Thermoplastic vulcanizate gaskets for use in electrolytic cells

Abstract

An electrolytic cell is disclosed, which includes an electrolytic cell cell. The electrolytic cell cell includes a first spacer frame, a second spacer frame, and a first gasket having a first surface in contact with the first spacer frame and a second, opposing surface in contact with the second spacer frame. The first gasket includes a thermoplastic vulcanizate including a thermoplastic resin and an at least partially cured elastomer. The thermoplastic vulcanizate exhibits a Shore A hardness (ISO 868-85) of 35 to 100.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 435,842, filed December 29, 2022, and U.S. Provisional Patent Application No. 63 / 496,990, filed April 19, 2023, both of which are incorporated by reference in their entireties. [Background technology]

[0002] Electrolyzers utilize electrical energy to drive chemical reactions. A fuel, such as alkaline water, is supplied to an electrochemical cell within the electrolyzer, and the product hydrogen and oxygen gases are removed from the electrochemical cell. Electrolyzer systems typically include a stack of individual cells in electrical and fluid communication with one another. Each cell contains a number of components, such as electrodes, separators, frames, and gaskets, which are held in a specific orientation to allow for the necessary fluid flow and electrical communication between them. To maintain the desired orientation, spacers in the form of spacer plates or frames surrounding the active components are utilized. Additionally, gaskets are utilized for sealing purposes to prevent any liquid or gas leakage. Conventional gaskets are formed from rubber, such as silicone rubber, or fluoropolymer materials. While such materials can be molded into desired shapes, they are relatively difficult and expensive to mold to the precision shapes required to meet desired specifications and may not always provide the desired balance of properties. Summary of the Invention [Problem to be solved by the invention]

[0003]

[0003] Therefore, there is currently a need for gaskets that can be more easily incorporated into electrolytic cells. [Means for solving the problem]

[0004]

[0004] According to one embodiment of the present disclosure, an electrolytic cell is disclosed, which includes an electrolytic cell cell. The electrolytic cell cell includes a first spacer frame, a second spacer frame, and a first gasket having a first surface contacting the first spacer frame and a second, opposing surface contacting the second spacer frame. The first gasket includes a thermoplastic vulcanizate including a thermoplastic resin and an at least partially cured elastomer. The thermoplastic vulcanizate exhibits a Shore A hardness (ISO 868-85) of 35 to 100.

[0005]

[0005] Other features and aspects of the present disclosure are set forth in greater detail below.

[0006] 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 remainder of the specification, including reference to the accompanying drawings. [Brief explanation of the drawings]

[0006] [Figure 1]

[0007] FIG. 1 is a schematic diagram of one embodiment of an electrolyzer cell. [Figure 2]

[0008] FIG. 2 is a schematic diagram of one embodiment of an electrolyzer system. DETAILED DESCRIPTION OF THE INVENTION

[0007]

[0009] It will be understood by those skilled in the art that the discussion of the present invention is merely a description of exemplary embodiments and is not intended as a limitation on the broader aspects of the present disclosure.

[0010] Generally speaking, the present disclosure is directed to an electrolytic cell including a first spacer frame, a second spacer frame, and a gasket separating the first and second spacer frames, the gasket being formed from a thermoplastic vulcanizate ("TPV") that includes a thermoplastic resin and an at least partially cured elastomer. Typically, the gasket is positioned between the spacer frames, which can be pressed together. As a result, a gasket including a thermoplastic vulcanizate can be utilized to provide a seal sufficient to prevent leakage, e.g., of gas or liquid, to other components of the electrolytic cell.

[0008]

[0011] The present inventors have discovered that thermoplastic vulcanizates can provide desirable properties necessary to function as gaskets in electrolytic cells. For example, to function as a seal, the thermoplastic vulcanizate may exhibit a particular hardness. Specifically, the thermoplastic vulcanizate may exhibit a particular Shore A hardness (ISO 868-85; 15 seconds), which is used to measure the hardness of a thermoplastic vulcanizate and provides an indication of its resistance to indentation. In this regard, the thermoplastic vulcanizate may have a Shore A hardness of 35 to 100. For example, the thermoplastic vulcanizate may have a Shore A hardness of 35 or higher, such as 40 or higher, such as 45 or higher, such as 50 or higher, or such as 55 or higher. The thermoplastic vulcanizate may have a Shore A hardness of 100 or less, such as 95 or less, for example 90 or less, such as 80 or less, for example 70 or less, such as 65 or less, for example 60 or less, such as 55 or less, for example 50 or less. Such a hardness may enable the gasket to function effectively as a seal and provide the necessary compliance to conform to the desired shape between the spacer frames.

[0009]

[0012] Additionally, the thermoplastic vulcanizate may exhibit a particular strength as indicated by a particular mechanical property, for example, a 100% modulus (ASTM D412-16) of at least 0.3 MPa, e.g., 0.5 to 5 MPa, also referred to as the modulus at 100% elongation. For example, the 100% modulus may be 0.3 MPa or higher, such as 0.4 MPa or higher, for example 0.5 MPa or higher, for example 0.8 MPa or higher, for example 1 MPa or higher, such as 1.1 MPa or higher, for example 1.2 MPa or higher, such as 1.3 MPa or higher, for example 1.4 MPa or higher, for example 1.5 MPa or higher, such as 2 MPa or higher, for example 2.5 MPa or higher, for example 3 MPa or higher, such as 4 MPa or higher, for example 5 MPa or higher, for example 6 MPa or higher, such as 10 MPa or higher, for example 20 MPa or higher, for example 30 MPa or higher.The 100% modulus may be 50 MPa or less, such as 40 MPa or less, for example 30 MPa or less, such as 25 MPa or less, for example 20 MPa or less, such as 15 MPa or less, for example 10 MPa or less, for example 8 MPa or less, such as 6 MPa or less, for example 5 MPa or less, such as 4.5 MPa or less, for example 4 MPa or less, such as 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, such as 2.8 MPa or less, for example 2.5 MPa or less, for example 2.3 MPa or less, such as 2 MPa or less, for example 1.9 MPa or less, such as 1.8 MPa or less, for example 1.5 MPa or less, for example 1.3 MPa or less, such as 1.1 MPa or less, for example 0.8 MPa or less.

[0010]

[0013] The thermoplastic vulcanizates may also exhibit a tensile stress at break (i.e. strength) of 0.5 to 50 MPa, such as 1 to 20 MPa, for example 2 to 10 MPa. For example, the thermoplastic vulcanizates may exhibit a tensile stress of 0.5 MPa or higher, such as 1 MPa or higher, for example 1.5 MPa or higher, such as 2 MPa or higher, for example 2.5 MPa or higher, for example 3 MPa or higher, such as 3.5 MPa or higher, for example 4 MPa or higher, such as 5 MPa or higher, for example 6 MPa or higher, for example 7 MPa or higher, such as 10 MPa or higher, for example 15 MPa or higher, such as 20 MPa or higher, for example 30 MPa or higher, such as 40 MPa or higher, for example 50 MPa or higher, for example 60 MPa or higher, for example 70 MPa or higher. 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, such as 40 MPa or less, for example 30 MPa or less, such as 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, such as 11 MPa or less, for example 10 MPa or less, such as 9 MPa or less, for example 8 MPa or less, for example 7 MPa or less, such as 6.5 MPa or less, for example 6 MPa or less, such as 5.5 MPa or less, for example 5 MPa or less, such as 4.5 MPa or less, for example 4 MPa or less, such as 3.5 MPa or less, for example 3 MPa or less, such as 2.5 MPa or less. Tensile stress may be measured in accordance with ASTM D412-16 at a temperature of 23°C.

[0011]

[0014] The thermoplastic vulcanizate may also exhibit a desirable elongation at break. For example, the elongation at break may be 20% or higher, such as 40% or higher, for example 60% or higher, such as 80% or higher, for example 100% or higher, such as 200% or higher, for example 300% or higher, such as 400% or higher, for example 500% or higher, such as 550% or higher, for example 600% or higher, such as 650% or higher, for example 700% or higher, such as 750% or higher, or such as 900% or higher. The elongation at break may be 1500% or less, such as 1300% or less, for example 1000% or less, for example 800% or less, such as 600% or less, for example 500% or less, such as 450% or less, for example 400% or less, such as 350% or less, for example 300% or less. Elongation at break may be measured according to ASTM D412-16 at a temperature of 23°C.

[0012]

[0015] The thermoplastic vulcanizate may also exhibit a desirable ultimate tear strength. For example, the ultimate tear strength may be 1.5 MPa or higher, such as 2 MPa or higher, such as 2.5 MPa or higher, such as 2.7 MPa or higher, or such as 2.8 MPa or higher. The ultimate tear strength may be 10 MPa or less, such as 8 MPa or less, such as 6 MPa or less, such as 5 MPa or less, such as 4 MPa or less, such as 3.5 MPa or less, such as 3.3 MPa or less, such as 3.1 MPa or less, such as 3 MPa or less, such as 2.9 MPa or less, such as 2.8 MPa or less, or such as 2.7 MPa or less. Ultimate tear strength may be measured according to ASTM D624-00 at a temperature of 23°C.

