Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C257/00—Compounds containing carboxyl groups, the doubly-bound oxygen atom of a carboxyl group being replaced by a doubly-bound nitrogen atom, this nitrogen atom not being further bound to an oxygen atom, e.g. imino-ethers, amidines
  • C07C257/10—Compounds containing carboxyl groups, the doubly-bound oxygen atom of a carboxyl group being replaced by a doubly-bound nitrogen atom, this nitrogen atom not being further bound to an oxygen atom, e.g. imino-ethers, amidines with replacement of the other oxygen atom of the carboxyl group by nitrogen atoms, e.g. amidines
  • C07C257/14—Compounds containing carboxyl groups, the doubly-bound oxygen atom of a carboxyl group being replaced by a doubly-bound nitrogen atom, this nitrogen atom not being further bound to an oxygen atom, e.g. imino-ethers, amidines with replacement of the other oxygen atom of the carboxyl group by nitrogen atoms, e.g. amidines having carbon atoms of amidino groups bound to acyclic carbon atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C257/00—Compounds containing carboxyl groups, the doubly-bound oxygen atom of a carboxyl group being replaced by a doubly-bound nitrogen atom, this nitrogen atom not being further bound to an oxygen atom, e.g. imino-ethers, amidines
  • C07C257/10—Compounds containing carboxyl groups, the doubly-bound oxygen atom of a carboxyl group being replaced by a doubly-bound nitrogen atom, this nitrogen atom not being further bound to an oxygen atom, e.g. imino-ethers, amidines with replacement of the other oxygen atom of the carboxyl group by nitrogen atoms, e.g. amidines
  • C07C257/18—Compounds containing carboxyl groups, the doubly-bound oxygen atom of a carboxyl group being replaced by a doubly-bound nitrogen atom, this nitrogen atom not being further bound to an oxygen atom, e.g. imino-ethers, amidines with replacement of the other oxygen atom of the carboxyl group by nitrogen atoms, e.g. amidines having carbon atoms of amidino groups bound to carbon atoms of six-membered aromatic rings
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C259/00—Compounds containing carboxyl groups, an oxygen atom of a carboxyl group being replaced by a nitrogen atom, this nitrogen atom being further bound to an oxygen atom and not being part of nitro or nitroso groups
  • C07C259/12—Compounds containing carboxyl groups, an oxygen atom of a carboxyl group being replaced by a nitrogen atom, this nitrogen atom being further bound to an oxygen atom and not being part of nitro or nitroso groups with replacement of the other oxygen atom of the carboxyl group by nitrogen atoms, e.g. N-hydroxyamidines
  • C07C259/18—Compounds containing carboxyl groups, an oxygen atom of a carboxyl group being replaced by a nitrogen atom, this nitrogen atom being further bound to an oxygen atom and not being part of nitro or nitroso groups with replacement of the other oxygen atom of the carboxyl group by nitrogen atoms, e.g. N-hydroxyamidines having carbon atoms of hydroxamidine groups bound to carbon atoms of six-membered aromatic rings
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/30—Introducing nitrogen atoms or nitrogen-containing groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/29—Compounds containing one or more carbon-to-nitrogen double bonds

Definitions

• Fluoroelastomers and more particularly, perfluoroelastomers are materials known for their high levels of chemical resistance, plasma resistance, acceptable compression set resistance and satisfactory mechanical properties. Fluoroelastomers have thus found use as seals, gaskets and linings. When high temperature or aggressive or harsh environments, such as corrosive fluids, solvents, lubricants, and oxidizing or reducing conditions are implicated, perfluoroelastomers are the materials of choice. Fluoroelastomers are made by various routes using fluorinated monomers.
• Perfluoroelastomers are typically formed by using perfluorinated monomers, including a perfluorinated curesite monomer, polymerizing the monomers and curing (cross-linking) the composition using a curing agent which reacts with the incorporated curesite monomer to form a material which exhibits elastomeric properties.
• Suitable curesite monomers include, among others, those having cyano curesites. Examples of primary and secondary cyano-containing curesite monomers are known in the art. It is believed that in curesite monomers having cyano curesites, certain curing agents trimerize the cyano cure sites which join to form triazines.
• Known curing agents include organometallic compounds and the hydroxides thereof, especially organotin compounds, including allyl-, propargyl-, triphenyl- and allenyl tin and the hydroxides.
• organotin compounds including allyl-, propargyl-, triphenyl- and allenyl tin and the hydroxides.
• the tetraalkyltin compounds or tetraaryltin compounds, for example tetraphenyltin are common.
• these curing agents provide a relatively slow rate of cure, are toxic and can introduce metallic contaminants to resulting elastomers.
• Curing agents containing amino groups have also been employed.
• Bisaminophenols, bisaminothiophenols and bisamidrazones are additional types of curing agents.
• Those having a diphenyl structure having substitutions on each phenyl ring of amino and hydroxyl, diamine, and amino and thio are generally known in the art as being connected by structures including: —SO 2 —, —O—, —CO—, alkyl groups of 1-6 carbon atoms, and a carbon-carbon double bond. While perfluoroalkyl groups of 1-10 carbon atoms have been loosely described, actual synthesis and use of such compounds as curatives have not been demonstrated.
• diphenyl structure type materials which are in use and have known syntheses, are primarily compounds which have three carbon alkyl groups and in which the phenyl groups are attached to the central (second) carbon in the bis- position.
• curative of this type is 2,2-bis[3-amino-4-hydroxyphenyl] hexafluoropropane, also known as diaminobisphenol AF or BOAP.
• BOAP is a crystalline solid with a melting point of about 245-248° C. BOAP is not very compatible with perfluoroelastomers, is difficult to disperse rapidly and uniformly with perfluoroelastomers, and is thus a relatively slow-acting curative.
• the invention includes monoamidine-based and monoamidoxime-based curatives, co-curatives and cure accelerators for perfluoroelastomeric compositions.
• the invention further includes such materials as curatives having the general formula (I):
• Y is selected from the group consisting of substituted alkyl, alkoxy, aryl, aralkyl or aralkoxy groups of from 1 to about 22 carbon atoms; substituted or unsubstituted halogenated alkyl, alkoxy, aryl, aralkyl or aralkoxy groups of from about 1 to about 22 carbon atoms, and perfluoroalkyl, perfluoroalkoxy, perfluoroaryl, perfluoroaralkyl or perfluoroaralkoxy groups of from 1 to about 22 carbon atoms; and R 1 is hydrogen; substituted or unsubstituted lower alkyl or alkoxy groups of from 1 to about 6 carbon atoms; and an amino group; and R 2 is R 1 or hydroxyl.
• the invention also includes bisamidine-based curatives, co-curatives and cure accelerators for perfluoroelastomeric compositions.
