Section
| HS Code | 874459 |
| Product Name | Polyether Defoamer MPE–MPE Type Polyether Defoamer |
| Appearance | colorless to light yellow transparent liquid |
| Active Content | 99% |
| Ph Value | 6.0-8.0 (1% aqueous solution) |
| Viscosity At 25 C | 300-800 mPa·s |
| Cloud Point | 20-40°C (1% aqueous solution) |
| Water Solubility | dispersible or soluble in water depending on formulation |
| Defoaming Efficiency | rapid foam knockdown in aqueous systems |
| Foam Suppression Duration | long-lasting foam inhibition in circulating water and industrial processes |
| Emulsion Compatibility | excellent compatibility with nonionic and anionic surfactants |
| Thermal Stability | stable up to 120°C |
| Chemical Resistance | resistant to acids, alkalis, and electrolytes |
As an accredited Polyether Defoamer MPE–MPE Type Polyether Defoamer factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Packaged in 200 kg plastic drums or 1,000 kg IBC totes; sealed, labeled, and safe for transport and storage. |
| Container Loading (20′ FCL) | 20′ FCL: Polyether Defoamer loaded in 200kg drums or IBC totes, palletized, securely blocked and braced for safe transit. |
| Shipping | Polyether Defoamer MPE–MPE Type ships in sealed plastic drums or IBC totes, protected from moisture and direct sunlight. Keep containers upright and avoid extreme temperatures during transit. Non-hazardous classification reduces restrictions, but standard industrial handling, proper labeling, and secure palletization ensure safe, leak-free delivery worldwide. |
| Storage | Store Polyether Defoamer MPE in a tightly sealed container in a cool, dry, well-ventilated area. Protect from direct sunlight, extreme heat, and freezing temperatures. Keep away from strong oxidizing agents and ignition sources. Maintain between 5–35°C. Under proper conditions, shelf life is typically 12 months. Stir gently before use if stored long-term. |
| Shelf Life | Shelf life is typically 12 months when stored in sealed containers, away from direct sunlight and extreme temperatures. |
In submerged aerobic fermentation vessels with working volumes between 50 m³ and 500 m³, uncontrolled foam accumulation reduces working volume, forces premature harvest, and increases contamination risk at the headspace pressure boundary. MPE-type polyether defoamer is metered into the broth through sterile diaphragm dosing pumps at 0.01–0.10 wt% of total broth mass, split between initial batch charge and feed-linked additions during the logarithmic growth phase. Compliance is governed by 21 CFR 173.340 where the fermentation output enters food use, by 21 CFR 210/211 for pharmaceutical fermentation, and by EU Regulation 1935/2004 where the fermented product enters indirect food contact. The downstream process includes inline steam sterilization of the defoamer at 121–125 °C for 30 min, cooling to 37–55 °C depending on the producing organism, and aseptic transfer into seed and production vessels equipped with radial-flow Rushton impellers and air sparge rings. Terminal product types include pharmaceutical antibiotics, industrial enzymes, amino acids, organic acids, yeast and probiotic biomass, and recombinant proteins. Foam height is monitored with capacitance probes inserted through the top plate, and defoamer addition is interlocked with agitator power draw and oxygen uptake rate. When stored at 10 °C or below, viscosity increases sufficiently to require heated trace lines; diaphragm pump suction lift should not exceed 3 m to avoid cavitation.
The persistence of macro-bubble foam in waterborne latex formulations after pigment dispersion is linked to latex emulsifier desorption and stabilization of air-water interfaces by low-molecular-weight surfactants. MPE-type polyether defoamer is introduced at two distinct addition points: 0.1–0.3 wt% of the total formulation during the grind phase to suppress air entrainment under a Cowles disperser with tip speed between 15 m/s and 25 m/s, and 0.1–0.2 wt% during letdown under low-shear paddle agitation at 200–500 rpm. Compliance for architectural coating applications references ASTM D3519-88(2013) for foam generation in aqueous media, ASTM D6736-08(2015) for scrub resistance retention, and DIN EN ISO 4618:2014 for classification and terminology. High-speed dispersion is performed in 500–2,000 L tanks with a depth-to-diameter ratio of 1.2:1, and foam knockdown time is assessed by blade-out sparge test. Production-scale tinting and filling lines use 50–200 L rotary can fillers where air bubbles introduced during filling must collapse before lid closure to prevent weight deviation and rusting. Terminal product types include interior and exterior styrene-acrylic and vinyl acetate-ethylene latex paints, primer systems, elastomeric wall coatings, and waterborne floor enamels. Pre-blending with cationic associative thickeners at pH below 8.5 is avoided because insoluble complex formation reduces defoamer activity.
