Method, use technology and dispersion technology of aluminum silver paste

1. Dispersion of aluminum silver paste

   Effect coatings containing aluminum powder pigments should achieve excellent gloss, scintillation, brightness, hiding power, coloring power, flop effect, vividness, floatability, etc., must be well dispersed, but should be dispersed Note the following tips and suggestions:

   Tip: Aluminum scales are easy to bend and break. In the process of paint production, if they are subjected to high-speed agitation or other continuous and intense processing, the geometry is easily destroyed, resulting in coarse particles, dark color, reduced hiding power and metal migration. Therefore, high shear dispersion means should not be used.

   Recommendation: It is recommended to use a pre-dispersion method: first select the appropriate solvent or a mixture of several solvents. The solvent is added to the aluminum slip at a ratio of aluminum slip to solvent of 1:1 or 1:2, and slowly stirred until homogeneous (about 10-20 min), and a wetting agent or dispersant is added to the system.

2, resin system

   Many commonly used coating bases such as oil varnish bases, acrylates, alkyds, epoxies, polyurethanes and aqueous bases are available in both floating and non-floating aluminum silver paste pigments. In general, any coating binder or solvent is suitable as long as it is compatible with the solvent of the aluminum silver paste and does not cause chemical damage to the aluminum silver paste. It is worth noting that aluminum is an amphoteric metal and the acid value of the paint should be controlled below 7.

Flux selection

   The choice of flux is primarily determined by the paint defined by the formulation. Non-floating aluminum pastes can be widely used as polar fluxes, such as aliphatic or aromatic hydrocarbons, esters (such as butyl acetate), ketones (such as methyl ethyl ketone, methyl isobutyl ketone), and alcohols (such as ethanol). The floating aluminum paste can only use non-polar flux, and it is preferably a high surface tension aliphatic or aromatic flux, especially petroleum flux oil, diphenyl, toluene and high flash point naphtha, because they Can promote excellent floating. Moisture will react with aluminum to form a hydrogen-producing effect. Therefore, the water content in the coating should be strictly controlled to be less than 0.15%. It is recommended to use the bayer dehydrating agent to remove excess water from the coating flux or dilution. Flux-containing agents are not suitable for use in any aluminum silver paste pigment.

Drier selection

   When a coating system containing aluminum silver paste pigment needs to be added with a metal drier, the non-floating aluminum silver paste can only be applied if it does not react with the fatty acid on the surface of the green scale. Cobalt, zirconium and manganese driers are recommended.

Aluminum silver paste selection

   The particle size and particle size distribution of aluminum silver paste pigments have a crucial influence on color, hiding power, flop effect and gloss. Therefore, particle size distribution is an important parameter that can not be ignored when selecting aluminum silver paste. Products with a stable particle size and particle size distribution should be selected. Particle size and particle size distribution are not the only technical parameters for selecting aluminum silver paste. Even if the particle size and particle size distribution are the same, different surface treatments or aluminum flake shapes will result in hue, hue or metallicity, whiteness, and flop effect. The difference in optical effects, so the final need for aluminum silver paste pigments, but also need to make a small sample board and sample reference comparison analysis.

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