• the invention further includes such compounds as represented by formula (II):
• D is selected from the group consisting of unsubstituted or substituted halogenated alkyl, alkoxy, aryl, aralkyl or aralkoxy groups having from about 1 to about 22 carbon atoms; and perfluoroalkyl, perfluoroalkoxy, perfluoroaryl, perfluoroaralkyl or perfluoroalkoxy groups of from 1 to about 22 carbon atoms; and R 1 and R 2 are each independently selected to be hydrogen; substituted or unsubstituted lower alkyl or alkoxy groups of from 1 to about 6 carbon atoms and an amino group.
• the invention includes a curable perfluoroelastomeric composition, comprising: (a) a perfluoropolymer having at least one curesite monomer comprising a cyano functional group; and (b) at least one monoamidine-based or monoamidoxime-based curative.
• a curable perfluoroelastomeric composition is also within the invention which comprises (a) a perfluoropolymer having at least one curesite monomer comprising a cyano functional group; (b) a functionalized diphenyl-based curative; and (c) a cure accelerator selected from the group consisting of at least one monoamidine-based cure accelerator, at least one monoamidoxime-based cure accelerator, at least one bisamidine-based cure accelerator and combinations thereof.
• Preferred curable perfluoroelastomeric compositions are also included in the invention in which the functionalized diphenyl-based curative has formula (III):
• R 3 and R 4 are each independently selected from the group consisting of a carbon atom; substituted and unsubstituted and branched and straight chain carbon groups of from about 2 to about 22 carbon atoms selected from the group consisting of alkyl groups, halogenated alkyl groups, and perfluorinated alkyl groups, each of which groups may be interrupted by at least one oxygen atom;
• each Z is independently selected from the group consisting of an amino, mercapto, sulfhydryl, or hydroxyl group;
• each J is independently selected to be formula (IV):
• each A is independently selected from the group consisting of formula (IV); a fluorine atom; and unsubstituted and substituted and branched and straight chain carbon-based groups which are selected from group consisting of alkyl, halogenated alkyl, and perfluoroalkyl groups of from 1 to about 22 carbon atoms; each of which groups may be interrupted by at least one oxygen atom; wherein when r is 0 and R 3 is a carbon atom, at least one of J and each A is not formula (IV).
• the invention further includes a curative for a perfluoroelastomeric composition, in which the curative has formula (III) as noted above.
• the invention includes a curative for a perfluoroelastomeric composition, comprising a functionalized diphenyl-based curative which has a sufficiently high molecular weight so that the melting point is no greater than about 240° C., and in certain preferred embodiments is no greater than about 230° C.
• Y is selected from the group consisting of substituted alkyl, alkoxy, aryl, aralkyl or aralkoxy groups of from 1 to about 22 carbon atoms; substituted or unsubstituted halogenated alkyl, alkoxy, aryl, aralkyl or aralkoxy groups of from about 1 to about 22 carbon atoms, and perfluoroalkyl, perfluoroalkoxy, perfluoroaryl, perfluoroaralkyl or perfluoroaralkoxy groups of from 1 to about 22 carbon atoms; and R 1 is hydrogen; substituted or unsubstituted lower alkyl or alkoxy groups of from 1 to about 6 carbon atoms; and an amino group; and R 2 is R 1 or hydroxyl, and wherein the compound is used as a curative for a perfluoroelastomeric composition.
• a method for curing a perfluoroelastomeric composition comprises using a mixture of (i) at least one compound selected from the group consisting of monoamidine-based compounds, monoamidoxime-based compounds, and mixtures thereof and (ii) at least one bisamidine-based compound as co-curatives for the perfluoroelastomeric composition.
• a method for accelerating curing of a perfluoroelastomeric composition comprises using a cure accelerator for a curative, wherein the cure accelerator is selected from the group consisting of a monoamidine-based compound, a monoamidoxime-based compound, a bisamidine-based compound and combinations thereof.
• the invention also includes a method for curing a perfluoroelastomeric composition comprising using a functionalized diphenyl-based curative having a sufficiently high molecular weight such that the melting point is no greater than about 240° C. as a curative for the perfluoroelastomeric composition, and in certain preferred embodiments is the melting point is no greater than about 230° C.
• a method for making a curative comprises (a) reacting an organic alkylacid with an alcohol to form an alkylester; (b) reacting the alkyl ester with ammonia to form an alkylcarboxyamide; (c) reacting the alkylcarboxyamide with a dehydrating agent to form an alkyl nitrile; and (d) reacting the alkyl nitrile with at least one of ammonia or an amine to form a curative, wherein the curative is capable of curing or accelerating the cure of a perfluoroelastomeric composition.
• the invention includes a method for making a bisaminophenol-based curative. That method comprises: (a) reacting an perfluoroacyl fluoride with potassium fluoride to form a potassium alcoholate reaction product; (b) reacting the potassium alcoholate reaction product with a perfluoroallylfluorosulfate to form a perfluoroallyl ether; (c) reacting the perfluoroallyl ether with an oxidizing agent to form a perfluoroglycidyl ether; (d) reacting the perfluoroglycidyl ether with aluminum chloride in a fluorinated solvent to isomerize an epoxide group on the perfluoroglyicdyl ether to a ketone; (e) reacting the ketone group with phenol in the presence of hydrogen fluoride to form a bisphenol-based compound; (f) nitration of the bisphenol-based compound to give a bisnitrophenol-based compound;
• a substituted bisaminophenyl-based curative for perfluoroelastomers having cyano-group containing curesite monomers is included within the invention.
• the bisaminophenyl-based curative is a substituted bisaminophenyl-based curative which has formula (IIIa):
• R 3 is a carbon atom; Z is an amino, sulfhydryl, or hydroxyl group; J is formula (IV):
• A is selected from the group consisting of unsubstituted and substituted and branched and straight chain carbon-based groups, wherein the carbon-based groups are selected from the group consisting of perfluoroalkyl and perfluoroalkoxy groups of from 1 to about 22 carbon atoms.
• the invention further includes a perfluoroelastomeric composition
• a perfluoroelastomeric composition comprising a bisaminophenyl-based curative for perfluoroelastomers having cyano-group containing curesite monomers, wherein the curative is a substituted bisaminophenyl-based curative which has formula (III):
• R 3 is a carbon atom; Z is an amino, sulfhydryl, or hydroxyl group; J is formula (IV):
• A is selected from the group consisting of unsubstituted and substituted and branched and straight chain carbon-based groups, wherein the carbon-based groups are selected from the group consisting of perfluoroalkyl and perfluoroalkoxy groups of from 1 to about 22 carbon atoms.
