复合改性淀粉基木材胶粘剂的制备

Preparation of composite modified starch-wood adhesive

首先糠醛和聚乙烯醇(PVA)在酸性条件下合成聚乙烯醇缩糠醛树脂;然后将该树脂和环氧氯丙烷对氧化淀粉进行2步改性,并加入适量的亲水改性多异氰酸酯,制得多层人造板用淀粉基木材胶粘剂。研究结果表明:当pH为10、w(聚乙烯醇缩糠醛树脂)=20%和w(环氧氯丙烷)=1.0%(均相对于氧化淀粉胶粘剂质量而言)时,该胶粘剂的湿态剪切强度升至0.68 MPa;施胶前加入3.0%亲水改性多异氰酸酯(相对于氧化淀粉胶粘剂质量而言),则该胶粘剂的胶接强度(为0.72 MPa)满足GB/T 9846—2004标准中Ⅱ类胶合板的指标要求。

First, the poly （vinylalcohol furfural） resin was synthesized by reaction between furfural and polyvinyl alcohol （PVA） under acidic condition. Then, the oxidized starch was modified by the above resin and epichlorohydrin through two-step method, and the hydrophilic modified polyisocyanate was appropriately introduced into system, so the starch-wood adhesive for multilayer artificial board was prepared. The research results showed that the wet-shear strength of the adhesive was increased to 0.68 MPa when pH was 10, and mass fractions of poly （vinylalcohol furfural） resin and epichlorohydrin were 20% and 1.0% respectively in oxidized starch adhesive. The bonding strength （0.72 MPa） of adhesive could meet the index requirements of II-plywood in GB/T 9846--2004 standard when the hydrophilic modified polyisocyanate, which mass fraction was 3.0% in oxidized starch adhesive,was introduced into system before using adhesive.