Although naturally clear (transparent), PET can be given a wide range of colours and can be formed into a wide variety of shapes in sizes ranging from small bottles and jars to large kegs.
Petainer’s own product line extends from 200 ml bottles to 40 litre kegs – and development of larger containers is currently taking place.
Brand owners require packaging which ‘stands out’ on the retail shelf and this is often reflected in innovative shapes and designs. PET is ideally suited to moulding into complex shapes. It can also be embossed, textured, printed, sleeved and decorated in a variety of ways.
When used in its natural clear state it has a transparency to rival glass, giving brand owners the opportunity to display the product directly through the packaging.
One of the material’s greatest assets is its strength. Carbonated soft drinks can generate pressure inside the bottle of up to 6 bar but PET can withstand even this high pressure with very little deformation.
Petainer offers consultancy services which are based not just on a technical understanding of what can be achieved with PET packaging but also on our own international market research into consumer behaviour and attitudes to packaging.
We use our market knowledge to design containers that have real impact yet are cost-effective to manufacture based on our own daily production experience.
Food safety
PET is an inert material which is resistant to attack by micro-organisms and does not react with food and beverage products. Health and consumer protection agencies around the world have approved PET as safe for use with foods and beverages.
Sustainability
PET is recyclable and has many environmental benefits compared with other materials.
Thermal stability
Many food and beverage manufacturers use a ‘hot-filling’ process to package their products because the high temperatures kill micro-organisms. This requires containers to withstand these high temperatures during filling and handling.
Until recently, ‘vacuum panels’ had to be built into PET containers to prevent them collapsing as they cooled and this to some extent limited the design freedom enjoyed by PET container designers. Now the industry has developed ‘panel-less' technology which has opened up a new range of creative design options.
PET is also being developed to give stable container designs capable of operating at temperatures higher than the 85°C typical of a hot-filling environment, allowing PET containers to be used in pasteurising and retort processing.
At the same time, product manufacturers are developing new techniques for aseptic filling, where the product and the package are sterilised separately and then brought together in clean room conditions. Because the containers do not have to be heat-resistant there are more design and weight options.
Barrier technologies
PET has intrinsic protective capabilities adequate for most products. However, some foods and beverages need additional barriers to maintain carbonation levels and to protect against oxygen permeation that might have a negative impact on product shelf life.
PET containers are now available with both passive and active barriers to meet the needs of these products.
A passive barrier prevents oxygen from entering and CO2 from leaving through the walls of the container. An active system actually absorbs oxygen from the product or from any air that penetrates the container from the external atmosphere, usually with an ‘oxygen scavenger’ that binds to the oxygen molecules.
Barriers can either be applied as coatings or require ‘multilayer’ construction of the container, with one or more barrier layers being constructed between interior and exterior PET walls of the container. The middle layers may be either passive or active barrier materials or both.
The latest coating technology is based on plasma impulse chemical vapour deposition of materials such as silicon dioxide on the inside of containers.
Current research and development is focused on ‘monolayer barriers’ which can be incorporated uniformly within the container material itself.
While meeting the requirements for which they are developed, barrier materials do not detract from the properties of PET which make it so attractive as a packaging material – properties such as chemical inertness, clarity (transparency) and recyclability.
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