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EP-4735522-A1 - POLYMER RECYCLATE BLEND PRODUCT AND PROCESS

EP4735522A1EP 4735522 A1EP4735522 A1EP 4735522A1EP-4735522-A1

Abstract

Provided are polymer recyclate blends having improved processability and/or organoleptic properties. The compositions comprise a homogenous matrix of a mixture of a polymer recyclate blend and an additive. The additive comprises an organic phosphite antioxidant, a hindered phenol antioxidant, a hydrophobic synthetic zeolite, or a combination thereof. Also provided are methods for making such compositions.

Inventors

  • SCHMIDT, RICHARD, P.
  • BRANNON, Todd, C.

Assignees

  • Equistar Chemicals, LP

Dates

Publication Date
20260506
Application Date
20240624

Claims (20)

  1. 1. A composition comprising a homogenous matrix of a mixture of: a) a polymer recyclate blend; and b) an additive, comprising: i) an organic phosphite antioxidant; ii) a hindered phenol antioxidant; iii) a hydrophobic synthetic zeolite; or iv) a combination thereof; wherein the mixture is subjected to compounding conditions sufficient to produce the homogenous matrix of the polymer recyclate blend and the additive.
  2. 2. The composition of claim 1, wherein the polymer recyclate blend comprises: a) a polymer recyclate in an amount in the range of from 5 wt. % to 65 wt. %; and b) a virgin HDPE component in an amount in the range of from 35 wt. % to 95 wt. %; wherein wt. % is based on the total weight of the polymer recyclate and the virgin HDPE component.
  3. 3. The composition of claim 1, wherein the polymer recyclate blend comprises: a) a polymer recyclate in an amount in the range of from 10 wt. % to 55 wt. %; and b) a virgin HDPE component in an amount in the range of from 45 wt. % to 90 wt. %; wherein wt. % is based on the total weight of the polymer recyclate and the virgin HDPE component.
  4. 4. The composition of claim 3, wherein: a) the polymer recyclate comprises a first HDPE in an amount greater than or equal to 80 wt. %, based on the weight of the polymer recyclate; b) the virgin HDPE component comprises a second HDPE in an amount greater than or equal to 80 wt. %, based on the weight of the virgin HDPE component; and c) the first HDPE and the second HDPE are the same or different.
  5. 5. The composition of claim 4, wherein the first HDPE and/or the second HDPE are homopolymers.
  6. 6. The composition of claim 1, wherein: a) the organic phosphite antioxidant is present in the mixture in an amount in the range of from 1 ppmw to 100 ppmw; b) the hindered phenol antioxidant is present in the mixture in an amount in the range of from 10 ppmw to 5000 ppmw; c) the hydrophobic synthetic zeolite is present in the mixture in an amount in the range of from 0. 1 wt. % to 6.0 wt. %; or d) a combination thereof; wherein ppmw and wt. % are based on the total weight of the polymer recyclate and the virgin HDPE component.
  7. 7. The composition of claim 1, wherein: a) the organic phosphite antioxidant is present in the mixture in an amount in the range of from 5 ppmw to 75 ppmw; b) the hindered phenol antioxidant is present in the mixture in an amount in the range of from 25 ppmw to 4000 ppmw; c) the hydrophobic synthetic zeolite is present in the mixture in an amount in the range of from 0.2 wt. % to 5.0 wt. %; or d) a combination thereof; wherein ppmw and wt. % are based on the total weight of the polymer recyclate and the virgin HDPE component.
  8. 8. The composition of claim 1, wherein the composition, when compared to the same composition excluding the additive, exhibits one or more of: a) a reduced diameter swell (Ud) and/or w eight swell (Uw), as measure by the Uniloy™ 5630 Dairy Mold Processability and Swell Test; b) a reduced gel content, as measured by the Optical Controls System (OCS) Gel Count; c) a reduction in volatile organic compounds (VOC) content from non-intentional added substances (NIAS), as measured by gas chromatography -mass spectrometry (GC-MS); and d) a reduction in yellowness, as measured by Color Index Testing (CIT, L*a*b*).
  9. 9. The composition of claim 8, wherein: a) the additive is a combination of the hindered phenol antioxidant and the organic phosphite antioxidant; and b) the composition exhibits a reduction in yellowness.
  10. 10. The composition of claim 8, wherein: a) the additive is the hydrophobic synthetic zeolite; and b) the composition exhibits a reduction in VOC content.
  11. 11. The composition of claim 8, wherein: a) the additive is a combination of the hindered phenol antioxidant, the organic phosphite antioxidant, and the hydrophobic synthetic zeolite; and b) the composition exhibits a reduction in yellowness and a reduction in VOC content.
  12. 12. The composition of claim 1, wherein the compounding conditions are implemented in a compounding zone of an extruder or mixer and include one or more of temperature, pressure, and shear force.
  13. 13. The composition of claim 1, wherein the compounding conditions comprise a temperature in the range of from 125°C to 300°C.
  14. 14. The composition of claim 1 , wherein: a) the organic phosphite antioxidant comprises di(2,4-di-tert- butylphenyl)pentaerithritol diphosphite; b) the hindered phenol antioxidant comprises 2,5,7,8-tetramethyl-2-(4,8,12- trimethyltridecyl)chroman-6-ol ; and c) the hydrophobic synthetic zeolite comprises a 30% Zeolite silica-rich, powder identified by CAS# 1318-02-1.
  15. 15. A method for improving the processability and/or organoleptic properties of a first polymer recyclate blend, the method comprising: a) forming a mixture of the first polymer recyclate blend with an additive, wherein the additive comprises: i) an organic phosphite antioxidant; ii) a hindered phenol antioxidant; iii) a hydrophobic synthetic zeolite; or iv) a combination thereof; and b) subjecting the mixture to compounding conditions sufficient to form a second recyclate polymer blend, wherein the second recyclate polymer blend is a homogenous matrix of the first recyclate polymer blend and the additive.
  16. 16. The method of claim 15, wherein the first recyclate polymer blend comprises: a) a polymer recyclate in an amount in the range of from 5 wt. % to 65 wt. %; and b) a virgin HDPE component in an amount in the range of from 35 wt. % to 95 wt. %; wherein wt. % is based on the total weight of the polymer recyclate and the virgin HDPE component.
  17. 17. The method of claim 15, wherein the mixture comprises: a) the organic phosphite antioxidant is present in an amount in the range of from 1 ppmw to 100 ppmw; b) the hindered phenol antioxidant is present in an amount in the range of from 10 ppmw to 5000 ppmw; c) the hydrophobic synthetic zeolite is present in an amount in the range of from 0. 1 wt. % to 6.0 wt. %; or d) a combination thereof; wherein ppmw and wt. % are based on the total weight of the polymer recyclate and the virgin HDPE component.
  18. 18. The method of claim 15, wherein the second polymer recyclate blend, when compared to the first polymer recyclate blend, exhibits one or more of: a) a reduced diameter swell (Ud) and/or weight swell (Uw), as measure by the Uniloy™ 5630 Dairy Mold Processability and Swell Test; b) a reduced gel content, as measured by the Optical Controls System (OCS) Gel Count; c) a reduction in volatile organic compounds (VOC) content from non-intentional added substances (NIAS), as measured by gas chromatography -mass spectrometry 7 (GC-MS); and d) a reduction in yellowness, as measured by Color Index Testing (CIT, L*a*b*).
  19. 19. The method of claim 15, wherein the compounding conditions are implemented in a compounding zone of an extruder or mixer and include one or more of temperature, pressure, and shear force.
  20. 20. The method of claim 15, wherein the compounding conditions comprise a temperature in the range of from 125°C to 300°C.

