Use of Solubility Parameters in Solvent Based Adhesives

Manufacturer: We are manufacturing water based adhesives based on PVac and natural rubber latex. Recently we have decided into venture into solvent based adhesives due to the response to market requirement of our customers. We were advised to look into "solubility parameters" of both polymers we used and the available solvents to determine what solvents are best for what polymers.

What is "solubility parameters" anyway?

John Woon (Senior Latex Consultant): To cut the long story short, solubility parameter is a numerical estimate of the degree of interaction between materials (e.g. solvent with solvent or solvent with polymers), which indicates how good is the miscibility or solubility of the different materials when mixed together. Materials with similar values of "solubility parameter" are likely to be miscible e.g. a polymer with similar solubility parameter of its solvent would be easily dissolved in that solvent.This makes your life so much simpler when you want to choose a suitable solvent for your polymer such as polychloroprene and natural rubber.

To understand fully the chemistry/physics involved, one has to consider Van der Waals forces, cohesive energy density and heat of vaporization of the materials.



The theory behind solubility parameter was proposed by a renowned chemist and scientist, Dr. Joel Henry Hildebrand (November 16, 1881 – April 30, 1983) hence the term "Hildebrand solubility parameter" is often used.