Form meets function

THE FIRST plastic bottles for ketchup appeared some 30 years ago, as multilayer extrusion-blow moulded PP with an EVOH film to help prevent food from deteriorating as a result of contact with oxygen. After that, PET multilayer bottles made their debut.  Then HDPE, with its design versatility, and cost-efficient and environmentally friendly features, took hold of the market.

But for all the changes that ketchup bottles have already gone through, it appears there is still room for improvement. SIPA, whose expertise lies in plastic container manufacturing and filling, can clearly say that the transformation of the ketchup bottle is not over. Adding yet another packaging breakthrough to the list, the company developed a hot-fillable PET ketchup bottle. And this design, created in 2013 at the prodding of SIPA’s converter customers, is challenging the cost efficiency of aseptic filling and the looks of HDPE designs.

Alternative to aseptic filling

SIPA believes the new design is a highly cost-competitive alternative to aseptic filling because the  aseptic process requires very strict CIP procedures. The line has to be made in such a way that it has no dead spots where bacteria can grow, and be made of polished stainless steel like AISI 316 for a smooth surface. These are precautions that very much increase the cost of the plant and its maintenance in comparison to an almost standard process as hot fill.

The usual problem with hot-filling plastic bottles (particularly those with long necks sometimes used for ketchup), however, is that when the contents cool, their volume reduces and creates a partial vacuum. The bottle walls collapse and the label becomes partly or completely unstuck. Judging by how bottles were made then, it can be said that ketchup makers solved the problem by designing bottles with panels that withstand the distorting effects caused by the changes in internal pressure. This type of design is very functional, but falls short on aesthetics.

Overcoming challenges in hot-filling bottles

Numerous computer simulation tests offered SIPA experts more accurate predictions of how different bottle designs are likely to behave after these have been hot-filled. After several tests, it became clear that something radical needed to be done with the shape of the bottle to stop this vacuum effect from ruining the package.

Designers took an existing ketchup bottle design, shortened the neck and softened the angles around the bottle body to prevent the collapsing and to provide an attractive appearance. The result is a bottle that can be filled between 85° and 90°C, stays in shape afterwards, and prevents “label crinkling”. It’s a bottle that has form as well as function. What’s more, it can be produced on SIPA’s SFR rotary stretch-blow moulding equipment equipped with an oven intended for heat-set and oval containers.

According to designers,  frequent squeezing does not necessarily cause the label to wrinkle, and there’s no need to use a special type of material or adhesive to go with the new bottle. The design of the bottle itself provides a good shape suitable for the label. The walls of the bottle permit the application of the label without the causing the formation of “holes” that can prevent the label from sticking.

Converters interested

The new PET bottle comes in 20 fl. oz. Several converters have already expressed their interest in switching from HDPE and from glass to the new PET design. One converter has in fact approved the design and has carried out its own filling tests with positive results.

Making thAir Jordan IV 4 Shoes