In oil-based and solvent-free systems such as epoxy floor coatings, screen-printing inks, UV-curable inks, and unsaturated polyester, mechanical stirring, pump circulation, high-speed coating, and troweling trap air into high-viscosity resins, causing microbubbles, pinholes, craters, and fish eyes. Conventional solvent-bearing defoamers introduce volatile carriers into solvent-free formulas, increasing VOC and potentially inducing curing bubbles; pure polyether types spread slowly in solvent-free epoxy with lagged knock-down; common aqueous emulsions are water-compatible but unsuitable for oily high-solids resins. With self-leveling flooring, thick-film UV, high-pigment screen ink, and unsaturated polyester molding demanding "100% active, zero solvent, hydrophobic-particle fast break, low-dose long antifoam", finding a "translucent-to-turbid, high-nonvolatile, mid-low viscosity, thixotropy-controllable" oil/solvent-free defoamer has become a key formulation issue. Addressing this, Anhui IOTA Silicone Oil Co., Ltd. officially launches Defoamer IOTA-29300. Characterized by "hydrophobic-particle-containing polysiloxane compound; 100% solids; appearance semi-transparent to turbid liquid; non-volatile (150℃/3h) >98%; viscosity 200–500 mPa·s; dosage 0.05–1%; 25L/200L plastic drum (customizable); non-hazardous; cool dry sealed, 12-month shelf", backed by "hydrophobic-particle bubble break + polysiloxane low-tension spread + 100% active zero solvent", it serves as the "particle choice" for oil-based/solvent-free defoaming, achieving the leap from "solvent defoamer introduces VOC, pure polyether lags" to "hydrophobic-particle polysiloxane high-solids bubble break new clarity". System Positioning: Hydrophobic-Particle Polysiloxane vs. Solvent Defoamer/Pure Polyether/Aqueous Emulsion IOTA-29300 belongs to oil-based solvent-free silicone defoamer concentrate, distinct from solvent-borne silicone oil, pure polyether, and oil-in-water emulsion. Solvent-borne breaks fast but carries volatile diluents into solvent-free epoxy/UV, causing curing bubbles and yellowing; pure polyether spreads slowly in solvent-free high-viscosity systems with delayed microbubble knockdown; aqueous emulsion uses water/emulsifier and shows poor compatibility in oily resins. IOTA-29300 uses polysiloxane as continuous phase and hydrophobic particles as bubble-break active sites, 100% solids with no extra solvent, balancing oil compatibility and solvent-free safety. Molecular Architecture: Polysiloxane Continuous Phase + Hydrophobic Particles + 100% Active Zero Solvent The core design of IOTA-29300 comes from the "hydrophobic-particle-containing polysiloxane compound" non-aqueous defoamer architecture:

• Polysiloxane Low-Tension Spread: The polysiloxane backbone has low surface tension and spreads readily on resin lamellae, migrating to the air-liquid interface, displacing surfactants, and weakening bubble films for break and post-spread antifoam.
• Hydrophobic-Particle Break Point: Hydrophobic solid microparticles create local weaknesses in bubble films, promoting drainage and film-wall destabilization, especially for microbubbles in high-viscosity systems; particles and polysiloxane act synergistically for faster knockdown than silicone oil alone.
• 100% Solids Zero Solvent: Non-volatile 150℃/3h >98%, no extra water or organic solvent carrier, avoiding VOC, moisture, and curing bubbles in solvent-free epoxy/UV, and reducing shipped inactive load.
• Mid-Low Viscosity Thixotrope: Viscosity 200–500 mPa·s eases pumping and dosing; product is thixotropic, hydrophobic particles may settle or viscosity may rise after long standing or at low temperature, which is normal rheology — stir well before use to restore dosing consistency.