[0013]

[0016] The thermoplastic vulcanizate can also be characterized by an advantageously low compression set. For example, the compression set can be 60% or less, for example 55% or less, for example 50% or less, for example 45% or less, for example 40% or less, for example 35% or less, for example 30% or less, for example 25% or less, for example 20% or less. The compression set can be 5% or more, for example 8% or more, for example 10% or more, for example 13% or more, for example 15% or more, for example 18% or more, for example 20% or more, for example 25% or more, for example 30% or more, for example 35% or more. The compression set can be measured according to ASTM D395B-18. Such aforesaid compression set may be after 22 hours at 70° C. In another embodiment, such aforesaid compression set may be after 70 hours at 125° C.

[0014]

[0017] The thermoplastic vulcanizate may also exhibit a relatively low coefficient of friction. For example, the coefficient of friction may be 3 or less, such as 2.8 or less, such as 2.5 or less, such as 2.2 or less, such as 2 or less, such as 1.8 or less, or such as 1.5 or less. The coefficient of friction may be greater than 1, such as 1.2 or more, such as 1.5 or more, such as 1.7 or more, such as 1.9 or more, such as 2 or more, or such as 2.2 or more. The coefficient of friction can be measured by pulling a weighted sled-like sample over a glass surface with a test distance of 200 mm and a test weight of 350 grams, where the coefficient of friction is the force required to pull the sled with the sample of material underneath.

[0015]

[0018] Various embodiments of the disclosure are described in more detail below. I. thermoplastic vulcanizate A. thermoplastic resin

[0019] As indicated above, thermoplastic vulcanizates contain one or more thermoplastic resins. In one embodiment, one thermoplastic resin can be utilized as the thermoplastic resin. In another embodiment, the thermoplastic resin comprises a mixture of thermoplastic resins. For example, more than one thermoplastic resin, for example, two or three thermoplastic resins, can be utilized in the thermoplastic vulcanizate. Furthermore, the thermoplastic resin can be a homopolymer or a copolymer. In one embodiment, the thermoplastic resin can be a homopolymer. In another embodiment, the thermoplastic resin can be a copolymer.

[0016]

[0020] Generally, any thermoplastic resin suitable for use in producing thermoplastic vulcanizates can be employed as the thermoplastic resin, such as polyolefins, polyimides, polyesters, polyamides, poly(phenylene ethers), polycarbonates, styrene-acrylonitrile copolymers, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polystyrene derivatives, polyphenylene oxide, polyoxymethylene, fluorine-containing thermoplastic resins, or mixtures thereof.

[0017]

[0021] In one embodiment, the thermoplastic resin may include at least a polyolefin. The polyolefin may be formed by polymerizing one or more alpha-olefins, such as, for example, ethylene, 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. Copolymers of ethylene and propylene, or copolymers of ethylene or propylene with another 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 mixtures thereof, may also be utilized in accordance with the present disclosure. In one embodiment, when the primary monomer is ethylene, the comonomer may be propylene or another C4-C8 alpha-olefin monomer. In one embodiment, the comonomer may be propylene. In another embodiment, the comonomer may be a C4-C8 alpha-olefin monomer. When the first monomer is propylene, the copolymer may be ethylene or another C4-C8 alpha-olefin monomer. In one embodiment, the comonomer may be ethylene. In another embodiment, the comonomer may be a C4-C8 alpha-olefin monomer.

[0018]

[0022] Other suitable polyolefin copolymers include copolymers of olefins and styrene, such as styrene-ethylene copolymers, or polymers of olefins and α,β-unsaturated acids or α,β-unsaturated esters, such as polyethylene-acrylic acid copolymers. Non-olefin thermoplastic resins include polymers and copolymers of styrene, α,β-unsaturated acids, α,β-unsaturated esters, and mixtures thereof. For example, polystyrene, polyacrylate, and polymethacrylate may be used.

[0019]

[0023] When the thermoplastic resin comprises a polyolefin copolymer formed with ethylene or propylene as the primary monomer, the corresponding comonomer may be present in an amount of 0.1 wt.% or more, such as 0.5 wt.% or more, for example 1 wt.% or more, for example 2 wt.% or more, for example 5 wt.% or more, for example 10 wt.% or more, for example 15 wt.% or more, for example 20 wt.% or more. The comonomer may be present in an amount of 40 wt.% or less, such as 30 wt.% or less, for example 25 wt.% or less, for example 20 wt.% or less, for example 15 wt.% or less, for example 10 wt.% or less, for example 8 wt.% or less, for example 6 wt.% or less, for example 5 wt.% or less. Similarly, the corresponding comonomer may be present in an amount of 0.1 mol.% or more, such as 0.5 mol.% or more, for example 1 mol.% or more, for example 2 mol.% or more, such as 5 mol.% or more, for example 10 mol.% or more, for example 15 mol.% or more, such as 20 mol.% or more. The comonomer may be present in an amount of 40 mol.% or less, such as 30 mol.% or less, for example 25 mol.% or less, for example 20 mol.% or less, such as 15 mol.% or less, for example 10 mol.% or less, for example 8 mol.% or less, for example 6 mol.% or less, for example 5 mol.% or less.

[0020]

[0024] In one embodiment, the polyolefin may be an ethylene polymer, a propylene polymer, or a mixture thereof. For example, in one embodiment, the ethylene polymer may be a polyethylene homopolymer. In another embodiment, the ethylene polymer may be a polyethylene copolymer. In one embodiment, the propylene polymer may be a polypropylene homopolymer. In another embodiment, the propylene polymer may be a polypropylene copolymer. Furthermore, the polypropylene polymer may be an isotactic or syndiotactic polypropylene. For example, in one embodiment, the polypropylene polymer may be an isotactic polypropylene. In another embodiment, the polypropylene polymer may be a syndiotactic polypropylene.

[0021]

[0025] These homopolymers and copolymers may be synthesized using any polymerization technique known in the art, including, but not limited to, Phillips catalysis, conventional Ziegler-Natta type polymerization, and metallocene catalysis, including, but not limited to, metallocene-alumoxane and metallocene-ionic activator catalysis. Thus, suitable catalyst systems include chiral metallocene catalyst systems, see, e.g., U.S. Pat. No. 5,441,920, and transition metal-face-centered lattice, heteroaryl ligand catalyst systems, see, e.g., U.S. Pat. No. 6,960,635.

[0022]

[0026] In one embodiment, the thermoplastic resin also includes a functionalized thermoplastic resin. In one embodiment, the functionalized thermoplastic resin may be present as a primary thermoplastic resin. In another embodiment, the functionalized thermoplastic resin may be present as a secondary thermoplastic resin, e.g., in a lesser amount than another thermoplastic resin in the thermoplastic vulcanizate.

[0023]

[0027] A functionalized thermoplastic resin may include a polymer containing at least one functional group. Such a functional group, sometimes referred to as a functional substituent or functional moiety, includes a heteroatom. In one or more embodiments, the functional group includes a polar group. Examples of polar groups include hydroxy, 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 obtained from reaction with maleic anhydride (e.g., polymerization or grafting), or a β-alkyl-substituted propanoic acid group or derivatives thereof.

[0024]

[0028] Generally, the thermoplastic resin may comprise a solid, generally high molecular weight polymeric material, and may have a Mw of about 50,000 g / mol or greater, such as 75,000 g / mol or greater, for example 100,000 g / mol or greater, for example 200,000 g / mol or greater, for example 300,000 g / mol or greater, for example 400,000 g / mol or greater, for example 500,000 g / mol or greater, for example 750,000 g / mol or greater, for example 1,000,000 g / mol or greater, for example 2,000,000 g / mol or greater, for example 3,000,000 g / mol or greater. 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, such as 700,000 g / mol or less. Further, the thermoplastic resin may have a Mn of about 50,000 g / mol or greater, such as 75,000 g / mol or greater, for example 100,000 g / mol or greater, such as 200,000 g / mol or greater, for example 300,000 g / mol or greater, such as 400,000 g / mol or greater, for example 500,000 g / mol or greater, such as 750,000 g / mol or greater, for example 1,000,000 g / mol or greater, such as 2,000,000 g / mol or greater, for example 3,000,000 g / mol or greater.Mn may be about 6,000,000 g / mol or less, for example 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.

[0025]

[0029] In one embodiment, the thermoplastic resin may be a crystalline polymer, or in another embodiment, a semi-crystalline polymer.For example, the crystallinity may be at least 25% by weight, for example at least 35%, for example at least 45%, for example at least 55%, for example at least 65%, for example at least 70%.Crystallinity can be determined by differential scanning calorimetry.For example, crystallinity can be determined by dividing the heat of fusion of a sample by the heat of fusion of a 100% crystalline polymer.

[0026]

[0030] The thermoplastic resin may also have a particular glass transition temperature ("Tg"). For example, the glass transition temperature may be relatively high. In this regard, the Tg may be about -120°C or higher, such as -110°C or higher, such as -100°C or higher, such as -90°C or higher, such as -70°C or higher, such as -50°C or higher, such as -30°C or higher, such as -25°C or higher, such as -20°C or higher, such as -15°C or higher, such as -10°C or higher, such as -5°C or higher. For example, it may be 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, for example, 100°C or higher, for example, 120°C or higher, for example, 140°C or higher, for example, 160°C or higher, for example, 180°C or higher, for example, 200°C or higher. The Tg may be about 300°C or less, such as 260°C or less, for example 220°C or less, for example 180°C or less, such as 140°C or less, for example 100°C or less, such as 80°C or less, for example 60°C or less, such as 40°C or less, for example 30°C or less, such as 20°C or less, for example 10°C or less, such as 5°C or less, for example 0°C or less, such as -5°C or less.

