Foamed antioxidant masterbatch and method of making the same

Abstract

In general, a foamed antioxidant masterbatch is disclosed. The foamed antioxidant masterbatch comprises an olefin polymer and one or more organic phosphite antioxidants. The foamed antioxidant masterbatch comprises a cell structure comprising one or more cells. The one or more organic phosphite antioxidants is provided in the one or more cells. The present disclosure is also directed to a method of making a foamed antioxidant masterbatch using a foaming agent and a method of making a polymer composition from the foamed antioxidant masterbatch and a second polymer.

Description

FOAMED ANTIOXIDANT MASTERBATCH AND METHOD OF MAKING THE SAME Cross-Reference to Related Application

[0001] The present application claims filing benefit of US Provisional Patent Application No.63 / 610,516 having a filing date of December 15, 2023, which is incorporated herein by reference in its entirety. Background

[0002] Polymers, particularly olefin polymers, are known to be utilized for a number of applications due to their versatility. Depending on the particular application, various stabilizers may also be utilized and blended with the polymer to provide the resulting polymer composition with desired properties. For example, generally, antioxidants may be provided to help prevent or minimize oxidation which can negatively impact and degrade the polymer resulting in a loss of physical properties. However, when utilizing certain stabilizers, in particular certain antioxidants, they may exhibit poor solubility resulting in blooming on the surface of a resulting polymer composition and / or article. Accordingly, such polymer composition may have a less than desire storage stability.

[0003] As such, a need currently exists for providing an improved polyolefin composition including an antioxidant with a desired storage stability. Summary of the Disclosure

[0004] In accordance with one embodiment of the present disclosure, a foamed antioxidant masterbatch is disclosed. The foamed antioxidant masterbatch comprises an olefin polymer and one or more organic phosphite antioxidants. The foamed antioxidant masterbatch comprises a cell structure comprising one or more cells. The one or more organic phosphite antioxidants is provided in the one or more cells.

[0005] In accordance with another embodiment of the present disclosure, a method of making a foamed antioxidant masterbatch is disclosed. The method comprises: melt blending an olefin polymer, one or more organic phosphite antioxidants, and a foaming agent. The foaming agent forms the one or more cellsin the olefin polymer. The foamed antioxidant masterbatch comprises the olefin polymer and the one or more organic phosphite antioxidants. The foamed antioxidant masterbatch comprises a cell structure comprising the one or more cells. The one or more organic phosphite antioxidants is provided in the one or more cells.

[0006] In accordance with another embodiment of the present disclosure, a method of making a polymer composition is disclosed. The method comprises: melt blending a foamed antioxidant masterbatch with a second polymer. The foamed antioxidant masterbatch comprises an olefin polymer and one or more organic phosphite antioxidants. The foamed antioxidant masterbatch comprises a cell structure comprising one or more cells. The one or more organic phosphite antioxidants is provided in the one or more cells. Brief Description of the Drawings

[0007] Figure 1 illustrates the organic phosphite antioxidant hydrolysis stability of Sample No.1 of Example 1.

[0008] Figure 2 compares the organic phosphite antioxidant hydrolysis stability of the foamed and unfoamed organic phosphite antioxidant masterbatch of Example 2.

[0009] Figure 3 compares the organic phosphite antioxidant hydrolysis stability of the foamed organic phosphite antioxidant masterbatch of Example 2 based on the use of triisopropanolamine.

[0010] Figure 4 compares the organic phosphite antioxidant hydrolysis stability based on the amount of foaming agent and the organic phosphite antioxidant in the foamed organic phosphite antioxidant masterbatch. Definitions

[0011] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

[0012] “Alkyl” refers to straight chain, branched chain, or cyclic monovalent saturated aliphatic hydrocarbyl groups and “Cq-Cralkyl” refers to alkyl groups having from q to r carbon atoms. This term includes, by way of example, straightchain, branched chain, or cyclic hydrocarbyl groups, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosanyl, henicosanyl, docosanyl, tricosanyl, tetracosanyl, pentacosanyl, hexacosanyl, heptacosanyl, octacosanyl, and the like. Alkyl includes a substituted alkyl or an unsubstituted alkyl. For example, the alkyl may be substituted (e.g., having from 1 to 5 and, in some embodiments, 1 to 3 or 1 to 2 substituents). Alternatively, the alkyl may be unsubstituted.

[0013] “Alkenyl” refers to a straight chain or branched chain monovalent aliphatic hydrocarbyl group having at least 1 site of vinyl unsaturation (>C=C<). For example, “C3-Ctalkenyl” refers to alkenyl groups having from s to t carbon atoms. This term includes, by way of example, straight chain or branched chain hydrocarbyl groups, such as ethenyl, propenyl, 1,3-butadienyl, and the like. Alkenyl includes a substituted alkenyl or an unsubstituted alkenyl. For example, the alkenyl may be substituted (e.g., having from 1 to 5 and, in some embodiments, 1 to 3 or 1 to 2 substituents). Alternatively, the alkenyl may be unsubstituted.

[0014] “Alkynyl” refers to a straight chain or branched chain monovalent aliphatic hydrocarbyl group having at least one carbon triple bond. The term “alkynyl” is also meant to include those hydrocarbyl groups having one triple bond and one double bond. For example, “Cu-Cv alkynyl” refers to alkynyl groups having from u to v carbon atoms. This term includes, by way of example, straight chain or branched chain hydrocarbyl groups, such as ethynyl, propynyl, and the like. Alkynyl includes a substituted alkynyl or an unsubstituted alkynyl. For example, the alkynyl may be substituted (e.g., having from 1 to 5 and, in some embodiments, 1 to 3 or 1 to 2 substituents). Alternatively, the alkynyl may be unsubstituted.

[0015] “Aryl” refers to an aromatic hydrocarbyl group. For example, “Cw-Cx aryl” refers to aryl groups having from w to x carbon atoms. This term includes, by way of example, linear and branched hydrocarbyl groups, such as phenyl, naphthyl, indenyl, azulenyl, fluorenyl, anthracenyl, phenanthrenyl, tetrahydronaphthyl, indanyl, phenanthridinyl and the like. Aryl includes a substituted aryl or an unsubstituted aryl. For example, the aryl may be substituted(e.g., having from 1 to 5 and, in some embodiments, 1 to 3 or 1 to 2 substituents). Alternatively, the aryl may be unsubstituted.

[0016] It is understood that the above definitions are not intended to include impermissible substitution patterns (e.g., methyl substituted with 5 fluoro groups). Such impermissible substitution patterns are well known to a person skilled in the art. Detailed Description

[0017] It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present disclosure.

[0018] Generally speaking, the present disclosure is directed to a foamed antioxidant masterbatch as well as a method of making a foamed antioxidant masterbatch. The foamed antioxidant masterbatch includes an olefin polymer and one or more organic phosphite antioxidants and can be formed using a foaming agent as defined herein.

[0019] In accordance with the present disclosure and the method of making the foamed antioxidant masterbatch, the present inventors have discovered that the foaming agent may be better dispersed in the olefin polymer thereby resulting in a relatively uniform foam structure. Accordingly, the present inventors have also discovered that the one or more organic phosphite antioxidants, along with any other additives, may also be well dispersed in the olefin polymer.

[0020] Furthermore, the foamed antioxidant masterbatch as disclosed herein may provide for an increased concentration or loading of the one or more organic phosphite antioxidants. In addition, even with such increased concentration or loading, the foamed antioxidant masterbatch may exhibit enhanced storage stability / shelf life, in particular at varying conditions. For instance, such storage stability may be exhibited at ambient conditions of 25°C, 50% humidity or even at conditions with a relatively elevated temperature and / or humidity. Due to such storage stability, the foamed antioxidant masterbatch also demonstrates improved handleability for use in downstream processes for the formation of polymer composition and corresponding polymeric articles.

[0021] In addition, without intending to be limited, such enhanced storage stability / shelf life may be attributed to the enhanced hydrolysis stability of the organic phosphite antioxidant and / or reduced blooming of the organic phosphite antioxidant.

[0022] In this regard, the foamed antioxidant masterbatch may exhibit enhanced hydrolysis stability of the organic phosphite antioxidant. In general, without intending to be limited, hydrolysis may lead to a decrease in effectiveness of the organic phosphite antioxidant. In this regard, after a certain period of time, less than 10 wt.%, such as less than 9 wt.%, such as less than 8 wt.%, such as less than 7 wt.%, such as less than 6 wt.%, such as less than 5 wt.%, such as less than 4 wt.%, such as less than 3 wt.%, such as less than 2 wt.%, such as less than 1 wt.% of the original amount of the one or more organic phosphite antioxidant may be hydrolyzed. Related, 0 wt.% or more, such as 0.01 wt.% or more, such as 0.05 wt.% or more, such as 0.1 wt.% or more, such as 0.2 wt.% or more, such as 0.3 wt.% or more, such as 0.5 wt.% or more, such as 0.8 wt.% or more, such as 1 wt.% or more, such as 1.2 wt.% or more, such as 1.5 wt.% or more, such as 1.8 wt.% or more, such as 2 wt.% or more, such as 2.2 wt.% or more, such as 2.5 wt.% or more, such as 2.7 wt.% or more, such as 3 wt.% or more, such as 3.3 wt.% or more, such as 3.5 wt.% or more, such as 3.8 wt.% or more, such as 4 wt.% or more, such as 4.3 wt.% or more, such as 4.5 wt.% or more, such as 4.7 wt.% or more, such as 5 wt.% or more of the original amount of the one or more organic phosphite antioxidant may be hydrolyzed within a certain time period. Such aforementioned time period may be after 4 days, such as after 5 days, such as after 7 days, such as after 10 days, such as after 14 days, such as after 18 days, such as after 20 days, such as after 24 days, such as after 28 days, such as after 32 days, such as after 36 days, such as after 40 days, such as after 60 days, such as after 90 days, such as after 120 days from formation of the foamed antioxidant masterbatch. In one embodiment, such hydrolysis may be determined at 25°C and 50% humidity. In another embodiment, such hydrolysis may be determined at 50°C and 80% humidity.

[0023] Further, the foamed antioxidant masterbatch may exhibit reduced blooming of the organic phosphite antioxidant in the foamed antioxidant masterbatch. Blooming may generally be exudation of the organic phosphiteantioxidant, which may cause a haze, film, or powder on the surface of the polymer. In general, without intending to be limited, blooming may lead to the loss of pellet / masterbatch flowability. In this regard, minimizing such blooming may lead to enhanced storage stability / shelf life as well as enhanced handleability.

[0024] Olefin Polymer

[0025] As indicated above, the foamed antioxidant masterbatch includes an olefin polymer. The olefin polymer may serve as a carrier for the one or more organic phosphite antioxidants.

[0026] The olefin polymer may be a homopolymer, a copolymer, or a mixture thereof. In one embodiment, the olefin polymer may be an olefin homopolymer. In another embodiment, the olefin polymer may be an olefin copolymer.

[0027] The olefin polymer may be an ethylene polymer, a propylene polymer, or a mixture thereof. In one embodiment, the olefin polymer may be an ethylene polymer. For instance, the ethylene polymer may be an ethylene homopolymer in one embodiment. Further, the ethylene polymer may be an ethylene copolymer in one embodiment. In addition, in one embodiment, the olefin polymer may be a propylene polymer. For instance, the propylene polymer may be a propylene homopolymer in one embodiment. Further, the propylene polymer may be a propylene copolymer in one embodiment.

[0028] As indicated, the olefin polymer may be an olefin homopolymer. In this regard, the olefin homopolymer may be of a C2-C10 alpha-olefin, such as ethylene, propylene, 1-butene, 1-hexene, 1-octene, etc. Accordingly, the olefin homopolymer may be polyethylene, polypropylene, or a mixture thereof. In one embodiment, the olefin polymer, such as the olefin homopolymer, may be polyethylene. In another embodiment, the olefin polymer, such as the olefin homopolymer, may be polypropylene.

