Introduction to paints and coatings

Before we focus on chemical vapor deposition let us briefly mention other methods for thin film deposition. Films with thicknesses from 1 /zm to several 10 /zm play a fundamental role in everyday life, for example as paints and coatings. Processes during film formation are complex and a discussion would exceed the scope of this book. Introductions are Refs. [407,408],... 

The present effort attempts to facilitate this latter process by presenting in a single volume, technical discussions on various aspects of plastics of relevance to the environment. The first section of the book is intended to be an introduction to the key subject matter of plastics and environment, for those needing such an introduction. The second section explores several major applications of plastics with environmental implications packaging, paints and coatings, textiles, and agricultural film use. The next section explores the behavior of plastics in some... 

Various strategies are employed to prevent corrosion. The use of paint as a protective coating is described in our chapter introduction. A metal surface can also be protected by coating it with a thin film of a second metal. When the second metal is easier to oxidize than the first, the process is galvanization. Objects made of iron, including automobile bodies and steel girders, are dipped in molten zinc to provide sacrificial coatings. If a scratch penetrates the zinc film, the iron is still protected because zinc oxidizes preferentially ... 

A most important development in the modem paint and varnish industry has been the introduction of synthetic resins as replacements for natural resins in the manufacture of varnishes and enamels. By using synthetic resins it has been possible to produce a variety of coatings that, in many cases, have important points of superiority over any of those compounded from natural resins. The synthetic vehicles are particularly distinguished by their hardness and durability and their high degree of resistance to the action of water, alkalies, and other chemical agents. 

Chlorinated phenoxy acids are used extensively as herbicides in agriculmre, as algaecides in paints, and as coating agents. These are the main sources of their introduction in to the aquatic system. Their removal efficiency using... 

Less than 50 years ago, virtually all paint and other surface coating formulations were based on hydrocarbon solvents as the liquid phase. Following advances made in emulsion or latex polymer chemistry, resin systems became available which had the necessary properties of mechanical strength, durability and cost effectiveness such that today, emulsion paint dominates the decorative coatings area. This trend was assisted by the introduction of legislation which discouraged and, in some cases, prohibited the use of formulations which resulted in VOC (volatile organic carbon) emission to atmosphere. 

Ethylene-propylene rubbers (EP) have low total surface energies with small polar components. As would be expected, the adhesion of paints and adhesives to untreated EP is poor. To achieve good adhesion to EP, the introduction of suitable functional groups is necessary unless a diffusion mechanism can operate. Bragole [26] found that UV treatment of EPDM coated with a thin layer of benzophenone resulted in large increases in the adhesion of acrylic, epoxy and urethane paints to the polymer. 

The introduction of rfpowered sources has extended the capability of GD-OES to non-conductors, and several rf sources of different design have become commercially available. This is of the greatest importance for surface and depth-profile analysis, because there exists a multitude of technically and industrially important non-conductive coating materials (e. g. painted coatings and glasses) which are extremely difficult to analyze by any other technique. 

Since the previous edition was written, the main development has been the introduction of a range of zinc alloy coatings designed to give increased corrosion resistance and sometimes with additional advantages such as increased formability and retention of paint adhesion with a wider range of paints. 

Safety No year goes by without some widely used chemical being declared suspect on toxicity grounds. The paint industry has responded rapidly to eliminate toxic chemicals from coatings or to show how they can be used safely in an industrial environment. Examples are the elimination of specific ether-alcohol solvents and the introduction of air-fed hoods for spraying isocyanates. Of particular interest in corrosion prevention is the current pressure to eliminate chromate pigments. Currently there are no equally effective alternatives and the emphasis has had to be on safe usage. The search for replacements continues. 

Few industries have been as affected by the restructurings of the past ten years as the paint industry. The extension of markets worldwide owing to the multiplication abroad of client factories of this industry, the technological revolutions brought about by the introduction of electrophoresis, of water-based lacquers, and of powder coatings had the twin effect of pushing the chemical leaders to expand worldwide in this area and to lead those paint companies that were still independent to sell out for want of the funds needed to develop... 

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