Section
| HS Code | 910576 |
| Product Name | KM-90 Paint-Specific Silicone Antifoam Emulsion |
| Appearance | milky white homogeneous liquid |
| Chemical Type | polydimethylsiloxane emulsion |
| Active Silicone Content | 30% |
| Viscosity At 25 C | 1000 mPa·s |
| Ph At 25 C | 7.0 |
| Specific Gravity At 25 C | 1.00 |
| Ionic Character | nonionic |
| Water Dispersibility | easily dispersible in water |
| Recommended Addition Rate | 0.1% to 0.5% of total paint formulation |
| Storage Temperature | 5°C to 35°C |
| Shelf Life | 6 months in original sealed container |
As an accredited KM-90 Paint-Specific Silicone Antifoam Emulsion factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | KM-90 Paint-Specific Silicone Antifoam Emulsion is supplied in a 25 kg sealed plastic drum with safety-labeled packaging. |
| Container Loading (20′ FCL) | Loading KM-90 antifoam emulsion into a 20-foot FCL, using drums/IBCs, secured and blocked for safe transit. |
| Shipping | KM-90 Paint-Specific Silicone Antifoam Emulsion ships in sealed, labeled containers (pails or drums) to prevent leaks. Non-hazardous, it travels via standard ground freight. Keep upright, protect from freezing and extreme heat. Ensure compliant documentation and sturdy palletization for safe, efficient delivery. |
| Storage | Store KM-90 Paint-Specific Silicone Antifoam Emulsion in its original, tightly sealed container in a cool, dry, well-ventilated area away from direct sunlight, heat, and incompatible materials. Avoid freezing and temperatures above 40°C. Keep container upright to prevent leakage. Under proper conditions, shelf life is typically 12 months from manufacture date. |
| Shelf Life | Store unopened in original container; shelf life is 12 months from date of manufacture when kept from freezing. |
Formulated architectural flat and low-sheen latex paints with pigment volume concentration between 45% and 75% entrain air during high-speed Cowles dispersion of rutile TiO₂ and calcined clay or calcium carbonate extenders. In production-scale dissolvers with a tip speed of 18–25 m/s, surfactant-stabilized acrylic or vinyl-acrylic binders generate microfoam that is not released during the letdown phase. KM-90 is incorporated at 0.1–0.3 wt% of total batch, with the first 60% of the charge introduced before pigment dispersion and the remaining 40% added after thickener dilution. The defoamer droplets must survive a Cowles blade shear field of 10–15 kW per 1,000 kg while still spreading at the air–liquid interface in the final can. Incompatibility appears as surface seediness, floating silicones, or loss of intercoat adhesion. Roller application testing per ASTM D4707 shows that overdosage above 0.5 wt% increases spatter and reduces flow, while underdosing below 0.05 wt% leaves pinholing in drawdowns assessed under ASTM D4062. Density recovery after 5 min at 3,000 rpm in a laboratory disc disperser is measured against ISO 2811-1; complete deaeration typically returns density from 1.19 g/cm³ to 1.30 g/cm³ in a 55-PVC formulation, but published data for this specific formulation pattern is limited. The emulsion must be post-added at a mixer speed below 8 m/s if the cellulosic associative thickener package uses hydroxyethyl cellulose above 0.5 phr, because prolonged high shear can strip the silicone from the carrier and form oily slicks on the paint surface.
