Fluoroelastomer Compounds

Abstract

The present invention relates to fluoroelastomer compounds containing a particular type of carbon black, which when added to fluoroelastomer compounds, improves both tensile strength and elongation at break.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention relates to fluoroelastomer compounds containing certain types of carbon black and curatives, and to articles cured from the compounds. [Background technology]

[0002] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 384,684, filed November 22, 2022, the disclosure of which is expressly incorporated herein by reference in its entirety.

[0003] Elastomer compounds, including fluoroelastomers, have enjoyed significant commercial success due to their ability to be used in harsh environments, particularly during exposure to high temperatures and highly reactive chemicals. For example, these compounds are used in seals for hot sections of aircraft engines, in oil well rigs, and as sealing elements in industrial equipment operating at high temperatures.

[0004] The properties of cured elastomeric compounds result primarily from the stability and inertness of the copolymerized monomers that make up the majority of the polymeric backbone of these compounds. Such monomers include tetrafluoroethylene and perfluoro(alkyl vinyl) ethers. To fully develop their elastomeric properties, elastomeric compounds are typically crosslinked, i.e., vulcanized or cured. For this purpose, a small percentage of cure site monomers are copolymerized with the monomers (fluorinated or perfluorinated). By crosslinking, the cure site monomers react with the curing agent to form a crosslinked elastomeric body in the form of an article.

[0005] Cure site monomers containing at least one nitrile group, such as perfluoro-8-cyano-5-methyl-3,6-dioxa-1-octene, may also be used, and compositions containing such cure site monomers are described in U.S. Pat. No. 7,999,049, columns 10-16.

[0006] Fluoroelastomer compounds containing amidines are described in US Pat. No. 10,472,494, which is incorporated herein by reference in its entirety.

[0007] The mechanical properties of cured elastomer compounds are usually adjusted by incorporating various additives. Tensile strength and elongation at break are both highly desired for cured elastomer compounds, but it is difficult to obtain both high tensile strength and high elongation at break. Summary of the Invention [Means for solving the problem]

[0008] Certain types of carbon black improve both tensile strength and elongation at break when added to fluoroelastomer compounds.

[0009] The present invention provides (A) Below; (1) one or more unsaturated fluorinated olefins; (2) one or more unsaturated fluorinated olefin comonomers different from (1) and selected from the group consisting of fluorovinyl ethers, unsaturated fluorinated olefins, unsaturated olefins, and mixtures thereof; (3) one or more cure site monomers selected from the group consisting of nitrile-containing fluorinated olefins and nitrile-containing fluorinated vinyl ethers; and a fluoroelastomer comprising copolymerized units of: (B) at least one curing agent; (C) one or more carbon blacks, wherein at least one of the carbon blacks has a molecular weight of 20 to 40 m 2 / g of statistical thickness specific surface area and The present invention relates to a compound comprising:

[0010] The present invention further comprises, prior to curing: (A) Below; (1) one or more fluorinated olefins; (2) one or more unsaturated fluorinated olefin comonomers different from (1) and selected from the group consisting of fluorovinyl ethers, unsaturated fluorinated olefins, unsaturated olefins, and mixtures thereof; (3) one or more cure site monomers selected from the group consisting of nitrile-containing fluorinated olefins and nitrile-containing fluorinated vinyl ethers; and a fluoroelastomer comprising copolymerized units of: (B) at least one curing agent; (C) one or more carbon blacks, wherein at least one of the carbon blacks has a molecular weight of 20 to 40 m 2 / g of statistical thickness specific surface area and The present invention relates to an article comprising a cured product of a compound comprising the compound. DETAILED DESCRIPTION OF THE INVENTION

[0011] Abbreviation; The claims and the description herein should be interpreted using the abbreviations and definitions set forth below. "h" and "hrs" refer to hours. "%" refers to the term percent. "Mol %" refers to mole percent. "wt%" refers to weight percent. "°C" refers to degrees Celsius. "Parts" refers to parts by weight. "phr" refers to parts per hundred parts of fluoroelastomer (rubber); those skilled in the art use and recognize this measurement term. For example, 3 parts of a component per 100 parts of fluoroelastomer would be written as 3 phr. In these compounds, processes, and articles described herein, phr is based on 100 parts fluoroelastomer. "g" stands for gram. "Ph" refers to a phenyl ring.

