Abstract: An improved process for incorporating glass fibers into a thermoplastic synthetic resin wherein the glass fibers are continuously mixed with a molten thermoplastic synthetic resin and the resulting mixture is shaped into a desired article, involves preheating the glass fibers to a temperature not more than the melting point of the synthetic resin, feeding the preheated glass fibers and the molten synthetic resin separately to a premixing chamber, intermixing the resin and fibers within the chamber and thereafter introducing the resultant premix continously and directly into a two-stage degasifying screw-type extruder for effecting further homogenization of the premix and for extruding the desired article. The two-stage degasifying screw-type extruder used for carrying out this process is provided with a screw having a constant screw pitch in the two stages and in each stage with a low pressure zone and a high pressure zone in succession.

Abstract: An apparatus for the continuous manufacture of filaments from polyvinylidene fluoride includes a screw extruder with a single-spindle screw surrounded by a coaxial barrel with a feed zone, a compression zone, a metering zone, and a mixing head zone for the plasticizing of the polyvinyldene fluoride and with a die outlet tool for shaping the filaments. The compression ratio of the screw is 1:1.2 to 1:2.5, and the screw is provided with single-flight and double-flight sections of identical pitch in alternating succession in the region of the compression zone. The mixing head zone is fashioned as alternatingly successive mixing zones and shear zones, of which there are provided, respectively, two to four zones and preferably three zones.

Abstract: A process for the production of monofilaments of polyvinylidene fluoride is disclosed wherein polyvinylidene fluoride is plasticized in an extruder and fed to an extrusion die and passed through an extrusion nozzle orifice to enter a liquid cooling medium having a thermal conductivity of under 0.4 W/m .degree.K., a viscosity at 100.degree. C. of over 0.5 cp and a density at 100.degree. C. of over 1.1 g/cm.sup.3. Extusion is performed by passing the plasticized polyvinylidene fluoride over separate extrusion zones such as by passing the polyvinylidene fluoride over a first extrusion zone maintained at a first extrusion temperature and thereafter passing the polyvinylidene fluoride through a second extrusion zone maintained at a temperature of 10 to 30 percent higher than the preceeding extrusion zone. An apparatus for carrying out the process is also described.