High-gloss waterborne alkyd and acrylic trim enamels with glass transition temperatures between 20°C and 45°C are formulated at low pigment volume concentration below 25%. Under high-speed dispersion at blade tip speeds above 20 m/s, the lower viscosity of the binder phase permits air bubbles to rise but also stabilizes smaller bubbles through surface-active coalescents. The silicone antifoam emulsion is post-added at 0.05–0.2 wt% after the grind has cooled below 40°C. This addition point prevents destabilization of the pre-composite surfactant layer around polymer particles. The critical performance parameter in trim enamels is not the initial air release but the long-term gloss retention measured under ASTM D523 at 20° and 60°. Silicone droplets larger than 20 µm can create cratering on brush-out panels; therefore the emulsion should be screened using a Hegman grind gauge per ASTM D1210 and a 100 µm wet drawdown film. If the Hegman reading drops from 6 to 4, the dosage is reduced by 0.02 wt% increments. The defoamer must not depress gloss below 80 GU at 60° in a 100 µm applicator drawdown. Production batches of 1,000–3,000 kg add the emulsion through a dosing lance under low shear at 3–5 m/s to avoid shear-induced droplet coalescence. For batch-to-batch consistency, the silicone content is verified by Fourier-transform infrared spectroscopy after extraction in xylene; a standard addition of 0.1 wt% typically leaves a silicone residue below 0.02% in the dry film, which is sufficient to resist foam but not high enough to affect recoatability after 16 h at 23°C and 50% relative humidity.
In water-dilutable two-component polyurethane clearcoats with a solids content of 35–55% and an NCO:OH ratio between 1.0 and 1.2, foam is less visible than in latex paints but remains a defect source during spray application and flash-off. The silicone antifoam emulsion is added at 0.05–0.1 wt% based on total varnish, either before the rheology modifiers are dispersed or after final viscosity adjustment under a dissolver speed below 5 m/s. The main failure mode is cratering caused by surface tension differentials exceeding 2 mN/m between droplets and binder matrix. A dosage above 0.2 wt% in a clearcoat sprayed at 25–30 µm dry film thickness can produce visible craters in a cross-hatch panel under DIN EN ISO 2409. Addition rate is therefore bracketed in 0.02 wt% steps, with each panel evaluated for long-wave and short-wave values on a WaveScan DOI instrument; acceptance is typically LW < 10 and WI < 15 for a Class A finish. The silicone emulsion must remain stable in the presence of co-solvents such as propylene glycol n-butyl ether and dipropylene glycol dimethyl ether. Long-term storage at 40°C for 28 days should not produce visible oiling on the clearcoat surface. Published data for this specific additive in water-dilutable 2K polyurethane is limited, so plant validation is required before production release.
Waterborne flexographic inks on corona-treated polyethylene film printed at line speeds of 200–400 m/min accumulate microfoam in enclosed doctor blade chambers, where foam alters ink transfer and causes cavitation in anilox cells. The silicone antifoam emulsion is dosed into the press-ready ink at 0.1–0.3 wt% and must not reduce surface tension below 30 mN/m, because lower surface tension causes white-out and poor wetting on low-energy substrates. Foam control in press-side dilutions is assessed by circulating the ink through a gear pump at 1,000 rpm and measuring the time for foam to collapse to 10% of the initial volume; a well-adjusted dose typically collapses within 60 s. The emulsion must be compatible with acrylic solution resins, styrene-acrylic emulsions, and polyethylene wax dispersions. Overdosage above 0.5 wt% is visible as fish-eyes in a 6 g/m² drawdown over corona-treated BOPP, assessed under a fluorescent UV lamp at 20× magnification. For ISO 12647-2 compliant process color inks, the defoamer cannot shift viscosity by more than 10% as measured by a Brookfield viscometer at 100 rpm under ISO 12058-1. In high-speed gravure printing at 300–500 m/min, the emulsion should be added only after the final filtration stage to avoid retention on depth filters rated below 5 µm. Silicon-based antifoam can accumulate on ceramic anilox rollers if the emulsion droplet size exceeds the cell opening; therefore the product should be monitored using a laser diffraction instrument per ISO 13320.