[0012] definition As used herein, the article "a" refers to one as well as more than one and does not necessarily restrict its referent noun to the grammatical category of singular.

[0013] As used herein, the terms "about" and "exactly or approximately," when used to modify an amount or value, refer to an approximation of an amount or value that is greater than or less than the exact amount or value recited in a claim or the present specification. The exact value of an approximation is determined by what a person skilled in the art would recognize as an appropriate approximation to the exact value. As used herein, terms conveying similar values ​​that are not exactly recited in a claim or the present specification can produce results or effects equivalent to those recited in the claim or the present specification, and therefore, a person skilled in the art would recognize that they are acceptable results of similar values.

[0014] As used herein, the term "article" refers to an unfinished or finished item, thing, object, or element or feature of an unfinished or finished item, thing, or object. As used herein, if the article is unfinished, the term "article" can refer to any item, thing, object, element, device, etc. having a form, shape, configuration that can undergo further processing to become a finished product. When the article is unfinished, the term "preform" can refer to the form, shape, configuration of which any portion can undergo further processing to become a finished product. As used herein, if the article is finished, the term "article" refers to the article, thing, object, element, device, etc. in a form, shape, configuration that is suitable for a particular use / purpose without further processing in whole or in part.

[0015] An article may include one or more elements or subassemblies that are either partially completed and awaiting further processing, or are in assembly with other elements / subassemblies that together would comprise a completed article. Additionally, as used herein, the term "article" may refer to a system or configuration of articles.

[0016] As used herein, the terms "include," "including," "includes," "including," "having," "having," or any other variation thereof, refer to a non-exclusive inclusion. For example, a process, method, article, or apparatus that includes a list of elements is not limited to only the listed elements and may include other elements not expressly listed or inherent. Furthermore, unless expressly stated to the contrary, "or" refers to an inclusive or, not an exclusive, inclusive or. For example, condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or absent), A is false (or absent) and B is true (or present), and A and B are both true (or present). As used herein, the terms "include," "including," "including," "having," "consisting essentially of," and "consisting of," or any other variation thereof, may refer to either a non-exclusive or an exclusive inclusion.

[0017] When these terms refer to a more exclusive inclusion, they limit the scope of the claim to those recited materials or steps that materially affect the novel element of the invention being described.

[0018] When these terms refer to an entirely exclusive inclusion, they exclude any element, step, or ingredient not expressly recited in the claim. As used herein, terms describing molecules or polymers follow the terminology in the IUPAC Compendium of Chemical Terminology version 2.15 (International Union of Pure and Applied Chemistry), dated September 7, 2009.

[0019] As used herein, the term "unsaturated fluorinated olefin" refers to a linear, branched, or cyclic hydrocarbon structure containing at least one unsaturated double bond and at least one fluorine atom.

[0020] As used herein, the term "alkyl" refers to linear, branched, or cyclic hydrocarbon structures and combinations thereof. Alkyl does not include aromatic structures. Examples of linear alkyl groups include methyl, ethyl, propyl, butyl, pentyl, and hexyl groups. Examples of branched alkyl groups include, for example, s-butyl and t-butyl, and isopropyl groups. Examples of cyclic hydrocarbon groups include cyclopropyl, cyclopentyl, cyclohexyl, cyclobutyl, and cyclooctyl groups.

[0021] As used herein, the term "alkoxy" or "alkoxyl" refers to an alkyl group connected to an oxygen atom by a single bond. The other bond to the oxygen atom is connected to a carbon atom. Examples include methoxy, ethoxy, propoxy, isopropoxy, cyclopropyloxy, and cyclohexyloxy.

[0022] As used herein, the term "compound" refers to a composition that is curable, i.e., a curable composition and a mixture of chemicals that includes at least a fluoroelastomer and a curing agent, which mixture of chemicals has not been cured or subjected to processing conditions that would cause the mixture of chemicals to undergo curing.

[0023] As used herein, the prefix term "fluoro," when placed as a prefix before a chemical name, refers to a chemical having at least one fluorine atom, as exemplified by the following names: fluoroelastomer, perfluoroelastomer, fluorovinyl, and perfluorovinyl ether. The prefix "fluoro," when placed as a prefix before a chemical name, specifically includes "perfluoro" chemicals. Thus, the prefix "fluoro," when preceding a chemical name, denotes both "fluoro" and "perfluoro" forms.

