Section
| HS Code | 343829 |
| Product Name | XP-321W Quick Defoaming Polyether-Modified Silicone for Waterborne Systems |
| Appearance | Slightly opalescent to transparent viscous liquid |
| Viscosity Mpa S At 25c | 300 - 800 |
| Ph 1 Percent Water Solution | 6.0 - 8.0 |
| Density G Cm3 At 25c | 0.98 - 1.02 |
| Ionic Type | Nonionic |
| Water Dispersibility | Readily dispersible in water |
| Defoaming Speed | Fast / quick foam breaking |
| Foam Suppression | Long-lasting foam inhibition |
| Compatibility | Compatible with most waterborne resin systems |
| Storage Stability | Stable when stored sealed in a cool, dry place |
As an accredited XP-321W Quick Defoaming Polyether-Modified Silicone for Waterborne Systems factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | XP-321W Quick Defoaming Polyether-Modified Silicone for waterborne systems, supplied in 25 kg drums, ready for easy handling and storage. |
| Container Loading (20′ FCL) | XP-321W is packed in drums and loaded into a 20′ FCL, with secure stowage for safe, efficient transport. |
| Shipping | XP-321W ships in sealed drums or totes, protected from extreme temperatures and moisture. Non-hazardous per DOT, but use precaution against spills. Ensure upright handling, avoid prolonged UV exposure, and store in ventilated areas away from incompatible oxidizers. Standard ground freight applies; container integrity verified pre-shipment. |
| Storage | Store XP-321W in a tightly sealed container in a cool, dry, well-ventilated area, away from direct sunlight, heat sources, and strong oxidants. Recommended storage temperature is 5–35°C; protect from freezing. Avoid moisture contamination. Under these conditions, the product remains stable for up to one year from date of manufacture. |
| Shelf Life | Shelf life is typically 12 months from production date when stored unopened in a cool, dry place. |
In waterborne architectural matte formulations based on styrene-acrylic or vinyl acetate-ethylene copolymer binders with calcium carbonate and kaolin extenders at combined filler loadings of 38–52 wt% of total wet paint, air entrainment during high-speed pigment dispersion is not a cosmetic inconvenience but a viscosity-control variable that shifts Stormer readings and obscures the true end point of thickener adjustment. XP-321W is post-added at 0.10–0.25 wt% of total batch, typically split as 50% into the grind phase before the Cowles blade reaches 15–20 m/s tip speed and the remainder during letdown below 8 m/s, because the polyether-modified siloxane backbone must survive shear history without forming persistent micelles that later produce cratering in low-gloss films. For EU and North American distribution, the finished coating is evaluated under ISO 2811-1:2016 for density, ISO 1524:2013 for grind fineness, ASTM D562-10 for Stormer viscosity, and ASTM D4400-18 for sag resistance; for the Chinese domestic decorative market, GB 18582-2020 governs residual VOC and hazardous substance limits, while REACH Annex XVII substance restrictions apply at the chemical formulation level. Production-scale batch records show that foam-related pump cavitation in 1,000–5,000 L dispersers is most likely when pigment paste temperature exceeds 45 °C, a condition under which the quick-deaerating fraction of XP-321W is consumed within the first 10–15 min and a second addition is required at the letdown stage to maintain air release through filling. Over-addition above 0.5 wt% is avoided because it reduces intercoat adhesion as measured by ASTM D3359-17 cross-cut and can depress gloss in satin finishes to an observable degree. The terminal product types are interior matt wall paints, ceiling paints, and exterior masonry coatings applied by roller or airless spray.
Waterborne 1K acrylic-urethane direct-to-metal topcoats and 2K epoxy primers require air release at two distinct stages: during predispersion of zinc phosphate or calcium ion-exchanged silica pigments with a high-speed disperser, and during line-side circulation for airless spray, where piston-pump return lines repeatedly shear the defoamer. XP-321W is charged at 0.20–0.40 wt% based on total liquid coating; for high-PVC primers at 35–42% pigment volume concentration, the higher value is applied before the disperser reaches 18 m/s tip speed, while the lower value is post-added after letdown viscosity has been adjusted with associative polyurethane thickeners. Compliance texts include ISO 12944-5:2019 for protective paint systems in atmospheric environments, EC 1907/2006 REACH substance registration and safety data sheet provisions, ASTM D4541-17 pull-off adhesion, and ASTM B117-19 salt spray, the latter confirming that defoamer residues at the coating-substrate interface do not create adhesion-inhibiting monolayers. The downstream production process involves predispersion, bead milling to Hegman 5–6, letdown, and final airless spray application at 12–18 MPa fluid pressure through 0.28–0.38 mm tungsten carbide tips; production-line data indicate that macrofoam in the spray pump is suppressed within 30 s of post-adding XP-321W, but microfoam entrained inside the milled paste requires longer residence time in the letdown tank. Operational boundaries include maintaining letdown temperature below 35 °C and avoiding direct premixture with strongly alkaline amine-based neutralizers above pH 9.0, which can destabilize the polysiloxane emulsification. The terminal product types are waterborne direct-to-metal topcoats, machinery primers, and anticorrosive single-coat finishes for steel fabrications.
