Polymeric resin compositions and articles manufactured therefrom

Abstract

A method of making a pelletized polymeric resin includes blending a first polymer component with a second polymer component to form a polymeric resin. The first polymer component is a high density polyethylene (HDPE) copolymer post-consumer resin (PCR). The second polymer component is a HDPE copolymer base resin. The method further includes extruding the polymeric resin to form polymeric resin extrudate, and pelletizing the polymeric resin extrudate to form a pelletized polymeric resin. In some embodiments, a method of making pelletized polymeric resin includes blending a first polymer component with a second polymer component to form a polymeric resin. The polymeric resin includes a density greater than about 0.94 g / cm3 and a melt index of less than about 0.4 g / 10 min. The method further includes extruding the polymeric resin to form polymeric resin extrudate, and pelletizing the polymeric resin extrudate to form a pelletized polymeric resin.

Description

POLYMERIC RESIN COMPOSITIONS AND ARTICLES MANUFACTURED THEREFROMFIELD OF THE INVENTION

[0001] The present disclosure relates to polymeric resin compositions and articles manufactured therefrom.BACKGROUND OF THE INVENTION

[0002] Recycling and incorporating post-consumer waste products into materials used in manufacturing consumer products and resins has well been established in recent years. However, some manufacturing materials and products should meet stringent requirements to be deemed appropriate for certain applications. For example, materials used in conduit pipe applications should meet industry standards outlined in ASTM F2160, UL651A. and NEMA TC-7.

[0003] Unfortunately, such standards limit the level to which post-consumer waste products and post-consumer resins (PCR) can be incorporated into products and resins. In the example of conduit pipe applications, best-in-class slow crack growth resistance (ESCR) resins can only accommodate approximately 40 wt% high density polyethylene (HDPE) homopolymer PCR before the reduction in ESCR and tensile properties fall outside their predetermined minimum / maximum windows.

[0004] Thus, there is a need to develop new7polymeric resins with the abil i ty to accommodate increased levels of PCR while simultaneously maintaining material properties that satisfy the industry standards and requirements outlined in ASTM F2160, UL651A, and NEMA TC-7.SUMMARY OF THE INVENTION

[0005] The present disclosure relates to polymeric resin compositions and articles manufactured therefrom.

[0006] In some embodiments, a method of making a pelletized polymeric resin comprises blending a first polymer component with a second polymer component to form a polymeric resin. The first polymer component is a high density polyethylene (HDPE) copolymer post-consumer resin (PCR) comprising greater than 50 wt % of the polymeric resin. The second polymer component is a HDPE copolymer base resin. The method further comprises extruding the polymeric resin to form polymenc resin extrudate. The method further comprises pelletizing the polymeric resin extrudate to form a pelletized polymeric resin.

[0007] In some embodiments, a method of making pelletized polymeric resin comprises blending a first polymer component with a second polymer component to form a polymeric resin. The polymeric resin comprises a density greater than about 0.94 g / cm3and a melt index of less than about 0.4 g / 10 min, a flexural modulus of about 80,000 psi to 180,000 psi, a tensile strength at yield of about 3,000 psi to about 5,000 psi, and an environmental crack growth resistance greaterthan about 96 hrs based on a calculated specimen failure percentage of 10% (Fio). The method further comprises extruding the polymeric resin to form polymeric resin extrudate. The method further comprises pelletizing the polymeric resin extrudate to form a pelletized polymeric resin.DETAILED DESCRIPTION OF THE INVENTION

[0008] Resins of the current disclosure include one or more polymeric components, where at least one component includes a polymer having at least one ethylene monomeric unit. Notably, polymeric components of the present disclosure include copolymer compositions, namely polymers derived from two or more structurally distinct monomers. In one or more embodiments, at least one of the polymeric components includes a post-consumer resin (PCR). As used herein, “post-consumer resin” refers to a recycled polymeric material that has been processed (e.g., cut, shredded, or dismantled), and melt processed into a shape or mold (e g., pellets) suitable for use in product manufacturing. In some embodiments, a resin is a polymeric resin having a blend of tw o or more polymer components. For example, resins of the present disclosure can include a polymeric resin having two or more polymeric components, where the two or more polymeric components independently have a copolymer composition and at least one of the polymeric components is a PCR. In some embodiments, the PCR is not an HDPE homopolymer. In some embodiments, the polymeric resin is substantially or completely free of an HDPE homopolymer. Polymeric resins of the present disclosure can integrate higher levels of PCR than homopolymer resins having PCR, and without expressing the deleterious effects commonly associated therewith (e.g, reduction in material properties and processability). Without being bound by theory, it has been determined that the increased miscibility of the two or more polymeric components, as a result of their respective copolymer compositions, allows for higher levels of PCR incorporation into the polymeric resin without sacrificing material properties and ease of processing.

