Screening of Hot Melt Components for Repulpability Using a Four Step Test That Considers Common Repulping Environments, 1993 Polymers, Laminations & Coatings Conference Proceedings

The repulpability of a noncellulosic material may be defined as the compatibility of that material with paper and/or paperboard recycling processes. The degree of repulpability of noncellulosic materials, such as hot melt adhesive components, depends on such factors as dispersibility in neutral and/or alkaline aqueous conditions, and component density. This paper initially describes a four step screening method developed to screen the repulpability of hot melt raw materials and finished adhesives or coatings using three common repulping environments and common or easily modified laboratory equipment. In steps 1 and 2, hot melt material behavior in neutral and alkaline aqueous repulping environments is investigated. Step 3 involves the calculation of a dispersibility factor (DF) to quantify dispersibility. Step 4 investigates hot melt material behavior based on density. This four step method is loosely based on several previously published procedures as well as advice from the paper coating and recycling industries.

In addition, this paper outlines work that investigated the repulpability of three families of hot melt adhesive base polymers and simple blends using the four step procedure described. The materials evaluated were subjectively rated for repulpability under neutral and alkaline aqueous conditions, assigned dispersibility factors (DF) to quantify dispersibility, and tested for removability based on material density.