Refined mineral oil carrier (75–85%) + non-modified PDMS active (10–20%) + hydrophobic silica + emulsifier blend.

MeFoam-MO is the mineral-oil-carrier silicone defoamer compound — a four-component blend engineered specifically for pulp, paper, and wastewater process water applications: (1) refined mineral oil at 75–85% as the dispersing carrier and primary foam-spreading vehicle; (2) non-modified PDMS at 10–20% as the active silicone foam-rupture agent; (3) hydrophobic silica nucleator at 1–3% to initiate bubble rupture; (4) ethoxylated alcohol or fatty-acid soap emulsifier blend at 1–3% to provide self-emulsification when dosed into the aqueous process water.

SEMITECH supplies MeFoam-MO as a translucent off-white to pale-amber liquid at viscosity 100–300 cP at 25°C, density 0.88–0.92 g/cm³, flash point 150–180°C (mineral oil dominates the flash point). The mineral oil carrier provides three operational advantages over pure-silicone defoamers in pulp/paper/wastewater applications: (1) cost — mineral oil is ~80% cheaper per kg than silicone fluid, and at typical dosing levels (50–500 ppm) the carrier dominates the cost structure; (2) compatibility with the aqueous process water — the emulsifier blend self-disperses on contact with water; (3) reduced silicone residue on the finished substrate — paper mills and pulp mills explicitly avoid silicone-rich defoamers because residual silicone on paper interferes with downstream printing inks, adhesives, and coatings.

Mineral oil spreads on bubble film, silicone phase nucleates rupture, oil residue compatible with paper-making.

MeFoam-MO operates by a hybrid two-mechanism defoaming: (1) the mineral oil phase spreads on the air-water interface of foam bubbles via its lower surface tension (mineral oil ~30 mN/m vs surfactant-stabilised foam at 35–60 mN/m), displacing surfactant and thinning the bubble wall; (2) the silicone-silica phase, dispersed within the mineral oil, nucleates bubble rupture through hydrophobic-particle puncture of the thinning bubble film. The combination provides foam-knockdown kinetics on the order of 30–60 seconds in standard pulp-mill black-liquor foam tests, with persistence of 4–12 hours at typical dosing levels.

• Dosing 50–150 ppm — standard pulp mill brown-stock washer foam control
• Dosing 100–300 ppm — paper-machine wet-end foam suppression
• Dosing 150–500 ppm — wastewater treatment aeration tank foam control
• Dosing 50–200 ppm — petroleum refining and gas processing water-stripping

The trade-off is dosing volume: the mineral-oil-dominant chemistry requires higher absolute dosing (50–500 ppm) than pure-silicone defoamers (5–50 ppm equivalent) to achieve the same defoaming effectiveness — but the lower cost per kg active makes the total dosing cost comparable or lower. Plant-scale dosing systems typically meter MeFoam-MO continuously into the process water stream at a control-loop-determined rate based on real-time foam-height monitoring. Avoid for waterborne paint — the mineral-oil carrier will not self-emulsify into a paint formulation reliably and will cause oil-spot defects on the dried paint film; specify MeFoam-PE Low/High or MeFoam-S for paint applications.

Pulp & paper (largest), wastewater treatment, petroleum refining, gas processing water-stripping.

Pulp and paper mill foam control is the largest single application — brown-stock washers, screen-and-cleaner sections, paper-machine wet-end (the most foam-prone stage of paper-making), and broke-recovery systems. MeFoam-MO at 50–300 ppm continuous dosing provides the foam suppression needed to maintain machine speed and finished-paper sheet quality. The mineral oil carrier is critical here — pure-silicone defoamers leave silicone residue on the finished paper that interferes with downstream offset and roto-gravure printing inks, adhesives for laminate construction, and food-contact coatings on packaging board. The mineral oil residue, by contrast, is fully compatible with all standard paper-finishing operations.

Wastewater treatment plant foam control uses MeFoam-MO at 150–500 ppm on aeration tanks, equalisation basins, and clarifier surfaces where biological-treatment-derived surfactants generate operational foam loads. Petroleum refining and gas processing water-stripping uses MeFoam-MO at 50–200 ppm in sour-water strippers and amine units to suppress foam that would impair vapour-liquid contact in the column. Food-and-beverage processing wastewater uses MeFoam-MO at 100–300 ppm in clarification stages — but switch to MeFoam-FG (food-grade) for processes with potential carry-back to consumable products.

CoA per shipment; 200 kg drums standard for plant-scale; 12-month sealed shelf life; Class III combustible (not flammable).

SEMITECH issues a CoA on every batch with: viscosity at 25°C (Brookfield, target 100–300 cP), active silicone content (FT-IR or solvent extraction, target 12–20%), mineral oil content (FT-IR, target 75–85%), water content (Karl Fischer, target ≤1.0%), flash point (ASTM D93, target 150–180°C), and visual appearance. Standard packing 200 kg HDPE-lined steel drums for pulp/paper plant dosing; 25 kg HDPE pails for sample qualification and small-volume use; 1 t IBC totes available for high-volume continuous-feed customers. MOQ 200 kg per grade. Lead time 1–2 weeks ex-Zhejiang to Asia ports, 4–6 weeks to Europe and North America after sea freight.

Storage: stable under ambient conditions; classified as combustible Class III (flash point 60–93°C is Class II, >93°C is Class III; MeFoam-MO at 150–180°C is firmly Class III) — no flammable storage cabinet required, but standard combustible-liquid handling protocols apply (no open flames near transfer operations, ground all metering equipment for static dissipation). Shelf life 12 months sealed; 9 months for opened drums (slow oxidation of mineral oil at exposed air-liquid interface). REACH and regulatory: REACH-registered for industrial use; not approved for direct food-contact (specify MeFoam-FG for food-process water with potential back-contamination); standard mineral oil + PDMS toxicology profile is acceptable for indirect food-contact (paper products in contact with food via packaging). SDS in EU/GHS format issued with every shipment.

MeFoam-MO is the standard pulp/paper/wastewater defoamer — mineral-oil-carrier chemistry minimises silicone residue on finished substrate while providing cost-effective foam control at 50–500 ppm dosing. 200 kg drum standard packaging for plant-scale continuous-feed dosing. Avoid for waterborne paint (oil-spot defects); avoid for food-contact (specify MeFoam-FG).

SEMITECH stocked grade; CoA per batch.