Preparation process of bamboo-plastic composite material with high strength and flame retardant property

Abstract

The invention relates to the technical field of preparation of bamboo-plastic composite materials, and discloses a preparation process of a bamboo-plastic composite material with high strength and flame retardance, which comprises the following steps: S1, pretreatment of bamboo fibers: after the bamboo fibers are treated by alkali liquor, carrying out surface grafting modification by using a silane coupling agent, and carrying out high-pressure steam explosion to obtain bamboo fibers; refining a fiber surface pore structure; s2, compounding a flame retardant, namely performing nano-scale compounding on the intumescent flame retardant and nano-montmorillonite through a mechanical ball milling method; through three-stage modification of alkali treatment, silane coupling and dynamic crosslinking, interface bonding between the bamboo fibers and a polymer matrix is greatly improved, the bending strength is improved by 53%, when the material is stressed, stress can be better transmitted between the bamboo fibers and the matrix, the phenomena of interface debonding, fiber pulling-out and the like are effectively avoided, and the service life of the material is prolonged. Therefore, the overall strength and toughness of the composite material are remarkably improved, and the composite material can bear larger external force in practical application.

Description

Technical Field

[0001] The present invention relates to the technical field of bamboo-plastic composite material preparation, in particular to a process for preparing a bamboo-plastic composite material with high strength and flame retardancy. Background Art

[0002] Bamboo-plastic composite materials are made by adding bamboo fibers or bamboo powder as reinforcing materials or fillers to thermoplastics, and then compounding the bamboo with the molten thermoplastics by heating. Or it refers to a material made by injecting organic monomers into the microstructure of bamboo, and then using radiation or catalytic methods to produce graft copolymers or homopolymers of the organic monomers and bamboo components.

[0003] Traditionally, the interfacial bonding between bamboo fiber and a polymer matrix is poor. Due to the presence of numerous polar hydroxyl groups on the bamboo fiber surface and the typically non-polar or weakly polar polymer matrix, the compatibility between the two is poor. This results in ineffective stress transfer between the bamboo fiber and the matrix when the material is subjected to stress, leading to interfacial debonding and fiber pullout. This limits the overall strength and toughness of the composite material and makes it susceptible to damage when subjected to significant external forces. Therefore, a process for preparing a bamboo-plastic composite with high strength and flame retardancy was proposed. Summary of the Invention

[0004] The object of the present invention is to provide a process for preparing a bamboo-plastic composite material with high strength and flame retardancy, so as to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a process for preparing a bamboo-plastic composite material with high strength and flame retardancy, comprising the following steps:

[0006] S1, bamboo fiber pretreatment, after treating the bamboo fiber with alkali solution, using silane coupling agent to perform surface grafting modification, and high-pressure steam explosion to refine the pore structure of the fiber surface;

[0007] S2, flame retardant compounding, the intumescent flame retardant and nano-montmorillonite are compounded at the nano level by mechanical ball milling;

[0008] S3, melt blending, mixing polypropylene, polylactic acid, bamboo fiber and flame retardant evenly in a tank;

[0009] S4, mixing evenly, feeding the raw materials in sections into a twin-screw extruder for melt blending;

[0010] S5, dynamic crosslinking, adding maleic anhydride grafts during the melt blending process to initiate a dynamic crosslinking reaction in the screw shear zone;

[0011] S6. Compression molding: hot pressing the blended material into a mold.

[0012] Preferably, in the above-mentioned S1, the pressure of the high-pressure steam explosion is 1.2-1.5 MPa, the processing time of the high-pressure steam explosion is 15-20 minutes, the temperature of the high-pressure steam explosion is 180-220° C., and the concentration of the alkali solution is: 3%-8% sodium hydroxide.

[0013] Preferably, in the above step S2, the intumescent flame retardant is a compound of melamine phosphate and pentaerythritol, and the ratio of melamine phosphate to pentaerythritol is 2:1;

[0014] The nano-montmorillonite is treated by intercalation with hexadecyltrimethylammonium bromide.

[0015] Preferably, in the above-mentioned S3, a mixing assembly is provided on one side of the top of the tank body, a cover plate for adding materials is hingedly connected to the top of the tank body, and a discharge pipe is connected to the bottom of the tank body.

