METHOD FOR PRODUCING FOAMS MADE OF POLYMERS OR POLYMER MIXTURES AND MOULDED ARTICLES MADE FROM SAID FOAMS

摘要

The present invention relates to a method for producing foams, mainly microcellular foams, made of polymers or polymer mixtures (13) and used in the production of moulded articles (21). In section (15) of the method, the polymers or polymer mixtures (13) are melted in an extruder and further guided through a shaping device (12), the foaming being carried out by gas introduction (14). To this end, the section (15) of the method is divided into at least a first (150) and a second part (151). The melting of the polymer or polymer mixture (13) takes place in the first part (150), and the introduction of the gas (14) under a pressure higher than that of the melt also takes place in the first part under the action of at least one shearing and/or kneading member (16) that acts on the polymer or polymer mixture (13) submitted to the action of the gas (14). At the end of the method's second part (151) that follows the first one (150), the method involves foaming the polymer or polymer mixture (13) which is submitted to the gas action and has an increased pressure relative to that in the first part (150). This method can be used for producing membranes in the form of moulded bodies.