Compounds and products utilizing recycled cross-linked polyethylene and methods for producing them

Abstract

Provided herein are recycled or post-production cross-linked polyethylene (PEX)- based compounds, products and methods for producing them.

Description

[0001] COMPOUNDSAND PRODUCTS UTILIZING RECYCLED CROSS-LINKED POLYETHYLENE AND METHODS FOR PRODUCING THEM

[0002] FIELD OF THE INVENTION

[0003] Provided herein are recycled or post-production cross-linked polyethylene (PEX)- based compounds, products and methods for producing them.

[0004] BACKGROUND OF THE INVENTION

[0005] Cross-linked polyethylene (PEX) has become a preferred option for use in plumbing applications, solar panels, wires, and cables, because of its flexibility, resistance to heat and cold, and since it does not corrode.

[0006] Since PEX, as the name implies, is cross-linked, it cannot be melted down, and therefore direct recycling is impossible. In the past, PEX could only be effectively recycled if the cross-linking points were decomposed. Such a process, however, is not cost effective. With the popularity of PEX and the growing awareness of the need for green products, the demand for PEX recycling is likely to rise.

[0007] Therefore, there is a need for re-utilization of recycled or post-production cross-linked polyethylene.

[0008] SUMMARY OF THE INVENTION

[0009] There is provided herein, in accordance with some embodiments, a thermoplastic compound including: about 50 %wt / wt to about 85 %wt / wt recycled or post-production cross-linked polyethylene (PEX); and about 15 %wt / wt to about 50 %wt / wt of at least one polymeric binder, wherein the thermoplastic compound has a melt flow index (MFI), as measured at 190°C and 2.16 Kg, ranging between about 0.01 to about 10 g / 10 min. There is further provided herein, in accordance with some embodiments, a recycled or post-production PEX- based article of manufacture including a thermoplastic compound, thermoplastic compound including: about 50 %wt / wt to about 85 %wt / wt recycled or post-production cross-linked polyethylene (PEX); and about 15 %wt / wt to about 50 %wt / wt of at least one polymeric binder. According to some embodiments, the thermoplastic compound has a melt flow index (MFI), as measured at 190°C and 2.16 Kg, ranging between about 0.01 to about 10 g / 10 min.

[0010] According to some embodiments, the PEX may be shredded, granulated, pulverized, or any combination thereof.

[0011] According to some embodiments, at least one of the polymeric binders may comprise a polyolefin. According to some embodiments, the polyolefin may be selected from the group consisting of: polyethylene, polypropylene homopolymer, polypropylene copolymer, polybutadiene, polyisobutylene, polymethylpentene, cyclo-olefin copolymer, and any combination thereof. Each possibility is a separate embodiment.

[0012] According to some embodiments, the polyethylene may be high density polyethylene.

[0013] According to some embodiments, the thermoplastic compound may include at least one antioxidant in an amount between about 0.1 %wt / wt to about 2 %wt / wt. According to some embodiments, at least one antioxidant may be a sterically hindered phenolic compound, an aromatic phosphite compound, or any combination thereof. Each possibility is a separate embodiment.

[0014] According to some embodiments, the sterically hindered phenolic compound may be selected from the group consisting of butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tertiary-butylhydroquinone (TBHQ), 3,4,5-trihydroxybenzoic acid, catechin, epicatechin, quercetin, kaempferol, gallic acid, caffeic acid, coumaric acid, coumarine, and any combination thereof. Each possibility is a separate embodiment.

[0015] According to some embodiments, the aromatic phosphite compound may be selected from the group consisting of tetrakis(2,4-di -tert-butyl- phenyl)[l,l-biphenyl]-4,4’- diylbisphosphonite, bis(2,6-di-ter-butyl-4-methyl-phenyl)pentaerythritol-diphosphite, tri- (nonyl-phenyl) phosphite, tris(2,4-ditert-butylphenyl) phosphite, bis(2,4-di-t- butylphenyl)pentaerythritol diphosphite, tetraphenyl dipropylene glycol diphosphate, and any combination thereof. Each possibility is a separate embodiment. According to some embodiments, the thermoplastic compound may be in the form of powder, particles, pellets, or any combination thereof. Each possibility is a separate embodiment.

[0016] According to some embodiments, the average diameter of the powder may range between about 150 pm to about 500 pm. According to some embodiments, the average diameter of the particle may range between about 3 mm to about 14 mm. According to some embodiments, the longest dimension of the pellets may range between about 3 to about 6 mm.

[0017] According to some embodiments, the thermoplastic compound may have a melt flow index (MFI), as measured at 190 °C and 2.16 Kg, ranging between about 0.01 g / lOmin to about 10 g / lOmin (for example, about 4 g / lOmin).

[0018] According to some embodiments, the ratio of recycled or post-production PEX to binder may range between about 4: 1 to about 1 : 1.

[0019] According to some embodiments, the recycled or post-production PEX may be chemically cross-linked polyethylene, thermally cross-linked polyethylene, irradiation crosslinked polyethylene, or any combination thereof. Each possibility is a separate embodiment.

