Crosslinkable ethylene polymer-based thermoplastic vulcanizates and molded articles made therefrom

Abstract

Molded articles are disclosed that include crosslinked thermoplastic vulcanizates that include a crosslinked ethylene polymer and an at least partially cured elastomer. Methods for making such molded articles are also disclosed. The disclosure is also directed to crosslinkable thermoplastic vulcanizates that include a crosslinkable ethylene polymer and an at least partially cured elastomer.

Description

[Background technology]

[0001]

[0001] Crosslinked polyethylene is one of the primary plastic materials commonly used in a variety of applications. For example, the thermomechanical properties of crosslinked polyethylene enable its use in certain applications, such as wire and cable, pipes, tubing, and the like. To crosslink polyethylene, certain crosslinking techniques are generally used. In addition, crosslinked polyethylene may not be as flexible as desired for certain applications. As a result, there is a need to provide ethylene polymer-based materials with improved flexibility that enable their use in certain applications while maintaining improved properties, particularly mechanical properties. Summary of the Invention [Means for solving the problem]

[0002]

[0002] According to one embodiment of the present disclosure, a molded article is disclosed, the molded article comprising a crosslinked thermoplastic vulcanizate comprising a crosslinked ethylene polymer and an at least partially cured elastomer.

[0003] According to another embodiment of the present disclosure, there is disclosed a method of forming a molded article, the method comprising the steps of blending a crosslinking agent and a crosslinkable ethylene polymer and a crosslinkable thermoplastic vulcanizate comprising an at least partially cured elastomer to form a first blend, forming the first blend into the shape of a molded article, and crosslinking the crosslinkable ethylene polymer to obtain a crosslinked ethylene polymer and a crosslinked thermoplastic vulcanizate.

[0004] According to another embodiment of the present disclosure, a method of forming a molded article is disclosed, the method comprising: forming a crosslinkable thermoplastic vulcanizate, including a crosslinkable ethylene polymer and an at least partially cured elastomer, into the shape of a molded article; and crosslinking the crosslinkable ethylene polymer by exposure to radiation to obtain a crosslinked ethylene polymer and a crosslinked thermoplastic vulcanizate.

[0005] According to another embodiment of the present disclosure, a method of forming a molded article is disclosed, the method comprising the steps of providing a thermoplastic vulcanizate formulation including a crosslinkable ethylene polymer, an elastomer, a curative, and a crosslinking agent; dynamically vulcanizing the elastomer with the curative to form a crosslinkable thermoplastic vulcanizate; forming the crosslinkable thermoplastic vulcanizate into the shape of a molded article; and crosslinking the crosslinkable ethylene polymer to obtain a crosslinked ethylene polymer and a crosslinked thermoplastic vulcanizate.

[0006] According to another embodiment of the present disclosure, a method of forming a molded article is disclosed, comprising the steps of providing a thermoplastic vulcanizate formulation including a crosslinkable ethylene polymer, an elastomer, and a curative; dynamically vulcanizing the elastomer with the curative to form a crosslinkable thermoplastic vulcanizate; forming the crosslinkable thermoplastic vulcanizate into the shape of a molded article; and crosslinking the crosslinkable ethylene polymer by exposure to radiation to provide a crosslinked ethylene polymer and a crosslinked thermoplastic vulcanizate.

[0007]

[0007] According to another embodiment of the present disclosure, a crosslinkable thermoplastic vulcanizate is disclosed. The crosslinkable thermoplastic vulcanizate includes a crosslinkable ethylene polymer and an at least partially cured elastomer. The crosslinkable ethylene polymer has at least 50 mol% ethylene and 0 to less than 20 mol% propylene, and is present in an amount of 15 wt% or more to 60 wt% or less, based on the combined weight of the crosslinkable ethylene polymer and the at least partially cured elastomer. The crosslinkable thermoplastic vulcanizate includes 5 wt% or less to 0 wt% propylene polymer, based on the weight of the crosslinkable thermoplastic vulcanizate, and the propylene polymer includes 60 mol% or more propylene units.

[0008] According to another embodiment of the present disclosure, a crosslinked thermoplastic vulcanizate is disclosed. The crosslinked thermoplastic vulcanizate includes a crosslinked ethylene polymer and an at least partially cured elastomer. The crosslinked ethylene polymer is formed from an ethylene polymer having at least 50 mol% ethylene and 0 to less than 20 mol% propylene.

[0009]

[0009] Other features and aspects of the present disclosure are set forth in more detail below.

[0010] A full and enabling disclosure of the present disclosure, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying drawings. [Brief explanation of the drawings]

[0010] [Figure 1]

[0011] FIG. 10 illustrates the results of the DMTA analysis in Example 17. [Figure 2]

[0012] FIG. 10 illustrates the results of the DMTA analysis in Example 18. DETAILED DESCRIPTION OF THE INVENTION

[0011]

[0013] It will be understood by those skilled in the art that the discussion of the present invention is a description of exemplary embodiments only and is not intended to limit the broader aspects of the present disclosure.

[0014] In general, the present disclosure is directed to the use of crosslinkable thermoplastic vulcanizates comprising a crosslinkable ethylene polymer and an at least partially cured elastomer dispersed in the crosslinkable ethylene polymer. In particular, such crosslinkable thermoplastic vulcanizates can be crosslinked to provide crosslinked thermoplastic vulcanizates. For example, such crosslinked thermoplastic vulcanizates can comprise a crosslinked ethylene polymer and an at least partially cured elastomer dispersed in the crosslinked ethylene polymer. Such crosslinkable and crosslinked thermoplastic vulcanizates can be used to form various molded articles.

[0012]

[0015] The inventors have discovered that the use of such materials can offer many advantages, including maintaining strength even in the crosslinked thermoplastic phase, thereby enabling their use in a variety of applications. For example, thermoplastic vulcanizates can exhibit a specific Shore A hardness (ISO 868:2003; 15 seconds), which is used to measure the hardness of the thermoplastic vulcanizate and provide an indication of its resistance to indentation. In this regard, the thermoplastic vulcanizate can have a Shore A hardness of 25 to 100. For example, the thermoplastic vulcanizate can have a Shore A hardness of 25 or more, such as 30 or more, 35 or more, such as 40 or more, such as 45 or more, such as 50 or more, such as 55 or more, such as 60 or more, or such as 65 or more. The thermoplastic vulcanizate can have a Shore A hardness of 100 or less, such as 95 or less, such as 90 or less, such as 80 or less, such as 70 or less, such as 65 or less, such as 60 or less, such as 55 or less, such as 50 or less, or such as 45 or less. In one embodiment, the above Shore A hardnesses may apply to crosslinkable thermoplastic vulcanizates as defined herein. In another embodiment, the above Shore A hardnesses may apply to crosslinked thermoplastic vulcanizates as defined herein. Such hardnesses allow the thermoplastic vulcanizates to provide compliance and flexibility to function effectively for a particular application.

[0013]

[0016] In addition, the thermoplastic vulcanizate may exhibit a certain strength as indicated by certain mechanical properties. For example, the thermoplastic vulcanizate may exhibit a 100% modulus (ASTM D412-16) of at least 0.3 MPa, e.g., 0.5 to 5 MPa. For example, the 100% modulus may be 0.3 MPa or more, such as 0.4 MPa or more, for example, 0.5 MPa or more, for example, 0.8 MPa or more, for example, 1 MPa or more, for example, 1.1 MPa or more, for example, 1.2 MPa or more, for example, 1.3 MPa or more, for example, 1.4 MPa or more, for example, 1.5 MPa or more, for example, 2 MPa or more, for example, 2.5 MPa or more, for example, 3 MPa or more, for example, 4 MPa or more, for example, 5 MPa or more, for example, 6 MPa or more, for example, 10 MPa or more, for example, 20 MPa or more, or for example, 30 MPa or more. The 100% modulus may be 50 MPa or less, such as 40 MPa or less, for example, 30 MPa or less, for example, 25 MPa or less, for example, 20 MPa or less, for example, 15 MPa or less, for example, 10 MPa or less, for example, 8 MPa or less, for example, 6 MPa or less, for example, 5 MPa or less, for example, 4.5 MPa or less, for example, 4 MPa or less, for example, 3.8 MPa or less, for example, 3.5 MPa or less, for example, 3.3 MPa or less, for example, 3 MPa or less, for example, 2.8 MPa or less, for example, 2.5 MPa or less, for example, 2.3 MPa or less, for example, 2 MPa or less, for example, 1.9 MPa or less, for example, 1.8 MPa or less, for example, 1.5 MPa or less, for example, 1.3 MPa or less, for example, 1.1 MPa or less, for example, 0.8 MPa or less. In one embodiment, the above 100% modulus is applicable to crosslinkable thermoplastic vulcanizates as defined herein. In another embodiment, the above 100% modulus is applicable to crosslinked thermoplastic vulcanizates as defined herein.

[0014]

[0017] The thermoplastic vulcanizate may also exhibit a tensile stress at break (or ultimate tensile strength) of 0.5 to 50 MPa, such as 1 to 20 MPa, for example, 2 to 10 MPa. For example, the thermoplastic vulcanizate may exhibit a tensile stress of 0.5 MPa or more, such as 1 MPa or more, for example, 1.5 MPa or more, for example, 2 MPa or more, such as 2.5 MPa or more, for example, 3 MPa or more, such as 3.5 MPa or more, for example, 4 MPa or more, such as 5 MPa or more, for example, 6 MPa or more, for example, 7 MPa or more, such as 10 MPa or more, for example, 15 MPa or more, such as 20 MPa or more, for example, 30 MPa or more, such as 40 MPa or more, for example, 50 MPa or more, for example, 60 MPa or more, for example, 70 MPa or more. The tensile stress may be 100 MPa or less, such as 80 MPa or less, for example 60 MPa or less, for example 50 MPa or less, for example 40 MPa or less, for example 30 MPa or less, for example 25 MPa or less, for example 20 MPa or less, for example 18 MPa or less, such as 15 MPa or less, for example 13 MPa or less, for example 11 MPa or less, for example 10 MPa or less, for example 9 MPa or less, for example 8 MPa or less, for example 7 MPa or less, for example 6.5 MPa or less, for example 6 MPa or less, for example 5.5 MPa or less, for example 5 MPa or less, for example 4.5 MPa or less, for example 4 MPa or less, for example 3.5 MPa or less, for example 3 MPa or less, for example 2.5 MPa or less. The tensile stress may be determined in accordance with ASTM D412-16 at a temperature of 23°C. In one embodiment, the above tensile stress at break is applicable to a crosslinkable thermoplastic vulcanizate as defined herein. In another embodiment, the above tensile stress at break is applicable to a crosslinked thermoplastic vulcanizate as defined herein.

[0015]

[0018] The thermoplastic vulcanizate may also exhibit a desirable elongation at break (or ultimate elongation). For example, the elongation at break may be 20% or more, such as 40% or more, for example 60% or more, such as 80% or more, for example 100% or more, such as 200% or more, for example 300% or more, such as 400% or more, for example 500% or more, such as 550% or more, for example 600% or more, such as 650% or more, for example 700% or more, such as 750% or more, for example 900% or more, such as 1000% or more, for example 1200% or more, such as 1400% or more, or for example 1600% or more. The elongation at break may be 2000% or less, such as 1800% or less, for example 1600% or less, for example 1500% or less, for example 1300% or less, such as 1000% or less, for example 900% or less, such as 800% or less, for example 700% or less, such as 600% or less, for example 500% or less, such as 450% or less, for example 400% or less, for example 350% or less, such as 300% or less, for example 200% or less, for example 100% or less, such as 80% or less, for example 60% or less. The elongation at break may be determined in accordance with ASTM D412-16 at a temperature of 23°C. In one embodiment, the above elongation at break is applicable to crosslinkable thermoplastic vulcanizates as defined herein. In another embodiment, the above elongation at break is applicable to crosslinked thermoplastic vulcanizates as defined herein.

[0016]

[0019] The thermoplastic vulcanizate may also exhibit a desirable tensile set. For example, the tensile set may be 3% or more, such as 4% or more, such as 5% or more, such as 6% or more, such as 7% or more, such as 8% or more, such as 9% or more, such as 10% or more, such as 11% or more, such as 12% or more, such as 13% or more, or such as 15% or more. The tensile set may be 30% or less, such as 28% or less, such as 25% or less, such as 23% or less, such as 20% or less, such as 18% or less, such as 15% or less, such as 13% or less, such as 10% or less, or such as 8% or less. The tensile set may be determined in accordance with ISO 2285:2019. In one embodiment, the above tensile set may apply to a crosslinkable thermoplastic vulcanizate as defined herein. In another embodiment, the above tensile set may apply to a crosslinked thermoplastic vulcanizate as defined herein.

[0017]

[0020] Various embodiments of the present disclosure will now be described in more detail. I. Thermoplastic vulcanizates

[0021] As described above, a thermoplastic vulcanizate contains an ethylene polymer and an at least partially cured elastomer. In this regard, the thermoplastic vulcanizate may be a crosslinkable thermoplastic vulcanizate in one embodiment. As defined herein, such a crosslinkable thermoplastic vulcanizate comprises a crosslinkable ethylene polymer, and in particular an at least partially cured elastomer dispersed in the crosslinkable ethylene polymer. Thus, as defined herein, such a crosslinkable ethylene polymer has not yet undergone a crosslinking step. In other words, such a crosslinkable ethylene polymer may be an uncrosslinked ethylene polymer. Upon crosslinking, the crosslinkable thermoplastic vulcanizate is converted into a crosslinked thermoplastic vulcanizate, since the crosslinkable ethylene polymer is converted into a crosslinked ethylene polymer. In this regard, a crosslinked thermoplastic vulcanizate may comprise a crosslinked ethylene polymer, and in particular an at least partially cured elastomer dispersed in the crosslinked ethylene polymer.

[0018] A. Ethylene polymer

[0022] As described above, the thermoplastic vulcanizate contains one or more ethylene polymers. In one embodiment, one ethylene polymer may be used in the thermoplastic vulcanizate. In another embodiment, the thermoplastic vulcanizate may include a mixture of ethylene polymers. For example, two or more ethylene polymers, for example, two or three ethylene polymers, may be used in the thermoplastic vulcanizate. Furthermore, the ethylene polymer may be a homopolymer or a copolymer. In one embodiment, the ethylene polymer may be a homopolymer (i.e., a polyethylene homopolymer). In another embodiment, the ethylene polymer may be a copolymer (i.e., a polyethylene copolymer). In a further embodiment, the ethylene polymer may include a mixture of a homopolymer and a copolymer.

