Last year Sekisui Voltek, Lawrence, Mass., began producing limited quantities of what is believed to be the highest-density crosslinked polyolefin foam in the world. The company is producing fine-celled XL LDPE and EVA foams of 20 pcf, only one-third that of solid polymer. Three years ago, it reached as high as 18 pcf in producing foams for gaskets, tapes, and other specialty products requiring high strength and compressibility. XLLDPE is typically foamed to densities of 2 to 6 pcf. Volara HD (high-density) foams are 0.01 to 0.08 in. thick and aimed at industrial mountings, gaskets, and medical applications like wound care. Rolls are 55 to 65 in. wide and over 6000 ft long.