FIELD: shaping.
SUBSTANCE: invention relates to a technological process for producing foamed thermoplastic microspheres and to an apparatus therefor. The method includes: supplying a suspension of non-foamed thermally foamable thermoplastic microspheres into the heating area using a pump capable of generating a pressure greater than atmospheric in the heating area; heating the microspheres to a temperature greater than the softening temperature thereof, wherein the microspheres are simultaneously put in conditions of pressure high enough to ensure incomplete foaming thereof; thus passing the heated microspheres from the heating area to the foaming area so as to create a pressure drop, resulting in a pressure in the foaming area low enough for foaming microspheres, and removing the foamed microspheres from the foaming area; wherein the foaming area is configured to create a variable counterpressure while using a back-pressure generator located downstream from the foaming area. The apparatus includes: a heating area including an inlet and outlet, a pump located upstream from the heating area and in fluid communication therewith, capable of generating a pressure greater than atmospheric in the heating area; a tool for heating the heating area; a foaming area including an inlet and outlet, wherein the inlet the opening of the foaming area is connected with the outlet of the heating area so as to create a pressure drop to ensure that the foaming area is at a lower pressure than the pressure in the heating area, and a back-pressure generator located downstream from the foaming area and configured to create a variable counterpressure in the foaming area.
EFFECT: invention increases the manufacturability of foamed thermoplastic microspheres.
12 cl, 3 dwg, 4 tbl
