WO2025174356A1

WO2025174356A1 - Melt filtration for purification of post-consumer recyclate

Info

Publication number: WO2025174356A1
Application number: PCT/US2024/015482
Authority: WO
Inventors: William R. PODBORNY; Mick C. Hundley; Hrishikesh R. MUNJ; Bo Li
Original assignee: Equistar Chemicals LP
Current assignee: Equistar Chemicals LP
Priority date: 2024-02-13
Filing date: 2024-02-13
Publication date: 2025-08-21
Anticipated expiration: 2026-08-13

Abstract

A method for recycling plastic waste including the steps of (i) melting the polyolefin of the plastic waste at a processing temperature and a processing pressure, wherein the plastic waste is made from or containing (a) a polyolefin selected from the group consisting of polyethylene and polypropylene and (b) a contaminant having a melting point greater than the processing temperature at or below the processing pressure, thereby providing a polyolefin-based melt; (ii) mixing the polyolefin-based melt under a mixing force, thereby decreasing intermolecular interactions between the polyolefin and the contaminant; and (iii) passing the polyolefin-based melt through a filtering screen pack, thereby decreasing the amount of contamination in the polyolefin-based melt and purifying the polyolefin-based melt.

Description

MELT FILTRATION FOR PURIFICATION OF POST-CONSUMER RECYCLATE

FIELD OF THE INVENTION

[0001] In general, the present disclosure relates to the field of chemistry. More specifically, the present disclosure relates to post-consumer recyclate. In particular, the present disclosure relates to high-mesh, high-surface-area melt filtration of post-consumer recyclate, related processes, and products prepared therefrom.

BACKGROUND OF THE INVENTION

[0002] The downside to the demand for polyolefin plastics is an increase in plastic waste. As such, there is considerable interest in developing methods to recycle plastic waste. In addition to reducing the amount of plastic waste, other benefits of recycling plastic waste include reducing carbon footprint, consuming less energy, improving water consumption, and using less raw materials.

[0003] In many instances, before plastic waste is recycled and turned into usable resin, the plastic materials are gathered and sent through a process to produce plastic resin pellets. In some instances, the plastics recycling system is a mechanical recycling system, including the steps of sorting, cleaning, shredding, melting, and remolding.

[0004] In some instances, the resulting plastic resin pellets are made from or containing polyolefins, non-polyolefmic polymers, and other contaminants. In some instances, the non- polyolefinic polymers or the other contaminants are present in an amount that adversely affects the properties of the plastic resin pellets. In some instances, the non-polyolefmic polymers or the other contaminants provide stress points in articles made from or containing the plastic resin pellets.

BRIEF SUMMARY OF THE INVENTION

[0005] In a general embodiment, the present disclosure provides a method for recycling plastic waste including the steps of (i) melting the polyolefin of the plastic waste at a processing temperature and a processing pressure, wherein the plastic waste is selected from the group consisting of post-consumer recyclate and post-industrial recyclate, wherein the recyclate is made from or containing (a) a polyolefin selected from the group consisting of polyethylene and polypropylene and (b) a contaminant having a melting point greater than the processing temperature at or below the processing pressure, thereby providing a polyolefin-based melt; (ii) mixing the polyolefin-based melt under a mixing force, thereby decreasing intermolecular interactions between the polyolefin and the contaminant; and (iii) passing the polyolefin-based melt through a filtering screen pack, thereby decreasing the amount of contamination in the polyolefin-based melt and purifying the polyolefin-based melt.

[0006] In some embodiments, the present disclosure provides a post-consumer recycled resin prepared from a post-consumer recyclate, wherein the resin is selected from the group consisting of polyethylene and polypropylene. In some embodiments, the polyethylene is a high- density polyethylene.

[0007] In some embodiments, the present disclosure provides a post-industrial recycled resin prepared from a post-industrial recyclate, wherein the resin is selected from the group consisting of polyethylene and polypropylene. In some embodiments, the polyethylene is a high- density polyethylene.

