| 摘要 |
The present invention relates to a liquid, storage-stable isocyanate having a viscosity of less than 100,000 mPa.s at 23 DEG C. and an isocyanate content of from about 9 to 20% by weight, and is prepared by reacting a solid 4,4'-methylene bis(cyclohexyl isocyanate) with a blocking agent. The 4,4'-methylene bis(cyclohexyl isocyanate) must contain at least 35 to 100% by weight of the trans,trans isomer. More generally, this liquid isocyanate is prepared by reacting the solid or semi-solid 4,4'-methylene bis (cyclohexyl isocyanate) with the blocking agent in quantities such that at least 22% but less than 60% of the isocyanate groups are blocked. Preferred blocking agents are the ketoximes, and mixtures thereof. |
