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| HS Code | 298230 |
| Appearance | Light yellow viscous liquid |
| Active Ingredient Content | 99% |
| Ph 1 Aqueous Solution | 5.0-7.0 |
| Viscosity 25 C | 500-1500 mPa·s |
| Cloud Point 1 Aqueous Solution | 25-35°C |
| Water Solubility | Dispersible in water |
| Ionic Type | Nonionic |
| Density 20 C | 0.95-1.05 g/cm³ |
| Flash Point | >100°C |
| Foam Inhibition Rate | ≥90% (initial) |
| Foam Breaking Speed | ≤10 seconds (typical) |
| Storage Stability | At least 12 months under recommended conditions |
As an accredited Polyether Defoamer LH-301–Polyether Type Defoamer factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Polyether Defoamer LH-301 is packaged in 25 kg or 200 kg plastic drums, tightly sealed to prevent contamination and moisture. |
| Container Loading (20′ FCL) | Polyether Defoamer LH-301 is loaded as a 20′ FCL, typically in drums or IBC totes, safely secured for transport. |
| Shipping | Ship as non-hazardous industrial chemical in sealed HDPE drums or IBC totes. Protect from extreme heat, freezing, and direct sunlight. Use dry, ventilated containers. Avoid prolonged skin contact; keep away from oxidizing agents. Handle with standard PPE. Store upright, secure against shifting during transit. |
| Storage | Store in a cool, dry, well-ventilated area, away from direct sunlight, heat, and ignition sources. Keep the container tightly sealed to prevent moisture ingress or contamination. Avoid storage near strong oxidizing agents. Maintain temperatures between 5°C and 35°C; do not freeze. Under these conditions, shelf life typically remains stable for up to one year. |
| Shelf Life | Shelf life: 12 months from production date when stored in sealed, original containers at cool, dry conditions. |
Application scope for LH-301 is restricted to aqueous and water-borne process streams where silicone-free defoamer chemistry is required by post-process adhesion testing, potable-water contact, food-contact paper regulations, or filtration-membrane compatibility. The six scenarios below address only sectors in which polyether defoamer LH-301 is metered into recirculating loops, high-shear dispersers, jet dyeing machines, paper machine wet-end circuits, metalworking fluid sumps, or aerated bioreactors. Solventborne coatings, anhydrous lubricant bases, and silicone-compatible systems are outside the application boundary. Where published data for LH-301 in a specific equipment configuration is limited, the limitation is stated rather than extrapolated.
| Application boundary | Normative reference | Clause / test method | Relevant condition |
|---|---|---|---|
| Waterborne architectural coatings | Directive 2004/42/EC; ASTM D3601-22 | Annex II subcategory A(c); Method A | Batch temperature 40–50 °C |
| Textile jet dyeing | OEKO-TEX Standard 100; ZDHC MRSL V3.1 | Annex 4 limit values; MRSL formulation screening | Liquor ratio 1:5–1:8 |
| Industrial water treatment | NSF/ANSI/CAN 60; EU Directive 2010/75/EU | Health effects criteria; BAT conclusions for wastewater treatment | Continuous metering 1–10 mg/L |
| Pulp and paper wet-end | FDA 21 CFR 176.210; EU Regulation (EC) No 1935/2004 | 21 CFR 176.210; Article 3 overall migration | Machine speed above 1200 m/min |
| Metalworking fluid sump | REACH Annex XVII; ISO 6743/7 | Restriction screening; MWF classification | Hard water above 400 ppm CaCO₃ |
| Fermentation and bioprocessing | FDA 21 CFR 173.340; OECD 301B | Defoaming agent screening; ready biodegradability | Sterilisation at 121 °C |
In aqueous architectural coating lines equipped with a 1.5–2.0 m high-speed disperser, foam generation concentrates at the Cowles blade vortex where tip speed reaches 18–25 m/s and batch temperature is held at 40–50 °C. LH-301 is added at 0.1–0.3 wt% of total formulation weight, split 50/50 between the pigment grind and the letdown vessel; addition above 0.5 wt% has been associated with cratering and intercoat adhesion loss in acrylic latex semigloss systems. The grind-stage portion is metered into the disperser vortex after 5–10 minutes of pigment wetting, while the letdown portion is post-added through a diaphragm pump after the final resin letdown at peripheral speed below 5 m/s. Foam-control efficiency is evaluated by ASTM D3601-22, and pigment fineness is monitored with a Hegman gauge under ISO 1524:2013. Regulatory compliance follows Directive 2004/42/EC Annex II for waterborne decorative paints. Terminal products include interior matt wall paint, exterior satin facade paint, waterborne wood primers, and 70–80 wt% pigment concentrates supplied to tinting systems.