[0008] In some embodiments, the present disclosure provides a polymer composition made from or containing resin selected from the group consisting of a post-consumer recycled resin and a post-industrial recycled resin.

[0009] In some embodiments, the present disclosure provides an article of manufacture made from or containing a resin selected from the group consisting of post-consumer recycled resins and post-industrial recycled resins.

[0010] While multiple embodiments are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description. As will be apparent, certain embodiments, as disclosed herein, are capable of modifications in various aspects, without departing from the spirit and scope of the claims as presented herein. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.

DETAILED DESCRIPTION OF THE INVENTION

[0011] While the provided embodiments will be described more fully hereinafter, these embodiments are provided to satisfy applicable law s and regulations. As such, it will be apparent to those skilled in the art that the embodiments can incorporate changes and modifications without departing from the general scope. This disclosure is intended to include the modifications and alterations in so far as the modifications and alterations come within the scope of the appended claims or the equivalents thereof.

[0012] As used in this specification and the claims, the singular forms “a,” “an,” and “the” include plural referents unless the context dictates otherwise.

[0013] As used in this specification and the claims, the terms “comprising,” “containing,” or “including” refer to the presence of that at least the named compound, element, material, particle, or method step in the composition, the article, or the method, but does not exclude the presence of other compounds, elements, materials, particles, or method steps even if the other such compounds, elements, materials, particles, or method steps have the same function as that which is named, unless expressly excluded in the claims. It is also to be understood that the mention of one or more method steps does not preclude the presence of additional method steps before or after the combined recited steps or intervening method steps between those steps expressly identified.

[0014] Moreover, it is also to be understood that the lettering of process steps or ingredients is for identifying discrete activities or ingredients and the recited lettering can be arranged in any sequence, unless expressly indicated.

[0015] For the purpose of the present description and of the claims which follow, except where otherwise indicated, numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified by the term “about”. Also, ranges include any combination of the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

[0016] Definitions

[0017] In the present description, the term “additive composition” refers to a composition made from or containing an additive.

[0018] In the present description, the term “a-olefin” or “alpha-olefin” refers to an olefin of formula CH2=CH — R, wherein R is a linear or branched alkyl containing from 1 to 10 carbon atoms. In some embodiments, the a-olefin is selected from the group consisting of propylene, 1- butene, 1 -pentene, 1 -hexene, 1 -octene. and 1 -decene.

[0019] In the present description, the term “contaminant” refers to any chemical substance present in a post-consumer recyclate (PCR), a post-industrial recyclate (PIR), a post-consumer recycled resin (PCR resin), or a post-industrial recycled resin (PIR resin), wherein the PCR, the PIR, the PCR resin, or the PIR resin is made from or containing a selected polymer and the presence of the chemical substance thereby renders the PCR, the PIR, the PCR resin, or the PIR resin compositionally different from the pure, selected polymer. In some embodiments, the contaminant is present in an amount ranging from parts per billion (ppb) to percentages, based upon the total weight of the PCR, the PIR, the PCR resin, or the PIR resin. In some embodiments, a multiplicity of contaminants is present. In some embodiments, the contaminant is selected from the group consisting of acry lonitrile butadiene styrene (ABS), calcium carbonate, coffee grounds, diapers, dirt, fillers, food stuffs, glass, grass, labels, metals (including aluminum), nylon, other inorganics, other polymers, paper, plant stems, polycarbonates, polyethylene terephthalate (PET), processing additives, property-imparting additives, rubbers, and wood.

[0020] In the present description, the term “dX value,” where X is 50 or 90, refers to the measured particle diameter upper limit for particles falling within the bottom 50% or 90% by mass, respectively, of the particle distribution. For example, a d50 value of 0.3 pm refers to 50% of the particles in the distribution by mass have a diameter of greater than 0.3 pm and 50% of the particles by mass have a diameter lower than 0.3 pm. The d50 value is also referred to as the median particle size herein.

