The growth of the 5-gallon bottle

The standard bottle used in water coolers/dispensers is the 5 US gallon bottle (18.9 Litres) which is now becoming more and more common in European factories and offices. PET has already made some inroads into this market. The Italian companies PDC and Siapi intend to ensure that the trend continues.

The 5-gallon water bottle is already common all across the USA in offices and factories. It is becoming increasingly common in Europe, and in areas such as Latin America, where tap water is undrinkable or non-existent, the 5-gallon bottle has found a market in domestic use. The overall market for 5-gallon bottles is growing at double figure rates. In Italy, for instance, the number of water coolers installed in 2000 was 90,000 compared with only 50,000 in 1999. The potential for a 3-gallon domestic cooler is now being seriously examined, with the major water companies delivering direct to homes, bypassing supermarket distribution. The market is only waiting for one of the major domestic electrical equipment suppliers to take the first step.

The material used today for the 5-gallon bottle is overwhelmingly polycarbonate (PC). The material is, however, costly - much more so than PET, and hence only refillable bottles are produced. This also applies to PET bottles, which are currently produced principally on single stage machines outputting typically 100 bottles per hour. For the market to evolve at the desired rate for PET higher outputs will certainly be required.

New project

Last year the Italian company PDC, working for Drink Cup, the biggest Italian bottler and distributor of water for coolers, initiated a project to develop a new 5-gallon bottle. PDC, part of the Multipack Group and a specialist packaging design and development company, selected PET because of several advantages it has over PC. Cost was the major factor, but also the superior neck finish available to give improved sealing, and the absence of any plastic residue inside the bottle. A further important consideration was the fact that PET would ultimately allow for the production of a non-returnable bottle. This would considerably simplify Drink Cup’s distribution logistics, even if the bottles had to be collected for recycling. Single trip bottles would mean that the containers could be produced in-line at the bottling plant and would eliminate the need for bottle washing and disinfecting equipment, which is calculated to be the highest cost of the filling line!

Higher output

The high production volumes at Drink Cup were considered to be incompatible with the single-stage machines available for 5-gallon bottles, and so a two-stage process was selected by PDC.

Production of the preforms was started by PDC at another Multipack company, Impet, who developed a special injection moulding press, mould tool and robot in collaboration with Husky.

The preforms they developed go from 700 grams for a refillable bottle down to 400 grams for a single trip bottle, which can be recycled at Impet.

The next stage was to find a suitable manufacturer of two-stage SBM machines to work on the project. The chosen company was Siapi, a manufacturer of single stage machines with plenty of experience in customised projects and in blowing high capacity bottles.

Starting in the early part of 2000 Siapi designed a new single cavity SBM machine, the EA 10-450/1, which is capable of turning out between 250 and 350 bottles per hour, depending on the preform weight. Format changes between 10 and 20 litres take about 45 minutes. The first 5-gallon bottles were blown at the Siapi factory in October 2000, and in the spring of 2001 full production commenced at the Drink Cup plant with two Siapi machines in line with the filling equipment.

The success of the project was acknowledged when the project (PDC), the preform (IMPET) and the bottle (Drink Cup) was awarded a “Packaging Oscar” this year by the Italian Institute of Packaging. Whilst previous PET bottles mimicked the shape of the existing PC bottles PET is a different material and much can be done to exploit its properties. It may very well be possible to further reduce the bottle weight, even where a refillable bottle is used. The story of the 5-gallon PET bottle has only just started. There are surely further technological and design innovations to come.

There will be a Siapi EA 10-450/1 operating on the stand at the K-2001 in Düsseldorf.