Section
| HS Code | 554636 |
| Product Name | Polyether Defoamer G-GP Type |
| Appearance | Colorless to light yellow transparent liquid |
| Active Content | 100% |
| Ph Value 1 Percent Solution | 5.5-7.0 |
| Viscosity 25c | 200-800 mPa·s |
| Cloud Point 1 Percent Water Solution | 25-40°C |
| Water Solubility | Water-dispersible to water-soluble |
| Defoaming Efficiency | Rapid foam break |
| Foam Suppression | Long-lasting foam inhibition |
| Application Temperature | 20-80°C |
| Recommended Dosage | 0.1-1.0% of total formulation |
| Storage Shelf Life | 12 months when stored sealed in cool, dry place |
As an accredited Polyether Defoamer G–GP Type Polyether Defoamer factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Polyether Defoamer G–GP Type is packaged in sealed 25 kg plastic drums or 200 kg iron drums, with clear hazard labeling. |
| Container Loading (20′ FCL) | 20′ FCL: drums/pails on pallets, properly secured, labeled, ventilated, weight-balanced for safe Polyether Defoamer transport. |
| Shipping | Polyether Defoamer G–GP Type is shipped in sealed drums or IBC totes to prevent contamination and moisture ingress. Transport is via standard freight, avoiding extreme temperatures and direct sunlight. Ensure proper labeling, secure loading, and adequate ventilation. No special hazard classification applies, but spill containment and PPE are recommended during handling. |
| Storage | Store in a cool, dry, well-ventilated area away from direct sunlight, heat sources, and open flames. Keep containers tightly sealed to prevent contamination, moisture ingress, or evaporation. Avoid contact with strong oxidizing agents. Recommended storage temperature range: 5–35°C. Under proper conditions, shelf life is typically 12 months from production date. Keep out of reach of unauthorized personnel. |
| Shelf Life | Shelf life is typically 12 months when stored in original sealed containers, kept cool, dry, and away from direct sunlight. |
| Dosage (wt% on total formulation) | Macrofoam Collapse Response | 60° Gloss Retention Relative to Control (ISO 2813:2014) | Crater Formation Probability |
|---|---|---|---|
| 0.05 | Residual microfoam visible after 24 h storage | ≥ 98% | Negligible at standard film thickness |
| 0.10 | Complete macrofoam collapse within 30–60 s | ≥ 98% | Negligible |
| 0.25 | Complete collapse; microfoam suppressed | 96–98% | Low; increases below 7°C application temperature |
| 0.40 | Complete collapse with over-defoaming potential | 92–96% | Moderate on low-energy substrates |
| 0.60 | Over-defoaming; surface texture disruption | < 92% | High; visible pinholes at 75 µm wet film |
| Standard Designation | Scope | Defoamer-Related Requirement |
|---|---|---|
| FDA 21 CFR 176.170 | Components of paper and paperboard in contact with aqueous and fatty foods | Defoamer extractability must remain below regulatory limits in finished sheet |
| ISO 535:2014 | Cobb water absorptiveness | Defoamer must not raise water sizing demand above grade specification |
| ISO 2470-1:2016 | Diffuse blue reflectance factor (ISO brightness) | Brightness reversion must not exceed 0.5 point after defoamer addition |
| EPA 40 CFR Part 430 | Pulp, paper, and paperboard point source effluent guidelines | Defoamer contribution to AOX and COD must stay within permit limits |
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Polyether Defoamer G–GP is a non-silicone, nonionic polyether defoamer supplied as a water-insoluble but water-dispersible liquid. The G–GP designation identifies a glycerol-initiated ethylene oxide/propylene oxide block polyether in which the poly(propylene oxide) segment contributes the hydrophobic defoaming moiety and the ethylene oxide segment controls the cloud point and aqueous dispersion behaviour. The material is not represented by a single CAS registry number; the safety data sheet describes the product as a reaction product of propylene oxide and ethylene oxide with glycerol. Because the technical-grade composition contains an oligomer distribution rather than one molecular species, batch-to-batch control relies on viscosity, density, cloud point, hydroxyl value, and water content rather than on an exact monomer sequence. Incoming goods inspection should compare each batch certificate against the agreed specification; the values quoted in this technical note are typical control ranges, not fixed constants for unqualified lots.
