Section
| HS Code | 634872 |
| Product Type | EO/PO block polyether defoamer |
| Chemical Composition | Ethylene oxide / propylene oxide block copolymer |
| Physical State | Liquid at room temperature |
| Appearance | Colorless to pale yellow transparent liquid |
| Active Content | 99% |
| Viscosity At 25 C | 400-800 mPa·s |
| Cloud Point 1 Aqueous Solution | 32-38°C |
| Pour Point | -20°C |
| Ph 1 Aqueous Solution | 5.0-7.0 |
| Water Solubility | Soluble in water at temperatures below cloud point |
| Hlb Value | 7 |
| Defoaming Performance | Efficient foam suppression and foam elimination |
As an accredited L62 EO/PO Block Polyether Defoamer factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | L62 EO/PO Block Polyether Defoamer is packaged in sealed 25 kg plastic drums, ensuring safe transport, stability, and easy handling. |
| Container Loading (20′ FCL) | 20′ FCL: 20-foot full container load of L62 EO/PO block polyether defoamer, safely packed in drums for export. |
| Shipping | L62 EO/PO Block Polyether Defoamer ships as a non-hazardous liquid in sealed drums, IBCs, or bulk containers. Keep containers upright, dry, and away from extreme heat, direct sunlight, and incompatible oxidizers. Ensure adequate ventilation and secure load to prevent leakage during transit. |
| Storage | Store L62 EO/PO Block Polyether Defoamer in a tightly sealed container in a cool, dry, well-ventilated area. Keep away from direct sunlight, heat sources, and incompatible chemicals. Recommended storage temperature is 5–40°C. Avoid prolonged exposure to moisture. Under proper conditions, the product remains stable for at least 12 months. |
| Shelf Life | Shelf life: 12 months when stored in original sealed containers, kept dry, cool, and away from direct sunlight. |
In submerged aerobic cultivation of filamentous fungi for industrial enzyme production, rising airlift and mechanical agitation generate protein-stabilized foam that can reduce working volume to 60–70 °C of nominal capacity in unprotected 20 m³ stirred-tank reactors. L62, a difunctional EO/PO block polyether with a nominal average molecular weight of 2500 g/mol and an EO content of approximately 20 wt%, is metered into the headspace or feed line at 0.05–0.5 g/L total batch volume. Below its cloud point of 32 °C in 1 wt% aqueous solution the molecule exists as a water-soluble micellar species; at typical cultivation temperatures of 34–37 °C the block copolymer undergoes phase separation into microdroplets with low dynamic surface tension. These droplets enter the foam lamellae and displace adsorbed protein at the air-liquid interface, causing film thinning and coalescence. Foam height in a 5-L stirred-tank bioreactor with two Rushton impellers, 1.5 vvm aeration, and 1200 rpm can be maintained below 20 mm when L62 is added incrementally at 0.1 g/L, based on conductivity probe thresholds; published data for larger-scale production configurations remains limited, and initial dosage should be established in side-stream foam-cell tests according to ASTM E2407-04. In actual broth, dissolved salts and organic acids depress the cloud point by 5–10 °C, which favors formation of defoaming droplets at lower temperatures. L62 is not recommended for steam-in-place sterilization as a concentrated aqueous solution above cloud point because thermal phase separation may leave polymer-rich deposits in transfer lines. If aseptic addition is required, the defoamer is autoclaved neat in a pressure-rated vessel and transferred through an aseptic barrier system, but filterability through 0.2 µm cartridges is poor above 25 °C due to increasing viscosity. In fed-batch processes, the oxygen transfer coefficient kLa measured by sulfite oxidation should be monitored after each bolus addition because overdosing can lower kLa by more than 10% at concentrations above 0.8 g/L, an operational boundary that varies with broth viscosity, protein load, and agitator power input.