[0020] According to some embodiments, the recycled or post-processed PEX may be derived from recycled PEX pipes or fittings, post-processed PEX material, PEX cable insulation, PEX foam, or any combination thereof. Each possibility is a separate embodiment.

[0021] Some embodiments may relate to a method for the preparation of a thermoplastic compound, the method comprising: shredding, granulating and / or pulverizing recycled or post-production cross-linked polyethylene (PEX) to achieve PEX powder; mixing about 50 %wt / wt to about 85 %wt / wt of the PEX powder with about 15 %wt / wt to about 50 %wt / wt of at least one polymeric binder to obtain a thermoplastic compound, wherein the thermoplastic compound has a melt flow index (MFI), as measured at 190 °C and 2.16 Kg, ranging between about 0.01 to about 10 g / lOmin.

[0022] According to some embodiments, the shredding, granulation and pulverizing may be carried out in a rotary blades type shredder, high speed rotating blades cylinder type granulator, rotary discs pulverizer, twin-roll cracker, refiner mill, or any combination thereof. Each possibility is a separate embodiment. According to some embodiments, the shredding, granulation and pulverizing may be carried out at room temperature or at temperatures below -80°C e.g., by means of a cryogenic system.

[0023] According to some embodiments, the mixing may be carried out in a co-rotating twin- screw type compounding extruder or single screw extruder recycling unit.

[0024] According to some embodiments, at least one antioxidant may be added to the thermoplastic compound. According to some embodiments, at least one antioxidant may be a sterically hindered phenolic compound, an aromatic phosphite compound, or any combination thereof. Each possibility is a separate embodiment.

[0025] According to some embodiments, the sterically hindered phenolic compound may be selected from the group consisting of butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tertiary-butylhydroquinone (TBHQ), 3,4,5-trihydroxybenzoic acid, catechin, epicatechin, quercetin, kaempferol, gallic acid, caffeic acid, coumaric acid, coumarine, and any combination thereof. Each possibility is a separate embodiment.

[0026] According to some embodiments, the aromatic phosphite compound may be selected from the group consisting of tetrakis(2,4-di -tert-butyl- phenyl)[l,l-biphenyl]-4,4’- diylbisphosphonite, bis(2,6-di-ter-butyl-4-methyl- phenyl)pentaerythritol-diphosphite, tri- (nonyl-phenyl) phosphite, tris(2,4-ditert-butylphenyl) phosphite, bis(2,4-di-t- butylphenyl)pentaerythritol diphosphate, tetraphenyl dipropylene glycol diphosphate, and any combination thereof. Each possibility is a separate embodiment.

[0027] According to some embodiments, the ratio of recycled PEX powder to binder ranges between about 4: 1 to about 1 : 1.

[0028] Some embodiments relate to a method of producing a recycled or post-production PEX- based article of manufacture, the method comprising: heating the thermoplastic compound of any one of claims 1-15 or the thermoplastic compound produced by the method of any one of claims 16-26 with a thermoplastic polymeric mixture to form a melt, wherein a ratio of recycled or post-production cross-linked polyethylene (PEX) powder to total compound matrix in the melt ranges from about 1 :20 to about 1 : 1.5; and extruding, injecting, or compression molding the melt under predetermined pressure and temperature conditions, to produce an article of manufacture from the thermoplastic compound having a wall or section thereof with a thickness of at least about 2 mm. According to some embodiments, the additional thermoplastic polymeric mixture may comprise one or more polyolefins selected from the group consisting of polyethylene, polypropylene homopolymer, polypropylene copolymer, polybutadiene, polyisobutylene, polymethylpentene, cyclo-olefin copolymer or any combination thereof. Each possibility is a separate embodiment.

[0029] According to some embodiments, the predetermined pressure for injection may range between about 600 to about 2,500 bar. According to some embodiments, the predetermined temperature for injection may range between about 190°C to about 280°C.

[0030] According to some embodiments, the predetermined pressure for extrusion may range between about 70 to about 150 bar. According to some embodiments, the predetermined temperature for extrusion may range between about 200°C to about 250°C.

[0031] According to some embodiments, the predetermined pressure for compression molding may range between about 14 to about 245 bar. According to some embodiments, the predetermined temperature for compression molding may range between about 190°C to about 280°C.

[0032] According to some embodiments, the predetermined temperature for extrusion, injection or compression molding may be the temperature of the barrel.

[0033] According to some embodiments, the PEX-based article of manufacture may have a wall or section thereof with a thickness ranging between about 2 mm to about 5 cm.

[0034] According to some embodiments, the method may include foaming the melt prior to extrusion, injection, or compression molding. According to some embodiments, a foaming agent may be added to the melt. According to some embodiments, the foaming agent is selected from the group consisting of sodium bicarbonate, sodium carbonate, potassium bicarbonate and any combination thereof. Each possibility is a separate embodiment.

[0035] According to some embodiments, the method may include adding at least one antioxidant to the melt prior to extrusion, injection, or compression molding. Each possibility is a separate embodiment.