[0029] As indicated, the olefin polymer may be an olefin copolymer. For instance, the olefin copolymer may be an ethylene copolymer, a propylene copolymer, or a mixture thereof. For an ethylene copolymer, the copolymer may be formed from ethylene and one or more C3-C10 alpha-olefins, such as propylene, 1-butene, 1-hexene, 1-octene, etc. For a propylene copolymer, the copolymer may be formed from propylene and one or more of C2, C4-C10alpha-olefins, suchas ethylene, 1-butene, 1-hexene, 1-octene, etc. Regarding the copolymers, the ethylene or propylene may constitute majority of the monomer units of the respective copolymer while the remaining comonomers may constitute a minority, either individually or collectively, of the monomer units of the respective copolymer.

[0030] Regarding the ethylene copolymer, the ethylene copolymer may be an ethylene / propylene copolymer in one embodiment. In one embodiment, the ethylene copolymer may be formed from ethylene and one or more of 1-butene, 1- hexene, and 1-octene. In a further embodiment, the ethylene copolymer may be formed from ethylene and two or more of 1-butene, 1-hexene, and 1-octene. In an even further embodiment, the ethylene copolymer may be formed from ethylene and all three of 1-butene, 1-hexene, and 1-octene.

[0031] Regarding the propylene copolymer, the propylene copolymer may be a propylene / ethylene copolymer in one embodiment. In one embodiment, the propylene copolymer may be formed from propylene and one or more of 1-butene, 1-hexene, and 1-octene. In a further embodiment, the propylene copolymer may be formed from propylene and two or more of 1-butene, 1-hexene, and 1-octene. In an even further embodiment, the propylene copolymer may be formed from propylene and all three of 1-butene, 1-hexene, and 1-octene.

[0032] The copolymers may be synthesized using means generally known in the art. For instance, they may be synthesized using various catalyst chemistries depending on the desired properties of the polymer. As examples, they may be metallocene-catalyzed, Ziegler Natta catalyzed, etc.

[0033] As indicated herein, the olefin polymer may be an ethylene polymer. In this regard, the ethylene polymer may be a linear low-density polyethylene, a very low-density polyethylene, a low-density polyethylene, a medium-density polyethylene, a high-density polyethylene, or a mixture thereof. For instance, the ethylene polymer may comprise a linear low-density polyethylene, a very low- density polyethylene, a low-density polyethylene, or a mixture thereof.

[0034] In one embodiment, the ethylene polymer may be a linear low- density polyethylene. Without intending to be limited, the linear low-density polyethylene may have a density of from 0.91 g / cm3to 0.94 g / cm3. In another embodiment, the ethylene polymer may be a low-density polyethylene. Without intending to be limited, the low-density polyethylene may have a density of from0.91 g / cm3to 0.94 g / cm3. In one embodiment, the ethylene polymer may be a medium-density polyethylene. Without intending to be limited, the medium-density polyethylene may have a density of from 0.926 g / cm3to 0.94 g / cm3. In a further embodiment, the ethylene polymer may be a high-density polyethylene. Without intending to be limited, the high-density polyethylene may have a density of from 0.941 g / cm3to 0.965 g / cm3. In an even further embodiment, the ethylene polymer may be a very low-density polyethylene. Without intending to be limited, the very low-density polyethylene may have a density of from 0.885 g / cm3to 0.915 g / cm3.

[0035] In addition, the olefin polymer may be recycled and / or virgin. In this regard, the olefin polymer may be a recycled olefin polymer, a virgin olefin polymer, or a mixture thereof. In one embodiment, the olefin polymer may be a recycled olefin polymer, such as a recycled ethylene polymer and / or a recycled propylene polymer. In another embodiment, the olefin polymer may be a virgin olefin polymer, such as a virgin ethylene polymer and / or a virgin propylene polymer.

[0036] Further, in one embodiment, the ethylene polymer may be a virgin linear low-density polyethylene. In another embodiment, the ethylene polymer may be a recycled linear low-density polyethylene. In a further embodiment, the ethylene polymer may be a mixture of a virgin linear low-density polyethylene and a recycled linear low-density polyethylene.

[0037] In one embodiment, the ethylene polymer may be a virgin low- density polyethylene. In another embodiment, the ethylene polymer may be a recycled low-density polyethylene. In a further embodiment, the ethylene polymer may be a mixture of a virgin low-density polyethylene and a recycled low-density polyethylene.

[0038] In one embodiment, the ethylene polymer may be a virgin high- density polyethylene. In another embodiment, the ethylene polymer may be a recycled high-density polyethylene. In a further embodiment, the ethylene polymer may be a mixture of a virgin high-density polyethylene and a recycled high-density polyethylene.

[0039] The olefin polymer may have a particular melt flow rate. For instance, the melt flow rate may range from 0.1 g / 10 min to 50 g / 10 min (190° C., 2.16 k loading). In this regard, the melt flow rate may be 0.1 g / 10 min or more,such as 0.2 g / 10 min or more, such as 0.4 g / 10 min or more, such as 0.6 g / 10 min or more, such as 0.8 g / 10 min or more, such as 1 g / 10 min or more, such as 1.2 g / 10 min or more, such as 1.4 g / 10 min or more, such as 1.6 g / 10 min or more, such as 1.8 g / 10 min or more, such as 2 g / 10 min or more, such as 2.2 g / 10 min or more, such as 2.4 g / 10 min or more, such as 2.6 g / 10 min or more, such as 2.8 g / 10 min or more, such as 3 g / 10 min or more, such as 3.2 g / 10 min or more, such as 3.4 g / 10 min or more, such as 3.6 g / 10 min or more, such as 3.8 g / 10 min or more, such as 4 g / 10 min or more, such as 4.5 g / 10 min or more, such as 5 g / 10 min or more, such as 6 g / 10 min or more, such as 7 g / 10 min or more, such as 8 g / 10 min or more, such as 9 g / 10 min or more, such as 10 g / 10 min or more. The melt flow rate may be 50 g / 10 min or less, such as 45 g / 10 min or less, such as 40 g / 10 min or less, such as 35 g / 10 min or less, such as 30 g / 10 min or less, such as 25 g / 10 min or less, such as 20 g / 10 min or less, such as 18 g / 10 min or less, such as 16 g / 10 min or less, such as 14 g / 10 min or less, such as 12 g / 10 min or less, such as 10 g / 10 min or less, such as 9 g / 10 min or less, such as 8 g / 10 min or less, such as 7 g / 10 min or less, such as 6 g / 10 min or less, such as 5 g / 10 min or less, such as 4.5 g / 10 min or less, such as 4 g / 10 min or less, such as 3.5 g / 10 min or less, such as 3 g / 10 min or less, such as 2.5 g / 10 min or less, such as 2 g / 10 min or less, such as 1.5 g / 10 min or less, such as 1 g / 10 min or less.

[0040] The olefin polymer may include any combination of olefin polymers. For instance, the olefin polymer may include two or more olefin polymers, such as those defined herein, in one embodiment. In another embodiment, the olefin polymer may only include one olefin polymer, such as those defined herein. In this regard, in one embodiment, the foamed antioxidant masterbatch may only include one olefin polymer.

[0041] The olefin polymer may be present in the foamed antioxidant masterbatch in a particular amount. For instance, the olefin polymer may be present in the foamed antioxidant masterbatch in an amount of about 30 wt.% or more, such as about 35 wt.% or more, such as about 40 wt.% or more, such as about 45 wt.% or more, such as about 50 wt.% or more, such as about 55 wt.% or more, such as about 60 wt.% or more, such as about 65 wt.% or more, such as about 70 wt.% or more, such as about 75 wt.% or more, such as about 80 wt.% or more, such as about 85 wt.% or more, such as about 90 wt.% or more based onthe weight of the foamed antioxidant masterbatch. The olefin polymer may be present in the foamed antioxidant masterbatch in an amount of about 95 wt.% or less, such as about 90 wt.% or less, such as about 85 wt.% or less, such as about 80 wt.% or less, such as about 75 wt.% or less, such as about 70 wt.% or less, such as about 65 wt.% or less, such as about 60 wt.% or less, such as about 55 wt.% or less, such as about 50 wt.% or less, such as about 45 wt.% or less, such as about 40 wt.% or less based on the weight of the foamed antioxidant masterbatch.

[0042] The olefin polymer may be present in the foamed antioxidant masterbatch in an amount of about 30 wt.% or more, such as about 35 wt.% or more, such as about 40 wt.% or more, such as about 45 wt.% or more, such as about 50 wt.% or more, such as about 55 wt.% or more, such as about 60 wt.% or more, such as about 65 wt.% or more, such as about 70 wt.% or more, such as about 75 wt.% or more, such as about 80 wt.% or more, such as about 85 wt.% or more, such as about 90 wt.% or more based on the weight of the olefin polymer and the one or more organic phosphite antioxidants. The olefin polymer may be present in the foamed antioxidant masterbatch in an amount of about 95 wt.% or less, such as about 90 wt.% or less, such as about 85 wt.% or less, such as about 80 wt.% or less, such as about 75 wt.% or less, such as about 70 wt.% or less, such as about 65 wt.% or less, such as about 60 wt.% or less, such as about 55 wt.% or less, such as about 50 wt.% or less, such as about 45 wt.% or less, such as about 40 wt.% or less based on the weight of the olefin polymer and the one or more organic phosphite antioxidants.

[0043] Organic Phosphite Antioxidants

[0044] As indicated above, the foamed antioxidant masterbatch also includes one or more organic phosphite antioxidants. In one embodiment, the foamed antioxidant masterbatch may include only one organic phosphite antioxidant. In another embodiment, the foamed antioxidant masterbatch may include at least two organic phosphite antioxidants. In such embodiments, at least one organic phosphite antioxidant may be a primary antioxidant. For instance, such primary antioxidant may be present in an amount of more than 50 wt.%, such as 55 wt.% or more, such as 60 wt.% or more, such as 65 wt.% or more, such as 70 wt.% or more, such as 75 wt.% or more, such as 80 wt.% or more, such as 85wt.% or more, such as 90 wt.% or more, such as 95 wt.% or more, such as 97 wt.% or more, such as 99 wt.% or more, such as 99.5 wt.% or more, such as 99.9 wt.% or more based on the total weight of the organic phosphite antioxidants.

[0045] The organic phosphite antioxidant may include, but is not limited to, a triaryl phosphite, a trialkyl phosphite, an alkylphenol-free polymeric polyphosphite, or a mixture thereof. In one embodiment, the organic phosphite antioxidant comprises a triaryl phosphite. In another embodiment, the organic phosphite antioxidant comprises a trialkyl phosphite. In a further embodiment, the organic phosphite comprises an alkylphenol-free polymeric polyphosphite.

[0046] The organic phosphite antioxidant may include, but is not limited to, bis(2,4,di-t-butylphenyl)pentaerythritol diphosphite (ULTRANOX™ 626 – CAS 26741-53-7); 2,4,6-tri-tert-butylphenyl-2-butyl-2-ethyl-1,3-propanediol phosphite (ULTRANOX™ 641 – CAS 161717-32-4); tris(2,4-di-t-butylphenyl)phosphite(ALKANOX™ 240 – CAS 31570-04-4); tetrakis (2,4-di-t- -biphenylene diphosphonite (ALKANOX™ 24-44 – CAS 38613-77-3); tris(4-n- nonylphenyl)phosphite (WESTON™ TNPP – CAS 26523-78-4); distearylpentaerythritol diphosphite (WESTON™ 618 – CAS 3806-34-6); bis(2,4- dicumylphenyl) pentaerythritol diphosphite (DOVERPHOS™ 9228 – CAS 154862- 43-8, available from Dover Chemical Corporation); phosphorous acid, mixed 2,4- bis(1,1-dimethylpropyl)phenyl and 4-(1,1-dimethylpropyl)phenyl triesters (WESTON™ 705 – CAS 939402-02-5); tris(dipropyleneglycol) phosphite, C18H3909P (WESTON™ 430 – CAS 36788-39-3); poly(dipropylene glycol) phenyl phosphite (WESTON™ DHOP – CAS 80584-86-7); diphenyl isodecyl phosphite, C22H31O3P (WESTON™ DPDP – CAS 26544-23-0); phenyl diisodecyl phosphite (WESTON™ PDDP – CAS 25550-98-5); heptakis (dipropyleneglycol) triphosphite (WESTON™ PTP – CAS 13474-96-9); bis(2,6-di-tert-butyl-4- methylphenyl)pentaerythritol diphosphite (PEP 36 – CAS 80693-00-1); tris(2-t- butylphenyl)phosphite (CAS 31502-36-0); trisphenyl phosphite; and / or compatible mixtures of two or more thereof.