[0016] Preferably, in the above step S4, the temperature of the melt blending is 160-190° C., and the screw speed of the twin-screw extruder is 180-220 r / min.

[0017] Preferably, in step S5, the dynamic crosslinking reaction time is 30-60 s, and the shear rate is 500-800 s. -1 .

[0018] Preferably, the mixing assembly comprises a motor and a second rotating shaft, blades and a fixing frame are fixed to the outside of the second rotating shaft, and the number of the blades is several;

[0019] The output shaft end of the motor is fixed with a first conical tooth, the first conical tooth is meshedly connected with a second conical tooth, and the bottom of the second conical tooth is fixed to the top of the second rotating shaft.

[0020] Preferably, the second rotating shaft is provided with a second sliding groove, the inside of the second sliding groove is slidably connected to the first rotating shaft via a sealing sleeve, the first rotating shaft can reciprocate up and down in the second sliding groove, and a first connecting rod is hinged to one side of the first rotating shaft;

[0021] A first sliding groove is provided inside the fixing frame, and a second connecting rod running through one side of the fixing frame is slidably connected to the inside of the first sliding groove, and one end of the first connecting rod is hinged to one side of the second connecting rod.

[0022] Preferably, one end of the second connecting rod is connected to a limit plate via a bolt, and a scraper is fixed to one side of the limit plate;

[0023] A support frame is fixed on one side of the top of the tank body, an electric push rod is fixed on one side of the support frame, a limit block is fixed on the push rod end of the electric push rod, and the bottom of the limit block is rotatably connected to the top of the first rotating shaft.

[0024] Preferably, the above-mentioned: the outer side of the second rotating shaft is rotatably connected to the top side of the tank body through a sealed bearing, the bottom of the motor is fixed to the top side of the tank body, and a protective box located on the outside of the motor and the electric push rod is fixed to the top of the tank body, and a plurality of heat dissipation holes are opened on the surface of the protective box.

[0025] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0026] First, through the three-stage modification of alkali treatment-silane coupling-dynamic cross-linking, the interfacial bonding between bamboo fiber and polymer matrix is greatly improved, and the bending strength is increased by 53%. When the material is subjected to stress, the stress can be better transferred between the bamboo fiber and the matrix, effectively avoiding phenomena such as interface debonding and fiber pull-out, thereby significantly improving the overall strength and toughness of the composite material, enabling it to withstand greater external forces in practical applications.

[0027] 2. The intumescent flame retardant and nano-montmorillonite form a "gas phase-condensed phase" dual barrier mechanism. When the material burns, the IFR rapidly expands to form a carbon foam layer, blocking the transfer of oxygen and heat, and playing a gas-phase flame retardant role; the nano-montmorillonite forms a physical barrier layer in the condensed phase, preventing the diffusion of combustible gases and heat transfer, greatly slowing down the burning rate of the material, reducing the fire hazard, and providing a guarantee for the application of the material in fields with high fire safety requirements.

[0028] 3. Halogen-free addition in the entire process avoids the environmental pollution and health hazards caused by halogens in traditional flame retardant materials. Halogen flame retardants release toxic and harmful gases during combustion, which have a serious impact on the environment and human health. This process adopts a halogen-free flame retardant system, which meets environmental protection requirements and is beneficial to protecting the ecological environment and human health.

[0029] Fourth, the second rotating shaft is driven by the motor to rotate, and several blades on the outside of the second rotating shaft rotate accordingly, stirring the raw materials such as polypropylene, polylactic acid, bamboo fiber and flame retardant in the tank body, so that the raw materials can be fully dispersed and mixed in the tank body, avoiding local accumulation or stratification of the raw materials, providing more uniform raw materials for the subsequent twin-screw extruder melt blending, and helping to improve the performance uniformity of the final composite material.

