Abstract: The invention relates to high molecular weight (co)polyamides and to a process for the accelerated production of polyamides during melt polycondensation using a combination of aminocaprolactam (ACL) and/or lysine components and polycarboxylic acids and known catalysts and also, if desired, for the accelerated solid-phase post-condensation of the catalyst-containing (co)polyamides and to the polyamides produced by the processes.

Abstract: A gas pressure bonding furnace having a convection shield with (1) monolithic tubular refractory insulation having its upper end surrounding the work receiving hot zone of the furnace and its lower end depending to a cool zone, (2) an impervious tubular metal shell surrounding the tubular insulation and holding it under compression by differential thermal expansion, (3) a cover closing the top of the shell by a gas tight gasket seal and (4) a piston actuated by the gas working pressure to hold the cover closed. In a preferred form, the insulation is cast in the shell and the composition is an alumina cement with embedded alumina balloons.