We know that the fiber used in carton base paper is a hydrophilic material with strong water absorption. In humid weather such as plum rain season, when the relative humidity in the air is too high, the carton will directly contact with the air and absorb the moisture in the air, resulting in the production of corrugated cartons and the whole cardboard is also soft. So how to improve the moistureproof performance of corrugated boxes? Here is a brief introduction.
1. It is recommended to use original paper with better waterproof and moisture-proof effect, especially tile paper with pits. To check the waterproof effect of the base paper, the surface water absorption of the base paper can be tested by the Cobb instrument. Generally, when the surface water absorption is below 50g/m2 (60S), the waterproof and moisture-proof effect is good. Generally, in order to improve the surface waterproof property of base paper, the paper mill needs to increase the proportion of waterproof additives in the surface sizing starch paste.
2. During the production and processing of cartons, the moisture in the cartons shall be removed as much as possible. The base paper warehouse shall be isolated from the outside as far as possible to avoid humidity in the air inside the warehouse. When making paste, increase the content of powder and reduce the amount of glue, which can reduce the moisture of the carton. In addition, increasing the proportion of borax will also improve the feel of corrugated cardboard. Reduce the amount of cardboard piled up on the paper overpass, and slow down the speed, especially fully dehumidify the corrugated cardboard after stacking.
3. Storage environment: after offline cardboard, the steam that has not dispersed should be removed to avoid condensation caused by temperature difference. The environment for storing cardboard or cardboard boxes should be ventilated. The cardboard boxes should not be placed on the ground, and should be supported by base plates (pallets, plywood). Pay attention to the mutual clearance during storage to facilitate ventilation and heat dissipation.
4. In the process of product delivery, some use open top trucks for transportation, and some use van type trucks. Generally, the latter can protect the dryness of paperboard better than the former, and avoid and reduce the softening.
5. The corrugated cardboard shall enter the next process as soon as possible after it is taken off the cardboard assembly line. The longer the cycle is, the easier the cardboard will absorb the moisture in the air and soften. The residence time of the carton in the production and processing process shall be shortened as far as possible to avoid softening due to too long exposure to humid air. The workshop should also be properly isolated from the outdoor to avoid direct blowing of water vapor into the workshop.
The problem of carton softening is actually the influence of moisture. In the process of base paper storage, corrugated board processing, carton processing, storage and transportation, it is necessary to prevent the carton from absorbing water, so as to better improve the moisture resistance of corrugated carton.