[0030] 5. Press the switch group to control the electric push rod to start, which drives a series of components such as the limit block, the first rotating shaft, the first connecting rod, and the second connecting rod to move, and finally makes the scraper contact with the inner wall of the tank to clean the raw materials attached to the inner wall of the tank, avoiding the raw materials from agglomerating or remaining on the inner wall of the tank, and ensuring the cleanliness of the inside of the tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] Figure 1 This is a schematic diagram of the structure of the present invention from a first perspective;

[0033] Figure 2 This is a schematic diagram of the structure from a second viewing angle of the present invention;

[0034] Figure 3 This is a schematic structural diagram of the present invention from a third viewing angle;

[0035] Figure 4 This is a schematic diagram of the blade position structure of the present invention;

[0036] Figure 5 It is a structural schematic diagram of the fixing frame of the present invention;

[0037] Figure 6 It is a schematic diagram of the main cross-sectional structure of the second rotating shaft of the present invention.

[0038] Explanation of the accompanying drawings: 1. Tank body; 21. Motor; 22. First conical tooth; 23. Electric push rod; 24. Support frame; 25. Second conical tooth; 26. Limit block; 27. First rotating shaft; 28. Second rotating shaft; 29. Blade; 210. First connecting rod; 211. Scraper; 212. Fixed frame; 213. Limit plate; 214. Second connecting rod; 215. First slide; 216. Second slide; 3. Cover plate; 4. Protective box; 5. Heat dissipation hole; 6. Discharge pipe. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions under which this application can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in this application without affecting the efficacy and purpose that can be achieved by this application.

[0041] Example

[0042] See also Figure 1-6 The present invention provides a technical solution: a preparation process of a bamboo-plastic composite material with high strength and flame retardancy, comprising the following steps:

[0043] S1. Pretreatment of bamboo fiber: After treating the bamboo fiber with alkali solution, the surface of the bamboo fiber is grafted with a silane coupling agent (KH-530 or KH-570) and the pore structure of the fiber surface is refined by high-pressure steam explosion. The amount of KH-530 or KH-570 is 2-3% of the mass of the bamboo fiber.

[0044] The pressure of the high-pressure steam explosion is 1.2 MPa, the processing time of the high-pressure steam explosion is 18 minutes, the temperature of the high-pressure steam explosion is 200° C., and the concentration of the alkali solution is 5% sodium hydroxide.

[0045] S2. Flame retardant compounding: the intumescent flame retardant and nano-montmorillonite are compounded at the nano level by mechanical ball milling for 2-4 hours;

[0046] The intumescent flame retardant is obtained by compounding melamine phosphate and pentaerythritol, with the ratio of melamine phosphate to pentaerythritol being 2:1; the nano-montmorillonite is treated by intercalation with hexadecyltrimethylammonium bromide.

[0047] S3, melt blending, mixing polypropylene, polylactic acid, bamboo fiber and flame retardant uniformly using tank 1;

[0048] A mixing assembly is provided on one side of the top of the tank body 1 , a cover plate 3 for adding materials is hinged on the top of the tank body 1 , and a discharge pipe 6 is connected to the bottom of the tank body 1 , on which a valve is installed.

[0049] S4, mixing evenly, feeding the raw materials in sections into a twin-screw extruder for melt blending;

[0050] The temperature of the melt blending was 180° C., and the screw speed of the twin-screw extruder was 200 r / min.

[0051] S5, dynamic crosslinking, adding maleic anhydride grafts during the melt blending process to initiate a dynamic crosslinking reaction in the screw shear zone; the dynamic crosslinking reaction time is 30-60s, and the shear rate is 500-800s -1 ;

[0052] S6. Compression molding: hot pressing the blended material into a mold.

[0053] The mechanical properties test data of the composite material of this embodiment are as follows:

[0054] Test items The composite material of this embodiment Traditional bamboo plastic materials Bending strength 49.2Mpa 32.1Mpa tensile strength 38.7Mpa 26.8Mpa Notched impact strength <![CDATA[6.5KJ / m 2 ]]> <![CDATA[4.2KJ / m 2 ]]> density <![CDATA[1.18g / cm 3 ]]> <![CDATA[1.45g / cm 3 ]]>

[0055] The composite material of this embodiment has a flexural strength increased by 53% and a density reduced by 18.6% compared to conventional materials.

