Water-Dispersible Adhesive Raw Materials, 1996 Hot Melt Symposium Proceedings

Repulping of paper products has created a need for hot-melt adhesives that are water-dispersible. Eastman Chemical Company has developed a family of branched, waterdispersible polyesters suitable for formulating aqueous dispersions as well as hot-melt adhesives for packaging, nonwovens, and other uses. Available in a range of viscosities, these materials offer the following key features when formulated into hot-melt adhesives: l 100% water-dispersible in ordinary tap water at room temperature overnight. Conventional formulations are nondispersible. l Nondispersible in ionic solutions (i.e., body fluids). Competitive water-dispersible technologies are not ionic by nature and are likely to exhibit some degree of solubility in saline solutions. l Superior adhesion to polyolefin films. Hot-melt adhesives based on these branched polyesters have from 10% to 110% better adhesion to PE and PP than typical conventional formulations. Some conventional adhesives do not adhere to polyolefins. l Key physical properties comparable to conventional formulations. Characteristics, such as Tg , softening point, elongation, shear adhesion failure temperature and peel adhesion failure temperature, are comparable to those typical of conventional hot-melt polymers. The purpose of this paper is to discuss these new, branched polyesters as raw materials for hot-melt adhesives that are water-dispersible and to review the experimental process by which they were optimized.