Selectively-reduced GELS and stress points of microfine PCR / PIR resin

Abstract

A method for recycling plastic waste including the step of chemically-modifying the plastic waste, thereby reducing selectively the proportion of contaminants immiscible with a microfine PCR / PIR resin, wherein the plastic waste is selected from the group consisting of post-consumer recyclate and post-industrial recyclate.

Description

SELECTIVELY-REDUCED GELS AND STRESS POINTS OF MICROFINE PCR / PIR RESINFIELD 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 chemical modification of post-consumer recyclate, thereby reducing selectively the proportion of contaminants immiscible with a microfine PCR / PIR resin, 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-polyolefinic polymers, and other contaminants. In some instances, the non- polyolefimc 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-polyolefinic polymers or the other contaminants provide gels or stress points in articles made from or containing the plastic resin pellets.

[0005] In some instances, the contaminants vary in particle size. In some instances, there is a particle-size differential between the contaminant particles and the polyolefin particles, resulting in stress points in articles made from the polyolefin. In some instances, the particle-size differential couples with inadequate adhesion between the contaminants and the polymer, thereby contributing a source of stress points.

[0006] In some instances, the contaminants include cellulose-based components, which are hydrophilic and polar. As such and in some instances, the cellulose-based contaminants are incompatible with hydrophobic, non-polar resins such as polyethylene or polypropylene. In someinstances, cellulose-based components do not disperse uniformly within a hydrophobic, non-polar resin matrix; instead, the cellulose-based components aggregate, thereby providing gels or stress points in articles prepared from the resin matrix.

[0007] In some instances, the contaminants include polymers such as polyethylene terephthalate or nylon. These polymeric contaminants are incompatible with polyethylene and polypropylene and yield gels or stress points in film or thin containers made therefrom. In some instances, these polymeric contaminants decompose or depolymerize in post-recycling processes, thereby contributing volatile organic compounds and odors.BRIEF SUMMARY OF THE INVENTION

[0008] In a general embodiment, the present disclosure provides a method for recycling plastic waste including the step of chemically-modifying the plastic waste, thereby reducing selectively the proportion of contaminants immiscible with a microfine PCR / PIR resin, wherein the plastic waste is selected from the group consisting of post-consumer recyclate and postindustrial recyclate.

[0009] 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.

[0010] 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.

[0011] 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.

[0012] 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.

[0013] 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, withoutdeparting 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

[0014] While the provided embodiments will be described more fully hereinafter, these embodiments are provided to satisfy applicable laws 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.

[0015] As used in this specification and the claims, the singular forms “a,” "an." and “the” include plural referents unless the context dictates otherwise.

[0016] As used in this specification and the claims, the terms “comprising,” “containing,” or “including” mean that at least the named compound, element, material, particle, or method step is present 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.

[0017] 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.

[0018] 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.

[0019] Definitions

[0020] In the present description, the term “additive composition” refers to a composition made from or containing an additive.

[0021] In the present description, the term “a-olefin” or “alpha-olefin” means an olefin of formula CH2=CH — R, wherein R is a linear or branched alky l containing from 1 to 10 carbonatoms. In some embodiments, the a-olefm is selected from the group consisting of propylene, 1- butene, 1 -pentene, 1 -hexene, 1 -octene, and 1 -decene.

[0022] In the present description, the term ‘'block copolymer structure” refers to a structure wherein two or more polymer chains A, B, C, . . . . with different properties are bonded in a linear manner (for example, A-B, A-B-A, and A-B-C). Examples include an A-B block copolymer structure, wherein polymer chain A and polymer chain B are bonded in a linear manner.

[0023] 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.

[0024] In some embodiments, a multiplicity of contaminants is present. In some embodiments, the contaminant is selected from the group consisting of acrylonitrile butadiene sty rene (ABS), calcium carbonate, coffee grounds, diapers, dirt, fillers, food stuffs, glass, grass, labels, metals (including aluminum), nylon, other inorganics, paper, plant stems, polycarbonates, polyethylene terephthalate (PET), other polymers, processing additives, property -imparting additives, rubbers, and wood.

[0025] In the present description, the term '‘depolymerization or primary recycling” refers to the conversion of polymeric waste into products having a quality' equivalent to that of the “virgin polymer” and encompasses methods to break down polymer chains into constituent monomers, which are then available for repolymerization.