Because foam persistence in polyester jet dyeing at 130 °C is driven by liquor ratio, nozzle shear, and carrier surface activity, LH-301 is introduced into the preparation tank before dye addition at 0.5–2.0 g/L, or at 0.1–0.5% on weight of fabric for continuous pad-thermosol lines. In soft-flow machines operating at liquor ratios of 1:5 to 1:8, the defoamer must survive nozzle pressures of 1.0–3.0 bar and fabric speeds of 200–600 m/min without depositing hydrophobic residues on polyester or polyamide. Foam layers in the expansion chamber reduce fabric drive efficiency and create crease marks that lower dyeing uniformity; silicone-free LH-301 is used where post-dyeing coating adhesion is measured under ISO 2411:2023, while dyed goods are assessed for colour fastness under ISO 105-C06:2010. Compliance is set by OEKO-TEX Standard 100 Annex 4 limit values and ZDHC MRSL V3.1 for restricted substance screening in textile formulations. Terminal outputs include dyed polyester/cotton single jersey, automotive headliner warp knit, continuous-dyed woven sheeting, and technical spacer fabric.
Where polyether defoamer is metered into activated sludge aeration basins, the primary operational boundary is not foam height but oxygen transfer efficiency across fine-bubble diffusers. In municipal MBR trains, LH-301 is continuously injected at 1–10 mg/L of mixed liquor through progressive cavity pumps, while conventional activated sludge plants treating food-processing effluent may require 5–50 mg/L during shock-loading events. Foam collapse time is screened by ASTM D3601-22; the same method is applied before full-scale trials to adjust dose. In dissolved-air flotation thickeners, addition is made to the pressure release zone rather than the saturation tank to avoid restricting bubble nucleation. Compliance for potable-water contact requires product-specific evaluation under NSF/ANSI/CAN 60; industrial cooling circuits discharging to surface water are operated under EU Directive 2010/75/EU BAT conclusions for wastewater treatment. Terminal process streams include municipal secondary effluent for reuse, food-plant dissolved-air flotation sludge, cooling tower blowdown, reverse-osmosis concentrate, and reclaimed irrigation water.
Paper machine whitewater loops accumulate air-entrained fines and colloidal rosin size, producing a foam mat that destabilises headbox slice jet uniformity at machine speeds above 1200 m/min. Wet-end dosing of LH-301 is set at 0.05–0.30 kg per tonne of dry fiber, introduced into the wire pit or deaerator return line after the disc refiner and before the fan pump; coating-colour addition is 0.1–0.5 wt% on dry pigment in blade-coating formulations. Direct headbox injection is avoided because shear at the slice and forming fabric can split the defoamer droplet phase, producing deposition on polyurethane foil blades and felt fill-in. In closed whitewater systems, the addition point is interlocked with a deaeration cyclone pressure signal, and feed is reduced when air content in the headbox approach system remains below 0.5 vol%. Compliance is governed by FDA 21 CFR 176.210 for defoaming agents used in the manufacture of paper and paperboard, by BfR Recommendation XXXVI/1 for food-contact board, and by EU Regulation (EC) No 1935/2004 Article 3 for overall migration limits. Terminal grades include tissue, folding boxboard, coated art paper, and release liner base stock.
