Large stackable PET containers

CYPET: New stackable PET packaging solutions, as a replacement for HDPE jerry-cans

2021-02-15 5:33 min Blow Moulding & Coating, Bottle development and design

BACKGROUND

HDPE jerry-cans are used for the storage and transport of liquids for a very wide variety of applications, like foodstuffs, pharmaceuticals, chemicals, fuels, lubricants, etc.

Jerry can sizes vary from 4 to 35 liters. For edible oil, 15 to 25 liter sizes are preferred for export, hotel, restaurant and catering. The handle is one of the main advantages why end-users prefer buying products filled in jerry-cans rather than other packaging. Drawbacks of the HDPE jerry cans are the relatively heavy weight, lack of transparency and inaccurate neck dimensions.

There is a trend for HDPE jerry cans to be replaced by PET stackable bottles due to the substantially lower weight. With careful design, the weight of a PET stackable bottle could 40% less than the equivalent size HDPE jerry can. Additionally, PET exhibits high mechanical strength, transparency, a smooth and glossy surface finish and can be 100% recycled back to food-grade PET. Importantly, the neck of a PET container is injection moulded, with very accurate dimensions, enabling leak-proof closure without the need of costly wads.

The main drawback of PET has been the inability to have an integrated handle, like for HDPE jerry cans. This had been resolved by inserting a separately moulded handle in the neck of the PET bottle, which involves making or buying the handle and assembling it onto the neck of the bottle. This extra cost for the handle reduces the overall cost saving that arises from the lower weight of PET stackable bottles.

TECHNOLOGY

PET stackable bottles can be produced using either single-stage or two-stage PET technology, with single-stage being the most suitable method considering:

1. The usual advantages of single stage vs two-stage technology:

Substantially lower energy consumption.
Lower blowing pressure.
No packing materials for preforms.
No storage space or transport for preforms.
Less labour requirements.

2. The quantities of stackable bottles required are usually within the capabilities of single-stage technology.

3. Limited preforms supply for two-stage bottle blowing for this application.

4. Ability to optimize bottle weight, offered by the single-stage process, rather than having to use the weight of preforms available in the market.

CYPET Technologies Ltd offers its patented single-stage PET processing technology, which enables the production of large PET stackable bottles with integrated rigid handle up to 50 liters. No other single or two stage machine can produce larger than 25-liter PET stackable bottles.

In 2015 CYPET had successfully executed its first project for replacing HDPE jerry-cans with PET stackable bottles for edible oil application. The bottle design was developed by CYPET engineers to reduce weight for maximum strength, saving up to 50% raw material cost compared with HDPE jerry cans. Since the

successful completion of this first project, CYPET has received orders for 4 additional systems to produce PET stackable bottles of 9, 16, 17, 18, 20 and 25 litre sizes.

CYPET’s unique single-stage technology offers two significant advantages compared to other single-stage machines:

1. For easy and comfortable handling of stackable bottles, CYPET machines can produce bottles with an innovative strong integrated handle, which eliminates the need for additional and costly production steps of producing a handle separately and then fitting it on the bottles. Additionally, the handle being of the same material as the bottle, makes the bottle easily recyclable.

Photo credit: CYPET Technologies

2. CYPET offers the only single stage system available globally, capable of producing up to 25 litre stackable bottles with 4 cavities. This offers almost double the productivity compared with the next biggest system available, which produces with only 2 cavities.

STACKABILITY

HDPE jerry cans and PET stackable bottles can be stacked on each other, without requiring carton or plastic sheets between each layer of bottles. Depending on the application and the logistics in different countries, there are varying requirements on how high the bottles need to be stacked. It is important to define correctly the stackability requirements for each case, especially distinguishing between:

1. Static conditions: How many bottles high can be stacked in a warehouse.

2. Dynamic conditions: How many bottles high can be stacked in a truck or container during transport.

The importance of supporting the stacked bottles from all sides must be understood, especially for dynamic applications where harsh driving conditions (poor roads, sudden turns) may result in the toppling of the stacked bottles.