[0009] In at least one embodiment, a polymeric resin includes a blend of a first polymeric component and a second polymeric component, wherein the first polymeric component is a PCR, such as a high density polyethylene (HDPE) copolymer PCR. In some embodiments, the second polymeric component includes a HDPE copolymer base resin, such as a HDPE copolymer base resin commonly utilized as conduit pipe materials, which is not a PCR. In some embodiments, the polymeric resin is suitable for use in conduit pipe applications. Such materials and products produced from the polymeric resin satisfy one or more requirements outlined in ASTM F2160, UL651A. and / or NEMA TC-7, such as having a density greater than 0.94 g / cm3, having a melt index of less than 0.4 g / 10 min, having a flexural modulus ranging from 80,000 psi to 110,000 psi, having a tensile strength at yield ranging from 3000 psi to 3500 psi, and / or having an environmental crack growth resistance greater than 96 hrs based on a calculated specimen failure percentage of 10% (Fio).HDPE copolymer PCR

[0010] In some embodiments, the first polymeric components is a HDPE copolymer PCR having a density (as determined by ASTM1505) of about 0.940 g / cm3to about 0.975 g / cm3, such as about 0.940 g / cm3to about 0.960 g / cm3, such as about 0.940 g / cm3to about 0.955 g / cm3. In at least one embodiment, the HDPE copoly mer PCR has a melt index (as determined by ASTM D-1238, 190°C with a 2.16 kg load) of about 0.01 g / 10 min to about 20 g / 10 min, such as about 0.1 g / 10 min to about 10 g / 10 min, such as about 0.1 g / 10 min to about 5 g / 10 min such as about 0.1 g / 10 min to about 0.5 g / 10 min.

[0011] In some embodiments, the HDPE copolymer PCR includes any one or more comonomers selected from propylene, 1-butene, 1-hexene, 1-octene, 4-methy 1-1 -pentene, and any combination thereof. In some embodiments, the HDPE copolymer PCR includes about 0. 1 mol % to about 99.9 mol % of ethylene repeat units, such as about 91 mol % to about 99 mol %, such as about 92 mol % to about 98 mol %, such as about 93 mol % to about 97 mol %, such as about 94 mol % to about 96 mol %. In at least one embodiment, the HDPE copolymer PCR is sourced from post-consumer waste products, such as products formed from HDPE copolymer resins typically used for small blow molding applications.

[0012] In some embodiments, the HDPE copolymer PCR has a backbone architecture of at least one of a random copolymer, a block copolymer, an alternating copolymer, or a gradient copolymer. In one or more embodiments, the HDPE copolymer PCR is a random copolymer. In one or more embodiments, the HDPE copolymer PCR includes a molar ratio of ethylene repeat units to any one or more comonomer repeat units of about 4: 1 to about 99.9:0.1 .

[0013] In some embodiments, the HDPE copolymer PCR includes a weight average molecular weight (Mw), as determined by gel permeation chromatography (GPC), of about 40,000 g / mol to about 500,000 g / mol, such as about 80,000 g / mol to about 350,000 g / mol, such as about 100,000 g / mol to about 200,000 g / mol.HDPE copolymer base resin

[0014] In some embodiments, the second polymeric component is a HDPE copolymer base resin having a density (as determined by ASTM D-1505) of about 0.940 g / cm3to about 0.960 g / cm3, such as about 0.945 g / cm3to about 0.955 g / cm3, such as about 0.948 g / cm3to about 0.952 g / cm3. In at least one embodiment, the HDPE copolymer base resin has a melt index (as determined by ASTM D-1238, 190°C with a 2. 16 kg load) of about 0.01 g / 10 min to about 20 g / 10 min, such as about 0. 1 g / 10 min to about 10 g / 10 min, such as about 0. 1 g / 10 min to about 5 g / 10 min such as about 0.1 g / 10 min to about 0.5 g / 10 min.

[0015] In some embodiments, the HDPE copolymer base resin includes any one or more comonomers selected from propylene, 1 -butene, 1 -hexene, 1 -octene, 4-methyl-l -pentene, and any combination thereof. In some embodiments, the HDPE copolymer base resin includes about 0. 1 mol % to about 99.9 mol % of ethylene repeat units, such as about 91 mol % to about 99 mol %, such as about 92 mol % to about 98 mol %. such as about 93 mol % to about 97 mol %, such as about 94 mol % to about 96 mol %.

