Antioxidant blends for polymer stabilization

Abstract

Antioxidant blends comprising a phenolic antioxidant, a phosphite antioxidant, and a lactone-based antioxidant and for use in polymeric materials. The phenolic antioxidant may be configured to scavenge oxygen-centered free radicals in the polymeric materials. The phosphite antioxidant may be configured to scavenge unstable compounds, such as hydroperoxides, in the polymeric materials. The lactone-based antioxidant may be configured to scavenge carbon-centered free radicals in the polymeric materials. The antioxidant blends may be added to polymers to reduce the oxidation and degradation of the polymers to increase the service life of the polymers. Polymers comprising the antioxidant blends may have increased long-term durability and may be utilized at high temperatures and in humid conditions, such as pasteurization conditions.

Description

ANTIOXIDANT BLENDS FOR POLYMER STABILIZATIONBACKGROUND1. Field

[0001] Embodiments of the present disclosure generally relate to antioxidant blends. More specifically, embodiments of the present disclosure relate to antioxidant blends for scavenging free radicals formed by the degradation of polymers, such as polyolefins. 2. Related Art

[0002] Polymers may degrade due to high temperatures, shear, or reaction with entrapped oxygen or catalyst residues. As polymers degrade, free radicals are formed as carbon-centered free radicals and oxygen-centered free radicals that cause further degradation of the polymers. Techniques for reducing degradation in polymers utilize antioxidants to reduce the oxidation of polymers by scavenging the free radicals formed by the degradation of polymers. Typical antioxidants added to polymers are designed to scavenge oxygen-centered free radicals but not carbon-centered free radicals. Additionally, typical antioxidants are not stable at high temperatures and in humid conditions. For example, typical antioxidants migrate to the substrate surface and degrade by hydrolysis at high temperatures and humid conditions, thereby reducing the service life of the polymer. Current antioxidant blends lack the ability to scavenge oxygencentered free radicals and carbon-centered free radicals and to remain stable in high temperatures and humid conditions.Docket No. 2919-3.01 1SUMMARY

[0003] Embodiments of the present disclosure solve the above-mentioned problems by providing antioxidant blends for scavenging both oxygen-centered free radicals and carbon-centered free radicals. In particular, embodiments of the present disclosure include antioxidant blends comprising a phenolic antioxidant, a phosphite antioxidant, and a lactone-based antioxidant. The antioxidant blends described herein scavenge both carbon-centered free radicals and oxygen-centered free radicals to thereby reduce or prevent the oxidation and degradation of polymeric materials and increase the service life of the polymers. Further, embodiments of the present disclosure include antioxidants that remain stable and do not degrade at high temperatures and in humid conditions. Accordingly, the antioxidant blends described herein may be utilized at high temperatures and in humid conditions, such as in polymers subject to pasteurization conditions.

[0004] Clause 1. A material comprising: a base material; and an antioxidant blend, wherein the antioxidant blend comprises: a lactone-based antioxidant; a phenolic antioxidant; and a phosphite antioxidant.

[0005] Clause 2. The material of clause 1, wherein the base material comprises a polymer.

[0006] Clause 3. The material of any of clauses 1 or 2, wherein the antioxidant blend is dispersed throughout the base material.

[0007] Clause 4. The material of any of clauses 1 through 3, wherein the antioxidant blend is configured to reduce degradation of the base material.

[0008] Clause 5. The material of any of clauses 1 through 4, wherein the antioxidant blend is configured to reduce degradation of the polymer.Docket No. 2919-3.01 2

[0009] Clause 6. The material of any of clauses 1 through 5, wherein the lactone-based antioxidant reacts with carbon-centered free radicals in the base material.

[0010] Clause 7. The material of any of clauses 1 through 6, wherein the lactone-based antioxidant reacts with carbon-centered free radicals in the polymer.

[0011] Clause 8. The material of any of clauses 1 through 7, wherein the carboncentered free radicals are formed by a scission of the polymer caused by at least one of heat, shear, entrapped oxygen, and catalyst residue.

[0012] Clause 9. The material of any of clauses 1 through 8, wherein the phenolic antioxidant reacts with oxygen-centered free radicals in the base material.

[0013] Clause 10. The material of any of clauses 1 through 9, wherein the phenolic antioxidant reacts with oxygen-centered free radicals in the polymer.

[0014] Clause 11. The material of any of clauses 1 through 10, wherein the oxygencentered free radicals are formed by a first reaction of the polymer with the carboncentered free radicals and oxygen.

[0015] Clause 12. The material of any of clauses 1 through 11, wherein the phosphite antioxidant reacts with unstable compounds in the base material.

[0016] Clause 13. The material of any of clauses 1 through 12, wherein the phosphite antioxidant reacts with unstable compounds in the polymer.

[0017] Clause 14. The material of any of clauses 1 through 13, wherein the unstable compounds are formed by a second reaction of the polymer with the oxygen-centered free radicals.

[0018] Clause 15. The material of any of clauses 1 through 14, wherein the lactone-based antioxidant comprises a compound according to the formula:Docket No. 2919-3.01 3

[0019] Clause 16. The material of any of clauses 1 through 15, wherein R1, R2, and R3 are each independently chosen from a group consisting of a hydrocarbon, an alkyl, an aryl, an oligomer, and an additional polymer.

[0020] Clause 17. The material of any of clauses 1 through 16, wherein the lactone-based antioxidant comprises a compound according to the formula:

[0021] Clause 18. The material of any of clauses 1 through 17, wherein the phenolic antioxidant comprises a compound according to the formula:Docket No. 2919-3.01 4

[0022] Clause 19. The material of any of clauses 1 through 18, wherein the phosphite antioxidant comprises a compound according to the formula:

[0023] Clause 20. The material of any of clauses 1 through 19, wherein the phosphite antioxidant comprises a compound according to the formula:Docket No. 2919-3.01 5

[0024] Clause 21. The material of any of clauses 1 through 20, wherein the base material constitutes at least 90% of the material.

[0025] Clause 22. The material of any of clauses 1 through 21, wherein the antioxidant blend constitutes up to 7% of the material.

[0026] Clause 23. The material of any of clauses 1 through 22, wherein the phenolic antioxidant constitutes 40% to 65% of the antioxidant blend.

[0027] Clause 24. The material of any of clauses 1 through 23, wherein the phosphite antioxidant constitutes 25% to 50% of the antioxidant blend.

[0028] Clause 25. The material of any of clauses 1 through 24, wherein the lactone-based antioxidant constitutes up to 35% of the antioxidant blend.

[0029] Clause 26. The material of any of clauses 1 through 25, wherein the material is utilized in conditions having a temperature of up to 300°F.

[0030] Clause 27. The material of any of clauses 1 through 26, wherein the antioxidant blend constitutes 10% to 0.02% of the material.

[0031] Clause 28. The material of any of clauses 1 through 27, wherein the antioxidant blend constitutes 5% to 0.02% of the material.

[0032] Clause 29. The material of any of clauses 1 through 28, wherein the antioxidant blend constitutes 1% to 0.02% of the material.Docket No. 2919-3.01 6

[0033] Clause 30. The material of any of clauses 1 through 29, wherein the phenolic antioxidant constitutes 30% to 75% of the antioxidant blend.

[0034] Clause 31. The material of any of clauses 1 through 30, wherein the phenolic antioxidant constitutes 50% to 55% of the antioxidant blend.

[0035] Clause 32. The material of any of clauses 1 through 31, wherein the phenolic antioxidant constitutes 33.3% of the antioxidant blend.

[0036] Clause 33. The material of any of clauses 1 through 32, wherein the phosphite antioxidant constitutes 5% to 70% of the antioxidant blend.

[0037] Clause 34. The material of any of clauses 1 through 33, wherein the phosphite antioxidant constitutes 30% to 45% of the antioxidant blend.

[0038] Clause 35. The material of any of clauses 1 through 34, wherein the phosphite antioxidant constitutes 33.3% of the antioxidant blend.

[0039] Clause 36. The material of any of clauses 1 through 35, wherein the lactone-based antioxidant constitutes up to 25% of the antioxidant blend.

[0040] Clause 37. The material of any of clauses 1 through 36, wherein the lactone-based antioxidant constitutes up to 20% of the antioxidant blend.

[0041] Clause 38. The material of any of clauses 1 through 37, wherein the lactone-based antioxidant constitutes up to 15% of the antioxidant blend.

