Waxes as melt flow modifiers and processing aids for polymers

Abstract

An improved method for forming and employing wax to modify polymer yield and melt flow. The method includes: (a) selecting a solid polymer material; (b) heating the solid polymer material in an extruder to produce a molten polymer material; (c) filtering the molten polymer material; (d) placing the molten polymer material in a reactor via a chemical depolymerization process to produce a depolymerized polymer material; and (e) adding the depolymerized material to a prewax mixture to produce a modified polymer.

Description

[0001] This application is a divisional application of the invention application filed on March 24, 2017, with international application number PCT / CA2017 / 050378, Chinese national phase application number 201780018293.8, and entitled "Wax as a melt flow modifier and processing aid for polymers".

[0002] Cross-references to related applications

[0003] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 312,899, filed March 24, 2016, entitled “Wax as a Melt Flow Modifier and Processing Aid for Polymers.” Application '899 is incorporated herein by reference in its entirety. Technical Field

[0004] This invention relates to a method for producing synthetic wax from plastic materials and using the wax to modify virgin plastics during the processing stage. Specifically, virgin or recycled polyethylene plastics can be modified with wax to alter their processing yield and physical properties such as melt flow index. Increased yield improves operating efficiency and reduces manufacturing costs. The addition of wax, which affects yield, is also associated with reduced extruder back pressure, meaning less equipment wear. Changes in physical properties, including improved polymer flow or viscosity, are beneficial in a variety of fields, including injection molding, blow molding, rotational molding, compression molding, casting, calendering, blending, grinding, and granulation. Background Technology

[0005] Additives are common in polymer processing. However, the use of polyethylene wax to improve polyethylene yield, physical properties, and processability is not widely adopted, especially in recycled streams. Typical limiting factors include high cost and poor blending of polyethylene wax and polymer.

[0006] Significant efforts have recently been made to convert polymer solid waste into useful products. However, existing conversion processes are inefficient and can release greenhouse gases into the environment.

[0007] There is a need for a low-cost method for producing waxes that can be used to achieve improved processing and more desirable physical properties of specific polymers, while ensuring good blending of polyethylene polymers and polyethylene wax additives. Such a method would ideally utilize readily available, inexpensive raw materials (preferably renewable materials) and employ an economical process. Summary of the Invention

[0008] A method for forming a wax and using the wax to modify polymer processing and material properties includes: selecting a solid polymer material; heating the solid polymer material in an extruder to produce a molten polymer material; filtering the molten polymer material; placing the molten polymer material in a reactor via a chemical depolymerization process to produce a depolymerized wax material; adding the depolymerized wax material to a pre-wax mixture to produce a modified polymer with an increased melt flow index; filtering the solid polymer material; cooling the depolymerized polymer material; purifying the depolymerized polymer material; and / or using gases and oils generated during the purification of the depolymerized polymer material as fuel for at least one step of the method.

[0009] In some implementations, the method is continuous or semi-continuous.

[0010] In some embodiments, the polymer material is one or more of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and polypropylene. In some embodiments, the polymer material and / or pre-waxed mixture contains recycled plastics.

[0011] In some embodiments, a purification step is not required, or the purification step employs one of flash separation, absorption bed, clay polishing, and thin-film evaporation. In some embodiments, the depolymerized material is added to the prewax mixture via an in-line pump. In some embodiments, the filtration step employs a screen changer and / or a filter bed.

[0012] In some embodiments, the depolymerization process employs a catalyst and / or a second reactor. In some embodiments, the catalyst is supported on zeolite and / or alumina. In some embodiments, the reactors are connected in series. In some embodiments, the reactors are vertically stacked. In some embodiments, the reactor includes a static mixer.

[0013] In some implementations, the prewax mixture contains a solid polymer material. Attached Figure Description

[0014] Figure 1 This is a flowchart illustrating a method for producing wax and using it as a melt flow modifier in a polymer.

[0015] Figure 2 This is a schematic diagram of a system for producing wax from plastic raw materials.

[0016] Figure 3 This is a cross-sectional side view of a catalytic reactor having a removable static mixer configured to be heated via a hot fluid / molten salt.

[0017] Figure 4 It is a set of parallel arrangements Figure 3 A cross-sectional front view of a catalytic reactor of the type shown.

[0018] Figure 5 It is shown in a horizontal structure. Figure 4 A cross-sectional side view of the parallel catalytic reactor arrangement.

[0019] Figure 6 It is a cross-sectional side view of a vertical spiral internal catalytic reactor arrangement with two reactors connected in series.

[0020] Figure 7 This is a three-dimensional view of a horizontal reactor with an internal spiral mixer.

[0021] Figure 8 This is a graph showing the reduction in the amount of pressure required to push a wax-modified polymer material through an extruder compared to an unmodified polymer material. Detailed Implementation

[0022] The process of converting polymeric materials, such as waste polymeric materials, into waxes is described below. These waxes can then be used to modify polymers. The waxes are compatible with a variety of polymeric material additives and can be combined with a variety of materials commonly used to improve polymer quality.

