Crosslinked thermoplastic elastomers

Abstract

A cross-linkable thermoplastic polymer blend includes a thermoplastic elastomer including vinyl aromatic monomer units and conjugated diene monomer units; a nitrile rubber; and a cure package. The thermoplastic elastomer is at least partially derived from the conjugated diene monomer. The cure package includes a silane cross-linking agent and an organic peroxide. The cross-linkable thermoplastic polymer blend forms a cross-linked thermoplastic elastomer without the need for a catalyst when extruded or injection molded.

Description

[0001] Priority requirements

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 595,328, filed November 1, 2023, with Agent’s File No. 1202319, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments disclosed in this invention generally relate to peroxide vulcanizable compositions and partially crosslinked polymer systems formed therefrom. Background Technology

[0004] Crosslinked thermoplastic articles can possess desired properties, such as chemical resistance and heat resistance. Conventional methods, such as reactive extrusion, are known for forming crosslinked thermoplastic articles. In reactive extrusion, the thermoplastic polymer is crosslinked in an extruder via silane grafting, and the crosslinked thermoplastic polymer is further formed into an article by conversion methods such as extrusion and / or injection molding. For certain applications in the healthcare, automotive, and electronics sectors, additional steps, time, and materials may be required to achieve the desired crosslink density and heat resistance.

[0005] However, although peroxide curing of conjugated diene rubber is commonly practiced in the rubber industry, this method is a batch process and differs significantly from reactive extrusion methods in extruders or injection molds used in the plastics industry. The high reactivity of conjugated diene rubber with peroxides makes this method difficult to control and can cause the extruder to "stick" or introduce other complications.

[0006] Therefore, alternative methods are needed for forming thermoplastic articles with improved crosslinking density and heat resistance, such as using extrusion processes to effectively cure conjugated diene elastomers. Invention Overview

[0008] Based on the disclosure herein, and without limiting the scope of the invention in any way, in a first aspect of the disclosure (unless otherwise stated, it may be combined with any other aspects listed herein), a peroxide-curable composition comprises a thermoplastic elastomer containing repeating units derived from a conjugated diene monomer, a nitrile rubber, and a vulcanizing package. The thermoplastic elastomer is at least partially derived from the conjugated diene monomer. The vulcanizing package contains a silane crosslinking agent and an organic peroxide. When extruded or injection molded, the peroxide-curable composition forms a crosslinked polymer system without the need for a catalyst (e.g., a moisture-curing catalyst).

[0009] In a second aspect of the present invention (which may be combined with any other aspect listed herein, unless otherwise stated), the crosslinked polymer system comprises a silane-grafted nitrile rubber and a silane-grafted thermoplastic elastomer comprising a styrene-diene copolymer. The silane-grafted nitrile rubber and the silane-grafted thermoplastic elastomer are crosslinked via carbon-carbon bonds.

[0010] In the third aspect, unless otherwise stated, the crosslinked polymer system includes any other crosslinked polymer system listed herein, wherein the number-average molecular weight of the thermoplastic elastomer is from about 30,000 g / mol to about 400,000 g / mol.

[0011] In the fourth aspect, unless otherwise stated, the crosslinked polymer system includes any other crosslinked polymer system listed herein, wherein the thermoplastic elastomer is a triblock copolymer comprising two polystyrene end blocks, and wherein the styrene content of the two polystyrene end blocks in the thermoplastic elastomer is from about 10% by weight to about 50% by weight.

[0012] In the fifth aspect, unless otherwise stated, crosslinked polymer systems include any other crosslinked polymer systems listed herein, wherein styrene-diene copolymers include styrene-butadiene-styrene (SBS) or styrene / isoprene block copolymers (SIS).

[0013] In the sixth aspect, unless otherwise stated, the crosslinked polymer system includes any other crosslinked polymer system listed herein, wherein the styrene-diene copolymer is non-hydrogenated.

[0014] In the seventh aspect, unless otherwise stated, crosslinked polymer systems include any other crosslinked polymer systems listed herein, wherein said crosslinked polymer systems include silane crosslinking.

[0015] In the eighth aspect, unless otherwise stated, the crosslinked polymer system includes any other crosslinked polymer system listed herein, wherein the crosslinked polymer system is a thermoplastic vulcanized rubber.

[0016] In the ninth aspect, unless otherwise stated, crosslinked polymer systems include crosslinked polymer systems of any other aspects listed herein, and further include olefin polymers.

[0017] In the tenth aspect, the peroxide vulcanizable composition includes a thermoplastic elastomer containing vinyl aromatic monomer units and conjugated diene monomer units, nitrile rubber, and a vulcanizing package containing organic peroxides and silanes.

[0018] In the eleventh aspect (which may be combined with any other aspect listed herein unless otherwise stated), the peroxide vulcanizable composition comprises about 25% to about 95% by weight of the thermoplastic elastomer, or about 30% to about 85% by weight of the thermoplastic elastomer, or about 35% to about 75% by weight of the thermoplastic elastomer.

[0019] In aspect 12 (unless otherwise stated, it may be combined with any other aspect listed herein), the peroxide vulcanizable composition comprises about 15% by weight to about 50% by weight of nitrile rubber.

[0020] In aspect thirteen (unless otherwise stated, it may be combined with any other aspect listed herein), the thermoplastic elastomer is selected from styrene-butadiene rubber, styrene-butadiene block copolymers, styrene-isoprene block copolymers, styrene-butadiene-isoprene rubber, styrene-butadiene / isoprene block copolymers, styrene-butadiene-isoprene block copolymers, and combinations thereof.

[0021] In the fourteenth aspect (unless otherwise stated, it may be combined with any other aspect listed herein), the thermoplastic elastomer is a triblock copolymer comprising two polystyrene end blocks, and wherein the styrene content of the two polystyrene end blocks in the thermoplastic elastomer is from about 10% by weight to about 50% by weight.

[0022] In the fifteenth aspect (unless otherwise stated, it may be combined with any other aspect listed herein), the peroxide-curable composition comprises about 0.5% by weight to about 5% by weight of silane.

[0023] In the sixteenth aspect (unless otherwise stated, it may be combined with any other aspect listed herein), the silane includes vinyltrimethoxysilane, vinyltriethoxysilane, or combinations thereof.

[0024] In the seventeenth aspect (unless otherwise stated, it may be combined with any other aspect listed herein), the peroxide-curable composition comprises about 0.05% by weight to about 1% by weight of the organic peroxide.

[0025] In the eighteenth aspect (unless otherwise stated, it may be combined with any other aspect listed herein), the organic peroxide includes peroxyketal peroxide, ditert-alkyl peroxide, or a combination thereof.

[0026] In the nineteenth aspect (unless otherwise stated, it may be combined with any other aspect listed herein), the ditert-alkyl peroxide comprises dicumyl peroxide.

[0027] In the twentieth aspect (which may be combined with any other aspects listed herein unless otherwise stated), the composition further comprises an olefin polymer. In some aspects, the olefin polymer is polypropylene.

[0028] In aspect twenty-one (which may be combined with any other aspects listed herein unless otherwise stated), the composition further comprises oil.

[0029] In a twenty-second aspect, a method for preparing a crosslinked polymer system of any other aspect listed herein is provided, comprising the steps of: preparing a carbon-carbon crosslinked silane-grafted blend by blending a thermoplastic elastomer comprising a styrene-diene copolymer, nitrile rubber, an organic peroxide, and a silane, such that the thermoplastic elastomer and the nitrile rubber comprise carbon-carbon crosslinks and grafted silane portions; and extruding the carbon-carbon crosslinked silane-grafted blend.

[0030] In aspect twenty-three (unless otherwise stated, it may be combined with any other aspect listed herein), the step of blending thermoplastic elastomers, organic peroxides, and silanes is carried out in the absence of a catalyst.

[0031] In aspect twenty-four (unless otherwise stated, it may be combined with any other aspect listed herein), the step of blending the thermoplastic elastomer, the organic peroxide, and the silane is carried out in the absence of moisture.

[0032] Detailed description

[0033] This document discloses crosslinked polymer systems, and more specifically, partially crosslinked polymer systems comprising vulcanized silane-grafted thermoplastic elastomers with carbon-carbon crosslinking. In various aspects, the vulcanized silane-grafted thermoplastic elastomers include thermoplastic elastomers comprising repeating units derived from conjugated diene monomers and nitrile rubber. While this disclosure describes certain aspects of crosslinkable thermoplastic blends in detail, this disclosure is to be considered exemplary and is not intended to be limited to the disclosed aspects.

[0034] The terminology used herein is for illustrative purposes only and should not be construed as limiting the entire disclosure. All references to the singular features or limitations of this disclosure shall include the corresponding plural features or limitations, and vice versa, unless otherwise stated or clearly implied by the context of the reference. Unless otherwise stated, “a,” “an,” “the,” and “at least one” are used interchangeably. Furthermore, as used in the specification and appended claims, the singular forms “a,” “an,” and “the” include their plural forms, unless the context clearly indicates otherwise.

[0035] Within the scope of the use of the terms "comprising" or "including" in the specification or claims, they are intended to be inclusive in a manner similar to how the term "comprising" is interpreted when used as a transition word in the claims. Furthermore, within the scope of the use of the term "or" (e.g., A or B), it is intended to mean "A or B or both." The term "A or B only but not both" will be used when the applicant intends to indicate "only A or B but not both." Therefore, the use of the term "or" herein is inclusive, not exclusive.

