METHOD FOR IMPROVING HEAT SEALABILITY OF PACKAGING MATERIAL AND METHOD FOR MANUFACTURING HEAT-SEALED CONTAINER OR PACKAGE

The invention relates to a method for improving the heat sealability of a packaging material and a method for manufacturing a heat-sealed container or package. The material can be polymer-coated packaging paper or cardboard， or a polymeric packaging film. According to the invention， 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 manufactured according to the invention include disposable drinking cups and cardboard carton and box packages. The invention relates to a method for improving the heat sealability of a packaging material and a method for manufacturing a heat-sealed container or package. The material can be polymer-coated packaging paper or cardboard， or a polymeric packaging film. According to the invention， 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 manufactured according to the invention include disposable drinking cups and cardboard carton and box packages.