PETpla.net Insider 07+08 / 2021

BOTTLE MAKING 27 PETplanet Insider Vol. 22 No. 07+08/21 www.petpla.net respect to a reference is vital — this is the principle of Blowscan. The differ- ence in blowing behaviour is quan- tified and a verdict on the preform condition can be made. Additionally, with the mould kit, the operator is able to test the desired bottle design while maintaining the same heating and blowing parameters. This allows for rapid bottle prototyping without inter- rupting the production lines. Who benefits? Blowscan is claimed to offer a number of benefits across all sectors of the supply chain. Through the use of the instrument, material produc- ers can quickly and efficiently assess the blowing potential of novel mate- rials, without the need for cumber- some industrial equipment. Preform manufacturers can identify the quality of preform batches as they are pro- duced, which in turn provides con- verters with confidence. Finally, both converters and brand owners have the added benefit of producing small runs of bottle prototypes without inter- rupting production. Case studies Case study 1 – Recycled material type Blowing geometry (rPET and flake) Case study 2 – rPET content For this case study, an investiga- tion was conducted for PepsiCo to examine the difference in blowing behaviour between different rPET resins, by varying the post-consumer resin (PCR) percentage. Virgin, 25% PCR and 100% PCR preforms were analysed using Blowscan. Effect of PCR increase on blowing behaviour relative to virgin As the % PCR content was increased, there was a significant change in the blowing behaviour for both IR and oil bath heated preforms. The 100% PCR preform demonstrated a 31.9% and 27.2% shift in blowing capability for oil bath and IR heating, respectively, when compared to virgin preforms. This indicated that, in this instance, the increase in PCR mate- rial influences both the mechanical properties and optical properties of the preform, and as before, a change in blowing behaviour will result in a change in bottle performance. Know- ing how a change in material com- position (be it PCR content, amount of additives, colour, preform age, moisture etc) influences the blowing behaviour allows the user to make informed decisions as to how best to implement the blowing process and ultimately, benefit production. PepsiCo’s Max Rodriguez, Sr. Manager, Global Packaging R&D, concluded, “BMT compliments Pep- siCo’s Global Packaging R&D’s inter- nal capabilities, by providing structural FEA support, SBM PET material char- acterisation, and package develop- ment research collaboration. The Blowscan unit will allow us to expand our internal capabilities across several areas, including packaging innovation, sustainability, productivity, and brand stewardship. www.bmt-ni.com Working with Logoplaste Innova- tion Lab, BMT’s Blowscan was used to investigate the difference in blow- ing behaviour between rPET preforms manufactured from resin and from flake. Logoplaste Europe R&D Direc- tor, Francisco Alves, stated, “At the end of 2019, we challenged BMT, with Logoplaste’s assistance, to develop a lab version of their Indicate machine to use as a quality control and develop- ment tool. This allowed us to address characterisation needs that we can’t meaningfully access today with con- ventional characterisation techniques”. The preform geometry, heating conditions (oil bath and IR) and blow- ing parameters were fixed for both materials. From the trials, the preform temperature, inflation pressure and blowing geometry (via edge detection) were analysed. Oil bath trials revealed that there was no difference between the mechanical properties of the two preform types. However, the IR heat- ing process produced two different temperature profiles and as a result, the blowing geometry exposed a differ- ence in blowing behaviour. The result of the ‘hotter’ rPET preform during IR heating was a free-blow bottle that had a 12% larger deformation. In addition, the increased temperature created an earlier onset of deformation by 30ms. In a process that takes a fraction of a second, this can be significant for the bottle properties, particularly material distribution and as a result, the in- service performance. Blowscan was used to examine the change in material properties and quantify the shift in process para- meters required to produce the same blowing behaviour as the reference preform. In this study, a 5% oven power increase allowed the flake pre- form to blow with the same behaviour as the rPET preform. This finding is vital for bottle production when imple- menting new materials and identifying an appropriate process window. Alves summarised, “This equip- ment will be a strong complement on the preform quality control plan for our operation’s most challenging applica- tions. This will improve our ability to link new preform and bottle designs to material properties, allowing higher efficiencies, enabling lighter weights and providing more sustainable solu- tions to our customers.”