| 摘要 |
PURPOSE:To improve elasticity characteristics as the joint filler for buildings, by using as the principal ingredient of a sealant an isocyanate group-contg. prepolymer obtd. by mixing a low-molecular acrylic copolymer with a poly oxyalkylene polyol in a specified ratio and reacting the mixture with an org. diisocyanate compd. CONSTITUTION:0.001-10pts.wt. reaction accelerating catalyst and 30-250pts.wt. filler are blended with 100pts.wt. isocyanate grou-contg. prepolymer obtd. by reacting an org. diisocyanate with a mixture of the following components A and B, and the blend is dehydrated to obtain a sealant. Component A is a low-molecular acrylic copolymer contg. a functional group reactive with the isocyanate group, obtd. by copylymerizing an unsaturated monomer contg. a functional group reactive with the isocyanate and an unsaturated monomer of the formula in the presence of a chain transfer agent and/or a polymn. initiator contg. a functional group reactive with the isocyanate. Component B is a polyoxyalkylen polyol having a number-average MW of 6,000 or below and contg. hydroxyl groups as a functional group reactive with the isocyanate. The mixing ratio of A to B is 0.8-1.25 (molar ratio).
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