Cardboard surface treatment process (I)

Cardboard is the main raw material for the production of corrugated boxes, cartons, and other products. How does its performance directly or indirectly affect the intrinsic quality and performance of products? For corrugated boxes, cartons and other packaging products, it has wear-resistant, waterproof and moisture-proof properties, and has high strength and good airtightness. It is the basic quality requirement for the use of cardboard. However, ordinary paperboards produced by paper mills often do not have good abrasion resistance, water resistance, and moisture resistance. The strength and airtightness of cardboard vary depending on the quality level of the board. Therefore, in order to improve the performance of corrugated boxes and cartons, it is necessary to carry out some necessary processing and processing of the surface of the cardboard in order to fundamentally improve the performance and appearance quality of the cardboard.

Cardboard surface glazing process

Glossing is a commonly used process for post-printing of packaging products. After the surface of the product is coated with glaze, the printed product can enhance the properties of water resistance, light resistance, friction resistance, and stain resistance, as well as increase the surface brightness of the product. The grade of the product has been greatly improved. Gloss coating has a variety of structures, such as oil-based coating varnish for printing presses, water-based and oil-based varnish for varnishing, solvent-based varnish, and UV varnish. The characteristics of glazing coatings are different, and the process effects of product surface processing are also somewhat different. The same is the bright type of paint, because of the material properties, different formulations, the gloss effect, wear resistance, etc. are also different. With matte coating, the surface of the printed product has almost no glossiness, but it has a certain sense of art. Some products have a matte coating and the process effect is no less than that of a bright coating. Whether it is light or matt coating, the coating must have good abrasion resistance in order to protect the surface of the print.

Oily coating process

With the oiling varnish of the printing machine, the gloss and abrasion resistance of the surface of the printing product are limited by the structure of the coating due to the thickness and drying of the coating coating, and the effect of the solvent-based or water-based coating on the optical machine is not as above. Therefore, this kind of glazing is generally only suitable for ordinary products with small batches and low quality requirements.

Solvent polishing process

The products with solvent coating have high surface gloss and abrasion resistance, but because the diluent is an organic solvent such as toluene, the consumption of the coating coating is also large with the volatilization of the solvent. The solvent coating coating has poor resistance to physical properties and the coating tends to be yellowish. Moreover, the odor-rich solvent not only tends to pollute the environment, but also has a certain impact on the production safety. Therefore, the production site must pay attention to exhaust emissions, and the machine uses an electric heating tube. Drying, we must pay attention to maintaining the smooth transport of cardboard, cardboard to prevent skewing and blocking the drying of the road so as to touch the electric heating pipe, causing fire accidents.

Waterborne glazing process

The waterborne coating has a colorless, odorless, non-toxic, non-irritating, coating drying speed, wear resistance, high temperature resistance, no yellowing, no discoloration, and has good transparency and high gloss, so the process is more suitable In the food packaging surface finishing processing. However, the solvent of water-based coating oil is water, and the printed product is prone to deformation after it is glazing. Its abrasion resistance is second only to the solvent glazing coating. If the outer layer of the cardboard is packaged with PVC plastic film, the surface of the PVC plastic film is likely to be sticky, and the glazing film and the graphic ink color of the printing material are easily damaged. Therefore, the outer packaging material is a PVC plastic film. The cardboard coating should not use water-based paint, but should use a solvent-based wear-resistant glazing coating for glazing. This is the company's experience in a quality accident.

UV coating process

UV coating is the use of UV coating on the surface of the printed material, the surface of the film to form a high gloss. After the glazing film is irradiated with ultraviolet light, photopolymerization reaction and photocrosslinking reaction take place inside the coating layer, thereby rapidly solidifying and drying, so that no blocking quality failure occurs, and it is favorable for ensuring fast operation of subsequent processes. UV coating has the advantages of wear resistance, chemical resistance and chemical resistance, and good stability. Since UV varnish has no problem of solvent evaporation, unlike the solvent-based varnishing process, the environmental pollution caused by the solvent coating process is relatively small, and its production cost is far lower than that of the coating process. Therefore, it is an ideal process to replace plastic coating and solvent-based coating. However, in production, the problem that should be paid attention to is that the UV coating will have a certain stimulatory effect on the human skin. UV light will also cause certain damage to the human body. The coating will produce ozone after being dried by UV irradiation. The production site should have good Ventilation exhaust.