Surface-treating agent for vulcanized rubber
A surface-treating agent for vulcanized rubber, comprising, based on 100 parts by weight, as solid matters, of isocyanate group-containing 1,2-polybutadiene, an organic solvent solution containing 10 to 160 parts by weight of fluororesin particles and 2.5 to 20 parts by weight of a perfluoroalkyl group-containing oligomer-based, fluorine-containing surfactant as a dispersant. The surface-treating agent for vulcanized rubber improves the solution stability of the organic solvent solution, improves the further hardness of the entire coating film formed from the surface-treating agent, abrasion resistance, and product torque evaluation, and is effectively used as, for example, a coating agent for seal lip parts of oil seals.
1. A surface-treating agent for vulcanized rubber wherein the surface-treating agent comprises, based on 100 parts by weight, as solid matters, of isocyanate group-containing 1,2-polybutadiene, an organic solvent solution containing 10 to 160 parts by weight of fluororesin particles and 2.5 to 20 parts by weight of a perfluoroalkyl group-containing oligomer-based, fluorine-containing surfactant as a dispersant, and further comprises, based on 100 parts by weight, as solid matters, of the isocyanate group-containing 1,2-polybutadiene, 100 parts by weight or less, as solid matters, of a composition solution of an OH group-containing fluororesin composition having the following formulation:
[I] a copolymer of
(A) a perfluoroalkylalkyl (meth)acrylate and
(B) a hydroxyl group-containing (meth)acrylate,
[II] a polymer of an acrylic acid alkyl ester,
[III] a polymer of a fluorinated olefin, and
[IV] a curing agent; and/or
60 parts by weight or less of silicone oil having a viscosity of 8,000 cs or more.
2. The surface-treating agent for vulcanized rubber according to claim 1 , which is used as a coating agent for a seal lip part of an oil seal.
3. An oil seal having a seal lip part having a coating film formed from the surface-treating agent for vulcanized rubber according to claim 2 .
4. An oil seal having a seal lip part having a coating film which is prepared by coating the seal lip part with the surface-treating agent for vulcanized rubber according to claim 2 , and then subjecting the coated seal lip to heat treatment at 150 to 250° C.
5. The surface-treating agent for vulcanized rubber according to claim 1 , which is used as a coating agent for a seal lip part of an oil seal.
6. An oil seal having a seal lip part having a coating film formed from the surface-treating agent for vulcanized rubber according to claim 5 .
7. An oil seal having a seal lip part having a coating film which is prepared by coating the seal lip part with the surface-treating agent for vulcanized rubber according to claim 5 , and then subjecting the coated seal lip to heat treatment at 150 to 250° C.