Bamboo-plastic material mixing device and mixing method

Abstract

The invention provides a bamboo-plastic material mixing device and a bamboo-plastic material mixing method, and relates to the field of bamboo-plastic processing. The bamboo-plastic material mixing method comprises the following steps: crushing, sorting and drying a bamboo base, mixing a branch suspension and the bamboo base, drying for the second time, keeping the overall water content below 5%, primarily mixing the bamboo base with a plastic base material, adding 30% of the total initiating dosage, heating and mixing the bamboo base with the plastic base material, and discharging steam. The bamboo-plastic material mixing method comprises the following steps: firstly, fully mixing the grafting suspension with the bamboo fibers, then drying, fully wrapping the surfaces of the bamboo fibers with the grafting substances, and mixing the plastic base, the bamboo base, the grafting substances and the initiator in a low-temperature environment, so that the bamboo-plastic material is obtained. And then the initiator is supplemented in a high-temperature stirring environment, so that the grafting object can be in full contact with the bamboo base and the plastic base to complete grafting.

Description

Technical Field

[0001] This invention relates to the field of bamboo plastic processing, specifically to a bamboo plastic material mixing device and mixing method. Background Technology

[0002] Bamboo-plastic composites are environmentally friendly new materials made from thermoplastic plastics such as polypropylene and polyethylene as the matrix, with bamboo fiber or bamboo powder added as reinforcing materials, and processed through extrusion, injection molding, and other processes. Increased bamboo powder content improves the material's rigidity and provides properties such as moisture resistance, corrosion resistance, and recyclability. It is widely used in building materials, industrial packaging, and other fields. During the production process, grafting agents are added to ensure a strong bond between the bamboo fibers and the plastic.

[0003] Existing patents disclose a bamboo-plastic composite foam material and its preparation method. This bamboo-plastic composite foam material is made by mixing bamboo fiber as a base material, low-density polyethylene resin, and appropriate amounts of additives such as maleic anhydride grafted polyolefin, azodicarbonamide as a foaming agent, zinc oxide as a foaming aid, antioxidant 1010, and liquid paraffin as a lubricant. The bamboo fiber content in the base material is 50-80 wt%, and the low-density polyethylene resin content is 20-50 wt%. The bamboo-plastic composite material of this invention has low cost, high physical and mechanical strength, good surface finish, water and chemical corrosion resistance, and is easily degradable, with a wide range of applications. It is a green and environmentally friendly substitute for wood and plastic. However, in this technical solution, the grafting material does not achieve sufficient contact with the bamboo fiber and plastic, therefore a new mixing method and mixing device are needed. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a bamboo-plastic material mixing device and mixing method, which solves the problems mentioned in the background section.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for mixing bamboo-plastic materials, comprising the following steps:

[0006] S1, bamboo-based crushing, sorting, and drying;

[0007] S2, the suspension is mixed with bamboo substrate;

[0008] S3, secondary drying, to maintain the overall moisture content below 5%;

[0009] S4, bamboo is initially mixed with plastic substrate and added at 30% of the total initiator dosage;

[0010] S5, bamboo-based plastic substrate heating and mixing with steam exhaust;

[0011] S6, injected into the twin-screw extruder and the remaining initiator added, extruded, mixed and discharged.

[0012] Preferably, S1 includes the following steps:

[0013] 1. After removing the nodes, the bamboo is split in half and then pressed by an extrusion mechanism until the fibers are separated.

[0014] 2. Soak and rinse the bamboo fiber with lignin removal solution, clean the bamboo fiber with water, and crush the bamboo fiber to 2-5cm using a crushing mechanism.

[0015] 3. Dry the bamboo fiber until the moisture content is between 1-3%.

[0016] Preferably, S1 includes the following steps:

[0017] 1. Sediment from bamboo grinding powder liquid, or by-products from bamboo pulping and papermaking processes, and remove the supernatant;

[0018] 2. Use a double-layer filter screen to filter the sediment, so that the particle size of the sediment is between 40 mesh and 200 mesh;

[0019] 3. Soak and rinse the bamboo powder with lignin removal solution, clean the bamboo powder with water, and dehydrate it;

[0020] 4. Dry the bamboo powder until the moisture content is between 1-3%.

[0021] Preferably, the mixing of the graft suspension with the bamboo substrate and the secondary drying are carried out in the same device. The bamboo substrate is blown up by the air supply mechanism and sprayed with the graft suspension from above. After spraying, hot air is switched to blow the bamboo substrate up and dry it.

