To evaluate the failure potential of insulated packaging to heat outside, a so-called evaluation boundary for insulating packages was proposed for designing and estimating insulating packages based on the heat transfer law between the environment and a packaged product through packaging. Three evaluation parameters were suggested for describing the failure mechanism of insulating packages. The validity of the presented evaluation boundary was verified by the experimental data. Finally, a new design method of insulating packages based on the boundary was proposed and an application example was performed as a demonstration. The results indicated that the three evaluation parameters (which are thermal load, adsorption ability of phase change material (PCM) and system thermal resistance of insulating packages) are the key parameters for designing insulating package and that the performance of insulating packages is only determined by the thermal load. Moreover, the proposed evaluation boundary shows a good agreement with experimental results, and the availability of the new method to design insulating packages was affirmative through the application example