| Test parameter | Standard designation | Typical acceptance window |
| Stormer viscosity change | ASTM D562 | ±5 KU from control |
| Gloss retention at 60° | ASTM D523 | ≥80 GU |
| Flow/leveling drawdown | ASTM D4062 | No fisheyes at 100 µm |
| Roller spatter resistance | ASTM D4707 | ≤3 on comparative scale |
| Density deaeration | ISO 2811-1 | Recovery to ±0.03 g/cm³ of theoretical |
| Salt spray resistance | ASTM B117 | No pinholes after 500 h |
| Freeze-thaw stability | ASTM D2243 | No silicone separation after 3 cycles |
| Fineness of grind | ASTM D1210 | Hegman ≥5 |
On continuous coil coating lines applying waterborne polyester-melamine primers to hot-dip galvanized steel at line speeds of 60–120 m/min, reverse-roll coaters deposit wet films of 25–50 µm. Under the high shear rate of approximately 10⁴ s⁻¹ in the roll nip, air is drawn into the coating by the rotating applicator roll and trapped before the curing oven. The emulsion is added to the waterborne primer at 0.1–0.25 wt% and is post-added after the pigment grind, because the first stage of coil coating dispersion is conducted in a horizontal bead mill with zirconia grinding media of 1.2–1.6 mm diameter. Foam left in the film at the oven entrance expands during the 40–60 s cure at a peak metal temperature of 232°C, forming pinholes that reduce the corrosion resistance of the finished coil. Salt spray resistance is evaluated under ASTM B117 for 500–1,000 h; pinholes are detected with a low-voltage holiday detector after reverse impact testing per ASTM D4145. The emulsion should not contain alkylphenol ethoxylates if the coil coating must meet the European Ecolabel criteria for indoor and outdoor paints and varnishes. Compatibility is confirmed using a Q-panel drawdown after 24 h at 25°C; separation of silicone on the surface is a rejection criterion. Because coil coating lines recover excess coating from the pan, the defoamer must resist shear degradation during recirculation at flow rates up to 50 L/min through diaphragm pumps. A rise in foam after 2 h of recirculation indicates that the silicone droplets have been stripped from the aqueous carrier and that the emulsion is not suitable for the return-loop configuration.
High-viscosity waterborne elastomeric acrylic coatings with a solids content of 55–68% and a Stormer viscosity between 90 KU and 120 KU are applied by airless spray units operating at 1,900–2,500 psi. The spray pump itself can generate foam in the hose line if the packing is worn, but most air is entrained during batch mixing of acrylic latex and calcium carbonate filler. KM-90 is added at 0.15–0.35 wt% and is split between the pigment dispersion and the final letdown to prevent foam from being locked into the high-viscosity matrix. In production batches with a fill volume of 1,000 gal, the first addition is made after 15–20 min of high-shear Cowles dispersion, and the second is made after the hydroxyethyl cellulose thickener has fully hydrated. A density check per ISO 2811-1 is run before packaging; a density loss of more than 0.05 g/cm³ from the theoretical value indicates incomplete deaeration. Wet film porosity after application is evaluated by applying a 500 µm drawdown on release paper and examining pinholes after 24 h at 23°C and 50% RH. The emulsion must not destabilize in the presence of zinc oxide or barium metaborate, which are common mildewcides in roof coatings. If the coating is intended for potable water tank linings, the antifoam dosage must be reviewed against NSF/ANSI 61 requirements. On roof surfaces where aggregate is broadcast into the wet coating, foam retention at the interface can reduce aggregate adhesion; therefore the defoamer is added with slow stirring at 2–4 m/s for 10–15 min before aggregate application.