[0022] Preferably, the initial mixing of the plastic substrate, heating and mixing, and steam discharge are carried out in the same device, and the outlet of the device and the inlet of the twin-screw extruder are provided with an openable and closable connecting part;

[0023] Preferably, the bamboo-based plastic base and initiator are placed inside the device, and the bamboo-based and plastic base are initially mixed without activating the heating unit. After the initial mixing is completed, the heating unit is activated to heat and mix the materials. During the later stage of heating and mixing, the steam emission unit operates intermittently.

[0024] A bamboo-plastic material mixing device, used in steps S2 and S3, includes a cavity for support, with gas passage openings around the cavity, a liftable bottom blowing plate at the bottom of the cavity, a suspension spraying unit threadedly connected to the top of the cavity, a cover plate for replacing the suspension spraying unit threadedly connected to the top of the cavity, and a gas circulation unit connected to the outer ring of the cavity that can exchange the air intake and exhaust directions. The air intake end of the gas circulation unit is connected to a gas heating unit for heating the air intake together with the bottom blowing plate.

[0025] Preferably, the gas circulation unit includes a separate gas chamber that communicates with the cavity and is disposed on the outer ring of the cavity. The gas chambers are connected by connecting pipes. The two connecting pipes are connected to an outlet of the gas heating unit and an exhaust port by an electromagnetic reversing valve. The electromagnetic reversing valve is used to switch the connection between the two connecting pipes and the outlet of the gas heating unit.

[0026] Preferably, the gas circulation unit includes a sleeve disposed on the outside of the cavity. The sleeve rotates around the cavity under the action of the drive unit. The inside of the sleeve is divided into multiple air chambers by a partition. The air chambers are connected by a connecting pipe. Two sets of rotating gas supply rings are sleeved on the outer ring of the cavity. One of the rotating gas supply rings is connected to the gas heating unit.

[0027] Preferably, steps S4 and S5 include a housing, an internal stirring unit, a steam exhaust unit in the middle of the housing, a coverable feed inlet at the top of the housing, a discharge outlet at the bottom of the housing, the discharge outlet being connected to the feed inlet of the twin-screw extruder via a tee with a closing unit, a heating unit on the inner wall of the housing, the steam exhaust unit including an exhaust hole on the upper wall of the housing and a gas-gathering hood surrounding the exhaust hole, and a cover on the outer surface of the housing that can be moved to cover the exhaust hole, the cover exposing the exhaust hole when the stirring unit stops working.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The bamboo-plastic material mixing method involves first fully mixing the grafting suspension with bamboo fiber and then drying it, so that the grafting material fully coats the surface of the bamboo fiber. The plastic base, bamboo base, grafting material and initiator are mixed in a low temperature environment, and then the initiator is added in a high temperature stirring environment, so that the grafting material can fully contact the bamboo base and plastic base to complete the grafting.

[0030] 2. The bamboo-plastic material mixing device has a suspension spraying unit threadedly connected to the top of the cavity, and a cover plate for replacing the suspension spraying unit is also threadedly connected to the top of the cavity. The outer ring of the cavity is equipped with a gas circulation unit that communicates with the cavity and can exchange the air intake and exhaust directions. The air intake end of the gas circulation unit is connected to a gas heating unit for heating the air intake together with the bottom blowing plate. With this configuration, the bamboo fiber can be blown up and dispersed by air, so that it can come into more full contact with the receiving suspension, and then the water in the receiving suspension can be heated and dried.

[0031] 3. The bamboo-plastic material mixing device includes a gas circulation unit comprising a separate air chamber connected to the cavity and located on the outer ring of the cavity. The air chambers are connected by connecting pipes. The two connecting pipes are connected to an outlet of the gas heating unit and an exhaust port by an electromagnetic reversing valve. The electromagnetic reversing valve is used to switch the connection between the two connecting pipes and the outlet of the gas heating unit. During the heating and drying process, the air inlet and exhaust port of the cavity alternate under the action of the electromagnetic reversing valve, thereby changing the direction of gas drying and preventing the accumulation of bamboo fibers.