[0019]

[0023] In this regard, an ethylene polymer that is a homopolymer can be formed by polymerizing ethylene. When the ethylene polymer is a copolymer, the copolymer is formed by polymerizing ethylene and one or more alpha-olefins, such as one or more C-C 20 Alpha-olefins, such as one or more C3-C 12The copolymer may be formed by polymerizing alpha-olefins, such as one or more C3-C8 alpha-olefins. These alpha-olefins may include, but are not limited to, propylene, 1-butene, 1-hexene, 1-octene, 2-methyl-1-propene, 3-methyl-1-pentene, 4-methyl-1-pentene, 5-methyl-1-hexene, and mixtures thereof. In particular, the alpha-olefin may be propylene, 1-butene, 1-hexene, 1-octene, or mixtures thereof. In one embodiment, the additional monomer may include propylene. In another embodiment, the additional monomer may include 1-butene. In a further embodiment, the additional monomer may include 1-hexene. In yet a further embodiment, the additional monomer may include 1-octene. Furthermore, the additional comonomer may be linear or branched.

[0020]

[0024] In this regard, the ethylene polymer may, in one embodiment, be a copolymer formed from ethylene and propylene. In another embodiment, the ethylene polymer may be a copolymer formed from ethylene and C4-C6 20 Alpha-olefins, e.g., C4-C 12The ethylene polymer may be a copolymer formed from an alpha-olefin, such as a C4 to C8 alpha-olefin. For example, the alpha-olefin may include, but is not limited to, 1-butene, 1-hexene, 1-octene, 2-methyl-1-propene, 3-methyl-1-pentene, 4-methyl-1-pentene, 5-methyl-1-hexene, or a mixture thereof. In this regard, the alpha-olefin may include 1-butene, 1-hexene, 1-octene, or a mixture thereof. In one embodiment, the ethylene polymer may be a copolymer formed from ethylene and at least one of 1-hexene and / or 1-butene. As an example, the ethylene polymer may be a copolymer formed from ethylene and 1-hexene. In another embodiment, the ethylene polymer may be a copolymer formed from ethylene and 1-butene. In a further embodiment, the ethylene polymer may be a copolymer formed from ethylene, propylene, and a C4 to C8 alpha-olefin, such as 1-butene, 1-hexene, 1-octene, 2-methyl-1-propene, 3-methyl-1-pentene, 4-methyl-1-pentene, 5-methyl-1-hexene, or a mixture thereof.

[0021]

[0025] Ethylene copolymers can also be formed by polymerizing ethylene with monomers other than alpha-olefins. For example, in one embodiment, an ethylene copolymer can be formed from ethylene and styrene to provide a styrene-ethylene copolymer. In another embodiment, an ethylene copolymer can be formed from ethylene and one or more α,β-unsaturated acids and / or one or more α,β-unsaturated esters. An example of such an ethylene copolymer can include a polyethylene-acrylate copolymer. In this regard, suitable comonomers may include polar vinyl monomers such as acrylic acid and / or its salts (e.g., inorganic, such as sodium, potassium, lithium, calcium, magnesium, aluminum, copper, nickel, iron, etc.; organic, such as ammonium, monoalkylammonium, dialkylammonium, trialkylammonium, or tetraalkylammonium; or combinations thereof), alkacrylic acid (e.g., methacrylic acid, ethacrylic acid, etc.) and / or its salts, alkyl acrylates (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, etc.), alkacrylates (e.g., methacrylate, ethacrylate, etc.), alkyl alkacrylates (e.g., methyl methacrylate, ethyl methacrylate, methyl isobutyl acrylate, etc.), vinyl acetate, anhydrides (e.g., maleic anhydride, crotonic anhydride, etc.), and the like, as well as combinations thereof.

[0022]

[0026] However, it should be understood that when the ethylene polymer is a copolymer, the first monomer is ethylene. Thus, the ethylene content of the polymer may be greater than 50 mol%, for example, 55 mol% or more, for example, 60 mol% or more, for example, 65 mol% or more, for example, 70 mol% or more, for example, 75 mol% or more, for example, 80 mol% or more, for example, 85 mol% or more, for example, 90 mol% or more, for example, 95 mol% or more, to less than 100 mol%, for example, 99 mol% or less, for example, 98 mol% or less, for example, 97 mol% or less, for example, 96 mol% or less, for example, 95 mol% or less. Meanwhile, the comonomer, for example, C3-C6 20 The alpha-olefin can be present in an amount of less than 50 mol%, for example, 40 mol% or less, for example, 30 mol% or less, for example, 25 mol% or less, for example, 20 mol% or less, for example, 15 mol% or less, for example, 10 mol% or less, for example, 5 mol% or less, to more than 0 mol%, for example, 1 mol% or more, for example, 2 mol% or more, for example, 3 mol% or more, for example, 4 mol% or more, for example, 5 mol% or more. In particular, the propylene content of the polymer can be 20 mol% or less, for example, 15 mol% or less, for example, 10 mol% or less, for example, 5 mol% or less, for example, 3 mol% or less, for example, 2 mol% or less, for example, 1 mol% or less, for example, about 0 mol%. The propylene content can be 0 mol% or more, for example, 0.01 mol% or more, for example, 0.05 mol% or more, for example, 0.1 mol% or more. In a particular embodiment, the ethylene polymer cannot be formed from any propylene.

[0023]

[0027] In addition to the above, in one embodiment, the ethylene polymer can have a particular density. For example, the density can be about 0.80 g / cm. 3 ~Approx. 1g / cm 3 , for example, about 0.84 g / cm 3 ~approx. 0.99g / cm 3 , for example, about 0.84 g / cm 3 ~Approx. 0.94g / cm 3 , for example, about 0.85 g / cm 3 ~Approx. 0.94g / cm 3 , for example, about 0.91 g / cm 3 ~Approx. 0.94g / cm 3In this regard, the ethylene polymer may be linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), or a mixture thereof. Such polyethylene may have a specific density as determined in accordance with ASTM D792. For example, linear low density polyethylene (LLDPE) has a density of about 0.91 g / cm. 3 ~Approx. 0.94g / cm 3 Low density polyethylene (LDPE) can have a density in the range of about 0.91 g / cm 3 ~Approx. 0.925g / cm 3 Medium density polyethylene (MDPE) has a density of about 0.926 g / cm 3 ~Approx. 0.94g / cm 3 and high density polyethylene (HDPE) has a density of about 0.941 g / cm 3 ~Approx. 0.965g / cm 3 In one embodiment, the ethylene polymer may be a low density polyethylene. In another embodiment, the ethylene polymer may be a linear low density polyethylene. In a further embodiment, the ethylene polymer may be a medium density polyethylene.

[0024]

[0028] In one embodiment, the ethylene polymer may be a low-density polyethylene copolymer formed from ethylene and 1-butene. In another embodiment, the ethylene polymer may be a linear low-density polyethylene copolymer formed from ethylene and 1-butene. In a further embodiment, the ethylene polymer may be a medium-density polyethylene copolymer formed from ethylene and 1-butene.

[0025]

[0029] In one embodiment, the ethylene polymer may be a low-density polyethylene copolymer formed from ethylene and 1-hexene. In another further embodiment, the ethylene polymer may be a linear low-density polyethylene copolymer formed from ethylene and 1-hexene. In a further embodiment, the ethylene polymer may be a medium-density polyethylene copolymer formed from ethylene and 1-hexene.

[0026]

[0030] In one embodiment, the ethylene polymer can also include a functionalized ethylene polymer. In one embodiment, the functionalized ethylene polymer may be present as the first ethylene polymer. In another embodiment, the functionalized ethylene polymer may be present as the second ethylene polymer, for example, in a lesser amount than another ethylene polymer in the thermoplastic vulcanizate.

[0027]

[0031] Functional ethylene polymers can include polymers containing at least one functional group. The functional group, which may also be referred to as a functional substituent or functional moiety, contains a heteroatom. In one or more embodiments, the functional group includes a polar group. Examples of polar groups include hydroxyl, carbonyl, ether, halide, amine, imine, nitrile, silyl, epoxide, or isocyanate groups. Exemplary groups containing a carbonyl moiety include carboxylic acid, anhydride, ketone, acid halide, ester, amide, or imide groups, and derivatives thereof. In one embodiment, the functional group includes a succinic anhydride group or the corresponding acid, which may be derived from reaction (e.g., polymerization or grafting) with maleic anhydride or β-alkyl-substituted propanoic acid groups, or derivatives thereof.

[0028]

[0032] Generally, ethylene polymers can comprise solid, generally high molecular weight polymeric materials. The ethylene polymers can have a Mw of about 50,000 g / mol or more, such as 75,000 g / mol or more, for example 100,000 g / mol or more, for example 200,000 g / mol or more, for example 300,000 g / mol or more, for example 400,000 g / mol or more, for example 500,000 g / mol or more, for example 750,000 g / mol or more, for example 1,000,000 g / mol or more, for example 2,000,000 g / mol or more, for example 3,000,000 g / mol or more. The Mw may be about 6,000,000 g / mol or less, such as about 5,000,000 g / mol or less, for example, 4,000,000 g / mol or less, such as 3,000,000 g / mol or less, for example, 2,000,000 g / mol or less, such as 1,500,000 g / mol or less, for example, 1,000,000 g / mol or less, such as 900,000 g / mol or less, for example, 800,000 g / mol or less, for example, 700,000 g / mol or less. Further, the ethylene polymer may have a Mn of about 50,000 g / mol or more, such as 75,000 g / mol or more, for example 100,000 g / mol or more, such as 200,000 g / mol or more, for example 300,000 g / mol or more, such as 400,000 g / mol or more, for example 500,000 g / mol or more, such as 750,000 g / mol or more, for example 1,000,000 g / mol or more, such as 2,000,000 g / mol or more, for example 3,000,000 g / mol or more. Mn may be about 6,000,000 g / mol or less, such as about 5,000,000 g / mol or less, for example, 4,000,000 g / mol or less, for example, 3,000,000 g / mol or less, for example, 2,000,000 g / mol or less, for example, 1,500,000 g / mol or less, for example, 1,000,000 g / mol or less, for example, 900,000 g / mol or less, for example, 800,000 g / mol or less, for example, 700,000 g / mol or less. Generally, molecular weight can be characterized by GPC (gel permeation chromatography) using polystyrene standards.

[0029]

[0033] In one embodiment, the ethylene polymer may be a crystalline polymer, or in another embodiment, a semi-crystalline polymer. For example, the crystallinity may be at least 25% by weight, such as at least 35%, for example at least 45%, for example at least 55%, for example at least 65%, for example at least 70%, for example at least 75%, for example at least 80%, for example at least 85%, for example at least 90%, for example at least 95%. In one embodiment, the crystallinity may be about 100%. The crystallinity may be determined by differential scanning calorimetry. For example, the crystallinity may be determined by dividing the heat of fusion of a sample by the heat of fusion of a 100% crystalline polymer.

[0030]

[0034] The ethylene polymer may also have a particular glass transition temperature ("Tg") In this regard, the Tg may be about -130°C or higher, such as -120°C or higher, for example -110°C or higher, for example -100°C or higher, for example -90°C or higher, for example -70°C or higher, for example -50°C or higher, for example -30°C or higher, for example -25°C or higher, for example -20°C or higher, for example -15°C or higher, for example -10°C or higher, for example -5°C or higher, for example 0°C or higher, for example 5°C or higher, for example 10°C or higher, for example 20°C or higher, for example 30°C or higher, for example 50°C or higher, for example 80°C or higher. The Tg may be about 150°C or less, such as 100°C or less, for example 80°C or less, for example 60°C or less, for example 40°C or less, for example 30°C or less, for example 20°C or less, for example 10°C or less, for example 5°C or less, such as 0°C or less, for example -5°C or less, for example -10°C or less, for example -20°C or less, for example -30°C or less, for example -40°C or less, for example -50°C or less, for example -60°C or less, for example -70°C or less, for example -80°C or less, for example -90°C or less, for example -100°C or less.

[0031]

[0035] In addition, the ethylene polymer may have a particular melting temperature ("Tm"). For example, the melting temperature of the ethylene polymer may be relatively high. Furthermore, the melting temperature of the ethylene polymer may be lower than the decomposition temperature of the elastomer in the thermoplastic vulcanizate, which is generally characterized as when molecular bonds begin to break or cleave, reducing the molecular weight of the elastomer. In this regard, the Tm may be about 30°C or higher, such as 40°C or higher, for example 50°C or higher, for example 60°C or higher, such as 70°C or higher, for example 80°C or higher, for example 90°C or higher, for example 100°C or higher, for example 110°C or higher, for example 120°C or higher, for example 130°C or higher, for example 140°C or higher, for example 150°C or higher. The Tm may be 250° C. or less, such as 200° C. or less, for example 180° C. or less, such as 160° C. or less, for example 150° C. or less, such as 140° C. or less, for example 130° C. or less, such as 120° C. or less, for example 110° C. The melting temperature may be determined by DSC.

[0032]

[0036] The ethylene polymer may also be characterized as having a particular heat of fusion. For example, the heat of fusion may be about 0.1 J / g or more, such as about 1 J / g or more, for example about 2 J / g or more, for example about 5 J / g or more, such as about 10 J / g or more, for example about 10 J / g or more, for example about 30 J / g or more, such as about 40 J / g or more, for example about 50 J / g or more, for example about 60 J / g or more, for example about 70 J / g or more, such as about 100 J / g or more, for example about 120 J / g or more, such as about 140 J / g or more, for example about 160 J / g or more, for example about 180 J / g or more, for example about 200 J / g or more. The heat of fusion may be about 300 J / g or less, such as about 260 J / g or less, for example about 240 J / g or less, for example about 200 J / g or less, such as about 180 J / g or less, for example about 150 J / g or less, such as about 120 J / g or less, for example about 100 J / g or less, such as about 80 J / g or less, for example about 60 J / g or less, for example about 50 J / g or less, such as about 40 J / g or less, for example about 30 J / g or less, for example about 20 J / g or less. The heat of fusion may be determined by DSC.

[0033]

[0037] The ethylene polymer can have a melt flow rate of up to 400 g / 10 min. Generally, an ethylene polymer can have better properties if the melt flow rate is less than about 30 g / 10 min, preferably less than 10 g / 10 min, for example, less than about 2 g / 10 min, for example, less than about 1 g / 10 min, for example, less than about 0.8 g / 10 min. Generally, the melt flow rate can be 0.1 g / 10 min or more, for example, 0.2 g / 10 min or more, for example, 0.3 g / 10 min or more, for example, 0.4 g / 10 min or more, for example, 0.5 g / 10 min or more. The melt flow rate is a measure of how easily a polymer flows under standard pressure and is measured by ASTM D-1238 at 190°C and a load of 2.16 kg.