Waterborne pigment dispersions for point-of-sale tinting systems are formulated with 30–70% pigment loading and high levels of nonionic and anionic wetting agents. These dispersions are dosed through automated tinting machines into base paints, where foam generated during the dispensing stroke can alter the final color strength. The silicone antifoam emulsion is incorporated at 0.1–0.3 wt% of the colorant, but it must be screened for tint strength retention after storage at 50°C for 14 days; the white reduction should remain within a Delta E* of 0.5 compared to the control under ISO 11664-4. The emulsion must not reduce compatibility with ethylene glycol and glycerin humectants during cyclic freeze-thaw testing per ASTM D2243. Silicone separation is checked after 3 cycles between -5°C and 40°C. In high-volume dispenser systems with 10–250 mL piston strokes, microfoam in the colorant can cause volumetric dosing errors above 0.1 mL per stroke; the defoamer therefore must collapse foam within 5 min after the colorant returns to rest. If the colorant contains carbon black or organic pigments with high surface area, the emulsion may compete with dispersant adsorption sites and should be evaluated using a tinted drawdown over white and black opacity charts. Any loss of color acceptance in a latex base paint indicates that the defoamer concentration is above the wetting agent capacity of the system and must be reduced to the lowest level that still controls dispenser foam.
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KM-90 Paint-Specific Silicone Antifoam Emulsion is a non-ionic, water-dilutable silicone defoamer developed for aqueous architectural coatings and water-reducible industrial finishes. The active phase comprises high-viscosity polydimethylsiloxane fluid combined with hydrophobized fumed silica, emulsified in water with non-ionic surfactants. The product is introduced into the coating during let-down or post-milling to control microfoam generated by high-shear dispersion, air entrapment during mixing, and surfactant-stabilized foam in low-VOC acrylic and styrene-acrylic binders. The emulsion suppresses foam through a spreading-bridging mechanism: the silicone phase develops a positive spreading coefficient against the aqueous paint surface and destabilizes foam lamellae by local thinning and dewetting. For this product class, silicone active content is typically in the 10–30 wt% range, with the balance consisting of water, emulsifier, and rheology modifier. Published data for this specific model is limited; the values cited below are representative ranges from commercial silicone antifoam emulsions of similar composition and should be verified against the lot-specific certificate of analysis and technical data sheet.
Typical physical properties reported for this class include density 0.98–1.02 g/cm³ at 20 °C by ISO 2811-1, pH 6.5–8.5 as an aqueous dispersion, Brookfield viscosity 200–1500 mPa·s at 25 °C using a Brookfield LV spindle at 60 rpm per ASTM D2196-20, and non-volatile content 20–35% by ISO 3251:2019. The median particle size of the dispersed silicone phase is typically 5–50 µm as measured by laser diffraction per ISO 13320-1:2020; emulsions in the lower end of this range tend to reduce cratering but may show shorter defoaming persistence in circulating lines, whereas larger droplets provide longer-lived foam control at increased surface-defect risk. Storage stability is normally limited to 6–12 months at 5–35 °C in sealed containers; freezing below 0 °C can destabilize the emulsion irreversibly.
The product is typically evaluated at 0.05–0.5 wt% based on total formulation weight. In high-PVC interior matte paints containing 60–75 PVC, foam control often requires the higher end of the range because of air entrapment in coarse extenders. In clear wood coatings or high-gloss acrylic topcoats, doses above 0.2 wt% may produce visible surface defects under ASTM D523-14 60° gloss measurement. The optimum dose is determined by compounding a ladder series at 0.05 wt%, 0.10 wt%, 0.20 wt%, and 0.35 wt%, then comparing foam height after high-shear mixing using ASTM E2407-04(2015).
The functional distinction is primarily surface activity, particle size retention, and compatibility under film formation conditions. Mineral oil defoamers, often containing hydrophobic silica or wax particles, rely on droplet penetration of foam lamellae; they are inexpensive and low-risk for gloss retention but have limited persistence in low-VOC systems because their oil phase can be solubilized by coalescents and high-HLB surfactants. Polyether-modified siloxane defoamers offer improved compatibility and are often used in clear coatings, but their defoaming strength at equal active content can be lower than a high-molecular-weight polydimethylsiloxane emulsion. KM-90 belongs to a paint-specific class in which the silicone fluid molecular weight and the hydrophobized silica level are adjusted to maintain knockdown in surfactant-stabilized latex without excessive cratering. This balance is measurable: the silicone phase surface tension is approximately 20–22 mN/m at 25 °C, while typical aqueous paint surface tension is 30–40 mN/m, producing a positive spreading coefficient. The comparative table below summarizes typical industrial experience for common defoamer chemistries.
