What moisture proofing treatments are needed for wooden blackboard shipped by sea?

Wooden blackboard is mostly made of solid wood or MDF (medium-density fiberboard). Wood itself easily absorbs moisture. During long-distance ocean voyages, the large temperature differences between day and night in containers can easily cause "container rain," leading to problems such as mold growth, warping, and blistering of the blackboard paint. This is a common risk in foreign trade exports. A complete moisture-proofing treatment needs to be implemented at multiple stages, from raw materials, finished product surface, packaging to container loading.

First, controlling the moisture content of raw materials is fundamental to moisture prevention. Before leaving the factory, the moisture content of the wood needs to be tested and controlled within the export standard range of 8%-12%. When the moisture content exceeds the standard, changes in the marine environment will cause the wood to shrink and expand, leading to warping and cracking of the wooden frame. During the production stage, the wood can be dried and sprayed with anti-mold agents to inhibit the adhesion of mold spores and reduce the probability of mold growth from the source.

Second, the finished product surface needs sealing treatment. The wooden blackboard frame can be sprayed with varnish or a sealing primer to form a protective film on the wood surface, reducing moisture penetration. The writing surface of blackboards also needs proper paint protection to prevent moisture from seeping into the board through the gaps. For blackboards made of MDF (medium-density fiberboard), the cross-sections of the board should be sealed with paint, as the larger gaps in the cross-sections are the most susceptible to moisture absorption.

Packaging moisture protection is crucial. Each blackboard should be wrapped with moisture-proof paper or PE waterproof film. Silica gel desiccant and anti-mold sheets should be placed inside the cardboard box to absorb any residual moisture. Thickened waterproof corrugated cardboard boxes should be used for outer packaging, and the entire pallet should be wrapped with stretch film for sealing. Heat-treated wooden pallets conforming to ISPM15 standards should be used preferentially. A moisture-proof mat should be placed at the bottom of the pallet to separate the goods from the container floor and prevent condensation from seeping in.

The container loading process is equally important. Before loading, the container must be inspected to ensure there are no leaks or standing water. Container desiccant bars should be hung on the inner walls of the container to absorb moisture from the air inside. Leave gaps between the goods and the container walls; do not place them tightly against the walls to prevent condensation from dripping onto the products. Avoid loading on rainy days to prevent external moisture from entering the container. Comprehensive moisture-proofing treatment can effectively reduce cargo damage during sea freight, decrease returns and claims, and ensure the safe arrival of wooden blackboards in overseas markets.