In central filtration systems serving multi-spindle CNC machining cells, water-diluted semisynthetic metalworking fluids are circulated at 20–70 L/min and sprayed through nozzles at 10–80 bar. This high-shear return flow entrains air and creates microfoam that reduces heat transfer at the cutting edge and causes sump level fluctuations. L62 is typically post-added to the concentrate at 0.1–0.5 wt% before water dilution to 5–8 vol%; because the block copolymer has an inverse solubility profile, the portion in the hot cutting zone exceeds its cloud point of 32 °C and concentrates at the air-liquid interface, while the cooled sump phase retains sufficient water solubility to avoid oil separation. Foam tendency of the diluted fluid can be evaluated with a blender test in accordance with ASTM D3601-88(2014), where foam volume after 30 s of high-speed blending and after 5 min settling should not exceed 50 mL and 10 mL respectively for semi-synthetic formulations containing L62 at 0.3 wt%. Emulsion stability under centrifugation at 1500 × g for 15 min should remain within ±2 vol% free oil, because L62 may lower the cloud point of the anionic emulsifier package and reduce reserve alkalinity if overdosed. The product is compatible with petroleum sulfonates, tall oil fatty acid soaps, and boric ester EP additives, but is not recommended in concentrates containing high levels of quaternary ammonium biocides or cationic polymeric flocculants. Observed failure mode on production lines is the formation of tacky residues on band filters and oil skimmers when tramp oil surpasses 15% of sump volume and L62 dosage is maintained above 0.4 wt%. In such conditions, the defoamer can act as a coupling agent between mineral oil and metal fines, producing a viscous paste that blinds filter media and increases carry-off on machined parts.
After the redox finishing stage in batch emulsion polymerization of vinyl acetate-ethylene copolymers, residual monomer stripping under vacuum at 60–70 °C generates a dense foam head that can carry latex particles into overhead condensers and cause polymer buildup. L62 is introduced at 0.05–0.2 wt% based on wet latex solids after the redox pair has been consumed, preventing monomer carryover without causing creaming or grit formation. Jarred dispersion seed stability tests using a Hegman gauge and 25 µm screen filtration indicate that L62 at 0.2 wt% does not increase coagulum above 0.02 wt% in carboxylated styrene-butadiene latex, whereas mineral oil defoamers at equal active concentration can raise filter residue by 0.1–0.3 wt% due to hydrophobic particle bridging. Surface tension depression is moderate, typically 38–40 mN/m at 0.1 wt% in deionized water at 25 °C, which is sufficient for wetting in knife coating but low enough to avoid foam restabilization in subsequent high-shear coating. Because the cloud point of L62 lies near 32 °C, storage of compounded latex below 25 °C is recommended; at chilled temperatures below 10 °C the defoamer may partition into the serum and reduce long-term shelf stability after repeated freeze-thaw cycles. The addition point should be located downstream of the seed particle growth stage and not into the monomer pre-emulsion, where early incorporation can alter particle nucleation kinetics and increase the polydispersity index of the final dispersion as measured by dynamic light scattering.
Recirculated coating color on a blade coater operating at 1500 m/min entrains air in the pigment/polymer binder phase when calcium carbonate slurries release carbon dioxide through acid-base reactions with cationic retention aids. L62 at 0.05–0.1 wt% based on dry pigment is added to the letdown tank after starch cooking and before the machine chest, not during high-shear dispersion of calcium carbonate because the high temperature and pH above 9 can reduce defoaming efficiency by more than 20% when held for over 6 h. Foam removal in the machine tank is measured by ultrasonic foam sensors controlling a defoamer metering pump; injection is split between the screen accepts and the coating color supply tank to prevent air-bound pumps. A typical process limit is a coating color density of 1.20–1.30 g/cm³ with a pH of 8.5–9.5 and a Brookfield viscosity of 1000–1500 mPa·s at 100 rpm spindle 4. At these conditions L62 does not require pre-dilution when the coating color temperature is above 20 °C. However, in starch-only surface sizing with oxidized starch at 60–70 °C, L62 is less effective because the high-temperature starch film stabilizes foam and the defoamer remains water-soluble below its cloud point only in cooled short loops. The product is therefore limited to polymer-bound coating colors rather than pure starch size presses, and should not be added directly to cationic silica sol retention systems due to the risk of local flocculation and blade streak formation.
Polyester rope dyeing in a 1500 kg jet machine with nozzle pressure of 2.5 bar and liquor circulation rates around 4–6 cycles per minute generates shear foam that can interrupt pump suction and create dye streaks. L62 is dosed into the scouring bath at 0.1–0.2 g/L before dye addition, not directly with disperse dye dispersants, because the block copolymer can wet out the disperse dye particles and modify their particle size distribution if pre-mixed in the dye tank at concentrations above 0.3 g/L. At the process temperature of 130 °C the defoamer is above its cloud point and exists as dispersed droplets, which is effective for air removal during pressurization. Upon cooling below 32 °C it returns to solution and is largely removed in overflow rinsing. Residual L62 on polyester fabric can be assessed by extraction with methanol and cobalt thiocyanate colorimetric detection; typical residual values below 0.05 wt% on dry fabric are reported by dyehouse laboratories when a 1:10 bath ratio and two cold rinse cycles are used. The product is not suitable for silicone-softener combination baths due to potential oiling off, and is not recommended as an in-bath defoamer for acid dyeing of nylon at pH below 3.5 because cloud point depression by acid may produce excessive water insolubility and deposit on fabric edges. In high-pressure beam dyeing of polyester yarn packages, L62 should be added only to the expansion tank after the package has been fully saturated, otherwise initial liquor bypass through low-density packages can leave polymer-rich streaks that appear as light spots after reduction clearing.
