Coating solvent-free liquid epoxy

Thermosetting epoxy and polyurethane chemically-cured liquid resins can provide, among other characteristics, superior abrasion resistance coatings. Solvent-free formulation applied by hot spray techniques can achieve film thicknesses of up to 5 mm. 

Comparisons of the properties of solvent-free liquid coatings based on unmodified bisphenol A epoxies cured with varying amine hardeners are shown in Table 6. Examples include diethylenetriamine [111 -40-0] y H2NC2H4NHC2H4NH2 (7), triethylenetetramine [112-24-3]>... 

A plastisol may be regarded as an organosol in which the continuous phase is almost entirely liquid plasticizer (small amounts of solvent are used for viscosity adjustment). PVC plastisols are made from PVC powder, adipate and phthalate ester plasticizers and minor amounts of epoxy-type resin in solution to aid pigment dispersion and to help (with other additives) to keep the polymer stable to heat and oxidation. The resultant coating is nearly solvent-free and so can be applied in thick films (100-250 m) and stoved without disruption by escaping solvent. The plasticizer penetrates the particles, aiding sintering as the metal substrate reaches c. 200°C in 30-60 s. 

In the development of maintenance and marine coatings, the emphasis has been on the development of low-solvent, or solvent-free, coatings to satisfy EPA volatile organic content standards. Thus liquid epoxy systems based on polyamidamines have been developed. Epoxies have also been formulated as powdered coatings, thus completely eliminating solvents. 

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