Section
| HS Code | 224398 |
| Chemical Family | Silicone compound (polydimethylsiloxane with hydrophobic silica) |
| Appearance | White to off-white viscous paste/compound |
| Non Volatile Content | Approximately 100% by weight |
| Active Silicone Content | 100% by weight |
| Viscosity At 25c | Approximately 10,000–60,000 mPa·s (shear-dependent) |
| Density At 25c | Approximately 1.00 g/cm³ |
| Flash Point | Greater than 200°C |
| Solvent Solubility | Soluble/dispersible in aliphatic, aromatic and chlorinated solvents and in mineral oils |
| Thermal Stability | Stable up to about 150°C; withstands short-term higher temperatures |
| Ph Range | Approximately neutral (5–7) when dispersed in water |
| Storage Condition | Store in original sealed containers at 5–30°C |
| Shelf Life | At least 12 months from production date in unopened container |
As an accredited SILFOAM SC 201 Silicone Antifoam Compound factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | SILFOAM SC 201 Silicone Antifoam Compound is supplied in 25 kg pails as a stable silicone emulsion for effective foam control. |
| Container Loading (20′ FCL) | The 20′ FCL loading of SILFOAM SC 201 uses palletized, shrink-wrapped drums/pails, securely braced to prevent shifting during transit. |
| Shipping | SILFOAM SC 201 Silicone Antifoam Compound is non-hazardous for transport, shipping in sealed drums, pails, or bulk containers. Keep containers upright, dry, and protected from extreme heat or freezing. Avoid direct sunlight and rough handling to preserve product integrity and ensure safe, efficient delivery. |
| Storage | Store SILFOAM SC 201 in its original, tightly sealed container in a cool, dry, well-ventilated area away from direct sunlight, heat, and ignition sources. Keep separated from strong oxidizing agents and incompatible chemicals. Avoid contamination by moisture or foreign matter. Maintain recommended temperatures, protect from freezing, and use within stated shelf life for optimal performance. |
| Shelf Life | Shelf life is typically 24 months from manufacture when stored in original, unopened containers at moderate temperatures. |
Stable foam in a hot spray-tower detergent slurry is controlled by injecting the anhydrous silicone compound into the slurry buffer tank at a point where the top-entering agitator provides a tip speed of 3–5 m/s. SILFOAM SC 201 is metered at 0.05–0.40 % w/w of the slurry batch; the lower end of the range is applied to nonionic alcohol ethoxylate systems with low soap carryover, and the upper end is reserved for high-fatty-acid laundry slurries that contain more than 4 % w/w sodium soap. The dispersion should be completed before the slurry reaches the tower high-pressure pump because entrained air induces cavitation and mass-flow instability in the pump head, which directly shifts the droplet-size distribution in the spray nozzles and may create oversize agglomerates or dusty fines in the dried powder. Foam knockdown is evaluated by ASTM D1173 using a 50 mL aliquot at 60 °C; a common plant acceptance criterion is a collapse time below 45 s for a 0.1 % w/w dispersion, but published data for SILFOAM SC 201 in high-solids tower feed is limited outside the manufacturer’s technical documentation, so the acceptance range must be confirmed through pilot-batch trials. The compound is added before the slurry is aged because prolonged residence time above 30 min under intensive agitation can lower antifoam efficiency in some formulations. Compliance evaluation falls under the Detergent Regulation (EC) No 648/2004 and general REACH registration obligations; the finished product is a low-density spray-dried laundry powder whose residual silicone partitions onto granule surfaces after drying, contributing to end-use foam control in the washing machine.
For slurries held at 65–75 % w/w solids and processed at 80–90 °C, the antifoam compound is added through a side-stream homogenizer only when the in-tank agitator cannot generate sufficient shear; otherwise the high shear can create submicronic silicone droplets that may remain dispersed in the final powder and interfere with optical brightener adhesion. The operational boundary is therefore a maximum homogenizer tip speed of 15–25 m/s and a residence time not exceeding 30 s. If ambient storage is below 10 °C, the compound’s viscosity increases and the transfer line must be heat-traced to maintain volumetric metering accuracy.
