Precautions and solutions for nano printing embossed paper materials

In the previous text (Printing on embossed paper labels, can nanoprinting technology be feasible?), the author analyzed some advantages of nanoprinting technology from the aspects of printing principles and printing effect comparison, and preliminarily explored some possible problems that nanoprinting technology may encounter when printing embossed paper materials. In this article, the author will delve into it with everyone.
01
The influence of ink film and curing degree on ink firmness
Nanoink is pre coated on a heated conveyor belt, dried, and then transferred to a textured paper on a rough surface. During this process, whether the ink can adhere to the material surface and fully penetrate into the grooves and ridges of the material, forming a bonding force, is the key to testing the firmness of the ink.
The pre lamination and drying of nanoink should be moderate and adjustable. Ink cannot form a film and become a solid after drying, otherwise the ink layer will lose its viscosity and cannot bond with the same material after transfer. Therefore, the film and drying degree of nano ink, that is, the viscosity of the ink layer after film bonding, is one of the key factors in solving the problem of ink firmness.
02
Formula adjustment of ink
Adjust the ink formula based on the characteristics of embossed paper. For example, increasing the resin content (such as using acrylic resin with strong affinity for paper), improving the cohesion and adhesion of the ink, adjusting the distribution of nano ink pigments, allowing the ink to better fill the embossed depressions, and increasing the contact area. In addition, adding additives enhances ink adhesion. You can try adding adhesion promoters (such as silane coupling agents), which can form a "bridge" between ink and paper, strengthen molecular bonding, or add wear-resistant agents (such as nano silica particles) to enhance the friction resistance of the ink layer and reduce ink drop during transportation and use.
03
Printing process adjustment
1. Accurately control ink transfer parameters
Repeatedly test to find the appropriate ink transfer pressure, temperature, and speed for embossed paper. The pressure needs to be balanced, allowing the conjunctival ink to fully adhere to the surface of the embossed paper while not excessively squeezing and damaging the paper or ink film. The temperature and speed should be well coordinated, and the film temperature of the conveyor belt (blanket) and the transfer temperature when in contact with the printing material should be controlled to ensure the stability and adhesion of the ink after transfer.

2. Optimize the drying treatment of ink surface
The nano printing machine is equipped with a post press polishing device, so after ink transfer, it can increase the overall material drying treatment (such as infrared drying, hot air drying), allowing the ink to further solidify, film, and dry on the surface of the embossed paper, improving the firmness of the overall ink layer.
04
Material pretreatment
Embossed paper materials may damage the fiber structure of the material during the embossing process, resulting in paper wool and paper debris on the surface or deep inside the embossing. This defect can affect the firmness of the ink or cause white spots on the surface of the ink. Therefore, before printing, cleaning equipment (such as ion air cleaning, electrostatic precipitator) should be used to remove dust, oil, and other impurities on the surface or inside of the embossed paper. It is also possible to perform appropriate corona treatment on the surface of the paper to increase surface tension and activity, making the ink easier to wet and spread, and enhancing the initial adhesion of the ink.
05
Quality Verification and Prevention
1. Sample testing and simulation verification
Before formal production, a small amount of printed samples are tested for ink firmness through simulated transportation (vibration, friction testing) and usage scenarios (manual touch, environmental temperature and humidity changes). The adhesive tape peeling method can be used (referring to national standards such as GB/T 7707-2008 "gravure decoration printed products", etc.) to observe the ink peeling situation, or a wear tester can be used to evaluate the friction resistance of the printed samples.
2. Establish quality standards and processes
Develop quality standards for nano printing of embossed paper wine labels, clarify ink firmness indicators (such as ink residue rate ≥ 90% after tape peeling), and add a sampling process for ink firmness in the production process to promptly identify problems and adjust the process.
Overall, it is technically possible to use nanoprinting technology to print embossed paper wine labels, but the ink firmness needs to be focused on. By customizing ink, optimizing processes, material pretreatment, and conducting rigorous testing and verification, the risk of ink loss can be effectively reduced to ensure printing quality. Therefore, it is recommended to conduct small-scale trial production and verification first, and then gradually expand to large-scale production.