Description

POLYMER RECYCLATE BLEND PRODUCT AND PROCESS PRIOR RELATED APPLICATIONS [0001] This application filed under the Patent Cooperation Treaty, which claims the benefit of priority to U.S. Provisional Application No. 63/523,574, filed on June 27, 2023, which is incorporated herein by reference in its entirety. FIELD OF THE INVENTION [0002] The present disclosure relates to polymer recyclate blends having improved processability and/or organoleptic properties and methods for producing such products. BACKGROUND OF THE INVENTION [0003] Polyolefins, in particular polyethylene, is increasingly consumed in large amounts for many applications, including packaging for food and other goods, electronics, automotive components, and a great variety of manufactured articles. Large amounts of waste plastic materials are presently coming from differential recovery of municipal plastic wastes, mainly constituted of flexible packaging (cast film, blown film and BOPP film), rigid packaging, blow molded bottles, and injection molded containers. Usually, recovery of polymer recyclate includes a step of separation of various types of polymers prior to further processing as post-consumer recycle (PCR) resins. [0004] Some PCR resin suppliers carry a U.S. Food and Drug Administration (FDA) Noobjection Letter (NOL) for food contact applications, including liquid food applications such as dairy, water, and juice packaging. Some such PCRs are advertised as recycled resin primarily comprising recycled homopolymer HDPE containers, such as gallon milk containers. However, testing of some of these PCRs via GC-MS, NMR, FTIR, and Liquid Chromatography Additives (LC ADDS) indicate the presence of trace amounts of cellulose, oxidized polymer, and other non- intentional added substances (NIAS) in the PCR resins. [0005] When containers are molded from polymer blends comprising a portion of these PCRs, the trace amounts of these contaminates can potentially introduce unintended odors and/or flavors into liquid food contents stored in such container. Additionally, when compared to containers produced with all virgin polymers, the presence of these contaminants may result in molded containers having unfavorable aesthetics due to unintended yellowing and/or gel formation in the resin occurring during the molding process. [0006] There is a need to provide processes for improved recycling of such PCR resins and to produce compositions comprising such recycled materials having a useful combination of properties that are equal to or better than analogous virgin compositions. Ideally, such processes would be highly flexible and could be implemented with commonly used equipment and familiar techniques to produce a wide variety of products. SUMMARY OF THE INVENTION [0007] The present disclosure relates to a composition comprising a homogenous matrix of a mixture of a polymer recyclate blend and an additive. The additive comprises an organic phosphite antioxidant, a hindered phenol antioxidant, a hydrophobic synthetic zeolite, or a combination thereof. The mixture is subjected to compounding conditions sufficient to produce the homogenous matrix of the polymer recyclate blend and the additive, wherein the composition has improved processability and/or organoleptic properties when compared to the polymer recyclate blend alone. [0008] In some embodiments, the polymer recyclate blend comprises a polymer recyclate in an amount in the range of from 5 wt. % to 65 wt. % and a virgin HDPE component is present in an amount in the range of from 35 wt. % to 95 wt. %, wherein wt. % is based on the total weight of the polymer recyclate and the virgin HDPE component. [0009] The disclosure further relates to a method for improving the processability and/or organoleptic properties of a first polymer recyclate blend. The method comprises forming a mixture of the first polymer recyclate blend with an additive. The additive comprises an organic phosphite antioxidant, a hindered phenol antioxidant, a hydrophobic synthetic zeolite, or combination thereof. The method further comprises subjecting the mixture to compounding conditions sufficient to form a second recyclate polymer blend, wherein the second recyclate polymer blend is a homogenous matrix of the first recyclate polymer blend and the additive. [0010] The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter, which form the subject matter of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiments disclosed may be readily utilized as a basis for modifying or designing other molded structures and/or processes for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such e