Fluorinated resorcinol and hydroquinone analogs as curing agents for fluoroelastomers

Abstract

The composition includes a fluorinated resorcinol or hydroquinone curing agent of Formula 1: R1 and R5 are independently H, halogen, optionally partially or fully halogenated C1-18 alkyl, optionally partially or fully halogenated C1-18 alkoxy, or X. R < 2 > to R < 4 > are independently OH, H, halogen, C1-18 alkyl which is optionally partially or completely halogenated, C1-18 alkoxy which is optionally partially or completely halogenated or X. And at least one of R2, R3, and R4 is OH. And no more than three of R1-R5 are halogens. X is Formula 2 or Formula 3 as disclosed herein. Also disclosed herein are curable fluoroelastomer compositions, fluoroelastomer masterbatches, curing agent and cure accelerator mixtures, salts, and methods of curing a polyhydroxy curable fluoroelastomer including a fluorinated resorcinol or hydroquinone curing agent of Formula 1. # imgabs0 #

Description

[0001] Citation of Related Applications

[0002] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 408,349, filed on September 20, 2022, which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present disclosure relates to curing agents for fluoroelastomers and more particularly to fluorinated resorcinol and hydroquinone analogs useful as curing agents for fluoroelastomers. Background Art

[0004] Fluoroelastomers have excellent heat resistance, oil resistance and chemical resistance and have been widely used in sealing materials, containers and hoses. Examples of fluoroelastomers include copolymers comprising vinylidene fluoride (VF2) monomer units and at least one other copolymerizable fluorine-containing monomer such as hexafluoropropylene (HFP), tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE), vinyl fluoride (VF) or fluorovinyl ether such as perfluoro(alkyl vinyl ether) (PAVE) monomer units. Specific examples of PAVE include perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether) and perfluoro(propyl vinyl ether). Other fluoroelastomers include copolymers of TFE with hydrocarbon olefins such as ethylene or propylene. Perfluoroelastomers, which are copolymers of TFE and PAVE, are known.

[0005] In order to fully develop the physical properties of the elastomer used in molded elastomeric articles, the polymer must be cured, i.e., vulcanized or crosslinked. This is usually accomplished in conjunction with the molding process by mixing the uncured polymer with a multifunctional curing agent, heating and molding the mixture into the shape of the desired article, and then further heating the resulting molding mixture to promote the crosslinking reaction of the curing agent with the polymer to produce a cured fluoroelastomer article.

[0006] Certain grades of fluoroelastomers, such as certain copolymers of VF2 / HFP or VF2 / HFP / TFE that do not include a cure site monomer, can be cured using a polyol as a curing agent. 2,2-Bis(4-hydroxyphenyl)hexafluoropropane, often referred to as bisphenol AF (BPAF), is a widely used curing agent for polyol-curable grades of fluoroelastomers. As a curing agent for polyol-curable grades of fluoroelastomers, BPAF provides good processing of the fluoroelastomer during molding into articles and imparts good properties to the cured fluoroelastomer articles. With respect to processing during molding, BPAF does not cause excessive "scorching", i.e., does not cure too quickly when the article is being molded, but provides a desirable short cure time once the article being molded begins to cure. In the cured fluoroelastomer article, BPAF imparts desirable low "compression set" properties to the fluoroelastomer. Compression set is a common measure of the ability of an elastomer to recover to nearly its original thickness after being compressed at elevated temperatures.

[0007] Current restrictions proposed by the European Union include that BPAF is a class of compounds with endocrine disrupting properties. Therefore, it is desirable to use curing agents other than BPAF. In U.S. Patent No. 6,610,790, a number of compounds are listed as curing agents for fluoroelastomers in addition to BPAF, including resorcinol, hydroquinone, and certain alkyl-substituted resorcinols and hydroquinones. However, the other curing agents listed in U.S. Patent No. 6,610,790 do not provide the good processing and compression set properties that BPAF can provide. Summary of the invention

[0008] The fluorinated resorcinol and hydroquinone analogs disclosed herein provide a good balance of processability and compression set properties as alternative curing agents to BPAF in the cure of fluoroelastomers.

[0009] In one embodiment, the curable fluoroelastomer composition comprises a polyhydroxy curable fluoroelastomer, a curing agent of Formula 1, and an acid acceptor.

[0010]

[0011] R1 and R5 are independently selected from the group consisting of: H, halogen, C which may be partially or fully halogenated 1-18 Alkyl, partially or fully halogenated C 1-18 alkoxy and X, and R2, R3 and R4 are independently selected from the group consisting of OH, H, halogen, C which may be partially or fully halogenated 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy and X, provided that at least one of R2, R3 and R4 is OH, and provided that no more than 3 of R1, R2, R3, R4 and R5 are halogen.

[0012] X is selected from the group consisting of formula 2 and formula 3:

[0013]

[0014] R6, R7, R8, R9 and R 10 independently selected from the group consisting of: H; C which may be partially or fully halogenated 1-18 Alkyl; C may be partially or fully halogenated 1-18 alkoxy; phenyl which may be partially or fully fluorinated, acetyl or methylsulfonyl which may be substituted by alkyl or aryl or which may be partially or fully halogenated; nitro; nitrile; and halogen, provided that N may be substituted at exactly one of C2, C3 or C4, in which case the corresponding R6, R7 or R8 is absent; R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 independently selected from the group consisting of: H, C which may be partially or fully halogenated 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy, nitro, nitrile and halogen, provided that R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 One of them is -(Y) n - connected single bond; Y is selected from the group consisting of: -SO2-, -C(O)-, -C(CF3)2- and -O- and n is 0 or 1, provided that at least one of R1, R2, R3, R4 and R5 is fluorine, fluorine-containing C 1-18 Alkyl, fluorinated C 1-18 alkoxy or X, provided that when X is present and R1, R2, R3, R4 and R5 are not fluorine, fluorine-containing C 1-18 Alkyl or fluorinated C 1-18 In the case of alkoxy, R6, R7, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 At least one of them is fluorine, fluorine-containing C 1-18 Alkyl or fluorinated C 1-18Alkoxy.

[0015] In one embodiment of the composition, at least one of R1 and R5 is H.

[0016] In another embodiment of the composition, when at least one of R1, R2, R3, R4 and R5 is an adjacent substituent of OH, it is H.

[0017] In another embodiment of the composition, no more than one of R1, R2, R3, R4 and R5 is X.

[0018] In another embodiment of the composition, no more than 2 of R1, R2, R3, R4, and R5 are halogen.

[0019] In another embodiment of the composition, only one of R2, R3 and R4 is OH.

[0020] In another embodiment of the composition, R2 or R4 is OH.

[0021] In another embodiment of the composition, R1 and R5 are selected from the group consisting of: H, fluorine, C which may be partially or fully fluorinated. 1-18 Alkyl, partially or fully fluorinated C 1-18 Alkoxy and X; and R2, R3 and R4 are independently selected from the group consisting of: OH, H, fluorine, C which may be partially or fully fluorinated 1-18 Alkyl, partially or fully fluorinated C 1-18 Alkoxy and X.

[0022] In another embodiment of the composition, one of R1, R2, R3, R4, and R5 is X and X is Formula 2.

[0023] In another embodiment of the composition, R6, R7, R8, R9 and R 10 independently selected from the group consisting of: H, fluorine, C which may be partially or fully fluorinated 1-6 Alkyl and partially or fully fluorinated C 1-6 Alkoxy, and R6, R7, R8, R9 and R 10 At least one of them is fluorine, C which may be partially or completely fluorinated 1-6 Alkyl or partially or fully fluorinated C 1-6 Alkoxy.

[0024] In another embodiment of the composition, R6, R7, R8, R9 and R 10 are independently selected from the group consisting of: H, fluorine, perfluoromethyl and perfluoromethoxy, and R6, R7, R8, R9 and R 10At least one of them is fluorine, perfluoromethyl or perfluoromethoxy.

[0025] In another embodiment of the composition, n is zero.

[0026] In another embodiment of the composition, -Y- is -O-.

[0027] In another embodiment of the composition, the curing agent is selected from the group consisting of:

[0028]

[0029] In another embodiment of the composition, the composition contains about 0.1 parts by weight to about 10 parts by weight of the curing agent per 100 parts by weight of the fluoroelastomer.

[0030] In another embodiment of the composition, the polyhydroxy curable fluoroelastomer is a copolymer of hexafluoropropylene and vinylidene fluoride.

[0031] In another embodiment of the composition, the polyhydroxy curable fluoroelastomer is a terpolymer of hexafluoropropylene, vinylidene fluoride and tetrafluoroethylene.

[0032] In another embodiment of the composition, the acid acceptor is selected from the group consisting of powdered magnesium oxide, calcium hydroxide, and combinations thereof.

[0033] In another embodiment of the composition, the curable fluoroelastomer composition is free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

[0034] In another embodiment, a fluoroelastomer masterbatch comprises a polyhydroxy curable fluoropolymer and a curing agent of Formula 1. The curing agent is present in a concentration of about 1 wt % to about 50 wt %.

[0035] In one embodiment of the fluoroelastomer masterbatch, the concentration of the curing agent is from about 20 wt % to about 40 wt %.

[0036] In another embodiment, the curing agent and curing accelerator mixture comprises a curing agent of Formula 1 and a curing accelerator selected from the group consisting of a quaternary phosphonium salt, a quaternary ammonium salt, and a tertiary sulfonium salt.

[0037] In one embodiment of the mixture of curing agent and curing accelerator, the curing accelerator is a tertiary sulfonium salt.

[0038] In another embodiment of the mixture of curing agent and curing accelerator, the curing accelerator is a quaternary ammonium salt.

[0039] In another embodiment of the mixture of curing agent and curing accelerator, the quaternary ammonium salt is tetrabutylammonium hydrogen sulfate.

[0040] In another embodiment of the mixture of curing agent and curing accelerator, the curing accelerator is a quaternary phosphonium salt.

[0041] In another embodiment of the mixture of curing agent and curing accelerator, the quaternary phosphonium salt is benzyltriphenylphosphonium chloride.

