胶合板用改性脲醛树脂预压强度的研究

Study on Prepressing Intension of Modified UF Resin for Plywood

本研究采用三聚氰胺及 PVA对脲醛树脂进行改性 ,探讨改性脲醛树脂的合成工艺和性能与预压强度的关系。结果表明 ,较大三聚氰胺加量不利于板坯预压强度的提高 ;PVA能明显改善树脂的初粘性 ,但初粘性不决定预压强度 ;反应终点温度对预压强度影响较大 ,粘度对预压强度的影响并不显著 ;高固体含量树脂的预压强度低 ;较快固化的树脂预压强度较好 ;

The urea formaldehyde (UF) resin for plywood was modified with melamine and polyvinyl alcohol (PVA). The effects of modified UF resin makings including final molar ratio, quantity of melamine, PVA and final temperature, and property indexes including viscosity, solid content and free formaldehyde content on prepressing intension of assembled mat were studied. Results showed that larger quantity melamine had no advantage of improving the prepressing intension, and PVA could help to increase original viscosity obviously, but the original viscosity could not determine the prepressing intension. The high temperatures of final reaction and short curing time were good for the prepressing intension, but prepressing intension decreased with solid content of resin increased. The low free formaldehyde content had little effect on prepressing intension.