[0042] Clause 39. An antioxidant blend comprising: a lactone-based antioxidant; a phenolic antioxidant; and a phosphite antioxidant.

[0043] Clause 40. The antioxidant blend of clause 39, wherein the antioxidant blend is for use with a polymer material.Docket No. 2919-3.01 7

[0044] Clause 41. The antioxidant blend of any of clauses 39 or 40, wherein the lactone-based antioxidant reacts with carbon-centered free radicals.

[0045] Clause 42. The antioxidant blend of any of clauses 39 through 41, wherein the lactone-based antioxidant reacts with carbon-centered free radicals in the polymer material.

[0046] Clause 43. The antioxidant blend of any of clauses 39 through 42, wherein the carbon-centered free radicals are formed by a scission of the polymer material caused by at least one of heat, shear, entrapped oxygen, and catalyst residue.

[0047] Clause 44. The antioxidant blend of any of clauses 39 through 43, wherein the phenolic antioxidant reacts with oxygen-centered free radicals.

[0048] Clause 45. The antioxidant blend of any of clauses 39 through 44, wherein the phenolic antioxidant reacts with oxygen-centered free radicals in the polymer material.

[0049] Clause 46. The antioxidant blend of any of clauses 39 through 45, wherein the oxygen-centered free radicals are formed by a first reaction of the polymer material with the carbon-centered free radicals and oxygen.

[0050] Clause 47. The antioxidant blend of any of clauses 39 through 46, wherein the phosphite antioxidant reacts with unstable compounds.

[0051] Clause 48. The antioxidant blend of any of clauses 39 through 47, wherein the phosphite antioxidant reacts with unstable compounds in the polymer material.

[0052] Clause 49. The antioxidant blend of any of clauses 39 through 48, wherein the unstable compounds are formed by a second reaction of the polymer material with the oxygen-centered free radicals.Docket No. 2919-3.01 8

[0053] Clause 50. The antioxidant blend of any of clauses 39 through 49, wherein the lactone-based antioxidant comprises a compound according to the formula:

[0054] Clause 51. The antioxidant blend of any of clauses 39 through 50, wherein R1, R2, and R3 are each independently chosen from a group consisting of a hydrocarbon, an alkyl, an aryl, an oligomer, and an additional polymer.

[0055] Clause 52. The antioxidant blend of any of clauses 39 through 51, wherein the lactone-based antioxidant comprises a compound according to the formula:

[0056] Clause 53. The antioxidant blend of any of clauses 39 through 52, wherein the phenolic antioxidant comprises a compound according to the formula:Docket No. 2919-3.01 9

[0057] Clause 54. The antioxidant blend of any of clauses 39 through 53, wherein the phosphite antioxidant comprises a compound according to the formula:

[0058] Clause 55. The antioxidant blend of any of clauses 39 through 54, wherein the phosphite antioxidant comprises a compound according to the formula:Docket No. 2919-3.01 10

[0059] Clause 56. The antioxidant blend of any of clauses 39 through 55, wherein the phenolic antioxidant constitutes 40% to 65% of the antioxidant blend.

[0060] Clause 57. The antioxidant blend of any of clauses 39 through 56, wherein the phosphite antioxidant constitutes 25% to 50% of the antioxidant blend.

[0061] Clause 58. The antioxidant blend of any of clauses 39 through 57, wherein the lactone-based antioxidant constitutes up to 35% of the antioxidant blend.

[0062] Clause 59. The antioxidant blend of any of clauses 39 through 58, wherein the phenolic antioxidant constitutes 42.5% to 47.5% of the antioxidant blend.

[0063] Clause 60. The antioxidant blend of any of clauses 39 through 59, wherein the phosphite antioxidant constitutes 42.5% to 47.5% of the antioxidant blend.

[0064] Clause 61. The antioxidant blend of any of clauses 39 through 60, wherein the lactone-based antioxidant constitutes 5% to 15% of the antioxidant blend.

[0065] Clause 62. The antioxidant blend of any of clauses 39 through 61, wherein the phenolic antioxidant constitutes 30% to 75% of the antioxidant blend.

[0066] Clause 63. The antioxidant blend of any of clauses 39 through 62, wherein the phenolic antioxidant constitutes 50% to 55% of the antioxidant blend.

[0067] Clause 64. The antioxidant blend of any of clauses 39 through 63, wherein the phenolic antioxidant constitutes 33.3% of the antioxidant blend.Docket No. 2919-3.01 11

[0068] Clause 65. The antioxidant blend of any of clauses 39 through 64, wherein the phosphite antioxidant constitutes 5% to 70% of the antioxidant blend.

[0069] Clause 66. The antioxidant blend of any of clauses 39 through 65, wherein the phosphite antioxidant constitutes 30% to 45% of the antioxidant blend.

[0070] Clause 67. The antioxidant blend of any of clauses 39 through 66, wherein the phosphite antioxidant constitutes 33.3% of the antioxidant blend.

[0071] Clause 68. The antioxidant blend of any of clauses 39 through 67, wherein the lactone-based antioxidant constitutes up to 25% of the antioxidant blend.

[0072] Clause 69. The antioxidant blend of any of clauses 39 through 68, wherein the lactone-based antioxidant constitutes up to 20% of the antioxidant blend.

[0073] Clause 70. The antioxidant blend of any of clauses 39 through 69, wherein the lactone-based antioxidant constitutes up to 15% of the antioxidant blend.

[0074] Clause 71. A conveyor belt comprising: a belt manufactured from a material, the material comprising: a base material; and an antioxidant blend, wherein the antioxidant blend comprises: a lactone-based antioxidant; a phenolic antioxidant; and a phosphite antioxidant.

[0075] Clause 72. The conveyor belt of clause 71, wherein the conveyor belt is for use in a processing system.

[0076] Clause 73. The conveyor belt of any of clauses 71 or 72, wherein the belt is configured to move one or more objects through the processing system.

[0077] Clause 74. The conveyor belt of any of clauses 71 through 73, wherein the base material comprises a polymer.Docket No. 2919-3.01 12

[0078] Clause 75. The conveyor belt of any of clauses 71 through 74, wherein the antioxidant blend is dispersed throughout the base material.

[0079] Clause 76. The conveyor belt of any of clauses 71 through 75, wherein the antioxidant blend is configured to reduce degradation of the base material.

[0080] Clause 77. The conveyor belt of any of clauses 71 through 76, wherein the lactone-based antioxidant reacts with carbon-centered free radicals in the base material.

[0081] Clause 78. The conveyor belt of any of clauses 71 through 77, wherein the lactone-based antioxidant reacts with carbon-centered free radicals in the polymer.

[0082] Clause 79. The conveyor belt of any of clauses 71 through 78, wherein the carbon-centered free radicals are formed by a scission of the polymer caused by at least one of heat, shear, entrapped oxygen, and catalyst residue.

[0083] Clause 80. The conveyor belt of any of clauses 71 through 79, wherein the phenolic antioxidant reacts with oxygen-centered free radicals in the base material.

[0084] Clause 81. The conveyor belt of any of clauses 71 through 80, wherein the phenolic antioxidant reacts with oxygen-centered free radicals in the polymer.

[0085] Clause 82. The conveyor belt of any of clauses 71 through 81, wherein the oxygen-centered free radicals are formed by a first reaction of the polymer with the carbon-centered free radicals and oxygen.

[0086] Clause 83. The conveyor belt of any of clauses 71 through 82, wherein the phosphite antioxidant reacts with unstable compounds in the base material.

[0087] Clause 84. The conveyor belt of any of clauses 71 through 83, wherein the phosphite antioxidant reacts with unstable compounds in the polymer.Docket No. 2919-3.01 13

[0088] Clause 85. The conveyor belt of any of clauses 71 through 84, wherein the unstable compounds are formed by a second reaction of the polymer with the oxygencentered free radicals.

[0089] Clause 86. The conveyor belt of any of clauses 71 through 85, wherein the lactone-based antioxidant comprises a compound according to the formula:

[0090] Clause 87. The conveyor belt of any of clauses 71 through 86, wherein R1, R2, and R3 are each independently chosen from a group consisting of a hydrocarbon, an alkyl, an aryl, an oligomer, and an additional polymer.

