Is it possible to have a humidity proof cardboard? Yes, but it’s not something one should improvise.
Here’s what you need to know before choosing it.
In warehouses where moisture rate is higher than normal, the main problem is that condensation can damp the interlayered cardboard pads. Depending on the bottling and storage area and the seasonal temperature, the situation may get even worse, especially if your production refers to products intended for refrigeration.
This is not relevant when we talk about few droplets, but if the moisture and condensation level rises then the cardboard, even the thickest one, is likely to absorb too much water, thus becoming totally unusable. Worse, its degradation could turn in an organizational cost far from negligible.
Think about all the situations when you have to “unpack” entire pallets reorganizing the fitting. Handling of men, spaces, new cardboard and, at the end, a new rearrangement of the products.
Paperboard for moisture-resistant interlayers and packaging
The solution to this problem is in the use of a special kind cardboard obtained by adding a compound of cationic glue with an aqueous base to its mixture. The glue, bonding to the cardboard, creates a sort of polymer net able to prevent the natural absorption of water, at different degrees.
Normally, recycled cardboard is created by the passing of the dough through the pressing drums. In the case of paperboard, the “waterproofing” compound (this helps us to understand the process) is added prior to the passage between the drums.
The glue is added “in mass”, as the paper technicians like to say. It means that it’s added when the dough of the paper and its additives is extracted from the pulper to be conveyed in a mixer, and all the compound is still in a liquid or semi-liquid phase.
Only then, the dough is conveyed into the drums that create the now collated layers of recycled cardboard. To be specific, the collated layers are the most external, acting like a coat on both sides, being the part in contact with the goods.
That’s how you get the perfect product for collated interlayers.
How do you measure the moisture resistance of the collated cardboard?
Many people like to think that making paper and cardboard is still a kind of art, but today it’s more of a set of different scientific disciplines (from chemistry to physics, from electronics to mechanical engineering, just to name a few) that dictates how a sheet of cardboard should be made.
In the case of interlayers, through a series of measurements is possible to obtain a specific indicator, to understand if and how the final product is effective against moisture: the absorption factor.
This data is detected through an experimental test called “COBB 60 Test”, an international level industry standard. The absorption factor is the weight difference of a square decimeter of cardboard before and after being put in contact for sixty seconds with a deciliter of water, after one minute, the weight of the cardboard is measured and compared to the initial weight, prior to the test.
The difference in weight determines the absorption factor.
For a better understanding: a square decimeter of 350 gr not collated cardboard in contact with a deciliter of water, doubles its weight after sixty seconds becoming 700 gr. The weight of a same sized cardboard, with the basic collated mixture, increases only by 200 gr.
By increasing the ratio of cationic glue in the dough we lower the absorption factor, improving water resistance.
Now the question is: can we have a card with COBB factor 60 equal to zero, totally “water proof”?
Of course we can, but we are talking about a product that deviates from normal cardboard becoming something else and whose cost must be worth the effort. For the applications in the beverage and food distribution industry, collated interlayers are already an excellent solution.
The convenience of collated interlayers compared to traditional ones
Here are the advantages of a collated interlayered cardboard.
Less waste of material, improved organizational efficiency and equipment. In addition, less returns for poor equipment with a consequent cost reduction, including those of transport. Not to mention the safety of knowing that your product is intact when he reaches the distribution.
Request a sample of our collated interlayers
There is no better way than to experience first-hand the quality and strength of this kind of cardboard for interlayers and packaging.
Contact our sales department to explain your specific need and evaluate a sample test for your production.