Molecular Sieve For Powder Coatings Sealants & Adhesives
Moisture Challenges in Coatings, Sealants & Adhesives
Strong adsorbents, such as molecular sieve, are useful for efficiently regulating humidity and moisture in liquids and gasses. It’s crucial to remember that adhesives, sealants, and coatings might suffer from moisture. Water vapor from fillers or surrounding air may combine with these products during manufacture. Contaminated gases, such as carbon dioxide, can also cause problems with moisture, which may lead to scorching and degradation.
Role of Molecular Sieve as Active Desiccants
Molecular sieve are used as active desiccants in powder coatings, sealants, and adhesives to solve these issues and guarantee moisture free final products.
How They Are Incorporated in Formulations
Molecular sieve are not directly used in this procedure. Rather, during product handling and mixing, oil and active chemicals are combined with powdered molecular sieve to minimize the surrounding humidity.
Types
Adsorbents 3A, 4A, and 5A that are powdered efficiently and non reactively remove moisture from sealants, adhesives, and coatings. Generally, their usage involves 1% to 5% of the product’s weight, contingent on the water content of polyol and further additions such as pigments and fillers. These adsorbents are perfect for improving surface smoothness, minimizing weathering effects, removing foaming and bubbling, and lengthening shelf and pot life.
Typical Specifications & Grades
| Grade | Pore Size | Typical Use | Typical Specification* |
|---|---|---|---|
| 3A Powder | ~3 Å | Polyurethane adhesives, sealants, powder coatings | Water adsorption ≥ 20 wt% (RH60%, 25 °C) |
| 4A Powder | ~4 Å | Broader CASE systems with mixed resins | Bulk density ≥ 0.40 g/mL, moisture content ≤ 3% |
Applications
Powder Coatings
When manufacturing powder coatings, moisture in the resin or filler can cause bubbling, poor adhesion or finish defects after curing. The addition of molecular sieve powder helps maintain ultra dry conditions, improving surface smoothness and defect free output.Sealants
In silicone, polysulphide or polyurethane sealant systems, even sub ppm water can trigger unwanted reactions or CO₂ evolution. Molecular sieve powders ensure formulation stability, consistent cure and long service life.
Adhesives
Structural adhesives, film adhesives and pressure sensitive systems all demand moisture controlled environments for optimal performance. The right molecular sieve powder keeps filler/resin moisture in check and maximises adhesion strength and durability.
