Now the foam isn’t just on top of the beer, it’s all around it. Plastic Technologies, Inc. (PTI), Holland, Ohio, is making its novel oPTI lightweight foamed PET blow molding process available for beer bottles. The process can be used to produce monolayer PET foam bottles (gray bottle in picture) or a combination of a foamed layer and a standard solid PET layer. The blue bottle in the picture has a foamed layer inside and solid, pigmented layer outside. The brown bottle has a solid, amber PET layer inside and foamed layer outside. Dual layers allow customization of barrier properties: For example, oxygen barrier could be added to the inner layer and a carbon dioxide barrier to the outer layer. The foaming process reportedly allows up to 5% lightweighting without significant loss of performance, and it opens the door to new optical and tactile effects.
PTI’s oPTI process is based on preforms injection molded with the MuCell microcellular foam process from Trexel, Inc., Woburn, Mass. It involves injecting pressurized nitrogen gas into the injection barrel. The preforms reportedly can be blow molded on standard, unmodified stretch-blow machines. The oPTI process can also be used with PEN and PLA resins.