[0027]

[0031] In addition, a thermoplastic resin may have a particular melting point ("Tm"). For example, the melting point of a thermoplastic resin may be relatively high. Furthermore, the melting point of a thermoplastic resin may be lower than the decomposition temperature of the elastomer in the thermoplastic vulcanizate, which is generally characterized as the point at which molecular bonds begin to break or cleave such that the molecular weight of the elastomer begins to decrease. In this regard, the Tm may be about 100°C or higher, such as 120°C or higher, such as 140°C or higher, such as 150°C or higher, such as 160°C or higher, such as 170°C or higher, such as 180°C or higher, such as 190°C or higher, such as 200°C or higher, such as 240°C or higher, or such as 280°C or higher. The Tm may be about 400°C or less, such as 360°C or less, for example 320°C or less, such as 300°C or less, for example 280°C or less, such as 250°C or less, for example 220°C or less, such as 200°C or less, for example 180°C or less, such as 160°C or less.

[0028]

[0032] Thermoplastics can also be characterized as having a particular heat of fusion. For example, the heat of fusion may be about 0.1 J / g or higher, such as about 1 J / g or higher, for example about 2 J / g or higher, such as about 5 J / g or higher, for example about 10 J / g or higher, such as about 10 J / g or higher, for example about 30 J / g or higher, such as 40 J / g or higher, for example 50 J / g or higher, such as 60 J / g or higher, for example 70 J / g or higher, such as 100 J / g or higher, for example 120 J / g or higher, such as 140 J / g or higher, for example 160 J / g or higher, such as 180 J / g or higher, for example 200 J / g or higher. 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, such as about 200 J / g or less, for example about 180 J / g or less, such as about 150 J / g or less, for example about 120 J / g or less, such as about 100 J / g or less, for example about 80 J / g or less, such as 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, such as about 20 J / g or less.

[0029]

[0033] The thermoplastic resin may have a melt flow rate of up to 400 g / 10 min. Generally, a thermoplastic resin may 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 may be 0.1 g / 10 min or higher, for example, 0.2 g / 10 min or higher, for example, 0.3 g / 10 min or higher, for example, 0.4 g / 10 min or higher, for example, 0.5 g / 10 min or higher. The melt flow rate is a measure of how easily a polymer flows under standard pressure and is measured using ASTM D-1238 at 190°C and a load of 2.16 kg.

[0030]

[0034] The thermoplastic vulcanizate may generally comprise about 10 wt.% or more, for example, about 15 wt.% or more, for example, about 20 wt.% or more, for example, about 25 wt.% or more, for example, about 30 wt.% or more, for example, about 35 wt.% or more, for example, about 40 wt.% or more, for example, about 50 wt.% or more, for example, about 60 wt.% or more of a thermoplastic resin. The thermoplastic vulcanizate may comprise about 90 wt.% or less, for example, about 80 wt.% or less, for example, about 70 wt.% or less, for example, about 60 wt.% or less, for example, about 50 wt.% or less, for example, about 40 wt.% or less of a thermoplastic resin. In another embodiment, such a weight percentage may be based on the total weight of the thermoplastic resin and elastomer combined within the thermoplastic vulcanizate.

[0031] B. Elastomer

[0035] As indicated above, the thermoplastic vulcanizate contains an elastomer. Generally, any elastomer suitable for use in manufacturing TPVs can be utilized in accordance with the present disclosure. In one embodiment, one elastomer can be utilized as the elastomer. In other embodiments, the elastomer can comprise a mixture of elastomers. For example, more than one elastomer, such as two or three elastomers, can be utilized in the thermoplastic vulcanizate.

[0032]

[0036] Any elastomer or mixture thereof capable of being vulcanized (crosslinked or cured) can be used as an elastomer (sometimes referred to herein as rubber). Reference to rubber or elastomer can include mixtures of more than one type. Useful elastomers typically contain some degree of unsaturation in their polymer backbone. 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.

[0033]

[0037] Vulcanizable elastomers include polyolefin copolymer elastomers. These copolymers are made from ethylene and one or more higher alpha olefins, including, but not limited to, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, or a combination thereof, and may further include one or more copolymerizable multiply unsaturated comonomers, such as diolefins or diene monomers. The alpha olefin may be propylene, 1-hexene, 1-octene, or a combination thereof. These rubbers may lack substantial crystallinity and may preferably be amorphous copolymers.

[0034]

[0038] Diene monomers include, but are 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 combinations thereof. The diene monomer may be 5-ethylidene-2-norbornene and / or 5-vinyl-2-norbornene. When a copolymer is prepared from ethylene, an alpha olefin, and a diene monomer, the copolymer may be referred to as a terpolymer (EPDM rubber), or when multiple alpha olefins, dienes, or both are used, it may be referred to as a tetrapolymer (EAODM rubber).

[0035]

[0039] In one embodiment, the polyolefin elastomeric copolymer can include an ethylene acrylic copolymer (also referred to as an ethylene-acrylate copolymer). The ethylene acrylic copolymer can be represented by (i) Formula (A):

[0036] [ka]

[0037] (In the formula, R 1 is hydrogen or C1-C 12 alkyl, and R 2 is C1~C 12 Alkyl, C1-C 20 Alkoxyalkyl, C1-C 12 Cyanoalkyl, or C1-C 12 The ethylene acrylic copolymer may also optionally contain copolymerized units of (iii) an unsaturated carboxylic acid or anhydride thereof.

[0038]

[0040] The ethylene acrylic copolymer may be amorphous. The term "amorphous" generally refers to a copolymer that exhibits little crystalline structure at room temperature under unstressed conditions. Alternatively, the amorphous material may have a heat of fusion of less than 4 J / g, as determined according to ASTM D3418-08.

[0039]

[0041] As indicated above, the ethylene acrylic copolymer comprises copolymerized units (i) of a monomer of formula (A). Such a monomer may be an alkyl ester or alkoxyalkyl ester of a propenoic acid. In this regard, the ethylene acrylic copolymer may include an alkyl ester or alkoxyalkyl ester of a propenoic acid along with a cure site monomer and an ethylene monomer. Examples of suitable alkyl and alkoxyalkyl esters of propenoic acid include alkyl acrylates and alkoxyalkyl acrylates, as well as alkyl acrylates in which the propenoic acid is C1-C2. 12Included are alkyl group substituted monomers, such as alkyl methacrylates, alkyl ethacrylates, alkyl propacrylates, alkyl hexacrylates, alkoxyalkyl methacrylates, alkoxyalkyl ethacrylates, alkoxyalkyl propacrylates, alkoxyalkyl hexaacrylates, and any combination thereof.

[0040]

[0042] Alkyl and alkoxyalkyl esters of propenoic and substituted propenoic acids are C1-C alkyl esters of acrylic or methacrylic acid. 12 Alkyl esters or C1-C of acrylic or methacrylic acid 20 The ester group may be an alkoxyalkyl ester. Examples include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-(n-propoxy)ethyl acrylate, 2(n-butoxy)ethyl acrylate, 3-methoxypropyl acrylate, 3-ethoxypropyl acrylate, and mixtures thereof. The ester group may contain a branched or unbranched C1-C8 alkyl group or an unbranched C1-C4 alkyl group. Specific examples include alkyl (meth)acrylate esters, such as methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, and mixtures thereof.

[0041]

[0043] The polymerized units of the monomer of formula (A) may be present in an amount ranging from about 20% or more, for example, about 30% or more, for example, about 40% or more, for example, about 45% or more, for example, about 50% or more, to about 75% or less, for example, about 70% or less, for example, about 65% or less, based on the weight of the ethylene acrylic copolymer. For example, the polymerized units of the monomer of formula (A), such as a propenoic acid ester comonomer, may be present in an amount ranging from about 45% or about 50% to about 70% based on the weight of the ethylene acrylic copolymer. In some examples, the concentration of polymerized units of the monomer of formula (A), such as a propenoic acid ester comonomer, may be in the range of about 55% to about 70% based on the weight of the ethylene acrylic copolymer. Also, as is commonly understood, polymerized units of a monomer of formula (A) may include a first monomer of formula (A) and a second monomer of formula (A), where the combination of monomers is present in the weight percentages set forth above.

[0042]

[0044] In addition to containing polymerized units of the monomer of formula (A), the ethylene acrylic copolymer contains copolymerized units of ethylene, which may constitute the remaining weight percent of the ethylene acrylic copolymer after taking into account the copolymerized units of the monomer of formula (A) and the copolymerized units of any other monomers, such as optional copolymerized units of an unsaturated carboxylic acid or anhydride. For example, the copolymerized units of ethylene may be present in an amount ranging from about 10% or more, such as about 15% or more, for example, about 20% or more, for example, about 25% or more, for example, about 28% or more, for example, about 30% or more, for example, about 35% or more, for example, about 40% or more, to about 65% or less, for example, about 60% or less, for example, about 58% or less, for example, about 55% or less, for example, about 50% or less, for example, about 45% or less, for example, about 40% or less, based on the weight of the ethylene acrylic copolymer. The copolymerized units of ethylene may make up the remainder of the weight percent attributable to copolymerized units of the monomer of Formula (A) and, if present, copolymerized units of the unsaturated carboxylic acid or anhydride thereof.