[0034]

[0038] The ethylene polymer may also have a particular modulus of elasticity, for example, the modulus may be 50 MPa or more, such as 100 MPa or more, for example, 200 MPa or more, for example, 300 MPa or more, for example, 400 MPa or more, for example, 500 MPa or more, for example, 700 MPa or more, for example, 1,000 MPa or more, for example, 1,500 MPa or more, for example, 2,000 MPa or more, for example, 3,000 MPa or more. The elastic modulus may be 5,000 MPa or less, such as 4,500 MPa or less, for example 4,000 MPa or less, for example 3,500 MPa or less, for example 3,000 MPa or less, for example 2,500 MPa or less, for example 2,000 MPa or less, such as 1,500 MPa or less, for example 1,300 MPa or less, for example 1,000 MPa or less, for example 900 MPa or less, for example 800 MPa or less, for example 700 MPa or less, for example 600 MPa or less, for example 500 MPa or less, for example 400 MPa or less, for example 300 MPa or less, for example 200 MPa or less. The elastic modulus may be determined in accordance with ASTM D638-10.

[0035]

[0039] The ethylene polymer may also have a specific 1% secant flexural modulus. For example, the 1% secant flexural modulus may be 50 MPa or more, such as 100 MPa or more, for example 150 MPa or more, for example 200 MPa or more, for example 300 MPa or more, for example 400 MPa or more, for example 500 MPa or more. The 1% secant flexural modulus may be 1,500 MPa or less, for example 1,300 MPa or less, for example 1,000 MPa or less, for example 900 MPa or less, for example 800 MPa or less, for example 700 MPa or less, for example 600 MPa or less, for example 500 MPa or less, for example 400 MPa or less, for example 300 MPa or less, for example 200 MPa or less. The 1% secant flexural modulus may be determined according to ASTM D882-18.

[0036]

[0040] The ethylene polymer may also have a specific tensile strength at break. For example, the ethylene polymer may exhibit a tensile strength at break of 1 MPa or more, for example, 2 MPa or more, for example, 3 MPa or more, for example, 5 MPa or more, for example, 10 MPa or more, for example, 15 MPa or more, for example, 20 MPa or more, for example, 25 MPa or more, for example, 30 MPa or more, for example, 35 MPa or more, for example, 40 MPa or more, for example, 45 MPa or more. The tensile strength at break may be 150 MPa or less, for example, 120 MPa or less, for example, 100 MPa or less, for example, 90 MPa or less, for example, 80 MPa or less, for example, 70 MPa or less, for example, 60 MPa or less, for example, 50 MPa or less, for example, 40 MPa or less. The tensile strength at break may be determined in accordance with ASTM D882-18.

[0037]

[0041] The ethylene polymer may also exhibit a desirable elongation at break (or ultimate elongation). For example, the elongation at break may be 100% or more, such as 200% or more, for example 300% or more, for example 400% or more, for example 500% or more, for example 550% or more, for example 600% or more, for example 650% or more, for example 700% or more, for example 750% or more. The ethylene polymer may be 1500% or less, for example 1300% or less, for example 1000% or less, for example 900% or less, for example 800% or less, for example 700% or less, for example 600% or less, for example 500% or less, for example 450% or less, for example 400% or less, for example 350% or less, for example 300% or less. The elongation at break may be determined in accordance with ASTM D882-18.

[0038]

[0042] The thermoplastic vulcanizate may generally comprise at least about 5 wt. % of the ethylene polymer, such as at least about 10 wt. %, for example at least about 15 wt. %, for example at least about 20 wt. %, for example at least about 25 wt. %, for example at least about 30 wt. %, for example at least about 35 wt. %, for example at least about 40 wt. %, for example at least about 50 wt. %, for example at least about 60 wt. % of the ethylene polymer. The thermoplastic vulcanizate may comprise at most about 90 wt. %, for example at most about 80 wt. %, for example at most about 70 wt. %, for example at most about 60 wt. %, for example at most about 50 wt. %, for example at most about 40 wt. %, for example at most about 30 wt. %, for example at most about 20 wt. %, for example at most about 15 wt. % of the ethylene polymer. In one embodiment, these weight percentages may be based on the weight of the thermoplastic vulcanizate. In another embodiment, these weight percentages may be based on the total weight of the ethylene polymer and the combined elastomer. Furthermore, the thermoplastic vulcanizate may, in one embodiment, be a crosslinkable thermoplastic vulcanizate. In another embodiment, the thermoplastic vulcanizate may refer to a crosslinked thermoplastic vulcanizate.

[0039]

[0043] In other words, the ethylene polymer can be present in an amount of 10 phr or more, for example, 15 phr or more, for example, 20 phr or more, for example, 25 phr or more, for example, 30 phr or more, for example, 40 phr or more, for example, 50 phr or more, for example, 60 phr or more, for example, 70 phr or more, for example, 80 phr or more. The ethylene polymer can be present in an amount of 200 phr or less, for example, 150 phr or less, for example, 120 phr or less, for example, 100 phr or less, for example, 90 phr or less, for example, 80 phr or less, for example, 70 phr or less, for example, 60 phr or less, for example, 50 phr or less, for example, 40 phr or less, for example, 30 phr or less. In one embodiment, this content of ethylene polymer may refer to a crosslinkable ethylene polymer in a crosslinkable thermoplastic vulcanizate. In another embodiment, this content of ethylene polymer may refer to a crosslinked ethylene polymer in a crosslinked thermoplastic vulcanizate.

[0040]

[0044] Furthermore, the thermoplastic vulcanizate can include 20% by weight or less, e.g., 15% by weight or less, e.g., 10% by weight or less, e.g., 5% by weight or less, e.g., 4% by weight or less, e.g., 3% by weight or less, e.g., 2% by weight or less, e.g., 1% by weight or less, e.g., 0.5% by weight or less, e.g., about 0% by weight of a thermoplastic resin that is a propylene polymer. The propylene polymer may be present in an amount of 0% by weight or more. In one embodiment, the propylene polymer may be present in an amount of about 0% by weight. For clarity, such propylene polymers, generally considered thermoplastics, are distinguished from any elastomeric component defined herein that includes a propylene monomer. This amount of propylene polymer may refer to crosslinkable thermoplastic vulcanizates and / or crosslinked thermoplastic vulcanizates. For example, such propylene polymers may be thermoplastics containing 50% by mole or more, e.g., 60% by mole or more, e.g., 70% by mole or more, e.g., 80% by mole or more, e.g., 85% by mole or more, e.g., 90% by mole or more, e.g., 95% by mole or more, of propylene units.

[0041]

[0045] Furthermore, as used herein, the method for producing ethylene polymers is not limited. For example, ethylene polymers can be synthesized using any polymerization technique known in the art, including, but not limited to, Phillips catalysis, conventional Ziegler-Natta polymerization, and metallocene catalysis, including, but not limited to, metallocene-alumoxane and metallocene-ionic activator catalysis. Accordingly, suitable catalyst systems include chiral metallocene catalyst systems, see, e.g., U.S. Pat. No. 5,441,920, and transition metal-centered heteroaryl ligand catalyst systems, see, e.g., U.S. Pat. No. 6,960,635.

[0042] B. Elastomer

[0046] As noted above, thermoplastic vulcanizates contain an elastomer. Generally, any elastomer suitable for use in producing TPVs can be used in accordance with the present disclosure. In one embodiment, one elastomer can be used as the elastomer. In other embodiments, the elastomer can include a mixture of elastomers. For example, two or more elastomers, such as two or three elastomers, can be used in the thermoplastic vulcanizate.

[0043]

[0047] Any elastomer or mixture thereof that can be vulcanized (crosslinked or cured) can be used as the elastomer (sometimes referred to herein as rubber). Reference to rubber or elastomer can include mixtures of two or more. Some non-limiting examples of these rubbers include polyolefin copolymer elastomers, butyl rubber, natural rubber, styrene-butadiene copolymer rubber (e.g., styrene / ethylene-butadiene / styrene), butadiene rubber, acrylonitrile rubber, halogenated rubbers such as brominated and chlorinated isobutylene-isoprene copolymer rubber, butadiene-styrene-vinylpyridine rubber, urethane rubber, polyisoprene rubber, epichlorohydrin terpolymer rubber, and polychloroprene.

[0044]

[0048] Vulcanizable elastomers include polyolefin copolymer elastomers. These copolymers are made from one or more of ethylene and higher alpha-olefins, including, but not limited to, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, or combinations thereof. An example of such a copolymer elastomer may be ethylene-propylene rubber. Furthermore, in addition to ethylene and higher alpha-olefins, the elastomer may also contain one or more copolymerizable, cross-linked unsaturated comonomers, such as diolefins or diene monomers. The alpha-olefin may be propylene, 1-hexene, 1-octene, or combinations thereof. These rubbers may have little to no substantial crystallinity and may preferably be amorphous copolymers.

[0045]

[0049] The diene monomer may include, but is not limited to, 5-ethylidene-2-norbornene; 1,4-hexadiene; 5-methylene-2-norbornene; 1,6-octadiene; 5-methyl-1,4-hexadiene; 3,7-dimethyl-1,6-octadiene; 1,3-cyclopentadiene; 1,4-cyclohexadiene; dicyclopentadiene; 5-vinyl-2-norbornene, divinylbenzene, etc., or a combination thereof. The diene monomer may be 5-ethylidene-2-norbornene and / or 5-vinyl-2-norbornene. When a copolymer is prepared from ethylene monomer, alpha-olefin monomer, and diene monomer, the copolymer may be referred to as a terpolymer (EPDM rubber), or when multiple alpha-olefins or dienes or both are used, it may be referred to as a tetrapolymer (EAODM rubber).

[0046]

[0050] The elastomer, which is a polyolefin elastomeric copolymer, can contain about 15 to about 90 mole percent, about 40 to about 85 mole percent, or about 50 to about 80 mole percent ethylene units derived from ethylene monomers. The copolymer can contain about 10 to about 85 mole percent, about 15 to about 50 mole percent, or about 20 to about 40 mole percent alpha-olefin units derived from alpha-olefin monomers. The aforementioned mole percents are based on the total moles of monomer units in the polymer. When the copolymer contains diene units, the copolymer can contain 0.1 to about 14 weight percent, about 0.2 to about 13 weight percent, or about 1 to about 12 weight percent of units derived from diene monomers. The weight percent of diene units derived from dienes can be determined according to ASTM D-6047. In some cases, the copolymer contains less than 5.5 weight percent, e.g., less than 5.0 weight percent, e.g., less than 4.5 weight percent, e.g., less than 4.0 weight percent, of units derived from diene monomers. In still other cases, the copolymer contains greater than 6.0 weight percent, such as greater than 6.2 weight percent, such as greater than 6.5 weight percent, such as greater than 7.0 weight percent, such as greater than 8.0 weight percent, of units derived from diene monomers.

[0047]

[0051] Polyolefin elastomeric copolymers can be obtained using polymerization techniques known in the art, such as conventional solution or slurry polymerization methods. For example, catalysts used to polymerize ethylene, alpha-olefin, and diene monomers into elastomeric copolymers can include both conventional Ziegler-Natta catalyst systems, particularly those containing titanium and vanadium compounds, and Group 3-6 (titanium, zirconium, and hafnium) metallocene catalysts, particularly bridged monocyclopentadienyl or biscyclopentadienyl metallocene catalysts. Other catalyst systems, such as Brookhart catalyst systems, can also be used.

[0048]

[0052] In one embodiment, the elastomer can include butyl rubber. For example, butyl rubber includes copolymers and terpolymers of isobutylene and at least one other comonomer. Useful comonomers include isoprene, divinylaromatic monomers, alkyl-substituted vinylaromatic monomers, and mixtures thereof. Exemplary divinylaromatic monomers include vinylstyrene. Exemplary alkyl-substituted vinylaromatic monomers include α-methylstyrene and paramethylstyrene. These copolymers and terpolymers can also be halogenated, as in the case of, for example, chlorinated and brominated butyl rubber. In one or more embodiments, these halogenated polymers can be derived from monomers such as parabromomethylstyrene.

[0049]

[0053] In one or more embodiments, butyl rubber includes copolymers of isobutylene and isoprene, copolymers of isobutylene and paramethylstyrene, terpolymers of isobutylene, isoprene, and divinylstyrene, branched butyl rubber, and brominated copolymers of isobutene and paramethylstyrene (resulting in copolymers containing parabromomethylstyrenyl monomer units). These copolymers and terpolymers may also be halogenated. Additionally, butyl rubber may be prepared using techniques known in the art, such as by polymerization at low temperatures in the presence of Friedel-Crafts catalysts.

[0050]

[0054] In one embodiment, when the butyl rubber comprises an isobutylene-isoprene copolymer, the copolymer may comprise from about 0.5 to about 30 weight percent, or from about 0.8 to about 5 weight percent, of isoprene, based on the total weight of the copolymer, with the remainder being isobutylene.

[0051]

[0055] In another embodiment, when the butyl rubber comprises an isobutylene-paramethylstyrene copolymer, the copolymer may contain from about 0.5 to about 25 weight percent, from about 2 to about 20 weight percent, of paramethylstyrene, based on the total weight of the copolymer, with the remainder being isobutylene. In one embodiment, the isobutylene-paramethylstyrene copolymer may be halogenated, for example with bromine, and these halogenated copolymers may contain from about 0 to about 10 weight percent, or from about 0.3 to about 7 weight percent halogenation.

[0052]

[0056] In other embodiments, when the butyl rubber comprises isobutylene-isoprene-divinylstyrene, the terpolymer can comprise from about 95 to about 99 weight percent, or from about 96 to about 98.5 weight percent, of isobutylene, from about 0.5 to about 5 weight percent, or from about 0.8 to about 2.5 weight percent, of isoprene, with the remainder being divinylstyrene, based on the total weight of the terpolymer.

[0053]

[0057] In the case of halogenated butyl rubber, the butyl rubber can contain from about 0.1 to about 10 weight percent, or from about 0.3 to about 7 weight percent, or from about 0.5 to about 3 weight percent halogen, based on the total weight of the copolymer or terpolymer.

[0054]

[0058] In one or more embodiments, the glass transition temperature (Tg) of the butyl rubber may be less than about −55° C., or less than about −58° C., or less than about −60° C., or less than about −63° C. Additionally, the Mooney viscosity (ML 1+8 @125°C) may be about 25 to about 75, or about 30 to about 60, or about 40 to about 55.

