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Modern powder coatings were introduced in 1952. They created great interest and much was written about them and much predicted for them. They did indeed find a niche, but they did not deliver quite as had been anticipated and by the early 1960's their star was waning. But one must never discount the impact of advancing technology — particularly when economy, convenience and performance are involved. Novel methods of application, primarily electrostatic spraying to complement the original fluidised bed approach, new formulations, faster curing epoxies and a better understanding of both the virtues and the defects of this method for industrial coating, has brought powder coatings back into their own.

In recent years aluminium has become a very widely used material in the construction industry. Light weight, good corrosion resistance and ease of fabrication lends itself to a whole variety of end uses. Although the tendency for aluminium to oxidise in the atmosphere is itself a form of chemical “protection”, improvements in weather and chemical resistance can be gained from the use of a variety of surface coatings. These coating technologies are typically of the following types: polyvinylidine difluoride, water‐borne electro‐paint, conventional solvent‐based paints, powder coatings and anodising. The two most popular technologies in use today are: TGIC (Triglycidyl isocyanurate)/polyester powder coatings and polyvinylidine difluoride (PVDF) solvent‐based coatings. Coated aluminium has the added competition in the window frame and door frame market from uPVC. Only coated aluminium will be discussed in this paper.

The Federation of Societies for Paint Technology authorised Levinson to do a study on powder coating, electrocoating and radiation. In an article [Journal of Paint Technology, July (1972) p. 37] Levinson describes the advantages and disadvantages of powder coating, the technology involved, the economics of the various systems, the relationship to ecology, the manufacture of powders, the resins which are useful, and future trends.

Over the last few years, the share of powder coatings used for the protection of aluminium extrusions and claddings for architectural uses in competition with conventional liquid paints and as an alternative to anodising has sharply increased. In 1987, about 47 million m2 or 135 thousand tons of aluminium used in outdoor architecture have been powder coated in France, Germany, Italy and United Kingdom. This paper gives a thorough description of the latest developments of the polyester powder coating systems used for aluminium extrusions and claddings in Europe, underlining the criteria of the choice of the weathering resistant powders, the importance of metal pretreatment and of the coating process itself as well as of the quality control in this industry. A comparison with competitive coating technologies is also given.

Powder coatings are well established as a finishing technique in the automotive component market worldwide. These coatings offer benefits such as toughness and chip resistance. As the performance demands on powder coatings have increased then powder has continually risen to the challenge. Flexible coatings are supplied for brake tubing, machinable coatings for engine blocks and a new class of advanced durability powder offering resistance to five years of Florida weathering has recently been introduced. The new class of advanced durability powders offer significant advantages over most paint finishes for exterior durability while retaining all the traditional performances and application advantages of powder coatings.

More articles have been published about powder coating in the last two years than about any other phase of the protective coatings industry. From this almost overwhelming flurry of print, certain factors emerge. The first is that powder coating technology is certainly a valid and useful one. It has established itself as an integral contributor to the achievements of the protective coatings industry and, without doubt, it will be with us for many years to come. Its success is due to its many advantageous factors which have been reviewed many times in the past. Great strides have been made in that a highly versatile group of powders are now available with both thermoset and thermoplastic properties; it is possible to achieve thin coatings; and the savings in terms of effective powder usage have been well‐documented. Where there is overspray, equipment has been evolved for recycling. Stressed most often has been powder coating's contribution to a non‐polluting painting operation. Powder coating, on the other hand, does not solve the energy shortage problem since the coatings must be fused and baked. However, less energy is required than for solvent based coatings simply because the energy requirements associated with solvent removal are eliminated.

POWDER coating technology has provided a means of applying resin coatings to substrates via processing techniques which have two distinct advantages over conventional coating procedures. The first and probably most significant advantage from an ecological standpoint is the elimination of solvent carriers. The absence of solvents eliminates the emission of fumes and vapours thereby providing an environment that is virtually free of pollutants. Safety standards are also improved because the hazard of fire is substantially reduced.

As technology becomes more complex, the need for coatings of specialised functions continues to increase. The electronics industry, for example, makes demands on the coating industry for both conductive and insulation coatings. Highly temperature‐resistant coatings played a key role in the aerospace industry. Fire retardants contribute to consumer safety and coatings for plastics serve a number of protective and decorative functions.

This article will discuss some or our recent findings about the future of powder coatings, and attempt a number of difficult predictions of how, where, and why powder coatings will now grow in this decade on a worldwide scale. In so doing, we will try to clarify the technical and marketing restraints to powder coating growth. This growth, of course, is now guaranteed. Ours has been the more difficult task of quantifying that growth and putting powder coating technology into its proper perspective.

Many of you may already be familiar with the term ‘powder coating’. For those of you who are not, I would like to describe the term briefly. Powder coating is a relatively new process by which dry plastic powders are applied to a clean metal surface. After application, the coated object is heated, fusing the powder to form a smooth, tough coating. Available today are many plastic powders offering a wide range of properties and colours. These powders are fully formulated and are free‐flowing ready for application to metal. Previous coatings for such items have been applied from solution. The dry plastic powders are normally higher molecular weight polymers than those used in solution: because of this, the coatings produced have greatly increased durability, toughness and abrasion resistance.