[0042] In yet another embodiment, the salt used as a curing agent and curing accelerator for the fluoroelastomer comprises a quaternary phosphonium salt or a quaternary ammonium salt derived from the compound of Formula 1.

[0043] In one embodiment of the salt, the cure accelerator is a quaternary ammonium salt.

[0044] In another salt embodiment, the quaternary ammonium salt is tetrabutylammonium hydrogen sulfate.

[0045] In another embodiment of the salt, the cure accelerator is a quaternary phosphonium salt.

[0046] In another salt embodiment, the salt is a benzyltriphenylphosphonium salt.

[0047] In another embodiment, a method of curing a polyhydroxy curable fluoroelastomer comprises forming a curable fluoroelastomer composition comprising a polyhydroxy curable fluoroelastomer, a curing agent of Formula 1, and an acid acceptor, and heating the curable fluoroelastomer composition to cure the polyhydroxy curable fluoroelastomer.

[0048] In one embodiment of the method, the curable fluoroelastomer composition is free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

[0049] In another embodiment, the article is cured by the method.

[0050] In one embodiment of the article, the article is free or substantially free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

[0051] In another embodiment, the compound has Formula 1A.

[0052]

[0053] One of R1 and R2 is H and the other is OH. One of R3 and R4 is H and the other is selected from the group consisting of Formula 2A and Formula 3A.

[0054]

[0055] R5, R6, R7, R8 and R9 are independently selected from the group consisting of: H, F, CF3, partially or fully fluorinated phenyl, OCF3, CH3, nitro and nitrile; provided that at least one of R5, R6, R7, R8 and R9 is selected from the group consisting of: F, CF3, partially or fully fluorinated phenyl and OCF3; provided that when R5, R6, R7, R8 and R9 are independently selected from the group consisting of H and F, at least two are H and at least two are F; provided that when R1 is OH, R3 is formula 2A, and R5, R6, R7, R8 and R9 are independently selected from the group consisting of H and CF3, at least one of R6 and R8 is H; and provided that N can be substituted at exactly one of C2, C3 or C4, in which case the corresponding R5, R6 or R7 is not present.

[0056] In one embodiment of this compound, R1 is OH and R2 is H.

[0057] In some embodiments, the ring in Formula 2A is a benzyl ring.

[0058] In some embodiments, N is substituted at exactly one of C2, C3, or C4, and the ring in Formula 2A is a pyridinyl ring.

[0059] Other features and advantages of the invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate by way of example the principles of the invention. DETAILED DESCRIPTION

[0060] Exemplary fluorinated resorcinol and hydroquinone analogs are provided that provide a good balance of processability and compression set properties as alternative curing agents to BPAF in the cure of fluoroelastomers.

[0061] In an exemplary embodiment, the curing agent provides curing properties and cured fluoroelastomer properties similar to BPAF as a curing agent. Such curing properties can be measured by a moving die rheometer (MDR) and may include, but are not limited to, minimum S' torque (M L ), the maximum S' torque (M) achieved during a specified period of time H ), from M L Increase the (scorch) time (ts1) of one unit S' torque, from M L Increase the (scorch) time (ts2) of two units of S' torque, from M L Increase S' torque by 50% to M H (Curing) time (t 50 ) and / or from M L 90% increase in S' torque to M H (Curing) time (t90 ). The properties of such cured fluoroelastomers may include, but are not limited to, compression set resistance, tensile strength (TS), elongation at break (EB), and 100% elastic modulus (M100) and / or fluid aging properties.

[0062] In an exemplary embodiment, the curing agent has Formula 1:

[0063]

[0064] wherein R1 and R5 are independently selected from the group consisting of: H, halogen, C which may be partially or fully halogenated 1-18 Alkyl, partially or fully halogenated C 1-18 alkoxy and X, and R2, R3 and R4 are independently selected from the group consisting of OH, H, halogen, C which may be partially or fully halogenated 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy and X, provided that at least one of R2, R3 and R4 is OH, and provided that no more than 3 of R1, R2, R3, R4 and R5 are halogen; wherein X is selected from the group consisting of Formula 2 and Formula 3:

[0065]

[0066] Among them, R6, R7, R8, R9 and R 10 independently selected from the group consisting of: H; C which may be partially or fully halogenated 1-18 Alkyl; C may be partially or fully halogenated 1-18 alkoxy; phenyl which may be partially or fully fluorinated, acetyl or methylsulfonyl which may be substituted with alkyl or aryl or which may be partially or fully halogenated; nitro; nitrile; and halogen, provided that N may be substituted at exactly one of C2, C3 or C4, in which case the corresponding R6, R7 or R8 is absent, such that the ring in formula 2 is a pyridyl ring; and R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 independently selected from the group consisting of: H, C which may be partially or fully halogenated 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy, nitro, nitrile and halogen, provided that R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R17 and R 18 One of them is -(Y) n - connected single bond; Y is selected from the group consisting of: -SO2-, -C(O)-, -C(CF3)2- and -O- and n is 0 or 1, provided that at least one of R1, R2, R3, R4 and R5 is fluorine, fluorine-containing C 1-18 Alkyl, fluorinated C 1-18 alkoxy or X, provided that when X is present and R1, R2, R3, R4 and R5 are not fluorine, fluorine-containing C 1-18 Alkyl or fluorinated C 1-18 In the case of alkoxy, R6, R7, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 At least one of them is fluorine, fluorine-containing C 1-18 Alkyl, partially or fully fluorinated phenyl or fluorinated C 1-18 Alkoxy.

[0067] In some embodiments, the ring in Formula 2 is a benzyl ring.

[0068] In some embodiments, N is substituted at exactly one of C2, C3, or C4, and the ring in Formula 2 is a pyridinyl ring.

[0069] In some embodiments, at least one of R1 and R5 is H.

[0070] In some embodiments, when at least one of R1, R2, R3, R4, and R5 is an adjacent substituent to OH, it is H.

[0071] In some embodiments, no more than one of R1, R2, R3, R4, and R5 is X.

[0072] In some embodiments, no more than 2 of R1, R2, R3, R4, and R5 are halogen.

[0073] In some embodiments, only one of R2, R3, and R4 is OH.

[0074] In some embodiments, R2 or R4 is OH.

[0075] In some embodiments, R1 and R5 are selected from the group consisting of: H, fluorine, C which may be partially or fully fluorinated. 1-18 Alkyl, partially or fully fluorinated C 1-18Alkoxy and X; and R2, R3 and R4 are independently selected from the group consisting of: OH, H, fluorine, C which may be partially or fully fluorinated 1-18 Alkyl, partially or fully fluorinated C 1-18 Alkoxy and X.

[0076] In some embodiments, one of R1, R2, R3, R4, and R5 is X and X is Formula 2.

[0077] In some embodiments, R6, R7, R8, R9 and R 10 independently selected from the group consisting of: H, fluorine, C which may be partially or fully fluorinated 1-6 Alkyl and partially or fully fluorinated C 1-6 Alkoxy, and R6, R7, R8, R9 and R 10 At least one of them is fluorine, C which may be partially or completely fluorinated 1-6 Alkyl or partially or fully fluorinated C 1-6 Alkoxy.

[0078] In some embodiments, R6, R7, R8, R9 and R 10 are independently selected from the group consisting of: H, fluorine, perfluoromethyl and perfluoromethoxy, and R6, R7, R8, R9 and R 10 At least one of them is fluorine, perfluoromethyl or perfluoromethoxy.

[0079] In some embodiments, n is 0.

[0080] In some embodiments, -Y- is -O-.

[0081] In some embodiments, the curing agent is a fluorinated resorcinol analog. Exemplary fluorinated resorcinol analogs may include, but are not limited to:

[0082]

[0083]

[0084] In some embodiments, the curing agent is a fluorinated hydroquinone analog. Exemplary fluorinated hydroquinone analogs include, but are not limited to:

[0085]

[0086] In some embodiments, the curing agent is selected from the following structures:

[0087]

[0088] In some embodiments, the curing agent is part of a curable fluoroelastomer composition that also comprises a polyhydroxy curable fluoroelastomer and an acid acceptor.

[0089] In some embodiments, the curable fluoroelastomer composition comprises from about 0.1 parts by weight to about 10 parts by weight, alternatively from about 0.2 parts by weight to about 5 parts by weight, alternatively from about 0.5 parts by weight to about 5 parts by weight, alternatively from about 1 part by weight to about 2.4 parts by weight of a curing agent per 100 parts by weight of fluoroelastomer, or any value, range, or sub-range therebetween.

[0090] Fluoroelastomer can be any polyhydroxy curable fluoroelastomer. As used herein, "polyhydroxy curable" refers to a fluoroelastomer known to be crosslinked with a polyhydroxy curing agent such as BPAF. Such fluoroelastomers include, but are not limited to, those fluoroelastomers having multiple carbon-carbon double bonds along the main chain of the elastomeric polymer and also fluoroelastomers containing sites that can be easily dehydrogenated and fluorinated. The latter fluoroelastomers include, but are not limited to, those fluoroelastomers containing adjacent copolymerized units of vinylidene fluoride (VF2) and hexafluoropropylene (HFP), and fluoroelastomers containing adjacent copolymerized units of VF2 (or tetrafluoroethylene) and fluorinated comonomers having acidic hydrogen atoms, such as 2-hydropentafluoropropylene; 1-hydropentafluoropropylene; trifluoroethylene; 2,3,3,3-tetrafluoropropylene; or 3,3,3-trifluoropropylene. Preferred fluoroelastomers include copolymers of i) vinylidene fluoride with hexafluoropropylene and optionally tetrafluoroethylene (TFE); ii) vinylidene fluoride with perfluoro(alkyl vinyl ether) such as perfluoro(methyl vinyl ether), 2-hydropentafluoropropylene and optionally tetrafluoroethylene; iii) tetrafluoroethylene with propylene and 3,3,3-trifluoropropylene; iv) tetrafluoroethylene, perfluoro(methyl vinyl ether) and hexafluoro-2-(pentafluorophenoxy)-1-(trifluoroethyleneoxy)propane, and v) ethylene with tetrafluoroethylene, perfluoro(methyl vinyl ether) and 3,3,3-trifluoropropylene. In some embodiments, the polyhydroxy-curable fluoroelastomer is a dimer of hexafluoropropylene and vinylidene fluoride. The polyhydroxy-curable fluoroelastomer may also include an iodine-containing elastomer, a bromine-containing elastomer or a chlorine-containing elastomer. For example, small amounts (0.01 wt % to 1 wt %) of chlorine, bromine or iodine may be introduced with a telogen such as CH2I2 or I(CF2)4I or a monomer such as CH2=CHCF2CF2X (X=Br, I) or chlorotrifluoroethylene. In some embodiments, the polyhydroxy curable fluoroelastomer contains a diene such as CH2=CH(CF2) n CH=CH2 (where n=2-8) or CF2=CFO(CF2) n OCF=CF2 (where n=2-8).

