Patent attributes
There is provided an adhesion mediator composition for use in the adhesion of silicone elastomers made from hydrosilylation curable silicone rubber compositions to thermoplastic substrates, especially polyolefin substrates. There is also provided a process for adhering silicone elastomers to thermoplastic substrates using the adhesion mediator composition. The adhesion mediator composition comprises: (i) a trialkoxysilane; (ii) a platinum group metal based hydrosilylation reaction catalyst; (iii) an alkoxy titanium compound; (iv) a tetraalkoxysilane; and (v): either (a′) a polyorganosiloxane containing at least two unsaturated groups; or (b′) a mixture of two or more polyorganosiloxanes containing at least two unsaturated groups. The method comprises the steps of: (a) optionally, activating a thermoplastic substrate surface; (b) treating the optionally activated thermoplastic substrate surface with the adhesion mediator composition; (c) applying a hydrosilylation curable silicone rubber composition on to the treated surface resulting from step (b); and (d) curing the hydrosilylation curable silicone rubber composition.
