PREPARATION AND CHARACTERIZATION OF WATERBORNE POLYURETHANE AS SHOE ADHESIVES

Abstract

A series of waterborne polyurethane(WBPU) adhesives for shoes were synthesized by a prepolymer process using dimethylol propionic acid(DMPA) and sucrose as a hydrophilic agent and a cross-linking agent,respectively.Their structures and thermal behaviors were studied by means of FTIR and DSC.Their water swelling,curing time,mechanical properties,e.g.tensile strength,elongation at break and T-peel strength were measured for all samples with different sucrose contents(0～6.82 wt%).The results showed that the sucrose dispersed well as an incorporated state in the polyurethane phase.The curing time of WBPU samples were decreased with increasing sucrose content at the same treating temperature.The water swelling decreased with increasing sucrose content having an optimum sucrose content at 4.13 wt%,and then it increased slightly with further increase of sucrose content.The tensile strength increased from 8.1 MPa to 22.8 MPa,while the elongation at break decreased from 933.5% to 618.7%.The initial peel strength and final peel strength were significantly increased up to an optimum content of sucrose and then decreased slightly with excess sucrose.In addition,it is noted that polyurethane prepolymers more easily remained at an aggregated state during the process of synthesis,and the adhesive strength of the result products decreased when the sucrose content was more than 5.52 wt%.