Nowadays, many industries require the use of cardboard boxes, but if the hardness is not good, the items stored in cardboard boxes are prone to deformation or serious damage. So, how can we enhance the hardness of cardboard boxes? This can be achieved through the following points:
1. Additives
This method involves adding various chemical crystals before and after papermaking to enhance the bonding strength and thus improve the compressive strength of corrugated cardboard boxes. These additives include corn, starch, glue, adhesives, heavy metals, as well as plastics and urea formaldehyde resins. Sometimes, the method of chemical spraying on the outer layer of cardboard boxes is also used to reinforce the cardboard.
2. High voltage
The high-pressure cardboard forming method is also a method of enhancing the strength of cardboard during the papermaking process. Expand the compression points on the paper to tightly compress the cardboard. The tighter the cardboard structure, the greater the strength. High pressure cardboard forming also helps to squeeze out more moisture from pulp, but the key is to make the cardboard tighter and improve its compressive strength.
3. Crosslinking
Crosslinking is a processing method that changes direction during the papermaking process. Usually, paper runs longitudinally parallel, and this type of box is horizontally wrapped around the box after forming, which is a bad direction for the cardboard box to resist pressure. Crosslinking causes many to run at a 90 degree angle to the machine direction, resulting in many being perpendicular to the top and bottom of the box edge. This increases the stacking strength of the cardboard box without increasing it.
4. Layering
This method of enhancing the strength of corrugated cardboard boxes is based on two or more layers; On the basis of core paper lamination. The adhesive can be a simple corn starch adhesive that produces a strong core paper to be sandwiched between cross-linked, pressure formed, or conventional strength paper.