[0023] In some implementations, the addition of wax improves the processing characteristics of the polymer blend, including improving the lubrication of the extruder or processing equipment that melts the blend, and increasing the extruder's kilogram-hour production capacity.

[0024] In other or similar embodiments, the addition of wax improves the physical properties of the final product. The resulting final product can have a variety of properties different from its unmodified form. In some embodiments, these properties include, in particular, a change in its melt flow index (MFI), which in turn alters the viscosity of the polymer and, when the polymer is in liquid form, results in a change in flow rate.

[0025] Some implementations involve at least two main concepts: (1) producing a synthetic wax via the depolymerization of a plastic, and then (2) adding this wax to modify another plastic. In some implementations, the plastic raw material used to produce the synthetic wax is the same as the raw material used to produce the final product plastic.

[0026] Figure 1A process 600 for producing synthetic waxes and then using those waxes to modify polymers is illustrated. Process 600 can be performed in batches, but is more preferably a continuous process. Parameters of process 600 can be varied to produce final products with different molecular weights and structural properties, including but not limited to temperature, plastic flow rate, and the total number of preheating, reaction, or cooling sections. For example, increasing the temperature and / or decreasing the flow rate throughout the wax production stage 2000 will yield waxes with lower molecular weights. The wax production stage 2000 allows for precise targeting of specific wax properties, such as those that maximize the desired blending effect.

[0027] In material selection phase 1, a polymer feed is selected and / or prepared for processing. In some embodiments, the polymer feed is sorted / selected to include polyethylene material. The polymer may be HDPE, LDPE, LLDPE, and / or other polyethylene variants.

[0028] In other embodiments, the polymer feed is sorted / selected to include polypropylene material. In other embodiments, the polymer feed is sorted / selected to include both polyethylene and polypropylene material. In some embodiments, the feed may contain up to 20% polypropylene, lower amounts of polystyrene, PET, EVA, PVC, EVOH, and undesirable additives and / or contaminants such as fillers, dyes, metals, various organic and inorganic additives, moisture, food waste, dirt, or other contaminating particles.

[0029] In some embodiments, the materials selected in material selection phase 1 include recycled plastics. In other or similar embodiments, the materials selected in material selection phase 1 include recycled plastics and / or virgin plastics.

[0030] The polymer feed used in material selection stage 1 can be from plastic feed A1 or plastic feed A2. When the feed is from plastic feed A2, the resulting wax can have a similar composition when more plastic is added from plastic feed A2 to produce the final plastic E. This results in a more homogeneous product with improved yield and melt flow modification.

[0031] In some embodiments, the material selected in material selection stage 1 is heated in the extruder in heating stage 2 and undergoes a pre-filtration process 3. In some embodiments, the extruder is used to increase the temperature and / or pressure of the incoming plastic, and / or to control the flow rate of the plastic. In some embodiments, the extruder is supplemented with a pump / heat exchanger combination or is completely replaced by a pump / heat exchanger combination.

[0032] The pre-filtration process 3 may employ both a filter changer and / or a filter bed, along with other filtration technologies / devices, to remove contaminants from the heated material and purify the heated material. The resulting filtered material is then transferred to an optional preheating stage 4, which allows the filtered material to reach a higher temperature before entering the depolymerization stage 5. Among other devices and technologies, the preheating stage 4 may employ a static mixer and / or heat exchanger such as internal fins and / or heat pipes.

[0033] In depolymerization stage 5, the materials undergo depolymerization. This depolymerization can be a purely thermal reaction, or it can be carried out using a catalyst. Depending on the starting materials and the desired end product, depolymerization can be used to slightly or drastically reduce the molecular weight of the starting materials.

[0034] In some embodiments, the catalyst used is a zeolite or alumina-supported system or a combination of both. In some embodiments, the zeolite contains alumina. In some embodiments, the catalyst is prepared by combining a ferrous-copper complex with an alumina or zeolite support and reacting it with an inorganic acid.

[0035] The depolymerization stage 5 can employ a variety of technologies / apparatus, particularly including horizontal and / or vertical fixed-bed reactors and / or static mixers. In some embodiments, the reaction stage 5 employs multiple reactors and / or reactors divided into multiple sections to produce a semi-continuous or continuous process.

[0036] After depolymerization stage 5, the depolymerized material either enters cooling stage 6 or is directly pumped to extruder 9 via pipeline pump 8, where it is mixed with plastic from plastic feed A2 to produce final plastic E.

[0037] Cooling stage 6 may employ heat exchangers and other technologies / devices to reduce the depolymerized material to a working temperature before it enters optional purification stage 7 or before it is pumped via pipeline pump 8 and mixed with plastic from plastic feed A2 to produce final plastic E.