[0055]

[0059] Generally, the elastomer, particularly the polyolefin elastomeric copolymer, may have a Mw of about 50,000 g / mol or more, such as 75,000 g / mol or more, for example 100,000 g / mol or more, such as 200,000 g / mol or more, for example 300,000 g / mol or more, such as 400,000 g / mol or more, for example 500,000 g / mol or more, such as 750,000 g / mol or more, for example 1,000,000 g / mol or more. The Mw may be about 3,000,000 g / mol or less, such as 2,000,000 g / mol or less, for example 1,500,000 g / mol or less, such as 1,000,000 g / mol or less, for example 900,000 g / mol or less, such as 800,000 g / mol or less, for example 700,000 g / mol or less, such as 600,000 g / mol or less, for example 500,000 g / mol or less, such as 400,000 g / mol or less, for example 300,000 g / mol or less. Further, the elastomer, particularly the polyolefin elastomeric copolymer, may have a Mn of about 50,000 g / mol or more, such as 75,000 g / mol or more, for example 100,000 g / mol or more, such as 200,000 g / mol or more, for example 300,000 g / mol or more, such as 400,000 g / mol or more, for example 500,000 g / mol or more, such as 750,000 g / mol or more, for example 1,000,000 g / mol or more. Mn may be about 3,000,000 g / mol or less, such as 2,000,000 g / mol or less, for example 1,500,000 g / mol or less, for example 1,000,000 g / mol or less, for example 900,000 g / mol or less, for example 800,000 g / mol or less, for example 700,000 g / mol or less, for example 600,000 g / mol or less, for example 500,000 g / mol or less, for example 400,000 g / mol or less, for example 300,000 g / mol or less. Generally, molecular weight can be characterized by GPC (gel permeation chromatography) using polystyrene standards.

[0056]

[0060] The thermoplastic vulcanizate generally can contain at least about 2 wt. % elastomer, such as at least about 5 wt. %, for example at least about 10 wt. %, for example at least about 15 wt. %, for example at least about 20 wt. %, for example at least about 25 wt. %, for example at least about 30 wt. %, for example at least about 40 wt. %, for example at least about 50 wt. % elastomer. The thermoplastic vulcanizate can contain at most about 90 wt. % elastomer, for example at most about 80 wt. %, for example at most about 70 wt. %, for example at most about 60 wt. %, for example at most about 50 wt. %, for example at most about 40 wt. %, for example at most about 35 wt. %, for example at most about 30 wt. %, for example at most about 25 wt. %, for example at most about 20 wt. %, for example at most about 15 wt. % elastomer. In another embodiment, the weight percentages recited above may be based on the total weight of the ethylene polymer and the combined elastomer in the thermoplastic vulcanizate.

[0057]

[0061] Furthermore, when a blend of elastomers is present, the first elastomer can be present in an amount of about 60% or more, such as about 70% or more, such as about 80% or more, such as about 90% or more to less than 100% by weight, based on the weight of the elastomer, and the second elastomer can be present in an amount of 40% or less, such as 30% or less, such as 20% or less, such as 15% or less, such as 10% or less, such as 5% or more to greater than 0% by weight of the elastomer.

[0058] C. Cured composition

[0062] As described herein, TPV formulations, particularly elastomers in the formulations, can undergo dynamic vulcanization, resulting in at least partial curing of the elastomer. Generally, any curative capable of curing or crosslinking the elastomer can be used. Some non-limiting examples of these curatives include phenolic resins, peroxides, maleimides, and silicon-containing curatives. In a particular embodiment, the curative can include a phenolic resin, a maleimide, and / or a silicon-containing curative. In a further embodiment, the curative can include a phenolic resin and / or a silicon-containing curative. In this regard, in one embodiment, vulcanization can be carried out without the use of any peroxides. For example, this allows for dynamic vulcanization of the rubber without crosslinking the ethylene polymer.

[0059]

[0063] The curing agent may be used with one or more co-agents to improve the overall state of cure of the elastomer, acting as initiators, catalysts, etc. For example, the curing composition of some embodiments includes one or both of zinc oxide (ZnO) and stannous chloride (SnCl).

[0060]

[0064] Generally, phenolic resins are not necessarily limited. For example, they can include resole resins produced by condensation of alkyl-substituted or unsubstituted phenols with an aldehyde, such as formaldehyde, in an alkaline medium, or by condensation of a difunctional phenol dialcohol. The alkyl substituent of the alkyl-substituted phenol typically contains 1 to about 10 carbon atoms. Dimethylolphenol or phenolic resins substituted in the para position with an alkyl group containing 1 to about 10 carbon atoms can be used. These phenolic curing agents can be thermosetting resins and can also be referred to as phenolic resin curing agents or phenolic resins. Ideally, these phenolic resins can be used in conjunction with a catalyst system. For example, non-halogenated phenolic curing resins are used in conjunction with a halogen donor and, optionally, a hydrogen halide scavenger. If the phenolic curing resin is halogenated, a halogen donor is not required, but a hydrogen halide scavenger, such as ZnO, can be used.

[0061]

[0065] Peroxide curing agent is generally selected from organic peroxides.Examples of organic peroxides include but are not limited to di-tert-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, alpha,alpha-bis(tert-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane, benzoyl peroxide, lauroyl peroxide, dilauroyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, and mixtures thereof.Also, diaryl peroxide, ketone peroxide, peroxydicarbonate, peroxyester, dialkyl peroxide, hydroperoxide, peroxyketal, and mixtures thereof can be used.

[0062]

[0066] As noted above, in one embodiment, the elastomer may not be cured with a peroxide curative. In this regard, the peroxide curative may be present in the TPV formulation in an amount of 0.5 wt.% or less, such as 0.2 wt.% or less, such as 0.1 wt.% or less, such as about 0 wt.%. In other words, the peroxide curative may be present in an amount of 2 phr or less, such as 1 phr or less, such as 0.5 phr or less, such as 0.1 phr or less, such as about 0 phr.

[0063]

[0067] However, in another embodiment, the curing agent may be a peroxide curing agent. As shown below, peroxides may also be used to crosslink ethylene polymers. In this regard, thermoplastic formulations may include a curing agent (e.g., for elastomers) and a crosslinking agent (e.g., for ethylene polymers) in certain embodiments. In such embodiments, a peroxide may be provided, which acts as both a crosslinking agent and a curing agent. In one embodiment, the peroxide may be the same type of peroxide for both functions. In another embodiment, different peroxides may be used, such as a first peroxide and a second peroxide.

[0064]

[0068] Silicon-containing curing agents generally contain silicon hydride compounds having at least two SiH groups. These compounds react with the carbon-carbon double bonds of unsaturated polymers in the presence of a hydrosilylation catalyst. Silicon hydride compounds include, but are not limited to, methylhydrogen polysiloxanes, methylhydrogen dimethyl-siloxane copolymers, alkylmethyl polysiloxanes, bis(dimethylsilyl) alkanes, bis(dimethylsilyl) benzenes, and mixtures thereof.

[0065]

[0069] As noted above, hydrosilylation curing can be carried out in the presence of a catalyst. These catalysts can include, but are not limited to, peroxide catalysts and catalysts containing Group VIII transition metals. These metals include, but are not limited to, palladium, rhodium, and platinum, and complexes of these metals.

[0066]

[0070] In certain embodiments, the curing composition also includes one or both of ZnO and SnCl. In one embodiment, the curing composition can include zinc oxide. In another embodiment, the curing composition can include stannous chloride. In a further embodiment, the curing composition can include zinc oxide and stannous chloride.

[0067]

[0071] A co-agent can also be used with the curing agent. The co-agent can include a multifunctional acrylate ester, a multifunctional methacrylate ester, or a combination thereof. In other words, the co-agent includes two or more organic acrylate or methacrylate substituents. Examples of multi-functional acrylates include diethylene glycol diacrylate, trimethylolpropane triacrylate (TMPTA), ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, propoxylated glycerol triacrylate, pentaerythritol triacrylate, bistrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, ethoxylated pentaerythritol triacrylate, cyclohexanedimethanol diacrylate, ditrimethylolpropane tetraacrylate, or a combination thereof. Examples of multifunctional methacrylates include trimethylolpropane trimethacrylate (TMPTMA), ethylene glycol dimethacrylate, butanediol dimethacrylate, butylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, allyl methacrylate, or a combination thereof. The co-agent may also include triallyl cyanurate, triallyl isocyanurate, triallyl phosphate, sulfur, N-phenyl-bis-maleamide, zinc diacrylate, zinc dimethacrylate, divinylbenzene, 1,2-polybutadiene, trimethylolpropane trimethacrylate, tetramethylene glycol diacrylate, trifunctional acrylic esters, dipentaerythritol pentaacrylate, multifunctional acrylates, retarded cyclohexanedimethanol diacrylate esters, multifunctional methacrylates, acrylate and methacrylate metal salts, oximers such as quinone dioximes, etc.

[0068]

[0072] Additionally, oils can be used in the hardening system. Oils can also be referred to as process oils, extender oils, or plasticizers. Useful oils include mineral oils, synthetic processing oils, or combinations thereof, and can act as plasticizers. Plasticizers include, but are not limited to, aromatic oils, naphthenic oils, and extender oils. Exemplary synthetic processing oils include low molecular weight polylinear alpha-olefins and polybranched alpha-olefins. Suitable esters include monomeric and oligomeric materials having an average molecular weight of less than about 2,000 g / mol, or less than about 600 g / mol. Specific examples include aliphatic monoesters or diesters, or alternatively, oligomeric aliphatic esters or alkyl ether esters.

[0069]

[0073] The curing composition may be added at one or more locations, including the feed hopper of a melt-mixing extruder. In some embodiments, the curing agent and any additional co-agents may be added simultaneously to the TPV formulation; in other embodiments, one or more co-agents may be added at a different time than any one or more of the curing agents as the TPV formulation undergoes processing to form the TPV.

[0070]

[0074] Generally, the amount of curative present should be sufficient to at least partially vulcanize the elastomer, and in some embodiments, sufficient to fully vulcanize the elastomer.

[0071] D. Other Additives

[0075] The thermoplastic vulcanizate formulations of some embodiments can optionally further include one or more additives. Suitable additional TPV additives include, but are not limited to, plasticizers, processing oils, fillers, processing aids, acid scavengers, antioxidants, stabilizers, lubricants, antiblocking agents, antistatic agents, waxes, blowing agents, colorants / pigments, flame retardants, and other processing aids and / or the like. In this regard, the resulting thermoplastic vulcanizate can also include one or more of these additives.

[0072]

[0076] Any suitable processing oil may be included in some embodiments. In certain embodiments, the processing oil may be selected from (i) extension oils, i.e., oils present in oil-extended rubbers (such as those present with the elastomer); (ii) free oils, i.e., oils added during the vulcanization process (separate from any other TPV formulation components, such as the elastomer and thermoplastic vulcanizate); (iii) hardening oils, i.e., oils used to dissolve / disperse curatives, such as curative-in-oil dispersions, e.g., phenolic resins in oil (thus, in such embodiments, the cured composition may be present in the TPV formulation as a curative-in-oil additive); and (iv) any combination of oils (i)-(iii) above. Thus, the processing oil may be present in the TPV formulation as part of another component (e.g., as part of the elastomer when the processing oil is an extending oil and thus the elastomer comprises the elastomer and the extending oil; or as part of the cured composition when the processing oil is a carrier for the curative-in-oil and thus the cured composition comprises the curing oil and the curing agent). Alternatively, the processing oil may be added to the TPV separately from the other ingredients, ie, as free oil.

[0073]

[0077] The extended oil, free oil, and / or hydrogenated oil may be the same or different oils in various embodiments. Process oils can include one or more of (i) "refined" or "mineral" oils, and (ii) synthetic oils. As used herein, mineral oils are oils of lubricating viscosity (i.e., kinematic viscosity 1 mm at 100°C) derived from crude petroleum oils. 2 / sec or greater) that have been subjected to one or more refining and / or hydrotreating steps (e.g., fractionation, hydrocracking, dewaxing, isomerization, and hydrofinishing) to purify and chemically modify the components to achieve a final set of properties. Such "refined" oils are in contrast to "synthetic" oils, which are produced by combining monomer units into larger molecules using catalysts, initiators, and / or heat.

[0074]

[0078] Generally, refined or synthetically processed oils according to some embodiments can include any one or more of, but are not limited to, aromatic oils, naphthenic oils, and paraffinic oils. Exemplary synthetic processing oils are polylinear alpha-olefins, polybranched alpha-olefins, and hydrogenated polyalphaolefins. The compositions of some embodiments of the present invention can include organic esters, alkyl ethers, or combinations thereof.

[0075]

[0079] In certain embodiments, at least a portion of the process oil (e.g., all or a portion of any one or more of the extended oil, free oil, and / or hydrogenated oil) is a low aromatic / sulfur-containing oil, (i) having an aromatic content of less than 5 wt%, or less than 3.5 wt%, or less than 1.5 wt%, based on the weight of the process oil portion; (ii) having a sulfur content of less than 0.3 wt%, or less than 0.003 wt%, based on the weight of the process oil portion. The aromatic content can be determined in the same manner as in the ASTM D2007 method. The percentage of aromatic carbon in some embodiments of the process oil is preferably less than 2%, less than 1%, or less than 0.5%. In certain embodiments, there is no aromatic carbon in the process oil. The aromatic carbon percentage (%) in this specification refers to the percentage of aromatic carbon atoms relative to the total number of carbon atoms, as determined by the method according to ASTM D2140.

[0076]

[0080] Suitable process oils of certain embodiments may include base oils of API Groups I, II, III, IV, and V. See API 1509, Engine Oil Licensing and Certification System, 17th Edition, September 2012, Appx. E, incorporated herein by reference.

[0077]

[0081] The TPV formulations of some embodiments may include, or may instead include, polymer processing additives. The processing additives used in these embodiments are polymer resins with extremely high melt flow indices. These polymer resins include both linear and branched molecules with melt flow rates greater than about 500 dg / min, more preferably greater than about 750 dg / min, even more preferably greater than about 1000 dg / min, even more preferably greater than about 1200 dg / min, and even more preferably greater than about 1500 dg / min. The thermoplastic elastomers of the present disclosure may include mixtures of various branched polymer processing additives or various linear polymer processing additives, as well as mixtures of both linear and branched polymer processing additives. References to polymer processing additives include both linear and branched additives unless otherwise indicated. A preferred linear polymer processing additive is polypropylene homopolymer. A preferred branched polymer processing additive includes diene-modified polypropylene polymer.

