FIELD: composite materials.
SUBSTANCE: invention is related to composite materials for food packaging and concerns a composite film for producing sealing lids. Composite film (1) for producing sealing lids with an aluminium layer (2) contains a multilayer extrusion layer (3) applied by coextrusion onto an aluminium layer (2). The extrusion layer (3) contains a sealing layer (6) and an adhesion promoter layer (5) located between the sealing layer (6) and the aluminium layer (2). The sealing layer (6) contains a polymer matrix with at least the first polymer component and the second polymer component, and an additive that increases the peeling force, in particular a mineral filler, for example talc, is added to the polymer matrix of the sealing layer (6). The first polymer component is chosen to be polyolefin, and the second polymer component is chosen to be polyolefin thermoplastics and/or polyolefin elastomers with a bulk density below 900 kg/m3, as well as combinations of such materials.
EFFECT: invention ensures the production of aluminium sealing lids with improved recyclability, the proportion of polymer material in which can be reduced, and at the same time plastic can be extruded onto an aluminium layer, and also makes it possible to significantly reduce the thickness of the extrusion layer while maintaining high line speed and at the same time can achieve good and constant strength of the sealing seam.
15 cl, 1 dwg