[0091] Clause 88. The conveyor belt of any of clauses 71 through 87, wherein the lactone-based antioxidant comprises a compound according to the formula:Docket No. 2919-3.01 14

[0092] Clause 89. The conveyor belt of any of clauses 71 through 88, wherein the phenolic antioxidant comprises a compound according to the formula:

[0093] Clause 90. The conveyor belt of any of clauses 71 through 89, wherein the phosphite antioxidant comprises a compound according to the formula:Docket No. 2919-3.01 15

[0094] Clause 91. The conveyor belt of any of clauses 71 through 90, wherein the phosphite antioxidant comprises a compound according to the formula:

[0095] Clause 92. The conveyor belt of any of clauses 71 through 91, wherein the antioxidant blend constitutes 10% to 0.02% of the material.

[0096] Clause 93. The conveyor belt of any of clauses 71 through 92, wherein the antioxidant blend constitutes 5% to 0.02% of the material.

[0097] Clause 94. The conveyor belt of any of clauses 71 through 93, wherein the antioxidant blend constitutes 1% to 0.02% of the material.Docket No. 2919-3.01 16

[0098] Clause 95. The conveyor belt of any of clauses 71 through 94, wherein the phenolic antioxidant constitutes 30% to 75% of the antioxidant blend.

[0099] Clause 96. The conveyor belt of any of clauses 71 through 95, wherein the phenolic antioxidant constitutes 50% to 55% of the antioxidant blend.

[0100] Clause 97. The conveyor belt of any of clauses 71 through 96, wherein the phenolic antioxidant constitutes 33.3% of the antioxidant blend.

[0101] Clause 98. The conveyor belt of any of clauses 71 through 97, wherein the phosphite antioxidant constitutes 5% to 70% of the antioxidant blend.

[0102] Clause 99. The conveyor belt of any of clauses 71 through 98, wherein the phosphite antioxidant constitutes 30% to 45% of the antioxidant blend.

[0103] Clause 100. The conveyor belt of any of clauses 71 through 99, wherein the phosphite antioxidant constitutes 33.3% of the antioxidant blend.

[0104] Clause 101. The conveyor belt of any of clauses 71 through 100, wherein the lactone-based antioxidant constitutes up to 35% of the antioxidant blend.

[0105] Clause 102. The conveyor belt of any of clauses 71 through 101, wherein the lactone-based antioxidant constitutes up to 25% of the antioxidant blend.

[0106] Clause 103. The conveyor belt of any of clauses 71 through 102, wherein the lactone-based antioxidant constitutes up to 20% of the antioxidant blend.

[0107] Clause 104. The conveyor belt of any of clauses 71 through 103, wherein the lactone-based antioxidant constitutes up to 15% of the antioxidant blend.

[0108] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, norDocket No. 2919-3.01 17is it intended to be used to limit the scope of the claimed subject matter. Other aspects and advantages of the present disclosure will be apparent from the following detailed description of the embodiments and the accompanying drawing figures.BRIEF DESCRIPTION OF THE DRAWINGS

[0109] Embodiments of the present disclosure are described in detail below with reference to the attached drawing figures, wherein:

[0110] FIG. 1 depicts an exemplary flow diagram depicting the degradation and stabilization of polymers according to some embodiments;

[0111] FIG. 2 depicts an exemplary polymeric material comprising an antioxidant blend according to some embodiments; and

[0112] FIG. 3 depicts an exemplary conveyor belt manufactured with the polymeric material depicted in FIG. 2 according to some embodiments.

[0113] The drawing figures do not limit the present disclosure to the specific embodiments disclosed and described herein. The drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure.DETAILED DESCRIPTION

[0114] The following detailed description of embodiments of the present disclosure references the accompanying drawings that illustrate specific embodiments in which the present disclosure can be practiced. The embodiments are intended to describe aspects of the present disclosure in sufficient detail to enable those skilled in the art to practiceDocket No. 2919-3.01 18the present disclosure. Other embodiments can be utilized, and changes can be made without departing from the scope of the present disclosure. Therefore, the following detailed description is not to be taken in a limiting sense. The scope of embodiments of the present disclosure is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled.

[0115] In this description, references to "one embodiment," "an embodiment," or "embodiments" mean that the feature or features being referred to are included in at least one embodiment of the technology. Separate reference to "one embodiment," "an embodiment," or "embodiments" in this description do not necessarily refer to the same embodiment and are also not mutually exclusive unless so stated and / or except as will be readily apparent to those skilled in the art from the description. For example, a feature, structure, or act described in one embodiment may also be included in other embodiments but is not necessarily included. Thus, the technology can include a variety of combinations and / or integrations of the embodiments described herein.

[0116] As used herein, bonds between atoms, molecules, and / or compounds may be represented by their symbols with a dash between the symbols. For example, a bond between a carbon molecule and a hydrogen molecule may be represented as “C-H.” As used herein, functional groups may be represented by a dash and their condensed formulas. For example, a methyl group may be represented as “-CH3” and an ethyl group may be represented using “-CH2-CH3.” As used herein, “R” may be used as a symbol to refer to a polymer, a hydrocarbon, or a functional group. For example, “R” may be the symbol for a generic polymer that could have varying chemical formulas. As used herein, “lactone-based antioxidants” may refer to antioxidants comprising one or more lactones.Docket No. 2919-3.01 19For example, “lactone-based antioxidants” may refer to an antioxidant having a 5-membered lactone (i.e., a y-lactone).

[0117] As used herein, “radicals” or “free radicals” may refer to an atom, molecule, and / or compound having an unpaired valence electron and may be represented using a dot next to the symbol of the atom, molecule, or compound having the free radical. For example, “R»” may refer to a hydrocarbon or polymer having a free radical. Further, as used herein, “oxygen-centered free radicals” may refer to oxygen molecules having an unbonded electron and may be represented using “O’.” Similarly, as used herein, “carbon-centered free radicals” may refer to carbon molecules having an unbonded electron and may be represented using “O.” As used herein, “scavenge free radicals” or “scavenging free radicals” may refer to reacting with a free radical to stabilize the free radical via proton donation or other suitable reactions. As used herein, numeric ranges may be inclusive to the numbers defining the range and include sub-ranges therein. For example, a range of “25% to 50%” may include 25%, 50%, and subranges, such as 35% to 40%.

[0118] As polymers degrade, carbon-centered free radicals and oxygen-centered free radicals are formed that cause further degradation of the polymers. The free radicals may change the color of the polymer and degrade the physical properties (i.e., mechanical strength) of the polymer over time. As described herein, antioxidant blends may be added to polymeric materials to scavenge both carbon-centered free radicals and oxygencentered free radicals to thereby reduce or prevent the oxidation and degradation of the polymeric materials and increase the service life of the polymeric materials. Further, embodiments of the present disclosure include antioxidants that remain stable at highDocket No. 2919-3.01 20temperatures (e.g., up to 220°F, up to 230°F, up to 240°F, up to 250°F, up to 260°F, up to 270°F, up to 280°F, up to 290°F, up to 300°F, or up to 305°F) and / or in humid conditions (e.g., greater than 50%, greater than 60%, greater than 70%, greater than 80%, or greater than 90% relative humidity). Accordingly, the antioxidant blends described herein may be utilized at high temperatures and in humid conditions, such as in polymers subject to pasteurization conditions. As described herein, polymers, such as polyolefins, may include the antioxidant blends described herein to increase the service life of the polymers. Further, polymers that include the disclosed antioxidant blends may be utilized to manufacture products such as conveyor belts.

[0119] FIG. 1 depicts an example of flow diagram 10 depicting the degradation and stabilization of polymers (depicted as “R” in FIG. 1). In some embodiments, flow diagram 10 comprises a first degradation cycle 12 and a second degradation cycle 14. Flow diagram 10 begins at degradation step 16, in which carbon-centered free radicals are created from a polymer. At degradation step 16, polymers may form free radicals due to high temperatures, shear, entrapped oxygen, and catalyst residues. Further, polymers may form carbon-centered free radicals via C-C and / or C-H bond scission of the polymer chains. For example, high temperatures may cause the scission of a C-C bond and thereby form carbon-centered free radicals.

[0120] The formation of free radicals causes further degradation of polymers via first degradation cycle 12 and second degradation cycle 14 of flow diagram 10. First degradation cycle 12 comprises degradation step 18 and degradation step 20, and second degradation cycle 14 comprises degradation step 22 and degradation step 24. Degradation steps 18, 20, 22, and 24 of flow diagram 10 are depicted with solid arrowsDocket No. 2919-3.01 21showing the reaction of free radicals and / or unstable compounds that further degrade the polymer.