[0036] According to some embodiments, at least one antioxidant may be a sterically hindered phenolic compound, an aromatic phosphite compound, or any combination thereof. Each possibility is a separate embodiment. According to some embodiments, the sterically hindered phenolic compound is selected from the group consisting of butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tertiary-butylhydroquinone (TBHQ), 3,4,5-trihydroxybenzoic acid, catechin, epicatechin, quercetin, kaempferol, gallic acid, caffeic acid, coumaric acid, coumarine, and any combination thereof. Each possibility is a separate embodiment.

[0037] According to some embodiments, the aromatic phosphite compound is selected from the group consisting of tetrakis(2, 4-di -tert-butyl -phenyl)[ 1,1 -biphenyl]-4, 4’- diylbisphosphonite, bis(2,6-di-ter-butyl-4-methyl- phenyl)pentaerythritol-diphosphite, tri- (nonyl-phenyl) phosphite, tris(2,4-ditert-butylphenyl) phosphite, bis(2,4-di-t- butylphenyl)pentaerythritol diphosphate, tetraphenyl dipropylene glycol diphosphate, and any combination thereof. Each possibility is a separate embodiment.

[0038] According to some embodiments, the method may be for use in preparing water pipes, sewer trenches, habitats for domestic animals and fish, molds for construction (concrete), water tanks, box pallets, flat pallets, containers, trash bins, automotive parts, tiles, extruded profiles, toys, or any combination thereof. Each possibility is a separate embodiment.

[0039] According to some embodiments, an article of manufacture produced according to a method as described herein.

[0040] BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Some embodiments of the disclosure are described herein with reference to the accompanying figures. The description, together with the figures, makes apparent to a person having ordinary skill in the art how some embodiments may be practiced. The figures are for the purpose of illustrative description and no attempt is made to show structural details of an embodiment in more detail than is necessary for a fundamental understanding of the disclosure. For the sake of clarity, some objects depicted in the figures are not to scale.

[0042] In the Figures:

[0043] Fig. 1 is a flowchart of a flow chart of a process for producing recycled cross-linked polyethylene, in accordance with some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0044] Some embodiments of the present invention relate to products and methods for producing and utilizing recycled cross-linked polyethylene (PEX).

[0045] As used herein, according to some embodiments, the terms "cross-linked polyethylene" and "PEX" are used interchangeably, and may refer to a polyethylene material which has undergone a change in molecular structure using a chemical or a physical process whereby the polymer chains are chemically linked. There are various types of polyethylene cross-linking: peroxide cross-linking, radiation cross-linking, thermal cross-linking, and silane cross-linking. Crosslinking of polyethylene results in improved properties such as elevated temperature, strength, and performance, chemical resistance, and resistance to slow crack growth.

[0046] As used herein, according to some embodiments, the term "recycled cross-linked polyethylene" may refer to cross-linked polyethylene which was previously used for a particular purpose and is now being repurposed and / or reprocessed for a new purpose, e.g., to produce new articles of manufacture. As used herein, according to some embodiments, the term "post-production cross-linked polyethylene" may refer to off-cuts of cross-linked polyethylene, from the manufacturing site and / or from users, which were produced but not used.

[0047] According to some embodiments, the recycled cross-linked polyethylene and / or postproduction cross-linked polyethylene powder may be chemically cross-linked polyethylene, thermally cross-linked polyethylene, irradiation cross-linked polyethylene, or any combination thereof. According to some embodiments, the recycled cross-linked polyethylene and / or postprocessed cross-linked polyethylene may be derived from recycled cross-linked polyethylene pipes, fittings, post-processed cross-linked polyethylene material, cross-linked polyethylene cable insulation, cross-linked polyethylene foam, or any combination thereof.

[0048] As used herein, according to some embodiments, the term "thermoplastic compound" may refer to a base material including resins, thermoplastic polymer(s) mixed with a nonthermoplastic (e.g., thermoset) component to produce material having thermoplastic performance properties (e.g., elastic modulus, impact, bending, etc.). According to some embodiments, the term "thermoplastic compound" may refer to any polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling. According to some embodiments, the term “compounding” may refer to a process of preparing plastic formulations by mixing and / or blending polymers (and optionally additives) in a molten state to achieve the desired characteristics. Compounding may enhance the properties of base polymers by adding other materials to them.

[0049] Some embodiments relate to a product and a method for producing a thermoplastic compound which may comprise recycled cross-linked polyethylene and / or post-production cross-linked polyethylene. According to some embodiments, the thermoplastic compound may have a melt flow index (MFI), as measured at 190°C and 2.16 Kg, ranging between about 0.01 g / lOmin to about 10 g / lOmin, between about 0.01 g / lOmin to about 8 g / lOmin, between about 0.01 g / lOmin to about 6 g / lOmin, or between about 0.01 g / lOmin to about 4 g / lOmin. Each possibility is a separate embodiment.

[0050] According to some embodiments, the recycled cross-linked polyethylene and / or postproduction cross-linked polyethylene may be shredded, ground, granulated, pulverized, powdered, or any combination thereof. Each possibility is a separate embodiment. The recycled cross-linked polyethylene and / or post-production cross-linked polyethylene may be in the form of a powder, granules, pellets and / or particles. Each possibility is a separate embodiment.

