LACTONE POLYMER HAVING NARROW MOLECULAR WEIGHT DISTRIBUTION AND ITS PREPARATION

摘要

PURPOSE:To prepare a lactone polymer having narrow molecular weight distribution and useful as a raw material of polyurethane such as urethane elastomer, by the ring opening polymerization of lactone using a specific amount of stannous chloride as a catalyst. CONSTITUTION:The objective polymer having a molecular weight of 500-5,000 and (weight-average molecular weight)/(number-average molecular weight) of 1.1-2.0 is prepared by the ring opening polymerization of epsilon-caprolactone using a polymerization initiator such as a diol (e.g. ethylene glycol) in the presence of 0.1-50ppm of a stannous halide (e.g. chloride, bromide, iodide, etc.) based on the amount of the epsilon-caprolactone. The reaction is carried out generally at 100- 250 deg.C, preferably at 120-190 deg.C. EFFECT:The resultant polymer has low viscosity and a somewhat low melting point.