[0121] At degradation step 18, the carbon-centered free radicals may further react with other polymer molecules and oxygen to form oxygen-centered free radicals in the form of peroxyl radicals (i.e., ROO*). At degradation step 20, the peroxyl radicals may react with other polymer molecules to form unstable compounds, such as hydroperoxides (i.e., ROOH), and carbon-centered free radicals (i.e., R*). Since degradation step 20 forms carbon-centered free radicals, degradation step 18 may repeat after degradation step 20. Accordingly, first degradation cycle 12 comprises degradation steps 18 and 20 that may repeat and cause further degradation of polymers.

[0122] The unstable compounds formed by degradation step 20 may be hydroperoxides that undergo decomposition by heat, UV light, and / or reaction with catalyst residues or other metallic impurities. As used herein, “unstable compounds” may refer to any compound that leads to further degradation of the polymer. For example, an unstable compound may be a hydroperoxide that leads to further formation of free radicals. At degradation step 22, the unstable compounds (e.g., hydroperoxides) decompose to form oxygen-centered free radicals in the form of alkoxy radicals (i.e., RO*) and hydroxy radicals (i.e., *OH). At degradation step 24, the alkoxy radicals and hydroxy radicals lead to further polymer chain scission to form additional carbon-centered free radicals and unstable compounds (e.g., hydroperoxides). The unstable compounds formed by degradation step 24 may further decompose and thus repeat degradation step 24. Accordingly, second degradation cycle 14 comprises degradation steps 22 and 24 that may repeat and cause further degradation of polymers.Docket No. 2919-3.01 22

[0123] As described above, the degradation of polymers leads to the formation of free radicals and unstable compounds that further degrade the polymers. For example, free radicals may degrade the polymer by scissioning polymer chains. As polymers degrade, the physical properties and long-term durability of the polymers also degrade. Specifically, the degradation of polymers may affect any combination of color, mechanical strength, or service life of the polymers. For example, the scission of polymer chains and the formation of free radicals may cause color changes in the polymer. Further, the scission of polymer chains and the resulting formation of free radicals may degrade the mechanical strength of the polymer and thus decrease the service life of the polymer. Accordingly, the reactions of free radicals with polymers and the degradation of polymers are undesirable.

[0124] To eliminate undesirable polymer degradation, single antioxidants or blends of antioxidants may be added to polymers to eliminate or reduce polymer degradation by providing one or more stabilization steps to stabilize unstable molecules and / or compounds in the polymers. As depicted in FIG. 1, flow diagram 10 may comprise stabilization step 26, stabilization step 28, stabilization step 30, and stabilization step 32. Stabilization steps 26, 28, 30, and 32 of flow diagram 10 are depicted with dashed arrows showing the reaction and stabilization of free radicals and / or unstable compounds that form inactive products. As depicted in flow diagram 10, stabilization steps 26, 28, 30, and 32 may avoid the degradation steps of first degradation cycle 12 and second degradation cycle 14 by the use of antioxidants to stabilize free radicals and / or unstable compounds that would otherwise degrade the polymer.

[0125] At stabilization step 26, at least a portion of the peroxyl radicals formed by degradation step 18 is stabilized to form inactive products. By reacting the peroxylDocket No. 2919-3.01 23radicals to form inactive products, degradation step 20 may be at least partially avoided, such that first degradation cycle 12 may be disrupted. In some embodiments, phenolic antioxidants may be utilized to react with the peroxyl radicals to form inactive products, thereby stabilizing the peroxyl radicals. For example, a phenolic antioxidant may donate a proton to the peroxyl radical to stabilize the peroxyl radical thereby. Phenolic antioxidants are described in more detail below in FIG. 2. Alternatively, thiosynergists (i.e., thioester-based antioxidants) may be utilized to stabilize the peroxyl radical. In some embodiments, stabilization step 26 stabilizes the oxygen-centered free radical of the peroxyl radical to prevent degradation step 20 from occurring and further degrading polymers.

[0126] At stabilization step 28, at least a portion of the unstable compounds (e.g., hydroperoxides) formed by degradation step 20 is stabilized to form inactive products. By reacting the unstable compounds to form inactive products, degradation step 22 may be at least partially avoided, such that second degradation cycle 14 may be disrupted. In some embodiments, phosphite antioxidants may be utilized to react with the unstable compounds (e.g., hydroperoxides) to form inactive ROH products, thereby stabilizing the unstable compounds. Phosphite antioxidants are described in more detail below in FIG.2. In some embodiments, stabilization step 28 stabilizes the unstable compounds (e.g., hydroperoxides) to prevent degradation step 22 from occurring and further degrading polymers.

[0127] At stabilization step 30, at least a portion of the alkoxy radicals and hydroxy radicals formed by degradation step 22 is stabilized to form inactive products. By reacting the alkoxy radicals and hydroxy radicals to form inactive products, degradation step 24Docket No. 2919-3.01 24may be at least partially avoided, such that second degradation cycle 14 may be disrupted. In some embodiments, phenolic antioxidants may be utilized to react with the alkoxy radicals and hydroxy radicals to form inactive ROH and H2O products, respectively. For example, a phenolic antioxidant may donate a proton to an alkoxy radical to form inactive ROH and / or to a hydroxy radical to form inactive H2O. In some embodiments, stabilization step 30 stabilizes the oxygen-centered free radicals of the alkoxy radical and hydroxy radical to prevent degradation step 24 from occurring and further degrading polymers.

[0128] At stabilization step 32, at least a portion of the carbon-centered free radicals formed by degradation steps 16, 20, and / or 24 is stabilized to form inactive products. By reacting the carbon-centered free radicals to form inactive products, degradation step 18 may be at least partially avoided, such that first degradation cycle 12 may be disrupted. In some embodiments, lactone-based antioxidants may be utilized to react with the carbon-centered free radicals to form inactive products. For example, a lactone-based antioxidant may donate a proton to a carbon-centered free radical to form an inactive compound. Lactone-based antioxidants are described in more detail below in FIG. 2. In some embodiments, stabilization step 32 stabilizes the carbon-centered free radical to prevent degradation step 18 from occurring and further degrading polymers.

[0129] As described above, the use of antioxidants to stabilize unstable compounds and free radicals is known. However, current antioxidants and antioxidant blends do not allow for each of the stabilization steps (e.g., stabilization steps 26, 28, 30, and 32) to occur. Embodiments of the present disclosure provide antioxidant blends that allow for each of the above-described stabilization steps to occur. Specifically, the antioxidantDocket No. 2919-3.01 25blends described herein include a phenolic antioxidant, a phosphite antioxidant, and a lactone-based antioxidant that allow for each of the stabilization steps to occur and increase the service life of polymers having the antioxidant blends. Additionally, the antioxidant blends described herein may remain stable at high temperatures and in humid conditions, such as pasteurization conditions or autoclave conditions.

[0130] FIG. 2 depicts an example of a polymeric material 34 comprising a base material 36 and an antioxidant blend 38. Antioxidant blend 38 may be dispersed throughout base material 36 and comprise a phenolic antioxidant 40, a phosphite antioxidant 42, and a lactone-based antioxidant 44 described in more detail below. The disclosed antioxidant blends allow for each of stabilization step 26, stabilization step 28, stabilization step 30, and stabilization step 32 to occur without restricting the effectiveness of each antioxidant in the antioxidant blends. Polymeric material 34 comprises antioxidant blend 38, which may allow for the polymeric material to be utilized at high temperatures (e.g., greater than 145°F, greater than 160°F, greater than 176°F, greater than 200°F, or greater than 212°F and / or up to 220°F, up to 230°F, up to 240°F, up to 250°F, up to 260°F, up to 270°F, up to 280°F, up to 290°F, up to 300°F, or up to 305°F) and / or in humid conditions (e.g., greater than 50%, greater than 60%, greater than 70%, greater than 80%, or greater than 90% relative humidity).

[0131] Polymeric material 34 comprising antioxidant blend 38 may be utilized in any food and / or industrial processing systems. For example, polymeric material 34 comprising antioxidant blend 38 may be utilized in any of pasteurization processes, autoclave processes, steam sterilization processes, hot water sanitization processes, dishwashing processes, blanching processes, or cooking processes. Embodiments are contemplatedDocket No. 2919-3.01 26in which polymeric material 34 comprising antioxidant blend 38 may be utilized in any type of chemical sterilization process now known or later developed, including, but not limited to, chemical immersion, chemical spraying, and chemical vaporization sterilization.

