Perfluoroelastomer Compound

Abstract

The present invention relates to perfluoroelastomer compounds containing specific types of carbon black, and cured articles formed from the compounds, which exhibit good processability during their manufacturing process, as well as many useful properties for the cured perfluoroelastomer articles.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 384,695, filed November 22, 2022, the disclosure of which is hereby expressly incorporated by reference in its entirety.

[0002] The present invention relates to perfluoroelastomer compounds containing particular types of carbon black and to cured articles formed from the compounds. [Background technology]

[0003] Fluoroelastomer articles have enjoyed outstanding commercial success because they can be used in harsh environments, especially during exposure to high temperatures and aggressive chemicals. For example, these articles are used in seals in hot sections or other sections of aircraft engines, in oil well drilling devices, and as sealing elements in industrial equipment operating at high temperatures.

[0004] The properties of perfluoroelastomer articles arise 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 the 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 monomer units. During crosslinking, the cure site monomers react with a curing agent to form a crosslinked elastomeric body in the form of an article.

[0005] Mechanical properties such as low compression set are also required for perfluoroelastomer articles for use in various industries. The mechanical properties of cured elastomer compounds are usually adjusted by incorporating additives. Carbon black is used as an additive to improve mechanical properties. U.S. Pat. No. 10,472,494, the entire contents of which are incorporated herein by reference, discloses a fluoroelastomer compound containing a specific type of curing agent and carbon black having an average particle size of at least about 100 nm to about 500 nm. Summary of the Invention [Problem to be solved by the invention]

[0006] During the curing of perfluoroelastomer compositions, the torque of the composition increases as the crosslinking increases. Because of the increased torque, the composition becomes very difficult to process. Therefore, there is a need for improving the processability during the curing process. [Means for solving the problem]

[0007] Perfluoroelastomer compounds containing certain types of carbon black exhibit good processability during the manufacturing process as well as many useful properties for the cured perfluoroelastomer articles.

[0008] The present invention relates to copolymerized monomer units of at least two types: (1) one or more perfluorinated olefins; and (2) perfluoro(alkyl vinyl) ethers, perfluoro(alkoxy vinyl) ethers, and perfluorovinyl ethers selected from the group consisting of mixtures of perfluoro(alkyl vinyl) ethers and perfluoro(alkoxy vinyl) ethers; and (3) at least one cure site selected from compositions containing a group or atom selected from a bromine atom, an iodine atom, and a nitrile group; a perfluoroelastomer comprising (B) one or more curing agents; (C) one or more carbon blacks, at least one of which has a viscosity of 20 to 40 m 2 and carbon black having an STSA of 1 / g.

[0009] The present invention further relates to articles manufactured using the compounds disclosed above. [Brief explanation of the drawings]

[0010] [Figure 1] 1A and 1B are moving die rheometer (MDR) curves showing cure kinetics, specifically for Ts2 and T90, for compounds containing specific carbon blacks or conventional carbon blacks, respectively. [Figure 2] 1A and 1B are MDR curves showing cure speed, specifically for Ts2 and T90, for compounds containing half the amount of coagent with a particular carbon black or conventional carbon black, respectively. 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 perfluoroelastomer (rubber); those skilled in the art use and recognize this term of measurement. For example, 3 parts of a component per 100 parts of fluoroelastomer would be written as 3 phr. In the compounds, processes, and articles described herein, phr is based on 100 parts of perfluoroelastomer. "g" stands for gram. "Ph" refers to a phenyl ring.

[0012] definition As used herein, the article "a" refers to one as well as to 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 described herein. The exact value of an approximation is determined by what a person of ordinary skill in the art would recognize as an appropriate approximation to the exact value. As used herein, the term conveys that a similar value not exactly recited in a claim or described herein can produce results or effects that are equivalent to those recited in the claim or described herein, which a person of ordinary skill in the art would recognize as being produced to an acceptable degree by a similar value.