In waterborne flexographic packaging inks based on acrylic solution resins, styrene-acrylic emulsions, and organic pigments, foam is generated at the return line of the enclosed doctor chamber on narrow- and wide-web presses, where ink pumping at 8–15 L/min across anilox roll speeds of 200–500 m/min can reduce viscosity at the nip and create print mottle. XP-321W is introduced at 0.30–0.60 wt% of the liquid ink during the final letdown step after the pigment concentrate has passed through a horizontal bead mill; addition before milling is avoided because the polyether-modified siloxane can coat grinding media and reduce grinding efficiency. The ink is processed by high-speed predispersion at 12–15 m/s, bead milling with 0.6–0.8 mm yttria-stabilized zirconia beads, and letdown with acrylic emulsion; viscosity is adjusted to 18–25 s on a DIN 4 cup at 23 °C per ISO 2431:2019. Compliance requirements for food-contact printed matter follow European Framework Regulation (EC) 1935/2004 and Commission Regulation (EC) 2023/2006 on Good Manufacturing Practice for food-contact materials; ink formulation components are screened against the EuPIA exclusion policy for printing inks and harmonized REACH restrictions, while Swiss Ordinance SR 817.023.21 applies where inks are placed on the Swiss market. The terminal product types include waterborne flexographic and gravure printing inks for surface-printed plastic films, coated papers, and metallized substrates; in gravure units, foam build-up in the ink pan at cylinder speeds above 150 m/min is the primary indicator that the defoamer charge must be increased to the upper limit.
Waterborne acrylic pressure-sensitive adhesives coated onto silicone release liners by reverse gravure or slot die at 18–30 g/m² dry coat weight are sensitive to microfoam entrained during polymer synthesis and transfer, because foam cells collapse in the drying tunnel and leave pinholes that reduce peel uniformity. XP-321W is post-added at 0.05–0.20 wt% of the wet adhesive compound and mixed under low shear at 3–5 m/s for not more than 10 min; higher addition rates above 0.3 wt% produce surface-tension gradients on the release liner and generate fisheye defects in the dried adhesive film. The production process begins with emulsion polymerization of the acrylic PSA, followed by neutralization with ammonia or sodium hydroxide to pH 7.0–8.5, blending with wetting agents, and coating on a silicone-coated polyester liner; drying is carried out in a multi-zone air flotation oven with zone temperatures from 80 °C to 120 °C at line speeds of 100–300 m/min. Adhesion testing uses PSTC-101 or ASTM D3330-18 for 180° peel on stainless steel panels, and loop tack according to ASTM D6195-03; the defoamer must not migrate to the adhesive surface and alter the peel-force envelope. Food packaging applications are assessed under FDA 21 CFR 175.105 for indirect food additives where the adhesive is separated from food by a functional barrier, and under REACH Article 33 communication duties for candidate list substances in the EU. Terminal product types are single- and double-coated waterborne acrylic adhesive tapes, sheeted PSA labels, and flexible packaging laminating adhesives.
In paper coating color containing 55–68 wt% solids and composed of kaolin, precipitated calcium carbonate, styrene-butadiene latex, starch, and optical brighteners, entrained air acts as a compressible phase that lowers blade pressure and causes skip coating, streaks, and binder migration after drying. XP-321W is dosed at 0.10–0.40 wt% on dry pigment mass, preferably into the predispersion tank before the pigment slurry passes through a deaerating screen; under blade coater operating speeds of 800–1,500 m/min, the defoamer must provide rapid bubble collapse without forming oily aggregates that block the 100–150 µm filter mesh. The production sequence includes pigment slurrying in a Cellier or similar batch disperser, wet grinding and screening, addition of latex and starch under low shear, and final coating application by blade or rod metering onto woodfree or recycled base paper. Relevant compliance texts include the EU Ecolabel for converted paper products, European Framework Regulation (EC) 1935/2004 for paper and board intended for food contact, FDA 21 CFR 176.170 and 176.180 for coated paper where the coating does not affect migration beyond specified extractive limits, and ISO 2470-1:2016 for brightness retention after aeration. Terminal product types are coated fine paper, coated paperboard for folding cartons, label face stock, and art paper grades for high-speed sheetfed printing; production records show that foam-related viscosity loss in high-solids coating color is most evident when blade coater speed exceeds 1,200 m/min, requiring the upper end of the addition range.