[0036] The crosslinkable thermoplastic polymer blends disclosed in this invention may contain, consist of, or substantially consist of the basic components disclosed herein as well as any additional or optional components described herein, or components that may be used in crosslinked thermoplastic elastomer applications.

[0037] Unless otherwise stated, all percentages, parts and ratios used herein are on a "dry" basis, i.e., by weight of the total mixture excluding solvents.

[0038] All ranges and parameters disclosed herein, including but not limited to percentages, fractions, and ratios, should be understood to encompass any and all subranges assumed and included therein, as well as every number between the endpoints. For example, the range “1 to 10” should be considered to include any and all subranges that begin with a minimum value of 1 or greater and end with a maximum value of 10 or less (e.g., 1 to 6.1 or 2.3 to 9.4), and every integer contained within that range (1, 2, 3, 4, 5, 6, 7, 8, 9, and 10). A range herein may be expressed as “about” a particular value and / or “about” another particular value. When expressing such a range, another embodiment includes from one particular value and / or to another particular value. Similarly, when a value is expressed as an approximation using the antecedent “about”, it should be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each range are significant both relative to and independent of the other endpoint.

[0039] Unless otherwise stated, the term "% by weight" as used herein refers to the weight fraction of each component based on the total weight of the peroxide-curable composition.

[0040] The term "number-average molecular weight" as used herein refers to the total weight of a polymer measured using gel permeation chromatography (GPC) and polystyrene standards, divided by the total number of molecules.

[0041] The term “melt flow rate” as used herein refers to the ability of a material melt to flow under pressure, as measured according to ASTM D1238 at a given temperature and weight.

[0042] The term “density” as used in this article refers to the mass of a unit volume of material as measured at 23°C according to ASTM D792.

[0043] The term "specific gravity" as used in this article refers to the ratio of the density of a material to the density of water, as measured at 23°C according to ASTM D792.

[0044] The term “Mounney viscosity” as used herein refers to the viscosity reached by a rotor after being rotated at a specified temperature for a given time interval, as measured according to ASTM D1646.

[0045] The term "yield" as used in this article refers to the point on the stress-strain curve that indicates the limit of elastic behavior and the onset of plastic behavior.

[0046] The term “yield tensile strength” as used herein refers to the maximum stress that a material can withstand under tension before it begins to permanently change shape, as measured according to ASTM D638 at 23°C and a strain rate of 0.85 mm / s.

[0047] The term “yield tensile elongation” as used herein refers to the ratio between the increase in length at the yield point and the initial length, as measured according to ASTM D638 at 23°C and a strain rate of 0.85 mm / s.

[0048] The term “tensile strength at break” as used herein refers to the maximum stress that a material can withstand under tension before fracture, as measured according to ASTM D638 at 23°C and a strain rate of 0.85 mm / s.

[0049] The term “elongation at break” as used herein refers to the ratio between the increase in length after fracture and the initial length, as measured according to ASTM D638 at 23°C and a strain rate of 0.85 mm / s.

[0050] The term “Shore A hardness” as used in this article refers to the hardness of a material as measured according to ASTM D2240.

[0051] The term “compression set” as used herein refers to the ability of a material, measured at a specified temperature according to ASTM D395, to return to its original thickness after prolonged compressive stress.

[0052] The term "polyolefin" as used herein refers to polymers that have crystalline and amorphous phases prepared from olefin monomers.

[0053] The term “polyolefin elastomer (POE)” as used herein refers to a low-crystallinity (i.e., less than or equal to 25% crystallinity) polymer prepared from olefin monomers.

[0054] The term "silane-grafted" as used herein refers to a thermoplastic elastomer having silane side chains connected to the polymer backbone.

[0055] The term "copolymer" as used herein refers to a polymer formed when two or more different monomers are polymerized to form a chain.

[0056] The term "block" as used herein refers to a portion of a polymer that comprises a number of structural units and has at least one feature that is not present in adjacent portions.

[0057] As mentioned above, crosslinked thermoplastic articles can possess desired properties, including chemical resistance and heat resistance. However, conventional manufacturing methods may require additional steps, time, and materials to achieve the crosslinking density and heat resistance required for certain applications, including, for example, healthcare, automotive, and electronics applications. Furthermore, conventional methods for curing conjugated diene rubber with peroxides are limited to batch processes because conjugated dienes are highly reactive with peroxides, and it is difficult to control the crosslinking reaction in the extruder. Such reactions can also cause the extruder to "stick" or introduce other complications in the process.

[0058] This invention relates to peroxide-curable compositions comprising thermoplastic elastomers, nitrile rubber, and vulcanizing packages containing repeating units derived from conjugated diene monomers. The thermoplastic elastomer is at least partially derived from the conjugated diene monomer. For the purposes of this specification, a thermoplastic elastomer comprising repeating units derived from conjugated diene monomers may be simply referred to as a "thermoplastic elastomer." The vulcanizing package comprises a silane crosslinking agent and an organic peroxide. The peroxide-curable compositions can be extruded or injection molded and optionally further moisture-cured to form crosslinked polymer articles without the use of a catalyst.

[0059] This article discloses peroxide-curable compositions that exhibit advantageous crosslinking density (e.g., reduced elongation at break) and heat resistance (e.g., reduced compression set) compared to non-crosslinked thermoplastic elastomers based on conjugated dienes (i.e., without silane and peroxide vulcanizing packages). The vulcanizing package containing organic peroxides and silanes enables carbon-carbon crosslinking of the thermoplastic elastomer and nitrile rubber during blending without the need for additional steps or materials, such as moisture-curing catalysts.

[0060] Conventional methods for forming crosslinked polymer articles include a silane grafting step, in which a thermoplastic polymer is crosslinked via reactive extrusion using a silane crosslinking agent, followed by a conversion step, in which the crosslinked polymer is formed into an article by extrusion or injection molding. The silane grafting step increases costs in several ways: specialized equipment and operation for reactive extrusion, different reactive extrusion apparatuses required for thermoplastic polymers with different properties, and packaging and storage of the crosslinked thermoplastic polymer, which has a shelf life until it becomes unsuitable for further extrusion or injection molding. The peroxide-curable compositions disclosed in this invention address these problems in conventional methods by eliminating the need for a separate silane grafting step. The thermoplastic elastomers and nitrile rubbers disclosed in this invention can be directly blended with the silane crosslinking compositions in a conventional conversion process, thus eliminating the initial silane grafting step. Crosslinking of the thermoplastic elastomers and nitrile rubbers is carried out in a one-step process, in which the crosslinked polymer article is formed by extrusion or injection molding. Therefore, the costs and process considerations associated with the silane grafting step can be eliminated. Furthermore, different types of rubbers and polymers can be flexibly included in the peroxide vulcanizable composition without being limited by reactive extrusion processes. Therefore, the peroxide vulcanizable compositions disclosed in this invention significantly reduce manufacturing costs and improve the formulation flexibility of crosslinked thermoplastic polymers.

[0061] polymer composition

[0062] The peroxide-curable compositions disclosed herein can generally be described as thermoplastic elastomers, nitrile rubbers, and vulcanizing packages comprising organic peroxides and silanes. In each aspect, the polymer composition comprises a thermoplastic elastomer and a conjugated diene rubber.

[0063] thermoplastic elastomers

[0064] Thermoplastic elastomers are elastomers comprising repeating units derived from conjugated diene monomers. In any exemplary aspect, the thermoplastic elastomer of the peroxide-curable composition may comprise vinyl aromatic monomer units and conjugated diene monomer units. The conjugated diene monomer units may be selected from 1,3-butadiene monomer units, 2,3-dimethyl-1,3-butadiene, pentadiene monomer units, isoprene monomer units, and combinations thereof. The vinyl aromatic monomer units may be selected from styrene monomer units, α-methylstyrene monomer units, p-methylstyrene monomer units, o-methylstyrene monomer units, p-butylstyrene monomer units, p-tert-butylstyrene monomer units, and combinations thereof.

[0065] In any exemplary aspect, the thermoplastic elastomer may be selected from styrene-butadiene rubber, styrene-butadiene block copolymer, styrene-isoprene block copolymer, styrene-butadiene-isoprene block copolymer, non-hydrogenated styrene-butadiene rubber, non-hydrogenated styrene-butadiene block copolymer, non-hydrogenated styrene-isoprene block copolymer, non-hydrogenated styrene-butadiene-isoprene rubber, non-hydrogenated styrene-butadiene / isoprene block copolymer, non-hydrogenated styrene-butadiene-isoprene block copolymer, and combinations thereof.

[0066] According to any exemplary aspect, the thermoplastic elastomer may be a block copolymer comprising blocks defined by formula (I):

[0067]

[0068] The w, x, y, and z units are randomly distributed in the block, each R1 is independently a hydrogen atom or a methyl group, and each R2 is independently a hydrogen atom or a methyl group, provided that at least one R2 of each unit is a hydrogen atom.

[0069] In the thermoplastic elastomer defined by formula (I), the molar percentage of the sum of y and z units in the sum of w, x, y, and z units in the block can be from about 30% to about 90%. The molar percentage of the sum of y and z units in the sum of w, x, y, and z units in the block can be from about 50% to about 70%. The molar percentage of the sum of y and z units in the sum of w, x, y, and z units in the block can be greater than or equal to about 30%, greater than or equal to about 35%, greater than or equal to about 40%, greater than or equal to about 45%, or even greater than or equal to about 50%. The molar percentage of the sum of y and z units in the sum of w, x, y, and z units in the block can be less than or equal to about 90%, less than or equal to about 85%, less than or equal to about 80%, less than or equal to about 75%, or even less than or equal to about 70%. The molar percentage of the sum of y and z units in the sum of w, x, y and z units in a block can be about 30% to about 90%, about 30% to about 85%, about 30% to about 80%, about 30% to about 75%, about 30% to about 70%, about 35% to about 90%, about 35% to about 85%, about 35% to about 80%, about 35% to about 75%, about 35% to about 70%, about 40% to about 90%, about 40% to about 85%, about 40% to about 80%, about 40% to about 75%, about 40% to about 70%, about 45% to about 90%, about 45% to about 80%, about 45% to about 75%, about 45% to about 70%, about 50% to about 90%, about 50% to about 85%, about 50% to about 80%, about 50% to about 75%, or about 50% to about 70%, or any and all endpoints or sub-ranges therein.