[0016] In some embodiments, the HDPE copolymer base resin includes a backbone architecture of at least one of a random copolymer, a block copolymer, an alternating copolymer, or a gradient copolymer. In one or more embodiments, the HDPE copolymer base resin is a random copolymer. In one or more embodiments, the HDPE copolymer base resin includes a molar ratio of ethylene repeat units to any one or more comonomer repeat units of about 4: 1 to about 99.9:0. 1.

[0017] In some embodiments, the HDPE copolymer base resin includes a Mw, as determined by GPC, of about 40,000 g / mol to about 500,000 g / mol, such as about 80,000 g / mol to about 350,000 g / mol, such as about 100,000 g / mol to about 200,000 g / mol.Polymeric Resin and Components Thereof

[0018] In one or more embodiments, the polymeric resin includes about 1 wt% to about 99 wt% of HDPE copolymer PCR, such as about 10 wt% to about 90 wt%, such as about 20 wt% to about 80 wt%, such as about 30 wt% to about 70 wt%, such as about 40 wt% to about 60 wt%, such as about 45 wt% to about 55 wt%. In at least one embodiment, HDPE copolymer PCR includes at least 50 wt% of the polymeric resin. In one or more alternative embodiments, the polymeric resin includes about 50 wt% to about 99 wt% of HDPE copolymer PCR, alternatively about 50 wt% to about 75 wt%.

[0019] In one or more embodiments, the polymeric resin includes about 1 wt% to about 99 wt% of HDPE copolymer base resin, such as about 10 wt% to about 90 wt%, such as about 20 wt% to about 80 wt%, such as about 30 wt% to about 70 wt%, such as about 40 wt% to about 60 wt%, such as about 45 wt% to about 55 wt%. In at least one embodiment, HDPE copolymer base resin includes less than 50 wt% of the polymeric resin. In one or more alternative embodiments, the polymeric resin includes about 50 wt% to about 99 wt% of HDPE copolymer base resin, alternatively about 50 wt% to about 75 wt%, alternatively about 1 wt% to about 50 wt%. Without being bound by theory , the copoly mer compositions of both the HDPE copolymer PCR and the HDPE copolymer base resin increase the compatibility and miscibility of the two components. Thus, the resulting polymeric resin includes higher amounts of recycled post-consumer resin material.

[0020] In some embodiments, the polymeric resin can further include any one or more additives. Suitable additives include, but are not limited to UV stabilizers, flame retardants, fillers, andpigments. Additives are important in establishing the long term stability of the polymeric resin as well as the resulting material’s chemical and impact resistance.

[0021] In one or more embodiments, the polymeric resin further includes one or more UV stabilizers in an amount of about 1500 ppm to about 2500 ppm, such as about 1750 ppm to about 2250 ppm, such as about 2000 ppm. Suitable UV stabilizers include, but are not limited to, hindered amine light stabilizers ("HALS"). Examples of HALS include: Chimassorb 944, Chimassorb 994, Chimassorb 905, Tinuvin 770, Tinuvin 992, Tinuvin 622, Tinuvin 144, and Spinuvex A36 available from Geigy; and Cyasorb UV 3346 and Cyasorb UV 944 commercially available American Cyanamide. Particularly preferred UV stabilizers are Cytec UV 3346 and Chimassorb 944 (poly[N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)-l,6-hexanediamine-co-2,4- dichl oro-6-morpholino- 1,3,5 -tri azine) .

[0022] In one or more embodiments, the polymeric resin further includes one or more flame retardants. Flame retardants include, for example, halogen-containing compounds, antimony oxides, or phosphorus compounds. Suitable flame retardants include, but are not limited to aluminum trihydrate, antimony oxide (SbaOs), and decabromobiphenyl oxide ("decabrome").

[0023] In some embodiments, the polymeric resin is prepared by blending a HDPE copolymer PCR feed, a HDPE copolymer base resin feed, and optionally any one or more additional polymers and additives via any suitable blending technique. The additional optional polymers can be, but are not limited to, low density polyethylene (LDPE), medium density polyethylene (MDPE), polypropylene, polyester, acrylic resin, polyvinyl alcohol, polyvinyl chloride, polyvinyl acetate, polyvinyl ether, ethylene-vinyl acetate copolymers (EVA), ethylenevinyl alcohol copolymers (EV OH), ethylene-acrylic acid copolymers, and the like, and mixtures thereof. In at least one embodiment, the optional polymer includes less than 10 wt% of the polymeric resin.

