| abstract |
An asphaltic polyurethane or isocyanurate foam (12) useful in roofing applications. The foam is made from asphalt having a penetration range of between approximately 5-25, a softening point of between approximately 120 °F and 200 °F, and an asphaltene content of no more than about 30 %. This asphalt is liquified and mixed with a mixture of polyols such as Voranol 270, Multranol 9138, and castor oil. Other chemicals, such as a surfactant, a viscosity reducer, and a flame retardant can also be included in this mixture. The mixture is then brought to a temperature of between approximately 140 °F and 220 °F, mixed with water and a polyisocyanate in a molar ratio of polyisocyanate:polyol of between about 0.95:1 and about 1.3:1, and reacted to form an asphaltic polyurethane foam. Alternatively, a molar ratio of polyisocyanate:polyol of between about 2.0:1 and about 2.7:1 can be used. In this case, an asphaltic isocyanurate foam is produced. |