Section
| HS Code | 849177 |
| Product Name | AFE-0020 Low-Activity Silicone Antifoam Emulsion |
| Chemical Type | Silicone antifoam emulsion |
| Active Content | 20% |
| Siloxane Content | Dimethylpolysiloxane dispersed in water |
| Appearance | Milky white homogeneous liquid |
| Viscosity At 25c | 2000 mPa·s |
| Ph At 25c | 6.0 - 8.0 |
| Density At 25c | 1.0 g/cm³ |
| Water Dispersibility | Readily disperses in cold or hot water |
| Emulsifier Type | Nonionic emulsifier system |
| Recommended Dosage | 10 - 500 ppm |
| Storage Conditions | Store at 5°C - 35°C, avoid freezing |
| Shelf Life | 6 months from date of manufacture |
As an accredited AFE-0020 Low-Activity Silicone Antifoam Emulsion factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Available in 55-gallon drums, AFE-0020 Low-Activity Silicone Antifoam Emulsion features a sealed, resealable lid for safe dispensing. |
| Container Loading (20′ FCL) | AFE-0020 Low-Activity Silicone Antifoam Emulsion: 20' FCL loading in secured palletized drums, non-hazardous cargo, properly ventilated and braced for transport. |
| Shipping | AFE-0020 Low-Activity Silicone Antifoam Emulsion ships in sealed drums or IBCs to prevent contamination. Protect from freezing and excessive heat; store between 5–30°C. Non-hazardous per DOT/IMDG, but use proper labeling and secure upright loading. Ensure ventilation in transport areas and avoid prolonged direct sunlight to maintain stability. |
| Storage | Store AFE-0020 in its original, tightly sealed container in a cool, dry, well-ventilated area away from direct sunlight, heat sources, and incompatible oxidizers. Avoid freezing, as this may destabilize the emulsion. Maintain temperatures between 5–35°C. Ensure container remains upright to prevent leakage, and use within the manufacturer’s stated shelf life. |
| Shelf Life | Shelf life is typically 12 months from manufacture when stored in sealed original containers away from extreme heat or freezing. |
In waterborne acrylic and styrene-acrylic architectural coating production, pigment dispersion on a high-speed disperser with Cowles blade peripheral speeds of 18–25 m/s inevitably entrains air because anionic pigment wetting agents and polyacrylate dispersants depress dynamic surface tension below 35 mN/m. The resulting microfoam survives let-down because low-shear propeller agitation cannot rupture the surfactant film at the air-liquid interface. AFE-0020 low-activity silicone antifoam emulsion is metered into the let-down tank at 0.05–0.30 wt% of total formulation, preferably after associative thickener pre-gel addition and before final pH adjustment to 8.0–9.0. Low active silicone solids reduce the risk of gloss haze in satin and semi-gloss topcoats when dried films are evaluated according to ISO 2813 and ASTM D523-14. Over-addition above 0.50 wt% occasionally produces cratering in alkyd-modified acrylic topcoats because the dispersed silicone droplet size is no longer fully wetted by the continuous phase; this boundary is more pronounced in formulations containing fluorosurfactants at 0.1–0.3 wt%. In-process foam control can be monitored by circulating the finished coating through a gear pump at 20 L/min and 25°C, with a maximum acceptable persistent foam height of 2 mm in a 2 L graduated cylinder. For EU architectural decorative coatings, compliance with 2004/42/EC Annex IIA waterborne limit values and REACH Annex XVII entries is required; the silicone emulsion contributes no volatile organic compounds when measured by ISO 11890-2:2020 because the active silicone fraction is nonvolatile at 110°C.