[0026] For example, nylon 6 (or poly caprolactam) is prepared from the monomer caprolactam while nylon 66 (or poly(hexamethylene adipamide)) is prepared from the monomers hexamethylene diamine and adipic acid. The depolymerization of nylon 6 and nylon 66 would yield the monomers (a) caprolactam and (b) hexamethylene diamine and adipic acid, respectively. Processes for depolymerization of nylon 6 and nylon 66 include acid-catalyzed, ammonolysis, base-catalyzed, pyrolysis, and water.

[0027] Similarly, polyethylene terephthalate is treated with a chemical reaction and heat to yield the constituent monomers. Processes for depolymerization of polyethylene terephthalate include alcohol-alkali combined, ammonolysis, glycolysis, hydrolysis, and methanolysis.

[0028] Ammonolysis depolymerization yields bis(2-hydroxyethylene) terephthalamide. Glycolysis depolymerization uses monoethylene glycol to induce a transesterification reaction in polyethylene terephthalate, thereby yielding bis(2 -hydroxyethyl) terephthalate as intermediate. Subsequently, the bis(2 -hydroxy ethyl) terephthalate reacts with water to yield finally terephthalic acid and monoethylene glycol monomers.

[0029] Hydrolysis depolymerization yields terephthalic acid and monoethylene glycol monomers. Methanolysis depolymerization yields dimethyl terephthalate and monoethylene glycol monomers.

[0030] In neutral hydrolysis, water or steam is used, without adding an acid-base catalyst, at atemperature of 250-300 degrees Celsius and a pressure of 1.5-4.0 MPa. In neutral hydrolysis, catalyst systems, such as metal salts, are introduced, thereby improving the reaction speed. In some instances, the catalyst system is made from or containing a zeolite.

[0031] In the present description, the term "cellulose-dispersant ’ or “hydrophobic-treating compound” refers to a chemical compound having a first resin affinity segment, a second cellulose affinity segment, and a block copolymer structure or a gradient copolymer structure. The resin affinity segment represents the hydrophobic portion. As used herein, the term “cellulose- dispersing segment” refers to the resin affinity segment. The cellulose affinity segment represents the hydrophilic portion. As used herein, the term “cellulose immobilizing segment” refers to the cellulose affinity segment.

[0032] Cellulose has hydroxyl groups on its surface, which is coated with the cellulose affinity segment of the dispersant. The resin affinity’ segment of the dispersant hydrophobizes the cellulose surface, has a structure or hydrophobicity’ similar to the target resin, and improves the strength at the interface between cellulose and a resin. Cellulose, which is hydrophobized on its surface, is uniformly dispersed even in a thermoplastic resin with hydrophobicity’, such as polyethylene (PE) or polypropylene (PP).

[0033] In some embodiments, the resin affinity’ segment is made from or containing a monomer unit selected from the group consisting of (meth)acrylate-based monomers, (meth)acrylamide-based monomers, and styrene-based monomers. In some embodiments, the cellulose affinity segment is made from or containing a monomer unit selected from the group consisting of (meth)acrylate-based monomers, (meth)acrylamide-based monomers, and styrene- based monomers. In some embodiments, the dispersant has a block copolymer structure or a gradient copolymer structure. In some embodiments, the dispersant is an A-B diblock copolymer. In some embodiments, the dispersant is designed and synthesized by living radical polymerization (LRP).

[0034] 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.

[0035] 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.

[0036] In the present description, the term “gradient copolymer structure” refers to a structure with a repeating-unit distribution gradient, such that the proportion of unit A decreases while the proportion of unit B increases from one end of a polymer chain with abundant unit A to the other end with abundant unit B.

[0037] 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.

[0038] In the present description, the term “International Code Council (ICC) Certification” refers to products certified as using 100% post consumer resins.

[0039] In the present description, the term “interpolymer” means a polymer prepared by the polymerization of at least two types 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” 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.

[0040] In the present description, the term "ionomer polymer" refers to an ionic copolymer of at least 50 mol percent of an ethylenically unsaturated alpha-olefin of 2 to 10 carbon atoms, from about 0.2 to about 50 mol percent of an alpha, beta-ethenically unsaturated carboxylic acidhaving from 3 to 8 carbon atoms, and optionally, other ethylenically unsaturated comonomers, wherein the copolymers having from 10% to 100% of the carboxylic acid groups in salt form with metal ions.

[0041] In the present description, the term “microfine resin particle” refers to a polyolefin resin microparticle that is spherical or substantially spherical and has an average particle size from 1 to 2000 pm, alternatively 1-1000 pm, alternatively 1-100 pm, alternatively 1-50 pm, alternatively 1-20 pm, alternatively 10-20 pm, with a narrow size distribution.

