Silk screen freezing point change gravure freezing point process

Freezing ink, also known as snowflake ink, is a UV ink that can produce a fine and uniform texture on the surface of the ink after two curing, which can protect and decorate the surface of the product, so it is widely used in the packaging and printing industry. Especially in the domestic cigarette packaging printing industry, nearly 20% of cigarette packaging products will be decorated with freezing ink, basically every cigarette packaging printing company will use freezing ink, it is only a matter of how much use, so freezing ink is an essential surface decoration material. The traditional freezing ink printing process of ink manufacturers is usually achieved by screen printing after offset printing or gravure printing, but this process has drawbacks such as slow printing speed and large ink consumption, so our company explored and launched a single concave freezing process, that is, the use of sheet gravure printing machine to print freezing ink. In this paper, the author will analyze the drawbacks of screen printing freezing process according to the curing principle of freezing ink.

Resin is one of the important components of ink, which is divided into UV resin and ordinary resin, the former needs to be cured by specific wavelengths of UV light irradiation, the latter can be cured under specific temperature (or heat) conditions. In the freezing ink, these two different characteristics of the resin exist at the same time, which puts forward new requirements for the curing of the ink: first through a specific wavelength UV lamp, so that the ink surface cure and form lines, and then through three high-power UV lamps, so that the ink surface and the inner layer cure at the same time, so as to obtain a stable printing effect. Due to the particularity of the printing effect of freezing ink, it is necessary to make the thickness of the ink layer meet certain requirements when printing, so that the ink can achieve the effect of surface curing and inner layer not curing when the first UV light irradiation, and this physical property will lead to the formation of small and uniform texture on the surface of the ink layer; When the textured ink is irradiated by a second UV light, the ink is completely cured, forming a stable, dry surface finishing effect. From the curing principle of freezing ink, it is necessary to print a certain thickness of the ink layer in order to obtain a more uniform texture effect. In order to obtain the printing effect of relatively thick ink layer, the selection of automatic screen printing machine is a more ideal way.

Screen printing ink layer control mainly depends on the choice of mesh mesh, such as the common mesh mesh number of 150 mesh, 200 mesh, 250 mesh, 300 mesh, 320 mesh and 350 mesh. Using screen printing process to print freezing ink, according to the different printing effects, generally choose the mesh number of 250 ~ 320 screen. Although screen printing can ensure the thickness of the ink layer very well, the freezing process of screen printing also has certain drawbacks. The most prominent is the slow printing speed, based on the characteristics of the screen plate back and forth movement, the printing speed of the screen printing machine can only be controlled at about 2500 sheets/hour. And the ink consumption is large, according to the normal printing of cigarette pack boxes to calculate, if the number of cigarette pack boxes is 15 (paper size is 510mm×731mm), then the consumption of freezing ink is about 26 kg/million.