[0051] According to some embodiments, the average longest dimension and / or average diameter of the recycled cross-linked polyethylene and / or post-production cross-linked polyethylene may be in the range between about 100 pm to about 500 pm, or between about 500 pm to about 1,500 pm. Each possibility is a separate embodiment. Preferably, the average longest dimension and / or average diameter of the recycled cross-linked polyethylene and / or post-production cross-linked polyethylene may be about 60-300 pm.

[0052] According to some embodiments, the thermoplastic compound may include recycled cross-linked polyethylene and / or post-production cross-linked polyethylene in an amount ranging between about 20% wt / wt to about 95% wt / wt, between about 30% wt / wt to about 90% wt / wt, between about 40% wt / wt to about 85% wt / wt, between about 50% wt / wt to about 85% wt / wt, between about 60% wt / wt to about 75% wt / wt. Each possibility is a separate embodiment. Optionally, the recycled cross-linked polyethylene and / or post-production crosslinked polyethylene may be shredded, granulated and / or pulverized.

[0053] According to some embodiments, the thermoplastic compound may include one or more additional polymers. According to some embodiments, the thermoplastic compound may include one or more binders. According to some embodiments, the one or more binders may include polymeric material, e.g., polyolefins. According to some embodiments, the one or more binders may be selected from the group consisting of: polyethylene, polypropylene homopolymers, polypropylene copolymers, polybutadiene, polyisobutylene, polymethylpentene, cyclo-olefin copolymer, and any combination thereof. Each possibility is a separate embodiment. Preferably, the binder is polyethylene, most preferably the binder is high density polyethylene.

[0054] According to some embodiments, the thermoplastic compound may include one or more binders in an amount ranging between about 5% wt / wt to about 60% wt / wt, between about 10% wt / wt to about 55% wt / wt, between about 15% wt / wt to about 50% wt / wt, or between about 20% wt / wt to about 40% wt / wt. Each possibility is a separate embodiment.

[0055] According to some embodiments, the thermoplastic compound may include a ratio of recycled cross-linked polyethylene and / or post-production cross-linked polyethylene to binder in the range between about 6: 1 to about 1 : 1, between about 4: 1 to about 1 : 1, or between about 3: 1 to about 1 : 1. Each possibility is a separate embodiment.

[0056] According to some embodiments, the thermoplastic compound may include one or more antioxidants. According to some embodiments, the thermoplastic compound may include a range between about 0.5 %wt / wt to about 1.5 %wt / wt, or between about 0.5 % wt / wt to about 1 %wt / wt of one or more antioxidants. Each possibility is a separate embodiment.

[0057] According to some embodiments, the one or more antioxidants may be a sterically hindered phenolic compound, an aromatic phosphite compound, and any combination thereof.

[0058] According to some embodiments, a sterically hindered phenolic compound may be selected from the group consisting of butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tertiary-butylhydroquinone (TBHQ), 3,4,5-trihydroxybenzoic acid, catechin, epicatechin, quercetin, kaempferol, gallic acid, caffeic acid, coumaric acid, coumarine, and any combination thereof. Each possibility is a separate embodiment.

[0059] According to some embodiments, an aromatic phosphite compound may be selected from the group consisting of tetrakis(2, 4-di -tert-butyl -phenyl)[ 1,1 -biphenyl]-4, 4’- diylbisphosphonite, bis(2,6-di-ter-butyl-4-methyl-phenyl)pentaerythritol-diphosphite, tri- (nonyl-phenyl) phosphite, tris(2,4-ditert-butylphenyl) phosphite, bis(2,4-di-t-butyl- phenyl)pentaerythritol diphosphite, tetraphenyl dipropylene glycol diphosphate, and any combination thereof. Each possibility is a separate embodiment.

[0060] According to some embodiments, the thermoplastic compound may be produced in the form of powder, particles, pellets, and any combination thereof. Each possibility is a separate embodiment. According to some embodiments, the thermoplastic compound may have a longest dimension or diameter ranging between about 150 gm to about 500 gm for a powder, between about 3 mm to about 14 mm for particles, and between about 3 mm to about 6 mm for pellets. Each possibility is a separate embodiment.

[0061] According to some embodiments, the thermoplastic compound may be prepared by shredding, granulation and / or pulverizing the recycled cross-linked polyethylene and / or postproduction cross-linked polyethylene to achieve a cross-linked polyethylene powder, and mixing the powder with one or more polymeric binders.

[0062] According to some embodiments, the shredding, granulation and / or pulverizing the recycled cross-linked polyethylene and / or post-production cross-linked polyethylene may be carried out in a rotary blades type shredder, high speed rotating blades cylinder type granulator, rotary discs pulverizer, twin-roll cracker, refiner mill, or any combination thereof. Each possibility is a separate embodiment. The shredding, granulation and pulverizing may be carried out at room temperature or at a temperature of -80°C or below, e.g., by means of a cryogenic system.

[0063] According to some embodiments, the mixing may be carried out in a co-rotating twin- screw type compounding extruder or single screw extruder recycling unit.

[0064] According to some embodiments, one or more antioxidants may be added to the mixture.

