AdhesionDuring fabrication of composite parts, urethane can readily be adhered to many metals, elastomers and plastics with bond strengths which often exceed even the tear strength of urethane itself. It is difficult to bond cured urethane to another material, but special techniques have been developed to satisfy most requirements.
Surfaces should be completely free of oil, grease and oxide film. Grit blasting to roughen the surface and degreasing is recommended followed by a coating of an adhesion primer to protect the source from oxidation and moisture during storage. A fresh coat of primer should be applied before casting the urethane.
Good bonds between urethane and other elastomers can be obtained by first removing traces of oil, greases and mold release agent from the elastomer and then roughening the surface with sandpaper, sandblasting or other abrasives. An adhesive primer is then applied to the surface by brushing, spraying or roll coating and urethane cast against it or adhered with pressure if the urethane has been cured.
Many adhesives and primers are used with urethane.