木薯淀粉基环保型木材胶粘剂的合成研究（Ⅱ）--基于淀粉水解液改性脲醛树脂的配方优化

摘要

以木薯淀粉水解液及少量三聚氰胺对脲醛树脂进行改性，制得性价比良好的环保型木材胶粘剂。研究水解液的水解程度及添加量、甲醛/尿素（F/U）摩尔比等因素对胶合强度的影响，并采用正交设计法优化试验配方。结果表明：（1）水解液粘度为40.0～45.0 s （涂-4杯，30℃）时改性效果较好；（2）优化后配方是甲醛与尿素的摩尔比为1.3，水解液和三聚氰胺分别占胶粘剂总量的25.5％、3.6％；（3）所压制桉树三层胶合板胶合强度达到国家II类板要求，游离甲醛释放量达到E2-E1级。%Cassava starch hydrolysate and a small amount of melamine were used to modify the urea-formalde-hyde resin adhesive to produce a modified resin adhesive which possesses a high performance price ratio and en-vironmental friendly quality.Effects of the hydrolysis degree,the addition of hydrolysate,the molar ratio of formaldehyde to urea (F/U )on bonding strength of the modified urea-formaldehyde resin were investigated. Their formulations were further optimized in orthogonal design.It is shown that cassava starch hydrolysate is op-timal when viscosity falls between 40.0 s and 45.0 s (Tu-4 cup,30 ℃) for UF adhesive modification.The optimal formulation is F/U=1.3 when melamine is 3.6%of the UF glue in proportion and starch hydrolysate is 25.5%.The bonding strength of repression eucalyptus plywood is up to the requirement of Plywood Ⅱ in Na-tional Standard,while the emission of free formaldehyde of the plywood satisfies E2 -E1 .