Elastomer seal placed in groove of component of same visual colour - contg. stable UV fluorescent cpd. to facilitate identification

摘要

Seal of the type used between 2 components and placed in a groove in one of these is made from a mixt. based on elastomer (I) and the usual additives, and is of the same visual colour as the component with the groove. The novelty is that the mixt. contains 0.1-3 (wt.)%, w.r.t. (I), of a UV-fluorescent prod. (II), which is chemically stable at temps. of at least 200degC and pressures of at least 50 MPa. (II) is a solid, esp. powder, and pref. consists of 2,5-bis(5'-tert.-butyl-benzoxazol -2-yl)-thiophene. (I) is pref. a hydrogenated nitrile elastomer and the mixt. contains C black. USE/ADVANTAGE - The seal is claimed for sealing a car engine cylinder head cover, which pref. is black in colour. Although it is of the same colour as the component, it can be identified easily and quickly.