| 摘要 |
A process for producing a polyurethane product comprises steps of (a) supplying at least one polyisocyanate (b) supplying at least one polyol composition comprising at least about 5 weight percent based on total weight of polyols of at least one natural oil based polyol (b1) having a hydroxyl number of at most about 300 and a viscosity below about 10000 mPa·os; and (c) exposing the polyisocyanate and the polyol composition to reaction conditions such that urethane bonds are formed, wherein reaction conditions include the presence of at least one bismuth catalyst. Use of bismuth catalysts is particularly applicable to preparation of open celled, flexible polyurethane foams using polyols made from renewable resources, optionally with other polyols. The invention includes foams made by the process, including viscoelastic foams, preferably having a velvet feel.
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