Overview of the application status and future deve

2022-08-06
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Overview of the use of gold and silver powder ink and analysis of its future development trend

printing materials printed with gold and silver powder ink are very popular with consumers, but there are a series of problems in the production, storage and use of these inks. This is a great challenge for silk printers. Before using metallic powder ink, you need to understand the differences between gold silver powder ink and traditional ink. First, we need to look at the composition of the printing ink for gold and silver vermicelli, what special needs it brings to the printing process, and understand what applications this ink is applicable to and what is not

what is gold silver ink

the main components of gold and silver vermicelli printing ink are: metal powder raw materials and liquid resin (i.e. ink binder). Ink binders act as binders for pigments and protect the ink film after drying

the metallic powders used in gold ink and silver ink are easily oxidized copper and aluminum powders, which will lose their metallic luster under the action of moisture, atmosphere, heat and some chemicals. For example, copper powder is easy to blacken when the binder is acidic or in the presence of trace sulfur, and it will slowly lose luster and blacken when it reacts with sulfur in the atmosphere after printing

its storage performance and printing performance are not good. Do not reuse the used ink. There is a certain proportion of zinc powder in the copper powder used for the gold ink. According to the different proportions, the gold color is reddish or fluorescent. It can also be made of aluminum powder and transparent yellow ink. Its gloss is not as good as that of the gold ink made of copper powder, but its gloss remains unchanged for a long time, and its chemical resistance and toxicity are also better

in the gold ink that looks golden, the pigment is made of a mixture of copper and zinc in different proportions. If the proportion of zinc is large (about 70% copper and 30% zinc), the gold color of the ink will appear light green, which is called richgold; If the proportion of copper is larger (90% copper, 10% zinc), the ink will show a light red color, which is usually called palegold. The above proportion is the two limits, between which you can get a color between the above two tones. These hues are slightly dyed with transparent orange colorant to obtain colors that match those specified in common color matching systems (such as Pantone color scale)

silver ink is made by dispersing aluminum powder in petroleum solvent and adding binder. There are two kinds of silver ink: one is that aluminum powder floats on the surface of the ink film, and its irregular reflection of light can produce the effect of silver glittering; Second, it is dispersed in the binder, and the appearance is silver white metal

the binders of gold ink and silver ink generally use resins with very low acid value and amine value to avoid affecting the gloss of the ink, such as ethyl cellulose, nitric acid fiber, polyvinyl acetate, polyamide resin, and some waxes are added to improve the suspension of the pigment. Gold ink and silver ink can also be prepared with solvent, but they are often ready for use because of their low viscosity. The polarity of the solvent does not need to be too large, otherwise the pigment is prone to precipitation due to excessive wetting. Xylene and isopropyl alcohol can be used as solvents for gold ink and silver ink. The gloss paste is used to improve the gloss of the ink. Dibutyl is used to increase the fluidity of the ink by reporting to the laboratory qualification department to go through the standard change procedures. The addition of dibutyl and No. 0 ink blending oil has an impact on the drying performance of the ink. Adding some dry oil can make the ink dry quickly. Pearlescent color is made by dispersing pearlescent pigment (or aluminum powder) in binder or transparent light color ink. The original color of the ink film and the multiple reflections produced by the color rendering of the metal powder can also be controlled by strain or displacement to form a pearl like luster effect, so it is called pearl color

the size of metallic pigment particles depends on their final use. For silk printing, the pigment particle size is usually 3~15 μ M. The specific requirements for pigment particle size in silk printing depend on the end use of the printed matter

the larger the particle size, the better the reflection performance of the ink film after printing, and the higher the gloss. Because when the pigment particles are relatively large, the surface of the pigment particles is relatively large, and more light will be reflected through it, the higher the gloss. However, too large particles of pigment from the oil hole cover and cam cover gasket to the transmission lip seal will make it difficult for the efficient transfer of ink in the printing process, because it requires a larger purpose. Fine metallic pigment particles are easier to transfer, unlike those too large particles that need to increase the target screen, but fine pigment particles sacrifice gloss

therefore, it is ideal to apply coarse pigment particles to low-grade printed matter, such as T-shirts; For high-end printing materials such as CD, the smallest pigment particle is the most ideal

however, in reality, gold silver powder inks containing pigments that just reach the ideal size do not exist - inks usually contain a mixture of pigment particles, most of which are within the target range. Although the level of pigment crushing processing technology has been improved, and the ability to separate particles according to size has also been improved, there is little difference in printing inks produced with coarse and fine pigment particles. This indicates that during the printing process, there are some pigment particles that cannot pass through the eyes and still stay on the plate surface

the size of pigment particles is too fine, which will sacrifice some gloss. However, the greater benefit is that it can obtain a fairly good surface coverage (for the same weight of pigment, the fine particles have a wider distribution area than the coarse particles). The challenge for silk printing manufacturers is to produce inks with pigments that are as fine as possible to achieve high coverage, good gloss, and close distribution