[0038] In some implementations, the cleaning / purification of materials occurs before cooling stage 6, using methods such as nitrogen stripping.

[0039] Purification stage 7 involves the refining and / or purification of the depolymerized material. Techniques / apparatus that may be used in purification stage 7 include, but are not limited to, flash separation, absorption bed, clay polishing, distillation, vacuum distillation and / or filtration to remove solvents, oils, color bodies, ash, inorganic matter and / or coke.

[0040] In some embodiments, a thin-film or scraped-film evaporator is used to remove gases, oils, and / or greases from the depolymerized material. In some embodiments, the oils, gases, and greases can then be combusted to aid in the operation of various stages of process 2000.

[0041] In some embodiments, the purified material is pumped directly into the extruder 9 via a pipeline pump 8, where it is mixed with plastic from plastic feed A2 to produce the final plastic E. In other embodiments, the purified material is processed into a solid wax C, which can then be used as wax feed B in the plastic modification stage 3000.

[0042] The wax production stage 2000 ends at wax C, where the initial starting material selected in material selection stage 1 has been transformed into wax C. In at least some embodiments, wax C is included as part of the wax feed B. In some embodiments, wax C is not highly branched, but has a more linear structure.

[0043] The plastic modification stage 3000 involves combining plastic from plastic feed A2 with synthetic wax. In some embodiments, the synthetic wax is taken from wax feed B and mixed with plastic from plastic feed A2 to form plastic / wax feed D, which is then fed to extruder 9 before becoming the final plastic E. In some embodiments, the wax in wax feed B is produced via wax production stage 2000. In some embodiments, the percentage of wax in the wax / plastic compound is approximately 1-8%.

[0044] In other embodiments, plastic from plastic feed A2 is directly mixed with hot wax from wax generation stage 2000. This method makes it possible to eliminate several steps in the process, such as cooling the wax (cooling stage 6) and / or transporting the wax from one location to another.

[0045] Reference Figure 2 System 1000 includes a reactor 700 having five reactor modules 102(a) to 102(e). The dimensions of the reactor modules 102 can vary, and / or the reactor modules 102 can be connected in parallel and / or in series. In other embodiments, various numbers of reactor modules 102 can be employed. The ability to customize the number of reactor modules 102 allows for greater control over the amount of depolymerization. System 1000 is typically used in the wax production stage 2000.

[0046] System 1000 may include a hopper 111 for receiving polymer material and / or directing a supply of polymer material to an optional extruder 106. In some embodiments, the extruder 106 processes the polymer material received from the hopper 111 by producing molten polymer material. The temperature of the polymer material processed by the extruder 106 is controlled by adjusting the level of shear and / or heat applied to the polymer material by one or more extruder heaters 105. The extruder heaters may use various heat sources, including but not limited to electricity, hot fluids, and / or combustion gases. The heat can be adjusted by a controller in response to the temperature sensed by one or more temperature sensors 107.

[0047] In some embodiments, pressure sensor 109 measures the pressure of the molten polymer material discharged from extruder 106 to prevent or at least reduce the risk of pressure spikes. The discharged molten polymer material can be pressurized by pump 110 to facilitate its flow through heating zone 108 and reactor 100. As it flows through reactor 100, the molten polymer material processed in the reactor can come into contact with the catalyst material that causes depolymerization.

[0048] One or more pressure sensors 109 and / or one or more temperature sensors 107 may also be used to measure the temperature and / or pressure of the molten polymer material being processed in the reactor as it flows through reactor 100. One or more pressure sensors 109 may monitor the plugs before and / or after each reaction zone. One or more pressure sensors 109 may also maintain the system pressure below the maximum pressure (such as the maximum pressure designed for reactor 700). Overpressure can be controlled via feedback from the pressure transmitter 109 to a controller that sends a command signal to shut down extruder 106 and pump 110, thereby preventing further pressure increases.

[0049] If shutting down the extruder 106 fails to release overpressure, the discharge valve 117 can be opened into the container to remove material from the system 1000 and prevent overpressure. During shutdown, the discharge valve 117 can be opened to purge the system 1000 with nitrogen to remove any remaining material, thus preventing material blockage and degradation during the next startup.

[0050] System 1000 may also include a pressure reducing device, such as a pressure reducing valve or a rupture disc, located at the outlet of extruder 106 to release pressure from system 1000 in the event of overpressure.

[0051] One or more temperature sensors 107 can facilitate the control of the temperature of the molten polymer material flowing through reactor 100. This allows for more precise control of the chemical reaction and the resulting polymerization. One or more temperature sensors 107 also help maintain the temperature below a predetermined maximum temperature (e.g., the maximum design temperature of reactor 100).

[0052] In response to temperature sensing by one or more temperature sensors 119, the temperature is controlled by a controller (not shown) that regulates the heat applied by heaters 118 which are configured to be in heat transfer communication with reaction zones 102(a) to 102(e) of reactor 100.

