Curable perfluoropolyether based gel composition and gel product using cured composition
A curable perfluoropolyether based gel composition is provided comprising (A) a linear fluorinated polymer containing at least two alkenyl groups, (B) a polyfluoromonoalkenyl compound containing one alkenyl group and having a perfluoropolyether structure in its backbone, (C) a cyclic organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms and at least one perfluoroalkyl group or perfluoropolyether structure-containing group, and (D) a hydrosilylation reaction catalyst. The composition cures into a gel having improved acid resistance as well as heat resistance, solvent resistance, chemical resistance, weatherability, parting property, and water/oil repellency.
1. A curable perfluoropolyether based gel composition comprising
(A) a linear fluorinated polymer containing at least two alkenyl groups per molecule, represented by the formula (1):
wherein R 1 is each independently vinyl or C 1 -C 4 alkyl, R 2 is each independently C 1 -C 6 alkylene, R 3 is each independently hydrogen or optionally fluorinated C 1 -C 4 alkyl, and Rf 1 is a perfluoroalkylene group or divalent perfluoropolyether structure-containing group,
(B) a polyfluoromonoalkenyl compound containing one alkenyl group per molecule and having a perfluoropolyether structure in its backbone,
(C) a cyclic organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms and at least one perfluoroalkyl group or perfluoropolyether structure-containing group per molecule, represented by the formula (2):
wherein Rf 2 is a perfluoroalkyl group or monovalent perfluoropolyether structure-containing group, R 4 is each independently a C 1 -C 20 monovalent hydrocarbon group, R 5 is a C 2 -C 20 divalent hydrocarbon group which may contain an ether bond, amide bond, carbonyl bond, silyl radical or ester bond, k is an integer of 2 to 4, l is an integer of 1 to 3, and k+l is 5, and
(D) a hydrosilylation reaction catalyst.
2. The curable perfluoropolyether based gel composition of claim 1 wherein component (C) is a hydrogenpolysiloxane of the following formula:
wherein L is an integer of 1 to 200.
3. The curable perfluoropolyether based gel composition of claim 1 , further comprising (E) at least one perfluoropolyether compound selected from the general formulae (3) to (5):
A-O—(CF 2 —CF 2 —CF 2 —O) d -A (3)
wherein A is a group: C e F 2e+1 —, d is an integer of 1 to 500, e is an integer of 1 to 3,
A-O—(CF 2 —O) f —(CF 2 —CF 2 —O) h -A (4)
wherein A is as defined above, f and h each are an integer of 1 to 300,
wherein A is as defined above, i and j each are an integer of 1 to 300.
4. The curable perfluoropolyether based gel composition of claim 1 which cures into a mass having a penetration of 1 to 200 according to JIS K 2220 or ASTM D-1403.
5. The curable perfluoropolyether based gel composition of claim 1 which cures into a mass that shows a residual solid content of at least 90% by weight after it is immersed in conc. sulfuric acid (98%) at 40° C. for 1,000 hours, and a penetration change of up to 25 after it is immersed in conc. nitric acid (60%) at 40° C. for 2,000 hours.
6. A gel product comprising a cured mass of the curable perfluoropolyether based gel composition of claim 1 .
7. The gel product of claim 6 which is suited for use in automobiles, chemical plants, inkjet printers, semiconductor fabrication lines, analyzers, scientific instruments, medical instruments, aircraft, or fuel cells.