Preparation method of polyethylene wax

Abstract

The invention relates to the field of polyethylene wax preparation, and discloses a preparation method of polyethylene wax, in order to solve the problems that in an existing preparation method, energy consumption is high, and the production cost is greatly increased, the preparation method specifically comprises the following steps that S1, raw materials are prepared, high-molecular-weight polyethylene resin, a catalyst and a modifier are prepared, and the modifier is an oxygen-containing monomer; s2, low-temperature catalytic cracking: adopting a continuous low-temperature cracking reactor, and adding a high-molecular-weight polyethylene resin raw material into the reactor; s3, carrying out molecular functional modification; and S4, carrying out post-treatment and purification. According to the preparation method of the polyethylene wax, low-temperature catalytic cracking is carried out at a relatively low temperature, so that the energy consumption and the production cost are reduced, meanwhile, by-products and harmful substances possibly generated by high-temperature cracking are reduced, and by carrying out molecular functional modification and introducing polar groups, the application field of the polyethylene wax is expanded, and the additional value of the polyethylene wax is improved.

Description

Technical Field

[0001] The invention relates to the field of polyethylene wax preparation, and in particular to a method for preparing polyethylene wax. Background Art

[0002] Polyethylene wax is an important additive widely used in the fields of plastics, coatings, inks, etc. In the field of polyethylene wax preparation, traditional technologies have many bottlenecks that are difficult to break through. The traditional method of preparing polyethylene wax by high-temperature cracking often requires a relatively high temperature (generally above 400°C). This process not only consumes a lot of energy, which greatly increases production costs, but also easily produces a large amount of by-products and harmful substances under high temperature conditions, which imposes a heavy burden on the environment. At the same time, due to the single molecular structure and lack of polar groups, traditional polyethylene wax has poor performance in many specific application fields, and its application range is greatly limited;

[0003] In addition, a reaction device is set up in the preparation process of polyethylene wax. The conventional reaction device mixes the materials by stirring to make them uniform, and a heating source is set in the outer jacket of the reaction device to control the reaction temperature. However, due to the limitations of the rotating stirring of the stirring structure, the outer materials are often heated better, while the inner materials are heated poorly, which affects the overall production efficiency.

[0004] Therefore, it is necessary to propose a method for preparing polyethylene wax to solve the above problems. Summary of the invention

[0005] The main purpose of the present invention is to provide a method for preparing polyethylene wax, which can effectively solve the problems in the background technology.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for preparing polyethylene wax comprises the following steps:

[0008] S1: Raw material preparation, high molecular weight polyethylene resin, catalyst and modifier, the modifier is oxygen-containing monomer;

[0009] S2: Low-temperature catalytic cracking, using a continuous low-temperature cracking reactor, adding high molecular weight polyethylene resin raw materials into the reactor, heating to 200-300°C in an air-tight environment, and injecting catalysts at the same time, and finally collecting the cracking products through a condensation system to obtain preliminary polyethylene wax products;

[0010] S3: Molecular functional modification: using a high-pressure reactor, the polyethylene wax collected initially is mixed with oxygen-containing monomers in a certain proportion, added into the high-pressure reactor for stirring, and the temperature is controlled at 150-200°C to carry out copolymerization or grafting reaction to introduce polar groups into the polyethylene wax molecules;

[0011] S4: Post-treatment and purification, using solvent separation or membrane filtration technology to remove unreacted monomers and impurities to obtain pure functionalized polyethylene wax, and then the purified product is passed through a drying device to remove residual solvent to obtain the final product;

[0012] In step S3, the high-pressure reactor includes a shell, a heat equalization mechanism is arranged in the shell, the heat equalization mechanism includes a hollow stirring shaft rotatably connected to the middle of the inner side of the shell, an inner shaft is rotatably connected inside the stirring shaft, the upper end of the stirring shaft extends to the top of the shell, the upper end of the stirring shaft extends to the top of the stirring shaft, and a second bevel gear is fixedly arranged on the outer side of the upper end of the inner shaft, a third bevel gear is fixedly arranged on the outer side of the upper end of the stirring shaft, and a first bevel gear meshing with the second bevel gear and the third bevel gear is arranged on one side between the second bevel gear and the third bevel gear, so that when the first bevel gear rotates, the second bevel gear and the third bevel gear rotate in the opposite direction. The agitator shaft is provided with a driving ring, and the bottom of the inner shaft extends to the bottom of the agitator shaft and is fixed with a second agitator blade extending upward. The upper end of the second agitator blade is fixed with a fixing ring corresponding to the driving ring, and a support is evenly arranged around one side of the fixing ring. A rotating shaft is rotatably connected to the support, and the length direction of the rotating shaft is consistent with the radial direction of the agitator shaft. An end face gear ring is provided on one side of the driving ring, and a gear meshing with the end face gear ring is provided at one end of the rotating shaft. A second agitator blade is provided at the end of the rotating shaft away from the gear.

