INNOVATION | THIN WALL MOULDING


IMAGE: SABIC/NETSTAL


Above: The benefits of using injection compression moulding are highlighted by SABIC and Netstal


Berry Superfos and Repsol which supplied the recyclate. “Our partnership with Choví is an example of the kind of relationship that we strive to establish with all our customers every day,” says Berry Superfos Iberia’s Commercial Director, Ignacio Igea. “It involves being innovative and providing state-of- the-art technology, dedicated service and commit- ment to more sustainable development.” The current climate has led to more collabora- tions between partners occupying different spaces in the value chain who come together to share their expertise or resources in the hope of making mutually beneficial advances. One example is SABIC and Netsal setting up a


Thin Wall Application Centre at the latter’s facility in Näfels, Switzerland, where the two companies are combining their knowledge of complementary materials, processing, and injection compression moulding (ICM), in a concerted attempt to apply this proficiency to thin-wall packaging. ICM is a process where the melt is injected into


a still-partially open mould. Final forming takes place after complete closing by displacement of the melt into the cavity. This enables the mould to be filled under lower pressure, which in turn leads to a reduction of warpage. The technique facilitates the production of extremely thin, precisely repro- ducible wall thicknesses and accurate reproduction of surface structures. The joint initiative opens significant opportunities


Right: Computer image of thin wall container produced with recycled PET by Engel at K2022


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for further down-gauging and lightweighting at lower injection pressures, using reduced clamp forces, and leading to shorter cycle times, all of which helps meet increasingly stringent regulatory, brand owner and consumer requirements.


INJECTION WORLD | March 2023


Although ICM has become a common technology in automotive and optical applications, its translation to thin-wall packaging is challenging mainly due to the differences in material types and machine setups required to address the vast diversity of applications and part geometries involved. Nevertheless, trials at the Thin-Wall Packaging Application Centre have been encouraging and demonstrated significant benefits when the process is used with the proper materials, along with optimised mould and applica- tion design. For example, in the case of an airline cup, it was found that the injection pressure can be decreased by up to 50% compared to injection moulding, resulting in thinner wall thickness and a potential weight reduction of 20% (see box left). SABIC and Netsal say that ICM offers enormous potential for weight, material, energy and cost saving when applied to thin wall packaging, and their partnership demonstrates that the transfer and implementation of this technology can be accelerated when value chain partners combine their strengths. Another collaboration to benefit the packaging industry was unveiled at K2022 where, in co-opera- tion with partners Alpla Group, Brink and IPB Printing, Austrian machine manufacturer Engel showed how thin-walled containers made of PET with recycled content can be produced in a single process using its E-speed injection moulding machine.


Until now, it has only been possible to process


PET in thick-walled parts, but the new containers boast a wall thickness of 0.32 mm and a volume of 125 ml. Integrated in-mould labelling (IML) means that the containers are ready for filling as soon as they leave the production cell. Engel says the dyes used on the labels for the American market can be washed off prior to recycling, while IMLs used in the European market detach in the recycling process, allowing the label to be separated from the PET container. This provides an opportunity for bottle-to- bottle, bottle-to-cup, or even cup-to-bottle recycling. The European Commission requires all plastic


packaging to contain 30% recycled material and be 100% recycling capable by 2025. However, experts suggest this will be difficult to achieve given that polyolefins and polystyrene are com- monly used in rigid


G E : E N G www.injectionworld.com


packaging food applica- tions. So rPET offers a solution for avoiding penalties and additional taxes and although the price of PET is comparatively high,


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