[0070] In the thermoplastic elastomer defined by equation (I), the ratio of y-units to w-units can be greater than the ratio of x-units to z-units. The ratio of y-units to w-units can also be less than the ratio of x-units to z-units.

[0071] In any or all of the respects described herein, the thermoplastic elastomer may be a block copolymer comprising blocks as defined by formula (II):

[0072] (II)

[0073] Units a, b, c, and d are randomly distributed within the block.

[0074] In the thermoplastic elastomer defined by formula (II), the molar percentage of the sum of units c and d in the sum of units a, b, c, and d in the block can be from about 30% to about 90%. The molar percentage of the sum of units c and d in the sum of units a, b, c, and d in the block can be from about 50% to about 70%. The molar percentage of the sum of units c and d in the sum of units a, b, c, and d in the block can be greater than or equal to about 30%, greater than or equal to about 35%, greater than or equal to about 40%, greater than or equal to about 45%, or even greater than or equal to about 50%. The molar percentage of the sum of units c and d in the sum of units a, b, c, and d in the block can be less than or equal to about 90%, less than or equal to about 85%, less than or equal to about 80%, less than or equal to about 75%, or even less than or equal to about 70%. The molar percentage of the sum of units c and d in the sum of units a, b, c and d in the block can be about 30% to about 90%, about 30% to about 85%, about 30% to about 80%, about 30% to about 75%, about 30% to about 70%, about 35% to about 90%, about 35% to about 85%, about 35% to about 80%, about 35% to about 75%, about 35% to about 70%, about 40% to about 90%, about 40% to about 85%, about 40% to about 80%, about 40% to about 75%, about 40% to about 70%, about 45% to about 90%, about 45% to about 80%, about 45% to about 75%, about 45% to about 70%, about 50% to about 90%, about 50% to about 85%, about 50% to about 80%, about 50% to about 75%, or about 50% to about 70%, or any and all endpoints and sub-ranges therein.

[0075] In the thermoplastic elastomer defined by equation (II), the ratio of c-unit to a-unit can be greater than the ratio of d-unit to b-unit. The ratio of c-unit to a-unit can also be less than the ratio of d-unit to b-unit.

[0076] Depending on the specifics, the thermoplastic elastomer can be a triblock copolymer comprising two polystyrene end blocks. The styrene content of the two polystyrene end blocks in the thermoplastic elastomer can be from about 10% by weight to about 50% by weight. The styrene content of the two polystyrene end blocks in the thermoplastic elastomer can be greater than or equal to about 10% by weight, greater than or equal to about 15% by weight, greater than or equal to about 20% by weight, greater than or equal to about 25% by weight, or even greater than or equal to about 27% by weight. The styrene content of the two polystyrene end blocks in the thermoplastic elastomer can be less than or equal to about 50% by weight, less than or equal to about 45% by weight, less than or equal to about 40% by weight, less than or equal to about 35% by weight, or even less than or equal to about 33% by weight. The styrene content of the two polystyrene end blocks in the thermoplastic elastomer may be from about 10% to about 50% by weight, from about 10% to about 45% by weight, from about 10% to about 40% by weight, from about 10% to about 35% by weight, from about 10% to about 33% by weight, from about 15% to about 50% by weight, from about 15% to about 45% by weight, from about 15% to about 40% by weight, from about 15% to about 35% by weight, and from about 15% to about 33% by weight. About 20% by weight to about 50% by weight, about 20% by weight to about 45% by weight, about 20% by weight to about 40% by weight, about 20% by weight to about 35% by weight, about 20% by weight to about 33% by weight, about 25% by weight to about 50% by weight, about 25% by weight to about 45% by weight, about 25% by weight to about 40% by weight, about 25% by weight to about 35% by weight, about 25% by weight to about 33% by weight, about 27% by weight to about 50% by weight, about 27% by weight to about 45% by weight, about 27% by weight to about 40% by weight, about 27% by weight to about 35% by weight, or about 27% by weight to about 33% by weight, or any and all endpoints and sub-ranges thereof.

[0077] In any or all of the aspects described herein, the number-average molecular weight of the thermoplastic elastomer can be from about 30,000 g / mol to about 400,000 g / mol. For example, the number-average molecular weight of the thermoplastic elastomer can be greater than or equal to 30,000 g / mol, greater than or equal to about 50,000 g / mol, greater than or equal to about 100,000 g / mol, or even greater than or equal to about 150,000 g / mol. The number-average molecular weight of the thermoplastic elastomer can also or alternatively be less than or equal to about 400,000 g / mol, less than or equal to about 350,000 g / mol, less than or equal to about 300,000 g / mol, or even less than or equal to about 250,000 g / mol. According to one or more aspects described herein, the number-average molecular weight of the thermoplastic elastomer can be from about 30,000 g / mol to about 400,000 g / mol, from about 30,000 g / mol to about 350,000 g / mol, from about 30,000 g / mol to about 300,000 g / mol, from about 30,000 g / mol to about 250,000 g / mol, from about 50,000 g / mol to about 400,000 g / mol, from about 50,000 g / mol to about 350,000 g / mol, from about 50,000 g / mol to about 300,000 g / mol, or from about 50,000 g / mol to about 250,000 g / mol. l, about 100,000 g / mol to about 400,000 g / mol, about 100,000 g / mol to about 350,000 g / mol, about 100,000 g / mol to about 300,000 g / mol, about 100,000 g / mol to about 250,000 g / mol, about 150,000 g / mol to about 400,000 g / mol, about 150,000 g / mol to about 350,000 g / mol, about 150,000 g / mol to about 300,000 g / mol, or even about 150,000 g / mol to about 250,000 g / mol, or any and all endpoints and subranges thereof.

[0078] According to the present invention, when the thermoplastic elastomer has carbon-carbon double bond sites, the carbon-carbon double bonds are non-hydrogenated or partially hydrogenated. Without being bound by theory, it is believed that crosslinking of the thermoplastic elastomer occurs at least partially at non-hydrogenated sites (i.e., carbon-carbon double bonds). The amount of crosslinking can also be controlled by controlling the level of hydrogenation. It is also believed that the lack of hydrogenation in the thermoplastic elastomer can improve the crosslinking density and heat resistance of the resulting crosslinked polymer system. Therefore, in any aspect disclosed herein, the degree of hydrogenation of the thermoplastic elastomer can be less than 1%, and preferably 0%, based on the unsaturated groups of the conjugated diene monomer unit in the thermoplastic elastomer.

[0079] Depending on various factors, thermoplastic elastomers can be block copolymers with hard and soft phases, generally with the following configuration:

[0080] AB,

[0081] ABA, or

[0082] AB-A',

[0083] Prior to hydrogenation, each A and A' block is a hard phase composed of vinyl aromatic monomer units, and each B block is a soft phase composed of conjugated diene monomer units. The "hard phase" refers to a portion of the block copolymer with a glass transition temperature between 90°C and 165°C. The "soft phase" refers to a portion of the block copolymer with a glass transition temperature less than -20°C.

[0084] In all aspects, the peroxide-curable composition includes a thermoplastic polymer in an amount of about 25% to about 95% by weight, based on the total weight of the peroxide-curable composition. For example, based on the total weight of the peroxide-curable composition, the peroxide-curable composition may include a thermoplastic polymer in an amount of about 25% to about 95% by weight, about 30% to about 85% by weight, or about 35% to about 75% by weight, including any and all endpoints and subranges therein.

[0085] Nitrile rubber

[0086] In all aspects described herein, the peroxide-curable composition further comprises nitrile rubber. Based on the total weight of the peroxide-curable composition, the peroxide-curable composition may comprise nitrile rubber in an amount of about 15% to about 50% by weight. For example, the peroxide-curable composition may comprise nitrile rubber in an amount of about 15% to about 50% by weight, about 18% to about 45% by weight, or about 20% to about 40% by weight, including any and all endpoints and subranges therein.

[0087] vulcanized bags

[0088] The vulcanizing package of the peroxide-curable composition comprises a silane crosslinking agent and an organic peroxide. As described herein, the vulcanizing package promotes peroxide vulcanization, resulting in carbon-carbon crosslinking of the thermoplastic elastomer and nitrile rubber during blending, without the need for additional steps or materials. During the blending of the peroxide-curable composition to form a crosslinked polymer system, the thermoplastic elastomer and nitrile rubber can be grafted with the silane portion. The blend can be aged so that the crosslinked polymer system forms silane crosslinks from the silane grafting.

[0089] The silane crosslinking agent for the vulcanizing package can include a variety of silanes. Examples of suitable silanes include those represented by the following formula:

[0090] SiR x H 4-x

[0091] Where x is 1-4, and each R is a monovalent hydrocarbon group or a monovalent alkoxy group individually and independently.

