Specific Thermoplastic Sheet Lining Materials

Thermoplastic sheet linings are used more extensively than any other type of lining. Table 3.1 lists the most common thermoplasts used as linings. These materials are used to line piping as well as vessels. They may be installed as a loose lining or as a bonded lining. 

Techniques have been developed to overcome the problem of adhesion, making use of an intermediate bond. One approach is to heat the thermoplastic sheet, then impress into one smface a fiber cloth or nonwoven web. This provides half of the bond. Bonding to the metal surface is accomplished by the use of an epoxy adhesive that wiU bond to both the fiber and the metal. 

Welding techniques for joining the plastic sheets are critical. Each weld must be continuous, leak tight, and mechanically strong. Poor welding is a common cause of lining failure. 

Chlorinated polyvinyl chloride (CPVC) Polyvinylidene chloride (Saran) Polyvinylidene fluoride (PVDF) Polypropylene (PP) 

Ethylene tetrafluoroethylene (ETFE) Ethylene chlorotrifluoroethylene (ECTFE) 

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Extrusion is a polymer conversion operation in which a solid thermoplastic material is melted or softened, forced through an orifice (die) of the desired cross section, and cooled. The process is used for compounding plastics and for the production of tubes, pipes, sheet, film, wire coating, and profiles. All extrusion lines include a melt pump called an extruder, but other equipment is specific to the particular process. Although there are many types of extruders, - the most... 

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