PVC -p- Polyvinyl chloride. A flexible form of PVC due to the addition of high molecular weight plasticizers, which can be heat or solvent welded (depending upon the product). PVC-p-based membranes are generally not suitable for direct contact with bitumen unless a suitable weight of fleece backing is incorporated to separate the two.
FPO - Flexible Polyolefin. FPO is a large family of heat-weldable polyolefin based upon polyethylene or polypropylene. Preparation of the lap prior to welding may be required. FPO-based membranes are generally suitable for direct contact with aged bitumen.
TPE - Thermoplastic Polyolefin Elastomer. A particular group of polyolefins with the basic properties of elastomers but which can be processed as thermoplasts. They exhibit a high resistance to UV /Ozone exposure and do not absorb moisture. Laps are heat welded without production of fumes or smoke. The wide temperature range for welding enables secure welding of seams in differing climatic conditions.
CPE - Chlorinated polyethylene. Polyethylene is made flexible by chlorination and can be heat or solvent welded. Generally, CPE is compatible with bitumen.
EPDM - Ethylene Propylene Diene Terpolymer. EPDM is a naturally flexible material to which carbon black is added for stability. Jointing is normally carried out with tape bonding using a special primer but adhesives can also be used. EPDM is compatible with bitumen. Generally FPO based membranes can be recycled back into themselves or into another product.
PIB - Polyisobutylene. PIB incorporates carbon black to provide good physical properties. PIB products available on the UK market are generally solvent welded using tape systems. and are compatible with bitumen.