[0053] System 1000 may also include a pressure reducing device, such as a pressure reducing valve or a rupture disc, located at the outlet of extruder 106 to release pressure from system 10 in the event of overpressure.

[0054] Flow control can also be provided within system 1000. In some embodiments, system 1000 includes a valve 115 located at the outlet of extruder 106 for controlling the flow from extruder 106 to other unit operations within system 1000. Valve 116 facilitates recirculation. Valve 117 enables product collection.

[0055] During operation, valve 115 can be closed to recirculate the molten polymer material and raise its temperature to the desired level. In this case, valve 116 will open, valve 117 will close, extruder 106 will be shut down, and pump 110 will recirculate.

[0056] The resulting molten product material 112 is cooled in a heat exchanger 114, which may be water-jacketed, air-cooled, and / or refrigerant-cooled, among other things. A portion of the cooled resulting molten product material may be recycled (in which case valve 116 will open) for reprocessing and / or for energy saving.

[0057] In some implementations, system 1000 is configured to purge with nitrogen to reduce oxidation of the molten products.

[0058] In system 1000, reactor 700 includes one or more reactor modules. Each reactor module includes a corresponding module reaction zone in which molten polymer material being processed by the reactor is contacted with a catalyst material for a module-defined residence time, thereby causing depolymerization of the flowing molten polymer material being processed by the reactor. In some of these embodiments, at least two of the reactor modules have the same or substantially the same residence time. In some of these embodiments, at least some of the multiple modules have different residence times. In some embodiments, at least two of the catalyst materials in the reactor modules are the same or substantially the same. In other embodiments, at least two of the reactor modules have different catalyst materials.

[0059] In some embodiments, each reactor module includes a container permeable to the molten polymer material being processed by the reactor, the container containing a catalyst material. The container may be configured to receive the molten polymer material such that at least a portion of the received molten polymer material undergoes at least partial depolymerization under the influence of the catalyst material, and to discharge a molten product material comprising depolymerization reaction products (and may contain unreacted molten polymer material and intermediate reaction products, or both). The flow of the reactor-processed molten polymer material through the permeable container affects the contact between the catalyst material and the reactor-processed molten polymer material to influence at least a portion of the reactor-processed molten polymer material undergoing at least partial depolymerization. In this respect, the flowing reactor-processed molten polymer material permeates through the catalyst material within the container and, while permeating through the catalyst material, contacts the catalyst material contained within the container to influence at least a portion of the reactor-processed molten polymer material undergoing at least partial depolymerization.

[0060] In system 1000, the first reactor is assembled from reactor modules. The first reactor has a first reaction zone and includes a total of "P" reactor modules from "N" reactor modules, where "N" is an integer greater than or equal to 1.

[0061] Each of the “N” reactor modules defines a corresponding modular reaction zone containing catalyst material disposed therein, and is configured to guide the flow of molten polymer material being processed by the reactor through the corresponding modular reaction zone, such that the flow of the molten polymer material being processed by the reactor through the corresponding modular reaction zone brings it into contact with the catalyst material, thereby causing at least partial depolymerization of at least a portion of the flowing molten polymer material being processed by the reactor. In this respect, the first reaction zone comprises “P” modular reaction zones.

[0062] When "N" is an integer greater than or equal to 2, each of the "N" reactor modules is configured to be connected in series with one or more other "N" reactor modules, such that the multiple reactor modules are connected in series with each other, and includes multiple module reaction zones arranged in series in fluid communication with each other, such that the total number of module reaction zones corresponds to the total number of connected reactor modules. The multiple connected reactor modules are configured to guide the flow of molten polymer material being processed by the reactor through the multiple module reaction zones, such that it comes into contact with catalyst material, thereby affecting at least a portion of the flowing molten polymer material being processed by the reactor through at least partial depolymerization.

[0063] When “P” is an integer greater than or equal to 2, the assembly of the first reactor includes connecting “P” reactor modules in series with each other, such that “P” reaction zones are configured to be fluidly connected in series with each other.

[0064] exist Figure 2 In the illustrated embodiment, "P" equals 5, such that reactor 700 comprises five reactor modules 102(a) to 102(e), and the reaction zone consists of five modular reaction zones 104(a) to 104(e), each modular reaction zone corresponding to one of the five reactor modules. "P" can be greater than or less than 5.

[0065] By heating the polymer material, molten polymer material is produced for supplying to the constructed reactor. In some embodiments, heating is performed using a heater. Figure 2 In this embodiment, heating is generated by a combination of an extruder 106 and a separate heater 108. In such an embodiment, the resulting molten polymer material is forced from the extruder through the separate heater and then supplied to the modular reaction zone. In some embodiments, the extruder is configured to provide sufficient heat to the polymer material, such that the resulting molten polymer material is at a sufficiently high temperature to be supplied to the reactor, and a separate heater is not required.