• the present invention is directed to low melting diphenyl-based, preferably diaminophenyl-based and more preferably perfluorinated diaminophenol-based curatives and co-curatives for perfluoroelastomeric compositions and novel methods of synthesis of preferred functionalized diphenyl-based curing agents.
• the invention is further directed to amidine-based cure accelerators, curatives and co-curatives for perfluoroelastomers.
• the curing agents and co-curing agents of the invention show improved mixing with perfluoroelastomeric compositions and the curatives, co-curatives and accelerators further demonstrate faster cure rates compared with conventional curing agents such as BOAP. Additionally, the amidine-based curatives and accelerators provide faster cures.
• a perfluoroelastomer may be any cured elastomeric material, derived by curing a perfluoroelastomeric composition (as defined herein) which includes a curable perfluoropolymer having a functional group to permit cure.
• a perfluoroelastomer is substantially completely fluorinated with respect to the carbon atoms of the perfluoropolymer. By this it is meant that as would be understood, based on this disclosure, that some residual hydrogen may exist in the functional crosslinking group in some perfluoroelastomeric compositions according to the present disclosure.
• the perfluoropolymers used in perfluoroelastomeric compositions to form perfluoroelastomers upon cure, are formed by polymerizing one or more perfluorinated monomers, one of which preferably has a perfluorinated curesite monomer having a functional group to permit curing.
• a perfluoroelastomeric composition is a polymeric composition including a curable perfluoropolymer.
• the perfluoropolymer as noted above is formed by polymerizing two or more perfluorinated monomers, plus at least one perfluorinated monomer which has at least one functional group to permit curing, i.e. at least one perfluoropolymeric curesite monomer.
• Such materials are also referred to general as FFKMs (perfluoroelastomers) in accordance with the American Society for Testing and Materials (ASTM) definition (ASTM-D-1418-01a), incorporated herein fully by reference and are also described further herein.
• a perfluoroelastomer is a perfluorinated rubber of the polymethylene type having all fluoro, perfluoroalkyl, or perfluoroalkoxy substitutent groups on the polymer chain; a small fraction of these groups may contain functionality to facilitate vulcanization.
• the perfluoroelastomer composition may include any suitable curable perfluoropolymer(s) (FFKM) capable of being cured to form a perfluoroelastomer, and one or more curing agents as described herein.
• Such perfluoroelastomeric compositions may preferably include two or more of various perfluorinated copolymers of at least one fluorine-containing ethylenically unsaturated monomer, such as tetrafluoroethylene (TFE); a perfluorinated olefin, such as hexafluoropropylene (HFP); and a perfluoroalkylvinyl ether (PAVE) which include alkyl groups that are straight or branched and which include one or more ether linkages, such as perfluoro(methyl vinyl ether), perfluoro (ethyl vinyl ether), perfluoro(propyl vinyl ether) and similar compounds.
• TFE tetrafluoroethylene
• HFP hexafluoropropylene
• PAVE perfluoroalkylvinyl ether
• PAVES examples include those described in U.S. Pat. No. 5,001,278 and in WO 00/08076, incorporated herein by reference.
• Other suitable PAVEs are described, for example, in U.S. Pat. Nos. 5,696,189 and 4,983,697, also incorporated herein by reference.
• Preferred perfluoropolymers are terpolymers or tetrapolymers of TFE, PAVE, and at least one perfluorinated cure site monomer which incorporates a functional group to permit crosslinking of the terpolymer, at least one of which is a curesite capable of being cured by the curatives and co-curatives of the invention.
• the curesite monomer(s) provide curesites which may be cured with either the inventive curative or inventive co-curatives or by other curatives not within the scope of the invention, but which are capable of having an accelerated cure when acted on by the cure accelerators of the present invention.
• Most preferred curesite monomers include those having cyano curesites, regardless of the location of the cyano group, e.g., primary and secondary cyano group curesite monomers. Examples of cyano curesite monomers are described in detail herein, and may be found in, for example, U.S. Pat. No. 4,281,092. Such cyano group containing cure site monomers are well known in the art. Combinations of one or more of these curesite monomers with each other or with other well known curesite monomers may also be used within the scope of the invention.
• Useful cyano cure site monomers include fluorinated olefins and fluorinated vinyl ethers, each having a cyano group of which the following are general examples:
• Specific examples include primary curesite monomers such as CF 2 ⁇ CFOCF 2 CF(CF 3 )OCF2CF2CN (referred to generally as 8-CNVE) and secondary curesite monomers such as CF 2 ⁇ CF—O[CF 2 ] 3 —O—CF[CF 3 ]—CN.
• Such curesite monomers may be used alone or in combination.
• a combination of curesite monomers as shown below in a fluoropolymeric or perfluoropolymeric chain as follows:
• p represents a secondary curesite monomer present in a fluoropolymer or perfluoropolymers in an amount from about 0.1 to about 12 mol %, preferably about 1 to about 4 mol %
• a represents a primary curesite monomer present in an amount from about 0.1 to about 12 mol % and preferably from about 1 to about 7 mol %. It is preferred that the molar ratio of the primary curesite monomer to the secondary curesite monomer in the copolymer is from about 1:1 to about 10:1, preferably 9:1.
• cure site monomers which contain cyano groups as curesites and those which do not contain cyano groups may be used in addition to or, in certain cases, in place of the preferred curesite monomers noted above, provided that the curesite monomers are capable of being cured by the preferred curatives and co-curatives and/or capable of experiencing an accelerated curing reaction when using the cure accelerators of the invention as described herein.
• curesite monomers include olefins, including partially or fully halogenated olefins, such as ethylene, vinylidene fluoride, vinyl fluoride, trifluoroethylene, bromotetrafluorobutene, bromotrifluoroethylene, 1-hydropentafluoropropene and 2-hydropentafluoropropene.
• olefins including partially or fully halogenated olefins, such as ethylene, vinylidene fluoride, vinyl fluoride, trifluoroethylene, bromotetrafluorobutene, bromotrifluoroethylene, 1-hydropentafluoropropene and 2-hydropentafluoropropene.
• additional cure site monomer(s) may be present in ranges as noted above and are preferably are generally present in amounts of about 0.1 to about 5 mole percent, more preferably about 0.1 to about 2.5 mole percent, and most preferably about 0.3 to about 1.5 mole percent.
• additives such as co-curatives, curing agents or accelerators, other than those of the present invention; processing aids; fillers and the like may also be included as optional components of the perfluoroelastomeric compositions of the invention.
• additives include fillers such as graphite, carbon black, clay, silicon dioxide, fluoropolymeric particulates (for example, TFE homopolymer and copolymer micropowders), barium sulfate, silica, titanium dioxide, acid acceptors, cure accelerators, glass fibers, or polyaramid fibers such as Kevlar, other curing agents and/or plasticizers or other additives known or to be developed in the fluoroelastomeric art and perfluoroelastomeric art.