[0091] Suitable acid acceptors may include, but are not limited to, powdered magnesium oxide, calcium hydroxide, zinc oxide, bismuth oxide, lead oxide, calcium oxide, hydrotalcite, barium carbonate, calcium carbonate, alkyl stearates, or combinations thereof. In some embodiments, the curable fluoroelastomer composition comprises about 3 parts by weight to about 15 parts by weight, alternatively about 5 parts by weight to about 15 parts by weight, alternatively about 6 parts by weight to about 12 parts by weight, alternatively about 8 parts by weight to about 10 parts by weight, or any value, range, or sub-range therebetween of an acid acceptor per 100 parts by weight of the fluoroelastomer. In some embodiments, the composition comprises two or more acid acceptors.

[0092] In some embodiments, the curable composition comprises an organic base. Suitable organic bases may include, but are not limited to, 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU) or a salt thereof, 1,5-diazabicyclo(4.3.0)-non-5-ene (DBN) or a salt thereof, or a combination thereof.

[0093] In some embodiments, the curable composition further comprises one or more additives. Suitable additives may include, but are not limited to, processing aids and / or colorants.

[0094] In some embodiments, the fluoroelastomer masterbatch comprises a curing agent and a polyhydroxy curable fluoropolymer.

[0095] In some embodiments, the curing agent and curing accelerator mixture includes a curing agent and a curing accelerator.

[0096] Suitable curing accelerators may include, but are not limited to, tertiary sulfonium salts such as [(C6H5)2S + (C6H 13 )][Cl] - and [(C6H 13 )2S(C6H5)] + [CH3CO2] - And R5R6R7R8Y + X - A quaternary ammonium salt, phosphonium salt, arsenonium salt or antimononium salt, wherein Y is phosphorus, nitrogen, arsenic or antimony; R5, R6, R7 and R8 are independently C1-C 20 Alkyl, aryl, aralkyl, alkenyl and their chlorine, fluorine, bromine, cyano, -OR and -COOR substituted analogs, wherein R is C1-C 20 alkyl, aryl, aralkyl, alkenyl, and wherein X is halide, hydroxide, sulfate, sulfite, carbonate, pentachlorothiophenol, tetrafluoroborate, hexafluorosilicate, hexafluorophosphate, dimethyl phosphate, and C1-C 20Alkyl, aryl, aralkyl and alkenyl carboxylates and dicarboxylates. Particularly preferred are benzyltriphenylphosphonium chloride, benzyltriphenylphosphonium bromide, tetrabutylammonium hydrogensulfate, tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium bromide, tributylallylphosphonium chloride, tributyl-2-methoxypropylphosphonium chloride, 1,8-diazabicyclo[5.4.0]undec-7-ene and benzyldiphenyl(dimethylamino)phosphonium chloride. Other suitable curing accelerators include methyl trioctylammonium chloride, methyl tributylammonium chloride, tetrapropylammonium chloride, benzyl trioctylphosphonium bromide, benzyl trioctylphosphonium chloride, methyl trioctylphosphonium acetate, tetraoctylphosphonium bromide, methyl triphenylarsenic tetrafluoroborate, tetraphenylantimonium bromide, 4-chlorobenzyltriphenylphosphonium chloride, 8-benzyl-1,8-diazabicyclo(5.4.0)-7-undecenium chloride, diphenylmethyltriphenylphosphonium chloride, allyltriphenylphosphonium chloride, tetrabutylphosphonium bromide, m-trifluoromethyl-benzyltrioctylphosphonium chloride, and other quaternary compounds disclosed in U.S. Pat. Nos. 5,591,804, 4,912,171, 4,882,390, 4,259,463, 4,250,278, and 3,876,654.

[0097] In some embodiments, the curing accelerator includes a quaternary phosphonium salt, a quaternary ammonium salt, or a tertiary sulfonium salt.

[0098] In some embodiments, the cure accelerator includes benzyltriphenylphosphonium chloride or tetrabutylammonium hydrogen sulfate.

[0099] In some embodiments, the weight ratio of the curing agent and the curing accelerator in the curing agent and curing accelerator mixture is in the range of about 1:1 to about 12:1, alternatively about 1.5:1 to about 10:1, alternatively about 2:1 to about 8:1, or any value, range or sub-range therebetween.

[0100] In some embodiments, the curing agent and the curing accelerator are pre-reacted to form a salt of the curing agent and the curing accelerator. In some embodiments, the curing agent is in two to six times molar excess, alternatively in two to five times molar excess, alternatively in three to six times molar excess, alternatively in about 3.5 times molar excess, alternatively in about 5.3 times molar excess, or any value, range or sub-range therebetween, relative to the amount of the curing accelerator.

[0101] In some embodiments, the pre-reacted curing agent-curing accelerator salt provides similar curing properties but significantly better compression set for the cured polymer compared to the same curing agent and curing accelerator not in the pre-reacted salt. In some embodiments, the compression set is reduced by at least 10% with the pre-reacted salt. In some embodiments, the compression set is reduced by at least 30% with the pre-reacted salt. In some embodiments, the compression set is reduced by a greater percentage than when BPAF is used as the curing agent.

[0102] In some embodiments, the phenoxide salt derived from the curing agent of Formula 1 is in the form of a quaternary phosphonium salt or a quaternary ammonium salt and is used as a curing agent and a curing accelerator for fluoroelastomers.

[0103] In some embodiments, a method cures a polyhydroxy-curable fluoropolymer with a curing agent.

[0104] In some embodiments, the method includes forming a mixture of a polyhydroxy curable fluoropolymer, a curing agent, at least one acid acceptor, and a cure accelerator.

[0105] In some embodiments, the mixture comprises from about 0.05 parts by weight to about 1.5 parts by weight, alternatively from about 0.1 parts by weight to about 1 parts by weight, alternatively from about 0.2 parts by weight to about 0.8 parts by weight, alternatively from about 0.25 parts by weight to about 0.6 parts by weight, or any value, range, or sub-range therebetween, of a cure accelerator per 100 parts by weight of fluoroelastomer.

[0106] In some embodiments, the mixture also includes filler. The filler may include one or more inorganic fillers, one or more polymer fillers or a combination thereof. In some embodiments, the filler is medium-heat carbon black. Other suitable inorganic fillers may include but are not limited to silicon dioxide, talc, titanium dioxide (TiO2), barium sulfate (BaSO4), calcium carbonate (CaCO3) or a combination thereof. Suitable polymer fillers may include but are not limited to polytetrafluoroethylene (PTFE). In some embodiments, the mixture includes about 10 parts by weight of fluoroelastomer per 100 parts by weight to about 40 parts by weight, alternatively about 20 parts by weight to about 40 parts by weight, alternatively about 25 parts by weight to about 35 parts by weight, alternatively about 30 parts by weight, or any value, range or sub-range filler therebetween.

[0107] In some embodiments, the curing temperature ranges from about 150°C to about 200°C, alternatively from about 160°C to about 190°C, alternatively from about 170°C to about 180°C, or any value, range, or sub-range therebetween.

[0108] In some embodiments, the curing time ranges from about 5 minutes to about 60 minutes, alternatively from about 5 minutes to about 20 minutes, alternatively from about 10 minutes to about 30 minutes, alternatively from about 20 minutes to about 30 minutes, or any value, range, or sub-range therebetween.

[0109] In some embodiments, the curing agent provides curing properties similar to those of BPAF. Such properties may include, but are not limited to, L 、M H ,ts1,ts2,t 50and t 90 In some embodiments, the value is within 50%, alternatively within 40%, alternatively within 30%, alternatively within 20%, alternatively within 10%, alternatively within 5%, or any value, range, or sub-range therebetween, of the value of BPAF as a curing agent.

[0110] In some embodiments, the curing agent provides a cured fluoroelastomer having properties similar to those of a cured fluoroelastomer formed using BPAF as the curing agent. Such properties may include, but are not limited to, resistance to compression set, tensile strength, elongation at break, and 100% elastic modulus. In some embodiments, the value is within 50%, alternatively within 40%, alternatively within 30%, alternatively within 20%, alternatively within 10%, alternatively within 5%, or any value, range, or sub-range therebetween of the value of BPAF as the curing agent.

[0111] In some embodiments, a method of curing a polyhydroxy curable fluoroelastomer comprises forming a curable fluoroelastomer composition comprising a polyhydroxy curable fluoroelastomer, a curing agent of Formula 1, and an acid acceptor, and heating the curable fluoroelastomer composition to cure the polyhydroxy curable fluoroelastomer.

[0112] In some embodiments, the curable fluoroelastomer composition is free or substantially free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

[0113] In some embodiments, the article is cured by the curing method.

[0114] In some embodiments, the article is free or substantially free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

[0115] In another embodiment, the compound has Formula 1A:

[0116]

[0117] wherein one of R1 and R2 is H and the other is OH. One of R3 and R4 is H and the other is selected from the group consisting of Formula 2A and Formula 3A:

[0118]

[0119] wherein R5, R6, R7, R8 and R9 are independently selected from the group consisting of: H, F, CF3, partially or fully fluorinated phenyl, OCF3, CH3, nitro and nitrile; provided that at least one of R5, R6, R7, R8 and R9 is selected from the group consisting of: F, CF3, partially or fully fluorinated phenyl and OCF3; provided that when R5, R6, R7, R8 and R9 are independently selected from the group consisting of H and F, at least two are H and at least two are F; provided that when R1 is OH, R3 is Formula 2A, and R5, R6, R7, R8 and R9 are independently selected from the group consisting of H and CF3, at least one of R6 and R8 is H; and provided that N may be substituted at exactly one of C2, C3 or C4, in which case the corresponding R5, R6 or R7 is not present.

