Elsner, P.P.ElsnerEyerer, P.P.EyererGeissler, A.A.Geissler2022-03-082022-03-081996https://publica.fraunhofer.de/handle/publica/303503In order to produce porous filter materials made of particulate, thermoplastic polymers, the invention proposes that at least part of the particles is added to a microwave-active agent, the particles are mixed and the mixture is exposed to a microwave field under the influence of mechanical pressure.de608660patent1994-4435887