Non-fluorinated resorcinol and hydroquinone analogs as curing agents for fluoroelastomers

Abstract

The composition comprises a curing agent of Formula 1: R1 and R5 are independently H, Cl, Br, C1-18 alkyl or alkoxy groups which can contain chlorine or bromine substitutions, or X. R < 2 > to R < 4 > are independently OH, H, Cl, Br, C1-18 alkyl or alkoxy which can contain chlorine or bromine substituent, or X. And at least one of R2, R3, and R4 is OH. And no more than three of R1-R5 are Cl or Br. X is a formula 2 or a formula 3: R6-R10 are independently H, Cl, Br, C1-18 alkyl or alkoxy capable of containing chlorine or bromine substitution, acetyl or methylsulfonyl capable of being substituted by alkyl or aryl or capable of containing chlorine or bromine substitution, nitro, nitrile, keto, acetyl or sulfone. R < 11 >-R < 18 > are independently H, Cl, Br, C1-18 alkyl or alkoxy which can contain chlorine or bromine substitutions, nitro or nitrile, wherein one of R < 11 >-R < 18 > is a single bond with-(Y) n-. Y is-SO2-or-O-, and n is 0 or 1. And at least one of R1-R5 is Cl, Br, C1-18 alkyl or alkoxy optionally containing chlorine or bromine substituent, or X. When X is present, at least one of R6-R18 is Cl, Br, C1-18 alkyl or alkoxy which may contain chlorine or bromine substituent, nitro, nitrile, keto, acetyl or sulfone. # imgabs0 #

Description

[0001] Citation of Related Applications

[0002] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 408,361, 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 non-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 containing monomer units of vinylidene fluoride (VF2) and monomer units of 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). Specific examples of PAVE include perfluoro (methyl vinyl ether), perfluoro (ethyl vinyl ether) and perfluoro (propyl vinyl ether). Other fluoroelastomers include copolymers of TFE and hydrocarbon olefins (such as ethylene or propylene). Perfluoroelastomers as copolymers of TFE and PAVE are known.

[0005] In order to fully develop the physical properties of the elastomer for use in molded elastomeric articles, the polymer must be cured, i.e., vulcanized or crosslinked. This is typically accomplished in connection with a molding process by mixing an 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 molded mixture to promote the crosslinking reaction of the curing agent with the polymer to produce a cured fluoroelastomer article.

[0006] Certain grades of fluoroelastomers (e.g., 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, commonly 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 "scorch," i.e., does not cure too quickly when the article is molded, but provides a desired short cure time once the article being molded begins to cure. In the cured fluoroelastomer article, BPAF imparts a desired low "compression set" property to the fluoroelastomer. Compression set is a common measurement of the ability of an elastomer to recover to near its original thickness after being compressed at elevated temperatures.

[0007] The European Union has currently proposed a restriction that includes BPAF in a class of compounds with endocrine disrupting properties. Therefore, it is desirable to use curing agents other than BPAF. In U.S. Pat. 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. Pat. No. 6,610,790 do not provide the good processing and compression set properties that can be provided by BPAF. Summary of the invention

[0008] The non-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 H, Cl, Br, C 1-18 alkyl or alkoxy and X, and R2, R3 and R4 are independently selected from OH, H, Cl, Br, C 1-18 The group consisting of alkyl or 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 Cl or Br.

[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 H, Cl, Br, C 1-18 The group consisting of alkyl or alkoxy, acetyl or methylsulfonyl which may be substituted by alkyl or aryl or may contain chlorine or bromine substitution, nitro, nitrile, keto, acetyl and sulfone; R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 independently selected from H, Cl, Br, C 1-18 The group consisting of alkyl or alkoxy, nitro and nitrile, 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 bond; Y is selected from the group consisting of -SO2- and -O-; and n is 0 or 1; provided that at least one of R1, R2, R3, R4 and R5 is Cl, Br, C 1-18 alkyl or alkoxy, or X, and provided that, when X is present, 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 Cl, Br, C which may contain chlorine or bromine substitution 1-18 Alkyl or alkoxy, nitro, nitrile, keto, acetyl or sulfone.

[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 to OH, at least one of the aforementioned groups 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 Cl or br.

[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 H, Cl, Br, C 1-18 alkyl or alkoxy and X; and R2, R3 and R4 are independently selected from OH, H, Cl, Br, C 1-18 The group consisting of an alkyl group or an alkoxy group 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 H, Cl, Br, C 1-6 alkyl or alkoxy, and R6, R7, R8, R9 and R 10 At least one of them is Cl, Br or C which can contain chlorine or bromine substitution 1-6 Alkyl or alkoxy.

[0024] In another embodiment of the composition, R6, R7, R8, R9 and R 10 are independently selected from the group consisting of H, Cl, Br and tert-butyl, and R6, R7, R8, R9 and R 10 At least one of them is Cl, Br or tert-butyl.

[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 from 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 dimer of hexafluoropropylene and vinylidene fluoride.

[0031] In another embodiment of the composition, the acid acceptor is selected from the group consisting of powdered magnesium oxide, calcium hydroxide, and combinations thereof.

[0032] In another embodiment of the composition, the curable fluoroelastomer composition is free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

[0033] 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 %.

[0034] In one embodiment of the fluoroelastomer masterbatch, the concentration of the curing agent is from about 20 wt % to about 40 wt %.

