Polyurethanes black pigments

Arylamines act as primary antioxidants by donating hydrogen. They are highly effective because they act both as chain terminators and peroxide decomposers. Negative properties include their tendency to discolour and stain and their toxicity, which precludes their application in non-pigmented plastics and those intended for food use. Arylamines are included in black wire and cable insulation and polyurethanes. 

The urethane linkage is resistant to alkalis and thus urethane oils and alkyds have better alkali resistance than ordinary alkyds. This is usually accompanied by better water resistance. Urethane oils and alkyds possess a property common to all polyurethane finishes good abrasion resistance. It is claimed that they are superior to oils and alkyds for the dispersion of difficult organic pigments and carbon black, but in pigmented form they are prone to chalk and lose gloss earlier than normal alkyds and oleoresinous finishes. 

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