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Basic knowledge of aluminum paste

Nov 29, 2021

To understand aluminum and silver paste, we must start with his industry classification. Aluminum-silver paste belongs to chemical industry->fine chemicals->inorganic pigments->metal pigments, and metal pigments are divided into two categories, namely copper pigments and aluminum pigments. Copper pigment is what we usually call copper gold powder/gold paste, and another aluminum pigment is our protagonist this time-aluminum silver paste. Before introducing aluminum silver paste, we must first have a basic understanding, that is, what is the difference between pigments and dyes? Dyes are colored organic compounds, which are generally soluble in water or organic matter, or some insoluble dyes are changed into a dispersed state by chemical means to promote dissolution. The pigment is different. It is an insoluble colored compound, generally insoluble in water, oil and solvent, but can be uniformly dispersed in the solvent. Generally speaking, the pigment exists in the solvent in the state of particles, and the dye exists in the solvent in the state of molecules. In the huge family of pigments, there is one of the most "shining and dazzling" members-aluminum silver paste. It is called aluminum-silver paste because it is mainly composed of aluminum flakes and petroleum solvent, which is in the form of a paste. After processing through a special treatment process, the surface is smooth and flat, showing a silver metallic luster, so people call it aluminum silver paste.
Basic knowledge of aluminum paste(图1)
At the same time, it also has many aliases, such as silver paste, silver powder paste, aluminum powder paste, flash paste, etc. According to the arrangement and distribution of aluminum in the aluminum-silver paste, it is mainly divided into floating aluminum-silver paste and non-floating aluminum-silver paste: floating aluminum-silver paste refers to the distribution of aluminum pigments on the entire coating, and the arrangement is relatively neat and capable It exhibits excellent metal effect, achieves the effect of imitation electroplating, high brightness, and strong corrosion resistance, but its adhesion is relatively weak and it is not easy to color. Non-floating aluminum-silver paste means that the aluminum pigments are distributed in the middle and lower parts of the coating, and the arrangement is messy. It will show the metallic effect of "different colors at different angles", with strong adhesion and easy coloring. But relatively speaking, the metallic feel is weaker than floating silver. According to the construction process of aluminum silver paste, it is mainly divided into fine silver, imitation electroplating, and flash silver. Fine silver: In the construction process, the aluminum sheet is crushed by a steel ball, and then ball milled until the diameter of the aluminum sheet is broken (aluminum is originally a piece of piece), and then smoothed to open its ductility to make it Higher hiding power. Generally, fine silver is characterized by its poor metallic feel and high hiding power. The particle size is generally below 12μ. Imitation electroplating: Through the grinding of the ball mill little by little, on the premise of ensuring that the diameter of its sheet is not broken, and the structure of the aluminum itself is not damaged, the diameter of the sheet is opened to grind the metal feeling. Generally, the characteristic of imitation plating is that it has a strong sense of metal, but the production is relatively time-consuming. The particle size is generally below 12μ. Flash silver: The process is much simpler than the imitation electroplating and fine silver process, and the effect it presents is flashing. The particle size is generally divided into fine flash, medium flash and coarse flash, and the particle size is between 15μ and 64μ. After we roughly understand a basic concept of aluminum silver paste, we need to further understand its related properties. Which mainly involves metallic feeling, hiding power, adhesion, stability, dispersion and other characteristics of different industries. Metallic: the appearance of aluminum silver paste; Covering power: the arrangement of the aluminum sheet is tight, whether it can cover the substrate with the least amount of addition; Adhesion: Whether the silver paste can be well wrapped in the resin system without losing silver; Stability: Whether there is no reaction in the aluminum-silver paste coating system to ensure a long service life; Dispersibility: Whether the aluminum silver paste can dilute well without sedimentation and agglomeration. Of course, the above are just some common attributes. For each industry, there are different test indicators. For example, the glass paint must be resistant to alcohol, and the printing must be resistant to washing.