[0024] As used herein, the term "cured" refers to a resultant material that includes a fluoroelastomer and that has been exposed to those conditions (i.e., cure conditions) that cause the fluoroelastomer molecules to form sufficient crosslinks between them so that the resultant material assumes a form, shape, configuration, or structure that cannot be reprocessed, molded, or extruded into something different. That is, once the resultant material that includes a fluoroelastomer has been cured by exposure to cure conditions, the material cannot be recured to assume a substantially different form, shape, configuration, or structure.

[0025] As used herein, the terms "curing" and "cured" refer to the processing of a compound (also referred to herein as a curable composition) that results in a material that assumes a form or shape or configuration or structure that cannot be reprocessed, molded, or extruded into something different. Such processing is referred to as a "curing process / treatment" that requires exposure of the compound to specific conditions (such conditions are referred to as curing conditions) to initiate the curing process.

[0026] The material resulting from the curing process is a "cured" material, i.e., an article as defined herein above. For clarity, curing results in the compound taking on the form, shape, configuration, or structure of an article. Cured articles of the compounds described herein include, but are not limited to, O-rings, seals, and gaskets.

[0027] The terms "curing" and "cured" also expressly include varying degrees of processing of a compound such that the resulting material assumes a form or shape or configuration or structure that cannot be reprocessed, molded, or extruded into something different and may exhibit particular physical properties as a result of curing.

[0028] In essence, these compounds may be initially cured to reach a non-reprocessable form, shape, etc., which is referred to herein as "curing." The cured compound may then be subjected to additional curing conditions, which provide additional subsequent cure. Such additional curing conditions may be variously referred to herein as either "curing" or "post-curing." That is, the terms "curing" and "cured" refer to the initial curing process that results in an initially cured, resulting material, and also specifically refer to any subsequent curing process that results in a subsequently cured, resulting material that may or may not have different material or physical properties than that of the initially cured, resulting material.

[0029] (Scope and Preferred Variants) Any range described herein expressly includes its endpoints unless otherwise specified. The description of an amount, concentration, or other value or parameter as a range specifically discloses all possible ranges formed from any possible range upper limit and any possible range lower limit, regardless of whether such range upper and lower limit pairs are expressly disclosed herein. The compounds, processes, and articles described herein are not limited to the specific values ​​disclosed in defining ranges in this description.

[0030] The disclosure herein of any variations on the materials, chemicals, methods, steps, values ​​and / or ranges, etc. of the processes, compounds and articles described herein is specifically intended to include—whether identified as preferred or non-preferred—any possible combination of materials, methods, steps, values, ranges, etc. For purposes of providing accurate and sufficient support for the claims, any disclosed combination is a preferred variation of the processes, compounds and articles described herein.

[0031] (Compound) A) Fluoroelastomer The fluoroelastomers described herein may be fluorinated or perfluorinated and comprise at least three copolymerized monomer units: (1) one or more unsaturated fluorinated olefins; (2) one or more unsaturated fluorinated olefin comonomers different from the unsaturated fluorinated olefin (1) and selected from the group consisting of fluorovinyl ethers, unsaturated fluorinated olefins, unsaturated olefins, and mixtures thereof; and (3) one or more cure site monomers selected from the group consisting of nitrile-containing fluorinated olefins, nitrile-containing fluorinated vinyl ethers, or mixtures thereof, wherein the mole percent of each of (1), (2), and (3) is based on the total mole percent of (1), (2), and (3) in the fluoroelastomer.

[0032] Alternatively, the fluoroelastomer may be fluorinated or perfluorinated and may comprise at least three copolymerized monomer units: (1) about 25 to 74.9 mole % of one or more unsaturated fluorinated olefins; (2) about 25 to 74.9 mole % of one or more unsaturated fluorinated olefin comonomers different from the unsaturated fluorinated olefin (1) and selected from the group consisting of fluorovinyl ethers, unsaturated fluorinated olefins, unsaturated olefins, and mixtures of at least two of fluorovinyl ethers, unsaturated fluorinated olefins, and unsaturated olefins; and (3) about 0.1 to 10 mole % of one or more cure site monomers selected from the group consisting of nitrile-containing fluorinated olefins, nitrile-containing fluorinated vinyl ethers, or mixtures thereof, where the mole % of each of (1), (2), and (3) is based on the total mole percentage of (1), (2), and (3) in the fluoroelastomer.

