Aluminum oxide barrier coatings on polymer films for food packaging applications

Abstract

In the field of packaging, barrier layers are functional films, which can be applied to polymeric substrates with the objective of enhancing their end-use properties. For food packaging applications, the packaging material is required to preserve packaged food stuffs and protect them from a variety of environmental influences, particularly moisture and oxygen ingress and UV radiation. Aluminum metallized films are widely used for this purpose. More recently, transparent barrier coatings based on aluminum oxide or silicon oxide have been introduced in order to fulfill requirements such as product visibility, microwaveability or retortability. With the demand for transparent barrier films for low-cost packaging applications growing, the use of high-speed vacuum deposition techniques, such as roll-to-roll metallizers, has become a favorable and powerful tool. In this study, aluminum oxide barrier coatings have been deposited onto biaxially oriented polypropylene and polyethylene terephthalate film substrates via reactive evaporation using an industrial 'boattype' roll-to-roll metalliser. The coated films have been investigated and compared to uncoated films in terms of barrier properties, surface topography, roughness and surface 2 energy using scanning electron microscopy, atomic force microscopy and contact angle measurement. Coating to substrate adhesion and coating thickness have been examined via peel tests and transmission electron microscopy, respectively.

Development of an Oxygen Sensitive Model Gel System to Detect Defects in Metal Oxide Coated Multilayer Polymeric Films

“…This was evident from the unprocessed (control) pouches stored at 23 and 40 °C for the same duration as the processed samples (Figure ). These pre‐processing defects are also seen in other polymer substrates such as AlO x ‐coated, biaxially oriented PP (Struller et al., ). Other researchers have found similar results for metal oxide coating deposition through PVD or CVD techniques (Henry et al., ; Roberts et al., ; Yanaka et al., ).…”

“…Studies demonstrate that the gas barrier properties of metal oxide coated multilayer polymeric films decrease after sterilization, due to changes in their thermal and morphological characteristics (Dhawan et al, 2014;Zhang et al, 2017). Other studies have examined the barrier performance of metal oxide coating itself along with external factors that may lead to defects (Leterrier, Månson, & Wyser, 2001;Rochat, Leterrier, Fayet, & Månson, 2005;Singh et al, 2007;Struller et al, 2014). However, these studies have analyzed the performance of the coatings present on the exterior surface of films (Dhawan et al, 2014;Zhang et al, 2017), or of films that were not exposed to commercial sterilization conditions such as heating at 121°C under high moisture (Leterrier et al, 2001;Struller et al, 2014).…”

Biomimetic nanocoatings with exceptional mechanical, barrier, and flame-retardant properties from large-scale one-step coassembly

“…Similar barrier performance was achieved on PET, BOPP, HDPE, and LDPE films, as shown in Table 2. The results show that the PVA/MMT nanocoating is especially ideal for polyolefin (BOPP, HDPE, and LDPE) films, which inherently have excellent moisture barrier properties but are a very poor oxygen barrier ( 43 , 44 ). The PVA-based nanocoating perfectly supplements the need of polyolefin films to achieve an outstanding barrier to both oxygen and moisture.…”

Reduced Water Permeability of Biodegradable PCL Nanocomposite Coated Paperboard Packaging

“…The results show that the PCL coating has a decrease in permeability (15 %). The sample with PCL-Al 2 O 3 (K/P/1Al) coating also has a similar (14 %) decrease in water vapor transmission and does not show a higher decrease in permeability, even though Al 2 O 3 is known for its ability to improve barrier performance of polymers 18 . PCL coating with SiO 2 nanoparticles (K/P/2Si) shows a better improvement in permeability (decrease by 19 %) after 48 h WVTR test.…”