Reasons and solutions for low board strength

In the automated production of cardboard, almost all manufacturers want high strength and stiffness. However, it is often counterproductive. Many manufacturers produce cardboard that is soft and has low strength. Customers are not satisfied and even fail to meet national standards. So what are the causes of these problems? This article analyzes these reasons and proposes solutions to the problems for the majority of cardboard manufacturers.
One, cardboard moisture is too high. The solution is to reduce the moisture in the board. There are many factors that cause high water content in cardboard, and the situation is also more complicated. The specific analysis and solutions are as follows:
1. The glue used in the cardboard production line is much more watery. Solution: Reduce the moisture in the glue.
2. A large amount of glue. There are two reasons for the coating: one is that the gap between the applicators is large. The solution is to adjust the slit of the applicator roll appropriately. The second is that the viscosity of the glue is too large when the slit is not changed. The actual amount of glue will be relatively increased; the viscosity of the glue is small and the actual amount of glue is significantly smaller. When the viscosity is too small, the amount of rubber to be coated is very small, and even the glue cannot be applied. Solution: Adjust the size of the slit of the rubber roller to ensure the proper amount of glue. In addition, when the glue is used, the viscosity of the retaining glue is basically the same. When the viscosity of the glue varies greatly, the slit size should be adjusted at any time to ensure that the amount of glue applied is moderate.
3. The boot speed is too fast. The cardboard has a short residence time in the drying tunnel and the drying time is not enough. Solution, according to the situation to control a reasonable boot speed.
4. Steam pressure is low. Solution: Increase the vapor pressure; if you can not increase the vapor pressure, you can only reduce the boot speed.
5. The cardboard itself has high water content. The paper in the same paper mill is not constant, and the moisture in the same batch of incoming paper is high or low. Solution: Control paper moisture, paper moisture is too high, should not be used.
6. The air is high in humidity and the moisture does not go out. Solution: Only reduce the boot speed appropriately, extend the drying time, and reduce the moisture in the paper.
7. The width of the cardboard is too large, and it is difficult to disperse moisture when producing large-width paperboard. Solution: There is no good solution, and only the boot speed can be properly reduced.
Second, corrugated forming or forming temperature is not good. Solution: Take appropriate measures to improve the forming temperature of the corrugation and ensure that the corrugated form is in good condition.
Third, the paper's own strength is not high. Solution: Use high-strength paper.
Fourth, the adhesive strength is not much. Solution: Identify the cause of poor adhesion and ensure firm adhesion.
Fifth, the film hardness is not enough. At present, the vast majority of manufacturers use pure corn starch, plus a certain amount of caustic soda, borax, their own plastic. For their own use, the adhesive itself is not high in hardness and has little effect on improving the strength of the cardboard. The starch produced by different producing areas and different manufacturers has almost no difference in the film strength of the glue prepared with the same formulation; but if the same kind of starch is different, the adhesive strength of the prepared glue is different. In order to increase the strength of the film, the use of simple corn starch adhesive strength is not enough, but also can not produce high strength cardboard. Solution: The special reinforcing powder for cardboard production lines should be used. At present, Hefei Xuegong Adhesive Technology Co., Ltd. has successfully launched a special reinforcing powder for paperboard production line. The effect is good and the cost does not increase. Some also introduced water-reinforced additives, but the cost is high.
In the automatic production process of cardboard, the reasons for the softness and low strength of the cardboard are various, and the solution must also vary from one case to another. When a problem arises, it is first necessary to carefully analyze the problem, identify the cause, and successfully solve the problem. It should not be simply for some reason.
Through the above analysis, we can see that as long as we understand what factors affect the strength of the board, in the production process, control these factors in the best condition, we can produce high-strength cardboard to meet the needs of the market.