[0065] According to some embodiments, a recycled or post-production PEX-based article of manufacture may be produced from the thermoplastic compound. According to some embodiments, the thermoplastic compound may be used in the preparation of water pipes, sewer trenches, habitats for domestic animals and fish, molds for construction (e.g., concrete molds, etc.), water tanks, box pallets, flat pallets, containers of any kind (e.g., trash bins), automotive parts, tiles, extruded profiles, toys, or any combination thereof. Each possibility is a separate embodiment.

[0066] Some embodiments relate to a method of producing a recycled or post-production PEX- based article of manufacture comprising: heating the thermoplastic compound with an additional thermoplastic polymeric mixture to form a melt; extrusion, injection, compression molding or thermoforming the melt under predetermined pressure and temperature conditions to produce an article of manufacture.

[0067] According to some embodiments, the ratio of recycled or post-production cross-linked polyethylene powder to the total compound matrix in the melt may range between about 1 :20 to about 1 : 1.5; between about 1 :20 to about 1 :2, between about 1 : 15 to about 1 :2, or between about 1 : 15 to about 1 :2 Each possibility is a separate embodiment.

[0068] According to some embodiments, the additional thermoplastic polymeric mixture may include one or more polyolefins selected from the group consisting of polyethylene, polypropylene homopolymer, polypropylene copolymer, polybutadiene, polyisobutylene, polymethylpentene, cyclo-olefin copolymer or any combination thereof. Each possibility is a separate embodiment.

[0069] According to some embodiments, the method may include foaming the melt prior to extrusion, injection, compression molding. Optionally, the extrusion may be followed by thermoforming. According to some embodiments, the foaming may include adding one or more foaming agents to the mixture. According to some embodiments, the foaming agent may be selected from the group consisting of sodium bicarbonate, sodium carbonate, potassium bicarbonate and any combination thereof. Each possibility is a separate embodiment.

[0070] According to some embodiments, the foaming agent may be added to the thermoplastic compound in an amount in the range between about 0.3 %wt / wt to about 2 %wt / wt, between about 0.3 %wt / wt to about 1 %wt / wt, between about 1 %wt / wt to about 2 %wt / wt of one or more foaming agents. Each possibility is a separate embodiment.

[0071] According to some embodiments, the method may include adding one or more antioxidant to the melt prior to extrusion, injection, compression molding. According to some embodiments, the one or more antioxidants may be a sterically hindered phenolic compound, an aromatic phosphite compound, and any combination thereof.

[0072] According to some embodiments, a sterically hindered phenolic compound may be selected from the group consisting of butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tertiary-butylhydroquinone (TBHQ), 3,4,5-trihydroxybenzoic acid, catechin, epicatechin, quercetin, kaempferol, gallic acid, caffeic acid, coumaric acid, coumarine, and any combination thereof. Each possibility is a separate embodiment.

[0073] According to some embodiments, an aromatic phosphite compound may be selected from the group consisting of tetrakis(2, 4-di -tert-butyl -phenyl)[ 1,1 -biphenyl]-4, 4’- diylbisphosphonite, bis(2,6-di-ter-butyl-4-methyl-phenyl)pentaerythritol-diphosphite, tri- (nonyl-phenyl) phosphite, tris(2,4-ditert-butylphenyl) phosphite, bis(2,4-di-t-butyl- phenyljpentaerythritol diphosphite, tetraphenyl dipropylene glycol diphosphate, and any combination thereof. According to some embodiments, the article of manufacture may have a wall or section thereof with a thickness of at least about 1 mm, preferably at least about 2 mm, preferably at least about 3 mm or at least about 5 mm. Each possibility is a separate embodiment. According to some embodiments, the article of manufacture may have a wall or section thereof with a thickness ranging between about 1 mm to about 250 mm, between about 2 mm to about 200 mm, or between about 3 mm to about 150 mm. Each possibility is a separate embodiment.

[0074] According to some embodiments, the predetermined pressure for injection may be in the range between about 600 bar to about 2,500 bar, between about 700 bar to about 2,000 bar or between about 1,000 bar to about 1,500 bar. Each possibility is a separate embodiment.

[0075] According to some embodiments, the predetermined temperature for injection may be in the range between about 150°C to about 300°C, between about 190°C to about 280°C, or between about 200°C to about 250°C. Each possibility is a separate embodiment.

[0076] According to some embodiments, the predetermined pressure for extrusion may be in the range between about 50 bar to about 200 bar, between about 70 bar to about 150 bar, or between about 80 bar to about 100 bar. Each possibility is a separate embodiment.

[0077] According to some embodiments, the predetermined temperature for extrusion may be in the range between about 150°C to about 300°C, between about 200°C to about 250°C, or between about 210°C to about 230°C. Each possibility is a separate embodiment.

[0078] According to some embodiments, the predetermined pressure for compression molding may be in the range between about 14 bar to about 245 bar.

[0079] According to some embodiments, the predetermined temperature for compression molding may be in the range between about 150°C to about 300°C, between about 190°C to about 280°C, or between about 200°C to about 250°C. Each possibility is a separate embodiment.

[0080] According to some embodiments, the predetermined pressure for thermoforming may be in the range between about 0.3 bar to about 15 bar.

