Characteristics and Mechanism of Bubble Formation in Plastic Packaging for Food

Abstract

Heat-sealing technology, which is used for plastic packaging, entails laminating multiple kinds of films together to form a barrier with varying permeability and stiffness. Creating a heat seal consists of heating the heat-seal material and then immediately cooling it down. However, overheating the heat-seal material can introduce defects such as bubble formation. This study examined the effect of the moisture content on bubble formation by using retort pouches as the sample material. The material is composed of polyester, nylon, and polypropylene as the outermost layer, barrier layer, and heat seal material, respectively. A mechanism of bubble formation is proposed on the basis of the moisture adsorption characteristics, viscous elasticity, and barrier characteristics of the sample material.