Stora Enso Oyj

Sami Kotkamo

Kimmo Nevalainen

Jurkka Kuusipalo

Tapani Penttinen

Tapio Koskinen

Ville Ribu

Jari Räsänen

Outi Kylliäinen

Ari Rosling

Mohammad Khajeheian

Mikko Tuominen

Mikko Touminen

A method for improving the heat sealability of a packaging material and a method for manufacturing a heat-sealed container or package are described. The material can be polymer-coated packaging paper or cardboard, or a polymeric packaging film. The material includes a polymer layer that contains polyester, particularly polylactide, the heat sealability of which is improved by ultraviolet radiation. Polylactide is useful as such or when blended, for example, with other biodegradable polyester. The containers and packages thus manufactured include disposable drinking cups and cardboard carton and box packages.

Method for improving the heat sealability of packaging material and method for manufacturing heat-sealed container or package

The invention relates to methods for lowering the melt viscosity and thereby improving heat-sealability of a polyester. The invention also relates to a method for manufacturing a heat-sealed container or package from fibrous-based, polyester-coated packaging material, and a method for heat-sealing polyester. The solution according to the invention is subjecting polyester to electron beam (EB) radiation. The lowered melt viscosity allows a lower heat-sealing temperature, and permits sealing of polyester to an uncoated fibrous surface. The preferred polyester for the invention is polylactide, as such or as blended with another polyester.

Methods for lowering melt viscosity and improving heat-sealability of polyester and for manufacturing a heat-sealed container or package

A biodegradable packaging material, a method of manufacturing the same, as well as products made of the material wherein a multilayer coating coextruded onto a fibrous substrate the multilayer coating comprising innermost and outermost layers of a blend comprising 20-95 wt-% of a higher melt index polylactide and 5-80 wt-% of another biodegradable polymer such as polybutylene succinate, and a middle layer containing a lower melt index polylactide alone. The goal is to increase machine speed in coextrusion while maintaining good adhesiveness to the substrate and good heat-sealability of the coating. The products include disposable drinking cups and board trays, as well as sealed carton packages for solids and liquids.

Method for manufacturing biodegradable packaging material, biodegradable packaging material and packages and containers made thereof

A heat-sealable biodegradable packaging material, its manufacturing method and a product package formed thereof, where the packaging material comprises a fiber substrate, an inner polymeric coating layer against the fiber substrate, which contains polylactide and a biodegradable polyester that is blended therewith to improve the adhesion between the inner coating layer and the fiber substrate, and an outer coating layer that constitutes the outer surface of the material and contains polylactide and a biodegradable polyester that is blended therewith to improve the heat sealing ability of the layer, the portion of polylactide in the inner layer present in an amount greater than that in the outer layer. The inner and/or outer coating layers can further have blended therewith a small amount of acrylic copolymer that improves the adhesion and/or heat sealing ability. The coating layers can be introduced onto the fiber substrate by extrusion or coextrusion.

Heat-sealable biodegradable packaging material, a method for its manufacture, and a product package made from the material

Growing community of inventors

Tampere, Finland

Sami Kotkamo