Austria: BSW Machinery has presented a new type of woven polypropylene (PP) bag that is 20% lighter than comparable bags. Using its Light & Strong (LS) technology BSW has produced 64g bags that they say outperformed standard 80g bags commonly used in the cement industry in drop tests. Key elements of the LS technology include advanced extrusion technology for higher tape tenacity and indexed micro perforation.
The Vienna-based subsidiary of Windmöller & Hölscher has implemented new processing technology on BSW's tape extrusion line tiraTex to achieve higher strength without compromising elasticity. Tenacity values of 7g/den can be achieved with elongation at break values ranging be-tween 25% and 30% using standard PP grades commonly used in industry. The processing characteristics can be maintained at high outputs and production speeds of 500m/min or more.
The LS bags also have higher edge strength by protecting edges and other areas through indexed perforation. The perforation is disengaged whenever vulnerable sections of bag material are passing through the bag conversion machine. Synchronization ensures that the unperforated areas are matched to the print on the bag and are placed such that in the final bag the critical zones are built from un-perforated material.