A central coolant sump of 40–60 m³ capacity servicing high-pressure through-tool coolant delivery at 200–1000 L/min represents the most foam-labile point in metalworking fluid service. LH-301 is incorporated into semi-synthetic MWF concentrate at 0.05–0.2 wt% during the coupling step after emulsifier inversion; service-sump top-up is 0.01–0.05 wt% of the circulating volume when foam height in the return flume exceeds 50 mm. Hard water above 400 ppm CaCO₃ tends to reduce polyether defoamer solubility, and pre-dilution in demineralised water at a 1:5 ratio is required before sump injection to prevent deposition on way-lube separators. In high-pressure pump loops, entrained air increases cavitation-induced spall on tooling edges; defoamer addition is therefore tied to return-line foam detection rather than scheduled make-up. The relevant regulatory framework is EU CLP Regulation (EC) No 1272/2008 for labelling, REACH Annex XVII for restricted substances, and ISO 6743/7 for classification of metalworking fluid products. Terminal finished types include water-miscible grinding coolant, multi-spindle machining fluid, drawing lubricant emulsions, and aqueous rust-preventive fluids.
Across aerobic stirred-tank fermentations, polyether defoamer is expected to survive 121 °C autoclave sterilisation and 1.0–1.5 vvm air sparging, conditions that can destabilise ester-based antifoams but are compatible with ether-linked polyether backbones. LH-301 is fed continuously at 0.01–0.1% v/v of working volume from a sterile addition tank through a peristaltic pump, beginning at the late exponential growth phase when foam rises into the headspace above the impeller shaft. In citric acid, amino acid, and industrial enzyme fermentations, the additive partitions into biomass solids and ion-exchange waste streams; discharge compliance is therefore assessed by OECD 301B ready biodegradability and by site-specific wastewater permits. Where the fermentation broth enters human food chain processing, defoamer selection is evaluated under FDA 21 CFR 173.340 for defoaming agents used in food processing. Published data for LH-301 autoclave survival in high-protein fermentation broths is limited; plant qualification typically compares foam rise at 24 h and 48 h using shake-flask screening before scale-up. Terminal product types include citric acid monohydrate, L-lysine HCl, protease and amylase liquid concentrates, and fuel ethanol.
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Polyether Defoamer LH-301 is a polyether-type defoamer based on ethylene oxide/propylene oxide block copolymer chemistry. The product is described as a non-silicone foam control agent for aqueous formulations in which mineral oil or silicone addition is constrained by surface defect risk, intercoat adhesion requirements, or regulatory restrictions. The LH-301 designation identifies a controlled EO/PO structure with specified cloud point behavior, active content, and terminal functionality. The exact batch release values for appearance, dynamic viscosity, density, pH, cloud point, hydroxyl value, acid value, moisture content, and active matter are stated on the manufacturer’s certificate of analysis and technical data sheet. Method designations used for lot release include ISO 2555 for Brookfield viscosity, ASTM D1217 for liquid density, ISO 976 for pH of aqueous dispersion, GB/T 12008.3 for hydroxyl value, and GB/T 6283 for moisture by Karl Fischer titration.
The defoaming mechanism is governed by temperature-induced insolubility rather than by the spreading of a discrete mineral oil or silicone oil phase. In aqueous media, the block copolymer remains compatibilized below its cloud point. As the system temperature approaches the cloud point, the polymer dehydrates, forms fine hydrophobic droplets, and partitions at foam lamellae. Droplet entry, local spreading, and bridging–dewetting destabilize the foam film; interfacial tension gradient disruption also contributes to lamella drainage. The spreading tendency of a droplet can be described by S = γ_L − (γ_D + γ_DL), where γ_L is surface tension of the foaming liquid, γ_D is surface tension of the defoamer, and γ_DL is interfacial tension between defoamer and liquid. A positive value supports spreading, but film rupture additionally requires bridging and de-wetting. For many commercial polyether defoamers of this type, cloud point is controlled within 20°C to 40°C; the LH-301 batch certificate states the release value for the specific lot.
The inverse solubility transition is not a sharp melting point; it occurs over a narrow temperature interval that depends on polymer chain length and EO/PO distribution. In a formulated paint, cosolvents, surfactants, and resin components can depress or elevate the cloud point by several degrees. Defoaming activity is therefore not predicted from the neat cloud point alone. The defoamer must be evaluated in the complete formulation at the maximum expected process and storage temperature. Below the cloud point, the product may act primarily as a deaerator and may not control macrofoam; above the cloud point, the polymer-rich droplets can agglomerate if the shear is insufficient.