[0021] In the present description, the term '‘plain Dutch weave” refers to a weave wherein the warp wires are larger than the weft wires. In the present description, the term “Dutch twill weave” refers to a weave wherein the wires cross two under and two over, allowing heavier wires and higher mesh counts.

[0022] In the present description, the term “elastomer” refers to polymer compounds having rubber-like properties and crystallinity in the range of from about 0 percent to about 20 percent.

[0023] In the present description, the term “first” refers to the order in which a particular species is presented and does not necessarily indicate that a “second” species will be presented. For example, “first polymer composition” refers to the first of at least one polymer composition. The term does not reflect priority, importance, or significance in any other way. Similar terms used that can be used herein include “second,” “third,” “fourth,” etc.

[0024] In the present description, the term '‘homopolymer" refers to polymers derived from a single monomeric unit. To the extent that a homopolymer is derived from more than a single monomeric unit, the incorporation of additional monomeric units has no measurable effect on the polymer’s primary, secondary' or tertiary' structure or no effect on the polymer’s physical or chemical properties. In other words, there is no measurable difference between a polymer, comprising 100 weight percent of a first monomeric unit, and a copolymer, including more than a single monomeric unit.

[0025] In the present description, the term “International Code Council (ICC) Certification” refers to products certified as using 100% post consumer resins.

[0026] In the present description, the term “interpolymer” refers to a polymer prepared by the polymerization of at least two ty pes of monomers or comonomers. The term “interpolymer” includes copolymers, terpolymers, tetrapolymers, and the like. In some embodiments, the term “copolymer” refers to polymers prepared from two different types of monomers or comonomers. In some embodiments, the term “terpolymer’⁷ refers to polymers prepared from three different types of monomers or comonomers. In some embodiments, the term “tetrapolymer” refers to polymers prepared from four different types of monomers or comonomers. In some embodiments, the term “copolymer” is used interchangeably with “interpolymer” and refers to polymers made from three or more different types of monomers or comonomers.

[0027] In the present description, the term “mesh” refers to a material or a network made from or containing interlaced strands of wires. In some instances, a mesh forms a barrier.

[0028] In the present description, the term “mesh size” refers to mesh number and the size of the openings in a linear inch of mesh screen, thereby determining the size of particles that can pass through these openings. In some instances, screens are made with different materials having different strand thicknesses. Notably, thicker strands provide smaller openings. As such, mesh size is not a precise measurement of the mesh opening size.

[0029] In the present description, the terms “mixing’' or “mixing force'’ refers to the manipulation of a heterogeneous physical stream for rendering the physical stream more homogeneous, that is, reducing non-uniformity and gradients in the physical stream.

[0030] In the present description, the terms “monomer” and “comonomer” are used interchangeably. The terms refer to any compound with a polymerizable moiety that is added to a reactor to produce a polymer. In those instances wherein a polymer is described as made from or containing one or more monomers, for example, a polymer made from or containing propylene and ethylene, the polymer, of course, is made from or containing units derived from the monomers, for example, — CH2 — CH2 — , and not the monomer itself, for example, CH2=CH2.

[0031] In the present description, the term “PCR” refers interchangeably to Post-Consumer Recycled or Post-Consumer Recyclate, including polymers such as high-density polyethylene (HDPE) and polypropylene (PP), which are recycled and reprocessed into a resin for use in various applications.

[0032] In the present description, the term “PIR” refers interchangeably to Post-Industrial Recycled or Post-Industrial Recyclate.

[0033] In the present description, the term “polymer” refers to a macromolecular compound prepared by polymerizing monomers of the same or different type. The term “polymer” includes homopolymers, copolymers, terpolymers, interpolymers, and so on.

[0034] In the present description, the term “polymer composition” refers to a composition made from or containing a polymer.