[0047] In one particular embodiment, the one or more organic phosphite antioxidants may include at least phosphorous acid, mixed 2,4-bis(1,1- dimethylpropyl)phenyl and 4-(1,1-dimethylpropyl)phenyl triesters (WESTON™ 705 – CAS 939402-02-5). In this regard, the organic phosphite antioxidant mayinclude, but is not limited to, tris-4-tert-butyl phenyl phosphite, tris 2,4-di-tert-butyl phenyl phosphite, bis(4-tert-butylphenyl)-2,4-di-tert-butylphenyl phosphite, bis(2,4- di-tert-butylphenyl)-4-tert-butylphenyl phosphite, tris 4-tert-pentyl phenyl phosphite, tris 2,4-di-tert-pentyl phenyl phosphite, bis(4-tert-pentylphenyl)-2,4-di-tert- pentylphenyl phosphite, bis(2,4-di-tert-pentylphenyl)-4-tert-pentylphenyl phosphite, the like, as well as mixtures thereof.

[0048] In this regard, in one embodiment, the organic phosphite antioxidant may have the following structure (I):wherein, R4, R5, and R6 are each independently hydrogen, alkyl, alkenyl, alkynyl, or aryl provided that at least one of R4, R5, and R6is not hydrogen; and m, n, and o are each independently from 1 to 3.

[0049] As indicated above, R4, R5, and R6 are each independently hydrogen, alkyl, alkenyl, alkynyl, or aryl provided that at least one of R4, R5, and R6is not hydrogen. In this regard, at least one, such as at least two of R4, R5, and R6may be hydrogen provided that at least one of R4, R5, and R6 is not hydrogen. Accordingly, in one embodiment, at least one of R4, R5, and R6may be an alkyl. In another embodiment, at least one of R4, R5, and R6may be an alkenyl. In a further embodiment, at least one of R4, R5, and R6 may be an alkynyl. In another further embodiment, at least one of R4, R5, and R6 may be an aryl.

[0050] In particular, R4, R5, and R6may each independently be a C1-C20alkyl, a C2-C20 alkenyl, a C2-C20 alkynyl, or a C3-C12 aryl. In this regard, in one embodiment, at least one of R4, R5, and R6 may be a C1-C20 alkyl. In another embodiment, at least one of R4, R5, and R6may be a C2-C20alkenyl. In a furtherembodiment, at least one of R4, R5, and R6may be a C2-C20alkynyl. In another further embodiment, at least one of R4, R5, and R6 may be a C3-C12 aryl.

[0051] As indicated above, in one embodiment, at least one of, such as at least two of, such as all three of R4, R5, and R6may include an alkyl. In particular, it may include a C1-C20 alkyl. In this regard, the alkyl may be a C1-C20 alkyl, such as a C1-C16 alkyl, such as a C1-C12 alkyl, such as a C1-C10 alkyl, such as a C2-C8 alkyl, such as a C3-C6alkyl, such as a C4-C6alkyl. For instance, the alkyl may have 1 or more, such as 2 or more, such as 3 or more, such as 4 or more, such as 5 or more, such as 6 or more, such as 8 or more, such as 10 or more carbon atoms. The alkyl may have 20 or less, such as 18 or less, such as 16 or less carbon atoms, such as 14 or less, such as 12 or less, such as 10 or less, such as 8 or less, such as 6 or less carbon atoms. In addition, the alkyl may be a straight chain or a branched chain. In one embodiment, the alkyl is a straight chain. In another embodiment, the alkyl is a branched chain.

[0052] In one particular embodiment, at least one of R4, R5, and R6 may be tert-butyl or tert-pentyl. For instance, at least one of, such as at least two of, such as at least three of R4, R5, and R6may be tert-butyl. In another embodiment, at least one of, such as at least two of, such as at least three of R4, R5, and R6 may be tert-pentyl.

[0053] In one particular embodiment, at least one of R4, R5, and R6may be nonyl. For instance, at least one of, such as at least two of, such as at least three of R4, R5, and R6 may be nonyl. In another embodiment, at least one of, such as at least two of, such as at least three of R4, R5, and R6may be nonyl.

[0054] However, in one embodiment, the organic phosphite antioxidant may include a very low amount of certain alkyls. For example, such alkyls may be C8- C10, in particular C9alkyls. In this regard, in one embodiment, the alkyl may comprise less than 1,000 ppm, such as less than 500 ppm, such as less than 100 ppm, such as less than 50 ppm, such as less than 25 ppm, such as less than 10 ppm, such as less than 5 ppm, such as less than 1 ppm, such as 0 ppm of such alkyl.

[0055] As indicated above, in one embodiment, at least one of, such as at least two of, such as all three of R4, R5, and R6may include an alkenyl. In particular, it may include a C2-C20alkenyl. In this regard, the alkenyl may be a C2-C20alkenyl, such as a C2-C16alkenyl, such as a C2-C12alkenyl, such as a C2-C10alkenyl, such as a C2-C8 alkenyl, such as a C3-C6 alkenyl, such as a C4-C6 alkenyl. For instance, the alkenyl may have 2 or more, such as 3 or more, such as 4 or more, such as 5 or more, such as 6 or more, such as 8 or more, such as 10 or more, such as 12 or more, such as 14 or more, such as 16 or more carbon atoms. The alkenyl may have 20 or less, such as 18 or less, such as 16 or less carbon atoms, such as 14 or less, such as 12 or less, such as 10 or less, such as 8 or less, such as 6 or less carbon atoms. In addition, the alkenyl may be a straight chain or a branched chain. In one embodiment, the alkenyl is a straight chain. In another embodiment, the alkenyl is a branched chain.

[0056] As indicated above, in one embodiment, at least one of, such as at least two of, such as all three of R4, R5, and R6 may include an alkynyl. In particular, it may include a C2-C20alkynyl. In this regard, the alkynyl may be a C2- C20alkynyl, such as a C2-C16alkynyl, such as a C2-C12alkynyl, such as a C2-C10alkynyl, such as a C2-C8 alkynyl, such as a C3-C6 alkynyl, such as a C4-C6 alkynyl. For instance, the alkynyl may have 2 or more, such as 3 or more, such as 4 or more, such as 5 or more, such as 6 or more, such as 8 or more, such as 10 or more, such as 12 or more, such as 14 or more, such as 16 or more carbon atoms. The alkynyl may have 20 or less, such as 18 or less, such as 16 or less carbon atoms, such as 14 or less, such as 12 or less, such as 10 or less, such as 8 or less, such as 6 or less carbon atoms. In addition, the alkynyl may be a straight chain or a branched chain. In one embodiment, the alkynyl is a straight chain. In another embodiment, the alkynyl is a branched chain.

[0057] As indicated above, in one embodiment, at least one of, such as at least two of, such as all three of R4, R5, and R6 may include an aryl. In particular, it may include a C3-C12aryl. In this regard, the aryl may be a C3-C12aryl, such as a C4-C12aryl, such as a C6-C12aryl, such as a C6-C10aryl, such as a C6-C8aryl. For instance, the aryl may have 3 or more, such as 4 or more, such as 5 or more, such as 6 or more carbon atoms. The aryl may have 12 or less, such as 10 or less, such as 8 or less, such as 7 or less, such as 6 or less, such as 5 or less carbon atoms. In addition, in one embodiment, the aryl may be polycyclic. The polycyclic aryl may include fused, bridged, and spiro ring systems.

[0058] In one embodiment, R4, R5, and R6may all be the same. It should be understood that the substituent is the same substituent group and having the same length. For example, in one embodiment, R4, R5, and R6 may all be alkyl, such as a C5alkyl. In another embodiment, however, R4, R5, and R6may be different. For instance, in one embodiment, all three R4, R5, and R6 may be different. For instance, while they may have the same chemical formula, they may be isomers having a different structure or configuration. In another embodiment, at least two of R4, R5, and R6 may be the same while the other is different. By different, it should be understood that the substituent is a different substituent group. For example, one of the groups may be an alkyl while another may be an alkenyl. Alternatively, as another example, at least two of the groups may be an alkyl wherein each alkyl has a different chain length.

[0059] As indicated above, m, n, and o are each independently from 1 to 3. For instance, m may be from 1 to 3. In this regard, in one embodiment, m may be 1. In another embodiment, m may be 2. In a further embodiment, m may be 3. Similarly, n may be from 1 to 3. In this regard, in one embodiment, n may be 1. In another embodiment, n may be 2. In a further embodiment, n may be 3. Further, o may be from 1 to 3. In this regard, in one embodiment, o may be 1. In another embodiment, o may be 2. In a further embodiment, o may be 3.

[0060] Furthermore, in one embodiment, R4, R5, and R6may each independently be at the para position. For instance, when m, n, and o are each independently 1, R4, R5, and R6 may each independently be at the para position. In another embodiment, R4, R5, and R6may each independently be at the ortho position. For instance, in one embodiment, when m, n, and o are each independently 1, R4, R5, and R6 may each independently be at the ortho position. In another embodiment, when m, n, and o are each independently 2, R4, R5, and R6may each independently be at the para position and the ortho position.

[0061] In this regard, in one embodiment, m, n, and o may each be the same. For instance, in one embodiment, m, n, and o may be 1. Accordingly, in one embodiment, the organic phosphite antioxidant may have the following structure (II) wherein m, n, and o are each 1:

[0062] In another embodiment, m, n, and o may be 2. In this regard, R4, R5, and R6may each independently be at the ortho and para positions. The organic phosphite antioxidant may have the following structure (III) wherein m, n, and o are each 2:

[0063] In a further embodiment, m, n, and o may be 3. In this regard, R4, R5, and R6 may each independently be at the two ortho and para positions.

[0064] In addition, it should be understood that in one embodiment, all three of m, n, and o may be different. For instance, at least one of m, n, and o may be 1, while another of m, n, and o may be 2, while another of m, n, and o may be 3.

[0065] In a further embodiment, at least two of m, n, and o may be the same while the other is different. For instance, at least two of m, n, and o may be 1 while the third may be 2 or 3, such as 2 in one embodiment or 3 in another embodiment. In this regard, the organic phosphite antioxidant may have the following structure (IV) wherein n and o are 1 and m is 2:

[0066] Alternatively, at least two of m, n, and o may be 2 while the third may be 1 or 3, such as 1 in one embodiment or 3 in another embodiment. In this regard, the organic phosphite antioxidant may have the following structure (V) wherein m and n are 2 and o is 1:

[0067] In a further embodiment, at least two of m, n, and o may be 3 while the third may be 1 or 2, such as 1 in one embodiment or 2 in another embodiment.

[0068] In addition, it should be understood that any of the aforementioned organic phosphite antioxidants of structures (II), (III), (IV), or (V) may be utilized individually or in combination. For instance, at least one, such as at least two, such as at least three, such as at least all four of the aforementioned organic phosphite antioxidants of structures (II), (III), (IV), or (V) may be utilized.

