| HS Code | 476267 |
| Product Name | Silicone Defoamer RH-9200 |
| Appearance | Milky white to pale yellow liquid |
| Form | Liquid emulsion |
| Chemical Basis | Silicone/polydimethylsiloxane-based defoamer |
| Active Ingredient | Silicone compound |
| Ionic Type | Nonionic |
| Ph | 6.0-8.0 |
| Viscosity | 100-1500 mPa·s at 25°C |
| Density | 0.95-1.10 g/cm³ at 25°C |
| Solid Content | 20-30% |
| Water Solubility | Water-dispersible |
| Dilution Stability | Stable after recommended dilution |
| Flash Point | >100°C |
| Storage Temperature | 5-35°C |
| Shelf Life | 12 months |
| Freeze Stability | Protect from freezing |
| Thermal Stability | Stable under recommended storage conditions |
As an accredited Silicone Defoamer RH-9200 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Silicone Defoamer RH-9200 is packaged in 200 kg plastic drums, with each drum securely sealed for safe transport and storage. |
| Container Loading (20′ FCL) | Silicone Defoamer RH-9200 is loaded into a 20-foot FCL container, securely stowed and braced for safe ocean transport. |
| Shipping | Silicone Defoamer RH-9200 is typically shipped in sealed plastic drums or IBC totes, clearly labeled with product, batch, and safety information. Keep containers upright and closed, avoid freezing or extreme heat, and transport as non-hazardous unless the SDS states otherwise, following local regulations. |
| Storage | Store Silicone Defoamer RH-9200 in a cool, dry, well-ventilated area, away from direct sunlight, heat, ignition sources, and incompatible materials such as strong oxidizers and acids. Keep containers tightly closed and upright to prevent leakage. Protect from freezing and avoid prolonged exposure to extreme temperatures. Use original packaging, do not stack excessively, and follow local regulations and the manufacturer’s safety data sheet. |
| Shelf Life | Shelf life is typically 12 months from manufacture when stored in original, unopened containers under recommended conditions. |
In waterborne architectural coatings, foam is stabilized by three simultaneous letdown-stage events: vortex air entrainment under 6.5–7.0 m/s tip speed, association of polyurethane thickener networks, and surfactant migration to the air–liquid interface. RH-9200 is applied as a split post-mill addition at 0.15–0.35 wt% of total wet coating mass; 60–70% of the dose is introduced before final associative thickener letdown, and the remainder is metered after viscosity adjustment to 90–100 KU at 25°C by ASTM D562. This sequence allows the silicone active to spread over foam lamellae without deflocculating the pigment grind. On production lines, fineness of grind is maintained below 20 µm by ISO 1524:2013 and gloss stability is checked at 60° geometry by ISO 2813. The relevant regulatory boundary is Directive 2004/42/EC Annex IIA for water-based decorative coatings; because defoamer addition contributes to total VOC load, the formulator must verify that the finished coating remains below the applicable subcategory volatile organic compound limit. Downstream, the coating is applied by airless spray, roller, or block brush at wet film thicknesses between 0.021 in and 0.027 in, then force-dried for 20 min at 60°C. Terminal product types include interior semigloss acrylics, exterior flat masonry paints, waterborne wood enamels, and quick-dry wall primers. A production bottleneck appears when the defoamer is added during pigment grinding at shear rates above 10,000 s⁻¹; this creates seed particles that pass only through a 60-mesh bag filter and can increase dry-film scratch sensitivity.
Coating color for solid bleached sulphate board is built from 60–70% ground calcium carbonate, clay, carboxylated styrene–butadiene latex, and starch; at 65% dry solids and 300–500 cP Brookfield viscosity at 100 rpm, air is captured during jet-cooker starch make-down, pigment slurry transfer, and screen filtering. RH-9200 is dosed at 0.05–0.15 wt% on dry pigment mass into the 20,000 L recirculation tank, not into the blade coater supply header, allowing 15–20 min residence time before the color reaches the applicator. At 900–1,500 m/min web speed, a short-dwell head forces color through a 300 µm blade gap and subjects residual foam to rapid pressure drop; the resulting coating skip and streak defects are the primary machine rejection cause. The applicable compliance standard is FDA 21 CFR 176.210 for defoaming agents used in the manufacture of food-contact paper and paperboard; for EU converters, Regulation (EC) No 1935/2004 Article 3 and BfR Recommendation XXXVI define the supporting migration and organoleptic expectations. The coating is applied at 10–15 g/m² dry coat weight, dried by infrared, and calendered at 120–140°C; terminal products include folding carton board, liquid packaging board, pharmaceutical insert board, and metallized label stock. The critical limitation is that addition above 0.3 wt% on dry pigment changes dynamic surface tension balance and produces depressed fisheyes visible only after calendering under 75° gloss inspection per ISO 2813. Because published data for this specific configuration is limited, start-up trials should use a temperature-controlled recirculating foam cell at 45°C rather than extrapolating from static Ross-Miles height.
