What is Molecular Sieve Activated Powder?
Molecular sieve powder is the same synthetic zeolite material as molecular sieve beads (3A, 4A, 5A, 13X), but ground to ultra-fine particles (3-5 μm D50). This fine particle size allows the adsorbent to be dispersed directly within paints, coatings, polymer matrices, and sealants — providing in-situ moisture control where fixed-bed adsorption columns are not practical.
The "activated" designation means the powder has been pre-dehydrated to less than 2% moisture content and is ready to use. For high-performance applications (especially polyurethane systems and electronics encapsulation), the powder should be re-activated at 200-300°C before incorporation to restore full adsorption capacity.
Four Standard Grades
1. Molecular Sieve 3A Powder (3 Å pore size)
Selectively adsorbs water while excluding molecules larger than 3 angstroms. The preferred grade for moisture-sensitive applications requiring minimal interference with other formulation components.
- Particle size: D50 3-5 μm (standard), 8-12 μm (medium)
- Water adsorption capacity: ≥20 wt% (at 25°C, 50% RH)
- Surface area: ≥600 m²/g
- Primary applications: One-component polyurethane (1K-PU) moisture scavenger, moisture-curable sealants and adhesives, polyurethane coatings, electronic potting compounds, drying of ethanol and methanol, drying of cracked gas in petrochemical processes
2. Molecular Sieve 4A Powder (4 Å pore size)
The general-purpose desiccant grade. Adsorbs water and molecules up to 4 angstroms including CO₂, NH₃, H₂S, and lower alcohols. The most widely used powder grade.
- Particle size: D50 3-5 μm (standard), 8-12 μm, 20-40 μm (coarse)
- Water adsorption capacity: ≥22 wt% (at 25°C, 50% RH)
- Surface area: ≥700 m²/g
- Primary applications: Desiccant paints and anti-condensation coatings, insulation glass spacer desiccant, water-based paint additive, polymer composite moisture control, adhesive and sealant desiccant, food and pharmaceutical packaging oxygen/moisture scavenger, drying of natural gas and air
3. Molecular Sieve 5A Powder (5 Å pore size)
Adsorbs water and molecules up to 5 angstroms, including normal paraffins (C1-C4), alcohols up to C4, and Freon refrigerants. Used where larger molecule adsorption is required.
- Particle size: D50 3-5 μm, 8-12 μm
- Water adsorption capacity: ≥21 wt% (at 25°C, 50% RH)
- Surface area: ≥600 m²/g
- Primary applications: Normal-paraffin separation, hydrogen purification, refrigerant drying, oxygen production adsorbent, drying of LPG and natural gas, kerosene and jet fuel drying
4. Molecular Sieve 13X Powder (9-10 Å pore size)
The largest pore size grade. Adsorbs water and all molecules up to 9 angstroms including aromatics, branched paraffins, and larger hydrocarbons. Used in specialty gas purification.
- Particle size: D50 3-5 μm, 8-12 μm
- Water adsorption capacity: ≥25 wt% (at 25°C, 50% RH)
- Surface area: ≥500 m²/g
- Primary applications: Air separation prepurification (removing CO₂ and H₂O), natural gas sweetening (H₂S and CO₂ removal), LPG sweetening, hydrogen purification, medical oxygen concentrator adsorbent, R-12 refrigerant drying, hydrocarbon drying
Technical Specifications
Standard Grades (D50 3-5 μm, ultra-fine)
| Parameter | 3A Powder | 4A Powder | 5A Powder | 13X Powder |
|---|---|---|---|---|
| Pore Size (Å) | 3 | 4 | 5 | 9-10 |
| D50 (μm) | 3-5 | 3-5 | 3-5 | 3-5 |
| Top Cut (μm) | ≤15 | ≤15 | ≤15 | ≤15 |
| Water Capacity (wt%, 25°C/50% RH) | ≥20 | ≥22 | ≥21 | ≥25 |
| Surface Area (m²/g) | ≥600 | ≥700 | ≥600 | ≥500 |
| Bulk Density (g/cm³) | 0.4-0.6 | 0.4-0.6 | 0.4-0.6 | 0.4-0.6 |
| pH (5% slurry) | 9-11 | 9-11 | 9-11 | 9-11 |
| Moisture (as-shipped, %) | ≤2.0 | ≤2.0 | ≤2.0 | ≤2.0 |
Coarser Grades (D50 20-40 μm, for spacers and cores)
For insulating glass desiccant and similar applications where coarser particles are preferred, we offer D50 20-40 μm grades. These provide better flow characteristics and lower dust generation during spacer filling. Available in 3A and 4A types. Custom PSD available on request.