The defoaming mechanism of the G–GP polyether is based on controlled incompatibility at the air–liquid interface. As the continuous phase temperature approaches the cloud point, the product precipitates as fine surface-active droplets that displace foam-stabilizing surfactants and promote coalescence of adjacent bubbles. In deionized water at 0.1–0.3 wt% and 25°C, the equilibrium surface tension of the G–GP dispersion is typically 30–34 mN/m when measured by ASTM D1331-20. A conventional polydimethylsiloxane antifoam emulsion at the same concentration may produce 20–22 mN/m. The higher surface tension is the principal compatibility advantage: it lowers the probability of cratering and intercoat adhesion loss in multi-layer systems. However, the same property means the G–GP grade is not a drop-in replacement for a silicone antifoam when maximum foam knockdown is the only acceptance criterion.
The cloud point of the G–GP type is normally set in the 28–34°C range. This is a key distinction from fatty alcohol defoamers and from polyalkylene glycol grades optimized for hot textile dyeing or boiler feedwater. If the cloud point were below 20°C, the defoamer would remain highly insoluble at ambient temperature and could form visible droplets on wet film surfaces. If it were above 45°C, it would be too soluble in many ambient process fluids and would lose foam-control persistence. A polyether-modified siloxane, by contrast, combines siloxane spreading with some polyether compatibility, but it still contains silicon and can fail recoat tests in automotive paint systems. The G–GP grade contains no silicon; X-ray fluorescence screening for silicon is normally below the detection limit of 50 mg/kg. This absence of silicon is the most significant differentiator in applications where silicone carryover cannot be tolerated.
Mineral oil defoamers reduce initial foam height at low cost, but they introduce free oil into the circulating fluid. In water-miscible metalworking fluid central systems, free mineral oil can separate at the liquid surface, interfere with tramp-oil removal, and restrict filter throughput on fine bag or cartridge units. The G–GP grade contains no mineral oil and does not contribute to total oil as determined by gravimetric acid-split methods. In an alkaline spray cleaner at pH 10.0 and 50°C, the polyether remains dispersed without phase separation for 24 h; a comparable mineral oil defoamer under the same conditions typically forms a visible surface layer within 2–6 h. The polyether is also less likely to saponify or produce sticky deposits on spray-nozzle internals. These differences can be measured by continuous optical turbidity scanning with a Turbiscan LabExpert at 20°C and 50°C, using transmission and backscattering profiles to quantify creaming and flocculation. Published data for this specific configuration is limited; the stated separation times should be treated as production-scale observations rather than universal values.
A second practical difference is persistence under pump recirculation. In a 50,000-L central system recirculated at 2.0–3.0 bar line pressure, a mineral oil defoamer may require re-dosing every 8–24 h because mechanical shear strips the film from the foam interface. The G–GP polyether defoamer, at 0.1 wt% on total volume, can maintain air-release control for 3–7 days under similar conditions. The lower re-dosing frequency is offset by slower initial foam knockdown; users should not expect the shock effect of a silicone concentrate. The product is best suited to continuous systems where persistent control is more important than immediate collapse of a large foam head.
A representative batch of Polyether Defoamer G–GP is controlled to the following typical ranges: Brookfield viscosity 300–600 mPa·s at 25°C using ASTM D2196-20 with spindle 2 at 30 rpm; density 1.00–1.03 g/cm³ at 25°C by ASTM D1475-13; pH of a 1% dispersion in deionized water 5.5–7.5 using ISO 4316:1977; and Karl Fischer water content below 0.3 wt% using ASTM E203-16. The cloud point, measured at 1 wt% in a defined nonionic surfactant solution, is normally 28–34°C by DIN EN 1890:2006. The hydroxyl value is typically 25–45 mg KOH/g by ASTM D4274-21. The pour point is normally -10°C to 5°C by ASTM D97-17b. These ranges are typical release limits; actual batch certificates may show narrower internal control limits. The viscosity of polyether defoamers shifts by approximately −15 to −25 mPa·s per 1°C increase between 20°C and 40°C, so viscosity specimens should be equilibrated in a water bath at 25°C for at least 2 h before testing. Phase separation during storage at 5–35°C is typically reversible; if a light haze develops at low temperature, the product should be warmed to 20–25°C and rolled or gently agitated before use.
