Section
| HS Code | 933749 |
| Product Name | DOWSIL AFE-7500 63.5% Active Concentrated Silicone Antifoam Emulsion |
| Appearance | Milky white liquid |
| Active Content | 63.5% silicone active |
| Continuous Phase | Water (aqueous emulsion) |
| Ionic Character | Nonionic |
| Dilutability | Dilutable with water at ratios from 1:10 to 1:100 depending on application |
| Specific Gravity | Approximately 1.0 at 25°C |
| Viscosity | Moderately high emulsion viscosity, typical Brookfield range around 1000–4000 cP at 25°C |
| Ph Value | Typically in the range of 7.0–8.5 for a 1% aqueous dispersion |
| Antifoam Performance | Rapid knockdown and durable antifoam activity |
| Emulsion Particle Size | Fine particle size for good stability and dispersion |
| Freeze Thaw Stability | May be affected; recommend storage above freezing and mixing before use |
| Recommended Storage Temperature | 5°C to 35°C |
| Shelf Life | Best performance within 12 months from date of manufacture under sealed conditions |
| Application Ph Range | Effective in pH ranges from acidic to mildly alkaline |
| Processing Stability | Stable in many industrial foaming media including wastewater and textiles |
As an accredited DOWSIL AFE-7500 63.5% Active Concentrated Silicone Antifoam Emulsion factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Packaged in 55-gallon drums and 5-gallon pails; DOWSIL AFE-7500 is a 63.5% active concentrated silicone antifoam emulsion. |
| Container Loading (20′ FCL) | A 20-foot FCL loaded with drums of DOWSIL AFE-7500 silicone antifoam emulsion, securely palletized, labeled, and ventilated for safe chemical transport. |
| Shipping | DOWSIL AFE-7500 is shipped in sealed drums or totes to prevent leakage and contamination. Store between 5°C and 40°C, protect from freezing. Not classified as hazardous for transport, but use proper labeling and secure loading. Avoid prolonged high heat; standard freight with temperature protection is recommended. |
| Storage | Store in original, tightly sealed containers in a cool, dry, well-ventilated area away from direct sunlight and incompatible materials. Maintain temperatures between 5–40°C (41–104°F). Prevent freezing, as this can break the emulsion. Avoid contamination by water or foreign matter. Under recommended conditions, shelf life is typically 12 months from date of manufacture. |
| Shelf Life | Shelf life is 12 months from date of manufacture if stored unopened in original container below 25°C; avoid freezing. |
In kraft pulp mills running continuous digesters with post-cooking blow tanks and vacuum drum washers, alkaline black liquor containing saponified tall oil soaps, alkali lignin fragments, sodium sulfide, and sodium carbonate generates persistent foam across the screen room, filtrate tanks, and weak black liquor storage. Foam carryover reduces vacuum drum washer throughput by blanketing the filtration surface, alters mat consistency, and can increase black liquor evaporation steam demand when entrained solids enter the multiple-effect evaporator train. DOWSIL AFE-7500 63.5% active concentrated silicone antifoam emulsion is dosed as a diluted 1:10 to 1:20 water dispersion into the blow line, screen room feed, or filtrate tank inlet. Typical addition rates on continuous kraft lines range from 20 g to 80 g of as-supplied emulsion per dry tonne of bleached or unbleached pulp when foam is generated primarily by residual black liquor soaps. The dosage is not linear above approximately 100 g/t because excess antifoam may deposit silicone on washer wire or downstream bleaching stages if carry-over exceeds the retention capacity of the pulp mat. Compliance for pulp and paper processing is evaluated against the EU BAT Reference Document for the Production of Pulp, Paper and Board, with foam-control efficacy screened by ASTM E2407 using a recirculating foam cell. Migration limits for food-contact paper and board must be separately verified under EU Regulation (EC) No 1935/2004 and national BfR recommendations when the furnish is intended for packaging. Downstream process compatibility is confirmed by monitoring first extraction stage chlorine dioxide consumption and final sheet Cobb values when the antifoam is applied before oxygen delignification. Published data for this specific configuration is limited at addition rates above 120 g/t, so mill trials require headbox deposit inspection and black liquor soap skimming tests. Terminal product types include bleached and unbleached kraft pulp, paperboard, linerboard, and food-contact packaging grades where separate compliance verification applies.