[0092] In all aspects, the monovalent hydrocarbon group can be a straight-chain, cyclic, or branched group. The monovalent hydrocarbon group can have 1-12 carbon atoms, 2-10 carbon atoms, or 3-8 carbon atoms. The monovalent hydrocarbon group may include one or more carbon-carbon double bonds. The monovalent hydrocarbon group may include one or more aromatic groups.

[0093] According to the present invention, a monovalent alkoxy group can be a monovalent hydrocarbon group attached to an oxygen atom. The monovalent hydrocarbon group of the monovalent alkoxy group can be a straight-chain, cyclic, or branched group. The monovalent hydrocarbon group of the monovalent alkoxy group can have 1-12 carbon atoms, 2-10 carbon atoms, or 3-8 carbon atoms. The monovalent hydrocarbon group of the monovalent alkoxy group can include one or more carbon-carbon double bonds. The monovalent hydrocarbon group of the monovalent alkoxy group can include one or more aromatic groups.

[0094] In any exemplary aspect, the silane crosslinker may include vinyltrialkoxysilane. For example, the silane crosslinker may comprise vinyltrimethoxysilane, vinyltriethoxysilane, or a combination thereof.

[0095] The specific gravity of the silane crosslinking agent can be greater than or equal to about 0.90 or greater than or equal to about 0.95. The specific gravity of the silane can be less than or equal to about 1.05 or less than or equal to about 1. The specific gravity of the silane can be about 0.90 to about 1.05, about 0.90 to about 1.00, about 0.95 to about 1.05, or about 0.95 to about 1.00, including any and all endpoints and subranges therein.

[0096] In any aspect disclosed herein, the boiling point of the silane crosslinking agent may be greater than or equal to about 75°C or greater than or equal to about 100°C. The boiling point of the silane crosslinking agent may be less than or equal to about 150°C or less than or equal to about 125°C. For example, the boiling point of the silane crosslinking agent may be about 75°C to about 150°C, about 75°C to about 125°C, about 100°C to about 150°C, or about 100°C to about 125°C, including any and all endpoints and subranges therein.

[0097] In any aspect disclosed herein, the number-average molecular weight of the silane crosslinking agent may be greater than or equal to about 50 g / mol, greater than or equal to about 100 g / mol, greater than or equal to 150 g / mol, or greater than or equal to about 200 g / mol. The number-average molecular weight of the silane crosslinking agent may be less than or equal to about 500 g / mol, less than or equal to about 400 g / mol, or less than or equal to about 300 g / mol. The number average molecular weight of the silane crosslinking agent can be from about 50 g / mol to about 500 g / mol, from about 50 g / mol to about 400 g / mol, from about 50 g / mol to about 300 g / mol, from about 100 g / mol to about 500 g / mol, from about 100 g / mol to about 400 g / mol, from about 100 g / mol to about 300 g / mol, from about 150 g / mol to about 500 g / mol, from about 150 g / mol to about 400 g / mol, from about 150 g / mol to about 300 g / mol, from about 200 g / mol to about 500 g / mol, from about 200 g / mol to about 400 g / mol, or from about 200 g / mol to about 300 g / mol, including any and all endpoints and subranges therein.

[0098] Examples of commercially available suitable silane crosslinking agents include SILQUEST from Momentive. TM A-171 grade vinyltrimethoxysilane.

[0099] As described above, the vulcanizing package further includes an organic peroxide. The organic peroxide in the vulcanizing package can include a variety of peroxides, and there are no particular limitations. Examples of suitable peroxides include peroxides represented by the following formula:

[0100] ROOR

[0101] Each R is a single, independent monovalent hydrocarbon group. According to the present invention, the monovalent hydrocarbon group of the organic peroxide can be a straight-chain, cyclic, or branched group. The monovalent hydrocarbon group of the organic peroxide can have 1-16 carbon atoms, 3-12 carbon atoms, or 5-10 carbon atoms. The monovalent hydrocarbon group of the organic peroxide can include one or more carbon-carbon double bonds. The monovalent hydrocarbon group of the organic peroxide can include one or more aromatic groups. According to the present invention, the organic peroxide can include peroxyketal peroxide, ditert-alkyl peroxide, or combinations thereof. For example, the organic peroxide can include dicumyl peroxide (a ditert-alkyl peroxide).

[0102] According to the disclosure of this invention, the density of organic peroxides can be greater than or equal to about 1.00 g / cm³. 3 , or greater than or equal to approximately 1.05 g / cm³ 3The density of organic peroxides can be less than or equal to about 1.20 g / cm³. 3 or less than or equal to approximately 1.15 g / cm³ 3 The density of organic peroxides can be approximately 1.00 g / cm³. 3 Approximately 1.20 g / cm³ 3 Approximately 1.00 g / cm³ 3 Approximately 1.15 g / cm³ 3 Approximately 1.05 g / cm³ 3 Approximately 1.20 g / cm³ 3 or approximately 1.05 g / cm³ 3 Approximately 1.15 g / cm³ 3 This includes any and all endpoints and subranges within it.

[0103] Examples of commercially available suitable organic peroxides include BC-FF grade dicumyl peroxide from AkzoNobel, branded PERKADOX®.

[0104] According to the disclosure of this invention, the dry weight ratio of the silane crosslinking agent and the organic peroxide in the vulcanizing package can be 3:1 or greater, 4:1 or greater, or 5:1 or greater. The dry weight ratio of the silane crosslinking agent and the organic peroxide in the vulcanizing package can be 20:1 or less, 15:1 or less, or 10:1 or less. The dry weight ratio of the silane crosslinking agent and the organic peroxide in the vulcanizing package can be 3:1-20:1, 3:1-15:1, 3:1-10:1, 4:1-20:1, 4:1-15:1, 4:1-10:1, 5:1-20:1, 5:1-15:1, 5:1-10:1, including any and all endpoints and sub-ranges therein. The dry weight of the silane crosslinking agent and organic peroxide in the vulcanizing package can be 0.5% to 10% of the mass of the thermoplastic elastomer in the polymer granules, including 1% to 8%, 2% to 7% and 3% to 6%.

[0105] In any aspect disclosed herein, the vulcanizing package may be in the form of a dried silane masterbatch comprising a carrier material loaded with a silane crosslinking agent and an organic peroxide. The carrier material may include porous pellets, filler materials (e.g., silica, talc, calcium carbonate, microspheres, etc.) or combinations thereof. The porous pellets may include high-porosity pellets, such as plastics selected from polypropylene, ethylene vinyl acetate, polyethylene, and mixtures thereof. The carrier material may be loaded by immersing it in a solution containing a silane crosslinking agent, an organic peroxide, and other components (if present) (e.g., additives), and then drying the carrier material to remove the solvent from the solution. Based on the dry weight ratio of silane / peroxide to carrier, the silane / peroxide loading of the carrier material may be 20% or more, 30% or more, or 40% or more. Based on the dry weight ratio of silane / peroxide to carrier, the silane / peroxide loading of the carrier material may be 80% or less, 70% or less, or 60% or less. Based on the dry weight ratio of silane / peroxide to carrier, the silane / peroxide loading of the carrier material can be 20% to 80%, 20% to 70%, 20% to 60%, 30% to 80%, 30% to 70%, 30% to 60%, 40% to 80%, 40% to 70%, 40% to 60%, including any and all endpoints and subranges therein. The dried silane masterbatch can be dry-blended with polymer granules and fed into extrusion or injection molding processes for crosslinking thermoplastic elastomers.

[0106] Vulcanizing packages can exist in the form of solutions, dispersions, or emulsions containing silane crosslinking agents and organic peroxides. When forming dry silanes, vulcanizing packages can be blended with porous granules to form dry silane masterbatches, which can then be fed into extrusion or injection molding processes for crosslinking thermoplastic elastomers and nitrile rubber. Alternatively, or in addition to dry silanes, vulcanizing packages can be directly injected into molten polymer granules during extrusion or injection molding.

[0107] The peroxide-curable composition may contain about 0.5 wt% to about 5 wt% of silane. In any exemplary aspect, the amount of silane in the peroxide-curable composition may be greater than or equal to about 0.5 wt%, including, for example, at least 0.75 wt%, at least 0.9 wt%, at least 1 wt%, at least 1.25 wt%, at least 1.5 wt%, at least 1.75 wt%, or at least 2 wt%, including all endpoints and subranges therebetween. In any exemplary aspect, the amount of silane in the peroxide-curable composition may be less than or equal to about 5 wt%, including, for example, less than or equal to about 4.75 wt%, less than or equal to 4.5 wt%, less than or equal to 4.2 wt%, less than or equal to 4 wt%, less than or equal to 3.7 wt%, less than or equal to 3.5 wt%, less than or equal to 3.2 wt%, or less than or equal to about 3 wt%, including all endpoints and subranges therebetween. The amount of silane in the peroxide-curable composition can be from 0.5% to 5% by weight, including, for example, 0.5% to about 4% by weight, about 0.5% to about 3% by weight, about 1% to about 5% by weight, about 1% to about 4% by weight, or about 1% to about 3% by weight, including any endpoints and subranges therein.