[0078]

[0082] In addition, the formulations can also contain reinforcing and / or non-reinforcing fillers. Fillers and extenders that can be used include traditional inorganic, such as calcium carbonate, clay, silica, talc, titanium dioxide, and organic, such as carbon black, as well as organic and inorganic nanoscale fillers.

[0079]

[0083] In certain embodiments, the TPV formulation can include an acid scavenger. These acid scavengers can be added to the thermoplastic vulcanizate after the desired level of cure has been achieved. Preferably, the acid scavenger is added after dynamic vulcanization. Useful acid scavengers include hydrotalcites. Both synthetic and natural hydrotalcites can be used. An exemplary natural hydrotalcite has the chemical formula MgAl(OH) 16 It can be represented by the formula CO3·4H2O. Synthetic hydrotalcite compounds have the formula Mg 4.3Al2(OH) 12 ·6CO3·mH2O or chemical formula Mg 4.5 Al2(OH) 13 It can have CO3·3.5H2O.

[0080]

[0084] These additives may be used in amounts that provide the desired effect. In this regard, the additives may be present in an amount of up to about 50 weight percent of the total TPV formulation or total TPV. In this regard, each additive and / or combination of additives may be present in an amount of 0.001 wt% or more, such as 0.01 wt% or more, for example, 0.05 wt% or more, for example, 0.1 wt% or more, such as 0.2 wt% or more, for example, 0.3 wt% or more, for example, 0.5 wt% or more, such as 1 wt% or more, for example, 2 wt% or more, for example, 3 wt% or more, such as 5 wt% or more, for example, 8 wt% or more, for example, 10 wt% or more, for example, 12 wt% or more, for example, 15 wt% or more, such as 20 wt% or more, for example, 25 wt% or more, for example, 30 wt% or more. They may be present in an amount of 50% by weight or less, such as 40% by weight or less, for example 30% by weight or less, for example 25% by weight or less, for example 20% by weight or less, for example 18% by weight or less, for example 15% by weight or less, for example 13% by weight or less, for example 10% by weight or less, for example 8% by weight or less, for example 6% by weight or less, for example 4% by weight or less, for example 3% by weight or less, for example 2% by weight or less, for example 1% by weight or less, for example 0.5% by weight or less. In another embodiment, these above percentages may be based on the weight of the ethylene polymer. In a further embodiment, these above percentages may be based on the weight of the elastomer. In yet a further embodiment, these above percentages may be based on the combined weight of the ethylene polymer and the elastomer.

[0081] E. TPV formulation

[0085] Generally, as used herein, "TPV formulation" refers to a mixture of components that are blended or accumulated prior to or during processing of the TPV formulation to form a TPV, as defined herein, particularly a crosslinkable TPV and / or crosslinked TPV. It is recognized that components that are mixed together and then processed may or may not be present in the final TPV in the same amounts that were added to the formulation, depending on reactions that occur between some or all of the components during processing of the mixed components.

[0082]

[0086] Generally, TPV formulations according to various embodiments include an elastomer, an ethylene polymer, and a curative (or curing composition), along with any other optional additives. As discussed in more detail below, the TPV formulation undergoes processing, such as dynamic vulcanization, to form the TPV. In certain embodiments, any other additives may be added to the TPV formulation during processing, either before dynamic vulcanization or after dynamic vulcanization.

[0083]

[0087] The relative amounts of the various components in a TPV formulation are conveniently characterized based on the amount of elastomer in the formulation, specifically parts by weight per 100 parts by weight of rubber (phr). In embodiments where the elastomer contains both elastomer and extending oil, as is common with many commercially available elastomers, such as EPDM, the phr amount is based solely on the amount of elastomer, excluding any extending oil present with the elastomer. Thus, as an example, an elastomer containing 100 parts EPDM (rubber) and 75 parts extending oil would actually be considered present in the TPV formulation at 175 phr (i.e., based on 100 parts EPDM rubber). If such a TPV formulation were further characterized as containing 50 phr of ethylene polymer, the formulation would contain 50 parts by weight of ethylene polymer in addition to 100 parts by weight of elastomer and 75 parts by weight of extending oil.

[0084]

[0088] The TPV formulations of some embodiments may include the ethylene polymer in an amount of about 20 to about 300 parts by weight per 100 parts by weight of elastomer or rubber (phr). In various embodiments, the ethylene polymer is present in the TPV formulation in an amount of about 20 phr, about 25 phr, about 30 phr, about 35 phr, about 40 phr, about 45 phr, about 50 phr, about 55 phr, about 60 phr, about 65 phr, about 70 phr, about 75 phr, about 80 phr, about 85 phr, about 90 phr, about 95 phr, about 100 phr, about 105 phr, about 110 phr, about 115 phr, about 120 phr, about 125 phr, about 130 phr, about 135 phr, or the like. The ethylene polymer may be present in an amount ranging from a low of any one of about 140 phr, about 145 phr, about 150 phr, about 165 phr, about 170 phr, and about 175 phr to a high of any one of about 50 phr, about 60 phr, about 70 phr, about 80 phr, about 90 phr, about 100 phr, about 125 phr, about 150 phr, about 175 phr, about 200 phr, about 225 phr, about 250 phr, about 275 phr, and about 300 phr. The ethylene polymer may be present in an amount ranging from any one of the above low values ​​to any one of the above high values, provided that the high value is equal to or greater than the low value. In certain embodiments, increasing amounts of ethylene polymer correspond to increasing hardness of the dynamically vulcanized TPV.

[0085]

[0089] When composed solely of elastomer, the elastomer is by definition present at 100 phr (as per the phr notation). However, in embodiments in which the elastomer component includes components other than elastomer, such as extender oil, the elastomer may be included in the TPV formulation in an amount ranging from a low of any one of about 100.05 phr, about 100.1 phr, about 100.15 phr, about 100.2 phr, about 105 phr, about 110 phr, about 115 phr, and about 120 phr to a high of any one of about 110 phr, about 120 phr, about 125 phr, about 150 phr, about 175 phr, about 200 phr, about 225 phr, and about 250 phr.

[0086]

[0090] As previously mentioned, certain embodiment TPV formulations can optionally include additional TPV additives. The amount of the additional additives is separate and apart from any additives already included in other components of the TPV formulation. For example, any additives, such as extending oils included with the elastomer, are already accounted for as part of the amount of elastomer added to the formulation; therefore, the listed amount of additional additives does not include additives already included with the elastomer. The additional additives may be present in the TPV formulation in an amount ranging from about 0 phr to about 300 phr in total. In certain embodiments, the additional additives may be present in an amount ranging from a lower value of any one of about 0 phr, about 5 phr, about 10 phr, about 15 phr, about 25 phr, about 30 phr, about 40 phr, about 50 phr, about 60 phr, about 70 phr, about 80 phr, about 90 phr, and about 100 phr to a higher value of any one of about 25 phr, about 30 phr, about 40 phr, about 50 phr, about 60 phr, about 80 phr, about 100 phr, about 125 phr, about 150 phr, about 175 phr, about 200 phr, about 225 phr, about 250 phr, about 275 phr, and about 300 phr in total TPV. The additional additives may be included in a total amount ranging from any one of the above lower values ​​to any one of the above higher values, provided that the higher value is equal to or greater than the lower value. In one embodiment, these above phr values ​​may represent the additional additives individually rather than in total.

[0087]

[0091] For convenience, the components of the TPV formulations of various embodiments may alternatively be characterized based on their weight percentages in the TPV formulations below.

[0092] The ethylene polymer(s) may be present in the TPV formulation in an amount from the low of any one of about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24%, and about 25% by weight to about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24% by weight. , about 25 wt%, about 26 wt%, about 27 wt%, about 28 wt%, about 29 wt%, about 30 wt%, about 31 wt%, about 32 wt%, about 33 wt%, about 34 wt%, about 35 wt%, about 36 wt%, about 37 wt%, about 38 wt%, about 39 wt%, about 40 wt%, about 41 wt%, about 42 wt%, about 43 wt%, about 44 wt%, about 45 wt%, about 46 wt%, about 47 wt%, about 48 wt%, about 49 wt%, about 50 wt%, about 51 wt%, about 52 wt%, about 53 wt%, about 54 wt%, about 55 wt%, and about 60 wt%, wherein the higher value is equal to or greater than the lower value.

[0088]

[0093] The elastomer(s) may be present in the TPV formulation at any of about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 25%, about 30%, and about 35% by weight. It can be present in an amount ranging from one low value to any one of about 35 wt%, about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, about 70 wt%, about 75 wt%, and about 80 wt%, provided that the high value is equal to or greater than the low value, and the elastomer(s) are present in the TPV formulation in an amount ranging from about 20 to about 300 phr.

[0089]

[0094] The optional additional TPV additive(s) can be present in the TPV formulation in a total amount ranging from a low of any one of about 0 wt%, about 5 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 35 wt%, and about 40 wt%, to a high of any one of about 30 wt%, about 35 wt%, about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, and about 65 wt%, provided that the high value is equal to or greater than the low value, and the additive(s) are present in the TPV formulation in a range of from about 0 to about 300 phr.

[0090] F. Processing the TPV Formulation

[0095] The thermoplastic vulcanizates of the present disclosure are prepared by dynamic vulcanization techniques. The term "dynamic vulcanization" refers to the process of vulcanization or curing of a TPV formulation containing an elastomer, in which the elastomer is vulcanized under high shear mixing conditions at a temperature above the melting point of the ethylene polymer to produce a thermoplastic vulcanizate. In dynamic vulcanization, the elastomer is simultaneously crosslinked and dispersed as fine particles in the ethylene polymer, although other morphologies, such as bicontinuous morphologies, can exist depending on the degree of cure, the viscosity ratio of the elastomer to the resin, the mixing intensity, the residence time, and the temperature.

[0091]

[0096] In some embodiments, processing can include melt-blending a TPV formulation containing an elastomer, an ethylene polymer, and a curative in a chamber. The chamber can be any suitable vessel for blending the selected compositions under the temperature and shear conditions necessary to form a thermoplastic vulcanizate. In this regard, the chamber can be a mixer, such as a Banbury™ mixer or a Brabender™ mixer, as well as certain types of mixing extruders, such as co-rotating extruders, counter-rotating extruders, and twin-screw extruders, and co-kneaders, such as a Buss® kneader. According to one embodiment, the chamber is an extruder, which can be a single-screw or multi-screw extruder. The term "multi-screw extruder" refers to an extruder having two or more screws, such as twin-screw and triple-screw extruders, with twin-screw or twin-screw extruders being preferred in some embodiments. The extruder screws can have multiple lobes, with two- and three-lobe screws being preferred. It is readily understood that other screw designs can be selected in accordance with the methods of the present disclosure. In some embodiments, dynamic vulcanization can occur during and / or as a result of extrusion. After exiting the mixer, the blend containing the vulcanized rubber and thermoplastic can be ground, chopped, extruded, pelletized, injection molded, or processed by any other desired technique.

[0092]

[0097] Dynamic vulcanization of the elastomer can be carried out to achieve relatively high shear. In certain embodiments, the blending step can be carried out at a temperature not exceeding about 400°C, preferably not exceeding about 300°C, and more preferably not exceeding about 250°C. The minimum temperature at which the melt-blending step is carried out is generally not less than about 130°C, preferably not less than about 150°C, and more particularly greater than about 180°C. The blending time is selected by considering the nature of the compounds used in the TPV formulation and the blending temperature. The time generally varies from about 5 seconds to about 120 minutes, and most often from about 10 seconds to about 30 minutes.

[0093]

[0098] In some embodiments, dynamic vulcanization can include phase inversion. As will be appreciated by those skilled in the art, dynamic vulcanization can begin by including a greater volume fraction of rubber than ethylene polymer. Thus, when the rubber volume fraction is greater than the ethylene polymer volume fraction, the ethylene polymer can exist as a discontinuous phase. As dynamic vulcanization progresses, the viscosity of the rubber increases, and phase inversion occurs during dynamic mixing. In other words, upon phase inversion, the ethylene polymer phase becomes a continuous phase.

[0094]

[0099] In some embodiments, one or more other additives (if present) may be added to the composition after curing and / or phase inversion (e.g., after the dynamic vulcanization portion of processing), although the other additive(s) are preferably present in the TPV formulation when dynamic vulcanization is performed. Additional additives may be included after dynamic vulcanization by using a variety of techniques. In one embodiment, additional additives may be added while the thermoplastic vulcanizate remains in its molten state from the dynamic vulcanization step. For example, additional additives may be added downstream of the point of dynamic vulcanization in a process using continuous processing equipment, such as a single-screw or twin-screw extruder. In other embodiments, the thermoplastic vulcanizate may be "post-processed" or pelletized, and then melted, and additional additives may be added to the molten thermoplastic vulcanizate product. This latter process may be referred to as a "second pass" addition of components.

[0095]

[0100] Despite the fact that the elastomer may be partially or fully cured, thermoplastic vulcanizates may be processed and reprocessed by conventional plastic processing techniques, such as extrusion, injection molding, and compression molding. The elastomer in these thermoplastic elastomers is usually in the form of finely divided, well-dispersed particles of vulcanized or cured rubber within a continuous thermoplastic phase or matrix, although co-continuous morphologies or phase inversions are also possible. In embodiments in which the cured rubber is in the form of finely divided, well-dispersed particles within the thermoplastic medium, the rubber particles may have an average diameter of less than 50 μm, e.g., less than 30 μm, e.g., less than 10 μm, e.g., less than 5 μm, e.g., less than 1 μm. In a preferred embodiment, at least 50%, such as at least 60%, for example at least 75% of the rubber particles may have an average diameter of less than 20 μm, such as less than 18 μm, for example less than 15 μm, such as less than 12 μm, for example less than 10 μm, such as less than 8 μm, for example less than 6 μm, such as less than 5 μm, for example less than 2 μm, for example less than 1 μm.

