Fluoropolymer compositions

Abstract

A catalyst composition includes a compound having the general formula: {RA} (−) {QR′ k } (+) or the precursors thereof, wherein R is a nonfluorinated, partially fluorinated, or perfluorinated alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl or aralkyl, A is an acid- or acid-derivative anion, Q is phosphorous, sulfur, nitrogen, arsenic, or antimony, and each R′ is hydrogen or an alkyl, aryl, aralkyl, or alkenyl group, k is the valence of Q; and optionally (c) an alcohol of the formula: R 2 —OH, wherein R 2 is an alkyl group which can be fluorinated. Also provided are curable and cured fluoropolymer compositions involving such a catalyst.

1 . A composition suitable for curing a fluoropolymer comprising a catalyst composition that includes a compound having the general formula:  
         {R(A) n } (−n) {QR′ k   (+) } n    or the precursors thereof added separately or as a mixture; wherein R is a C 1 -C 20  alkyl or alkenyl, C 3 -C 20  cycloalkyl or cycloalkenyl, or C 6 -C 20  aryl or aralkyl, which may be nonfluorinated, partially fluorinated, or perfluorinated, {R(A) n } (−n)  is an acid anion or an acid derivative anion, n is the number of A groups in the anion, Q is phosphorous, sulfur, nitrogen, arsenic, or antimony, each R′ is, independently, hydrogen or a substituted or unsubstituted C 1 -C 20  alkyl, aryl, aralkyl, or alkenyl group, provided that when Q is nitrogen and the only fluoropolymer in the composition consists essentially of a terpolymer of tetrafluoroethylene, a perfluorovinylether, and a perfluorovinylether cure site monomer comprising a nitrile group not every R′ is H, and k is one greater than the valence of Q; and optionally (c) an alcohol of the general formula R 2 —OH, wherein R 2  is an alkyl group having from 1 to 20 carbon atoms, and wherein R 2  optionally is fluorinated.    
     
     
         2 . A composition according to  claim 1  wherein A is selected from the group consisting of: COO, 0 when R is aryl or alkylaryl, SO 3 , SO 2 , SO 2 NH, PO 3 , CF 3 CF(CF 3 )CH 2 O, C n F 2n+1 CH 2 O wherein n is 0 to 100, CH 2 OPO 3 , (CH 2 O) 2 PO 2 , C 6 H 4 O,  
       
         
           
           
               
               
           
         
       
       wherein R′ is as defined in  claim 1 .  
     
     
         3 . A composition according to  claim 1  wherein a precursor of R(A) n  has the general formula selected from the group consisting of RCOOM, ROSO 3 M, RSO 3 M, and ROM, wherein M is hydrogen, or an alkali or alkaline earth metal.  
     
     
         4 . A composition according to  claim 1  wherein R(A) n  is selected from the formula (R″) x —Ph y -{(CH 2 ) n -D} m  wherein each R″ is the same or different C 1 -C 10  alkenyl or alkyl, x is 0 to 5, y is 0 or 1, n is 0 to 10, m is 1 to 5, and D is selected from COO, OSO 3 , SO 3 , and 0 (when y is 1), provided that the sum of x and m is 6 or less and provided that x and y are not both zero; RCOO wherein R is alkenyl, an alkyl of 1 to 10 carbon atoms, or an aryl of 6 to 20 carbon atoms;  (−) OOC—(CX 2 ) t —COO (−)  wherein t is 0 to 10, X═H, F, or Cl; and 
 Ph-((CH 2 ) p —COO (−) ) q  wherein p and q are independently 1 to 4; CF 3 CF(CF 3 )CH 2 O or C d F 2d+1 CH 2 O wherein d is 0 to 100; and blends of two or more such compounds.    
     
     
         5 . A composition according to  claim 1  wherein R(A) n  is selected from the general formula  (−) O z Ph-G y -Ph-O z   (−) wherein g is a bond or a difunctional aliphatic, cycloaliphatic, or C   1 -C 13  aromatic radical, or a thio, oxy, carbonyl, sulfinyl, or sulfonyl radical, G and/or Ph are optionally substituted with at least one Cl or F atom, y is 0 or 1, each z is, independently, 1 or 2, and any aromatic ring of the polyoxy compound is optionally substituted with at least one atom of Cl, F, or Br atom, or carboxyl, or an acyl radical, or an alkyl radical; and blends of two or more such compounds.  
     
