MeFoam-PE High-MW (High Molecular Weight Polyether-Modified Silicone Defoamer): Sustained Anti-Foam Persistence for Shelf-Stable Coatings and Long Production Runs
SEMITECH MeFoam-PE High-MW is the persistence-optimised polyether silicone defoamer for shelf-stable waterborne paint, multi-hour pulp/wastewater process water, and emulsion polymerisation reactors. Higher MW PDMS backbone (Mw 30,000–80,000) gives slower spreading but longer-lasting film integrity. Pair with Low-MW for fast knockdown + sustained persistence. 25 kg HDPE pail, 2–4 week ex-China lead time.
Contents
| Polyether-PDMS | 0.05–0.3% | 200–500 cP |
|---|---|---|
| Chemistry | Typical loading | Viscosity |
Chemistry & Specifications
High-MW polyether-PDMS, 200–500 cP, hydrophobic silica nucleator; longer-lasting bubble-film integrity.
Same polyether-modified PDMS chemistry as Low-MW but Mw 30,000–80,000 g/mol. Viscosity 200–500 cP (4–10x higher than Low-MW). Slower diffusion and spreading, but thicker, more durable spread film giving 12–48 hour anti-foam persistence (vs 1–4 hours for Low-MW). Active content 100% in glycol carrier with 1–3% hydrophobic silica.
Defoaming Mechanism: Slow Spreading + Durable Film for Long Persistence
Same surfactant-displacement mechanism as Low-MW, but slower spreading and more durable interface film.
Knockdown 30–90 seconds (vs 5–15 sec for Low-MW), but persistence 12–48 hours vs 1–4 hours.
- Loading 0.05–0.15% — shelf-stable waterborne paint (12+ month retail shelf-life)
- Loading 0.10–0.20% — emulsion polymerisation reactors (multi-hour cycle times)
- Loading 0.10–0.30% — pulp mill and wastewater process water
- Loading 0.05–0.15% — adhesive emulsions with extended storage requirement
Pairing strategy: dose 0.10% Low-MW at let-down for fast 5–15 sec defoaming, then 0.05% High-MW after 30 min for sustained persistence. Total 0.15% outperforms either grade alone.
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Applications & Formulation Guidance
Shelf-stable waterborne paint, emulsion polymerisation, pulp/wastewater, adhesives with extended storage.
Shelf-stable waterborne paint (largest) — retail-channel emulsion paints with 12–24 month shelf life at 0.05–0.15%. Emulsion polymerisation — PVAc, EVA, styrene-acrylic at 0.10–0.20% for multi-hour cycles. Pulp/wastewater — continuous-feed dosing at 0.10–0.30%. Construction adhesives — waterborne wood glue, tile adhesive at 0.05–0.15%.
Procurement, Storage and Quality Control
CoA per shipment; 25 kg HDPE pail; 12-month sealed shelf life; tolerates ambient handling; non-flammable.
CoA per batch: viscosity (200–500 cP), silicone content (≥98%), silica (1–3%), water (≤0.5%). MOQ 25 kg. Lead time 1–2 weeks Asia, 4–6 weeks Europe/North America. Non-flammable; no nitrogen blanket required. Pre-warm drums to 25–30°C in cold climates for consistent metering. REACH-registered; FDA 21 CFR 175.300 for indirect food-contact.
MeFoam-PE High-MW Specification Sheet
SEMITECH stocked grade; CoA per batch.
| Property | Specification | Test Method |
|---|---|---|
| Chemistry | High-MW polyether-modified PDMS + hydrophobic silica | — |
| Form | 100% active in glycol carrier | — |
| PDMS Mw (typical) | 30,000–80,000 g/mol | GPC |
| Active silicone content | ≥98% | Solvent extraction |
| Hydrophobic silica content | 1–3% | Ash analysis |
| Appearance | Cloudy white to off-white viscous liquid | Visual |
| Density (25°C) | 0.97–1.00 g/cm³ | ASTM D1475 |
| Viscosity (25°C) | 200–500 cP | Brookfield |
| Surface tension (1% aq.) | 22 ± 2 mN/m | Du Noüy ring |
| pH (1% aq.) | 6.0–8.0 | pH meter |
| Water content | ≤0.5% | Karl Fischer |
| Anti-foam persistence (lab test) | 12–48 hr at 0.1% in 0.5% SDS | Internal |
| Flammability | Non-flammable (flash point >150°C) | ASTM D93 |
| Solubility | Self-emulsifies in water; soluble in glycols, esters | — |
| Packaging | 25 kg / 200 kg HDPE pail or drum | — |
| Shelf life | 12 months sealed below 30°C | — |
FAQ
+Why does my retail paint develop foam after 6 months of storage?
Low-MW defoamer re-disperses into the bulk over time. Switch to High-MW at 0.05–0.10% or use Low + High pairing (0.10 + 0.05%). High-MW forms a thicker, more durable interface film lasting 12–48+ hours.
+Is High-MW compatible with my high-shear paint line?
Yes, but dose during high-shear let-down (Cowles 1500+ rpm, 15–30 min) for proper dispersion. If your line cannot accommodate additional shear, request the 50% emulsion form.
+Can I use High-MW alone without Low-MW?
For shelf-stable retail paint where 30–90 sec knockdown is acceptable during manufacturing, High-MW alone at 0.10–0.15% works. For high-throughput lines needing clearance within 30 sec, pair with Low-MW.