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为了获得稳定性较好的水性聚氨酯(WPU)胶粘剂,以丙酮为溶剂、聚醚(N210)为软段、二苯基甲烷-4,4′-二异氰酸酯(MDI)为硬段、二羟甲基丙酸(DMPA)为亲水性扩链剂、三乙胺(TEA)为成盐剂和聚乙烯醇(PVA)为增稠剂等,制备了环保型木材粘接用WPU胶粘剂。研究了MDI、N210、DMPA、TEA和PVA用量等对乳液稳定性、胶粘剂剪切强度及黏度的影响。结果表明:当n(MDI)∶n(N210)∶n(DMPA)∶n(TEA)=2.4∶1∶0.8∶0.64、w(PVA)=2.0%～3.0%时,可制得常温(20～30℃)存放90 d以上、剪切强度超过4.2 MPa的稳定WPU胶粘剂。
In order to obtain a better stability of water-based polyurethane (WPU) adhesive, acetone as solvent, polyether (N210) as soft segment, diphenylmethane-4,4’- diisocyanate (MDI) as hard segments, (DMPA) as hydrophilic chain extender, triethylamine (TEA) as salt-forming agent and polyvinyl alcohol (PVA) as thickener, etc. to prepare environmentally-friendly WPU adhesive for wood bonding. The effects of MDI, N210, DMPA, TEA and PVA on the stability of emulsion, shear strength and viscosity of adhesive were studied. The results showed that when the mass ratio of n (MDI): n (N210): n (DMPA): n (TEA) = 2.4:1:0.8:0.64 and w (PVA) = 2.0% ~ 3.0% ~ 30 ℃) Stored more than 90 d, the shear strength of more than 4.2 MPa stable WPU adhesive.