Hans Werink
Project Manager Packaging

UHT milk in monolayer PET bottles

Many types of long-shelf life dairy products like UHT milk and flavoured milks need to be protected from light to keep their flavour and nutritional value. PET packaging looks and performs great and offers many marketing advantages in terms of design possibilities, user friendliness, mechanical strength, and cost. But in the past, its application in UHT milk products was not practical, because monolayer PET could not offer a sufficient light barrier. Holland Colours has introduced Holcomer UHT White, a highly opaque white colourant specifically designed for monolayer PET packaged UHT milk products. A number of leading dairy companies have recently introduced UHT milk and flavoured milk products in monolayer PET bottles containing Holcomer UHT, adding to the list of successful market introductions with this concept.

Milk, a steady performer with an image problem

Milk has been part of the human diet since time immemorial. Although the global milk consumption is steadily growing, local markets are under pressure because of changes in consumer trends. Competition is fierce so dairy producers have to find ways to make their product stand out against the competition. As a result the dairy industry is highly innovative, with new products being introduced all the time. Not only the dairy products themselves are under constant development, the packaging it comes in is also key to a successful market introduction. The use of PET enables creative designs that would be hard to accomplish with traditional carton packs and HDPE containers.

Consumption of ready-to-drink, long-life packaged milk has seen a healthy growth rate in the last decade. Within the overall market the share of Ultra High Temperature (UHT) milk has steadily increased to be almost a quarter of the total liquid dairy products consumed.

Of all liquid dairy products, the share of Ultra High Temperature milk (UHT), is steadily growing mostly in cartons and HDPE plastic packaging. Functionally, cartons and HDPE perform adequately, but if the challenge is to re-position milk then the possibilities with traditional packaging are fairly limited. The alternative is PET packaging.

Holcomer UHT - the white PET colourant for UHT milk

Until recently, monolayer PET packaging faced serious obstacles for widespread use with UHT milk, because the milk suffered in quality as a result of light penetration and no practical light barriers were available. Holland Colours has developed a special white colourant for use in monolayer PET for UHT milk packaging. With the introduction of this concept, the dairy industry can now utilize the premium appearance and the mechanical strength of PET, along with processing efficiency in preform and bottle production.

A breakthrough in light barrier technology

Consumers are sensitive to even slight changes in odour and taste. With UHT dairy products, extended shelf life is a key selling point, maintaining the integrity of the taste and odour of the product is therefore absolutely critical.

One of the key factors to assure that integrity is to create an effective light barrier. Light penetration causes the photo-oxidation of riboflavins like vitamin B2 and B12, and secondary auto-oxidation of lipids (milk fats) - which results in deterioration of flavour as well as degradation of the nutritional characteristics.

The harmful wavelengths are mostly between 380 nm and 550 nm and that is where optimum protection is offered. At dosing levels between eight and fourteen percent, depending on the wall thickness and the required opacity, Holcomer UHT is effective in blocking light at the levels required for this demanding application. Competitive white systems are predominantly resin-based compounds that have a fixed opacity at a given wall thickness and severely limit the possibilities for light weighting and package design optimisation.

Milk in monolayer PET - with uncompromised quality

Holcomer UHT white comes in a highly concentrated solid masterbatch format with a melting point of 255 °C. lt can be used with any PET resin on existing monolayer equipment without the need for additional investments for moulding, blowing or downstream equipment. Key benefits are:

Performance – Molding & Blowing

Injection moulding performance: unaffected cycle time
Blowing performance: equal line speed and no blow outs
Bottle integrity: no sidewall delamination upon bottle squeezing

Flexibility & Cost effectiveness

Competitive against current monolayer, multilayer and carton alternatives
Adjustable dosing level enables further light weighting of bottles without loss of opacity
Freedom in bottle design: light protection performance can be customized
Flexibility in sourcing of resin – no specific resin required
Moulded and blown on standard monolayer equipment – no additional investments required

In the marketplace

Design possibilities, premium appearance with high bottle surface gloss and endless choice in shapes
The consumer friendliness of PET: one-handed opening and closing, easy pouring, drinkable straight from the container
Product Quality: taste and nutritional value preservation equal to multilayer and carton packaging
Established technology: commercialised by leading dairy brands

Holcomer and UHT milk in PET – a proven solution

While there are other solutions available for opaque monolayer PET packaging, none of them have the flexibility, practicality and economy of Holcomer UHT, Holland Colours claims. With this concept, the light barrier level can be customized independent of design and bottle sidewall thickness - and the packaging delivers a winning combination - great appearance, great performance, and cost-effectiveness.

With the recent introduction by leading European brands of several UHT, ESL and flavoured milk drinks in opaque white PET containing Holcomer UHT White, Holland Colours has set a new standard in technology and in dairy marketing opportunities.

Hans Werink
Project Manager Packaging
Tel. +31 55 368 0700

Light protection for milk in PET