[0108] While not wishing to be bound by theory, it is believed that increasing the amount of organic peroxide in the peroxide-curable composition improves the crosslinking density and heat resistance of the resulting crosslinked thermoplastic elastomer. In any aspect disclosed herein, the peroxide-curable composition may contain about 0.05% by weight to about 1% by weight of organic peroxide. The amount of organic peroxide in the peroxide-curable composition may be greater than or equal to about 0.05% by weight, greater than or equal to about 0.1% by weight, or even greater than or equal to about 0.2% by weight. The amount of organic peroxide in the peroxide-curable composition may be less than or equal to about 1% by weight, less than or equal to about 0.8% by weight, less than or equal to about 0.6% by weight, or even less than or equal to about 0.4% by weight. The amount of organic peroxide in the peroxide-curable composition may be from about 0.05 wt% to about 1 wt%, from about 0.05 wt% to about 0.8 wt%, from about 0.05 wt% to about 0.6 wt%, from about 0.05 wt% to about 0.4 wt%, from about 0.1 wt% to about 1 wt%, from about 0.1 wt% to about 0.8 wt%, from about 0.1 wt% to about 0.6 wt%, from about 0.1 wt% to about 0.4 wt%, from about 0.2 wt% to about 1 wt%, from about 0.2 wt% to about 0.8 wt%, from about 0.2 wt% to about 0.6 wt%, or from about 0.2 wt% to about 0.4 wt%, including all endpoints and sub-ranges therein.

[0109] Olefin polymers

[0110] The peroxide-curable composition may further include an olefin polymer to adjust hardness and mechanical properties and improve flow properties. The olefin polymer may include polyolefins, polyolefin elastomers, or combinations thereof. Suitable examples of polyolefins include polypropylene, polyethylene, or combinations thereof. The polyolefin may be high-density polyethylene (e.g., greater than or equal to 0.940 g / cm³). 3 It is one of the following: ) or crystalline polypropylene with a crystallinity percentage of at least 60%.

[0111] According to the disclosure of this invention, olefin polymers may include polypropylene. Polypropylene may include polypropylene homopolymers (i.e., composed of propylene monomers) or products having more than 50% by weight of propylene monomers and one or more additional comonomers such as C2 and C4-C. 12 α-olefin polypropylene copolymers. Polyethylene may include polyethylene homopolymers (i.e., composed of ethylene monomers) or copolymers having more than 50% by weight of ethylene monomers and additional comonomers such as C3-C. 12 Polyethylene copolymers of α-olefins.

[0112] The melt flow rate of polypropylene (230℃ / 2.16kg) can be greater than or equal to about 0.1 g / 10 min, greater than or equal to about 0.5 g / 10 min, greater than or equal to about 1 g / 10 min, or even greater than or equal to about 3 g / 10 min. The melt flow rate of polypropylene (230℃ / 2.16kg) can be less than or equal to about 10 g / 10 min or even less than or equal to about 5 g / 10 min. The melt flow rate (230°C / 2.16 kg) of polypropylene can be about 0.1 g / 10 min to about 10 g / 10 min, about 0.1 g / 10 min to about 5 g / 10 min, about 0.5 g / 10 min to about 10 g / 10 min, about 0.5 g / 10 min to about 5 g / 10 min, about 1 g / 10 min to about 10 g / 10 min, about 1 g / 10 min to about 5 g / 10 min, about 3 g / 10 min to about 10 g / 10 min, or about 3 g / 10 min to about 5 g / 10 min, or any and all subranges formed by any of these endpoints.

[0113] According to the disclosure of this invention, the density of the polyolefin can be greater than or equal to about 0.80 g / cm³. 3 Or even greater than or equal to approximately 0.85 g / cm³ 3 The density of polyolefins can be less than or equal to about 1.10 g / cm³. 3 Or even less than or equal to about 1.00 g / cm³ 3 Polyolefins may include those with a density of approximately 0.80 g / cm³. 3 Approximately 1.10 g / cm³ 3 Approximately 0.80 g / cm³ 3To approximately 1.00 g / cm³ 3 Approximately 0.85 g / cm³ 3 Approximately 1.10 g / cm³ 3 or approximately 0.85 g / cm³ 3 To approximately 1.00 g / cm³ 3 Or any and all subranges formed by any of these endpoints.

[0114] According to the disclosure of this invention, the melting point of polyolefins can be greater than or equal to about 100°C, greater than or equal to about 110°C, or even greater than or equal to about 120°C.

[0115] According to the disclosure of this invention, the yield tensile strength of the polyolefin can be greater than or equal to about 25 MPa or even greater than or equal to about 30 MPa. The yield tensile strength of the polyolefin can be less than or equal to about 45 MPa or even less than or equal to about 40 MPa. The yield tensile strength of the polyolefin can be about 25 MPa to about 45 MPa, about 25 MPa to about 40 MPa, about 30 MPa to about 45 MPa, or about 30 MPa to about 40 MPa, including any and all endpoints and subranges therein.

[0116] According to the disclosure of this invention, the yield tensile elongation of the polyolefin can be greater than or equal to about 3% or even greater than or equal to about 5%. The yield tensile elongation of the polyolefin can be less than or equal to about 20% or even less than or equal to about 15%. The yield tensile elongation of the polyolefin can be about 3% to about 20%, about 3% to about 15%, about 5% to about 20%, or about 5% to about 15%, including any and all endpoints and subranges therein.

[0117] Examples of commercially available suitable polyolefins include 1102KR grade polypropylene homopolymer from Formosa Plastics, branded FORMOLENE®.

[0118] According to the present invention, polyolefin elastomers may include polypropylene elastomers. Examples of commercially available suitable polyolefin elastomers include VISTAMAXX from Exxon. TM Polypropylene elastomer grades 6201 and 6202.

[0119] According to the disclosure of this invention, polyolefin elastomers may include olefin block copolymers, ethylene α-olefin copolymers, or combinations thereof. The olefin block copolymers may contain ethylene α-olefin repeating units. The ethylene α-olefin repeating units are ethylene and C3-C... 12 The polymerization product of olefins. For example, the repeating unit of ethylene α-olefin may include ethylene-octene copolymers, ethylene-hexene copolymers, ethylene-butene copolymers, or combinations thereof.

[0120] According to the disclosure of this invention, the melt flow rate (190°C / 2.16 kg) of the olefin block copolymer can be greater than or equal to about 1 g / 10 min or even greater than or equal to about 5 g / 10 min. The melt flow rate (190°C / 2.16 kg) of the olefin block copolymer can be less than or equal to about 25 g / 10 min or even less than or equal to about 20 g / 10 min. The melt flow rate (190°C / 2.16 kg) of the olefin block copolymer can be about 1 g / 10 min to about 25 g / 10 min, about 1 g / 10 min to about 20 g / 10 min, about 5 g / 10 min to about 25 g / 10 min, or about 5 g / 10 min to about 20 g / 10 min, or any and all subranges formed by any of these endpoints.

[0121] According to the disclosure of this invention, the density of the olefin block copolymer can be greater than or equal to about 0.80 g / cm³. 3 Or even greater than or equal to approximately 0.85 g / cm³ 3 The density of olefin block copolymers can be less than or equal to about 0.95 g / cm³. 3 Or even less than or equal to approximately 0.90 g / cm³ 3 The density of olefin block copolymers can be approximately 0.80 g / cm³. 3 Approximately 0.95 g / cm³ 3 Approximately 0.80 g / cm³ 3 To approximately 0.90 g / cm 3 Approximately 0.85 g / cm³ 3 Approximately 0.95 g / cm³ 3 or approximately 0.85 g / cm³ 3 To approximately 0.90 g / cm 3 This includes any and all endpoints and subranges within it.

[0122] According to the disclosure of this invention, the Shore A hardness of the olefin block copolymer can be greater than or equal to about 50 or even greater than or equal to about 60. The Shore A hardness of the olefin block copolymer can be less than or equal to about 85, or even less than or equal to about 75. The Shore A hardness of the olefin block copolymer can be about 50 to about 85, about 50 to about 75, about 60 to about 85, or about 60 to about 75, including any and all endpoints and subranges therein.

[0123] Examples of commercially available suitable olefin block copolymers include INFUSE, a trademark of Dow Chemical Company. TM 9500 and 9817.

[0124] Ethylene α-olefin copolymers are ethylene and C3-C 12Polymerization products of olefins. For example, ethylene α-olefin copolymers may include ethylene-octene copolymers, ethylene-hexene copolymers, ethylene-butene copolymers, or combinations thereof.

[0125] According to the disclosure of this invention, the melt flow rate (190°C / 2.16 kg) of the ethylene-α-olefin copolymer can be greater than or equal to 0.1 g / 10 min or even greater than or equal to 0.25 g / 10 min. The melt flow rate (190°C / 2.16 kg) of the ethylene-α-olefin copolymer can be less than or equal to 3 g / 10 min or even less than or equal to 1 g / 10 min. The melt flow rate (190°C / 2.16 kg) of the ethylene-α-olefin copolymer can be from 0.1 g / 10 min to 3 g / 10 min, from 0.1 g / 10 min to 1 g / 10 min, from 0.25 g / 10 min to 3 g / 10 min, or even from 0.25 g / 10 min to 1 g / 10 min, including any and all endpoints and subranges therein.

[0126] According to the disclosure of this invention, the density of the ethylene-α-olefin copolymer can be greater than or equal to 0.80 g / cm³. 3 Or even greater than or equal to 0.85 g / cm³ 3 The density of ethylene-α-olefin copolymers can be less than or equal to 0.95 g / cm³. 3 Or even less than or equal to 0.90 g / cm³ 3 The density of ethylene-α-olefin copolymers can be 0.80 g / cm³. 3 Up to 0.95 g / cm 3 0.80 g / cm 3 Up to 0.90 g / cm 3 0.85g / cm 3 Up to 0.95 g / cm 3 , or even 0.85g / cm 3 Up to 0.90 g / cm 3 This includes any and all endpoints and subranges within it.

