Case histories


GRAHAM PACKAGING opens a new chapter in PET food packaging

ThermaSet® PET containers from converting giant Graham Packaging could be the next big thing in food packaging. These hot-fillable, pasteurizable and retortable wide-mouth containers are set to provide serious competition to glass jars and possibly metal cans too. They provide cost advantages along the production chain, can be used as drop-in replacements on existing filling lines, and have increased shelf appeal for consumers. Graham Packaging is making them on SIPA single-stage injection-stretch-blow molding systems.

The new PET jars are just now beginning to appear on supermarket shelves after exhaustive testing and consumer acceptance trials. They are “the future of food packaging,” says Graham Packaging. Graham is currently producing 16-ounce and 24-ounce “blow and trim” ThermaSet® containers on a SIPA ECS FX system that was specially designed for the process. This system has an output of up to 11,000 units per hour. (Blow and trim is a process for making wide-mouth jars from standard preforms, by incorporating the thread into the blown part of the container and then laser-trimming and recycling the top to provide a perfect sealing surface.)

The ThermaSet® containers score big-time over glass jars when they hit the scales: the 24-oz jar for example (that’s around 730 mL for Europeans) weighs just 37 g, which is only a little more than one tenth the weight of a glass jar. Despite this, they are still very robust: they are capable of withstanding filling temperatures of over 96°C (205°F), and once filled and capped, they can be pasteurized for 5 to 10 minutes at over 96°C (205°F). The containers accept a variety of closures typically used for glass jars and metal cans.

The first jars hitting the market shelves, for example, have metal lug closures that are fitted on capping equipment normally used for glass jars. Graham Packaging chose SIPA because it wanted a high-output, highly capable single-stage injection-stretch-blow molding system. The ECS is capable of producing containers with the very high performance required for the filling process and for the remainder of the supply chain, all the way to the kitchen.

The ECS is the fastest single-stage system in the world. Some more advantages of the ThermaSet® jars are: trucks can carry close to 30% more units than glass versions before they reach their load limits; breakages are virtually eliminated along the production and transport chain, or if a jar falls off the shop shelf—with important savings in production downtime and clean-up; ThermaSet® jars are much more resistant to thermal shock caused by rapid cooling after hot filling, so lines can run faster and energy consumption can be reduced; noise on the filling line is notably lower than on lines filling glass jars; and because of the narrower wall thickness of the ThermaSet® jars, more can fit into the same display space. It goes without saying that the jars are fully recyclable.