[0120] Applications of the cured fluoropolymers described herein may include, but are not limited to, sealing materials, shaft seals, O-rings, containers, hoses, or wearable applications such as watch bands.

[0121] In some embodiments, the fluoroelastomer is blended with one or more other fluoroelastomers or polymers to form a polymer blend. Suitable blending polymers include, but are not limited to, nylon or other polyamides.

[0122] Although curing agents for curing curable fluoroelastomers have been described herein, these curing agents may have other applications as well. In some embodiments, the curing agent reacts with a polyisocyanate to form a polyurethane.

[0123] In other embodiments, the curing agent is contained in the polyester. In some such embodiments, the curing agent is condensed with an aliphatic dicarboxylic acid or an aromatic dicarboxylic acid (e.g., terephthalic acid, isophthalic acid, or mixtures thereof or esters thereof) to form an aliphatic-aromatic polyester or an aromatic-aromatic polyester, respectively. The resulting polymer may be amorphous, high T g Materials or liquid crystal aromatic polyesters. The introduction of fluorinated aromatic side groups can result in good polymer processability, good thermal stability and / or good oxidative stability.

[0124] In other embodiments, the curing agent is contained in a polyimide, polyamide, polycarbonate, and / or epoxy resin.

[0125] Test Method

[0126] Moving Die Rheometer (MDR) Measurements

[0127] The curing properties of about 8 grams of the fluoroelastomer cured composition were measured on an MDR-2000 rheometer (Alpha Technologies, Bellingham, WA) according to ASTM D5289. The curing temperature was 177° C. and the curing time was 24 minutes. The moving die frequency was 1.66 Hz and the amplitude was 0.5°.

[0128] The reported cured properties include M in dN·m L , M in dN·m H , ts1 in minutes, ts2 in minutes, t in minutes 50 and t in minutes 90 .

[0129] Fluoroelastomer Performance Measurement

[0130] Compression set resistance of fluoroelastomers is determined according to ASTM D395, Test Method B, using a compression apparatus that compresses the fluoroelastomer sample to 25% deflection. Prior to compression set testing, the fluoroelastomer was post-cured at 232°C for 16 hours. Compression set resistance is reported as the percentage change in thickness after a predetermined time at a predetermined temperature. Three values ​​are reported herein: 70 hours at 200°C (CS1), 168 hours at 200°C (CS2), and 70 hours at 250°C (CS3).

[0131] The tensile properties of the unaged fluoroelastomers were determined by the ISO 37:2005C or 1 2008 test protocol at 23°C. The fluoroelastomers were post-cured at 232°C for 16 hours prior to tensile testing. The tensile properties measured included tensile strength in MPa, elongation at break in %, and 100% elastic modulus in MPa.

[0132] Certain fluoroelastomer O-rings were fluid aged by placing them in sulfuric acid at 70°C for 168 hours. Prior to fluid aging, the fluoroelastomers were post-cured at 232°C for 16 hours. After fluid aging, the swelling of the fluoroelastomers was measured in weight percent and the samples were tested for compression set (CS1).

[0133] Example

[0134] Synthesis Example

[0135] 29 fluorinated resorcinol or hydroquinone analogs were prepared and evaluated as curing agents. The chemical structures of these inventive examples (IE) are shown in Table 1.

[0136] The raw material of Inventive Example 1 was obtained from MilliporeSigma (Burlington, MA) and further purified by silica gel column chromatography.

[0137] The fluorinated resorcinol analogs of Inventive Examples 2-12 and 15-19, 21-27 and 29 and the fluorinated hydroquinone analog of Inventive Example 20 were prepared by a palladium catalyst-based synthesis method commonly used for coupling arylboronic acids with arylbromides as building blocks. When the aromatic hydroxyl group of the building block was protected by a methyl group, an additional hydrolysis step of the methoxy group was used to prepare the fluorinated resorcinol and hydroquinone analogs.

[0138] For example, in the synthesis of Inventive Example 2, 3,5-dimethoxy-phenylboronic acid (12.5 g), 1-bromo-2,3,5-trifluorobenzene (11 g), potassium carbonate (13.8 g), Pd(PPh3)4 (0.36 g), water (44 g) and toluene (132 g) were stirred and refluxed for 4 hours under nitrogen. The resulting toluene solution was separated and dried over MgSO4. Toluene was distilled off and the resulting (MeO)2C6H3-C6F3H2 was distilled under vacuum (120°C-142°C / 0.6 Torr-0.8 Torr). Then, (MeO)2C6H3-C6F3H2 (6.3 g) was diluted in dichloromethane (22 g), and a solution of 1M BBr3 in dichloromethane (52 mL) was added at a temperature of -7°C to 0°C, and it was stirred and warmed to room temperature overnight. The mixture was then cooled to 0°C; water was carefully added dropwise; and the product was extracted with ethyl acetate. The extract was dried and filtered, and the solvent was evaporated to obtain the final yellow powder of Inventive Example 2 (4.4 g, melting point = 187°C, 3,5-(HO)2C6H3-C6F3H2).

[0139] Table 1: Chemical formula of the invention examples

[0140]

[0141] Table 1: Chemical formula of the invention examples (continued)

[0142]

[0143] For Inventive Example 12, 3,5-difluoro-phenylboronic acid (16.08 g), 1-bromo-3,5-dimethoxy-benzene (17 g), potassium carbonate (19.5 g), Pd(PPh3)4 (0.45 g), water (68 g) and toluene (206 g) were stirred and refluxed under nitrogen for 4 hours. The resulting toluene solution was separated and dried over MgSO4. Toluene was distilled off, and the resulting (MeO)2C6H3-C6F2H3 was distilled under vacuum (141°C-145°C / 1.3 Torr). The obtained (MeO)2C6H3-C6F2H3 (11.8 g) was reacted with 48% hydrobromic acid (39 g) and acetic acid (34.6 g) at 114°C for 20 hours. Most of the acid was removed by vacuum distillation, and the distillation residue was neutralized with 6.9 g of a 25% NaOH aqueous solution, extracted with ethyl acetate and dried over MgSO4. The ethyl acetate was distilled off and the resulting 3,5-(HO)2C6H3-C6F2H3 was recrystallized to obtain the final off-white solid of Inventive Example 12 (7.55 g, melting point = 144°C).

[0144] For Inventive Example 13, potassium carbonate (17.7 g), N,N-dimethylformamide (DMF, 65.56 g) and pentafluorobenzene (10.6 g) were loaded into a 250 mL reactor and preheated to 80 ° C. A mixture of 3,5-dimethoxyphenol (9.8 g) and DMF (11.9 g) was added from a dropping funnel within 20 minutes. The mixture was stirred and heated to 90 ° C for 8 hours. Then, 1.9 g of pentafluorobenzene was added and continued to heat for 9 hours to achieve a 98% conversion rate of 3,5-dimethoxyphenol measured by GC / MS. Water (150 g) was added, and the crude 3,5-dimethoxyphenyl 2,3,5,6-tetrafluorophenyl ether as a solid was filtered and purified by vacuum distillation at 102 ° C-118 ° C / 0.6 torr-0.8 torr. Then 3,5-dimethoxyphenyl 2,3,5,6-tetrafluorophenyl ether (MeO) 2C6H3-O-C6F4H (12.9 g) was diluted in dichloromethane (68 g), and 1M BBr3 solution in dichloromethane (60 mL) was added at -14°C to -3°C within 15 minutes, and stirred and slowly warmed to room temperature overnight. The mixture was cooled with an ice-water bath, and water was carefully added dropwise. The product was extracted with ethyl acetate. The extract was dried and filtered, and the solvent was evaporated to obtain the final yellow powder of Inventive Example 13 (11 g, melting point = 142°C).

[0145] For Inventive Example 14, 85 g (0.34 mol) of boron tribromide was added dropwise to a vigorously stirred solution of 25 g (0.16 mol) of 3,5-dimethoxy-1-fluorobenzene in 200 mL of dichloromethane at 0°C-3°C (ice-water cooling bath). The reaction mixture was stirred continuously while warming to room temperature, and then the mixture was stirred at room temperature overnight. The reaction mixture was then cooled with ice water and quenched with deionized water. The solvent was removed with a rotary evaporator, and the crude product was extracted from the mixture with ether. The crude product was purified by passing through a silica gel column. The synthesis was repeated using the same loading of raw materials, and the products from the two batches were combined. The combined material was recrystallized from toluene and dried to remove the residual solvent to obtain 27.5 g (an average of 67% for two batches) of Inventive Example 14.

[0146] For Inventive Example 28, a solution of 3,5-dimethoxy-phenylmagnesium bromide in 2-methyltetrahydrofuran (32 mL, 0.71 mol) was added to a flask containing pentafluoropyridine (9.5 g, 0.56 mol) at 10° C. over 5 minutes. After reacting at room temperature for 40 minutes, the reaction was heated to 52° C. for 24 hours. The reaction was then quenched with water, washed, and dried over MgSO4. The solvent was removed under vacuum on a rotary evaporator to obtain the crude adduct (13.1 g), which was prepared according to 1 H and 19 F NMR, the crude adduct contained 4-(3,5-dimethoxyphenyl)-2,3,5,6-tetrafluoropyridine and 2-(3,5-dimethoxyphenyl)-3,4,5,6-tetrafluoropyridine (ratio 64.5:35.5 as determined by GC / MS). After recrystallization twice from toluene, a white crystalline solid containing 4-(3,5-dimethoxyphenyl)-2,3,5,6-tetrafluoropyridine and 2-(3,5-dimethoxyphenyl)-3,4,5,6-tetrafluoropyridine was obtained (ratio 64.5:35.5 as determined by GC / MS and 19 F NMR determination was 99:1). 5.6 g of the recrystallized product was reacted with 48% hydrobromic acid (19 g) and acetic acid (27 g) at 114°C-116°C for 12 hours. After complete conversion was confirmed by GC / MS, most of the excess acid was removed by vacuum distillation, and the distillation residue was diluted with ethyl acetate and neutralized with 6.4 g of 25% aqueous NaOH. The organic layer was washed with water and dried over MgSO4. The ethyl acetate was removed by rotary evaporation and vacuum drying to obtain 4.6 g (mp=214°C-218°C) of Inventive Example 28 (5-(2,3,5,6-tetrafluoropyridin-4-yl)benzene-1,3-diol) as a white solid.