Venturi jet dyeing at 4:1–6:1 liquor ratio generates foam in the sump when polyester dyeing liquor at 130–135°C or cellulosic dyeing liquor at 60–80°C returns through the transport tube at 2.0–2.5 bar pump pressure and expands into the chamber. RH-9200 is dosed at 0.1–0.4 g/L of dyebath after dye dispersion but before fabric loading, preventing pump cavitation and rope marks without being exhaustively adsorbed onto the fibre surface. In high-salt reactive dyeing, the dose is split 70% at make-up and 30% after salt addition, because salt shock destabilizes dispersed silicone droplets and reduces foam persistence. The compliance benchmark is ZDHC MRSL v3.2, which prohibits APEO, PFOA/PFOS, and organohalogen stabilizers in textile chemical formulations; for articles sold under Oeko-Tex Standard 100 Class I and II, the defoamer formulation is also cleared for residual extractable silicone spots. Downstream production includes overflow rinsing at 60°C, acetic acid neutralization, and stenter drying to 6–8% residual moisture; terminal products include disperse-dyed polyester jersey, reactive-dyed cotton interlock, polyamide-elastane warp-knit, and polyester microfiber cleaning cloth. A specific operational boundary is tight-loop pre-scour liquor containing calcium soaps above 150 mg/L as CaCO₃; at this concentration the silicone emulsion coalesces, forms visible spots on dark shades, and can force a 2 h machine washout before shade continuation.
Foaming in suspension concentrate manufacturing is most severe after wetting of technical active on a high-speed disperser at 1,800 rpm and during recirculation through a 1.4 L horizontal bead mill charged with 0.6–0.8 mm zirconium oxide beads. RH-9200 is introduced at 0.1–0.5% w/w of the total formulation; approximately half is added before milling to suppress foam during bead wetting, and half after milling to control persistent microfoam generated by alkyl naphthalene sulfonate and EO/PO block copolymer adjuvants. The governing foam methodology is CIPAC MT 47.2, with a target below 15 mL persistent foam after 1 min; suspension stability is additionally checked by CIPAC wet sieve retention and pourability methods referenced in the formulation specification. Regulatory conformity is assessed against the FAO/WHO Manual on development and use of FAO and WHO specifications for pesticides, particularly the physical stability and persistent foaming clauses for water-dispersible formulations. Downstream production includes thickening with xanthan gum added as a 5% gel, deaeration under −0.07 MPa vacuum, and HDPE packaging; at farm dilution of 1:200 in spray water, tank-mix foam must remain below 50 mL after recirculation. Terminal products include 480 g/L herbicide SC, 250 g/L fungicide SC, and seed-treatment slurry containing combined insecticide/fungicide actives. An operational boundary occurs above 0.6% w/w: formulation viscosity at 20 rpm Brookfield RVT falls below 400 cP, accelerating sedimentation of particles above 5 µm and invalidating long-term stability under 54°C storage.
Pharmaceutical intermediate wastewater treatment trains operating at 3,000–5,000 mg/L influent COD and 3,000–4,000 mg/L MLSS develop a stable foam layer when extracellular polymeric substances released by Zoogloea spp. stabilize fine-bubble aeration gas. RH-9200 is metered through a PTFE diaphragm pump at 2–10 ppm active defoamer into the aeration basin weir or return activated sludge channel; dosing is velocity-triggered rather than continuous to prevent silicone accumulation in the sludge phase. The compliance anchor is OECD 209 activated sludge respiration inhibition screening, with a target of no more than 10% respiration reduction after 3 h contact at the maximum intended dose; discharge oil and grease is maintained below 10 mg/L n-hexane extract under US EPA 40 CFR Part 133 or equivalent national consent. The downstream process includes dissolved air flotation thickening, belt-press dewatering, and anaerobic digestion of waste sludge; terminal outputs are treated effluent and dewatered sludge cake suitable for land application or incineration. Published data for RH-9200 in this specific configuration is limited; full-scale dosing should be preceded by jar testing with plant mixed liquor at actual basin temperature and by continuous foam-height logging at the weir.