• fillers such as graphite, carbon black, clay, silicon dioxide, fluoropolymeric particulates (for example, TFE homopolymer and copolymer micropowders), barium sulfate, silica, titanium dioxide, acid accept
• Preferred perfluoropolymers/perfluoroelastomers include Simriz®, available from Freudenberg of Germany, Dyneon®, available from Minnesota Mining & Manufacturing in Minnesota, Daiel-Perfluor®, available from Daikin Industries, Ltd. of Osaka, Japan. Similar materials are also available from Ausimont S.p.A. in Italy and from Federal State Unitary Enterprise S.V. Lebedev Institute of Synthetic Rubber in Russia.
• Preferred curatives and co-curatives for use in the fluoroelastomeric or perfluoroelastomeric compositions of the present invention are those which include functionalized diphenyl compounds which include branched or straight chain alkyl, halogenated alkyl, perhalogenated alkyl, and preferably perfluoroalkyl type compounds that may or may not have one or more oxygen atoms and which may or may not be substituted, and which have at least two aminophenyl groups, preferably two aminophenol groups, but which have a sufficiently high molecular weight (extended chains) so that the melting point is preferably no greater than about 240° C., more preferably no greater than about 230° C., and most preferably to about 225° C. to thereby enhance compatibility and provide fast curing reactions of perfluoroelastomeric compositions, particularly the preferred perfluoroelastomers having cyano-type curesite monomers.
• Such curing agents are preferably diphenyl-based curatives of formula (III):
• R 3 and R 4 are independently selected to be a carbon atom or branched or straight chain carbon-based groups (which may be further substituted or unsubstituted) of from about 2 to about 22 carbon atoms in any of such chains (whether straight or branched), more preferably such chains are from 10 to 22 carbon atoms, and which groups are selected from the following exemplary groups: alkyl groups, fully or partially halogenated alkyl groups, and preferably perfluorinated alkyl groups, each of which groups may be interrupted by at least one oxygen atom, and in which branching chains may include such groups as, for example, haloalkyl, fluoroalkyl and trifluoroalkyl.
• substitutions acceptable for use in formula (III) and other formulae described herein as containing substitutable groups may be the same as noted herein for formulas (I) and (II) to the extent such substitutions may be desired for a given curing reaction.
• Z is preferably an amino, mercapto, thiphenol, sulfhydryl or hydroxyl group, with the hydroxyl group being most preferred.
• Each J is independently selected to be formula (IV):
• A may be independently selected on either side of R 3 in formula (III) to be formula (IV), a hydrogen atom, a fluorine atom, or a branched or straight chain (substituted or unsubstituted) carbon-based group which is selected from the following groups: an alkyl, a partially or fully halogenated alkyl, or perfluoroalkyl groups, more preferably a perfluoroalkyl group, of from one to about 22 carbon atoms; each of which groups may be interrupted by at least one oxygen atom, and in which branching chains may include such groups as, for example, haloalkyl, fluoroalkyl and trifluoroalkyl.
• Preferred structures where r is 0, J meets formula IV and R 3 is a carbon atom include the following structures (V) through (VII) in which q preferably ranges from 0 to 6, however q being greater than 6 is also within the scope of the invention.
• R 3 is a carbon atom
• A is CF 3 on one side of R 3
• A is a chain of varied length on the other side of R 3
• Table 1 below in accordance with the structure of the chain represented by the A group opposite the A which is CF 3 .
• the preferred compounds are similar in color and appearance but differ in melting point, providing a wider range of options for curatives in terms of compatibility and curing speed in fluoroelastomeric and perfluoroelastomeric compositions.
• Preferred exemplary structures when r is 0 in formula (III), J is as in formula IV above and R 3 is a straight or branched chain group such as alkyl, halogenated alkyl, and preferably a perfluorinated alkyl group, which may or may not contain oxygen include structures such as (VIII) and (IX) below in which the biaminophenyl groups are not in the bis position as are the structures shown above, but are in terminal positions separated by a chain providing a molecular weight which is sufficient to provide a melting point of no greater than about 240° C., more preferably no greater than about 230° C., and most preferably no greater than about 225° C.
• A may be as described above. While it is within the scope of the invention for an A group to be formula (IV), it is preferred that when J is formula (IV), only two such groups appear in curatives of formula (III) and that it is preferred in such structures that neither A is formula (IV):
• x, y and z are each independently selected to be from 0 to about 20, preferably from 0 to 10, wherein preferably x+y+z total no more than about 20, and preferably from about 9 to about 20 and L is hydrogen, halogen such as fluorine, chlorine, bromine and iodine, alkyl, halogenated alkyl and preferably perfluorinated alkyls such as trifluoromethyl, most preferably L is fluorine or trifluoromethyl.
• a further example includes:
• s is preferably 1 to about 6, and x, s and z are as previously defined, with x+s+z preferably totaling no more than about 20, and more preferably at a minimum, s is 1 and x and z are 0.
• both A groups are CF 3 , R 3 is
• R 4 is
• the J group on R 3 is F and the J group on R 4 is L, and x and z are as described below. Further examples include:
• L, x and z are as described above, however, in formula XIII, XIV, XV and XVI, it is preferred that and that x and z total no more than 19. It is also preferred that in all of the formula noted above, L is fluoro, perfluoroalkyl or perfluoroalkoxy.
• any synthesis method may be used to make the novel curatives and co-curatives of the invention and that the invention of providing functionalized diphenyl-based curatives and co-curatives which have molecular weights sufficiently high to provide a melting point of no greater than about 240° C., more preferably no greater than about 230° C., or most preferably no greater than about 225° C. are encompassed within the invention including those having formula (III) regardless of their methods of synthesis.
• Preferred reactions include reacting a perfluoroalkylacid halide, preferably a perfluoroalkyl acid fluoride, i.e., an acyl-group compound, preferably a perfluoroacyl fluoride with potassium fluoride to form an alcoholate of the initial compound.
• a perfluoroalkylacid halide preferably a perfluoroalkyl acid fluoride, i.e., an acyl-group compound, preferably a perfluoroacyl fluoride
• the potassium alcoholate reaction product is then reacted with perfluoroallyl fluorosulfate to form the perfluoroallylether of that material.
• This perfluoroallyl ether reactant product is then further reacted with an oxidizing agent, i.e., oxidized, wherein the oxidizing agent is preferably oxygen but is not limited thereto, to form a perfluoroglycidyl ether.
• an oxidizing agent i.e., oxidized, wherein the oxidizing agent is preferably oxygen but is not limited thereto.
