ere are some reasons make cardboard get wet:

1. Weather
Plum rain season, wet weather, the humidity in the air can reach 80% or even higher.  And cardboard moisture is generally 6-8% when just done, when they directly meet the air, it will attract humidity in the air and become soft  
Solution: We can't control the weather, but we can fix the storage environment:
1) When building the warehouse, the ground should be paved with a layer of asphalt, and then covered with a layer of plastic film (a thicker one), and then poured cement to prevent the infiltration of moisture underground in rainy season and wet weather.

2) Purchase dehumidifiers to absorb moisture in the air.

3) Try to isolate the humid air outside.

2. Cardboard material
Corrugated paper plays a physical role in cardboard, such as compression resistance, buffering and anti-stamping, but its own material is not good, strong water absorption, once gets damp and soft, the cardboard collapses when your fingers press it.

Solution: It is suggested to replace corrugated paper with a better sizing degree. At present, the sizing degree of each major base paper manufacturer is slightly different. Reasonable selection can reduce or reduce part of the phenomenon of softening.

3. Manufacturing technique
Paperboard needs preheating in production to achieve the effect of drying. Then press the corrugated, paste, glue, then finished paperboard leave the production line for air drying. Preheating can easily achieve the effect of drying during this process. The change of paste formula and waterproof additives can reduce the phenomenon of softening.

Solution: increasing borax content and adding waterproof agent can reduce the softening probability.

4. Storage environment

Finished cardboard should be placed in a ventilated environment for air permeability, cardboard boxes can not be directly placed on the ground, and need to use a pad (tray, plywood) to carry them up. Pay attention to the gap between each other in storage, in order to facilitate ventilation and heat dissipation.

Solution: it is recommended to use wooden pads, which can absorb moisture from the ground and are the same size as cardboard boxes; Keep the storage environment ventilated.

5. Transportation environment

Transportation is a necessary process, there are commonly open truck and van, the latter than the former can keep cardboard dry, avoid and reduce back to soft.

Solution: It is suggested to use van transportation, which is also commonly used by major suppliers.

6. Carton processing technology

 The number of carton production process will cause cardboard damage, such as line pressing wheel, pre-printing wheel, printing plate domain, die-cutting area, etc., easy to cause cardboard to lose rigidity, soft phenomenon.

 Solution: strictly control the production process in production, reduce artificial damage, avoid repeated preloading, preloading overload, etc.