Preparation And Application Of Waterborne Polyurethane Adhesive For PVC Artificial Leather

Polyurethane has out-standing performances on elasticity, wear-resisting and pealstrength. Waterborne polyurethane(WPU), on the other side, has more advance for it’slow VOC content, transport safety and environmental friendly. Nowadays, waterbornepolyurethane is replacing solvent-based polyurethane being used as adhesives andcoating agent. In the artificial leather industry, waterborne polyurethane has a widerange of applications on artificial leather fabric, the middle layer, laminating and thesurface finishing agent. In this paper, waterborne polyurethane adhesives wereprepared by using the pre-polymer dispersion method. The factors affecting the pealstrength like the usage of hard segments and soft segments were discussed in thispaper. Eventually, the successfully-made waterborne polyurethane adhesives wereused on polyvinyl chloride artificial production line to test it’s practicability.In this paper, waterborne polyurethane adhesives were prepared with toluenediisocyanate(TDI) and1,6-diisocyanatohexane(HDI) as hard segments, polyesterpolyol(N-56) and polypropylene oxide glycol(PPG) as soft segments. Series of testsincluding FTIR, TG and peel strength were used to investigate the characteristic andproperty of WPU. The results indicate that the Pre-polymer could be well preparedwhen the heat preservation temperature is70-80℃and the holding time is2hours.The peal strength can reach28N·25mm-1and with good water-prove ability by using40%HDI in hard segments and using70%N-56in soft segments. Whenn(-NCO)/n(-OH)=1.7and using isophorondiamine as post chain extender, the peelstrength can reach38N·25mm-1.On PVC artificial leather production line, the formulating researches indicate thatthe usage of thickener, antifoaming agent and flatting agent should be0.7%,0.4%and0.6%, respectively. Using4%of gaseous silica as filler can increase the bondingeffect, and the peal strength can rise from25N·25mm-1to28N·25mm-1. Theapplication test on production line indicates that the peel strength is above30N·25mm-1to different base textiles. The conclusion is that the WPU adhesives fromthis paper are capable of replacing solvent-based polyurethane being used asadhesives on PVC artificial leather production line.