New twist makes stronger cross-laminated film.

A new helically cut, cross-laminated HDPE film from Ole-Bendt Rasmussen, inventor of tear-proof Valeron films in the 1950s, starts out as blown film that is slit into layflat and longitudinally stretched and embossed with intermeshing grooved rollers that leave thin parallel lines. The roller grooves are squared, so the film thins out on the sides of the grooves and is thicker at the tops and bottoms of the grooves. The result is film with thick and thin MD stripes like corduroy fabric, three stripes per millimeter of width (see photo).

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This striped film is then helically cut, turning the stripes at a 60[degrees] angle to the film MD. The bias-striped film is then continuously stretched sideways between two "sectional rollers" with reciprocating sections that slide out and back in during each revolution. Roller sections grip and pull the film as they slide out, then release the film and slide back. This further stretches the embossed stripes and turns them another 30[degrees] so that they face in the transverse direction. TD-striped film can be laminated to the original MD striped film to make film with higher yield strength (up to 150 MPa, or 21,750 psi), plus greater tear resistance and impact strength than previous cross-laminations.

O-B R Enterprise in Walchwill, Switzerland, introduced the technology last fall at the SPF 2006--Specialty Plastic Films Annual World Congress in Dusseldorf, Germany, organized by Maack Business Services in Zurich, Switzerland. O-B R has made cross-laminated film up to 40 cm wide and plans trials up to 1 meter-wide this year at licensee Supreme Industries Ltd. in Mumbai, India. O-B R: [phone]/www.xf-plasticfilms.com * Maack: [phone]/www.rnbspolymer.com