Where vacuum dewatering demands entrapped air release without disturbing fiber flocculation or sheet formation, MPE defoamer is dosed into thick stock and white-water loops at 0.02–0.10 wt% based on oven-dry fiber mass. Compliance for food-contact paper and paperboard is defined by 21 CFR 176.170, BfR Recommendation XXXVI/2, and EU Framework Regulation 1935/2004; for packaging not intended for food contact, mill discharge limits under EU Industrial Emissions Directive 2010/75/EU require low COD contribution and high retention in the sheet. The downstream production process involves addition to the machine chest before the dilution line, passage through pressure screens and a headbox with slice opening between 6 mm and 25 mm, then drainage on a fourdrinier or twin-wire former at speeds up to 1,800 m/min. White-water solids are maintained at 0.3–0.8% and temperature at 45–55 °C; the defoamer is diluted to 1:10 with white water before dosing. Foam control is critical in the wire pit because entrained air reduces drainage rate and creates pinholes in the sheet. Terminal product types include tissue, corrugating medium, white-top linerboard, coated paper, and food-grade packaging board. Overdosing above 0.15 wt% on oven-dry fiber can produce hydrophobic deposits on forming fabrics.
At 135 °C in a high-pressure overflow jet dyeing machine with a liquor ratio of 1:5 to 1:8, foam generated by residual sizing agents, lubricants, and anionic surfactants collapses the circulation pump pressure and causes rope crease marks on polyester. MPE-type polyether defoamer is pre-dispersed in water at 1:10 and metered into the dye bath at 0.5–2.0 g/L of bath volume, equivalent to 0.05–0.20 wt% on fabric mass. The relevant chemical compliance boundary is ZDHC MRSL Version 3.1, which excludes alkylphenol ethoxylates and certain solvent carriers, and Oeko-Tex Standard 100 for residual defoamer on finished textile substrates. Downstream production includes open-width alkaline scouring at 95–100 °C for 30–45 min, intermediate rinsing, acid neutralization, high-temperature dyeing, reduction clearing, and stenter drying at 120–150 °C. Bath circulation rate is maintained at 2–3 kg fabric per liter per minute, and foam head is monitored in the pressure vessel sight glass. Terminal product types include woven and knitted polyester, polyester-cotton blends, nylon-spandex activewear, and automotive interior textile. Combination with silicone-based antifoams is avoided in the same bath because competitive adsorption at the air-water interface can reduce MPE efficiency.
Oxygen transfer efficiency in diffused-air basins drops when a 100–300 mm froth layer covers the surface, reducing surface renewal and increasing aerosol release. MPE defoamer is injected into the aeration basin mixed liquor or onto the froth surface at 2–10 ppm by volume of influent flow, with intermittent dosing controlled by foam height sensors at 0.3–0.5 m above the water line. Environmental compliance relies on OECD 301F ready biodegradability with >60% ThCO2 evolution within 28 days, ISO 11733:2004 for activated sludge inhibition testing, and discharge limits under EU Directive 91/271/EEC for chemical oxygen demand. Production-scale equipment includes fine-bubble membrane diffusers operating at air flux rates of 2–5 Nm³/h per diffuser, surface aerators with oxygen transfer rates of 1.5–2.5 kg O₂/kWh, and clarifiers with hydraulic surface loading below 1.2 m/h. Mixed liquor suspended solids are held at 3,000–6,000 mg/L, and foam height sensors trigger dosing only above threshold to avoid excess COD. Terminal outputs are treated municipal and industrial discharge, nitrified effluent for reuse, and dewatered surplus activated sludge. The defoamer is not dosed directly into anaerobic digester gas headspace where pH is above 9.0 because a solubility shift reduces spreading on foam lamellae.
