Section
| HS Code | 648831 |
| Producttype | Silicone antifoam emulsion |
| Appearance | White milky liquid |
| Ionictype | Nonionic |
| Activesiliconecontent | 30% |
| Totalsolidscontent | 33% |
| Viscosity | 100-500 mPa·s at 25°C |
| Ph | 6.0-8.0 at 25°C |
| Specificgravity | 0.98-1.02 at 25°C |
| Particlesize | 1-10 μm |
| Waterdispersibility | Fully disperses in cold and warm water |
| Foamsuppressionproperty | Suppresses foam formation and destroys existing foam in aqueous coating systems |
| Emulsifiertype | Nonionic surfactant system |
| Thermalstability | Stable under ambient coating application and curing conditions |
| Storagestability | Stable for 6 months in sealed original containers above 5°C |
As an accredited KM-75 Coating-Grade Silicone Antifoam Emulsion factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | KM-75 Coating-Grade Silicone Antifoam Emulsion is supplied in 25 kg pails or 200 kg drums, with secure lids for safe storage and handling. |
| Container Loading (20′ FCL) | KM-75 antifoam emulsion loaded as 20′ FCL, secured in drums/IBCs, stable product, safe container stowage for transit. |
| Shipping | KM-75 Coating-Grade Silicone Antifoam Emulsion ships in sealed drums or totes, protected from freezing and extreme heat to maintain stability. Not regulated as dangerous goods under standard transport rules. Ensure containers upright, secure against shifting, and store between 5–40°C. Delivery available via standard freight or expedited services depending on volume. |
| Storage | Store KM-75 in its original, tightly sealed container in a cool, dry, well-ventilated area away from direct sunlight, heat sources, and freezing temperatures. Recommended storage range is typically 5–35°C. Keep away from incompatible materials. Stir or gently agitate before use to ensure homogeneity. Follow manufacturer guidelines for shelf life. |
| Shelf Life | Shelf life is typically 12 months from manufacture when stored in original containers at recommended temperatures. |
In waterborne architectural latex paint manufacture, KM-75 Coating-Grade Silicone Antifoam Emulsion is positioned as a mill-base air-release agent where high pigment volume concentration produces microfoam that persists through letdown. The addition ratio is set at 0.15–0.35 wt% of total batch weight for standard interior and exterior formulations, but shifts to 0.30–0.50 wt% when PVC exceeds 70% because untreated pigment surfaces entrain air during high-speed dispersion. Production-scale batches on 10,000 L high-speed dispersers use a Cowles blade at 18–25 m/s tip speed for 15–25 min; KM-75 is introduced into the pigment slurry 5–10 mm from the blade periphery before associative polyurethane thickeners to avoid post-thickener viscosity swings. Finished coatings must conform to GB/T 9756-2018 scrub resistance indices, GB 18582-2020 VOC limits, and EU Ecolabel criteria 2014/312/EU for painted surfaces; air release is verified by density recovery per ISO 2811-1 after vacuum degassing. Addition above 0.60 wt% in silky-matte bases has been observed to reduce 85° gloss by more than 4 units and generate cratering on Leneta treated panels, so the operational boundary is fixed below this threshold. Terminal finished product types include interior matte emulsion wall paints and exterior elastomeric masonry coatings.
Water-reducible polyester/melamine coil coating formulations incorporate KM-75 at 0.05–0.25 wt% based on total wet paint, with the addition made after resin neutralization but before melamine crosslinker dispersion to minimize interference with substrate wetting on reverse-roll coaters. Production lines running at 120–180 m/min deposit wet films of 12–20 µm; air introduced through recirculation troughs becomes pinhole defects in the cured film unless the silicone antifoam emulsion maintains a deaeration rate compatible with fast flash-off. Compliance for food-contact can coatings requires that the finished system meets FDA 21 CFR 175.300 resinous and polymeric coatings clearance and EU Regulation (EC) No 1935/2004 overall migration limits; the emulsion must not contribute extractable silicones exceeding the applicable threshold after retort at 121°C for 30 min. Solvent resistance is evaluated per ASTM D5402-19 MEK double rubs, and dry adhesion after retort is checked per ASTM D3359 crosshatch tape pull. Above 0.30 wt%, surface tension reduction can lower intercoat adhesion in two-coat systems where a white basecoat is overprinted with a clear polyester topcoat; this is the principal incompatibility to control in coil lines operating at peak metal temperatures of 232–249°C. Terminal finished product types are food can interior clear lacquers and coil-coated aluminium roof and wall panels.