During compounding of 55% solids vinyl acetate-ethylene dispersion adhesives under −0.08 MPa vacuum in 1,000 L anchor-mixed vessels, air is entrained during polyvinyl alcohol protective colloid dissolution and later during plasticizer metering. RH-9200 is added at 0.05–0.2 wt% of wet adhesive after the protective colloid is fully dissolved, because addition during dissolution leads to gel particle formation and filter blockage. The food-contact compliance standard is FDA 21 CFR 175.105 for adhesives used in laminates for food packaging; the converter must verify that the final laminate complies with overall migration limits under Regulation (EC) No 10/2011 when plastic films are involved. Downstream production applies the adhesive by transfer roll coating at 30–80 m/min to 12–40 µm PET or PE film, depositing 2–4 g/m² dry adhesive before drying in a 60–80°C tunnel. Terminal products include paper/paperboard laminates, film-to-film laminates, metallized film packaging, and cold-seal release bases. Addition above 0.25 wt% depresses static surface tension below the substrate wetting threshold and creates adhesive strike-through on porous kraft papers; peel strength can fall below customer specification. The formulation must be kept free of cationic surfactants above 0.1% because charge reversal collapses the silicone emulsion during storage, producing a clear oil layer that cannot be redispersed.
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Silicone Defoamer RH-9200 is specified in industrial aqueous foam-control programs as a water-dilutable silicone emulsion concentrate. The model designation RH-9200 identifies a compounded formulation rather than a single CAS-defined substance; typical silicone defoamer concentrates of this class are built on a continuous water phase, emulsified polydimethylsiloxane fluid, hydrophobized silica particles, and nonionic emulsifiers. Supplier documentation for RH-9200 is limited to application-summary data, and the absence of a publicly accessible certificate of analysis means that batch-specific values for active silicone content, viscosity, and pH should be confirmed with the manufacturer before qualification. Representative property ranges for commercial silicone defoamer emulsions of similar structure include a white to off-white liquid appearance, density of 0.98–1.02 g/cm³ at 25 °C, pH of 6.0–8.0, and active silicone content of 10–30 wt%; these values are class-typical and must not be read as a released specification for RH-9200. The product is added at low mass fractions to aqueous process streams to destabilize entrained air and surface foam through spreading, bridging, and dewetting mechanisms at the air–water interface. Because silicone defoamers reduce surface tension to a greater extent than mineral oil or polyglycol defoamers, dose control is more critical: underdosing leaves persistent foam, while overdosing can produce fisheyes, cratering, or deposition on paper machine clothing.
For procurement and incoming inspection, pH is typically measured by ASTM E70 and viscosity by ISO 2555 using a Brookfield viscometer at 25 °C and 60 rpm; density is determined by a pycnometer or oscillating U-tube according to ISO 2811-1. Because this is an emulsion, freeze–thaw stability, centrifugal stability, and sieve residue are more informative than single-point viscosity. A retained screen test on a 100 µm or 45 µm sieve can reveal agglomerated silica or oil separation not apparent on visual inspection. In practice, production-scale receiving checks should include both hot-box aging at 40 °C for 7 days and a three-cycle freeze–thaw protocol from −5 °C to 25 °C; published data for RH-9200 under these exact conditions is limited, and failure thresholds must be established per supplier specification.