In polyester, polyamide, and cellulosic piece-dyeing operations using high-temperature jet or overflow machines, the circulation pump draws liquor from the vessel sump through a heat exchanger and injects it through a venturi nozzle at nozzle pressures typically between 1.2 bar and 3.5 bar. Dissolved and dispersed auxiliaries, including fatty alcohol ethoxylates, modified polyester oligomers, residual knitting lubricants, and carrier residues, stabilise a coarse air-entrained foam layer in the sump when the fabric rope cycles at 250 to 600 m/min. A foam head of 30 to 80 cm in the draw-off zone reduces the net positive suction head available to the centrifugal pump, producing cavitation pressure pulses and intermittent rope transport stalling. DOWSIL AFE-7500 is pre-dispersed at a 1:5 to 1:10 ratio in cold water and metered into the sump suction side during the first 10 min of the heating ramp. Addition rates in jet units, package conversion machines, and jiggers range from 0.05 g/L to 0.25 g/L of emulsion based on total bath volume, with the higher band reserved for exhaust dyeing of heavy polyester fleece with high residual oligomer content. Restricted-substance compliance is assessed under ZDHC MRSL v3.1 and applicable brand RSL packs, while the product must be cleared against EU REACH Article 33 and candidate list obligations. Foaming in textile process liquors is screened by DIN 53902-1 or by ASTM E2407 in pump-simulated shear loops. The terminal output includes jet-dyed outerwear, automotive seat fabric, and industrial polyester webbing where residual surface silicone can influence heat transfer printing or subsequent lamination bonding. For such grades a pre-trial lamination bond-strength check under the converter’s internal method is warranted because concentrations above 0.30 g/L may lower initial bond strength.
Conveyorised bottle and crate washers in beverage and dairy operations circulate 0.5% to 2.0% sodium hydroxide solutions at 60°C to 85°C through flood nozzles and high-pressure spray manifolds. Saponified label adhesives, casein residues, beer stone, and alkylbenzene sulfonate-derived cleaning boosters generate foam that reduces spray impingement energy, increases pump air binding, and can overflow effluent channels if the detergent package lacks adequate antifoam capacity. DOWSIL AFE-7500 is incorporated into formulated industrial CIP detergents at 0.05% to 0.50% by weight as supplied in the concentrated product, equivalent to 5 ppm to 50 ppm as-supplied emulsion in the use solution after product dilution. The product is mixed into the surfactant phase before final pH adjustment to maintain concentrate stability under high-alkaline storage conditions. Foam performance is screened with EN 12728 perforated-disc beating at 40°C in 0.5% NaOH media, with a collapse time below 30 s after 5 min beating being a typical acceptance threshold for bottle-washer formulations. Published data for this specific configuration is limited for carbonate-rich formulations above 4% Na₂CO₃. Compliance under EU Detergent Regulation (EC) No 648/2004 requires all surfactants to meet ultimate aerobic biodegradability under Annex III, and the silicone emulsion is used at levels that do not alter product hazard classification under CLP Regulation (EC) No 1272/2008. Downstream in the plant, inadequate antifoam in CIP return tanks causes cavitation in centrifugal supply pumps, lowering spray impact to below 1.0 bar at the nozzle and leaving label adhesive residues on glass and PET returnable bottles. Terminal formulated products include low-foam bottle-washing additives, dairy CIP alkaline and acidic detergents, and controlled-foam manual cleaning products. Terminal product types exclude hypochlorite-containing automatic dishwashing detergents above 5% available chlorine because the emulsion may separate upon prolonged contact.