[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, when an article is unfinished, the term "article" can refer to any item, thing, object, element, device, etc. that has a form, shape, or configuration that can undergo further processing to become a finished product. When an article is unfinished, the term "preform" can refer to the form, shape, or configuration of which any portion can undergo further processing to become a finished product. As used herein, when an article is finished, the term "article" refers to an item, thing, object, element, device, etc. that is in a form, shape, or configuration that is suitable for a particular use / purpose without further processing of the whole entity or any portion thereof. An article can 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 finished product. Additionally, as used herein, the term "article" can refer to a system or configuration of articles.

[0015] As used herein, the terms "comprise," "including," "includes," "including," "including," "have," "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 "comprise," "including," "include," "including," "having," "consisting essentially of," and "consisting of," or any other variation thereof, may refer to either a non-exclusive or an exclusive inclusion.

[0016] 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 recited novel element of the invention.

[0017] 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.

[0018] As used herein, the prefix term "perfluoro," when placed as a prefix before a chemical name, refers to a chemical that has every hydrogen atom replaced by a fluorine atom.

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

[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- 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 attached to an oxygen atom by a single bond. The oxygen atom's other bond is to a carbon atom. Examples include methoxy, ethoxy, propoxy, isopropoxy, cyclopropyloxy, and cyclohexyloxy.

[0022] As used herein, the term "another curing agent different from curing agent B" refers to a curing agent that does not have the same chemical structure as curing agent B.

[0023] 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 perfluoroelastomer 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.

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

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

[0026] The entity resulting from the curing process is a "cured" entity, i.e., an article as defined herein above. For clarity, curing results in the compound taking on the form or shape or 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 "cure" and "cured" also expressly include varying degrees of treatment of the compound such that the resulting entity 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 hardening.

[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 be further subjected to additional curing conditions that provide additional, subsequent hardening. Such additional curing conditions may be variously referred to herein as either "curing" or "post-curing." That is, the terms "cure" and "cured" refer to the initial hardening process that results in an initially hardened, resulting entity, and also specifically refer to any subsequent hardening process that results in a subsequently hardened, resulting entity that may or may not have different material or physical properties than that of the initially hardened, resulting entity.

[0029] Scope and Preferred Variations Any range set forth 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 upper range limit and any possible lower range limit, whether or not such upper and lower range 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 expressly intended to include—whether identified as preferred or non-preferred—any possible combination of materials, methods, steps, values, ranges, etc. For purposes of providing precise and sufficient support for the claims, any disclosed combination is a preferred variation of the processes, compounds, and articles described herein.

[0031] compound A) Perfluoroelastomer The perfluoroelastomers described herein contain at least two copolymerized monomer units: (1) one or more perfluorinated olefins and (2) a perfluorovinyl ether monomer selected from the group consisting of perfluoro(alkyl vinyl) ethers, perfluoro(alkoxy vinyl) ethers, or mixtures of perfluoro(alkyl vinyl) ethers and perfluoro(alkoxy vinyl) ethers, and (3) at least one cure site selected from the group consisting of bromine atoms, iodine atoms, and nitrile groups.

[0032] Alternatively, the perfluoroelastomers described herein comprise at least the following two copolymerized monomer units: (1) from about 25 to about 74.9 mole percent of one or more perfluorinated olefins and (2) from about 10 to about 74.9 mole percent of perfluorovinyl ether monomers selected from the group consisting of perfluoro(alkyl vinyl) ethers, perfluoro(alkoxy vinyl) ethers, or mixtures of perfluoro(alkyl vinyl) ethers and perfluoro(alkoxy vinyl) ethers, and (3) from about 0.1 to 3 mole percent of cure sites selected from the group consisting of bromine atoms, iodine atoms, and nitrile groups, where the mole percent of each of (1), (2), and (3) is based on the total mole percent of (1), (2), and (3) in the perfluoroelastomer.

[0033] The perfluoroelastomers described herein may contain any of a variety of end groups as a result of the use of various initiators or chain transfer agents during polymerization. Non-limiting examples of end groups include sulfonate, sulfonic acid, carboxylate, carboxylic acid, carboxamide, difluoromethyl, trifluorovinyl, or perfluorinated alkyl groups.

