Thermoplastic Copolymer
Synthetic resin polymers synthesized from ethylene and vinyl acetate monomers provide adhesive bonding, heat sealability, and barrier coatings across packaging formats. Extrusion and hot-melt formulations utilize ethylene vinyl acetate to create fast-setting adhesives for carton erection, case sealing, and flexible film lamination. The vinyl acetate percentage governs flexibility, optical clarity, polarity, and adhesion to diverse paper surfaces, with higher proportions lowering seal initiation temperatures while increasing bond tackiness.
The material exhibits thermal degradation when exposed to prolonged holding temperatures above two hundred degrees Celsius.
Processing Behavior
Converting plants run hot-melt formulations containing this copolymer through automated nozzle applicators at line speeds exceeding three hundred cartons per minute. Viscosity drops predictably under elevated melt tank temperatures, permitting controlled bead deposition without stringing or tailing. Open times range from half a second to five seconds, allowing packaging lines to achieve rapid green strength before cartons discharge from compression sections.
Repulping Effect
Standard mechanical recycling pulpers do not dissolve synthetic copolymer adhesive beads during ambient temperature water re-slushing. Fragmented adhesive particles form tacky micro-stickies that foul forming fabrics, contaminate press felts, and cause web breaks on paper machines. Mill screening systems with fine slotted screen baskets must remove these particulates before they reach the paper machine headbox.