[0147] The melting points of the inventive examples, except IE20, were determined and are given in Table 2.

[0148] Table 2: Melting points of inventive examples

[0149]

[0150] Comparative Fluoroelastomer Curing Example

[0151] Since the conditions for each set of curing runs were slightly different, 2,2-bis(4-hydroxyphenyl)hexafluoropropane (BPAF) (Comparative Example AP) was used as the curing agent to compare each set of curing runs of the curing agent invention examples.

[0152] The comparative fluoroelastomer curing composition comprises 100 parts by weight of Viton as a polyhydroxy curable fluoroelastomer. TM A-500 (Chemours Company FC LLC, Wilmington, DE), 30 parts by weight of medium thermal black (MT Black) as a filler, 3 parts by weight of powdered MgO ( 170, Akrochem Corporation, Akron, OH), 6 parts by weight of calcium hydroxide (Hallstar International, Chicago, IL) as an acid acceptor, 2 parts by weight of BPAF, and 0.55 parts by weight of benzyltriphenol phosphonium chloride (BTPPC) as a curing accelerator. The only exception is Comparative Example B, which includes 3.3 parts by weight of powdered MgO instead of 3 parts by weight.

[0153] In another comparative example, 2,3,5,6-tetrafluorohydroquinone obtained from Synquest Laboratories, Inc. (Alachua, FL) was tested as a polyfluorinated hydroquinone curing agent having fluorine atoms at the R1, R2, R4, and R5 positions. The curing reaction was very slow, reaching only very low M of 3.77 dN·m and 5.36 dN·m. H values, which is too low a cure state for molding and measuring physical properties.

[0154] Fluoroelastomer curing embodiment of the present invention

[0155] The prepared fluorinated resorcinol and hydroquinone analogs were evaluated as curing agents in curing compositions (Inventive Examples 1-29).

[0156] The fluorine-containing elastomer curing composition of the present invention comprises 100 parts by weight of Viton as a polyhydroxy curable fluorine-containing elastomer. TMA-500, 30 parts by weight of MT Black as a filler, 3 parts by weight of powdered MgO as an acid acceptor, 6 parts by weight of calcium hydroxide as an acid acceptor, 1.02 to 2.42 parts by weight of a curing agent, and 0.25 to 0.60 parts by weight of BTPPC as a curing accelerator. The amounts of curing agent and BTPPC in each curing composition are shown in Table 3. For Inventive Example 20, the curing agent was provided in the form of 10% by weight on MT Black, with a total amount of 19.33 parts by weight.

[0157] Table 3: Fluoroelastomer Curing Composition

[0158]

[0159] In some cases, several runs were performed using the same curative, with the amounts of curative and BTPPC adjusted based on previous results to obtain cure properties and / or fluoroelastomer properties more similar to those using BPAF as the curative.

[0160] Fluoroelastomer Curing Results

[0161] The cure performance of the inventive examples of Table 1 in the cured compositions of Table 3 and the cure performance of their corresponding comparative examples are shown in Tables 4-7. Each comparative example is listed directly before the inventive example from the same set of MDR runs. When multiple runs were performed using the same curing agent, only the run with the best combination of cure and fluoroelastomer properties was selected for inclusion in the table.

[0162] Table 4: Curing properties

[0163] (Comparative Examples AE and Inventive Examples 1-6)

[0164] Example A 1 B 2 C 3 D 4 E 5 6 <![CDATA[M L (dN·m)]]> 1.27 1.59 1.27 1.12 1.28 1.00 1.28 1.03 0.90 0.87 0.76 <![CDATA[M H (dN·m)]]> 25.87 24.89 24.61 26.30 24.10 25.81 23.66 22.04 24.18 25.11 24.69 ts1(minutes) 1.35 1.30 1.35 1.46 1.45 1.25 1.33 1.18 1.07 0.97 1.07 ts2(minutes) 1.55 1.71 1.53 1.69 1.66 1.43 1.52 1.45 1.20 1.09 1.23 <![CDATA[t 50 (minutes)]]> 1.97 3.48 1.95 2.34 2.14 2.02 1.91 2.53 1.51 1.42 1.77 <![CDATA[t 90 (minutes)]]> 3.18 6.61 2.70 3.14 3.07 2.93 2.60 3.69 2.21 1.92 2.44

[0165] Table 5: Curing properties

[0166] (Comparative Examples FH and Inventive Examples 7-14)

[0167] Example F 7 8 9 G 10 11 12 H 13 14 <![CDATA[M L (dN·m)]]> 0.93 0.89 0.91 0.90 0.99 0.85 0.71 0.87 0.95 0.82 1.04 <![CDATA[M H (dN·m)]]> 23.39 21.05 24.78 24.99 24.58 24.20 23.63 24.99 24.02 23.96 23.11 ts1(minutes) 1.14 0.99 0.98 1.03 1.03 1.04 1.07 1.06 1.09 1.08 0.97 ts2(minutes) 1.27 1.16 1.11 1.18 1.15 1.19 1.25 1.19 1.22 1.26 1.15 <![CDATA[t 50 (minutes)]]> 1.58 1.68 1.46 1.59 1.46 1.64 1.81 1.55 1.53 1.85 1.77 <![CDATA[t 90 (minutes)]]> 2.21 2.41 2.03 2.24 2.15 2.28 2.70 2.14 2.20 2.68 2.68

[0168] Table 6: Curing properties

[0169] (Comparative Example 1L and Inventive Examples 15-22)

[0170] Example I 15 J 16 17 K 18 19 20 L 21 22 <![CDATA[M L (dN·m)]]> 0.91 0.77 0.96 0.72 0.57 0.93 0.91 0.92 1.17 0.91 0.83 0.65 <![CDATA[M H (dN·m)]]> 23.63 20.66 24.59 24.20 22.54 23.63 24.65 19.73 20.30 23.84 25.14 22.29 ts1(minutes) 1.08 0.95 1.24 1.02 1.01 1.16 1.56 1.32 0.54 1.13 0.89 1.03 ts2(minutes) 1.20 1.10 1.41 1.17 1.16 1.29 1.90 1.58 0.63 1.27 1.01 1.22 <![CDATA[t 50 (minutes)]]> 1.48 1.55 1.79 1.63 1.60 1.62 2.58 2.26 1.10 1.58 1.40 2.09 <![CDATA[t 90 (minutes)]]> 2.06 2.27 2.62 2.32 2.40 2.34 3.64 3.34 2.25 2.20 1.91 3.28

[0171] Table 7: Curing properties

[0172] (Comparative Example MP and Inventive Examples 23-29)

[0173] Example M 23 24 N 25 O 26 27 28 P 29 <![CDATA[M L (dN·m)]]> 0.83 0.75 0.84 1.05 1.02 1.17 1.16 1.35 1.03 1.18 1.18 <![CDATA[M H (dN·m)]]> 23.13 23.25 23.89 24.44 21.86 26.10 25.57 23.05 26.09 26.61 25.11 ts1(minutes) 1.10 1.01 0.99 1.28 1.25 1.23 1.06 1.48 0.97 1.16 1.03 ts2(minutes) 1.24 1.19 1.16 1.48 1.56 1.39 1.22 1.79 1.12 1.31 1.20 <![CDATA[t 50 (minutes)]]> 1.57 1.77 1.64 1.94 2.41 1.76 1.80 2.60 1.63 1.66 1.79 <![CDATA[t 90 (minutes)]]> 2.52 2.99 2.58 3.16 3.95 2.70 2.95 3.99 2.46 2.42 2.65

[0174] Tables 4-7 show that the inventive examples provide curing properties similar to those of BPAF. Tables 4-7 show that for the inventive examples, M L The value is in the range of 0.57dN·m to 1.59dN·m, M H The values ​​are in the range of 19.73 dN·m to 26.3 dN·m, the ts1 values ​​are in the range of 0.54 min to 1.56 min, the ts2 values ​​are in the range of 0.63 min to 1.90 min, and the t 50 The values ​​range from 1.10 minutes to 3.48 minutes, and t 90 The values ​​ranged from 1.91 minutes to 6.61 minutes.

[0175] Fluoroelastomer Properties

[0176] The fluoroelastomer properties of the fluoroelastomers formed from the inventive examples of Table 1 and the fluoroelastomer properties of the fluoroelastomers formed from their corresponding comparative examples in the cured compositions of Table 3 are shown in Tables 8 - 11. When multiple runs were performed using the same curative, only the run with the best combination of cure and fluoroelastomer properties was selected for inclusion in the table.