When waterborne flexographic inks are diluted from pH-stabilized concentrate to press-ready viscosity of 18–25 s as measured by ISO 2431:2019 4 mm cup, the combination of diaphragm pump pulsation and return-line agitation creates a dynamic microfoam layer in the ink pan that appears not as large bubbles but as pinholes in solid print areas. AFE-0020 low-activity silicone antifoam emulsion is introduced into the ink sump at 0.10–0.40 wt% of diluted ink, either continuously through a metering pump or as a pre-diluted 1:10 water dispersion added during final viscosity trim. Low active silicone solids are required because excess highly active silicone droplets can plate out on anilox roll surfaces and produce a loss of cell volume transfer, measured indirectly as a drop in optical density to below the target 1.40–1.60 for a black channel on corrugated liner. The defoamer must not reduce ink surface tension below the wetting threshold for untreated polyethylene film, typically 38 mN/m, evaluated by contact angle using ISO 19403-2:2017. In gravure units running 150–300 m/min, collapsed foam must drain rapidly enough to avoid build-up in the doctor blade chamber; process control relies on ASTM E2407-04(2020) for foam persistence and visual inspection for microfoam in a wire-wound drawdown. Strong amine odour and pH drift above 9.5 can accelerate emulsion destabilisation; the ink return line should therefore be operated below 40°C and the emulsion should not be post-added directly into ink formulations below pH 7.0 without validation.
During the hold stage following monomer feed completion, an emulsion polymerisation reactor typically contains residual anionic surfactant at 0.5–1.5 wt% of latex solids, low levels of water-soluble initiator decomposition products, and unfinished polymer particles that stabilise a persistent foam blanket at the liquid surface when the turbine agitator runs at 120–180 rpm. This foam blanket reduces condenser heat-transfer duty, interferes with gravimetric level transmitters, and can carry latex solids into the vacuum stripper, where the pressure drop from 500 to 200 mbar causes immediate expansion and fouling of the packed column. AFE-0020 low-activity silicone antifoam emulsion is added after monomer conversion exceeds 98% and before vacuum stripping at 0.01–0.10 wt% of latex solids, as measured by dry residue according to ISO 3251:2019. The low active silicone content permits foam knockdown without the film-surface defects that high-activity silicone fluids cause in subsequent adhesive coating or pressure-sensitive tape casting. Addition during the nucleation phase is contraindicated because dispersed silicone droplets can compete with monomer micelles and raise coagulum generation; coagulum is measured by filtration through a 100 µm sieve and reported as ISO 4576:2023 wet coagulum. The emulsion is compatible with hydroxyethyl cellulose and polyvinyl alcohol protective colloids, but not with high-solids latex formulations containing 0.2 wt% or more of cationic fixatives; the resulting charge-destabilised silicone droplets accumulate on the reactor wall below the liquid line. Laboratory reactor trials with a 2 L glass vessel and pitched-blade impeller at 250 rpm show that residual foam height after 5 min of nitrogen sparging at 1 L/min decreases from 40 mm to below 5 mm at the upper dosage. Final latex viscosity according to ISO 1652:2022 and particle size distribution according to ISO 22412:2017 remain within batch specification when the defoamer is added as supplied after the reactor temperature has been reduced to 55°C or below.
On a fine paper machine running at 1,200–1,500 m/min, air entrained in the thin-stock approach system is stabilised by anionic trash, starch, and wet-end sizing agents. Foam collapses unevenly after the headbox and creates local basis weight variation of ±1.5 g/m² that is visible as barring in lightweight coated grades. AFE-0020 low-activity silicone antifoam emulsion is fed to the white water silo or the thin-stock line before the headbox at 0.005–0.050 wt% of dry fibre, using a progressive cavity metering pump and a dilution skid that reduces the as-supplied emulsion to 1:20 in clarified white water at 35–45°C. Low activity is essential in closed-loop papermaking because retained silicone above a system-dependent threshold can deposit on forming fabrics and press felts; deposits are detected by TAPPI T 550 om-18 extractives and by a rise in first-pass retention loss. The defoamer must not interfere with alkyl ketene dimer sizing; sizing efficiency is checked by ISO 535:2023 Cobb60 value and by ISO 2470-1:2016 brightness. In board mills producing food-contact packaging, the emulsion must comply with FDA 21 CFR 176.170, FDA 21 CFR 176.180, EU Regulation 1935/2004, and BfR Recommendation XXXVI, with migration testing performed according to EN 1186 as applicable. Dosing above 0.1 wt% of dry fibre in recycled linerboard stock containing high levels of stickies is not recommended because the silicone phase can bind to macrostickies and increase the frequency of sheet holes; published data for this specific configuration is limited, but mill-scale observations indicate that low-activity emulsions reduce this interaction relative to high-viscosity silicone fluids.
