Paint/painting waterborne paints

Thus, numerous low-emission paints have been developed, including high-solids paints, waterborne paints, aqueous dispersions for industrial use, powder coatings, and radiation-curing coatings. At the forefront in adopting these environmentally friendly products is heavy industry, in particular the automobile and household appliance industries. Medium-sized and smaller businesses will profit from this experience, adapting it for their own needs. 

Viscometers are being increasingly used for accurate measurements on modern industrial paints, especially waterborne paints. Rotating viscometers with a concentric cylindrical geometry (Searle system. Fig. 9.1) are advantageous for paints. Precise thermostatic control is easily achieved because the outer cylinder does not rotate. The drive and torque sensor are combined to form a single unit with the rotating inner cylinder. 

Prior to the 1990s phenyhnercuric acetate was the primary bactericide and fungicide in latex and waterborne paints. Because of the increasing concerns of mercury toxicity and the potential for high consumer and occupational exposures to mercury when present in paints, the U.S. Environmental Protection Agency (EPA) induced U.S. manufacturers of PMA and other mercury compounds to withdraw their registrations for use of these substances as biocides in paints (see AIercury). Mercury compounds are used only for very limited, specific purposes, such as the use of phenyhnercuric mXx.2LX.e[55-68-5] as a bactericide in cosmetic eye preparations (see Cosmetics). 

Woods, W. B., Prevention of the Microbial Spoilage of Latex Paint, J. Waterborne Coatings, Nov. 1982. 

Latex paints Latex paints today account for more than one-half of the commercial paint sold. They are characterized by quick drying (generally several minutes to several hours), little order, and easy cleanup (with water). Latex paints are polymer latexes to which pigments have been added. The film is formed by coalescence of the polymer particles on evaporation of the water. The polymer itself is not water soluble, though these paints are called waterborne coatings. 

The coatings industry has developed waterborne paints and coatings that greatly reduce VOC emissions. Some applications include automotive coatings, interior latex paints, and polyurethane coatings (Sherman et al., 1998). 

Case studies illustrate that waterborne paints are indeed feasible for many applications ... 

Waterborne paints can reduce the amount of solvent used in vehicle painting from 42.4 to 7.3 kg (Clancy, 1994). 

Novel coating additives are also being studied as a way to ameliorate the disadvantages that have become synonymous with waterborne paints ... 

Possible combinations of red lead with various binder systems are listed in Table 39 [5.114]. Red lead is still used for heavy-duty anticorrosion applications, especially for surfaces bearing residual traces of rust. In waterborne paints, red lead has no advantages over zinc phosphate [5.149]. 

Clausen, P.A. (1993) Emission of volatile and semivolatile organic compounds from waterborne paints-the effed of the film thickness. Indoor Air, 3, 269-75. 

Hansen, M.K., Larsen, M. and Cohr, K.H. (1987) Waterborne paints. A review of their chemistry and toxicology and the results of determinations made during their use. Scandanavian Journal of Work and Environmental Health, 13, 473-85. 

Waterborne paints are usually emulsions of polymer-based binder particles. They are made by making an emulsion of droplets of monomers in water, after which the monomers are polymerized to form solid particles. When applied, the water and possibly other solvents evaporate, and the binder particles fuse to form a solid layer. 

Emulsions are dispersions of one fluid into another. Both oil-in-water and water-in-oil emulsions are encountered. Foams are similar to emulsions, but the dispersed phase is a gas. Emulsions are everywhere some examples of products that are based on emulsions are salad dressings, mayonnaise, egg yolk, milk, margarine, cream, ice cream, waterborne paints and bitumen. Emulsions are generally not stable, so they need to be stabilized against coalescence. One can use surfactants for that, or polymers, such as proteins and polysaccharides, or particles. 

Most household maintenance products contain mixtures of lipophiles and hydrophiles that can produce unanticipated toxic effects. Irritant-induced asthma is an example of such an effect. Solvent-based and waterborne paints contain solvents that are nonsensitizing irritants that are individually not known to induce asthma. Despite this, exposures to both types of paints have been shown to cause the asthma-like condition reactive airways dysfunction syndrome (RADS).I13 14 RADS is discussed in detail in Chapterl8. 

Exposure to waterborne paints is known to induce acute and chronic dermal, respiratory, and CNS effects. 11 All the chemicals listed in Table 12.4 are individually toxic 13 anc[ mixtures of many of these are known to induce unanticipated toxic effects in humans. 14 ... 

Table 12.4 Volatile Components Contained in Waterborne Paints...

Specific teratogens were not identified, but as previously discussed in Sections 12.5 and 13.5, both waterborne paints and oil-based paints contain mixtures of lipophilic and hydrophilic species. Exposures to both types of paints have been associated with low level unexpected effects. Accordingly, the teratogenic results reported in the Dutch study are not surprising. 

Clausen P.A., Wolkoff P. and Nielsen P.A. (1990) Long term emissions of volatile organic compounds from waterborne paints in environmental chambers. Proceedings of Indoor Air 93, Helsinki, Finland, Vol. 3, 557-562. 

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