| abstract |
Embodiments of the invention provide for polyurethane or polyisocyanurate foam formulations. The formulations include a formulated polyol, a polyisocyanate, and a blowing agent such that the stoichiometric index of the polyisocyanate to the formulated polyol is above 250. The formulated polyol includes (i) from about 20 to about 60 percent by weight of an aromatic polyester polyol, (ii) from about 10 to about 30 percent by weight of a Novolac-type polyether polyol, and (iii) from about 5 to about 40 percent by weight of a polyether polyol including a sucrose- or sorbitol-initiated polyol. Components (i), (ii), and (iii) are selected so that the formulated polyol as a whole has an average functionality of at least about 2.4. |