[0127] According to the disclosure of this invention, the Mooney viscosity (ML 1+4, 121°C) of the ethylene-α-olefin copolymer can be greater than or equal to 20, greater than or equal to 30, or even greater than or equal to 40. The Mooney viscosity (ML 1+4, 121°C) of the ethylene-α-olefin copolymer can be less than or equal to 70, less than or equal to 60, or even less than or equal to 50. The Mooney viscosity (ML 1+4, 121°C) of the ethylene-α-olefin copolymer can be 20 to 70, 20 to 60, 20 to 50, 30 to 70, 30 to 60, 30 to 50, 40 to 70, 40 to 60, or 40 to 50, or any and all subranges formed by any of these endpoints.

[0128] According to the disclosure of this invention, the Shore A hardness of the ethylene-α-olefin copolymer can be greater than or equal to 40 or even greater than or equal to 45. The Shore A hardness of the ethylene-α-olefin copolymer can be less than or equal to 60 or even less than or equal to 65. The Shore A hardness of the ethylene-α-olefin copolymer can be 40 to 60, 40 to 55, 45 to 60, or 45 to 55, or any and all subranges formed by any of these endpoints.

[0129] Examples of commercially available suitable ethylene-α-olefin copolymers include the trademark ENGAGE from Dow Chemical Company. TM XLT 8677.

[0130] According to the disclosure of this invention, crosslinkable thermoplastic polymer blends may contain about 2% to about 50% olefin polymers, about 4% to about 40% olefin polymers, or about 6% to about 30% olefin polymers. The amount of olefin polymer in the crosslinkable thermoplastic polymer blend may be greater than or equal to about 2% wt%, greater than or equal to about 4% wt%, or even greater than or equal to about 6% wt. The amount of olefin polymer in the crosslinkable thermoplastic polymer blend may be less than or equal to about 50% wt%, less than or equal to about 40% wt%, less than or equal to about 30% wt%, less than or equal to about 20% wt%, less than or equal to about 17% wt%, less than or equal to about 15% wt%, less than or equal to about 13% wt%, or even less than or equal to about 10% wt. The amount of olefin polymer in the crosslinkable thermoplastic polymer blend can be from about 2 wt% to about 50 wt%, from about 2 wt% to about 40 wt%, from about 2 wt% to about 30 wt%, from about 2 wt% to about 20 wt%, from about 2 wt% to about 17 wt%, from about 2 wt% to about 15 wt%, from about 2 wt% to about 13 wt%, from about 2 wt% to about 10 wt%, from about 4 wt% to about 50 wt%, and from about 4 wt% to about 40 wt%. About 4% by weight to about 30% by weight, about 4% by weight to about 20% by weight, about 4% by weight to about 17% by weight, about 4% by weight to about 15% by weight, about 4% by weight to about 13% by weight, about 4% by weight to about 10% by weight, about 6% by weight to about 50% by weight, about 6% by weight to about 40% by weight, about 6% by weight to about 30% by weight, about 6% by weight to about 20% by weight, about 6% by weight to about 17% by weight, about 6% by weight to about 15% by weight, about 6% by weight to about 13% by weight, or about 6% by weight to about 10% by weight, or any and all subranges formed by any of these endpoints.

[0131] plasticizer

[0132] According to the disclosure of this invention, the peroxide-curable composition may further comprise a plasticizer. The plasticizer can help improve flowability in the peroxide-curable composition. According to the disclosure of this invention, the plasticizer may comprise a non-polar plasticizer (e.g., mineral oil).

[0133] According to the disclosure of this invention, the amount of plasticizer in the peroxide vulcanizable composition can be greater than or equal to about 0% by weight, greater than or equal to about 10% by weight, greater than or equal to about 20% by weight, greater than or equal to about 25% by weight, greater than or equal to about 30% by weight, or greater than or equal to about 35% by weight. The amount of plasticizer in the peroxide vulcanizable composition can be less than or equal to about 60% by weight, less than or equal to about 55% by weight, less than or equal to about 50% by weight, less than or equal to about 45% by weight, less than or equal to about 40% by weight, or less than or equal to about 35% by weight. The amount of plasticizer in the peroxide vulcanizable composition can be from about 0% by weight to about 60% by weight, including about 10% by weight to 55% by weight, about 20% by weight to 50% by weight, about 25% by weight to 45% by weight, about 30% by weight to 40% by weight, and any and all subranges formed by any of these endpoints.

[0134] Examples of commercially available suitable plasticizers include PURETOL from Petro-Canada. TM The PSO 380 level.

[0135] Tackifier

[0136] According to the disclosure of the present invention, the peroxide vulcanizable composition may further include a tackifier for adhesive applications (e.g., hot melt adhesives).

[0137] According to the disclosure of this invention, the tackifier may include a hydrocarbon resin. Exemplary hydrocarbon resins may include aliphatic resins (e.g., C5 resins), aromatic resins (e.g., C9 resins), dicyclopentadiene resins, and resins comprising two or more of aliphatic monomers, aromatic monomers, and dicyclopentadiene. The hydrocarbon resin may be hydrogenated. According to the disclosure of this invention, the number average molecular weight of the hydrocarbon resin may be less than or equal to about 2,000 g / mol, less than or equal to about 1,500 g / mol, less than or equal to about 1,200 g / mol, less than or equal to about 1,100 g / mol, less than or equal to about 1,000 g / mol, or less than or equal to about 900 g / mol.

[0138] According to the disclosure of this invention, the peroxide vulcanizable composition may contain about 15% to about 50% by weight of a tackifier, or about 17% to about 40% by weight of a tackifier, or about 20% to about 30% by weight of a tackifier. The amount of tackifier in the peroxide vulcanizable composition may be greater than or equal to about 15% by weight, greater than or equal to about 17% by weight, or even greater than or equal to about 20% by weight. The amount of tackifier in the peroxide vulcanizable composition may be less than or equal to about 50% by weight, less than or equal to about 40% by weight, less than or equal to about 30% by weight, less than or equal to about 27% by weight, or even less than or equal to about 25% by weight. The amount of tackifier in the peroxide vulcanizable composition may be from about 15% to about 50% by weight, from about 15% to about 40% by weight, from about 15% to about 30% by weight, from about 15% to about 27% by weight, from about 15% to about 25% by weight, from about 17% to about 50% by weight, from about 17% to about 40% by weight, from about 17% to about 30% by weight, from about 17% to about 27% by weight, from about 17% to about 25% by weight, from about 20% to about 50% by weight, from about 20% to about 40% by weight, from about 20% to about 30% by weight, from about 20% to about 27% by weight, or even from about 20% to about 25% by weight, or any and all endpoints and subranges therebetween.

[0139] Examples of commercially available suitable tackifiers include PLASTOLYN from Eastman Chemicals. TM R1140 level.

[0140] Cocrosslinkable polymers

[0141] According to the disclosure of the present invention, the peroxide vulcanizable composition may further comprise a co-crosslinkable polymer that can be crosslinked with thermoplastic elastomers and nitrile rubber via a vulcanizing package.

[0142] According to the disclosure of this invention, the co-crosslinkable polymer may include ethylene-vinyl acetate. Based on the total weight of the ethylene-vinyl acetate, the vinyl acetate content of the ethylene-vinyl acetate may be greater than or equal to about 10% by weight, greater than or equal to about 25% by weight, greater than or equal to about 40% by weight, or even greater than or equal to 55% by weight. The vinyl acetate content of the ethylene-vinyl acetate may be less than or equal to about 80% by weight, less than or equal to about 70% by weight, or even less than or equal to about 60% by weight. The vinyl acetate content of ethylene-vinyl acetate can be from about 10% by weight to about 80% by weight, from about 10% by weight to about 70% by weight, from about 10% by weight to about 60% by weight, from about 25% by weight to about 80% by weight, from about 25% by weight to about 70% by weight, from about 25% by weight to about 60% by weight, from about 40% by weight to about 80% by weight, from about 40% by weight to about 70% by weight, from about 40% by weight to about 60% by weight, from about 55% by weight to about 80% by weight, from about 55% by weight to about 70% by weight, or from about 55% by weight to about 60% by weight, or any and all endpoints and subranges therebetween.

[0143] According to the disclosure of this invention, the peroxide vulcanizable composition may contain about 25% to about 45% by weight of a cocrosslinkable polymer, or about 27% to about 43% by weight of a cocrosslinkable polymer, or about 30% to about 40% by weight of a cocrosslinkable polymer. The amount of cocrosslinkable polymer in the crosslinkable thermoplastic polymer blend may be greater than or equal to about 25% by weight, greater than or equal to about 27% by weight, or even greater than or equal to about 30% by weight. The amount of cocrosslinkable polymer in the peroxide vulcanizable composition may be less than or equal to about 45% by weight, less than or equal to about 43% by weight, or even less than or equal to about 40% by weight. The amount of co-crosslinkable polymer in the peroxide vulcanizable composition may be from about 25% to about 45% by weight, from about 25% to about 43% by weight, from about 25% to about 40% by weight, from about 27% to about 45% by weight, from about 27% to about 43% by weight, from about 27% to about 40% by weight, from about 30% to about 45% by weight, from about 30% to about 43% by weight, or from about 30% to about 40% by weight, or any and all endpoints and subranges thereof.

[0144] Examples of commercially available suitable co-vulcanizable polymers include ELVAX from Dow Chemical Company. TM Level 265.

