Colourants enhance consumer appeal

Edited by the Engineeringtalk editorial team May 23, 2003

Milliken Chemical reckons it has changed the beverage industry's attitude towards bottle caps.

Milliken Chemical reckons it has changed the beverage industry's attitude towards bottle caps.

Traditionally viewed as a commodity element, Milliken, through its ClearTint colourants technology, is showing how beverage caps can become an intrinsic and valuable part of packaging aesthetics by replicating beverage colour or brand colour in transparent polypropylene (PP) to enhance consumer appeal and brand image.

A reality currently in the process of being commercialised by three major drinks producers.

The concept of transparent, coloured PP closures is not in itself new.

Milliken has pioneered this development in a number of areas such as that of personal care products for which clarified coloured PP gives the highly attractive appearance associated with more expensive materials, while at the same time delivering simplified processing as well as the cost savings achievable with PP.

Commercialisation of applications in this sector led Milliken to review other possibilities to exploit the advantages of its ClearTint solid concentrate masterbatch in conjunction with other PP closures and the beverage market provided a natural outlet.

The highly competitive soft drinks industry thrives on product differentiation, not just in beverage formulation but also in packaging innovation.

In recent years the market has seen a number of packaging advances but these have largely been functional such as tamper proofing and gas barrier improvement.

However, the unique technology of ClearTint colourants offers the possibility of a real 'next step' in packaging aesthetics and on-shelf product appearance through transparent screw caps that provide a quality complement to the total package.

To aid this next step Milliken initiated a series of cap moulding trials, both injection and compression, utilising ClearTint in conjunction with a range of PP grades, impact copolymer, homopolymer and random copolymers.

These tests showed that the addition of ClearTint results in attractive 'translucent' closures with colours that tend to be brighter than can be achieved with traditional colourant technologies.

However, the real step-improvement in cap aesthetics comes with the addition of ClearTint to clarified PP and particularly to clarified random copolymer grades in which the combination generates excellent transparent colour that can be matched with virtually any requirement.

Although these trials are ongoing, the results to date have shown that the material is within the performance protocol common to major global producers in the soft drinks market.

Significant is that this aesthetic enhancement has been achieved without retooling and with only minor processing modifications.

Importantly, adding ClearTint to caps moulded in clarified PP not only creates a unique appearance which is unrivalled by pigment technologies, it improves productivity by eliminating the risk of shrinkage associated with them.

With different pigments PP freezes at different temperatures but different ClearTint colours have no influence on freeze temperature.

Whatever the colour, ClearTint crystallises at exactly the same temperature ensuring improved, consistent processing across the colour range.

Moreover, unlike pigments, ClearTint offers total colour flexibility and a greatly simplified approval process for closure producers.

Because ClearTint is based on only five primary colours, once these are approved all subsequent colours and colour-matches created by Milliken Chemical automatically meet approval criteria.

This offers a substantial advantage over the complex process for pigments that requires approval for every new colour.

According to Milliken Chemical, European Marketing Manager, Michel-Georges Roussel: "The benefits ClearTint can bring in this sector have been recognised by the market and have drawn an extremely positive response.

It's also been recognised that to achieve the very best visual effects, ClearTint should be used in conjunction with clarified random copolymer PP and we have been working with customers using this combination to match the colours of their bottle caps with that of their beverage product.

This has already led to the startup of a number of projects, on a global scale, which are now moving to commercialisation".