Preparation method of isocyanate-based polyimide foam

Abstract

The invention provides a preparation method of isocyanate-based polyimide foam. The preparation method comprises that 1, polybasic aromatic anhydride is heated and dissolved in a polar solvent and undergoes a reaction with fatty alcohol to produce a polybasic aromatic anhydride derivative solution, 2, the polybasic aromatic anhydride derivative solution and a foam stabilizer are blended to form a white material, 3, polybasic aromatic anhydride and isocyanate undergo a reaction to produce a black material, 4, the foaming white material is immediately poured into the foaming black material at a room temperature under normal pressure, and the mixture is uniformly stirred, then is fast poured into a mold and is subjected to free foaming molding to form a foam intermediate and 5, the foam intermediate is heated and cured to form the isocyanate-based polyimide foam. The preparation method inhibits production of an amino group and an isocyanate group in foam material preparation, reduces a polyurea generation amount and improves isocyanate-based polyimide foam heat resistance, heat stability and flame resistance. The preparation method has the advantages of simple processes, excellent product comprehensive properties, and industrial production and wide application feasibility.

Description

technical field [0001] The invention relates to a method for preparing polymer foam material, in particular to a method for preparing isocyanate-based polyimide foam. Background technique [0002] Isocyanate-based polyimide foam belongs to a class of polyimide foams. Due to the free foaming molding process at room temperature and relatively low requirements for the purity of raw materials, it is different from the polyimide foam prepared by the powder method. Compared with the obvious industrial production advantages and market price advantages, it has stronger market competitiveness. [0003] According to patent documents such as US3300420, US4026833, US7541388, CN101812232A, CN102127225A and related paper reports of people such as Zhan Maosheng and Wang Liancai, the preparation method of isocyanate-based polyimide foam mainly contains two kinds of modes at present: 1. at first with polybasic aromatic anhydride and Excessive isocyanate reacts to form a black material, and ...

AI Technical Summary

Problems solved by technology

However, in the first way, due to the excessive amount of isocyanate, the amino group and residual isocyanate generated in the free foaming molding process will not continue to generate polyimide precursors but will form polyimide with poor thermal stability and flame retardancy. Urea, ultimately leading to a certain gap in the overall heat resistance and flame retardancy of the foam compared with pure polyimide foam, and the density of the foam obtained in this way is relatively high; in the second way Since the isocyanate is not pre-polymerized with the polybasic aromatic anhydride, the reaction between the isocyanate and water will be more violent in the foam molding process in this way compared to the first way, and the amount of amino groups and gas generated will be more, although The generated amino group will react with polybasic aromatic anhydride derivatives to form a polyimide precursor, but at the same time, the amino group will also react with a large number of unreacted isocyanate groups to form a large amount of polyurea, which will also greatly reduce the overall polyimide foam. Excellent heat resistance, thermal stability and flame retardancy, but the density of isocyanate-based polyimide foam produced in this way is relatively low