Knowing excatly the characteristics of the cartonboard for your packaging is essential for choosing the proper type and weight to meet our needs. Considering the cross direction stiffness, the machine direction stiffness, as well as the water absorption and resistance allow us to define which cartonboard is suitable for the packaging that we have to produce and which cartonboards to avoid.
Each packaging, in fact, must take into consideration the importance of meeting certain requirements in order to be suitable for storage and transport.
Especially, the main requirements that individual boxes and any other type of packaging must meet include stackability, handling and protection during transport
Crucial properties of cartonboard
Stacking requires resistance to vertical crushing which can be controlled by static or dynamic loading of a pallet, transport packaging or single package. For the handling of external packaging, impact resistance and resistance to uneven compression under mixed loading is required.
By transport- related stresses we generally mean shocks, which can be simulated with tests on flat and drop tests. A special kind of padding may be required for sensitive products. To find out if this is necessary, tests can be carried out on a shaking table, driven with adjustable frequency, and the results of transport tests under real conditions can be recorded. The vibrations cause rubbing and friction of the surfaces that are in contact with consequent damage to the packaging.
These requirements must also be met in frozen (-20°C), cold (0 to +3°C), very humid or wet environments, and in very hot and dry climatic conditions.
Practical instructions for distribution and storage
The following factors are of prime importance for the efficiency of distribution and storage:
- cartonboard resistance
- structural design of the box
- type of product (i.e. whether the wrapped product contributes to the stability of the packaging or not)
- resistance and structure of the transport packaging
- stacking on pallets. The dimensions of the transport packaging can be checked by computer, in order to ensure maximum loading capacity of the pallet. In this way it is possible to optimize the stacking of the packaging, avoiding the formation of empty spaces.
However, particular conditions of storage and distribution require few more remarks.
Special distribution and storage conditions
We have already deepened in this article how frozen and chilled foodstuffs require high performance to the cartonboard that packs them and this is mainly due to the storage conditions of the same.
In fact, when the packaging is stored or intended for frozen, humid or very hot environments, the rules to be respected to keep the characteristics of the cartonboard intact are different.
1. Ice cream and frozen food
In these cases it is necessary to maintain a storage temperature of about -20 ° C. It must be checked that printing and painting do not crack at those temperatures.
2. Refrigerated food
For refrigerated foods, the packaging must maintain a storage temperature between 0 and +3°C. The greatest danger, in this case, is due to the high humidity of the air, which can cause an increase in the humidity of the cartonboard and a consequent loss of rigidity and strength. There are different ways to reduce this risk, such as using overpackaging for products packaged in a plastic or aluminium tray, or pack the product in laminated carton tray closed with a plastic coated, printed and heat-sealed cartonboard lid. The resistance of the cartonboard to moisture can be improved with the following actions:
- Super-gluing: total gluing of all layers of the cartonboard: this arrangement rejects the absorption of water along the edges (absorption that is measured through the Wick test)
- Functional coating with cartonboard, plastic or aluminum film, wax or water-repellent paint that rejects water absorption from the surface (absorption that is measured through the Cobb test)
3. Moisture and wet
The resistance of cartonboard to moisture can be increased, as seen in the previous entry.
4. High temperatures of the environment
The main problem is the tendency to “pack”, i.e. the adhesion of the sheets or packages to each other. To avoid this inconvenience, a suitable barrier and appropriate inks and paints must be chosen for the cartonboard.
So, how to be sure to choose the right cartonboard?
Rely on our Internal Sales team to provide the best advice regarding cartonboard and grammage!
Get in touch with us for a non- binding chat or start from the technical sheet of our 100% barrier cartonboard suitable for direct contact with food: Metsä Board PRIME FBB EB