[0069] Also, it should be understood that the foamed antioxidantmasterbatch may include a mixture of organic phosphite antioxidants. Forinstance, the foamed antioxidant masterbatch may include at least one, such as at least two, such as at least three, such as at least four organic phosphite antioxidants. As an example, each of the organic phosphite antioxidants may havea different number of substituent groups and / or different substituent groups as defined above.

[0070] Furthermore, when a mixture of organic phosphite antioxidants is utilized, they may be utilized within certain amounts. For instance, the weight ratio of the tris(monoalkylaryl)phosphites to the combination of bis(monoalkylaryl)dialkylaryl phosphites, bis(dialkylaryl)monoalkylaryl phosphites, and tris(dialkylaryl)phosphites may be within a certain range. Furthermore, the weight ratio of bis(monoalkylaryl)dialkylaryl phosphites to the combination of tris(monoalkylaryl)phosphites, bis(dialkylaryl)monoalkylaryl phosphites, and tris(dialkylaryl)phosphites may be within a certain range. In addition, the weight ratio of bis(dialkylaryl)monoalkylaryl phosphites to the combination of tris(monoalkylaryl)phosphites, bis(monoalkylaryl)dialkylaryl phosphites, and tris(dialkylaryl)phosphites may be within a certain range. Such weight ratios may be about 0.01 or more, such as about 0.033 or more, such as about 0.05 or more, such as about 0.1 or more, such as about 0.15 or more, such as about 0.2 or more, such as about 0.3 or more, such as about 0.33 or more, such as about 0.4 or more, such as about 0.5 or more, such as about 0.6 or more, such as about 0.66 or more. The weight ratios may be about 10 or less, such as about 8 or less, such as about 6 or less, such as about 4 or less, such as about 3 or less, such as about 2 or less, such as about 1.7 or less, such as about 1.5 or less, such as about 1.2 or less, such as about 1.1 or less, such as about 1 or less, such as about 0.9 or less, such as about 0.75 or less, such as about 0.66 or less, such as about 0.6 or less, such as about 0.55 or less, such as about 0.4 or less, such as about 0.2 or less, such as about 0.15 or less, such as about 0.11 or less, such as about 0.1 or less, such as about 0.05 or less, such as about 0.02 or less.

[0071] Also, the weight ratio of the tris(dialkylaryl)phosphites to the combination of bis(monoalkylaryl)dialkylaryl phosphites, bis(dialkylaryl)monoalkylaryl phosphites and tris(monoalkylaryl)phosphites may also be within a certain range. For instance, the weight ratio may be about 0.0001 or more, such as about 0.0002 or more, such as about 0.001 or more, such as about 0.01 or more, such as about 0.1 or more, such as about 0.2 or more, such as about 0.5 or more. The weight ratio may be about 5 or less, such as about 3 or less, such as about 2.5 or less, such as about 1.5 or less, such as about 1 or less,such as about 0.5 or less, such as about 0.1 or less, such as about 0.05 or less, such as about 0.02 or less, such as about 0.01 or less, such as about 0.005 or less.

[0072] The organic phosphite antioxidant may have a certain molecular weight. For instance, the molecular weight may be 400 g / mol or more, such as 450 g / mol or more, such as 500 g / mol or more, such as 550 g / mol or more, such as 600 g / mol or more, such as 650 g / mol or more. The molecular weight may be 1,000 g / mol or less, such as 900 g / mol or less, such as 800 g / mol or less, such as 750 g / mol or less, such as 700 g / mol or less, such as 650 g / mol or less, such as 600 g / mol or less.

[0073] The organic phosphite antioxidant may also have a certain phosphorus content. For instance, the phosphorus content may be 0.5 wt.% or more, such as 1 wt.% or more, such as 2 wt.% or more, such as 3 wt.% or more, such as 4 wt.% or more, such as 4.5 wt.% or more, such as 4.8 wt.% or more, such as 5 wt.% or more. The phosphorus content may be 10 wt.% or less, such as 8 wt.% or less, such as 6 wt.% or less, such as 5.5 wt.% or less, such as 5.3 wt.% or less.

[0074] The organic phosphite antioxidant may also have a certain kinematic viscosity. For instance, the kinematic viscosity may be 11,000 mm2 / s or less, such as 8,000 mm2 / s or less, such as 7,500 mm2 / s or less, such as 6,500 mm2 / s or less, such as 5,500 mm2 / s or less, such as 5,000 mm2 / s or less, such as 3,000 mm2 / s or less when measured at 30°C. The kinematic viscosity may be 1 mm2 / s or more, such as 50 mm2 / s or more, such as 100 mm2 / s or more, such as 500 mm2 / s or more, such as 1,000 mm2 / s or more, such as 2,000 mm2 / s or more, such as 3,000 mm2 / s or more, such as 4,000 mm2 / s or more when measured at 30°C. The viscosity may be determined using a glass capillary viscometer according to ASTM D445-19.

[0075] Furthermore, in one embodiment, the organic phosphite antioxidant may be a liquid at ambient conditions (i.e., at atmospheric pressure and a temperature of 25°C). In particular, the organic phosphite antioxidant may be a liquid at temperatures of less than 60°C, such as less than 50°C. For instance, while each component may not necessarily be a liquid individually, the organic phosphite antioxidant in its entirety may be a liquid. By providing such organicphosphite antioxidant as a liquid, it may be easily combined with the olefin polymer and other components to form the foamed antioxidant masterbatch.

[0076] The organic phosphite antioxidant may be present in the foamed antioxidant masterbatch in a particular amount. For instance, the organic phosphite antioxidant may be present in an amount of about 1 wt.% or more, such as about 3 wt.% or more, such as about 5 wt.% or more, such as about 8 wt.% or more, such as about 10 wt.% or more, such as about 12 wt.% or more, such as about 15 wt.% or more, such as about 18 wt.% or more, such as about 20 wt.% or more, such as about 22 wt.% or more, such as about 25 wt.% or more, such as about 28 wt.% or more, such as about 30 wt.% or more based on the weight of the foamed antioxidant masterbatch. The organic phosphite antioxidant may be present in an amount of about 50 wt.% or less, such as about 45 wt.% or less, such as about 40 wt.% or less, such as about 38 wt.% or less, such as about 35 wt.% or less, such as about 33 wt.% or less, such as about 30 wt.% or less, such as about 27 wt.% or less, such as about 25 wt.% or less, such as about 23 wt.% or less, such as about 20 wt.% or less, such as about 17 wt.% or less, such as about 15 wt.% or less, such as about 13 wt.% or less, such as about 10 wt.% or less, such as about 7 wt.% or less based on the weight of the foamed antioxidant masterbatch.

[0077] Further, it should be understood that the organic phosphite antioxidants may be present in the foamed antioxidant masterbatch in the percentages mentioned above. In addition or alternatively, each individual organic phosphite antioxidant may be present in the foamed antioxidant masterbatch in the percentages mentioned above.

[0078] Additives

[0079] In addition to the olefin polymer and the one or more organic phosphite antioxidants, the foamed antioxidant masterbatch may also include other additives. Such additives may be optional in one embodiment.

[0080] These additives may include, but are not limited to, a dispersant, a detergent, an antiwear agent, a further antioxidant, a light stabilizer, an ultraviolet absorber, a lubricant, an acid scavenger, a clarifying agent, a nucleating agent, a friction modifier, a corrosion inhibitor, a metal deactivator, a colorant, a flame retardant, an anti-static agent, an anti-block agent, a plasticizer, a filler, a Lewisbase, etc. as well as mixtures thereof. When utilized, they may be present in the foamed antioxidant masterbatch in an amount of about 0.01 wt.% or more, such as about 0.05 wt.% or more, such as about 0.1 wt.% or more, such as about 0.2 wt.% or more, such as about 0.3 wt.% or more, such as about 0.5 wt.% or more, such as about 0.8 wt.% or more, such as about 1 wt.% or more, such as about 1.5 wt.% or more, such as about 2 wt.% or more, such as about 2.5 wt.% or more, such as about 3 wt.% or more, such as about 3.5 wt.% or more, such as about 4 wt.% or more, such as about 4.5 wt.% or more, such as about 5 wt.% or more, such as about 6 wt.% or more, such as about 7 wt.% or more, such as about 8 wt.% or more, such as about 9 wt.% or more, such as about 10 wt.% or more, such as about 12 wt.% or more, such as about 15 wt.% or more, such as about 18 wt.% or more, such as about 20 wt.% or more based on the weight of the foamed antioxidant masterbatch. They may be utilized in an amount of about 40 wt.% or less, such as about 38 wt.% or less, such as about 35 wt.% or less, such as about 33 wt.% or less, such as about 30 wt.% or less, such as about 27 wt.% or less, such as about 25 wt.% or less, such as about 23 wt.% or less, such as about 20 wt.% or less, such as about 17 wt.% or less, such as about 15 wt.% or less, such as about 13 wt.% or less, such as about 10 wt.% or less, such as about 8 wt.% or less, such as about 6 wt.% or less, such as about 5 wt.% or less, such as about 4.5 wt.% or less, such as about 4 wt.% or less, such as about 3.5 wt.% or less, such as about 3 wt.% or less, such as about 2.5 wt.% or less, such as about 2 wt.% or less, such as about 1.5 wt.% or less, such as about 1 wt.% or less, such as about 0.8 wt.% or less, such as about 0.6 wt.% or less, such as about 0.5 wt.% or less, such as about 0.4 wt.% or less, such as about 0.3 wt.% or less, such as about 0.1 wt.% or less based on the weight of the foamed antioxidant masterbatch. In one embodiment, such aforementioned weight ratios may be based on the weight of the olefin polymer. In another embodiment, such aforementioned weight ratios may be based on the weight of the olefin polymer and the one or more organic phosphite antioxidants. In one particular embodiment, a respective additive may be present in the foamed antioxidant masterbatch in an amount of 0 wt.%.

[0081] Such aforementioned weight percentages may apply to any single additive as mentioned herein in one embodiment. In another embodiment, suchaforementioned weight percentages may apply to the combination of additives as mentioned herein.

[0082] In one embodiment, the foamed antioxidant masterbatch may comprise a Lewis base. Such Lewis bases are generally known in the art. For instance, such Lewis bases may generally be referred to as electron donors. In this regard, they may include compounds including OH-, F-, H2O, ROH, NH3, SO42-, H-, CO, and the like. In one embodiment, the Lewis base may include a compound including an OH-.

[0083] In one embodiment, the additive, such as the Lewis base, may comprise an alkanolamine. As generally understood in the art, alkanolamines contain both a hydroxyl group and an amino group on an alkane backbone. The alkanolamine may include, but is not limited to, a methanolamine, an ethanolamine, a propanolamine, or a mixture thereof. In one embodiment, the alkanolamine may be an ethanolamine, a propanolamine, or a mixture thereof. In a further embodiment, the alkanolamine may include a propanolamine.

[0084] Furthermore, the alkanolamine may be a monoalkanolamine, a dialkanolamine, a trialkanolamine, or a mixture thereof. In one embodiment, the alkanolamine may be a dialkanolamine, a trialkanolamine, or a mixture thereof. In a further embodiment, the alkanolamine may be a trialkanolamine. Examples of these alkanolamines may specifically include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, or a mixture thereof. In one particular embodiment, the alkanolamine may include triisopropanolamine. Other alkanolamines may include, but are not limited to, octyl-bis(2-ethanol)amine, nonyl-bis(2-ethanol)amine, decyl-bis(2-ethanolamine, undecyl-bis(2-ethanol)amine, dodecyl-bis(2-ethanol)amine, tridecyl-bis(2- ethanol)amine, tetradecyl-bis(2-ethanol)amine, pentadecyl-bis(2-ethanol)amine, hexadecyl-bis(2-ethanol)amine, heptadecyl-bis(2-ethanol)amine, octadecyl-bis(2- ethanol)amine, octyl-bis(2-propanol)amine, nonyl-bis(2-propanol)amine, decyl- bis(2-propanol)amine, undecyl-bis(2-propanol)amine, dodecyl-bis(2- propanol)amine, tridecyl-bis(2-propanol)amine, tetradecyl-bis(2-propanol)amine, pentadecyl-bis(2-propanol)amine, hexadecyl-bis(2-propanol)amine, heptadecyl- bis(2-propanol)amine, octadecyl-bis(2-propanol)amine, and mixtures thereof.