[0081] According to some embodiments, the predetermined temperature for thermoforming may be in the range between about 180°C to about 230°C.

[0082] According to some embodiments, the predetermined temperature for extrusion, injection, compression molding or thermoforming may be the temperature of the melt or the barrel. According to some embodiments, an article of manufacture may be produced by this method.

[0083] Accordingly, this invention is not to be limited by the embodiments as described, which are given by way of example only and not by way of limitation.

[0084] Reference is now made to Fig. 1 which is a flow chart of a process for producing recycled cross-linked polyethylene, in accordance with some embodiments. According to some embodiments, in process 100 recycled and / or post-production cross-linked polyethylene (PEX) 102 undergoes a processing step 103, which includes shredding 104, granulation 106, and / or pulverizing 108 to produce processed PEX 105. Processed PEX 105 may then undergo (arrow 109) a compounding step 114. In compounding step 114 (thermoplastic compound production), a polymer binder 110, and optionally also an antioxidant 112, are added to processed PEX 105 to produce a thermoplastic compound 116 ready for post-processing. Optionally, a foaming agent 118, an antioxidant 120, polymer binder 122, additional processed PEX 105 (preferably, pulverized Recycled and / or post-production cross-linked polyethylene 108), or any combination thereof, may be added to the thermoplastic compound 116. Thermoplastic compound 116 can then undergo post processing 107 (for example, by injection molding 124, compression molding 128, or extrusion 126 optionally followed by subsequent thermoforming 130) to produce an article of manufacture.

[0085] Alternatively, (as depicted by arrow 111) processed PEX 105 may be combined directly with polymer binder 122 (without a compounding stage) and optionally with foaming agent 118 and / or antioxidant 120, and undergo post processing 107 (for example, by injection molding 124, compression molding 128, or extrusion 126 optionally followed by subsequent thermoforming 130) to produce an article of manufacture.

[0086] It is expected that during the life of a patent maturing from this application many relevant building technologies, artificial intelligence methodologies, computer user interfaces, image capture devices will be developed and the scope of the terms for design elements, analysis routines, user devices is intended to include all such new technologies a priori .

[0087] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein may be used in the practice or testing of embodiments of the invention, exemplary methods and / or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting .

[0088] The terms "comprises", "comprising", "includes", "including", “having” and their conjugates mean "including but not limited to

[0089] The term “consisting of’ means “including and limited to .”

[0090] The term "consisting essentially of' means that the composition, method or structure may include additional ingredients, steps and / or parts, but only if the additional ingredients, steps and / or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure .

[0091] As used herein, the term “about” may be used to specify a value of a quantity or parameter (e.g., the length of an element) to within a continuous range of values in the neighborhood of (and including) a given (stated) value. According to some embodiments, “about” may specify the value of a parameter to be between 80 % and 120 % of the given value .

[0092] Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range .

[0093] Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging / ranges between” a first indicate number and a second indicate number and “ranging / ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween .

[0094] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. In case of conflict, the patent specification, including definitions, governs. As used herein, the indefinite articles “a” and “an” mean “at least one” or “one or more” unless the context clearly dictates otherwise . It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the disclosure. No feature described in the context of an embodiment is to be considered an essential feature of that embodiment, unless explicitly specified as such.

[0095] Although steps of methods according to some embodiments may be described in a specific sequence, methods of the disclosure may include some or all of the described steps carried out in a different order. A method of the disclosure may include a few of the steps described or all of the steps described. No particular step in a disclosed method is to be considered an essential step of that method, unless explicitly specified as such.

[0096] Although the disclosure is described in conjunction with specific embodiments thereof, it is evident that numerous alternatives, modifications and variations that are apparent to those skilled in the art may exist. Accordingly, the disclosure embraces all such alternatives, modifications and variations that fall within the scope of the appended claims. It is to be understood that the disclosure is not necessarily limited in its application to the details of construction and the arrangement of the components and / or methods set forth herein. Other embodiments may be practiced, and an embodiment may be carried out in various ways.

[0097] The phraseology and terminology employed herein are for descriptive purpose and should not be regarded as limiting. Citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the disclosure. Section headings are used herein to ease understanding of the specification and should not be construed as necessarily limiting.

Claims

CLAIMSWhat is claimed is:

1. A thermoplastic compound comprising: about 50 %wt / wt to about 85 %wt / wt recycled or post-production cross-linked polyethylene (PEX); and about 15 %wt / wt to about 50 %wt / wt of at least one polymeric binder, wherein the thermoplastic compound has a melt flow index (MFI), as measured at 190°C and 2.16 Kg, ranging between about 0.01 to about 10 g / 10 min.

2. The thermoplastic compound according to claim 1, wherein the recycled or post-production PEX is shredded, granulated, pulverized, or any combination thereof.

3. The thermoplastic compound according to claim 1 or claim 2, wherein at least one of the polymeric binders comprises a polyolefin.

4. The thermoplastic compound according to claim 3, wherein the polyolefin is selected from the group consisting of: polyethylene, polypropylene homopolymer, polypropylene copolymer, polybutadiene, polyisobutylene, polymethylpentene, cyclo-olefin copolymer, and any combination thereof.