[0042] In some instances, a dispersion is used to prepare the microfme resin particles. The dispersion is derived by subjecting a polymeric thermoplastic resin to vigorous agitation in the presence of water and a resin-dispersing agent at a temperature above the melting point of the resin and at a pressure for maintaining the water in a liquid state. In some embodiments, the resin dispersing agent is selected from the group consisting of water soluble block copolymers, water insoluble ionomer polymers, soaps, and detergents. In some embodiments, the water soluble block copolymer is a block copolymer of ethylene oxide and propylene oxide.

[0043] Next, the microfine particles are derived from cooling the dispersion to below the melting point of the resin. Finally, the microfme particles are separated from the aqueous phase in the form of discrete particles.

[0044] The temperature of operation is dependent upon the melting point, melt flow properties, decomposition temperature, and intended fineness of dispersion of the selected synthetic organic thermoplastic resin. It is believed that the resin is dispersable at temperatures commencing with the resin’s melting points. It is further believed that, in some instances, increases in dispersion temperature beyond the melting point and up to the decomposition of the resin correspond to increases in the fluidity of the molten resin. Furthermore and in some instances, as the fluidity of the melt increases, the dispersion develops lower average particle sizes without increases in agitation.

[0045] 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, — CFh — CH2 — , and not the monomer itself, for example, CH?=CH2.

[0046] In the present description, the term “PCR” refers interchangeably to Post-ConsumerRecycled 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.

[0047] In the present description, the term “PCR / PIR resin” refers to PCR resin, PIR resin, or both.

[0048] In the present description, the term “PIR” refers interchangeably to Post-Industrial Recycled or Post-Industrial Recy elate.

[0049] In the present description, the term “polyamide” refers to a polymer bearing recurring amide groups in the polymer's backbone. Poly caprolactam and poly(hexamethylene adipamide) are commercially-available polyamides, which are respectively designated as “nylon 6” and “nylon 66”. Other nylons include nylon 11, nylon 12, nylon 46, and nylon 612.

[0050] As polyamide fibers and polyamide thermoplastics, aliphatic polyamides are used in various applications. In some instances, polyamide fibers are prepared in a melt-spun process and used in apparel, carpets, home textiles, surgical sutures, tire reinforcement, and other applications.

[0051] In some instances, polyamide thermoplastics are prepared with processes blow molding, extrusion, injection molding, and other thermoplastic processing methods. Polyamide thermoplastics are used in automotive applications (including body panels, fenders, and head light housings), electrical applications (including connectors, plugs, sockets, and switches), packaging applications (including food containers as moisture and oxygen barriers), clothing, and toys. For some applications, polyamide thermoplastics are coextruded with other polymers.

[0052] In the present description, the term “polyethylene terephthalate” refers to a saturated polyester obtained by the polycondensation of (a) terephthalic acid and ethylene glycol or (b) dimethyl terephthalate and ethylene glycol.

[0053] In the present description, the term “polymer” means a macromolecular compound prepared by polymerizing monomers of the same or different type. The term “polymer” includes homopolymers, copolymers, terpolymers, interpolymers, and so on.

[0054] In the present description, the term “polymer composition” refers to a composition made from or containing a polymer.

[0055] In the present description, the term “polyolefin” is used herein broadly to include polymers such as polyethylene, ethylene-alpha olefin copolymers (EAO), polypropylene, polybutene, and ethylene copolymers having at least about 50 percent by weight of ethylenepolymerized with a lesser amount of a comonomer such as vinyl acetate, and other polymeric resins within the "olefin" family classification.

[0056] Polyolefins can be 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] In the present description, the term “room temperature” refers to a temperature of about 25 degrees Celsius.

[0061] In the present description, the term "spherical” refers to the shape of a particle having the form of a sphere or of one of its segments and have a sphericity’ of at least 0.85. The sphericity’ of a particle is defined as the surface area of a sphere (with the same volume of a given particle) to the surface area of the particle:where Vpis the volume of the particle, and Ap, is the surface area of the particle. A spherical particle will have the sphericity of 1.

[0062] In the present description, the term “substantially spherical in shape” refers to at least 80 %, alternatively at least 85 %, of the particles being spherical.

[0063] In the present description, the term “thermoplastic polymer” means a polymer that softens when exposed to heat and returns to its original condition when cooled to room temperature.

[0064] 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.

