Sharing of technical ideas on ink printing drying in the printing and packaging industry

               Using source substitution to manage VOCs has been a hot topic in the industry, and ink printing has also received much attention. Ink and wash printing is a traditional and new thing. Speaking of its tradition, it develops on the edge of the industry, never far away from us, just around us. In the face of no environmental pressure, it has always maintained a mysterious veil, and everyone is unwilling to spend time and cost trying to break through it. In developed regions in Europe and the United States, it is basically printed with ink, and has long been used in domestic flexographic printing, digital, and industrial printing; Speaking of its freshness, at least it has not been widely used in the flexible packaging industry, especially in the application of color ink (except white ink). Because it is not widely used, it appears fresh, but it is also the ultimate solution for the development of the entire printing and packaging industry. At present, the core issue that everyone is debating is whether the printing and drying efficiency can meet the requirements, environmental protection and customer requirements.

               When it comes to ink printing, problems such as slow speed, high energy consumption, the need for revision, and the treatment of alcohol emissions have plagued various enterprises, making many enterprises hesitant to adopt ink printing, making it difficult to choose between them.

To further solve the drying problem of ink and wash printing, let's first understand the existing traditional ink and wash drying methods:

① Large air volume, fresh air mode. Although it can help improve speed and drying, it can also deform some substrates, resulting in inaccurate overprinting, and greatly increase energy consumption costs, increasing the burden on enterprises; In accordance with the national GB38507-2020 standard and the direct emission of environmental protection shall not exceed 10mg/m 3 You can imagine how much air volume is required.

② Extended oven. With a large air volume, this is equivalent to increasing the heating time of the substrate in the oven, which will have a certain effect. However, after the oven is saturated with humidity, the printing machine must slow down, otherwise it will produce anti adhesion. The feasibility of adding a small amount of water (below 20%) and a high proportion of alcohol is strong, but the assistance for ink printing with excessive water in the diluent is limited.

③ Increase the temperature. Raising the temperature is equivalent to increasing the air unsaturation. The less saturated the air, the easier it is to remove moisture from the oven. However, the temperature resistance of the printing carrier is limited, and only an appropriate increase in temperature can be achieved, and energy consumption will increase.

④ Change to a lighter version and increase the alcohol ratio. Through research, the light version can greatly improve the drying efficiency, but the light version is not durable and has insufficient coverage. The evaporation point of alcohol in alcohol ink is similar to that of water, and it also requires increased air flow and temperature. The speed cannot be compared to that of solvent ink.

So, how can "ink drying" achieve low emissions, low energy consumption, and high efficiency printing?

1. Energy conservation. Affected by national power restrictions and electricity price adjustments, energy-saving is a must for ink drying, and can also increase the market competitiveness of enterprises. For example, Jinchuang ink drying system can achieve an energy efficiency ratio of up to 1:3 (i.e., 1 degree of electricity generates 3 degrees of electricity) during drying, and the investment can be recovered within one year.

2. Improved printing speed. In the case of limited air volume and temperature, it is necessary to consider handling the humidity of the air supply. The lower the humidity, the better. The low humidity drying wind quickly removes the moisture from the ink, and the substrate is quickly dried, increasing the original efficiency by over 30% to meet customer needs.

3. Low temperature drying for better results. Under the same air volume conditions, the low-temperature drying hot air generated by the strong dehumidification ability fully ensures the drying effect, does not damage the film structure and generate ink application problems such as false drying and anti adhesion, and continues to stabilize printing.

4. Low or no exhaust. Combining the characteristics of air reduction and thickening with the all-new air drying mode, it circulates 70% to 80% of the air and heat in the printing machine oven and ink drying system, that is, the air and heat cycle, and the water and alcohol are discharged. Currently, Jinchuang Company, a well-known domestic enterprise, is at the forefront, and the air exhaust for ink printing is only within 30%.

5. Water ink printing with no or less revision. Using the plate material of the original printing machine or changing only one color white plate (full plate) to complete the printing upgrade of oil to water with minimal cost, while taking into account the drying of solvent ink printing, resulting in lower air volume and temperature requirements during ink printing.

              Therefore, in the process of ink printing, printing and packaging factories should dare to try. If they have not used ink printing before, they can consider the idea of using white ink before color ink, and gradually use and transform equipment. A factory considering ink printing must consider ink drying in the order of humidity, air volume, and temperature. It is not allowed to use the previous thinking to use high energy consumption and high exhaust air for ink drying. Alcohol should be collected and recycled as much as possible, with less exhaust air and less exhaust air, and without exhaust air. Finally, a good ink dryer should be selected to save energy and speed up, improve product quality, and meet environmental emission requirements.

              The above content is my sincere insights. Due to limited knowledge, technical exchanges are welcome. In order to overcome the difficulties of industry development, we all strive for progress and development together.

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