| abstract |
A FIREPROOF CARPET UNDERLAY IS PROVIDED WHICH HAS IMPROVED LOAD-DEFLECTION CHARACTERISTICS AND YET CAN BE MADE AT A FRACTION OF THE COAT OF CONVENTIONAL CARPET UNDERLAY. THE UNDERLAY IS MADE FROM POLYURETHANE FOAM SCRAP OF LOW DENSITY (I.E., 1 TO 3 POUNDS PER CUBIC FOOT) AND TWO THIN SHEETS OF INEXPENSVE PLASTIC MATERIAL, SUCH AS POLYETHYLENE OR POLYVINYL CHLORIDE COATED WITH A VINYLIDENE CHLORIDE POLYMER. THE UNDERLAY HAS A MULTIPLICITY OF REGULARLY SPACED CIRCULAR OR POLYGONAL POCKETS SAND- WICHED BETWEEN THE TWO PLASTIC SHEETS AND CONTAINING A SUBSTANTIAL AMOUNT OF AIR AND A FIRE-RETARDANE LIQUID, SUCH AS WATER, IN A MAJOR AMOUNT BY WEIGHT SUFFICIENT FOR FIREPROOFING. EACH POCKET FUNCTIONS AS AN AIR CUSHION AND TAKES UP A SUBSTANTIAL PROPORTION OF THE LOAD (I.E., 20 TO 50 PERCENT) BY COMPRESSION OF AIR, THE BALANCE BEING TAKEN BY COMPRESSION OF THE FOAM. |