Gelation and fusion of vinyl plastisols



The gelation of vinyl plastisols at constant temperature has been found to follow the equation ln [(CCe)/(UCe)] = (− π2/a2)Dτ + ln (8/π2), where C is the resin phase concentration, Ce the equilibrium resin phase concentration, U the critical resin phase concentration, a the average particle size, D the diffusion constant, and τ the time required for the onsent of gelation. A light reflectance apparatus capable of measuring the gelation process is described. The effect that various resin–plasticizer parameters have on the gelation and fusion process is discussed. The light-reflectance apparatus is also useful for estimating various resin and formulating parameters.