[0066] exist Figure 2 In this process, pump 110 receives molten polymer material from extruder 106 and influences the transport (or flow) of the molten polymer material through heater 108 and then through the first reaction zone. In some embodiments, extruder 106 is configured to impart sufficient force to influence the desired flow of the resulting molten polymer material, making pump 110 optional.

[0067] In some embodiments, the molten polymer material originates from a polymer material feed that is heated to influence the formation of the molten polymer material. In some embodiments, the polymer material feed comprises primary raw polyethylene pellets. The raw pellets may comprise low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), polypropylene (PP), or a mixture comprising a combination of LDPE, LLDPE, HDPE, and PP.

[0068] In some embodiments, the polymer material feed includes waste polymer material feed. Suitable waste polymer material feeds include mixed polyethylene waste, mixed polypropylene waste, and mixtures comprising mixed polyethylene waste and mixed polypropylene waste. Mixed polyethylene waste may include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), polypropylene (PP), or mixtures comprising a combination of LDPE, LLDPE, HDPE, and PP. In some embodiments, mixed polyethylene waste may include film bags, milk cans or pouches, tote bags, drums, lids, agricultural films, and packaging materials. In some embodiments, based on the total weight of the waste polymer material feed, the waste polymer material feed contains up to 10% by weight of materials different from polymer materials.

[0069] Molten polymer material is supplied to the reactor and flows through a first reaction zone (i.e., comprising "P" reaction zones) as molten polymer material to be processed in the reactor. The molten polymer material processed in the reactor contacts the catalyst material through the flow in the first reaction zone, producing a molten product material containing depolymerization product material (and in some embodiments, also containing unreacted molten polymer material and / or intermediate reaction products). The molten product material is then collected.

[0070] In some embodiments, the catalyst is prepared by combining a ferrous-copper composite with an alumina support and reacting it with an inorganic acid to obtain a catalyst material. Other suitable catalyst materials include zeolites, mesoporous silica, alumina, H-mordenite zeolite, and various combinations thereof. The system can also operate in the absence of a catalyst and produce wax through thermal degradation.

[0071] The resulting molten product material is discharged from the reactor and collected / recovered from the reactor. In some embodiments, the collection of the molten product material is influenced by the molten product material stream discharged from the reactor. In those embodiments, in the case of multiple reactor modules, the molten product material is discharged from the first reactor module and supplied to the next reactor module in the series to influence further depolymerization within the next reactor module in the series, and this continues between each pair of adjacent reactor modules in the series.

[0072] In some implementations, the resulting depolymerization products include waxes, greases, oils, fuels, and C1-C4 gases, as well as grease-based stockpiles. Commercially available greases are typically made by mixing grease-based stockpiles with small amounts of specific additives to provide them with the desired physical properties. Generally, greases include four types: (a) mixtures of mineral oils and solid lubricants; (b) blends of residues (residues remaining after petroleum hydrocarbon distillation), unbound greases, rosin oil, and bitumen; (c) soap-thickened mineral oils; and (d) synthetic greases, such as polyalphaolefins and silicones.

[0073] In some embodiments, the polymer feed material is one or a combination of the following: virgin polyethylene (any one or a combination of HDPE, LDPE, LLDPE, and medium-density polyethylene (MDPE), virgin polypropylene, or post-consumer or post-industrial polyethylene or polypropylene (exemplary sources include bags, cans, bottles, drums, and / or other articles containing PE or PP), and it is desired to use one embodiment of the system disclosed herein to convert such polymer feed material into waxes with higher melt temperatures (melting temperatures of 106°C to 135°C), medium melt temperatures (melting temperatures of 86°C to 105°C), lower melt temperatures (melting temperatures of 65°C to 85°C), or even lower melt temperatures (melting temperatures of 40°C to 65°C).

[0074] In each case, the conversion is achieved by heating the polymer feed to produce a molten polymer material, which is then contacted with a catalyst material in a reaction zone set at a temperature of 325°C to 450°C. The quality of the resulting wax (a wax with a higher, medium, or lower melt temperature) depends on the residence time of the molten polymer material in the reaction zone. When operating in a continuous system, depending on the flow rate of the extruder or gear pump, the residence time varies from 1 to 120 minutes, preferably 5 to 60 minutes, in the case of 1-12 reactor modules connected in series. In some of these embodiments, the supply and heating of the polymer feed material are influenced by a combination of the extruder and the pump, wherein material discharged from the extruder is supplied to the pump. In some of these embodiments, the extruder 106 is a 10 HP, 1.5-inch (3.81 cm) Cincinnati Milacron Pedestal Extruder, Model Apex 1.5, and the pump 110 is 1.5 HP in size for a 1.5-inch (3.81 cm) pipe.

