Polar Fleece

Polar fleece is produced on a circular knitting machine using polyester yarn, then the knit face is passed through a napper — the same process as flannel — to raise a thick, lofted pile from the surface. The pile creates thousands of tiny air pockets that provide excellent insulation at very low weight: 200g/m² fleece provides warmth comparable to a wool fabric at twice the weight. Unlike down insulation, fleece retains insulating properties when wet (polyester absorbs negligible moisture) and dries rapidly, making it the preferred mid-layer in active outdoor applications. Fleece does not block wind — a tightly woven shell layer is required for wind resistance — but modern bonded fleece constructions laminate a woven shell directly to the fleece backing. Most commercial polar fleece today is made from recycled PET bottles (rPET); quality brands specify post-consumer recycled content percentages. Fleece weights are typically classified as 100 (lightweight), 200 (mid-weight), and 300 (heavyweight) g/m².