[0065] In some embodiments, the present disclosure provides a method for recycling plastic waste including the step of chemically-modifying the plastic waste, thereby reducing selectively the proportion of contaminants immiscible with a microfine PCR / PIR resin, wherein the plastic waste is selected from the group consisting of post-consumer recyclate and postindustrial recy elate.

[0066] 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) chemically-modifying the plastic waste, thereby reducing selectively the proportion of the contaminant immiscible with a microfine PCR / PIR resin made from or containing the polyolefin, preparing the microfine PCR / PIR resin, and yielding a poly olefinic mixture made from or containing the miscible portion of the contaminant and the microfine PCR / PIR resin; and(c) pelletizing the polyolefinic mixture, thereby forming a pelletized resin selected from the group consisting of a pelletized, post-consumer recycled (PCR) resin, a pelletized, post-industrial recycled (PIR) resin, or both.

[0067] 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.

[0068] In some embodiments, the method for recycling plastic waste further includes the steps of:(a.iii) sieving the plastic waste; and(a.iv) separating the plastic waste by particle size.

[0069] 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;(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;(b) chemically-modifying the plastic waste, thereby reducing selectively the proportion of the contaminant immiscible with a microfine PCR / PIR resin made from or containing the polyolefin and yielding a poly olefinic mixture made from or containing the miscible portion of the contaminant and the microfine PCR / PIR resin; and(c) pelletizing the polyolefinic mixture, thereby forming a pelletized resin selected from the group consisting of a pelletized, post-consumer recycled (PCR) resin, a pelletized, post-industrial recycled (PIR) resin, or both.

[0070] 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.

[0071] 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 acry lonitrile butadiene styrene (ABS), calcium carbonate, coffee grounds, diapers, dirt, fillers, food stuffs, glass, grass, labels, metals (including aluminum), nylon, other inorganics, paper, plant stems, polycarbonates, polyethylene terephthalate (PET), other polymers, processing additives, property-imparting additives, rubbers, and wood.

[0072] In some embodiments, the step of chemically-modifying plastic waste includes the steps of (i) admixing a resin-dispersing agent and water to the plastic waste, (ii) agitating the plastic waste, the resin-dispersing agent, and the water at a temperature above the melting point of thePCR / P1R resin and at a pressure for maintaining the water in a liquid state, thereby forming a dispersion, (iii) cooling the dispersion below the melting point of the PCR / PIR resin, thereby deriving microfme particles made from or containing the PCR / PIR resin, and (iv) separating the microfine particles from the aqueous phase in the form of discrete particles. In some embodiments, these steps are referred to as a “microfine process / ’

[0073] In some embodiments, the resin dispersing agent is selected from the group consisting of water soluble block copolymers, water insoluble ionomer polymers, soaps, and detergents. In some embodiments, the water soluble block copolymer is a block copolymer of ethylene oxide and propylene oxide. In some embodiments, the soaps are salts of acids, alternatively lithium behenate. In some embodiments, the soaps are alkali metal soaps of fatty acids in situ during the dispersion process and in the presence of a water-soluble neutral salt. In some embodiments, the fatty acids are selected from the group consisting of stearic acid, oleic acid, palmitic acid, and myristic acid. In some embodiments, the water-soluble neutral salt is selected from the group consisting of sodium chloride and sodium sulfate.

[0074] In some embodiments, the microfine process further includes step (v) separating components of the dispersion based upon particle size, wherein step (iii) yields particles having a size greater than the size of the microfine particles. In some embodiments, the larger particles have a particle size greater than 2000 pm, are non-polyolefinic contaminants, and are separated from the microfine particles.

[0075] In some embodiments, the microfine process is further applied to polymers selected from the group consisting of vinyls, olefin-vinyl copolymers, olefinallyl copolymers, polyamides, acrylics, polystyrenes, cellulosics, polyesters, and fluorocarbons. In some embodiments, the non- polyolefinic, microfine particles have an average particle size from 1 to 2000 pm, alternatively 1- 1000 pm, alternatively 1-100 pm, alternatively 1-50 pm, alternatively 1-20 pm, alternatively 10- 20 pm. with a narrow size distribution, thereby limiting the impact of the non-polyolefinic, microfine particles to the formation of gels or stress points in a resulting matrix or microfine PCR resin.