[0177] Table 8: Fluoroelastomer properties

[0178] (Comparative Examples AE and Inventive Examples 1-6)

[0179] Example A 1 B 2 C 3 D 4 E 5 6 TS[MPa] 15.7 15.5 16.1 15.0 15.2 15.4 14.5 15.2 13.7 15.7 15.6 EB[%] 212 174 206 168 213 181 212 204 181 187 149 M100[MPa] 6.7 7.5 6.6 7.4 6.2 7.3 6.0 5.6 6.3 7.0 8.7 cS1(%) 19.1 16.9 21.3 19.1 18.0 18.2 20.2 15.7 18.6 25.6 18.6 CS2 (%) 30.3 23.6 33.7 29.2 30.7 32.6 30.7 25.8 31.4 34.5 29.1 CS3 (%) N / D N / D N / D N / D N / D N / D N / D N / D 66.3 68.6 59.3

[0180] Table 9: Fluoroelastomer properties

[0181] (Comparative Examples FH and Inventive Examples 7-14)

[0182] Example F 7 8 9 G 10 11 12 H 13 14 TS[MPa] 15.3 15.2 15.7 14.3 13.4 15.4 13.5 15.0 12.8 15.1 16.5 EB[%] 207 212 190 167 186 183 182 187 176 172 170 M100[MPa] 5.9 5.3 6.8 7.3 6.1 6.9 6.3 6.8 3.0 3.1 3.3 CS1(%) 18.4 19.5 20.9 20.9 18.4 19.8 20.7 20.7 19.8 20.9 19.8 CS2 (%) 30.2 31.0 31.4 32.6 27.9 27.9 30.2 31.8 27.6 34.9 32.6 CS3 (%) 60.5 58.6 62.8 65.5 62.4 59.3 62.8 63.2 59.3 62.8 80.2

[0183] Table 10: Fluoroelastomer properties

[0184] (Comparative Example 1L and Inventive Examples 15-22)

[0185] Example I 15 J 16 17 K 18 19 20 L 21 22 TS[MPa] 14.1 14.2 15.7 15.8 16.1 14.8 13.8 16.0 17.1 15.2 17.1 13.3 EB[%] 202 188 205 190 160 197 180 215 215 197 185 135 M100[MPa][ 5.9 5.6 6.1 6.4 8.0 6.2 7.2 5.5 5.6 6.3 7.6 8.1 CS1(%) 16.3 18.4 16.3 20.9 22.1 17.4 23.3 20.0 18.6 18.6 19.8 25.6 CS2 (%) 28.7 31 25.6 31.4 33.7 27.9 36.5 28.4 32.6 30.2 31.0 40.7 CS3 (%) 60.9 60.9 60.5 65.1 68.6 62.8 71.6 62.4 73.3 62.8 63.2 75.6

[0186] Table 11: Fluoroelastomer properties

[0187] (Comparative Example MP and Inventive Examples 23-29)

[0188] Example M 23 24 N 25 O 26 27 28 P 29 TS[MPa] 13.9 15.8 15.2 13.5 13.2 14.0 14.6 15.2 14.1 14.5 13.7 EB[%] 212 200 208 227 195 182 170 195 144 190 170 M100[MPa] 5.1 6.0 5.9 5.2 5.7 6.5 7.3 6.4 8.0 6.9 7.1 CS1(%) 17.4 17.4 19.5 16.3 19.8 17.2 19.5 20.7 20.7 22.7 21.8 CS2 (%) 26.7 25.6 30.2 25.6 29.4 26.4 27.6 33.0 32.2 29.5 31.0 CS3 (%) 62.8 55.8 61.6 62.8 61.6 65.5 65.1 69.3 64.4 67.0 63.2

[0189] Tables 8-11 show that the inventive examples provide cured fluoroelastomers having properties similar to those of cured fluoroelastomers formed using BPAF as a curing agent. Tables 8-11 show that for the inventive examples, TS values ​​range from 13.2 MPa to 17.1 MPa, EB values ​​range from 135% to 215%, M100 values ​​range from 3.06 MPa to 8.69 MPa, CS1 values ​​range from 15.7% to 25.6%, CS2 values ​​range from 23.6% to 40.7%, and CS3 values ​​range from 55.8% to 80.2%.

[0190] Finally, the Inventive Example 1 fluid was aged and then tested. The swelling ratio of the fluid-aged fluoroelastomer formed with Inventive Example 1 as a curing agent was 3.5 wt % with a standard deviation of 0.2 wt %, and the CS1 of the fluid-aged fluoroelastomer formed with Inventive Example 1 as a curing agent was 22.0%. These results indicate that acid resistance is excellent for fluoroelastomers formed with fluorinated resorcinol and hydroquinone analogs as curing agents.

[0191] Curing Agent Salt Example

[0192] Formation of curing agent salt

[0193] To form the invention example of the curing agent salt, invention example 9 (IE9) was pre-reacted with BTPPC by the following procedure. IE9 (20.34 g, 0.0847 mol) and methanol (45 g) were charged into a 500 mL round bottom flask equipped with a magnetic stirring bar and a dropping funnel with a nitrogen tee on top. Then 25 wt % sodium methoxide in methanol (18.53 g, 0.0857 mol) was quickly added via an addition funnel and the solution was stirred at room temperature for 15 minutes. Next, a solution of BTPPC (33.0 g, 0.0849 mol) in methanol (17.9 g) was quickly added via an addition funnel. The mixture was stirred for 30 minutes while sodium chloride precipitated. The slurry was filtered through a polypropylene filter funnel with a 10 micron polyethylene frit to remove the sodium chloride, and then the slurry containing BTPP was added to the mixture. + IE9 - The filtrate of the salt was combined with a 3.5-fold molar excess of IE9 (71.34 g, 0.297 mol) dissolved in methanol (200 mL). Most of the methanol was removed by rotary evaporation, and residual methanol was then removed under vacuum at 150°C / 30 torr with magnetic stirring. While the mixture was still molten, a portion of the mixture was removed and rapidly cooled with liquid nitrogen and then dried under vacuum at room temperature for 18 hours. The solid (65.2 g) designated as IE9 / PRC1 was recovered and purified by filtration in MeOH-d4. 1H NMR determined to be 4.50:1 IE9:BTPP+ mol:mol. The remaining molten mixture was allowed to cool to room temperature and then dried in a vacuum oven at 80°C for 18 hours. The solid designated IE9 / PRC2 (53.0 g) was recovered and purified by centrifugation in MeOH-d4. 1 H NMR determined the molar ratio of IE9:BTPP+ to be 4.49:1. The total yield was 98.7%. BTPP + IE9 - The structure of the salt is shown in Formula 4.

[0194]

[0195] In a similar manner, BTPP was formed using a 3-fold molar excess of IE9. + IE9 - Salt. The product isolated by the rapid cooling method was named IE9 / PRC3 and was isolated by 1 H NMR determined to be 4.07:1 IE9:BTPP+ mol:mol.

[0196] In a similar manner, BTPP was formed using a 4-fold molar excess of IE9. + IE9 - Salt. The product isolated by the rapid cooling method was named IE9 / PRC4 and was isolated by 1 H NMR determined to be 5.08:1 IE9:BTPP+ mol:mol.

[0197] To form the curing agent salt of the invention example, a 3-fold molar excess of invention example 23 (IE23) was used by forming BTPP with IE9. + IE9 - IE23 was pre-reacted with BTPPC by the same procedure as the salt. While the product mixture was still molten, a portion of the mixture was taken out and rapidly cooled with liquid nitrogen and then dried under vacuum at room temperature for 18 hours. The solid (5.09 g) designated as IE23 / PRC1 was recovered and purified by distillation in MeOH-d4. 1 H NMR determined to be 4.05:1 I-23:BTPP+ mol:mol. The remaining molten mixture was allowed to cool to room temperature and then dried in a vacuum oven at 80°C for 18 hours. The solid designated IE23 / PRC2 (6.56 g) was recovered and purified by centrifugation in MeOH-d4. 1 H NMR determined to be 4.00:1 IE23:BTPP+ mol:mol. The overall yield was 100%.

[0198] For comparison, Viton available from Chemours was used. TMVC-50, a pre-reacted salt blend of BPAF and BTPP+.

[0199] Curing Examples Using Curing Agent Salts

[0200] The comparative fluoroelastomer curing composition and the fluoroelastomer curing composition of the present invention comprise 100 parts by weight of Viton as the polyhydroxy curable fluoroelastomer. TM B-600, 30 parts by weight of MT Black as a filler, 3 parts by weight of powdered MgO as an acid acceptor, 6 parts by weight of calcium hydroxide as an acid acceptor, and equimolar amounts of BPAF and IE9 (not pre-reacted with BTPPC or pre-reacted with BTPPC). Viton TM B-600 fluoroelastomer is a terpolymer of hexafluoropropylene, vinylidene fluoride and tetrafluoroethylene available from Chemours. The amount of pre-reacted salt is adjusted for the curing agent to cure to achieve t 90 Less than 3 minutes. For example, IE9 requires slightly less salt to complete. Curing was then compared at fixed levels of BPAF and IE9 or IE23. For example, for the cases of IE9 / PRC1 and IE9 / PRC2, because IE9 was cured with less BTPP+, an additional 0.35 phr IE9 was added to achieve an equimolar loading of IE9.

[0201] The curing properties of the curing compositions with unpre-reacted curing agents or pre-reacted curing agents are shown in Table 12. In the first set of MDR runs, the curing agents were BPAF (BPAF1), pre-reacted BPAF (BPAFS), IE9 (IE91), IE9 / PRC1 (9 / 1), and IE9 / PRC2 (9 / 2). In the second set of MDR runs, the curing agents were BPAF (BPAF2), IE9 (IE92), IE9 / PRC3 (9 / 3), and IE9 / PRC4 (9 / 4). In the third set of MDR runs, the curing agents were BPAF (BPAF3), IE23 (IE23), IE23 / PRC1 (23 / 1), and IE23 / PRC2 (23 / 2).

[0202] Table 12: Curing properties

[0203] Example BPAF1 BPAFS IE91 9 / 1 9 / 2 BPAF2 IE92 9 / 3 9 / 4 BPAF3 IE23 23 / 1 23 / 2 <![CDATA[M L (dN·m)]]> 1.08 0.94 0.81 0.87 0.90 1.14 1.06 1.14 1.17 1.38 1.31 1.33 1.41 <![CDATA[M H (dN·m)]]> 26.25 25.71 18.54 21.63 21.89 22.54 20.25 22.83 23.36 21.85 20.42 21.12 17.18 ts1(minutes) 1.01 1.49 0.83 1.00 1.02 1.21 1.01 1.06 1.09 2.28 1.52 1.49 2.21 ts2(minutes) 1.12 1.70 0.95 1.17 1.21 1.37 1.20 1.26 1.30 2.73 1.87 1.97 3.01 <![CDATA[t 50 (minutes)]]> 1.40 2.11 1.29 1.65 1.70 1.70 1.84 1.82 1.92 3.55 2.73 3.14 4.75 <![CDATA[t 90 (minutes)]]> 2.00 2.92 1.75 2.28 2.34 2.31 2.60 2.45 2.59 5.14 4.01 4.70 7.26

[0204] Table 12 shows that both the non-pre-reacted inventive examples and the pre-reacted inventive examples provide cure properties similar to that of BPAF.

