Basell has launched a metallocene-based Metocene polypropylene (PP) copolymer, Clyrell EM248U, targeted for application towards processors of clear, thin-wall, injection-molded (TWIM) food applications in the United States. (The grade was introduced in Europe last year under the developmental name of Clyrell EM1791.)
"Previously, processors have relied upon the need to add plastomers to conventional PP random copolymers in order to achieve the desired impact and clarity for TWIM applications," said Amit Gupta, customer project manager for Basell's Metocene global business unit. Although these blends were capable of meeting performance requirements, the use of the plastomer increased costs and added an extra production step. On top of that, inconsistencies in impact strength from batch to batch increased the chances of having part breakages."
Gupta added: "By using Clyrell EM248U, a lot of the guess work is eliminated from injection molded thin-wall applications because this grade delivers the clarity and stiffness of a random copolymer combined with the impact performance of a heterophasic copolymer - without the need for an additional plastomer."
The grade is produced using an exceptionally clean technology with low levels of volatiles and oligomers. It is a reactor-grade product which does not require vis-breaking or peroxides, and can be used in customer food applications which require low organoleptic properties. "In addition, Clyrell EM248U can be used in in-mold labeling (IML) and off-set printing applications which require consistent impact performance," said Gupta. "Parts made from this new grade are able to withstand the force of an inserted mandrel used during off-set printing, which minimizes the chance that parts will fail and cause lower reject and scrap rates." At a melt flow rate of 70g/10min, the resin offers processing ease with the potential for cycle time reduction without sacrificing part performance. Metocene resins also offer increased resistance to distortion and warpage in injection molding applications.
Clyrell EM248U's high heat deflection temperature also enables it to retain stiffness in customer hot-fill applications. Clyrell EM248U has been previously targeted to European customers for food packaging applications requiring refrigeration and/or freezer impact performance. It is anticipated that U.S. customers will use the material for refrigerated packaging applications for products such as soups, salads and cut fruits.