Polybutylene (PB) - This material is also known as Polybutene-1 (PB-1) and it is a member of the polyolefin family of thermoplastics. Polybutylene is produced by polymerizing butene-1 using Zeigler-Natta catalysts which produce a unique isotactic, semi-crystalline polymer that is ideally suited for applications requiring high strength, flexibility, and heat resistance. This material also provides a higher level of creep resistance compared with other polyolefins and it displays an elevated level of chemical and flammability resistance. Polybutylene can be processed by injection or extrusion molding. Its primary use has been for hot and cold pressurized water pipe systems.