batt was prepared as in example 1 except the fiber content was staple fill fibers 55 weight percent trevira u2122 type 121 polyethylene terephthalate 1 2 denier 3 8 cm long available from hoechst celanese corp and staple bonding fibers 45 weight percent of the core sheath fiber used in example 1 and the web was crosslapped to form a 20 layer batt in example 6 a batt was prepared as in example 1 except the fiber content was staple fill fibers 55 weight percent fortrel u2122 type 69460 polyethylene terephthalate 0 5 denier 3 8 cm long available from wellman fiber industries florence s c and staple bonding fibers 45 weight percent of the core sheath fiber used in example 1 in example 7 a batt was prepared as in example 1 except the fiber content was staple fill fibers 55 weight percent trevira u2122 type 121 polyethylene terephthalate 0 85 denier 3 8 cm long available from hoechst celanese corp and staple bonding fibers 45 weight percent of the core sheath fiber used in example 1 samples were tested for basis weight bulk density thickness thermal resistance thermal weight efficiency and hand the test results are set forth in table i table i__________________________________________________________________________example 1 2 3 4 5 6 7__________________________________________________________________________fill fiber 75 55 25 55 55 55 55 bonding 25 45 75 45 45 45 45fiber basis 233 240 255 101 383 221 250weight g m sup 2 thickness 10 6 9 5 9 8 3 7 14 4 8 2 14 9 cm bulk 2 2 2 5 2 6 2 7 2 7 2 8 1 7density kg m sup 3 thermal 7 4 7 0 6 9 3 1 10 4 7 6 8 8resistance clo thermal.