Polyurethanes

Polyurethanes (PUR) are the most versatile polymer systems used to formulate elastomeric sealants. Urethane sealants are sold as both one and two-components and generally have good elongation and recovery, excellent abrasion resistance and tear strength. To prevent the oxidative induced degradation of a polyurethane sealant, which results in a loss of physical and mechanical properties, as well as an increase in the discoloration, antioxidants are recommended.

Figure 1 : Gardner Color after Oven Aging at 130°C

Figure 1 illustrates the influence of oxidative degradation on an unstabilized PUR sealant.