Extended sump life in central coolant systems, defined as operational periods beyond 90 days without full fluid replacement, creates slow accumulation of fine metal fines, tramp oil, and bacterial biomass that raises air entrainment and foam stability. MPE polyether defoamer is blended into semisynthetic and synthetic metalworking fluid concentrates at 0.05–0.20 wt% of the concentrate, yielding in-sump active concentrations between 20 ppm and 100 ppm after 1:20 to 1:30 dilution with plant water. Compliance for metalworking fluid formulations is documented under ISO 6743-7:2016 for fluid classification, ASTM D3519-88(2013) for foam tendency, and TRGS 611 where water-miscible coolants are restricted to biocide packages with specific nitrosamine limits. Downstream central systems include high-pressure pumps supplying 50–120 bar through-the-tool coolant, paper-bed or drum filtration, hydrocyclones removing fines above 20 µm, and tramp oil skimmers with removal rates of 2–8 L/h. Sump pH is maintained at 8.6–9.2 for synthetic fluids, and defoamer is added through trim dosing pumps controlled by central conductivity. Terminal product types include machined aluminum transmission housings, steel camshafts, cast iron brake discs, and bearing-grade turned components. Pre-mixing with high-concentration quaternary ammonium biocides is avoided because emulsion destabilization can occur before dilution.
Low-foam industrial cleaning concentrates for clean-in-place and bottle-washing lines require defoaming that remains effective under high-shear spray impingement and high-temperature recirculation. MPE-type polyether defoamer is incorporated into concentrated liquid detergents at 0.5–2.0 wt% of the concentrate, with final use concentrations in cleaning solution between 50 ppm and 400 ppm after dilution. Compliance is defined by EU Detergent Regulation (EC) No 648/2004 including Annex VII biodegradability, and OECD 301B ready biodegradability for the final formulation. The production process involves high-pressure CIP spray nozzles operating at 2–5 bar and 60–85 °C, recirculation tank volumes of 5–20 m³, and tunnel bottle washers operating at 80 °C with caustic concentrations from 1–3 wt%. Concentrates are blended in 500–2,000 L vessels with low-shear propeller mixers, and samples are aged at 40 °C for 12 weeks to verify foam control stability. Terminal product types include CIP detergents for dairy, brewery, beverage, and food processing plants, as well as bottle-washing compounds for glass and returnable PET containers. Formulations containing active chlorine above 5% are avoided because polyether backbone oxidation reduces foam suppression over shelf life.
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Polyether Defoamer MPE–MPE Type Polyether Defoamer is classified as a non-silicone, water-insoluble polyoxyalkylene block copolymer produced by sequential alkali-catalysed addition of propylene oxide to a polyhydric initiator, followed by ethylene oxide capping. The MPE designation refers to a cloud-point-regulated molecular architecture in which the hydrophobic polyoxypropylene segment lowers surface tension and destabilises foam lamellae, while the terminal polyethylene oxide block provides controlled cold-water dispersibility. Typical industrial grades are supplied as clear liquids with Pt-Co colour values below 80 and no visible sediment. The material is applied in alkaline paper-machine stock preparation, textile jet dyeing, cooling-water circuits, and fermentation broths, where silicone-based products may create deposit or barrier-coating defects. Batch release certificates for MPE–MPE grade materials generally record hydroxyl value, acid value, water content, pH, viscosity, and cloud point because these parameters jointly define molecular size, end-group lability, electrolyte tolerance, and storage stability.
Unlike conventional glycol-based wetting agents, the MPE–MPE product functions by entering the foam film as a dispersed phase rather than by reducing bulk surface tension permanently. The resulting dewetting and film-rupture behaviour is strongly temperature-dependent because the polyether chain exceeds its cloud point and precipitates as fine hydrophobic droplets. This precipitation threshold is the principal operational boundary for process selection.
The following representative limits are compiled from manufacturer technical documentation for MPE-type polyether defoamers used in paper and water treatment. The methods are cited to permit transfer of the release data between supplier and process laboratories. Viscosity is measured on neat product at 25 °C using a rotational viscometer according to ISO 2555:2018. Cloud point is determined on a 1 wt% aqueous dilution under ASTM D2024-09. Hydroxyl value and acid value are determined by wet titration against standardised reagents per ASTM D4274-21 and ASTM D7253-16, respectively.
| Parameter | Control limit | Test method |
|---|---|---|
| Appearance, Pt-Co colour | Clear liquid, ≤ 80 Pt-Co | ASTM D1209-05(2019) |
| Hydroxyl value | 45–56 mg KOH/g | ASTM D4274-21 |
| Acid value | ≤ 0.5 mg KOH/g | ASTM D7253-16 |
| Water content | ≤ 0.5 wt% | ASTM E203-16 |
| pH, 1% aqueous dispersion | 5.0–7.0 | ISO 4316:1977 |
| Cloud point, 1 wt% aqueous | 15–22 °C | ASTM D2024-09 |
| Viscosity at 25 °C | 400–1000 mPa·s | ISO 2555:2018 |
| Density at 20 °C | 1.00–1.05 g/cm³ | ISO 2811-1:2016 |
Variation within these ranges arises from intentional molecular weight targeting and from the ethylene oxide/propylene oxide molar ratio. A higher ethylene oxide content increases cold-water dispersion and may depress the cloud point, whereas a higher propylene oxide content increases foam-breaking activity in hot stock.