[0096]

[0101] The resulting thermoplastic vulcanizate can have a desirable density (or specific gravity) that enables the thermoplastic vulcanizate to be used for molding as described herein. In this regard, the density is less than 0.3 g / cm. 3 or more, for example, 0.4 g / cm 3 or more, for example, 0.5 g / cm 3 or more, for example, 0.6 g / cm 3 or more, for example, 0.65 g / cm 3 or more, for example, 0.7 g / cm 3 or more, for example, 0.75 g / cm 3 or more, for example, 0.8 g / cm 3 or more, for example, 0.85 g / cm 3 or more, for example, 0.9 g / cm 3 or more, for example, 0.95 g / cm 3 or more, for example, 1g / cm 3 or more, for example, 1.05 g / cm 3 or more, for example, 1.1 g / cm 3or more, for example, 1.15 g / cm 3 or more, for example, 1.2 g / cm 3 The density may be 2 g / cm or more. 3 For example, 1.8 g / cm 3 For example, 1.6 g / cm 3 For example, 1.4 g / cm 3 For example, 1.3 g / cm 3 For example, 1.2 g / cm 3 For example, 1.1 g / cm 3 For example, 1.0 g / cm 3 For example, 0.95 g / cm 3 Below, for example, 0.90 g / cm 3 Below, for example, 0.7 g / cm 3 Below, for example, 0.6 g / cm 3 For example, 0.55 g / cm 3 It may be the following:

[0097] G. Crosslinkable Ethylene Polymers

[0102] As described herein, a crosslinkable ethylene polymer is used to form the crosslinked ethylene polymer present in the crosslinked thermoplastic vulcanizate. In this regard, the crosslinkable ethylene polymer may be crosslinked using means known in the art. For example, crosslinking may be by irradiation or by chemical crosslinking using a crosslinking agent. In one embodiment, crosslinking may be by irradiation. Suitable means of irradiation include, but are not limited to, electron beam radiation.

[0098]

[0103] In another embodiment, crosslinking can be by chemical crosslinking, which can include crosslinking using peroxides, crosslinking by moisture curing, and other known methods. In one embodiment, crosslinking is achieved using peroxides. In another embodiment, crosslinking is achieved by moisture curing.

[0099]

[0104] Peroxide crosslinking uses organic peroxides. For example, organic peroxides can initiate free radical reactions in ethylene polymers, and the resulting free radicals can abstract hydrogen ions from polymer chains and form covalent bonds between them. Crosslinking preferably occurs in the presence of a free radical initiator, including organic peroxides, organic peresters, and / or azo compounds. Examples of such compounds include benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(peroxybenzoate)hexyne-3,1,4-bis(tert-butylperoxyisopropyl)benzene, lauroyl peroxide, tert-butyl peracetate, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl perbenzoate, tert-butyl perphenylacetate, tert-butyl perisobutyrate, tert-butyl per-sec-octanoate, tert-butyl perpivalate, cumyl perpivalate, and tert-butyl perethylacetate, azoisobutyronitrile, and dimethyl azoisobutyrate. In a specific embodiment, the organic peroxide comprises 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0100]

[0105] In moisture-curing embodiments, copolymers of ethylene and vinylsilane can be reacted with water, usually in the presence of a catalyst, to effect crosslinking. The product is produced in conventional thermoplastic processing equipment and then cured offline by exposing it to moisture. The cure rate depends on the moisture level, temperature, and thickness, and can be accelerated by contact with low-pressure steam or hot water. However, it should be understood that crosslinking under ambient conditions is also possible.

[0101]

[0106] Ethylene polymers can be crosslinked with reactive unsaturated silane compounds. Silane crosslinking methods well known in the art include the commercially available MONOSIL process developed by Maillefer and BICC and the SIOPLAS process developed by Dow Corning. In the SIOPLAS or two-step process, ethylene polymers are first graft-modified with a reactive silane compound and a free-radical initiator, such as dicumyl peroxide, in a compounding mixer or compounding extruder to produce, for example, a silane-grafted ethylene polymer. The silane-grafted ethylene polymer is compounded with a silanol condensation catalyst, melt-extruded into the desired form or shape, and then cured (crosslinked) by heat and / or moisture, for example, in a water bath or steam bath. In warm, humid climates, curing can occur under ambient conditions. In the MONOSIL or one-step process, the ethylene polymer, reactive silane compound, free radical initiator, and silanol condensation catalyst are all fed into an extruder, melt extruded into the desired form or shape, and subsequently cured by heat and / or moisture, similar to the two-step process.

[0102]

[0107] The reactive silane compound used above may be an unsaturated silane compound having one or more hydrolyzable groups. These silanes may include aminosilanes, vinylsilanes, vinylaminosilanes, etc. Typical reactive silane compounds include alkenyl groups, such as vinyl groups, allyl groups, isopropenyl groups, butenyl groups, cyclohexenyl groups, or γ-(meth)acryloxyallyl groups, and hydrolyzable groups, such as hydrocarbyloxy groups, hydrocarbonyloxy groups, or hydrocarbylamino groups. Specific examples of hydrolyzable groups include methoxy groups, ethoxy groups, formyloxy groups, acetoxy groups, propionyloxy groups, and alkylamino groups or acrylamino groups. Examples of such silane compounds include, but are not limited to, vinyltriethoxysilane, vinyl-tris-(beta-methoxyethoxy)silane, vinyltrimethoxysilane, methacryloylpropyltrimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-mercaptopropyltrimethoxysilane, and the like, and mixtures thereof. A preferred reactive silane is vinyltrimethoxysilane.

[0103]

[0108] The amount of silane used is readily determined by one skilled in the art based on processing conditions, the particular silane used, and other well-known factors. Typical amounts of silane compound are from about 0.5 to about 10 parts by weight, for example, from about 0.5 to about 10 parts by weight, per 100 parts by weight of ethylene polymer.

[0104]

[0109] The free radical initiator may be a peroxide or an azo compound that decomposes to form a peroxyl or azyl radical, or may be ionizing radiation. Typical peroxides include, for example, dicumyl peroxide, di-tert-butyl peroxide, t-butyl perbenzoate, benzoyl peroxide, cumene hydroperoxide, t-butyl peroctoate, methyl ethyl ketone peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, lauryl peroxide, and tert-butyl peracetate. A suitable azo compound is azobisisobutyl nitrite. A specific peroxide compound is dicumyl peroxide. Another specific peroxide compound is 2,5-dimethyl-2,5-di(t-butylperoxy)hexane. The amount of free radical initiator can be readily determined by one skilled in the art and is typically about 0.01 to about 0.2 parts by weight per 100 parts by weight of ethylene polymer, for example, about 0.04 to about 0.15 parts by weight per 100 parts by weight of ethylene polymer.

[0105]

[0110] The silanol condensation catalyst may be any compound that promotes the condensation crosslinking reaction, such as organic bases, carboxylic acids, and organometallic compounds, including organotitanates, and complexes or carboxylates of lead, cobalt, iron, nickel, zinc, or tin. Specific catalysts include, for example, dibutyltin dilaurate, dioctyltin maleate, dibutyltin diacetate, dibutyltin dioctoate, dibutyltin didodecanoate, stannous acetate, stannous octoate, lead naphthenate, zinc caprylate, and cobalt naphthenate. A specific tin carboxylate is dibutyltin didodecanoate. The catalyst is used in a catalytically effective amount, which can be easily determined by one skilled in the art. Typical catalyst amounts are about 0.01 to about 0.1 parts by weight per 100 parts by weight of ethylene polymer.

[0106]

[0111] The peroxide-initiated reaction of a reactive silane compound, e.g., vinyltrimethoxysilane, and an ethylene polymer results in a graft polymer having an ethylene polymer backbone structure containing pendant silyl moieties, e.g., ethyltrimethoxysilyl moieties. In the crosslinking reaction, the methoxy groups are hydrolyzed to form methanol and pendant ethyldimethoxysilanolyl groups, which undergo condensation reactions with other ethyldimethoxysilanolyl groups, eliminating water and forming Si-O-Si bonds between the pendant silyl moieties.

[0107]

[0112] The cross-linking agent may be provided with a carrier. For example, the carrier may be a porous polymer, silica, titanium dioxide, carbon black, etc. In one embodiment, the carrier may be silica.

[0108]

[0113] As noted above, crosslinking can be achieved by irradiation. Irradiation crosslinking uses ionizing radiation, for example, from a high-energy electron accelerator. The ethylene polymer can be provided with additives to facilitate the crosslinking process. In either case, once the desired shape is formed, the shape can be cured in-line or off-line by being irradiated, for example, by exposing it to an electron beam. In one embodiment, the formed shape can be captured on a large coil or reel and re-sent through the electron beam machine. Depending on the thickness of the molded part (e.g., a portion of a conduit or a layer wall), repeated runs through the electron beam machine may be required to achieve the desired crosslink density.

[0109]

[0114] Upon crosslinking, the crosslinked ethylene polymer can have a degree of crosslinking of 30% or more, such as 40% or more, for example 50% or more, for example 60% or more, for example 65% or more, for example 70% or more, for example 75% or more, for example 80% or more, for example 85% or more. The degree of crosslinking may be less than 100%, for example 95% or less, for example 93% or less, for example 91% or less, for example 90% or less, for example 89% or less, for example 85% or less, for example 80% or less, for example 75% or less. The degree of crosslinking as measured by gel content may be determined in accordance with ASTM D2765-01.

[0110] H. Crosslinked thermoplastic vulcanizate

[0115] As described herein, crosslinked thermoplastic vulcanizates can be formed. In particular, molded articles can include crosslinked thermoplastic vulcanizates. For example, at least a portion (e.g., wall, thickness, layer) of such molded articles can include crosslinked thermoplastic vulcanizates. In particular, molded articles, such as conduits described below, can include layers formed from crosslinked thermoplastic vulcanizates. The manner in which crosslinked thermoplastic vulcanizates can be formed can vary depending on various factors, such as the method of crosslinking.

[0111]

[0116] In one embodiment, a crosslinked thermoplastic vulcanizate can be formed by preparing a thermoplastic vulcanizate formulation including a crosslinkable ethylene polymer, an elastomer, a curing agent, and a crosslinking agent. In this regard, the components required to crosslink the ethylene polymer and the components required to cure the elastomer can be provided in a single process. In such a process, the elastomer can be at least partially cured. For example, the process can include dynamically vulcanizing the elastomer using a curing agent, thereby providing a crosslinkable thermoplastic vulcanizate, and crosslinking the crosslinkable ethylene polymer to yield a crosslinked ethylene polymer and a crosslinked thermoplastic vulcanizate. Crosslinking can be initiated under appropriate conditions, as described above, depending on the specific crosslinking agent and techniques known in the art. Crosslinking can occur simultaneously with dynamic vulcanization. Alternatively, crosslinking can occur after dynamic vulcanization, or at least after dynamic vulcanization has been initiated.

[0112]

[0117] In one embodiment, a crosslinked thermoplastic vulcanizate can be formed by providing a thermoplastic vulcanizate formulation including a crosslinkable ethylene polymer, an elastomer, and a curing agent. The elastomer can be at least partially cured. For example, the method can include dynamically vulcanizing the elastomer using a curing agent, thereby providing a crosslinkable thermoplastic vulcanizate, and the crosslinkable ethylene polymer can be crosslinked by exposure to irradiation to provide a crosslinked ethylene polymer and a crosslinked thermoplastic vulcanizate. In such an embodiment, irradiation can be provided in-line during the production of the crosslinkable thermoplastic vulcanizate. Alternatively, such irradiation can be provided offline, for example, after the production of the crosslinkable thermoplastic vulcanizate. For example, in this latter situation, the method may simply require crosslinking the crosslinkable ethylene polymer in the crosslinkable thermoplastic vulcanizate by exposure to irradiation to provide a crosslinked ethylene polymer and a crosslinked thermoplastic vulcanizate.

[0113]

[0118] In another embodiment, a crosslinked thermoplastic vulcanizate can be formed by blending a crosslinking agent and a crosslinkable thermoplastic vulcanizate comprising a crosslinkable ethylene polymer and an at least partially cured elastomer. The blending step can be by techniques known in the art, such as a mixer, extruder, etc. In this regard, the extruder can be a single-screw extruder, a twin-screw extruder, etc. Such a blender or extruder can be used as a feed device for the step of producing a molded article as defined herein. The crosslinkable ethylene polymer can then be crosslinked to provide a crosslinked ethylene polymer and a crosslinked thermoplastic vulcanizate. Crosslinking can be initiated under appropriate conditions as described above, depending on the specific crosslinking agent and technique known in the art.

[0114] I. Formation of the Article

[0119] The thermoplastic vulcanizate can be shaped into a molded article. For example, the thermoplastic vulcanizate can be used to form an entire molded article or at least a portion of a molded article. For example, the thermoplastic vulcanizate can be used to form a layer, wall, thickness, or section of the molded article.

[0115]

[0120] Furthermore, molded articles can be formed using any of a variety of techniques known in the art. For example, thermoplastic vulcanizates can be advantageously fabricated using typical molding methods, such as injection molding, extrusion, compression molding, blow molding, rotational molding, thermoforming, overmolding, and the like. Generally, these methods include heating the thermoplastic vulcanizate to a temperature above the melting temperature of the ethylene polymer to form a preform. Using injection molding as an example, the thermoplastic vulcanizate is heated against a mold cavity to form a molded article, and the molded article is cooled to a temperature below the crystallization temperature of the thermoplastic vulcanizate, after which the molded article can be removed from the mold. The mold cavity defines the shape of the molded article. The molded article is cooled within the mold to a temperature below the crystallization temperature of the thermoplastic vulcanizate, and the molded article can then be removed from the mold. Methods can also be used to form molded articles, such as conduits, using extrusion molding. In this regard, the thermoplastic vulcanizate can be extruded as described herein. Upon exiting the extruder, the thermoplastic vulcanizate can be formed or shaped to form a molded article. As an example, a thermoplastic vulcanizate can be formed or shaped to form a layer (e.g., outer sheath) of a conduit, such as a wire or cable. Such a molded article can be formed into the shape of the thermoplastic vulcanizate by using a particular die as the thermoplastic vulcanizate exits the extruder.

[0116]

[0121] Furthermore, when the ethylene polymer herein is crosslinked, the crosslinking can occur entirely while the molded article is being produced, after the molded article is produced, or both. For example, the ethylene polymer can be crosslinked while the thermoplastic vulcanizate is being shaped or formed into a molded article. In another embodiment, the thermoplastic vulcanizate can be shaped or formed into a molded article, after which the ethylene polymer can be crosslinked. In a further embodiment, the thermoplastic vulcanizate can be shaped or formed into a molded article, and the ethylene polymer can be crosslinked during or even after the shaping / forming.

[0117]

[0122] If a crosslinking agent is used, the crosslinking agent may be provided along with the thermoplastic vulcanizate. In another embodiment, the crosslinking agent may be provided in a subsequent step. In this regard, the method may include blending a crosslinkable thermoplastic vulcanizate with the crosslinking agent. The blend may then be processed to form a shape, for example, the shape of a molded article. Thereafter, the method may also include crosslinking the ethylene polymer to form a crosslinked ethylene polymer and a corresponding crosslinked thermoplastic vulcanizate.

