Water-thinned epoxy coating

One can rationalize a need for small rubber inclusions in some of the newer approaches to waterborne and high solids epoxy coating systems. Water-thinned epoxy coating compositions are described (48) where the two-component system consists of a nitrile rubber modified epoxy resin in the epoxide component and a styrene/ butadiene/methylmethacrylate latex modifier for an emulsion-based polyamide hardener component. Showing improved adhesion, impact and water resistance, the paint has good wetting characteristics and can be formulated to a high solids content at low viscosity. 

Initially, with the grey paint, it was thought that the thinness of the coating combined with its plasticity was causing the paint to peel from the surface in a ductile manner, it being further plasticised by the uptake of water. These observations were not true for the epoxy coated panels as the film thickness... 

The best measure to prevent corrosion of an oil tank bottom is to apply a thin film of epoxy copolymer and coal tar epoxy coating. A drainage facility may be incorporated for minimizing the buildup of water at the tank bottom. At the exterior of the tank bottom, corrosion penetrating... 

Procedure. Core floods were carried out in horizontally mounted Berea sandstone cores of length 61 cm and diameter 5 cm. Porosity varied from 18 to 25% and brine permeability from 100 to 800 Jim2. The cores were coated with a thin layer of epoxy and cast in stainless steel core holders using molten Cerrobend alloy (melting point 70°C). The ends of the cores were machined flush with the core holder and flanges were bolted on. Pore volume was determined by vacuum followed by imbibition of brine. Absolute permeability and porosity were determined. The cores were initially saturated with brine (2% NaCl). An oil flood was then started at a rate of lOm/day until an irreducible water saturation (26-38%) was established. 

Decreasing the water absorption mechanically , i.e. by coating the external surface of an article, produces good results. It was shown that coating of epoxy syntactic foams with a thin layer of epoxy resin reduces the water absorption more than tenfold, even under high hydrostatic pressure 140). 

If colour is very strong, litho in thin layers is not so rub-resistant as letterpress because of low varnish level. Note that rub resistance and brightness can usually be improved by the addition of over-lacquers or varnishes (based on shellac (spirit), nitrocellulose, Saran, vinyl, epoxy, water varnishes, etc.) or lamination (cellulose acetate, polypropylene, PVC, etc.). Coatings or laminations may also provide heat sealability. 

Paints, in general, are not useful for protecting buried structures, one reason being that mechanical damage to thin coatings by contact with the soil is difficult to avoid. Tests have shown that, for this purpose, their fife is relatively short. Coatings based on coal tar or on fusion-bonded epoxy have been found to be far more practical. Similarly, the usual linseed-tung oil paints are not durable for metal structures totally immersed in water, except possibly for short periods of time on the order of one year or less. In hot water, life is stiU shorter. More ade-... 

Description The only water-based urethane epoxy encapsulant. Mixed by customer. Very thin coating. Separate primer and encapsulant for outside surfaces. Training is required by manufacturer before use, both to ensure safety and to validate the 20-year guarantee. Safety/precautions No volatile chemicals, nontoxic, noncaustic, nonacidic, nonflammable. Environmentally and worker safe. 

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