Waterborne joinery topcoats and pigmented wood finishes applied through curtain coaters are evaluated not only by foam knockdown but also by absence of surface craters, which become more severe when the defoamer coalesces into droplets exceeding 20–50 µm in the wet film. XP-321W is incorporated at 0.15–0.30 wt% of total topcoat formulation, generally predispersed in the letdown phase after the acrylic or polyurethane dispersion has been thickened with a polyurethane associative thickener to a flow time of 40–60 s per ISO 2431:2019 at 23 °C; the formulation is then filtered through a 50 µm bag to remove oversized defoamer droplets before entering the curtain coater head. The downstream process includes high-speed dispersion of pigments and matting silica to Hegman 5–6, letdown under low shear, two-stage filtration, and application by curtain coating at head heights of 15–25 cm onto wood panels; air is entrained as the falling curtain contacts the moving substrate, and residual microfoam must rupture before the coating gels. Compliance requirements include EN 71-3:2019 migration limits for heavy metals in toy-grade wood coatings, GB 18581-2020 limits for VOC and hazardous substances in woodware coatings for the China market, and ISO 2409:2020 cross-cut adhesion for internal quality control. Terminal product types are waterborne clear and pigmented wood joinery topcoats, kitchen cabinet finishes, and furniture lacquers.
In two-component polymer-cement waterproofing slurries where a waterborne acrylic or styrene-acrylic polymer dispersion is mixed with dry cement powder, quartz sand, and defoamer, air entrainment during job-site mixing reduces compactness and tensile strength after curing. XP-321W is pre-dispersed in the liquid polymer component at 0.10–0.30 wt% of the liquid component; when the liquid component is mixed with powder at a 1:1.5 to 1:3 powder-to-liquid ratio, the active defoamer level falls to 0.03–0.10 wt% of the total mixed slurry, which is sufficient to release air during 2–5 min of low-speed mixing with a 400–600 rpm drill mixer. Published data for XP-321W in this specific two-component configuration is limited; the stated addition range is derived from class-level technical guidance for polyether-modified silicone defoamers rather than from a controlled mill trial. The production process at the dry-mix plant is designed to avoid overdosing because excess silicone defoamer can reduce wetting of cement particles and generate pinholes at the membrane-substrate interface. Compliance for the Chinese domestic market follows GB/T 23445-2009 for polymer-modified cementitious waterproof coatings and GB/T 16777-2008 for tensile testing after air curing; for export, REACH Annex XVII and CLP classification of the polymer dispersion component apply, and ASTM D4541-17 is used for pull-off adhesion to concrete substrates. The terminal product types are two-component polymer-cement waterproofing membranes, balcony and bathroom waterproofing slurries, and exterior wall sealing compounds.
Waterborne pigment printing pastes for rotary screen application generate foam as the paste is pumped through squeegee chambers and returned to the screen feed at viscosities of 15–30 Pa·s at 1 s⁻¹; the foam leads to skipped print areas and decreased color yield on cotton, cotton-polyester, and cellulosic blends. XP-321W is added at 0.20–0.50 wt% of the ready-to-use print paste after the binder, thickener, and pigment dispersion have been combined, because post-addition after the high-shear mixing stage preserves the quick-break behavior needed at the print station. The downstream production process includes predispersion of pigment pastes, mixing with a synthetic thickener based on ammonium polyacrylate or acrylic acid copolymer, addition of a crosslinking binder, and application through rotary screens with mesh counts of 60–125 threads/cm at line speeds of 20–80 m/min, followed by drying at 120–150 °C and curing at 150–170 °C for 2–5 min. Compliance for printed textiles includes OEKO-TEX Standard 100 Annex 4 for residual chemical limits, ZDHC Manufacturing Restricted Substances List Level 3 for the wet processing supply chain, and REACH Annex XVII Entry 72 restrictions on CMR substances in textile articles; the defoamer component must not leave a hydrophobic residue that affects print adhesion after heat curing. The terminal product types are rotary-screen and flat-bed water-based pigment printed apparel fabrics, home textiles, and piece-dyed fabric overprints.