[0035] 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 quaternary phosphonium salts, quaternary ammonium salts, and tertiary sulfonium salts.

[0036] In one embodiment of the mixture of curing agent and curing accelerator, the curing accelerator is a tertiary sulfonium salt.

[0037] In another embodiment of the mixture of curing agent and curing accelerator, the curing accelerator is a quaternary ammonium salt.

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

[0039] In another embodiment of the mixture of curing agent and curing accelerator, the curing accelerator is a quaternary phosphonium salt.

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

[0041] In 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.

[0042] In one embodiment of the salt, the cure accelerator is a quaternary ammonium salt.

[0043] In another salt embodiment, the quaternary ammonium salt is tetrabutylammonium hydrogen sulfate.

[0044] In another embodiment of the salt, the cure accelerator is a quaternary phosphonium salt.

[0045] In another salt embodiment, the salt is a benzyltriphenylphosphonium salt.

[0046] 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.

[0047] In one embodiment of the method, the curable fluoroelastomer composition is free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

[0048] In another embodiment, the article is cured by the method.

[0049] In one embodiment of the article, the article is free or substantially free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

[0050] In another embodiment, a compound has Formula 1A.

[0051]

[0052] One of R1 and R2 is H, and the other is OH. One of R3 and R4 is H, and the other is Formula 2A:

[0053]

[0054] R5, R6, R7, R8 and R9 are independently selected from the group consisting of H, Cl, Br, OCH3, C(CH3)3, CH3, nitro, nitrile, keto, acetyl and sulfone, provided that when R1 is OH and R3 is Formula 2A: exactly one of R5, R6, R7, R8 and R9 is selected from the group consisting of C(CH3)3, nitrile, acetyl and sulfone, and the others are H; exactly one of R5, R6, R8 and R9 is selected from the group consisting of nitro and keto, and the others of R5, R6, R7, R8 and R9 are selected from the group consisting of is H; exactly one of R5 and R9 is CH3, and the rest of R5, R6, R7, R8 and R9 are H; exactly one of R6 and R8 is Br, and the rest of R5, R6, R7, R8 and R9 are H; or at least two of R5, R6, R7, R8 and R9 are independently selected from the group consisting of Cl, OCH3, C(CH3)3, nitro, nitrile, keto, acetyl and sulfone; provided that when R1 is OH and R4 is of formula 2A: exactly one of R5, R6, R7, R8 and R9 is selected R5, R6, R7, R8 and R9 are selected from the group consisting of C(CH3)3, nitrile, keto, acetyl and sulfone, and the rest are H; exactly one of R5, R6, R8 and R9 is selected from the group consisting of Cl, Br, OCH3 and CH3, and the rest of R5, R6, R7, R8 and R9 are H; exactly one of R5, R7 and R9 is nitro, and the rest of R5, R6, R7, R8 and R9 are H; or at least two of R5, R6, R7, R8 and R9 are independently selected from the group consisting of Cl, Br, OCH3, C(CH3)3, 3, CH3, keto, acetyl and sulfone; and with the condition that when R2 is OH: exactly one of R5, R6, R7, R8 and R9 is selected from the group consisting of keto and sulfone, and the others are H; exactly one of R5, R6, R8 and R9 is selected from the group consisting of C(CH3)3 and acetyl, and the others of R5, R6, R7, R8 and R9 are H; or at least two of R5, R6, R7, R8 and R9 are independently selected from the group consisting of Cl, C(CH3)3, nitrile, keto, acetyl and sulfone.

[0055] In one embodiment of the compound, R1 is OH and R2 is H.

[0056] In another embodiment of the compound, R1 is H and R2 is OH.

[0057] 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

[0058] Exemplary non-fluorinated resorcinol and hydroquinone analogs are provided that provide a good balance of processability and compression set properties as curing agents to replace BPAF in the cure of fluoroelastomers.

[0059] In an exemplary embodiment, the curing agent provides similar curing properties and cured fluoroelastomer properties as 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 time period 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 To M H Increase 50% S' torque (curing) time (t 50 ) and / or from M L To M H Increase 90% S' torque (curing) time (t 90 ). Such cured fluoroelastomer properties may include, but are not limited to, compression set resistance, tensile strength (TS), elongation at break (EB), and elastic modulus at 100% (M100) and / or fluid aging properties.

[0060] In an exemplary embodiment, the curing agent has Formula 1:

[0061]

[0062] Wherein R1 and R5 are independently selected from H, Cl, Br, C 1-18 alkyl or alkoxy and X, and R2, R3 and R4 are independently selected from OH, H, Cl, Br, C 1-18 The group consisting of alkyl or 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 Cl or Br;

[0063] Wherein X is selected from the group consisting of Formula 2 and Formula 3:

[0064]

[0065] Among them, R6, R7, R8, R9 and R 10 independently selected from H, Cl, Br, C 1-18The group consisting of alkyl or alkoxy, acetyl or methylsulfonyl which may be substituted by alkyl or aryl or may contain chlorine or bromine substitution, nitro, nitrile, keto, acetyl and sulfone; R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 independently selected from H, Cl, Br, C 1-18 The group consisting of alkyl or alkoxy, nitro, nitrile, keto, acetyl and sulfone, 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 bond; Y is selected from the group consisting of -SO2- and -O-; and n is 0 or 1; provided that at least one of R1, R2, R3, R4 and R5 is Cl, Br, C 1-18 alkyl or alkoxy, or X, and provided that, when X is present, 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 Cl, Br, C which may contain chlorine or bromine substitution 1-18 Alkyl or alkoxy, nitro, nitrile, keto, acetyl or sulfone.