5. The thermoplastic compound according to claim 4, wherein the polyethylene is high density polyethylene.

6. The thermoplastic compound according to any one of claims 1 -5, further comprising between about 0.1 %wt / wt to about 2 %wt / wt of at least one antioxidant.

7. The thermoplastic compound according to claim 6, wherein the at least one antioxidant is a sterically hindered phenolic compound, an aromatic phosphite compound, or any combination thereof.

8. The thermoplastic compound according to claim 7, wherein the sterically hindered phenolic compound is selected from the group consisting of butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tertiary-butylhydroquinone (TBHQ), 3,4,5-trihydroxybenzoic acid, catechin, epicatechin, quercetin, kaempferol, gallic acid, caffeic acid, coumaric acid, coumarine, and any combination thereof.

9. The thermoplastic compound according to claim 7, wherein the aromatic phosphite compound is selected from the group consisting of tetrakis(2,4-di-tert-butyl- phenyl)[l,l-biphenyl]-4,4’-diylbisphosphonite, bis(2,6-di-ter-butyl-4-methyl-phenyl)pentaerythritol- diphosphite, tri-(nonyl-phenyl) phosphite, tris(2,4-ditert-butylphenyl) phosphite, bis(2,4-di-t- butylphenyl)pentaerythritol diphosphite, tetraphenyl dipropylene glycol diphosphate, and any combination thereof.

10. The thermoplastic compound according to any one of claims 1-9, wherein the thermoplastic compound is in a form of powder, particles, pellets, or any combination thereof.

11. The thermoplastic compound according to claim 10, wherein the average diameter of the powder ranges between about 150 pm to about 500 pm, the average diameter of the particle ranging between about 3 mm to about 14 mm, and the longest dimension of the pellets ranging between about 3 to about 6 mm.

12. The thermoplastic compound according to any one of claims 1-11, wherein the thermoplastic compound has a melt flow index (MFI), as measured at 190 °C and 2.16 Kg, ranging between about 0.01 g / lOmin to about 4 g / lOmin.

13. The thermoplastic compound according to any one of claims 1-12, wherein the ratio of recycled or post-production PEX to binder ranges between about 4: 1 to about 1 : 1.

14. The thermoplastic compound according to any one of claims 1-13, wherein the recycled or post-production PEX is chemically cross-linked polyethylene, thermally cross-linked polyethylene, irradiation cross-linked polyethylene, or any combination thereof.

15. The thermoplastic compound according to any one of claims 1-14, wherein the recycled or post-processed PEX is derived from recycled PEX pipes or fittings, post-processed PEX material, PEX cable insulation, PEX foam, or any combination thereof.

16. A method for the preparation of a thermoplastic compound, the method comprising: shredding, granulating and / or pulverizing recycled or post-production cross-linked polyethylene (PEX) to achieve PEX powder; mixing about 50 %wt / wt to about 85 %wt / wt of the PEX powder with about 15 %wt / wt to about 50 %wt / wt of at least one polymeric binder to obtain a thermoplastic compound, wherein the thermoplastic compound has a melt flow index (MFI), as measured at 190 °C and 2.16 Kg, ranging between about 0.01 to about 10 g / lOmin.

17. The method according to claim 16, wherein the recycled PEX is obtained from shredding, granulation and / or pulverizing PEX pipes and fittings, post-processed PEX material, PEX cable insulation, PEX foam, or any combination thereof.

18. The method according to claim 16, wherein the recycled PEX is from recycling chemically cross-linked polyethylene, thermally cross-linked polyethylene, irradiation cross-linked polyethylene, or any combination thereof.

19. The method according to any one of claims 16-18, wherein the shredding, granulation and pulverizing is carried out in a rotary blades type shredder, high speed rotating blades cylinder type granulator, rotary discs pulverizer, twin-roll cracker, refiner mill, or any combination thereof.

20. The method according to claim 19, wherein the shredding, granulation and pulverizing is carried out at room temperature or when cooled to -80°C or below by means of a cryogenic system.

21. The method according to claim 16, wherein the mixing is carried out in a co-rotating twin- screw type compounding extruder or single screw extruder recycling unit.

22. The method according to any one of claims 16-21, further comprising adding at least one antioxidant.

23. The method according to claim 22, wherein the at least one antioxidant is a sterically hindered phenolic compound, an aromatic phosphite compound, or any combination thereof.

24. The method according to claim 23, wherein the sterically hindered phenolic compound is selected from the group consisting of butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tertiary-butylhydroquinone (TBHQ), 3,4,5-trihydroxybenzoic acid, catechin, epicatechin, quercetin, kaempferol, gallic acid, caffeic acid, coumaric acid, coumarine, and any combination thereof.

25. The method according to claim 23, wherein the aromatic phosphite compound is selected from the group consisting of tetrakis(2,4-di -tert-butyl- phenyl)[l,l-biphenyl]-4,4’- diylbisphosphonite, bis(2,6-di-ter-butyl-4-methyl- phenyl)pentaerythritol-diphosphite, tri- (nonyl-phenyl) phosphite, tris(2,4-ditert-butylphenyl) phosphite, bis(2,4-di-t- butylphenyl)pentaerythritol diphosphate, tetraphenyl dipropylene glycol diphosphate, and any combination thereof.