[0043]

[0045] In addition to containing polymerized units of the monomer of formula (A) and copolymerized units of ethylene, the ethylene acrylic copolymer may further contain a copolymerized cure site monomer, such as a carboxylic acid, its anhydride, or any mixture of acids and acid anhydrides. Suitable unsaturated carboxylic acids include acrylic acid, methacrylic acid, 1,4-butenedioic acid, citraconic acid, monoalkyl esters of 1,4-butenedioic acid, and mixtures thereof. The 1,4-butenedioic acid may be present in the cis or trans form or both (e.g., maleic acid or fumaric acid) prior to polymerization. Suitable cure site comonomers also include anhydrides of unsaturated carboxylic acids, such as maleic anhydride, citraconic anhydride, itaconic anhydride, and mixtures thereof. Cure site monomers can include maleic acid and either its half-acid esters (monoesters) or diesters, such as methyl or ethyl half-acid esters (e.g., monoethyl maleate); fumaric acid and either its half-acid esters or diesters, such as methyl, ethyl, or butyl half-acid esters; and monoalkyl and monoarylalkyl esters of itaconic acid. The cure site monomers can, in some examples, be present in an amount ranging from about 0.5% or more, such as about 1% or more, such as about 1.5% or more, such as about 2% or more, to about 10% or less, such as about 8% or less, such as about 6% or less, such as about 5% or less, such as about 4% or less, such as about 3% or less, based on the weight of the ethylene acrylic copolymer, for example, from about 2% to about 5%, such as from about 2% to about 4%, based on the weight of the ethylene acrylic copolymer.

[0044]

[0046] The ethylene acrylic copolymer may consist essentially of, or may consist of, copolymerized units of a monomer of formula (A), copolymerized units of ethylene, and optionally copolymerized units of an unsaturated carboxylic acid or anhydride. In another embodiment, the ethylene acrylic copolymer may consist essentially of, or may consist of copolymerized units of a monomer of formula (A), copolymerized units of ethylene, and copolymerized units of an unsaturated carboxylic acid or anhydride. In this context, "consisting essentially of" refers to an ethylene acrylic copolymer that does not substantially reduce the elastomeric properties of the ethylene acrylic copolymer when the copolymer consists solely of those copolymerized units.

[0045]

[0047] One specific example of an ethylene acrylic copolymer includes (i) methyl acrylate, butyl acrylate, or any combination thereof, present in an amount ranging from about 50% to about 70% by weight of the ethylene acrylic copolymer; (ii) ethylene making up the remaining weight percent of the ethylene acrylic copolymer; and (iii) a copolymer of a cure site monomer having carboxylic acid functionality, present in an amount ranging from about 2% to about 5% (e.g., 2% to 4%) by weight of the ethylene acrylic copolymer.

[0046]

[0048] Unless otherwise specified herein, elastomers that are polyolefin elastomeric copolymers may contain from about 15 to about 90 mole percent ethylene units derived from ethylene monomers, from about 40 to about 85 mole percent, or from about 50 to about 80 mole percent ethylene units. The copolymers may contain from about 10 to about 85 mole percent, from about 15 to about 50 mole percent, or from about 20 to about 40 mole percent alpha-olefin units derived from alpha-olefin monomers. The aforementioned mole percentages are based on the total moles of mer units in the polymer. If the copolymer contains diene units, the copolymer may contain from 0.1 to about 14 weight percent, from about 0.2 to about 13 weight percent, or from about 1 to about 12 weight percent of units derived from diene monomers. The weight percent of diene units derived from a diene can be determined according to ASTM D-6047. In some cases, the copolymer contains less than 5.5 weight percent, such as less than 5.0 weight percent, such as less than 4.5 weight percent, such as less than 4.0 weight percent, of units derived from diene monomers. In still other cases, the copolymer contains more than 6.0 weight percent, such as more than 6.2 weight percent, such as more than 6.5 weight percent, such as more than 7.0 weight percent, such as more than 8.0 weight percent, of units derived from diene monomers.

[0047]

[0049] Polyolefin elastomeric copolymers can be obtained using polymerization techniques known in the art, such as conventional solution or slurry polymerization processes. For example, catalysts employed to polymerize ethylene, alpha-olefins, and diene monomers into the elastomeric copolymers can include both conventional Ziegler-Natta-type catalyst systems, particularly those containing titanium and vanadium compounds, and metallocene catalysts, such as Group 3-6 (titanium, zirconium, and hafnium) metallocene catalysts, particularly bridged mono- or biscyclopentadienyl metallocene catalysts. Other catalyst systems, such as Brookhart catalyst systems, can also be employed.

[0048]

[0050] In one embodiment, the elastomer can include butyl rubber. For example, butyl rubber can include 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, such as in the case of chlorinated and brominated butyl rubber. In one or more embodiments, these halogenated polymers can be derived from monomers such as parabromomethylstyrene.

[0049]

[0051] 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 with parabromomethylstyrene mer units). These copolymers and terpolymers may be halogenated. Additionally, butyl rubber may be prepared by polymerization at low temperatures in the presence of Friedel-Crafts catalysts using techniques known in the art.

[0050]

[0052] In one embodiment, when the butyl rubber comprises an isobutylene-isoprene copolymer, the copolymer may contain from about 0.5 to about 30, or from about 0.8 to about 5 weight percent isoprene, based on the total weight of the copolymer, with the remainder being isobutylene.

[0051]

[0053] In another embodiment, when the butyl rubber comprises an isobutylene-paramethylstyrene copolymer, the copolymer may contain from about 0.5 to about 25, or from about 2 to about 20 weight percent 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]

[0054] In other embodiments, when the butyl rubber comprises isobutylene-isoprene-divinylstyrene, the terpolymer may comprise from about 95 to about 99, or from about 96 to about 98.5 weight percent isobutylene, and from about 0.5 to about 5, or from about 0.8 to about 2.5 weight percent isoprene, based on the total weight of the terpolymer, with the remainder being divinylstyrene.

[0053]

[0055] In the case of halogenated butyl rubber, the butyl rubber may contain from about 0.1 to about 10, or from about 0.3 to about 7, or from about 0.5 to about 3 weight percent halogen, based on the total weight of the copolymer or terpolymer.

[0054]

[0056] 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. The Mooney viscosity (ML at 125° C.) of the butyl rubber may also be less than about −55° C., or less than about −58° C., or less than about −60° C., or less than about −63° C. 1+8 ) may be about 25 to about 75, or about 30 to about 60, or about 40 to about 55.

[0055]

[0057] Generally, the elastomer, particularly the polyolefin elastomeric copolymer, may have a Mw of about 50,000 g / mol or greater, such as 75,000 g / mol or greater, for example 100,000 g / mol or greater, such as 200,000 g / mol or greater, for example 300,000 g / mol or greater, such as 400,000 g / mol or greater, for example 500,000 g / mol or greater, such as 750,000 g / mol or greater, for example 1,000,000 g / mol or greater. 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 an Mn of about 50,000 g / mol or greater, such as 75,000 g / mol or greater, for example 100,000 g / mol or greater, such as 200,000 g / mol or greater, for example 300,000 g / mol or greater, such as 400,000 g / mol or greater, for example 500,000 g / mol or greater, such as 750,000 g / mol or greater, for example 1,000,000 g / mol or greater.Mn may be about 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, 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]

[0058] Thermoplastic vulcanizates may generally contain about 2 wt.% or more elastomer, such as about 5 wt.% or more, for example about 10 wt.% or more, such as about 15 wt.% or more, for example about 20 wt.% or more, such as about 25 wt.% or more, for example about 30 wt.% or more, such as about 40 wt.% or more, for example about 50 wt.% or more elastomer. The thermoplastic vulcanizate may comprise about 90 wt.% or less of elastomer, such as about 80 wt.% or less, for example about 70 wt.% or less, for example about 60 wt.% or less, for example about 50 wt.% or less, for example about 40 wt.% or less, for example about 35 wt.% or less, for example about 30 wt.% or less, for example about 25 wt.% or less, for example about 20 wt.% or less, for example about 15 wt.% or less of elastomer. In another embodiment, such aforesaid weight percentages may be based on the total weight of the thermoplastic resin and elastomer combined within the thermoplastic vulcanizate.

[0057]

[0059] Furthermore, when a mixture of elastomers is present, the primary elastomer may be present in an amount of about 60 wt.% or more, such as about 70 wt.% or more, for example about 80 wt.% or more, for example about 90 wt.% or more, or less than 100 wt.%, based on the weight of the elastomer. The secondary elastomer may be present in an amount of 40 wt.% or less, such as 30 wt.% or less, for example 20 wt.% or less, for example 15 wt.% or less, such as 10 wt.% or less, for example 5 wt.% or less, to greater than 0 wt.% elastomer.

[0058] C. curable composition

[0060] As provided herein, TPV formulations, and particularly the elastomers within the formulations, may undergo dynamic vulcanization, in which the elastomer is at least partially cured. Generally, any curing agent capable of curing or crosslinking an elastomer may be used. Some non-limiting examples of these curing agents include phenolic resins, peroxides, maleimides, and silicon-containing curing agents. The curing agent may be used with one or more coagents that serve as initiators, catalysts, etc., for the purpose of improving the overall state of cure of the elastomer. For example, the curable composition of some embodiments includes one or both of zinc oxide (ZnO) and stannous chloride (SnCl).

[0059]

[0061] Generally, phenolic resins are not necessarily limited. For example, they can include resole resins made by condensing alkyl-substituted or unsubstituted phenols with aldehydes such as formaldehyde in an alkaline medium, or by condensing difunctional phenol dialcohols. The alkyl substituents of the alkyl-substituted phenols typically contain 1 to about 10 carbon atoms. Dimethylolphenols or phenolic resins substituted in the para position with alkyl groups containing 1 to about 10 carbon atoms can be used. These phenolic curing agents can be thermosetting resins and are sometimes referred to as phenolic resin curing agents or phenolic resins. These phenolic resins are ideally suited for use with catalyst systems. For example, non-halogenated phenolic curing resins are used 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.

