PROCESS OF NATURAL OR SYNTHETIC POLYISOPRENE CYCLIZATION

摘要

The cyclic polyisoprene is used for the preparation of light-sensitive solutions (SCR) for the photographic process during the production of semiconductor elements and printed circuits. The cyclization of polyisoprene in a solution of hydrocarbons while catalyzed by boron fluoride etherate is terminated after achieving the required level of cyclization by the addition of 1 to 40% by weight of an anion exchanger with tertiary amine groups related to the weight of the polyisoprene, at a temperature of 20 to 140 degrees C, or by the same quantity of a cation exchanger with sulphonic groups. The ion exchangers are removed prior to further processing. The purity of the product can be further improved by washing in a solution of alcohol in water.<IMAGE>