| Defoamer chemistry | Typical use level (wt% total | Knockdown speed | Persistence under high-shear recirculation | Cratering tendency at 60° gloss | Primary limitation |
|---|---|---|---|---|---|
| KM-90 silicone emulsion | 0.05–0.35 | Fast | Moderate-high | Low-moderate | Over-dosage can create fisheyes; freeze-thaw sensitivity |
| Mineral oil with hydrophobic silica | 0.1–0.5 | Moderate | Low | Low | Loss of persistence with high-HLB surfactants and coalescents |
| Polyether-modified siloxane | 0.1–0.6 | Moderate | Moderate | Very low | Higher cost; may soften film in high dosage |
| Hydrophobic silica in mineral oil | 0.1–0.4 | Moderate-slow | Low-moderate | Low | Settling and possible tint strength loss |
The selection between these chemistries cannot be made solely from defoaming efficiency tests. In high-gloss waterborne enamels, a polyether siloxane may be preferred solely because it reduces surface defects; in high-PVC interior paints, a mineral oil may pass, but KM-90 can be used at 0.10–0.20 wt% when microfoam persists after tinting with colorants containing high-HLB surfactants. Field observations on high-speed dispersers of 15 kW power with 500 kg batch sizes indicate that mineral oil defoamers can lose knockdown after the first 4–6 h of circulation, whereas silicone emulsions of this class retain measurable defoaming through 8–12 h of low-shear stirring.
On production lines, KM-90 is most often added at the let-down stage after pigment dispersion has cooled below 40 °C. Addition to a high-speed disperser equipped with a 45° cowles blade at 5–10 m/s tip speed for 10–15 min produces homogeneous incorporation without excessive emulsion breakage. The addition point should avoid areas of intense shear near the shaft if craters are observed; a post-add tank with propeller agitation at 50–150 rpm may be used for sensitive clears. In long-oil alkyd emulsions or systems with high solvent content, pre-dilution with water at 1:1 to 1:3 by volume reduces localized droplet coalescence. The product should not be added before pH adjustment in acid-catalyzed coatings if the coating pH falls below 4.0, because emulsion stability can decline and free silicone may accumulate at the surface.
The point of addition changes particle size distribution, foam-control longevity, and surface defect profile. In grinding, the emulsion droplets are exposed to high shear and pigment–binder interactions for 20–60 min at temperatures that can exceed 50 °C in a horizontal bead mill. Mechanical energy can reduce the median silicone droplet diameter to <10 µm, improving compatibility and reducing visible fisheyes, but this also increases interfacial area and may accelerate adsorption onto pigment surfaces, depleting the defoamer available for foam control. In one production-scale observation with a 75 L horizontal bead mill operating at 12 m/s rotor-tip speed, addition before grinding required 0.15–0.20 wt% to achieve the same foam knockdown as 0.10 wt% added at let-down. The trade-off is not linear; in high-PVC systems with 15–20% TiO₂ and 25–35% extender, grind-stage addition may be acceptable because surface defects are less visible. In clear or high-gloss systems, grind-stage addition can produce an increase in 20° haze if silicone droplets are not sufficiently sheared.
Batch-to-batch variance on a 2,000 L let-down tank with bottom-entering agitator has been traced to the timing of addition relative to thickener hydration. If the defoamer is added after cellulose ether or associative thickener has fully built viscosity, dispersion is slower and defoamer droplets may remain localized, causing temporary cratering. A reproducible sequence is to add the defoamer before final rheology modifier addition, then mix under low shear for 10–20 min before viscosity build. When the process temperature exceeds 45 °C, non-ionic emulsifier cloud point effects can induce droplet coalescence; below 10 °C, viscosity may rise above 1500 mPa·s and complicate pumping. The preferred processing window is therefore 15–40 °C.