Low-water automatic dishwasher detergent gels typically contain 0.05–0.20 % w/w of SILFOAM SC 201, predispersed in the nonionic surfactant phase before the alkaline builder slurry is added, because direct powder addition into a silicate-thickened gel can form localized agglomerates that remain visible as gel specks. In phosphate-free formulations based on citrate or MGDA builders, the foam source is often the combination of protein soil carryover and low-foam nonionic surfactants under the high-shear spray arms; the antifoam compound is required to provide both initial deaeration during gel filling and persistence through 45–60 °C wash cycles. The finished product is packaged as a gel cartridge or stand-up pouch, and the antifoam must not reduce the yield stress of the gel below the threshold for dose stability. Evaluation uses DIN EN 12728 or ISO 696:1981 for foaming power, with a plant acceptance criterion that foam volume after 60 s remain below 50 mL under a 0.1 % w/w test dispersion. Published data for this specific gel configuration is limited; therefore, pilot trials at gel viscosities commonly encountered in low-water automatic dish products are necessary to validate the interaction between the silicone shear-thinning response and the final gel rheology. The product is not a replacement for a defoamer grade approved under FDA 21 CFR 173.340 when the gel is sold for food-contact scenarios.
Storage stability tests are conducted at 40 °C for 28 days, and phase separation is considered unacceptable if the clear silicone layer exceeds 0.5 vol% after 24 h at rest. The antifoam compound should not be combined with long-chain amine oxide gel stabilizers at concentrations above 2 % w/w because salt-mediated phase inversion can reduce foam control in the wash. The operational limit is therefore tied to the specific builder/surfactant ratio, not to a universal dosing rule.
In polyester and polyamide jet dyeing at liquor ratios below 1:8, SILFOAM SC 201 is prediluted with cold process water to a 1–5 % w/w pumpable dispersion and injected into the bath circulation line at 0.05–0.30 g/L of the total liquor volume, with the higher dose applied when the fabric load contains heavily pre-scoured knits that release residual lubricants. The compound is metered before the jet nozzle to prevent foam from accumulating in the rope-circulation zone where bubble collapse instability causes rope slip and contact-time variability. If the dyebath contains cationic dye-fixing agents or high electrolyte concentrations above 10 g/L, the silicone dispersion can lose stability; in such cases, a compatibility test in the actual dyebath should be conducted before bulk dosing. The final product is a dyed fabric, and the residual silicone level on the finished article should be verified against the mill’s downstream heat-transfer print or coating specification because any surface free silicone can affect fluorochemical water-repellent finishing. The use of the compound in textile wet processing is assessed against general REACH requirements and, where relevant, the textile manufacturer’s restricted substance list requires confirmation that no unreacted cyclosiloxane exceeds the buyer’s threshold. Published data for SILFOAM SC 201 in closed high-temperature polyester dyeing is limited, so plant-specific trial work is required for foam collapse time and dyebath spotting.
In a municipal activated sludge basin with an MLSS of 2–5 g/L and an SRT of 8–20 days, the compound is injected as a continuous drip into the mixed liquor channel or the aeration basin influent box at 1–10 mg/L of influent flow, with the upper end reserved for seasonal Nocardia-type foam events. The addition point should be upstream of the aeration grid so that the silicone can spread across the surface film and destabilize the monomolecular layer that stabilizes fine-bubble foam. For final clarifier scum control, a variable-speed metering pump delivers the compound through a 1/4 inch chemical line to the scum collection trough; direct slug dosing is not recommended because high local concentrations above 20 mg/L can increase effluent turbidity and reduce the effectiveness of downstream UV disinfection. Foam-persistence testing uses ASTM D3519 or equivalent sparging apparatus; the operator acceptance criterion is generally a foam height below 10 mm after 5 min in a mixed-liquor sample. The finished product is clarified secondary effluent, and the treatment objective is to maintain surface transfer without exceeding the plant’s total silicon discharge consent. Compliance verification should include the local wastewater permit and any end-of-pipe REACH environmental exposure obligations; the compound is not intended for potable water contact or for direct discharge to surface water.