[0205] Fluoroelastomer Properties

[0206] The fluoroelastomer properties of the fluoroelastomers whose cured properties are shown in Table 12 are shown in Table 13.

[0207] Table 13: Fluoroelastomer properties

[0208] Example BPAF1 BPAFS IE91 9 / 1 9 / 2 BPAF2 IE92 9 / 3 9 / 4 BPAF3 IE23 23 / 1 23 / 2 TS[MPa] 12.5 14.0 15.0 13.4 13.6 14.2 14.4 14.3 15.4 13.8 16.0 14.8 14.8 EB[%] 182 202 251 214 225 213 246 228 263 204 235 216 223 M100[MPa] 6.1 5.9 4.8 4.7 4.8 5.4 4.9 5.1 5.2 5.4 5.2 5.6 5.3 CS1(%) 25.3 19.8 39.5 24.1 25.3 25.3 34.5 21.8 21.6 25.3 27.3 23.0 25.3 ΔCS1 5.5 15.4 14.2 12.7 12.9 4.3 2.0 CS2 (%) 33.3 5.4 50.6 34.5 33.3 36.8 46.0 32.2 31.8 34.9 37.9 32.2 40.2 ΔCS2 16.1 17.3 13.8 14.2 5.7 -2.3 CS3 (%) 74.4 76.7 82.8 72.4 72.1 75.6 77.0 69.0 69.0 72.1 67.0 60.9 65.5 ΔCS3 -2.3 10.4 10.7 8.0 8.0 6.1 1.5

[0209] Table 13 shows that the fluoroelastomer properties of fluoroelastomers formed with IE9 / PRC1 and IE9 / PRC2 are essentially the same. For the fluoroelastomers formed in the first set of MDR runs, the pre-reacted curing agents of the present invention showed significantly greater improvements in CS1 (ΔCS1), CS2 (ΔCS1), and CS3 (ΔCS1) compared to BPAF relative to their non-pre-reacted equivalents. A positive ΔCS value indicates a reduction in CS. The CS improvement provided by the pre-reacted IE9 catalyst salt is surprisingly significantly greater than that of BPAF. In addition, the pre-reacted BPAF CS is actually worse at 250°C (CS3), while the pre-reacted IE9 CS improves by 10.4 points to 10.7 points.

[0210] The second set of MDR runs (where the IE9:BTPPC molar ratio was slightly lower or slightly higher than the first set of MDR runs) showed a similar trend with respect to the ΔCS values, but the improvement was not as great, but still significant.

[0211] For the third set of MDR runs, IE23 / PRC1 showed a significant but smaller improvement in ΔCS values ​​over IE9. Interestingly, the cure rate and compression set of IE23 / PRC1 were better than IE23 / PRC2, which did not show much improvement and was actually slightly worse at 168 hours (CS2) at 200°C. This demonstrates that in some cases it is advantageous to rapidly cool the molten eutectic catalyst mixture prior to rubber compounding and to dry and store at room temperature, rather than just slowly cooling to room temperature before drying at 80°C.

[0212] All of the above references are hereby incorporated by reference.

[0213] Although the present invention has been described with reference to preferred embodiments, it will be appreciated by those skilled in the art that various changes may be made and elements thereof may be replaced with equivalents without departing from the scope of the present invention. In addition, various modifications may be made to adapt specific circumstances or specific materials to the teachings of the present invention without departing from the essential scope of the present invention. Therefore, the present invention is not intended to be limited to the specific embodiments disclosed as the best intended mode for carrying out the present invention, but the present invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A curable fluorinated elastomer composition, comprising: Polyhydroxy curable fluoroelastomers; Curing agent of formula 1: wherein R1 and R5 are independently selected from the group consisting of: H, halogen, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy and X; wherein R2, R3 and R4 are independently selected from the group consisting of OH, H, halogen, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy and X, Provided that at least one of R2, R3 and R4 is OH; Provided that no more than 3 of R1, R2, R3, R4, and R5 are halogen; Wherein X is selected from the group consisting of Formula 2 and Formula 3: Among them, R6, R7, R8, R9 and R 10 independently selected from the group consisting of: H; C capable of being partially or fully halogenated 1-18 Alkyl; C can be partially or fully halogenated 1-18 alkoxy; partially or fully fluorinated phenyl, acetyl or methylsulfonyl which can be substituted by alkyl or aryl or partially or fully halogenated; nitro; nitrile; and halogen, provided that N can be substituted at exactly one of C2, C3 or C4, in which case the corresponding R6, R7 or R8 is absent; Where R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 independently selected from the group consisting of: H, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy, nitro, nitrile and halogen, provided that R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 One of them is -(Y) n - Single button to connect; wherein Y is selected from the group consisting of: -SO2-, -C(O)-, -C(CF3)2-, and -O-; and Where n is 0 or 1; The condition is that at least one of R1, R2, R3, R4 and R5 is fluorine, fluorine-containing C 1-18 Alkyl, fluorinated C 1-18 Alkoxy or X; Provided that when X exists and R1, R2, R3, R4 and R5 are not fluorine, fluorine-containing C 1-18 Alkyl or fluorinated C 1-18 In the case of alkoxy, R6, R7, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 At least one of them is fluorine, fluorine-containing C 1-18 Alkyl or fluorinated C 1-18 Alkoxy; and Acid receptors. 2 . The curable fluoroelastomer composition according to claim 1 , wherein at least one of R1 and R5 is H.

3. A curable fluoroelastomer composition according to claim 1 or 2, wherein when at least one of R1, R2, R3, R4 and R5 is an adjacent substituent of OH, it is H.

4. A curable fluoroelastomer composition according to any one of the preceding claims, wherein no more than one of R1, R2, R3, R4 and R5 is X.

5. A curable fluoroelastomer composition according to any one of the preceding claims wherein not more than 2 of R1, R2, R3, R4 and R5 are halogens.

6. A curable fluoroelastomer composition according to any one of the preceding claims, wherein only one of R2, R3 and R4 is OH.

7. The curable fluoroelastomer composition according to claim 6, wherein R2 or R4 is OH.

8. A curable fluoroelastomer composition according to any one of the preceding claims, wherein R1 and R5 are selected from the group consisting of: H, fluorine, C 1-18 Alkyl, partially or fully fluorinated C 1-18 Alkoxy and X; and wherein R2, R3 and R4 are independently selected from the group consisting of: OH, H, fluorine, C capable of partial or complete fluorination 1-18 Alkyl, partially or fully fluorinated C 1-18 Alkoxy and X.

9. The curable fluoroelastomer composition according to any one of the preceding claims, wherein one of R1, R2, R3, R4 and R5 is X, and X is of Formula 2.

10. The curable fluoroelastomer composition according to claim 9, wherein R6, R7, R8, R9 and R 10 independently selected from the group consisting of: H, fluorine, C 1-6 Alkyl and partially or fully fluorinated C 1-6 Alkoxy, and R6, R7, R8, R9 and R 10 At least one of the following is fluorine, partially or fully fluorinated C 1-6 Alkyl or partially or fully fluorinated C 1-6 Alkoxy.

11. The curable fluoroelastomer composition according to claim 9, wherein R6, R7, R8, R9 and R 10 are independently selected from the group consisting of: H, fluorine, perfluoromethyl and perfluoromethoxy, and R6, R7, R8, R9 and R 10 At least one of them is fluorine, perfluoromethyl or perfluoromethoxy.

12. A curable fluoroelastomer composition according to any one of the preceding claims wherein n is 0.

13. A curable fluoroelastomer composition according to any one of the preceding claims wherein -Y- is -O-.

14. The curable fluoroelastomer composition of claim 1, wherein the curing agent is selected from the group consisting of:

15. The curable fluoroelastomer composition according to any one of the preceding claims containing from about 0.1 to about 10 parts by weight of the curing agent per 100 parts by weight of fluoroelastomer.

16. A curable fluoroelastomer composition according to any one of the preceding claims wherein the polyhydroxy curable fluoroelastomer is a copolymer of hexafluoropropylene and vinylidene fluoride.

17. The curable fluoroelastomer composition according to any one of claims 1 to 15, wherein the polyhydroxy curable fluoroelastomer is a terpolymer of hexafluoropropylene, vinylidene fluoride and tetrafluoroethylene.

18. The curable fluoroelastomer composition according to any one of the preceding claims, wherein the acid acceptor is selected from the group consisting of powdered magnesium oxide, calcium hydroxide, and combinations thereof.

19. The curable fluoroelastomer composition according to any one of the preceding claims, wherein the curable fluoroelastomer composition is free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

20. The curable fluoroelastomer composition according to any one of the preceding claims further comprising a cure accelerator.

21. The curable fluoroelastomer composition of claim 20 wherein the cure accelerator is in the form of a salt pre-reacted with a portion of the curing agent.

22. The curable fluoroelastomer composition of claim 21 wherein the curing agent is present in a three to four fold molar excess of the cure accelerator.