[0034] (1) Copolymerized perfluorinated olefins The copolymerized perfluorinated olefin includes a perfluorinated olefin. Examples of the perfluorinated olefin include tetrafluoroethylene (C2F4), hexafluoropropylene, and a mixture of tetrafluoroethylene and hexafluoropropylene. The concentration of the perfluorinated olefin is 25 to 74.9 mol% of the total moles of monomer units in the perfluoroelastomer.

[0035] (2) Perfluorovinyl ether monomer Perfluorovinyl ether monomers include perfluoro(alkyl vinyl) ethers (PAVEs), perfluoro(alkoxy vinyl) ethers, and mixtures thereof.

[0036] Suitable perfluorovinyl ether monomers include those having any one of the following formulas (I), (II), (III), (IV) or (V) herein: CF2=CFO(R f’ O) n (R f’’ ) m R f (I) (In the formula, R f’ and R f” is a linear or branched perfluoroalkylene group 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) CF2=CFO(CF2CFXO) n Rf (II) (wherein X is F or CF3, n is 0 to 5, and R f is a perfluoroalkyl group of 1 to 6 carbon atoms) Preferably, n is 0 or 1, and R f contains 1 to 3 carbon atoms. Examples of such fluorovinyl ether monomers include perfluoro(methyl vinyl) ether and perfluoro(propyl vinyl) ether. CF2=CFO[(CF2) m CF2CFZO] n R f (III) (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 (IV) (wherein m and n=1 to 10, p=0 to 3, and x=1 to 5), and monomers where n=m=0 to 1, and x=1 are included. CF2=CFOCF2CF(CF3)O(CF2O) m C n F 2n+1 (V) (wherein n=1 to 5, m=1 to 3, and / or n=1)

[0037] Mixtures of perfluoro(alkyl vinyl) ethers and perfluoro(alkoxy vinyl) ethers may also be used.

[0038] The concentration of the perfluorovinyl ether monomer ranges from about 10 to 74.9 mole percent, or from 15 to 60 mole percent of the total mole percent of (1) copolymerized perfluorinated olefin, (2) perfluorovinyl ether monomer, and (3) cure site monomer in the perfluoroelastomer.

[0039] (3) Hardened area The perfluoroelastomer further comprises one or more cure sites. Suitable cure sites include nitrile-containing or fluorinated olefins containing one or more bromine atoms or one or more iodine atoms, or mixtures thereof. Such fluorinated olefins include those represented by formula (VI) or (VII): CR 2 R 2 =(CR 3 R 4 )n-CR 5 R 6 (VI) (wherein n=1 to 4; R 1 , R 2 , R 3 , R 4 , and R 5 =H or F, where R 1 ~R 5 At least one of the is F; R 6 is Br or I, preferably I; or CF2 = CF-O(CR 7 R 8 ) n -R 9 (VII) (wherein n=1 to 4; R 7 and R 8 =H or F, where R 7 or R 8 At least one of the is F; R 9 is Br or I, preferably I) The hardening site includes a hardening site having

[0040] Perfluoroelastomers containing cure sites can also be obtained by polymerization processes carried out using bromine or iodine compounds as chain transfer agents.

[0041] Typical examples of bromine or iodine compounds that may be used include compounds of formula (VIII): R 10 Ix Br y (VIII) (wherein x and y are each an integer of 0 to 2, satisfying 1≦x+y≦2; R 10 is a saturated or unsaturated fluorohydrocarbon or chlorofluorocarbon group having 1 to 16 carbon atoms, or a hydrocarbon group having 1 to 3 carbon atoms, optionally containing an oxygen atom. By using a bromine compound or an iodine compound, iodine or bromine can be introduced into the polymer and function as a crosslinking point.