[0033] The fluoroelastomers described herein may contain any of a variety of end groups resulting from the use of various initiators or chain transfer agents during polymerization, including, but not limited to, sulfonate, sulfonic acid, carboxylate, carboxylic acid, carboxamide, difluoromethyl, trifluorovinyl, or perfluorinated alkyl groups.

[0034] (1) Unsaturated fluorinated olefin The unsaturated fluorinated olefin (1) may be an unsaturated monomer containing at least one fluorine atom, or at least two fluorine atoms, or alternatively, a perfluorinated monomer. Examples of unsaturated fluorinated olefins include tetrafluoroethylene (CF), hexafluoropropylene, 1,1-difluoroethylene, 1,1,2-trifluoroethylene, 1-fluoroethylene, and combinations thereof. The concentration of the unsaturated fluorinated olefin (1) may be in the range of 25 to 74.9 mole percent of the total moles of monomer units in the fluoroelastomer.

[0035] (2) Unsaturated fluorinated olefin comonomer The unsaturated fluorinated olefin comonomer (2), which is different from the unsaturated fluorinated olefin (1), is selected from the group consisting of fluorovinyl ethers, unsaturated fluorinated olefins, unsaturated olefins, and mixtures thereof.

[0036] Examples of fluorovinyl ethers used to prepare fluoroelastomers include perfluoro(alkyl vinyl) ethers (PAVE), perfluoro(alkoxy vinyl) ethers, fluoro(alkyl vinyl) ethers, fluoro(alkoxy vinyl) ethers, and mixtures thereof. Suitable perfluorinated (alkyl vinyl) ethers that can be used to prepare the compounds described herein include those represented by formulas (II)-(VI): CF2=CFO(R f’ O) n (R f” O) m R f (II) (In the formula, R f’ and R f” are different linear or branched perfluoroalkylene groups of 2 to 6 carbon atoms, m and n are independently 0 to 10, and R f is a perfluoroalkyl group of 1 to 6 carbon atoms).

[0037] Additional examples of perfluoro(alkyl vinyl) ethers include compositions of formula (III): CF2=CFO(CF2CFXO) n R f (III) (wherein X is F or CF3, n is 0 to 5, and R f is a perfluoroalkyl group of 1 to 6 carbon atoms. Alternatively, n is 0 or 1 and R f contains 1 to 3 carbon atoms. Examples of such perfluorinated (alkyl vinyl) ethers include perfluoro(methyl vinyl) ether and perfluoro(propyl vinyl) ether.

[0038] Other perfluoro(alkyl vinyl) ether monomers for the preparation of fluoroelastomers include monomers of formulae (IV), (V), and (VI): CF2=CFO[(CF2) m CF2CFZO] n R f (IV) (In the formula, R f is a perfluoroalkyl group having 1 to 6 carbon atoms, m=0 or 1, n=0 to 5, and Z=F or CF3); CF2=CFO[(CF2CFCF3O) n (CF2CF2CF2O) m (CF2) p ]C x F 2x+1 (V) (wherein m and n=1 to 10, p=0 to 3, and x=1 to 5). Specific embodiments of this category include monomers where n=0 to 1, m=0 to 1, and x=1; CF2=CFOCF2CF(CF3)O(CF2O) m C n F 2n+1 (VI) (wherein n=1 to 5, m=1 to 3, or n=1) Examples include:

[0039] Examples of perfluoro(alkyl vinyl) ethers include perfluoromethyl vinyl ether, perfluoropropyl vinyl ether, and perfluoroethyl vinyl ether. Examples of perfluoro(alkoxy vinyl) ethers include perfluoromethoxy vinyl ether, perfluoropropoxy vinyl ether, and perfluoroethoxy vinyl ether.