[0076] In some embodiments, the step of chemically-modifying the plastic waste is applied to the cellulosic components of the plastic waste, including, for example, grass, labels, paper, plant stems, and wood. In some embodiments, the step of chemically-modifying plastic waste further includes the steps of (i) admixing a hydrophobic-treating compound, for reducing the immiscibility of cellulose-based contaminants with the microfine PCR / PIR resin, to the plastic waste, and (ii) reacting the hydrophobic-treating compound with cellulose-based contaminants, with the proviso that the plastic waste is made from or containing cellulose-based contaminants, thereby yieldingtreated, cellulose-based contaminants having greater miscibility with the microfine PCR / P1R resin than the untreated, cellulose-based contaminants. In some embodiments, the step of chemically- modifying plastic waste further includes step (iii) heating the mixture of the hydrophobic-treating compound and the plastic waste to a temperature in the range between 25 degrees Celsius and 100 degrees Celsius, thereby decreasing the reaction time of step (ii).

[0077] In some embodiments, the hydrophobic-treating compound is selected from the group consisting of carboxylic acids, metal salts of carboxylic acids, and castor oil. In some embodiments, the hydrophobic-treating compound is further made from or containing water or another solvent, thereby improving the dispersion of hydrophobic-treating compound.

[0078] In some embodiments, the hydrophobic-treating compound increases adhesion between the PCR / PIR resin and the cellulose-based contaminant. In some embodiments, the hydrophobic-treating compound decreases the size of the cellulose.

[0079] In some embodiments, the step of chemically-modifying the plastic waste is applied to polymeric contaminants in the plastic waste, selected from the group consisting of polyamide and polyethylene terephalate. In some embodiments, the proportion of immiscible polyamide or polyethylene terephalate contaminants is reduced selectively by depolymerization. In some embodiments, the polyamide is nylon 6 or nylon 66.

[0080] In some embodiments, the step of chemically-modifying plastic waste further includes the steps of (i) admixing a depolymerizing reactant, for depolymerizing polymeric contaminants, selected from the group consisting of water, steam, and alcohol to the plastic waste, the PCR / PIR resin, an intermediate composition between the plastic waste and the PCR / PIR resin, or a combination thereof, (ii) reacting the depolymerizing reactant with the polymeric contaminants, thereby depolymerizing polymeric contaminants and converting the polymeric contaminants into chemical compounds that volatilize under the conditions for extrusion or postpelletization of the PCR / PIR resin, and (iii) optionally, volatizing the chemical compounds under the conditions for extrusion or post-pelletization of the PCR / PIR resin.

[0081] In some embodiments, the depolymerization of nylon 6 and nylon 66 is hydrolysis depolymerization, yielding the monomers (a) caprolactam and (b) hexamethylene diamine and adipic acid, respectively. In some embodiments, the depolymerization of polyethylene terephthalate is ydrolysis depolymerization, yielding terephthalic acid and monoethylene glycol monomers, or methanolysis depolymerization, yielding dimethyl terephthalate and monoethylene glycol monomers.

[0082] In some embodiments, the depolymerization occurs in the presence of a catalyst. In some embodiments, the catalyst is selected from the group consisting of phosphotungsic heteropoly acid, lanthanum trisamido catalyst, and zeolite. In some embodiments, the catalyst accelerates the depolymerization of the polymeric contaminants. In some embodiments, the catalyst enables the depolymerization of the polymeric contaminants. In some embodiments, excess reactant serves as a stripping agent for the depolymerization products and other contaminants.

[0083] 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 post-consumer recyclate and post-industrial recyclate, and made from or containing a polyolefin and a contaminant;(b) chemically-modifying the plastic waste, thereby reducing selectively the proportion of the contaminant immiscible with a microfine PCR / PIR resin made from or containing the polyolefin, preparing the microfine PCR / PIR resin, and yielding a polyolefinic mixture made from or containing the miscible portion of the contaminant and the microfine PCR / PIR resin; including the steps of(i) admixing a resin-dispersing agent and water to the plastic waste,(ii) agitating the plastic waste, the resin-dispersing agent, and the water at a temperature above the melting point of the PCR / PIR resin and at a pressure for maintaining the water in a liquid state, thereby forming a dispersion,(iii) cooling the dispersion below the melting point of the PCR / PIR resin, thereby deriving microfine resin particles made from or containing the PCR / PIR resin,(iv) separating the microfine resin particles from the aqueous phase in the form of discrete particles,(v) optionally,(A) admixing a hydrophobic-treating compound, for reducing the immiscibility of cellulose-based contaminants with the microfine PCR / PIR resin, to the plastic waste, and(B) reacting the hydrophobic-treating compound with cellulose-based contaminants, with the proviso that the plastic waste is made from orcontaining cellulose-based contaminants, thereby yielding treated, cellulose-based contaminants having greater miscibility with the microfine PCR / PIR resin than the untreated, cellulose-based contaminants, and(vi) optionally,(A) admixing a depolymerizing reactant, for depolymerizing polymeric contaminants, selected from the group consisting of water, steam, and alcohol to the plastic waste,(B) reacting the depolymerizing reactant with the polymeric contaminants, with the proviso that the plastic waste is made from or containing polymeric contaminants, thereby depolymerizing polymeric contaminants and converting the polymeric contaminants into chemical compounds that volatilize under the conditions for extrusion or postpelletization of the PCR / PIR resin, and(C) optionally, volatizing the chemical compounds under the conditions for extrusion or post-pelletization of the PCR / PIR resin, and(c) pelletizing the polyolefinic mixture, thereby forming a pelletized resin selected from the group consisting of a pelletized, post-consumer recycled (PCR) resin, a pelletized, post-industrial recycled (PIR) resin, or both.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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 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.