[0066] In some embodiments, at least one of R1 and R5 is H.

[0067] In some embodiments, when at least one of R1, R2, R3, R4, and R5 is an adjacent substituent to OH, at least one of the foregoing groups is H.

[0068] In some embodiments, no more than one of R1, R2, R3, R4, and R5 is X.

[0069] In some embodiments, no more than 2 of R1, R2, R3, R4, and R5 are Cl or Br.

[0070] In some embodiments, only one of R2, R3, and R4 is OH.

[0071] In some embodiments, R2 or R4 is OH.

[0072] In some embodiments, one of R1, R2, R3, R4, and R5 is X and X is Formula 2.

[0073] In some embodiments, R6, R7, R8, R9 and R 10 independently selected from H, Cl, Br, C 1-6 Alkyl and C containing chlorine or bromine substitution 1-6 alkoxy group, and R6, R7, R8, R9 and R 10 At least one of them is Cl, Br, C which may contain chlorine or bromine substitution 1-6 Alkyl or C 1-6 Alkoxy.

[0074] In some embodiments, R6, R7, R8, R9 and R 10 are independently selected from the group consisting of H, Cl, Br and tert-butyl, and R6, R7, R8, R9 and R 10 At least one of them is fluorine or tert-butyl.

[0075] In some embodiments, n is 0.

[0076] In some embodiments, -Y- is -O-.

[0077] In some embodiments, the curing agent is a non-fluorinated resorcinol analog. Exemplary non-fluorinated resorcinol analogs may include, but are not limited to, the following structures:

[0078]

[0079] In some embodiments, the curing agent is a non-fluorinated hydroquinone analog. Exemplary non-fluorinated hydroquinone analogs include, but are not limited to, the following structures:

[0080]

[0081] In some embodiments, the curing agent is selected from the following structures:

[0082]

[0083] In some embodiments, the curing agent is part of a curable fluoroelastomer composition that also includes a polyhydroxy-curable fluoroelastomer and an acid acceptor.

[0084] In some embodiments, the curable fluoroelastomer composition comprises from about 0.1 to about 10 parts by weight, alternatively from about 0.2 to about 5 parts by weight, alternatively from about 0.5 to about 5 parts by weight, alternatively from about 1 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.

[0085] 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 elastomer polymer and fluoroelastomers containing sites that can be easily defluorinated. Fluoroelastomers in the back include, but are not limited to, those fluoroelastomers containing adjacent copolymerization units of vinylidene fluoride (VF2) and hexafluoropropylene (HFP), and fluoroelastomers containing adjacent copolymerization units of VF2 (or tetrafluoroethylene) and fluorinated comonomers (e.g., 2-hydropentafluoropropylene; 1-hydropentafluoropropylene; trifluoroethylene; 2,3,3,3-tetrafluoropropylene; or 3,3,3-trifluoropropylene) with acidic hydrogen atoms. 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-(trifluorovinyloxy)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- or bromine-containing elastomer. For example, small amounts (0.01 wt % to 1 wt %) of chlorine, bromine, or iodine may be introduced with a telogen (e.g., CH2I2 or I(CF2)4I) or a monomer (e.g., 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).

[0086] 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 from about 3 parts by weight to about 15 parts by weight, alternatively from about 5 parts by weight to about 15 parts by weight, alternatively from about 6 parts by weight to about 12 parts by weight, alternatively from 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 fluoroelastomer. In some embodiments, the composition comprises two or more acid acceptors.

[0087] In some embodiments, the curable composition comprises an organic base. Suitable organic bases may include, but are not limited to, 1,8-diazobicyclo[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.

[0088] In some embodiments, the curable composition includes one or more additives. Suitable additives may include, but are not limited to, processing aids and / or colorants.

[0089] In some embodiments, the fluoroelastomer masterbatch comprises a curing agent and a polyol-curable fluoropolymer.

[0090] In some embodiments, the curing agent and curing accelerator mixture includes a curing agent and a curing accelerator.

[0091] 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 - Quaternary ammonium, phosphonium, arsonium and antimonium salts, wherein Y is phosphorus, nitrogen, arsenic or antimony; R5, R6, R7 and R8 are each C1-C 20 Alkyl, aryl, aralkyl, alkenyl and their chlorine, fluorine, bromine, cyano, -OR and -COOR substituted analogs, R is C1-C 20 alkyl, aryl, aralkyl, alkenyl, and wherein X is a halide, hydroxide, sulfate, sulfite, carbonate, pentachlorothiophenate, tetrafluoroborate, hexafluorosilicate, hexafluorophosphate, dimethylphosphate, 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 triphenylarsonium tetrafluoroborate, tetraphenylantimony bromide, 4-chlorobenzyl triphenylphosphonium chloride, 8-benzyl-1,8-diazabicyclo(5.4.0)-7-undecenyl ammonium chloride, diphenylmethyl triphenylphosphonium chloride, allyl triphenylphosphonium chloride, tetrabutylphosphonium bromide, m-trifluoromethyl-benzyl trioctylphosphonium 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.

[0092] In some embodiments, the curing accelerator includes a quaternary phosphonium salt, a quaternary ammonium salt, or a tertiary sulfonium salt.

