Cardboard is one of the most widely used materials worldwide, along with plastic and paper, but we usually do not know where the cardboard comes from and what its manufacturing process is.
With the cardboard different products are made like the boxes that help to protect objects or food. It is a clean, ecological, resistant and durable material.
Thanks to its characteristics, it is considered a recyclable and reusable material, so it can be considered environmentally friendly.
A cardboard box can be reused to store new objects, make crafts. When they are thrown away, they go to the blue recycling container so that the processing companies can obtain the cellulose fibre and manufacture new cardboard products.
In this article we will explain where cardboard comes from, manufacturing materials and the steps companies follow to obtain it.
Table of Contents
What is cardboard?
Cardboard is a material obtained from the processing of cellulose pulp, which comes from pulpable wood trees. It can also be made from the extraction of cellulose from recycled paper or cardboard.
The wood used to extract the cellulose fibre is from trees such as pine, eucalyptus, larch, spruce and fir. These trees are ideal for their rapid growth.
The cardboard is made by placing several layers of the paper made of cellulose fiber, interspersed and arranged one over the other.
By having several layers, the cardboard is stronger and more durable. In addition, in the manufacture of cardboard, there is a tendency to alternate a layer of smooth paper with a corrugated one to create more firmness.
Characteristics of the cardboard
Regardless of where the cardboard comes from or its type, the thickness and volume they have when they are manufactured will determine their use and the weight they can withstand.
In addition, cardboard has other characteristics that determine its quality and reliability as a material.
These particularities are:
Grammage
Grammage is the measure used to express the weight of the cardboard. The weight of the cardboard is established in grams per square meter.
The cardboard that is produced to make boxes or other types of packaging, for example, must have a weight of between 160 and 600 grams per square metre. So that they are resistant to the weight.
Thickness
The thickness of the cardboard sheets is the distance between its two faces. It is measured in thousandths of a millimetre.
The objects made from the cardboard sheets are between 300 and 800 thousandths of a millimeter thick.
Density and calibre
The density of the board refers to the level of compression to which it is subjected. Density is expressed in kilograms over cubic meters.
As for the calibre, it expresses the surface of the cardboard expressed in square metres per 10 kilograms.
Durability of cardboard
Due to the characteristics of the cellulose fiber from which the cardboard comes from and the process of its elaboration, a material is obtained that has a resistance and the capacity to be used for a long time.
Resins are also used to cover the cardboard and make it waterproof. For specific uses, special treatments are applied to prevent the growth of fungi and mold.
Stiffness
Cardboard has the ability to retain its shape even when lifted by one of its edges with weight inside. It also tends to return to its initial position when folded.
This is related to thickness and weight. The thicker the cardboard, the greater its rigidity. On the other hand, the weight can vary according to the weight and the surface of the cardboard.
Adaptability
Cardboard is a versatile material that can be used to make products, such as boxes, that can be reused for other purposes.
Prints can be made on the cardboard, so anyone who buys it can give it their personal touch and make multiple objects from the virgin cardboard.
Finally, as it is a light material, it can be used to make different crafts.
Sustainable and recyclable
Cardboard is a material that can be reused because of its resistance and durability, and after it has reached its useful life it is discarded in the blue recycling container to create new cardboards.
During the manufacturing and procurement process, only 40% of carbon dioxide is emitted into the environment, and a smaller percentage is produced from recycled cardboard.
Manufacturing process Where does the cardboard come from?
Cardboard is a simple material to obtain and its manufacturing process is economical, making it ideal for packaging products and making other objects.
After finishing the process of obtaining the cardboard, they are sent to companies that make objects with the cardboard or boxes are manufactured in the same industries.
Next, the steps that where the cardboard comes from that is used daily are:
Obtaining raw material
Pulpwood trees are cut down for wood. That wood is processed and cellulose fibre is manufactured.
Pine and eucalyptus trees, two fast-growing species of trees, are preferred for the manufacture of cardboard, making them ideal for the manufacture of cardboard.
When paper and cardboard companies cut down a tree – where the cardboard comes from – they have to plant three more, so there is no deforestation of the forests.
In addition to the trees, the cardboard thrown in the recycling points is collected to be reused.
Kraft process
In this process the tree trunks are cut into small pieces. These pieces are processed in shredders.
These shredder pumps are high pressure tanks that dissolve one of the fibers of the wood called lignin, and then clean and refine them.
When refined, the wood is placed in a Fourdrinier machine to start the cardboard making process, by flattening the cellulose fiber creating a long paper strip.
Machine where the corrugated cardboard comes from
The corrugating machines are 91 cm long. They have large rolls that corrugate the paper obtained from the Fourdrinier machines.
The machine contains a roller that preheats the paper and a corrugating roller that has grooves to fold the paper and make the corrugated board.
Gluing
The cardboard, which comes from the machine where the corrugated cardboard comes from beforehand, is placed between two layers of paper in the form of a roll.
When the cardboard is joined to the two sheets of kraft paper, they are glued with starch glue and flattened with rollers so that it remains firm and does not come off.
Cardboard recycling
In Spain, more than 47% of the waste in recycling containers belongs to the blue container that includes paper and cardboard. Thanks to this, more than one million tonnes of paper are recycled in the manufacture of new paper.
The paper and cardboard that reach the green points where they are separated and sent to industries of companies that produce these items.
Cardboard can only be recycled six times to produce new cardboard, because the cellulose fibers go through a process in which they are cut and frayed to obtain the paper from which the cardboard comes.
This causes the fibre to get smaller and lose its strength, so the paper made with these fibres could break during the manufacturing process.
There are also companies that combine new cellulose pulp with recycled cardboard pulp to obtain a good result and reuse the cardboard more to make a positive contribution to the environment.
