A question on inline coated PET

Question: The In-Line Coating of biaxially oriented polymers, especially BOPET and more and more upcoming BOPP is a fast growing technique due to the tension of economic production. In-Line Coating of PET is well known and done for years know, but does anyone know, how big the market of In-Line coated BOPET really is (percentage coated/uncoated BOPET)?

I am not sure if anyone knows what percentage of PET products are in line coated in the global market, perhaps within a company this is known or perhaps within a product category. One thing is certain though; it is likely more wide spread than many film users might know. I expect that many of the products which are specifically designed for particular applications might be in line coated. For instance metallized films with metal adhesion promoters are in line coated and many primed films are. When I was making PET films much of the photographic base films were “Sub” coated using in line coating. 

PET is a nice application for in line coating as the temperature of the stretched sheet permits the easy use of water as a solvent. Also, while there may be a preheating penalty for in line coating, the PET preheat temperatures will tend to be high enough that the water solvent can be evaporated without much of a preheat penalty. Preheating problems are always more acute on older lines with shorter preheat sections.

In my recent experience with current PET film manufacturers, the only possible down side I can see to the use of in line coating appears to be some resistance to the incorporation of coextrusion into the film production lines as the in line coating allows an alternative approaches to product production. Personally, I think the flexibility of coextrusion, coupled with in line coating, would allow a greater degree of freedom in new product development and imaginative new products as well as cost reductions.