Content area
Full Text
PEER-REVIEWED TECHNICAL PAPERS: Following are expanded summaries of complete papers that are available on the TAPPI web site at www.TAPPI.org. On the page, click "the PLACE" in the section designated Journals.
Application: Understanding the mechanism of perforation in flexible laminates allows prevention of damage by penetration that can cause possible loss of barrier properties, package integrity, and product quality.
Puncture resistance is an important property in flexible packaging materials. In many applications, the packaging laminate is subject to damage by penetration. To control and optimize this property, understanding the mechanism of perforation in flexible laminates is important. Defining relevant methods for experimentally assessing the puncture resistance is also necessary.
Description of perforation failure of single-material films is relatively straight forward using basic material behavior such as "brittle" or "ductile." The situation for laminates composed of different types of materials is more complex. Puncture resistance of a multilayer laminate cannot be directly calculated from the properties of the constituents by a rule of mixtures or similar approach. Although different methods are available for describing the puncture failure of various types of systems such as thick laminates or reinforced composite structures, these methods have limited use for flexible packaging materials. In addition, subtle effects such as an influence of testing direction in the case of asymmetrical laminates often occur
Several methods are available in the literature for experimental evaluation of puncture resistance. Numerous laboratories have also developed in-house methods to address specific needs. The methods differ significantly with respect to testing rate and probe geometry and do not necessarily give the same results. Another issue concerns what type of test result-deformation, force, or energy-should evaluate material performance.
In this work, the authors develop a...