Cardboard is the main raw material for the production of corrugated boxes, cartons and other products. How its performance directly or indirectly affects the internal quality and use effect of the product. For corrugated boxes, carton and other packaging products, it has wear resistance, waterproof and moisture resistance, and has high strength and good air tightness, which is the basic quality requirement for the use characteristics of cardboard. However, the ordinary paperboard produced by the paper mill often does not have good wear resistance, water resistance and moisture resistance. The strength and airtightness of the cardboard vary according to the quality grade of the cardboard. Therefore, from the perspective of improving the performance of corrugated boxes and cartons, it is necessary to process the surface of the cardboard by some necessary technological processes in order to fundamentally improve the performance and appearance quality of the cardboard. 1. Polishing process on the surface of cardboard. Polishing is a common process for post-printing processing of packaged products. After coating on the surface of the product, the printed products can be enhanced in water resistance, light resistance, friction resistance and pollution resistance. It can improve the surface brightness of the product and greatly improve the grade of the product. Varnishes have a variety of structures. They are useful for oily varnishes varnished by printing presses, water-based and oily varnishes varnished by varnishers, as well as solvent-based varnishes and UV varnishes. The characteristics of glazing coatings are different, and the technological effects of product surface processing are also different. It is also a bright paint, because of different material characteristics and formulas, its gloss effect and wear resistance are also different. When coated with matte paint, the surface of the printed product has almost no glossiness, but it has a certain artistic sense. Some products have matt paint, and the process effect is no less than that of bright paint. Regardless of whether it is bright or matt paint, the coating must have good wear resistance to protect the surface of the printed product. Process characteristics of oily glazing. When applying oily varnish on a printing machine, the thickness and drying of the glaze coating are limited by the structure of the machine. The gloss and wear resistance of the printed surface are not as good as those of solvent-based or water-based varnishes on the glazing machine. Therefore, this kind of glazing is generally only suitable for ordinary products with small batches and low quality requirements. Technical characteristics of solvent glazing. The surface gloss and abrasion resistance of products polished with solvents are relatively high, but because the thinner is an organic solvent. Such as toluene, as the solvent evaporates, the cost of glazing paint is also large. Solvent glazing coatings have poor physical and chemical resistance, and the coatings are prone to yellowing, and solvents with strong odors not only easily pollute the environment, but also have a certain impact on production safety. Therefore, the production site must pay attention to exhaust emissions, and the machine uses electric heating pipes For drying, attention should be paid to keep the cardboard conveyed smoothly, to prevent the cardboard conveying from being skewed and blocking the drying tunnel to touch the electric heating tube, causing fire safety accidents. Technical characteristics of waterborne glazing. The water-based glazing paint has the advantages of colorless, odorless, non-toxic, non-irritating, fast drying of the coating, wear resistance, high temperature resistance, no yellowing, no color change, and high transparency and gloss, so this process is more suitable It is used for surface finishing of food packaging. However, the solvent of the water-based glazing oil is water, and the printed matter is easily deformed after being glazed. Its abrasion resistance is second only to solvent glazing coatings. If the outer layer of cardboard is packed with PVC plastic film, it is easy to stick to the glazing film layer and graphic ink color of the printed product due to the stickiness of the surface of the PVC plastic film. Therefore, the outer packaging material is PVC plastic film, water-based paint should not be used for varnishing cardboard, but solvent-based wear-resistant varnish should be used for varnishing. Technical characteristics of UV coating. UV glazing is to apply UV glazing oil to the surface of the printed product to form a high gloss film on the surface. After the glazed film layer is irradiated with ultraviolet light, photopolymerization and photocrosslinking reactions occur inside the coating, and then quickly solidify and dry, so that there will be no adhesion quality failure, which is conducive to ensuring the rapid operation of subsequent processes. The UV glazed coating has the advantages of wear resistance, chemical resistance, chemical resistance, and good stability. Since the UV varnish does not have the problem of solvent evaporation, unlike the pollution problem caused by the solvent-based glazing process to the environment, and its relatively small amount, its production cost is much lower than that of the laminating process. Therefore, it is an ideal process to replace plastic coating and solvent-based glazing. However, in production, the problem that should be noted is that UV paint will have a certain stimulating effect on human skin, and direct UV light will also cause certain damage to the human body. The coating will produce ozone after drying by UV irradiation. The production site should have good Ventilation. 