PP boosts clarity, withstands steam sterilizationPP boosts clarity, withstands steam sterilization
Borealis has introduced a number of new materials offering increased film functionality. Among them is a new grade of Borclear, designated Borclear RE936CF, that targets highly transparent PP cast-film processing.
February 6, 2009
eweekly_Jan2_LeistritzBorealis has introduced a number of new materials offering increased film functionality. Among them is a new grade of Borclear, designated Borclear RE936CF, that targets highly transparent PP cast-film processing. According to Nina Ackermans, application marketing manager for film and sheet, the new grade is a random copolymer only now entering commercial supply as part of the supplier’s Berghausen, Germany site expansion. The film’s haze is less than 2-3% even after steam sterilization at 121°C for 30 minutes, compared to about 10% for most cast PP films after similar conditions. Film extruded to a thickness of 50 µm has a gloss of 142%, she added. Of most significance for plastics processors, she said the material has been tested on an extrusion line from Austria’s SML and was run at 450 m/min. For this testing, a 20-µm thick coextruded film was processed with the new grade in the center of a 20/60/20 construction. “We didn’t change anything on the line, and we were able to raise the film line speed from 350 to 450 m/min, with better clarity, gloss, and lower haze,” she said. The film’s haze was just 1.6%, with a gloss of 118%, and clarity of 96.4. The photo, left, shows a typical application.
Also of potential interest to flexible packaging processors is the supplier’s new impact copolymer PP, dubbed Borpact BC918CF and said to be suitable for processing on both cast- and blown-film lines, as well as able to boost film’s stiffness and toughness simultaneously. The material also is said to thermoform well, so that Ackermans surmised it could see use both as the cast-film extruded/thermoformed trays, as well as in blown-film extruded lidding film for applications such as modified atmosphere packaging (MAP) trays. Other potential applications are in laminate films for standup pouches and label films. The material brings a flexural modulus greater than 1000 MPa, but with haze of less than 10% and impact strength of 10-25 J/mm. Ackermans said films run using the material have realized 30% higher stiffness and toughness.—[email protected]
Borealis AG, Vienna, Austria; +43 1-22-400-302; www.borealisgroup.com
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