The hydrophobic polyoxypropylene segment lowers interfacial tension and supports defoamer entry into foam films; the hydrophilic polyoxyethylene segment provides water dispersibility and inverse solubility. A higher polyoxypropylene content generally shifts the cloud point lower and increases defoaming activity in warm aqueous systems, whereas a higher polyoxyethylene content raises the cloud point and improves compatibility at low temperature. The calculated HLB for defoamer-grade polyether block copolymers is commonly below 10; values above 12 tend to produce wetting-agent behavior rather than defoaming. LH-301 is therefore not interchangeable with polyether defoamers having different EO/PO ratios or terminal modifications. Substitution should be followed by revalidation of foam control, gloss, and recoatability in the target formulation.
Batch-to-batch differences in the controlled polyether structure may shift the defoaming temperature window when the process operates within 2°C of the cloud point. The certificate of analysis provides the cloud point tolerance, and the manufacturer’s release limits are part of the specification. Published data for the specific LH-301 configuration is limited; application-specific evaluation against an incumbent or control formulation is required before line adoption.
At batch release, LH-301 is controlled for parameters that affect pumpability, dispersibility, and functional activity. The following table lists parameters commonly controlled for polyether defoamers in this product class; the lot-specific certificate of analysis takes precedence over any generic range.
| Parameter | Reference method | Unit | Typical commercial range or control basis |
|---|---|---|---|
| Appearance | Visual inspection | — | Clear to slightly hazy viscous liquid without gel or sediment |
| Dynamic viscosity at 25°C | ISO 2555 | mPa·s | 50 to 1,500; certified value on certificate of analysis |
| Density at 25°C | ASTM D1217 | g/cm³ | 0.95 to 1.05; certified value on certificate of analysis |
| pH, 1% aqueous dispersion | ISO 976 | — | 5.0 to 7.0; certified value on certificate of analysis |
| Cloud point | GB/T 5559 or DIN EN 1890 | °C | 20 to 40; certified value on certificate of analysis |
| Hydroxyl value | GB/T 12008.3 | mg KOH/g | Certified value on certificate of analysis; typical defoamer grades fall between 18 and 56 |
| Acid value | GB/T 12008.5 | mg KOH/g | Not more than 0.5; certified value on certificate of analysis |
| Moisture | GB/T 6283 | % | Not more than 0.5; certified value on certificate of analysis |
Hydroxyl value is a structural indicator of chain length and is controlled because it correlates with cloud point and compatibility. Acid value is monitored because free acidity can indicate hydrolysis or contamination during storage. Moisture content is specified because water ingress into a 100% active polyether can cause phase separation or reduce activity. If the product is supplied as an aqueous dilution, the active content is determined by solids or nonvolatile content method. Specifications alone do not guarantee performance. Foam knockdown, persistence, and film compatibility are application-dependent properties and must be measured in the intended formulation using defined foam-generation and drawdown methods. The product is not a wetting agent; foam control should be optimized with the defoamer addition level and not by replacing substrate wetting or pigment dispersion agents.
In waterborne high-gloss acrylic topcoat production, addition point and shear history determine whether the defoamer acts as a compatible defoamer or as a source of craters and haze. Production-scale evaluations with high-speed dispersers have shown that a single addition of the full defoamer charge directly to the letdown can produce large coalesced droplets with poor defoaming efficiency and visible surface defects. A split addition is therefore used: approximately 70% of the total defoamer charge is introduced during the pigment slurry grind stage, where high shear reduces droplet size; the remaining 30% is added during letdown to control foam generated by binder addition and final viscosity adjustment.
Dispersion equipment should provide a tip speed of 10 m/s to 15 m/s for 10 min to 15 min; a Cowles blade of 0.3 to 0.5 tank diameter is appropriate. Low-shear propellers or drum rolling are not adequate for dispersing the defoamer to the required droplet size distribution. The initial screening addition level for polyether defoamers of this grade is commonly between 0.1 wt% and 0.5 wt% of total batch weight. A ladder series should be prepared to identify the minimum dose that passes the target foam test without reducing gloss or recoatability. In high-gloss clear coatings, addition above 0.8 wt% may produce visible haze or reduce 20° specular gloss; the threshold is formulation-dependent and must be confirmed by drawdowns on sealed Leneta charts according to ASTM D523-14. Recoat adhesion after defoamer addition is assessed by cross-cut testing to DIN EN ISO 2409 and, if required, pull-off testing to ISO 4624.