[0035] In the present description, the term “polyolefin” is used herein broadly and refers to polymers such as polyethylene, ethylene-alpha olefin copolymers (EAO), polypropylene, polybutene, and ethylene copolymers having at least about 50 percent by weight of ethylene polymerized with a lesser amount of a comonomer such as vinyl acetate, and other polymeric resins within the "olefin" family classification. [0036] In some instances, polyolefins are made by a variety of processes including batch and continuous processes using single, staged, or sequential reactors, slurry, solution, and fluidized bed processes and one or more catalysts including for example, heterogeneous and homogeneous systems and Ziegler, Phillips, metallocene, single-site, and constrained geometry catalysts to produce polymers having different combinations of properties.

[0037] In the present description, the term “post consumer recycled (PCR) resin" refers to the recycled product of waste created by consumers, including high-density polyethylene postconsumer recycled resin (HDPE PCR) and polypropylene post-consumer recycled resin (PP PCR). Among other forms, PCR resins may take the form of granules, pellets, and powders.

[0038] In the present description, the term “post industrial recycled (PIR) resin” refers to the recycled product of waste generated by manufacturers during the preparation of polymer-based products. In the present description, the disclosed, recycling processes for preparing and using PCR resins are extendable to PIR resins.

[0039] In the present description, the term “recycle” refers to the conversion of waste into a reusable material. The waste is created by consumers, in the case of post-consumer waste, or by manufacturers during the preparation of polymer-based products, in the case of post-industrial waste.

[0040] In the present description, the term “room temperature” refers to a temperature of about 25 degrees Celsius.

[0041] In the present description, the term “sandwich” refers to a screen pack, wherein individual screens are progressively stacked according to size and adjacent to each other. An example of a 3-screen. sandwich pack consists of a 40-mesh screen, a 100-mesh screen, and a 40- mesh screen. Similarly, an example of a 7-screen, sandwich pack consists a 40-mesh screen, a 100-mesh screen, a 200-mesh screen, a 325-mesh screen, a 200-mesh screen, a 100-mesh screen, and a 40-mesh screen.

[0042] In the present description, the term “screen mesh sum (SMS)” refers to the sum of the meshes of the individual screens constituting a filter pack. In some instances, SMS depends on system conditions, including melt throughput, melt properties, and pressure changes. In some embodiments and in view of a system’s screen mesh sum, a first filtering screen pack made from or containing a plurality of screens individually having a low mesh number achieves better filtration than a second filtering screen pack made from or containing an individual screen or a fewer number of individual screens having a higher mesh number. For example and in some instances, a plurality of screens, having individual mesh sizes of 50, filter particles having a particle size less than 300 microns.

[0043] In the present description, the term “shearing force’’ refers to the application of a cross-sectional, frictional force on the structural integrity of a polymer composition. In some instances, a shearing force is accompanied with shear heating.

[0044] In the present description, the term “square weave” or “plain weave” refers to a weave wherein each wire crosses over and under the other weave.

[0045] In the present description, the term “thermoplastic polymer” refers to a polymer that softens when exposed to heat and returns to its original condition when cooled to room temperature.

[0046] In the present description, the term “uniform block” refers to a screen pack, wherein individual screens of the same size are stacked according to size and adjacent to each other. An example of a uniform four-block screen pack consists of four 100-mesh screens. Similarly, an example of a multi -block, nine-block screen-pack construction consists of three 100-mesh screens, followed by three 200-mesh screens, and finally followed by three 325-mesh screens.

[0047] In the present description, the term “virgin polymers” refers to polymers prepared in polymerization processes from monomers, with or without catalysts or processing aids, and which are yet to be manufactured into first-use consumer or industrial products.

[0048] In the present description, the term “warp” refers to the lengthwise or longitudal wires held stationary in tension on a frame or loom.

[0049] In the present description, the term “weft” refers to crosswise wires (that is, horizontal wires) which are drawn over and under the w arp wares to make the mesh.

