[0054] like Figures 2 to 4 As shown in the figure, the biomass content of the sandwich bamboo-plastic composite material with a surface layer thickness of 1.8 mm and a core layer thickness of 2.2 mm is close to 76%. Its bending strength and modulus are significantly improved compared with the core layer material bamboo powder reinforced LLDPE composite material, and are similar to the performance of the surface material long fiber reinforced LLDPE composite material. The tensile strength and modulus of the sandwich bamboo-plastic composite material are higher than those of the bamboo-plastic composite material with only bamboo powder. The impact strength of the sandwich bamboo-plastic composite material is still much higher than that of the bamboo-plastic composite material reinforced with bamboo powder, and is also higher than that of the laminated bamboo-plastic composite material at the same fiber content.
Claims
1. A method for preparing a high-performance sandwich structure composite material using plant long fibers and plant powder, characterized in that The method is specifically carried out in the following steps: Step 1: Place the long fiber and powder fiber in a drying oven and dry them until the moisture content is less than 3% for standby use; Step 2: Evenly mix the powder fiber, thermoplastic resin powder, coupling agent and lubricant processed in step 1, melt compound them using a twin-screw extruder, and crush them into composite particles after cooling; the mass ratio of the powder fiber and the thermoplastic resin powder is (6:4) to (9:1), the amount of the coupling agent is 3% of the total mass of the powder fiber and the thermoplastic resin powder, and the amount of the lubricant is 1% of the total mass of the powder fiber and the thermoplastic resin powder; Step 3, uniformly dispersing the long fibers and coupling agents processed in step 1 on the thermoplastic resin film in turn, and then stacking and paving them as the surface layer, then evenly spreading the composite particles in step 2 as the core layer, and then sequentially paving the long fibers, coupling agents and thermoplastic resin films on the composite particles, and then stacking and paving them as the other surface layer, the number of paving layers of the surface layers on both sides is the same, and a slab is obtained; The mass ratio of each layer of long fiber and thermoplastic resin film in the surface layer is (5:5) to (7:3), and the amount of coupling agent is 3% of the total mass of the long fiber and thermoplastic resin film; Step 4: preheat the slab laid in step 3 by pressurizing, and then hot pressing it in a hot press; then cool it, take out the slab, and obtain the high-performance sandwich structure composite material.
2. The method for preparing a high-performance sandwich structure composite material using plant long fibers and plant powder according to claim 1, characterized in that In step 1, the length of the long fiber is greater than 5 cm, the particle size of the powder fiber is 40-200 mesh, the long fiber and the powder fiber are plant fibers, and the plant fibers include bamboo fibers, straw fibers or hemp fibers.
3. The method for preparing a high-performance sandwich structure composite material using plant long fibers and plant powder according to claim 1, characterized in that The material of the thermoplastic resin powder is high-density polyethylene, linear low-density polyethylene, polypropylene or polyvinyl chloride.
4. The method for preparing a high-performance sandwich structure composite material using plant long fibers and plant powder according to claim 1, characterized in that The material of the thermoplastic resin film is high-density polyethylene, linear low-density polyethylene, polypropylene or polyvinyl chloride.
5. The method for preparing a high-performance sandwich structure composite material using plant long fibers and plant powder according to claim 1, characterized in that The coupling agent is maleic anhydride grafted polyethylene or maleic anhydride grafted polypropylene.
6. The method for preparing a high-performance sandwich structure composite material using plant long fibers and plant powder according to claim 1, characterized in that The lubricant is stearic acid, polyethylene wax or oxidized polyethylene wax.
7. The method for preparing a high-performance sandwich structure composite material using plant long fibers and plant powder according to claim 1, characterized in that In step three, flame retardant is added when laying long fibers.
8. The method for preparing a high-performance sandwich structure composite material using plant long fibers and plant powder according to claim 1, characterized in that In step 3, the ratio of the total thickness of the surface layers on both sides to the thickness of the core layer is (1:6) to (3:2).
9. The method for preparing a high-performance sandwich structure composite material using plant long fibers and plant powder according to claim 1, characterized in that During the layer laying in step three, the long fibers of each layer are in the same direction or the long fibers of adjacent layers are laid crosswise with a crossing angle of 30° to 90°.
10. The method for preparing a high-performance sandwich structure composite material using plant long fibers and plant powder according to claim 1, characterized in that Step 4: Apply pressure of 1 MPa and preheat for 3 minutes, then control the pressure to 6 MPa and the temperature to 160°C in the hot press for 3 minutes.