Slim blowmolded pack innovates way through postal regulations

A plastic package for sending mail-order vitamins and similar products through standard letter post, rather than the more expensive parcel post, has been introduced. The blowmolded HDPE package, with its width-to-depth ratio of more than 4:1, created a significant technical challenge for the processor, RPC Containers.

The package was developed by RPC Group's design office in conjunction with Pont Packaging, the company that markets and distributes the package in Europe. The Group's facility in Market Rasen, England handles the extrusion blowmolding of them. MPW highlighted Pont in an article in our May issue and mentioned this package in that article, but more details of its processing now have come to light.

On this package, the key requirement was that it must be less than 25 mm deep to fit the parameters of a standard letter size. At the same time, the neck opening needed to be as big as possible to ensure ease of filling. The dimension of the opening presented a significant technical challenge as the pack shape is outside conventional blow tolerances. "Ordinarily, the ratio of width-to-depth needs to be 2.5:1 to allow the shape to be blown with optimum material distribution, but that would not suit the letterbox size required by Pont," explains Jim Dale, RPC's design manager.

But trials eventually proved successful, and RPC Market Rasen—the Group's facility for handling projects involving unusual and bespoke plastic containers—took over processing and overall project management. The package's design elements include non-round trepanning of the neck to maximise the aperture, maintaining consistently flat side panels, and adding strength in the corners to allow quality wrap-around labelling.

The matching oblong cap is injection molded in polypropylene by RPC's facility in Halstead, also England. Once filled, the oblong bottleneck is induction sealed. Max van de Grift, supply chain director of Pont Europe, thinks his company has a winner. "The pack has already been shown at the Vitafood trade exhibition in Geneva to unanimous praise, and we are currently entering it into several packaging awards in the Benelux region," he stated. —Matt Defosse