Cooling tower basins and municipal secondary clarifiers develop foam stabilized by extracellular polymeric substances from activated sludge flocs. L62 can be dosed at 5–20 mg/L into the basin return channel, with point-feed injection through a quill upstream of the recirculating pump to maximize dispersion across the falling water film. Unlike silicone-based antifoams, L62 does not deposit on conductivity sensors or chlorine residual analyzers in the blowdown line. Field measurements with a portable foam rise column show foam collapse times of less than 10 s at 10 mg/L in synthetic secondary effluent with 500 mg/L mixed liquor suspended solids. The product is biodegradable under OECD 301F at 28-day incubation but not classified as readily biodegradable if the pass level is not reached in the specific formulation. L62 should be stored in closed vessels at 1–40 °C because prolonged exposure to air above 50 °C increases peroxide formation and lowers pour point stability. Field calibration should be repeated after any change in polymer dose or sludge age because soluble extracellular polymeric substances alter the defoamer demand nonlinearly.
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L62 EO/PO block polyether defoamer is a liquid non-silicone block copolymer based on sequential ethylene oxide and propylene oxide addition. The substance is identified by CAS 9003-11-6 and corresponds to the poloxamer commonly listed as Poloxamer 182. At 25 °C it is a clear to slightly hazy liquid with a viscosity of approximately 400 mPa·s under ISO 2555 rotational viscometry. Manufacturer technical data place the average molar mass near 2,500 g/mol and the hydrophilic-lipophilic balance value near 7. The cloud point of a 1 wt% aqueous solution is reported at approximately 32 °C; above this temperature the polymer separates into finely dispersed hydrophobic droplets and operates as a defoamer, while below this temperature it remains largely water-soluble and may behave as a low-foam wetting agent. This dual behaviour distinguishes L62 from fully water-soluble high-HLB polyethers and from permanently insoluble silicone or mineral-oil defoamers. The product is used in fermentation, metalworking fluids, paper machine water circuits, evaporative cooling systems, and industrial cleaning where silicone residue or hydrocarbon sheen cannot be tolerated. Typical screening dosages begin at 0.05 wt% and are adjusted upward to 0.30 wt% depending on foam stability, solids loading, and process temperature.
The defoaming mechanism of L62 is temperature- and electrolyte-dependent. In deionised water, the ethylene oxide segments remain hydrated below the cloud point of approximately 32 °C, maintaining molecular solubility. As the process fluid approaches or exceeds the cloud point, hydration of the ethylene oxide block weakens, and the polymer separates as finely dispersed hydrophobic droplets. The propylene oxide block adsorbs at the air–water interface, lowers surface elasticity, and accelerates foam film drainage and rupture. The ethylene oxide block retains partial interfacial anchoring, preventing formation of a separate oily surface layer. In real process waters, dissolved electrolytes reduce the cloud point. The magnitude of depression depends on ionic strength and anion type; sodium chloride at 2 wt% may lower the transition temperature by approximately 5–10 °C, although published data for L62 at these specific salt loadings is limited. The result is that a process stream operating at 25–30 °C may still trigger the dispersed-droplet defoaming state if conductivity is high. Conversely, nonionic co-surfactants and certain hydrotropes can raise the cloud point and delay defoaming until higher temperatures are reached. The transition is reversible on cooling, but preferential adsorption onto solids and biomass can remove active polymer from the bulk before the temperature cycle is complete.
Foam film rupture by L62 is not solely a function of low equilibrium surface tension. Effective defoaming requires the polyether to exist as discrete hydrophobic droplets with a size distribution approximately between 1 µm and 20 µm. Droplets larger than 50 µm cream too quickly or act as oil slugs; droplets smaller than 0.5 µm have slower film bridging and may remain trapped in foam lamellae. In high-shear pump systems, droplet size distribution after injection is controlled by shear rate at the feed point and by dilution ratio. Passing a 5 wt% dilution through a centrifugal pump operating above 10,000 s⁻¹ can generate submicron droplets and delay knockdown. Low-shear metering directly into the turbulent foam layer preserves a wider droplet size range and improves response time. Because the material does not form a continuous hydrophobic monolayer after collapse below the cloud point, residual polymer can often be diluted and flushed with water rather than solvent.
