Pigmented aqueous barrier coatings

摘要

The desire for more sustainable packaging has led to the development of new packaging materials that are fiber based.Aqueous coatings are a pathway to improve the recyclability of these materials.Pigments used in these coatings can improve the performance of the coating and reduce cost while further improving the recyclabil-ity.Mineral pigments are also considered to be compost neutral.In this paper,we provide the reader a better fundamental understanding of the mechanisms by which pigments work in barrier coatings.A pigment's mineralogy and physical characteristics are important to how it will perform,and there have been recent pigment developments that improve coating performance.This paper shows that some pigments are better than others in particular barrier applications.Also,pigmented base or pre-coats can be used to prepare the surface for more highly functional coatings that go on top,improving the barrier function of packaging material and reducing overall cost.Finally,the converting operation is of major importance in driving formulation choices for barrier applications.Application: This paper offers a review of the pigments used in these barrier coatings.The review includes the mechanisms by which they work and recommendations for pigments that are best to use for various barrier applications.This paper also provides examples of how the various pigments may perform in a barrier application.