GB1279695A - Process for the production of granulated moulding powder - Google Patents

Abstract

1,279,695 Granulating moulding powders PERSTOP AB 27 Nov 1969 58109/69 Heading B5A [Also in Division C3] Moulding powder e.g. melamine or urea resin containing a cellulose filler, is granulated in a container 2 by intermittently introducing a pulse of pressurized air, of 0À5 to 5À0 seconds duration and at intervals of 0À5 to 10 seconds, through an inlet 4 to expand the powder into a turbulent cloud into which granulated liquid e.g. water, is simultaneously sprayed through a nozzle 6. The powder coheres upon settling after the pulses, and this effect may be enhanced by vibrators arranged at the sides of the container 2. The container 2 is provided with a filter 7 and cap 8, with an inlet 3 for powder, and an outlet 5 through which the granules are discharged after drying by warm air introduced into the container 2. The powder may be pre-blended with pigments, catalysts or lubricant, or alternatively these may be added by nozzles or jets within the container, which may be separate from or combined with the pressure air inlet 4, and mixed with the moulding powder prior to the granulating step by introducing pressure air pulses in the absence of the granulating liquid spray. After granulating, the drying, either separately from the container or by introducing warm air thereinto, may be assisted by the preceding introduction to the container of further dry powder which is mixed with the granules by air pulses.