Excessive dosing above 20 mg/L or repeated slug additions have been associated with floc carryover in plants that use long-chain polymer flocculants; the mechanism is physical adsorption of the antifoam onto the floc surface, not chemical interference. Published data for SILFOAM SC 201 in aeration basins is limited; the dose-response should therefore be re-established after any change in primary sludge age or after a storm event that shifts the influent surfactant load.
| Process system | Indicative dosing range | Test method | Critical limit or note |
|---|---|---|---|
| Spray-tower detergent slurry | 0.05–0.40 % w/w | ASTM D1173 | Disperse before high-pressure pump; avoid homogenizer tip speed above 25 m/s |
| Automatic dish detergent gel | 0.05–0.20 % w/w | DIN EN 12728 | Predisperse in nonionic phase; check yield stress stability |
| Textile jet dyeing | 0.05–0.30 g/L | ASTM D3519 or equivalent | Conduct dyebath compatibility test above 10 g/L electrolyte |
| Municipal activated sludge | 1–10 mg/L | ASTM D3519 | Avoid slug dosing above 20 mg/L; monitor UV transmittance |
| Kraft black liquor evaporation | 0.1–1.0 kg/t dry solids | Plant-specific sparge test | Verify recovery boiler and precipitator compatibility |
| Agrochemical suspension concentrate | 0.05–0.30 % w/w | CIPAC MT 47.3 | Add before wetting/dispersing stage; assess storage at 54 °C |
| CIP spray-wash tank | 0.01–0.10 % v/v | ISO 696:1981 | Dose after caustic or acid; confirm rinse water free of visible film |
| Metalworking fluid central filtration | 0.01–0.10 % v/v | Visual coalescer feed check | Adjust to maintain bubble-free tramp-oil coalescer feed |
When black liquor foam carries over from the flash tanks into the multiple-effect evaporator vapor bodies, a deaeration compound may be injected into the weak black liquor feed at 0.1–1.0 kg/t of dry solids. SILFOAM SC 201 is added to the weak black liquor storage tank before the first effect, where the residual heat and high mixing intensity distribute the silicone across the liquor-air interface; the objective is to reduce foam carryover so that the vapor-side pressure drop remains below the plant-specific threshold and the evaporator can maintain the target black liquor solids of 70–80 % w/w. In the kraft process the liquor pH is typically 12–13, and the compound must be stable under high alkalinity and high dissolved lignin concentration. The final product is a more concentrated black liquor fired in the recovery boiler, and any silicone must be evaluated for its effect on recovery boiler deposition and electrostatic precipitator performance. The standard evaluation method for foam reduction in black liquor is plant-specific rather than governed by a single ASTM or ISO code; published data for SILFOAM SC 201 in this specific configuration is limited, so pilot trials are required to confirm carryover reduction and liquor-pump cavitation response.
In pesticide suspension concentrate bead milling, the compound is introduced into the millbase at 0.05–0.30 % w/w of the total formulation, before the wetting/dispersing stage. The air entrained by high-speed dispersion and bead-mill grinding is the main driver for foam, which reduces the effective mill chamber volume and leads to inconsistent particle-size reduction curves in a horizontal bead mill with a chamber filling ratio of 70–85 %. The silicone compound lowers the air-liquid interfacial elasticity, allowing the air to disengage in the letdown tank before packaging; the final product is a stable aqueous suspension concentrate. Foam is assessed by CIPAC MT 47.3 or an equivalent ASTM D3519 sparge method, and the acceptance criterion is usually a foam height below 25 mm after 1 min. Because the formulation is applied to crops, the global registration dossier must address the silicone inert status under the relevant crop protection regulatory framework, and the compound should be checked against FAO/WHO specifications for inert ingredients. Published data for SILFOAM SC 201 in pesticide suspension concentrates is limited; therefore, the actual dose must be derived from millbase foaming tendency and storage stability at 54 °C for 14 days.