[0093] In some embodiments, the cure accelerator includes benzyltriphenylphosphonium chloride or tetrabutylammonium hydrogen sulfate.

[0094] 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.

[0095] 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 for use as a curing agent and cure accelerator for fluoroelastomers.

[0096] In some embodiments, a method cures a polyhydroxy-curable fluoropolymer with a curing agent.

[0097] 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.

[0098] In some embodiments, the mixture comprises from about 0.05 to about 1.5 parts by weight, alternatively from about 0.1 to about 1 parts by weight, alternatively from about 0.2 to about 0.8 parts by weight, alternatively from about 0.25 to about 0.65 parts by weight, of a cure accelerator per 100 parts by weight of fluoroelastomer, or any value, range, or sub-range therebetween.

[0099] In some embodiments, the mixture also includes a filler. The filler can be one or more inorganic fillers, one or more polymer fillers or a combination thereof. In some embodiments, the filler is medium thermal cracking 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 contains about 10 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 of fillers therebetween per 100 parts by weight of fluoroelastomer.

[0100] 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.

[0101] 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.

[0102] 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 50 and t 90 In some embodiments, these values ​​are 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 values ​​of BPAF as a curing agent.

[0103] 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, compression set resistance, tensile strength, elongation at break, and elastic modulus at 100%. In some embodiments, these values ​​are 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 values ​​of BPAF as the curing agent.

[0104] 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.

[0105] In some embodiments, the curable fluoroelastomer composition is free or substantially free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

[0106] In some embodiments, the article is cured by a curing method.

[0107] In some embodiments, the article is free or substantially free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

[0108] In another embodiment, a compound has Formula 1A:

[0109]

[0110] Wherein one of R1 and R2 is H, and the other is OH. One of R3 and R4 is H, and the other is Formula 2A:

[0111]

[0112] R5, R6, R7, R8 and R9 are independently selected from the group consisting of H, Cl, Br, OCH3, C(CH3)3, CH3, nitro, nitrile, keto, acetyl and sulfone, provided that when R1 is OH and R3 is Formula 2A: exactly one of R5, R6, R7, R8 and R9 is selected from the group consisting of C(CH3)3, nitrile, acetyl and sulfone, and the others are H; exactly one of R5, R6, R8 and R9 is selected from the group consisting of nitro and keto, and the others of R5, R6, R7, R8 and R9 are selected from the group consisting of is H; exactly one of R5 and R9 is CH3, and the rest of R5, R6, R7, R8 and R9 are H; exactly one of R6 and R8 is Br, and the rest of R5, R6, R7, R8 and R9 are H; or at least two of R5, R6, R7, R8 and R9 are independently selected from the group consisting of Cl, OCH3, C(CH3)3, nitro, nitrile, keto, acetyl and sulfone; provided that when R1 is OH and R4 is of formula 2A: exactly one of R5, R6, R7, R8 and R9 is selected R5, R6, R7, R8 and R9 are selected from the group consisting of C(CH3)3, nitrile, keto, acetyl and sulfone, and the rest are H; exactly one of R5, R6, R8 and R9 is selected from the group consisting of Cl, Br, OCH3 and CH3, and the rest of R5, R6, R7, R8 and R9 are H; exactly one of R5, R7 and R9 is nitro, and the rest of R5, R6, R7, R8 and R9 are H; or at least two of R5, R6, R7, R8 and R9 are independently selected from the group consisting of Cl, Br, OCH3, C(CH3)3, 3, CH3, keto, acetyl and sulfone; and with the condition that when R2 is OH: exactly one of R5, R6, R7, R8 and R9 is selected from the group consisting of keto and sulfone, and the others are H; exactly one of R5, R6, R8 and R9 is selected from the group consisting of C(CH3)3 and acetyl, and the others of R5, R6, R7, R8 and R9 are H; or at least two of R5, R6, R7, R8 and R9 are independently selected from the group consisting of Cl, C(CH3)3, nitrile, keto, acetyl and sulfone.

[0113] 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 (eg, watch bands).

[0114] 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.

[0115] Although curing agents for curing curable fluoroelastomers have been described herein, the curing agents may have other applications as well. In some embodiments, the curing agent reacts with a polyisocyanate to form a polyurethane.

[0116] 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 a mixture thereof) or an ester thereof to form an aliphatic-aromatic polyester or an aromatic-aromatic polyester, respectively. The resulting polymer may be an amorphous high T g Materials or liquid crystal aromatic polyesters. The introduction of fluorinated aromatic side groups may lead to good polymer processability, good thermal stability and / or good oxidative stability.

[0117] In other embodiments, the curing agent is contained in a polyimide, polyamide, polycarbonate, and / or epoxy resin.

[0118] Test Method

[0119] Moving Die Rheometer (MDR) Measurements

[0120] 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 swing amplitude was 0.5°.

[0121] The reported cure 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 .

[0122] Fluoroelastomer Performance Measurement

[0123] Compression set resistance of fluoroelastomers was determined according to ASTM D395, Test Method B, using a compression device 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 percent 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).

[0124] The tensile properties of unaged fluoroelastomers are determined by ISO 37:2005C or 1 2008 test protocol at 23° C. The tensile properties measured include tensile strength in MPa, elongation at break in %, and elastic modulus at 100% in MPa.

[0125] Example

[0126] Synthesis Example

[0127] Four non-fluorinated resorcinol or hydroquinone analogs were prepared as curing agents for evaluation. The chemical structures of these inventive examples are shown in Table 1.

