Aluminum-Polyethylene Laminates Formed in High Vacuum

Abstract The bonding of LDPE to Al in high vacuum (10−5Pa) was studied using a special apparatus that allowed the degassing at 200 C of each material prior to the application of mechanical pressure The results were compared with those obtained from samples bonded in air. Laminates formed from extruded LDPE and untreated Al in vacuum had higher initial peel strengths (13 Ncm−1) than laminates formed in air (6 Ncm−1) indicating the importance of volatiles, such as water, in the bonding process. Subsequent exposure to warm, moist air essentially negated the effect of the vacuum. The higher peel strengths generally obtained with extruded films when compared to samples made from other forms of the same LDPE resin, i.e., as received pellets or pressed films, were attributed to the oxidized species produced during extrusion. Higher peel strengths were also obtained when the Al was boiled for 10 minutes in water prior to lamination to PE pellets, 10 Ncm-1 as contrasted to 1–2 Ncm−1 for untreated Al.