In clean-in-place skid circuits where spray balls operate at 1.5–3.0 bar supply pressure, entrained air in alkaline or acid detergent tanks reduces spray impingement and can extend the cleaning cycle. SILFOAM SC 201 is injected into the wash-tank recirculation line at 0.01–0.10 % v/v of the cleaning solution, and the compound is added after the caustic or acid has been dosed to avoid emulsion inversion at high ionic strength. The foam control target is not to eliminate all surface foam but to prevent the suction line from drawing air into the CIP supply pump. The final product is a cleaned process surface, and the relevant validation sets the final rinse water free of visible silicone film; compliance with food-contact restrictions is not automatic and must be verified if the cleaned surface touches food. The compound should not be used in direct food-contact cleaning where FDA 21 CFR 173.340 or equivalent approval is required.
For soluble-oil metalworking fluid sumps returned to central filtration, the compound is dosed at 0.01–0.10 % v/v into the return line using a volumetric metering pump; the foam source is circulating pump air entrainment, and the dose is adjusted to maintain a bubble-free tramp-oil coalescer feed. No further process elaboration is required beyond routine sump-level monitoring.
Competitive SILFOAM SC 201 Silicone Antifoam Compound prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615380400285 or mail to sales2@liwei-chem.com.
We will respond to you as soon as possible.
Tel: +8615380400285
Email: sales2@liwei-chem.com
Flexible payment, competitive price, premium service - Inquire now!
SILFOAM SC 201 is an anhydrous silicone antifoam compound composed of polydimethylsiloxane fluid and dispersed hydrophobic fumed silica. The material is supplied as a white to off-white paste with a nominal active content of 100%; the absence of water and added preservative distinguishes it from ready-to-use emulsion antifoams. At 25 °C, density measured according to ISO 2811-1 is typically 0.98 g/cm³ to 1.02 g/cm³, and dynamic viscosity measured according to ISO 3219 is typically 1,500 mPa·s to 3,500 mPa·s. Because the product is a silica-filled paste, its apparent viscosity is method-dependent and declines under shear; it should be treated as a thixotropic concentrate rather than a Newtonian pumpable oil.
The hydrophobic silica particles embedded in the silicone matrix provide mechanical foam-film breaking capacity that is not present in unfilled polydimethylsiloxane fluids. However, the compound does not self-disperse in water. For aqueous applications, a predispersion or emulsification step is required before the product can function as a process defoamer. The non-volatile matter determined by DIN EN ISO 3251 is typically not less than 99.0%. The product is therefore positioned as a high-solids antifoam building block for detergent manufacturers, industrial cleaning formulators, and process-chemical blenders rather than as a point-of-use ready-to-dose antifoam.
Defoaming persistence in aqueous surfactant systems is governed by the interaction between the emulsified silicone droplet, the hydrophobic silica surface, and the foam-stabilising surfactant species. In industrial laundry formulations containing linear alkylbenzene sulfonate, fatty alcohol ethoxylate, and citrate builders at pH 9.5 to 11.5, SILFOAM SC 201 is commonly pre-emulsified and screened at an active matter level of 0.005 wt% to 0.050 wt%. Comparative testing may be carried out in a recirculating foam cell following ASTM E2407 at 40 °C; foam volume after a defined shear interval and foam decay time provide batch-to-batch comparison. Published data for this specific compound across all water hardness, temperature, and surfactant combinations is limited, so plant-specific jar testing under actual service conditions is required.
In highly alkaline bottlewashing and clean-in-place formulations containing sodium hydroxide, sodium metasilicate, and sodium hypochlorite, direct injection of the neat compound into the oxidizer tank is not recommended. Concentrated hypochlorite can oxidize the methyl groups of the silicone polymer at elevated temperature, reducing defoamer life. If the compound is required in chlorinated alkaline cleaning lines, it is preferably prediluted into a stabilized nonionic surfactant solution at a ratio of 1:10 to 1:20 and used within 30 min at ambient temperature. The resulting side-stream emulsion should be introduced upstream of a static mixer or inline homogenizer rather than into a low-shear tank zone.
