PETpla.net Insider 07+08 / 2011

BOTTLE MAKING 19 PET planet insider Vol. 12 centre of the lower antenna is used to distribute the gas inside the bottle. In order to enhance the ion bom- bardment on the interior bottle wall during the deposition process, a nega- tive bias is applied on the bottle by means of a metallic bottle cage. There are various methods to extract the ions from plasma and to enhance the bombardment onto the substrate. DC bias for example can only be used for conductive substrates or films, and is therefore not suitable for polymer sub- strates. Since a charge accu- mulation does not occur for RF substrate bias, it is applicable to PET bottles. Substrate bias- ing can be used with the new reactor by electrically isolating the substrate holder from the chamber walls and placing a radiofrequency (RF) biased electrode (bottle cage) on it. This additional plasma source (RF source, Advanced Energy, Filderstadt, Germany) can be ignited independently from the MW source allowing three dif- ferent operation modes: MW-, RF-, and dual mode. Developing a new coating process, the aim of this project was to study the effect of the substrate bias on the coating performance. A process that was developed in earlier stud- ies was chosen. Hydrocarbon films (a-C:H) were deposited using acetylene (C 2 H 2 ) as layer forming precursor and a two staged pulsed plasma process with a fixed set of process parameters, which are shown in Table 1: Parameter Value Microwave frequency 2.45GHz Microwave power input: 1500W RF frequency 13.56MHz Pressure 20Pa ton (MW pulse duration) 5ms toff (MW inter- pulse period) 25ms Table 1: Fixed set of process parameters used for deposition of a-C:H films on PET bottles Are your standard PET preform molds making you as much money as they should? Ask how MPET with iFlow technology improves production and achieves greater quality results. Innovation doesn’t happen in isolation. It happens when blue-sky thinking meets down to earth know- how and exceptional supply chain execution. The sort of innovation that Mold-Masters is known for, now applied to PET tooling for industry-leading results. Introducing MPET – the new PET preform tooling solution designed for the standards of tomorrow. Mold-Mastersand theMold-Masters logo are trademarksofMold-Masters (2007) Limited. © 2011Mold-Masters (2007) Limited.All rights reserved. Think about it. moldmasters.com/thinkaboutit [email protected] The deposition process consists of a pre-treatment of the polymer in an oxygen plasma and the final deposition of the barrier layer. The corresponding set of process parameters is shown in Table 2: Stage Parameter Value Pre-treatment Oxygen flow rate 60sccm Treatment time 0.5s Barrier layer C 2 H 2 flow rate 40sccm Argon flow rate 400sccm RF bias 0 – 80V (20V steps) Coating time 5s Table 2: Set of process parameters used for deposition of a-C:H films on PET bottles sensitive BEVERAGES