Patent ID: 7285315

Claim:
A wine bottle stopper made of an expanded elastomer selected from the group consisting of styrene-based block copolymers, hydrogenated styrene-based block copolymers and mixtures thereof with polyolefins, the wine bottle stopper being made by means of a thermal moulding method, wherein the expanded elastomer is produced by expanding a polymeric material with nitrogen in its supercritical state, the thermal moulding method comprising the steps of: (a) providing a source of supercritical nitrogen at a temperature and at a pressure greater than the critical temperature and pressure of the supercritical nitrogen, (b) preheating the polymeric material to a temperature above the critical temperature of the supercritical nitrogen, preferably to the softening point or melting point of the polymeric material, (c) saturating the polymeric material, preheated in step (b), with the supercritical nitrogen whilst maintaining a temperature and a pressure greater than the critical temperature and pressure of the supercritical nitrogen in a saturation chamber, preferably mixing the preheated polymeric material and the supercritical nitrogen in the chamber so as to facilitate the saturation process, (d) injecting the polymeric material, preheated and saturated with the supercritical nitrogen, into a mould for wine bottle stoppers, reducing the pressure to a pressure below the critical pressure of the supercritical nitrogen, and (e) keeping the polymeric material in the mould until the forming of the stopper is completed.