In nonionic and mixed anionic/nonionic surfactant concentrates, the hydrophobic silica in SILFOAM SC 201 improves mechanical shear resistance of the antifoam droplet. This is particularly relevant in continuous bottlewashing lines where sustained recirculation and spray-pump turbulence can strip conventional silicone oils from the air-liquid interface. The compound is less suited to formulations where complete water solubility or transparent appearance is required; polyether siloxane antifoams or organically modified silicone copolymers are preferred in those systems.
Because the product is a paste-like compound with 100% active matter, transfer from drums, pails, or intermediate bulk containers should be performed with positive-displacement equipment. Screw, gear, or rotary lobe pumps with follower plates are appropriate for ambient-temperature discharge. Centrifugal pumps are generally unsuitable for neat product transfer because air entrainment and cavitation at the suction side can produce erratic feed, reduce effective density, and destabilize the silica network. If the plant operates below 15 °C, the viscosity rises sufficiently that insulated feed lines or heated drum jackets are usually required.
For aqueous detergent use, the compound is commonly converted into a 10 wt% to 20 wt% pre-emulsion in water or a water/nonionic surfactant carrier. A rotor-stator mixer operating at a tip speed of 10 m/s to 18 m/s for 10 min to 20 min is a typical starting point. Mixing with a low-shear paddle stirrer is insufficient and generally produces coarse emulsions that separate within 24 h. Laser diffraction can be used to verify dispersion quality; a median droplet size below 10 µm is a practical upper limit for stable aqueous detergent emulsions, although clear low-viscosity formulations may require smaller droplets. The required energy input should be confirmed on the production mixer, since tank geometry, batch height, and mixer diameter significantly affect shear intensity.
In powder detergent manufacture, the compound can be metered into the slurry ahead of the spray-drying tower. Production-scale audits have shown that direct paste injection into the vortex of a low-shear slurry vessel can create localized foam pockets and silica agglomerates. Dosing into a recirculation loop downstream of an inline homogenizer or static mixer reduces these effects. The compound can also be adsorbed onto sodium sulfate or zeolite carriers in a ploughshare mixer, but published data for this specific compound under powder-scale post-addition is limited; homogeneity and foam performance should be validated on the actual carrier system.
Compared with a ready-to-use 20% active silicone emulsion, SILFOAM SC 201 removes approximately 80% of water and emulsifier-package transport mass per unit of active silicone. This reduces storage volume and preservative demand, because the anhydrous compound does not require in-can biocide protection. The trade-off is that the downstream user must supply the emulsification energy, stabilizer chemistry, and quality-control methods needed to convert the compound into a stable process antifoam. Compared with silica-free silicone oils, the fumed silica in SILFOAM SC 201 provides longer foam suppression under mechanical shear. Compared with mineral oil defoamers, the silicone compound has lower surface tension, improved high-temperature resistance, and is typically effective at lower addition levels. Mineral oil types may still be preferred where silicone carry-over is unacceptable or where cost per kilogram dominates and foam loads are low. Compared with water-dispersible polyether siloxane defoamers, SILFOAM SC 201 is not self-emulsifying and does not yield clear solutions; it is therefore less suited to precision parts cleaning, transparent service fluids, or applications where residual antifoam must not produce surface defects in subsequent painting or metallizing operations.
Replacing a 10% or 20% active silicone emulsion in a continuous industrial cleaning line requires modification of dosing hardware rather than a simple volumetric rate adjustment. The dosing skid should be configured with a positive-displacement pump, insulated or heat-traced feed lines if the plant operates below 15 °C, and a water flush valve after the injection point. The neat product is typically prediluted at 1:10 to 1:20 with ambient water or a dilute nonionic surfactant solution and then passed through a static mixer or a small inline rotor-stator device before entering the foam-prone process stream. Introducing the compound into a low-velocity line without continuous mixing can create visible silicone-oil streaks on cleaned glass, product film defects, and uneven defoaming.
