Upcycling processes for unsorted waste streams

Abstract

This is a dynamic process for upcycling polymers. Polymers from various post-consumer waste streams are collected in a mixture. The mixture is extruded and combined with a liquid additive containing a specific PE wax that is on the verge of polymerization. The liquid additive is repolymerized into low-density polyethylene (LDPE) to form pellets. The pellets are transported to a reactor and immersed in a suitable solvent to dissolve the LDPE, resulting in the gradual and orderly separation of the remaining polymers from each other and the production of a layered matrix. A suitable solvent, enzyme, or chemical suitable for depolymerization is transported to the reactor through a separate pipe attached to a tank containing the appropriate depolymerization agent. The process is repeated by adding the appropriate solvent, enzyme, or depolymerization agent to each polymer in the mixture, depolymerizing the layered matrix layer by layer, thereby dissolving the remaining polymers in an orderly manner and producing a laminated wax-like material for upcycling.

Description

Technical Field

[0001] The present invention relates to an upcycling process, and more specifically, to an upcycling process for plastics applicable to used plastic products without the need to separate used plastic products by plastic type.

Background Art

[0002] Description of Related Art Various designs related to the upcycling process have been designed in the past. However, none of them include a process that enables dynamic upcycling of plastics through melting and depolymerization without separating plastics by type.

[0003] According to the applicant, the related reference is considered to correspond to US Patent Publication No. 2003 / 0146547 regarding a method for recovering mixed plastic substances. According to the applicant, another related reference is considered to point to US Patent No. 5,198,471 regarding the reuse of polymers by selective dissolution. However, none of these references teach a process for the upcycling of plastics through dynamic depolymerization that eliminates the need to separate various plastics by type.

[0004] Among other references describing the closest subject matter, a number of rather complex features are introduced that cannot solve the problem in an efficient and economical manner. None of these patents suggest the novel features of the present invention.

Summary of the Invention

[0005] One object of the present invention is to provide a process that can be used to dynamically upcycle plastics from used plastic products.

[0006] Another object of the present invention is to provide a process that can be applied to unsorted used plastic products.

[0007] Yet another object of the present invention is to provide a process that helps reduce plastic waste and pollution.

[0008] Still another object of the present invention is to provide a process for upcycling plastics through depolymerization.

[0009] Another object of the present invention is to provide a device that is inexpensive to implement and maintain while retaining its effectiveness.

[0010] A further object of the present invention is disclosed in the following part of this specification, where a detailed description is made for the purpose of fully disclosing the present invention without limitation.

Brief Description of the Drawings

[0011] Considering the above objects and other related objects, the present invention is composed of details of the construction and combination of parts so that it can be more fully understood from the following description when read in conjunction with the accompanying drawings.

Figure 1

Modes for Carrying Out the Invention

[0012] Referring now to the drawings, when the present invention is generally referred to by the numeral (10), it can be observed that it basically includes upcycled plastics (10) achieved through the process (20).

[0013] The upcycling of polymers enables the polymers to be reused and recycled in a way that helps reduce additional waste, as achieved in process (20). Process (20) includes a first step (22) that involves collecting and mixing various plastics or polymers from diverse used waste streams to create a mixture. The plastics contained in the waste streams include, but are not limited to, low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC). It may be appropriate to shred the mixture from the first step (22).

[0014] Process (20) includes a second step (24) that involves processing and extruding a mixture of various types of plastics from the first step (22) by an extrusion screw. The second step (24) will combine the mixture with a liquid additive that contains a specific polyethylene wax in canola oil as a chemical carrier. It will be understood that the polyethylene wax is on the verge of polymerization. Therefore, the polyethylene wax is meant to be produced by dissolving LDPE in a heptane bath in a specific way. The heptane bath is to be maintained at a temperature of 155°C to 255°C by immersing the LDPE in the heptane bath for a time between 15 and 45 minutes.

[0015] When polyethylene wax is added to a mixture as a liquid additive and then repolymerized by extrusion heat, the polyethylene wax can have a high molecular weight that causes the polyethylene wax to become LDPE once again. Process (20) includes a third step (26) that involves repolymerizing the polyethylene wax from the second step (24) into LDPE, or repolymerized LDPF. During the third step (26), pellets from the mixture can be formed at the end of the extrusion process. Importantly, the pellets can contain a heterogeneous mixture of various plastics in addition to the repolymerized LDPE from the third step (26).