Diffused-air activated sludge basins treating municipal wastewater at mixed liquor suspended solids of 4,500–6,000 mg/L sometimes develop a surfactant-driven white foam mat that violates the 30-min settled sludge volume reading and obscures dissolved oxygen probes. AFE-0020 low-activity silicone antifoam emulsion is diluted to 1:10 with secondary effluent and intermittently dosed into the return activated sludge line or the aeration tank influent channel at 0.5–5 ppm by basin volume. The low active silicone content reduces the risk of significantly lowering the alpha factor of fine-bubble diffusers, which is measured by the clean-water oxygen transfer test method of ASCE/EWRI 2-22 and expressed as a ratio between process water and clean water KLa. Over-dosing above 10 ppm in a basin with high oil and grease load carries the risk of emulsion breaking and producing a visible surface film that accumulates on the scum baffle. The defoamer is not a substitute for sludge age control or removal of Nocardia-type filamentous organisms; if filamentous foaming is confirmed by Gram staining and Neisser staining, the process response must include mean cell residence time adjustment before chemical foam control is extended beyond 72 h. Effluent compliance monitoring for residual silicone is not usually required under the Urban Waste Water Treatment Directive 91/271/EEC, but downstream membrane bioreactor installations should validate that the dosage does not increase transmembrane pressure rise above 0.5 kPa/h when monitored over 24 h.
| Application scenario | Measured property | Test method designation | Equipment or probe type |
|---|---|---|---|
| Waterborne architectural coatings | Persistent microfoam under circulation | ASTM E2407-04(2020) | Gear pump circulation rig with 2 L graduated cylinder |
| Flexographic ink | Persistent foam | ASTM E2407-04(2020) | Cylinder inversion apparatus |
| Emulsion polymerization latex | Wet coagulum | ISO 4576:2023 | 100 µm stainless steel sieve |
| Paper white water | Extractives and deposit potential | TAPPI T 550 om-18 | Soxhlet extraction apparatus |
| Wastewater aeration | Oxygen transfer alpha factor | ASCE/EWRI 2-22 | Clean-water oxygen transfer test tank |
| Agrochemical suspension concentrate | Persistent foam | CIPAC MT 47.2 | 100 mL graduated cylinder |
| Textile jet dyeing | Color levelness and wash fastness | ISO 105-A01:2010; ISO 105-C06:2010 | Grey scale and SDC multifibre |
At bottle-filling speeds of 60–120 bottles/min, a 500 g/L aqueous suspension concentrate line experiences fill-volume drift when air bubbles occupy the headspace sensor zone during volumetric piston filling. The foam is generated in the high-shear wet milling step and persists because the formulation contains nonionic block copolymer dispersants and propylene glycol antifreeze that lower dynamic surface tension. AFE-0020 low-activity silicone antifoam emulsion is added during the mill base dilution stage at 0.02–0.20 wt% of the final formulation, after bead mill discharge and before final screening through a 100 µm in-line filter. Low active silicone loading is selected because high-activity silicone oils can destabilise the suspension by adsorbing onto crystalline active ingredient surfaces and causing flocculation; suspensibility is controlled according to CIPAC MT 184 and persistent foam is measured by the CIPAC MT 47.2 cylinder inversion method. In tank-mix dilution, the emulsion must remain inactive during spray-tank recirculation; a compatibility test with 2% ammonium sulphate and 0.25% nonionic adjuvant should show less than 5 mL persistent foam after 1 min of recirculation. The formulation is expected to meet the general requirements of the FAO/WHO Manual on Development and Use of Specifications for Pesticides, with storage stability evaluated according to CIPAC MT 46.3 at 54°C for 14 days. Do not exceed 0.3 wt% in formulations containing high electrolyte concentrations above 200 g/L, because the emulsion can cream and cause filter blocking; published data for this specific formulation type is limited.
