| 摘要 |
The invention relates to a heat-sealing method, in which a polymer material (1) forming the seal is melted or softened with an air flow (4) blown to the sealing point (11). In accordance with the invention, water (7, 9) is added to the air flow in order to increase the moisture content of the hot sealing air. The air is heated by resistance heating or flame heating and the water can be introduced in the hot air flow in the form of water, which subsequently evaporates, or in the form of water vapour. The method is suitable i.a. for producing packaging containers by sealing polymercoated paper or board. |