[0060]

[0062] 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.In addition, diaryl peroxides, ketone peroxides, peroxydicarbonates, peroxyesters, dialkyl peroxides, hydroperoxides, peroxyketals, and mixtures thereof can also be used.

[0061]

[0063] 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.

[0062]

[0064] As mentioned above, hydrosilylation curing can be carried out in the presence of a catalyst, including, but not limited to, peroxide catalysts and catalysts containing Group VIII transition metals, including, but not limited to, palladium, rhodium, and platinum, as well as complexes of these metals.

[0063]

[0065] In certain embodiments, the curable composition also includes one or both of ZnO and SnCl. In one embodiment, the curable composition may include zinc oxide. In another embodiment, the curable composition may include stannous chloride. In a further embodiment, the curable composition may include zinc oxide and stannous chloride.

[0064]

[0066] Coagents may also be employed with curing agents such as phenolic resins and / or peroxides. Coagents can include polyfunctional acrylic esters, polyfunctional methacrylic esters, or combinations thereof. In other words, the coagent contains two or more organic acrylic or methacrylic acid substituents. Examples of polyfunctional 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 combinations 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. Coagents also include triallyl cyanurate, triallyl isocyanurate, triallyl phosphate, sulfur, N-phenylbismaleamide, zinc diacrylate, zinc dimethacrylate, divinylbenzene, 1,2-polybutadiene, trimethylolpropane trimethacrylate, tetramethylene glycol diacrylate, trifunctional acrylic esters, dipentaerythritol pentaacrylate, multifunctional acrylates, delayed cyclohexanedimethanol diacrylate esters, multifunctional methacrylates, metal acrylic and methacrylic acid salts, oximers such as quinone dioximes, and the like.

[0065]

[0067] Additionally, oils may be employed in the hardening system. Oils may also be referred to as process oils, extender oils, or plasticizers. Useful oils include mineral oils, synthetic process oils, or combinations thereof, which may act as plasticizers. Plasticizers include, but are not limited to, aromatic oils, naphthenic oils, and extender oils. Exemplary synthetic process 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 mono- or diesters, or alternatively, oligomeric aliphatic esters or alkyl ether esters.

[0066]

[0068] The curable composition may be added at one or more locations, such as the feed hopper of a melt-mixing extruder. In some embodiments, the curative and any additional coagents may be added together to the TPV formulation; in other embodiments, one or more coagents may be added to the TPV formulation at a different time than any one or more of the curatives while the TPV formulation is being processed to form the TPV.

[0067]

[0069] 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.

[0068] D. Other additives

[0070] The thermoplastic vulcanizate formulations of some embodiments may optionally further comprise 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 may also comprise one or more of such additives.

[0069]

[0071] In some embodiments, any suitable processing oil may be included. In certain embodiments, the processing oil can be selected from (i) extending oil, which is the oil present in the oil-extended rubber (e.g., the oil present with the elastomer); (ii) free oil, which is the oil added during the vulcanization process (separate from any other TPV formulation components, such as the elastomer or thermoplastic vulcanizate); (iii) curative oil, which is the oil used to dissolve / disperse the curative, for example, a curative-in-oil dispersion, e.g., a phenolic resin in oil (thus, in such embodiments, the curable composition can be present in the TPV formulation as a curative-in-oil additive); and (iv) any combination of the foregoing oils (i)-(iii). Thus, the processing oil may be present in the TPV formulation as part of another component (e.g., as part of the elastomer, such that the elastomer includes the elastomer and the extending oil, if the processing oil is an extending oil; or as part of the curable composition, such that the curable composition includes the curable oil and the curing agent, if the processing oil is a carrier for the curing agent in oil). Alternatively, the processing oil may be added to the TPV separately from the other components, i.e., as free oil.

[0070]

[0072] The extending oil, free oil, and / or hydrogenated oil may be the same oil or different oils in various embodiments. Process oils may include one or more of (i) "refined" or "mineral" oils, and (ii) synthetic oils. As used herein, mineral oil refers to oils of lubricating viscosity (i.e., 1 mm), obtained from petroleum crude oil and subjected to one or more refining and / or hydroprocessing steps (e.g., fractionation, hydrocracking, dewaxing, isomerization, and hydrofinishing) to refine and chemically modify the components to achieve a final set of properties. 2 "Refined" oils refer to any hydrocarbon liquid having a kinematic viscosity at 100°C (kinematic viscosity at 100°C / s or higher). 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.

[0071]

[0073] Generally, refined or synthetic process oils according to some embodiments include, but are not limited to, any one or more of aromatic oils, naphthenic oils, and paraffinic oils. Exemplary synthetic process oils are polylinear alphaolefins, polybranched alphaolefins, and hydrogenated polyalphaolefins. The compositions of some embodiments of this invention may also include organic esters, alkyl ethers, or combinations thereof.

[0072]

[0074] In certain embodiments, at least a portion of the process oil (for example, all or a portion of any one or more of the extended oil, free oil, and / or hydrogenated oil) is a low aromatic / sulfur oil, and (i) has 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 that portion of the process oil; and (ii) has a sulfur content of less than 0.3 wt.%, or less than 0.003 wt.%, based on the weight of that portion of the process oil. The aromatic content can be determined in a manner consistent with 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. As used herein, the percentage of aromatic carbon is the ratio (percentage) of the number of aromatic carbon atoms to the number of all carbon atoms, as determined by a method according to ASTM D2140.

[0073]

[0075] Suitable process oils of certain embodiments can 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, which is incorporated herein by reference.

[0074]

[0076] The TPV formulations of some embodiments may also include, or alternatively include, polymer processing additives. The processing additives employed in such embodiments are polymeric resins with very high melt flow indices. These polymeric 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 or 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 specified. A preferred linear polymer processing additive is polypropylene homopolymer. A preferred branched polymer processing additive includes diene-modified polypropylene polymer.

[0075]

[0077] In addition, the formulation may also contain reinforcing and / or non-reinforcing fillers. Suitable fillers and extenders include traditional inorganic materials such as calcium carbonate, clay, silica, talc, and titanium dioxide, as well as organic materials such as carbon black, graphene, and organic and inorganic nanoscale fillers. In one embodiment, the filler may include graphene. Graphene may be monolayer or multilayer (i.e., graphite). For example, graphene may be multilayer, such as bilayer graphene, trilayer graphene, or a mixture thereof. Graphene may be pristine graphene or CVD graphene. Graphene also includes graphene nanoplatelets, e.g., those having thicknesses of 1 nm to 3 nm and / or lateral dimensions of 100 nm to 100 μm. Furthermore, graphene may be modified. For example, graphene may be oxidized (graphene oxide), reduced graphene oxide, or functionalized graphene oxide. The foregoing types may be further defined in accordance with ISO / TS8004-13:2017. Additionally, the manner in which graphene may be provided is not limited. For example, graphene may be added in powder form, pre-compressed form, and / or via a masterbatch.

[0076]

[0078] In certain embodiments, the TPV formulation may include an acid scavenger. These acid scavengers may 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 formula: MgAl(OH) 16 CO3·4H2O. Synthetic hydrotalcite compounds have the formula: Mg4.3 Al2(OH) 12 6CO3 mH2O or Mg 4.5 Al2(OH) 13 It may have CO3·3.5H2O.

[0077]

[0079] These additives can be utilized in amounts that provide the desired effect. In this regard, the additives may be present in an amount up to about 50 weight percent of the total TPV formulation or 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, such as 0.1 wt.% or more, for example 0.2 wt.% or more, such as 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, such as 10 wt.% or more, for example 12 wt.% or more, such as 15 wt.% or more, for example 20 wt.% or more, for example 25 wt.% or more, such as 30 wt.% or more. They may be present in an amount of 50 wt.% or less, for example, 40 wt.% or less, for example, 30 wt.% or less, for example, 25 wt.% or less, for example, 20 wt.% or less, for example, 18 wt.% or less, for example, 15 wt.% or less, for example, 13 wt.% or less, for example, 10 wt.% or less, for example, 8 wt.% or less, for example, 6 wt.% or less, for example, 4 wt.% or less, for example, 3 wt.% or less, for example, 2 wt.% or less, for example, 1 wt.% or less, for example, 0.5 wt.% or less. In another embodiment, such a percentage may be based on the weight of the thermoplastic resin. In a further embodiment, such a percentage may be based on the weight of the elastomer. In still further embodiments, such aforesaid percentages may be based on the combined weight of the thermoplastic resin and elastomer.

[0078] E. TPV formulation

[0080] Generally, as used herein, "TPV formulation" refers to a mixture of components blended or otherwise brought together prior to or during processing of the TPV formulation to form a TPV. This is in recognition of the fact 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.

[0079]

[0081] Generally, TPV formulations according to various embodiments include an elastomer, a thermoplastic resin, and a curing agent (or curable 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 or after dynamic vulcanization.

[0080]

[0082] The relative amounts of the various components in a TPV formulation are best characterized based on the amount of elastomer in the formulation, specifically in 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 most commercially available elastomers such as EPDM, the phr amount is based solely on the amount of elastomer, excluding the 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 to be 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 thermoplastic resin, the formulation would contain 50 parts by weight of thermoplastic resin in addition to 100 parts by weight of elastomer and 75 parts by weight of extending oil.