[0013] Preferably, in step S1, the oxygen-containing monomer is acrylic acid or maleic anhydride;

[0014] The catalyst is a modified Ziegler-Natta catalyst.

[0015] Preferably, the shell is also provided with an adjustment component for changing the direction of the second stirring blade, the adjustment component includes a wavy guide groove arranged on the outer circumference of the driving ring, and the guide groove forms a closed loop on the circumference of the driving ring, a universal joint is provided at the end of the rotating shaft away from the gear, the second stirring blade is arranged at the end of the universal joint away from the rotating shaft, a second bearing is fixedly provided on the outer side of the end of the universal joint close to the second stirring blade, a sliding frame is fixedly provided on the end of the support away from the fixed ring with the driving ring slidingly matched, a slider is longitudinally slidably connected to the sliding frame, a guide wheel is provided on the side of the slider close to the driving ring, and the guide wheel extends to the inner side of the guide groove and cooperates with the movable guide of the guide groove, a traction rod is movably connected to the outer end of the second bearing, and the end of the traction rod away from the second bearing is movably connected to the side of the slider.

[0016] Preferably, a first annular guide rail is provided at one end of the driving ring away from the end gear ring, and one end of the sliding frame away from the support is slidably guided and matched with the first guide rail.

[0017] Preferably, a transversely arranged connecting arm is fixedly provided on a side of the second stirring blade away from the stirring shaft, and a first stirring blade is provided on an end of the connecting arm away from the second stirring blade.

[0018] Preferably, an opening is provided on a side of the first stirring blade away from the stirring shaft, and a scraper matching the shape of the inner wall of the shell is slidably connected to the opening along the radial direction of the stirring shaft.

[0019] Preferably, the upper end of the shell is provided with a pressure driving component for driving the scraper to move radially along the stirring shaft, and the pressure driving component includes a pressure storage cylinder embedded in the outer periphery of the top of the shell, the bottom of the pressure storage cylinder is open, and the top is closed, the inner side of the pressure storage cylinder is vertically slidably connected with a piston plate, an elastic member is provided between the top of the piston plate and the top of the inner cavity of the pressure storage cylinder, and a connecting column is provided at the bottom of the piston plate, and a first bearing is provided at the upper end of the inner side of the shell, and a top frame is fixedly provided on the upper end outer wall of the first bearing, and the top of the top frame is fixedly connected to the bottom of the connecting column, so that the first bearing is driven to move longitudinally when the piston plate is displaced longitudinally, and a bottom frame is fixedly provided on the inner wall of the lower end of the first bearing, and a traction plate corresponding to the first stirring paddle is fixedly provided on the bottom of the bottom frame, the upper end of the scraper is close to the traction plate. The side of the traction plate is movably connected to the inclined surface on the upper end of the scraper, and the inner side of the lower end of the pressure storage cylinder is provided with a piston plate protruding from the inner wall of the pressure storage cylinder and used to block the piston plate.

[0020] Preferably, a second guide rail with an inclination matching that of the inclined surface is provided on the inclined surface at the upper end of the scraper, and the traction plate cooperates with the second guide rail in a sliding guide manner, so that the scraper is displaced radially along the stirring shaft when the traction plate is displaced longitudinally, and is configured so that when the piston plate moves down to the limit distance and contacts the flange, the outer side of the scraper just contacts the inner wall of the shell.

[0021] Preferably, the elastic member is a vertically arranged spring.

[0022] Preferably, an exhaust valve communicating with the inner side of the pressure storage cylinder is provided at the upper end of the pressure storage cylinder.

[0023] Compared with the prior art, the present invention provides a method for preparing polyethylene wax, which has the following beneficial effects:

[0024] 1. The preparation method of polyethylene wax reduces energy consumption and production costs by performing low-temperature catalytic cracking at a relatively low temperature, while reducing by-products and harmful substances that may be generated by high-temperature cracking. By performing molecular functional modification and introducing polar groups, the application field of polyethylene wax is expanded and its added value is increased.

