| 摘要 |
The method makes flat, sealed joins between layers of flat, flexible material, esp. packaging, without a prim. heat supply. The materials (2) are sealed by treatment of the contacting surfaces with ultrasound, under pressure acting at right angles to them. Pref. the material is non expanding and easily combustible, esp. paper. It has a coating which can be welded as above. The ultrasound joins it with a compatible, or compatibly-coated layer. Suitable materials include 60-80 g/m<2> paper, coated with 15-20 mu m of polyethylene, or 20 mu m of polypropylene. Ultrasound at 20-40 kHz is used with a sonotrode tip 300-130 mm in length, and a pressure of 30-40 kp/cm<2>. |