Across municipal and industrial activated sludge basins equipped with fine-bubble disc diffusers, foam generated by Nocardioform filamentous bacteria, extracellular polymeric substances, and slowly biodegradable surfactants accumulates as a viscous brown surface mat that reduces oxygen transfer efficiency and can overflow baffle walls into clarifier weirs. DOWSIL AFE-7500 is applied either intermittently as a diluted 1:20 to 1:50 water solution sprayed directly onto the foam surface or continuously into the mixed liquor channel at dosage rates of 1 ppm to 10 ppm as supplied per volume of aeration basin influent. In diffused-air systems with a design standard oxygen transfer efficiency of 5% to 7% per metre submergence, foam collapse restores the clean-water alpha-factor by reducing gas boundary layer resistance but does not substitute for mean cell residence time control of filamentous populations below 5,000 mg/L MLSS. Compliance is governed by the Urban Waste Water Treatment Directive 91/271/EEC effluent permit conditions for COD, suspended solids, and ammonia. The antifoam itself must be confirmed suitable under REACH and national discharge consents, and foam reduction efficacy at laboratory scale is measured with ASTM E2407 using activated sludge mixed liquor. Downstream terminal products include compliant treated effluent discharged to receiving waters or subjected to tertiary filtration, and waste activated sludge that is anaerobically digested or dewatered. Polymer conditioner demand in belt filter presses may shift when silicone residual accumulates in centrate, so bench testing with the actual sludge at 0.5% to 1.0% solids is recommended before full-scale dosing.
Water-based suspension concentrate and suspoemulsion pesticide formulations contain high loads of dispersed active ingredients, lignosulfonates, naphthalene sulfonate condensates, polymeric nonionics, and electrolytes that lower surface tension and stabilise fine air bubbles during horizontal bead milling and final standardisation. In 250 L to 2,000 L agitated formulation vessels with turbine tip speeds above 5 m/s, entrained air increases batch volume measurement error, lowers milling efficiency, and can cause CIPAC persistent foam failures at the specification limit. DOWSIL AFE-7500 is added at 0.05% to 0.30% w/w of the final formulation, typically split between the pre-milling slurry and the let-down tank. The concentrated emulsion reduces air entrainment during bead mill recirculation without creating oil droplet clarity defects in suspension concentrate formulations with mean particle sizes below 5 µm. Compliance for plant protection product formulations is assessed under FAO/WHO pesticide specification guidelines and the persistent foam test CIPAC MT 47.2, while REACH Annex II SDS and UN GHS labelling requirements apply to the formulated product. Downstream production includes suspension concentrate products packaged in HDPE containers, suspoemulsion formulations, and water-dispersible granule spray-fluid conditioning where antifoam carry-over from the active ingredient slurry influences final granule disintegration time. Terminal product types from this processing route are aqueous suspension concentrates, oil-in-water suspoemulsions, and water-soluble liquid fertilisers with pesticide actives. Tank-mix compatibility testing is required with high-hardness water and representative formulation models because silicone antifoam performance can decline above 2,000 ppm CaCO₃ hardness.
Where high-pressure coolant delivery systems in central metalworking fluid reservoirs operate at 20 bar to 70 bar through through-tool drilling lances and grinding wheel nozzles, foam generated by emulsifier-stabilised tramp oil, bacterial byproducts, and high-shear pump cascades reduces coolant flow consistency and can starve tool-chip interfaces at spindle speeds above 18,000 rpm. DOWSIL AFE-7500 is dosed at 0.01% to 0.10% by volume of ready-to-use coolant, injected into the return line or into the central sump after a 1:10 dilution with demineralised water. The silicone emulsion is preferentially evaluated in soluble oil, semi-synthetic, and fully synthetic coolants with pH 8.8 to 9.6. Hard water tolerance is verified by dilution with 20 °dH synthetic hard water under ASTM E2407 shear conditions. Compliance for metalworking fluid components is anchored to EU CLP Regulation (EC) No 1272/2008 classification and labelling, EU REACH, and national occupational hygiene dossiers for operator exposure limits. Terminal product types from this application are soluble oil coolants for ferrous machining, semi-synthetic grinding fluids for carbide tool grinding, and synthetic aluminium rolling emulsions where silicone foam control must not interfere with subsequent welding adhesion or conversion coating. Published data for this specific configuration is limited when tramp oil exceeds 8% by volume or when the coolant pH drops below 8.2, so stable operation requires continuous air blowdown and centrifugal tramp oil separation before defoamer dosing.
