| 摘要 |
PURPOSE:To improve the surface smoothness, mechanical properties and impact resistance of cured products of the titled composition, by preparing the composition from a terminal ethylenic unsaturation-containing modified urethane oligomer and a free radical-generating catalyst. CONSTITUTION:An organic polyisocyanate is reacted with a polyol having an average equivalent weight of about 75- about 500 and an average functionality >= about 3, in a suitable ratio to form an isocyanato-termiated prepolymer having a free-NCO content of about 0.5-30%. Then, this prepolymer is reacted with an unsaturated monomer selected from the group consisting of an acrylate and acrylamide to form a terminal ethylenic unsaturation-containing modified urethane oligomer having a final free-NCO content of 0- about 20%. Then, the modified urethane liquid polymer is prepared from the above-produced urethane oligomer and a radical-generating catalyst capable of being activated thermally.
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