Abstract: An electrically conductive polyurethane foam product is prepared by the in situ combination of polyurethane-forming reactants and an effective amount of a charge transfer agent selected from the group consisting of tetracyanoethylene (TCNE), picric acid and analogs thereof, for lowering electrical resistance of the foam product to less than 1.times.10.sup.12 ohms. In a preferred embodiment, the conductive foam product is reticulated to a void volume of more than 80% after completion of the foam forming reaction.

Abstract: An electrically conductive polyurethane foam product is prepared by the in situ combination of polyurethane-forming reactants and an effective amount of a charge transfer agent selected from the group consisting of tetracyanoethylene (TCNE), picric acid and analogs thereof, for lowering electrical resistance of the foam product to less than 1.times.10.sup.12 ohms. In a preferred embodiment, the conductive foam product is reticulated to a void volume of more than 80% after completion of the foam forming reaction.

Abstract: A supporting bed for supporting a stack of sheet material in a cutting machine of the type retaining the material by means of a vacuum applied from below the supporting bed is manufactured from a composite structure of starting material including individual layers of reticulated foam material separated by at least one layer of a hot melt adhesive web. The composite structure is compressed under heat and pressure so as to be permanently reduced to approximately 10-35% of its initial thickness. The degree of compression, the temperature and compression time, and the porosity of the retriculated polyurethane foam starting material are selected to provide particular airflow and firmness characteristics for the finished supporting bed.

Abstract: A supporting bed for supporting a stack of sheet material in a cutting machine of the type retaining the material by means of a vacuum applied from below the supporting bed is manufactured from a sheet of reticulated polyurethane foam material which has been compressed under heat and pressure so as to be permanently reduced to approximately 10-35% of its initial thickness. The degree of compression, the temperature and compression time, and the porosity of the reticulated polyurethane foam starting material are selected to provide particular airflow and firmness characteristics for the finished supporting bed. In a preferred embodiment of the invention, the starting material is a reticulated grafted polyether foam having a porosity of 30 pores per inch and a sheet thickness of 5 inches. The sheet of material is compressed to a thickness of one inch and retained under pressure for 10 minutes at a temperature of about 400.degree. F.

Abstract: A supporting bed for supporting a stack of sheet material in a cutting machine of the type retaining the material by means of a vacuum applied from below the supporting bed is manufactured from a sheet of reticulated polyurethane foam material which has been compressed under heat and pressure so as to be permanently reduced to approximtely 10-35% of its initial thickness. The degree of compression, the temperature and compression time, and the porosity of the reticulated polyurethane foam starting material are selected to provide particular airflow and firmness characteristics for the finished supporting bed. In a preferred embodiment of the invention, the starting material is a reticulated grafted polyether foam having a porosity of 30 pores per inch and a sheet thickness of 5 inches. The sheet of material is compressed to a thickness of one inch and retained under pressure for 10 minutes at a temperature of about 400.degree. F.

Abstract: A support surface is formed into a trough, a liquid polymer which expands on reaction is dispensed onto the support surface, and the support surface is inclined to cause flow of the polymer to a region in which the polymer expands. The polymer is introduced onto a supporting liquid which supports the polymer in a zone which is substantially coextensive with at least a major portion of the expansion region. The supporting liquid has a specific gravity higher than that of the polymer, whereby the polymer floats on and advances across the supporting liquid in the form of an expanding mass having left and right sides, a flat bottom and a top which slopes upwardly in the direction of the advance. Conveyors support the expanding mass at the respective left and right sides thereof. The conveyors are submerged in the liquid at their upstream ends, and the direction of advance of their polymer-supporting active surfaces is substantially parallel to the sloping top of the polymeric bun as it expands.