[0016] The process (20) further includes a fourth step (28) involving introducing pellets from the third step (26) into a reactor. Depolymerization will occur within the reactor. Further, the fourth step (28) includes immersing the pellets in the reactor in heptane or another solvent suitable for polyethylene wax repolymerized to LDPE. The heptane will be maintained at a temperature of 155°C to 255°C. The pellets will be immersed in the heptane for 1 hour. It will be understood that the heptane is conveyed to the reactor via a pipe from a tank containing a large amount of heptane or a suitable solvent for LDPE and HDPE, or otherwise the first arm. Immersing the pellets in heptane will dissolve all of the LDPE and HDPE. Importantly, the solvation from the second step (24) of LDPE, which can be facilitated by agitation, causes all of the polymers or plastics not dissolved by the heptane, such as PET, PP, PVC, and PS, to gradually separate from each other because they are all bound by the same component, namely the repolymerized polyethylene wax. Separation occurs because LDPE previously functioned as a molecular entanglement factor among the polymers of the heterogeneous mixture. The remaining polymers are separated based on their specific density and buoyancy in the solvent tank, and the specific density of the solvent tank is dynamically calculated and changed by using different suitable solvents of different specific densities, the goal of which is to sink specific plastics and float others in order to further push the polymer layer arrangement for each type. This can result in a layered substrate having a defined composition that enables subsequent solvation processes to be carried out within the same reactor and chemically fractionate the mixture.

[0017] The layered substrate will be, for example, PP at the top, PS in the lower layer of PP, PVC in the lower layer of PS, and PET at the bottom of the lower layer of PVC in that order. The density of PP is speculated to be 0.895 g / cm 3 ~0.923 g / cm 3 The density of PS is 1.051 g / cm3 is presumed to be. The density of PVC is 1.379 g / cm 3 is presumed to be. The density of PET is 1.382 g / cm 3 is presumed to be.

[0018] Process (20) may include a fifth step (32) involving opening the connection of the reactor to the first arm and recovering the heptane remaining in the reactor using the first arm via distillation. This enables the reactor and the layered substrate to be depolymerized again later for the remaining layer of the polymer. This means that the process enables the remaining polymer to be dissolved in an orderly manner.

[0019] Process (20) will continue to be applied to the layered substrate. It will be understood that the fourth step (28) and the fifth step (32) are repeated using various solvents to be compatible with each of the next polymers to be dissolved. Process (20) includes a sixth step (34) involving repeating the fourth step (28) and the fifth step (32). The layered substrate may have the top layer of PP to be treated. The first arm is closed, then the second arm attached to the reactor is opened, and the second arm may be connected to a second tank containing a second solvent compatible with PP such as phthalic anhydride. The layered substrate is immersed in the second solvent at a temperature of 155°C to 255°C for 1 hour until the PP is dissolved, and then changed into a waxy substance via cooling and precipitation. Immediately afterwards, the reactor is opened and a volatilization temperature is applied to the reactor to phase-separate the second solvent via distillation, and the second solvent can be extracted by recovering the second solvent by the second arm. Thus, the layered substrate comes to be acted upon by the third arm and the third solvent to dissolve an additional layer of the polymer.

[0020] The process (20), and more specifically, the sixth step (34), will be understood to be repeatable until each layer of the polymer in the layered substrate has been processed. By treating each layer with a different solvent, the polymer of the next layer is dissolved. Each solvent will be carried using a different arm attached to a different tank containing the required solvent(s).

[0021] At the end of the process (20), a laminated wax-like substance will result. The laminated wax-like substance can be used as a raw material for manufacturing new plastic products or as a raw material for other industries such as the lubricating oil industry. Alternatively, in the worst-case scenario, the laminated wax-like substance can be deposited at a waste treatment site. Since the laminated wax-like substance has a more compressed volume, a better dispersed particle size, and a smaller molecular weight, and thus results in a more environmentally friendly chemical structure, it can lead to better results than using untreated plastics.