[0042] Examples of bromine compounds or iodine compounds include i,3-diiodoperfluoropropane, 2-iodoperfluoropropane, 1,3-diiodo-2-chloroperfluoropropane, 1,4-diiodoperfluorobutane, i,5-diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane, i,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane, diiodomethane, 1,2-diiodoethane, i,3-diiodo-n-propane, CF2Br2, BrCF2CF2Br, CF3CFBrCF2 Examples of suitable iodoperfluoroethanes include Br, CFClBr, BrCFCFClBr, CFBrClCFClBr, BrCFCFCFBr, BrCFCFBrOCF, i-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, i-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 3-bromo-4-iodoperfluorobutene-1, 2-bromo-4-iodoperfluorobutene-1, and monoiodomonobromo-substituted products, diiodomonobromo-substituted products, and (2-iodoethyl)- and (2-bromoethyl)-substituted products of benzene. These compounds may be used alone or in combination. Among these, 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, and 2-iodoperfluoropropane are preferred from the viewpoints of polymerization reactivity, crosslinking reactivity, and availability.

[0043] Suitable cure sites also include nitrile-containing fluorinated olefins and nitrile-containing fluorinated vinyl ethers. Useful nitrile-containing cure site monomers include those represented by formulas (IX)-(XIII): CF2-CF-O(CF2) n -CN (IX) (wherein n=2 to 12, preferably 2 to 6); F2=CF-O[CF2-CFCF3-O] n -CFCF3-CN (X) (wherein n=0 to 4, preferably 0 to 2); CF2=CF-[OCF2CFCF3]) x -O-(CF2) n -CN (XI) (wherein x=1 to 2 and n=1 to 4); and CF2=CF-O-(CF2) n -O-CF(CF3)CN (XII) (wherein n=2 to 4) Examples of the compounds include:

[0044] Alternatively, the cure site is perfluoro(8-cyano-5-methyl-3,6-dioxa-1-octene) (8-CNVE) and has the formula (XIII): CF2=CFOCF2CF(CF3)OCF2CF2CN (XIII) It is expressed as:

[0045] Perfluoroelastomers may contain any of a variety of end groups as a result of the use of various initiators or chain transfer agents during polymerization. Non-limiting examples of end groups include sulfonate, sulfonic acid, carboxylate, carboxylic acid, carboxamide, difluoromethyl group, trifluorovinyl group, or perfluorinated alkyl group.

[0046] The cure sites in the compounds described herein range from about 0.1 to about 10 mole percent, alternatively from 0.3 to 7 mole percent, alternatively from 0.3 to 2 mole percent of the total moles of polymerizable monomer units in the perfluoroelastomer.

[0047] (B) Hardener The perfluoroelastomers used in the compounds of the present invention can undergo crosslinking reactions with any of the known curatives for perfluoroelastomers, including, but not limited to, combinations of polyhydroxy compounds, such as organic peroxides, with polyfunctional coagents (U.S. Pat. Nos. 4,214,060; 4,983,680), organotins (U.S. Pat. No. 5,789,489), bis(aminophenols) such as bisaminobisphenol AF (U.S. Pat. No. 6,211,319 B1), aromatic tetraamines such as 3,3'-diaminobenzidine, 2,2-bis[3-amino-4-(N-phenylamino)phenyl]hexafluoropropane, and ammonia-generating compounds such as urea and other compounds disclosed in U.S. Pat. No. 6,281,296 and WO 01 / 27194.

[0048] One curing agent that can be used is an organic peroxide / multifunctional coagent system. Useful organic peroxides are those that generate free radicals at the curing temperature. Dialkyl peroxides or bis(dialkyl peroxides) that decompose at temperatures above 50°C are particularly preferred. Ditertiary butyl peroxide, which has a tertiary carbon atom attached to the peroxy oxygen, is often preferred. Among the most useful peroxides of this type are 2,5-dimethyl-2,5-di(tertiary butylperoxy)hexyne-3 and 2,5-dimethyl-2,5-di(tertiary butylperoxy)-hexane. Other peroxides can be selected from compounds such as dicumyl peroxide, dibenzoyl peroxide, tertiary butyl perbenzoate, and di[1,3-dimethyl-3-(t-butylperoxy)butyl]carbonate. When present in the curable compositions of the present invention, 1 to 5 phr of peroxide is typically used.