proportion of gold silver powder inks

metal pigment particles are usually coated with a layer of fatty acid during processing. During the printing process, this acid can help the pigment particles to suspend on the surface of the ink film. At the same time, the pigment particles are distributed in thin sheets, so as to obtain a smooth surface with reflective ability to light. Such an ink film is called a "layered ink film"

because the pigment is on the surface of the ink film, it is easy to fall off and wear. This problem is more obvious on the coarser pigment particles. If the size is smaller, the exposed surface area will be smaller, and it will be more firm. The only way to solve this problem is to use non layered gold silver ink. At this time, the pigment particles will precipitate to the bottom of the ink film, greatly improving their adhesion. However, because the particles are not arranged in a regular line at the bottom, the light must pass through the binder and enter the bottom before it can be reflected by the particle surface, sacrificing the gloss. Non layered gold silver ink is widely used in silver powder ink, but less in gold powder ink

printers will ask whether this kind of ink can be used outdoors. In some cases, it is possible. If the gold and silver pigments are specially treated, they can resist the gloss loss and oxidation defects exposed outdoors. When these pigments, which are similar to automobile coatings, are used for silk printing, the printed matter can not only resist ultraviolet radiation, but also withstand salt spray and other extreme climatic conditions. However, the ink using the above particles as pigments is much more expensive than the ink using ordinary metal pigments. It should also be noted that the ability of the treated gold pigment to resist extreme conditions is not as good as that of the treated silver pigment

the chemical characteristics of gold silver powder pigments determine that they cannot be directly added to the ink for sale as finished products. In most cases, metal powders are sold as part of the silk printing ink, and binders are added when used. This is because the metal pigment and transparent binder are mixed for a long time, which is prone to chemical reaction and emulsification. Under different conditions, when the metal pigment particles are mixed with the binder, the shelf life of the ink is also different, usually between several hours and months. Manufacturers of pigments and inks have been committed to solving the problem of limited ink shelf life. Now, some finished gold and silver vermicelli printing inks containing metal particles have come out, with a minimum shelf life of 6 months. It is expected that this kind of ink will become the dominant market in the next five years

use of gold silver powder inks

when printing with gold silver powder inks, the choice of substrate materials is very critical, because there are many fine pores on the surface, and the permeable substrate materials will absorb the transparent resin liquid. Especially when the ink viscosity is low, the resin will be absorbed, and the pigment particles will remain on the surface of the substrate materials. The resin composition is small, which will cause the silver powder to appear gray, while the gold powder will appear brown. If there is no other choice but to use absorbent substrate, it is best to first print a layer of ink (like the traditional transparent glazing oil) to seal the pores on the surface of the substrate, and then print gold and silver powder ink on it. A layer of varnish is printed on the metal ink film to resist the falling off and wear of particles in the ink. However, the more transparent varnish on the metal pigment particles, the weaker the reflection performance and gloss of the ink film

metallic pigments are easy to oxidize. Taking gold powder pigments as an example, their oxidation occurs on copper and zinc particles, resulting in the reduction of the gloss of the ink layer. In some cases, the ink even appears light green. Aluminum pigment in silver powder pigment is easy to turn gray and white after oxidation. Oxidation is one of the reasons why the color consistency of gold silver powder ink is difficult to achieve

another reason why it is difficult to guarantee the color consistency is the arrangement of pigments, especially the layered gold silver powder ink. The metal sheet floats on the surface of the ink film, forming many voids (the larger the size of the color particles, the larger the voids). After printing, the appearance of these small gaps makes the color of the substrate or the color of the lower ink appear visually through the surface color of the metal layer. For example, silver ink on a blue background will appear light blue; If yellow or green ink film is pre printed under the gold powder ink, the gold color of the ink will also be changed. Using white or light gray as the primary color can alleviate this problem. Silver powder pigment usually shows a dark color tone, while gold powder can not only show dark color tone, light color tone and various colors between them, but also can be used for handling. In fact, there are not many ways to get a series of "oxidation colors", which refers to the oxide reaction obtained under the allowed and controlled conditions of the pigment. The reaction results include the color tone of gold with lemon yellow or light orange red

gold powder pigments can also produce light colors such as green or purple, which are obtained by adding pigments of various colors to gold powder inks. However, these colors are more unstable. Compared with pure metal colors, they are very uncoordinated and easy to fade

light colored silver powders usually use transparent colorants so that they look like gold powder pigments. This method also solves the oxidation problem of gold powder. Such silver powder can be used for non layered gloss inks, but the color is not as clear as standard layered silver ink

in addition to traditional colors, most color matching systems point to a range of metallic inks. Silver powder metal pigment is used as the base color, and then colored with red, yellow or orange ink. The challenge of manufacturing this kind of ink is that some pigments such as red, orange and yellow used for color matching may react with metal pigments, thus destroying the printed text. Producers need to be extremely careful when mixing metal colors to avoid the above problems

use the toned gold silver powder ink, which increases the coverage area and can more accurately mix special colors. However, some ingredients added for color matching will reduce the luster of gold and silver pigments. When the customer turns the counter

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