Aluminum foil is often combined with paper or various film substrates by extrusion coating or lamination. LDPE is frequently used to adhere these substrates to the aluminum foil for dry food and other packaging applications, but the adhesion levels are often marginal and inconsistent.

We developed a modifier to enhance the adhesion performance of LDPE. Blends of up to 20% of the adhesion enhancing (AE) modifier into LDPE substantially improve the bond strength to foil. The level of performance depends on the processing conditions. Statistically designed experiments show that adhesion increases with increasing percent of modifier in the blend, temperature, thickness and time in the air gap.

The results show that the modifier offers several benefits to flexible packaging applications, including greater consistency in meeting adhesion specifications and the ability to run at faster line speed or at lower temperatures without sacrificing adhesion. These are demonstrated using statistical modelling and analysis. In one converting trial, adding the AE modifier improved the yield from 4% to 99%.