TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: Other alpha -olefins used as comonomers in component (A) are propylene, 1-butene, 1-hexene, 1-octene or 1-decene; preferably, (A) has an ethylene content of 90% or more and shows a density of more than 0.92, preferably more than 0.93. Function (X) may be a maleic anhydride group or a glycidyl methacrylate group. The composition (I) contains 10-75 wt.% component (A) and may also contain another polyolefin (C) (different from A and B) with a function (Y) capable of reacting with (X), preferably with a mol ratio of X/Y = 0.3-4.5. Component(s) (A) and/or (B) and/or (C) contain ethylene units, and (B) is preferably a copolymer of ethylene, alkyl methacrylate and maleic anhydride. (I) may also contain additives such as coupling agents, crosslinkers, UV absorbers, mineral fillers, plasticisers, coloring agents, optical brighteners and fire retardants.Preferred Method: The film is made by extrusion at 115-140 degrees C and stoving is carried out at 140-200 degrees C. EXAMPLE - A mixture of 12.5 wt.% Lotader AX8840 (RTM: ethylene-glycidyl methacrylate copolymer; m.pt. 106 degrees C), 37.5 wt.% Lotader 6200 (RTM: ethylene-ethyl acrylate-maleic anhydride terpolymer; m.pt. 102 degrees C) and 50 wt.% M 3410 EP (RTM: medium-density metallocene-polyethylene; density 0.934; m.pt. 124 degrees C) was processed in an extruder and extruded at 125 degrees C to form film with a thickness of 0.5 mm. The product showed a moisture vapor transmission rate (DIN 53122, Method E) of 8 (400) g.25 micron/m2/24 hours and a peel strength (ISO 8510-1; at 90 degrees C using a glass/film/backsheet system) of 37 (2) N/15 mm (with adhesive failure and delamination of the backsheet). Values in brackets are for ethylene-vinyl acetate (EVA) copolymer (33% vinyl acetate). Flow tests under load at increasing temperatures were carried out on test pieces made by pressing for 20 minutes (a) at 125 degrees C or (b) at 160 degrees C; samples (a) showed no elongation after 15 minutes at 115 degrees C but broke after 7 minutes at 125 degrees C; samples (b) showed similar behaviour up to 115 degrees C, followed by an elongation of 120% at test temperatures from 125 degrees C to 155 degrees C, without fracture. In flow tests with EVA, both types of samples (a and b) failed in less than 1 minute at 85 degrees C.