Compounding Neoprene for tank lining application

Red lead is an ingredient generally used in all Neoprene compounds for tank linings for good water and chemical resistance. But it should not be used in compounds of Neoprene designed for contact with food or potable water. Tubes or pipes for conveying potable water are made of ethylene-propylene diene terpolymer (EPDM) rubbers. 

While calendering the Neoprene stock it must be prewarmed uniformly before being fed into the calender rolls. Stock temperature will change as the quantity of the stock at the nip varies. This causes fluctuation in viscosity of the stock and in roll pressure leading to rough sheet with differing thickness. Roll temperature in calendering must be accurately 

Air blisters can be avoided easily in thinner sheets that can be plied up to the required thickness, rather than one step calendering of a thicker sheet that induce formation of air blisters during calendering. 

The lined tanks are cured in situ to achieve good adhesion with metal. Neoprene linings can be cured with air, steam or hot water. Many curing cycles for Neoprene are adopted depending upon the compound type, size and shape of the equipment. 

Typical curing cycles for Neoprene linings are given in Table 6.1. 

---