Bimodal HDPEs suit demanding blown film applications
By Barry Copping
Posted 6 July 2012
HDPEs are designed for acceptable gauge tolerances with adequate stiffness and strength at very low thicknesses
Sabic has announced a family of bimodal high-density polyethylenes (HDPE) for the production of high-quality thin blown film.
The standard grade is HDPE FI0644, and a higher-density grade with grater flow is HDPE FI1157.
Both grades have high molecular weight and a broad molecular weight distribution. These characteristics translate into a good processability which will minimise disruptions during film production, says Sabic, combined with good mechanical properties in the blown film. The low gel levels lead to consistent film production and a smooth film surface. Film makers can achieve acceptable gauge tolerances with adequate stiffness and strength at very low thicknesses, according to the company, and both grades can be processed at temperatures around 10% lower than common HDPE grades.
Krzysztof Rozensal, PE technical marketing engineer at Sabic, says “The balanced properties of the grades are key to attaining a consistent, reliable and efficient film production process. In particular, FI1157 can be processed at high speed while maintaining a robust bubble stability, maximising film output and minimising energy consumption.”
Typical applications for FI1157 are the production of lamination films, release films, inliners, labels and artificial paper. Sabic claims an impact resistance around 20% higher than films made from a typically common HDPE grade.
Sabic FI0644 is designed for applications requiring extra strength, such as heavy-duty bags, inliners, meat bags, grocery sacks and carrier bags.
Films made with both resins exhibit a strong combination of stiffness and tear resistance, says Sabic. FI1157 films, for example, have an Elmendorf tear resistance at least 30% higher than films made from a common HDPE grade. Rozensal says “These properties make FI0644 and FI1157 the materials of choice to meet continuously growing market challenges.”
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