PETpla.net Insider 07+08 / 2019

PREFORM PRODUCTION 15 PET planet Insider Vol. 19 No. 07+08/19 www.petpla.net PREFORM PRODUCTION 15 Preform storage length / conditions can cause PET bottle performance issues An issue of age www.sacmi.com SACMI manufacturing technology: the advanced solution,from single machines to complete lines Product design Product development Product validation Industrial production plant Process & quality control On-site and start-up assistance After-sales and Customer service SACMI 4.0 THE COMPLETE CLOSURE, PREFORM AND CONTAINER SOLUTION FOR YOUR SMART FACTORY Your Smart Factory will be child’s play. sculpture by Antoine Geoffrion / bottlerobot.com Products created using SACMI compression technology can be made from PCR polymers too. Proprietary research from PTI shows that PET bottle performance issues may have their root cause in how long preforms are stored and in what environment. “Our plant support personnel were frequently being asked what storage duration was acceptable for preforms and what problems can present them- selves during longer storage periods,” explains Sumit Mukherjee, chief technology officer, PTI. “With almost 40 years of experience in this area, we knew that the longer the preform is stored, the greater the impact on performance—particularly if that preform was stored in a high-humidity environment.” To get specific answers to the question, PTI stud- ied 2 liter and 20-ounce preforms that were more than a year old. These preforms were dried under vacuum at 40 °C to get them back to a condition similar to when they were first moulded. The short answer is that preforms stored three, six or 12 months, respectively, will each process differ- ently. The older the preform, the more difficult it will be to processing so that the container meets performance criteria. The time of year the preforms were injection moulded, along with the environmental conditions in which they are kept, will also impact performance. Additionally the study found a diminishing mois- ture egress rate with time from a drying perspective, that wet preforms absorb more heat under the same process conditions, that moisture is more impactful on the properties of larger diameter preforms, and that drier preforms stretch less. The finding also include that moisture acts as a plasticiser, allowing for more stretching and lesser strain hardening. www.pti-usa.com