[0049] The polyfunctional coagent used with the organic peroxide is a polyunsaturated compound capable of synergizing with the peroxide to provide a useful cure. These coagents can be added in amounts equal to 0.1 to 10 phr, preferably 2 to 5 phr. The coagent can be one or more of the following compounds: triallyl cyanurate; triallyl isocyanurate; polytriallyl isocyanurate; tri(methallyl)isocyanurate; tris(diallylamine)-s-triazine; triallyl phosphite; N,N-diallyl acrylamide; hexaallyl phosphoramide; N,N,N',N'-tetraalkyl tetraphthalamide; N,N,N',N'-tetraallyl malonamide; trivinyl isocyanurate; 2,4,6-trivinylmethyltrisiloxane; and tri(5-norbornene-2-methylene) cyanurate. Triallyl isocyanurate (TAIC) is particularly useful.

[0050] Other curing agents that may be used in the compounds of the present invention include bis(aminophenols) such as diaminobisphenol AF, tetraamines, organotins, and compounds that decompose to form ammonia at cure temperatures, such as urea. When present in the compounds of the present invention, typically 0.1 to 7 phr of any one of the latter curing agents is used.

[0051] (C) Carbon black The compound of the present invention contains one or more kinds of carbon black. The carbon black of the present invention has a viscosity of 20 to 40 mPa. 2 / g, or 25-35m 2 / g. STSA is the external surface area accessible to the rubber, while the total surface area (NSA measurement) is the total surface area including pores. STSA can be measured according to ASTM D6556-07.

[0052] In addition, the iodine adsorption is greater than 60 g / kg, ideally at least 145 g / kg. Iodide absorption can be measured according to ASTM D1510.

[0053] Additionally, the carbon black of the present invention preferably has a nitrogen surface area of ​​at least 50 cm 3 / 100g or at least 74cm 3 The carbon black has a DBP absorption of at least 100g. The nitrogen surface area can be measured according to ASTM D2414B. Furthermore, the pH of the carbon black is at least 7, alternatively at least 9. The pH can be measured according to ASTM D1512.

[0054] This type of carbon black has undetectable PAHs (polyaromatic hydrocarbons) with a detection limit of 5 ppb. The carbon black of the present invention can be amorphous.

[0055] When such specific carbon blacks are used, the composition exhibits better processability.

[0056] Ts2 (often referred to as scorch time) is used as a time index to indicate the onset of cure, while T90 is the time when nearly all crosslinks have formed. Such indices are explained in ASTM D5289.

[0057] FIG. 1 is a moving die rheometer (MDR) chart showing the Ts2 and T90 of two compounds. The straight line represents the compound containing conventional carbon black (Thermax N908), while the dotted curve represents the compound of the present invention containing specific carbon black (CarbonNeat 90). The Ts2 of the present invention (i.e., the dotted line) is shifted to the right compared to the Ts2 of the conventional one (i.e., the straight line), which means that the Ts2 is longer. A longer Ts2 is preferable for obtaining a sufficient processing window, while a shorter T90 is better for completing the curing process and inspecting the cured article. The compound of the present invention containing specific carbon black exhibits a longer Ts2 with a shorter T90, i.e., better processability for molding the composition.

[0058] Also, as illustrated in Figure 2, the inventors of the present invention have found that when using such particular carbon blacks, the amount of coagent can be reduced to achieve a level of crosslinking at least the same and equivalent or better than that defined by MH on the MDR. If some amount of coagent is included in the cured article, the coagent will bleed out of the article, resulting in lower yields or the inability to produce the article.

[0059] An example of a carbon black having the properties disclosed above is CarbonNeat 90 available from Cancarb Limited.

[0060] The concentration of carbon black (C) in the compound ranges from 1 to 100 phr, or from 5 to 60 phr.

