A standard sheet of corrugated board is made with two main components: linerboard and corrugated fluted paper. The sheet of fluted paper is sandwiched between an outside and inner liner which is then glued to the flat liner paper with starch.
When searching for a corrugated case you will generally see a description of the board as B125KT, which is a shorthand description of the board grade, paper weight and fluting size.
B = fluting Size
125 = Paper weight
KT = Kraft/ Test Paper (Outer/ Inner Liner)
The most common papers used to create stock boxes are a combination of Kraft and Test paper, as detailed above. Kraft paper is made from virgin fibres using softwoods from sustainble forests. The nature of this paper makes this paper the most commonly used outside liner. Test paper is made predominately from recycled papers which give it its mottled effect and is often the most common inner liner used in creating corrugated cardboard.
It is the size of the flute and the weight of the paper used, which determine the strength and performance of the board, which translate through to determine the same properities of the constructed corugated case.
All of the listings on Boxed-Up will detail the board grade used for each of our stock and clearance boxes. If you want to gain a better understanding of the board grade breakdowns supplied from suppliers, read more from our blog.