High-turbulence jet dyeing of polyester woven fabric at liquor ratios of 1:5–1:8 and fabric circulation speeds of 300–600 m/min entrains air in the jet nozzle, producing a foam bubble that collapses irregularly when the fabric rope changes direction at the J-box exit. This irregular collapse is one cause of crease marks and unlevel uptake with disperse dyes, especially in pale and medium shades. AFE-0020 low-activity silicone antifoam emulsion is metered into the preparation bath or the dye bath after complete dye dispersion at 0.02–0.10 g/L, pre-diluted with 10 L of demineralised water per 1 L of emulsion before injection into the circulation pump suction. Low active silicone solids are chosen to limit the formation of hydrophobic silicone spots on dyed fabric that appear as light marks under oblique illumination; levelness is rated according to ISO 105-A01:2010 grey scale and wash fastness is verified by ISO 105-C06:2010 A1S. The defoamer must not interfere with disperse dye dispersion stability; a filtration test through a 5 µm membrane at 130°C for 30 min should show less than 10 mg of residue per 100 mL of dye bath. In production of Oeko-Tex certified textiles, the emulsion must not contain alkylphenol ethoxylates or perfluorinated compounds above the detection limits of the Oeko-Tex Standard 100 limit values. Avoid direct addition to the fabric surface in rope form; the emulsion should be introduced only into a high-shear circulation loop at a point of continuous dilution.
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AFE-0020 Low-Activity Silicone Antifoam Emulsion is a nonionic oil-in-water emulsion containing 19–21 wt% polydimethylsiloxane, siloxane-hydrophobized fumed silica, emulsifier, and water. The product is supplied as a pumpable white liquid intended for let-down with process water before addition to aqueous production streams where surface-active agents stabilise entrained air. The specification release ranges used for batch acceptance are listed in Table 1. The term low-activity refers to the controlled silicone solids fraction, placing the emulsion between concentrated silicone compounds and dilute ready-to-use formulations. Because the silicone phase is already dispersed in water, cold-water dilution does not require high-shear mixing, and the resulting droplet distribution supports rapid spreading at gas-liquid interfaces with a reduced tendency to form visible surface oil. Typical let-down ratios are 1:5 to 1:20 in demineralised or soft water; dilution with untreated process water having more than 500 ppm calcium hardness should be preceded by jar testing or by using a water-stream injection point that limits local concentration gradients.
| Property | Test method | Specification range |
|---|---|---|
| Appearance | Visual inspection | White opaque liquid |
| pH, as-is | ASTM E70 | 6.5–8.5 |
| Density at 25 °C | ASTM D1475 | 0.99–1.02 g/cm³ |
| Brookfield viscosity, spindle 3, 60 rpm | ISO 2555 | 300–800 mPa·s |
| Non-volatile content, 105 °C, 3 h | ASTM D2369 | 19–21 % |
| Silicone solids | ATR-FTIR calibration | 19–21 % |
| Freeze-thaw stability, 3 cycles | ASTM D3209 | No separation after 3 cycles |
The manufacturing process is controlled to a volume median droplet diameter of 5–15 µm as measured by laser diffraction according to ISO 13320. A bimodal distribution with a fine fraction below 5 µm and a coarse fraction below 30 µm is intentional. The fine droplets provide rapid response at freshly created air-liquid interfaces, while the coarse fraction acts as a reservoir in recirculating systems. If the emulsion is subjected to a high-shear rotor-stator mixer at 104 rpm for more than 5 min, the droplet distribution narrows and long-duration defoaming efficiency can decline. This occurs because excessive shear reduces the size of the coarse reservoir droplets and increases total interfacial area, promoting emulsifier adsorption to the aqueous phase rather than to the foam lamella. Viscosity variation of ±50 mPa·s between production lots is attributable to emulsification heat history and should not be interpreted as activity loss; ASTM E2407 foam collapse time remains within ±10 % of the reference batch for an identical dose in a standard surfactant solution.