26. The method according to any one of claims 16-25, wherein the ratio of recycled PEX powder to binder ranges between about 4: 1 to about 1 :1.

27. A method of producing a recycled or post-production PEX- based article of manufacture, the method comprising:heating the thermoplastic compound of any one of claims 1-15 or the thermoplastic compound produced by the method of any one of claims 16-26 with a thermoplastic polymeric mixture to form a melt, wherein a ratio of recycled or post-production crosslinked polyethylene (PEX) powder to total compound matrix in the melt ranges from about 1 :20 to about 1 : 1.5; and extruding, injecting, or compression molding the melt under predetermined pressure and temperature conditions, to produce an article of manufacture from the thermoplastic compound having a wall or section thereof with a thickness of at least about 2 mm.

28. The method according to claim 27, wherein the additional thermoplastic polymeric mixture comprises one or more polyolefins selected from the group consisting of: polyethylene, polypropylene homopolymer, polypropylene copolymer, polybutadiene, polyisobutylene, polymethylpentene, cyclo-olefin copolymer or any combination thereof.

29. The method according to claim 27, wherein the predetermined pressure for injection ranges between about 600 to about 2,500 bar.

30. The method according to claim 27, wherein the predetermined temperature for injection ranges between about 190°C to about 280°C.

31. The method according to claim 27, wherein the predetermined pressure for extrusion ranges between about 70 to about 150 bar.

32. The method according to claim 27, wherein the predetermined temperature for extrusion ranges between about 200°C to about 250°C.

33. The method according to claim 27, wherein the predetermined pressure for compression molding ranges between about 14 to about 245 bar.

34. The method according to claim 27, wherein the predetermined temperature for compression molding ranges between about 190°C to about 280°C.

35. The method according to any one of claims 27-34, wherein the predetermined temperature for extrusion, injection or compression molding is the temperature of the barrel.

36. The method according to any one of claims 27-35, wherein the PEX-based article of manufacture has a wall or section thereof with a thickness ranging between about 2 mm to about 25 cm.

37. The method according to any one of claims 27-36, further comprising foaming the melt prior to extrusion, injection, or compression molding.

38. The method according to claim 37, further comprising adding a foaming agent to the melt.

39. The method according to claim 38, wherein the foaming agent is selected from the group consisting of sodium bicarbonate, sodium carbonate, potassium bicarbonate and any combination thereof.

40. The method according to any one of claims 27-39, further comprising adding at least one antioxidant to the melt prior to extrusion, injection, or compression molding.

41. The method according to claim 40, wherein at least one antioxidant is a sterically hindered phenolic compound, an aromatic phosphite compound, or any combination thereof.

42. The method according to claim 41, wherein the sterically hindered phenolic compound is selected from the group consisting of butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tertiary-butylhydroquinone (TBHQ), 3,4,5-trihydroxybenzoic acid, catechin, epicatechin, quercetin, kaempferol, gallic acid, caffeic acid, coumaric acid, coumarine, and any combination thereof.

43. The method according to claim 41, wherein the aromatic phosphite compound is selected from the group consisting of tetrakis(2, 4-di -tert-butyl -phenyl)[ 1,1 -biphenyl]-4, 4’- diylbisphosphonite, bis(2,6-di-ter-butyl-4-methyl- phenyljpentaerythritol-diphosphite, tri- (nonyl-phenyl) phosphite, tris(2,4-ditert-butylphenyl) phosphite, bis(2,4-di-t- butylphenyljpentaerythritol diphosphate, tetraphenyl dipropylene glycol diphosphate, and any combination thereof.

44. The method according to any one of claims 27-43, for use in preparing water pipes, sewer trenches, habitats for domestic animals and fish, molds for construction (concrete), water tanks, box pallets, flat pallets, containers, trash bins, automotive parts, tiles, extruded profiles, toys, or any combination thereof.

45. An article of manufacture produced according to the method of any one of claims 27-44.

46. The thermoplastic compound of any one of claims 1-15 or the thermoplastic compound produced by the method of any one of claims 16-44, for use in producing an article of manufacture.

47. A method of producing a recycled or post-production PEX-based article of manufacture, the method comprising:about 50 %wt / wt to about 85 %wt / wt shredding, granulating and / or pulverizing recycled or post-production cross-linked polyethylene (PEX) to achieve PEX powder; adding about 15 %wt / wt to about 50 %wt / wt of at least one polymeric binder to the PEX powder to form a mixture of PEX and polymeric binder; and extruding, inj ecting, or compression molding the mixture under predetermined pressure and temperature conditions, to produce an article of manufacture from the thermoplastic compound having a wall or section thereof with a thickness of at least about 2 mm.

48. The method according to claim 47, further comprising adding at least one antioxidant, at least one foaming agent or both to the PEX powder.

49. The method according to any one of claims 47-48, wherein the average diameter of thePEX powder ranges between about 66 pm to about 500 pm.

50. A recycled or post-production PEX- based article of manufacture comprising the thermoplastic compound of any one of claims 1-15.

Images