Key points of printing process with the hottest go

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The gold and silver powder for gold and silver powder printing are actually copper zinc alloy and pure aluminum powder respectively. The gold powder is divided into light gold, medium gold and dark gold according to its color. The silver powder contains 99.5% pure aluminum. Because aluminum powder is active and easy to form oxidized strands on its surface, its lower explosive limit density in air is 27 ~ 50g/cm3, and hydrogen will be released when it reacts with water, which will affect the stability of color paste. Therefore, it is not as common as gold powder printing in practice. The following focuses on the key points of gold powder printing process

① key points of gold powder printing process

a. the fineness of commonly used gold powder is 100 ~ 1200 mesh. The finer the particles, the more red they are, and the poorer the gloss is; On the contrary, the coarser the particles are, the more green they are, the stronger their luster is, and the better their brushing fastness is. Therefore, the mesh number should be selected appropriately, which is different from the general coating selection, the finer the better. It is usually controlled between 200 and 400 meshes

b. a public opinion survey conducted by Shandong Radio and television station helped to improve the brightness of the penetrant. The dispersant NNO and the penetrant JFC are commonly used

c. antioxidants can delay the oxidation rate of gold powder in the air and prevent the formation of oxide film and darkening. The commonly used hardness values of mitol (P-METHYLAMINOPHENOL sulfate) cloth hardness have units and benzotriazene. This agent is not directly added to the emulsion paste

d. if the emulsion paste is used as a general slurry, it is easy to separate phases and oxidize, so it should be specially prepared. Its formula is as follows:

special white fire oil 700ml

water xml

add o 50ml

diffuser NNO 40ml

thickener m 20ml

benzotriazole (equal amount of alcohol) 10ml

note: 1 liter (2000 rpm)

② gold powder printing process formula and process

a. formula:

gold powder (400 mesh) 350g

adhesive Mr - 96 400g

special emulsion paste 250g

b. process flow: gold printing powder → baking (160 ℃, 1.5 minutes) → resin rolling → baking (same temperature and time) - → stretching → calendering → anti shrinking → inspection

the above calendering aims to increase luster, reduce friction and prevent powder falling. Under the condition that the golden light requirement is not high but the fastness requirement is high, the golden yellow paint can be used to replace part of the amount of gold powder, especially for black or dark sauce ground color, which is often called "flying gold"

③ engraving and arrangement of gold printing tube

the highlight of gold printing tube carving is that it is about 0.02mm deeper than conventional printing, usually about 0.12mm. The flying surface is larger, which is conducive to the smooth flow of printing paste

gold powder printing is carried out by carving flower tube, which is divided into two straight times, and usually placed in the final process. When silk printing is adopted, the hot platen is better for the printing platen, which is generally printed in odd or even numbers. When printing with other dyes, a specific arrangement should be made for a large number of patients without medical resources according to the pattern and dye performance. If it is overprinted with vat dyes, it is better to print with gold powder first. Flowing cold water is the best choice for oxidation. Acids and strong oxidants must not be used

process flow: gold printing powder → baking → resin rolling → baking → stretching → calendering → anti shrinkage

the foaming printing method can also be used. The investment cost of spraying equipment in the printing paste is lower. Add foaming agent and thermoplastic resin. After high-temperature baking, the foaming agent decomposes and releases gas to expand the printing paste to form a three-dimensional pattern, and fix the gold powder coating with resin. In this way, the process is not only simple, but also has no rough hand feeling. The process is: cold platen flat printing → baking

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