     
         6 . A composition according to  claim 1  wherein R(A) n  is selected from the general formula  (−) O-Ph-C(CX 3 ) 2 -Ph-O (−) , wherein X is H, Cl, or F; and blends of two or more such compounds.  
     
     
         7 . A composition according to  claim 1  wherein a precursor of QR′ k  is selected from the group consisting of tetramethylphosphoniums, tributylallylphosphoniums, tributylbenzylphosphoniums, dibutyldiphenylphosphoniums, tetrabutylphosphonium, tributyl(2-methoxy)propylphosphoniums, triphenylbenzylphosphoniums, and tetraphenylphosphoniums.  
     
     
         8 . A composition according to  claim 1  wherein a precursor of QR′ k  is selected from the group consisting of phenyltrimethylammoniums, tetrapentylammoniums, tetrapropylammoniums, tetrahexylammoniums, tetraheptylammoniums, tetramethylammoniums, tetrabutylammoniums, tributylbenzyl ammoniums, tributylallylammoniums, tetrabenzylammoniums, tetraphenylammoniums, diphenyl diethylamino ammoniums, triphenylbenzylammoniums, 8-benzyl-1,8-diazabicyclo[5.4.0]undec-7-eniums, benzyltris(dimethylamino)phosphoniums, and bis(benzyldiphenyl phosphine)iminiums.  
     
     
         9 . A composition of  claim 1  wherein the catalyst composition is prepared in situ.  
     
     
         10 . A composition according to  claim 1  wherein the catalyst composition is prepared from components dissolved in a solvent.  
     
     
         11 . A composition according to  claim 1  further comprising a fluoropolymer comprising interpolymerized units derived from tetrafluoroethylene, and one or more perfluorovinyl ethers of the formula CF 2 ═CFO(R 2   f O) a (R 3   f O) b R 4 , wherein R 2   f  and R 3   f  are the same or are different linear or branched perfluoroalkylene groups of 1-6 carbon atoms; a and b are, independently, 0 or an integer from 1 to 10; and R 4   f  is a perfluoroalkyl group of 1-6 carbon atoms.  
     
     
         12 . A composition according to  claim 11  wherein the fluoropolymer further comprises interpolymerized units derived from monomers selected from the group consisting of perfluoroolefins, partially-fluorinated olefins, non-fluorinated ole fins, vinylidene fluoride, and combinations thereof.  
     
     
         13 . A composition according to  claim 1  wherein said cure site monomer is selected from a fluorinated olefin and a nitrile-containing monomer.  
     
     
         14 . A composition according to  claim 1  wherein said cure site monomer is a nitrile-containing monomer having the formula CF 2 ═CFO(CF 2 )LCN; 
 CF 2 ═CFO(CF 2 ) u OCF(CF 3 )CN; CF 2 ═CFO[CF 2 CF(CF 3 )O]q(CF 2 O) y CF(CF 3 )CN; or    CF 2 ═CF[OCF 2 CF(CF 3 )] r O(CF 2 ) t CN;    wherein L=2-12; q=0-4; r=1-2; y=0-6; t=1-4, and u=2-6; and perfluoro(8-cyano-5-methyl-3,6-dioxa-1-octene).    
     
     
         15 . A composition according to  claim 11  further comprising a filler selected from fluoropolymer filler, carbon black, and combinations thereof.  
     
     
         16 . The composition of  claim 11  wherein the composition has an induction time below about 15 minutes at a temperature of about 175° C.  
     
     
         17 . The composition of  claim 11  wherein the composition has a scorch resistance greater than the scorch resistance of a comparative composition tested at the same temperature, which comparative composition has the same fluoropolymer composition of  claim 1  but with a urotropin curative.  
     
     
         18 . The catalyst composition of  claim 1  comprising a material selected from: 0° C.—(CF 2 ) n —COO wherein n is an integer from 1 to 10, OOC(CF 2 ) 4 —COO, tributyl-(2-methoxy)-propyl phosphonium perfluoro butyrate, tributyl-(2-methoxy)-propyl phosphonium perfluoro propanoate, tributyl-(2-methoxy)-propyl phosphonium acetate, and combinations thereof.  
     
     
         19 . The catalyst composition of  claim 1  further comprising an alcohol.  
     
     
         20 . A shaped article comprising the fluoropolymer composition of  claim 11 , which article optionally is cured.