[0056] The flame retardant performance test data of the composite material of this embodiment are as follows:

[0057] Test items This embodiment Traditional bamboo plastic materials Vertical combustion level V-0 (1.6mm thickness) V-0 (3mm thickness) Limiting oxygen index 33.8％ 28.5％ Smoke density level 72 105 Peak heat release rate <![CDATA[112kW / m 2 ]]> <![CDATA[298kW / m 2 ]]> Total heat release <![CDATA[18.7MJ / m 2 ]]> <![CDATA[34.2MJ / m 2 ]]>

[0058] The composite material of this embodiment achieves higher flame retardant efficiency with a lower addition amount, breaking through the bottleneck of traditional bamboo-plastic materials that cannot achieve both thickness and flame retardant grade.

[0059] The mixing assembly includes a motor 21 and a second rotating shaft 28, and a blade 29 and a fixing frame 212 are fixed to the outside of the second rotating shaft 28, and the number of the blades 29 is several; a first conical tooth 22 is fixed to the output shaft end of the motor 21, and the first conical tooth 22 is meshed and connected with the second conical tooth 25, and the bottom of the second conical tooth 25 is fixed to the top of the second rotating shaft 28, and a second chute 216 is opened inside the second rotating shaft 28, and the bottom of the inner wall of the second chute 216 is provided with an inclined slope to facilitate the discharge of raw materials. The inside of the second chute 216 is slidably connected to the first rotating shaft 27 through a sealing sleeve, and the sealing sleeve (not shown in the figure) can make the first rotating shaft 27 rotate and move up and down without leakage. The sealing sleeve meets the requirements of rotary sealing and axial sliding at the same time. The first rotating shaft 27 can reciprocate up and down in the second chute 216, and a first connecting rod 210 is hinged on one side of the first rotating shaft 27;

[0060] A first slide groove 215 is provided inside the fixing frame 212, and a second connecting rod 214 is slidably connected to the inside of the first slide groove 215 and passes through one side of the fixing frame 212. One end of the first connecting rod 210 is hinged to one side of the second connecting rod 214. When the first rotating shaft 27 reciprocates up and down, one end of the second connecting rod 214 is connected to the limiting plate 213 by a bolt, and a scraper 211 is fixed to one side of the limiting plate 213. Therefore, the sliding of the second connecting rod 214 will drive the scraper 211 to contact the inner wall of the tank body 1 to clean the raw materials attached to the inner wall of the tank body 1. The second connecting rod 214 is driven by the first connecting rod 210 to slide in the first slide groove 215 provided inside the fixing frame 212, and one end of the first connecting rod 210 is hinged to one side of the second connecting rod 214.

[0061] One end of the second connecting rod 214 is connected to the limiting plate 213 by a bolt, and a scraper 211 is fixed to one side of the limiting plate 213; a support frame 24 is fixed to one side of the top of the tank body 1, and an electric push rod 23 is fixed to one side of the support frame 24. The limit block 26 is fixed to the push rod end of the electric push rod 23, and the bottom of the limit block 26 is rotatably connected to the top of the first rotating shaft 27. The outer side of the second rotating shaft 28 is rotatably connected to the top side of the tank body 1 through a sealed bearing. The bottom of the motor 21 is fixed to the top side of the tank body 1, and a protective box 4 located on the outside of the motor 21 and the electric push rod 23 is fixed to the top of the tank body 1. A plurality of heat dissipation holes 5 are provided on the surface of the protective box 4.

[0062] Working principle: Open the cover 3, add polypropylene, polylactic acid, bamboo fiber and flame retardant into the tank body 1, press the switch group to control the motor 21 to start, and the first conical teeth 22 fixed to the output shaft end thereof begin to rotate. The first conical teeth 22 interact with the meshing second conical teeth 25 to transmit power to the second conical teeth 25. The bottom of the second conical teeth 25 is fixed to the top of the second rotating shaft 28, so the second rotating shaft 28 will rotate with the rotation of the second conical teeth 25. A plurality of blades 29 are fixed to the outside of the second rotating shaft 28. When the second rotating shaft 28 rotates, the blades 29 rotate accordingly, stirring the raw materials in the tank body 1 and preliminarily mixing the raw materials.

