Abstract: A method for processing thermoplastics in a shaping device, whereby before and/or during its passage in the shaping device the thermoplastic is submitted to a static electrical field.

Abstract: A method for processing thermoplastics in a shaping device, whereby before and/or during its passage in the shaping device the thermoplastic is submitted to a static electrical field.

Abstract: A method for processing thermoplastics in a shaping device, whereby before and/or during its passage in the shaping device the thermoplastic is submitted to a static electrical field.

Abstract: A method for processing thermoplastics in a shaping device, whereby before and/or during its passage in the shaping device the thermoplastic is submitted to a static electrical field.

Abstract: These novel molds are characterized in that they contain a cavity in porous material which is not monolithic, but which, on the contrary, is constituted by zones B with high capillary forces and by zones A with low capillary forces for liquids. The process of using these novel molds is useful for the manufacture of expanded plastics articles.

Abstract: A two part waveguide consists of a fixed part formed of a metal sleeve provided with metal dividing walls and a movable part formed by a helix positioned within the sleeve and rotatable sleeve about an axis coaxial with the axis of the cylindrical sleeve. A plurality of magnetrons are positioned on the outer surface of the sleeve. The sleeve includes two openings, one for admitting material to be treated and the other for discharging the material to be treated. The openings are dimensioned so that the microwaves cannot leave the waveguide.

Abstract: Molding of expanded plastic material such as dielectric material by microwave radiation is effected in a mold in which the part of the mold which contacts the material to be molded is of a material having high dielectric losses and capable of absorbing microwave radiation. Such mold portion preferably comprises a resin containing a small amount of carbon black.

Abstract: The present invention provides an apparatus for the manufacture of pre-expanded particles, which comprises in combination a heat-insulated resonating cavity, with a high-frequency electromagnetic source of energy, a ferrite circulater, a wave guide, an Archimedes screw for the introduction of the plastics material to be pre-expanded, a pump for regulating the feed of polar liquid and a device for extracting the pre-expanded particles. The present invention provides also a process for the pre-expansion of particles of plastic material using said apparatus.