Glass foam prodn. from glass powder and carbonaceous foaming agent - with hydrogenation and dehydrogenation catalysts

摘要

Glass foam prodn. from a mixt. of a glass powder and a carbon-contg. foaming agent evolving a gas on heating is improved by adding such an amt. of a hydrogenating and/or dehydrogenating catalyst that the gas evolution begins first when the glass m.pt. is reached, and ceases when the temp. drops below the m.pt. The pref. foaming agent is carbon black (particle size 200 mu). The catalysts promote a rapid establishment of an equilibrium between the starting foaming materials, i.e. carbon black and water vapour, and their reaction products, namely, CO, H2, CO2. As a result, foam contg. closed cells of uniform size and even distribution is produced at a lower cost than by known methods. Suitable hydrogenation catalysts include metals of subgroups VI-VIII or their oxides. Pref. are Ni or NiO (=0.1 wt.%) and MnO2 (=1 wt.%). The pref. dehydrogenation catalyst is BPO4 (=1 wt.%).