Mechanistically, the MPE–MPE polyether enters the foam lamella as small droplets. The thermodynamic condition for spontaneous spreading across the lamella surface is expressed as S = γ_f − γ_d − γ_f/d, where γ_f is the foam liquid surface tension, γ_d the defoamer surface tension, and γ_f/d the interfacial tension between foam liquid and defoamer droplet. For a silicone-free polyether against an anionic surfactant foam, a positive spreading coefficient is achieved when the defoamer surface tension falls below the foam liquid surface tension by at least the interfacial penalty. In laboratory evaluations with a pendant-drop tensiometer operated under ISO 304, the MPE–MPE material usually displays a surface tension of 30–35 mN/m, while the interfacial tension against a 0.1 wt% sodium dodecylbenzenesulfonate solution remains in the 2–6 mN/m range. Droplet bridging can dominate near cloud point because the precipitated polyether phase is more hydrophobic and forms lenses at the air-water interface. The resulting film thinning is measured on a thin-film balance; published data for this specific configuration is limited, but the qualitative transition from spread-film to lens-driven rupture is well documented for ethylene oxide/propylene oxide block copolymers.
In alkaline fine-paper wet-end service, MPE–MPE is metered neat or as a 1:10 dilution in demineralised water through a low-shear positive displacement pump. The preferred injection point is the fan-pump suction or the machine chest discharge, where distributive mixing occurs before pressure screens and the headbox. Technical bulletins list addition rates of 0.01–0.1 wt% on dry fibre. The lower bound is used for intermittent foam excursions on bleached kraft furnishes; the upper bound is reserved for peroxide-bleached mechanical pulp lines with high fatty acid and resin acid carryover. Foam control is verified on a dynamic drainage analyzer and on a foam cycler at 45–50 °C. Published data for this specific configuration is limited because mill-specific anionic trash level and filler loading alter the mass transfer of the defoamer between fibre surfaces and the aqueous phase.
In paper coating colour preparation, MPE–MPE is incorporated during the final stage of starch letdown rather than during pigment grind. The addition level is 0.05–0.3 wt% based on wet coating mass. The equipment used for validation includes a low-shear Brookfield viscometer and a Hegman grind gauge; entrained air is measured by density cup under ISO 2811-1:2016. High-shear dissolver operation above 10 m/s tip speed can reduce the defoamer droplet size below the critical entry threshold, and microfoam persists. This effect is observed in blade coating trials at 800 m/min machine speed where pinholing appears in the dried film; published data for this specific configuration is limited.
Cooling-water and fermentation applications use lower dosages, commonly 0.001–0.01 wt% of recirculating volume. The product is introduced at the suction side of the circulating pump or into the quench tower basin through a chemical metering skid. Because the polyether is water-insoluble but dispersible, continuous agitation is required after dilution; stagnant storage of a pre-diluted 1% mixture can produce a cream layer that changes the effective feed concentration. The operational boundary is therefore narrow in low-flow post-dilution lines.
Cloud point depression is the primary incompatibility in high-electrolyte process water. In deionised water, the MPE–MPE grade is specified at 15–22 °C; in a 5 wt% sodium chloride brine the phase separation threshold can shift downward by 5–10 °C because chloride ions disrupt the hydration shell of the polyethylene oxide block. This means that a grade with a cloud point of 20 °C may self-separate prematurely in brackish cooling water already warm at 25 °C, losing the dispersed droplet size needed for film penetration. The effect is non-linear and should be revalidated by cloud-point titration under ASTM D2024-09 at the intended electrolyte concentration before changing dose strategy.
