| 摘要 |
Improved rigid urethane and isocyanurate foam compositions having improved fire resistance are described. The urethane foams are based on furan compositions having the formula: <IMAGE> +TR <IMAGE> <IMAGE> <IMAGE> where L is lower alkyl or M, and M is <IMAGE> <IMAGE> +TR <IMAGE> and from about 100% to about 500% of a stoichiometric amount of a reactive polyisocyanate to produce a foamable composition, and sufficient blowing agent to create a foam having a density from about 1.5 to about 5 pounds per cubic foot. The product has improved fire resistence. The disclosure also described the method of decreasing the flame hazard potential of a rigid foam by adding two urethane or isocyanurate foaming ingredients the appropriate amount of one or more of the compositions listed above. The polymers described are chiefly made from adding propelyne oxide to bis (hydroxymethyl) furan.
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