The defoaming action is not solely proportional to silicone solids. The emulsion droplet must destabilise at the foam lamella surface to release the silicone-hydrophobised silica particle network. In recirculating systems, the continuous addition point should be located after the header that feeds the greatest air-ingress source—commonly the suction side of a transfer pump or a low-pressure venturi—so that the antifoam is present before bubble stabilisation occurs. For batch systems, a split addition of 60–70 % of the calculated charge at the start of filling and the remainder after 50 % of the batch volume is agitated reduces total dosage by approximately 10–20 % compared with a single slug addition. The required dose is dependent on surfactant concentration rather than total water volume; in a nonionic surfactant solution, representative effective concentrations range from 0.01 wt% to 0.10 wt% of working solution.
High-solids silicone concentrates with 30–100 % active silicone require in-line homogenisers or high-shear mixers to create stable secondary emulsions; incorrectly diluted concentrate can deposit on sizing rolls, doctor blades, or reverse osmosis membranes. AFE-0020 avoids this because the particle size distribution is fixed at manufacture. The trade-off is that a low-activity product requires a higher volumetric dose to deliver the same silicone mass. For an equivalent silicone dose of 20 ppm active silicone, AFE-0020 requires approximately 100 ppm of emulsion, whereas a 50 % active concentrate requires approximately 40 ppm. The low-active grade is therefore selected when pump flow accuracy, dispersion uniformity, and finished-surface defect control outweigh inventory cost. When compared with mineral oil-based defoamers, the silicone chemistry of AFE-0020 provides a lower surface tension between the antifoam droplet and the aqueous phase, but it can carry a higher risk of surface defects if overdosed; the low active content narrows this risk because the maximum silicone concentration delivered during a metering error is finite.
In alkaline black liquor, Kraft pulping, and high-pH denim washing, foam is stabilised by lignin fragments and saponified fatty acids. Hydrophobic silica in the silicone emulsion acts as a perforation solid; its contact angle at the oil-water-air interface remains effective until pH and temperature attack the silica surface. Published literature on silicone defoamers in alkaline pulping shows accelerated loss of activity above 70 °C due to silica wetting; equivalent published data for this specific emulsion under continuous Kraft digester conditions is limited. Continuous exposure above 85 °C in black liquor should therefore be qualified by mill trial. In lower-temperature alkaline baths such as metal finishing soak cleaners at 60–70 °C, AFE-0020 is typically dosed into the cascade after the cleaner exits the filter screen, because the high-surfactant load does not permit accumulation in the sludge tank. Avoid combination with amine-based additives in closed-loop heated baths where the amines are used as vapour-space corrosion inhibitors; the resulting pH shift can reduce emulsion stability.
For indirect food-contact applications, the emulsion is formulated from organosiloxanes and siloxane-hydrophobized silica described by the component inventories referenced in FDA 21 CFR 176.210 and 176.200. The information in Table 2 is a regulatory reference matrix, not an independent food-contact approval. Formulators must verify that the finished article meets applicable migration conditions, including overall and specific migration limits, for the intended food type and temperature profile.
| Regulation or standard | Scope | Condition relevant to AFE-0020 |
|---|---|---|
| FDA 21 CFR 176.210 | Defoaming agents used in the manufacture of paper and paperboard | Component inventory and finished-article addition level limitations apply |
| FDA 21 CFR 176.200 | Defoaming agents used in coatings | Component inventory applies; no direct food-contact clearance is conferred |
| EU Regulation (EC) No 10/2011 | Plastic materials and articles intended for food contact | Overall migration limit of 10 mg/dm² applies to the final article |
| REACH Regulation (EC) No 1907/2006 | Registration and SVHC content | SVHC content below 0.1 % w/w in the emulsion |
| RoHS Directive 2011/65/EU | Restriction of hazardous substances | Pb, Hg, Cd, Cr(VI), PBB, PBDE not present above 0.1 % by weight in homogeneous material |
The nonionic emulsifier package provides tolerance to anionic surfactants but not unlimited tolerance to hard water. At calcium hardness above 500 ppm as CaCO₃ and pH above 9.0, fatty acid-soaped systems may form lime soaps; the silicone emulsion can be trapped in the precipitate and removed by clarifier rake arms. Pilot-scale tests in paper machine save-all water with 700–900 ppm hardness show that a 1:10 pre-dilution in soft water before injection prevents filter-screen plugging. Do not inject neat AFE-0020 into a stagnant chest zone. A positive-displacement metering pump with a stroke frequency below 120 strokes/min and a discharge pressure of 0.5–1.0 bar is suitable for most continuous additions. If dosing into a system containing a high concentration of cationic polyacrylamide flocculant, jar testing is required; the emulsion may co-flocculate with the polymer at the addition point.
