A production process of advanced coated white paperboard

Abstract

The invention belongs to the technical field of a coating white paper board production method. A high-grade coating white paper board production process comprises the steps of pulping and paper making, wherein the pulping step adopts the separated and segmented beating modes including surface pulp beating, lining pulp beating, core pulp beating and bottom pulp beating, the paper making step comprises a net part, a squeezing part, a drying part and a coating and QCS (quality control system) control system, and in addition, a film transfer sizing machine is added in the middle of the drying part. Modes completely different from the traditional mode are adopted in the coating white paper board beating process and the paper making process, the process improvement is carried out on several key control points, the technical indexes are correspondingly regulated, the energy consumption is reduced, and the subsequent paper making quality is also improved, so the quality of finished product paper is always controlled to be higher than the nationally specified A grade (high grade) index.

Description

technical field [0001] The invention belongs to the technical field of preparation technology of coated white paperboard. Background technique [0002] In recent years, with the rapid development of the national economy, the quality requirements of coated white board paper are getting higher and higher, and the market competition is becoming more and more fierce. Many quality indicators of coated white board paper, especially the ink absorption during printing, are mainly determined by the coating. The inhomogeneity of the coating structure may lead to uneven absorption of ink and will reduce the printing effect. Therefore, obtaining a good and stable coating weight is of great significance to improving the quality of white board paper. At present, the coated white paperboard has the following problems: [0003] (1) The tightness is too large, usually 0.85g / m 3 Above, excessive tightness results in low stiffness. [0004] (2) The ink absorption is too high, sometimes as ...

AI Technical Summary

Problems solved by technology

[0003] (1) The tightness is too large, usually 0.85g / m 3 Above, excessive tightness results in low stiffness

[0004] (2) The ink absorption is too high, sometimes even as high as 40%, generally around 38%, resulting in low printing gloss of coated paper

For printing factories, if the ink K&N value is too high, the ink consumption will be high no matter what printing method (offset printing, screen printing, etc.) visual effects

Generally speaking, the ink absorption is best controlled at 20-26%, if it is lower than 18%, it will affect the printing speed and easily stain the printing surface

[0005] (3) The surface strength (IGT) is unstable, sometimes it can exceed 2m / s, and sometimes it is as low as about 1.2m / s, and it needs to be stably controlled at 1.8-2.2m / s

[0006] (4) The Cobb value is sometimes too large, which is easy to affect the water resistance of the coating and the underlying paper surface

[0008] (6) The smoothness requirement of coated white paperboard is relatively high, which can generally reach more than 150s, but for printing, it is only about 80s at present

However, after several years of operation, the pulp concentration can only be maintained at 16-18%. The main reason is that the screw used for thickening and the screen drum for dehydration are worn out, resulting in a larger gap between the screw and the screen drum, which is harmful to the slurry. The effect of extrusion and concentration becomes worse, reducing the pulp concentration; second, the output of the papermaking workshop continues to increase, resulting in a relatively low thermal dispersion processing capacity. In order to ensure the supply of core pulp, generally choose to enlarge the outlet and sacrifice the concentration. As the gap between the screw and the screen drum in the previous article becomes larger, the passing speed of the pulp is further slowed down, thus forming a vicious circle; third, the number of domestic waste paper recycling continues to increase, the freeness of the pulp decreases, and the fibers are too short, making The dehydration of the pulp decreases, and at the same time too much short fiber blocks the screen drum, which seriously affects the processing effect of the screw extrusion equipment

[0011] The emergence of the above situation has seriously affected the normal production of the workshop, which is mainly reflected in the following aspects: (1) The concentrated concentration is too low, resulting in poor rubbing effect of heat dispersion, ink dots and ink remaining in the slurry There are more wax spots, which will reduce the dehydration efficiency of the forming wire during papermaking, increase the probability of paper web breakage, and affect the normal production of the paper machine and the stability of the quality of the finished paper

(2) Because the slurry concentration is too low, the moisture carried in the slurry passing through per unit time will increase, resulting in a large proportion of the steam consumed by the thermal dispersion system when heating is consumed in the heating of water, and the equipment The temperature rise caused by kneading the slurry also becomes less noticeable, both of which lead to a significant increase in the steam consumption of the thermal dispersion system

Especially for waste paper pulp, the source is complicated and the quality fluctuates greatly. If the beating degree is not controlled properly, it will have a great impact on paper quality and energy consumption.

[0014] At present, the commercial pulp board of flour pulp is mixed and beaten. Although this operation is more convenient and can protect short fibers from excessive cutting, it is not conducive to the uniform formation of long fiber pulp when it is online.

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