More people must be wearing thermal underwear because of global warming.
Lots of uses.
How is propylene used?
http://www.shell.com/global/products-services/solutions-for-businesses/chemicals/products/lower-olefins/propylene.html
The materials that are derived from propylene include: polypropylene; acrylonitrile (which is converted to acrylic fibres and coatings); propylene oxide (which then goes into polyurethane resins and other chemicals); oxo alcohols (which are used in PVC plasticisers and coatings); cumene (which is ultimately used to make epoxy resins and polycarbonate); and isopropyl alcohol (which is used as a solvent).
As a result, propylene is a key component of countless end use products. Examples include automobile headlights, taillights, disk brake pads and bumpers; carpets; CDs and optical disks; clear film food wrap; eyeglasses; flexible foams used in bedding and furniture; rigid foam insulation; impact-resistant and bullet-proof windows; moulded plastic goods such as buckets, food containers, kitchen utensils and wastebaskets; nitrile rubber hoses, seals and gaskets; paints and protective coatings; grocery bags; synthetic fibres for blankets, sweaters, socks and fleeces; water cooler bottles; and wood products such as plywood, oriented strand board and laminates.