Characterization and production of agglomerated cork stoppers for spirits based on a factor analysis method

Abstract

The decision-making in the investment of a new line of stoppers based on agglomerated cork requires knowledge of the composition and its contribution to its performance. For this, it is necessary to observe the leading products on the market and to test a series of prototypes with different formulations. The development of manufacturing products made by cork, such as bottle stoppers, benefits strongly from accurate chemical and structural characterizations, correlated to the final material performance. A wise starting point to fulfill such requirement consist of comparing available products in the market to be compared with different prototypes with varying composition. This work presents a blind characterization of a series of cork samples through a non-supervised exploratory analysis designed to select agglomerated corks for spirits and still wines in the packaging industry. A total of 18 batches, with 3 of them being high-end commercial products, were used to build 15 different prototypes. They were subsequently characterized with the exact composition of microgranulated cork as the unknown variable. Statistical results based on 14 parameters related to the physic-thermo-mechanical properties indicate that the suitability of selecting the stopper relies on the study of only 4 or 5 of the initial parameters. Hence, it is shown that a reduced number of parameters may be considered to properly describe the mechanical behavior of agglomerated cork, allowing the wise choice of the most convenient material for the intended application. The factorial map reveals that the only sample batch manufactured based on the tested prototypes correlates with the three of the products supplied by the competence.