水性异氰酸酯交联剂的应用研究

Study on the Application of Aqueous Isocyanate Cross-linking Agent

采用不同链长的聚醚多元醇与多亚甲基多苯基多异氰酸酯(PAPI)反应,制备了两种不同结构的水性异氰酸酯(P-C、P-D),联剂分别加入到氧化玉米淀粉胶黏剂和脲醛树脂胶黏剂中,以改善胶黏剂的胶接性能。通过粘接强度测试研究不同结构、不同用量的水性异氰酸酯对改性胶黏剂的胶接强度和耐水性的影响。实验结果表明:氧化玉米淀粉和脲醛树脂中加入水性异氰酸酯交联剂制备胶合板,胶接强度及耐水性均有显著提高。氧化玉米淀粉胶黏剂中加入10%的水性异氰酸酯P-D后,所制备胶合板的干态剪切强度可达2.64MPa。脲醛树脂胶黏剂中加入7.5%的P-D后,干态、湿态剪切强度分别为1.24MPa和1.23MPa,甲醛释放量为0.31mg/L,达到E0级标准。

Two aqueous isocyanates（P-C、P-D）with different structure were made by the reaction of different chain lengths polyether polyol and polymethylene polyphenyl polyisocynate（PAPI）.In order to improve the adhesive bonding performance,aqueous isocyanate was added to oxidized corn starch adhesive and urea-formaldehyde resin as the cross-linking agent.The effect of different structures and different quantities of aqueous isocyanate on bonging property and water resistance of the two modified adhesives was investigated through adhesive strength testing.Results show that the bonding property and water resistance of plywood made by oxidized corn starch adhesive and urea-formaldehyde resin are obviously improved with aqueous isocyanate as the cross-linking agent.When the proportion of P-D in corn starch adhesive is 10%,the bonding shear strength of dried plywood is 2.64MPa.When the proportion of P-D to total modified urea-formaldehyde resin is 7.5%,the dry bonding shear strength can reach to 1.24MPa and the wet bonding shear strength is 1.23MPa.The formaldehyde emission is 0.31 mg/L,which can achieve the demand of E0 standard.