FLUORINATED RESORCINOL AND HYDROQUINONE ANALOGS AS CURING AGENTS FOR FLUOROELASTOMERS
Compositions include a curing agent of a fluorinated resorcinol or hydroquinone of Formula 1: R 1 and R 5 are independently H, halogen, optionally partially or fully halogenated C 1-18 alkyl, optionally partially or fully halogenated C 1-18 alkoxy, or X. R 2 -R 4 are independently OH, H, halogen, optionally partially or fully halogenated C 1-18 alkyl, optionally partially or fully halogenated C 1-18 alkoxy, or X. At least one of R 2 , R 3 , and R 4 is OH. Not more than 3 of R 1 -R 5 are halogen. X is Formula 2 or Formula 3 as disclosed herein. Curable fluoroelastomer compositions, fluoroelastomer masterbatches, curing agent and curing accelerator mixtures, salts, and methods of curing a polyhydroxy-curable fluoroelastomer including a curing agent of a fluorinated resorcinol or hydroquinone of Formula 1 are also disclosed herein.
1 . A curable fluoroelastomer composition comprising:
a polyhydroxy-curable fluoroelastomer;
a curing agent of Formula 1:
wherein R 1 and R 5 are independently selected from the group consisting of H, halogen, C 1-18 alkyl which may be partially or fully halogenated, C 1-18 alkoxy which may be partially or fully halogenated, and X;
wherein R 2 , R 3 , and R 4 are independently selected from the group consisting of OH, H, halogen, C 1-18 alkyl which may be partially or fully halogenated, C 1-18 alkoxy which may be partially or fully halogenated, and X,
with the proviso that at least one of R 2 , R 3 , and R 4 is OH;
with the proviso that not more than 3 of R 1 , R 2 , R 3 , R 4 , and R 5 are halogen;
wherein X is selected from the group consisting of Formula 2 and Formula 3:
wherein R 6 , R 7 , R 8 , R 9 , and R 10 are independently selected from the group consisting of H, C 1-18 alkyl which may be partially or fully halogenated, C 1-18 alkoxy which may be partially or fully halogenated, partially or fully fluorinated phenyl, acetyl or methylsulfonyl which may be alkyl- or aryl-substituted or partially or fully halogenated, nitro, nitrile, and halogen, with the proviso that N may be substituted at exactly one of C 2 , C 3 , or C 4 in which case respective R 6 , R 7 , or R 8 is absent;
wherein R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , and R 18 are independently selected from the group consisting of H, C 1-18 alkyl which may be partially or fully halogenated, C 1-18 alkoxy which may be partially or fully halogenated, nitro, nitrile, and halogen with the proviso that one of R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , and R 18 is a single bond to —(Y) n —;
wherein Y is selected from the group consisting of —SO 2 —, —C(O)—, —C(CF 3 ) 2 —, and —O—; and
wherein n is 0 or 1;
with the proviso that at least one of R 1 , R 2 , R 3 , R 4 , and R 5 , is fluorine, a fluorine-containing C 1-18 alkyl, a fluorine-containing C 1-18 alkoxy, or X;
with the proviso that, when X is present and none of R 1 , R 2 , R 3 , R 4 , and R 5 is fluorine, a fluorine-containing C 1-18 alkyl, or a fluorine-containing C 1-18 alkoxy, at least one of R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , and R 18 is fluorine, a fluorine-containing C 1-18 alkyl, or a fluorine-containing C 1-18 alkoxy; and
an acid acceptor.
2 . The curable fluoroelastomer composition of claim 1 , wherein at least one of R 1 and R 5 is H.
3 . The curable fluoroelastomer composition of claim 1 , wherein at least one of R 1 , R 2 , R 3 , R 4 , and R 5 is H when it is an adjacent substituent to OH.
4 . The curable fluoroelastomer composition of claim 1 , wherein no more than one of R 1 , R 2 , R 3 , R 4 , and R 5 is X.
5 . The curable fluoroelastomer composition of claim 1 , wherein no more than 2 of R 1 , R 2 , R 3 , R 4 , and R 5 are halogen.
6 . The curable fluoroelastomer composition of claim 1 , wherein only one of R 2 , R 3 , and R 4 is OH.
7 . The curable fluoroelastomer composition of claim 6 , wherein either R 2 or R 4 is OH.
8 . The curable fluoroelastomer composition of claim 1 , wherein R 1 and R 5 are selected from the group consisting of H, fluorine, C 1-18 alkyl which may be partially or fully fluorinated, C 1-18 alkoxy which may be partially or fully fluorinated, and X; and wherein R 2 , R 3 , and R 4 are independently selected from the group consisting of OH, H, fluorine, C 1-18 alkyl which may be partially or fully fluorinated, C 1-18 alkoxy which may be partially or fully fluorinated, and X.
9 . The curable fluoroelastomer composition of claim 1 , wherein one of R 1 , R 2 , R 3 , R 4 , and R 5 is X, and X is Formula 2.
10 . The curable fluoroelastomer composition of claim 9 , wherein R 6 , R 7 , R 8 , R 9 , and R 10 are independently selected from the group consisting of H, fluorine, C 1-6 alkyl which may be partially or fully fluorinated, and C 1-6 alkoxy which may be partially or fully fluorinated, and at least one of R 6 , R 7 , R 8 , R 9 , and R 10 is fluorine, C 1-6 alkyl which may be partially or fully fluorinated, or C 1-6 alkoxy which may be partially or fully fluorinated.
11 . The curable fluoroelastomer composition of claim 9 , wherein R 6 , R 7 , R 8 , R 9 , and R 10 are independently selected from the group consisting of H, fluorine, perfluoromethyl, and perfluoromethoxy, and at least one of R 6 , R 7 , R 8 , R 9 , and R 10 is fluorine, perfluoromethyl, or perfluoromethoxy.
12 . The curable fluoroelastomer composition of claim 1 , wherein n is 0.
13 . The curable fluoroelastomer composition of claim 1 , 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 claim 1 containing about 0.1 to about 10 parts by weight of said curing agent per 100 parts by weight of said polyhydroxy-curable fluoroelastomer.
16 . The curable fluoroelastomer composition of claim 1 , wherein the polyhydroxy-curable fluoroelastomer is a copolymer of hexafluoropropylene and vinylidene fluoride.
17 . The curable fluoroelastomer composition of claim 1 , wherein the polyhydroxy-curable fluoroelastomer is a terpolymer of hexafluoropropylene, vinylidene fluoride, and tetrafluoroethylene.
18 . The curable fluoroelastomer composition of claim 1 , wherein the acid acceptor is selected from the group consisting of powdered magnesium oxide, calcium hydroxide, and a combination thereof.
19 . The curable fluoroelastomer composition of claim 1 , wherein the curable fluoroelastomer composition is free of 2,2-bis(4-hydroxyphenyl)hexafluoropropane.
20 . The curable fluoroelastomer composition of claim 1 further comprising a curing accelerator.
21 . The curable fluoroelastomer composition of claim 20 , wherein the curing accelerator is in the form of a pre-reacted salt with a portion of the curing agent.
22 . The curable fluoroelastomer composition of claim 21 , wherein the curing agent is present in a threefold to fourfold molar excess of the curing accelerator.