[0132] In some embodiments, base material 36 may include polymers, such as thermoplastics, thermosets, and / or elastomers. Specifically, base material 36 may include a polyolefin material, such as a polyethylene material, a polypropylene material, a polybutene material, a polymethylpentene material. For example, base material 36 may be a polypropylene material configured to withstand high temperatures and humid conditions.

[0133] Base material 36 may constitute a large portion (e.g., greater than 90%, greater than 92.5%, greater than 95%, greater than 97.5%, or greater than 99%) of polymeric material 34. In some embodiments, base material 36 may constitute greater than 75%, greater than 80%, greater than 85%, greater than 90%, greater than 92.5%, greater than 95%, greater than 97.5%, greater than 99%, greater than 99.5%, or greater than 99.9% of polymeric material 34. In some embodiments, base material 36 may constitute 80% to 99.9%, 85% to 99%, or 90% to 97.5% of polymeric material 34. For example, base material 36 may constitute 93%, 95%, or 97% of polymeric material 34. Embodiments are contemplated in which the percentage of the base material may depend, at least in part, on the base material used. For example, if base material 36 is a polypropylene material, base material 36 may constitute 95% of the polymeric material 34.

[0134] Antioxidant blend 38 may be dispersed throughout base material 36 and constitute a small portion (e.g., less than 10%, less than 5%, less than 2.5%, or less thanDocket No. 2919-3.01 271%) of polymeric material 34. In some embodiments, antioxidant blend 38 may constitute up to 15%, up to 10%, up to 7.5%, up to 7%, up to 6%, up to 5%, up to 2.5%, up to 1%, up to 0.5%, or up to 0.1% of polymeric material 34. In some embodiments, antioxidant blend 38 may constitute 10% to 0.02%, 7.5% to 0.02%, 5% to 0.02%, 1% to 0.02%, 0.5% to 0.02%, or 0.15% to 0.02% of polymeric material 34. For example, antioxidant blend 38 may constitute 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 2.5%, 5%, or 7% of polymeric material 34. Embodiments are contemplated in which the percentage of the antioxidant blend 38 may depend, at least in part, on the base material used. For example, if base material 36 is a polypropylene material, antioxidant blend 38 may constitute less than 1% of the polymeric material 34.

[0135] As described above, antioxidant blend 38 comprises a phenolic antioxidant 40, a phosphite antioxidant 42, and a lactone-based antioxidant 44 that each facilitates the stabilization of polymeric material 34. Phenolic antioxidant 40 facilitates the stabilization of polymeric material 34. For example, phenolic antioxidant 40 may react with the oxygencentered free radicals to form inactive products as described above in stabilization steps 26 and 30 of flow diagram 10 depicted in FIG. 1. In some embodiments, phenolic antioxidant 40 constitutes greater than 30%, greater than 35%, greater than 40%, greater than 45%, greater than 50%, greater than 55%, greater than 60%, greater than 65%, greater than 70%, or greater than 75% of antioxidant blend 38. In some embodiments, phenolic antioxidant 40 constitutes 30% to 75%, 35% to 70%, 30% to 65%, 40% to 65%, 45% to 60%, 42.5% to 47.5%, or 50% to 55% of antioxidant blend 38. For example, phenolic antioxidant 40 may constitute 33.3%, 37.5%, 40%, 42.5%, 51%, or 57% of antioxidant blend 38.Docket No. 2919-3.01 28

[0136] In some embodiments, phenolic antioxidant 40 may be any phenolic antioxidant known in the art. However, typical phenolic antioxidants may be prone to hydrolysis due to comprising one or more ester groups that may be easily hydrolyzed at high temperatures and in humid conditions. For example, a typical phenolic antioxidant may be an ester-based compound according to the formula:

[0137] Accordingly, phenolic antioxidant 40 may be a non-ester-based phenolic antioxidant so as to be more resistant to hydrolyzation than typical phenolic antioxidants. In some embodiments, phenolic antioxidant 40 may be a sterically hindered compound to resist hydrolyzation further. Therefore, phenolic antioxidant 40 may be utilized in high temperature and humid conditions, such as in pasteurization conditions.

[0138] In some embodiments, phenolic antioxidant 40 may be a 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene according to the formula:Docket No. 2919-3.01 291,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene is a non-ester-based and sterically hindered phenolic antioxidant and may be used in high temperature and humid conditions. Additionally, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene has a similar oxidation induction time (OIT) and a higher antioxidant depletion rate compared to typical phenolic antioxidants used to stabilize polymers. As used herein, OIT may refer to the time it takes for a material to begin exothermic decomposition after being exposed to an oxidizing gas at a high temperature (e.g., above 350°F or at 392°F). Further, as used herein, Onset OIT may refer to the time it takes for a material to begin oxidizing after being exposed to an oxidizing gas at a high temperature (e.g., above 350°F or at 392°F). As used herein, the antioxidant depletion rate may refer to the rate at which an antioxidant is depleted.Docket No. 2919-3.01 30

[0139] Phosphite antioxidant 42 facilitates the stabilization of polymeric material 34. For example, phosphite antioxidant 42 may react with unstable compounds, such as hydroperoxides, to form inactive products as described above in stabilization step 28 of flow diagram 10 depicted in FIG. 1. In some embodiments, phosphite antioxidant 42 may constitute 5% to 70%, 10% to 65%, 15% to 60%, 20% to 55%, 25% to 50%, 30% to 45%, or 35% to 40% of antioxidant blend 38. For example, phosphite antioxidants may constitute 28%, 33.3%, 34%, 37.5%, 40%, or 42.5% of antioxidant blend 38.

[0140] In some embodiments, phosphite antioxidant 42 may include any phosphite antioxidant known in the art. Specifically, phosphite antioxidant 42 may be a bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite according to the formula:Alternatively, phosphite antioxidant 42 may be a bis(2,4-dicumylphenyl) pentaerythritol diphosphite according to the formula:Docket No. 2919-3.01 31Bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite and bis(2,4-dicumylphenyl) pentaerythritol diphosphite each have a substantially higher (e.g., over 3 times higher) OIT and better processing stability compared to typical phosphite antioxidants used to stabilize polymers. For example, bis(2,4-dicumylphenyl) pentaerythritol diphosphite has 3.5 times greater OIT compared to typical phosphite antioxidants. A higher OIT may be indicative of greater stability of the material. As used herein, processing stability may refer to the extent of polymer degradation due to multiple extrusions of a polymer, such as polypropylene. A higher processing stability may be indicative of a lower extent of degradation after extruding the polymer multiple times.

[0141] Lactone-based antioxidant 44 may facilitate the stabilization of polymeric material 34. For example, lactone-based antioxidant 44 may react with carbon-centered free radicals to form inactive products as described above in stabilization step 32 of flow diagram 10 depicted in FIG. 1. In some embodiments, lactone-based antioxidant 44 may constitute up to 35%, up to 33.3%, up to 30%, up to 25%, up to 20%, up to 15%, up to 10%, or up to 5% of antioxidant blend 38. In some embodiments, lactone-based antioxidant 44 may constitute 1% to 35%, 5% to 35%, 10% to 35%, 15% to 35%, 1% to 25%, 5% to 20%, or 10% to 15% of antioxidant blend 38. For example, lactone-based antioxidants may constitute 15%, 20%, 25%, or 33.3% of antioxidant blend 38.Docket No. 2919-3.01 32

[0142] Lactone-based antioxidant 44 is an antioxidant comprising one or more lactone groups. For example, lactone-based antioxidant 44 may comprise any combination of a 3-membered lactone group (i.e., a-lactone), a 4-membered lactone group (i.e., p-lactone), a 5-membered lactone group (i.e., y-lactone), a 6-membered lactone group (i.e., 5-lactone), a 7-membered lactone group (i.e., c-lactone), or a lactone group comprising 8 or more members. In some embodiments, lactone-based antioxidant 44 may be any known lactone-based antioxidant known in the art. For example, lactone-based antioxidant 44 may be similar to lactone-based antioxidants described in U. S. Patent No.8,840,810.