[0040] Examples of unsaturated fluorinated olefins include tetrafluoroethylene (CF); hexafluoropropylene; 1,1-difluoroethylene; 1,1,2-trifluoroethylene; 1-fluoroethylene; 1-fluoropropylene; 1,1-difluoropropylene; 1,1,3-trifluoropropylene; 1,1,3,3,3-pentafluoropropylene; and combinations thereof. Examples of unsaturated olefins include ethylene, propylene, 1-butene, 2-butene, and combinations thereof. Mixtures of fluorovinyl ethers, unsaturated fluorinated olefins, and unsaturated olefins may also be used.

[0041] The concentration of unsaturated fluorinated olefin comonomer in the fluoroelastomer ranges from 25 to 74.9 mole percent, alternatively from 30 to 65 mole percent, alternatively from 45 to 55 mole percent, based on the total mole percent of monomer units in the fluoroelastomer.

[0042] (3) Cure site monomer The fluoroelastomer (A) further comprises copolymerized units of one or more cure site monomers containing at least one nitrile substituent. Alternatively, the cure site monomer is selected from the group consisting of nitrile-containing fluorinated olefins and nitrile-containing fluorinated vinyl ethers (3). The amount of such cure site monomers is typically 0.1 to 10 mole percent, alternatively 0.3 to 1.5 mole percent, based on the total mole percent of polymerizable monomer units used to prepare the fluoroelastomer. While multiple cure site monomers may be present, the cure site monomer contains at least one nitrile substituent. Useful nitrile-containing cure site monomers include monomers of formulae (VII)-(XI): CF2=CF-O(CF2) n -CN (VII) (wherein n=2 to 12, or 2 to 6); CF2=CF-O[CF2-CFCF3-O] n -CF2-CFCF3-CN (VIII) (wherein n=0 to 4, or 0 to 2); CF2=CF-[OCF2CFCF3] x -O-(CF2) n -CN (IX) (wherein x=1 to 2 and n=1 to 4); and CF2=CF-O-(CF2) n -O-CF(CF3)CN (X) (wherein n=2 to 4).

[0043] A monomer of formula (IX) is used as the cure site monomer. In particular, the cure site monomer includes a perfluorinated polyether having a nitrile group and a trifluorovinyl ether group. Alternatively, the cure site monomer is perfluoro(8-cyano-5-methyl-3,6-dioxa-1-octene) (8-CNVE) and a monomer of formula (XI): CF2=CFOCF2CF(CF3)OCF2CF2CN (XI) It is expressed as:

[0044] B) Hardener The compound contains at least one curing agent (B). Any curing agent can be used provided that it is capable of reacting with the cure site described above.

[0045] A suitable curing agent (B) is a compound that decomposes at a temperature of 40°C to 330°C, or 90°C to 220°C, to generate ammonia. This is also called an ammonia-generating compound. Examples of such ammonia-generating compounds include dicyandiamide, aldehyde-ammonia condensation products including acetaldehyde-ammonia, and other compounds such as hexamethylenetetramine; carbamates such as t-butyl carbamate, benzyl carbamate, and HCFCFCH(CH)OCONH; urea; urea hydrochloride; thiourea; amides such as phthalamide; metal ammine complexes such as tetraamine copper(II) sulfate hydrate; ammonia-Lewis acid adducts; carboxamides such as oxamic acid; biuret; and unsubstituted amidines such as formamidine, formamidine hydrochloride, and formamidine acetate.

[0046] Other suitable curing agents (B) are compounds that form nitrogen-containing heterocyclic bridges. Examples of such compounds include triazines, benzimidazoles, benzoxazoles, triazoles, amidines, and hydrazides.

[0047] Other examples of the type of curing agent (B) that can be used in the compounds described herein include organotin curing agents or amino-group-containing benzene curing agents. Non-limiting examples of organotin curing agents include, but are not limited to, allyl-, propargyl-triphenyl-, and allenyltin curing agents. Specific examples of organotin curing agents include tetraalkyltin, tetraaryltin, and tetraphenyltin curing agents.

[0048] Examples of amino group-containing benzene curing agents include the bis(aminophenols) and bis(aminothiophenols) of formula (XII) and (XIII) and the tetraamines of formula (XIV).

