Scientex has collaborated with ExxonMobil Signature Polymers, Windmöller & Hölscher and Haver & Boecker to develop a polyethylene sack for moisture-sensitive powders, incorporating 30 per cent recycled PE and offering reported weight and material cost savings.
Malaysian flexible packaging manufacturer Scientex has developed a polyethylene (PE) heavy-duty sack for fine powders, combining moisture protection and a self-venting design with 30 per cent recycled PE content.
The VentiFlex form-fill-seal (FFS) sack was developed with ExxonMobil Signature Polymers and German machinery suppliers Windmöller & Hölscher (W&H) and Haver & Boecker. The collaboration brings resin selection and film production together with bag-making and filling expertise.
ExxonMobil reports that the PE-based bags weigh up to 13 per cent less than a reference paper-based sack. An analysis based on annual use of 10 million bags also indicated a six per cent reduction in estimated packaging material costs compared with kraft paper sacks with PE liners.
Containing fine powders
Fine powder packaging must control dust and product loss, protect against moisture that can cause clumping, and allow consistent flow during filling. The partners identified moisture absorption, tearing and powder escaping through seams or small tears as challenges to address in replacing conventional paper sacks.
PE liners can improve moisture protection in multi-layer paper sacks, but the combination of materials can complicate recycling. Scientex sought a PE-based alternative that would provide the required barrier and handling performance.
The partners selected ExxonMobil’s Exceed Tough+ resins for stiffness, toughness and moisture barrier properties. Scientex’s VentiFlex design allows excess air to escape after filling and sealing while, the company says, maintaining protection of the contents.
As the filled sack is flattened, air is pushed into venting channels and released through channel openings. The company says this helps prevent powder loss and maintains a dust-free pack appearance.
Material and machinery performance
The 140-micron PE sack incorporates 30 per cent recycled PE and is designed for loads up to 25kg. ExxonMobil says the material’s mechanical properties enabled the recycled content to be incorporated while meeting the application’s performance requirements.
The partners report improved drop performance compared with a paper sack with a PE liner, alongside flatness and resistance to deformation suitable for filling and stacking. The performance comparison is based on trial observations and market feedback.
The tubular film is described as self-venting and weatherproof, with sealing and durability characteristics suited to building materials and powder products. Other reported benefits include print quality for branding and reduced product losses from moisture ingress or powder sticking to the sack.
Haver & Boecker contributed filling expertise through its ADAMS technology. Bjoern Lindemann, managing director of Haver & Boecker Southeast Asia, said the company was supporting the transition to PE bags.
“We are proud to contribute to this market transition by enabling profitable packaging in weatherproof and tear-resistant PE bags,” Lindemann said.
Cost and recovery considerations
The cost analysis compares a 135g PE sack with a 156g kraft paper sack incorporating a PE liner. Estimated material costs were US$0.30 and US$0.32 per sack respectively, equivalent to US$3 million and US$3.2 million annually at the stated volume.
A general-purpose PE reference sack in the same analysis weighed 186 g and used 200-micron film. The comparison illustrates why resin formulation and bag design are central to the potential savings, rather than a change to PE alone.
The partners describe the mono-material PE sack as designed for recyclability. Actual recycling depends on local collection, sorting and processing infrastructure, as well as the condition and configuration of the film after use. ExxonMobil notes that facilities accepting and processing plastic film are not widely available.
