Metal pigment copper gold powder copper gold powder preparation gold ink product introduction copper gold powder product gold ink use method
Gold ink is printed with gold-gloss ink, which is made of copper alloy powder as pigment. A printing gold ink prepared from a special binder and gold powder. The copper gold powder can be used as the gold ink of four colors of cyan, cyan, red and purple copper gold powder; according to the type, there are offset gold ink, letterpress gold ink, gravure gold ink, silk screen gold ink. The production types are gold ink made by the ink production factory and gold ink made by the printing factory with gold oil and gold powder.
Several issues to be aware of when printing gold ink
Gold can give people a gorgeous and noble feeling, and the golden color of the golden light is also unable to express the spectral color. Therefore, gold ink printing is widely used in packaging and printing technology, and plays a better role in improving the image of goods. However, since the main raw material of gold ink is brass powder, it is chemically active metal, which is prone to discoloration. Therefore, we should pay attention to the following situations when printing gold ink:
1 Gold ink is easy to contact with air and water vapor and chemical reaction causes discoloration. Therefore, it is necessary to do a good job of keeping copper gold powder in a safe place, so that it is not exposed to the air, and the unused copper powder should be tightly covered;
2 Because the chemical nature of copper powder is not stable enough, if it is in contact with acid, alkali, carbon and sulfide, different degrees of chemical changes will occur. The metallic luster is reduced and the gold ink is blackened. Moreover, gold ink should be avoided for printing large-scale domestic coated paper and offset paper, because the paper produced by the acid papermaking process is acidic, and the gold ink not only discolors after printing, but also loses luster;
3 Auxiliary materials for metal inks should not be used, and acid-containing auxiliary materials should not be used, but neutral substances should be used;
4 The use of gold ink should be mastered with the principle of printing with the tone, that is, the amount of one-time adjustment should be suitable for continuous printing for about 3 hours, so as to avoid excessive adjustment of the gold powder in the grease for too long, contact with air to oxidize and deteriorate and lose golden luster. ;
5 The speed of gold ink printing should not be too fast, because the frictional heat of the ink roller is increased accordingly, so that the gold ink is easily oxidized and blackened. Therefore, the speed of the printing gold should be controlled at about 3000 sheets/h;
6 offset printing gold fountain solution, should use acid or gum-like fountain solution, so as to avoid the reaction of acid fountain solution and copper gold powder, so that the ink color of the printed product becomes dark and tarnished;
7 When printing gold, the rubber roller should be adjusted. The position of each rubber roller should be adjusted accurately to avoid the occurrence of ink accumulation during the printing process due to poor ink transfer, so that the copper powder stays on the rubber roller for a long time, causing the gold ink to oxidize. Discoloration
8 The semi-finished products of printing gold ink should not be stacked too much, otherwise the heat released by the gold ink during the drying process of the paper can not be emitted as soon as possible, and the gold ink will also be oxidized and discolored;
9 When the machine ink fountain and the ink roller are cleaned with kerosene and gasoline, the organic solvent retained on the surface has not completely evaporated, that is, the gold ink is printed immediately, so that the gold ink reacts with the solvent to cause discoloration;
10 If you print gold on the ground color, you should pay attention to the appropriate addition of dry oil in the background color, so as to avoid overprinting the gold ink because the bottom ink is not dry, it will affect the luster color of the gold ink.
Gold ink printing precautions
(1) The nature of the paper: The nature of the paper will have a great influence on the printing quality of the gold ink. The higher the smoothness of the paper, the better the tightness, the better the printed metal effect; on the contrary, the paper with a porous surface and coarse texture On the printing, the effect will be poor. In addition, the pH value of the paper surface is preferably greater than 5.5. Otherwise, when the printed product is stacked and stored, the sulfate contained in the paper will cause the gold powder to change color and black, and even cause the gold powder to be corroded and disappear.
(2) Gold ink printing graphic: The graphic of gold ink printing layout should not be too thin, otherwise it will easily cause paste, and its reflection effect will also be worse.
(3) Abrasion resistance: The wear resistance of the gold ink layer after printing is an important indicator for measuring the quality of gold ink printing. At present, there are two measures to solve the abrasion resistance of gold ink: one is to use gold oil with a slightly higher viscosity of gold, and the other is to use bright light glazing after printing.
(4) Discoloration of gold ink: After the gold ink printing product is left for a period of time, the copper gold powder will be invaded by sulfur, oxygen, moisture, etc. in the air, so that the gloss of the imprinted surface becomes dark or even black, which affects the product quality. This is what we usually call the problem of discoloration of gold ink, which should be paid attention to during the storage of printed products.
(5) Overprinting of gold ink and other color inks: Gold ink should be printed on dark solids as much as possible. For example, gold is printed on red, blue and black, and the effect is good, especially in purple, black and dark blue. The effect is better when printing gold ink.