[0085] The foamed antioxidant masterbatch may comprise a further antioxidant. For instance, the further antioxidant may comprise one or more of a phenolic antioxidant, a sulfur-containing antioxidant, an aminic antioxidant, an inorganic phosphite antioxidant, or a mixture thereof.

[0086] In one embodiment, the further antioxidant may comprise a phenolic antioxidant. Such phenolic antioxidant may be a fully hindered phenolic antioxidant, a partially hindered phenolic antioxidant, a low-hindered phenolic antioxidant, a non-hindered phenolic antioxidant, or a mixture thereof. Such terms “fully hindered,” “partially hindered,” “low-hindered,” and “non-hindered” are generally understood by one skilled in the art.

[0087] In this context, by “fully hindered” it is preferably meant that the phenolic antioxidant comprises substituent hydrocarbyl groups on both positions ortho to the phenolic –OH group, each of those substituent groups being branched at the C1and / or C2position, preferably at the C1position, with respect to the aromatic ring.

[0088] The fully hindered phenolic antioxidant, if present, may comprise tetrakismethylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane (ANOX™ 20– CAS 6683-19- -di-t-butyl hydroxyphenyl)propionate](ANOX™ 70 – CAS 41484-35-9); octadecyl 3- -di-t-butyl- -hydroxyphenyl)propionate (ANOX™ PP18 / AO 1076 – CAS 2082-79-3); 1,3,5-tris(3,5-di-t-butyl-4- hydroxybenzyl) isocyanurate (ANOX™ IC14 – CAS 27676-62-6); 1,3,5-trimethyl- 2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene (ANOX™ 330 – CAS 1709-70-2); --(3,5-di-t-butyl-4-hydroxyphenyl)propionamide](LOWINOX™ HD98 – CAS 23128-74-7); 1,2-bis(3,5-di-t-butyl-4-hydroxyhydrocinnamoyl)hydrazine (LOWINOX™ MD24 – CAS 32687-78- --di-t-butylphenol] (ANOX™ 29 – CAS 35958-30-6); butylated hydroxytoluene (BHT – CAS 128-37-0); etc. and / or compatible mixtures of two or more thereof.

[0089] In this context, by “partially hindered” it is preferably meant that the phenolic antioxidant comprises at least one substituent hydrocarbyl group ortho to the phenolic –OH group, only one of the or each substituent group being branched at the C1and / or C2position, preferably at the C1position, with respect to the aromatic ring.

[0090] The partially hindered phenolic antioxidant, if present, may comprise 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H, 3H,5H)-trione (LOWINOX™ 1790 – CAS 40601-76-1); triethyleneglycol-bis- -(3-t-butyl-4-hydroxy-5-methylphenyl)propionate] (LOWINOX™ GP45 – CAS 36443-68- 2); the butylated reaction product of p-cresol and dicyclopentadiene (LOWINOX™CPL – CAS 68610-51- -methylenebis(6-t-butyl methylphenol) (LOWINOX™22M46 – CAS 119-47- - -(1,1-dimethylethyl)-4-hydroxyphenyl]butanoate] (CAS 32509-66-3); etc. and / or compatible mixtures of two or more thereof.

[0091] In this context, by “low hindered” it is preferably meant that the phenolic antioxidant comprises at least one substituent hydrocarbyl group ortho to the phenolic –OH group, none of those substituent groups being branched at the C1or C2position, preferably at the C1position, with respect to the aromatic ring.

[0092] In this context, by “non-hindered” it is preferably meant that the phenolic antioxidant comprises no substituent hydrocarbyl groups ortho to the phenolic –OH group.

[0093] The foamed antioxidant masterbatch may include a sulfur-containing antioxidant. The sulfur-containing antioxidant may comprise one or more thioether groups. Without intending to be limited, the sulfur-containing antioxidant may have a sulfur group with the formula –CH2–(S)x–CH2–, wherein x=1 or 2. In one embodiment, one or both of the –CH2– groups is directly bonded to an aromatic group. In another embodiment, neither of the –CH2– groups is directly bonded to an aromatic group. Particularly, in one embodiment, the sulfur-containing antioxidant may have the formula V–CH2–(S)x–CH2–W, wherein x=1 or 2 and wherein V and W respectively may be the same or different and may be or contain an aliphatic group.

[0094] The sulfur-containing antioxidant may include, but is not limited to, 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylanilino)-1,3,5-triazine (CAS 991- 84-4); 4,6-bis(octylthiomethyl)-o-cresol (LOWINOX™ 520 – CAS 110553-27-0); -di-t-butyl-4-hydroxyphenyl)propionate] (ANOX™70 – CAS 41484-35-9); dilauryl thiodipropionate (NAUGARD™ DLTDP – CAS 123-28- 4); distearyl thiodipropionate (NAUGARD™ DSTSP – CAS 693-36-7); ditridecylthiodipropionate (NAUGARD™ DTDTDP – CAS 10595-72-9);pentaerythritol tetrakis (p-laurylthiopropionate) (NAUGARD™ 412S – CAS 29598- 76-3); 2,4-bis(dodecylthiomethyl)-6-methylphenol (IRGANOX™ 1726 – CAS 110675-26-8, available from BASF); distearyl-disulfide (CAS 2500-88-1); -thiobis(2-tert-butyl-5-methylphenol) (LOWINOX™ TBM-6 – CAS 96-69- -thiobis(6-t-butyl-4-methylphenol) (LOWINOX™ TBP-6 – CAS 90-66-4); etc. and / or compatible mixtures of two or more thereof.

[0095] The sulphur containing antioxidant may be an inorganic antioxidant in the sense that it may comprise a metal. In this regard, the sulphur containing antioxidant may comprise one or more of a metal thiosulphate, a metal bisulphite, a metal metabisulphite, a metal hydrosulphite, etc. and / or compatible mixtures of two or more thereof. The metal thiosulphate may be selected from compounds with the formula: M2S2O3. The metal bisulphite may be selected from compounds with the formula: MHSO3. The metal metabisulphite may be selected from compounds with the formula: M2S2O5. The metal hydrosulphite may be selected from compounds with the formula: M2S2O4. The aforementioned “M” may refer to a metal. Depending on the particular antioxidant, the metal may be an alkali metal and / or an alkaline earth metal. The alkali metal may be lithium (Li), sodium (Na), or potassium (K). The alkaline earth metal may be calcium (Ca) or magnesium (Mg).

[0096] The foamed antioxidant masterbatch may include an aminic antioxidant. The aminic antioxidant may include, but is not limited to, acetone diphenylamine (AMINOX™ – CAS 68412-48-6); reaction products ofdiphenylamine and acetone (BLE™ – CAS 112-39- -diphenyl-p-phenylenediamine (FLEXAMINE™ – CAS 74-31- -(2-phenyl-2-propyl)phenyl]amine (NAUGARD™ 445 – CAS 10081-67-1); poly(1,2- dihydro-2,2,4-trimethylquinoline) (NAUGARD™ Q – CAS 26780-96-1);dioctyldiphenylamine (OCTAMINE™ – CAS 101-67-7); 1,4- -mixed phenyl and tolyl derivatives (NOVAZONE™ AS – CAS 68953-84-4); -- -dimethylpentyl)amino]phenyl]-1,3,5-triazine-2,4,6-triamine(DURAZONE™ 37 – CAS 121246-28-4); N-isopropyl- -phenyl-1,4-phenylenediamine (FLEXZONE™ 3C – CAS 101-72-4); N-phenyl-, reaction products with 2,4,4-trimethylpentene (NAUGARD™ PS30 – CAS 68411-46-1); N,N-bis-(1,4-dimethylpentyl)-p-phenylenediamine (FLEXZONE™ 4L – CAS 3081-14-9); diphenylamine (CAS 122-39-4); (1,3-dimethylbutyl)- -phenyl-p-phenylenediamine (CAS 793-24-8); etc. and / or compatible mixtures of two or more thereof.

[0097] The foamed antioxidant masterbatch may include an inorganic phosphite antioxidant. The inorganic phosphite antioxidant may comprise one or more of a metal phosphite, a metal hypophosphite, etc. and / or compatible mixtures of two or more thereof. The metal hypophosphite may be selected from compounds with the formula: MPO2H2. The aforementioned “M” may refer to a metal. Depending on the particular antioxidant, the metal may be an alkali metal and / or an alkaline earth metal. The alkali metal may be lithium (Li), sodium (Na), or potassium (K). The alkaline earth metal may be calcium (Ca) or magnesium (Mg). As one example, the inorganic phosphite antioxidant may be a metal hypophosphite. The metal hypophosphite may be sodium hypophosphite.

[0098] The metal hypophosphite may be in anhydrous form in one embodiment. Alternatively, the metal hypophosphite may be in hydrated form, such as a monohydrate metal hypophosphite.

[0099] The foamed antioxidant masterbatch may include a UV stabilizer. The UV stabilizer may include a hindered amine light stabilizer and / or a UV absorber. The UV stabilizer may include, but is not limited to, butanedioic acid, 1,4-dimethyl ester, polymer with 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol (LOWILITE™ 62 – CAS 65447-77-0); bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate(LOWILITE™ 77 – CAS 52829-07- - -tetramethylbutyl)amino]-1,3,5-triazine-2,4- -tetramethyl-4-piperidiyl)imino]-1,6--tetramethyl-4-piperidiyl)imino]]) (LOWILITE™ 94 – CAS70624-18-9); 1,5,8,12- -bis(N-butyl-N-1,2,2,6,6-pentamethylpiperidylamino)-1,3,5-triazin-2-yl]-1,5,8,12-tetraazadodecane (LOWILITE™ 19 – CAS 106990-43-6); bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (LOWILITE™ 92 – CAS 41556-26-7); salicylic acid derivatives such as phenyl salicylate, p-t-butyl salicylate, etc.; benzophenone system such as 2,4-dihydroxy benzophenone, 2-hydroxy-4-methoxybenzophenone, etc.; benzotriazole system such as 2- -hydroxy- -di-t-butylphenyl)benzotriazole, 2- -hydroxy- -t-butyl- -methylphenyl)-5-chlorobenzotriazole, etc.; hindered amine system such as bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethyl piperidine condensation product; 2- hydroxybenzophenones, e.g.2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4- -methylenebis(2-hydroxy-4-methoxybenzophenone); 2- -hydroxyphenyl)benzotriazoles, e.g.2- -hydroxy- -methylphenyl)benzotriazole, 2- -hydroxy- -t-octylphenyl)benzotriazole, 2- -hydroxy- -di-t-butylphenyl)benzotriazole, 2- -hydroxy- -di-t-butylphenyl)-5-chlorobenzotriazole, 2- -hydroxy- -t-butyl- -methylphenyl)-5-chlorobenzotriazole, 2- -hydroxy- --methylene bis(4-t-octyl-6- benzotriazolyl)phenol; benzoates, e.g. phenylsalicylate, resorcinol monobenzoate,2,4-di-t-butylphenyl- -di-t-butyl- -hydroxybenzoate, and hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate; substituted oxanilides, e.g. 2-ethyl- -ethoxyoxanilideand 2-ethoxy- -dodecyloxanilide; cyanoacrylates, e.g. ethyl- -cyano- -diphenylacrylate and methyl-2-cyano-3-methyl-3-(p-methoxyphenyl)acrylate, etc. and / or compatible mixtures of two or more thereof

[0100] Additional examples of hindered amine light stabilizers include 2,2,6,6-tetramethyl-4-piperidylstearate, 1,2,2,6,6-pentamethyl-4-piperidylstearate, 2,2,6,6-tetramethyl-4-piperidylbenzoate, bis(2,2,6,6-tetramethyl-4- piperidylsebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, tetrakis(2,2,6,6- tetramethyl-4-piperidyl)-1,2,3,4-butane tetracarboxylate, tetrakis(1,2,2,6,6- pentamethyl-4-piperidyl)-1,2,3,4-butane tetracarboxylate, bis(1,2,2,6,6- pentamethyl-4-piperidyl)-di(tridecyl)-1,2,3,4-butane tetracarboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-2-butyl-2- -di-t-butyl-4-hydroxybenzyl)malonate, 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-piperidinol / diethyl succinate polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino) hexane / dibromoethane polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane / 2,4-dichloro- 6-t-octyl amino-s-triazine polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4- piperidylamino)hexane / 2,4-dichloro-6-morphol ino-s-triazine polycondensate, etc. and / or compatible mixtures of two or more thereof. These mixtures may include any of the aforementioned UV stabilizers include those UV absorbers and hindered amine lights stabilizers mentioned above.

