A composite sheet material includes a cover sheet, a substrate and an adhesion promoting layer. The cover sheet has a cover sheet material. The substrate has a substrate material. The adhesion promoting layer is disposed between the cover sheet and the substrate. A first side of the adhesion promoting layer disposed towards the cover sheet has an affinity to bond with the cover sheet material. A second side of the adhesion promoting layer disposed towards the substrate has an affinity to bond with the substrate material.

The present invention relates to a heat-sealable structure comprising an aluminum foil and a heat-seal lacquer, said structure exhibiting a seal strength, according to ASTM F2824, of more than 23 N/15mm when heat- sealed to another heat-sealable structure comprising an aluminum foil and the same heat-seal lacquer, the heat-seal lacquers of both structures contacting each other for heat sealing, said seal lacquer comprising a copolymer blend comprising: - from 30 to 80% by weight, preferably 40 to 70% by weight, more preferably from 50 to 60% by weight of a copolymer A based on (meth)acrylate ester (co)polymers, olefm (co)polymers and block or grafted copolymers comprising (met)acrylate ester sequences and olefm sequences, - from 20 to 70% by weight, preferably 30 to 60% by weight, more preferably from 40 to 50% by weight of a copolymer (B) based on vinyl halides, vinyl esters of carboxylic acids and ethylenically unsaturated (poly)carboxylic acids.

A composite sheet material includes a cover sheet, a substrate and an adhesion promoting layer. The cover sheet has a cover sheet material. The substrate has a substrate material. The adhesion promoting layer is disposed between the cover sheet and the substrate. A first side of the adhesion promoting layer disposed towards the cover sheet has an affinity to bond with the cover sheet material. A second side of the adhesion promoting layer disposed towards the substrate has an affinity to bond with the substrate material.

Hot melt adhesive including a polar group-containing olefin copolymer has: number average molecular weight (M.sub.n) between 10 to 50 kg/mol, crystallinity (X.sub.c) content below 30%, enthalpy (H) between 5 to 65 J/g, polydispersity index (PDI) from 2 to 6, melting temperature (T.sub.m) between 40 and 120 C., and including at least 80 mol % of a constituent unit of formula (1), optionally a constituent unit of formula (2), and between 0.1 to 1 mol %, of a constituent unit of formula (3): ##STR00001## wherein R.sup.1 is H or CH.sub.3; R.sup.2 is a hydrocarbyl group having 0 to 10 carbon atoms; R.sup.3 is a hydrocarbyl group having 2 to 10 carbon atoms, when X is hydroxyl functionality or a hydrocarbyl group having 0 to 10 carbon atoms, when X is polar organic group containing at least one carboxylic acid functionality and 0 to 6 carbon atoms.

A composition contains (A) an ethylene/a-olefin copolymer having a density from 0.855 g/cc to 0.895 g/cc and a melt viscosity, at 177 C., from 5,000 mPa-s to 50,000 mPa-s; (B) a functionalized propylene-based polymer containing from 1 wt % to 10 wt % functional groups, the functionalized propylene-based polymer having a melt viscosity, at 190 C., from greater than 10,000 mPa-s to 50,000 mPa-s and a weight average molecular weight, Mw, greater than 30,000 g/mol; (C) a tackifier; and (D) a wax.