Cellular resinous materials and processes of making the same

Claim 1

THE PROCESS OF MOLDING WHICH COMPRISES THE STEPS OF SUBSTANTIALLY FILLING MOLD WITH DENSE GRANULES OF A RESINOUS MATERAIL COMPRISING A THERMOSETTING RESINOUS CONDENSATION PRODUCT OF AN ALDEHYDE AND A PHENOL, A BUTADIENE ACRYLONITRILE COPOLYMER RUBBER, AN ELASTOMERIC COMPOUND WHICH IS NOT REACTIVE WITH THE PHENOL ALDEHYDE RESIN, AND A BLOWING AGENT WITHIN THE GRANULES OF RESINOUS MATERIAL, HEATING THE GRANULES TO SOFTEN THE RESINOUS MATERIAL AND TO CAUSE THE BLOWING AGENT TO EXPAND THE GRANULES TO ESTABLISH MOLDING PRESSURE AND TO FORCE THE SURFACES OF THE EXPANDED GRANULES INTO CONTACT WITH THE SURFACES OF ADJACENT GRANULES AND TO SINTER TOGETHER THE CONTACTING SURFACE PORTIONS OF THE GRANULES INTO A CONTINUOUS NETWORK OF RELATIVELY THICK MEMBRANCES OF RESINOUS MATERIAL DEFINING CELLS, THE EXPANDED RESINOUS MATERIAL OF THE INTERIOR OF THE GRANULES FORMING THINNER MEMBRANES SUBDIVIDING SAID CELLS, AND CONTINUING THE HEATING TO COMPLETE THE REACTION BETWEEN THE PHENOL ALDEHYDE RESIN AND THE COPOLYMER.