Preparation method of high-purity cyanate ester

The invention provides a method for producing high-purity cyanate ester resin. The method comprises the following steps: mixing cyanogen halide, a bisphenol compound, a tertiary amine compound and a catalyst according to a molar ratio of (1-1.1): 1: (1-1.3): (0-0.02); and controlling the mixture to react at the ambient temperature of below 20 DEG C, and separating and purifying to obtain the high-purity cyanate ester. The proportions of the cyanogen halide, the bisphenol compound and the tertiary amine compound are controlled to be similar, and meanwhile, reaction conditions are combined, so that the side reaction yield is effectively reduced, and the yield and the purity are improved. 本发明提供一种生产高纯氰酸酯树脂的方法，包括：取卤化氰、双酚类化合物、叔胺化合物、催化剂按照摩尔比（1-1.1）：1：（1-1.3）：（0-0.02）的比例混合；控制混合物在20℃以下的环境温度下反应，经分离纯化，获得高纯氰酸酯。本发明控制卤化氰、双酚类化合物、叔胺化合物的比例相近，同时结合反应条件，有效减少副反应产生量，提高收率及纯度。