Polyurethane resins

Abstract

Polyurethane (PU) products are formed by reacting a di- or polyfunctional isocyanate with a polyol in the presence of suitable catalysts and additives. The main occupationally hazard associated with PU chemicals are isocyanates, which have an adverse effect on the respiratory tract including both airway irritation and immunologically mediated outcomes. Exposure to isocyanates and auxiliary chemicals may also result in both allergic and irritant contact dermatitis, as well as contact and generalized urticaria, and the typical localization is hands and face. When patch-testing workers exposed to polyurethane chemicals it is advisable to test with their own work material in addition to the commercially available patch-test preparations of diisocyanates. A second reading on day 7 is advisable since positive reactions may appear late. Positive reactions to methylenedianiline (MDA) (also known as diaminodiphenylmethane) should be taken into account as it may be an important marker for diphenylmethane diisocyanate (MDI) sensitivity.