Key Uygulamalar
- Desiccant Paints & Coatings: Anti-condensation interior wall paints, marine coatings, automotive underbody coatings — powder actively absorbs moisture and prevents blistering
- Insulating Glass: Mixed into the spacer bar desiccant to adsorb moisture trapped during manufacture and any in-service ingress, preventing fog and condensation between panes
- Polyurethane Systems: Moisture scavenger in 1K-PU sealants, 2K-PU coatings, and polyurethane adhesives — prevents CO₂ bubble formation during cure
- Electronics Encapsulation: Epoxy and silicone potting compounds for electronics — prevents voids and ensures reliable insulation
- Polymer Composites: Moisture management in engineering plastics, masterbatches, and specialty compounds
- Adhesives & Sealants: Prevents moisture-induced bubbling and ensures full cure in silicone, polyurethane, and hybrid sealants
- Pharmaceutical & Food Packaging: Oxygen and moisture scavenger in HDPE bottles, blister packs, and flexible packaging
Why Choose Our Moleküler Elek Tozu?
- 4 grades in stock: 3A / 4A / 5A / 13X — same-day shipping from Shandong warehouse
- Tight PSD control: D50 3-5 μm standard, with narrow distribution (top cut ≤15 μm) for smooth dispersion
- Pre-activated: Moisture content ≤2% on shipment, ready to use in moisture-sensitive applications
- Custom particle sizes: D50 1-3, 3-5, 5-10, 8-12, 20-40, 40-80 μm available on request
- Custom packaging: 25 kg plastic-lined paper bags, 500 kg super sacks, or moisture-barrier vacuum bags for ultra-dry applications
- 15+ years export experience: Trusted by paint, adhesive, and glass manufacturers in 40+ countries
Frequently Asked Questions
What is the difference between molecular sieve powder and molecular sieve beads?
Molecular sieve beads are 1-5 mm spheres used in fixed-bed adsorption columns for gas drying and purification. Molecular sieve powder is the same zeolite material ground to 3-5 micron particles, used as an additive in paints, coatings, polymers, and sealants where the active adsorbent is dispersed within a matrix. Powder provides in-situ moisture control and can be mixed directly into formulations. Beads offer higher capacity per unit volume and are used in dedicated adsorber vessels.
What is molecular sieve powder used for?
Common applications: (1) Desiccant paints and coatings that actively absorb moisture from the substrate, (2) Insulating glass desiccant (mixed into spacer bars) to prevent fogging, (3) Polyurethane and epoxy additives to scavenge residual moisture during cure, (4) Polymer composites for moisture management in electronics encapsulation, (5) Adhesives and sealants to prevent bubble formation, (6) Pharmaceutical and food packaging as oxygen and moisture scavenger.
Which molecular sieve type should I use for desiccant paint?
For desiccant paints and coatings, 3A or 4A molecular sieve powder is most commonly used. 3A powder (3 angstrom pore size) selectively adsorbs water but excludes larger molecules, making it ideal for one-component polyurethane systems and moisture-curable sealants. 4A powder (4 angstrom pore size) is the general-purpose desiccant for water-based paints, coatings, and adhesives. Typical loading: 2-8 wt% of total formulation. Pre-dry the powder to <1% moisture before incorporation.
How is molecular sieve powder pre-dried before use?
Molecular sieve powder is supplied as 'activated' with moisture content <2%, but for high-performance applications (especially polyurethane and electronics encapsulation) it should be re-activated at 200-300°C for 2-4 hours under vacuum or dry nitrogen flow immediately before use. This restores full adsorption capacity. After activation, handle only in dry atmosphere (<10% RH). Some suppliers offer 'pre-activated' powder in sealed moisture-barrier packaging for convenience.
What is the particle size range of your molecular sieve powder?
Standard grades: D50 = 3-5 micron (ultra-fine, for paints and coatings), D50 = 8-12 micron (medium, for polymer composites), D50 = 20-40 micron (coarse, for desiccant cores and spacers). Top-cut controlled to ≤45 micron for fine grades, ≤80 micron for medium grades. Custom PSD available. Surface area ranges 500-700 m²/g depending on type. Loose bulk density 0.4-0.6 g/cm³ for fine powder.