[0081]

[0083] The TPV formulations of some embodiments may include the thermoplastic resin in an amount of about 20 to about 300 parts by weight per 100 parts elastomer or rubber (phr). In various embodiments, the thermoplastic resin is included in the TPV formulation in an amount ranging from a lower limit of about any one of 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 165, 170, and 175 phr, to an upper limit of about any one of 100, 125, 150, 175, 200, 225, 250, 275, and 300 phr. The thermoplastic resin may be present in an amount ranging from any of the foregoing lower limits to any of the foregoing upper limits, provided that the upper limit is greater than or equal to the lower limit. In certain embodiments, increasing the amount of thermoplastic resin corresponds to increasing the hardness of the dynamically vulcanized TPV.

[0082]

[0084] When the elastomer consists solely of elastomer, the elastomer is, by definition, present at 100 phr (as it is based on phr notation). However, in embodiments in which the elastomeric element includes ingredients other than elastomer, such as an extender oil, the elastomer may be present in the TPV formulation in an amount ranging from a lower limit of about any one of 100.05, 100.1, 100.15, 100.2, 105, 110, 115, and 120 phr to an upper limit of about any one of 110, 120, 125, 150, 175, 200, 225, and 250 phr.

[0083]

[0085] As previously mentioned, the TPV formulations of certain embodiments may optionally include additional TPV additives. The amount of additional additive is added in addition to any additives already included in other components of the TPV formulation. For example, any additives, such as extender oil, included with the elastomer are already accounted for as part of the amount of elastomer added to the formulation; therefore, the recited amount of additional additives excludes any additives already included with the elastomer. The additional additives may be present in the TPV formulation in a total amount ranging from about 0 phr to about 300 phr. In certain embodiments, the additional additives may be present in the TPV in a total amount ranging from a lower limit of about 0, 5, 10, 15, 25, 30, 40, 50, 60, 70, 80, 90, and 100 phr to an upper limit of about 25, 30, 40, 50, 60, 80, 100, 125, 150, 175, 200, 225, 250, 275, and 300 phr. The additional additives may be present in a total amount ranging from any one of the foregoing lower limits to any one of the foregoing upper limits, provided that the upper limit is greater than or equal to the lower limit. In one embodiment, such foregoing phr may refer to the additional additives individually, rather than in total.

[0084]

[0086] For convenience, the components of the TPV formulations of various embodiments can alternatively be characterized based on their weight percentage in the TPV formulation according to the following.

[0087] The thermoplastic resin may be present in the TPV formulation in an amount ranging from a lower limit of any one of about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, and 25 wt. % to an upper limit of any one of about 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, and 60 wt. %, where the upper limit is greater than or equal to the lower limit.

[0085]

[0088] The elastomer may be present in the TPV formulation in an amount ranging from a lower limit of any one of about 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, and 35 wt. % to an upper limit of any one of about 35, 40, 45, 50, 55, 60, 65, 70, 75, and 80 wt. %, provided that the upper limit is greater than or equal to the lower limit, and the elastomer is present in the TPV formulation in a range of from about 20 to about 300 phr.

[0086]

[0089] The optional additional TPV additives may be present in the TPV formulation in a total amount ranging from a lower limit of about any one of 0, 5, 10, 15, 20, 25, 30, 35, and 40 wt. % to an upper limit of about any one of 30, 35, 40, 45, 50, 55, 60, and 65 wt. %, provided that the upper limit is greater than or equal to the lower limit, and the additive is present in the TPV formulation in a range of about 0 to about 300 phr.

[0087] F. Processing of TPV compounds

[0090] The thermoplastic vulcanizates of the present disclosure are prepared by dynamic vulcanization techniques. The term "dynamic vulcanization" refers to the vulcanization or curing process for TPV formulations containing elastomers, in which the elastomer is vulcanized under high-shear mixing conditions at temperatures above the melting point of the thermoplastic resin to produce a thermoplastic vulcanizate. In dynamic vulcanization, the elastomer is simultaneously crosslinked and dispersed as fine particles within the thermoplastic resin or matrix, although other morphologies, such as co-continuous morphologies, may exist depending on the degree of cure, the viscosity ratio of the elastomer to the resin, the intensity of mixing, the residence time, and the temperature.

[0088]

[0091] In some embodiments, processing may include melt-blending a TPV formulation including an elastomer, a thermoplastic resin, and a curative in a chamber. The chamber may be any vessel suitable for blending the selected compositions under the temperature and shear conditions necessary to form a thermoplastic vulcanizate. In this regard, the chamber may be a mixer, such as a Banbury™ mixer. TM ) mixer or Brabender (trademark) TM) mixers, as well as certain mixing extruders, such as co-rotating, counter-rotating, and twin-screw extruders, as well as co-kneaders, such as Buss® kneaders. According to one embodiment, the chamber is an extruder, which may be a single or multi-screw extruder. The term "multi-screw extruder" refers to an extruder having two or more screws, with two- and three-screw extruders being exemplary, and in some embodiments, two-screw or twin-screw extruders being preferred. The extruder screws may have multiple lobes, with two- and three-lobe screws being preferred. It will be readily understood that other screw designs can be selected according to the methods of embodiments of the present disclosure. In some embodiments, dynamic vulcanization may occur during and / or as a result of extrusion. After exiting the mixer, the blend containing the vulcanized rubber and thermoplastic may be ground, chopped, extruded, pelletized, injection molded, or processed by any other desired technique.

[0089]

[0092] Dynamic vulcanization of elastomers may be carried out to achieve relatively high shear. In certain embodiments, blending may be carried out at temperatures not exceeding about 400°C, preferably not exceeding about 300°C, and more preferably not exceeding about 250°C. The minimum temperature at which melt blending is carried out is generally greater than or equal to about 130°C, preferably greater than or equal to about 150°C, and more particularly greater than about 180°C. Blending times are selected by considering the nature of the compounds used in the TPV formulation and the blending temperature. Times generally vary from about 5 seconds to about 120 minutes, and in most cases are from about 10 seconds to about 30 minutes.

[0090]

[0093] In some embodiments, dynamic vulcanization may involve phase transition. As those skilled in the art will recognize, dynamic vulcanization can be initiated by having a rubber with a volume fraction greater than that of the thermoplastic resin. Thus, the thermoplastic resin may exist as a discontinuous phase when the volume fraction of the rubber is greater than that of the thermoplastic resin. As dynamic vulcanization progresses, the viscosity of the rubber increases, and a phase transition occurs under dynamic mixing. In other words, upon phase transition, the thermoplastic resin phase becomes a continuous phase.

[0091]

[0094] Other additives are preferably present in the TPV formulation when dynamic vulcanization occurs; however, in some embodiments, one or more other additives (if present) may be added to the composition after cure and / or phase transition (e.g., after the processing portion of dynamic vulcanization). Additional additives may be included after dynamic vulcanization by employing various techniques. In one embodiment, additional additives may be added while the thermoplastic vulcanizate remains in a molten state from the dynamic vulcanization process. For example, additional additives may be added downstream of the dynamic vulcanization configuration in a process employing continuous processing equipment such as a single or twin screw extruder. In other embodiments, the thermoplastic vulcanizate may be "worked-up" or pelletized and then melted, and additional additives may be added to the molten thermoplastic vulcanizate product. This latter process may also be referred to as a "second pass" addition of ingredients.

[0092]

[0095] Despite the fact that the elastomer may be partially or fully cured, thermoplastic vulcanizates can 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 a co-continuous morphology or phase transition may also be present. In embodiments in which the cured rubber is in the form of finely divided, well-dispersed particles in a 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%, e.g., at least 60%, e.g., at least 75% of the rubber particles may have an average diameter of less than 5 μm, e.g., less than 2 μm, e.g., less than 1 μm.

[0093]

[0096] The degree of cure can be measured by determining the amount of rubber extractable from the thermoplastic vulcanizate using cyclohexane or boiling xylene as an extractant. Preferably, the rubber has a degree of cure such that 15 weight percent or less, e.g., 10 weight percent or less, e.g., 5 weight percent or less, e.g., 3 weight percent or less, is extractable with cyclohexane at 23°C, as described in U.S. Patent Nos. 4,311,628, 5,100,947, and 5,157,081, all of which are incorporated herein by reference. Alternatively, the rubber may have a crosslink density of at least 4 x 10 per milliliter of rubber. -5 , e.g., at least 7 × 10 -5 , e.g., at least 10 × 10 -5 The degree of cure may be molar. See Ellul et al., Crosslink Densities and Phase Morphologies in Dynamically Vulcanized TPEs, Rubber Chemistry and Technology, Vol. 68, pp. 573-584 (1995).

[0094]

[0097] The resulting thermoplastic vulcanizate may have a desirable density that allows it to be utilized in molded parts as described herein. In this regard, the density may be less than 0.3 g / cm. 3 or may be higher, for example 0.4 g / cm 3 or may be higher, for example 0.5 g / cm 3 or may be higher, for example 0.6 g / cm 3 or may be higher, for example 0.65 g / cm 3 or may be higher, for example 0.7 g / cm 3 or may be higher, for example 0.75 g / cm 3 or may be higher, for example 0.8 g / cm 3 or may be higher, for example 0.85 g / cm 3 or may be higher, for example 0.9 g / cm 3 or may be higher, for example 0.95 g / cm 3 or may be higher, for example 1 g / cm 3 or may be higher, for example 1.05 g / cm 3 or may be higher, for example 1.1 g / cm 3 or may be higher, for example 1.15 g / cm 3 or may be higher, for example 1.2 g / cm 3 or higher. The density is 2 g / cm 3 or less 、 For example, 1.8g / cm 3 or less, e.g., 1.6 g / cm 3 or less, e.g., 1.4 g / cm 3 or less 、 For example, 1.3 g / cm 3 or less, e.g., 1.2 g / cm 3 or less, e.g., 1.1 g / cm 3 or less, e.g., 1.0 g / cm 3 or less, e.g., 0.95 g / cm 3or less, e.g., 0.90 g / cm 3 or less, e.g., 0.7 g / cm 3 or less, e.g., 0.6 g / cm 3 or less, e.g., 0.55 g / cm 3 Or it may be less than that.