[0063] When the raw materials are evenly mixed, the valve on the discharge pipe 6 is opened to discharge the raw materials, and the switch group is pressed to control the electric push rod 23 and the motor 21 to start. The limit block 26 fixed at the push rod end begins to move downward, and the bottom of the limit block 26 is rotatably connected to the top of the first rotating shaft 27. Therefore, the movement of the limit block 26 will drive the first rotating shaft 27 to reciprocate up and down in the second chute 216. A first connecting rod 210 is hinged to one side of the first rotating shaft 27, and one end of the first connecting rod 210 is hinged to one side of the second connecting rod 214. When When the first rotating shaft 27 reciprocates up and down, the second connecting rod 214 is driven by the first connecting rod 210 to slide in the first sliding groove 215 opened inside the fixing frame 212. One end of the second connecting rod 214 is connected to the limiting plate 213 by a bolt. A scraper 211 is fixed to one side of the limiting plate 213. Therefore, the sliding of the second connecting rod 214 will drive the scraper 211 to contact the inner wall of the tank body 1. The scraper 211 rotates to clean the raw materials attached to the inner wall of the tank body 1, thereby preventing the raw materials from agglomerating or remaining on the inner wall of the tank body 1 and ensuring the mixing effect.

[0064] The protective box 4 can protect the motor 21 and the electric push rod 23 from splashing or damage caused by external debris. The surface of the protective box 4 is provided with a plurality of heat dissipation holes 5, which are conducive to heat dissipation of the motor 21 and the electric push rod 23 during operation to ensure their normal operation.

[0065] In summary, the three-stage modification process of alkali treatment, silane coupling, and dynamic crosslinking significantly improves the interfacial bonding between the bamboo fiber and the polymer matrix. The flexural strength is increased by 53%. When the material is subjected to stress, stress is better transferred between the bamboo fiber and the matrix, effectively preventing interfacial debonding and fiber pullout. This significantly improves the overall strength and toughness of the composite material, enabling it to withstand greater external forces in practical applications.

[0066] The intumescent flame retardant and nano-montmorillonite form a dual "gas-phase-condensed phase" barrier mechanism. When the material burns, the IFR rapidly expands to form a carbon foam layer, blocking the transfer of oxygen and heat, acting as a gas-phase flame retardant. The nano-montmorillonite forms a physical barrier in the condensed phase, preventing the diffusion of combustible gases and heat transfer. This significantly slows the material's combustion rate and reduces the risk of fire, ensuring its application in areas with high fire safety requirements.

[0067] The entire process is halogen-free, eliminating the environmental pollution and health hazards associated with halogens in traditional flame-retardant materials. Halogen-based flame retardants release toxic and harmful gases during combustion, severely impacting the environment and human health. This process utilizes a halogen-free flame-retardant system, meeting environmental requirements and contributing to the protection of the ecological environment and human health.

[0068] The second rotating shaft 28 is driven to rotate by the motor 21, and the plurality of blades 29 on the outer side of the second rotating shaft 28 rotate accordingly, stirring the raw materials such as polypropylene, polylactic acid, bamboo fiber and flame retardant in the tank body 1, so that the raw materials can be fully dispersed and mixed in the tank body 1, avoiding local accumulation or stratification of the raw materials, providing more uniform raw materials for the subsequent twin-screw extruder melt blending, and helping to improve the performance uniformity of the final composite material.

[0069] Pressing the switch group controls the electric push rod 23 to start, driving a series of components such as the limit block 26, the first rotating shaft 27, the first connecting rod 210, and the second connecting rod 214 to move, and finally making the scraper 211 contact the inner wall of the tank body 1 to clean the raw materials attached to the inner wall of the tank body 1, thereby avoiding the raw materials from caking or remaining on the inner wall of the tank body 1 and ensuring the cleanliness of the inside of the tank body 1.

[0070] Those skilled in the art will appreciate that various combinations and / or combinations of features described in the various embodiments and / or claims of the present invention may be made, even if such combinations and / or combinations are not explicitly described in the present invention. In particular, various combinations and / or combinations of features described in the various embodiments and / or claims of the present invention may be made, without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.

Claims

1. A process for preparing a bamboo-plastic composite material with high strength and flame retardancy, characterized in that: The following steps are involved: S1, bamboo fiber pretreatment, after treating the bamboo fiber with alkali solution, using silane coupling agent to perform surface grafting modification, and high-pressure steam explosion to refine the pore structure of the fiber surface; S2, flame retardant compounding, the intumescent flame retardant and nano-montmorillonite are compounded at the nano level by mechanical ball milling; S3, melt blending, mixing polypropylene, polylactic acid, bamboo fiber and flame retardant uniformly using a tank (1); S4, mixing evenly, feeding the raw materials in sections into a twin-screw extruder for melt blending; S5, dynamic crosslinking, adding maleic anhydride grafts during the melt blending process to initiate a dynamic crosslinking reaction in the screw shear zone; S6. Compression molding: hot pressing the blended material into a mold.

