Basic knowledge of carton paper (4)

· Tensile strength is between 30 and 40% RH. As the humidity increases, the humidity continues to increase, and the tensile strength decreases sharply.

• The elongation increases with the increase of the humidity, and the longitudinal change of the base paper is large horizontally.

• The fracture strength and tensile strength are the same, the humidity increases, and the rupture strength decreases. The reduction ratio is smaller than the tensile strength.

• Tear strength increases with increasing humidity in both the longitudinal and transverse directions, but decreases again in the extreme high humidity range.

Corrugated board production requirements for base paper
The corrugating medium is pressed into a corrugated shape on a corrugator and then coated with corrugated corrugation and corrugated cardboard to form a corrugated cardboard. The appearance and strength of the corrugated medium is good or not, and is closely related to the base paper. The requirements for base paper are as follows:

RLINING ABILITY

Corrugating medium paper presses hundreds of corrugated irons in a minute at the time of pressing the corrugated medium, so the corrugating medium is very important. Therefore, the plasticity of the corrugated medium paper is very important, and it can be made into a straight and strong corrugated fiber when it reaches a certain standard. Recently, high-speed corrugated paper machines have been continuously increased and the speed has been continuously improved. For example, poor quality of the base paper is enough to affect the operation of the machinery, resulting in a decrease in production efficiency.

Raw paper uniformity

Kraft paperboard and corrugated medium paper, whether vertical or horizontal, have a large difference in water content, which can cause serious problems such as poor adhesion, paperboard curling, and falling down. The uneven thickness leads to poor operation adaptability, and the physical strength of the finished product is greatly affected. Therefore, the uniformity of moisture and thickness of the base paper is considered as one of the most important items in the acceptance and use of the base paper.

The appearance of the base paper

The appearance of the base paper requires the formation of a smooth surface with no holes, cracks, contamination, and other obvious disadvantages. In addition, the color of the surface of the cardboard paper is also a project worthy of attention. The original function of corrugated cartons in the course of their use was to achieve the integrity of the contents of their contents. Now it has evolved not only to protect the contents, but also to take up the responsibility of promoting sales and inspiring consumers' desire to purchase, as it is required in corrugated cartons. The surface is finely printed, and the hue of the cardboard surface is sufficient to affect the printing effect. However, in the papermaking process, due to the difference in the size of the slurry, such as excessive requirements for the surface hue, there are practical difficulties. In the inspection and acceptance of the surface color of container board paper, the upper limit of control and the lower limit of control shall be established, and the design of the printed pattern shall be supplemented with the design of the printing ink. The cooperation of ink selection may achieve the purpose of beautification.

The strength of the base paper

The type of Corrugated Box, regardless of whether it is often used at home and abroad as the main classification criteria based on bursting strength (burstting force) (burst), the rupture strength of the corrugated cardboard is determined by the rupture strength of the cardboard.

The compressive strength of corrugated boxes, also known as box pressure, is derived from the ring pressure strength of linerboard and corrugating medium. The moisture content of raw paper has a great influence on the operation of corrugated paper machines. Therefore, the base paper's strength and moisture content are very important items in the inspection and acceptance operations.


Source: Export Goods