In waterborne flexographic and gravure ink production, KM-75 is added at 0.05–0.20 wt% of the finished ink or overprint varnish, and its defoaming performance is assessed after 5 min mixing at 3000 rpm on a laboratory dissolver. At these concentrations, the emulsion does not block ceramic anilox cells in 180 l/cm rolls with 20 µm cell depth; above 0.25 wt%, hydrophobic silicone particles larger than 25 µm can lodge in cell walls and produce print mottle. The production process includes dispersing acrylic pigment concentrates in deionized water at pH 8.0–9.0, adjusting viscosity to 30–60 s DIN 4 cup for flexo application, and depositing overprint varnish through a 60 l/cm anilox at 50–150 m/min on polyethylene-coated board. Compliance with the EuPIA Good Manufacturing Practice for printing inks and indirect food contact legislation requires confirmation that no silicone migration above applicable SMLs occurs under Regulation (EC) No 1935/2004; heat-seal exposure at 140°C for 1.5 s demands defoamer stability without forming volatile pinholes. Terminal finished product types are water-based flexographic inks for corrugated board and overprint varnishes for folding cartons. Published data for this specific configuration is limited above 0.25 wt%, and mill trials are required for anilox rolls finer than 200 l/cm.
Water-dispersible polyurethane/acrylic wood coating formulations use KM-75 at 0.10–0.40 wt% and apply it with air-assisted airless equipment at 80–120 bar through 0.28 mm nozzle tips; foam forms in the return line when drum pumps operate at 15 L/min and must be suppressed before the spray front reaches the workpiece. The antifoam emulsion is added after dispersion of matting silica but before associative thickener incorporation, because post-addition into thickened coating creates visible fisheyes in 80–120 µm wet films. At 0.40 wt%, the 60° gloss of a clear acrylic topcoat measured per ISO 2813 drops by less than 2 units, but above 0.60 wt% haze increases and intercoat adhesion after sanding may fail under 2 kg tape pull per ASTM D3359. Children's furniture lacquers must meet EN 71-3:2019+A1:2021 selected element migration limits, and one-pack waterborne wood coatings must comply with VOC limits under Directive 2004/42/EC Annex IIA categories for wood coatings. Terminal finished product types are waterborne furniture topcoats and joinery primers, typically produced in 500–2,000 kg batches. The emulsion destabilizes at pH >10, so it is not added directly to amine-neutralized side streams.
Corrosion-protective waterborne zinc-rich epoxy primers require defoaming without disrupting zinc particle suspension. KM-75 is added at 0.20–0.40 wt% in the resin phase before zinc dust incorporation; addition after zinc dust leads to localized air release in the high-density particulate phase and uneven film conductivity. Mixing proceeds in a planetary multi-shaft mixer at 600–900 rpm under vacuum of 0.08 MPa, where the silicone emulsion reduces air entrainment during 20 min of high-viscosity blending; at RH > 60%, zinc dust is predried to avoid moisture-induced gassing. The formulated primer must meet ISO 12944-5:2019 corrosion class C3 requirements for structural steel and, in China, GB/T 30790.5-2014 equivalent guidance; salt spray performance is assessed per ISO 9227 after 500 h. Direct combination with amine-based hardeners is avoided because the emulsion destabilizes at pH >10, and pre-drying of zinc dust at 60°C for 2 h is required when storage humidity exceeds 60%. Terminal finished product types are waterborne zinc-rich shop primers and maintenance epoxies for structural steel fabrication.