[0061] More than one type of carbon black can be used, and if more than one type of carbon black is used, at least one of the carbon blacks must be a carbon black described above.

[0062] Other ingredients The compounds described herein may further comprise a metal sulfide, such as those disclosed in U.S. Patent Application Publication No. 2017 / 0022347A. Examples of such metal sulfides include calcium sulfide, magnesium sulfide, manganese sulfide, iron sulfide, and copper sulfide. The concentration of the metal sulfide is generally about 0.1 to 20 phr, preferably 1 to 20 phr, and more preferably 5 to 20 phr.

[0063] The compounds described herein may further comprise a non-perfluoro-containing elastomer that can crosslink independently with any of the perfluoroelastomer (A) cure sites. Examples of non-perfluoro-containing elastomers include those having at least one crosslinkable group, at least in the main chain or at the end of the side chain, 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), that can crosslink with the perfluoroelastomer (A).

[0064] Examples of non-perfluoro-containing elastomers include, but are not limited to, rubbers that contain fluorine but are not perfluoro-containing; thermoplastic fluorine-containing rubbers; and rubber compositions containing fluorine-containing rubbers.

[0065] The fluorine-containing rubber may contain 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.

[0066] 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 for the intended conditions of use. In particular, the incorporation of perfluoropolyethers can enhance low temperature performance.

[0067] 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 can 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, Japan). The amount of silica ranges from 1 to 25 phr, but is preferably 1 to 7 phr or less.

[0068] Additional types of fillers include fine powders or fluoroadditives. Fine powders are usually partially crystalline polymers. Fine powders include finely divided, easily dispersible 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 above the processing temperature of the compounds described herein.

[0069] Fine powders that can be used in these compounds include, but are not limited to, those based on the group of polymers known as tetrafluoroethylene (TFE) polymers. This group includes polytetrafluoroethylene (PTFE) and copolymers of TFE with a low concentration of about 1 mole percent or less of at least one copolymerizable modifying monomer, 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.

[0070] 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 generally 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 they meet the melt temperature constraints related to the perfluoroelastomer processing temperature. These copolymers can be utilized in powder form as isolated from the polymerization medium, if the particle size is acceptable, or they can be ground to a suitable particle size starting from a larger size stock.

[0071] The amount of non-carbon black filler in these compounds ranges from about 0.01 to 35 phr, alternatively from about 0.1 to 20 phr, alternatively from at least about 1 to 5 phr.

[0072] Process for preparing compounds and cured articles The compounds described herein can be prepared by mixing the perfluoroelastomer (A), curative (B), carbon black (C), and optional ingredients until homogeneous using rubber compounding procedures such as a two-roll rubber mill, internal mixer, or extruder. These compounds can be cured by applying sufficient heat and / or pressure to cause the curative B to form crosslinks with cure sites, or a dual cure system can also be used. When compression molding is used for curing, the press cure cycle is preferably followed by a post-cure cycle to achieve an optimal cure state, during which the press-cured compound is heated at an elevated temperature above 200°C for several hours.

[0073] When cured, the compounds described herein become the articles described herein and exhibit thermal stability and chemical resistance suitable for the applications they are used in. These articles are useful as seals and gaskets for high temperature situations and in a wide range of chemical environments, as seals for high temperature automotive applications, and as O-rings.

[0074] The compounds of the present invention are useful for the manufacture of gaskets, tubing, seals, and other molded parts. Such articles are generally produced by molding a compound formulated from a curable composition with various additives under pressure, curing the part, and then subjecting it to a post-cure cycle. The cured composition has excellent mechanical properties as well as excellent thermal stability and chemical resistance.

