According to different combinations, corrugated cardboard can be divided into the following five types:
1. Cardboard composed of a layer of core paper and kraft card is called "corrugated cardboard". Corrugated cardboard is generally only used for cushioning, spacing and wrapping irregularly shaped objects.
2. The cardboard composed of one layer of core paper and the upper and lower layers of kraft cards is called "single-pit cardboard".
3. The two-layer core paper sandwiched in the three-layer kraft card is called "double-pit cardboard". Double-pit cardboard can be composed of pit paper with different pit widths and different paper qualities, such as "B" pit paper with "C" pit paper.
4. The three-layer core paper sandwiched in the four-layer cowhide card is called "three-pit cardboard".
5. Extra-strong double-body paperboard is developed from single-pit paperboard, and the middle layer of core paper is made of two thick core papers laminated together.