[0032] 4. The bamboo-plastic material mixing device has a mixing unit inside the outer shell, a steam exhaust unit in the middle of the outer shell, a coverable feed port at the top of the outer shell, and a discharge port at the bottom of the outer shell. The discharge port is connected to the feed port of the twin-screw extruder through a tee with a closing unit. A heating unit is installed on the inner wall of the outer shell. The steam exhaust unit includes an exhaust hole on the upper wall of the outer shell and a gas-gathering hood surrounding the exhaust hole. The outer surface of the outer shell has a cover that can be moved to cover the exhaust hole. When the mixing unit stops working, the cover will expose the exhaust hole. This design can prevent the bamboo and plastic base from being squeezed during the operation of the mixing unit and prevent them from being discharged from the exhaust hole. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the cavity connection of the present invention;

[0034] Figure 2 This is a schematic diagram of the suspension spraying unit of the present invention;

[0035] Figure 3 This is a half-sectional schematic diagram of the sleeve of the present invention;

[0036] Figure 4 This is a half-sectional schematic diagram of the cavity of the present invention;

[0037] Figure 5 This is a schematic diagram of the outer casing connection of the present invention;

[0038] Figure 6 This is a half-sectional schematic diagram of the outer casing of the present invention;

[0039] Figure 7 This is a schematic diagram of the connection of the cover portion of the present invention.

[0040] In the diagram: 1. Cavity; 2. Bottom blowing plate; 3. Suspension spraying unit; 4. Cover plate; 5. Gas circulation unit; 6. Gas heating unit; 501. Gas chamber; 502. Connecting pipe; 503. Electromagnetic reversing valve; 504. Sleeve; 505. Drive unit; 506. Rotary air supply ring; 507. Partition plate; 7. Outer shell; 8. Stirring unit; 9. Steam exhaust unit; 10. Feed inlet; 11. Discharge outlet; 12. T-junction; 13. Heating unit; 901. Exhaust port; 902. Air collection hood; 903. Cover part. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0042] It should be noted that all directional indications in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0043] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0044] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0045] like Figures 1-7 As shown, a method for mixing bamboo-plastic materials includes the following steps:

[0046] S1, bamboo base crushing and sorting, and drying, the bamboo base is cleaned and trimmed bamboo;

[0047] S2, the grafted suspension is mixed with bamboo substrate, and the grafted suspension is maleic anhydride grafted suspension;

[0048] S3, secondary drying, keeping the overall moisture content below 5%. After the graft suspension and bamboo base are mixed, most of the moisture is removed by drying, but some moisture is still retained in the graft suspension. This can prevent the viscosity of the suspension from increasing after complete drying, which would cause the bamboo base to clump together.

[0049] S4, bamboo is initially mixed with plastic substrate and 30% of the total initiator dosage is added. Peroxide is used as the initiator. The initiator is added first and then fully mixed with the grafting suspension to initially form a graft.

[0050] S5, bamboo is heated and mixed with plastic substrate and steam is released to remove moisture from bamboo substrate and graft suspension;

[0051] S6, inject into the twin-screw extruder and add the remaining initiator, squeeze and mix and discharge. In this way, the extrusion and heating of the twin-screw extruder can make the initiator and the grafting material fully mixed to complete the connection between bamboo matrix and plastic matrix.

[0052] S1 includes the following steps:

[0053] 1. After removing the nodes from the bamboo, split it in half. Use an extrusion mechanism to press the bamboo until the fibers are separated. Then, use bamboo pulverizer and use an extrusion mechanism to press the bamboo until the fibers are exposed.

[0054] 2. Soak and rinse the bamboo fibers with sodium chlorite solution to remove lignin and retain the fibers. Clean the bamboo fibers with water to avoid residue. Then, use a crushing machine to crush the bamboo fibers to 2-5cm. Fibers that are too long will result in a rough surface on the finished product, while fibers that are too short will cause the bamboo fibers to clump together.

[0055] 3. Dry the bamboo fiber to a moisture content between 1-3%. The drying mechanism removes most of the moisture from the bamboo fiber while retaining some moisture to prevent carbonization.

[0056] S1 includes the following steps:

[0057] 1. The liquid is derived from bamboo grinding powder or by-products of bamboo pulping and papermaking processes, and the supernatant is removed. The bamboo base used in this technical solution is in powder form, and the use of by-products of bamboo pulping and papermaking processes can realize waste utilization.

[0058] 2. Use a double-layer filter screen to filter the sediment, so that the particle size of the sediment is between 40 mesh and 200 mesh;

[0059] 3. Soak and rinse the bamboo powder with lignin removal solution, clean the bamboo powder with water, and dehydrate it;

[0060] 4. Dry the bamboo powder until the moisture content is between 1-3%.

[0061] The mixing of the graft suspension with the bamboo substrate and the secondary drying are carried out in the same device. The bamboo substrate is blown up by the air supply mechanism and sprayed with the graft suspension from above. After spraying, the hot air is switched to blow up the bamboo substrate and dry it. This can optimize the structure and reduce space occupation.

