Thin film composite technology

Multilayer composite films or multilayer composite materials of films and aluminum foil and paper have been significantly improved in terms of air barrier, heat sealing, printability, peel strength, hygiene and economic rationality compared with single-layer packaging materials. Therefore, they are increasingly used in the packaging field to replace traditional metals, glass, wood and paper. The composite methods are as follows:

(1) The hot-melt composite uses EVA based hot-melt adhesive or microcrystalline wax as the adhesive. When using, it is melted into a fluid by heating in a constant temperature bath, quantitatively coated on paper, compounded with aluminum foil, etc., and usually used as a beer trademark, etc

(2) Wet lamination is commonly used for laminating aluminum foil and paper. The adhesive also contains solvent when the composite is completed. One side of the substrate is loose and has few holes, which is breathable. The solvent is completely volatilized in the drying room, so the substrate used in this method is selective. The adhesive for wet lamination is represented by vinyl acetate emulsion, and the adhesion fastness is in direct proportion to the amount of adhesive coating and solid content. At present, wet composite materials are mainly used for packaging cigarette boxes, labels and dried fruits.

(3) Dry compounding

(4) Extrusion coating

(5) Coextrusion compounding