[0025] 2. The method for preparing polyethylene wax is applied to the preparation of polyethylene wax through a specially designed high-pressure reactor, and a heat equalization mechanism arranged in the high-pressure reactor can continuously transport the inner material to the periphery during the reaction, thereby increasing the contact opportunity between the material and the heat source in the outer jacket of the shell, improving the heating uniformity of the reaction material, and thus improving the production efficiency;

[0026] The adjustment components can increase the conveying range when conveying materials, further improving production efficiency, and the structure linkage is compact;

[0027] By setting up a pressure drive component in conjunction with a scraper, the pressure inside the shell can be used to make the scraper contact or separate from the inner wall of the shell. During the reaction, the internal temperature is high and the pressure is high, and the scraper is in a separated state from the inner wall of the shell, reducing wear. After the reaction is completed, the material is reduced, the temperature is lowered, and the internal pressure is lowered during discharge, and the scraper contacts the inner wall of the shell. At this time, the rotation can be controlled to scrape the inner wall of the shell, and the attached residue can be scraped off, reducing the intensity of subsequent cleaning of the inside of the shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the flow chart structure of the preparation method of the present invention;

[0029] Figure 2 It is a structural schematic diagram of the high-pressure reactor of the present invention;

[0030] Figure 3 It is a schematic diagram of the structure of the present invention;

[0031] Figure 4 It is a partial cross-sectional structural schematic diagram of the high-pressure reactor of the present invention;

[0032] Figure 5 The present invention Figure 4 A structural diagram from another perspective based on the above;

[0033] Figure 6 It is a schematic diagram of the structure of the motor, the stirring shaft and the inner shaft of the present invention in a matching state;

[0034] Figure 7 It is a schematic structural diagram of the stirring shaft and the lower end of the inner shaft of the present invention;

[0035] Figure 8 It is a schematic diagram of the structure of the driving ring, the fixing ring and the second stirring blade of the present invention in a coordinated state;

[0036] Fig. 9 The present invention Figure 8 Schematic diagram of the structure when the foundation is disassembled;

[0037] Fig.10 It is a schematic diagram of the structure of the second stirring blade and the sliding frame in the matching state of the present invention;

[0038] Fig.11 The present invention Fig.10 A structural diagram from another perspective based on the above;

[0039] Fig.12 is a schematic diagram of the structure of the pressure drive assembly of the present invention;

[0040] Fig.13 It is a schematic diagram of the structure of the pressure drive assembly of the present invention being disassembled;

[0041] Fig.14 It is a schematic diagram of a partial cross-sectional structure of a pressure storage cylinder of the present invention;

[0042] Fig.15 It is a schematic diagram of the structure of the scraper and the traction plate of the present invention in a connected state;

[0043] Fig.16 It is a schematic diagram of the structure of the first stirring blade and the scraper of the present invention in a separated state.

[0044] In the figure: 1, shell; 2, pressure storage cylinder; 3, first stirring blade; 4, driving ring; 5, fixing ring; 6, first stirring blade; 7, connecting arm; 8, motor; 9, stirring shaft; 10, inner shaft; 11, second stirring blade; 12, traction plate; 13, bottom frame; 14, top frame; 15, first bearing; 16, first bevel gear; 17, second bevel gear; 18, third bevel gear; 19, second stirring blade; 20, end face gear ring; 21, connecting plate; 22, gear; 23, traction rod; 24, support; 25, sliding frame; 26, first guide rail; 27, rotating shaft; 28, universal joint; 29, second bearing; 30, guide groove; 31, exhaust valve; 32, piston plate; 33, elastic member; 34, connecting column; 35, flange; 36, scraper; 37, second guide rail; 38, slider; 39, guide wheel. DETAILED DESCRIPTION

[0045] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0046] like Figure 1 As shown, a method for preparing polyethylene wax comprises the following steps:

[0047] Step 1: Raw material preparation, high molecular weight polyethylene resin or recycled polyethylene waste plastic, catalyst and modifier, select a new low-temperature and high-efficiency catalyst, such as modified Ziegler-Natta catalyst or specific metal oxide catalyst, these catalysts can effectively promote the cracking of polyethylene at a lower temperature, the modifier is an oxygen-containing monomer (such as acrylic acid, maleic anhydride, etc.) for subsequent molecular functionalization modification;