[0062] Based on the initial mixing of plastic substrate, heating, mixing and steam discharge are carried out in the same device, and the outlet of the device and the inlet of the twin-screw extruder are provided with a connecting part that can be opened and closed;

[0063] Bamboo base, plastic base, and initiator are added into the device. The bamboo base and plastic base are initially mixed without starting the heating unit 13. After the initial mixing is completed, the heating unit 13 is started to heat and mix. During the later stage of heating and mixing, the steam emission unit 9 works intermittently. The initial mixing is carried out to make the raw materials evenly distributed. Then the heating and mixing is carried out to connect the bamboo base and the plastic base. During the heating and stirring process, water is generated in the form of steam. At this time, stirring is stopped and the steam emission unit 9 is turned on to release steam.

[0064] A bamboo-plastic material mixing device, used in steps S2 and S3, includes a cavity 1 for support, with gas passage openings around the cavity 1, a liftable bottom blowing plate 2 at the bottom of the cavity 1, a suspension spraying unit 3 threadedly connected to the top of the cavity 1, a cover plate 4 for replacing the suspension spraying unit 3 threadedly connected to the top of the cavity 1, and a gas circulation unit 5 connected to the outer ring of the cavity 1 for exchanging the air intake and exhaust directions. The air intake end of the gas circulation unit 5 is connected to a gas heating unit 6 for heating the intake air together with the bottom blowing plate 2. With this arrangement, air can be used to blow up and disperse the bamboo fibers, thereby allowing them to come into more thorough contact with the receiving suspension, and then heat and dry the moisture in the receiving suspension.

[0065] The gas circulation unit 5 includes a separate air chamber 501 that is connected to the cavity 1 and disposed on the outer ring of the cavity 1. The air chambers 501 are connected at intervals by connecting pipes 502. The two connecting pipes 502 are connected to one outlet and one exhaust port of the gas heating unit 6 by an electromagnetic reversing valve 503. The electromagnetic reversing valve 503 is used to switch the connection between the two connecting pipes 502 and the outlet of the gas heating unit 6. During the process of heating and drying the gas, the air inlet and air outlet of the cavity 1 alternate under the action of the electromagnetic reversing valve 503, thereby changing the direction of gas drying and preventing the bamboo fiber from accumulating.

[0066] The gas circulation unit 5 includes a sleeve 504 disposed on the outside of the cavity 1. The sleeve 504 rotates around the cavity 1 under the action of the drive unit 505. The inside of the sleeve 504 is divided into multiple air chambers 501 by a partition 507. The air chambers 501 are connected at intervals by a connecting pipe 502. Two sets of rotating air supply rings 506 are sleeved on the outer ring of the cavity 1. One of the rotating air supply rings 506 is connected to the gas heating unit 6. Similarly, the rotation of the sleeve 504 is used to replace the operation of the electromagnetic reversing valve 503. With this arrangement, the switching of the air intake direction and the exhaust direction can be realized relatively easily.

[0067] The steps S4 and S5 include a housing 7, inside which a stirring unit 8 is disposed, and in the middle of the housing 7 a steam exhaust unit 9 is disposed. A coverable feed inlet 10 is disposed on the top of the housing 7, and a discharge outlet 11 is disposed on the bottom of the housing 7. The discharge outlet 11 is connected to the inlet of the twin-screw extruder via a tee 12 with a closing unit. A heating unit 13 is disposed on the inner wall of the housing 7. The steam exhaust unit 9 includes an exhaust hole 901 disposed on the upper wall of the housing 7 and a gas-collecting hood 902 surrounding the exhaust hole 901. The outer surface of the housing 7 is provided with a cover 903 that covers the exhaust hole 901 by movement. The cover 903 includes a cover block and a unit for driving the cover block to move. In the embodiment shown in the drawings, a gear ring is connected to the cover block, and gears drive its movement. When the stirring unit 8 stops working, the cover 903 exposes the exhaust hole 901. This arrangement avoids the squeezing of the bamboo and plastic bases by the stirring unit 8 during operation, preventing them from being discharged from the exhaust hole 901.

[0068] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0069] Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0070] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for mixing bamboo plastic material, characterized in that, The method comprises the following steps: S1, bamboo base crushing and sorting, and drying; S2, mixing the suspension with the bamboo base; S3, secondary drying, keeping the overall moisture content below 5%; S4, initial mixing of the bamboo base and plastic base, and feeding 30% of the total initiator; S5, heating and mixing the bamboo base and plastic base and discharging steam; S6, feeding into a double screw extruder and feeding the remaining initiator, and extruding and discharging.

