| 摘要 |
The novel process serves for the treatment of the surface of polyurethane compositions containing free NCO groups during their curing. To this end, said surface is brought into contact with a medium containing either a compound containing, per molecule, at least two hydrogen atoms which are reactive towards isocyanate or containing a compound containing, per molecule, one such reactive hydrogen atom and one alkoxysilane group, in such concentrations that, during the contact, the free NCO groups in the surface layer of the composition are modified in a stable manner. In particular, the surface is brought into contact either with water or compounds containing hydroxyl, sulphhydryl, carboxyl, hydrolysable alkoxysilane and/or primary or secondary amino groups or solutions of these compounds, or with a water/gas mixture, in particular a water vapour/air mixture having a relative humidity of greater than 50%, preferably greater than 70%. The polyurethane compositions are used, inter alia, as substrates for urethane prepolymer compositions containing free NCO groups to be applied to the modified surface layer and to be adhesively bonded thereto. A particularly important use of said compositions is on automobile windows, optionally pretreated with primer, for a ... to be applied to said surface layer for the purpose of installation and sealing of the window into the body and to be adhesively bonded to the surface layer... Original abstract incomplete. |
