Phenol-modified cyclo-rubber from synthetic polyisoprene - using reduced amounts of catalysts and giving higher yields with easier processing

摘要

Synthetic polyisoprene is cyclised with phenol in presence of 0.3-5 (0.4-0.8) wt.% Lewis acid and an org. solvent at >150 degrees C and the catalyst separated. The solvent is pref. an aromatic or aliphatic hydrocarbon with b.pt of >=60 degrees C esp. petrol with a wt. ratio of phenol to solvent of 90:10 to 30:70, esp. 70:30 to 40:60. The catalyst is pref. ZnCl2. Use of synthetic polyisoprene in place of natural rubber allows a substantial reducting in catalyst level so that a simpler process, with less washing and effluent water problems, can be used. Yield is increased and the prods have the required properties for paint binders and high value printing inks.