Polymerizable fluid

Claim 1

A polymerisable fluid for application as a pre-applied coating on at least one of two mating surfaces and for subsequently sealing and locking said two mating surfaces after assembly thereof, wherein the polymerisable fluid contains the following components which allow two mechanisms for the initiation of polymerisation, a first of the mechanisms being initiatable by radiation: (a) at least one free radical curable monomer or oligomer (b) a photoinitiator capable of initiating the first mechanism to initiate polymerisation of the said monomer or oligomer upon exposure to ultraviolet or visible radiation (c) a second free radical polymerisation initiator capable of initiating the second mechanism to initiate polymerisation of said polymer or oligomer (d) an activator for the initiator (c), said second initiation mechanism being inhibited from activation by exposure to ultraviolet or visible radiation but being initiatable as a consequence of assembly of said two mating surfaces and (e) an opacifier which has the capacity to obstruct the transmission of the radiant energy of the said polymerisation initiating radiation to the extent that the radiation incident on a surface of the fluid in said pre-applied coating is extinguished near the said surface and initiates polymerisation by said first mechanism only in a surface layer of the fluid to form a dry-to-touch crust thereon while the fluid beneath the crust remains in a fluid state ready for polymerisation by said second mechanism upon assembly of said two mating surfaces.