KM-90 is not universally inert. In acid-catalyzed coil coatings and acid-cured wood finishes where package pH is below 4.0, emulsion droplets may coalesce or cream, especially if solvent content exceeds 10–15 wt%. Strong acids can protonate the emulsifier layer, reducing electrostatic repulsion and allowing silicone to separate as an oily top layer. In 2K waterborne polyurethanes, the defoamer should be evaluated for intercoat adhesion; a cross-cut adhesion test per ASTM D3359-23 on a two-coat system is recommended because silicone migration to the coating surface can reduce the surface energy of the first coat and interfere with re-coating. Doses above 0.3 wt% in a 2K polyurethane clearcoat have been associated with cratering and loss of distinctness of image, although 60° gloss under ASTM D523-14 may remain within specification. In high-solids epoxy primers, the product can be used at 0.1–0.2 wt% to break foam generated during mixing of amine hardener with epoxy emulsion, but the formulator should confirm that the hardener does not contain high levels of reactive silanes that compete with the antifoam droplet interface.
The product should be excluded from formulations containing cationic wetting agents or strongly basic systems above pH 9.5, because the non-ionic emulsion can invert or separate. Storage tanks should be made of 316L stainless steel or polyethylene; carbon steel is acceptable only for short-term hold if the tank is free of rust. Recirculation lines should operate at low shear; centrifugal pumps with narrow clearances can mechanically break the emulsion and reduce defoaming persistence.
| Standard or regulation | Relevant parameter | Application boundary |
|---|---|---|
| EU REACH (EC) No 1907/2006 | Registration and SVHC content | Product-specific safety data sheet required; SVHC below 0.1 wt% per substance |
| EU RoHS 2011/65/EU | Restricted heavy metals | Raw materials checked for lead, cadmium, mercury, hexavalent chromium |
| US FDA 21 CFR 175.300 | Incidental food-contact coatings | Formulation-specific migration testing required before use in food-contact applications |
| ASTM E2407-04(2015) | Defoaming effectiveness | Foam knockdown comparison in aqueous media |
| ISO 2811-1 | Density | 0.98–1.02 g/cm³ at 20 °C |
| ISO 13320-1:2020 | Particle size distribution | Median droplet size 5–50 µm |
Thermal aging often separates defoaming performance from compatibility performance. A sample stored at 50 °C for 14 days may retain foam knockdown in the liquid paint because the silicone droplets remain effective, yet the same aged sample can show increased cratering due to partial emulsion coalescence or migration of silicone to the can surface. Conversely, an emulsion that separates into a cream layer under storage may appear to fail but can be reincorporated with gentle agitation and still perform. Routine incoming inspection should therefore include not only liquid-phase appearance but also particle size distribution after 1 min agitation and a drawdown test for surface defects. The drawdown test should be performed with a wire-wound bar at 75 µm wet film thickness on black glass, followed by drying at 23 °C and 50% RH for 24 h. Surface defects are assessed by visual inspection under 100 lux illumination; crater counts above 5 per 100 cm² typically indicate incompatibility or over-dosage.
In high-humidity exterior latex systems applied by airless sprayer, foam-related pinholes can appear on hot, humid days because the coating film skins over rapidly while air bubbles remain trapped. KM-90 can be evaluated at 0.15–0.25 wt% in these formulations. The product should be incorporated after the final grind but before the adjustment of Krebs viscosity to 90–110 KU per ASTM D562-10(2018). In a spray application through a 0.015 in tip at 1500 psi, foam-related pinholes are reduced when the defoamer is combined with a hydrophobic solids level of 2–5% in the dry film; however, the exact level must be verified by spray trials because over-deaeration can lead to sagging on vertical surfaces when the wet film thickness exceeds 100 µm. The product’s contribution to sag resistance is indirect and should be assessed with ASTM D4400-18.
