| 摘要 |
In a method for the heat-sealing or welding of a surface consisting of an olefinic polymer to a surface consisting of a polar synthetic or cellulose material, the surface consisting of the olefinic polymer is firstly subjected to a corona treatment and the surfaces are subsequently joined under heat and pressure. Apparatus for closing containers or bags having surfaces of the aforedescribed materials, comprises conveying means for the containers or bags, sealing jaws for effecting the heat-sealing, and a corona for treating at least one of the sealing surfaces located upstream of the sealing jaws. The jaws may be heatable or may heat seal ultrasonically. Specified olefinic polymers are polyethylene, polypropylene and copolymers of ethylene or propylene with vinyl acetate or acrylic acid ester. The polar surface may consist of a polymer based on vinyl acetate or vinyl chloride, polyester, e.g. polybutylene terephthalate, or paper or cardboard with or without laquer or a pigment coating. |