[0050] In a general embodiment, the present disclosure provides a method for recycling plastic waste including the steps of (i) melting the polyolefin of the plastic waste at a processing temperature and a processing pressure, wherein the plastic waste is selected from the group consisting of post-consumer recyclate and post-industrial recyclate, wherein the recy elate is made from or containing (a) a polyolefin selected from the group consisting of polyethylene and polypropylene and (b) a contaminant having a melting point greater than the processing temperature at or below⁷ the processing pressure, thereby providing a polyolefin-based melt; (ii) mixing the polyolefin-based melt under a mixing force, thereby decreasing intermolecular interactions between the polyolefin and the contaminant; and (iii) passing the polyolefin-based melt through a filtering screen pack, thereby decreasing the amount of contamination in the polyolefin-based melt and purifying the polyolefin-based melt. [0051] In some embodiments, the mixing force is combined with a shearing force, thereby increasing the disruption of the intermolecular interactions. In some embodiments, the mixing/shearing force is achieved using an apparatus selected from the group consisting of twin- screw extruders, packed beds, fluidized beds, extraction vessels with one or more trays, and solidliquid extraction systems. In some embodiments, the mixing/shearing force is achieved using a twin-screw extruder.

[0052] In some embodiments, the polyolefin-based melt is passed through a filtering screen pack. In some embodiments, the filtering screen pack is housed in a breaker plate.

[0053] In some embodiments, contamination reduction is proportional to the system’s screen mesh sum. In some embodiments, the filtering screen pack is made from or containing an individual screen, alternatively two screens, alternatively three or four screens, alternatively a plurality of screens.

[0054] In some embodiments, the filtering screen pack is made from or containing one or more individual screens having independently-selected mesh sizes. In some embodiments, the mesh size is in the range of 20 to 500 mesh, alternatively 20 to 400 mesh, alternatively 20 to 200 mesh.

[0055] In some embodiments, a screen is individually made from or containing a mesh pattern selected from the group consisting of a square weave pattern, a plain Dutch weave pattern, and a Dutch twill weave pattern.

[0056] In some embodiments, the mesh of a screen has a two-dimensional or a three- dimensional cell shape. In some embodiments, the two-dimensional shape is selected from the group consisting of triangle and quadrilateral. In some embodiments, the three-dimensional shape is selected from the group consisting of hexahedron, quadrilateral pyramid, tetrahedron, and triangular prism.

[0057] In some embodiments, the screens are made from or containing materials that are resistance to one or more of acid, alkali, and high temperatures. In some embodiments, the construction material, the pattern of the mesh, the cell shape, or a combination thereof provide an individual screen with strength to withstand high pressure and high temperature conditions.

[0058] In some embodiments, a continuous screen changer is passed through the polyolefin-based melt over time.

[0059] In some embodiments, an individual screen has a conical shape, wherein the screen’s surface are is increased over a flat screen. [0060] In some embodiments, an individual screen is a filtering sock. In some embodiments, the individual screen is a fdtering sock, have a Dutch twill weave.

[0061] In some embodiments, the system uses a screen-pack changer system, wherein screens are changed during the continuous operation of the system. In some embodiments, the changer system alternates between two screen packs, alternatively between three screen packs, alternatively between a plurality of screen packs.

[0062] In some embodiments, the systems use a sandwich screen pack or a uniform block screen pack.

[0063] In some embodiments, the method for recycling plastic waste includes the steps of:

(a) collecting the plastic waste from residential, commercial, and industrial sites, wherein the plastic waste is selected from the group consisting of postconsumer recyclate and post-industrial recyclate, and made from or containing a polyolefin and a contaminant;

(b) melting the polyolefin of the plastic waste at a processing temperature and a processing pressure, wherein the contaminant has a melting point greater than the processing temperature at or below the processing pressure, thereby providing a polyolefin-based melt;

(c) mixing the polyolefin-based melt under a mixing force, thereby decreasing intermolecular interactions between the polyolefin and the contaminant;

(d) passing the polyolefin-based melt through a filtering screen pack, thereby decreasing the amount of contamination in the polyolefin-based melt and purifying the polyolefin-based melt; and

(e) pelletizing the polyolefin-based melt, thereby forming a pelletized resin selected from the group consisting of a pelletized, post-consumer recycled (PCR) resin and a pelletized, post-industrial recycled (PIR) resin.

