1. Quantitative
It refers to the weight per unit area of the paper, expressed in g/m2, that is, the weight of one square meter of paper. The basis weight of the paper determines the physical properties of the paper, such as tensile strength, tearing, tightness, stiffness and thickness. Therefore, according to the characteristics of the equipment, arranging the printed parts corresponding to the quantitative and its performance for production can better reduce consumption and improve product quality and equipment efficiency.
2. Thickness
It is the thickness of the paper, and the unit of measurement is usually expressed in mm. Thickness has a close relationship with basis weight and tightness. Generally speaking, if the paper is thicker, the basis weight is higher, but the relationship between the two is not absolute. Some papers are thin, but their basis weight is equal to or exceeds that of thicker papers. This shows that the tightness of the fiber structure of the paper determines the basis weight and thickness of the paper. From the perspective of the use effect, it is very important that the thickness of the paper is uniform. Otherwise, it will affect the automatic paper feeding and gluing uniformity.
3. Tightness
It refers to the weight of the paper per cubic centimeter, in g/cm3. The tightness of the paper is calculated from the basis weight and thickness according to the following example formula: D=G/d*1000, where: G represents the basis weight of the paper; g is the paper thickness of.
Tightness is a measure of the degree of tightness of the paper structure. If the tightness is too large, the paper will be brittle, the opacity and water absorption will be significantly reduced, and it will not be easy to dry.
According to the above formula, it is easy to calculate the thickness of the cardboard. The formula is: d =G/D.
4. Stiffness
It is the performance of paper against the pressure of another object, and it is also the performance of paper fibrous structure.
5. Smoothness
It refers to the degree of unevenness on the surface of the paper, expressed in seconds and can be measured. The detection principle is: the time it takes for air of a certain solvent to pass through the gap between the surface of the glass plate and the surface of the sample under a certain vacuum and pressure. When the paper surface is smoother, the air passing speed is slower, and vice versa, the air passing speed is faster.
6. Expansion rate
It refers to the size variation of paper after it absorbs moisture or loses water. The softer the fiber structure of the paper and the lower the tightness, the higher the expansion rate of the paper; on the contrary, the lower the expansion rate.
7. Water content
The moisture content in the cardboard. Generally speaking, it is standard. The moisture content of double gray cardboard is 8-12%.
8. Vertical and horizontal
It refers to the direction in which the paper fiber organization is arranged. In the papermaking process, the fiber runs along the paper machine in the longitudinal direction of the paper. It can be identified from the sharp angle presented by the net marks. Vertical to the vertical direction is the horizontal direction, the vertical paper texture uses a small deformation value, and the horizontal paper texture uses a large amount of expansion and contraction variation.
9. Air permeability
Generally speaking, the thinner the paper and the lower the tightness, the greater the air permeability. The unit of air permeability is ml/mim (ml/min) or s/100ml (seconds/100ml), which refers to the amount of air passing through the paper surface in 1 minute or the time required to pass 100ml of air.
10. Pros and cons
In papermaking, the pulp adheres to the steel mesh and is qualitatively filtered and dewatered. In this way, if the fine fibers and fillers are lost with water on one side of the net, net marks are left, and the paper surface is thicker. The other side is dense without netting. Smooth, so that the paper has a difference between the front and the back. Although the paper is dried and calendered during production, there are still differences between the front and the back.