[0024] The first polymeric component, second polymeric component, and optional additives can be blended in solution or in thermal processing. In some embodiments, melt screw extrusion is implemented to form the polymeric resin extrudate, which can then be further processed via pelletization to form a pelletized polymeric resin. Melt blending is one suitable method for preparing the final polymer blend of the present disclosure, although any suitable polymer blending techniques available to those of ordinary skill in the art may be used. Techniques for melt blending of a polymer with additives of all types are known to those of ordinary skill the art and can typically be used with the present disclosure. In one type of melt blending operation useful with the present disclosure, the individual components of the blend are combined in a mechanical extruder or mixer, and then heated to a temperature sufficient to form a polymer melt.

[0025] The mechanical mixer can be a continuous or batch mixer. Examples of suitable continuous mixers include single screw extruders, intermeshing co-rotating twin screw extruderssuch as Wemer & Pfleiderer ZSK™ extruders, counter-rotating twin screw extruders such as those manufactured by Leistritz™, and reciprocating single screw kneaders such as Buss™ co-kneaders. Examples of suitable batch mixers are lateral 2-roll mixers such as Banbury™ or Boling™ mixers. The temperature of the melt, residence time of the melt within the mixer, and the mechanical design of the mixer are several well-known variables that control the amount of shear to be applied to the composition during mixing, and can be readily selected by one of ordinary skill in the art based on the disclosure of the disclosure herein.

[0026] The polymeric resin disclosed herein may be pelletized via strand pelleting or commercial underwater pelletization. Pellets of the polymeric resin may then be easily processed into shaped articles by injection molding, profile extrusion, blow molding, and other forming processes to give products which have well balanced properties suitable for commercial applications.

[0027] In at least one embodiment, pellets of the polymeric resin are formed in a continuous process. As such, components of the polymeric resin are fed into a continuous mixer, a single screw or twin screw extruder via volumetric or gravimetric feeders. The extruder is heated to a temperature sufficient to melt the polymers, for example between 150 °C and 500 °C. The components are fed into an extruder and mixed / blended together in a molten state. The extruder speed may be from about 1 to about 1000 revolutions per minute (rpm), more typically from about 10 to about 500 rpm. The gas from the extruder may be evacuated by a vacuum pump. The polymeric resin extrudate is typically cooled (e.g., in a water bath or underwater pelletizer) and pelletized to form pellets of the polymeric resin.

[0028] In at least one embodiment, pellets of the polymeric resin are formed in a batch process. As such, components of the polymeric resin are added to a mixing device, such as a Banbury’ mixer, and heated to a temperature sufficient to melt the polymer, such as about 150 °C to about 400 °C. The mixing speed is typically about 1 to about 100 rpm. The output from the mixer was cooled and pelletized to form pellets of the polymeric resin.

[0029] In one or more embodiments, the polymeric resin, or pellets thereof, is useful for making articles by injection molding, blow molding, rotomolding. and compression molding. The resin is also useful for making films, extrusion coatings, pipes, sheets, and fibers. Products that can be made from the resin include grocery bags, trash bags, merchandise bags, pails, crates, detergent bottles, toys, coolers, corrugated pipe, housewrap, shipping envelopes, protective packaging, wire & cable applications, and many others.

[0030] In some embodiments, the polymeric resin is suitable for producing pipes or piping components. In general, materials and products produced using the polymeric resin exhibit environmental stress crack resistance and tensile properties required for use in conduit pipe applications, as outlined in ASTM F2160, UL651A, and NEMA TC-7 (incorporated herein byreference). ASTM F2160 is the primary standard to meet where the minimum cell classification as defined by ASTM D3350 is PE334480C or E, where material property thresholds pertaining to density, melt index, flexural modulus, tensile strength at yield, and crack growth resistance should be satisfied.

[0031] The density of the polymeric resin is determined in accordance with ASTM D-1505. In some embodiments, the polymeric resin has a density of about 0.940 g / cm3to about 0.975 g / cm3, such as about 0.940 g / cm3to about 0.965 g / cm3, such as about 0.940 g / cm3to about 0.950 g / cm3. In at least one embodiment, the polymeric resin has a density greater than 0.940 g / cm3.

