THE SUCCESS OF REINFORCED POLYESTER RESINS FOR COMBATING CORROSION IN PROCESS PLANT

Millions of pounds are spent every year in the fight against corrosion by users of process plant. Corrosion often necessitates frequent maintenance or replacement of equipment and causes costly production losses. In many instances these problems can be reduced by the use of metal alloys, but even stainless steel, the most commonly used corrosion resistant alloy, is expensive, and if more specialised metals are required the cost of preventing corrosion becomes even higher. Because of this situation reinforced polyester resins are now being used very successfully on a rapidly increasing scale throughout the world in a wide range of industries handling corrosive materials. Probably the best known resins for high corrosion resistance are the bisphenol polyesters, some of which have now been used for constructing process plant for around 20 years. For example Figure 1 shows a tank of reinforced ‘ATLAC’ resin installed by Monsanto Company in America in 1954 to store acid chrome sulphate liquors containing about 20% sulphuric acid and residual amounts of organics at temperatures up to 55°C. Wooden staves and steel hoops were placed round the tank as a precaution, because at that time little was known about the long term performance of glass fibre reinforced polyester. However, the tank was still giving excellent service 17 years later.