• the perfluoroglycidyl ether which is then reacted with aluminum chloride in a fluorinated solvent, isomerizes the epoxide group on the perfluoroglycidyl ether to a ketone.
• the ketone compound is then reacted with a phenyl having functional group Z (preferably where Z is OH and the phenyl is phenol) in the presence of hydrogen fluoride to form a bisphenyl-based compound, preferably a bisphenol compound.
• a phenyl having functional group Z preferably where Z is OH and the phenyl is phenol
• Such a bisphenyl- or bisphenol-based compound is then nitrated with nitric acid (or a similar useful nitrating compound) to provide an NO 2 group on each phenyl group and form a bisnitrophenyl-based or bisnitrophenol-based compound.
• This compound is then reduced using a suitable reducing agent to form the desired compound having bisaminophenyl, preferably bisaminophenol groups each having the Z radical (preferably bisaminophenol groups) of Formula IV which is capable of curing a perfluoroelastomeric composition.
• Such an exemplary synthesis route for forming novel curatives and co-curatives according the invention may be illustrated with reference to structures such formulae V and VI and similar compounds where one A in formula III is CF 3 , R 3 is a carbon atom, J is formula IV and r is 0, includes the following basic reaction scheme wherein R′ refers to a portion of the chain that is part of the A group (CF 2 —O—CF 2 —R′) extending opposite the A which is CF 3 :
• a further exemplary reaction scheme for forming compounds according to formula (III) when R 3 is a carbon atom, r is 0, J is formula (IV), one A group is CF 3 and the other A group (referred to in the mechanism below as A′) is CF 3 O(CF 2 O) q CF 2 — such as compounds in formula (VII) and similar compounds includes a method using organomagnesium compounds.
• an alkylmagnesium halide, halogenated alkyl magnesium halide or a perfluoroalkyl magnesium halide, and preferably a perfluoromagnesium iodide such as trifluoromethylmagnesium iodide is reacted with an alkyl, halogenated alkyl or perfluorinated acyl halide (such as an A chain in formula (III)) wherein the acyl halide includes a halogenated ketone group.
• the resulting compound releases magnesium halide to leave a ketone group on the acyl halide.
• This ketone is then further reacted with a substituted phenyl compound having a Z functional group (preferably hydroxyl) to form a bisphenyl functional group (preferably bisphenol) at the ketone site, which is then nitrated and subsequently reduced in the manner noted above.
• a substituted phenyl compound having a Z functional group preferably hydroxyl
• a bisphenyl functional group preferably bisphenol
• each of the two phenyl groups may be provided to R 3 or R 4 at different locations and/or terminal locations by using known chemical substitution techniques and routes to achieve various other formulae in accordance with formula (III).
• One such substitution route is shown in Evers, noted above herein, which obtains fluorocarbon bisaminophenols (some of which are represented by formula (III)) by reacting diiodoperfluoroalkane intermediates with iodophenyl acetate, hydrolyzing the product to obtain a bisphenol, nitrating and then reducing the dinitrobisphenol to obtain a bisaminophenol.
• curing agents or more than one curing agent depending on the cure site monomers present, such as an organic peroxide, an organometallic compound such as an organotin, diamines, amidines, conventional bisaminophenols and/or bisaminothiophenols, etc. or mixtures thereof.
• perfluoropolymers may be cured using radiation curing technology as an assist or to cure other curesites not cured by the curatives and co-curatives of the invention.
• the amount and type of curative or co-curing agent according to the invention which should be used should be chosen to optimize the desired properties of the cured fluoroelastomer or perfluoroelastomer (including its resistance to chemical attack, specific elongation-at-break, resistance to compression set, flexural modulus, tear strength, hardness and the like).
• the amount used will depend on the degree of crosslinking desired, the type and number of cure sites to be cured by the inventive curatives, the number of other cure sites to be cured by other curatives not within the scope of the invention, and the cure rate desired.
• a preferred amount of curative is an amount as much as equivalent to an amount in slight excess of the amount required to react with those curesites present in the fluoroelastomeric or perfluoroelastomeric composition which are capable of reacting with the curatives and co-curatives of the invention.
• about 0.1 to about 10 parts by weight of the curing agent per about 100 parts of fluoropolymer or perfluoropolymer is used, more preferably about 1 to about 4 parts by weight.
• the amount is preferably less, since other cure reactions are occurring, however, that too depends on the number of sites and other parameters noted above.
• the invention includes amidine-based or amidoxime-based curatives which may function as curatives or co-curatives, and also as cure accelerators, and may be employed either alone or with the biphenyl-based curatives and co-curatives of the invention as described herein or with other curatives not within the invention, or used to further accelerate the rate of cure of the biphenyl-based curatives and co-curatives of the invention nor other curatives outside of the invention within perfluoroelastomeric compositions.
• amidine-based or amidoxime-based curatives which may function as curatives or co-curatives, and also as cure accelerators, and may be employed either alone or with the biphenyl-based curatives and co-curatives of the invention as described herein or with other curatives not within the invention, or used to further accelerate the rate of cure of the biphenyl-based curatives and co-curatives of the invention nor other curatives outside of the invention within perfluoroelastomeric compositions.
• Suitable amidine and amidoxime curatives and accelerators include monoamidines, monoamidoximes and bisamidines as described herein.
• Other cure accelerators known in the art such as organic or inorganic ammoniums salts, e.g.
• perfluoroctonaoate ammonium perfluoroacetate, ammonium thiocyanate, and ammonium sulfamate; urea; t-butyl carbamate; acetaldehyde ammonia; tetraalkylphosphonium salts, tetraalkylammonium salts, and trialkylsulfonium salts, such as benzyltriphenylphosphonium chloride, benzyltriphenylphosphonium bromide, benzyltriphenyl-phosphonium phenol ate of bisphenol AF, tetrabutylammonium hydrogen sulfate, and tetrabutylammonium bromide may also be used in conjunction with the novel biphenyl-based curatives and co-curatives of the invention if desired.
• amidine- and amidoxime-based cure accelerators described herein be used to accelerate the cure of the biphenyl-based curatives and co-curatives of the invention.
• the preferred accelerators for the biphenyl-based curatives and co-curatives of the present invention are amidine-based and amidoxime-based cure accelerators, which also may themselves function as independent curatives or co-curatives in perfluoroelastomeric compositions.
• amidine-based and amidoxime-based materials include monoamidines and monoamidoximes of the following formula (I) and bisamidines of formula (II) described further below.
• the monoamidines and monoamidoximes may be represented by formula (I)
• Y may be a substituted alkyl, alkoxy, aryl, aralkyl or aralkoxy group or an unsubstituted or substituted fully or partially halogenated alkyl, alkoxy, aryl, aralkyl or aralkoxy group having from about 1 to about 22 carbon atoms.
