Reasons for paperboard delamination and its treatment
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(1) The degree of beating of the slurry of each layer is quite different. Influencing the inconsistency of the water in the slurry layer, the foaming site generally appears after passing through the nip between the two pulp layers with widely varying degrees of beating. Treatment: control the pulping degree of each pulp layer within 10SR, or increase the internal and external water level difference in the pulp layer with high beating degree, and strengthen the dewatering capacity of the vacuum suction box;
(2) The pressure of the roller line is improperly adjusted. Treatment: Appropriately increase the line pressure of the front roller at the foaming site to reduce the foaming
Line pressure of the nip;
(3) The amount of slurry on the net, the level of the slurry on the Internet, the improper control of the water level difference inside and outside the net, and the vacuum of the vacuum suction box are too low, so that the moisture content of the wet paper sheets formed by each layer material is very different, in the network department Will produce bubbles. Processing: adjusted according to the situation
Section
(4) The dirt and oil blocks in the net department and the wool layout department cause poor local dehydration and permeability, and the air between the felt and the paper sheet. The water is not discharged well. In this case, foaming occurs at the preload. Treatment: cleaning copper net (plastic net), felt;
(5) When the volt roll or the mesh surface has a dent, it will bring in excess air and water, and will form a bubble by pre-pressing. Processing: more
Changing rolls or nets;
(6) The partial pressure of the volt-rolling water squeegee, when the water-blocking cloth is not flat or there is a hole, the water that is pressed out makes the wet paper sheet "back"
The phenomenon of tidal phenomenon destroys the local layer combination, and bubbles are generated in the back pressure zone, and embossing is also caused in severe cases. Treatment: cleaning, adjusting the water squeegee or replacing the water-blocking cloth; adding after each cage A vacuum suction suction box can reduce the moisture of each layer of wet paper, which can reduce foaming and embossing.
(7) The drying temperature curve of the drying cylinder is not adjusted well, the temperature of the drying cylinder rises sharply, and the water vapor generated inside the cardboard cannot be very
It escapes quickly and stays between the layers of paper with weaker fiber bonding, causing delamination of the paperboard. Treatment: adjust the drying temperature curve of the drying cylinder. The temperature of the first two drying cylinders should not be too high, generally 90 to 95 °C. Gradually increase to 120 ~ 125C.