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XP-321W is classified as a quick-defoaming polyether-modified polysiloxane for waterborne systems. The product is supplied as an anhydrous, nonionic liquid whose siloxane backbone is modified with pendant polyether chains. The molecular design reduces dynamic air/liquid interface tension while maintaining sufficient water compatibility to avoid the craters and fisheyes commonly observed with unmodified polydimethylsiloxane fluids. Typical addition ranges from 0.1% to 0.5% by total formulation mass, with final loading determined by pigment volume concentration, resin hydrophobicity, surfactant load, and application rheology. In comparison with mineral oil and conventional silicone emulsions, the quick-defoaming character of XP-321W is expressed as a shorter interval between foam generation and film rupture in low-shear foam tests; however, this fast knockdown profile requires deliberate addition-point control in high-shear manufacturing because the same surface activity that accelerates bubble collapse can be partially lost when the product is over-emulsified through repeated rotor-stator passes.
Physical property data for XP-321W are generated under controlled laboratory conditions using ISO 2811-1 for density, ISO 3219 for dynamic viscosity, ISO 3251 for nonvolatile content, and ASTM E70 for pH of an aqueous dilution. The product exhibits a typical density of 1.01 g/cm³ to 1.04 g/cm³ at 25 °C, a Brookfield viscosity of 600 mPa·s to 1,400 mPa·s with spindle LV3 at 60 rpm, and a nonvolatile content not less than 98.0% after 2 h at 105 °C. A 1% dispersion in deionized water gives a pH in the range 6.0 to 8.0. The product is self-dispersing under low-shear agitation and does not require high-pressure homogenization for use in waterborne coatings; however, undiluted addition into highly acidic media with pH below 3.0 or alkaline media above 10.0 can accelerate siloxane hydrolysis and reduce defoaming longevity. Closed-cup flash point exceeds 100 °C under ISO 1523.
| Property | Test method | Typical lot value |
|---|---|---|
| Appearance | Visual | Slightly hazy, off-white to pale amber liquid |
| Density at 25 °C | ISO 2811-1 | 1.01–1.04 g/cm³ |
| Viscosity at 25 °C | ISO 3219, Brookfield LV3, 60 rpm | 600–1,400 mPa·s |
| Nonvolatile content | ISO 3251, 105 °C/2 h | ≥98.0% |
| pH, 1% in deionized water | ASTM E70 | 6.0–8.0 |
| Flash point | ISO 1523 | >100 °C |
| Water dispersibility | Internal method: 0.5% in deionized water, 300 rpm, 5 min | Stable dispersion, no visible oil separation after 24 h |
The primary performance distinction is interfacial behavior in the foam lamella. Unmodified polydimethylsiloxane lowers surface tension to approximately 20 mN/m to 21 mN/m and spreads aggressively on waterborne surfaces; this produces efficient foam rupture but also creates local surface tension gradients that can develop into craters when the material is not emulsified sufficiently. Mineral oil defoamers spread more slowly, are less efficient at low addition, and can contribute to surface tack or gloss reduction in waterborne film-forming systems. Polyether modification in XP-321W couples a siloxane segment with a hydrophilic polyether chain, producing a nonionic amphiphilic structure that partitions at the air/liquid interface. The polyether chains increase water compatibility and reduce the risk of macroscopic dewetting, while the siloxane backbone retains a low surface tension for rapid foam film drainage. Defoaming efficiency is ranked according to ASTM E2407, in which a sparged aqueous surfactant solution is defoamed and the collapse of the foam column is recorded; XP-321W is intended for rapid foam-height reduction rather than long-duration suppression in recirculating systems. Where long-term foam control is required, published data for this specific configuration is limited and the product should be evaluated in combination with a suitable foam-suppression grade.
Compared with conventional silicone emulsions, XP-321W contains no intentionally added water and therefore does not require freeze-thaw stabilizers or in-can biocides. In production-scale use, this anhydrous character reduces the risk of batch dilution and can improve storage stability under warehouse temperatures between 5 °C and 30 °C. The trade-off is that the undiluted product must be dispersed adequately into the aqueous phase; direct addition to a viscous paint base without agitation may produce local concentrations that exceed the compatibility threshold of the binder and cause surface defects.
In low-PVC waterborne acrylic and styrene-acrylic architectural coatings, the initial dosage window for XP-321W is 0.1% to 0.3%. High-PVC formulations containing flatting concentrates, coarse mineral fillers, or high surfactant levels may require 0.3% to 0.8% because foam generation accelerates with increasing total free surfactant and filler surface area. High-shear processing does not maintain the same defoaming activity as low-shear post-addition. On a production Cowles dissolver operating at 8 m/s tip speed, the product is most often split: 50% of the total dosage is added during the grind to control mill-base froth, and 50% is post-added during letdown under 300 rpm to 600 rpm paddle mixing. This split preserves a rapid-action fraction in the final formulation while limiting the portion that is exposed to high shear and possible over-emulsification. Over-emulsification reduces droplet size below the range needed for efficient foam-film penetration and can convert the defoamer into a foam stabilizer in some waterborne systems.