[0075] Pressure sensor PT01 monitors plugs inside the extruder (and before PT02, see below) to maintain system pressure below the maximum pressure (i.e., the maximum design pressure of reactor 100). Additionally, pressure sensor PT02 monitors plugs elsewhere in the system. Overpressure is controlled via pressure feedback from PT01 and PT02 to a controller that sends a command signal to shut down extruder 106 and pump 110, thereby preventing further pressure increases.

[0076] In some embodiments, reactor 100 is a first reactor 100, and the reaction zone of the first reactor is a first reaction zone, and the flow of molten polymer material through the first reaction zone is suspended (e.g., interrupted).

[0077] When “P” equals 1, the change involves connecting a total of “R” reactor modules out of “N-1” reactor modules not used in the components of the first reactor to the first reactor, where “R” is an integer from 1 to “N-1”, such that another reactor is added and said other reactor comprises a total of “R+1” reactor modules connected in series with each other, and such that said other reactor includes a second reaction zone comprising “R+1” module reaction zones. The other reactor is then configured to guide the flow of molten polymer material such that the flow of the molten polymer material processed by the reactor through the second reaction zone influences the generation of another depolymerization product material and its discharge from the other reactor.

[0078] When “P” is an integer greater than or equal to 2 but less than or equal to “N-1”, the change includes one of the following:

[0079] (a) Remove a total of “Q” reactor modules from “P” reactor modules in the first reactor, where “Q” is an integer from 1 to “P-1”, such that another reactor is added and said other reactor comprises a total of “PQ” reactor modules connected in series with each other, and said other reactor comprises a second reaction zone comprising “PQ” module reaction zones, wherein said other reactor is configured to guide the flow of molten polymer material such that the flow of the molten polymer material processed by the reactor through the second reaction zone affects the generation of another depolymerization product material and its discharge from the other reactor, or

[0080] (b) Connecting a total of “R” reactor modules out of “NP” reactor modules not used in the components of the first reactor to the first reactor, where “R” is an integer from 1 to “NP”, such that adding another reactor and said other reactor comprising a total of “P+R” reactor modules connected in series with each other, and including a second reaction zone comprising “P+R” module reaction zones, wherein said other reactor is configured to guide a flow of molten polymer material such that the flow of the molten polymer material processed by the reactor through the second reaction zone affects the generation of another depolymerization product material and its discharge from the other reactor.

[0081] When “P” equals “N”, the change involves removing a total of “Q” reactor modules from the first reactor out of “P” reactor modules, where “Q” is an integer from 1 to “P-1”, such that another reactor is added, and said other reactor comprises a total of “PQ” reactor modules connected in series with each other, and such that said other reactor includes a second reaction zone comprising “PQ” module reaction zones. The other reactor is configured to guide the flow of molten polymer material such that the flow of the molten polymer material processed by the reactor through the second reaction zone influences the generation of another depolymerization product material and its discharge from the other reactor.

[0082] In some implementations, after modifying the first reactor to influence the production of another reactor (by connecting / adding or removing any reactor module), a second reactor is used to produce the second depolymerization product material. In this regard, the polymer material is heated to produce a molten polymer material, and the molten polymer material is allowed to flow through a second reaction zone to influence the production of the second depolymerization product material. The second depolymerization product material is then collected from the reactor.

[0083] In some implementations, the same catalyst material is placed in each of the “N” reactor modules.

[0084] In some implementations, the reaction zones of each of the “N” reactor modules are the same or substantially the same.

[0085] Figure 3 A cross-sectional side view of a catalytic reactor 700 is shown, the reactor having a removable static mixer 710 configured to be heated via a hot fluid and / or molten salt. The static mixer 710 provides greater mixing within the catalytic reactor 700 and may result in a lower operating temperature. In other embodiments, the catalytic reactor 700 may include an annular insert. In other embodiments, the catalytic reactor 700 may have an empty interior. In some embodiments, the catalytic reactor 700 employs electric heating.

[0086] In addition to those already mentioned, the tubular construction of the catalytic reactor 700 offers several advantages. In particular, the use of a series-connected tubular reactor allows for reliable and consistent parameters, which in turn allows for consistent products. Specifically, compared to the final products produced using a continuous stirred reactor, the consistent flow through the tubular sections produces more predictable and narrower-range final products because the surface area and heat input of the catalyst are maximized. One advantage over continuous stirred reactors is the elimination of shortcuts; the flow in the tubular sections is assumed to move as a piston. Each assumed piston spends the same amount of time in the reactor. The tubular catalytic reactor can operate vertically, horizontally, or at any angle in between. The tubular catalytic reactor (reactor sections) and the corresponding preheating and cooling sections can be of a common size or one of several standard sizes. This not only allows for consistent material flow but also allows the tubular elements to be designed to be interchangeable between sections and easy to add, remove, clean, and repair. In at least some embodiments, the inner surface of the tubular sections is made of 304 or 316 steel.