Performance Leap: From "Solvent Induces Bubbles" to "High-Solids Particle Fast Break and Antifoam" Introducing IOTA-29300 brings the following improvements:

• Fast Microbubble Break: Hydrophobic-particle plus polysiloxane dual mechanism quickly collapses microbubbles in epoxy self-leveling, thick-film UV, and high-pigment screen ink, reducing pinholes, fish eyes, and sand holes.
• Long Antifoam: Silicone continuous phase forms a low-tension film at the air-liquid interface, suppressing regenerated foam after repeated stirring and lowering repeat addition.
• Zero-Solvent Safety: 100% active, non-volatile >98%, no extra solvent/water for solvent-free epoxy/UV, reducing curing porosity and yellowing.
• Low-Dose Economy: 0.05–1% of total formula is effective; high-active concentrate reduces additive cost and storage volume.
• Oil Compatibility: Designed for epoxy, unsaturated polyester, solvent/screen and UV inks; for transparent systems, run compatibility trials to control oil bleed.

Application Penetration: From Epoxy Self-Leveling to Unsaturated Polyester Molding IOTA-29300 covers oil-based/solvent-free scenarios:

• Epoxy Floor Coatings: Defoams during mixing and troweling of solvent-free/high-solids self-leveling, reducing trowel-trail bubbles and surface pinholes for mirror smoothness.
• Screen-Printing Inks: Removes bubbles from ink tank stirring and squeegee entrainment, avoiding white spots, sand holes, and missing dots for sharper lines.
• UV-Curable Inks: Breaks foam in UV formulas without markedly affecting cure speed and adhesion, reducing cured-film craters and fish eyes.
• Unsaturated Polyester Systems: For casting, molding, and gel coat, removes mixing/coating microbubbles and improves surface density and mechanical consistency.
• Other Oil/High-Viscosity Systems: Usable as defoamer reserve for oil coatings and solvent-free adhesives; run dilution and compatibility trials by resin polarity.

IOTA Technical Guide: Low Dose Pre-Dilute, Stir and Use Soon

• Application: Add 0.05–1% of total formula; for high-viscosity epoxy self-leveling start from 0.1–0.5%, screen/UV 0.05–0.3%, unsaturated polyester 0.1–0.5% as trial baselines. Because active content is high, pre-dilute to 10% with aliphatic or aromatic solvent before addition; because hydrophobic particles tend to settle, use the dilution soon after preparation.
• Addition Timing: Add before milling or stirring for dispersion and antifoam; for finished paint/ink post-addition, use low-speed stirring. For transparent clearcoat and high-gloss systems, run compatibility tests first for oil bleed, haze, and craters.
• Thixotropy Handling: Viscosity rise after long standing or at low temperature is normal thixotropic/settling behavior; stir the whole drum uniformly before use; if stored cold for long periods, move to ambient temperature then stir thoroughly.
• ⚠️ Taboo: Shipped/stored as non-hazardous, but store cool dry, sealed, away from acid/alkali and ignition/heat sources; do not blend blindly with incompatible solvents; beyond 12-month shelf life, retest non-volatile, viscosity, and defoaming before use; wash skin after contact, avoid prolonged direct exposure.
• Storage: 25L/200L plastic drum (customizable); cool, dry, sealed; non-hazard transport; 12-month shelf life. Unlike IOTA 1831 (paper pulping aqueous defoamer, white microemulsion, nonionic) which is water/alkali pulp breaking, IOTA-29300 is oil/solvent-free high-solids microbubble breaking.

Industry Insight: The core value of oil/solvent-free defoamer lies in "hydrophobic particles for fast microbreak, polysiloxane for low-tension antifoam, 100% solids for zero-solvent safety". IOTA-29300, with "hydrophobic-particle polysiloxane, 100% solids, non-volatile >98%, viscosity 200–500 mPa·s, 0.05–1%, 25/200L plastic drum, non-hazard 12 months" hard parameters, fills the particle-level microbubble link of domestic solvent-free epoxy flooring, screen, UV, and unsaturated polyester. For flooring makers and ink formulators, it upgrades along the path of "solvent silicone oil → pure polyether → hydrophobic-particle polysiloxane high-solids", reducing VOC and curing-porosity risk while raising film flatness and long-antifoam premium.