In direct-to-metal waterborne acrylic coatings, KM-75 is added at 0.10–0.30 wt% to the grind phase after organic zinc flash-rust inhibitors have dissolved; adding the defoamer before the inhibitor can hinder wetting of carbon steel coupons and reduce corrosion resistance measured by salt spray per ISO 9227. The coatings are produced in a high-speed dissolver at 25 m/s tip speed for 20 min, then filtered through a 60 µm basket before airless spray application at 30–50 bar with a 0.33 mm tip. Compliance targets include corrosion class C3 under ISO 12944-5:2019 and condensation resistance under ISO 6270, with surface preparation specified by ISO 8501-1 cleanliness grade Sa 2½ for steel substrates. Because direct-to-metal acrylics are applied in single-coat builds of 60–80 µm dry film, the defoamer must release microfoam before skinning occurs; above 0.35 wt%, cratering on untopcoated steel is observed in air-assisted airless trials. Published data for this specific configuration is limited, and formulation use above 0.30 wt% requires substrate-specific salt spray verification. Terminal finished product types are direct-to-metal acrylic primers and one-coat machinery enamel systems.
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KM-75 Coating-Grade Silicone Antifoam Emulsion is supplied as a water-dilutable, nonionic white emulsion containing 20% active polydimethylsiloxane by mass, hydrophobic fumed silica, and an alkoxylated emulsifier package. The model designation identifies a coating-grade emulsion intended for aqueous architectural, industrial, and ink formulations where mineral-oil carriers or high active-oil addition would compromise gloss, recoatability, or VOC compliance. Lot-release documentation for KM-75 lists the following specification profile.
| Parameter | Method | Typical release value |
|---|---|---|
| Appearance | Visual inspection | White opaque liquid |
| Non-volatile content | ISO 3251 | 20 ± 1% by mass |
| pH as supplied | ISO 976 | 6.5–8.0 |
| Density at 25 °C | ISO 2811-1 | 1.00–1.03 g/cm³ |
| Brookfield viscosity at 25 °C, spindle 3, 60 rpm | ISO 2555 | 200–1,000 mPa·s |
| Median particle size | ISO 13320 | 5–20 μm |
| VOC content | ISO 11890-2 | 0 g/L |
The stated values are release-control ranges, not absolute performance limits. In formulated waterborne coatings, KM-75 is typically introduced at 0.05–0.25 wt% of total batch weight. The lower boundary is sufficient for foam control in low-viscosity clearcoats and dilute printing inks; the upper boundary is required only for high-PVC filled systems or elastomeric roof coatings. At 0.30 wt% in a high-gloss acrylic enamel, a 2–4 unit reduction in 60° gloss under ISO 2813 is observable. This dosage window is not directly transferable across other defoamer chemistries because active content and carrier composition differ.
In high-PVC waterborne acrylic and styrene-acrylic interior coatings, air is entrained during pigment dispersion under a high-speed disperser operating at 12–18 m/s Cowles tip speed. The resulting batch density reduction of 0.02–0.05 g/cm³ against the theoretical formula cannot be corrected by low-shear propeller agitation alone. KM-75 functions by spreading at the air–water interface and allowing hydrophobic silica particles to bridge the bubble lamella, producing rapid coalescence at addition levels between 0.10 wt% and 0.20 wt%.
The most restrictive process condition is addition timing, not total dosage. If the full defoamer charge is added before the pigment-dispersion phase, the emulsion droplets are fractured by high-shear Cowles conditions and may fall to 1–3 μm median diameter. This reduces bridging effectiveness because the droplets become too fine to destabilize larger air cells. If the full charge is added after the final associative thickener dose, drainage to the air interface is restricted by the thickened aqueous phase, and foam knockdown under ASTM D3601 is incomplete. Plant-scale practice is to add 60–70% of the total required dose in letdown at 300–600 rpm after pigment grind, with the remainder added after the final viscosity adjustment. For a 600 kg batch at 0.15 wt%, the total KM-75 charge is 900 g.
Dilution immediately before addition is limited to cold water at 10–25 °C and ratios of 1:1 to 1:9. Water above 35 °C can destabilize the emulsifier layer and produce localized coagulum that appears as visible gel specks in the wet film. The diluted material should be added as a thin stream to the vortex over 5–10 min; a single-point dump addition is associated with temporary cratering in spray-applied topcoat systems because local defoamer concentration exceeds the critical film-dewetting threshold before distributive mixing is complete.
In controlled binder-only evaluations using a styrene-acrylic dispersion of 50% solids, the addition of 0.15 wt% KM-75 reduces foam volume under ASTM D3601 by more than 80% within 5 min when compared with an undosed control. The result is specific to shear history and binder emulsifier type; anionic phosphate-functional monomer residues in some binders can reduce defoamer persistence at 40 °C over 14 days.