[0128] Table 1: Chemical formula of the present invention

[0129]

[0130] The non-fluorinated resorcinol analogs of Examples 1, 3 and 4 of the present invention were prepared by a palladium catalyst-based synthesis method that is commonly used for the coupling of arylboronic acids with arylbromides as building blocks.

[0131] To synthesize Example 1 of the present invention, 4-chloro-phenylboronic acid (13.5 g, 86.4 mmol), 1-bromo-3,5-dimethoxy-benzene (15 g, 69 mmol), potassium carbonate (17.2 g), Pd(PPh3)4 (0.4 g, 0.35 mmol), water (60 g) and toluene (180 g) were stirred and refluxed under nitrogen for 4 hours. The resulting toluene solution was separated, washed with water, and dried over MgSO4. Toluene was removed by distillation, and the resulting (MeO)2C6H3-C6H4-4-Cl was distilled under vacuum (145°C-150°C / 1 Torr-1.3 Torr). The obtained (MeO)2C6H3-C6H4-4-Cl intermediate (13.33 g, yield 78%, 53.6 mmol) was hydrolyzed with 48% hydrobromic acid (40.4 g) and acetic acid (45 g) at a temperature of 114°C for 5 hours to achieve complete conversion. Most of the acid was removed by vacuum distillation, and the distillation residue was neutralized with 9 g of 25% NaOH aqueous solution, extracted with ethyl acetate, washed with NaHCO3 solution, and dried over MgSO4. The ethyl acetate was removed by distillation to obtain the final pure 3,5-(HO)2C6H3-C6H4-4-Cl (11.4 g, yield 96%, melting point = 141°C-144°C) of Example 1 of the present invention as a light yellow solid.

[0132] The material of Inventive Example 2 was obtained from Ambeed, Inc. (Arlington, IL, USA) and used without further purification.

[0133] To synthesize Example 3 of the present invention, 15.2 g (110.1 mmol) potassium carbonate and 0.64 g (0.55 mmol) Pd (PPh3) 4 were added to 15 g (55.7 mmol) 3,5-di-tert-butyl bromobenzene and 10 g (55.0 mmol) 3,5-dimethoxyphenyl boronic acid in a mixture of 150 mL dioxane and 50 mL deionized water under nitrogen. The reaction mixture was slowly refluxed for 24 hours while stirring, and the completion of the reaction was checked by TLC. Then, all solvents were evaporated, 300 mL deionized water was added, and the crude material was washed with water and dried. The crude material was redissolved in ether and filtered to remove the catalyst, the solvent was evaporated, and the remaining material was recrystallized from hexane. 13.1 g (73.2%) of product was obtained. The material (13g, 40.0mmol) obtained is dissolved in 100mL DCM cooled in an ice bath, and 10mL (105.4mmol) boron tribromide is added dropwise under vigorous stirring. The reaction mixture is slowly warmed to room temperature and stirred overnight. The solvent is removed, and the reaction mixture is quenched with cold water. The crude product is extracted with dichloromethane. The solution is dried over magnesium sulfate and filtered, and the solvent is evaporated. The residual material is recrystallized from hexane / ethyl acetate, and 10.3g of the embodiment of the present invention 3 is obtained, and the yield is 86.7%.

[0134] To synthesize Example 4 of the present invention, 3-nitro-phenylboronic acid (24.5 g, 146.7 mmol), 1-bromo-3,5-dimethoxy-benzene (24.5 g, 113 mmol), potassium carbonate (28 g), Pd(PPh3)4 (0.65 g, 0.56 mmol), water (98 g) and toluene (220 g) were stirred and refluxed under nitrogen for 4 hours. The resulting toluene solution was separated, washed with water, and dried over MgSO4. Toluene was removed by distillation, and after removing volatile components under vacuum (up to 190°C / 0.6 torr-0.9 torr), (MeO)2C6H3-C6H4-3-NO2 (20.8 g, yield 71.5%) was obtained as a distillation residue. The (MeO)2C6H3-C6H4-4-Cl intermediate (19.5 g, 75.2 mmol) was hydrolyzed with 48% hydrobromic acid (97 g) and acetic acid (93 g) at a temperature of 114°C for 5 hours and at 116°C for 3 hours. Most of the acid was removed by vacuum distillation, and the distillation residue was neutralized with 23 g of a 20% aqueous NaOH solution, extracted with ethyl acetate, washed with a NaHCO3 solution, and dried over MgSO4. The ethyl acetate was removed by distillation, and the crude 3,5-(HO)2C6H3-C6H4-3-NO2 was purified by silica gel chromatography, and Example 4 of the present invention was obtained as a recrystallized yellow solid (4.0 g, yield 23%, melting point = 176°C-178°C).

[0135] The melting points of the examples of the present invention were determined and are given in Table 2.

[0136] Table 2: Melting points of the embodiments of the present invention

[0137] Embodiments of the present invention Melting point(℃) 1 141-144 2 87 3 176-177 4 176-178

[0138] Comparative Fluoroelastomer Curing Example

[0139] Since the conditions of each set of curing tests were slightly different, 2,2-bis(4-hydroxyphenyl)hexafluoropropane (BPAF) (Comparative Examples AD) was used as the curing agent for each set of curing tests of the Examples of the present invention for comparing the curing agent.

