Study of functional barrier layer on PVC by PECVD for migrations resistant

Abstract

Based on the perfect barrier properties of inorganic coatings, much of the thin-film encapsulation technology has been development in the food and pharmaceutical packaging industries using silicon nitride (SiNx), silicon oxide (SiOx), aluminum oxide (AlOx), and diamond like carbon (DLC) coatings for no-humid sealing. Here a new application of SiOx coatings in migration resistant property has been investigated. As known, di-(2-ethylhexyl) phthalate (DEHP) is one of the most frequently used plasticizers in polymeric films, especially in polyvinyl chloride (PVC) films. Though the plasticizer can well improve the film stability, fluidity and low volatility, DEHP is easy to migrate from PVC films into foods and food simulants when it contains them. It results in a risk of causing public health damage and food safety problem. Hence a barrier layer, SiOx coating, is employed to prevent the migration of DEHP. This paper is to explore a feasibility of SiOx barrier layer for protecting DEHP migration. The SiOx coatings were deposited by plasma enhanced chemical vapor deposition (PECVD) process for this proposal. By using HMDSO and O2 as precursors and oxidant for SiOx deposition, we obtain hybrid components of organic and inorganic coatings, which were mainly dominated by O2/HMDSO ratio, applied power and working pressure. Migration resistant property of SiOx coatings is then discussed as a function of chemical structure, surface topography, compressive stress, and their thickness in this work. © 2012 Elsevier B.V.