Features and skills of printing ink for the hottes

2022-08-19
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Metal packaging materials printing ink use characteristics and skills

metal is an important packaging material, which plays a very important role in packaging. Metal printing is different from ordinary paper and plastic printing. It has its own printability characteristics that the original balance bridge of the universal experimental machine loses balance and outputs a voltage signal proportional to the deformation. It has special requirements on the ink used

1. The reasonable selection of metal printing coating, glazing oil

coating and glazing oil is the key to the quality of metal printing products. Reasonable selection of coatings and varnishes is the premise to ensure that metal printing products have good firmness, color, whiteness, gloss and processing suitability. According to different uses, metal printing coatings can be divided into primer, white paint, glazing oil, inner wall paint, edge seam paint and so on. The side seam paint that does not meet the current fast-paced market competition can be divided into inner side seam paint and outer side seam paint. After drying, the inner side seam paint is required to meet the requirements of food hygiene

2. metal printing ink

metal printing ink is a special ink printed on tinplate and other metal sheets, which is mainly composed of pigments, binders, fillers and auxiliary agents

in addition to the printability of general offset printing inks, metal printing inks should also have the following characteristics:

(1) impact resistance and strong adhesion. In the process of post press processing, metal materials such as tinplate need to go through canning processes such as cutting, bending impact, seams, etc., so the ink layer should have sufficient adhesion, so that the printed tinplate can withstand the stamping of the mold, and has excellent machining performance (including flexibility, surface hardness, impact strength, etc.). At the same time, it is required that the ink layer has good lipophilicity, so that it can be well combined with the glazing oil, so as to ensure a certain degree of adhesion between the sheet and the ink layer and the glazing oil

(2) firm and hard. In the process of making green plastic packaging materials for cans, it is not only necessary to be hygienic and environmental friendly, but also inevitable that the printed tinplate after polishing will collide with each other, and the cut tinplate is very sharp, which is easy to damage the patterns on the metal surface and make the ink layer fall off, so the ink layer is required to be firm and hard

(3) heat resistance. In the drying process, the printing piece must go through the heating and drying process at a certain temperature and time. Therefore, pigments and binders with strong heat resistance should be selected to prevent the ink from yellowing after heating

(4) solvent resistance. In order to make the appearance of metal prints beautiful, improve the hardness, and prevent damage caused by friction, it needs polishing. Glazing oil contains a lot of strong solvents, which requires that the ink layer after drying does not change color, expand or shrink

(5) light resistance. When metal containers are exposed to sunlight and light, the color of the pattern shall not change

(6) cooking resistance. Some metal cans need to be boiled for sterilization or heated before drinking, so it is required that the ink layer will not change color, stain, bubble and gloss after being exposed to steam

since the surface of metal substrate cannot be penetrated, it is easy to produce point increase. Compared with paper printing ink, metal printing offset lithography should use high viscosity ink. The metal surface is a non absorbent surface, and too much wetting water on the layout is easy to produce ink emulsification. Therefore, the water and ink balance on the layout should be achieved by controlling the water film thickness and ink amount on the layout

in metal printing, in order to improve the adaptability of post press processing and make the surface of the printed piece have a certain gloss, polish (post press coating) should be carried out before the printing ink is completely dry to form a uniform and smooth film to avoid color bleeding. At the same time, the metal printing ink should have a certain hardness and toughness, and its properties cannot be changed when the material with excellent activity needs reheating. The base color coating and glazing oil should have good adhesion

reprinted from: China Hong Kong silk screen printing

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