[0022] It will be understood that the polymer from any other used product can be combined and treated with other suitable solvent(s), heat-resistant enzymes, or any chemical substance compatible with depolymerization, not limited to the polymers or solvents described above. The process (20) can be repeated as many times as necessary depending on the number of layers in the layered substrate.

[0023] The foregoing description best conveys an understanding of the objects and advantages of the present invention. Different embodiments can be configured with the inventive concept of the present invention. It will be understood that all events disclosed herein are to be construed as merely illustrative and not in a limiting sense.

Industrial Applicability

[0024] The process for upcycling polymers has several implementations in terms of industrial applicability. The process helps to achieve the dynamic upcycling of plastics from used plastic products. The process is easily applicable to unsorted used plastic products and helps to reduce plastic waste and pollution. Importantly, upcycling is achieved through depolymerization. The process begins by collecting polymers in a mixture from various used waste streams. Next, the mixture is extruded and combined with a liquid additive, which importantly contains a specific PE wax that is just before polymerization. Next, the liquid additive is repolymerized into low-density polyethylene (LDPE) to form pellets. Next, the pellets are received in a reactor. Inside the reactor, the pellets are immersed in a suitable solvent, enzyme, or chemical compatible with depolymerization that is contained within the reactor to dissolve the LDPE. This causes the remaining polymers to be separated stepwise and orderly from each other and to form a layered substrate. The suitable solvent, enzyme, or chemical compatible with depolymerization is carried to the reactor via an independent pipe attached to a tank containing the appropriate depolymerizing agent. The process repeats the depolymerization of the layered substrate layer by layer by adding a suitable solvent, enzyme, or depolymerizing agent for each of the polymers in the mixture, resulting in the remaining polymers being dissolved in an orderly manner and producing a laminated wax-like substance for upcycling.

Claims

1. 1. A process for upcycling a polymer, comprising: a) providing a mixture from various post-consumer waste streams; b) extruding the mixture through an extrusion screw using a wax dispersed in a liquid carrier; c) repolymerizing the wax in the liquid carrier to a low density polyethylene, forming pellets of the combination of the mixture and the repolymerized wax at the end of the extrusion process; d) immersing the pellets in a reactor in a suitable solvent to dissolve the repolymerized wax and separate the remainder of the polymer to yield a layered matrix; e) opening the reactor and recovering the remainder of the suitable solvent in the reactor via distillation; and f) adding a suitable solvent for the remainder of the polymer to depolymerize the layered matrix layer by layer to produce a laminated wax-like material.

2. 10. The process of claim 1, wherein the wax has a molecular weight at least 50% of the molecular weight of low density polyethylene.

3. 2. The process of claim 1, wherein the polymer is at least one of low density polyethylene (LDPE), high density polyethylene (HDPE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), or polyvinyl chloride (PVC).

4. The process of claim 1 , wherein the mixture is shredded.

5. 10. The process of claim 1, wherein the liquid carrier comprises polyethylene wax in a bio-based oil as a carrier.

6. 6. The process of claim 5, wherein the polyethylene wax is prepared by dissolving a polymer in a first solvent.

7. 7. The process of claim 6, wherein the polymer is LDPE and the initial solvent is heptane.

8. 7. The process of claim 6, wherein the polymer is immersed in the first solvent for a time between 15 and 45 minutes, and the first solvent is maintained at a temperature between 155°C and 255°C.

9. 10. The process of claim 1, wherein the pellets are kept submerged in the suitable solvent for one hour per cycle, one of the polymers is treated per cycle, and the suitable solvent is maintained at a temperature of 155°C to 255°C.

10. 10. The process of claim 1, wherein the suitable solvent combination is selected based on solvent density and the role of the solvent density in density separation of the dissolved polymer.

11. 10. The process of claim 1, wherein said polymer being treated should sink in said suitable solvent and the remainder of said polymer not being treated should float in said suitable solvent.

12. The process of claim 1 , wherein the remainder of the polymer is separated by density.

13. 10. The process of claim 1, wherein organics, metals, and glasses are found in the waste stream and further separated by density.

14. 10. The process of claim 1, wherein the laminated wax-like material serves as a raw material for manufacturing new products.

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