[0118]

[0123] The crosslinking agent may be blended by techniques known in the art, such as a mixer, extruder, etc. In this regard, the extruder may be a single-screw extruder, a twin-screw extruder, etc. Such a blender or extruder may be used as a feed device to produce the shaped articles defined herein. In this regard, the shaped articles may be formed in a variety of ways.

[0119]

[0124] For example, in one embodiment, a molded article can be formed by blending a crosslinking agent and a crosslinkable thermoplastic vulcanizate comprising a crosslinkable ethylene polymer and an at least partially cured elastomer to form a first blend. The first blend can be formed into the shape of a molded article. The crosslinkable ethylene polymer can be crosslinked to provide a crosslinked ethylene polymer and a crosslinked thermoplastic vulcanizate. Crosslinking can be initiated under appropriate conditions, as described above, depending on the specific crosslinking agent and techniques known in the art. Crosslinking can occur simultaneously during shaping / forming. Alternatively, crosslinking can occur after shaping / forming. Furthermore, crosslinking can occur both during shaping / forming and after shaping / forming.

[0120]

[0125] In another embodiment, a molded article can be formed by forming a crosslinkable thermoplastic vulcanizate comprising a crosslinkable ethylene polymer and an at least partially cured elastomer into the shape of the molded article. The crosslinkable ethylene polymer can be crosslinked by exposure to irradiation to provide a crosslinked ethylene polymer and a crosslinked thermoplastic vulcanizate. Crosslinking can occur simultaneously during shaping / forming. Alternatively, crosslinking can occur after shaping / forming. Furthermore, crosslinking can occur both during shaping / forming and after shaping / forming. In this regard, irradiation can be provided in-line during the initial production and shaping / forming of the molded article. Alternatively, such irradiation can be provided offline, for example, some time after the initial production and shaping / forming of the molded article.

[0121]

[0126] In another embodiment, a molded article can be formed by providing a thermoplastic vulcanizate formulation including a crosslinkable ethylene polymer, an elastomer, a curative, and a crosslinking agent. The method can include dynamically vulcanizing the elastomer, for example, by using a curative, to form a crosslinkable thermoplastic vulcanizate. The crosslinkable thermoplastic vulcanizate can be formed into the shape of a molded article. The crosslinkable ethylene polymer can be crosslinked to provide a crosslinked ethylene polymer and a crosslinked thermoplastic vulcanizate. Crosslinking can be initiated under appropriate conditions, as described above, depending on the specific crosslinking agent and technique known in the art. Crosslinking can occur simultaneously during shaping / forming. Alternatively, crosslinking can occur after shaping / forming. Furthermore, crosslinking can occur both during shaping / forming and after shaping / forming. Furthermore, crosslinking can occur simultaneously with dynamic vulcanization. Alternatively, crosslinking can occur after dynamic vulcanization, or at least after dynamic vulcanization has begun.

[0122]

[0127] In another embodiment, a molded article can be formed by providing a thermoplastic vulcanizate formulation including a crosslinkable ethylene polymer, an elastomer, and a curative, and dynamically vulcanizing the elastomer with the curative to form a crosslinkable thermoplastic vulcanizate. The crosslinkable thermoplastic vulcanizate can be formed into the shape of a molded article. The crosslinkable ethylene polymer can be crosslinked by exposure to radiation to provide a crosslinked ethylene polymer and a crosslinked thermoplastic vulcanizate.

[0123]

[0128] As noted above, crosslinking can be initiated under appropriate conditions, as described above, depending on the particular crosslinking agent and techniques known in the art. In this regard, in one embodiment where the crosslinking agent comprises a peroxide, it can be blended at a temperature below the decomposition point of the peroxide. Crosslinking can include heating the blend to a temperature above the decomposition point of the peroxide. In another embodiment, crosslinking can include the Engel method, in which the peroxide is introduced and then the blend is forced through a head maintained above the decomposition temperature of the peroxide to form a crosslinked extrudate.

[0124]

[0129] Furthermore, in one embodiment in which the crosslinking agent comprises a silane compound, particularly a moisture-curable silane compound, crosslinking can occur upon exposure to moisture. Moisture exposure can include contact with steam and / or hot water at a temperature above 40°C, or the moisture can be in the form of water at a temperature below 15°C, such as a cold water bath (below 10°C) or ice. In another embodiment, atmospheric moisture or humidity can cure the silane. The silane compound can be introduced as a copolymerized comonomer in a reactor copolymer in an ethylene polymer. The blending step can include introducing a masterbatch containing a moisture-curing catalyst into the blend or formulation. Alternatively, or in addition, the silane compound can be grafted onto the ethylene polymer by reactive extrusion, and the grafted polymer can be mixed with the masterbatch containing the moisture-curing catalyst. In one embodiment, the method can include a one-step process in which the silane compound and crosslinking catalyst are introduced into the blend or formulation in a single extruder. Alternatively, or additionally, the method may involve a two-step process in which the silane compound and the crosslinking catalyst are introduced sequentially into the blend or formulation in separate extrusions.

[0125] II. Application

[0130] Crosslinkable and crosslinked thermoplastic vulcanizates can be used in a variety of applications. For example, thermoplastic vulcanizates can be used in applications that may require high temperature resistance and / or high strength. In this regard, the specific application is not necessarily limited. For example, thermoplastic vulcanizates can be used in molded articles in the automotive industry, construction industry, consumer goods industry, oil field industry, medical industry, etc. In this regard, in one embodiment, the molded article can include an automotive product. In another embodiment, the molded article can include a consumer product. In a further embodiment, the molded article can include a medical device. In another further embodiment, the molded article can include an oil field product.

[0126]

[0131] Molded articles may include weather seals, hoses, belts, gaskets, moldings, boots, elastic fibers, conduits, and similar molded articles. In one embodiment, molded articles may include automotive parts, such as, but not limited to, weather seals, brake components, such as, but not limited to, cups, coupling discs, diaphragm cups, boots, e.g., constant velocity joints and constant velocity rack and pinion joints, tubing, sealing gaskets, hydraulically or pneumatically actuated device components, O-rings, pistons, valves, valve seats, valve guides, and other elastomeric polymer-based components, or elastomeric polymers in combination with other materials, such as metals, plastic composites known to those skilled in the art. Additionally, molded articles may include power transmission belts, such as V-belts, toothed belts with truncated ribs containing woven-face V-belts, polished short fiber reinforced V-belts, or short fiber aggregate V-belts, including molded rubber. Molded articles may include weather seal extrusions for the construction and vehicle manufacturing industries, and for liquid transport hoses (e.g., under the hood of an automobile).

[0127]

[0132] In particular, the thermoplastic vulcanizates may be used to form conduits. The conduits may include at least one layer formed from a thermoplastic vulcanizate, particularly a crosslinked thermoplastic vulcanizate as defined herein. In this regard, conduits may include, but are not necessarily limited to, wire jackets, cable jackets, tubing, pipes, and the like. In this regard, in one embodiment, the conduits may be used to transport gases, liquids, and the like. In another embodiment, the conduits may be wire jackets or cable jackets. In particular, the conduits may be used in automotive, industrial, or oil field applications.

[0128]

[0133] In one particular embodiment, the conduit may be a wire jacket. In this regard, the present disclosure may also be directed to a wire including a wire jacket formed from a crosslinked thermoplastic vulcanizate as defined herein. The wire may also include one or more of a shield, a wrapping, a conductor insulation, and a conductor. For example, the wire jacket may define an internal opening or an internal surface. In this regard, such above-mentioned components may be housed or contained within such an internal opening or within a region defined by the internal surface.

[0129]

[0134] In one particular embodiment, the conduit may be a cable jacket. In this regard, the present disclosure may also be directed to a cable including a cable jacket formed from a crosslinked thermoplastic vulcanizate as defined herein. The cable may also include one or more of a shield, a wrapping, a conductor insulation, and a conductor. For example, the cable jacket may define an interior opening or an interior surface. In this regard, such above-mentioned components may be housed or contained within such an interior opening or within an area defined by the interior surface.

[0130]

[0135] In this regard, when the molded article is a conduit, e.g., a wire or cable jacket, internal components (e.g., shielding, wrapping, conductor insulation, conductor, etc.) may be provided during production of the conduit. For example, the conduit may be formed, e.g., extruded, around such internal components.

[0131]

[0136] By using crosslinked thermoplastic vulcanizates, including crosslinked ethylene polymers, the material can meet the high temperature demands of certain applications while exhibiting the necessary hardness, flexibility, and other mechanical properties.

[0132]

[0137] The following test methods may be used to determine the properties referred to herein. Test Method

[0138] Melting Temperature, Glass Transition Temperature, and Heat of Fusion: Melting temperature ("Tm"), glass transition temperature ("Tg"), and heat of fusion ("Hf") can be determined by differential scanning calorimetry ("DSC") as known in the art using commercially available equipment, such as a TA Instruments Model Q100. Typically, 6-10 mg of a sample stored at room temperature (approximately 23°C) for at least 48 hours is sealed in an aluminum pan and loaded into the instrument at room temperature (approximately 23°C). The sample is equilibrated at 25°C and then cooled to -80°C at a cooling rate of 10°C / min. The sample is held at -80°C for 5 minutes and then heated to 25°C at a heating rate of 10°C / min. The glass transition temperature is measured from this heating cycle ("first heat"). For samples that exhibit multiple peaks, the melting point (or melting temperature) is defined as the peak melting temperature associated with the largest endothermic caloric response in that temperature range from the DSC melting trace. g was measured by heating the sample again from -80°C to 80°C at a rate of 20°C / min ("second heat"). The reported glass transition temperature is the midpoint of the step change as it is heated during the second heating cycle. The area under the DSC curve is used to determine the heat of transition (heat of fusion Hf for melting, or heat of crystallization Hc for crystallization; if the Hf value from melting differs from the Hc value obtained from the heat of crystallization, the value from melting (Tm) is used), which can be used to calculate the crystallinity (also referred to as percent crystallinity). Percent crystallinity (X%) is calculated using the formula: [area under the curve (J / g) / H o (J / g)]*100, where H o is the heat of fusion of the homopolymer of the main monomer component. o The value of is the equilibrium heat of fusion (H o ) is used as the equilibrium heat of fusion (H o ) and 207 J / g (H ) for the heat of fusion of 100% crystalline polypropylene. o) values ​​are taken from Polymer Handbook, 4th Edition, published by John Wiley and Sons, New York, 1999.

[0133]

[0139] Tensile strength values ​​(tensile strength at break, elongation at break) were measured according to ASTM D412-16 (machine direction (“MD”). [Example]

[0134] material

[0140] The following examples were prepared using the following materials:

[0135] [Table 1]

[0136] Example 1

[0141] The following samples were prepared to demonstrate the ability to make thermoplastic vulcanizates using various combinations of elastomers, particularly EPDM, and ethylene polymers, particularly ethylene copolymers.

[0137] [Table 2]

[0138] Example 2

[0142] The following samples were prepared to demonstrate the ability to make thermoplastic vulcanizates using various combinations of elastomers, particularly EPDM, and ethylene polymers, particularly ethylene copolymers with varying ethylene polymer content.

[0139] [Table 3]

[0140]

[0143] As can be seen, increasing the ethylene polymer content results in an increase in certain properties, such as hardness, ultimate tensile strength, and 100% modulus, while the elongation is similar for all of the samples and the tensile set is similar for the samples with higher ethylene polymer content.

[0141] Example 3

[0144] The following samples were prepared to demonstrate the ability to produce thermoplastic vulcanizates using various cure systems. For example, Sample 12 was produced using a phenolic cure system, and Sample 13 was produced using a Si-H cure system.

[0142] [Table 4]

[0143] Example 4

[0145] The following samples were prepared to demonstrate the ability to make thermoplastic vulcanizates using various plasticizers: For example, Sample 14 was made using a paraffin oil plasticizer, and Sample 15 was made using a hydrocarbon resin plasticizer, specifically an alicyclic hydrocarbon resin plasticizer.

[0144] [Table 5]

[0145] Example 5

[0146] The following samples were prepared to demonstrate the ability to produce crosslinked thermoplastic vulcanizates based on ethylene polymers. Additionally, properties were compared for ethylene polymer-based thermoplastic vulcanizates and propylene polymer-based thermoplastic vulcanizates, where the ethylene polymer and propylene polymer were not crosslinked. For example, Samples 16 and 18 represent ethylene polymer-based thermoplastic vulcanizates and propylene polymer-based thermoplastic vulcanizates, respectively, where the ethylene polymer and propylene polymer in the thermoplastic phase were not crosslinked. Meanwhile, Sample 17 represents the thermoplastic vulcanizate of Sample 16 that was subjected to an additional crosslinking step to crosslink the ethylene polymer.

[0146] [Table 6]

[0147] As can be seen, hardness and ultimate tensile strength increased between Samples 16 and 17 due to crosslinking. In addition, but not limited to, elongation may have increased due to potential elongation of the rubber phase, while the 100% modulus was comparable. In this regard, Figure 1 illustrates the dynamic mechanical thermal analysis (DMTA) results of Samples 17 and 18, which represent the thermal stability of the crosslinked thermoplastic vulcanizates at temperatures above the melting temperature of the ethylene polymer.

[0148] Example 6 The following samples were prepared to demonstrate the ability to produce crosslinked thermoplastic vulcanizates based on ethylene polymers, where the formulation components, including ethylene polymer, elastomer, curative, and crosslinker, are provided to produce crosslinked thermoplastic vulcanizates in a one-step process rather than a two-step process. In the following samples, peroxide was used as both the curative and crosslinker.

[0149] [Table 7]

[0150]

[0149] Dynamic mechanical thermal analysis (DMTA) was performed on Sample 18 and compared to a commercially available propylene polymer-based thermoplastic vulcanizate, as can be seen in Figure 2. As shown, Figure 2 depicts the thermal stability of the crosslinked thermoplastic vulcanizate at temperatures above the melting temperature of the ethylene polymer.

[0151]

[0150] These and other modifications and variations of the present disclosure may be practiced by those skilled 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 utilized interchangeably both in whole or in part. Furthermore, those skilled in the art will recognize that the foregoing description is merely illustrative and is not intended to limit the invention as further described in the appended claims.

Claims

1. A molded article comprising a crosslinked thermoplastic vulcanizate comprising a crosslinked ethylene polymer and an at least partially cured elastomer.

2. 10. The molded article of claim 1, wherein the crosslinked ethylene polymer is formed from an ethylene copolymer.

3. The ethylene copolymer is a copolymer of ethylene and C ３ ~C ８ The molded article of claim 2 formed from an alpha-olefin.

