Silver Rocket Aluminum Paste, produced by Zhangqiu Metallic Pigment Co., Ltd., is developed by a professional aluminum pigment manufacturer with 39 years of experience in aluminum pigment research and production.

As an important metallic pigment used in coatings and paints, aluminum paste creates unique metallic effects that cannot be achieved by conventional pigments. However, achieving the best performance depends greatly on proper formulation and application techniques.

The following practical tips help coating manufacturers obtain stable dispersion, strong metallic effects, and optimal coating performance when using aluminum paste.

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1. Ensure Proper Dispersion in the Coating System

To achieve the desired metallic effect, aluminum paste must be evenly dispersed in the coating system.

Aluminum flakes are delicate and can easily bend or break during processing. Excessive high-speed or high-shear mixing may damage the flake structure, which can lead to:

• darker color appearance

• reduced hiding power

• coarse particles

• metallic floating problems

Recommended Method: Pre-Dispersion

A pre-dispersion process is recommended to maintain flake integrity.

Suggested steps:

1. Select a suitable solvent or mixed solvent.

2. Mix aluminum paste with solvent at a ratio of 1:1 or 1:2.

3. Slowly stir the mixture for 10–20 minutes until uniform.

4. Add the dispersed aluminum paste into the coating system.

In industrial production, aluminum paste is often soaked in solvent for about 30 minutes before gentle stirring to achieve optimal dispersion.

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2. Choose Compatible Solvents

The choice of solvent depends on the coating formulation.

For non-leafing aluminum paste, both polar and non-polar solvents can be used, such as:

• aliphatic hydrocarbons

• aromatic hydrocarbons

• esters (e.g., butyl acetate)

• ketones (e.g., MEK, MIBK)

• alcohols (e.g., ethanol)

Selecting compatible solvents helps maintain dispersion stability and metallic brightness.

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3. Avoid Chlorinated Solvents

Chlorinated solvents should not be used with aluminum paste pigments.

These solvents may release hydrochloric acid (HCl), which can chemically react with aluminum flakes and damage the pigment structure.

This reaction may result in:

• pigment degradation

• coating defects

• reduced metallic performance

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4. Ensure Compatibility with Coating Resins

Many coating resins are compatible with non-leafing aluminum paste, including:

• acrylic resins

• alkyd resins

• epoxy resins

• solvent-based varnish systems

• water-based coating systems

The key requirement is that the solvent system of the coating must be compatible with the solvent carrier of the aluminum paste and must not chemically attack aluminum flakes.

Important Note

Aluminum is a reactive metal, therefore the acid value of the coating formulation should be controlled below 7 to avoid corrosion reactions.

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5. Select Suitable Drying Catalysts

When metallic driers are required in aluminum-containing coating systems, only those that do not react with the fatty acids on aluminum flakes should be used.

Recommended driers include:

• cobalt driers

• zirconium driers

• manganese driers

These catalysts help accelerate drying without damaging aluminum pigment surfaces.

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6. Recommended Aluminum Paste Dosage

The dosage of aluminum paste varies depending on coating types and desired metallic effects.

Typical dosage ranges include:

Proper dosage ensures both visual metallic effect and coating performance.

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7. Achieving Proper Aluminum Flake Orientation

The orientation of aluminum flakes in the coating film strongly affects the final metallic appearance.

When aluminum flakes align parallel to the coating surface, the coating produces the best metallic effect.

However, poor orientation can cause:

• hazy appearance

• diffuse reflection

• reduced metallic brightness

Factors Affecting Flake Orientation

Several factors influence aluminum flake alignment:

• coating formulation

• solvent evaporation speed

• application conditions

• solid content of the coating

Generally, low-solid coatings tend to produce better optical metallic effects than high-solid systems.

During drying, solvent evaporation causes shrinkage in the wet film, pushing aluminum flakes into a horizontal orientation, which enhances metallic reflection.

Additives such as:

• CAB (cellulose acetate butyrate)

• wax dispersions

• certain surfactants

may also help stabilize flake orientation and improve coating appearance.

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Conclusion

Proper handling and formulation techniques are essential to maximize the performance of aluminum paste in metallic coatings. By controlling dispersion, solvent compatibility, catalyst selection, and aluminum flake orientation, coating manufacturers can achieve superior metallic effects and stable coating performance.

With 39 years of aluminum pigment manufacturing experience, Silver Rocket continues to provide reliable aluminum paste solutions for industries such as automotive coatings, industrial paints, packaging coatings, and printing inks worldwide.