100% Polypropylene - History and Uses
100% Polypropylene underwear has been around for quite some time. Polypropylene was developed in the 1950's. When it was realized that polypro absorbed very little water and retained heat extremely well, it was spun into a thread for use in thermal underwear. Polypropylene has been a very popular performance thermal ever since. It has become a staple for many outdoor industries where the user is exposed to cold wet climates. Cruise liners traveling through the Arctic or Antarctic request that travelers wear polypropylene thermal underwear as a base layer because of its' ability to retain heat better than any other fabric.
U.S. Navy and Coast Guard wear 100% Polypropylene Thermal Underwear
Polypropylene is also very light weight. Available in a thick fleece knit, 100% polypropylene thermal underwear only weighs a fraction of what cotton thermals with the same temperature rating would weigh. One unique and highly desirable feature of 100% polypropylene is the ability to retain heat even when it gets wet. I have a friend that has run river rafting tours on the Colorado River where it winds through The Grand Canyon. One problem river guides have faced over the years is hypothermia due to constant exposure to the cold river water. My friend says he wears polypropylene thermal underwear as a base layer because it is excellent at keeping you warm in cold water. Instead of the cold water sucking the heat away from your body, the polypropylene insulates you and keeps your body's natural warmth next to your skin.
Polypropylene Thermal Underwear Mandated for Navy and Coast Guard
This leads us to the title of this article. All of the properties I've mentioned so far make 100% polypropylene ideal for the U.S. Navy and the U.S. Coast Guard. Dive and rescue teams that will be entering the cold ocean waters are required to wear a base layer of 100% polypropylene underwear underneath their dry suits. OuterSports has a contract with the U.S. Government to sell polypropylene thermal underwear in bulk to The U.S. Armed Forces. The U.S. Coast Guard and U.S. Navy typically has Outersports supply them with the high quality Coldpruf 100% Polypropylene Thermals. There are many different brands you'll find polypro thermals in. But the Coldpruf brand has a much softer hand so it feels great worn next to your skin. OuterSports also carries 100% polypropylene thermal underwear in a thick two layer fleece. This is used as part of the Extreme Cold Weather Clothing System or ECWCS by all of the U.S. Armed forces. Like its' name infers, the thick fleece polypro part of ECWCS is great for extreme cold. The first rule of thermal insulation is that the more air a fabric is able to trap the better it will insulate and the warmer you will be. Polypropylene in fleece form traps more air while the fabric itself retains more body heat than any other fabric. I love to wear the fleece polypropylene thermals when I go out snowmobiling on colder days so I don't have to worry about getting cold.