[0064] In some embodiments, the mixing force is combined with a shearing force, thereby increasing the disruption of the intermolecular interactions.

[0065] In some embodiments, the method for recycling plastic waste includes the steps of:

(a) collecting the plastic waste from residential, commercial, and industrial sites, wherein the plastic waste is selected from the group consisting of postconsumer recyclate and post-industrial recyclate, and made from or containing a polyolefin and a contaminant; (b) melting the polyolefin of the plastic waste at a processing temperature and a processing pressure, wherein the contaminant has a melting point greater than the processing temperature at or below the processing pressure, thereby providing a polyolefin-based melt;

(c) mixing and shearing the polyolefin-based melt under a combination of mixing and shearing forces, thereby decreasing intermolecular interactions between the polyolefin and the contaminant;

[0066] In some embodiments, the method for recycling plastic waste further includes the steps of:

(a.i) sorting the plastic waste; and

(a.ii) cleaning the plastic waste.

[0067] In some embodiments, the method for recycling plastic waste further includes the steps of:

(a.iii) sieving the plastic waste;

(a.iv) separating the plastic waste by particle size; and

(a.v) collecting the plastic waste in the form of granules or powders.

[0068] In some embodiments, the method for recycling plastic waste includes the steps of:

(a.i) sorting the plastic waste;

(a.ii) cleaning the plastic waste;

(a.iii) sieving the plastic waste; (a.iv) separating the plastic waste by particle size;

[0069] In some embodiments, the method for recycling plastic waste include one or more cleaning steps. As previously noted, the mention of one or more method steps does not preclude the presence of additional method steps before or after the combined recited steps or intervening method steps between those steps expressly identified.

[0070] In some embodiments, the plastic waste is made from or containing automobile parts, bleach bottles, food containers, freezer and shopping bags, milk jugs, outdoor furniture, packaging materials, piping, plastic bottles, playground equipment, shampoo bottles, signage and fixtures, toys, and contaminants. In some embodiments, the contaminants are selected from the group consisting of acrylonitrile butadiene styrene (ABS), calcium carbonate, coffee grounds, diapers, dirt, fillers, food stuffs, glass, grass, labels, metals (including aluminum), nylon, other inorganics, other polymers, paper, plant stems, polycarbonates, polyethylene terephthalate (PET), processing additives, property-imparting additives, robbers, and wood.

[0071] In some embodiments, the present disclosure provides a post-consumer recycled resin prepared from a post-consumer recyclate, wherein the resin is selected from the group consisting of polyethylene and polypropylene. In some embodiments, the polyethylene is a high- density polyethylene.

[0072] In some embodiments, the present disclosure provides a post-industrial recycled resin prepared from a post-industrial recyclate, wherein the resin is selected from the group consisting of polyethylene and polypropylene. [0073| In some embodiments, the present disclosure provides a polymer composition made from or containing resin selected from the group consisting of a post-consumer recycled resin and a post-industrial recycled resin. In some embodiments, the polymer composition is made from or containing:

(a) from 5 % by weight to 95 % by weight, based upon the total weight of the polymer composition, of a resin selected from the group consisting of a post-consumer recycled resin and a post-industrial recycled resin; and

(b) from 5 % by weight to 95 % by weight, based upon the total weight of the polymer composition, of a virgin polymer.

[0074] In some embodiments, the resin is selected from the group consisting of HDPE PCR and PP PCR. In some embodiments, the resin is the base resin of the polymer composition. In some embodiments, the resin is a complementary resin. In some embodiments, the resin is a component in an additive composition or a filler, for use with a virgin or other PCR resin. In some embodiments, the resin is used as a filler in amount alternatively up to 95 % by weight, alternatively up to 90 % by weight, alternatively up to 80 % by weight, alternatively up to 70 % by weight, alternatively up to 60 % by weight, alternatively up to 50 % by weight, alternatively from 0.5 % by weight to 30 % by weight, alternatively from 1.0 % by weight to 20% by weight, based upon the total weight of the polymer composition.