[0048] Step 2: low-temperature catalytic cracking, using a continuous low-temperature cracking reactor equipped with an efficient heat exchange system and a catalyst injection system, adding a high molecular weight polyethylene resin raw material into the reactor, heating it to 200-300°C in an air-tight environment, and injecting a catalyst at the same time, the cracking products are mainly low molecular weight polyethylene wax and a small amount of gaseous by-products, and the final cracking products are collected through a condensation system to obtain a preliminary polyethylene wax product;

[0049] Step 3: Molecular functional modification: using a high-pressure reactor, the polyethylene wax collected initially is mixed with oxygen-containing monomers in a certain proportion, added into the high-pressure reactor for stirring, and the temperature is controlled at 150-200°C to carry out copolymerization or grafting reaction, and polar groups are introduced into the polyethylene wax molecules. By adjusting the reaction time, temperature and pressure, the degree of modification reaction is controlled to obtain the desired functionalized polyethylene wax;

[0050] Step 4: Post-treatment and purification: using solvent separation or membrane filtration technology to remove unreacted monomers and impurities to obtain pure functionalized polyethylene wax. The purified product is then passed through a drying device to remove residual solvent to obtain the final product.

[0051] It should be noted that the modified Ziegler-Natta catalyst is mainly composed of a main catalyst and a co-catalyst. The main catalyst is usually a transition metal halide, such as a halide of titanium, zirconium, vanadium, etc.; the co-catalyst is generally an organic metal compound, such as an alkyl aluminum, etc. This catalyst has extremely high activity and selectivity in olefin polymerization reactions.

[0052] In addition, it has low-temperature high efficiency. In the preparation of polyethylene wax, the modified Ziegler-Natta catalyst can effectively promote the cracking reaction of polyethylene at a lower temperature (such as 200-300°C mentioned in the scheme), which greatly reduces energy consumption and production costs compared to traditional high-temperature cracking methods. At the same time, reacting at a lower temperature can reduce the by-products and harmful substances that may be produced by high-temperature cracking, thereby improving the purity and quality of the product.

[0053] High activity and selectivity, it has high activity in the cracking reaction of polyethylene, can accelerate the reaction process and improve production efficiency;

[0054] It has good selectivity and can control the molecular weight distribution of the cracking products, so that the products are mainly low molecular weight polyethylene wax, meeting specific application requirements;

[0055] Controllability: By modifying the catalyst, its performance can be adjusted to suit different reaction conditions and raw materials. For example, the active center and ligand structure of the catalyst can be changed to adjust the speed of the cracking reaction, the structure and performance of the product, etc.

[0056] Stability: The modified Ziegler-Natta catalyst has good stability during the reaction and can maintain activity for a long time, thereby reducing catalyst loss and replacement frequency and reducing production costs.

[0057] The advantages of the above preparation method compared with the prior art are as follows:

[0058] 1. Low temperature cracking: reduces energy consumption and production costs, while reducing by-products and harmful substances that may be produced by high temperature cracking.

[0059] 2. High-efficiency catalyst: improves cracking efficiency and product purity.

[0060] 3. Molecular functionalization: By introducing polar groups, the application field of polyethylene wax is expanded and its added value is increased.

[0061] 4. Continuous production: Improves production efficiency and is suitable for large-scale industrial production.

[0062] In order to improve the efficiency of introducing polar groups into polyethylene wax molecules, a high-pressure reactor is specially designed:

[0063] like Figure 1-Figure 10 As shown, the high-pressure reactor comprises a shell 1, in which a heat equalization mechanism is arranged, the heat equalization mechanism comprises a stirring shaft 9 which is rotatably connected to the middle of the inner side of the shell 1 and is hollow, an inner shaft 10 is rotatably connected inside the stirring shaft 9, the upper end of the stirring shaft 9 extends to the top of the shell 1, the upper end of the stirring shaft 9 extends to the top of the stirring shaft 9, and a second bevel gear 17 is fixedly arranged on the outer side of the upper end of the inner shaft 10, a third bevel gear 18 is fixedly arranged on the outer side of the upper end of the stirring shaft 9, and a gear 17 which is connected to the third bevel gear 18 is arranged on one side between the second bevel gear 17 and the third bevel gear 18. The first bevel gear 16 is meshed with the second bevel gear 17 and the third bevel gear 18, so that when the first bevel gear 16 rotates, the second bevel gear 17 and the third bevel gear 18 rotate in opposite directions. A motor 8 for driving the first bevel gear 16 to rotate is provided at one end of the top of the shell 1. A driving ring 4 is provided on the outer side of the lower end of the stirring shaft 9. A connecting plate 21 is evenly fixedly provided on the inner wall of the driving ring 4. The other end of the connecting plate 21 is fixed on the outer wall of the stirring shaft 9. The connecting plate 21 not only fixes the driving ring 4 but also serves as a stirring structure to achieve a stirring effect when the stirring shaft 9 rotates. The bottom of the inner shaft 10 extends to the bottom of the stirring shaft 9 and is fixedly provided with a second stirring paddle 11 extending upward. The number of the second stirring paddles 11 is multiple, and the multiple second stirring paddles 11 are evenly surrounded and fixed on the lower end side wall of the inner shaft 10, and the upper end thereof is vertical, which can not only fix the fixing ring 5, but also achieve a stirring effect when the inner shaft 10 rotates. A fixing ring 5 corresponding to the driving ring 4 is fixedly provided on the upper end of the second stirring paddle 11. One side of the fixing ring 5 is evenly surrounded by a A support 24 is provided, and a rotating shaft 27 is rotatably connected to the support 24, and the length direction of the rotating shaft 27 is consistent with the radial direction of the stirring shaft 9. An end face gear ring 20 is provided on one side of the driving ring 4. There are two driving rings 4, and the end face gear rings 20 are respectively provided on the opposite sides of the two driving rings 4. There are two fixed rings 5, and the two fixed rings 5 ​​are located between the two driving rings 4. One end of the rotating shaft 27 is provided with a gear 22 meshing with the end face gear ring 20, and the end of the rotating shaft 27 away from the gear 22 is provided with a second stirring blade 19;

[0064] Furthermore, the housing 1 is also provided with an adjustment component for changing the direction of the second stirring blade 19, the adjustment component includes a wave-shaped guide groove 30 arranged on the outer circumference of the driving ring 4, and the guide groove 30 forms a closed loop on the circumference of the driving ring 4, a universal joint 28 is arranged at one end of the rotating shaft 27 away from the gear 22, the second stirring blade 19 is arranged at one end of the universal joint 28 away from the rotating shaft 27, a second bearing 29 is fixedly arranged on the outer side of one end of the universal joint 28 close to the second stirring blade 19, and a bearing 29 is fixedly arranged on one end of the support 24 away from the fixing ring 5, which is slidable with the driving ring 4. A sliding frame 25 is movably matched, and a first annular guide rail 26 is provided at one end of the driving ring 4 away from the end face gear ring 20. The end of the sliding frame 25 away from the support 24 is slidably guided and matched with the first guide rail 26. A slider 38 is longitudinally slidably connected to the sliding frame 25. A guide wheel 39 is provided on the side of the slider 38 close to the driving ring 4, and the guide wheel 39 extends to the inner side of the guide groove 30 and movably guides and matches with the guide groove 30. A traction rod 23 is movably connected to one end of the outer side of the second bearing 29, and the end of the traction rod 23 away from the second bearing 29 is movably connected to the side of the slider 38.

[0065] In addition, if Figure 2-Figure 6 As shown, in order to further improve the stirring effect, a first stirring blade 6 is provided at the bottom of the inner shaft 10 for stirring the bottom area of ​​the inner cavity of the shell 1;

[0066] like Figure 2-Figure 5 , Figure 14-15 As shown, in order to further improve the stirring effect, a transversely arranged connecting arm 7 is fixedly arranged on one side of the second stirring blade 11 away from the stirring shaft 9, and a first stirring blade 3 is arranged on one end of the connecting arm 7 away from the second stirring blade 11. The first stirring blade 3 is evenly arranged around the periphery of the inner side of the housing 1;