[0140] The comparative fluoroelastomer curing composition comprises 100 parts by weight of Viton as a polyhydroxy-curable fluoroelastomer. TM A-500 (The 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 benzyltriphenolphosphonium chlorite (BTPPC) as a curing accelerator.

[0141] Curing Example of Fluorine-Containing Elastomer of the Present Invention

[0142] The prepared non-fluorinated resorcinol and hydroquinone analogs were evaluated as curing agents in curing compositions (Inventive Examples 1-4).

[0143] The fluorine-containing elastomer curing composition of the present invention comprises 100 parts by weight of Viton as a polyhydroxy-curable fluorine-containing elastomer. TM A-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, 1.24 to 2.01 parts by weight of a curing agent, and 0.30 to 0.60 parts by weight of BTPPC as a curing accelerator. The amounts of the curing agent and BTPPC used for each curing composition are shown in Table 3. The fluorine-containing elastomer curing composition of Example 4 of the present invention further includes 1 part by weight of a processing aid.

[0144] Table 3: Fluoroelastomer Curing Composition

[0145]

[0146]

[0147] In some cases, several tests were performed with the same curative, wherein the amounts of curative and BTPPC were adjusted based on previous results to obtain cure properties and / or fluoroelastomer properties more similar to those of BPAF used as the curative.

[0148] Fluoroelastomer Curing Results

[0149] The cure properties of the inventive examples of Table 1 and their corresponding comparative examples used in the cured compositions of Table 3 are shown in Table 4. Each comparative example is listed directly before the inventive examples from the same set of MDR tests. When multiple tests were performed with the same curing agent, only the test with the best combination of cure and fluoroelastomer properties was selected for inclusion in the table.

[0150] Table 4: Curing properties

[0151] Example A 1 B 2 C 3 D 4 <![CDATA[M L (dN·m)]]> 0.94 1.05 0.91 1.32 0.82 0.71 0.83 0.83 <![CDATA[M H (dN·m)]]> 23.78 23.98 23.84 25.46 22.58 22.92 23.13 23.45 ts1(min) 1.21 1.38 1.13 0.77 1.03 1.11 1.10 1.38 ts2(min) 1.25 1.62 1.27 0.89 1.13 1.28 1.24 1.65 <![CDATA[t 50 (min)]]> 1.56 2.16 1.58 1.41 1.39 1.71 1.57 2.34 <![CDATA[t 90 (min)]]> 2.15 2.90 2.20 2.78 1.85 2.36 2.52 3.84

[0152] Table 4 shows that the examples of the present invention provide curing properties similar to those of BPAF. Table 4 shows that for the examples of the present invention, M L The value is in the range of 0.71dN·m to 1.32dN·m, M H The value is in the range of 22.92 dN·m to 25.46 dN·m, the ts1 value is in the range of 0.77 min to 1.38 min, the ts2 value is in the range of 0.89 min to 1.65 min, and the t 50 The values ​​range from 1.41 minutes to 2.34 minutes, and t 90 The values ​​ranged from 2.36 minutes to 3.84 minutes.

[0153] Fluoroelastomer Properties

[0154] The fluoroelastomer properties of the fluoroelastomers formed from the inventive examples of Table 1 and the fluoroelastomers formed from their corresponding comparative examples in the cured compositions of Table 3 are shown in Table 5. When multiple runs were performed with the same curing agent, only the run with the best combination of cure and fluoroelastomer properties was selected for inclusion in the table.

[0155] Table 5: Fluoroelastomer properties

[0156] Example A 1 B 2 C 3 D 4 TS[MPa] 11.7 15.1 15.2 13.4 15.0 9.0 13.9 15.5 EB[%] 160 199 197 160 200 150 212 185 M 100[MPa] 6.3 6.9 6.3 7.3 6.1 5.5 5.1 6.9 CS1(%) 17.4 23.3 18.6 25.6 19.8 23.3 17.4 24.4 CS2 (%) 27.9 36 30.2 37.2 30.2 35.6 26.7 36.5 CS3 (%) 58.1 67.4 62.8 81.4 66.3 70.1 62.8 68.2

[0157] Table 5 shows that the inventive examples provide cured fluoroelastomers having properties similar to those of cured fluoroelastomers formed using BPAF as a curing agent. Table 5 shows that for the inventive examples, TS values ​​range from 9.0 MPa to 15.5 MPa, EB values ​​range from 150% to 199%, M100 values ​​range from 5.5 MPa to 7.3 MPa, CS1 values ​​range from 23.3% to 25.6%, CS2 values ​​range from 35.6% to 37.2%, and CS3 values ​​range from 64.7% to 81.4%.

[0158] All of the above references are hereby incorporated by reference.

[0159] 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 H, Cl, Br, C 1-18 Alkyl, C 1-18 A group consisting of an alkoxy group and X; Wherein R2, R3 and R4 are independently selected from OH, H, Cl, Br, C 1-18 Alkyl, C 1-18 A group consisting of an alkoxy group 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 Cl or Br; 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 H, Cl, Br, C 1-18 Alkyl, C 1-18 the group consisting of alkoxy, acetyl or methylsulfonyl which can be substituted by alkyl or aryl or can contain chlorine or bromine substitution, nitro, nitrile, keto, acetyl and sulfone; Where R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 independently selected from H, Cl, Br, C 1-18 Alkyl, C 1-18 The group consisting of alkoxy, nitro, nitrile, keto, acetyl and sulfone, 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 bond; wherein Y is selected from the group consisting of -SO2- and -O-; and Where n is 0 or 1; The condition is that at least one of R1, R2, R3, R4 and R5 is Cl, Br, chlorine-containing C 1-18 Alkyl or alkoxy, bromine-containing C 1-18 Alkyl or alkoxy, or X; Provided that, when X is present, 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 Cl, Br, C which may contain chlorine or bromine substitution 1-18 Alkyl, C 1-18 alkoxy, nitro, nitrile, keto, acetyl or sulfone; and Acid receptors.

