Epoxy finishes

These intermediates are too small to be used alone, but need to be enlarged and modified to obtain compatibility with other resins. In the case of the phenol formaldehyde resins this is achieved by either using para-substituted phenols where the substituent contains at least four carbon atoms or by reacting the intermediate with the natural resin, rosin, and then esterifying with glycerol or pentaerythritol. These resins have a limited use in stoved epoxy finishes where colour is not an important factor. 

This reaction is an example of a two-pack epoxy finish where the n value of the epoxy resin is 8 to 12. Although giving a high degree of chemical resistance the reaction is sluggish so the common two-pack finishes are usually based on polyamines with epoxy resins having n values of 0 to 2. 

FIGURE 6 A CMU wall treated with block filler and epoxy finish to provide a smooth, cleanable wall surface. (Courtesy of Niagara Walls.)... 

Plastopal . [BA AO] Urea-formaldehyde resins, butanol or methanol ethetified binders for baking finishes, acid-curable coatings, film coatings, ni-trocdlulose finishes, epoxy finishes. 

The solventless epoxy film shows typical epoxy finish properties, but is inevitably less flexible than usual because (a) the films are thicker and (b) the close spacing of the reacting groups leads to a high density of cross-links. The film is, however, very tough and does not shatter easily. 

Unlike epoxy finishes, polyesters undergo appreciable volume shrinkage on hardening. This can cause loss of adhesion, pulling away from edges and other defects. 

System D. Aluminum Epoxy Mastic/Epoxy Finish... 

Can be used on tight rust and marginaiiy prepared surface. The epoxy finish coat is availabie in a variety of colors and has good overall chemical resistance. May be used on carbon steel or concrete. Concrete must be clean, rough, and cured at least 28 days. Hand or power tool cleaning, inciuding water biasting, may be used for surface preparation. 

Since these are two component materials, they must be mixed just prior to application. They require additional equipment and more expertise to apply than a single-packed product. Most epoxy finish coats will chalk, fade, and yellow when exposed to sunlight. 

This, in mould polyester acrylic coating technology, using a proprietary polymer giving fast spray apfdied film cures free of porosity, is designed to provide fast part production. It provides an ideal recoating surface, accepting paints, enamels, lacquers, polyester and epoxy finishes. 

---