Diamond-like carbon films for PET bottles and medical applications

The unique properties of diamond like carbon (DLC) film, including its chemical inertness and impermeability, make it possible for new applications in food, beverage and medical market segments. Although these fields involve relatively higher risk for customers, the expected great advantages of DLC films have driven extensive efforts. In this paper, we present our recent results of development in high gas barrier polyethylene terephtalate (PET) bottles for beverage use. We also demonstrate that DLC or fluorinated DLC is a promising candidate coating material for orthopedics implants and blood contacting devices, such as artificial joints, cardiovascular interventional devices, artificial organs and pacemakers. A unique technique of plasma CVD method has been applied to deposit DLC films on the inside surface of PET bottles. The DLC-coated PET bottle exhibits extremely high gas barrier properties against oxygen, carbon dioxide and flavors compared to conventional bottles. For the practical use of PET bottles as a commodity, high speed and low cost coating are essential and lately our newly developed high speed coating machine has been successfully operated for the large production of hot tea drink bottles.