Foam control can be screened with a high-speed disperser foam test in which a fixed volume of paint is mixed at controlled rpm and density reduction is measured after a fixed time. For metalworking fluids or wastewater applications, cylinder shaking and recirculation testing are used. The replacement of an incumbent defoamer with LH-301 should be based on a controlled performance comparison using the plant’s standard foam test, not solely on nominal addition rate.
Outside coatings, polyether defoamers of this type are evaluated in paper coating colors, fountain solutions, metalworking fluid concentrates, and wastewater treatment. In paper coating, the defoamer is usually added to the coating kitchen along with starch or synthetic binder, and the target addition is established by air content measurement before blade coating. In metalworking fluids, compatibility with emulsifiers and corrosion inhibitors is evaluated by thermocycling between −5°C and 40°C and by emulsion stability measurement; the optimum dose is the lowest addition that controls foam without separating the emulsion or staining the metal surface.
Selection among polyether, mineral oil, and silicone defoamers is determined by compatibility, persistence, and the risk of surface defects. Mineral oil defoamers rely on a hydrophobic carrier and often contain hydrophobic silica; they are low-cost but can contribute to surface oil separation, loss of gloss, and recoatability problems in high-performance waterborne coatings. Silicone defoamers, usually based on polydimethylsiloxane or organomodified siloxanes, provide very low surface tension and high foam-breaking efficiency at low dosage but may cause craters, fisheyes, and intercoat adhesion loss if not dispersed completely. LH-301 occupies an intermediate position: it generally provides higher compatibility and recoatability than mineral oil or silicone in high-gloss waterborne systems, while providing less long-term persistence than a highly active silicone defoamer.
| Attribute | Polyether LH-301 | Mineral oil defoamer | Silicone defoamer |
|---|---|---|---|
| Main chemistry | EO/PO block copolymer | Paraffinic or naphthenic oil with hydrophobic silica | Polydimethylsiloxane or organomodified siloxane |
| Typical use level | 0.1–0.5 wt% | 0.1–0.7 wt% | 0.01–0.3 wt% |
| Defoaming persistence | Moderate; temperature-dependent near cloud point | Moderate; may be extracted or saponified in alkaline media | High; may persist through repeated cycles |
| Surface defect risk | Low to moderate if properly dispersed | Moderate; oil exudation and fisheyes possible | High in recoat-sensitive systems |
| Recoatability | Generally retained; tested to DIN EN ISO 2409 | May be impaired if surface contamination occurs | May require surface preparation before recoating |
| Primary limitation | Temperature window and overdose sensitivity | Compatibility and limited high-temperature stability | Cratering and adhesion risk at low overdose |
The choice of LH-301 over other polyether defoamers should be based on cloud point and EO/PO ratio. Polyether defoamers with higher EO content may be more water-compatible but less defoaming at low temperature; grades with lower cloud point may defoam above 30°C but can cause turbidity or seeding if used below their solubility limit. LH-301 should not be considered a drop-in replacement for all polyether grades; the finished formulation must be tested for viscosity stability, gloss, haze, foam density, and recoat adhesion.
Storage should be in sealed containers at 5°C to 35°C, protected from direct sunlight and moisture ingress. If frozen, the product should be warmed gradually to 20°C to 25°C and homogenized before use; repeated freeze–thaw cycles may change the droplet size distribution and should be avoided. Strong cationic coagulants, high levels of non-compatible wetting agents, or formulations with pH above 9.5 may shift the effective cloud point or induce separation; compatibility should be verified in a sealed jar test at the intended use temperature. Typical shelf life for polyether defoamers of this class is 12 months in unopened containers; after prolonged storage, the product should be homogenized and checked for viscosity and pH before use. The product is not automatically approved for food-contact applications; compliance statements, including FDA 21 CFR 176.210 or 21 CFR 175.300 where relevant, must be verified against the current safety data sheet and regulatory documentation for the specific application and region.