[0088] In some embodiments, the resin bears the International Code Council (ICC) Certification.

[0089] 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.

[0090] 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 non- cosmetic-intensive, post consumer recycled resin applications, including agricultural film and trash bags.EXAMPLES

[0091] The following examples are included to demonstrate embodiments. The techniques disclosed in the examples constitute exemplary modes of practice. Changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of this disclosure.

[0092] Reduce Proportion of Immiscible Cellulose-Based Contaminants: Ex. Nos. 1-3

[0093] For the examples, post-consumer recycled bottles in bales are ground and used as plastic waste feedstock. Alternatively, post-consumer HDPE regrind or post-consumer HDPE pellets are used.

[0094] To prepare pellets for Example No. 1, load twenty (20) pounds of the plastic waste feedstock and stearic acid at 5 wt% are fed into a blender. The mixture is blended at room temperature for one hour. Subsequently, the mixture is pelletized on a twin screw extruder with a strand pelletizer.

[0095] To prepare pellets for Example No. 2, load twenty (20) pounds of the plastic waste feedstock and calcium stearate at 5 wt% are fed to the blender. The mixture is blended at room temperature for one hour and then pelletized on a twin screw extruder with a strand pelletizer.

[0096] To prepare pellets for Example No. 3, load twenty (20) pounds of the plastic waste feedstock and castor oil at 5 wt% are fed to the blender. The mixture is blended at room temperature for one hour and then pelletized on a twin screw extruder with a strand pelletizer.

[0097] Physical Properties of Blow-Molded Bottles

[0098] A blow molder is used to prepare 1 -gallon bottles from each set of pellets. The pellets are loaded into a hopper, in an amount to produce 100 bottles with a weight of 155 grams.

[0099] The resulting bottles are compared for crush performance, drop impact, and environmental stress crack resistance (ESCR).

[0100] Crush performance is determined by placing an empty' bottle on flat platens. The distance between the platens is decreased at a rate of 2” / min. The yield point for each set of bottles is recorded.

[0101] Drop impact is determined by filling an empty bottle to capacity with water. The bottle is conditioned to room temperature overnight.

[0102] The Bruceton staircase method is used to determine the F50 drop height for each set. That is, bottles are impact tested at various heights. Specifically, if the bottle does not fail at the initial height, the height is increased incrementally by one foot until failure occurs. After failure has occurred, the height is decreased by the same increment (that is, one foot) and the process is repeated until the samples are utilized. The F50 is then calculated.

[0103] Environmental stress crack resistance (ESCR) is determined by filling each bottle to a third of the bottle’s capacity with a 10% Igepal solution. The partially -filled bottles is placed in an oven at 50°C and then checked daily for failures. The number of days to failure is recorded.

[0104] Test crush resistance by placing empty bottle on flat platens mounted on the Instron. Decrease the distance between the platens at a rate of 2’7min and record the yield point for each set of bottles.

[0105] Microfine PCR Resin: Comp. Ex. No. 4 and Ex. No. 5

[0106] For the examples, post-consumer recycled bottles in bales are ground and used as plastic waste feedstock. Alternatively, post-consumer HDPE regrind or post-consumer HDPE pellets are used.

[0107] To prepare Comparative Example No. 4 , load the following components into a Parr reactor:(a) 300 parts polyethylene,(b) 18 parts block copolymer of ethylene oxide and propylene oxide having a molecular weight of 13,500 and containing 20 percent by weight of propylene oxide and 80 percent by weight of ethylene oxide, and(c) 273 parts of deaerated water.(See Example No. 1, as described in United States Patent No. 3,422,049).