[0075] In some embodiments, the resin bears the International Code Council (ICC) Certification.

[0076] In some embodiments, the polymer composition is further made from or containing an additive composition. In some embodiments, the additive composition imparts properties such as thermal stability, light and ultraviolet protection, and color. In some embodiments, the additive composition is present in an amount from 0.05 % by weight to 10 % by weight, alternatively from 0.1 % by weight to 8 % by weight, based upon the total weight of the polymer composition.

[0077] In some embodiments, the present disclosure provides an article of manufacture made from or containing a resin selected from the group consisting of post-consumer recycled resins and post-industrial recycled resins. In some embodiments, the article of manufacture is selected from the group consisting of blow-molded articles, films, flexibles, injection-molded articles, packaging, and piping. In some embodiments, the article of manufacture is useful in noncosmetic-intensive, post consumer recycled resin applications, including agricultural film and trash bags.

Claims

CLAIMS What is claimed is:

1. A method for recycling plastic waste comprising the steps of:

(i) melting the polyolefin of the plastic waste at a processing temperature and a processing pressure, wherein the plastic waste is selected from the group consisting of postconsumer recyclate and post-industrial recyclate, wherein the recyclate is made from or containing (a) a polyolefin selected from the group consisting of polyethylene and polypropylene and (b) a contaminant having a melting point greater than the processing temperature at or below the processing pressure, thereby providing a polyolefin-based melt;

(ii) mixing the polyolefin-based melt under a mixing force, thereby decreasing intermolecular interactions between the polyolefin and the contaminant; and

(iii) passing the polyolefin-based melt through a filtering screen pack, thereby decreasing the amount of contamination in the polyolefin-based melt and purifying the polyolefin-based melt.

2. The method for recycling plastic waste of Claim 1, comprising the steps of:

(a) collecting the plastic waste from residential, commercial, and industrial sites, wherein the plastic waste is selected from the group consisting of post-consumer recyclate and post-industrial recyclate, and comprising the polyolefin and the contaminant;

(d) passing the polyolefin-based melt through a filtering screen pack, thereby decreasing the amount of contamination in the polyolefin-based melt and purify ing the polyolefin-based melt; and

3. The method for recycling plastic waste of Claim 1, comprising the steps of: (a) collecting the plastic waste from residential, commercial, and industrial sites, wherein the plastic waste is selected from the group consisting of post-consumer recyclate and post-industrial recyclate, and made from or containing a polyolefin and a contaminant;

(b) melting the polyolefin of the plastic waste at a processing temperature and a processing pressure, wherein the contaminant has a melting point greater than the processing temperature at or below the processing pressure, thereby providing a polyolefin- based melt;

4. The method for recycling plastic waste of Claim 1. wherein the plastic waste comprises automobile parts, bleach bottles, food containers, freezer and shopping bags, milk jugs, outdoor furniture, packaging materials, piping, plastic bottles, playground equipment, shampoo bottles, signage and fixtures, toys, and contaminants.

5. The method for recycling plastic waste of Claim 4, wherein the contaminants are selected from the group consisting of acrylonitrile butadiene styrene (ABS), calcium carbonate, coffee grounds, diapers, dirt, fillers, food stuffs, glass, grass, labels, metals (including aluminum), nylon, other inorganics, other polymers, paper, plant stems, polycarbonates, polyethylene terephthalate (PET), processing additives, property-imparting additives, rubbers, and wood.

6. A post-consumer recycled resin comprising (a) 50 to 100 weight by percent of a resin selected from the group consisting of polyethylene and polypropylene and (b) 0 to less than 50 weight by percent of contaminants, having a melting point greater than the melting point of the resin, based upon the total weight of the post-consumer recycled resin.

7. An article of manufacture comprising the post-consumer recycled resin of Claim 6.