• Y may also be, and preferably is, a perfluoroalkyl, perfluoroalkoxy, perfluoroaryl, perfluoroaralkyl or perfluoroaralkoxy group of from 1 to about 22 carbon atoms and more preferably a perfluoroalkyl or perfluoroalkoxy group of from about 1 to about 12 carbon atoms, and more preferably from 1 to 9 carbon atoms; and R 1 may be hydrogen or substituted or unsubstituted lower alkyl or alkoxy groups of from one to about 6 carbon atoms, or an amino group.
• R 2 may be independently any of the groups listed above for R 1 or hydroxyl.
• Substituted groups for Y, R 1 or R 2 include, without limitation, halogenated alkyl, perhalogenated alkyl, halogenated alkoxy, perhalogenated alkoxy, thio, amine, imine, amide, imide, halogen, carboxyl, sulfonyl, hydroxyl, and the like.
• Preferred embodiments include those in which R 2 is hydroxyl, hydrogen or substituted or unsubstituted alkyl or alkoxy groups of from 1 to 6 carbon atoms, more preferably hydroxyl or hydrogen.
• R is hydrogen, amino or a substituted or unsubstituted lower alkyl of from 1 to 6 carbon atoms while R 2 is hydrogen or hydroxyl.
• R 1 is hydrogen.
• Further preferred embodiments include those in which Y is perfluoroalkyl, perfluoroalkoxy, substituted or unsubstituted aryl groups and substituted or unsubstituted halogenated aryl groups having the chain lengths as noted above.
• Exemplary monoamidine-based and monoamidoxime-based curatives according to formula (I) include perfluoroalkylamidines, arylamidines, perfluoroalkylamidoximes, arylamidoximes and perfluoroalkylamidrazones. Specific examples include perfluorooctanamidine, heptafluorobutyrylamidine, benzamidine, trifluoromethylbenzamidoxime, and trifluoromethoxylbenzamidoxime. Curatives as noted according to formula (I) may be used alone or in combinations, such as combinations of the foregoing exemplary compounds.
• the curatives according to formula (I) are preferably capable of curing perfluoroelastomeric compositions, particularly those with at least one cyano curesite monomer.
• the curatives according to formula (I) of the present invention are also monoamidine-based and monoamidoxime-based cure accelerators which are capable of accelerating the cure of perfluoroelastomeric compositions comprising at least one cyano curesite monomer, and more preferably compositions which also include diphenyl-based curatives (including the novel diphenyl-based curatives of the invention), such as bisaminophenol and its derivatives.
• Suitable examples of monoamidines include benzamidines and perfluoroalkyl amidines.- Particularly suitable examples are perfluorooctanamidine and perfluoroheptanamidine.
• the invention also includes bisamidine-based curative and cure accelerators for fluoroelastomeric and perfluoroelastomeric compositions represented by formula (II):
• D may be unsubstituted or substituted fully or partially halogenated alkyl, alkoxy, aryl, aralkyl or aralkoxy groups having from about 1 to about 22 carbon atoms, or more preferably perfluoroalkyl, perfluoroalkoxy, perfluoroaryl, perfluoroaralkyl, or perfluoroaralkoxy groups of from 1 to about 22 carbon atoms and more preferably a perfluoroalkyl or perfluoroalkoxy group of from about 1 to about 12 carbon atoms.
• R 1 and R 2 are as defined above with respect to formula (I), however, in formula (II), R 2 is not hydroxyl, it is independently selected to be the same as R 1 noted above. Further, D, R 1 and R 2 may each be substituted by one of more of the groups noted above with respect to formula (I). Most preferably herein in formula (II), both R 1 and R 2 are hydrogen.
• Oxygen atoms are preferably included in the form of ether linkages in Y, R 1 and R 2 While it is preferred that Y is straight or branched, it is also within the scope of the invention that Y could be a cyclic or aromatic structure, which is capable of being substituted as noted above.
• D is a fluorinated, more preferably perfluorinated. If D is only partially halogenated, however, it is preferred that the carbon atoms adjacent the amidine groups each have two hydrogen substituents to stabilize the compound. Oxygen atoms in D are preferably also in the form of ether linkages. While it is preferred that D is straight or branched chain, it is also within the scope of the invention that D is a cyclic or aromatic structure, which may be further substituted. Particularly suitable examples of such bisamidines include perfluorosuberamidine and perfluorosebacamidine.
• Suitable perfluoroalkyl monoamidines and bisamidines can be purchased from SynQuest Laboratories, Inc. of Alachua, Fla. Such materials are commercially available from Federal State Unitary Enterprise S.V. Lebedev Institute of Synthetic Rubber in Russia.
• the bisamidines of the invention can be used as cure accelerators capable of accelerating the cure of perfluoroelastomers, particularly when the perfluoroelastomeric composition includes at least one cyano curesite monomer.
• Preferred exemplary bisamidines according to the invention include perfluorosuberamidine and perfluorosebacamidine.
• the amount is chosen may be based upon the particular perfluoroelastomer chosen, the curatives and/or co-curatives chosen and the desired cure properties, such as the time necessary to develop a minimum specified Mooney viscosity, the ability of the composition to resist deformation, and a maximum specified torque measured by a moving die rheometer.
• Suitable amounts include about 0.1 to about 5 parts of accelerator per about 100 parts of perfluoropolymer.
• the invention is not restricted with respect to any particular synthesis method for making these compounds. Any chemical synthesis and/or use of commercially available monoamidines, monoamidoximes and bisamidines are acceptable. However, the present invention does include a novel synthesis method as described herein.
• an alkyl acid i.e., an organic acid such as a carboxylic acid containing compound
• halogenated alkyl acid and preferably a perfluorinated alkyl acid is first converted to a nitrile form by combining the alkyl acid (or similar compound as noted) with an alcohol, such as an alkanol, e.g. methanol or ethanol in the presence of an inorganic acid such as sulfuric acid.
• the mixture is boiled, washed with water and dried, preferably using an suitable material such as MgSO 4 .
• the resulting product is an alkylester, halogenated alkyl ester or perfluoroalkyl ester which is then reacted with a nitrogen containing reactant such as ammonia, preferably ammonia gas.
• a reaction is allowed to proceed with control of the reaction temperature to produce a carboxyamide structure, such as an alkylcarboxyamide.
• This reaction product is then combined with a dehydrating agent, such as, for example, phosphorus pentaoxide, mixed and refluxed under heat and the product is converted to an alkyl nitrile, such as cyano-functional alkyls including an alkylcyano, halogenated cyano or perfluoroalkyl cyano compounds.