[0108] To prepare Example No. 5 of the microfine PCR resin, load the following components into a Parr reactor:(a) 300 parts plastic waste feedstock,(b) 18 parts block copolymer of ethylene oxide and propylene oxide having a molecular weight of 13,500 and containing 20 percent by weight of propylene oxide and 80 percent by weight of ethylene oxide, and(c) 273 parts of deaerated water.

[0109] To prepare each set of microfine polymer particles, use the following procedure:

[0110] Replace the air in the reactor with nitrogen and heat until the temperature of the mixture reaches 200 degrees Celsius at a pressure of 235 psi (1.62 MPA). Stir the mixture at a rate of 8,000 to 10.000 r.p.m. for 8 to 10 minutes, thereby forming a dispersion. Cool the reactor to room temperature. Vent the reactor, thereby reducing the pressure. Dilute the dispersion with an equal volume of water. Filter the dispersion. Wash the resulting composition with water. Dry the perci pitant for 4 hours at 60 C.[OHl] Measure the particle size of the resulting microfine composition particles, using a Malvern laser particle size analyzer. The resulting particles will have an average particle size of about 3 microns and a spherical shape.

[0112] Pelletize the microfine composition particles on a twin screw extruder with a strand pelletizer.

[0113] Physical Properties of Blow-Molded Bottles

[0114] A blow molder is used to prepare 1-gallon bottles from each set of pellets. The pellets are loaded into a hopper, in an amount to produce 100 bottles with a weight of 155 grams.

[0115] The resulting bottles are compared for crush performance, drop impact, and environmental stress crack resistance (ESCR).

[0116] Crush performance is determined by placing an empty bottle on flat platens. The distance between the platens is decreased at a rate of 2” / min. The yield point for each set of bottles is recorded.

[0117] Drop impact is determined by filling an empty bottle to capacity with water. The bottle is conditioned to room temperature overnight.

[0118] The Bruceton staircase method is used to determine the F50 drop height for each set. That is, bottles are impact tested at various heights. Specifically, if the bottle does not fail at the initial height, the height is increased incrementally by one foot until failure occurs. After failure has occurred, the height is decreased by the same increment (that is, one foot) and the process is repeated until the samples are utilized. The F50 is then calculated.

[0119] Environmental stress crack resistance (ESCR) is determined by filling each bottle to a third of the bottle’s capacity with a 10% Igepal solution. The partially -filled bottles is placed in an oven at 50°C and then checked daily for failures. The number of days to failure is recorded.

[0120] Test crush resistance by placing empty bottle on flat platens mounted on the Instron. Decrease the distance between the platens at a rate of 2’7min and record the yield point for each set of bottles.

[0121] It should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of this disclosure as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of the ordinary skill in the art will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform the same function or achieve the same result as the corresponding embodiments described herein can be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

CLAIMSWhat is claimed is:

1. A method for recycling plastic waste comprising the step of: chemically-modifying the plastic waste, thereby reducing selectively the proportion of contaminants immiscible with a microfine PCR / PIR resin, wherein the plastic waste is selected from the group consisting of post-consumer recyclate and post-industrial recy elate.

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 made from or containing a polyolefin and a contaminant;(b) chemically-modifying the plastic waste, thereby reducing selectively the proportion of the contaminant immiscible with a microfine PCR / PIR resin made from or containing the polyolefin, preparing the microfine PCR / PIR resin, and yielding a poly olefinic mixture made from or containing the miscible portion of the contaminant and the microfine PCR / PIR resin; including the steps of(i) admixing a resin-dispersing agent and water to the plastic waste,(ii) agitating the plastic waste, the resin-dispersing agent, and the water at a temperature above the melting point of the PCR / PIR resin and at a pressure for maintaining the water in a liquid state, thereby forming a dispersion,(iii) cooling the dispersion below the melting point of the PCR / PIR resin, thereby deriving microfine resin particles made from or containing the PCR / PIR resin,(iv) separating the microfine resin particles from the aqueous phase in the form of discrete particles,(v) optionally,(A) admixing a hydrophobic-treating compound, for reducing the immiscibility of cellulose-based contaminants with the microfine PCR / PIR resin, to the plastic waste, and(B) reacting the hydrophobic-treating compound with cellulose-based contaminants, with the proviso that the plastic waste is made from or containing cellulose-based contaminants, thereby yielding treated, cellulose-based contaminants having greater miscibility with the microfine PCR / PIR resin than the untreated, cellulose-based contaminants, and(vi) optionally,(A) admixing a depolymerizing reactant, for depolymerizing polymeric contaminants, selected from the group consisting of water, steam, and alcohol to the plastic waste,(B) reacting the depolymerizing reactant with the polymeric contaminants, with the proviso that the plastic waste is made from or containing polymeric contaminants, thereby depolymerizing polymeric contaminants and converting the polymeric contaminants into chemical compounds that volatilize under the conditions for extrusion or postpelletization of the PCR / PIR resin, and(C) optionally, volatizing the chemical compounds under the conditions for extrusion or post-pelletization of the PCR / PIR resin, and(c) pelletizing the polyolefinic mixture, thereby forming a pelletized resin selected from the group consisting of a pelletized, post-consumer recycled (PCR) resin, a pelletized, post-industrial recycled (PIR) resin, or both.

