Waterborne coating

Most of the important types of modem solvent-borne coatings — epoxies, alkyds, acrylics — are also available in waterborne formulations. In recent years, even urethane polymer technology has been adapted for use in waterborne coatings [1]. However, waterborne paints are not simply solvent-borne paints in which the organic solvent has been replaced with water the paint chemist must design an entirely new system from the ground up. In this chapter, we discuss how waterborne paints differ from their solvent-bome counterparts. 

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This is a particularly troublesome competing reaction when the olefin oxide, eg, ethylene oxide, produces the more reactive terminal primary hydroxy group. Glycol ethers are used as solvents ia lacquers, enamels, and waterborne coatings to improve gloss and flow. 

Cellulose esters of aromatic acids, aUphatic acids containing more than four carbon atoms and aUphatic diacids are difficult and expensive to prepare because of the poor reactivity of the corresponding anhydrides with cellulose Httle commercial interest has been shown in these esters. Of notable exception, however, is the recent interest in the mixed esters of cellulose succinates, prepared by the sodium acetate catalyzed reaction of cellulose with succinic anhydride. The additional expense incurred in manufacturing succinate esters is compensated by the improved film properties observed in waterborne coatings (5). 

Significant advances in waterborne coatings have been made by PPG Industries utilizing epoxies as co-resins. These coatings are used in cathodic electrodeposited systems, widely accepted for automobile primers. Many patents have been issued for this important technology (50,51). 

Example 9. Two-Component Waterborne Polyurethane Coating. This example utilizes the PUD from Example 8 in a two-component, waterborne coating formulation. An HDI-based, water-dispersible isocyanate is also prepared. 

Nicholson, J. W. (1985). Waterborne Coatings. OCCA Monograph No. 3. London Oil and Colour Chemists Association. 

Detailed quantitative analyses of the data allowed the production of a mathematical model, which was able to reproduce all of the characteristics seen in the experiments carried out. Comparing model profiles with the data enabled the diffusion coefficients of the various components and reaction rates to be estimated. It was concluded that oxygen inhibition and latex turbidity present real obstacles to the formation of uniformly cross-linked waterborne coatings in this type of system. This study showed that GARField profiles are sufficiently quantitative to allow comparison with simple models of physical processes. This type of comparison between model and experiment occurs frequently in the analysis of GARField data. 

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

Waterborne coatings, 7 127-128, 10 443 Waterborne coating technologies, 10 349 Waterborne contact adhesives, phenolic resins in, 18 784 Waterborne polyamides, 10 400 Water-borne polyurethane coatings,... 

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. 

Why have latex waterborne coatings been popular with the general public ... 

Superheated and supercritical water are used in several applications. Supercritical water is most often used in the destruction of organic wastes, including some chemical warfare agents, as an alternative to incineration (Katritzky et al., 1996 Sherman et al., 1998). Recent reports describe the use of both forms as a solvent and as a reactant in synthetic chemistry (Katritzky et al., 1996 An et al., 1997). Some of the reactions investigated include metal-mediated alkyne cyclizations, Pd-catalyzed al-kene arylations, aldol reactions, the Fischer indole synthesis, and hydrolysis reactions. Waterborne coatings and the destruction of wastes in supercritical water are fully... 

Finally, some waterborne coatings incorporated reactive diluents, as in high solids coatings. For example. Blank (1992) describes using a urethane diol as a reactive diluent to replace glycol ether cosolvents in emulsion coatings. 

Provdder, T., Winnik, M. A. and Urban, M. W., Eds. (1996) Film Formation in Waterborne Coatings, American Chemical Society, Washington, DC. 

Applications used in waterborne coatings and adhesives, film modifications, high-performance coatings, and inkjet technology... 

Waterborne Coatings, These coatings utilize either liquid or solid epoxy resins that have been modified to allow their use with water. They are usually in the form of emulsions, suspensions, dispersions, or water-dilutable resins that can be heat- or RT-cured. They are applied by convenient methods such as roller-coating, dipping, spray, or electro deposition. 

UV curable waterborne coatings made of PU-acrylate ionomers have been synthesised and characterised by IR spectroscopy [93]. Similarly a series of novel PU ionomers with polydioxolane (PDXL) as soft segment is prepared and identified by FT-IR spectroscopy [94]. 

Uniqema Synperonic Surfactants, Resin Emulsification for Waterborne Coating and Adhesives, Uniqema, Wilmington, DE, 1999. 

Surface treatments are often necessary for aesthetic and performance reasons. This can involve printing or lacquering, using both solvent and non-solvent based inks, which are applied to the surface using rollers, pads, silk screen, inkjet or lasers. Waterborne coatings are environmentally more desirable and silicone surfactants are claimed to give the best performance to improve substrate wetting (456). 

In applications, where aluminum powder is requested (e.g. in powder coatings) or where the rest of the remaining mineral spirit would not be compatible with the application medium (e.g. in printing inks, waterborne coatings and inks, master-batches etc.), the mineral spirit of the press cake is removed in vacuum driers and substituted by any kind of solvent, water, plasticizer, mineral oil or other liquids. 

Other metallic pigments are coated with inorganic (mostly siUca) or organic (polymer) materials to improve their chemical and thermal stabiUty in waterborne coatings, powder coatings, masterbatches, non-conductive coatings etc. 

Due to its chemical properties, aluminum reacts in aqueous systems, especially in alkaline or acidic media, to yield hydrogen gas. In the case of aluminum pigmented waterborne coatings, this would not only be a safety risk, but would also destroy the metallic effect [5.182]. 

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