Storage should be maintained between 5 °C and 40 °C; freeze-thaw cycling may cause creaming. If frozen, the product should be warmed to 20–25 °C and rolled gently; high-shear mixing is not required and may destabilise the emulsion. Packaging in 200 L HDPE drums and 1000 L IBCs is standard. Under these conditions, a batch retains its specification properties for 12 months from the date of manufacture. The product should not be stored in mild steel vessels because pitting corrosion may introduce iron ions that catalyse oxidative cracking of the silicone oil; use 316L stainless steel, polypropylene, or HDPE wetted parts. In recirculating lines, design flow velocities of 0.5–1.5 m/s avoid both settling and excessive pipe shear. A diaphragm pump with PTFE checks is preferred over gear pumps when the product is recirculated for more than 4 h per shift.
In water-miscible metalworking fluids containing 5–10 % mineral oil and alkanolamine corrosion inhibitors, foam is generated by high-pressure coolant delivery through nozzles at 10–20 L/min. AFE-0020 is added to the central sump at 0.02–0.05 % of sump volume, preferably by an automatic dosing unit triggered by an ultrasonic foam sensor. Because the emulsion is low-activity, in-tank accumulation on waylube separators is less frequent than with high-solids products. Oil mist collectors and tramp oil skimmers can remove silicone along with tramp oil; therefore, re-dosing after skimming cycles is required. In high-velocity machining centres with filtration units below 20 µm, the antifoam may be partially filtered; the dosing point should therefore be located after the pressure filter and before the coolant return manifold.
Air-entrained microfoam in blade coating at machine speeds above 900 m/min contributes to blisters, skipped coating, and sheet breaks. Addition of 0.05–0.10 % based on dry coating solids to the coating colour before the deaeration screen reduces microfoam without changing high-shear rheology measured on an ACAV A2 capillary viscometer at 105 s⁻¹. Low-activity silicone is preferred over high-solids concentrates in this application because the pre-dispersed droplet size limits crater formation in styrene-butadiene latex-containing formulations. However, the product should not be added directly to the letdown tank without agitation; a side-stream dilution of 1:10 into a static mixer with 3–5 mixing elements is sufficient.
In can coatings based on amine-neutralised acrylic or epoxy-acrylate resins, the defoaming efficiency of AFE-0020 is influenced by addition order and pH. When the emulsion is added to the grind paste before the amine neutraliser, the silicone droplets are stabilised by pigment wetting agents and do not coalesce prematurely. When the same dose is post-added after amine neutralisation, the pH above 8.5 can reduce emulsion droplet stability and produce macroscopic fisheyes in a drawdown bar test. For a 200 kg production batch with 25 % volume solids, a dosage of 0.05–0.08 % on total weight is typically added to the high-shear mix tank during pigment dispersion. The fineness of grind measured according to ISO 1524 should remain below 15 µm, and the absence of cratering should be confirmed by a BYK-Gardner wave-scan differential scan of a coil-coated panel before filling.
In aerobic fermentation broths, silicone antifoams may affect the oxygen transfer coefficient if the emulsion is added too late in the growth phase. Published data for AFE-0020 in microbial fermentation is limited. Bench-scale evaluation in a 2 L stirred-tank bioreactor at a volumetric oxygen transfer coefficient of 100 h⁻¹ is required before scaling to seed trains. Typical addition rates in bacterial fermentation are 0.005–0.02 % of broth volume; the low-activity grade allows fine dosing but may be less efficient in concentrated molasses media than high-solids silicone compounds.
