CURABLE FLUOROPOLYMER COMPOSITIONS
Polyhydroxy curable fluoropolymer compositions comprise polyhydroxy curable fluoropolymer, a β-fluoroalcohol having the formula R—(CF 2 )n-CH 2 —OH, wherein R is H, F or CH 3 O and n is an integer from 2 to 7, a polyhydroxy curative, acid acceptor and accelerator.
1 . A curable composition comprising:
A) a polyhydroxy curable fluoropolymer, said fluoropolymer containing 0 to 0.01 weight percent, based on total weight of fluoropolymer, of peroxide cure sites selected from the group consisting of chlorine atoms, bromine atoms and iodine atoms;
B) 1 to 50 parts by weight per 100 parts by weight fluoropolymer of a β-fluoroalcohol having the formula R—(CF 2 ) n —CH 2 —OH wherein R is H, F or CH 3 O, and n is an integer from 2 to 7;
C) a polyhydroxy curative;
D) an acid acceptor; and
E) an accelerator.
2 . A curable composition of claim 1 wherein said fluoropolymer is crystalline.
3 . A curable composition of claim 1 wherein said fluoropolymer is amorphous.
4 . A curable composition of claim 3 wherein said fluoropolymer is a fluoroelastomer.
5 . A curable composition of claim 4 wherein said fluoroelastomer is selected from the group consisting of copolymers of i) vinylidene fluoride with hexafluoropropylene and, optionally, tetrafluoroethylene; ii) vinylidene fluoride with a perfluoro(methyl vinyl ether), 2-hydropentafluoroethylene and optionally, tetrafluoroethylene; iii) tetrafluoroethylene with propylene and 3,3,3-trifluoropropene; 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.
6 . A curable composition of claim 1 wherein said β-fluoroalcohol is selected from the group consisting of 2,2,3,3-tetrafluoro-1-propanol; 2,2,3,3,3-pentafluoro-1-propanol; 1H,1H,5H octafluoro-1-pentanol; 1H,1H,7H dodecafluoro-1-heptanol; and 3-methoxy-2,2,3,3-tetrafluoro-1-propanol.
7 . A curable composition of claim 1 wherein said polyhydroxy curative is selected from the group consisting of i) dihydroxy-, trihydroxy-, and tetrahydroxy-benzenes, -naphthalenes, and -anthracenes;
ii) bisphenols of the formula
where A is a stable divalent radical; x is 0 or 1; and n is 1 or 2;
iii) dialkali salts of said bisphenols, iv) quaternary ammonium and phosphonium salts of said bisphenols, v) tertiary sulfonium salts of said bisphenols, and vi) esters of phenols.
8 . A curable composition of claim 1 wherein said accelerator is selected from the group consisting of quaternary ammonium salts, tertiary sulfonium salts and quaternary phosphonium salts.
9 . A curable composition of claim 1 wherein said acid acceptor is selected from the group consisting of calcium oxide, magnesium oxide and mixtures thereof.
10 . A method for producing a shaped, cured article comprising the steps:
A) providing a curable composition comprising
i) a polyhydroxy curable fluoropolymer;
ii) 1 to 50 parts by weight per 100 parts by weight fluoropolymer of a β-fluoroalcohol having the formula R—(CF 2 ) n —CH 2 —OH wherein R is H, F or CH 3 O, and n is an integer from 2 to 7;
iii) a polyhydroxy curative;
iv) an acid acceptor; and
v) an accelerator;
B) shaping said curable composition to form a curable shaped article; and
C) heating said curable shaped article to a temperature of at least 100° C. to cure said shaped article.
11 . A method of claim 10 wherein said steps B) and C) occur in sequence.
12 . A method of claim 10 wherein said steps B) and C) occur simultaneously.
13 . A method of claim 10 wherein said fluoropolymer is crystalline.
14 . A method of claim 10 wherein said fluoropolymer is amorphous.
15 . A method of claim 14 wherein said fluoropolymer is a fluoroelastomer.
16 . A method of claim 15 wherein said fluoroelastomer is selected from the group consisting of copolymers of i) vinylidene fluoride with hexafluoropropylene and, optionally, tetrafluoroethylene; ii) vinylidene fluoride with a perfluoro(methyl vinyl ether), 2-hydropentafluoroethylene and optionally, tetrafluoroethylene; iii) tetrafluoroethylene with propylene and 3,3,3-trifluoropropene; 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.
17 . A method of claim 10 wherein said β-fluoroalcohol is selected from the group consisting of 2,2,3,3-tetrafluoro-1-propanol; 2,3,3,3-pentafluoro-1-propanol; 1H,1H,5H octafluoro-1-pentanol; 1H,1H,7H dodecafluoro-1-heptanol; and 3-methoxy-2,2,3,3-tetrafluoro-1-propanol.
18 . A method of claim 10 wherein said polyhydroxy curative is selected from the group consisting of i) dihydroxy-, trihydroxy-, and tetrahydroxy-benzenes, -naphthalenes, and -anthracenes;
ii) bisphenols of the formula
where A is a stable divalent radical; x is 0 or 1; and n is 1 or 2;
iii) dialkali salts of said bisphenols, iv) quaternary ammonium and phosphonium salts of said bisphenols, v) tertiary sulfonium salts of said bisphenols, and vi) esters of phenols.
19 . A method of claim 10 wherein said accelerator is selected from the group consisting of quaternary ammonium salts, tertiary sulfonium salts and quaternary phosphonium salts.
20 . A method of claim 10 wherein said acid acceptor is selected from the group consisting of calcium oxide, magnesium oxide and mixtures thereof.