[0067] Further, such as Figure 1-Figure 4 , Figure 11-Figure 15As shown, since there is easily residue on the inner wall of the shell 1 after discharging, in order to clean the inner wall of the shell 1, an opening is provided on the side of the first stirring blade 3 away from the stirring shaft 9, and a scraper 36 adapted to the shape of the inner wall of the shell 1 is slidably connected in the radial direction of the stirring shaft 9 in the opening, and a pressure driving component for driving the scraper 36 to move radially along the stirring shaft 9 is provided at the upper end of the shell 1, and the pressure driving component includes a pressure storage cylinder 2 embedded in the outer periphery of the top of the shell 1, the bottom of the pressure storage cylinder 2 is open, and the top is closed, and a piston plate 32 is vertically slidably connected to the inside of the pressure storage cylinder 2, and an elastic member 33 is provided between the top of the piston plate 32 and the top of the inner cavity of the pressure storage cylinder 2, and the elastic member 33 is a vertically arranged spring or other elastic structure, and a connecting column 34 is provided at the bottom of the piston plate 32, and a first bearing 15 is provided at the upper end of the inner side of the shell 1, and a top frame 14 is fixedly provided on the outer wall of the upper end of the first bearing 15, and the top frame 1 The top of the connecting column 34 is fixedly connected to the bottom of the connecting column 34, so that the piston plate 32 drives the first bearing 15 to move longitudinally when the piston plate 32 is displaced longitudinally. The bottom inner wall of the lower end of the first bearing 15 is fixedly provided with a base frame 13, and the bottom of the base frame 13 is fixedly provided with a traction plate 12 corresponding to the first stirring blade 3. The upper end of the scraper 36 is close to the traction plate 12. The side of the traction plate 12 corresponds to the slant surface of the upper end of the scraper 36. The inner side of the lower end of the pressure storage cylinder 2 is provided with a flange 35 protruding from the inner wall of the pressure storage cylinder 2 and used to block the piston plate 32. The upper end of the scraper 36 is provided with a second guide rail 37 with an inclination adapted to the slant surface. The traction plate 12 is slidably guided and matched with the second guide rail 37, so that the scraper 36 is displaced along the radial direction of the stirring shaft 9 when the traction plate 12 is displaced longitudinally, and is configured so that when the piston plate 32 moves down to the limit distance and contacts the flange 35, the outer side of the scraper 36 just contacts the inner wall of the shell 1.

[0068] In addition, in order to accommodate the gas entering and exiting the pressure storage cylinder 2 when the piston plate 32 is longitudinally displaced, an exhaust valve 31 communicating with the inner side of the pressure storage cylinder 2 is provided at the upper end of the pressure storage cylinder 2 .

[0069] It should be noted that the high-pressure reactor and its internal structure are usually made of high-strength, corrosion-resistant materials, such as carbon steel, stainless steel or alloy steel, and are also provided with a heating structure, which is preferably a jacket for heating to control the reaction temperature. The heating system can usually adjust parameters such as the heating speed and the heating temperature to ensure that the reaction is carried out within the desired temperature range;

[0070] It is also equipped with components such as pressure sensors and pressure regulating valves to monitor and control the working pressure of the high-pressure reactor. The pressure control system can automatically adjust the reaction pressure to achieve the required reaction conditions while ensuring the safe operation of the equipment.

[0071] Also includes some necessary safety equipment:

[0072] Including but not limited to explosion-proof speed regulators, pressure relief valves, temperature alarm systems, etc., which are used to take timely measures when equipment abnormalities occur to ensure the safety of personnel and equipment.

[0073] Other accessories:

[0074] Components such as solid feed port and discharge valve provide convenience for the operation and maintenance of the high-pressure reactor.

[0075] As for the specific working principle of the high-pressure reactor, when the material is added for stirring during use, the control motor 8 drives the first bevel gear 16 to rotate, and the first bevel gear 16 realizes the coaxial reversal of the inner shaft 10 and the stirring shaft 9 through the second bevel gear 17 and the third bevel gear 18. The stirring shaft 9 drives the driving ring 4 to rotate, and the connecting plate 21 can perform a certain degree of stirring. The inner shaft 10 drives the first stirring blade 6, the second stirring blade plate 11, the fixing ring 5, the connecting arm 7, and the first stirring blade plate 3 to rotate, and the connecting arm 7, the first stirring blade plate 3, the first stirring blade 6, and the second stirring blade plate 11 can achieve a stirring effect. In reverse rotation, the driving ring 4 and the fixed ring 5 rotate relative to each other, and then the end face gear ring 20 realizes the vibration of the gear 22. The gear 22 drives the second stirring blade 19 to rotate through the second zone and the universal joint 28. The second stirring blade 19 realizes the transportation of materials and improves the uniformity of heating. Moreover, when the fixed ring 5 and the driving ring 4 rotate relative to each other, the sliding frame 25 will slide relative to the driving ring 4. Under the action of the guide groove 30, the guide wheel 39 continuously rises and falls, thereby driving the slider 38 to move longitudinally. The slider 38 drives the second stirring blade 19 to change direction continuously through the traction rod 23, thereby realizing the transportation of materials in different directions;

