The capability will now provide food and beverage brand owners with a broader range of PET container aesthetics and performance capabilities than previously possible. For example, the process enables white or silvery coloured bottles to be made without additives which can limit package recycling.
Containers also have a unique surface feel and provide tactile ‘traction’, which minimises slipping. This process also blow-molds details more prominently, which enables decorations such as embossed logos to stand out better.
The Opti bottle technology provides desirable features for those brand owners looking for a distinctive, new, visual presence, while at the same time retaining the recycling benefits that inclusion in the clear PET waste stream offers.
“White Opti bottles provide an environmentally friendly option to conventional bottles which use additives to achieve a similar tint,” said Frank Semersky, vice president, PTI. “Instead of being a contaminant to the clear recycling stream, white-foamed bottles will mold into a transparent bottle after remelting and subsequent processing.”
In addition to white or silver, blue and green hues can also be used, since those colour streams already exist in traditional PET recycling. The technology also is capable of producing bottles in a variety of pastel colours. However, these cannot be recycled as part of the clear PET stream. Containers can be made from slightly translucent to opaque depending on the desired aesthetics and performance characteristics.
Because the foam process adds stiffness, lightweighting of up to 5% is also feasible without significant loss of performance. Furthermore, the technology can produce bottles with significant light barrier characteristics –up to 95% reduction in transmitted light.
PTI’s Opti bottle capability is based on using the MuCell micro-cellular foam injection molding technology to mold preforms, which then can be blow-molded on conventional equipment. The bottles are made in four basic steps:
“Initial evidence is that at higher gas levels, foam containers can withstand hot filling without excessive shrinkage,” said Semersky. “This means that hot-fill applications are within the realm of possibility. We also can run foam bottles with a variety of barrier additives to meet shelf-life concerns.”
In addition to PET, the foam bottle technology is applicable to other resins such as polylactic acid (PLA) and polyethylene naphthalate (PEN).
Source: Plastic Technologies Inc
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