2. The curable fluoroelastomer composition according to claim 1, wherein at least one of R1 and R5 is H.

3. The curable fluorinated elastomer composition according to claim 1 or 2, wherein when at least one of R1, R2, R3, R4 and R5 is a group adjacent to OH, at least one of the aforementioned groups 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 Cl or Br.

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 H, Cl, Br, C 1-18 Alkyl, C 1-18 alkoxy and X; and wherein R2, R3 and R4 are independently selected from OH, H, Cl, Br, C 1-18 Alkyl, C 1-18 A group consisting of an alkoxy group 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 H, Cl, Br, C 1-6 Alkyl and C 1-6 alkoxy group, and R6, R7, R8, R9 and R 10 At least one of them is Cl, Br, C which may contain chlorine or bromine substitution 1-6 Alkyl or 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, Cl, Br and tert-butyl, and R6, R7, R8, R9 and R 10 At least one of them is Cl, Br or tert-butyl.

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 of any of the preceding claims comprising 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 dimer of hexafluoropropylene and vinylidene fluoride.

17. 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.

18. 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.

19. A fluoroelastomer masterbatch comprising a polyhydroxy-curable fluoropolymer and a curing agent of Formula 1: Wherein R1 and R5 are independently selected from H, Cl, Br, C 1-18 Alkyl, C 1-18 A group consisting of an alkoxy group and X; Wherein R2, R3 and R4 are independently selected from OH, H, Cl, Br, C 1-18 Alkyl, C 1-18 A group consisting of an alkoxy group 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 Cl or Br; 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 H, Cl, Br, C 1-18 Alkyl, C 1-18 the group consisting of alkoxy, acetyl or methylsulfonyl which can be substituted by alkyl or aryl or can contain chlorine or bromine substitution, nitro, nitrile, keto, acetyl and sulfone; Where R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 independently selected from H, Cl, Br, C 1-18 Alkyl, C 1-18 The group consisting of alkoxy, nitro, nitrile, keto, acetyl and sulfone, 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 bond; wherein Y is selected from the group consisting of -SO2- and -O-; and Where n is 0 or 1; The condition is that at least one of R1, R2, R3, R4 and R5 is Cl, Br, chlorine-containing C 1-18 Alkyl or alkoxy, bromine-containing C 1-18 Alkyl or alkoxy, or X; Provided that, when X is present, 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 Cl, Br, C which may contain chlorine or bromine substitution 1-18 Alkyl, C 1-18 Alkoxy, nitro, nitrile, keto, acetyl or sulfone; The curing agent is present in a concentration of about 1 wt % to about 50 wt %.

20. The fluoroelastomer masterbatch of claim 19, wherein the concentration of the curing agent is from about 20 wt% to about 40 wt%.

21. 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 H, Cl, Br, C 1-18 Alkyl, C 1-18 A group consisting of an alkoxy group and X; Wherein R2, R3 and R4 are independently selected from OH, H, Cl, Br, C 1-18 Alkyl, C 1-18 A group consisting of an alkoxy group 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 Cl or Br; 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 H, Cl, Br, C 1-18 Alkyl, C 1-18 the group consisting of alkoxy, acetyl or methylsulfonyl which can be substituted by alkyl or aryl or can contain chlorine or bromine substitution, nitro, nitrile, keto, acetyl and sulfone; Where R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 independently selected from H, Cl, Br, C 1-18 Alkyl, C 1-18 The group consisting of alkoxy, nitro, nitrile, keto, acetyl and sulfone, 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 bond; wherein Y is selected from the group consisting of -SO2- and -O-; and Where n is 0 or 1; The condition is that at least one of R1, R2, R3, R4 and R5 is Cl, Br, chlorine-containing C 1-18 Alkyl or alkoxy, bromine-containing C 1-18 Alkyl or alkoxy, or X; Provided that, when X is present, 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 Cl, Br, C which may contain chlorine or bromine substitution 1-18 Alkyl, C 1-18 alkoxy, nitro, nitrile, keto, acetyl or sulfone; and A curing accelerator selected from the group consisting of quaternary phosphonium salts, quaternary ammonium salts and tertiary sulfonium salts.

22. The curing agent and curing accelerator mixture according to claim 21, wherein the curing accelerator is a tertiary sulfonium salt.

23. The curing agent and curing accelerator mixture according to claim 21, wherein the curing accelerator is a quaternary ammonium salt.

24. The curing agent and curing accelerator mixture according to claim 23, wherein the quaternary ammonium salt is tetrabutylammonium hydrogen sulfate.

25. The curing agent and curing accelerator mixture of claim 21, wherein the curing accelerator is a quaternary phosphonium salt.

26. The curing agent and curing accelerator mixture of claim 25, wherein the quaternary phosphonium salt is benzyltriphenylphosphonium chloride.