[0076] In addition, since there is a certain pressure and temperature inside the shell 1 during the reaction, the internal pressure is relatively high, and the pressure will push the piston plate 32 upward. The piston plate 32 compresses the elastic member 33, and the internal gas is discharged through the exhaust valve 31. The piston plate 32 drives the top frame 14, the first bearing 15, the bottom frame 13, and the traction plate 12 to move upward as a whole through the connecting column 34. The traction plate 12 drives the scraper 36 to move toward the inside of the first stirring blade 3 through the action of the second guide rail 37. At this time, the scraper 36 does not contact the inner wall of the shell 1, which can reduce wear. When the reaction is completed and the material is discharged, the internal material is reduced. And the temperature will gradually decrease, and then the internal pressure of the shell 1 will decrease, the elastic member 33 will reset, the piston plate 32 will move down, and then the bottom frame 13, the top frame 14, the first bearing 15, and the traction plate 12 will move down as a whole, and then the scraper 36 will gradually move toward the inner wall of the shell 1. When the piston plate 32 contacts the flange 35, the piston plate 32 reaches the limit distance. At this time, the scraper 36 contacts the inner wall of the shell 1, and then the stirring shaft 9 continues to rotate to drive the first stirring blade 3 to rotate. The scraper 36 scrapes the inner wall of the shell 1 to scrape off impurities such as residues on the inner wall, which can reduce the time and difficulty of subsequent cleaning of the inside of the shell 1.

[0077] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for preparing polyethylene wax, characterized in that: The following steps are involved: S1: Raw material preparation, high molecular weight polyethylene resin, catalyst and modifier, the modifier is oxygen-containing monomer; S2: Low-temperature catalytic cracking, using a continuous low-temperature cracking reactor, adding high molecular weight polyethylene resin raw materials into the reactor, heating to 200-300°C in an air-tight environment, and injecting catalysts at the same time, and finally collecting the cracking products through a condensation system to obtain preliminary polyethylene wax products; S3: Molecular functional modification: using a high-pressure reactor, the polyethylene wax collected initially is mixed with oxygen-containing monomers in a certain proportion, added into the high-pressure reactor for stirring, and the temperature is controlled at 150-200°C to carry out copolymerization or grafting reaction to introduce polar groups into the polyethylene wax molecules; S4: Post-treatment and purification, using solvent separation or membrane filtration technology to remove unreacted monomers and impurities to obtain pure functionalized polyethylene wax, and then the purified product is passed through a drying device to remove residual solvent to obtain the final product; In step S3, the high-pressure reactor comprises a shell (1), wherein a heat equalization mechanism is arranged in the shell (1), wherein the heat equalization mechanism comprises a hollow stirring shaft (9) rotatably connected to the middle part of the inner side of the shell (1), wherein an inner shaft (10) is rotatably connected inside the stirring shaft (9), wherein the upper end of the stirring shaft (9) extends to the top of the shell (1), wherein the upper end of the stirring shaft (9) extends to the top of the stirring shaft (9), and a second bevel gear (17) is fixedly arranged on the outer side of the upper end of the inner shaft (10), and a third bevel gear (18) is fixedly arranged on the outer side of the upper end of the stirring shaft (9), and a first bevel gear (16) meshing with the second bevel gear (17) and the third bevel gear (18) is arranged on one side between the second bevel gear (17) and the third bevel gear (18), so that when the first bevel gear (16) rotates, the second bevel gear (17) and the third bevel gear (18) rotate in opposite directions, and the shell (1) A motor (8) for driving the first bevel gear (16) to rotate is arranged at one end of the top, a driving ring (4) is fixed on the outer wall of the lower end of the stirring shaft (9), the bottom of the inner shaft (10) extends to the bottom of the stirring shaft (9) and is fixedly provided with a second stirring blade (11) extending upward, the upper end of the second stirring blade (11) is fixedly provided with a fixing ring (5) corresponding to the driving ring (4), a support (24) is evenly arranged around one side of the fixing ring (5), a rotating shaft (27) is rotatably connected to the support (24), and the length direction of the rotating shaft (27) is consistent with the radial direction of the stirring shaft (9), an end face gear ring (20) is arranged on one side of the driving ring (4), a gear (22) meshing with the end face gear ring (20) is arranged at one end of the rotating shaft (27), and a second stirring blade (19) is arranged at the end of the rotating shaft (27) away from the gear (22).

2. The method for preparing polyethylene wax according to claim 1, wherein: In step S1, the oxygen-containing monomer is acrylic acid or maleic anhydride; The catalyst is a modified Ziegler-Natta catalyst.

