HP, Inc has a corporate edict to use 30% Post-Consumer Recycled (PCR) plastics in personal system and print products by 2025. Plastic bottles are made for the sale of ink for HP printers, and injection stretch blow molding (ISBM) has been the chosen process for bottle production due to the need for detailed threads and thick wall sections. Suppliers make specific virgin plastic grades for ISBM, typically with an MFI between 2 and 10 g/10min. With the addition of PCR, the choice of grade and type of PCR added becomes more complicated. MFI is often the only tool used to make that choice, but it is only a single data point on shear viscosity at very specific conditions of temperature and flow rate. With PCR blended formulations, there is a widening of the molecular weight distribution, changing the flow properties of the material, specifically, the elasticity which is particularly important in blow molding applications. The elasticity of virgin grades, commercial PCR grades, commercial PCR blends, and blends with recovered ocean and agricultural plastics, has been measured using dynamic oscillatory shear testing to understand molecular-level changes to shear and elastic behavior. Each sample was also characterized to determine thermal properties (DSC and TGA), and flow properties using ASTM D1238 MFI and capillary extrusion to determine shear viscosity vs shear rate. The combination of detailed molecular and thermal characterization, coupled with shear viscosity data for virgin and PCR samples should help delineate the characteristics required to produce a high quality ISBM bottle, and provide information for including PCR material in inkjet products to improve sustainability and meet recycling goals.

Injection stretch blow molding plastic bottles: Virgin vs. PCR - MFI isn’t the whole story

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.