Corrugated board serious degumming solution

There are three major factors in the production of corrugated board: temperature, paste, and tension. For the operator, it is necessary to adjust these three elements to the best conditions to produce high-quality corrugated board. Corrugated board degumming is also seriously related to these three elements.

(a) The binder raw material does not meet the requirements, especially the content of the gray powder in the starch has a great influence on the adhesive strength of the paste. Only the raw materials used for paste making meet the standard requirements to produce a qualified paste.

Solution: Test the paste into the factory and use qualified paste.

(2) The ratio of the paste and the mixing time must be strictly enforced according to the requirements. If the paste is too thin and thick, it can cause poor adhesion of the paperboard. Paste is too thin, is equal to add water to paper, easily absorbed by paper, low bond strength, easy degumming. The paste is too thick, the initial viscosity is slow, it is difficult to gelatinize, and the bonding quality is poor, resulting in degumming.

Solution: Strictly follow the mixing ratio requirements and mixing time requirements for paste making. The viscosity of the paste is strictly controlled. Under normal circumstances, the viscosity of the single-sided machine paste is 50 seconds to 60 seconds, and the double-sided coater is generally controlled at about 100 seconds, and the paste prepared on the day is used. The control of the viscosity also depends on the weather conditions, the quality of the paper, and the moisture content, depending on the accumulated experience of the operator.

(3) Temperature is the main factor affecting the bonding degree of the cardboard. When the temperature is low, the paste cannot be pasted, and the cardboard will be debonded. If the temperature is too high, the starch will be destroyed and degumming will also occur.

Solution: Paste paste temperature is generally 160 °C ~ 180 °C is appropriate, to reach this temperature range, we must first ensure that the steam boiler supply must be saturated steam, the pressure to reach more than 0.9Mpa. When the corrugated cardboard line is in operation, the paper needs to take a lot of heat, so that a large amount of saturated steam in each roller becomes condensed water, and the condensed water must be discharged in time. Therefore, in the circulation system of steam, the drainage system must ensure smooth flow. The position of the siphon in each roll should be correct, and the displacement of the trap should be 2 to 3 times that of the condensate. Every week, the trap outlet of the trap is opened for cleaning to ensure the smooth flow of the trap.

In operation, when the temperature is low, the operation speed can be reduced; when the temperature is high, the operation speed should be increased.

(4) The amount of glue applied affects the adhesion of cardboard. The amount of glue is too small, the adhesion is small, easy to open the plastic. The amount of glue is large, the moisture content is large, the gelatinization is not easy, the initial adhesive force is low, and the degumming is caused when dragged on the overpass. Under normal circumstances, the width of the glue line is preferably 1.5mm to 2mm.

Solution: Adjust the gap between the scraper roller and the glue roller properly. The gap between the rubber roller and the main corrugated roller is between 0.10mm and 0.25mm. When measuring, use a feeler gauge to measure the gap, and the left and right ends of the gap should be the same.

In addition, note that the squeegee blade on the squeegee roller must play a role. The glue on the squeegee roller must be scraped, and if it does not, it must be adjusted. After work every day, all the gluing rollers should be cleaned, and the glued place should be brushed with a soft brush to prevent the paste from drying and affecting the amount of glue on the second day.

(e) The parallelism of the rollers affects the cardboard bonding. In particular, the glue roller, the scraper roller, the corrugating roller, and the pressure roller are parallel to each other. Because the rollers are not parallel, the amount of glue is uneven and the adhesion is not good, so that the cardboard is easy to open.

Solution: The parallel of the rollers should be within 0.03mm and measured once a week. The method of measurement uses "carbon paper method" or "lead wire method". If it is found that it is not parallel, it should be adjusted immediately.

(6) As the corrugating roller wears badly, especially when the narrow-width paper is often processed, the center of the corrugating roller is concave, and the glue is not applied on the roller.

Solution: According to the degree of wear and tear of corrugated, take different methods to solve. When the middle height is still within the standard height, you can use the scrub to grind the two ends of the corrugated, so that the concave heart is reduced, can be coated with glue. When the height of the middle part is smaller than the standard, the corrugating roller must be repaired or replaced with a new one.

(7) The moisture content of the base paper affects the degree of bonding, resulting in open glue. In general, the moisture content of the base paper should be uniform, because the water content has a significant effect on the quality of the paperboard. This characteristic is wet expansion. About 1% change in water content, the paper will have a size change of 0.06% to 0.01%. The corrugated board produced by the assembly line may have a moisture change of up to 20%, and may produce a relative dimensional change of 0.9% to 2.0%, which may cause poor adhesion.

Solution: Adjust the temperature and preheating area of ​​each preheating component to ensure that the moisture content of the paper entering the single-sided machine is 9% to 12%.

(8) The pressure of the single-sided machine is improper, especially when the pressure between the pressure roller and the main corrugating roller is too low, causing poor adhesion of the cardboard and opening the glue.

Solution: Adjust the pressure roller cylinder pressure properly.

(9) Inadequate preheating causes poor adhesion to open the plastic.

Solution: When producing five-layer corrugated cardboard, it is very important to heat the surface of the triple heat engine. The upper roll should be preheated on the corrugated surface of the single-sided paper, and the middle layer should be preheated on the single-sided paper board, so that it is easy to stick to the upper and lower sides of the dryer.

(j) Hot plates are uneven, resulting in poor adhesion. As the hot plate used for a long time in the middle of the concave core, the pressure is not uniform, resulting in weak adhesion and degumming.

Solution: Replace the hot plate or re-level the hot plate.

(11) Tension is one of the important reasons for the formation of corrugated cardboard. The size and uniformity of the tension affect the forming and sizing of the cardboard, as well as the adhesive strength.

Solution: No matter whether it is the base paper roll on the bracket or the single-sided paperboard on the bridge, the tension should be adjusted at any time. To make the paper smoothly into the single-sided machine, press the paper by hand, the paper can drive the paper roll to rotate and the paper is continuous, this tension is more appropriate. When the base paper holder is working, the original paper roll is subject to a constant moment, so the tension (brake force) changes with the diameter of the paper roll. Therefore, the braking force should be adjusted at any time.

(12) The quality of the gluing roller affects the gluing, the surface quality of the gluing roller, the depth of the cable, and the size of the non-straightness has a great influence on the gluing. Bad glue, uneven, poor adhesion of cardboard, easy to open the plastic.

Solution: The operator should strengthen his sense of responsibility to prevent the rubber roller from scratching and bite with the corrugating roller. If the surface of the roller is damaged, the new roller must be replaced.

(13) The size of the gap between the pressure roller and the coating roller on the coating machine affects the amount of glue, resulting in poor adhesion and degumming. The gap is too large to be coated on the glue, not on the dryer. The clearance is too small, the corrugation is flat, the amount of glue is too large, the paste cannot be pasted, and the adhesion is not good.

Solution: The adjustment of the clearance should be determined according to the thickness of the single corrugated board passed on each roller. The gap between the press roller and the rubber-coated roller is generally smaller than the thickness of the single-faced corrugated board by 0.05 mm to 0.10 mm.