Nowadays, many industries need to use cartons, but if the hardness is not good, the items contained in cartons will be easily deformed or seriously damaged. So, how to enhance the hardness of cartons? This can be achieved by:
1. Additives
This method is to add a variety of chemical crystals before and after papermaking to improve the adhesion, so as to improve the compressive strength of corrugated boxes. These additives include corn, starch, glue, adhesives and heavy metals, as well as plastics and urea (formaldehyde) resin. Sometimes, chemical spraying is also used to strengthen the cardboard.
2. High voltage
The forming method of high-pressure paperboard is also a method to enhance the strength of paperboard in the process of papermaking. The compression point on the paper is expanded to compress the paperboard tightly. The tighter the cardboard structure, the greater the strength. The forming of high-pressure paperboard also helps to squeeze more water from the pulp, but the key is to make a tighter paperboard to improve its compressive strength.
3. Crosslinking
Crosslinking is a processing method that changes direction in papermaking process. Usually, the paper runs in parallel in the longitudinal direction. After the box is formed, the horizontal direction is around the box, which is the bad direction for the box to resist the pressure. Cross linking makes many of them move 90 degrees to the machine direction, and the processing result is that many of them move vertically to the box edge, so as to increase the stacking strength of cartons without increasing.
4. Lamination
The method for enhancing the strength of the corrugated box is to build on two or more layers; Core paper laminated on the basis of. The adhesive may be a simple corn starch adhesive that produces a strength core paper to be sandwiched between cross-linked, pressure formed or conventional strength paper.