[0101] The foamed antioxidant masterbatch may include an acid scavenger. The acid scavenger may include one or more of a metal oxide, a metal hydroxide,a metal carbonate, a metal carboxylate, and / or a metal salt. In one embodiment, the acid scavenger may comprise a metal carboxylate. The metal carboxylate may include a metal stearate and / or a metal lactate. In one embodiment, the metal carboxylate comprises a metal stearate. The metal stearate may include, but is not limited to, calcium stearate, zinc stearate, aluminum stearate, magnesium stearate, lithium stearate, sodium stearate, cadmium stearate, barium stearate and / or a mixture of two or more thereof. The metal lactate may include, but is not limited to, sodium lactate, magnesium lactate, calcium lactate, zinc lactate and / or a mixture of two or more thereof. In one embodiment, the acid scavenger may include a metal oxide. The metal oxide may include, but is not limited to, zinc oxide, magnesium oxide, titanium dioxide, etc. or a mixture thereof. In one embodiment, the acid scavenger may include a metal carbonate. The metal carbonate may include, but is not limited to, calcium carbonate, hydrotalcite, a hydrotalcite-like compound, or a mixture thereof.

[0102] The foamed antioxidant masterbatch may include a clarifying agent and / or a nucleating agent. In one embodiment, the stabilizer composition may include a clarifying agent. In another embodiment, the stabilizer composition may include a nucleating agent. In a further embodiment, the stabilizer composition may include a clarifying agent and a nucleating agent. These agents may include a metal benzoate and / or a sorbitol derivative. The metal benzoate, if present, may comprise sodium benzoate, magnesium benzoate, calcium benzoate, zinc benzoate and / or a mixture of two or more thereof. These agents may include bis(3,4-dimethylbenzylidene) sorbitol (CAS 135861-56-2); bis(4-propylbenzylidene) sorbitol (CAS 882073-43-0); 2,4,8,10-tetra(tert-butyl)-6-hydroxy-12H- -oxide, sodium salt (CAS 85209-91-2); and / or compatible mixtures of two or more thereof.

[0103] The foamed antioxidant masterbatch may include a colorant. The colorant may include, but is not limited to, pigments, single pigment dispersions, dyes, talc filled resins, nano composites, coated micas, powdered aluminum and other metals, optical brighteners, fluorescents, phosphorescents, etc. as well as mixtures thereof.

[0104] In one embodiment, the colorant may include a pigment. The pigment may be an organic pigment, an inorganic pigment, or a mixture thereof.The organic pigment may include, but is not limited to, azo and disazo pigments such as azo and disazo lake, hansas, benzimidazolones, diarylides, pyrazolones, yellows and reds; polycyclic pigments such as phthalocyanines, quinacridones, perylenes, perinones, dioxazines, anthraquinones, isoindolins, thioindigo, diaryl or quinophthalone pigment, aniline black, or mixtures thereof. The inorganic pigment may include, but is not limited to, titanium oxide, titanium yellow, iron oxide, ultramarine blue, cobalt blue, chromic oxide green, lead yellow, cadmium yellow and cadmium red, carbon black pigments, and mixtures thereof. In one embodiment, the colorant may include carbon black. The organic and inorganic pigments can be used singly or in combination. These pigments may be in any form of a dry powder, pigment dispersions, or combinations thereof.

[0105] The foamed antioxidant masterbatch may include a flame retardant. Such flame retardant is not limited by the present disclosure. The flame retardant may include, but is not limited to, phosphoric acid systems such as allyl diallyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, triallyl phosphate, -chloroethyl)phosphate, tris(dichloropropyl)phosphate, tris(2,3-dibrompropyl)phosphate, tris(bromo- chloropropyl)phosphate, etc., chlorine systems such as chlorinated paraffin, chlorinated polyphenyl, perchloropentacyclodecane, etc., bromine systems such as tetrabromoethane, tetrabromobutane, hexaborombenzene, decabromodiphenyloxide, polydibrornophenyloxide, bis(tribromophenoxy)ethane, ethylene bisbromonorbornane dicarboxylmide, ethylene bistetrabromophthalimide, etc. reaction type such as chlorendic acid anhydride, tetrabromo phthalic anhydride, tetrabromo bisphenol A, dietoxy-bis-(2-hydroxyethyl)-aminomethyl phosphate, dibormcresyl glycidyl ether, etc. as well as mixtures thereof.

[0106] The foamed antioxidant masterbatch may include a filler. The filler may include, but is not limited to, glass filler (e.g., glass fibers, glass flakes, glass beads, etc.), talc, mica, clay, nano-clay, silica, or mixtures thereof. In one embodiment, the filler comprises a glass filler, such as glass fiber.

[0107] In general, while the above provides some examples of additives, it should be understood that other additives may also be utilized in accordance with the present disclosure.

[0108] Foaming Agent

[0109] As indicated herein, the masterbatch is a foamed antioxidant masterbatch. In this regard, the masterbatch has a foam structure. For instance, the masterbatch has a cell structure.

[0110] To form the foam structure, a foaming agent is utilized. The foaming agent may be a physical foaming agent, a chemical foaming agent, or a mixture thereof. The use of a particular foaming agent may dictate how the foam structure is generated. In one embodiment, the foaming agent comprises a physical foaming agent. In another embodiment, the foaming agent comprises a chemical foaming agent. In a further embodiment, the foaming agent comprises a physical foaming agent and a chemical foaming agent.

[0111] As indicated, the foaming agent may comprise a physical foaming agent in one embodiment. In general, such physical foaming agents may undergo a physical change of state during processing. The physical foaming agent may include a gas, a low boiling point liquid, a hydrocarbon, an ether, a ketone, or a mixture thereof.

[0112] For instance, in one embodiment, the physical foaming agent may include a gas, such as a pressurized gas. The gas may include, but is not limited to, nitrogen, carbon dioxide, methane, helium, neon, argon, xenon and hydrogen or a mixture thereof. More particularly, the gas may include carbon dioxide and / or nitrogen. When pressurized, the gas may expand when returning to atmospheric pressure during the process of foaming.

[0113] The physical foaming agent may include a low boiling point liquid, such as pentane, isopentane, hexane, methylene dichloride, or dichlorotetra- fluoroethane. Such liquids may expand when heated by changing from a liquid to a gaseous state and thereby producing a relatively higher volume of vapor to form the foam structure. Further, the low boiling point liquid may have a boiling temperature below the temperature at which the olefin polymer is in a partially or totally molten state.

[0114] The physical foaming agent may be a sublimation additive in one embodiment. For instance, a sublimation additive may be referred to as an additive that converts directly from a solid to a gas, without passing through the liquid state. In this regard, the gas, which may also be referred to as a sublimation gas, formed from the sublimation additive may be the foaming agent utilized informing the cell structure within the olefin polymer. Such gas may be any gas as mentioned herein, such as those mentioned above including carbon dioxide.

[0115] The sublimation temperature of such sublimation additive may be greater than ambient temperature. For instance, the sublimation temperature may be within the window at which the olefin polymer is processed in order to allow the sublimation additive to sublime and form a cellular structure within the olefin polymer. In this regard, it may be about or less than the temperature at which the olefin polymer is processed in forming the foam. For instance, the sublimation temperature may be greater than the melting temperature (Tm) of the olefin polymer. In particular, the sublimation temperature may be greater than the melting temperature (Tm) of the olefin polymer by 100°C or less, such as 80°C or less, such as 60°C or less, such as 50°C or less, such as 40°C or less, such as 30°C or less, such as 25°C or less, such as 20°C or less, such as 15°C or less, such as 10°C or less but 5°C or more, such as 10°C or more, such as 15°C or more, such as 20°C or more, such as 25°C or more greater than the melting temperature (Tm) of the olefin polymer.

[0116] The physical foaming agent may include a hydrocarbon. The hydrocarbon may include a saturated aliphatic hydrocarbon, a saturated alicyclic hydrocarbon, an aromatic hydrocarbon, a halogenated saturated hydrocarbon, etc. as well as mixtures thereof. The saturated aliphatic hydrocarbon may include, but is not limited to, methane, ethane, propane, butane, pentane, hexane, etc. as well as mixtures thereof. The saturated alicyclic hydrocarbon may include, but is not limited to, cyclopentane, cyclohexane, ethylcyclopentane, etc. as well as mixtures thereof. The aromatic hydrocarbon may include, but is not limited to, benzene, toluene, xylene, etc. as well as mixtures thereof. The halogenated saturated may include, but is not limited to, methylene chloride, carbon tetrachloride, etc. as well as mixtures thereof.

[0117] The physical foaming agent may include an ether. The ether may include, but is not limited to, methylal, 1,4-dioxane, etc. as well as mixtures thereof. The physical foaming agent may include a ketone. The ketone may include, but is not limited to, acetone, methyl ethyl ketone, acetyl ketone, etc. as well as mixtures thereof.

[0118] When utilizing a physical foaming agent, it may be provided in a microcapsule. For instance, the microcapsule may be a thermally expandable microcapsule in one embodiment. For instance, such microcapsule may include a polymeric shell. The core may include a physical foaming agent as defined above. The polymeric shell is not necessarily limited and may be formed any polymer generally known in the art capable of functioning as a shell for the physical foaming agent and for being processed with the olefin polymer as disclosed herein.

[0119] As indicated, the foaming agent may comprise a chemical foaming agent in one embodiment. In general, “chemical foaming agents” refer to foaming agents that undergo a decomposition reaction during heating at a given temperature, leading to the release of gas, such as nitrogen, carbon dioxide, carbon monoxide, nitroxide, NOx compounds, ammonia and / or water vapor. In one embodiment, the released gas may be carbon dioxide, water vapor, or a mixture thereof.

[0120] Such chemical foaming agents may include, but are not limited to, azides; hydrazides such as 4,4'-oxybisbenzenesulfonate (aka -hydroxybis- (benzenesulfonyl hydrazide)), 1,3-benzenesulfonyl hydrazide, diphenyl sulfone- 3,3'-disulfohydrazide; semicarbazides such as p-toluenesulfonyl semicarbazide, p- toluenesulfonyl semicarbazide; azocompounds such as azodicarbonamide (aka azodicarboxamide); triazoles such as nitrotriazolone; tetrazoles such as 5- phenyltetrazole; azodicarboxylates such as barium azodicarboxylate, diisopropyl azodicarboxylate, diethyl azodicarboxylate; N,N-dinitroso pentamethylene tetramine; methylenetetramine; azodiisobutyronitrile; azoaminobenzene; citric acid or citrates; carbonates such as alkali carbonates such as sodium carbonate; bicarbonates such as zinc bicarbonate or alkali bicarbonates such as sodium bicarbonate; anhydride; peroxide; nitrocompounds such as nitroguanidine; perchlorates; etc. as well as mixtures thereof.