Defoamer selection in aqueous process systems is governed by mechanism, persistence, and downstream compatibility. A silicone emulsion such as RH-9200 functions predominately as a foam breaker by the spreading of low-surface-tension silicone oil over the foam lamella, followed by dewetting and bridge rupture. Mineral oil defoamers rely on higher oil loadings to displace surfactants from the air–water interface, which often introduces hydrophobic oil carryover. Polyether defoamers show lower antifoam efficiency but better compatibility in high-gloss waterborne coatings because they do not create the same low-energy surface defects. The following comparative matrix summarizes operational distinctions in class-representative terms; values for RH-9200 released by the original manufacturer may be narrower and must be verified against the batch certificate.
| Classification | Active chemistry | Typical use concentration in aqueous service | Persistence under shear | Risk in thin-film coatings | Test standard for foam control |
|---|---|---|---|---|---|
| Silicone emulsion, RH-9200 class | Polydimethylsiloxane and hydrophobized silica | 0.5–5 ppm in aeration basins; 0.05–0.20 wt% dry coating solids class-typical | Moderate to high if emulsion remains stable | Fisheye or crater risk if overdosed | ASTM E2407 |
| Mineral oil defoamer | Mineral oil, hydrophobic particles, emulsifiers | 5–50 ppm typical | Low to moderate; oil droplets may coalesce | Gloss reduction, oil spots, overcoat adhesion loss | ASTM E2407 |
| Polyether/polyglycol defoamer | Ethylene oxide/propylene oxide block copolymers | 10–100 ppm typical | High molecular persistence but lower initial knockdown | Lower surface defect risk; intercoat adhesion loss possible at high loading | ASTM E2407 |
| Silicone polyether block copolymer | Siloxane backbone with pendant EO/PO chains | 10–200 ppm typical | Moderate; cloud point can reduce activity | Very low oiling-out tendency | ASTM E2407 |
A further distinction is drawn between conventional silicone emulsions such as RH-9200 and silicone polyether block copolymers. The latter are water-dispersible to nearly clear solutions and show lower risk of oiling-out, but their defoaming efficiency is generally lower at equivalent active concentrations and they may lose activity above their cloud point. In contrast, a conventional silicone oil and hydrophobized silica emulsion retains a defined droplet phase; this structure requires agitation during dilution but delivers stronger spreading behavior at the air–water interface. The choice between the two is therefore not a matter of product superiority but of hydrodynamic shear, rinseability, and required persistence.
On a paper machine wet end, the point of addition determines whether RH-9200 will function as a persistent antifoam or as a transient defoamer. Addition to the suction side of a fan pump or to the white-water silo at 0.02–0.10 wt% of incoming stock is class-typical for silicone emulsion products; however, for RH-9200 the manufacturer’s field data for specific headbox configurations is not publicly available. In a paper coating kitchen, defoamer is often metered as a 1:10 to 1:50 aqueous dilution by a diaphragm metering pump or progressive cavity pump into the pigment slurry during high-shear dispersion. Dilution water quality is important: hard water above 300 mg/L as CaCO₃ or high electrolyte loadings can destabilize a nonionic emulsion before it reaches the foam interface. Equipment construction should use 316L stainless steel or polypropylene wetted parts; copper and brass fittings are not recommended because trace metal ions can accelerate emulsion creaming. In aeration basins, the emulsion should be fed downstream of the aerators or into the clarifier launder rather than directly into the blower manifold; point addition into the mixed liquor channel with a static mixer reduces the probability of localized oil deposition on membranes if the plant has MBR modules.
High-shear mixing in pigment dispersion can over-emulsify some defoamer droplets and reduce knockdown efficiency. For silicone defoamers, the active droplet size and hydrophobic particle distribution control both antifoam activity and the severity of coating defects. A disc disperser or cowles blade generating tip speeds above 10 m/s can shear a defoamer emulsion if added too early; the usual practice is to add defoamer at the letdown stage or after pigment slurry viscosity has stabilized. The coating formulator should evaluate defoamer persistence with a defoaming ability test according to ASTM E2407 or a foam-cell air-release method, and then confirm film appearance by drawdown over black glass or polyester film. Published data for RH-9200 specifically in waterborne acrylic or styrene-butadiene paper coatings is limited; therefore, a ladder study from 0.05 to 0.30 wt% defoamer solids on dry coating binder is a conservative qualification sequence.
