Thermal insulator comprised of split and opened fibers and method for making same

Claim 1

A synthetic fiber batt thermal insulator material comprising an assembly of individual parent fibers which have diameters in the range of from 9 to 25 microns and provide support for a network of many fibrils, said fibrils having been split away or fibrillated from individual parent fibers and being small in cross-sectional dimension relative to the parent fibers, said batt having the following characteristics: a density of less than 1.0, typically about 0.5 lb/cu ft; an apparent thermal conductivity measured by the plate-to-plate method according to ASTM C518 with heat flow down of less than 0.5 Btu-in/hr-ft 2 -°F.; in the dry state, under a compressive stress of 5 lb/square inch, a compressive strain of at least 90% and a long-term compressive recovery of at least 85% after removal of this stress as determined by the test method of Section 4.3.2 of U.S. Military Specification MIL-B-41826E modified by use of a lower pressure at which initial thickness and recovered-to-thickness are measured; zero gauge length condition: 4.02 g sample; 2.00 inches; 0.3 lb/ft 3 ; nominally zero load.