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Classic case studies in packaging

How the multilayered laminated collapsible tube was invented

Posted on Thursday, 07 December 2017. Posted in Flexible Packaging, Packaging Production . Written by S Chidambar

How the multilayered laminated  collapsible tube was invented CREST went on to become the highest selling toothpaste in the USA

We are now accustomed to seeing products like toothpastes, dentrifices and cosmetics in multilayered laminated tubes and hence we take this system for granted. There is, however, an interesting story on how and why this tube was invented and developed to its present state-of-the-art level. Harvard Business School has a well-known dictum – ‘In every problem, look for the opportunity.’ The multilayered laminate tube is a perfect example of this theory.

It all started in the late 1950s, when Procter and Gamble (P&G) developed a revolutionary new formulation for toothpaste that was highly effective in combating tooth decay (this was the first ever ‘fluoride’ toothpaste). Extensive research carried out earlier had shown that many Americans suffered from tooth decay but this research discovered that the incidence of decay was very low in regions where the local drinking water contained high levels of fluorides. Therefore, scientists worked on developing toothpaste formulations containing fluorides. The first such formulation that worked was developed by the University of Indiana, who licensed it to P&G who, as part of the deal, set up and built a high-quality research laboratory for them (which went on to become known as ‘The House That Crest Built’).

The fluoride formulation contained stannous fluoride as an active ingredient. The problem was that stannous fluoride (which P & G called fluoristan) was such an aggressive and corrosive chemical that it reacted with all metals and caused them to be affected on direct contact. This posed a major problem since, at that point of time, the standard toothpaste package was the collapsible aluminum tube that was produced by impact extrusion from aluminum slugs. (Collapsibility was essential as air or moisture could not be allowed to enter the tube after the toothpaste was dispensed).

Even when the tube was coated on the inside with the most resistive lacquers known, the incidence of fluoristan penetrating the lacquers and corroding the aluminum was relatively high and beyond commercially acceptable levels. However, the revolutionary new fluoride formulation was too good to defer its immediate launch and P&G gritted its teeth and decided to live with the problem until a suitable alternative package could be developed.

So, Fluoristan Toothpaste was launched in conventional aluminum tubes with internal lacquers and, needless to say, it immediately went on to become a monumental success. The American Dental Association formally endorsed the product as genuinely effective in fighting tooth decay, the first time it had done so for any product. P&G rechristened the product as CREST and it went on to become the highest selling toothpaste in the USA. However, the crying need for a suitable alternative tube system only assumed higher urgency.

P&G decided to entrust this project to American Can, who were also their largest suppliers of conventional aluminum tubes. In the late 1960s, American Can started working on replacing the aluminum body of the tube with alternative structures. What was important was that the structure needed to deliver a totally collapsible tube and, at the same time, provide a high level of moisture, gas and flavor barriers to preserve the toothpaste for the required shelf-life. And, of course, it had to be perfectly compatible for extended direct contact with the ingredients of the toothpaste.

American Can quickly realized that the material most suitable for direct contact with the toothpaste would be a continuous layer of polymer that would be impervious to the transmission of stannous fluoride through its surface. Although seamless polyethylene tubes were available, they were neither collapsible nor did they provide the requisite barrier.

American finally homed in on a multi-layered laminate construction for the tube body that comprised of multiple layers (5 to 7 or more) that included aluminum foils (for the necessary barrier and to provide dead-fold for collapsibility), paper (for non-creasing and to provide a flat surface for high-quality print graphics) and different grades of polyethylene films (to provide sealability, as adhesive layers for extrusion lamination and as the innermost contact layer for compatibility with the toothpaste). The laminate was first produced as a conventional flat laminate and then printed and converted into a tube by folding around a circular mandrel with the overlap seam heat-sealed using a lap seal. This tube body was then sealed to a molded HDPE top/ dispenser to form the equivalent of the conventional collapsible metal tube. HDPE was selected as the toothpaste also contained surface active ingredients that caused environmental stress cracking in LDPE closures on extended contact.

The bonus was that this new tube could be easily filled on conventional tube-filling lines and the heat-sealing required to close the tube after filling provided a totally leak-proof and hermetic seal that the conventional metal tube could not deliver (metal tubes were closed merely by folding over the ends and crimping the fold). Since the print decoration was done by flexography on a flat laminate surface, the graphic design could incorporate tonal effects and the the reproduction was distinctly superior to that obtained on conventional metal tubes, which could only be surface printed by letterpress after the tube had been constructed. The printing on the laminate was also scuff-resistant and aesthetics did not get affected by creasing and crumpling during handling of the tubes in the course of filling-sealing, distribution, or consumer usage, as was the case with metal tubes.

P&G thus ended up with a superior alternative tube system albeit a more expensive one at that point of time. Although American Can were the only source of this new tube for a very long time, CREST was introduced in this new tube in the early 1970’s with tremendous success and market growth world-wide. CREST was later recognized by the American Chemical Association as one of the 100 greatest inventions of all time for its formulation but also due in no small part to its revolutionary new packaging system.

Needless to say, the multi-layered laminate tube rapidly became the universal standard high-barrier packaging system for dentrifices and its usage has extended from toothpastes to other pasty and gel formulations in the cosmetics, pharmaceutical and food industries.

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