In most cases, metal lids will be in contact with sensitive products, since they are mainly used to close those metal containers that are used to preserve vegetables, fruits, sauces, beverages, powdered formulations, and an endless number of foods. That is why these metal lids must arrive in optimal conditions of quality and hygiene to the filler who will be in charge of using them to close his canned product. The type of wrapping we use to pack the metal lids plays a very important role in this, from the moment they are manufactured by the canmaker to the moment they are used to close the can by the canning company. There are currently two main types of packaging used to keep metal lids in optimum condition: the paper bag (or paper sleeve) and micro-perforated heat shrink plastic. Which one is better? The answer is not so simple, so today we will analyze the main criteria to be taken into account when selecting the most suitable packaging.
Generally, lids inside paper bags are more comfortable to use by the filler, especially when the operator manually feeds the lids to the seamer. In most cases, the bag itself acts as an extension of the lid-feeding channel to the seamer, giving the machine some extra capacity.
This circumstance changes completely when the feeding of lids to the seamer is carried out automatically, that is to say, by means of unwrappers or debaggers in charge of removing the wrapping, either paper or plastic, that covers the lids. In this case, plastic-wrapped lids take advantage over paper because the automatic unwrapping operation is greatly simplified.
2. Moisture absorption:
There are several contaminating agents that threaten metallic lids, but perhaps one of the most important and harmful is humidity. In this aspect, paper bags, with a moisture absorption power far superior to that of plastic, ensure that the lids are kept free from possible oxidation due to the effect of water floating in the environment. This gives paper an advantage over plastic when exporting lids by sea.
However, it must be taken into account that the plastic used to package the lids is always micro-perforated, precisely in order to provide an escape route for the residual humidity in the lids. This makes the advantage of paper over plastic in this respect not so great. In addition, with a proper palletizing of the lids, we can ensure that the lids remain dry and free of oxidation.
3. Packaging automation:
When the need arises to automate the packaging of lids, plastic is always the best option. Plastic wrapping machines are always less expensive than their paper counterparts. In addition, paper bagging machines are more sophisticated machines that require more exhaustive maintenance.
The paper, being more porous, is more likely to host unwanted microorganisms that can lead to further contamination of the product. This makes plastic a more suitable material for handling in some occasions, such as inside a clean room (or filling room) where a high level of hygiene is required.
Plastic wrapping offers a better compaction of the package of lids than the one we get with paper bags. Since it is a heat-shrinkable plastic, it achieves total adaptation to the shape of the lids and wraps it better. On the other hand, paper bags have a greater tolerance between the lids and the wrapping paper, which can cause problems with the movement of the lids inside the bag.
The paper bags can be reused once the lids have been removed. However, this does not happen with plastic, since to take out the lids it is necessary to break the wrapping, making it no longer usable.
From an economic point of view, plastic is much less expensive than paper. This parameter can be decisive when making a decision on the type of packaging material to be used to wrap our lids, especially when no other criteria are involved.
8. Environmental impact:
The raw material for producing paper is wood, a renewable and unlimited resource. In contrast, plastic packaging is derived from oil, an increasingly limited and expensive resource. In addition to being reusable, paper packaging is recyclable: paper is a material that can be recycled up to six times, in fact, more than 80% of paper produced in Spain is made from recycled paper. Plastic is also recyclable, but its process is more complicated and expensive.
Moreover, if a paper package ends up in nature, it would not damage the ecosystem. Being a natural product, it would biodegrade in a period of between 2 and 5 months, without harming the environment. On the contrary, plastic containers are not biodegradable and take more than 400 years to disappear from the ecosystem. The carbon footprint in all processes of the paper life cycle is negative (they absorb more CO2 than they emit to the atmosphere), making them the most ecological option.
The paper bags offer a packaging with infinite creative possibilities, providing the product with differentiation from the competition. In addition, they offer more facility to print the brand or any graphic design on them: logo, references, bar codes,…
If you are interested in getting help from Autorema with the bagging, wrapping or debagging of your metal caps, please contact us and we will advise you with no commitment.
In addition, if you are interested in paper bags to pack your lids, do not hesitate to contact Tecnopapel Murciano, specialists in packaging for the can making industry.