[0049] [ka]

[0050] [ka]

[0051] (wherein A is SO2, O, CO, alkyl of 1 to 6 carbon atoms, perfluoroalkyl of 1 to 10 carbon atoms, or a carbon-carbon bond connecting two aromatic rings)

[0052] The amino and hydroxyl groups in the above formulas XII and XIII are interchangeable at the meta and para positions relative to group A. Specific examples of bis(aminophenol) and bis(aminothiophenol) curing agents include 2,2-bis[3-amino-4-hydroxyphenyl]hexafluoropropane (diaminobisphenol AF); 4,4'-sulfonylbis(2-aminophenol); 3,3'-diaminobenzidine; and 3,3',4,4'-tetraaminobenzophenone, with 3',3'-diaminobenzidine being preferred.

[0053] The amount of curative used will necessarily vary depending on the degree of crosslinking desired in the final product and the type and concentration of reactive moieties in the compounds described herein. An example of the amount of curative is about 0.1 to 7 parts of compound per 100 parts of perfluoroelastomer, preferably about 1 to 5 parts of compound per 100 parts of perfluoroelastomer.

[0054] C) Carbon Black: The compound of the present invention contains one or more carbon blacks (C). The carbon black of the present invention has a statistical thickness specific surface area (STSA) of 20 to 40 m as measured by ASTM D6556-07. 2 / g. STSA is the external surface area accessible to rubber, and the total surface area (NSA measurement) is the total surface area including micropores. The STSA of the carbon black used in the compounds of this invention is alternatively 25-35 m 2 / g.

[0055] In addition to the STSA, the iodine adsorption number is greater than 60 g / kg, ideally greater than 145 g / kg. The iodine adsorption number can be measured according to ASTM D1510.

[0056] Furthermore, the carbon black of the present invention has a viscosity of 50 cm 3 / DBP absorption exceeding 100g or 74cm 3 The nitrogen adsorption specific surface area can be measured in accordance with ASTM D2414B.

[0057] Additionally, the pH of the carbon black is greater than 7, or even greater than 9.

[0058] The pH can be measured according to ASTM D1512.

[0059] This type of carbon black has undetectable PAHs (polycyclic aromatic hydrocarbons), with a detection limit of 5 ppb.The carbon black of the present invention may be amorphous.

[0060] The present inventors have discovered that the use of such particular carbon blacks in fluoroelastomer compounds increases tensile strength without decreasing elongation at break.

[0061] An example of a carbon black having the properties disclosed above is Carbon Neat 90, available from Carbon Neat.

[0062] The concentration of carbon black (C) in the compound ranges from 1 to 100 phr, or from 5 to 100 phr.

[0063] Two or more carbon blacks can be used, and when two or more carbon blacks are used, at least one of the carbon blacks must be a carbon black described above.

[0064] Other ingredients The compound described herein may additionally contain a non-perfluoro-containing elastomer that can crosslink independently with any of the fluoroelastomer (A) cure sites. Examples of non-perfluoro-containing elastomers include those having at least one crosslinkable group at the main chain or at least one end of a side chain that can crosslink with the fluoroelastomer (A), the group being selected from the group consisting of cyano (-CN), carboxyl (-COOH), alkoxycarbonyl (-COOR9, where R9 is a monovalent organic group), and acid halide group (-COX1, where X1 is a halogen atom).

[0065] Examples of perfluoro-free elastomers include, but are not limited to, fluorine-containing perfluoro-free rubbers; thermoplastic fluorine-containing rubbers; and rubber compositions containing fluorine-containing rubbers.

[0066] The fluorine-containing rubber may comprise monomer units independently selected from the group consisting of vinylidene fluoride (VDF), tetrafluoroethylene, and hexafluoropropylene, and at least one additional monomer such as tetrafluoroethylene, hexafluoropropylene, perfluoro(alkyl vinyl ether), chlorotrifluoroethylene, trifluoroethylene, trifluoropropylene, pentafluoropropylene, trifluorobutene, tetrafluoroisobutene, vinyl fluoride, and iodine-containing fluorinated vinyl ether, ethylene, propylene, alkyl vinyl ether, and combinations thereof.

[0067] Additives typically utilized in compounding, such as stabilizers, plasticizers, lubricants, fillers, and processing aids, can be incorporated into the compounds described herein, provided they are sufficiently stable under the intended conditions of use. In particular, the incorporation of perfluoropolyethers can enhance low temperature performance.

