| 摘要 |
Polyurethane/polyisocyanurate foams having a NFPA 101 Class A rating (ASTM E-84) are produced from a foam-forming reaction mixture that includes: an organic polyisocyanate, an isocyanate-reactive composition that includes at least one polyether polyol or polyester polyol with a nominal hydroxyl functionality of at least 2.0, a blowing agent composition and at least one halogen-free flame retardant. The blowing agent composition includes: (1) up to 5% by weight, based on total weight of the foam-forming composition, of one or more hydrocarbons having an LEL less than 2% by volume in air; and/or (2) a hydrocarbon having an LEL greater than 2% by volume in air; and (3) up to 1% by weight, based on total weight of foam-forming composition, of water. |