2. The requirements for glazing coatings for paper packaging products In terms of product use and processing characteristics, glazing coatings must meet the basic requirements of safety, hygiene and environmental protection. Therefore, the flexibility, leveling and wear resistance of glazing oils It should have good resistance, acid and alkali resistance and adaptability, and the varnish must have high transparency and discoloration resistance. The surface film layer should have good toughness to protect the surface of the printed product and enhance the product. The waterproof, moisture-proof, dirt-proof and wear-resistant properties of the packaging. Paper surface calendering process Calendering is a deep processing process based on glazing. The production process is roughly: the printed product is first polished with the glazing machine, and after the varnish layer of the printed product is dried, it is hot pressed with a calender to make the glazed film layer form a smoother and high-gloss mirror effect. This is a quality effect that cannot be achieved by the general glazing process, so this production process is more used for surface finishing of packaging products such as preprinted corrugated boxes and cartons. Traditional calender coatings use organic solvents such as toluene and cyclohexanone as diluents. Not only is it easy to pollute the environment and endanger the health of the human body, but it is also easy to cause pollution to the product, leaving hidden dangers to the product packaging, so it is not suitable for food and pharmaceutical packaging. From the perspective of packaging safety, environmentally friendly water-based calender oil that is non-toxic, odorless, and pollution-free should be used. The waxing process on the surface of the cardboard. The waxing process on the surface of the cardboard. The production process and equipment are relatively simple, and the operation is very easy to master. The process is to use a waxing machine to evenly apply the wax liquid melted by heating to the cardboard or printed matter. On the surface, when the paraffin coating on the paper is cooled, it solidifies to form a thin, very smooth waxy film layer, which makes the paper have better waterproof, moisture-proof, mildew-proof, dirt-proof, rust-proof, Oil resistance and abrasion resistance, so this process is generally used for surface processing of food packaging, paper packaging and other products that are not resistant to moisture. The spraying process on the surface of the cardboard uses a laminating machine to spray a layer of polyethylene or polypropylene with a thickness of 0.01mm to 0.07mm on the surface of the cardboard to improve the airtightness and tensile strength of the cardboard. The moisture resistance, water resistance, oil resistance and dirt resistance of the cardboard are greatly improved. In recent years, with the continuous prosperity of the market economy, the demand for coated cardboards for liquid beverages, solid frozen foods and other products has increased, and the technology for coating has become more and more mature. According to the use characteristics of the product, the coating processing of the cardboard can be single-sided or double-sided. For double-sided coated paperboard, printing quality control is 4 points important. If the process is not properly controlled, the quality problem of overprinting is prone to occur. That is to say. The ink is printed on the PE film that has no absorption properties, and it is easy to stick to the back of the printed matter. Therefore, the printing of double-sided coated cardboard with a lithographic printing machine without a drying device should be printed with abrasion-resistant, strong adhesion, and non-absorbent ink to ensure the printing quality of the product. Laminating process on cardboard surface Laminating is a common finishing process for preprinted carton facial paper, carton, handbags, covers and other products. After the printed product passes through the film, it can achieve the properties of waterproof, antifouling, anti-fading, heat resistance, light resistance, friction resistance, etc. At the same time, it can enhance the gloss, aesthetics, piercing strength and tensile strength of the product, and improve the use of the product. Lifespan and packaging quality. The general process of laminating is: After the product is printed, the plastic film is combined with the surface of the printed matter into a whole structure with a laminating machine to form a paper and plastic printed matter. The coating process is divided into coating film and pre-coating film; there are also differences between hot coating and cold coating. There are different types of adhesives for coating, including water-based coating adhesives and solvent-based coating adhesives. The solvent coating adhesive has high brightness, but there is a problem of environmental pollution, and the solvent of water and coating adhesive is water, which has little pollution to the product and the environment. Therefore, it is widely used in the finishing process of the surface of food packaging. Because the laminated products need to be sorted and processed during recycling, the regeneration process is relatively complicated and the production cost is high. Some packaging products are being replaced by calendering or UV glazing processes. Third, the production process of functional corrugated cardboard Functional corrugated cardboard is a new type of packaging material, which is different from ordinary corrugated cardboard: the processing of raw paper or carton through a special technical process, which expands the use of carton, at the same time Also improve and enhance the quality of the carton. Increase the added value of products to meet the individual needs of product packaging. From the perspective of logistics characteristics, product characteristics and market requirements, functional corrugated cardboard is an important production technology to improve the quality of product packaging and effectively protect the product. The main performance of waterproof corrugated cardboard is that the surface of the cardboard is impermeable, but it cannot be immersed in water, otherwise it will start to penetrate through the inner layer and break. The main processing technology is: the curtain coating method is about to melt The synthetic resin or paraffin mixture flows down from the hopper 13 into a film and is coated on the corrugated cardboard running horizontally. After the surface of the cardboard is