The technology is based on inserts made from the company’s Surlyn polymer, which is said to broaden the design scope because it is more flexible to the contrasting geometries involved in such thick-walled containers.
This is because the polymer allows for the individual moulding of internal and external walls, decoration techniques such as the casing of labels and inserts, the colouring of polymer inserts and the application of frosted and glossy effects
Process opens up new possibilities
"This multitude of design options made possible by this development is very exciting,“ said Prosper Zufferey, processing expert at Dupont Cosmetics Solutions.
As well as pointing out the fact that the use of the polymer allows for a wide range of finishes and colours, Zufferey also pointed out the fact that the process was more production efficient and eco-friendly.
"Because glass has been entirely eliminated from the bottle’s design, it is safer and more robust, easier and more cost-effective to produce, and, last but not least, easier to regrind."
The patented over-moulding process has been developed by DuPont’s affiliate in Japan, DuPont Mitsui Polychemicals, which is a joint-venture.
The process is said to be ideal for the production of thick-walled bottles and containers with a wall thickness of 10mm or more, and can also be adapted to have a high control of the neck diameter and its wall thickness.
The over-moulding is said to make a good alternative to standard finishings such as extrusion blow moulding or the over-moulding of glass inserts.
Working with a number of polymers
Zufferey also added that the company is working with using PET or PP as the material for the polymer insert, because of their resistance to chemicals in cosmetic lotions.
However, for more chemically agressive formulations, he said that the company is working towards the development of multilayer polymer inserts produced by extrusion blow moulding.