Document 46rDMzDRQnw6J2rVjwxE3KwN

Of the many types and grades of color pigments, a few of the more important are briefly mentioned. White Pigments Cadmium pigments are better than iron pigments in overall performance but they have poorer lightfastness and are more expensive. Titanium dioxide is the most important white pigment. Its hiding power is ex cellent and it is highly compatible with most vehicles. Zinc oxide is also a fine white pigment but lacks the hiding power and the overall compatibility of titanium dioxide. Antimony oxide is used mostly as an additive for imparting fire retardance and UV light resistance. Black Pigments Carbon blacks are small in particle size and provide a fine hiding quality. However, they are poor for tinting purposes. Lampblacks are better than carbon black for tinting but are inferior in other properties. Other Pigments Blue Pigments Extender pigments such as calcium sulfate are relatively inexpensive but they impart Phthalocyanine blue pigments have the only low opacity. One of their main uses excellent qualities of high tinting strength, is for the creation or control of gloss. lightfastness, heat stability, chemical resis Metallic pigments and zinc and strontium tance, and exterior durability. chromates are classified as reinforcing pigments since they impart additional Green Pigments desirable physical properties to the coating. Phthalocyanine green pigments have the same excellent qualities as listed for the phthalocyanine blue pigments. However, interior designers are now specifying metallic pigments to create the new "metallic look" strictly for decor. Chrome oxide is good on exterior ex posure, heat stability, and 1R reflectance. I SAFETY REGULATIONS Yellow Pigments Chrome yellows (lead chromates) are available in many shades. They provide good tinting strength and hiding power but they are toxic, have poor exterior color retention (darken), and exhibit little resistance to an alkaline environment. Orange Pigments Molybdate oranges provide good tinting and hiding properties but they darken on exterior exposure. Red Pigments Ferric oxides are very good except for poor exterior gloss retention and poor tint quality. A proposed Federal Standard effective December 31, 1973 restricts the lead con tent of coatings to 0.06% of the total weight of the contained solids or dried film when i such coatings are intended or packed in a form suitable for use in or around the house hold and on articles for use by children. A few states have already put this standard into effect. This regulation imposes severe limita tions on the choice of many of the con ventional pigments as discussed above, especially in the red, orange, yellow, and green colorant classes. Transition to es sentially lead-free coatings involves an arduous and costly process but presumably the change will provide safer although more expensive coating systems. ; | [ '{ Pign MA] ROB Tech HER Grou Mail Mob, Edisi A marine coating ing used on marin environment there of coatings for v to the harshness greatest demand coatings. Thereto] are designed ess< prevention of corn This chapter d< pigments play in tions. In additio systems are pres nomic benefits. Coating system tures can be con another. For e; paint applied to shipbottoms to Similarly, anticori offshore towers equally well on ve conditions. GLD33803