The G–GP grade is not classified as dangerous under the CLP Regulation (EC) No 1272/2008; the SDS is prepared in accordance with REACH Annex II. The product should be stored in high-density polyethylene or stainless steel totes. Avoid contact with strong acids below pH 2.0, strong oxidizing agents, and anhydrous aluminum chloride, which can depolymerize the polyether chain. Pre-drying is not required for most waterborne formulations, but storage under high relative humidity is not recommended because slow moisture uptake can raise the Karl Fischer water content above 0.5 wt% and alter the cloud point.
In waterborne architectural coatings, the defoamer is normally added during the let-down stage at 0.1–0.5 wt% on total formulation weight. Addition during pigment grind can improve initial wetting and macro-foam control, but excessive shear may reduce the dispersed droplet size below the effective range and lower defoaming efficiency. On a production-scale high-speed disperser with a Cowles blade running at 8–12 m/s tip speed for 10–15 min, the product is incorporated without generating a separate oil phase. For air-release evaluation, the time for a defined foam volume to collapse is measured according to ASTM D3427-19. In a typical styrene-acrylic semi-gloss formulation, addition of 0.3 wt% G–GP reduces air-release time from 120–180 s to 45–90 s at 25°C. The same formulation retains 95% of its initial 60° gloss when measured by ASTM D523-14, provided the dosage remains below 0.5 wt%. These values are representative batch data; users should validate on their own base formulations because the surfactant package and latex particle size change the compatibility window.
In paper coating colour based on precipitated calcium carbonate and starch, the defoamer is metered into the recirculation line or at the machine tank at 0.05–0.2 wt% based on dry pigment mass. Air entrainment in the coating colour can cause pinholes, skip coating, and blade scratches. The G–GP type is suitable for blade-coater systems because at normal addition rates it does not raise the low-shear viscosity beyond ±5% of the control and has minimal effect on high-shear viscosity measured by a capillary viscometer at 10,000 s⁻¹. Dosing should be continuous rather than slug-dosed; slug addition above 0.3 wt% can cause local incompatibility and surface mottle. For metering, positive-displacement gear pumps with EPDM or PTFE seals are preferred. Progressive cavity pumps should be avoided because the low-viscosity polyether can slip and reduce metering accuracy when viscosity is below 200 mPa·s.
Overdosing above 0.5–0.7 wt% in clear film systems can move the defoamer from the controlled-incompatibility region into visible incompatibility. The first observable change is usually haze development in the wet film, followed by gloss loss after dry-film coalescence. In a clear acrylic wood coating, a dosage of 1.0 wt% can reduce 20° gloss by 5–10 units on a BYK-Gardner micro-TRI-gloss instrument using ASTM D523-14. The effect is temperature-dependent: at 30°C and above, the cloud point is approached more closely and haze risk increases at lower addition levels. For this reason, the upper dosage limit for clear systems is usually set at 0.3 wt%, while pigmented systems may tolerate up to 0.7 wt% because pigment hiding masks low levels of haze. The defoamer should not be post-added at high concentration to a nearly filled tank; a 1:10 pre-dilution in the continuous phase or in a compatible coalescing solvent is recommended before addition to avoid local shock and visible oil streaks.
Compatibility with amine-neutralized dispersants and ammonia-based pH modifiers is generally acceptable at normal use levels. However, acid-catalyzed systems below pH 2.0 can hydrolyze the polyether chain and should be validated by accelerated storage at 50°C for 14 days. The product is not compatible with strong oxidizing agents used in some chemical process streams; contacting with hypochlorite solutions above 5% active chlorine can cause exothermic decomposition and should be avoided. In textile jet-dyeing machines where the liquor is subjected to high shear and rapid temperature ramps, the product is used at 0.1–0.3 g/L; the defoamer is injected into the circulation line rather than into the fabric pack. At temperatures above 80°C, the polyether may become too soluble in the dye liquor and lose defoaming activity; in such cases, a silicone-based grade is often selected, but the silicone contamination risk must be accepted or the process temperature reduced. Published data for this specific configuration is limited.
Polyether Defoamer G–GP is also used in water-based flexographic ink systems where volatile organic content must be minimized. At 0.1–0.4 wt% of the press-ready ink, it controls micro-foam during high-speed pump circulation without increasing dynamic surface tension above 33 mN/m at 10 Hz bubble frequency measured by maximum bubble pressure tensiometry. The absence of silicone and mineral oil reduces plate-blinding and cylinder deposition. Ink formulators should confirm that the product does not react with water-based acrylic varnishes or polyurethane dispersions; a 48-h stability test at 50°C is used to detect gel particle formation before press trials.