Anionic trash in paper stock, including oxidised lignin sulfonates and dispersed rosin size, competes with the polyether for the air-water interface. High levels of anionic polyacrylamide or naphthalene sulfonate dispersants can form coacervate complexes with the ethylene oxide segments and reduce defoaming efficiency. In such systems, the feed point should be moved upstream of the pressure screens, not downstream into the headbox, to increase contact time and avoid localised surface deposits on forming fabric. The product should not be premixed with cationic polyamine retention aids or strong oxidants such as sodium hypochlorite at pH above 10; hypochlorite can cleave polyoxypropylene chains and generate low-molecular-weight fragments that raise foam stability instead of suppressing it.
At machine-stock temperatures above 50 °C, the product may lose deaeration ability in low-shear zones. In thermomechanical pulp refining, addition should be made after latency chest cooling to below 45 °C. In coating kitchens, MPE–MPE is added at 0.05–0.3 wt% on wet coating weight only after starch cooking and cooling, because high temperatures during jet cooking degrade the cloud-point response irreversibly.
The MPE–MPE product differs from silicone defoamers in molecular mechanism and residue behaviour. Silicone antifoams based on polydimethylsiloxane and hydrophobic silica possess surface tensions in the range 19–21 mN/m, which is lower than aqueous surfactant solutions; they produce fast knockdown and persistent films but can carry over into size press formulations and create fish-eye defects. MPE–MPE polyethers exhibit surface tensions closer to 30–35 mN/m, which is less aggressive but more compatible with downstream sizing and coating agents. Mineral oil defoamers typically require higher doses and leave hydrocarbon residues that reduce sheet brightness and interfere with polyvinyl acetate coating adhesion.
| Chemistry | Active liquid cloud point | Surface tension of active liquid | Typical use concentration | Primary deposit risk |
|---|---|---|---|---|
| MPE–MPE polyether | 15–22 °C | 30–35 mN/m per ISO 304 | 0.01–0.1 wt% dry fibre | Phase separation above cloud point; coacervate with anionic dispersants |
| Silicone PDMS/silica | Not applicable | 19–21 mN/m per ISO 304 | 0.001–0.01 wt% by volume | Hydrophobic deposits on fabrics, wires, and coating films |
| Mineral oil/surfactant | Not applicable | 30–32 mN/m per ISO 304 | 0.1–0.5 wt% by volume | Hydrocarbon carryover; brightness loss; tacky dryer deposits |
The comparison is structural, not purely efficiency-based, because foam persistence depends on the surfactant inventory of each process stream. For food-contact paper stock, individual MPE–MPE grades may be suitable for 21 CFR 176.170 and 21 CFR 176.180 clearances only when the polymerised monomers and initiators are listed in the applicable regulation; this status must be confirmed by the supplier for the specific production lot. Silicone defoamers frequently require separate regulatory review under 21 CFR 173.340 when used in direct-contact food-processing applications, which is not automatically transferable to paper mill service.
In textile jet dyeing, MPE–MPE is used where silicone softeners or fluorocarbon finishes are applied after dyeing. Silicone defoamer carryover can produce dye spots and uneven water repellency; polyether breakdown at high dyeing temperature is avoidable by selecting a higher-propylene oxide grade or by injecting into the overflow chamber rather than the pressurised pump intake. For polyester dyeing at 130 °C, a higher cloud-point MPE variant is typically used because the standard MPE–MPE grade separates at the dyeing temperature and loses defoaming activity in the first 10–15 min of the high-temperature hold. The standard grade is therefore limited to dyeing cycles below 95 °C or to scouring and rinsing stages.
In fermentation, the product is added before inoculation at 0.005–0.02 wt% of broth volume, and foam control is monitored by exhaust gas mass flow and dissolved oxygen signal stability. Because polyethers can be metabolised more readily than silicone oils, the defoamer half-life in aerated fermentors may be shorter than that of silicone-based products; this difference is managed by continuous feed rather than single charge. Process air flow in a pilot bubble column at 2 vvm can strip low-molecular-weight fractions, shifting the remaining polyether to a higher cloud point and reducing knockdown speed over batches.
Storage stability is controlled by residual water and acid value. A rise in acid value above 0.5 mg KOH/g indicates oxidative degradation or hydrolysis of terminal groups; this can lower molecular weight and alter cloud point. The product should be stored in closed stainless steel or high-density polyethylene containers at 5–40 °C. Exposure to direct sunlight or contact with copper alloys should be avoided because trace copper ions accelerate peroxide formation in polyether chains. The material is not classified as flammable under standard flash-point testing, but it can support combustion at elevated temperatures; therefore local extinguishing media require alcohol-resistant foam.