coated with a layer of resin film or wax film. That is, it has good water resistance and abrasion resistance. This corrugated cardboard is mainly used for packaging pickled products, fruit and vegetable products and refrigerated food. Because the corrugated cardboard surface has a soft paraffin layer, so. It is also suitable for high-finish furniture, high-end goods or industrial instruments whose packaging is easily scratched. The manufacturing process of hydrophobic corrugated board is also called water-repellent corrugated board. This kind of corrugated board has high water repellency. When it comes into contact with wet objects or is exposed to rain or splashing water, the surface of the waterproof cardboard has certain water-repellent properties , So that the water droplets will not penetrate the cardboard fibers. The processing technology is as follows: first, the cardboard is coated and processed, such as coating varnish, paraffin, silicone and other hydrophobic substances. Before applying varnish, it is best to coat the starch slurry layer on the surface of the paperboard once, and then apply varnish after it is dried to form a film. Silicone not only has good water repellency, but also has flame retardant, corrosion resistance, temperature resistance and other properties. Paraffin coating has higher smoothness, better wear resistance and water repellency. Adding appropriate amount of water resistance additives to the hydrophobic coating, such as polyvinyl butyral, melamine formaldehyde resin, etc., can improve the water resistance of the coating, and can better improve the water repellency of the corrugated cardboard surface. Therefore, the hydrophobic corrugated cardboard box is suitable for packaging those powdery substances that are easy to agglomerate after absorbing moisture, as well as refrigerated food, which can better protect the product. The manufacturing process of water-resistant corrugated board is different from that of waterproof and hydrophobic corrugated board. When it is immersed in water for a long time, its strength will not drop significantly. This good performance and its processing Process characteristics. This production process can use a wax-immersed automatic paper feeder to continuously feed corrugated cardboard into a paraffin-wax dipping tank at about 90 ° C. After continuous dipping for 6 seconds to 12 seconds. The corrugated cardboard can be properly controlled according to the quantity and the number of layers of corrugated cardboard. It is appropriate to use wax liquid to soak the corrugated cardboard. After the corrugated cardboard is saturated with wax liquid, it can be taken out from the wax tank and the excess wax liquid is removed, and then slowly moved through a hot drying room at about 100 ° C to make the wax liquid evenly penetrate into the cardboard fiber. At the same time, the local excess wax is leveled. The wax-dipped corrugated cardboard after the completion of the hot baking is solidified under normal temperature conditions or forced cooling. After the paraffin soak processing, the corrugated cardboard has better water resistance. This kind of carton is especially suitable for live seafood, frozen fruit and other products with high moisture content. There is also a water-resistant processing method for reinforcing paperboard: adding a water-resistant reinforcing agent directly to the papermaking slurry. The water resistance of the cardboard is improved, and at the same time, it can better prevent the powder and lint from appearing on the surface of the cardboard. Preparation process of fresh-keeping corrugated cardboard The fresh-keeping corrugated cardboard adopts special processing technology to make the carton pack fresh fruits and vegetables. It can reduce the water loss of the contents, inhibit the growth of bacteria, and absorb the bad gas in the box. Make fruit and vegetable products get better preservation effect. The general production methods of fresh-keeping corrugated cardboard are: plastic-plastic type, composite type, foamed type and mixed type. The plastic-plastic type is to sandwich the plastic film soaked with antibacterial agent and fresh-keeping agent in the corrugated cardboard, and then Preservatives are coated on the corrugated cardboard box. This corrugated cardboard box can not only effectively prevent the evaporation of water, but also can regulate and control the temperature and keep the products in the box fresh. The compound type is to compound the aluminized cling film with the inner surface of the corrugated cardboard box, so that the box body has the function of absorbing ethylene gas, preventing the evaporation of moisture, and at the same time reflecting the radiant heat and preventing the temperature rise in the box. Then play a role in keeping fresh. The foam type is a combination of foam plastic and corrugated cardboard, and its freshness preservation effect is more superior than the previous two methods. It is better in suppressing evaporation of water, controlling heat resistance and air tightness. The manufacturing process of the mixed corrugated cardboard is: adding porous ethylene gas absorbing powder into the cardboard or coating the base paper with special ceramic powder that can emit infrared rays of a certain wavelength. Cartons made from this kind of cardboard can activate some molecules in fruits and vegetables. Enhance the function of resisting microbial erosion and improve the technological effect of fresh-keeping packaging. In summary, the surface treatment of cardboard is an important technical means to improve the added value and quality of commodities, improve the packaging grade and quality of products, effectively prevent damage to packaging and commodities, and enhance the market competitiveness of commodities. and so. Correctly understanding the production process and method of cardboard surface technical treatment, and selecting the appropriate packaging process according to the characteristics of the goods will undoubtedly have a better promotion effect on improving the promotion of the goods and improving the economic benefits of the enterprise.