3. The method for recycling plastic waste of Claim 2, wherein the resin dispersing agent is selected from the group consisting of water soluble block copolymers, water insoluble ionomer polymers, soaps, and detergents.

4. The method for recycling plastic waste of Claim 2, further comprising step (iii.a) separating components of the dispersion based upon particle size, wherein step (iii) also yields particles having a size greater than the size of the microfine resin particles.

5. The method for recycling plastic waste of Claim 2, wherein the microfine PCR / PIR resin has an average particle size from 1-100 pm.

6. The method for recycling plastic waste of Claim 2, wherein the hydrophobic-treating compound is selected from the group consisting of carboxylic acids, metal salts of carboxylic acids, and castor oil.

7. The method for recycling plastic waste of Claim 2, wherein a catalyst is admixed to the depolymerizing reactant and the catalyst is selected from the group consisting of phosphotungsic heteropoly acid, lanthanum trisamido catalyst, and zeolite.

8. 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;(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,(b) chemically-modifying the plastic waste, thereby reducing selectively the proportion of the contaminant immiscible with a microfme PCR / PIR resin made from or containing the polyolefin, preparing the microfme PCR / PIR resin, and yielding a poly olefinic mixture made from or containing the miscible portion of the contaminant and the microfme PCR / PIR resin; including the steps of(i) admixing a resin-dispersing agent and water to the plastic waste,(ii) agitating the plastic waste, the resin-dispersing agent, and the water at a temperature above the melting point of the PCR / PIR resin and at a pressure for maintaining the water in a liquid state, thereby forming a dispersion,(iii) cooling the dispersion below the melting point of the PCR / PIR resin, thereby deriving microfme resin particles made from or containing the PCR / PIR resin,(iv) separating the microfme resin particles from the aqueous phase in the form of discrete particles,(v) optionally,(A) admixing a hydrophobic-treating compound, for reducing the immiscibility of cellulose-based contaminants with the microfme PCR / PIR resin, to the plastic waste, and(B) reacting the hydrophobic-treating compound with cellulose-based contaminants, with the proviso that the plastic waste is made from or containing cellulose-based contaminants, thereby yielding treated, cellulose-based contaminants having greater miscibility with the microfine PCR / PIR resin than the untreated, cellulose-based contaminants, and(vi) optionally,(A) admixing a depolymerizing reactant, for depolymerizing polymeric contaminants, selected from the group consisting of water, steam, and alcohol to the plastic waste,(B) reacting the depolymerizing reactant with the polymeric contaminants, with the proviso that the plastic waste is made from or containing polymeric contaminants, thereby depolymerizing polymeric contaminants and converting the polymeric contaminants into chemical compounds that volatilize under the conditions for extrusion or postpelletization of the PCR / PIR resin, and(C) optionally, volatizing the chemical compounds under the conditions for extrusion or post-pelletization of the PCR / PIR resin, and(c) pelletizing the polyolefinic mixture, thereby forming a pelletized resin selected from the group consisting of a pelletized, post-consumer recycled (PCR) resin, a pelletized, post-industrial recycled (PIR) resin, or both.

9. 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.

10. The method for recycling plastic waste of Claim 9, 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.

11. The method for recycling plastic waste of Claim 1, wherein the microfine PCR / PIR resin is selected from the group consisting of polyethylene and polypropylene.

12. A pelletized, post-consumer recycled resin comprising (a) PCR / P1R resin selected from the group consisting of polyethylene and polypropylene and (b) contaminants, prepared via chemically -modifying the plastic waste and thereby reducing selectively the proportion of contaminants immiscible with the PCR / PIR resin.

13. An article of manufacture comprising the post-consumer recycled resin of Claim 12.

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