【摘要】 通过分步加入尿素制备废纸纤维板粘合剂,研究了合成工艺对脲醛胶性能的影响。实验得出,采用甲醛与尿素的物质的量比为1.4,尿素分3次投入,在调pH值弱碱性之前加入聚乙烯醇(PVA),合成反应稳定,粘合剂的粘接强度提高,游离甲醛质量分数降低至0.2%以下,贮存期为50d以上。更多还原

【Abstract】 The urea-formaldehyde resin used for waste-paper fiberboard was prepared by stepwise charging of urea.The effect of synthetic process on the properties of resin was studied.The results showed that when the mole ratio of formaldehyde to urea was 1.4,urea was charged by three times and polyvinyl alcohol was charged before the pH value was adjusted,the reaction of the resin was steady,the bonding strength was improved,the free-formaldehyde content in the resin was less than 0.2%,the storage life was over 50d.更多还原