Curing of thick, strongly exothermic-thermosetting resin plaques - by limiting temp. increase by cooling resin surface with nitrogen gas flow than cooling mould by nitrogen gas flow both of which discharge into oven containing mould for recovery

摘要

Thick plaques of thermosetting resin having a strongly exothermic polymerisation reaction are curved by:- putting the resin in a mould (10) and applying a cycle in which the temp. rise includes two levels; at each level the temp. is maintained close to the new level by blowing a cooling fluid gas onto the free surface of the resin than after a delay cooling the mould (10) to a temp. slightly less than the cooling fluid temp.. Also claimed is a prodn. appts. consisting of:- a mould (10) the base (44) of which is fitted with cooling channels; a means (12) of blowing cooling gas partic. nitrogen at about 20 deg. C on top of the resin, a temp. control circuit and an oven (14) to house the mould and blowing system. USE/ADVANTAGE - Use to cure thick, greater than 3.5 mm, strongly exothermic thermoset resins. Allows curing in a mould without excessive temp. in the resin and without degradation.