2. The process for preparing a bamboo-plastic composite material with high strength and flame retardancy according to claim 1, characterized in that: In S1, the pressure of the high-pressure steam explosion is 1.2-1.5 MPa, the processing time of the high-pressure steam explosion is 15-20 minutes, the temperature of the high-pressure steam explosion is 180-220° C., and the concentration of the alkali solution is 3%-8% sodium hydroxide.

3. The process for preparing a bamboo-plastic composite material with high strength and flame retardancy according to claim 1, characterized in that: In S2, the intumescent flame retardant is obtained by compounding melamine phosphate and pentaerythritol, and the ratio of melamine phosphate to pentaerythritol is 2:1; The nano-montmorillonite is treated by intercalation with hexadecyltrimethylammonium bromide.

4. The process for preparing a bamboo-plastic composite material with high strength and flame retardancy according to claim 1, wherein: In S3, a mixing assembly is provided on one side of the top of the tank body (1), a cover plate (3) for adding materials is hingedly connected to the top of the tank body (1), and a discharge pipe (6) is connected to the bottom of the tank body (1).

5. The process for preparing a bamboo-plastic composite material with high strength and flame retardancy according to claim 1, characterized in that: In S4, the temperature of the melt blending is 160-190° C., and the screw speed of the twin-screw extruder is 180-220 r / min.

6. The process for preparing a bamboo-plastic composite material with high strength and flame retardancy according to claim 1, characterized in that: In S5, the reaction time of the dynamic crosslinking is 30-60s, and the shear rate is 500-800s. -1 .

7. The process for preparing a bamboo-plastic composite material with high strength and flame retardancy according to claim 4, characterized in that: The mixing assembly comprises a motor (21) and a second rotating shaft (28), wherein blades (29) and a fixing frame (212) are fixed on the outside of the second rotating shaft (28), and the number of the blades (29) is several; A first conical tooth (22) is fixed to the output shaft end of the motor (21), the first conical tooth (22) is meshedly connected with a second conical tooth (25), and the bottom of the second conical tooth (25) is fixed to the top of the second rotating shaft (28).

8. The process for preparing a bamboo-plastic composite material with high strength and flame retardancy according to claim 7, characterized in that: A second sliding groove (216) is provided inside the second rotating shaft (28), and the inside of the second sliding groove (216) is slidably connected to the first rotating shaft (27) through a sealing sleeve. The first rotating shaft (27) can reciprocate up and down in the second sliding groove (216), and a first connecting rod (210) is hinged on one side of the first rotating shaft (27); A first sliding groove (215) is provided inside the fixing frame (212), and a second connecting rod (214) that passes through one side of the fixing frame (212) is slidably connected to the inside of the first sliding groove (215), and one end of the first connecting rod (210) is hinged to one side of the second connecting rod (214).

9. The process for preparing a bamboo-plastic composite material with high strength and flame retardancy according to claim 8, characterized in that: One end of the second connecting rod (214) is connected to a limiting plate (213) via a bolt, and a scraper (211) is fixed to one side of the limiting plate (213); A support frame (24) is fixed on one side of the top of the tank body (1), an electric push rod (23) is fixed on one side of the support frame (24), a limit block (26) is fixed on the push rod end of the electric push rod (23), and the bottom of the limit block (26) is rotatably connected to the top of the first rotating shaft (27).

10. The process for preparing a bamboo-plastic composite material with high strength and flame retardancy according to claim 9, characterized in that: The outer side of the second rotating shaft (28) is rotatably connected to the top side of the tank body (1) through a sealed bearing, the bottom of the motor (21) is fixed to the top side of the tank body (1), and a protective box (4) located outside the motor (21) and the electric push rod (23) is fixed to the top of the tank body (1), and a plurality of heat dissipation holes (5) are opened on the surface of the protective box (4).

Images