Rotor-stator homogenization, microfluidization, or repeated high-pressure pumping through 300 bar homogenizers is not recommended for the post-added portion; the resulting particle-size reduction may increase compatibility but decrease defoaming efficiency. The product should be added downstream of filtration where possible. In waterborne polyurethane dispersions with pH below 6.5, pre-dilution at 1:10 in water or in a compatible coalescing solvent before addition reduces localized pH shock and improves distribution at low dosage.
In clear waterborne acrylic lacquers and one-component PUD topcoats, XP-321W requires a lower dosage window of 0.05% to 0.2%. Overdosing above 0.3% may generate a secondary haze because the amphiphilic copolymer is not fully soluble in the dry film and can scatter visible light when trapped in the matrix. The haze threshold is measured on 200 µm wet-film drawdowns over black glass after 24 h drying at 23 °C and 50% relative humidity, with clarity comparison under diffuse light and spectrophotometric haze measurement according to ASTM D1003. When haze exceeds the control panel by more than 3%, the formulation should be adjusted by reducing dosage or by pre-diluting the product in the main coalescent before addition.
Microfoam release in waterborne wood coatings is evaluated by forced drying of 150 µm wet-film drawdowns at 60 °C for 30 min, followed by cross-section inspection for pinhole count. In a high-tannin oak coating system, XP-321W at 0.10% reduced pinhole formation relative to a mineral oil control, whereas an unmodified PDMS grade at the same percentage produced visible craters under oblique light. The polyether-modified product therefore occupies a narrow processing window in clear finishes: sufficient surface activity to rupture bubbles during drying, but insufficient incompatibility to create persistent optical defects in the final film.
For waterborne flexographic and gravure inks with viscosity below 200 mPa·s, foam is generated continuously by pump circulation and anilox roller entrainment. XP-321W can be added directly to the ink letdown tank at 0.05% to 0.2%; the polyether structure assists water dispersibility in low-viscosity media, and the quick collapse mode reduces foam-induced flooding and print mottle. However, because the product is a knockdown defoamer rather than a persistent deaerator, high-speed press trials should include a foam-suppression maintenance program if the ink remains in a recirculation loop for more than 4 h. The product is not a wetting agent; it should not be used to compensate for poor pigment dispersion or substrate wetting defects.
In waterborne pressure-sensitive adhesive lattices, foam is trapped during transfer and coating operations. XP-321W added at 0.05% to 0.15% reduces macrofoam without lowering peel adhesion in standard tape tests when the product is fully dispersed. The lower dosage is necessary because excess surface-active material can migrate to the adhesive interface and affect wet-out on low-energy substrates. Peel performance is measured according to ASTM D3330 or ISO 29862, depending on the substrate; no adhesion loss is observed at the recommended dosage, but published data for this specific configuration is limited. If blocking or haze on clear films occurs, the product should be diluted in a compatible coalescent before addition and incorporated below 300 rpm.
In high-film-thickness elastomeric waterproofing coatings based on acrylic or styrene-acrylic emulsions, foam entrapment becomes visible as pinholes after squeegee application at 800 µm wet-film thickness. XP-321W can be incorporated into the grind at 0.2% to 0.4% to control mill-base aeration; a post-add of 0.05% to 0.1% before packaging further reduces air released during drum-off. The quick-defoaming profile is most relevant to machine-applied systems where foam must collapse before the surface skins. However, when the coating is spray-applied through airless units operating above 180 bar, the product may require a companion high-persistence silicone emulsion because rapid knockdown alone may not control foam generated continuously in the spray pump reservoir.
XP-321W is supplied in 25 kg pails and 200 kg drums. Store in unopened containers at 5 °C to 30 °C, protected from direct sunlight and moisture ingress. Before sampling, the material should be homogenized by low-speed rolling or paddle stirring because slight phase separation can occur after prolonged static storage; do not use high-speed dispersion to reincorporate separated layers. Shelf life in original sealed packaging is 24 months from date of production. Do not store in contact with strong oxidizers, strong acids, or strong bases. If frozen, allow the product to reach 20 °C to 25 °C and re-mix gently before use; freeze-thaw cycling beyond 3 cycles is not recommended without a qualification trial. These storage and handling constraints are derived from standard industrial practice for polyether-modified siloxane antifoams and are not intended to replace formulation-specific stability testing.
