In 1884, Swedish chemist Karrh Vegeta developed a process for beating wood chips into strong paper resistant to tearing, cracking. He named it Kraft paper. The corrugated board consists of three layers of brown kraft paper. It is a hard, strong, and lightweight material.
Most of the items in your favorite supermarket, discount store, or shopping center are shipped in boxes made of corrugated cardboard. Because the corrugated board is a widely used packing material, millions of tons of corrugated board are used to protect and display products every year.
In 1992, the United States produced more than 25 million tons of corrugated cardboard. Another 6 million tons of non-corrugated or paperboard were produced for folding cartons.
What is the main material?
Pine is the main raw material for making corrugated boards. When the trees are mature, they are harvested and stripped of their limbs; only the trunks are trucked to the pulp mill. At the plant, harvested tree trunks are subjected to a kraft paper process, also known as the sulfate process, because the chemicals are used to break down the sawdust into fibrous pulp. After pulp processing, the fiber is directly sent to the paper machine for forming, pressing, drying, rolling into a wide width.
What is the Manufacturing Process?
Making pulp from pine sawdust
The manufacture of corrugated cardboard boxes began with the pulping of wood chips in the Kraft paper (Kraft) process. First, the trunk is stripped of its bark and torn into small pieces. The fragments are then placed in a large high-pressure tank called an intermittent digester, there they are cooked in a solution or liquid made from sodium hydroxide and several other ionic compounds such as sulfate, sulfide, and sulfite. These strongly alkaline chemicals dissolve, and lignin, lignin, is a glue-like substance that holds individual wood fibers together in the trunk.
Making Kraft paper
After additional cleaning and refining steps, the consistent wood pulp is pumped to the paper machine, these machines consist of a wire mesh in which the paper is initially formed. The paper is then fed into giant steam-heating rollers and wide blankets to remove moisture.
Transportation
Corrugated kraft paper rolls are available in a variety of sizes, the most common sizes being 67 inches and 87 inches. An 87-inch heavy roll can weigh up to 6,000 pounds
Storage
In factories, Kraft paper is divided into different grades for use as a medium and as a liner. These different grades of corrugated cardboard can be made by combining different grades of Kraft paper.
There are two key steps in corrugated board manufacturing:
Make Kraft paper and corrugated board.
Kraft paper consists of beating wood chips into a pulp and then removing water through a large amount of steam.
Corrugated paper is also done in machines using heavy-duty rollers. A roll of cardboard is corrugated and then glued between the other two layers (linings) by the same machine. The glue is then solidified by heating the cardboard.
Forming the blanks into boxes
At the end of the corrugating machine, the slitting machine cuts the cardboard into large pieces called blanks. The blanks pop out of the slicer like chunks of toast, slide into the auto stacker and load them onto a large rolling platform. From here, they are transported to other machines, where they are converted into finished containers. Intelligent production of box blank.
Printing dies and die-cutting patterns
Prepare in the pattern shop on large and soft rubber or tin plates. The die and pattern are loaded onto the Flexo Press’s large drum, through which the blank passes automatically. As each blank passes through the flexo roll, it is trimmed, printed, cut, scored, and then folded and glued in the printer-folder-gluer to form a box.
In the future, corrugated boxes will be used for recycling and other public welfare activities.
