"Whitening" is the phenomenon that when the ink is cold, the water vapor in the air becomes water droplets mixed into the ink, causing gelatinization, turbidity and precipitation. The main reasons for the phenomenon of "whitening" are as follows:
① The heat provided by drying is insufficient, and it is too far away from the drying channel.
② The rapid evaporation of solvent causes a sharp drop in the surface temperature of the ink film, even below the dew point, resulting in moisture condensation into water and mixing into the ink.
③ The printing speed is too slow, so that it takes too long from the completion of printing to entering the drying Road crossing, and so on. "Whitening" will significantly reduce the luster, transparency and adhesion of the product.
The solution is:
① Increase the printing speed and make the printing roller close to the drying channel.
② Some slow drying solvents can be used to slow down the drying time. However, when a large number of slow drying solvents are used, problems such as residual odor and adhesion of printed matter are easy to occur. Therefore, it must be used according to the minimum requirement, and must not be added too much.
③ During the drying process of printing, sufficient heat is provided for solvent evaporation.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service.
The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries.
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