[0087] Hot fluid and / or molten salt can enter jacket 720 via inlet / outlet 730. In some embodiments, catalytic reactor 700a is configured to house a thermocouple / pressure sensor (not shown) and includes an associated notch 735. The notch 735 is used to bring the thermocouple / pressure sensor into physical contact with the fluid. In some embodiments, the thermocouple / pressure sensor can be mounted in an orifice, which reduces the amount of material between the fluid and the sensor.

[0088] In some embodiments, the catalytic reactor 700 includes a removable screen 760 that can carry the catalyst. The removable screen 760 can be easily replaced, overcoming the disadvantages associated with packed bed reactors, including thermal gradients and challenging maintenance requirements, resulting in downtime. In some embodiments, the standardization of the removable screen 760 produces a consistent product leaving each section and / or allows standardization across multiple reactors.

[0089] In other or similar embodiments, the catalytic reactor 700a may include a removable adapter 740 having a cutout for a static mixer support. The static mixer support reduces forces on the static mixer 710, allowing for more powerful / rapid removal. The cutout of the adapter 740 improves the seal between the adapter and the screen. The catalytic reactor 700a may include flanges 750 at one or both ends for connecting the catalytic reactor 700a to other reactors, extruders, etc.

[0090] Figure 4 It is a set of parallel arrangements and Figure 3The diagram shows a cross-sectional front view of a similar catalytic reactor 700. The parallel arrangement allows for easier increases / decreases in overall productivity as needed with minimal alteration to the overall layout, and allows for multiple different levels of depolymerization to occur simultaneously.

[0091] The housing 800 allows the catalytic reactor 700 to be immersed in hot oil / molten salt, which is generally more efficient than electricity. The hot oil / molten salt is contained in the chamber 780. In some embodiments, the flange 770 allows multiple housings to be connected together.

[0092] Figure 5 It is shown in a horizontal structure. Figure 3 A cross-sectional side view of a parallel catalytic reactor arrangement. Compared to a single-tube arrangement, the parallel arrangement allows for the construction of higher flow rate units with smaller, potentially problematic, pressure drops. Horizontal configurations are generally easier to operate / maintain. Parallel catalytic reactor arrangements can also be oriented in a vertical configuration.

[0093] Figure 6 This is a cross-sectional side view of a vertical spiral internal catalytic reactor arrangement 500, the vertical spiral internal catalytic reactor device 500 having connections in series with... Figure 3 Two reactors 700 are shown similarly. A horizontal spiral mixer preheating section 820 is connected to one of the reactors 700. The spiral mixer can achieve better mixing by avoiding stagnation and hot spots.

[0094] The cooling section 830 of the spiral mixer is shown connected to another reactor 700 at a 45° inclination. The inclination allows the product to flow by gravity, while the 45° angle allows for full contact between the cooling medium and the product.

[0095] In the illustrated embodiment, the vertical spiral internal catalytic reactor arrangement 500 has several inlets / outlets to allow the use of hot fluid / molten salt mixtures; however, other heating techniques (e.g., but not limited to electric heating) may also be employed. In other embodiments, annular catalytic reactors and / or reactors with empty internal volumes may be used. In the same or other embodiments, electric heating may be used to heat reactor 700.

[0096] Figure 7 This is a perspective view of a horizontal reactor configuration 910 having an inner spiral reactor 700, the inner spiral reactor 700 being configured to employ a design similar to... Figure 3 A similar electric heater 870 is shown. In Figure 7 In this section, the reactor shell has been partially removed from the horizontal reactor configuration 910 to facilitate visualization of the location of the inner spiral reactor 700.

[0097] Example

[0098] Specific examples of synthetic wax-modified plastics

[0099] Table 1: Materials Used

[0100]

[0101] Example 1

[0102] In a first illustrative embodiment of the method of the present invention, the wax is produced by the depolymerization of post-consumer polyethylene. Various percentages of wax (by weight) are mixed with recycled plastic (HDPE clear milk cans). The resulting product exhibits an increased melt flow rate, leading to higher yields.

[0103] In the above embodiment, blending / extrusion was performed on a TEC 1.5” single-screw extruder. Melt flow index testing was conducted on an Arburg injection molding machine with a 3mm plaque mold. The barrel diameter was 9.5320 mm, the die length was 8.015 mm, and the orifice diameter was 2.09 mm. A six-minute preheating period was used. Melt flow index testing was performed at 190°C and a 2.16 kg load, according to ASTM D1238: Standard Test Method For Flow Rates of Thermoplastics.

[0104] The preparation and testing of the blends in Examples 1-3 are as follows.

[0105] (1) Blend the material with wax to produce the following mixture

[0106] • Control (100% control plastic)

[0107] • Mixture A (92% control plastic and 8% wax A)

[0108] • Mixture B (92% control plastic and 8% wax B)

[0109] • Mixture C (98% control plastic and 2% wax A)

[0110] (2) Extrude the mixture into granules (start with a mesh size of 40 / 100 / 40).

[0111] (3) Record pressure, temperature and production volume (time to weight).

