Effect of Adding Conditions of Polyvinyl Alcohol on the Reaction Behavior and Particle Characteristics of Spherical Phenol-formaldehyde Resin Beads

摘要

Phenol-formaldehyde resin (PF) is the oldest synthetic resin. Through the design of synthesis conditions, PF resins with different characteristics can be provided, which are widely used in molding materials, adhesives and impregnation. Spherical PF beads are a hardened resin prepared by a special synthesis method. In this study, a mixture of phenol and formaldehyde was added with triethylamine, polyvinyl alcohol (PVA), and hexamethylenetetramine as a catalyst, granulating agent, and hardening agent, respectively. Spherical PF beads were prepared by a three-stage suspension polymerization in a large-scale water system, and the effects of PVA addition conditions on the reaction behavior and particle characteristics were discussed. The results show that formalin with a concentration of 14 % can be used as a formaldehyde raw material to prepare spherical PF beads by suspension polymerization. The largest spherical PF beads can be obtained with a reactant-liquid ratio of 2/1, a stirring speed of 300 rpm, and an addition amount of BF-04 of 2 %. The particle size of 14-20 mesh accounts for 83.9 % and has the average particle size of 1016 mu m.