Paper production. Depending on what type of paper must be obtained in the production process as raw materials use of cellulose fibers, wood pulp or a mixture thereof. Woodfree paper – the best quality and expensive, it has a high whiteness and strength. Paper made entirely from wood pulp, as Typically, the lowest quality. Niche between the two main types of paper is a mixture of cellulose and wood pulp, which are taken in a 1:1 ratio. The technology of the modern production of paper is quite simple. Floured cellulose fibers mixed with wood pulp, sizing agents (usually calcium carbonate) and a number of fillers.
For printing paper used blanched ground kaolin, for coated – Titanium dioxide, for special types of paper – zinc oxide. Fillers attached paper smoothness and flexibility, reduce its transparency and porosity. Then the pulp is fed to the grid of the paper machine for the formation of a thin fibrous layer. In the press-section of the machine pushed excess water, after which the tape is supplied to the drying part. There shall drying fabric and surface sizing, if necessary production of paper for offset printing or other moisture. The last section of the machine is called finishing.
Polished cast-iron cylinders compacted paper, lining the surface, and then going on to wrap tape rolls. To improve the quality of the surface used pigmentation or Coating – the application of the coating layer. In the first case of its thickness does not exceed 14 g/m2, in the second up to 40 g/m2.