[0112] (4) Record the current (Amps) every 10 minutes.

[0113] (5) Test the melt flow of the final extruded mixture.

[0114] Figure 8 Figure 900 shows the reduction in the amount of pressure required to push the wax-modified polymer material 920 through the extruder compared to the unmodified polymer material 910.

[0115] Table 2: Results of wax-modified polymers (Example 1)

[0116]

[0117] Example 2

[0118] In Example 2, polyethylene wax was mixed with HDPE polymer at different ratios (1%, 3%, 5%). It was found that increasing the amount of wax led to an increase in the melt flow index of the wax / polymer mixture.

[0119] In one embodiment, the initial melt flow index (MFI) of the initial HDPE is 0.40 g / 10 min (according to ASTM D1238). The HDPE is then converted into polyethylene wax and mixed into the same HDPE at a concentration of 1% by weight. The MFI of the HDPE / wax mixture increases to 0.42 g / 10 min.

[0120] In another embodiment, the initial HDPE is mixed with a polyethylene wax at a concentration of 5% by weight. The MFI of the HDPE / wax mixture is increased to 0.53 g / 10 min.

[0121] In the above embodiment, blending / extrusion was performed on a Merritt-Davis 2” extruder. Melt flow index testing was conducted on a Goettfert melt indexer. The barrel diameter was 9.5320 mm, the die length was 8.015 mm, and the orifice diameter was 2.09 mm. A six-minute preheating period was used. Melt flow index testing was conducted at 190°C and a 2.16 kg load, according to ASTM D1238: Standard Test Method For Flow Rates of Thermoplastics.

[0122] Table 3: Melt Flow Index Results (Example 3)

[0123]

[0124] Example 4

[0125] In Example 4, polyethylene wax (the applicant's A120) was mixed with post-consumer remilled high-density polyethylene natural bottle flakes (PCR HDPE) supplied by Envision at different ratios (2% and 4%). It was found that increasing the amount of wax resulted in an increase in the average elongation. Tests were conducted at a controlled screw speed (125 rpm) and a controlled pressure (~125 bar).

[0126] Table 4: Average values ​​of commercial extrusion evaluation test runs (Example 4)

[0127]

[0128] Table 4 shows the increase in melt flow when wax is added. Due to the increased flow rate of the mixture, running the process at a constant speed per minute reduces the pressure in the system and the amount of energy required compared to the control. Maintaining a constant pressure increases yield relative to the control.

[0129] Table 5: Injection Molding Data (Example 4)

[0130]

[0131] In one embodiment, the mixture from Table 4 is injected into a mold. The average elongation of the initial PCR HDPE is 374%.

[0132] In one group, PCR HDPE was mixed with polyethylene wax at a concentration of 2% by weight. The average elongation of the resulting PCR HDPE mixture was 444%.

[0133] In another group, PCR HDPE was mixed with polyethylene wax at a concentration of 4% by weight. The average elongation of the resulting PCR HDPE mixture was 607%.

[0134] The following conclusions can be drawn from the above test results:

[0135] The addition of waxes derived from the thermal or catalytic depolymerization of plastics has at least some of the following effects on polymer processing or reprocessing:

[0136] • Improve the melt flow index of the polymer

[0137] • Higher productivity

[0138] • Less back pressure and equipment wear

[0139] • Improved internal lubrication

[0140] • Powerful external lubrication

[0141] • When used in injection molding, the average increase in elongation

[0142] Although specific elements, embodiments, and applications of the invention have been shown and described, it should be understood that the invention is not limited thereto, as modifications can be made, in particular based on the foregoing teachings, without departing from the scope of this disclosure.

Claims

1. A method for forming a wax and using said wax to modify the processing and material properties of a polymer, said method comprising: (a) Select a solid polymer material; (b) Heating the solid polymer material in an extruder to produce a molten polymer material; (c) Filter the molten polymer material; (d) The molten polymer material is placed in a reactor through a chemical depolymerization process to produce a depolymerized wax material; (e) The depolymerized wax material is added to the prewax mixture to produce a modified polymer with an increased melt flow index.

2. The method according to claim 1, wherein the method is continuous or semi-continuous.

3. The method according to claim 1, wherein the polymer material is one or more selected from high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and polypropylene.

4. The method of claim 1, wherein the polymer material comprises recycled plastic.

5. The method of claim 1, wherein the polymer material and the prewax mixture contain recycled plastic.

6. The method according to claim 1, further comprising: (f) Filter the solid polymer material.

7. The method according to claim 1, further comprising: (f) Cool the depolymerized polymer material.

8. The method according to claim 7, further comprising: (g) Purify the depolymerized polymer material.

9. The method according to claim 8, wherein the purification step employs one of flash separation, absorption bed, clay polishing, and thin-film evaporator.

10. The method of claim 1, wherein the depolymerized material is added to the prewax mixture via a pipeline pump.

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