[0032] The melt index of the polymeric resin is determined in accordance to ASTM D-1238. In some embodiments, the polymeric resin has a melt index of about 0.1 g / 10 min to about 0.4 g / 10 min, such as about 0.2 g / 10 min to about 0.4 g / 10 min, such as about 0.3 g / 10 min to about 0.4 g / 10 min. In at least one embodiment, the polymeric resin has a melt index less than 0.4 g / 10 min.

[0033] The environmental stress crack resistance (ESCR) of the polymeric resin is determined in accordance to ASTM DI 693, wherein the polymeric resin is molded into a plaque and die cut into a suitable specimen. In some embodiments, the average time to failure was about 100 hrs to about 1,000 hrs, such as about 100 hrs to about 500 hrs, such as about 100 hrs to about 250 hrs. In at least one embodiment, the average time to failure was greater than 96 hrs.

[0034] Environmental Stress Crack Resistance (ESCR Bell Telephone Test) is measured according to ASTM D1693:2021 (Method B). 10 rectangular test specimens (38 x 13 x 2 mm) are cut from a compression moulded sheet, which has been prepared according to ASTM D4703 requirements (average cooling rate 15 K / min and high pressure during cooling phase). The specimens are notched with a razor to a depth of 0.4 mm parallel to the longitudinal axes, centered on one of the broad faces. Afterward the specimens are bent in a U-shape with a special bending device, with the notched side pointing upwards. Within 10 minutes from bending, the U-shaped specimens are put into a glass tube and filled with a 10% vol. aqueous solution of 4-Nonylphenyl- poly ethylene glycol (Arkopal N100) at 50°C and sealed with a rubber stopper. The specimens are inspected visually for cracks every hour on the first day, then even’ day and after 7 days on a weekly basis (every 168 h). The final value obtained is the 10% failure point (F / 6) of the 10 test specimen in the glass tube.

[0035] The flexural modulus of the polymeric resin is determined in accordance to ASTM D790. In some embodiments, the polymeric resin has a flexural modulus of about 80,000 psi to about 180,000 psi, such as about 85,000 psi to about 160,000 psi, such as about 90,000 psi to about 150,000 psi.

[0036] The tensile strength at yield of the polymeric resin is determined in accordance to ASTM D-638. In some embodiments, the polymeric resin has a tensile strength at yield of about 3,000psi to about 5,000 psi, such as about 3,000 psi to about 4,000 psi. In some embodiments, the polymeric resin has a tensile strength at yield of greater than 3,500 psi.

[0037] The polymeric resin of the present disclosure further includes comparable processability to other commercially available resins, such as Alathon L4930TC as sourced from Equistar, Marlex 9332 as sourced from Chevron-Phillips Chemical, Marlex TRB-223 as sourced from Chevron- Phillips Chemical, TC46-25 as sourced from Ineos, and the like.

[0038] Overall, the polymer resin of the present disclosure includes high amounts of HDPE copolymer PCR while maintaining the minimum cell classification as defined by ASTM D3350 in PE334480C or PE334480E. Additionally, the polymer resin of the present disclosure exhibits comparable processability to various commercial resins.

[0039] The phrases, unless otherwise specified, "consists essentially of' and "consisting essentially of do not exclude the presence of other steps, elements, or materials, whether or not, specifically mentioned in this specification, so long as such steps, elements, or materials, do not affect the basic and novel characteristics of the present disclosure, additionally, they do not exclude impurities and variances normally associated with the elements and materials used.

[0040] For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, within a range includes every7point or individual value between its end points even though not explicitly recited. Thus, every7point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.

[0041] All documents described herein are incorporated by reference herein, including any priority documents and or testing procedures to the extent they are not inconsistent with this text. As is apparent from the foregoing general description and the specific embodiments, while forms of the present disclosure have been illustrated and described, various modifications can be made without departing from the spirit and scope of the present disclosure. Accordingly, it is not intended that the present disclosure be limited thereby. Likewise, the term “comprising” is considered synonymous with the term “including” for purposes of United States law. Likewise whenever a composition, an element or a group of elements is preceded with the transitional phrase “comprising,” it is understood that we also contemplate the same composition or group of elements with transitional phrases “consisting essentially of,” “consisting of,” “selected from the group ofconsisting of” or “is” preceding the recitation of the composition, element, or elements and vice versa.

[0042] While the present disclosure has been described with respect to a number of embodiments and examples, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope and spirit of the present disclosure.