[0095] G. Gasket formation

[0098] Once the thermoplastic vulcanizate is formed, it can be molded into a molded part, particularly the gasket described herein for use in an electrolytic cell, using any of a variety of techniques known in the art. For example, the thermoplastic vulcanizate can be advantageously fabricated by employing typical molding processes, such as injection molding, extrusion molding, compression molding, blow molding, rotational molding, overmolding, and the like. Generally, these processes involve heating the thermoplastic vulcanizate to a temperature equal to or exceeding the melting point of the thermoplastic resin to form a preform that fits into a mold cavity, forming a molded part, cooling the molded part to a temperature at or below the crystallization temperature of the thermoplastic vulcanizate, and removing the molded part from the mold. The mold cavity defines the shape of the molded part, such as a gasket. The molded part is cooled in the mold at a temperature at or below the crystallization temperature of the thermoplastic vulcanizate, after which the molded part can be removed from the mold. This process may also utilize extrusion molding to form a gasket. In this regard, the thermoplastic vulcanizate may be extruded as described herein. Once the thermoplastic vulcanizate exits the extruder, it may be formed or shaped to form a gasket. Such gaskets may be formed by using a specific die to shape the thermoplastic vulcanizate as it exits the extruder. Such a shaping / forming process, e.g., an extrusion process, may be automated or may be a robotic process.

[0096] II. electrolytic cell

[0099] As indicated above, gaskets formed from thermoplastic vulcanizates as disclosed herein can be used in electrolytic cells. Generally, the electrolytic cell may not necessarily be limited. For example, the electrolytic cell may be an alkaline electrolytic cell, such as an anion exchange electrolytic cell. In this regard, such electrolytic cells can be used to produce hydrogen gas and oxygen gas from a liquid, where the gases can be provided in a separated state. Generally, the liquid may be pure water or a solution. For example, the solution may be an electrolyte solution containing an electrolyte, such as sodium hydroxide or potassium hydroxide, to produce hydrogen gas and oxygen gas. To produce the gas, the electrolytic cell utilizes an electrolytic cell. Although there may be some structural differences, the electrolytic cell generally includes a gasket, a diaphragm / separator, and electrodes, such as a cathode and an anode, at both ends thereof.

[0097]

[0100] Generally, components, such as electrodes, may be contained within a spacer frame. Specifically, such a spacer frame may surround the components to maintain a desired orientation. As an example, the spacer frame may surround an electrode, such as a cathode. Similarly, the spacer frame may surround a second electrode, such as an anode. In addition, in some embodiments, the spacer frame may surround a diaphragm, such as an ion-permeable diaphragm. Nevertheless, a first spacer frame may be separated from a second spacer frame by a gasket comprising a thermoplastic vulcanizate as defined herein. In this regard, a first surface of the gasket may be in contact with the first spacer frame, while a second, opposing surface of the gasket may be in contact with the second spacer frame. Furthermore, in one embodiment, such contact may be adjacent at the edges of the respective spacer frames.

[0098]

[0101] Although the above describes the use of a spacer frame to surround and retain the diaphragm, in one embodiment, the diaphragm may be contained within a gasket. For example, the gasket may include a slit portion at the inner periphery, particularly along the entire inner periphery. The slit may be provided to retain the ion-permeable diaphragm. Furthermore, such a slit need not extend across the entire width of the gasket, such that the outer edge of the diaphragm is contained within the gasket.

[0099]

[0102] As just one possible arrangement, the electrolytic cell may include a first spacer frame containing a first electrode, e.g., a positive electrode, followed by a gasket. The gasket may be followed by a second spacer frame holding a diaphragm. Such a spacer frame may be followed by a third spacer frame containing a gasket and a second electrode, e.g., a negative electrode. When the diaphragm is held within a gasket, the electrolytic cell may include a first spacer frame containing a first electrode, e.g., a positive electrode, followed by a gasket. The gasket may be followed by a second spacer frame containing a second electrode, e.g., a negative electrode.

[0100]

[0103] By placing a diaphragm behind each electrode constituting the cell, oxygen gas and hydrogen gas generated from each electrode surface can be discharged to the outside in a separate state, achieving high purity. Ion-permeable diaphragms generally have low gas permeability, low conductivity, and high strength. The diaphragm may have a pore size on the micrometer scale, for example, about 0.1 micrometer to about 100 micrometers, or in some embodiments, about 1 micrometer to about 50 micrometers. Typical diaphragms include microporous ceramics and microporous polymer films (e.g., porous polyvinyl chloride (PVC), polyolefins, and PTFE). The diaphragm may include an anion-exchange membrane to allow the movement of anions through the membrane while preventing convection and diffusion. One example of such a membrane is a polymer electrolyte membrane, which allows the passage of anions (e.g., hydroxide anions) generated on one side of a bipolar electrode to the associated side of an adjacent bipolar electrode. Such anion exchange membranes can include, for example, a zirconia and polysulfone composite available under the trade name Zirfon®. Combinations of macroporous separators, microporous separators, and / or anion exchange materials can also be employed in the membrane.

[0101]

[0104] In addition, the shape of the gasket is not necessarily limited. For example, the gasket may be circular, rectangular, oval, or the like. In either case, the shape of the gasket may correspond to the outer periphery of the electrode. Specifically, the diameter or cross-section of the gasket may be the same as that of the electrode / spacer frame. Furthermore, the thickness may not be limited. For example, the thickness may be 0.1 mm or more, for example, 0.2 mm or more, for example, 0.3 mm or more, for example, 0.5 mm or more, 25 mm or less, for example, 4 mm or less, for example, 3 mm or less, for example, 2.5 mm or less, for example, 2 mm or less, for example, 1.5 mm or less, for example, 1 mm or less, for example, 0.8 mm or less, for example, 0.6 mm or less, for example, 0.5 mm or less, or for example, 0.4 mm or less.

[0102]

[0105] As described herein, a liquid may be provided to generate a gas, such as hydrogen gas or oxygen gas. In this regard, the gasket may include first and second passage holes at one side or end (or upper or lower portion) of the gasket and / or electrode for the passage of a first gas and a second gas, respectively. In addition, the gasket may include third and fourth passage holes at the opposing end or side (or other of the lower or upper portion) of the gasket and / or electrode for the passage of a liquid / electrolyte. Specifically, the gasket may include a passage hole communicable with an anolyte inlet, a passage hole communicable with a catholyte inlet, a passage hole communicable with an anolyte / gas outlet, and a passage hole communicable with a catholyte / gas outlet. Generally, these inlet passage holes may be formed on one side or end of the gasket and / or electrode, while the outlet passage holes may be formed on the opposing end or side of the gasket and / or electrode. Although two passage holes for the liquid / electrolyte are described above, it is understood that in some embodiments, there may be only one passage hole for the liquid / electrolyte.

[0103]

[0106] On the other hand, when a voltage is applied to the anode and cathode electrodes, for example, when the anode electrode is charged with the opposite polarity compared to the cathode, the electrolyte solution present between the electrodes is electrolyzed to produce oxygen gas and hydrogen gas. The diaphragm can prevent the oxygen gas produced from the anode (+) charged surface of one electrode from mixing with the hydrogen gas produced from the cathode (-) charged surface of the opposing electrode.

[0104]

[0107] While the above may generally refer to a cell including two electrodes, it is understood that the electrolytic cell may also include a cell stack. For example, a cell stack may be formed by a plurality of cells including electrodes with spacer frames and gaskets for sealing purposes. The respective cells may be in fluid and electrical communication with each other. Additionally, the individual cells may be attached to each other, for example, by gluing, welding, bolting, etc., or by the use of a case or shell that holds the individual components of the stack together with a pressure seal.

[0105]

[0108] FIG. 1 illustrates one embodiment of an electrolytic cell for use in an electrolytic cell. Such a cell may include spacer frames 208, 210, and 212. Spacer frames 210 and 212 contain electrodes, while spacer frame 208 contains a diaphragm. Included between the spacer frames is a gasket 102 formed of a thermoplastic vulcanizate described herein. Spacer frames 208, 210, and 212 may define sealing channels in their surfaces that can retain the gasket for sealing to prevent leakage from the assembled cell. While spacer frames 208, 210, and 212 are illustrated using a generally circular shape, it will be understood that they may have any suitable shape (e.g., square, oval, rectangular, etc.).

[0106]

[0109] Generally, a first spacer frame 210 can hold the bipolar electrodes. The electrolyzer cell may include a second spacer frame 208, which can hold the diaphragm. A third spacer frame 212 can also hold the bipolar electrodes. Within such frames, they may include passage holes that align with passage holes in other spacer frames within the cell, or in the case of more than one cell, within the cell stack. Such alignment can aid in the movement of liquid / electrolyte and gases produced by electrolysis.