23. A fluoroelastomer masterbatch comprising a polyhydroxy-curable fluoropolymer and a curing agent of Formula 1: wherein R1 and R5 are independently selected from the group consisting of: H, halogen, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy and X; wherein R2, R3 and R4 are independently selected from the group consisting of OH, H, halogen, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy and X, Provided that at least one of R2, R3 and R4 is OH; Provided that no more than 3 of R1, R2, R3, R4, and R5 are halogen; Wherein X is selected from the group consisting of Formula 2 and Formula 3: Among them, R6, R7, R8, R9 and R 10 Independently selected from the group consisting of: H; C that can be partially or fully halogenated 1-18 Alkyl; C can be partially or fully halogenated 1-18 alkoxy; partially or fully fluorinated phenyl, acetyl or methylsulfonyl which can be substituted by alkyl or aryl or partially or fully halogenated; nitro; nitrile; and halogen, provided that N can be substituted at exactly one of C2, C3 or C4, in which case the corresponding R6, R7 or R8 is absent; Where R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 independently selected from the group consisting of: H, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy, nitro, nitrile and halogen, provided that R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 One of them is -(Y) n - Single button to connect; wherein Y is selected from the group consisting of: -SO2-, -C(O)-, -C(CF3)2-, and -O, and wherein n is 0 or 1; The condition is that at least one of R1, R2, R3, R4 and R5 is fluorine, fluorine-containing C 1-18 Alkyl, fluorinated C 1-18 Alkoxy or X; Provided that when X exists and R1, R2, R3, R4 and R5 are not fluorine, fluorine-containing C 1-18 Alkyl or fluorinated C 1-18 In the case of alkoxy, R6, R7, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 At least one of them is fluorine, fluorine-containing C 1-18 Alkyl or fluorinated C 1-18 Alkoxy; The curing agent is present in a concentration of about 1 wt % to about 50 wt %.

24. The fluoroelastomer masterbatch of claim 23, wherein the concentration of the curing agent is from about 20 wt% to about 40 wt%.

25. A curing agent and curing accelerator mixture, the curing agent and curing accelerator mixture comprising a curing agent of Formula 1: wherein R1 and R5 are independently selected from the group consisting of: H, halogen, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy and X; wherein R2, R3 and R4 are independently selected from the group consisting of OH, H, halogen, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy and X, Provided that at least one of R2, R3 and R4 is OH; Provided that no more than 3 of R1, R2, R3, R4, and R5 are halogen; Wherein X is selected from the group consisting of Formula 2 and Formula 3: Among them, R6, R7, R8, R9 and R 10 independently selected from the group consisting of: H; C capable of being partially or fully halogenated 1-18 Alkyl; C can be partially or fully halogenated 1-18 alkoxy; partially or fully fluorinated phenyl, acetyl or methylsulfonyl which can be substituted by alkyl or aryl or partially or fully halogenated; nitro; nitrile; and halogen, provided that N can be substituted at exactly one of C2, C3 or C4, in which case the corresponding R6, R7 or R8 is absent; Where R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 independently selected from the group consisting of: H, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy, nitro, nitrile and halogen, provided that R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 One of them is -(Y) n - Single button to connect; wherein Y is selected from the group consisting of: -SO2-, -C(O)-, -C(CF3)2-, and -O, and wherein n is 0 or 1; The condition is that at least one of R1, R2, R3, R4 and R5 is fluorine, fluorine-containing C 1-18 Alkyl, fluorinated C 1-18 Alkoxy or X; Provided that when X exists and R1, R2, R3, R4 and R5 are not fluorine, fluorine-containing C 1-18 Alkyl or fluorinated C 1-18 In the case of alkoxy, R6, R7, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 At least one of them is fluorine, fluorine-containing C 1-18 Alkyl or fluorinated C 1-18 Alkoxy; and A curing accelerator selected from the group consisting of quaternary phosphonium salts, quaternary ammonium salts and tertiary sulfonium salts.

26. The curing agent and curing accelerator mixture according to claim 25, wherein the curing accelerator is a tertiary sulfonium salt.

27. The curing agent and curing accelerator mixture according to claim 25, wherein the curing accelerator is a quaternary ammonium salt.

28. The curing agent and curing accelerator mixture according to claim 27, wherein the quaternary ammonium salt is tetrabutylammonium hydrogen sulfate.

29. The curing agent and curing accelerator mixture of claim 25, wherein the curing accelerator is a quaternary phosphonium salt.

30. The curing agent and curing accelerator mixture of claim 29, wherein the quaternary phosphonium salt is benzyltriphenylphosphonium chloride.

31. The curing agent and curing accelerator mixture of claim 25, wherein the curing accelerator is in the form of a salt that is pre-reacted with a portion of the curing agent.

32. The curing agent and cure accelerator mixture of claim 31 , wherein the curing agent is present in a three-fold to four-fold molar excess of the cure accelerator.

33. A salt useful as a curing agent and curing accelerator for a fluoroelastomer, the salt comprising a quaternary phosphonium salt or a quaternary ammonium salt derived from a compound of formula 1: wherein R1 and R5 are independently selected from the group consisting of: H, halogen, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy and X; wherein R2, R3 and R4 are independently selected from the group consisting of OH, H, halogen, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy and X, Provided that at least one of R2, R3 and R4 is OH; Provided that no more than 3 of R1, R2, R3, R4, and R5 are halogen; Wherein X is selected from the group consisting of Formula 2 and Formula 3: Among them, R6, R7, R8, R9 and R 10 independently selected from the group consisting of: H; C capable of being partially or fully halogenated 1-18 Alkyl; C can be partially or fully halogenated 1-18 alkoxy; partially or fully fluorinated phenyl, acetyl or methylsulfonyl which can be substituted by alkyl or aryl or partially or fully halogenated; nitro; nitrile; and halogen, provided that N can be substituted at exactly one of C2, C3 or C4, in which case the corresponding R6, R7 or R8 is absent; Where R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 independently selected from the group consisting of: H, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy, nitro, nitrile and halogen, provided that R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 One of them is -(Y) n - Single button to connect; wherein Y is selected from the group consisting of: -SO2-, -C(O)-, -C(CF3)2-, and -O, and wherein n is 0 or 1; The condition is that at least one of R1, R2, R3, R4 and R5 is fluorine, fluorine-containing C 1-18 Alkyl, fluorinated C 1-18 alkoxy or X; and Provided that when X exists and R1, R2, R3, R4 and R5 are not fluorine, fluorine-containing C 1-18 Alkyl or fluorinated C 1-18 In the case of alkoxy, R6, R7, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 At least one of them is fluorine, fluorine-containing C 1-18 Alkyl or fluorinated C 1-18 Alkoxy.

34. The salt of claim 33, wherein the salt is a quaternary ammonium salt.

35. The salt according to claim 34, wherein the quaternary ammonium salt is tetrabutylammonium hydrogen sulfate.

36. The salt of claim 33, wherein the salt is a quaternary phosphonium salt.

37. The salt of claim 36, wherein the quaternary phosphonium salt is a benzyltriphenylphosphonium salt.

38. The salt of any one of claims 33 to 37, wherein the cure accelerator is in the form of a salt pre-reacted with a portion of the curing agent.

39. The salt of claim 38, wherein the curing agent is present in a three-fold to four-fold molar excess of the curing accelerator.

40. A method of curing a polyhydroxy-curable fluoroelastomer, the method comprising: A curable fluoroelastomer composition is formed, the curable fluoroelastomer composition comprising: The polyhydroxy curable fluoroelastomer; Curing agent of formula 1: wherein R1 and R5 are independently selected from the group consisting of: H, halogen, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy and X; wherein R2, R3 and R4 are independently selected from the group consisting of OH, H, halogen, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy and X, Provided that at least one of R2, R3 and R4 is OH; Provided that no more than 3 of R1, R2, R3, R4, and R5 are halogen; Wherein X is selected from the group consisting of Formula 2 and Formula 3: Among them, R6, R7, R8, R9 and R 10 independently selected from the group consisting of: H; C capable of being partially or fully halogenated 1-18 Alkyl; C can be partially or fully halogenated 1-18 alkoxy; partially or fully fluorinated phenyl, acetyl or methylsulfonyl which can be substituted by alkyl or aryl or partially or fully halogenated; nitro; nitrile; and halogen, provided that N can be substituted at exactly one of C2, C3 or C4, in which case the corresponding R6, R7 or R8 is absent; Where R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 independently selected from the group consisting of: H, C 1-18 Alkyl, partially or fully halogenated C 1-18 Alkoxy, nitro, nitrile and halogen, provided that R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 One of them is -(Y) n - Single button to connect; wherein Y is selected from the group consisting of: -SO2-, -C(O)-, -C(CF3)2-, and -O, and wherein n is 0 or 1; The condition is that at least one of R1, R2, R3, R4 and R5 is fluorine, fluorine-containing C 1-18 Alkyl, fluorinated C 1-18 Alkoxy or X; Provided that when X exists and R1, R2, R3, R4 and R5 are not fluorine, fluorine-containing C 1-18 Alkyl or fluorinated C 1-18 In the case of alkoxy, R6, R7, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 At least one of them is fluorine, fluorine-containing C 1-18 Alkyl or fluorinated C 1-18 Alkoxy; and Acid receptors; as well as The curable fluoroelastomer composition is heated to cure the polyhydroxy curable fluoroelastomer.

41. The method of claim 40 wherein the curable fluoroelastomer composition is free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

42. The method of claim 40 wherein the curable fluoroelastomer composition further comprises a cure accelerator.

43. The method of claim 42, wherein the curing accelerator is in the form of a salt that is pre-reacted with a portion of the curing agent.

44. The method of claim 43, wherein the curing agent is present in a three-fold to four-fold molar excess of the curing accelerator.

45. An article cured by the method of any one of claims 40 to 44.

46. ​​The article of claim 45, wherein the article is free or substantially free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

47. A compound of formula 1A: wherein one of R1 and R2 is H and the other is OH; wherein one of R3 and R4 is H and the other is selected from the group consisting of Formula 2A and Formula 3A: wherein R5, R6, R7, R8 and R9 are independently selected from the group consisting of: H, F, CF3, partially or fully fluorinated phenyl, OCF3, CH3, nitro and nitrile; Provided that at least one of R5, R6, R7, R8 and R9 is selected from the group consisting of: F, CF3, partially or fully fluorinated phenyl and OCF3; Provided that when R5, R6, R7, R8 and R9 are independently selected from the group consisting of H and F, at least two are H and at least two are F; Provided that when R1 is OH, R3 is of Formula 2A, and R5, R6, R7, R8 and R9 are independently selected from the group consisting of H and CF3, at least one of R6 and R8 is H; and Provided that N can be substituted at exactly one of C2, C3 or C4, in which case the corresponding R5, R6 or R7 is not present.

48. The compound of claim 47, wherein R1 is OH and R2 is H.

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