[0143] In some embodiments, lactone-based antioxidant 44 may be an arylbenzofuranone compound according to the formula:wherein Ri, R2, and R3 may be any combination of functional groups. Specifically, R1, R2, and R3 may each be independently chosen from a group consisting of a hydrocarbon, an alkyl, an alkenyl, an alkynyl, an aryl, a hydroxyl, a ketone, an aldehyde, an oligomer, and a polymer, as well as combinations thereof. For example, R1 and R2 may be a tert-butyl group, and R3 may be a tert-butyl phenol group. Accordingly, lactone-based antioxidantDocket No. 2919-3.01 33may be a 4-tert-butyl-2-(5-tert-butyl-2-oxo-3H-benzofuran-3-yl)phenyl-3,5-di-tert-butyl-4-hydroxybenzoate according to the formula:The above-described arylbenzofuranone compounds may improve processing stability and high-temperature processing of polymeric material 34, increase the OIT of antioxidant blend 38, and regenerate phenolic antioxidant 40 of antioxidant blend 38.

[0144] Lactone-based antioxidant 44 may be effective at temperatures above 300°F, above 400°F, above 500°F, or above 600°F. For example, lactone-based antioxidant 44 may be effective at temperatures up to 614°F. Comparatively, typical antioxidants start to lose effectiveness at 248°F. Further, lactone-based antioxidants may not be prone to hydrolysis. Such qualities allow for lactone-based antioxidant 44 to be utilized at high temperatures and in humid conditions, such as pasteurization conditions.

[0145] Lactone-based antioxidant 44 may donate protons to the other antioxidants of antioxidant blend 38 (e.g., phenolic antioxidant 40 and / or phosphite antioxidant 42). In some embodiments, after a phenolic antioxidant has donated a proton to an oxygencentered free radical, lactone-based antioxidant 44 may donate a proton to phenolic Docket No. 2919-3.01 34antioxidant 40 to regenerate the phenolic antioxidant 40. Accordingly, lactone-based antioxidant 44 synergizes with at least the phenolic antioxidant 40 and increases the longevity of phenolic antioxidant 40 of antioxidant blend 38 and the long-term durability of polymeric material 34.

[0146] Compared to traditional antioxidants, the dosage of lactone-based antioxidant 44 may be reduced by at least 50% compared to typical antioxidant dosages and remain effective. Accordingly, lactone-based antioxidant 44 facilitates the compatibility of the antioxidants in antioxidant blend 38 and reduces the cost of antioxidant blend 38. Further, lactone-based antioxidant 44 may improve the melt flow and color retention properties. For example, polymeric material 34 having antioxidant blend 38 that comprises lactone-based antioxidant 44 may have a decreased viscosity when melted, an increased molten flow rate, and an improved color retention property.

[0147] In some embodiments, polymeric material 34 may be formed by dissolving the antioxidant blend 38 within base material 36. For example, phenolic antioxidant 40, phosphite antioxidant 42, and lactone-based antioxidant 44 may be soluble in base material 36, such that the antioxidants are dispersed throughout base material 36. In some embodiments, antioxidant blend 38 may be at least partially or fully dissolved in base material 36.

[0148] In some embodiments, antioxidant blend 38 may comprise a ratio of phenolic antioxidant 40 to phosphite antioxidant 42 to lactone-based antioxidant 44 within a range of within a range of 1:1:1 to 3.8:1.87:1, within a range of 1:1:1 to 3.4:2.27:1, within a range of 1:1:1 to 3:3:1, within a range of 1:1:1 to 3:3:2, or within a range of 1:1:1 to 3:3:1.5. For example, the ratio of phenolic antioxidant 40 to phosphite antioxidant 42 to lactone-basedDocket No. 2919-3.01 35antioxidant 44 may be 1:1:1, 3:3:2, or 3:3:1.5. In another example, the ratio of phenolic antioxidant 40 to phosphite antioxidant 42 to lactone-based antioxidant 44 may be 3:3:1, 3.4:2.27:1, or 3.8:1.87:1. The ratios described herein may be based on a weight basis, a volumetric basis, or a molar basis. For example, a ratio of 1:1:1 may refer to a weight ratio of 1:1:1, a volumetric ratio of 1:1:1, or a molar ratio of 1:1:1.

[0149] Embodiments are contemplated in which antioxidant blend 38 may include one or more phenolic antioxidants. For example, antioxidant blend 38 may comprise a combination of non-ester-based and / or sterically hindered phenolic antioxidants. Embodiments are contemplated in which antioxidant blend 38 may include one or more phosphite antioxidants. For example, antioxidant blend 38 may comprise a combination of phosphite antioxidants, such as the phosphite antioxidants described herein. Embodiments are contemplated in which antioxidant blend 38 may include one or more lactone-based antioxidants. For example, antioxidant blend 38 may comprise a combination of lactone-based antioxidants, such as the lactone-based antioxidants described herein.

[0150] Polymeric material 34 may further comprise additional additives and / or antioxidants. For example, polymeric material 34 may comprise a secondary polymer and / or a colorant configured to change a physical feature (e.g., strength or color) of polymeric material 34. For example, polymeric material 34 may comprise a secondary polymer material to change the strength, melting point, and / or flexibility of polymeric material 34. In another example, polymeric material 34 may comprise colorants configured to change the color of polymeric material 34. In some embodiments, acid scavengers may be added to polymeric material 34 to neutralize acidic impurities inDocket No. 2919-3.01 36polymeric material 34. For example, polymeric material 34 may include calcium stearate and / or calcium distearate to scavenge acidic impurities within polymeric material 34.

[0151] FIG. 3 depicts an example of a conveyor belt system 46 comprising a belt 48 and one or more pulleys 50. Belt 48 may deliver one or more objects from a loading point to a transfer point. One or more pulleys 50 may be coupled to one or more motors to move belt 48 along one or more pulleys 50. As depicted in FIG. 3 via the dashed circle, belt 48 may be manufactured using polymeric material 34 as described in FIG. 2. Accordingly, conveyor belt system 46 may be utilized at high temperatures (e.g., greater than 145°F, greater than 160°F, greater than 176°F, greater than 200°F, or greater than 212°F and / or up to 220°F, up to 230°F, up to 240°F, up to 250°F, up to 260°F, up to 270°F, up to 280°F, up to 290°F, up to 300°F, or up to 305°F) and / or in humid conditions (e.g., greater than 50%, greater than 60%, greater than 70%, greater than 80%, or greater than 90% relative humidity). Further, belt 48 of conveyor belt system 46 has an increased long-term durability and service life due to the antioxidant blend 38 of polymeric material 34.

[0152] Conveyor belt system 46 may be utilized in any food and / or industrial processing systems. In some embodiments, conveyor belt system 46 may be utilized in any of pasteurization processes, autoclave processes, steam sterilization processes, hot water sanitization processes, dishwashing processes, blanching processes, or cooking processes, as well similar processes that subject conveyor belt system 46 to high temperature and / or high humidity conditions. For example, conveyor belt system 46 may be received by a pasteurizer and move one or more objects through the pasteurizer. Embodiments are contemplated in which conveyor belt system 46 may be utilized in anyDocket No. 2919-3.01 37type of chemical sterilization process now known or later developed, including, but not limited to, chemical immersion, chemical spraying, and chemical vaporization sterilization. For example, conveyor belt system 46 may contact or be at least partially submerged in one or more chemicals.

[0153] Embodiments are contemplated in which conveyor belt system 46 may be any type of conveyor belt system known in the art. For example, conveyor belt system 46 may be a modular belt conveyor system comprising a belt made of modular portions. In another example, conveyor belt system 46 may include horizontal, vertical, inclined, and / or curved sections such that belt 48 may move horizontally, vertically, at an incline, and / or along a curve.

