In recent years, the market scale of cold chain packaging such as frozen meat, fruits and vegetables, and medicines has become larger and larger. Corrugated boxes have poor waterproof and moisture-proof performance, which has been criticized by the market. So, is there a good way to solve the problem that the cartons are easy to collapse after being damp?
Corrugated box waterproof and moisture-proof solutions mainly include the following points:
Add water resizing additives
1. During the papermaking process of cardboard paper, re-sizing the surface of the cardboard paper can ensure that water droplets will not penetrate to the surface within 5 minutes. Usually, a large number of waterproof additives are added to the starch paste, such as urea-formaldehyde resin, melamine-formaldehyde resin, polyvinyl butyral, etc. However, the cost of waterproofing agent is relatively high, and it is easy to cause problems such as peeling of corrugated cardboard during the production process of corrugated cardboard.
Hydrophobic carton
2. Also known as waterproof corrugated cardboard, it refers to coating low surface energy substances on the surface of the cardboard, such as polylactic acid (PLA), polyolefin, polycarbonate, polyamide, polyester, molten paraffin, etc., to change the roughness of the material surface degree and surface morphology. When the hydrophobic corrugated cardboard is soaked with water, it forms a water drop state on the lotus leaf, and the water turns into water droplets and slides down without penetrating the inside of the cardboard. Hydrophobic corrugated cardboard has low cost and is suitable for packaging dry powder items, especially powders that are easy to agglomerate after absorbing water. The cardboard after hydrophobic treatment will not significantly reduce the compressive strength before the dew evaporates, thus effectively protecting the goods.
3. Waterproof (covered) corrugated cardboard
Also known as waterproof or water-retaining corrugated cardboard, its surface is almost impermeable for a long time, but it cannot be immersed in water, otherwise it will lose its waterproof performance. Waterproof corrugated cardboard is usually used in the curtain coating method, and the molten synthetic resin or paraffin mixture is coated on the surface of the corrugated cardboard to form a layer of resin film or wax film. Double-sided coating is also possible if necessary.
Waterproof corrugated paperboard is mainly used for packaging pickled products, frozen food and fruit and vegetable products. Due to the soft paraffin layer on the surface of corrugated cardboard, it is also suitable for packaging high-quality furniture, pianos, safes and precision machinery that are easily scratched.