27. 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 H, Cl, Br, C 1-18 Alkyl, C 1-18 A group consisting of an alkoxy group and X; Wherein R2, R3 and R4 are independently selected from OH, H, Cl, Br, C 1-18 Alkyl, C 1-18 A group consisting of an alkoxy group 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 Cl or Br; 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 H, Cl, Br, C 1-18 Alkyl, C 1-18 the group consisting of alkoxy, acetyl or methylsulfonyl which can be substituted by alkyl or aryl or can contain chlorine or bromine substitution, nitro, nitrile, keto, acetyl and sulfone; Where R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 independently selected from H, Cl, Br, C 1-18 Alkyl, C 1-18 The group consisting of alkoxy, nitro, nitrile, keto, acetyl and sulfone, 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 bond; wherein Y is selected from the group consisting of -SO2- and -O-; and Where n is 0 or 1; The condition is that at least one of R1, R2, R3, R4 and R5 is Cl, Br, chlorine-containing C 1-18 Alkyl or alkoxy, bromine-containing C 1-18 Alkyl or alkoxy, or X; Provided that, when X is present, 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 Cl, Br, C which may contain chlorine or bromine substitution 1-18 Alkyl, C 1-18 Alkoxy, nitro, nitrile, keto, acetyl or sulfone.

28. The salt of claim 27, wherein the curing accelerator is a quaternary ammonium salt.

29. The salt of claim 28, wherein the quaternary ammonium salt is tetrabutylammonium hydrogen sulfate.

30. The salt of claim 27, wherein the cure accelerator is a quaternary phosphonium salt.

31. The salt of claim 30, wherein the salt is a benzyltriphenylphosphonium salt.

32. 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 H, Cl, Br, C 1-18 Alkyl, C 1-18 A group consisting of an alkoxy group and X; Wherein R2, R3 and R4 are independently selected from OH, H, Cl, Br, C 1-18 Alkyl, C 1-18 A group consisting of an alkoxy group 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 Cl or Br; 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 H, Cl, Br, C 1-18 Alkyl, C 1-18 the group consisting of alkoxy, acetyl or methylsulfonyl which can be substituted by alkyl or aryl or can contain chlorine or bromine substitution, nitro, nitrile, keto, acetyl and sulfone; Where R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 independently selected from H, Cl, Br, C 1-18 Alkyl, C 1-18 The group consisting of alkoxy, nitro, nitrile, keto, acetyl and sulfone, 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 bond; wherein Y is selected from the group consisting of -SO2- and -O-; and Where n is 0 or 1; The condition is that at least one of R1, R2, R3, R4 and R5 is Cl, Br, chlorine-containing C 1-18 Alkyl or alkoxy, bromine-containing C 1-18 Alkyl or alkoxy, or X; Provided that, when X is present, 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 Cl, Br, C which may contain chlorine or bromine substitution 1-18 Alkyl, C 1-18 alkoxy, nitro, nitrile, keto, acetyl or sulfone; and acid receptors; and The curable fluoroelastomer composition is heated to cure the polyhydroxy-curable fluoroelastomer.

33. The method of claim 32 wherein the curable fluoroelastomer composition is free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

34. An article cured by the method of claim 32.

35. The article of claim 34, wherein the article is free or substantially free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.

36. 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 of Formula 2A: wherein R5, R6, R7, R8 and R9 are independently selected from the group consisting of H, Cl, Br, OCH3, C(CH3)3, CH3, nitro, nitrile, keto, acetyl and sulfone; Provided that when R1 is OH and R3 is of formula 2A: Exactly one of R5, R6, R7, R8 and R9 is selected from the group consisting of C(CH3)3, nitrile, acetyl and sulfone, and the rest are H; Exactly one of R5, R6, R8 and R9 is selected from the group consisting of nitro and keto, and the rest of R5, R6, R7, R8 and R9 are H; Exactly one of R5 and R9 is CH3, and the rest of R5, R6, R7, R8 and R9 are H; Exactly one of R6 and R8 is Br, and the rest of R5, R6, R7, R8 and R9 are H; or At least two of R5, R6, R7, R8 and R9 are independently selected from the group consisting of Cl, OCH3, C(CH3)3, nitro, nitrile, keto, acetyl and sulfone; Provided that when R1 is OH and R4 is of formula 2A: Exactly one of R5, R6, R7, R8 and R9 is selected from the group consisting of C(CH3)3, nitrile, keto, acetyl and sulfone, and the rest are H; Exactly one of R5, R6, R8 and R9 is selected from the group consisting of Cl, Br, OCH3 and CH3, and the rest of R5, R6, R7, R8 and R9 are H; Exactly one of R5, R7 and R9 is nitro, and the rest of R5, R6, R7, R8 and R9 are H; or At least two of R5, R6, R7, R8 and R9 are independently selected from the group consisting of Cl, Br, OCH3, C(CH3)3, CH3, keto, acetyl and sulfone; and The condition is that when R2 is OH: Exactly one of R5, R6, R7, R8 and R9 is selected from the group consisting of keto and sulfone, and the rest are H; Exactly one of R5, R6, R8 and R9 is selected from the group consisting of C(CH3)3 and acetyl, and the rest of R5, R6, R7, R8 and R9 are H; or At least two of R5, R6, R7, R8 and R9 are independently selected from the group consisting of Cl, C(CH3)3, nitrile, keto, acetyl and sulfone.

37. The compound of claim 36, wherein R1 is OH and R2 is H.

38. The compound of claim 36, wherein R1 is H and R2 is OH.

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