Routine incoming specification testing for L62 focuses on viscosity, cloud point, hydroxyl value, and pH because these parameters track batch-to-batch EO/PO ratio and moisture content. Table 1 lists representative acceptance windows from supplier technical bulletins and the corresponding standardised methods used in quality control laboratories.
| Property | Typical value or range | Test method |
|---|---|---|
| Appearance at 25 °C | Clear to slightly hazy liquid | Visual transmission |
| Average molar mass | 2,450–2,500 g/mol | Gel permeation chromatography with polyether calibration |
| Viscosity at 25 °C | 350–450 mPa·s | ISO 2555 |
| Density at 25 °C | 1.00–1.02 g/cm³ | ISO 2811 |
| Cloud point, 1 wt% aqueous | 30–34 °C | DIN EN 1890 |
| pH, 5 wt% aqueous | 5.5–7.5 | ISO 4316 |
| Pour point | -4 °C | ISO 3016 |
| Hydroxyl value | 40–50 mg KOH/g | ISO 14900 |
Viscosity deviation above 450 mPa·s generally indicates high-molecular-weight fraction or water pickup; values below 350 mPa·s suggest contamination with lower-viscosity polyalkylene glycol or retained cleaning solvent. Cloud point below 30 °C in a 1 wt% aqueous solution implies a higher propylene oxide fraction, while cloud point above 34 °C implies a higher ethylene oxide fraction. These differences shift the temperature at which the product converts from soluble surfactant to insoluble droplet and therefore alter the feed point and dilution strategy. Hydroxyl value confirms terminal hydroxyl functionality and is relevant when the product is used in polyurethane or coating systems where reaction with isocyanate groups must be predicted.
In continuous processes, L62 is rarely dosed neat because the 400 mPa·s viscosity makes low-flow metering inaccurate through diaphragm pumps at stroke lengths below 10%. Dilution with demineralised water to 5–10 wt% active concentration reduces viscosity to approximately 10–30 mPa·s, enabling positive-displacement metering in the range of 0.5–5.0 L/h depending on plant capacity. The dilution water should be maintained below 25 °C during mixing and transfer to prevent premature cloud-point phase separation in dosing lines. Low-shear stainless steel static mixers or centrifugal transfer pumps are preferred; high-shear rotor-stator devices can form fine emulsion droplets with slower creaming and interfacial adsorption. In fermentation systems, foam sensors based on capacitance or conductivity are used to activate intermittent injection. A delay of 2–5 min between foam detection and visible collapse is common in protein-rich broth, and premature repeated dosing should be avoided because excess polyether can increase dissolved oxygen demand or act as a carbon source for microbial growth.
Aerobic fermentation processes with high headspace turbulence and complex media generate persistent foam stabilised by cell debris, extracellular polysaccharides, and partially denatured protein. Silicone antifoams based on polydimethylsiloxane or silicone emulsions provide fast knock-down at very low concentrations but can foul microfiltration membranes, reduce oxygen transfer, and leave hydrophobic residues on downstream chromatography resins or heat-exchange surfaces. L62 is selected when these residues are unacceptable. In stirred-tank reactors of 50–100 m³ working volume equipped with multi-stage Rushton impellers and spargers delivering 0.5–1.5 vvm air, injection into the foam layer through a spray nozzle is preferred over bulk-liquid addition. Bulk addition consumes polyether by adsorption onto biomass and air bubbles before the foam interface is reached, increasing the required dose. Production records from aerobic bacterial and fungal systems indicate that split dosing at intervals of 30–60 min maintains foam height more consistently than single-shot addition. The effective dose is generally between 0.01 g/L and 0.10 g/L of initial working volume, but broth-specific titration is required because viscosity above approximately 1,000 mPa·s reduces film drainage and may demand higher dosing. Published data for this specific configuration is limited.
In water-miscible metalworking fluids, L62 acts as both defoamer and low-foam wetting agent. The evaluation range is 0.02–0.20 wt% relative to the diluted sump charge, added to the concentrate before dilution or metered into the recirculation line downstream of the pump. Central systems with tramp oil contamination above 2 wt% may require higher dosing because the oil phase competes for interfacial area and can solubilise part of the propylene oxide block, reducing the concentration available at the air–water boundary. The non-silicone chemistry eliminates the risk of paint adhesion failure and electrocoat craters after part cleaning. In paper machine white-water loops, dilution to 1–5 wt% with demineralised water before addition to the save-all or wire pit is standard practice. Neat addition can create localised high-concentration zones that destabilise rosin size or cationic retention aid, producing scale or deposit issues. At closed headbox temperatures above 35 °C, the cloud-point mechanism contributes to foam knock-down, but fines and filler adsorption remove part of the active polymer. Compensation for filler adsorption is required when headbox ash content exceeds 15 wt%; otherwise foam suppression declines with each short circulation loop. The product can also increase preservative demand in metalworking fluids because the polyether backbone is metabolised by bacteria more readily than silicone or mineral oil.