[0154] Embodiments are contemplated in which other products may be manufactured using polymeric material 34 as described herein to increase the oxidation resistance and long-term durability of the product. For example, polymeric material 34 may be utilized to manufacture containers, bottles, clothing, roofing materials, ropes, carpets, automotive parts, toys, piping and / or drinking straws.EXAMPLESExample 1:

[0155] A first exemplary antioxidant blend comprises a phenolic antioxidant, a phosphite antioxidant, and a lactone-based antioxidant. The phenolic antioxidant of the first exemplary antioxidant blend is a sterically hindered 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene according to the formula:Docket No. 2919-3.01 38The phosphite antioxidant of the first exemplary antioxidant blend is a bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite according to the formula:Docket No. 2919-3.01 39The lactone-based antioxidant of the first exemplary antioxidant blend is a 4-tert-butyl-2- (5-tert-butyl-2-oxo-3H-benzofuran-3-yl)phenyl-3,5-di-tert-butyl-4-hydroxybenzoate according to the formula:Example 2:Docket No. 2919-3.01 40

[0156] A second exemplary antioxidant blend comprises a phenolic antioxidant, a phosphite antioxidant, and a lactone-based antioxidant. The phenolic antioxidant of the second exemplary antioxidant blend is a 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene according to the formula:The phosphite antioxidant of the second exemplary antioxidant blend is a bis(2,4-dicumylphenyl) pentaerythritol diphosphite according to the formula:Docket No. 2919-3.01 41The lactone-based antioxidant of the second exemplary antioxidant blend is a 4-tert-butyl- 2-(5-tert-butyl-2-oxo-3H-benzofuran-3-yl)phenyl-3,5-di-tert-butyl-4-hydroxybenzoate according to the formula:EXPERIMENTAL RESULTS

[0157] The above exemplary antioxidant blends were experimentally tested to quantify the impacts of adding the antioxidant blends to a polymeric material. The tested blends are described below in Table 1. Polypropylene (PP) was used as the polymeric material for each test described below. Formulation type “A” refers to the first exemplary antioxidant blend described above (i.e., an antioxidant blend comprising 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, and 4-tert-butyl-2-(5-tert-butyl-2-oxo-3H-benzofuran-3-yl)phenyl-3,5-di-tert-butyl-4-hydroxybenzoate), and formulation type “B” refers to the second exemplary antioxidant blend described above (i.e., an antioxidant blend comprising 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, bis(2,4-Docket No. 2919-3.01 42dicumylphenyl) pentaerythritol diphosphite, and 4-tert-butyl-2-(5-tert-butyl-2-oxo-3H-benzofuran-3-yl)phenyl-3,5-di-tert-butyl-4-hydroxybenzoate). Table 1 below presents the antioxidant (AO) content of each tested formulation, expressed as a percentage of the total formulation. Further, the ratios of the phenolic antioxidant to the phosphite antioxidant to the lactone antioxidant for each tested formulation are listed below in TableTable 1. Antioxidant Blend and Amount in the Tested Propylene Formulations AO Amount in AO Components Ratio in FormulationFormulation Formulation the AO BlendType% Phenolic: Phosphite: Lactone Control PP N / A N / A N / APP-AO-A11 A 0.1 3:3:1PP-AO-B11 B 0.1 3:3:1PP-AO-A13 A 0.1 3.4:2.27:1PP-AO-B13 B 0.1 3.4:2.27:1PP-AO-A21 A 0.2 3:3:1PP-AO-B21 B 0.2 3:3:1PP-AO-A23 A 0.2 3.4:2.27:1PP-AO-B23 B 0.2 3.4:2.27:1PP-AO-A31 A 0.3 3:3:1PP-AO-B31 B 0.3 3:3:1PP-AO-B32 B 0.3 3:3:1.5PP-AO-A41 A 0.4 3:3:1PP-AO-B41 B 0.4 3:3:1PP-AO-B42 B 0.4 3:3:1.5PP-AO-A51 A 0.5 3:3:1PP-AO-B51 B 0.5 3:3:1

[0158] Each of the above formulations were tested to determine the effect of the antioxidant blends on oxidation induction time (OIT) and onset OIT. As described above,Docket No. 2919-3.01 43OIT may refer to the time it takes for a material to begin exothermic decomposition after being exposed to an oxidizing gas at a high temperature (e.g., above 350°F or at 392°F). Further, onset OIT may refer to the time it takes for a material to begin oxidizing after being exposed to an oxidizing gas at a high temperature (e.g., above 350°F or at 392°F). The average onset OIT and the standard deviation (STDEV) for the average onset OIT for each formulation are below in Table 2. Further, the average OIT and the STDEV for the average OIT for each formulation are below in Table 3.Table 2. Oxidation Resistance Performance of Tested Formulations Onset OIT (min)FormulationAverage STDEV % ImprovementControl PP 2.89 0.55 0PP-AO-A11 11.45 3.33 296PP-AO-B11 14.34 9.65 396PP-AO-A13 22.61 12.74 682PP-AO-B13 17.51 9.29 506PP-AO-A21 55.12 8.84 1807PP-AO-B21 65.11 25.15 2153PP-AO-A23 41.1 17.59 1322PP-AO-B23 42.91 10.34 1385PP-AO-A31 67.55 7.78 2237PP-AO-B31 84.23 9.85 2815PP-AO-B32 84.67 7.75 2830PP-AO-A41 92.85 4.74 3113PP-AO-B41 98.55 18.41 3310PP-AO-B42 106.34 2.3 3580PP-AO-A51 85.54 13.07 2860PP-AO-B51 119.01 12.26 4018Docket No. 2919-3.01 44Table 3. Oxidation Resistance Performance of Tested FormulationsOIT (min)FormulationAverage STDEV % ImprovementControl PP 4.35 1.71 0PP-AO-A11 13.14 3.82 202PP-AO-B11 16.42 10.57 277PP-AO-A13 25.23 13.77 480PP-AO-B13 20.56 9.8 373PP-AO-A21 57.63 9.15 1225PP-AO-B21 69.33 24.4 1494PP-AO-A23 44.06 18.82 913PP-AO-B23 48.70 6.01 1020PP-AO-A31 69.98 6.9 1509PP-AO-B31 87.14 9.75 1903PP-AO-B32 88.64 7.43 1938PP-AO-A41 97.34 3.02 2138PP-AO-B41 103.18 15.98 2272PP-AO-B42 110.58 3.22 2442PP-AO-A51 90.99 12.02 1992PP-AO-B51 125.7 10.74 2790

[0159] As can be seen in Table 2 and Table 3, each of the tested formulations increased the onset OIT and the OIT compared to the control polypropylene without any antioxidants. Accordingly, adding the above tested formulations to a polypropylene material increased the time before the material began to oxidize and the time before the material began to exothermally decompose. Further, formulations having a larger percentage (e.g., 0.5%) of the above antioxidant blends further increased the onset OIT and the OIT compared to formulations having a smaller percentage (e.g., 0.1%) of the above antioxidant blends. Accordingly, adding a larger percentage of the above antioxidant blends to a polypropylene material increased the time before the materialDocket No. 2919-3.01 45began to oxidize and the time before the material began to exothermally decompose. Even further, adding formulation type B (i.e., Example 2 described above) to a polypropylene material tended to further increase the onset OIT and the OIT compared to adding formulation type A (i.e., Example 1 described above) to a polypropylene material.

