Everybody is well acquainted with large bottles with huge handles or grips. Few know that the general handle designs are incompatible with PET due to the difficulty of blow moulding around the grip. The handle or grip is often manufactured separately from a different material than PET often PP and later inserted into the bottle or container mould around which the PET bottle is blow moulded. This is a difficult process to execute, as one of the trickiest elements is to make sure that the grip is perfectly placed inside the mould. If that is not done correctly or if the material isn’t heated just right, you either won’t ‘capture’ the grip or you will puncture the material.
The process also requires the installation of a purpose-built, proprietary reheat/blow moulding machine.
At the end of 2008 Langer Juice Co. of Canada started to market its 3-L PET jugs with auto-attached PP handles, developed by Plastic Engineering Technologies in Canada.
At that moment it was unique, to create PET-bottles incorporating a polypropylene handle that was inserted into the mould, and the container stretch-blown around it.
The empty containers weighed 105 g, and the PP handles weighed 20 g. The new lighter-weight, recyclable packaging was designed to increase Langer’s offerings of lightweight, eco-friendly bottles.
That was for juices, no one had been able to successfully create a commercial, handled PET bottle for liquors due to the difficulty of blow-moulding around a grip. But a two-year development effort between McCormick and Amcor achieved success by ensuring an extruded solid polypropylene grip placed perfectly in a mould.
In March 2008 McCormick Distilling Co introduced its 1.75-litre bottle made by Amcor PET Packaging, the first commercial PET liquor bottle with built-in handle. Although large, handled PET bottles for juice appeared on the market several years before, choices for handled liquor bottles had been limited to glass or polyvinyl chloride.
Although technically feasible, this solution, due to its risky and relatively expensive manufacturing, didn’t satisfy. A breakthrough process to enhance the grip on large containers and allow easier handling of hard-to-grasp multi-serve packages was to be expected to emerge any day. And it did.
An industry collaboration between the European division of Plastic Technologies Inc. (PTI), French machine manufacturer Sidel, and consumer goods company Procter & Gamble (P&G) came up with the, what they called, Deep Grip.
Working with injection stretch blow moulding (ISBM) equipment, the new containers offer grip depth of more than 1 inch (2,54 cm) on each side with a web thickness of less that .01 inches (0,25mm). The Deep Grip technology provides flexibility on handle location, shape and diameter, and can be used on containers as large as 6 litres or 1.5 gallons, and with diameters of 220 mm or 8.6 inches.
Deep Grip creates a grip for the consumer that is deep enough for the average-sized hand to completely close around and still not have the fingers of the person holding the bottle touch the container wall. It allows consumers to pour liquids easily from multi-serve containers
The bottles and their built-in handles are made from the same raw material on Sidel equipment in a two-step process. The bottles are made via conventional stretch blow moulding, and then a built-in secondary process in the same machine forms the handle. The ISBM process creates a handle with the grip web located where the hole would be in traditional handled bottles.
The development is one of the first commercially-viable handle processes that harnesses the advantages of ISBM. Injection stretch blow moulding offers several benefits compared to the extrusion blow moulding process that is typically used to produce handled bottles. Compared to extrusion blow moulding, ISBM enables light-weighting, higher output per cavity, mechanical benefits (top/side load, drop and creep resistance) and smaller equipment footprint. The light-weighting (20-25%) is possible because, in addition to functionality, the grip geometry also provides structural benefits which enable a reduction in bottle gram weight.
The process is applicable to a broad range of ISBM bottle polymers including polyethylene terephalate (PET), high-density polyethylene (HDPE), bi-axially-oriented polypropylene (BOPP), polylactic acid (PLA) and others.
The initial target markets for the Deep Grip containers are detergent bottles, household cleaner containers, milk, edible oil and motor oil containers, baby bottles and containers for non-carbonated beverages such as juices, ready-to-drink teas and waters.