[0068] In addition to or in combination with carbon black, non-carbon black fillers may be present in the compounds described herein. Examples of non-carbon black fillers that may be used include anhydrous silicas, such as acidic silica or fumed silica. Such silicas are available from Degussa Aktiengesellschaft (Frankfurt, Germany) under the Aerosil® trademark. A particularly useful type is Aerosil® 200 silica. Other suitable silicas include Reolosil® silicas, such as Reolosil® QS13, Reolosil® QS102, and Reolosil® QS30, available from Tokuyama Corporation (Tokyo). The amount of silica ranges from 1 to 25 phr, or alternatively, from 1 to 7 phr or less.

[0069] Additional types of fillers include fine powders or fluoroadditives. Fine powders are usually partially crystalline polymers. Fine powders include finely divided, easily dispersed plastic fluoropolymers that are solid at the highest temperatures used in the manufacture and curing of the compounds described herein. The term "solid" refers to plastic fluoropolymers that have a crystalline melting temperature higher than the processing temperature of the compounds described herein.

[0070] Fine powders that can be used in these compounds include, but are not limited to, those primarily from the group of polymers known as tetrafluoroethylene (TFE) polymers. This group includes polytetrafluoroethylene (PTFE) and copolymers of TFE with a low concentration of at least one copolymerizable modifying monomer, about 1 mole percent or less, so that the fine powder does not melt or soften during processing of the fluoroelastomer A containing the fine powder. The modifying monomer can be, for example, hexafluoropropylene (HFP), perfluoro(propyl vinyl) ether (PPVE), perfluorobutylethylene, chlorotrifluoroethylene, or another monomer that introduces a side group into the polymer molecule.

[0071] The tetrafluoroethylene polymers used as additives in these compounds include copolymers of TFE having a sufficient concentration of copolymerized units of one or more monomers to lower the melting point below that of PTFE. Such copolymers typically have a concentration of 0.5 to 60 x 10 3 They have melt viscosities in the Pa·s range, although viscosities outside this range are known. Perfluoroolefins and perfluoro(alkyl vinyl) ethers are preferred comonomers. Hexafluoropropylene and perfluoro(propyl vinyl) ether are most preferred. Examples of TFE copolymers include TFE / hexafluoropropylene copolymers and TFE / perfluoro(propyl vinyl) ether copolymers, provided that the melt temperature constraints relative to the processing temperature of the perfluoroelastomer are met. These copolymers may be utilized in powder form as isolated from the polymerization medium, provided the particle size is acceptable, or they may be milled to the appropriate particle size from larger size starting materials.

[0072] The amount of non-carbon black filler in these compounds is about 0.01 to 33 phr, or at least about 1 to 5 phr.

[0073] Compound preparation process and cured article The compounds described herein can be prepared by mixing the fluoroelastomer (A), curative (B), carbon black (C), and optional ingredients until homogeneous using rubber compounding procedures such as a two-roll rubber mill, an internal mixer such as a Banbury internal mixer, or an extruder. These compounds can be cured by applying sufficient heat and / or pressure to cause the curative (B) to crosslink with the cure site monomer, or a dual cure system can be used. When cured using compression molding, a press cure cycle is followed by a post-cure cycle during which the press-cured compound is heated to an elevated temperature above 300°C for several hours.

[0074] Upon curing, the compounds described herein become the articles described herein and exhibit thermal stability and chemical resistance suitable for the applications in which they are used. In particular, articles cured from the compounds exhibit both high tensile strength combined with high elongation at break. These articles are useful as: seals and gaskets for high temperature situations in a variety of chemical environments, in seals for high temperature automotive applications, and as O-rings. [Example]

[0075] material The fluoroelastomer (FE) contains: 48.8% by weight of tetrafluoroethylene (TFE) units, 49.0% by weight of perfluoro(methyl vinyl) ether (PMVE) units, and 2.2% by weight of perfluoro(8-cyano-5-methyl-3,6-dioxa-1-octene) (8-CNVE) units. The fluoroelastomer can be prepared by the process disclosed in U.S. Pat. No. 5,789,489, columns 10-11. Perfluoro(methyl vinyl) ether: available from Chemours. 8-CNVE: Perfluoro(8-cyano-5-methyl-3,6-dioxa-1-octene) can be prepared by the process disclosed in US Pat. No. 5,637,748. Hardener (CA-1): Dicyandiamide available from Sigma Aldrich. Carbon Black 1 (CB-1): Thermax® N908, a medium thermal carbon black, STSA 6-9, available from Cancarb Limited, Alberta, Canada. Carbon Black 2 (CB-2): Neat 90, available from CarbonNeat 16930 West Catawba Ave., Suite 102, Cornelius, NC 28031, STSA: 28-30.