[0145] additive

[0146] According to the disclosure of this invention, the peroxide vulcanizable composition may further comprise one or more additives. The additives may include adhesion promoters; biocides; antifogging agents; antistatic agents; foaming agents; adhesives and bonding polymers; dispersants; flame retardants and smoke suppressants; mineral fillers; initiators; lubricants; mica; pigments, colorants and dyes; processing aids; release agents; silanes, titanates and zirconates; slip agents and anti-blocking agents; stearates; ultraviolet absorbers; viscosity modifiers; waxes; or combinations thereof.

[0147] Crosslinking of thermoplastic elastomers and nitrile rubber

[0148] According to the disclosure of this invention, a peroxide-curable composition comprising polymer pellets, a vulcanizing bag, and optional components such as an olefin polymer, a plasticizer, or a tackifier can be blended to form a crosslinked polymer article having advantageous crosslinking density and heat resistance. In some aspects, the crosslinked polymer article may be a thermoplastic vulcanizate rubber.

[0149] In any exemplary aspect, the peroxide-curable composition may comprise 90 to 99.9 parts of polymer pellets and 0.1 to 10 parts of vulcanizing packets, including, for example, 94 to 99.5 parts of polymer pellets and 0.5 to 5 parts of vulcanizing packets. In any exemplary aspect, based on the dry weight of the vulcanizing packets, the peroxide-curable composition may comprise, in amounts from 0.1% to 10%, including, for example, 0.2% to 6%, 0.3% to 4%, 0.5% to 3%, and 1.0% to 2% of vulcanizing packets, including all endpoints and subranges therein, relative to the weight of the thermoplastic elastomer and nitrile rubber in the polymer pellets.

[0150] Crosslinked polymer articles can be prepared by batch or continuous methods. Blending (also known as compounding) apparatus is well known to those skilled in the art and typically includes a feeding device, particularly at least one hopper for powdered materials and / or at least one injection pump for liquid materials; a high-shear blending device, such as a co-rotating or counter-rotating twin-screw extruder, which typically includes a feed screw housed in a heated cylinder (or tube); an output head that shapes the extrudate; and means for cooling the extrudate by air cooling or by water circulation. The extrudate typically exits the apparatus continuously in the form of rods that can be cut or formed into granules. However, other forms can be obtained by assembling a die of the desired shape onto the output die.

[0151] For example, a peroxide-curable composition (i.e., polymer granules, vulcanizing bags, and any additives) can be fed into an extruder (e.g., a 27 mm Leistriz twin extruder (L / D 52)) and blended. Blending (e.g., in the barrel of the extruder) can be carried out at temperatures from 240°F to 500°F (about 115°C to about 260°C). According to the disclosure of the invention, blending results in carbon-carbon crosslinking and grafting of silane moieties onto the thermoplastic elastomer and nitrile rubber.

[0152] As described herein, the vulcanization package comprising both organic peroxides and silanes enables carbon-carbon crosslinking of thermoplastic elastomers and nitrile rubber without the need for additional steps or materials (e.g., moisture-curing catalysts). Therefore, in some aspects, the blending of thermoplastic elastomers and nitrile rubber, organic peroxides, and silanes is carried out in the absence of a catalyst. Furthermore, the blending of thermoplastic elastomers and nitrile rubber, organic peroxides, and silanes can be carried out in the absence of moisture (e.g., water). Thus, silanes can also be grafted onto thermoplastic elastomers and nitrile rubber in an extruder. However, due to the absence of moisture, silane crosslinking does not occur in the extruder or occurs only to a very small extent (to the extent that any crosslinking occurs completely). However, upon exiting the extruder, the thermoplastic elastomers and nitrile rubber contain little or no silane-silane crosslinking. The extrudate can be shaped to form a shaped carbon-carbon crosslinked silane-grafted blend. In some aspects, the formed carbon-carbon crosslinked silane grafted blends are aged (e.g., heat-treated or cured) so that the crosslinked polymer system includes silane-silane crosslinks.

[0153] In the aspects described herein, during extrusion, the elongation at break of the crosslinked polymer system is greater than or equal to about 30%, and the elongation at break of the crosslinked polymer system remains within 5% of the elongation at break of the crosslinked polymer system over 24 hours at room temperature. In any or all of the aspects described herein, during extrusion, the compression set of the crosslinked polymer system is greater than or equal to about 20%, and the compression set of the crosslinked polymer system remains within 5% of the compression set at break of the crosslinked polymer system over 24 hours at room temperature.

[0154] performance

[0155] According to the present invention, the elongation at break of the crosslinked thermoplastic elastomer, measured under ASTM D412, can be from about 30% to about 500%. The elongation at break of the crosslinked thermoplastic elastomer can be greater than or equal to about 30%, greater than or equal to about 50%, or even greater than or equal to about 100%. The elongation at break of the crosslinked thermoplastic elastomer can be less than or equal to about 500%, less than or equal to about 450%, less than or equal to about 400%, less than or equal to about 350%, less than or equal to about 300%, less than or equal to about 250%, or even less than or equal to about 200%. The elongation at break of the crosslinked thermoplastic elastomer can be from about 30% to about 500%, from about 30% to about 450%, from about 30% to about 400%, from about 30% to about 350%, from about 30% to about 300%, from about 30% to about 250%, from about 30% to about 200%, from about 50% to about 500%, from about 50% to about 450%, from about 50% to about 400%, from about 50% to about 350%, from about 50% to about 300%, from about 50% to about 250%, from about 50% to about 200%, from about 100% to about 500%, from about 100% to about 450%, from about 100% to about 400%, from about 100% to about 350%, from about 100% to about 300%, from about 100% to about 250%, or from about 100% to about 200%, or any and all endpoints and sub-ranges thereof.

[0156] According to the disclosure of this invention, the compression set of a crosslinked thermoplastic elastomer, measured at 100°C, can be from about 20% to about 90%. The compression set is measured according to ASTM D395B. The compression set of the crosslinked thermoplastic elastomer can be less than or equal to about 90%, including, for example, compression sets measured at 100°C less than or equal to about 80%, less than or equal to about 70%, less than or equal to about 60%, less than or equal to about 55%, or less than or equal to about 50%. The compression set of the crosslinked thermoplastic elastomer can be from 0% to about 90%, including, for example, about 10% to about 80%, about 15% to about 70%, about 20% to about 65%, about 25% to about 60%, about 27% to about 55%, about 30% to about 50%, about 35% to about 65%, or about 40% to about 60%, or any and all endpoints and subranges therebetween. Low compression set indicates high crosslinking density, where 100% compression set indicates no crosslinking, and 0% compression set indicates a fully crosslinked thermoplastic elastomer.

[0157] According to the disclosure of this invention, the Shore A hardness of the crosslinked thermoplastic elastomer, measured according to ASTM D2240, can be greater than or equal to about 25, including, for example, greater than or equal to about 30, greater than or equal to about 35, greater than or equal to about 40, greater than or equal to about 45, greater than or equal to about 47, greater than or equal to about 50, greater than or equal to about 55, greater than or equal to about 57, or greater than or equal to about 60. The Shore A hardness of the crosslinked thermoplastic elastomer can be less than about 95, including, for example, less than or equal to about 90, less than or equal to about 85, less than or equal to about 80, less than or equal to about 75, or even less than or equal to about 70. The Shore A hardness of the crosslinked thermoplastic elastomer can be about 25 to about 95, about 27 to about 90, about 30 to about 85, about 33 to about 80, about 35 to about 75, about 30 to about 90, about 30 to about 85, about 30 to about 80, about 30 to about 75, about 30 to about 70, about 35 to about 90, about 35 to about 80, about 35 to about 75, about 35 to about 70, about 40 to about 90, about 40 to about 85, about 40 to about 80, about 40 to about 75, about 40 to about 70, about 45 to about 90, about 45 to about 85, about 45 to about 80, about 45 to about 75, or about 45 to about 70, including all endpoints and subranges therein.

[0158] According to the present invention, the crosslinked thermoplastic elastomer has a tensile strength at break measured according to ASTM D412 that is greater than or equal to about 1.5 MPa, greater than or equal to about 2.0 MPa, greater than or equal to about 2.5 MPa, or even greater than or equal to about 3.0 MPa. The crosslinked thermoplastic elastomer may have a tensile strength at break of less than or equal to about 8.0 MPa, including, for example, less than or equal to about 7.5 MPa, less than or equal to about 7.0 MPa, less than or equal to about 6.5 MPa, or even less than or equal to about 6.0 MPa. The tensile strength at break of the crosslinked thermoplastic elastomer can be from about 1.5 MPa to about 8.0 MPa, from about 1.5 MPa to about 7.5 MPa, from about 1.5 MPa to about 7.0 MPa, from about 1.5 MPa to about 6.5 MPa, from about 1.5 MPa to about 6.0 MPa, from about 2.0 MPa to about 8.0 MPa, from about 2.0 MPa to about 7.5 MPa, from about 2.0 MPa to about 7.0 MPa, from about 2.0 MPa to about 6.5 MPa, and from about 2.0 MPa to about 6.0 MPa. Approximately 2.5 MPa to approximately 8.0 MPa, approximately 2.5 MPa to approximately 7.5 MPa, approximately 2.5 MPa to approximately 7.0 MPa, approximately 2.5 MPa to approximately 6.5 MPa, approximately 2.5 MPa to approximately 6.0 MPa, approximately 3.0 MPa to approximately 8.0 MPa, approximately 3.0 MPa to approximately 7.5 MPa, approximately 3.0 MPa to approximately 7.0 MPa, approximately 3.0 MPa to approximately 6.5 MPa, or even approximately 3.0 MPa to approximately 6.0 MPa, including all endpoints and subranges therein.

