Transparent Barrier Coatings Update: Flexible Substrates

Abstract

SiO_x thin films continue to be developed for polymeric flexible substrates. During the past year significant progress has been made on plasma deposition onto PET, LDPE, BOPP and BON polymer films. In addition, the first two 1.5 meter wide plasma roll coaters were completed and installed. The current state of the roll-to-roll coating developments on BOPP, LDPE, PET and BON will be reported for the 0.3 meter wide roll coater, R9, the 0.66 meter wide roll coater, Flex-1, along with data from the 1.5 meter wide coater, Flex-3, oper ations. The article focuses on a new stretch tester that measures oxygen trans mission of stretched SiO_x coated polymers. Data from the plasma coatings along with comparative measurements made on commercially available evapo rated products clearly shows a strong inverse relationship between the SiO_x coating thickness and the onset of failure (strain) S_f. Plasma coatings were stretched to 11.9% before failure occurred while the evaporated materials degraded at S_f = 2-3%. The stretch tester is a repeatable technique to assess the convertibility of the SiO_x coated polymers and to make quantitative assess ments between competitive materials. A model is also presented outlining the key parameters in achieving gas barrier properties with thin SiO_x and AlO_x coatings.