Method of joining plastic sheet materials

摘要

A method of joining thin plastics film or sheet materials to form sealed pressure vessels or containers particularly vessels or containers for use in the medical industry such as blood or urine bags. Experience has shown that there is a wide distribution of working life to failure for commonly used bladder materials due to fatigue stress to the area adjacent to the weld joining the sheet materials together resulting from radio frequency welding which is a common prior technique. In the present invention an more accurate controllable and repeatable method using is disclosed using the plastics injection moulding technique which uprates below the melting points of the materials to be joined thus avoiding early failure due to material degradation caused by the radio frequency welding.