| 摘要 |
Disclosed is a method for improving the flexibility of a phenol or mercapto resin wherein an aliphatic hydroxyl-functional polyol or polyepoxide component is partially capped with a phenol or mercapto capping agent followed by chain extension with a polyisocyanate under reaction conditions wherein said polyisocyanate substantially selectively reacts with aliphatic hydroxyl groups or epoxy groups residual from the prior step of the process. The ratio of components is such that a resin predominating in one or more of the following general structures is produced: <IMAGE> (I) <IMAGE> (II) <IMAGE> (V) <IMAGE> (VI) where, R and R' each is a phenol functional group or a mercapto functional group, A and B each is an organic chain residue of said component containing functionality epoxy, Poly and Poly' each is an organic chain residue of said component containing aliphatic hydroxy functionality, X is an aliphatic hydroxyl group, the wavy line represents an organic chain residue of said polyisocyanate, n is 1-4, m and p each is 0-2, and q and s each is 1-15.
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