[0121] In one embodiment, the foaming agent may comprise a chemical foaming agent. The foaming agent may comprise a carbonate, a bicarbonate, or a mixture thereof. In one embodiment, the foaming agent may comprise a bicarbonate. For instance, the bicarbonate may comprise zinc bicarbonate, sodium carbonate, or a mixture thereof. In one embodiment, the bicarbonate may comprise an alkali carbonate. The alkali may include, but is not limited to, lithium,sodium, or potassium. In one particular embodiment, the foaming agent, such as the chemical foaming agent, may comprise sodium bicarbonate.

[0122] In one embodiment, the chemical foaming agent may comprise a mixture of citric acid or a citrate and a carbonate and / or a bicarbonate. In another embodiment, the chemical foaming agent may comprise hydrogen peroxide.

[0123] In one embodiment, the foaming agent may be used in conjunction with a foaming aid. For instance, the foaming aid may assist in the foaming. For instance, in one embodiment, the foaming aid may be a foaming accelerator. The foaming accelerator may be utilized to accelerate the decomposition of any particular foaming agents, reduce the decomposition temperature, and / or narrow the decomposition temperature range.

[0124] The foaming accelerator may be an acid, a base, a metal organic salt, a metal inorganic salt, an oxide, an amine, urea, or a combination thereof. Such foaming accelerator should be selected based on the foaming agent utilized in the foaming process. In one embodiment, the foaming accelerator may be a metal organic salt. In another embodiment, the foaming accelerator may be a metal inorganic salt. While such metal is not necessarily limited, in one embodiment, the metal may be zinc. For instance, the foaming accelerator may include, but is not limited to, zinc oxide, zinc stearate, zinc carbonate, zinc chloride, zinc propionate, zinc nitrate, zinc laurate, zinc octoate, or a mixture thereof. In one embodiment, the foaming accelerator may include zinc oxide, zinc stearate, zinc carbonate, or a mixture thereof. In one particular embodiment, the foaming accelerator may include zinc stearate.

[0125] The foaming aid, such as the foaming accelerator, may be present in an amount of about 0.1 parts or more, such as about 0.3 parts or more, such as about 0.5 parts or more, such as about 0.8 parts or more, such as about 1 parts or more, such as about 2 parts or more, such as about 3 parts or more, such as about 4 parts or more, such as about 5 parts or more, such as about 8 parts or more, such as about 10 parts or more, such as about 15 parts or more, such as about 20 parts or more based on the total parts of the foaming agent. The foaming aid may be present in an amount of about 30 parts or less, such as about 25 parts or less, such as about 20 parts or less, such as about 18 parts or less, such as about 15 parts or less, such as about 13 parts or less, such as about 10 parts orless, such as about 8 parts or less, such as about 6 parts or less, such as about 4 parts or less, such as about 5 parts or less, such as about 3 parts or less, such as about 2 parts or less, such as about 1 parts or less based on the total parts of the foaming agent.

[0126] In general, it should be understood that any combination of the aforementioned physical foaming agents and chemical foaming agents may be utilized. Further, if only utilizing physical foaming agents, any combination of such foaming agents may be utilized. Further, if only utilizing chemical foaming agents, any combination of such chemical agents may be utilized.

[0127] The foaming agent may be provided to a chamber as defined herein for foaming in a particular amount. For instance, the foaming agent may be provided in an amount of about 0.1 wt.% or more, such as about 0.2 wt.% or more, such as about 0.3 wt.% or more, such as about 0.5 wt.% or more, such as about 0.8 wt.% or more, such as about 1 wt.% or more, such as about 1.3 wt.% or more, such as about 1.5 wt.% or more, such as about 1.8 wt.% or more, such as about 2 wt.% or more, such as about 2.3 wt.% or more, such as about 2.5 wt.% or more, such as about 2.8 wt.% or more, such as about 3 wt.% or more, such as about 3.3 wt.% or more, such as about 3.5 wt.% or more, such as about 3.8 wt.% or more, such as about 4 wt.% or more, such as about 4.5 wt.% or more, such as about 5 wt.% or more, such as about 6 wt.% or more, such as about 7 wt.% or more, such as about 8 wt.% or more, such as about 9 wt.% or more based on the weight of the olefin polymer. The foaming agent may be provided in an amount of about 15 wt.% or less, such as about 13 wt.% or less, such as about 10 wt.% or less, such as about 8 wt.% or less, such as about 6 wt.% or less, such as about 5 wt.% or less, such as about 4.5 wt.% or less, such as about 4 wt.% or less, such as about 3.5 wt.% or less, such as about 3 wt.% or less, such as about 2.5 wt.% or less, such as about 2 wt.% or less, such as about 1.5 wt.% or less, such as about 1 wt.% or less based on the weight of the olefin polymer. In one embodiment, such aforementioned weight percentages may be based on the weight of the olefin polymer and the one or more organic phosphite antioxidants. In another embodiment, such aforementioned weight percentages may be based on the weight of the one or more organic phosphite antioxidants.

[0128] Forming the Masterbatch

[0129] As indicated herein, the masterbatch is a foamed antioxidant masterbatch. In this regard, the masterbatch has a foam structure. For instance, the masterbatch has a cell structure. In this regard, the foamed antioxidant masterbatch may be made using techniques generally known in the art.

[0130] Before forming the masterbatch, any one or more of the components may be premixed using any mixing device generally known in the art. In the device, the one or more components may be added together and mixed or added individually at any point during the mixing process.

[0131] The masterbatch may be formed in any suitable device using a variety of techniques. For instance, processing may include melt blending, in a chamber, the olefin polymer, one or more organic phosphite antioxidants, and a foaming agent. In addition, to the extent included, any other additives may also be mixed or blended with the olefin polymer, the one or more organic phosphite antioxidants, and the foaming agent.

[0132] In such process, the foaming agent may be introduced in the chamber before heating, during heating, and / or when the olefin polymer has been heated and is already in a molten state. In one embodiment, the foaming agent, such as the chemical foaming agent, may be introduced with the olefin polymer at ambient conditions and then provided to the chamber. In another embodiment, the olefin polymer may be provided to the chamber and thereafter the foaming agent may be introduced to the chamber, either as a mixture or individually. For instance, at least a portion of the foaming agent, or all the foaming agent, may be provided to the olefin polymer after the polymer has been heated and in an at least partially molten state. Regardless, such foaming agent may be provided in a manner to allow for dispersion of the foaming agent within the olefin polymer for formation of the cells.

[0133] The chamber may be any vessel that is suitable for blending the selected components under temperature and shearing force conditions necessary to form a foamed antioxidant masterbatch. In this respect, the chamber may be a mixer, such as Banbury™ mixers or Brabender™ mixers, and certain mixing extruders such as co-rotating, counter-rotating, and twin-screw extruders, as well as co-kneaders, such as Buss® kneaders. According to one embodiment, the chamber is an extruder, which may be a single or multi-screw extruder. The term“multi-screw extruder” means an extruder having two or more screws. The screws of the extruder may have a plurality of lobes. It will readily be understood that other screw designs may be selected in accordance with the methods of embodiments of the present disclosure. In some embodiments, foaming may occur during and / or as a result of extrusion. After discharging from the apparatus, the foamed antioxidant masterbatch may be milled, chopped, pelletized, or processed by any other desirable technique.

[0134] The foaming may be performed within the chamber. Such foaming may be performed at a temperature at which the olefin polymer is in an at least partially molten status, such as a totally molten state. Particularly, the foaming may be performed at a temperature above the crystallization temperature (Tc) of the olefin polymer. For instance, the olefin polymer may be subjected to a temperature at or above the melting temperature (Tm) of the olefin polymer. For instance, the temperature for extrusion may be greater than the melting temperature (Tm) of the olefin polymer by 100°C or less, such as 80°C or less, such as 60°C or less, such as 50°C or less, such as 40°C or less, such as 30°C or less, such as 25°C or less, such as 20°C or less, such as 15°C or less, such as 10°C or less but 5°C or more, such as 10°C or more, such as 15°C or more, such as 20°C or more, such as 25°C or more greater than the melting temperature (Tm) of the olefin polymer.

[0135] During the foaming, one or more cells (also called bubbles) are created in the structure of the olefin polymer via the foaming agent. The gas generated by said foaming agent creates bubbles or cells within the molten or the partially molten olefin polymer, forming closed-cells and / or opened-cells in the olefin polymer. The resulting foamed olefin polymer exhibits a cellular structure, which has a lower density than the density of the olefin polymer before the foaming step. In this regard, the density of the foamed antioxidant masterbatch is less than the density of the pre-molten olefin polymer prior to the foaming step.

[0136] The cell structure, comprising one or more cells, may be an open-cell structure in one embodiment. In this regard, the one or more cells may comprise open cells. In another embodiment, the cell structure, comprising one or more cells, may be a closed-cell structure. In this regard, the one or more cells may comprise closed cells. In a further embodiment, the cell structure, comprising oneor more cells, may include a combination of open-cells and closed-cells. In this regard, the one or more cells may comprise a combination of open cells and closed cells.

[0137] In one embodiment, the cell structure may have an open cell geometry or constitute an open-celled structure. In general, such structures generally contain interconnected cells, which allow for the passage of gas or a fluid through the void space from one cell to the next. This is contrary to closed-cell structures, which may not have interconnected cell openings. In some embodiments, at least 0.01% to about 100% of the one or more cells contain an open cell geometry. In some embodiments, at least 10% to about 90% of the one or more cells contain an open cell geometry. In some embodiments, at least about 20% to about 80% of the one or more cells contain an open cell geometry. Accordingly, in certain embodiments, at least 0.01%, such as at least 1%, such as at least 10%, such as at least 20%, such as at least 30%, such as at least 40%, such as at least 50%, such as at least 60%, such as at least 70%, such as at least 80%, such as at least 90% of the one or more cells contain an open cell geometry. In addition, in certain embodiments, 100% or less, such as 95% or less, such as 90% or less, such as 85% or less, such as 80% or less, such as 75% or less, such as 70% or less, such as 60% or less, such as 50% or less, such as 40% or less, such as 30% or less, such as 20% or less, such as 10% or less of the one or more cells contain an open cell geometry. In some embodiments, about 0% of the cells contain an open cell geometry.

[0138] In one embodiment, the cell structure may have a closed cell geometry or constitute a closed-celled structure. In general, such structures are those in which the cells are enclosed and may be tightly pressed together. In some embodiments, at least 0.01% to about 100% of the one or more cells contain a closed cell geometry. In some embodiments, at least 10% to about 90% of the one or more cells contain a closed cell geometry. In some embodiments, at least about 20% to about 80% of the one or more cells contain a closed cell geometry. Accordingly, in certain embodiments, at least 0.01%, such as at least 1%, such as at least 10%, such as at least 20%, such as at least 30%, such as at least 40%, such as at least 50%, such as at least 60%, such as at least 70%, such as at least 80%, such as at least 90% of the one or more cells contain a closed cell geometry.In addition, in certain embodiments, 100% or less, such as 95% or less, such as 90% or less, such as 85% or less, such as 80% or less, such as 75% or less, such as 70% or less, such as 60% or less, such as 50% or less, such as 40% or less, such as 30% or less, such as 20% or less, such as 10% or less of the one or more cells contain a closed cell geometry.

[0139] Related, the foamed antioxidant masterbatch may have a particular porosity rate. For instance, the porosity rate may be between 10% and 90%. For instance, the porosity rate may be 10% or more, such as 20% or more, such as 30% or more, such as 40% or more, such as 50% or more, such as 60% or more, such as 70% or more. The porosity rate may be 90% or less, such as 80% or less, such as 70% or less, such as 60% or less, such as 50% or less, such as 40% or less, such as 30% or less, such as 20% or less. As used herein, the term “porosity rate” refers to the void fraction in the foamed antioxidant masterbatch and corresponds to the ratio volume of voids (i.e. cells) within the foamed antioxidant masterbatch to the total volume of the foamed antioxidant masterbatch. The porosity rate can be estimated by any method known by a person skilled in the art.

