Abstract: An process for producing thin silicone by extrusion of a layer of silicone. The silicone layer may be extruded onto a substrate layer. The silicone layer and the substrate layer may be extruded together out of an extrusion die.

Abstract: In the present invention, an actuating mechanism for a hand held canister is provided in which a slider is moveable by finger pressure from a valve-disengaged position into a valve-engagable position and a concealed spring returns the slider to a valve-disengaged position when finger pressure is removed. The spring is preferably molded with the slider, projects through a slit in the over-cap of the canister and acts in a vertical plane against a stop depending from the over-cap. It is energised when the slider is moved into the valve engagable position. The slider is preferably releasably locked in the valve disengaged position.

Abstract: Hand held aerosol canisters can be accidentally discharged if the valve remains open after hand pressure is removed.

Abstract: The invention comprises a hollow body, suitable for receiving diffusible substances and made of plastics material coated with varnish resins, the external surface of which has a roughness, measured in profile according to DIN 4768, Part I, of Rz=from 2 to 150 .mu.m and R.sub.max =from 5 to 250 .mu.m on which a coating, positively linked with that surface to provide a seal against diffusion of liquids and gases present in the body, consisting of a chemically crosslinked polyurethane resin is located in a layer thickness of from 10 to 800 .mu.m.