Materials Performance

NOV 2014

Materials Performance is the world's most widely circulated magazine dedicated to corrosion prevention and control. MP provides information about the latest corrosion control technologies and practical applications for every industry and environment.

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Page 42 of 92

40 NOVEMBER 2014 MATERIALS PERFORMANCE NACE INTERNATIONAL: VOL. 53, NO. 11 A Coating manufacturers go to great lengths to produce quality products and provide sound technical recom- mendations for individual projects. This two-part article discusses several case histories where the coating manu- facturers, because of their errors, caused a coating failure. Among the topics discussed are quality control methods, raw material availability and supply issues, color matching and batch controls, inventory management and product shelf life, excess or aged product rework, and botched recom- mendations. The discussion began in Part 1 (October 2014 MP). As a 30-year veteran of th e coatings industry, I have seen just about everything that could go wrong on a project. These problems have been caused by any number of factors, including contractor error, bad specifications, improper product selection, Mother Nature, etc. This article discusses a few incidents where the coating manufac- turer was the primary cause of a problem. Coating Reformulation on the Fly The raw materials used in protective coatings do not remain constant, and are occasionally changed for a number of rea- sons. Manufacturers and vendors are con- tinually looking to consolidate raw materi- als to minimize inventory and gain better purchasing power for high er v olum es. Regulations sometimes force change and raw material vendors are required to refor- mulate their products. Good examples of regulatory impacts are the volatile organic c o m p o u n d ( V O C ) r u l e s , w h i c h h av e become more restrictive in the last 20+ years. Additionally, some raw materials are discontinued by vendors for economic rea- sons, such as a lack of sufficient volume of sales and profitability to justify their con- tinued sale. W h en th e se raw m at eri al chan ge s occur, manufacturers are sometimes con- fronted with the challenge of quickly refor- mulating their products to meet market demand. While a great effort is made by both the raw material supplier and the coating manufacturer to fully evaluate new substitute raw materials, formulation mis- takes sometimes occur. Some of the common substitute raw materials used in recent years to meet regional regulations have b een " VO C- exempt" solvents. These exempt solvents meet the regulations for VOC contribution in a coating formula, but do not always yield the same performance in finished products. Depending on the formula, these exempt solvents do not yield the same wet- ting characteristics, thixotropic develop- ment, sag resistance, etc. The negative ef fects of substitute material s are not always realized in the lab, but sometimes app e a r w h en th e pro du c t s a re b e i n g applied in the field under "real world" con- ditions. An epoxy coating that had been used for many years as an anticorrosive interme- diate coat for tank exteriors in Southern California is one example of a simple sol- vent change in a formula causing a major problem on a project. Prior to the formula- Coating Failures—A Coating Supplier's Perspective—Part 2 Russell spotten, Corrosion Probe, Inc., Centerbrook, Connecticut COATINGS & LININGS

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