In high temperature environments during summer, the storage stability of water-based silver paint (including aluminum powder) is particularly prominent, especially in long-term transportation scenarios such as export shipping. Aluminum powder is prone to oxidation, blackening, and swelling due to high temperature and humidity. Tech-8892 passivator can effectively improve the above problems and extend the storage period of aluminum containing slurries

1. The principle of aluminum powder passivator

      Aluminum powder passivator forms a dense layer of aluminum oxide film (Al2O3) on the surface of aluminum powder through chemical or electrochemical methods. This film can block the contact between aluminum and the external environment (such as water and oxygen), prevent further oxidation of aluminum powder or reaction with water to generate aluminum hydroxide and hydrogen gas (reaction equation: 2Al+6H2O → 2Al (OH) 3 ↓+3H2 ↑), avoid problems such as blackening and swelling of aluminum powder, and help disperse oily aluminum powder into aqueous systems to improve the corrosion resistance and stability of aluminum powder


2. Advantages of Tech-8892
     Tech-8892 is particularly noteworthy for its inorganic acidic or alkaline passivators (such as solutions containing sodium fluorosilicate and aluminum nitrate), while Tech-8892 belongs to weakly acidic organic copolymer passivators. Based on organic acid derivative technology, the reaction is mild and does not damage the substrate, and it also has the function of dispersing and stabilizing aluminum powder

Advantages and Features
● Form a transparent/light colored film that does not affect the appearance of the workpiece
● Excellent salt spray resistance
● Strong adhesion of the coating
● Improve dispersibility

Applicable scenarios
In water-based metal paint and water-based plastic paint
Aluminum alloy, stainless steel (especially high silicon die cast aluminum), workpieces that require subsequent coating or maintenance of their original color

Environmental friendliness
Does not contain harmful substances such as chromium and phosphorus, complies with RoHS standards, and the wastewater is easy to treat

Precautions for use
Front end cleaning: It is recommended to first clean the oily aluminum powder in a 1:1 ratio using solvents such as ethanol/BCS to remove impurities on the surface of the aluminum powder, and then filter it.
Passivation treatment: Mix Tech-8892 with 20% aluminum powder and passivate at room temperature for 24 hours before use


3. Actual effect
① Tech-8892 Aluminum Silver Paste Passivation Test
Step 1: We added DB solvent to the oily aluminum powder and mixed it evenly. Then, we added TAG Tech-8892 aluminum powder passivator and passivated it for 48 hours, comparing it with the blank


Step 2: Add 50g of deionized water directly to the aluminum silver paste and mix evenly. The blank sample is severely clumped and cannot be used. The aluminum silver paste with Tech-8892 added has good fluidity.

② Tech-8892 Coating Testing
We compared the blank sample with the Tech-8892 coating test in terms of metallic feel, silver powder alignment effect, and thermal storage stability by testing in water-based self drying and water-based baking paint

■ Aqueous acrylic lotion system. The basic formula (complete set of Tiger additives) is as follows :

Stability test : Water based silver powder paint undergoes 14 days of thermal storage at 50 ℃

Tech-8892 does not blacken its surface and has good storage stability in water-based acrylic lotion system

■ Water based baking paint system

Spray water-based silver paint on ABS board after the same heat storage.
The display of Tech-8892 has excellent metallic feel, with well arranged silver powder and no black spots on the surface of the board

4. Summary
The test experiment shows that after passivating oily aluminum powder, Tech-8892 exhibits excellent stability in both water-based self drying and water-based baking paint, significantly improving the metallic feel (silver powder arrangement), improving black spot problems, and no swelling of the can