Scientex, a leading player in flexible plastic packaging with headquarters in Malaysia and plants in Malaysia, Vietnam, Myanmar, and the US, had been testing various solutions for its machine-orientation direction (MDO) films for some time.
In MDO film production, a polymer is heated to a temperature slightly below its melting point and stretched in a particular orientation. Stretching film in machine direction accentuates its properties many times over and makes two or three times more products with the same amount of plastic. However, the MDO process is highly demanding as the stretching operation to make thin films requires an easy-to-process resin with low gel, good bubble stability, and low melt pressure characteristics to prevent intermittent production stoppage or turbulence.
For Scientex and other film manufacturers using MDO technology, process stability is critical and key to maximizing production rate and minimizing production wastage. Scientex was looking for a solution that reduces gel and film breakage, which is the main issue faced during the MDO process, as well as maintains good stiffness, toughness, and optical properties in the MDO films.
Solution
Knowing the requirement from Scientex with its MDO film, the ExxonMobil team introduced Scientex to its latest polyethylene, Exceed S, before it was commercially available in April 2022. Scientex was one of the first in the world to trial and test the new resin in their MDO film.
After intensive and prolonged trials, Scientex knew they had found a solution by using Exceed S 9243. The Scientex team was impressed by the Exceed S 9243 trial results. They found they could run the Exceed S MDO solution continuously without much issue. The start-up was easy; the operation was smooth with no time wasted on any film breakage. Processing stability featuring good melt strength, excellent bubble stability, acceptable melt pressure, and less gel in the film resulted in significant cost savings to Scientex from a reduction in film wastage and man-hours, the company said.
The team was also impressed with the significant boost to stiffness and high tear performance they saw with the Exceed S solution. Yong Chee Ming, Scientex Great Wall general manager, said: “The key advantage of Exceed S is process stability with good melt strength and bubble stability during the extrusion process. We have achieved much better yield in the MDO process due to improved stretchability, lesser gels, and better stiffness compared with our existing film”.
Results and gains
Stiffness is a critical requirement in MDO film as it allows Scientex to market its MDO films more competitively against traditional PET or other oriented non-PE-based laminates. Currently, flexible packaging films are mostly composite laminates comprising a PE sealant film with PA/PET substrate films. These multi-material structures can be difficult to recycle with mechanical processes. A PE-based MDO film can replace PA/PET substrate films to make full polyethylene packaging suitable for liquid and solid contents.
By combining state-of-art converting technology from Scientex with an innovative Exceed S platform from ExxonMobil, both companies are pushing the boundaries of MDO full-PE packaging design by offering mono-material packaging solutions with sustainability benefits. Due to successful trials and Scientex’ confidence in the new Exceed S MDO solution, they are leveraging it in end applications such as frozen food packaging, stand-up pouches for shampoo, detergent, and pet food and glove packaging.