In high-PVC contract matte finishes below 65% PVC, KM-75 may be raised to 0.35 wt% without crater formation when the product is added after grind and before the final high-viscosity HEC thickener letdown. Published data for this specific configuration is limited, and the higher dosage is not recommended for gloss enamels, clearcoats, or systems subsequently overcoated with solventborne polyurethane.
When KM-75 is introduced into a 1,000 L letdown vessel fitted with a 0.75 kW propeller agitator running at 250 rpm, the recommended addition is a diluted side stream added over 5–10 min. Transfer lines should use low-shear positive-displacement or diaphragm pumps instead of high-speed centrifugal recirculation. Repeated passage through a rotor-stator mixer operating above 5 m/s tip speed can shear the emulsion and reduce macroscopic foam knockdown. If final filtration is required after defoamer addition, a 250 μm bag filter is acceptable, while a 50 μm cartridge filter may remove active silica aggregates and shift the effective dose.
Storage in sealed HDPE totes or drums at 5–35 °C maintains release viscosity for 9 months from the production date. The emulsion is not freeze-thaw stable. Storage below 5 °C causes non-reversible phase separation, and freeze-thaw cycling from −5 °C to 25 °C can increase median particle size to 35–80 μm after 3 cycles. Open containers exposed to relative humidity above 80% can develop condensation at the product surface, causing local viscosity drift; open containers should be sealed immediately after dosing.
The primary differentiating parameter is not total added mass but active defoamer concentration and carrier fluid composition. Because KM-75 contains 20% active polydimethylsiloxane, a 0.15 wt% dose delivers 0.03 wt% active PDMS on total formulation. A 100% active mineral-oil defoamer used at the same total dose introduces 0.15 wt% active oil, which may reduce gloss, increase surface tack, and contribute to hydrocarbon extractables. A 20% active polyether emulsion used at 0.15 wt% supplies lower bridging efficiency in high-air-entrainment slurries and therefore requires higher total dosage to achieve comparable knockdown.
| Parameter | KM-75 | Mineral-oil defoamer | Polyether defoamer |
|---|---|---|---|
| Active carrier | Water | Mineral oil or ester | Water or polyglycol |
| Active content | 20% | 100% | 20–100% |
| Typical addition in waterborne acrylics | 0.05–0.25 wt% | 0.10–0.50 wt% | 0.20–1.00 wt% |
| VOC contribution by ISO 11890-2 | 0 g/L | 25–45 g/L | 0–10 g/L |
| Cratering threshold in high-gloss enamel | 0.5 wt% | 0.3 wt% | 1.0 wt% |
| High-shear rotor-stator tolerance | Avoid above 5 m/s tip speed | Tolerant at 10 m/s tip speed | Tolerant at 10 m/s tip speed |
Mineral-oil defoamers remain preferable in some low-PVC alkyd spray enamels because they do not introduce an aqueous carrier into a solventborne system. KM-75 is not recommended for solventborne formulations because the water phase can phase-separate and produce film defects. Polyether defoamers are commonly preferred in clear topcoats where silicone-induced surface roughness must be minimized, although their efficiency in high-filler slurries is lower per unit active mass. KM-75 occupies an intermediate position: it avoids mineral-oil VOC and yellowing while requiring tighter dosage control in high-gloss clear films because of silicone surface activity.
At pH values below 6.0, the alkoxylated emulsifier system of KM-75 loses effective stabilization, and visual creaming may appear within 72 h at 40 °C. The product should not be premixed with quaternary ammonium biocides, strongly cationic wetting agents, or aluminum-based flocculants. Such combinations can produce gel particles greater than 100 μm that block spray filters and create visible defects on drawdown cards assessed under ISO 1524 grindometry. In UV-cured clearcoats and solventborne polyurethane topcoats, even 0.1 wt% KM-75 can reduce intercoat adhesion under cross-cut tape testing per ISO 2409; recoatability must be confirmed on primed panels before line use. The product is not intended for use below 5 °C storage or in formulations where the final coating will be exposed to continuous immersion in water above 60 °C, because prolonged wet heat can reduce defoamer persistence and allow post-application foam formation in recirculating finish tanks.