3. The method for preparing polyethylene wax according to claim 1, characterized in that: The housing (1) is also provided with an adjustment component for changing the direction of the second stirring blade (19), the adjustment component comprising a wave-shaped guide groove (30) arranged on the outer circumference of the driving ring (4), and the guide groove (30) forms a closed loop on the circumference of the driving ring (4), a universal joint (28) is arranged at one end of the rotating shaft (27) away from the gear (22), the second stirring blade (19) is arranged at one end of the universal joint (28) away from the rotating shaft (27), and a second bearing (29) is fixedly arranged on the outer side of one end of the universal joint (28) close to the second stirring blade (19), A sliding frame (25) which is slidably matched with the driving ring (4) is fixedly provided at one end of the support (24) away from the fixed ring (5); a slider (38) is longitudinally slidably connected to the sliding frame (25); a guide wheel (39) is provided on the side of the slider (38) close to the driving ring (4); the guide wheel (39) extends to the inner side of the guide groove (30) and is movably guided and matched with the guide groove (30); a traction rod (23) is movably connected to one end of the outer side of the second bearing (29); and one end of the traction rod (23) which is away from the second bearing (29) is movably connected to the side of the slider (38).

4. The method for preparing polyethylene wax according to claim 3, characterized in that: An end of the drive ring (4) away from the end face gear ring (20) is provided with a first guide rail (26) in an annular shape, and an end of the sliding frame (25) away from the support (24) is slidably guided and matched with the first guide rail (26).

5. The method for preparing polyethylene wax according to claim 1, characterized in that: A transversely arranged connecting arm (7) is fixedly arranged on one side of the second stirring blade (11) away from the stirring shaft (9), and a first stirring blade (3) is arranged on one end of the connecting arm (7) away from the second stirring blade (11).

6. The method for preparing polyethylene wax according to claim 5, characterized in that: An opening is provided on a side of the first stirring blade (3) away from the stirring shaft (9), and a scraper (36) matching the shape of the inner wall of the shell (1) is slidably connected in the opening along the radial direction of the stirring shaft (9).

7. The method for preparing polyethylene wax according to claim 6, characterized in that: The upper end of the shell (1) is provided with a pressure drive assembly for driving the scraper (36) to move radially along the stirring shaft (9), and the pressure drive assembly includes a pressure storage cylinder (2) embedded in the outer periphery of the top of the shell (1), the bottom of the pressure storage cylinder (2) is open, and the top is closed, the inner side of the pressure storage cylinder (2) is vertically slidably connected with a piston plate (32), an elastic member (33) is provided between the top of the piston plate (32) and the top of the inner cavity of the pressure storage cylinder (2), and a connecting column (34) is provided at the bottom of the piston plate (32), and a first bearing (15) is provided at the upper end of the inner side of the shell (1), and a top frame (14) is fixedly provided on the outer wall of the upper end of the first bearing (15). ), and the top of the top frame (14) is fixedly connected to the bottom of the connecting column (34), so that when the piston plate (32) is displaced longitudinally, the first bearing (15) is driven to be displaced longitudinally, the lower inner wall of the first bearing (15) is fixedly provided with a bottom frame (13), and the bottom of the bottom frame (13) is fixedly provided with a traction plate (12) corresponding to the first stirring blade (3), the upper end of the scraper (36) is close to the traction plate (12) The side is an inclined surface, and the lower end of the traction plate (12) is movably connected to the inclined surface of the upper end of the scraper (36), and the inner side of the lower end of the pressure storage cylinder (2) is provided with a piston plate (32) protruding from the inner wall of the pressure storage cylinder (2) and used to block the piston plate (32).

8. The method for preparing polyethylene wax according to claim 7, characterized in that: A second guide rail (37) having an inclination matching that of the inclined surface is arranged on the inclined surface at the upper end of the scraper (36), and the traction plate (12) is slidably guided in cooperation with the second guide rail (37), so that when the traction plate (12) is longitudinally displaced, the scraper (36) is radially displaced along the stirring shaft (9), and is configured such that when the piston plate (32) moves down to a limit distance and contacts the flange (35), the outer side of the scraper (36) just contacts the inner wall of the housing (1).

9. The method for preparing polyethylene wax according to claim 7, characterized in that: The elastic member (33) is a vertically arranged spring.

10. The method for preparing polyethylene wax according to claim 7, characterized in that: The upper end of the pressure storage cylinder (2) is provided with an exhaust valve (31) which is in communication with the inner side of the pressure storage cylinder (2).

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