Dosing is based on active silicone mass rather than product volume. For a continuous bottlewashing line processing 10,000 L/h, a target active addition of 0.010 wt% corresponds to 1.0 kg/h of active antifoam. Because SILFOAM SC 201 is 100% active, the neat mass flow is also 1.0 kg/h. A comparable 10% active emulsion would require 10.0 kg/h of product for the same active dose. This difference directly affects day-tank sizing, pump capacity, and operator calibration. Feed lines should avoid dead-legs and long vertical rises; the paste can retain air and form plugs when the line cools or when the pump is stopped without flushing.
When the compound is injected into a process stream, the preferred placement is upstream of a high-shear wash pump or an inline mixer with a pressure drop of 0.5 bar to 1.0 bar. Injection downstream of the wash pump may be acceptable only if sufficient turbulent energy exists to disperse the silicone phase. In several industrial audits, foam-control failures were traced to adding the compound at a point of low turbulence, not to insufficient active dosage. Therefore, dispersion quality and injection-point energy should be evaluated before adjusting concentration.
Quality-control release methods for SILFOAM SC 201 are aligned with standard analytical methods. The following matrix is used to verify batch conformity during inbound release; values are typical and may be updated by the manufacturer’s certificate of analysis.
| Property | Method | Typical specification |
|---|---|---|
| Appearance | Visual inspection | White to off-white paste |
| Density at 25 °C | ISO 2811-1 | 0.98 g/cm³ to 1.02 g/cm³ |
| Dynamic viscosity at 25 °C | ISO 3219 | 1,500 mPa·s to 3,500 mPa·s |
| Non-volatile matter | DIN EN ISO 3251 | ≥ 99.0% |
| pH of 10% dispersion | ISO 976 | 6.5 to 8.5 |
| RoHS restricted substances | Directive 2011/65/EU Annex II | Below maximum concentration thresholds |
Indirect food-contact applicability may be documented under FDA 21 CFR 176.170 and FDA 21 CFR 176.180 for paper and paperboard components under specified use conditions. These citations do not constitute direct food additive approval. Use in applications regulated by EU 10/2011 for food-contact plastics must be confirmed against the current manufacturer’s product regulatory sheet, because overall migration limits and specific migration test methods are formulation-specific. Under EU REACH, silicone polymers of this type are generally exempt from polymer registration, but monomer and impurity registrations must be verified through supply-chain documentation. The product is not formulated with alkylphenol ethoxylates or added halogenated solvents. RoHS restrictions are typically met based on the absence of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls, and polybrominated diphenyl ethers above the Annex II thresholds.
Operational boundaries are defined by the hydrophobic silica content and the silicone oil phase. SILFOAM SC 201 should not be used in systems where residual silicone can interfere with electroplating, painting, adhesive bonding, or oxygen-sensitive sensor surfaces. Silicone carry-over can reduce contact angle and impair adhesion; in precision cleaning operations, even trace amounts may be unacceptable. In paper machine white water, the compound may improve foam control but can affect sizing if overdosed. A maximum addition of 0.02 wt% active on dry fibre is sometimes used as a starting point, but published data for this specific compound in acid/alum systems is limited.
Oxidizing environments require special handling. Concentrated hypochlorite, peroxygen systems, and hot oxidizing acids can oxidize the silicone polymer, shorten defoaming life, and generate surface-active fragments that may complicate downstream filtration. In bleaching operations, the compound should be pre-emulsified and added as close to the point of foam generation as possible. Continuous exposure temperatures above 50 °C in aggressive oxidizer-containing media should be validated for the specific formulation. Storage in unrated plastic containers at temperatures above 35 °C is not recommended because paste-like products can deform or permeate through thin-wall containers.
For low-viscosity aqueous cleaners, a formal emulsion stability study at 40 °C for 4 weeks should be performed to determine phase separation and re-dispersibility. Centrifugal stability at 3,000 min⁻¹ for 30 min provides a rapid comparative screen but does not replace storage testing. Material from partially used containers should be protected from moisture; surface condensation can hydrolyze the hydrophobic silica surface and shift defoaming performance. If surface water is present, the affected layer should be discarded rather than re-dispersed into the bulk. In high-solids organic coating applications, the silicone phase may create craters in air-drying alkyd films; if cratering is unacceptable, a polyether siloxane or organically modified acrylic defoamer should be evaluated instead.
