Based on the study on preparation of sulfonate WPU emulsion adhesive of solid content at about 50% by the acetone method carboxylate-modified composite WPU emulsion adhesives was prepared. The impact of the modification on the properties of sulfonate WPU adhesive were also investigated. The results showed that when DMPA content was 1.6% (mass)

A95 content was 1.8% (mass)

n(PBA2000)/n(PBA3000) was 4/6 and n(HDI)/n(IPDI) was 4/6

the emulsion obtained a excellent mechanical and adhesive performance. Infrared spectroscopy showed that the composite WPU was prepared successfully. DSC analysis indicated that the melting temperature of composite WPU was about 48.03℃

while that of the sulfonate WPU was about 44.52℃. The composite WPU peak area were higher with better crystalline performance. TEM analysis revealed that both WPU emulsion particles were spherical and uniformly dispersed. Particle size distribution analysis showed that the particle size distribution of composite WPU emulsion was wider than that of the sulfonate WPU emulsion. GPC analysis displayed that the molecular weight of two types of WPU were similar

and thus the influence of modification on the molecular weight was small. TGA analysis found that the thermal decomposition reached the end at 550℃ with slight better heat resistance of sulfonate WPU. The integrated performance analysis showed that the two adhesives had better heat resistance

mechanical properties and adhesion performance

indicating that the performance of composite WPU emulsion adhesive was improved obviously

while its performance was also improved greatly as compared to the carboxylic/sulfonate WPU synthesised by the traditional method.