(from http://www.cnzhixiang.com)
Corrugated cartons of poor waterproof and moisture-proof, has been criticized by the market defects.Especially in recent years, the market scale of cold chain packaging such as frozen meat, fruit and vegetable, medicine and so on is getting larger and larger. The corrugated packaging industry is in urgent need of fundamentally solving the problem that carton packaging is prone to collapse after dampening.
01. Heavy sizing box board
In the papermaking process of carton paper, heavy sizing is applied to the surface of carton paper to ensure that water droplets do not penetrate within 5 minutes on the surface.Starch paste is usually added in a large number of water-resistant additives, such as urea formaldehyde resin, melamine formaldehyde resin, polyvinyl butyral, etc.However, the cost of the water resistant agent is high, and in the production process of corrugated board easy to cause corrugated board cracking problems.
02. Coated paper
Dappling paper is the plastic particles coated on the surface of the paper composite material, the main characteristics are oil, water (relative), can be hot.However, due to the high cost, it is not conducive to the widespread promotion in the packaging industry.
03. Hydrophobic corrugated board
It refers to the process of coating low surface energy substances such as polylactic acid (PLA), polyolefin, polycarbonate, polyamide, polyester, fused paraffin and so on on the surface of paper board, to change the roughness and surface morphology of the material.Hydrophobic corrugated board in the water, the formation of a water drop on the lotus leaf, water into the water drop down, but not into the cardboard.The cost is very low, suitable for packing dry powdery articles, especially the powder which is easy to lump after absorbing water.It is also suitable for packing goods which often go in and out of the cold storage.After hydrophobic processing cardboard before dew evaporation will not significantly reduce the compressive strength, can effectively protect the goods.
04. Waterproof corrugated board
Also known as waterproof or waterproof corrugated board, its surface for a long time to contact with water almost impermeable, but can not be immersed in water, otherwise lose waterproof performance.Water-proof corrugated board commonly used curtain coating method, the melt of synthetic resin or paraffin mixture coated on the surface of corrugated board, forming a layer of resin film or wax film.If necessary, can also be double-sided coating.
Water-proof corrugated board is mainly used for packaging salt products, frozen food and fruit and vegetable products. Due to the soft paraffin layer on the surface of corrugated board, it is also suitable for packaging high finish furniture, piano, safe and precision machines that are easy to scratch.
05, water resistant corrugated board
After a long time in the water does not significantly reduce the strength of corrugated board is called water - resistant corrugated board.The production of water-resistant corrugated board has two kinds of equipment and technology, its processing principle and impregnation processing similar.Water resistant corrugated board can be used to measure its water resistance.The so-called water resistance is the corrugated board submerged in water (20±2℃ tap water)30mm, soak for 1h, and then test its rupture resistance and edge pressure strength, the residual strength should not be less than the standard strength (before immersion) 75%.
Waterproof corrugated cartons are used for carrying live fish, seafood and a class of commodities with a very high water content.However, such cartons are difficult to recycle and the eu has restricted their use.
06. Corrugated cartons with smooth surface
Finishing packaging products after printing a common process, the surface of the product through coating, can make the printed matter to enhance the resistance to water, sun, friction and pollution resistance and other properties, but also improve the surface brightness of the product, make the grade of the product greatly improved.
Corrugated box glazing process is usually surface paper pre-printed glazing, then mount synthetic corrugated board, die cutting processing into cartons.Also can be directly on the surface of corrugated board glazing, but waterproof effect is not good, may damage the carton compression.
07. Corrugated cartons covered with film
Mulch is the polypropylene and other plastic film covering the surface of the printing, and the use of adhesive after heating, pressure to make it glued together the process.Mulching process is divided into precoated mulching and coated mulching.Color box covered with film after the surface of bright, friction resistance, a certain waterproof effect, folding box is not easy to crack.But product recycling is difficult, the United States and Europe and other countries have restricted the use.
Aluminum coated kraft paper board
Toyo steel co., LTD has developed an 0.02 mm to 0.05 mm thick of pure iron foil, the antirust processing, zinc plating, nickel or tin with kraft paper, polyethylene film extrusion composite composite board, used to make the cartons, not only waterproof, moistureproof, still can shield the electromagnetic wave, antistatic, especially suitable for aquatic products, fruit and vegetable, electronic instrument, semiconductor devices and mechanical and electronic products packaging.Aluminized polyvinyl chloride film and kraft paper composite after the production of cartons, the same waterproof, moisture-proof functions.
09. Corrugated paste is added to waterproof carton
In the process of corrugated board production, in the starch binder to add an appropriate amount of polymer (also known as cross-linking agent or bridging agent), polymer will replace the starch molecules in the hydroxyl, so that the corrugated line has a better waterproof and moisture-proof effect.When the carton into the cold inventory or damp environment, can prevent the corrugated paste line moisture absorption emulsification caused by carton collapse.
As for often advertised this kind of product can improve the cardboard bonding effect, improve the bonding stability and other aspects are somewhat exaggerated.
The air vents of the cartons are moisture-proof
For the products with heat in the packaging of beer, a certain amount of hot steam formed in the box after packing may be absorbed by the carton, and the compressive strength will decline.For these cases, the usual practice is to mark the side of the carton in the appropriate position, respectively with two diameter of 18mm vent hole.