Alkaline cleaning and bottle-washing plants present a singular challenge for silicone defoamers because the foam-stabilizing surfactant load is high, the electrolyte content is elevated, and the continuous phase of the defoamer emulsion must resist creaming. Silicone defoamers of the RH-9200 class are typically used in such systems at 5–50 ppm as received, with feed directly into the overflow channel or spray rinse reservoir rather than into the hot wash stage where temperatures exceed 80 °C. The defoamer must be diluted with ambient service water, not steam condensate above 40 °C, to prevent thermal shock inversion. In a bottle washer with 1.0–2.0 wt% NaOH and 0.1–0.3 wt% rinse additive, foam collapse is influenced by sodium hydroxide concentration and the solubility of fatty acid soaps. Under these conditions, the hydrophobic silica component of a silicone defoamer can be wetted or desorbed from the oil–water interface, causing a decay in foam control. Field data for RH-9200 in a specific bottle-washing line is not available in public supplier literature; qualification should therefore include a caustic stability jar test at the operating temperature and 24 h observation against a control defoamer.
In textile jet dyeing and scouring, defoamer durability must be balanced against the risk of fabric spotting. Silicone defoamers are preferred for high-temperature jet dyeing because polyether defoamers can become foam stabilizers above their cloud point. A class-typical addition rate is 0.1–0.5 g/L in the dyebath, but the value for RH-9200 is product-specific and limited public data exist. Dispersion should be made with a 1:10 dilution before addition to the dye kier to avoid silicone oil agglomerates that can deposit on polyester or nylon fabric. Cleaning of fouled machine surfaces may require alkaline detergents or solvent-based systems; once silicone oil has polymerized or bound to hydrophobic residues, removal is difficult. The operational boundary is therefore narrow: a dose sufficient for foam knockdown can become a spotting defect if mixing is not maintained during addition.
In activated sludge aeration basins, silicone defoamer addition is most effective when foam is caused by surfactant loading or dispersed polymer rather than by filamentous organisms such as Microthrix parvicella. If a mixed liquor microscopic examination shows filament index above 5 on a 0–6 scale, defoamer alone will not correct the root cause and may hide the biological imbalance. The defoamer feed for RH-9200 in a municipal or industrial effluent plant is class-typically applied at 1–10 ppm on total flow, either continuously into the aeration basin effluent weir or by intermittent slug dosing into the mixed liquor channel. The lower limit of 1 ppm is set by the minimum dispersion volume available; the upper limit of 10 ppm is a conservative ceiling above which silicone oil may pass through secondary clarifiers and coat dissolved oxygen sensors or UV disinfection sleeves. A 24 h composite test using an automated sampler and a foam-height recorder operating to ASTM E2407 can determine the minimum effective dose, but the plant’s solids retention time and return activated sludge flow must be kept constant during the trial.
Because RH-9200 is an emulsion, it must be protected from freezing. Storage between +5 °C and +40 °C is class-typical; repeated freeze–thaw cycles above 3 cycles should trigger re-qualification. Do not store in direct sunlight or in carbon steel vessels with unlined interiors. If separated, reconstitution by gentle agitation is possible, but hard settling or gelling requires disposal. The product should not be blended with cationic coagulants or strongly anionic polymers prior to dilution; simultaneous addition into the same injection point can form precipitates. This incompatibility is due to charge destabilization of the emulsifier package, not the silicone oil itself.
Regulatory status for silicone defoamer emulsions is use-dependent. In paper and paperboard applications, 21 CFR 173.340 addresses defoaming agents used in the manufacture of paper and paperboard; 21 CFR 176.210 is relevant for defoaming agents in coatings. Compliance with these provisions depends on the exact silicone identity, the use level, and the intended food type; a blanket clearance cannot be assigned without the manufacturer’s regulatory certificate. Under European Union regulations, a silicone defoamer placed on the market is subject to REACH registration; since RH-9200 is a mixture, the hazard classification follows the emulsifier and siloxane components under EC 1272/2008. Residual octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane can be present in low parts-per-million quantities; the supplier’s REACH Annex XVII statement should be reviewed where effluent is discharged to a receiving waterbody.
Material compatibility of the undiluted emulsion and diluted feed solution should be confirmed by immersion testing to ASTM D471 if elastomeric seals or diaphragms are employed. EPDM and PTFE are generally ranked as suitable for silicone emulsions; nitrile rubber may swell depending on the emulsifier package. The product should not be combined with amine-based additives or strongly cationic fixatives in concentrate form, because such combinations can collapse the emulsion and produce stringy residues. Do not use compressed air sparging for reconstitution; low-shear propeller agitation at 30–60 rpm is adequate.
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