Like other popular synthetic insulations—Polarguard, Thinsulate, etc.—PrimaLoft manages moisture well and will absorb at most roughly 1 percent of its weight in water. Because of this, it dries very quickly and still retains much of its insulating ability even when wet. PrimaLoft claims to absorb even less water than its competitors, though in my opinion there's really not that much difference between something that absorbs 0.33 percent instead of 1 percent, or even 1 percent instead of 3 percent.
What distinguishes PrimaLoft, however, are the ultrafine, tiny-diameter fibers that make up the insulation. This makes it lighter and more compressible than other synthetics. In fact, Primaloft was first created in the 1980s when the U.S. Army contracted with Albany International of New York to develop a synthetic alternative to down.
These micro-fibers also give PrimaLoft a much softer drape. Drape refers to a material's ability to shape itself to whatever it surrounds or lies on top of. Stiffer materials (less drape) will leave small gaps between itself and the covered object. Softer fabrics (more drape) will fall more or less flush with the object and increase overall warmth.
A variety of different Primaloft versions exist—PrimaLoft Infinity, PrimaLoft One, PrimaLoft Sport—but the one that has caught my attention lately is PrimaLoft Eco. According to the marketing literature, "Eco insulation technology combines 50% recycled material with PrimaLoft virgin fibers to create a high loft, thermally efficient insulation."
They don't specify exactly what they mean by recycled material, which leads me to believe that it is probably post-industrial waste (eg. leftover clippings from the factory floor) rather than post-consumer waste (like old soda bottles). Nevertheless, any version of recycled material is better than none.
Several gear companies are starting to incorporate PrimaLoft Eco into their 2009/10 line-ups. Here are some of the more drool-worthy jackets I'm eyeing for the winter season.
Mountain Hardwear Compressor Jacket and Pants
Outdoor Research Fraction Hoody
REI Women's Nevis Jacket
Patagonia Winter Sun Jacket
"Equipped" is an AMC Outdoors blog, written by Matt Heid.