Direct adhesion of fluorinated rubbers to nickel-plated steel and nitrile rubber during curing using the tetrabutylammonium salt of 1,3,5-triazine-2,4,6-trithiol

Abstract

A new curing agent, the tetrabutylammonium salt of 1,3,5-triazine-2,4,6-trithiol (TATT) for fluorinated rubber (FR) has been developed, from the point of view of making composite materials with metals and other rubbers. TATT was inferior in curing rate compared with a conventional polyol curing system, but imparted good properties to FR vulcanizates to the same extent as the polyol curing system. TATT-containing FR compounds easily adhered to electro- and electroless nickel-plated metals during vulcanization without an adhesive. The optimum concentration of TATT was around 1 phr for the peel strength of joints and the mechanical properties of vulcanizates. At a thickness exceeding 0.3 μm, nickel platings were very effective for making FR-Ni joints. In the direct adhesion between FR and nickel platings, interfacial bonds and a reinforcing layer at the interface between vulcanizates and nickel platings during vulcanization were important for obtaining FR-Ni joints of high peel strength. The newly prepared FR-Ni joints had very good heat, oil, and water resistance, compared with conventional FR-Fe joints prepared by using phenol-type adhesives. TATT was also a very effective agent for the direct adhesion between FR and NBR (nitrile butadiene rubber) during vulcanization because it acted as a common curing agent to various rubbers such as FR and NBR. Thus, TATT is a very effective curing agent for making composites of FR with various metals and elastomers.