The beginnings of coil coating
Coil coating first appeared in the 1940s. Its roots can, however, be traced back to the architectural movements of the late nineteenth and early twentieth centuries.
Steel started to be used in construction and soon steel structures were painted to beautify and afford distinction. In the years to follow, techniques and paints were developed enabling metal pre-coating to become established.
Art and industry
At the start of the twentieth century, art, architecture and industry came together, budding architects integrating metal forming techniques with the shapes and concepts of traditional crafts. This new approach was well received by the construction industry and soon became the norm. New techniques and materials were sought and it was within this frenzy that the German school, Bauhaus, was founded, out of which some of the greatest forerunners of modern architecture were to emerge: Le Corbusier, J.J.P. Oud, Gropius, Mies van der Rohe, Frank Lloyd Wright…
Was it the influence of works presented at the modern architecture exhibition in New York in 1932 that lead to some astounding innovatory spin-offs? Was it a need to satisfy an American craze for art during this period? Or the carrying out of a great architectural program of bridges and highways, of which Le Corbusier said in front of the George Washington Bridge on its completion in 1931: "Cable and steel, it shines in the sky like a blessed, upside down arc. … Its structure is so pure, so solid, so precise that here we finally see metal architecture beam with happiness."
In 1940, it took 12 hours to produce 1 tonne of painted metal: today, 500 tonnes can be produced in this time.
As steel took on an increasingly more important role in construction history, coatings were developed in one form or another, whether for protection, for decoration or both. As a result, the very first continuous coil coating lines appeared at the beginning of the 1940s in the United States; the process was used to coat steel louvered shutters measuring 50 mm wide and 0.3 mm thick. Production speed was 12 meters per minute and required some 12 hours to produce 1 tonne of coated metal.
The industrialization of construction
Coil coating really took off in the United States in the 1950s. Both architecture and the electrical household goods industry now looked to these new combinations of painted steel or aluminium. During the 1960s, lines reached speeds of 75m/min with widths of 1.50m. In 1962, production reached 460,000 tonnes (290,000 tonnes of steel and 170,000 tonnes of aluminium) and the following year, two coat lines were introduced for galvanised steel.
By 1966, the United States had 90 modern coil coating lines and produced more than 500,000 tonnes per year. At the end of the millennium, there were some 180 lines (steel and aluminium combined) which produced 4.2 million tonnes of coated metal.
The European lines
The real turning point for coil coating in Europe occurred between 1960 and 1965 when the first lines appeared in Sweden, Germany, Great Britain, Belgium, Italy, Switzerland and France. Outlets for the pre-painting industry were targeted. In 1965, for example, a producer of pre-painted aluminium referred to the following markets in its commercial literature: construction (weather-boarding or siding, roofing, curtain walls), building accessories (metal fastenings, sliding shutters, sun shades, canopies, louvered shutters…), interior applications (false ceilings, partitions…), the transport industry (caravans, buses…), miscellaneous products (casing for household products, radios, television, camping equipment, games, electrical appliances,…).
All the important types of paint already used in industry - organosols, vinyls, alkyds, acrylics and epoxies - were now employed in coil coating. Water-based products were developed in Sweden but implementation has been minimal for following three reasons:
- they were more difficult to use than solvent-based products;
- they were expensive;
- they were of little interest to the coil coating lines equipped with solvent incinerators.
Achievements
The first pre-painted siding was bright red coated aluminium and used for the walls of the exhibition buildings at the Porte de Versailles, Paris, in 1964.
By 1965, pre-painted aluminium was widely used for facing panels, the false ceilings of the swimming pools and canopies of filling (gas) stations, prefabricated villas, etc.
During this time, there was much innovation, for example one producer manufactured pre-coated aluminium which was then embossed so as to imitate the earthenware tiles used around sinks. Pre-painted steel manufacturers for their part mainly specialised in the production of siding for buildings.
The players
By 1966, Europe had 14 lines.
In 1967, the European Coil Coating Association (ECCA) was founded in Brussels, Belgium. This scientific-based association aimed to “research and promote the production and the use of coils and/or sheet metal pre-coated with organic matter”. Its 80 founder members included steel and aluminium coil coaters, suppliers (surface treatment, paints, films, strippable coatings) and line equipment constructors.
Today, ECCA membership covers countries round the world and includes 70 coil coaters, 48 paint manufacturers, 7 distributors and 75 other members, such as suppliers of film, raw materials or equipment.
Link: ECCA website.