[0076] Example 1 (E1), Example 2 (E2), and Comparative Example 1 (CE1) were prepared by compounding the raw materials on a two-roll rubber mill using the ingredients shown in Table 1. The ground compounds were formed into sheets, and the samples were die-cut into O-ring (AS214) or dogbone shapes to form test specimens. Elongation at break and tensile strength were measured according to ASTM D1414.

[0077] [Table 1]

Claims

1. A compound, (A) (1) one or more unsaturated fluorinated olefins; (2) one or more unsaturated fluorinated olefin comonomers different from (1) and selected from the group consisting of fluorovinyl ethers, unsaturated fluorinated olefins, unsaturated olefins, and mixtures thereof; (3) one or more cure site monomers selected from the group consisting of nitrile-containing fluorinated olefins and nitrile-containing fluorinated vinyl ethers; and a fluoroelastomer comprising copolymerized units of (B) at least one curing agent; (C) one or more carbon blacks, wherein at least one carbon black has a viscosity of 20 to 40 m ２ / g of statistical thickness specific surface area; Compound containing.

2. 10. The compound of claim 1, wherein the curing agent comprises a compound that decomposes at a temperature of from 40°C to 330°C to produce ammonia.

3. 10. The compound of claim 1, wherein the curative comprises a compound that produces a nitrogen-containing heterocyclic bridge.

4. 4. The compound according to claim 1, wherein the carbon black has an iodine adsorption number of at least 60 g / kg.

5. The compound according to any one of claims 1 to 4, wherein the carbon black comprises two or more types of carbon black.

6. The compound of any one of claims 1 to 5, wherein the unsaturated fluorinated olefin is selected from the group consisting of tetrafluoroethylene, hexafluoropropylene, and mixtures thereof.

7. 7. The compound of any one of claims 1 to 6, wherein the unsaturated fluorinated olefin comonomer is selected from the group consisting of perfluoro(methyl vinyl) ether, hexafluoropropylene, perfluoro(propyl vinyl) ether, and mixtures thereof.

8. 8. The compound of any one of claims 1 to 7, wherein the curing agent is selected from the group consisting of amidinoamidine HCl, N',N"-diaminoaminoamidine; phenyloxoaminoamidine, 3-(5-phenyl-4H-1,2,4-triazolyl)amidine, 1H-pyrrolylamidine, benzimidazole amidine, aminothioxoamidine; gianylthiourea, dicyandiamide, aminocarbonylmethylamidine HCl, N-aminoamidine bicarbonate, N"-1H-pyrazolyl-N'-t-butoxycarbonylamidine, 2-pyridylamidine HCl, sulfinoamidine, and mixtures thereof.

9. The compound according to any one of claims 1 to 8, further comprising at least one filler selected from the group consisting of non-perfluorinated fluorine-containing elastomers, fine powders, stabilizers, plasticizers, lubricants, processing aids, and mixtures thereof.

10. Before hardening, (A) (1) one or more fluorinated olefins; (2) one or more unsaturated fluorinated olefin comonomers different from (1) and selected from the group consisting of fluorovinyl ethers, unsaturated fluorinated olefins, unsaturated olefins, and mixtures thereof; (3) one or more cure site monomers selected from the group consisting of nitrile-containing fluorinated olefins and nitrile-containing fluorinated vinyl ethers; and a fluoroelastomer comprising copolymerized units of (B) at least one curing agent; (C) one or more carbon blacks, wherein at least one carbon black has a viscosity of 20 to 40 m ２ / g of a statistical thickness-specific surface area; An article comprising a cured product of a compound comprising:

11. 11. The article of claim 10 in the form of a gasket, a tube, a seal, and an O-ring.

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