[0160] Each of the above formulations was further tested to see the effect of the antioxidant blends on the mechanical properties (e.g., modulus, yield stress, and yield strain) of the polymeric material. As used herein, modulus (i.e., the modulus of elasticity) may refer to a material’s resistance to deforming elastically. For example, a material having a higher modulus value may be more rigid than a material having a lower modulus. As used herein, yield stress may refer to the amount of stress at which a material permanently deforms. For example, yield stress may refer to the point at which a material deforms plastically. As used herein, yield strain may refer to the percentage of deformation at which a material permanently deforms. The average modulus, yield stress, and yield strain and STDEV for the average modulus, yield stress, and yield strain for each formulation are below in Table 4. Further, the average stress at 1% strain, 3% strain, and 5% strain and the STDEV for the average stress for each formulation are recorded in Table 5 below. Finally, the change (A) in modulus, yield stress, and yield strain for each formulation compared to the control polypropylene is recorded in Table 6 below.Docket No. 2919-3.01 46Table 4. Mechanical Performance of Tested Formulations Modulus (ksi) Yield Stress (psi) Yield Strain (%) FormulationAverage STD EV Average STD EV Average STD EV Control PP 353 7 5812 24 6.39 0.1 PP-AO-A11 319 10 5713 23 6.68 0.13 PP-AO-B11 324 9 5721 65 6.18 0.28 PP-AO-A13 325 8 5840 20 6.67 0.15 PP-AO-B13 331 22 5785 16 6.81 0.25 PP-AO-A21 325 12 5721 41 6.95 0.13 PP-AO-B21 322 10 5677 18 6.55 0.25 PP-AO-A23 325 7 5794 42 6.24 0.11 PP-AO-B23 304 9 5656 31 6.70 0.16 PP-AO-A31 328 14 5767 61 6.56 0.32 PP-AO-B31 344 7 5776 29 5.96 0.09 PP-AO-B32 341 8 5753 24 6.06 0.1 PP-AO-A41 317 4 5723 52 7.22 0.12 PP-AO-B41 346 16 5742 34 5.86 0.32 PP-AO-B42 335 8 5743 14 6.04 0.15 PP-AO-A51 311 4 5664 19 7.35 0.16PP-AO-B51 338 12 5737 80 5.95 0.13Docket No. 2919-3.01 47Table 5. Stress and Strain Performance of Tested Formulations Stress at 1% Strain Stress at 3% Strain Stress at 5% Strain Formulation _ _ (psi _ (PS ) _Average STDEV Average STDEV Average STDEV Control PP 3113 22 5108 29 5717 28 PP-AO-A11 2894 60 4926 42 5585 32 PP-AO-B11 2960 73 5020 72 5646 67 PP-AO-A13 2954 50 5056 25 5721 15 PP-AO-B13 2957 119 4975 51 5646 20 PP-AO-A21 2911 37 4913 36 5576 41 PP-AO-B21 2889 57 4920 52 5577 33 PP-AO-A23 2968 45 5069 45 5716 43 PP-AO-B23 2749 45 4839 17 5535 27 PP-AO-A31 2968 105 5003 110 5652 85 PP-AO-B31 3064 29 5123 32 5720 29 PP-AO-B32 3034 62 5083 56 5691 36 PP-AO-A41 2873 29 4861 46 5551 52 PP-AO-B41 3072 95 5121 80 5696 53 PP-AO-B42 3015 45 5066 23 5679 11 PP-AO-A51 2808 26 4752 21 5457 12 PP-AO-B51 3042 89 5088 102 5682 90Docket No. 2919-3.01 48Table 6. Change in Mechanical Properties of Tested Formulations Formulation A Modulus (%) A Yield Stress (%) A Yield Strain (%) Control PP 0 0 0PP-AO-A11 -9.632 -1.7 4.54PP-AO-B11 -8.22 -1.57 -3.29PP-AO-A13 -7.93 0.48 4.38PP-AO-B13 -6.23 -0.46 6.57PP-AO-A21 -7.93 -1.57 8.76PP-AO-B21 -8.78 -2.32 2.5PP-AO-A23 -7.93 -0.31 -2.35PP-AO-B23 -13.88 -2.68 4.85PP-AO-A31 -7.08 -0.77 2.66PP-AO-B31 -2.55 -0.62 -6.73PP-AO-B32 -3.4 -1.02 -5.16PP-AO-A41 -10.2 -1.53 12.99PP-AO-B41 -1.98 -1.2 -8.29PP-AO-B42 -5.1 -1.19 -5.48PP-AO-A51 -11.9 -2.55 15.02PP-AO-B51 -4.25 -1.29 -6.89

[0161] As can be seen in Table 4 and Table 6 above, each of the tested formulations generally decreased the modulus of the material compared to the control polypropylene. Accordingly, adding the above formulations resulted in a less rigid (i.e., more flexible) material compared to the control polypropylene. As can be seen in Table 4, Table 5, and Table 6 above, the tested formulations generally had little to no effect on the yield stress of the material compared to the control polypropylene. Further, the tested formulations generally had little to no effect on the yield strain of the material compared to the control polypropylene. Accordingly, materials having the above antioxidant blends may have similar mechanical strengths compared to materials with no antioxidant blends.Docket No. 2919-3.01 49

[0162] Although the present disclosure has been described with reference to the embodiments illustrated in the attached drawing figures, it is noted that equivalents may be employed and substitutions made herein without departing from the scope of the present disclosure as recited in the claims.

[0163] Having thus described various embodiments of the present disclosure, what is claimed as new and desired to be protected by Letters Patent includes the following:Docket No. 2919-3.01 50

Claims

CLAIMS:

1. A polymeric material comprising:a base material comprising a polymer; andan antioxidant blend dispersed throughout the base material and configured to reduce degradation of the polymer,wherein the antioxidant blend comprises:a lactone-based antioxidant for reacting with carbon-centered free radicals in the polymer;a phenolic antioxidant for reacting with oxygen-centered free radicals in the polymer; anda phosphite antioxidant for reacting with unstable compounds in the polymer.

2. The polymeric material of claim 1, wherein the lactone-based antioxidant is according to formula (I):(I)Docket No. 2919-3.01 51wherein Ri, R2, and R3 are each independently chosen from a group consisting of a hydrocarbon, an alkyl, an aryl, an oligomer, and an additional polymer.

3. The polymeric material of claim 2, wherein the lactone-based antioxidant is according to formula (II):(H)4. The polymeric material of claim 1, wherein the phenolic antioxidant is according to formula (III):Docket No. 2919-3.01 525. The polymeric material of claim 1, wherein the phosphite antioxidant is a compound according to formula (IV) or formula (V):(IV)Docket No. 2919-3.01 536. The polymeric material of claim 1,wherein the base material constitutes at least 90% of the polymeric material, wherein the antioxidant blend constitutes up to 7% of the polymeric material.

7. The polymeric material of claim 6,wherein the phenolic antioxidant constitutes 30% to 75% of the antioxidant blend, wherein the phosphite antioxidant constitutes 25% to 50% of the antioxidant blend, wherein the lactone-based antioxidant constitutes up to 35% of the antioxidant blend.

8. The polymeric material of claim 1, wherein the polymeric material is utilized in conditions having a temperature of up to 300°F.Docket No. 2919-3.01 549. An antioxidant blend for use with a polymer material, the antioxidant blend comprising:a lactone-based antioxidant for reacting with carbon-centered free radicals in the polymer material;a phenolic antioxidant for reacting with oxygen-centered free radicals in the polymer material; anda phosphite antioxidant for reacting with unstable compounds in the polymer material.

10. The antioxidant blend of claim 9, wherein the lactone-based antioxidant is a compound according to formula (I):(I)wherein Ri, R2, and R3 are each independently chosen from a group consisting of a hydrocarbon, an alkyl, an aryl, an oligomer, and an additional polymer.

11. The antioxidant blend of claim 10, wherein the lactone-based antioxidant is according to formula (II):Docket No. 2919-3.01 55(H)12. The antioxidant blend of claim 9, wherein the phenolic antioxidant is according to formula (III):(HI)Docket No. 2919-3.01 5613. The antioxidant blend of claim 9, wherein the phosphite antioxidant is according to formula (IV) or formula (V):(IV)14. The antioxidant blend of claim 9,wherein the phenolic antioxidant constitutes 30% to 65% of the antioxidant blend, wherein the phosphite antioxidant constitutes 25% to 50% of the antioxidant blend,Docket No. 2919-3.01 57wherein the lactone-based antioxidant constitutes up to 35% of the antioxidant blend.

15. The antioxidant blend of claim 14,wherein the phenolic antioxidant constitutes 42.5% to 47.5% of the antioxidant blend,wherein the phosphite antioxidant constitutes 42.5% to 47.5% of the antioxidant blend,wherein the lactone-based antioxidant constitutes 5% to 15% of the antioxidant blend.Docket No. 2919-3.01 5816. A conveyor belt for use in a processing system, the conveyor belt comprising:a belt configured to move one or more objects through the processing system, wherein the belt is manufactured from a polymeric material, the polymeric material comprising:a base material comprising a polymer; andan antioxidant blend dispersed throughout the base material and configured to reduce degradation of the polymer,wherein the antioxidant blend comprises:a lactone-based antioxidant for reacting with carbon-centered free radicals in the polymer;a phenolic antioxidant for reacting with oxygen-centered free radicals in the polymer; anda phosphite antioxidant for reacting with unstable compounds in the polymer.

17. The conveyor belt of claim 16, wherein the lactone-based antioxidant is a compound according to formula (I):(I)Docket No. 2919-3.01 59owherein Ri, R2, and R3 are each independently chosen from a group consisting of a hydrocarbon, an alkyl, an aryl, an oligomer, and an additional polymer.

18. The conveyor belt of claim 17, wherein the lactone-based antioxidant is according to formula (II):(H)19. The conveyor belt of claim 16, wherein the phenolic antioxidant is according to formula (III):Docket No. 2919-3.01 60(III)20. The conveyor belt of claim 16, wherein the phosphite antioxidant is according to formula (IV) or formula (V):(IV)Docket No. 2919-3.01 61(V)Docket No. 2919-3.01 62

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