How to improve the opacity of low basis weight offset paper?

The opacity of printing paper is a basic property and one of the very important indicators. Opacity is important for offset paper, especially low-basis weight offset papers. Transparency paper that is used for double-sided printing or writing will be unusable due to print-through. Therefore, a certain opacity is required for printing and writing paper used on both sides to ensure the quality of the printed matter.
woodfree paper
There are many factors that affect the opacity of paper, among which are the basis weight of the paper, the chemical properties of the pulp, the bulk of the paper, the whiteness of the paper, and the effect of fillers. Paper mills generally increase the opacity of paper by adding filling to increase the ash content of the paper or increasing the amount of mechanical pulp, but the increase in the amount of paper ash and the increase in the amount of mechanical pulp will reduce the physical strength of the paper, and the paper machine is prone to breakage during operation.

In order to ensure the high strength advantage of the low-weight original white woodfree paper, we use the method of adding dyes to improve the opacity of the low-weight original white offset paper without affecting the whiteness and color of the paper.

Adding three colorants, royal blue, magenta violet, and magenta yellow, will increase the opacity of the paper. The whiteness of the paper with the addition of magenta yellow decreases obviously, and the addition of royal blue and magenta violet has no obvious effect on the whiteness. Both magenta violet and royal blue will greatly reduce the b value, and the color of the paper will change significantly.

In the production of low-weight original white offset paper, the original production process is not changed, and the whiteness and color of the paper are relatively stable, and the opacity of the paper can be improved only by adjusting the amount of dyes royal blue and yellow added.

offset paper

 


Post time: Oct-17-2022