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DOWSIL AFE-7500 63.5% Active Concentrated Silicone Antifoam Emulsion is supplied as a water-dilutable, oil-in-water emulsion with a nominal silicone active fraction of 63.5 wt%. The continuous phase is water; the dispersed phase comprises silicone antifoam fluid and, where present, hydrophobic solids that enhance breakup of protein-stabilized lamellae. The product is intended for metered addition into foam-generating food-processing operations, including sugar beet extraction and evaporation, yeast fermentation, dairy evaporation, fruit and vegetable washing, brewery whirlpool transfer, and wastewater aeration basins where overhead foam caps are undesirable. Because the product is a concentrate, process engineers calculate dose on an active-silicone mass basis rather than as a volumetric product flow. The model designation DOWSIL AFE-7500 identifies the product within the supplier’s emulsion line; the stated active content differentiates it from lower-solids emulsions such as 10% and 30% active grades. Under U.S. food-processing practice, dimethylpolysiloxane defoamers of this class are evaluated under FDA 21 CFR 173.340 as processing aids, provided residual levels in the finished food are controlled by good manufacturing practice. In the EU, dimethylpolysiloxane is listed as E900 under Regulation (EC) No 1333/2008 for specified food categories; processing-aid status must be confirmed nationally. Production lots may carry kosher or halal certification, but certification is lot-specific and should be verified on the supplier certificate.
Low-temperature dosing skids that are sized for 10% or 30% active emulsions can exhibit suction-side cavitation or tubing collapse when DOWSIL AFE-7500 is substituted without changing the skid design. The viscosity of the concentrated emulsion rises as temperature drops; below a site-dependent handling threshold, the product no longer flows as a uniformly pourable liquid and begins to form a high-viscosity creamed layer near the suction lance. Production-scale experience with similar concentrated emulsions indicates that peristaltic pump shot-volume drift becomes observable when the suction line pressure loss approaches the pump’s vacuum rating. To eliminate this failure mode, dosing skids are specified with short, flooded suction lines, reinforced vacuum-rated tubing, and a positive-displacement pump such as a progressive cavity or low-slip gear pump. The injection point is fitted with a check valve and a dilution water line that enters upstream of a static mixer. A static mixer with 4 to 6 elements produces adequate droplet dispersion before the diluted antifoam stream joins the main process line. Without that mixer, the concentrated emulsion can form an inversion gel that adheres to the pipe wall and periodically sloughs into the process.
In multiple-effect evaporation of sugar or dairy streams, foam carryover into the vapor body is controlled by injecting DOWSIL AFE-7500 into the feed manifold or recirculation loop before the separator. The active silicone dose is optimized through a foam height suppression test. A laboratory sparge-tube apparatus operated according to ASTM E2407 can rank antifoam doses on the actual substrate, but plant-specific recirculating evaporator pilot tests are required for scaling to production. Foam collapse in evaporator bodies is often nonlinear; an incremental increase in active silicone may produce only marginal additional defoaming if dissolved salts and colloidal solids are already destabilizing the foam. In beet sugar evaporation, the addition point is typically the raw juice tank or the first-effect feed line, where the emulsion has time to distribute before bubble nucleation becomes severe. In dairy evaporation, the product may be added into the separator feed line at the latest possible point to avoid long residence time in high-shear recirculation pumps. Because DOWSIL AFE-7500 is concentrated, it is often diluted with softened water or condensate before injection to reduce hardness-induced destabilization in the diluted working stream.
Fermentation processes often involve foam stabilized by extracellular polysaccharides, proteins, and solids. The action of silicone antifoam in such systems depends on droplet transport to the lamella surface and the release of active oil at the air-liquid interface. In a yeast propagator or aerobic bacterial fermenter, DOWSIL AFE-7500 is diluted with sterilized water and dosed into the headspace or into the recirculation loop. The use of sterilized dilution water prevents the formation of a contaminated diluted holding line, which could otherwise seed the fermenter with spoilage organisms. Foam-level control is maintained through a foam probe; the antifoam pump is interlocked to the probe signal to deliver small shots rather than continuous flow. Excess antifoam addition is known to reduce the volumetric oxygen transfer coefficient in aerated broth, and the upper dose limit is often set by dissolved oxygen availability rather than foam collapse. This is a critical boundary for concentrated emulsions: the tendency to increase shot volume may control foam while simultaneously masking oxygen limitation. Published data for this specific formulation in food-grade yeast fermentation is limited, and plant-specific dissolved oxygen logging should accompany any dose increase.
