14.1 Introduction

Rubber is used in corrosion-proof linings, more than any other material, because of its proven superiority in such applications. Fertilizer, steel plants, chemical, caustic soda, paper, ore, mining, and pharmaceutical industries use rubber linings in process equipment where corrosive media must be handled. Synthetic and natural rubbers form a unique class of high polymers having worldwide acceptance in combating corrosion. One of the most important characteristics of natural and man-made rubbers is their remarkable resistance against corrosive chemicals, fumes, acids, and alkaline and salt solutions handled in chemical plants and equipments such as storage and reaction tanks, ducts, vessels, pipings, and so on. In the absence of anticorrosive rubber linings, corrosion would be so extensive that most products of modern technology could not exist.

The compound formulation technique for producing a useful end product for application in anticorrosion linings and coatings calls for thorough knowledge of rubbers and the chemicals which are admixed with them. The compounds are calendered to form a uniform sheet of thickness ranging from 2 to 10 mm, as per requirements. The most commonly adopted thickness is 5 mm for corrosion resistance and 10 mm for abrasion resistance. The metal surface is cleaned by sand/shot blasting, applied with a coat of adhesive and then the rubber sheets are laid/lined over the coated surface. The lined equipment is then cured/vulcanized in an autoclave under specified temperature and pressure conditions. Various curing methods are adopted such as autoclave curing, hot water curing, open steam curing, and...