• the alkyl nitrile compound is then added to a reaction chamber filled with at least one nitrogen containing compound, such as preferably an amine compound or ammonia in liquid or gas form, preferably in liquid form. It is preferred that the nitrogen-containing compound such as ammonia is present in excess, preferably about 10 fold excess, with respect to the added alkyl nitrile (preferably cyano-functional) compound.
• the temperature is raised, preferably slowly, to about ambient temperature and excess nitrogen containing compound (such as ammonia) is removed.
• Solid white product is typically the resulting compound which is an alkyl, halogenated alkyl or perfluorinated alkyl group having a monoamidine structure.
• any method known or to be developed may be employed in making the bisamidines, monoamidines or monoamidoximes of the invention without departing from the scope of the invention.
• the resulting monoamidines and monoamidoximes of the invention are useful as curatives and are capable of curing or accelerating the cure of perfluoroelastomeric compositions as noted above.
• Preferred compounds made according to the above method include perfluoroheptanamidine.
• the perfluoroelastomeric composition is mixed or blended with any of the above additives by any conventional means or apparatus, including with two-roll mills and internal mixers.
• the composition may be blended using an internal mixer such as those commercially available from Banbury, C.W. Bradender Instruments, Inc. of Ralphensack, N.J. and from Morijama of Farmingdale, N.Y.
• the curative(s) and co-curative(s) of the invention and/or the cure accelerators of the invention are added once all of the other ingredients desired are blended, however, it should be understood that the order in which such materials are provided is not limiting the scope of the invention.
• the curable compositions may then be processed and cured/crosslinked by application of heat and/or pressure to form an elastomeric part, such as a seal. After curing, postcuring may be desirable to enhance physical properties and is also within the scope of the invention.
• a bisaminophenol derivative according to formula (III) (2,2-bis[3-amino-4-hydroxyphenyl]4,7,9,11 tetraoxa-1,1,1,3,3,5,5,6,6,8,8,10,10,12,12,12-hexadecafluorododecane) was prepared in which R 3 is a carbon atom, r is 0, J is a structure as in formula (IV), one A is —CF 3 and the other A is —CF 2 OCF 2 CF 2 (OCF 2 ) 2 OCF 3 .
• Such structure is shown above in representative form in formula (V).
• a perfluorinated polyether ketone was first formed in accordance with an epoxide-ketone route as described herein.
• a flask protected by a continuous flow of dry nitrogen gas was charged with potassium fluoride in an amount of 11.6 g (0.2 mole) and 100 ml Diglyme that had already been dried by distillation from CaH 2 .
• the mixture was stirred for 15 minutes.
• To this mixture was added at room temperature with good stirring 60 g (0.19 mole) of 3,5,7-trioxa-2,2,4,4,6,6,8,8,8-nonafluorooctanoyl fluoride were added for 1 to 1.5 hours, at room temperature and with adequate stirring.
• the lower layer was dried by distillation from P 2 O 5 to obtain crude perfluoroallyl ether (4,7,9,11-tetraoxa-1,1,2,3,3,5,5,8,8,10,10,12,12,12-hexadecafluorododecene) in 95% yield.
• the crude perfluoroallyl ether was fractionally distilled and a fraction boiling at 88° C. was collected and identified by F 19 NMR, IR spectroscopy (absorption band at 1795 cm ⁇ 1 corresponding to —CF ⁇ CF 2 ) and elemental analysis.
• the elemental analysis is as follows:
• the pure perfluoroketone (4,7,9,11-tetraoxa-1,1,1,3,3,5,5,6,6,8,8,10,10,12,12,12-hexadecafluorododecan-2-one) was obtained by fractional distillation at b.p. of 114° C. Its identity was confirmed by F 19 NMR and its purity by gas-liquid chromatography. The final reaction to form the perfluoroketone is shown representatively below:
• a metal ampoule was charged with 94 g of phenol, 240 g of perfluoroketone and 100 g of hydrogen fluoride, sealed and heated for 10 hours at a temperature of 95° C.
• the hydrogen fluoride was removed by distillation and the solid bis-phenol was purified by recrystallization from toluene and chloroform.
• the yield was pure bisphenol (2,2-bis[4-hydoxyphenyl]4,7,9,11-tetraoxa-1,1,1,3,3,5,5,6,6,8,8,10,10,12,12,12-hexadecafluorododecane) at 89%.
• the structure was confirmed by F 19 NMR.
• a four-neck flask was fitted with an agitator, reflux condenser, dropping funnel and thermometer.
• a solution of 39.2 g of the above bisphenol product and 0.1 g NaNO 2 in 130 ml glacial acetic acid was prepared in the flask. With the solution maintained at 40-45° C., a solution of nitric acid and 20 ml glacial acetic acid was added. When the addition was completed the reaction mixture was heated for 2 hours at a temperature of 60° C., then for 3 hours at a temperature of 80° C. Water was added and the yellow-red oil that resulted was separated, dissolved in toluene and dried over MgSO4.
• Toluene solvent was distilled off at 200-300 mm Hg pressure using a water-jet pump.
• the residual bisaminophenol product (2,2-bis[3-nitro-4-hydroxyphenyl]4,7,9,11-tetraoxa-1,1,1,3,3,5,5,6,6,8,8,10,10,12,12,12-hexadecafluorododecane) was obtained in an amount of 54.7 g for a 81.1% yield.
• a four-neck flask was fitted with an agitator, reflux condenser, dropping funnel and thermometer.
• a solution of the bisaminophenol above in 100 ml ethanol was prepared in the flask and 1.5 g catalyst was added (5% Pt on carbon). With agitation, 12 g of 100% hydrogen peroxide was added and the mixture was refluxed for 4 hours. The mixture was cooled filtered to remove the catalyst and diluted with three volumes of water. The aqueous mixture was acidified with acetic acid to a pH below 6. The precipitated product was collected by filtration, air-dried and recrystallized from ethyl acetate.
• a flask containing 28.8 g Mg and a few crystals of iodine was heated with stirring to 60° C. until the iodine color disappeared.
• the flask was cooled to room temperature and 300 ml of diethyl ether were added.
• the flask cooled to ⁇ 40° C. and 19.0 g of CF 3 I were slowly added dropwise over a period of 3 hours to produce a solution containing 8.8 g (40% yield) of CF 3 MgI.
• the temperature was raised to 30° C., and 3,5,7-trioxa-2,2,4,4,6,6,8,8,8-nonafluorooctanoyl chloride) was added over a period of one hour while stirring.
• various perfluoroelastomeric compositions were prepared using as a base perfluoroelastomer, tetrapolymers prepared by batchwise polymerization in aqueous emulsion as described in detail in WO 00/08076, incorporated herein by reference.