Residual silicone films left from antifoam addition can be a concern in plants where product-contact surfaces are cleaned by hot alkaline CIP and steam sterilisation. Polydimethylsiloxane films may remain on stainless steel if the detergent lacks the necessary wetting and saponification capacity or if rinse temperature is too low. In evaporators and plate heat exchangers, a silicone film reduces heat-transfer coefficient and can interfere with turbidity or optical sensors. CIP validation for silicone removal should include surface swab testing or rinsate analysis for organic silicon, using a method such as inductively coupled plasma optical emission spectrometry for silicon. DOWSIL AFE-7500 should not be introduced directly into CIP chemical tanks; high shear and concentrated alkali can destabilize the emulsion and create sticky agglomerates that block spray balls. Instead, residual product is removed by the CIP program from normal product-contact surfaces. This limitation is not unique to the 63.5% active grade, but concentrated emulsions introduce more silicone per unit of product volume, so the total residual potential is higher if overdosing occurs.
On a mass-balance basis, the 63.5% active concentrate reduces product volume and water freight relative to low-solids emulsions. Delivering 100 kg of active silicone requires approximately 157 kg of DOWSIL AFE-7500, compared with 333 kg of a 30% active emulsion or 1000 kg of a 10% active emulsion. The table below presents this arithmetic comparison. Such concentration advantages must be weighed against the higher as-supplied viscosity, the greater need for controlled inline dilution, and the possibility that emulsifier contribution to foam differs in concentrated form. Unlike paste-type or 100% active silicone fluids, the emulsion is water-dilutable and compatible with standard aqueous dosing hardware, but it may be less persistent in high-temperature evaporator bodies where droplet coalescence is promoted by sustained thermal load. The product is not a direct substitute for a compounded 100% active silicone fluid without re-evaluating addition point and residence time.
| Active silicone concentration (wt%) | Product mass required to deliver 100 kg active silicone | Water co-fed with product |
|---|---|---|
| 10 | 1000 kg | 900 kg |
| 30 | 333 kg | 233 kg |
| 63.5 | 157 kg | 57 kg |
Values are calculated on a simple mass balance and do not account for product density differences, lot-specific active content tolerance, or emulsifier contribution to product mass.
In high-shear injection environments, the concentrated emulsion can undergo shear-induced inversion if low water volume and high mixing speed are combined. This failure mode appears as a rapid viscosity increase, sticky visual texture, and loss of defoaming performance as the oil phase smears on mixer elements. For DOWSIL AFE-7500, inversion risk is minimized by adding the concentrate to water under moderate agitation, not by adding water to the concentrate at high speed. Batch dilution tanks should use radial impellers with low tip speed, and the diluted emulsion should be consumed within the supplier’s recommended hold time to prevent microbial growth and creaming. In food plants, dilution water quality should be tested by ASTM D1126 for hardness and by standard membrane filtration for microbial load; if the diluted stream is held beyond the supplier’s recommended hold time, biocide strategy must be evaluated.
Storage and regulatory compliance are evaluated together at incoming inspection. Incoming specification checks typically include appearance, active content, pH, and specific gravity; the certificate of analysis reports lot-specific values. The product should be stored in closed containers within the temperature range stated on the supplier technical data sheet; typical silicone emulsion storage conditions avoid freeze-thaw cycling and prolonged exposure above the supplier’s maximum storage temperature. Freeze-thaw damage in concentrated emulsions can appear as creaming that does not fully reverse by agitation. Incompatibilities include strong oxidizing acids used in sanitation, concentrated cationic flocculants, and high-shear centrifugal pumps without bypass flow. Compliance in the United States is referenced to FDA 21 CFR 173.340 for defoaming agents used in food processing; in the EU, the active dimethylpolysiloxane is listed as E900 under Regulation (EC) No 1333/2008, but processing-aid status is not harmonized across member states. Lot acceptance documents should include certificate of analysis, regulatory conformity statement, and any kosher or halal certification. Published data for this specific formulation in high-acid beverage pasteurization and low-temperature dairy processing is limited; therefore, process validation should be completed on the actual production line before full-scale supplier qualification.
