Urea!-formaldehyde! plastic foam - mfd. in first blowing stage and second catalytic hardening stage

摘要

Plastic foam is produced from urea formaldehyde resin and foaming agent in two stages. Water, resin and foaming agent are mixed with compressed air long enough to form a homogenised foam of 15 to 20 times greater volume. The hardening catalyst is then introduced under pressure together with compressed air at a rate needed to raise the foam volume to 25-40 times the original figure. This raises the degree of homogenisation of the foam structure and increases the throughput of the whole plant. It produces foam with >=25 times the original volume.