[0140] The cells may be micro- or nano-scale in size. In one embodiment, the cells may be microscale. In another embodiment, the cells may be nanoscale. In a further embodiment, the cells may be a mixture of microscale and nanoscale. The average cell size may be 0.02 microns or more, such as 0.03 microns or more, such as 0.05 microns or more, such as 0.1 microns or more, such as 0.2 microns or more, such as 0.3 microns or more, such as 0.4 microns or more, such as 0.5 microns or more, such as 0.6 microns or more, such as 0.7 microns or more, such as 0.8 microns or more, such as 0.9 microns or more, such as 1 microns or more, such as 2 microns or more, such as 3 microns or more, such as 4 microns or more, such as 5 microns or more, such as 8 microns or more, such as 10 microns or more, such as 15 microns or more, such as 20 microns or more, such as 25 microns or more, such as 30 microns or more, such as 40 microns or more, such as 50 microns or more, such as 70 microns or more, such as 100 microns or more, such as 150 microns or more, such as 200 microns or more. The average cell size may be 300 microns or less, such as 275 microns or less, such as 250 microns or less, such as 225 microns or less, such as 200 microns or less, such as 175 microns or less, such as 150 microns or less, such as 125 microns orless, such as 100 microns or less, such as 90 microns or less, such as 80 microns or less, such as 70 microns or less, such as 60 microns or less, such as 50 microns or less, such as 45 microns or less, such as 40 microns or less, such as 35 microns or less, such as 30 microns or less, such as 25 microns or less, such as 20 microns or less, such as 15 microns or less, such as 10 microns or less, such as 5 microns or less, such as 3 microns or less, such as 1 microns or less, such as 0.9 microns or less, such as 0.8 microns or less, such as 0.7 microns or less, such as 0.6 microns or less, such as 0.5 microns or less, such as 0.4 microns or less.

[0141] Such average cell size may be determined using techniques generally known in the art, particularly utilizing microscopy techniques. For instance, at least 3 images of cross sections of the foamed antioxidant masterbatch may be analyzed to determine the average cell size of the cells. For determining an individual cell size, the longest dimension may be utilized.

[0142] With such cell structure, particularly a closed cell structure, the one or more organic phosphite antioxidants may be provided and retained within the olefin polymer, such as the cells formed therein, for providing a foamed antioxidant masterbatch. In one embodiment, such cells may also contain or include any other additives employed in the foamed antioxidant masterbatch.

[0143] Applications

[0144] Once formed, the foamed antioxidant masterbatch may be utilized downstream. For instance, the foamed antioxidant masterbatch may be introduced or mixed with any compatible polymer and processed accordingly to form a polymer composition from a second polymer and the foamed antioxidant masterbatch.

[0145] Such second polymer may be an olefin polymer as defined herein. In one embodiment, the second polymer may be the same olefin polymer as in the foamed antioxidant masterbatch. In another embodiment, the second polymer may be a different polymer from the foamed antioxidant masterbatch. Regardless, the second polymer may be any polymer as mentioned above with respect to the olefin polymer.

[0146] The polymer composition may be formed in any suitable device using a variety of techniques. For instance, processing may include melt blending, in achamber, the second polymer and the foamed antioxidant masterbatch. In addition, additives, such as those defined above with respect to the foamed antioxidant masterbatch, may also be mixed or blended with the second polymer and the foamed antioxidant masterbatch.

[0147] The loading of the foamed antioxidant masterbatch in the polymer may be adjusted as needed depending on the particular application and desired properties. For instance, such loading may be dictated by the target loading of the one or more phosphite antioxidants in the resulting polymer composition.

[0148] The chamber may be any vessel that is suitable for blending the selected components under temperature and shearing force conditions necessary to form a polymer composition. In this respect, the chamber may be a mixer, such as Banbury™ mixers or Brabender™ mixers, and certain mixing extruders such as co-rotating, counter-rotating, and twin-screw extruders, as well as co-kneaders, such as Buss® kneaders. According to one embodiment, the chamber is an extruder, which may be a single or multi-screw extruder. The term “multi-screw extruder” means an extruder having two or more screws. The screws of the extruder may have a plurality of lobes. It will readily be understood that other screw designs may be selected in accordance with the methods of embodiments of the present disclosure. After discharging from the apparatus, the polymer composition may be milled, chopped, pelletized, molded or processed by any other desirable technique.

[0149] The foamed antioxidant masterbatch and the resulting polymer composition may be utilized to form an article. For instance, the polymer composition may be shaped into the form of an article using any of a variety of techniques as is known in the art. For instance, the polymer composition can advantageously be fabricated by employing typical molding processes, such as injection molding, extrusion molding, compression molding, blow molding, rotational molding, overmolding, etc. In general, these processes include heating the polymer composition to a temperature that is equal to or in excess of the melt temperature of the second polymer and / or the olefin polymer to form a pre-form for a mold cavity to then form the article, cooling the article to a temperature at or below the crystallization temperature of the second polymer and / or the olefin polymer, and releasing the article from a mold. The mold cavity defines the shapeof the article. The process may also utilize extrusion molding. In this regard, the polymer composition may be extruded as described herein. Upon exiting the extruder, the polymer composition may be formed or shaped to a desired article. Such article may be formed by using a particular die to shape the polymer composition as it exits the extruder. Such shaping / forming process, such as the extrusion process, may be an automated or robotic process.

[0150] Related, the polymer composition may be utilized to form a film or sheet. Such film / sheet may be formed using techniques generally known in the art. For instance, such film / sheet may be formed using extrusion using standard extrusion techniques. These techniques may include, but are not limited to, cast film extrusion or blown film extrusion.

[0151] The polymer composition as disclosed herein may be utilized in a variety of applications and such applications are not limited by the present disclosure. Examples Example 1

[0152] Foamed antioxidant masterbatches were prepared using phosphorous acid, mixed 2,4-bis(1,1-dimethylpropyl)phenyl and 4-(1,1- dimethylpropyl)phenyl triesters (WESTON™ 705 – CAS 939402-02-5) containing triisopropanolamine as the phosphite antioxidant. The foaming agent was sodium bicarbonate and the polymer was LLDPE. The formulations are provided in the table below.

[0153] Table 1. Foamed Antioxidant Masterbatch Formulations

[0154] Figure 1 illustrates the hydrolysis stability of the organic phosphite antioxidant of the foamed antioxidant masterbatch of Sample No.1. Example 2

[0155] Foamed antioxidant masterbatches were prepared using phosphorous acid, mixed 2,4-bis(1,1-dimethylpropyl)phenyl and 4-(1,1- dimethylpropyl)phenyl triesters (WESTON™ 705 – CAS 939402-02-5) as the phosphite antioxidant. Certain samples contained triisopropanolamine as a Lewis base. The foaming agent was sodium bicarbonate and the polymer was LLDPE.

[0156] The foamed antioxidant masterbatch exhibited reduced WESTON™ 705T blooming and improved organic phosphite antioxidant hydrolysis stability compared to an unfoamed antioxidant masterbatch as illustrated in Figure 2. In addition, incorporation of trace amounts of triisopropanolamine also assisted in the increase of organic phosphite antioxidant hydrolysis stability as illustrated in Figure 3.

[0157] Figure 4 illustrates an LLDPE / Weston™ 705T (12 wt.%) foamed antioxidant masterbatch using NaHCO3(0.5 wt.%) as the chemical foaming agent and triisopropanolamine (0.3 wt.%), where pellets remain dry and free flowing with very little hydrolysis after > 6 weeks under relatively harsh conditions (50°C / 80% humidity). Similarly, LLDPE / Weston™ 705T (15 wt.%-20 wt.%) foamed antioxidant masterbatches can be prepared that remain dry and free of hydrolysis under relatively harsh conditions (50°C / 80% humidity). Example 3

[0158] Foamed antioxidant masterbatches were prepared using phosphorous acid, mixed 2,4-bis(1,1-dimethylpropyl)phenyl and 4-(1,1- dimethylpropyl)phenyl triesters (WESTON™ 705 – CAS 939402-02-5) as the phosphite antioxidant at loadings of 10 wt.% and 15 wt.%. The samples contained triisopropanolamine as a Lewis base. The foaming agent was sodium bicarbonate (1.5 wt.%), zinc oxide (5 wt.%), and the balance was LLDPE as the olefin polymer.

[0159] These and other modifications and variations of the present disclosure may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present disclosure. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only and is not intended to limit the disclosure so further described in such appended claims.

Claims

Claims 1. A foamed antioxidant masterbatch comprising an olefin polymer and one or more organic phosphite antioxidants, wherein the foamed antioxidant masterbatch comprises a cell structure comprising one or more cells, wherein the one or more organic phosphite antioxidants is provided in the one or more cells.

2. The foamed antioxidant masterbatch of any preceding claim, wherein the olefin polymer comprises a linear low-density polyethylene, a very low-density polyethylene, a low-density polyethylene, or a mixture thereof.

3. The foamed antioxidant masterbatch of any preceding claim, wherein the olefin polymer comprises a linear low-density polyethylene.

4. The foamed antioxidant masterbatch of any preceding claim, wherein the olefin polymer is present in an amount of 40 wt.% or more based on the weight of the foamed antioxidant masterbatch.

5. The foamed antioxidant masterbatch of any preceding claim, wherein the olefin polymer is present in an amount of 70 wt.% or more based on the weight of the foamed antioxidant masterbatch.

6. The foamed antioxidant masterbatch of any preceding claim, wherein the one or more organic phosphite antioxidants comprise a triaryl phosphite, a trialkyl phosphite, an alkylphenol-free polymeric polyphosphite, or a mixture thereof.

7. The foamed antioxidant masterbatch of any preceding claim, wherein the one or more organic phosphite antioxidants comprise a triaryl phosphite.

8. The foamed antioxidant masterbatch of any preceding claim, wherein the one or more organic phosphite antioxidants comprise phosphorous acid, mixed 2,4-bis(1,1-dimethylpropyl)phenyl and 4-(1,1-dimethylpropyl)phenyl triesters.

9. The foamed antioxidant masterbatch of any preceding claim, wherein the one or more organic phosphite antioxidants are a liquid at ambient conditions (atmospheric pressure and a temperature of 25°C).

10. The foamed antioxidant masterbatch of any preceding claim, wherein the one or more organic phosphite antioxidants is present in an amount of from 3wt.% or more to 45 wt.% or less based on the weight of the foamed antioxidant masterbatch.

11. The foamed antioxidant masterbatch of any preceding claim, wherein the one or more organic phosphite antioxidants is present in an amount of from 5 wt.% or more to 40 wt.% or less based on the weight of the foamed antioxidant masterbatch.

12. The foamed antioxidant masterbatch of any preceding claim, further comprising an acid scavenger.

13. The foamed antioxidant masterbatch of claim 12, wherein the acid scavenger comprises zinc oxide, magnesium oxide, titanium dioxide, or a mixture thereof.

14. The foamed antioxidant masterbatch of any preceding claim, wherein at least 10% to 90% of the one or more cells of the cell structure contain a closed cell geometry.

15. The foamed antioxidant masterbatch of any preceding claim, wherein an average cell size of the one or more cells is 0.02 microns or more to 300 microns or less.

16. A method of making the foamed antioxidant masterbatch of any preceding claim, the method comprising: melt blending the olefin polymer, the one or more organic phosphite antioxidants, and a foaming agent; wherein the foaming agent forms the one or more cells in the olefin polymer.

17. The method of claim 16, wherein the foaming agent comprises a chemical foaming agent.

18. The method of claim 16 or 17, wherein the foaming agent comprises a carbonate, a bicarbonate, or a mixture thereof.

19. The method of any one of claims 16-18, wherein the foaming agent comprises zinc bicarbonate, sodium carbonate, or a mixture thereof.

20. A method of making a polymer composition, the method comprising: melt blending the foamed antioxidant masterbatch of claim 1 with a second polymer.

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