4. Said C ３ ~C ８ 4. The molded article of claim 3, wherein the alpha-olefin comprises 1-butene, 1-hexene, 1-octene, or a combination thereof.

5. 10. The molded article of claim 1, wherein the crosslinked ethylene polymer is formed from linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, or a mixture thereof.

6. 10. The molded article of claim 1, wherein the crosslinked ethylene polymer is formed from linear low density polyethylene.

7. 10. The molded article of claim 1, wherein the cross-linked ethylene polymer is formed from low density polyethylene.

8. 10. The molded article of claim 1, wherein the cross-linked ethylene polymer is formed from a medium density polyethylene.

9. 9. The molded article of claim 1, wherein the elastomer comprises ethylene / propylene / non-conjugated diene copolymer rubber (EPDM).

10. 9. The molded article according to any one of claims 1 to 8, wherein the elastomer comprises natural rubber, styrene-butadiene copolymer rubber, butadiene rubber, acrylonitrile rubber, halogenated rubber, butadiene-styrene-vinylpyridine rubber, urethane rubber, polyisoprene rubber, epichlorohydrin terpolymer rubber, polychloroprene, or a mixture thereof.

11. The molded article according to claim 1 , wherein the elastomer comprises butyl rubber.

12. 9. The molded article of claim 1, wherein the elastomer comprises a polyolefin elastomeric copolymer.

13. 13. The molded article of any of claims 1 to 12, wherein the crosslinked thermoplastic vulcanizate comprises from about 10% to about 90% by weight of the at least partially cured elastomer and from about 10% to about 90% by weight of the crosslinked ethylene polymer, the weight percentages being based on the weight of the crosslinked thermoplastic vulcanizate.

14. 14. The molded article according to any one of claims 1 to 13, wherein the elastomer is fully vulcanized.

15. 15. The molded article according to any one of claims 1 to 14, wherein the crosslinked thermoplastic vulcanizate exhibits a Shore A hardness (ISO 868:2003) of 25 to 100.

16. 16. The molded article of any of claims 1 to 15, wherein the crosslinked thermoplastic vulcanizate exhibits a 100% modulus determined according to ASTM D412-16 of 0.3 MPa to 50 MPa.

17. 17. The molded article of any of claims 1 to 16, wherein the crosslinked thermoplastic vulcanizate exhibits a tensile stress at break of 0.5 MPa to 100 MPa as determined according to ASTM D412-16.

18. 18. The molded article of any of claims 1 to 17, wherein the crosslinked thermoplastic vulcanizate exhibits an elongation at break of 20% to 2000% as determined according to ASTM D412-16.

19. 19. The molded article according to any one of claims 1 to 18, which is a wire jacket.

20. 19. The molded article according to any one of claims 1 to 18, which is a cable jacket.

21. 19. A wire comprising the molded article of any one of claims 1 to 18 and one or more of a shield, a wrapping, a conductor insulation, and a conductor.

22. 19. A cable comprising the molded article of any one of claims 1 to 18 and one or more of a shield, a wrapping, a conductor insulation, and a conductor.

23. 10. A method of forming the molded article of claim 1, comprising: blending a crosslinking agent with a crosslinkable thermoplastic vulcanizate comprising a crosslinkable ethylene polymer and the at least partially cured elastomer to form a first blend; forming the first blend into the shape of the molded article; crosslinking the crosslinkable ethylene polymer to obtain the crosslinked ethylene polymer and the crosslinked thermoplastic vulcanizate; A method comprising:

24. 24. The method of claim 23, wherein the cross-linking agent comprises a peroxide.

25. The method of claim 23 , wherein the cross-linking agent comprises a silane compound.

26. 26. The method of any of claims 23-25, wherein the at least partially cured elastomer is formed by dynamic vulcanization with a curing agent comprising a phenolic resin curing agent, a silicon-containing curing agent, a maleimide curing agent, or a mixture thereof.

27. 27. The method of any of claims 23 to 26, wherein the at least partially cured elastomer is formed by dynamic vulcanization with a curative, the curative being peroxide-free.

28. 10. A method of forming the molded article of claim 1, comprising: forming a crosslinkable thermoplastic vulcanizate comprising a crosslinkable ethylene polymer and the at least partially cured elastomer into the shape of the molded article; crosslinking said crosslinkable ethylene polymer by exposure to radiation to obtain said crosslinked ethylene polymer and said crosslinked thermoplastic vulcanizate; A method comprising:

29. 30. The method of claim 29, wherein the at least partially cured elastomer is formed by dynamic vulcanization with a curing agent comprising a phenolic resin curing agent, a silicon-containing curing agent, a maleimide curing agent, or a mixture thereof.

30. 30. The method of claim 28 or claim 29, wherein the at least partially cured elastomer is formed by dynamic vulcanization with a curative, the curative being peroxide-free.

31. 10. A method of forming the molded article of claim 1, comprising: providing a thermoplastic vulcanizate formulation comprising a crosslinkable ethylene polymer, an elastomer, a curative, and a crosslinker; dynamically vulcanizing the elastomer with the curative to form a crosslinkable thermoplastic vulcanizate; forming the crosslinkable thermoplastic vulcanizate into the shape of the molded article; crosslinking the crosslinkable ethylene polymer to obtain the crosslinked ethylene polymer and the crosslinked thermoplastic vulcanizate; A method comprising:

32. 32. The method of claim 31 , wherein the curing agent comprises a phenolic resin curing agent, a peroxide curing agent, a silicon-containing curing agent, a maleimide curing agent, or a mixture thereof.

33. 33. The method of claim 31 or claim 32, wherein the cross-linking agent comprises a peroxide.

34. 33. The method of claim 31 or claim 32, wherein the cross-linking agent comprises a silane compound.

35. 32. The method of claim 31 , wherein the curing agent comprises a first peroxide and the crosslinking agent comprises a second peroxide.

36. 36. The method of claim 35, wherein the first peroxide and the second peroxide are the same.

37. 36. The method of claim 35, wherein the first peroxide and the second peroxide are different.

38. 10. A method of forming the molded article of claim 1, comprising: providing a thermoplastic vulcanizate formulation comprising a crosslinkable ethylene polymer, an elastomer, and a curative; dynamically vulcanizing the elastomer with the curative to form a crosslinkable thermoplastic vulcanizate; forming the crosslinkable thermoplastic vulcanizate into the shape of the molded article; crosslinking said crosslinkable ethylene polymer by exposure to radiation to obtain said crosslinked ethylene polymer and said crosslinked thermoplastic vulcanizate; A method comprising:

39. 39. The method of claim 38, wherein the at least partially cured elastomer is formed by dynamic vulcanization with a curative comprising a phenolic resin curative, a silicon-containing curative, or a mixture thereof.

40. 40. The method of claim 38 or claim 39, wherein the at least partially cured elastomer is formed by dynamic vulcanization with a curative, the curative being peroxide-free.

41. 1. A crosslinkable thermoplastic vulcanizate comprising a crosslinkable ethylene polymer and an at least partially cured elastomer, wherein the crosslinkable ethylene polymer has at least 50 mol% ethylene and 0 to less than 20 mol% propylene and is present in an amount of 15% by weight or more and 60% by weight or less, based on the combined weight of the crosslinkable ethylene polymer and the at least partially cured elastomer, and wherein the crosslinkable thermoplastic vulcanizate comprises 5% by weight or less and 0% by weight of a propylene polymer, based on the weight of the crosslinkable thermoplastic vulcanizate, and the propylene polymer comprises 60 mol% or more propylene units.

42. 42. The crosslinkable thermoplastic vulcanizate of claim 41, wherein said crosslinkable ethylene polymer is an ethylene copolymer.

43. The ethylene copolymer is a copolymer of ethylene and C ３ ~C ８ 43. The crosslinkable thermoplastic vulcanizate of claim 42 formed from an alpha-olefin.

44. Said C ３ ~C ８ 44. The crosslinkable thermoplastic vulcanizate of claim 43, wherein the alpha-olefin comprises 1-butene, 1-hexene, 1-octene, or a combination thereof.

45. 42. The crosslinkable thermoplastic vulcanizate of claim 41, wherein said crosslinkable ethylene polymer is linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, or a mixture thereof.

46. 42. The crosslinkable thermoplastic vulcanizate of claim 41, wherein said crosslinkable ethylene polymer is linear low density polyethylene.

47. 42. The crosslinkable thermoplastic vulcanizate of claim 41, wherein said crosslinkable ethylene polymer is a low density polyethylene.

48. 42. The crosslinkable thermoplastic vulcanizate of claim 41, wherein said crosslinkable ethylene polymer is a medium density polyethylene.

49. 42. The crosslinkable thermoplastic vulcanizate of claim 41, wherein said crosslinkable ethylene polymer is high density polyethylene.

50. 50. The crosslinkable thermoplastic vulcanizate of any of claims 42 to 49, wherein the elastomer comprises natural rubber, styrene-butadiene copolymer rubber, butadiene rubber, acrylonitrile rubber, halogenated rubber, butadiene-styrene-vinylpyridine rubber, urethane rubber, polyisoprene rubber, epichlorohydrin terpolymer rubber, polychloroprene, or mixtures thereof.

51. 50. The crosslinkable thermoplastic vulcanizate according to any of claims 42 to 49, wherein the elastomer comprises butyl rubber.

52. 50. The crosslinkable thermoplastic vulcanizate according to any of claims 42 to 49, wherein the elastomer comprises a polyolefin elastomeric copolymer.

53. 50. The crosslinkable thermoplastic vulcanizate of any of claims 42 to 49, wherein the elastomer comprises ethylene / propylene / non-conjugated diene copolymer rubber (EPDM).

54. 54. The crosslinkable thermoplastic vulcanizate of any of claims 42 to 53, further comprising a crosslinking agent.

55. 55. The crosslinkable thermoplastic vulcanizate of claim 54, wherein the crosslinking agent comprises a peroxide.

56. 55. The crosslinkable thermoplastic vulcanizate of claim 54, wherein the crosslinking agent comprises a silane compound.

57. 57. The crosslinkable thermoplastic vulcanizate according to any of claims 42 to 56, wherein the elastomer is fully vulcanized.

58. 58. The crosslinkable thermoplastic vulcanizate of any of claims 42 to 57, wherein the crosslinkable thermoplastic vulcanizate exhibits a Shore A hardness (ISO 868:2003) of 25 to 100.

59. 59. The crosslinkable thermoplastic vulcanizate of any of claims 42 to 58, wherein the crosslinkable thermoplastic vulcanizate exhibits a 100% modulus determined according to ASTM D412-16ISO of 0.3 MPa to 50 MPa.

60. 60. The crosslinkable thermoplastic vulcanizate of any of claims 42 to 59, wherein the crosslinkable thermoplastic vulcanizate exhibits a tensile stress at break of from 0.5 MPa to 100 MPa as determined according to ASTM D412-16.

61. 61. The crosslinkable thermoplastic vulcanizate of any of claims 42 to 60, wherein the crosslinkable thermoplastic vulcanizate exhibits an elongation at break of from 20% to 2000% as determined according to ASTM D412-16.

62. 1. A crosslinked thermoplastic vulcanizate comprising a crosslinked ethylene polymer and an at least partially cured elastomer, wherein the crosslinked ethylene polymer is formed from an ethylene polymer having at least 50 mole percent ethylene and 0 to less than 20 mole percent propylene.

63. 63. The crosslinked thermoplastic vulcanizate of claim 62, wherein the crosslinked ethylene polymer is present in an amount of 15% by weight or more and 60% by weight or less, based on the combined weight of the crosslinked ethylene polymer and the at least partially cured elastomer.

64. 64. The crosslinked thermoplastic vulcanizate of claim 62 or claim 63, wherein the crosslinked ethylene polymer is formed from an ethylene copolymer.

65. The ethylene copolymer is a copolymer of ethylene and C ３ ~C ８ 65. The crosslinked thermoplastic vulcanizate of claim 64 formed from an alpha-olefin.

66. Said C ３ ~C ８ 66. The crosslinked thermoplastic vulcanizate of claim 65, wherein the alpha-olefin comprises 1-butene, 1-hexene, 1-octene, or a combination thereof.

67. 63. The crosslinked thermoplastic vulcanizate of claim 62, wherein said crosslinked ethylene polymer is formed from linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, or mixtures thereof.

68. 63. The crosslinked thermoplastic vulcanizate of claim 62, wherein said crosslinked ethylene polymer is formed from linear low density polyethylene.

69. 63. The crosslinked thermoplastic vulcanizate of claim 62, wherein said crosslinked ethylene polymer is formed from low density polyethylene.

70. 63. The crosslinked thermoplastic vulcanizate of claim 62, wherein said crosslinked ethylene polymer is formed from a medium density polyethylene.

71. 71. The crosslinked thermoplastic vulcanizate of any of claims 62 to 70, wherein the elastomer comprises natural rubber, styrene-butadiene copolymer rubber, butadiene rubber, acrylonitrile rubber, halogenated rubber, butadiene-styrene-vinylpyridine rubber, urethane rubber, polyisoprene rubber, epichlorohydrin terpolymer rubber, polychloroprene, or mixtures thereof.

72. 71. The crosslinked thermoplastic vulcanizate of any of claims 62 to 70, wherein the elastomer comprises butyl rubber.

73. 71. The crosslinked thermoplastic vulcanizate of any of claims 62 to 70, wherein the elastomer comprises a polyolefin elastomeric copolymer.

74. 71. The crosslinked thermoplastic vulcanizate of any of claims 62 to 70, wherein the elastomer comprises ethylene / propylene / non-conjugated diene copolymer rubber (EPDM).

75. 75. The crosslinked thermoplastic vulcanizate of any of claims 62 to 74, wherein the elastomer is fully vulcanized.

76. 76. The crosslinked thermoplastic vulcanizate of any of claims 62 to 75, wherein the crosslinked thermoplastic vulcanizate exhibits a Shore A hardness (ISO 868:2003) of 25 to 100.

77. 77. The crosslinked thermoplastic vulcanizate of any of claims 62 to 76, wherein the crosslinked thermoplastic vulcanizate exhibits a 100% modulus determined according to ASTM D412-16ISO of 0.3 MPa to 50 MPa.

78. 78. The crosslinked thermoplastic vulcanizate of any of claims 62 to 77, wherein the crosslinked thermoplastic vulcanizate exhibits a tensile stress at break of 0.5 MPa to 100 MPa as determined according to ASTM D412-16.

79. 79. The crosslinked thermoplastic vulcanizate of any of claims 62 to 78, wherein the crosslinked thermoplastic vulcanizate exhibits an elongation at break of 20% to 2000% as determined according to ASTM D412-16.

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