Manufacturers across the divide continue to produce quality products. We are all too familiar, with the attractive transparent packaging of toys, imported fruits, clothes, pens amongst other things. Unlike the previous times, customers can still have a glimpse into their prospective purchases, carefully examining them without necessarily compromising their state or quality (food).
It is as a result of these demands that the shrink film was developed. In the formative years; we were all accustomed to the brown paper bags which had our tree population on the decline. Subsequent move to the opaque store-name-christened polythene was a further disservice. Then came the perfect solution to all these problems, the shrink film.Initially, the shrink film was exclusively made from PVC (Polyvinylchloride).This is a plastic polymer (third most used plastic in the world) that had the capability of sealing products with a thin layer of plastic sheet. These sheets were often transparent to allow the customer have a view of the product.
The sheet would be wrapped over the product and passed over a heat tunnel or a heat gun. Normally, the length or circumference of the product would be measured, 10% of this value would be added then the sum is divided by two, this would give the size of PVC shrink wrapping to be used. PVC has the ability to shrink by 40% percent giving the packaging a tight grip of the product.
However, with time it was noticed that PVC could release small amounts of hydrogen chloride giving the products a characteristic smell in addition to poisoning. The sealers also would have small carbon deposits. The presence of a plasticizer in PVC had the drawback of hardening and shrinkage during cold weather and extreme stetching with subsequent temperature increases.
These drawbacks meant a suitable shrink film devoid of a plasticizer be developed. Polyolefin was found to have the packaging abilities of PVC but lacked the setbacks that faced the latter. It became a preferred choice of packaging. Offering a stronger seal and fewer odours. Its lack of plasticizer meant no physical changes to the shrink film. It would become the perfect storage solution; all weather .Lack of chlorine in its polymer meant no hydrogen chloride previously characteristic of PVC.
However, while its predecessor PVC enjoys machine compatibility and low cost purchases, polyolefin is the opposite, it remains relatively expensive and hard to use alongside machines.PVC on the other hand remains a suitable choice for manufacturers who don’t deal with edible products. Owing to its cheap price and machine compatibility it is a manufacturers darling.
It is of note that, both polymers are ideal for different packaging purposes. The choice of shrink film is determined by the product, budget and level of technology the producer in question has.
The undeniable fact is, packaging being the cornerstone of branding and advertising can be responsible for high sales volume or the reverse. Manufacturers and producers alike are today faced with the tough task of choosing the ideal packaging material. In the end the functionality of the shrink wrap can only be determined by the manufactures and producers.