[0107]

[0110] In addition to the above, additional electrolytic cell spacer frames and gaskets comprising thermoplastic vulcanizates as described may be incorporated into the cell. For example, in some embodiments, the electrolytic cell may include gas diffusion layers, which are typically disposed between the bipolar plates and the electrodes. The gas diffusion layers may be held by the electrolytic cell spacer frames described herein. Gaskets, as defined herein, may be utilized to separate such spacer frames from adjacent spacer frames. Of course, the electrolytic cell may include gaskets made from materials other than the thermoplastic vulcanizates of the present disclosure, if desired.

[0108]

[0111] Furthermore, electrolyzers can be utilized within electrolyzer systems. For example, referring to FIG. 2, an embodiment of an electrolyzer system is illustrated containing an electrolyzer stack 35 incorporating multiple bipolar electrodes in electrolyzer cells 10 as described above. Of course, any electrolyzer cell or stack thereof may include a spacer frame and gaskets, and the gaskets may comprise thermoplastic vulcanizates, and such cells or stacks thereof may be incorporated into an electrolyzer system. In the illustrated embodiment, feed may be supplied to both sides of the electrolyzer cell stack 35 via a cathode inlet 30 to the cathode side of the cells and via an anode inlet 32 ​​to the anode side of the cells. In some embodiments, feed may be fed to only one side of the cells in the stack 35. In embodiments in which the cells include exchange membrane separators, feed may be fed to both sides of the cells to maintain membrane hydration. Product outlets 31, 33 can discharge electrolysis products (e.g., oxygen and hydrogen) from the cell stack 35. The feed may be an alkaline aqueous solution, such as, but not limited to, an aqueous solution of a suitable alkaline substance, such as potassium hydroxide, sodium hydroxide, lithium hydroxide, or mixtures thereof. For example, the feed may contain about 20 wt.% to about 40 wt.% of the alkaline substance in aqueous solution.

[0109]

[0112] Feeds can be provided to inlets 30, 32 via a common feed line 121 plus a recycle hose 122. In an embodiment, the feed to the cells can be pretreated, such as by an initial feed 120 to a heat exchanger 108 to heat the feed to a suitable temperature (e.g., about 80°C). Outlets 31, 33 can carry the oxygen and hydrogen products to additional system elements, such as product separators 112, 114, a demister 128, and a dryer 129. The separated hydrogen and oxygen products of cell stack 35 can be discharged from systems 125, 130. For example, the hydrogen product can be discharged directly to the system for utilization, e.g., to a fuel cell as a fuel, to a storage facility, or to a secondary system for further processing, e.g., chemical formation.

[0110]

[0113] To operate the alkaline electrolyzer cell stack 35, the water pump 134 is operated to introduce the feed 120 to any pre-treatment procedures, such as heating via the heat exchanger 108, and then to one or both sides of the electrochemical cell stack via the inlets 32, 33. In some embodiments, the feed may be fed to both sides of the cell stack 35 to provide the cell elements (e.g., anion exchange membranes) with a moisture content high enough to enable performance of the cell stack 35.

[0111]

[0114] At the cathode of the electrolytic cell (or the cathode side of a bipolar electrode), water reacts according to the following half-reactions: 2H2O+2e￣→H2+2OH￣ The hydroxide ions thus formed at the cathode are transported to the anode, where they react according to the following half-reaction: 2OH￣→1 / 2O2+H2O+2e￣

[0115] The oxygen and hydrogen are then released from the cell stack 35 via outlets 31, 33. Generally, the products can be released along with the feed, as long as the feed is provided in a quantity sufficient to purge the products from the cell stack 35. The oxygen and hydrogen products can then be separated from the remaining feed, for example, via product separators 112, 114, demister 128, and dryer 129, to provide purified hydrogen product 130 and oxygen product 125. The separated feed can be recycled to the cell stack 35 via recycle hose 122.

[0112]

[0116] The following test methods may be employed to determine the properties described herein. Test Method Melting Point, Glass Transition Temperature, and Heat of Fusion: Melting point ("Tm"), glass transition temperature ("Tg"), and heat of fusion ("Hf") can be measured by differential scanning calorimetry ("DSC") as known in the art using commercially available instruments such as the TA Instruments Model Q100. Typically, a 6-10 mg 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. From this heating cycle (the "first heat"), the glass transition temperature is measured. For samples exhibiting multiple peaks, the melting point (or melting temperature) is defined as the melting temperature of the peak associated with the largest endothermic calorimetric response in that temperature range from the DSC melting trace. The T gThe glass transition temperature reported is the midpoint of the step change when heated during the second heating cycle. The area under the DSC curve is used to determine the heat of transition (heat of fusion, Hf, when melting, or heat of crystallization, Hc, when crystallizing; if the Hf value from melting differs from the Hc value obtained at the heat of crystallization, the value from melting (Tm) should be used), which can be used to calculate the degree of crystallinity (also called percent crystallinity). The percent crystallinity (X%) is calculated using the formula: [area under the curve (in J / g) / H° (in J / g)] x 100, where H° is the heat of fusion of the homopolymer of the major monomer component. These values ​​for H° can be taken from the Polymer Handbook, 4th Edition, published by John Wiley and Sons, New York, 1999, where a value of 290 J / g is used as the equilibrium heat of fusion (H°) for 100% crystalline polyethylene, a value of 140 J / g is used as the equilibrium heat of fusion (H°) for 100% crystalline polybutene, and a value of 207 J / g (H°) is used as the heat of fusion for 100% crystalline polypropylene.

[0113]

[0057] These and other modifications and variations of the present disclosure can be practiced by those skilled in the art without departing from the spirit and scope of the present disclosure. In addition, it is to be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those skilled in the art will understand that the foregoing description is by way of example only and is not intended to limit the invention as further described in the appended claims.

Claims

1. An electrolytic cell including a first spacer frame, a second spacer frame, and a first gasket having a first surface in contact with the first spacer frame and a second, opposing surface in contact with the second spacer frame. An electrolytic cell comprising: the first gasket comprises a thermoplastic vulcanizate including a thermoplastic resin and an at least partially cured elastomer; The electrolytic bath described above, wherein the thermoplastic vulcanizate exhibits a Shore A hardness (ISO 868-85) of 35 to 100.

2. 2. The electrolytic cell of claim 1, wherein the thermoplastic vulcanizate exhibits a Shore A hardness (ISO 868-85) of 40 to 70.

3. 3. An electrolytic cell according to claim 1 or 2, wherein the thermoplastic vulcanizate exhibits a 100% modulus of at least 1 MPa.

4. 4. An electrolytic cell according to any one of claims 1 to 3, wherein the thermoplastic vulcanizate exhibits a coefficient of friction of 3 or less.

5. 5. An electrolytic cell according to any one of claims 1 to 4, wherein the thermoplastic vulcanizate exhibits a tensile stress at break of from 0.5 MPa to 20 MPa.

6. 6. An electrolytic cell according to any one of claims 1 to 5, wherein the thermoplastic vulcanizate exhibits an elongation at break of 200% or more and 1000% or less.

7. 7. The electrolytic cell according to any one of claims 1 to 6, wherein the thermoplastic resin comprises polyimide, polyester, polyamide, poly(phenylene ether), polycarbonate, styrene-acrylonitrile copolymer, polyethylene terephthalate, polybutylene terephthalate, polystyrene or derivatives thereof, polyphenylene oxide, polyoxymethylene, fluorine-containing thermoplastic resins, or mixtures thereof.

8. 7. The electrolytic cell according to any one of claims 1 to 6, wherein the thermoplastic resin comprises a polyolefin.

9. 9. The electrolytic cell of claim 8, wherein the polyolefin comprises polypropylene.

10. 10. The electrolytic cell according to any one of claims 1 to 9, 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.

11. Electrolytic cell according to any one of claims 1 to 9, wherein the elastomer comprises a polyolefin elastomeric copolymer.

12. Electrolytic cell according to any one of claims 1 to 9, wherein the elastomer comprises ethylene / propylene / non-conjugated diene copolymer rubber (EPDM).

13. Electrolytic cell according to any one of claims 1 to 9, wherein the elastomer comprises an ethylene acrylic copolymer.

14. Electrolytic cell according to any one of claims 1 to 9, wherein the elastomer comprises butyl rubber.

15. 15. The electrolytic cell of any one of claims 1 to 14, wherein the thermoplastic vulcanizate comprises from about 10 wt. % to about 90 wt. % of the elastomer and from about 10 wt. % to about 90 wt. % of the thermoplastic resin, the wt. % being based on the weight of the thermoplastic vulcanizate.

16. Electrolytic cell according to any one of claims 1 to 15, wherein the thermoplastic vulcanizate further comprises a colorant or pigment.

17. 17. The electrolytic cell according to any one of claims 1 to 16, wherein the gasket defines a first passage hole and a second passage hole for the passage of a first gas and a second gas, respectively, and a third passage hole for the passage of a liquid.

18. 17. An electrolytic cell according to any one of claims 1 to 16, wherein the first spacer frame surrounds a first electrode and the second spacer frame surrounds a diaphragm.

19. 18. The electrolytic cell of claim 17, further comprising a third spacer frame and a gasket comprising a second thermoplastic vulcanizate, the gasket having a first surface in contact with the second spacer frame and a second, opposing surface in contact with the third spacer frame.

20. 20. The electrolytic cell of claim 19, wherein the third spacer frame surrounds the second electrode.

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