[0075] The compounds of the present invention exhibit a favorable T90 for shorter cure times resulting in shorter molding cycle times for the composition, as well as a favorable longer Ts2 for a sufficient processing window. In addition, the amount of coagent that bleeds out can be reduced, which contributes to higher yields and avoids defects in the resulting articles. [Example]

[0076] Curing properties Unless otherwise stated, cure properties were measured using a Montech D-RPA 3000 under the following conditions (ISO 6502): Moving die frequency: 1.66Hz Hertz vibration amplitude: ±0.5° [degrees] Temperature: 160℃ Sample weight: 6 to 10 g Duration: 45 minutes The following cure parameters were recorded: MH: Maximum torque level, in dN·m ML: Minimum torque level, in dN·m ts2: Minutes up to 2.26dNm above ML tc90: Maximum torque up to 90% of the physical characteristics

[0077] physical properties Compression set was performed in terms of pride pips according to ISO 815.

[0078] raw materials Perfluoroelastomer A: A perfluoroelastomer containing (PMVE) and (TFE) was prepared by the process disclosed in US Pat. No. 6,646,077, columns 9-10. Carbon Black A: Neat 90 (manufactured by CarbonNeat, 16930 West Catawba Ave., Suite 102, Cornelius, NC 28031) STSA: 28-30 Carbon black B: N908 Ultra Pure (Cancarb Limited) STSA: 6-9 Crosslinking coagent TAIC: (TAIC DLC®-A 72% manufactured by Harwick Standard Distribution Corporation, Akron, Ohio, USA) Luperox® 101 XL 45, available from Arkema, is a hardener package containing 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane and inorganic carriers (CaCO) and (SiO). Crosslinking coagent: DIAK 8 manufactured by TMAIC (Vanderbilt Chemicals, LLC)

[0079] Examples 1 to 6 The compounds disclosed in Table 1 were prepared.

[0080] [Table 1]

[0081] Curable compositions (Examples 1-6) containing the ingredients shown in Table 1 were prepared by compounding these ingredients in a conventional manner using an internal mixer and / or a two-roll rubber mill. Properties are also shown in Table 1.

[0082] The cure characteristics of these compositions and the physical properties of the cured specimens (T90 + 5 minutes of 160°C press cure, followed by 4 hours of post-cure in an air oven at 232°C) were measured according to the test methods. The results are shown in Table 1. The compositions of the present invention (Examples 1 and 3) exhibit a much longer Ts2, while T90 is usually, but not necessarily, equal or slightly increased. Example 3 also shows that half the amount of coagent (1.5) is sufficient to obtain the same level of properties (compression set).

[0083] Example 5 shows that using the new carbon black described above, it is possible to achieve a much lower compression set than when using the TMAIC coagent. Reference Example 6 would not be considered acceptable as a sealing element given its very high compression set.

Claims

1. (A) at least two copolymerized monomer units: (1) one or more perfluorinated olefins; and (2) perfluorovinyl ethers selected from the group consisting of perfluoro(alkyl vinyl) ethers, perfluoro(alkoxy vinyl) ethers, and mixtures of perfluoro(alkyl vinyl) ethers and perfluoro(alkoxy vinyl) ethers; and (3) At least one cure site selected from compositions containing a group or atom selected from a bromine atom, an iodine atom, and a nitrile group. a perfluoroelastomer comprising (B) one or more curing agents; and (C) one or more carbon blacks, at least one of which has a viscosity of 20 to 40 m / s. ２ / g of STSA; and Compound containing.

2. The compound according to any one of claims 1 to 4, wherein the curing agent (B) comprises an organic peroxide and a polyfunctional crosslinking coagent.

3. 10. The compound of claim 1, wherein the carbon black has an iodide absorption of at least 60 g / kg as measured according to ASTM D1510.

4. 3. The compound of claim 1, wherein the carbon black is amorphous.

5. The compound according to any one of claims 1 to 3, wherein the carbon black comprises two or more types of carbon black.

6. The compound of any one of claims 1 to 5, further comprising at least one component selected from the group consisting of non-perfluorinated fluorine-containing elastomers, fine powders, stabilizers, plasticizers, lubricants, processing aids, and mixtures thereof.

7. An article manufactured using the compound according to any one of claims 1 to 6.

8. 10. The article of claim 7 in the form of a molded article selected from a gasket, a tube, a seal, a diaphragm, a sheet, and an O-ring.

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