Jay Yuan, May 2018
Bottle Internal Pressure Analysis and Test for Hot Fill (BIPATH) is a container, closure, and process design and optimization program for packages that experience pressure or vacuum during any part of the supply chain. It was originally developed for the hot fill PET bottle design at Stress Engineering Services, Inc. (SES) in 2006. Over the years, BIPATH has evolved and expanded to encompass a wide range of container types and pressure/vacuum-prone filling, processing and distribution systems. The container types include injection/extrusion blow-molded plastic bottles and cans, injection-molded or thermoformed tubs and cups, and aluminum and steel cans. The pressure/vacuum-prone filling, processing and distribution systems include hot fill, retort, high pressure process (HPP), carbonation, nitrogen dosing, steam flushing, altitude and temperature change in distribution, air-shipping, product out-gas or oxygen consumption, oxygen/CO2 ingress or egress and plastic creep deformation over time. BIPATH calculates the package pressure allowable, which is the pressure or vacuum that the package can sustain without any unacceptable deformations or distortions, and the package pressure residual, which is the pressure or vacuum generated inside the package. The ratio of the pressure allowable and pressure residual, known as package pressure safety factor, offers bottle suppliers and brand owners a simplistic way to measure how well (or bad) the package would perform at the early stage of the package and product development process since no physical bottle or finished good samples are required for the BIPATH program. The pressure or vacuum can be better managed and optimized using BIPATH through changes in container and closure design, product content, process conditions (pressure, temperature and duration profiles), and shelf life commitment. The validity and versatility of BIPATH program in managing the pressure or vacuum has been demonstrated in real world packaging and process design and optimization since 2006. The theoretical foundation of the program and a case study are presented in this paper.