The selection between L62 and other defoamer types is governed by knock-down speed, persistence, residue risk, and regulatory constraints. Silicone-based products lower surface tension more aggressively and break foam at concentrations below 0.01 wt%, but they can foul filtration membranes, reduce oxygen transfer, and create surface defects in downstream coating. Mineral-oil defoamers are inexpensive for heavy industry but introduce hydrocarbon sheen, increase chemical oxygen demand, and may swell nitrile or natural-rubber seals. High-HLB EO/PO copolymers with HLB values above 12 remain too water-soluble at typical ambient process temperatures and may act as foam stabilisers unless the operating temperature exceeds their cloud point. L62 occupies an intermediate position with HLB near 7 and a cloud point near 32 °C. Within the same polyether family, the lower-HLB L61 grade is more hydrophobic and more effective in oil-contaminated cold streams but difficult to disperse in water; the higher-HLB L64 grade disperses more readily in cold water but requires a higher process temperature to reach its cloud point. Comparative surface tension measurements under ASTM D1331 at 0.1 wt% typically show L62 lowering water surface tension to approximately 42 mN/m, whereas silicone defoamers may reduce surface tension below 25 mN/m; this lower surface tension does not always correlate with better defoaming because film rupture depends on interfacial elasticity rather than equilibrium surface tension alone. Table 2 summarises practical differences under standardised bench conditions.
| Property | L62 EO/PO block polyether | Silicone emulsion | Mineral oil | High-HLB polyether |
|---|---|---|---|---|
| Effective dose in aqueous foaming media | 0.05–0.30 wt% | 0.001–0.01 wt% | 0.1–0.5 wt% | 0.1–0.5 wt% |
| Knock-down speed | Moderate; improves above 32 °C | Fast | Slow to moderate | Slow unless above cloud point |
| Persistence | Low to moderate; consumed by adsorption | High; remains at interface | High; oil droplets persist | Moderate |
| Residue or compatibility risk | No silicone; no oil sheen; may stabilise foam below cloud point | Filtration fouling; coating craters; oxygen transfer reduction | Hydrocarbon sheen; COD increase; elastomer swelling | Low residue; possible foam stabilisation in cold water |
| Temperature boundary | Effective above cloud point 30–34 °C, or with salt depression | Broad | Broad | Requires process above its specific cloud point |
The operational boundary for L62 is process temperature. In cold-water applications below 25 °C, the product may remain molecularly dispersed and can lower dynamic surface tension without breaking established foam, particularly where the foam stabiliser is an anionic surfactant. Under these conditions, a lower-HLB polyether or a small amount of silicone emulsion may be needed. In alkaline cleaning formulations above 60 °C, the EO/PO backbone is chemically stable in the absence of strong oxidisers. Autoclaving at 121 °C can cause colour shifts and minor molecular weight redistribution; therefore repetitive sterilisation should be evaluated for effect on defoaming activity. Avoid combination with amine-based additives in polyurethane or epoxy-cured systems because terminal hydroxyl groups may react with isocyanate crosslinkers and reduce final crosslink density. Published data for this specific configuration is limited.
Regulatory and storage boundaries complete the specification review. L62 is a nonionic polyether with low vapour pressure and is typically classified as non-hazardous under standard workplace criteria. REACH-registered suppliers list the substance under CAS 9003-11-6. Storage in closed stainless steel or polyethylene containers between 5 °C and 40 °C is recommended; prolonged exposure to humid air increases water content and shifts cloud point and viscosity. Pre-drying is required in moisture-sensitive polyurethane or coating operations when ambient relative humidity exceeds 60% or when water content above 0.2 wt% cannot be tolerated. Strong oxidising agents and concentrated hydrogen peroxide at elevated temperature degrade the polyether by radical-mediated ether cleavage. In aerobic biological treatment plants, the ultimate biodegradability of L62 is matrix-dependent; published data for this specific configuration is limited. Use in food-contact or potable-water applications should be confirmed against specific regulatory listings because the generic CAS number alone does not establish food-grade status.