[0159] According to the disclosure of this invention, the weight gain of a crosslinked thermoplastic elastomer after immersion in 903 oil at 125°C for 3 days can be 170% or less, including 160% or less, 150% or less, 140% or less, 130% or less, and 125% or less. A low weight gain after oil immersion indicates a high crosslinking density, wherein uncrosslinked thermoplastic elastomers will dissolve upon immersion in oil.

[0160] Methods for crosslinking thermoplastic elastomers

[0161] According to the disclosure of this invention, a method for forming a crosslinked thermoplastic elastomer includes blending a thermoplastic elastomer, nitrile rubber, and a vulcanizing package to form a thermoplastic polymer blend. As described above, the vulcanizing package may be a dry silane masterbatch, and the polymer pellets and the dry silane masterbatch are dry-blended. The method further includes melting the thermoplastic polymer blend to form a crosslinkable thermoplastic polymer melt, and extruding or injection molding the crosslinkable thermoplastic polymer melt to form a crosslinked thermoplastic elastomer. The method includes a one-step conversion process in which the thermoplastic elastomer in the polymer pellets is crosslinked, and there is no separate silane grafting process.

[0162] In some aspects of the present invention, carbon-carbon crosslinked thermoplastic elastomers are molded.

[0163] As described above, instead of dry silane masterbatch, the vulcanizing package may include a solution of silane crosslinking agent and organic peroxide. Therefore, instead of dry blending polymer granules and dry silane masterbatch and then melting the resulting thermoplastic polymer blend, the method may include blending one or more polymer granules with a solution: and melting the blend to form a crosslinkable thermoplastic polymer melt, which is then further extruded or injection molded to form a crosslinked thermoplastic elastomer.

[0164] Example

[0165] Table 1 below shows the source of components used to form Comparative Examples C1-C9 and Examples E1-E6.

[0166] Table 1:

[0167]

[0168] Tables 2-4 below show the formulations and certain properties used to form comparative examples C1-C9 and examples E1-E6.

[0169] To prepare the plates for comparative examples C1-C9 and examples E1-E6, the components of the formulations listed in Tables 2-4 were added to a 27 mm Leistriz twin-screw extruder (L / D / 52) and blended at a barrel temperature of 193°C and a rate of 300 rpm. The blended formulations were extruded at a rate of approximately 3.78 g / s to approximately 6.30 g / s. Compression set was measured according to ASTM D395. A 3-day 903 machine oil immersion test was performed on samples in 29 mm disc form with a thickness of 3 mm.

[0170] Table 2

[0171]

[0172] Table 2, continued

[0173]

[0174] Table 3

[0175]

[0176] Table 4

[0177]

[0178] Table 4, continued

[0179]

[0180] As shown in Tables 3-4, compared to peroxide-curable compositions containing thermoplastic elastomers, silanes, and organic peroxides but not nitrile rubber, Examples E1-E6, composed of nitrile rubber (CHEMIGUM® P615D), thermoplastic elastomers (HYBR), and other components, are superior. TM 5217 and / or VECTOR® 2518), silane (SILQUEST) TM The crosslinked polymer system formed by the peroxide vulcanizable composition of A-171 and organic peroxide (PERKADOX® BC-FF) exhibits a significant improvement in oil resistance. Although Table 2 shows that oil resistance is improved upon crosslinking (Comparative Examples C1-C4, compared to Comparative Examples C5-C7), the incorporation of nitrile rubber (Examples E1-E6) results in even greater improvements in oil resistance than crosslinking alone.

[0181] The comparative examples in Table 2 further demonstrate that, when contained in approximately similar weight percentages (Comparative Example C1, compared to Comparative Examples C3-C4), crosslinked SBS exhibits better oil resistance than SIS. However, the addition of nitrile rubber (Examples E1-E6) allows for a reduction in the amount of SBS without sacrificing the improvement in oil resistance.

[0182] As shown in Table 2, compared with comparative examples C5-C7 (non-crosslinked thermoplastic articles formed from compositions containing thermoplastic elastomers but excluding silanes and organic peroxides), those containing thermoplastic elastomers and silanes (SILQUEST) showed a significant improvement. TM The crosslinked polymer systems formed from peroxide-curable compositions of A-171 and an organic peroxide (PERKADOX® BC-FF) (Comparative Examples C1-C4) exhibited reduced elongation at break and reduced compression set. As shown in Tables 3 and 4, the reduction in elongation at break and compression set was maintained upon the addition of nitrile rubber (Examples E1-E6). Therefore, the examples demonstrate that peroxide-curable compositions comprising thermoplastic elastomers, nitrile rubber, silanes, and organic peroxides produce crosslinked polymer systems with improved crosslink density and heat resistance compared to articles not formed using compositions containing silanes and organic peroxides.

[0183] It is obvious that modifications and variations are possible without departing from the scope of the invention disclosure as defined in the appended claims. More specifically, although some aspects of the invention disclosure are identified herein as preferred or particularly advantageous, it is contemplated that the invention disclosure is not necessarily limited to these aspects.

Claims

1. A crosslinked polymer system comprising: Silane-grafted nitrile rubber; and Silane-grafted thermoplastic elastomers comprising repeating units derived from conjugated diene monomers; The silane-grafted nitrile rubber and the silane-grafted thermoplastic elastomer are crosslinked via carbon-carbon bonds.

2. The crosslinked polymer system according to claim 1, wherein the number-average molecular weight of the thermoplastic elastomer is about 30,000 g / mol to about 400,000 g / mol.

3. The crosslinked polymer system according to claim 1 or claim 2, wherein the thermoplastic elastomer is a triblock copolymer comprising two polystyrene end blocks, and wherein the styrene content of the two polystyrene end blocks in the thermoplastic elastomer is from about 10% by weight to about 50% by weight.

4. The crosslinked polymer system according to any one of the preceding claims, wherein the thermoplastic elastomer comprises styrene-butadiene-styrene (SBS) or styrene / isoprene block copolymer (SIS).

5. The crosslinked polymer system according to any one of the preceding claims, wherein the thermoplastic elastomer copolymer is non-hydrogenated.

6. The crosslinked polymer system according to any one of the preceding claims, wherein the styrene / diene copolymer is partially hydrogenated.

7. The crosslinked polymer system according to any one of the preceding claims, wherein the crosslinked polymer system comprises silane crosslinking.

8. The crosslinked polymer system according to any one of the preceding claims, wherein the crosslinked polymer system is a thermoplastic vulcanized rubber.

9. The crosslinked polymer system according to any one of the preceding claims, further comprising an olefin polymer.

10. A peroxide-curable composition comprising: Thermoplastic elastomers containing vinyl aromatic monomer units and conjugated diene monomer units; Nitrile rubber; and A vulcanized package containing organic peroxides and silanes.

11. The peroxide vulcanizable composition of claim 10, wherein the peroxide vulcanizable composition comprises about 25% to about 95% by weight of the thermoplastic elastomer, or about 30% to about 85% by weight of the thermoplastic elastomer, or about 35% to about 75% by weight of the thermoplastic elastomer.

12. The peroxide-curable composition according to claim 10 or claim 11, wherein the peroxide-curable composition comprises about 15% to about 50% by weight of the nitrile rubber.

13. The peroxide-curable composition according to any one of claims 10-12, wherein the thermoplastic elastomer is selected from styrene-butadiene rubber, styrene-butadiene block copolymer, styrene-isoprene block copolymer, styrene-butadiene-isoprene rubber, styrene-butadiene / isoprene block copolymer, styrene-butadiene-isoprene block copolymer, and combinations thereof.

14. The peroxide vulcanizable composition according to any one of claims 10-13, wherein the thermoplastic elastomer is a triblock copolymer comprising two polystyrene end blocks, and wherein the styrene content of the two polystyrene end blocks in the thermoplastic elastomer is from about 10% by weight to about 50% by weight.

15. The peroxide-curable composition according to any one of claims 10-14, wherein the peroxide-curable composition comprises about 0.5% by weight to about 5% by weight of the silane.

16. The peroxide-curable composition according to any one of claims 10-15, wherein the silane comprises vinyltrimethoxysilane, vinyltriethoxysilane, or a combination thereof.

17. The peroxide-curable composition according to any one of claims 10-16, wherein the peroxide-curable composition comprises about 0.05% by weight to about 1% by weight of the organic peroxide.

18. The peroxide-curable composition according to any one of claims 10-17, wherein the organic peroxide comprises peroxyketal peroxide, ditert-alkyl peroxide, or a combination thereof.

19. The peroxide-curable composition of claim 18, wherein the ditert-alkyl peroxide comprises dicumyl peroxide.

20. The peroxide-curable composition according to any one of claims 8-17, further comprising an olefin polymer.

21. The peroxide-curable composition according to claim 20, wherein the olefin polymer is polypropylene.

22. The peroxide-curable composition according to any one of claims 10 to 21, further comprising oil.

23. A method for preparing the crosslinked polymer system of claim 1, the method comprising the following steps: Carbon-carbon crosslinked silane grafted blends are prepared by blending a thermoplastic elastomer containing repeating units derived from conjugated diene monomers, nitrile rubber, an organic peroxide, and a silane, such that the thermoplastic elastomer and the nitrile rubber contain carbon-carbon crosslinks and grafted silane moieties; and The carbon-carbon crosslinked silane grafted blend is extruded.

24. The method of claim 23, wherein the step of blending the thermoplastic elastomer, the organic peroxide, and the silane is carried out in the absence of a catalyst.

25. The method of claim 22 or claim 24, wherein the step of blending the thermoplastic elastomer, the organic peroxide, and the silane is carried out in the absence of moisture.

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