2. The method according to claim 1, wherein: S1 comprises the following steps: 1, splitting the bamboo after removing the node, and separating the bamboo into fibers through a pressing mechanism; 2, soaking and washing the bamboo fibers with a lignin removal solution, cleaning the bamboo fibers with clean water, and crushing the bamboo fibers to 2-5 cm through a crushing mechanism; 3, drying the bamboo fibers to a moisture content of 1-3%.

3. The method according to claim 1, wherein: S1 comprises the following steps: 1, precipitating the liquid from the bamboo grinding powder or the byproduct from the bamboo pulp papermaking process, and removing the supernatant; 2, filtering the precipitate with a double-layer filter screen so that the particle size of the precipitate is between 40 mesh and 200 mesh; 3, soaking and washing the bamboo powder with a lignin removal solution, cleaning the bamboo powder with clean water, and dehydrating; 4, drying the bamboo powder to a moisture content of 1-3%.

4. The bamboo-plastic material mixing method according to claim 2 or 3, characterized in that: The mixing of the suspension with the bamboo base and the secondary drying are performed in the same device, the bamboo base is blown up by a blowing mechanism, and the suspension is sprayed from above, after the spraying is completed, the bamboo base is blown up and dried by switching to hot air.

5. The method according to claim 4, wherein: The initial mixing of the bamboo base and plastic base, heating and mixing, and discharging steam are performed in the same device, the discharge port of the device is provided with an openable and closable communication part with the inlet of the double screw extruder; The bamboo base and plastic base are initially mixed without starting the heating unit, the heating unit is started for heating and mixing after the initial mixing is completed, and the steam discharge unit works intermittently during the later stage of heating and mixing.

6. A bamboo-plastic material mixing device comprising the bamboo-plastic material mixing method according to claim 5, characterized in that: Applied to steps S2 and S3, it comprises a cavity (1) for bearing, a plurality of holes for gas passing are arranged around the cavity (1), a bottom blowing plate (2) that can be lifted and lowered is arranged at the bottom end of the cavity (1), a suspension spraying unit (3) is threadedly connected to the top end of the cavity (1), a cover plate (4) for replacing the suspension spraying unit (3) is threadedly connected to the top end of the cavity (1), a gas circulation unit (5) that can exchange the direction of air intake and air exhaust is arranged outside the cavity (1) and communicates with the cavity (1), and a gas heating unit (6) for heating the air intake is jointly connected to the air intake end and the bottom blowing plate (2) in the gas circulation unit (5).

7. The bamboo-plastic material mixing device according to claim 6, wherein: The gas circulation unit (5) comprises a separate gas chamber (501) that communicates with the cavity (1) and is arranged outside the cavity (1), the gas chamber (501) is connected by a connecting pipe (502), the two connecting pipes (502) and an outlet of the gas heating unit (6) and an air exhaust port are connected by an electromagnetic reversing valve (503), and the electromagnetic reversing valve (503) is used for switching the connection of the two connecting pipes (502) and the outlet of the gas heating unit (6). 8.The bamboo-plastic material mixing device according to claim 6, characterized in that: The gas circulating unit (5) comprises a sleeve (504) arranged outside the cavity (1), the sleeve (504) rotates around the cavity (1) under the action of a driving unit (505), the inside of the sleeve (504) is divided into a plurality of air chambers (501) by a partition (507), the air chambers (501) are connected through connecting pipes (502), the outer ring of the cavity (1) is sleeved with two groups of rotating gas supply rings (506), one of the rotating gas supply rings (506) is communicated with the gas heating unit (6). 9.The bamboo-plastic material mixing device of claim 7 or 8, wherein: The device for steps S4 and S5 comprises a shell (7), the inside of the shell (7) is provided with a stirring unit (8), the middle of the shell (7) is provided with a steam discharge unit (9), the upper part of the shell (7) is provided with a coverable feeding port (10), the lower part of the shell (7) is provided with a discharging port (11), the discharging port (11) and the feeding port of the double screw extruder are communicated through a three-way pipe (12) with a closing unit, the inner wall of the shell (7) is provided with a heating unit (13); The steam discharge unit (9) comprises an exhaust hole (901) arranged on the upper wall of the shell (7), and a gas collecting cover (902) wrapped outside the outer ring of the exhaust hole (901), the outer surface of the shell (7) is provided with a covering part (903) for covering the exhaust hole (901) by moving, the covering part (903) leaks the exhaust hole (901) when the stirring unit (8) stops working.

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