• the monomers in the terpolymer included tetrafluoroethylene, perfluoromethylvinyl ether and two curesite monomers, a secondary cyano curesite monomer, CF 2 ⁇ CFO(CF 2 ) 3 OCF(CF 3 )CN and a primary cyano curesite monomer, CF 2 ⁇ CFOCF 2 CF(CF 3 )O(CF 2 ) 2 CN.
• Polymer A redox type, 45 Mooney viscosity
• Polymer B non-redox, 65 Mooney viscosity
• Polymer C non-redox, 64 Mooney viscosity
• Curatives A and B were obtained from Federal State Unitary Enterprise S.V. Lebedev Institute of Synthetic Rubber in Russia. Curatives A and B each had the structure: (2,2-bis[3-amino-4-hydroxylphenol]R).
• R was —CF 2 (OCF 2 ) 3 OCF 3
• Curative A had a melting point of 120° C. and a molecular weight of 630 daltons.
• Curative B R was —CF 2 OCF 2 CF 2 (OCF 2 ) 2 OCF 3 and Curative B had a melting point of about 142 to 145° C. and a molecular weight of 680 daltons.
• carbon black specifically Carbon Black N990.
• Test specimens were made by mixing a tetrapolymer and the curatives to form a perfluoroelastomeric composition, and adding carbon black to that composition, using a Brabender 100 g or 600 g internal mixer.
• the compounds, upon mixing, were shaped into O-ring preforms, molded to cure the performs into seals and then postcured into Size 214O-rings in accordance with the cure and postcure conditions noted in the Tables below.
• the rings were tested for tensile properties using ASTM-D-412, Method B, and the following parameters were recorded: T B (tensile at break in MPa); E B (elongation at break in %); and M 100 (modulus at 100% elongation in MPa).
• Compression set of O-ring samples was determined in accordance with ASTM-D-395, Method B. Cure characteristics were measured using a Monsanto MDR 2000 under the following conditions: Moving die frequency: 1.6667 Hz Oscillation amplitude: 0.5 deg arc Temperature: as indicated in Tables herein Sample size: disks of 1.6 inch diameter, thickness of 0.17 inch and 9.5 g weight Duration of test: 60 minutes
• M H maximum torque level in units of Nm
• M L minimum torque level in unites of Nm
• t s 2 minutes to 0.23 Nm rise above M L
• t c 90 minutes to 90% of M H .
• Tables 3 and 4 are directed to use of novel curatives, Curatives A and B, and to use of novel amidines and bisamidines as cure accelerators for those novel curatives as well as for standard BOAP, and includes the use of BOAP alone as a comparative sample (Sample No. 11).
• the compositions include a tetrapolymer, one of Polymers A-D, Carbon Black N990 and Fluorogard PCA.
• the cure characteristics were MDR, 1 h@ 160° C.
• Table 3 includes the formulations and Table 4 includes the data related to those formulations.
• Table 5 includes data showing the effects of use of bisamidines and monoamidines of the invention as curatives (Samples Nos. 13-19). Each of these compositions is based on Polymer A, and includes Fluorogard PCA and Carbon Black N990 as additives. In each of Samples 13-19, 100 phr of Polymer A were mixed with 25 phr carbon black and 1.5 phr Fluorogard PCA. The varying amounts of curatives are shown in Table 5 along with the resulting data for each perfluoroelastomeric composition. In Table 5, when the post cure sequence G is used, it represents increasing the temperature from 25° C. to 94° C. over 1.5 h and then to 149° C. over 1 h.
• the post cure is then held at 149° C. for 0.5 h and then further heated to 204° C. over 1 h and held at 204° C. for 18 h. The temperature is then increased to 260° C. over 1 h and held at that temperature for 18 h. The post cure is then cooled to 25° C. over 2 h.
• Tables 6 and 7 include compositions and data, respectively, directed to the effect of bisamidines and monoamidines as cure accelerators for BOAP containing perfluoroelastomeric compositions.
• Samples Nos. 20-30 Polymers A, B and D compositions each including 100 phr of the polymer, 25 phr Carbon Black N990, 1.5 phr Fluorogard PCA and varying amounts of BOAP are cured with the amidines as indicated.
• the data demonstrate the acceleration affect of the amidine cure accelerators of the invention.
• the novel curatives of the Example provide comparable physical properties to standard use of BOAP, but due to the low melting points and higher compatibility of the Curatives A and B and the fast acting amidine curatives and accelerators, the curatives and accelerators of the invention provide faster, more reliable curing of the perfluoropolymer to form the perfluoroelastomer.
• Example 5 Further Samples were prepared using polymers having the same monomers as used in Example 5, however, the polymers in this Example were mixtures of two different molecular weight chains Polymer B noted above in Example 5. The formulations are shown in Table 8 below. The polymers were polymerized in the same manner and Mooney viscosity was measured at 100° C. on a TechPro® viscTECH TPD-1585 viscometer. To the polymers noted above, used in these compositions, were added heptafluorobutyrylamidine as a curative and as a cure accelerator. The heptafluorobutyrylamidine was obtained from SynQuest Laboratories, Inc., Alachua, Fla. All other components are as described above in Example 5.
• Test specimens were made by mixing a tetrapolymer and the curatives to form a perfluoroelastomeric composition, and adding carbon black to that composition, using a Brabender internal mixer.
• the compounds, upon mixing, were shaped into O-ring preforms, molded to cure the performs into seals and then postcured into Size 214 O-rings in accordance with the cure and postcure conditions noted in Table 9 below.
• the rings were tested for tensile properties using ASTM-D-412, Method B, and the following parameters were recorded: T B (tensile at break in MPa); E B (elongation at break in %); and M 100 (modulus at 100% elongation in MPa).
• Compression set of O-ring samples was determined in accordance with ASTM-D-395, Method B. Cure characteristics were measured using a Monsanto MDR 2000 under the following conditions: Moving die frequency: 1.6667 Hz Oscillation amplitude: 0.5 deg arc Temperature: as indicated in Tables herein Sample size: disks of 1.6 inch diameter, thickness of 0.17 inch and 9.5 g weight Duration of test: 60 minutes
• Table 9 includes the data directed to the effect of the monoamidine noted as a curative for a perfluoroelastomeric composition and as a cure accelerator for a BOAP-containing perfluoroelastomeric composition.
• the Polymer B compositions each included 100 phr of polymer and 25 phr Carbon Black N990 and BOAP as noted in Table 8 which were cured and/or accelerated with the amidine as indicated.
• the information in Table 8 are indicated in parts per hundred.
• Sample 31 represents the control.
• the percentage measurement indicates percentage deflection and the physical property data is based on post cured samples. The data demonstrate the curative and acceleration affect of the amidine cure accelerators of the invention.

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