Claims

CLAIMS1. A method of making a pelletized polymeric resin, comprising: blending a first polymer component with a second polymer component to form a polymeric resin, wherein: the first polymer component is a high density polyethylene (HDPE) copolymer post-consumer resin (PCR), the HDPE copolymer PCR comprising greater than 50 wt % of the polymeric resin, and the second polymer component is a high density polyethylene (HDPE) copolymer base resin; and extruding the polymeric resin to form polymeric resin extrudate; and pelletizing the polymeric resin extrudate to form a pelletized polymeric resin.

2. The method of claim 1, wherein the HDPE copolymer PCR comprises about 0. 1 mol % to about 99.9 mol % of ethylene units.

3. The method of claim 2, wherein the HDPE copolymer PCR comprises comonomer units selected from the group consisting of propylene, 1 -butene, 1 -hexene, 1 -octene, 4-methyl-l -pentene, and any combination thereof.

4. The method of claim 3, wherein the molar ratio of ethylene units to any one or more comonomer units of the HDPE copolymer PCR is about 4: 1 to about 99.9:0.1.

5. The method of claim 1, wherein the HDPE copolymer base resin comprises about 91 mol % to about 99 mol % of ethylene units.

6. The method of claim 2, wherein the HDPE copolymer base resin further comprises comonomer units selected from the group consisting of propylene, 1-butene, 1-hexene, 1-octene. 4-methyl-l- pentene, and any combination thereof.

7. The method of claim 3, wherein the molar ratio of ethylene units to any one or more comonomer units of the HDPE copolymer base resin is about 4: 1 to about 99.9:

0. 1.

8. The method of claim 1, wherein the HDPE copolymer PCR comprises about 50 wt % to about 99 wt % of the resin.

8. The method of claim 1, wherein the HDPE copolymer base resin comprises about 1 wt % to about 50 wt % of the resin.

9. The method of claim 1, wherein the polymeric resin further comprises one or more additional polymers and additives, the one or more additional polymers and additives comprising less than 10 wt % of the resin.

10. The method of claim 9, wherein the one or more additional polymers is selected from the group consisting of low density polyethylene (LDPE), medium density polyethylene (MDPE), polypropylene, polyester, acrylic resin, polyvinyl alcohol, polyvinyl chloride, polyvinyl acetate, polyvinyl ether, ethylene-vinyl acetate copolymers (EVA), ethylenevinyl alcohol copolymers (EV OH), ethylene-acry lic acid copolymers, and combinations thereof.

11. A method of making pelletized polymeric resin, comprising: blending a first polymer component with a second polymer component to form a polymeric resin, the polymeric resin having: a density' greater than about 0.94 g / cm3, a melt index of less than about 0.4 g / 10 min, a flexural modulus of about 80,000 psi to 180,000 psi, a tensile strength at yield of about 3,000 psi to about 5,000 psi, and an environmental crack growth resistance greater than about 96 hrs based on a calculated specimen failure percentage of 10% (Fio), extruding the polymeric resin to form polymeric resin extrudate; and pelletizing the polymeric resin extrudate to form a pelletized polymeric resin.

12. The method of claim 11, wherein the polymer resin comprises a first polymer component blended with a second polymer component, wherein: the first polymer component is a high density7polyethylene (HDPE) copolymer postconsumer resin (PCR), and the second polymer component is a high density polyethylene (HDPE) copolymer base resin.

13. The method of claim 12, wherein the HDPE copolymer PCR resin comprises about 0.1 mol % to about 99.9 mol % of ethylene units.

14. The method of claim 13, wherein the HDPE copolymer PCR further comprises comonomer units selected from the group consisting of propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-l- pentene, and any combination thereof.

15. The method of claim 14. wherein the molar ratio of ethylene units to any one or more comonomer units of the HDPE copolymer PCR is about 4: 1 to about 99.9:

0. 1.

16. The method of claim 12, wherein the HDPE copolymer base resin comprises about 91 mol % to about 99 mol % of ethylene units.

17. The method of claim 13, wherein the HDPE copolymer base resin further comprises a comonomer units selected from the group consisting of propylene, 1 -butene, 1 -hexene, 1 -octene, 4-methyl-l-pentene, and any combination thereof.

18. The method of claim 14, wherein the molar ratio of ethylene units to any one or more comonomer units of the HDPE copolymer resin is about 4: 1 to about 99.9:0.

19. The method of claim 12, wherein the HDPE copolymer PCR comprises about 50 wt % to about 99 wt % of the resin.

20. The method of claim 12, wherein the HDPE copolymer base resin comprises about 1 wt % to about 50 wt % of the resin.