Industrial applications of Maya-type pigments
Palygorskite clay and Indigo was used to make synthetic Maya Blue. Indigo derivatives were used to synthesize colors of purple, pink and brown. Several tests were performed to analyze the potential use of the Maya type pigments in coatings applications compared to those pigments that are already commercially available. Oil Absorption values for Maya type pigments were in the range of 62–68g/100g, while that for Copper Phthalocyanine blue was 61.13g/100g and Ultramarine Blue was 42.74g/100g. Specific gravity was 2.29 and the critical pigment volume concentration was in the range of 37.23–39.42. K/S ratio for these pigments ranges from 0.34–1.08. The resistance of the Maya type pigments to acid rain was tested using simulated lab test called Kesternich test. Results show that the presence of calcium carbonate impurities affects the stability of Maya pigments to acid rain resulting in the formation of calcium sulfate. Resistance to ultraviolet light and moisture condensation were determined using a UV weathering chamber that simulates real weather conditions. Color difference values were recorded before and after exposure to the simulated weathering. Results of the exposure test on acrylic solvent based paints after 500 hours shows Maya type pigments have superior performance as compared to Ultramarine blue and slightly inferior performance as compared against Copper Phthalocyanine Blue. Water based Maya type paints show superior performance as compared to Ultramarine Blue and superior or comparable performance as compared to Copper Phthalocyanine. Results of Maya type pigments in injection molded plastics shows superior or comparable performance as compared against commercially available pigments. ^
Saliya, Rajesh Gopalan, "Industrial applications of Maya-type pigments" (2004). ETD Collection for University of Texas, El Paso. AAIEP10792.