PET-IN-BOX SOLUTION

An alternative stackable packing solution is the container-in-Box concept, where a light-weight plastic container is placed inside a carton box. In this case the stacking forces are taken by the carton box, so that the plastic container can be very light in weight. The carton box has an opening at the top, exposing the neck and the handle of the container, so that the package can be carried and emptied without the need to open the carton.

This solution has been used for edible oil using HDPE light-weight containers, but now for the first time globally, CYPET has implemented a project with a PET container with integrated handle as a PET-in-Box solution. This innovative PET packaging offers an economical alternative to the HDPE equivalent and has the same feature of the neck being off-center to one side, to facilitate pouring of the contents.

As with the stackable bottles solution, the PET-in-Box is offered by CYPET with an integrated handle and also with the capability of 4-cavity production, the most productive single-stage system available for these sizes of PET containers, as can be seen on this video.

Photo credit: CYPET Technologies

The neck of the PET container is slightly slanted, making pouring of the contents even easier, however any automatic capping equipment needs to be able to cope with slanted necks. Additionally, the base of the PET container includes a step, providing a grip for facilitating tilting the container for pouring its contents.

This convenient and ergonomic packing solution can be evaluated as an alternative to the PET stackable bottles solution, comparing the extra cost of the carton to the saving from the lower weight of the PET container. A cost-performance balance must be found, depending also on the stackability requirements. The PET-in-box solution can exhibit better stackability performance, when a strong carton is used, so it can offer a better solution for more severe stackability requirements.

LATEST DEVELOPMENT – HORIZONTAL NECK

Having an off-center neck to facilitate pouring of the contents for the PET-in-Box solution, resulted in a slanted neck, which may cause inconvenience for automatic capping equipment that has been used for horizontal neck containers. This resulted in an effort by CYPET to design a PET container and a production process that would enable production of a PET-in-Box solution with a horizontal neck, to eliminate the capping issues with slanted necks.

CYPET’s design team has successfully designed a container, as well as an upgrade to the CYPET machine, which achieves the PET-in-Box packaging with a horizontal neck, keeping all its other advantages. This makes the PET-in-Box solution an even stronger candidate for replacing HDPE, as the same filling line can be used interchangeably for the bottling of the contents.

The images below illustrate this new development, which is now on offer by CYPET with systems for 2 as well as 4 cavity production, depending on the quantities required. This production capability includes the integrated handles, which are moulded into the preforms during the preform moulding phase of the process.

Photo credit: CYPET Technologies

ALTERNATIVE PET-IN-BOX SOLUTION

The newest container manufactured on a CYPET machine for stackable edible oil packaging, is a 17 L wide mouth container, with a 110 mm neck diameter and an integrated handle, which is placed in a carton box, rendering the complete package stackable, with good stacking stability.

Photo credit: CYPET Technologies

This 110 mm neck jar with integrated handle, replaced a 63 mm neck bottle of the same size, which had a separately moulded and assembled handle. The CYPET solution has a weight of 235 grams including the handle and the bigger neck, compared with the previous container weight of 250 grams without handle, or 265 grams with the separately moulded handle. As a result, the CYPET solution provides the following benefits:

1. A saving of 11.3 % in weight and raw material cost.

2. Saving of the cost of assembling the handle on the container.

3. A superior clarity container compared to the previous container made with the 2-stage process.

4. A stronger container compared to the previous container made with the 2-stage process.

5. A container which is easier to recycle, as the handle is made from the same material.

6. A container with much less environmental footprint, considering the elimination of the need to:

Transport preforms to the factory (saving fuel).
Store preforms (saving space).
Heat preforms for blowing (saving electricity).
Higher blowing pressure (can blow at lower pressure, saving electricity)

CONCLUSION

With the commercial availability of PET processing machines by CYPET Technologies, capable of producing PET stackable containers, there is an opportunity for substantial savings in raw materials by shifting from HDPE jerry cans to PET stackable bottles or jars with ready integrated handles, considering the following benefits: