In alkaline pulping, washing, and pulp bleaching, foam is a persistent problem restricting washing efficiency, sizing uniformity, and paper quality. Fatty acids and resin acids in raw materials react with NaOH and Na₂S to form soaps, residual alkali, and alkali lignin — all foaming substances. Cellulosic polymers stabilize foam, while stock conveying and mixing entrain air, creating massive stable foam. Ordinary mineral oil defoamers saponify and fail under strong alkali and high temperature; conventional silicone emulsions demulsify and float in alkaline black liquor, contaminating pulp and affecting sizing and strength. With alkaline, bamboo, and bagasse pulping lines demanding "alkali resistance, fast defoaming, low dosage, no secondary pollution", finding a "modified PDMS-based, specially alkali-resistant emulsified, ≤100℃ heat resistant, centrifugally stable" pulping defoamer has become a core issue for papermaking auxiliaries. Addressing this, Anhui IOTA Silicone Oil Co., Ltd. officially launches Papermaking Pulping Defoamer IOTA 1831. Characterized by "modified PDMS as main body, with dispersing aids, special alkali-resistant emulsifier, and siloxane addition product; appearance white microemulsion; nonionic; pH 7±1; active content ≥10%; centrifugal stability 3000 rpm × 15 min, no layering/no precipitate; viscosity 500–1500 cSt; heat resistance ≤100℃", backed by "modified PDMS + special alkali-resistant emulsification + lignin-targeted bubble breaking + no secondary pollution", it serves as the "clean-pulp choice" for alkaline pulping, achieving the leap from "conventional silicone demulsifying and polluting in alkali" to "alkali-resistant composite rapid clean pulping". System Positioning: Alkali-Resistant Composite Defoamer vs. Mineral Oil/Conventional Silicone IOTA 1831 belongs to the modified PDMS composite pulping defoamer family, distinct from mineral oil and conventional anionic/nonionic silicone emulsions. Mineral oil saponifies, disperses poorly, and leaves oil spots under strong alkali and high temperature. Conventional emulsions with ordinary emulsifiers hydrolyze and demulsify in alkaline black liquor, releasing silicone oil that floats and contaminates pulp. IOTA 1831 uses modified PDMS as the active core, paired with special alkali-resistant emulsifier and siloxane addition product, keeping the emulsion stably dispersed in alkaline stock without demulsification, floating, or secondary pollution. Molecular Architecture: Modified PDMS + Special Alkali-Resistant Emulsifier + Siloxane Adduct The core design of IOTA 1831 comes from modified PDMS composite defoamer structure:

• Modified PDMS Main Body: Modified siloxane as the defoaming active core, with surface tension far below water and black liquor, rapidly spreading on soap foam lamellae to thin and rupture films. The modified structure improves pulp compatibility, reducing craters and oil spots.
• Special Alkali-Resistant Emulsifier: The alkali-resistant emulsification system keeps the white microemulsion stable in strongly alkaline stock (broad pH) without hydrolysis or demulsification; centrifugal 3000 rpm × 15 min shows no layering or precipitate.
• Siloxane Addition Product: Siloxane adduct synergizes with dispersing aids to target and rapidly break foam from lignin, resin acid soaps, and surfactants, boosting speed and persistence.
• Heat Resistance ≤100℃: Adapted to high-temperature washing stages, maintaining activity below 100℃ without decay.

Performance Leap: From "Strong-Alkali Failure" to "Alkali-Resistant Rapid Defoaming" Introducing IOTA 1831 brings the following improvements:

• Outstanding Alkali Resistance: Specially alkali-resistant emulsification runs stably in alkaline pulping and black-liquor washing without demulsification or floating.
• Rapid Defoaming: Quickly eliminates foam caused by lignin and other surfactants; especially effective in pulping, washing, and paper sizing.
• Low Dosage: Recommended initial dosing 0.08–0.5 kg per ton pulp; expected 0.05–0.3 kg per ton air-dried pulp.
• No Secondary Pollution: Modified PDMS system introduces no persistent pollutants, with no negative impact on pulp or paper.
• Centrifugally Stable: 3000 rpm × 15 min, no layering, no precipitate — stable during storage and use.
• Economical: Fast defoaming, low dosage, affordable, reducing overall cost.
• Heat Applicable: Heat resistance ≤100℃ covers mainstream pulping and washing stages.

Application Penetration: From Alkaline Cooking to Black Liquor Washing IOTA 1831 covers the full papermaking pulping process:

• Alkaline Pulping: Foam control in NaOH/Na₂S cooking stages.
• Washing/Bleaching: Foam suppression in pulp washing, bleach, and screening stages.
• Bamboo/Bagasse Pulp: Dedicated for plant-fiber pulping, adapting to non-wood pulp systems.
• Black Liquor Washing Line: Foam control before alkali recovery.
• Paper Sizing: Defoaming in sizing stages, reducing pinholes and formation defects.
• Water Treatment: Foam control in pulp industry wastewater treatment.

IOTA Technical Guide: Drip Feed, Dilute, Optimize Drip Point

• Application: Add directly via dosing pump to the foaming system. Recommended initial 0.08–0.5 kg per ton pulp; expected 0.05–0.3 kg per ton air-dried pulp. Drip point is determined by production conditions and optimized toward "lower dosage".
• Dilution: To control dosing, dilute by slowly adding water to the emulsion with gentle mixing. Use diluted defoamer promptly, generally within 12 hours.
• ⚠️ Taboo: Diluent is water — use deionized water to avoid flocculation from hard-water ions. Use diluted product within 12 hours to prevent settling. Reseal after use to prevent skinning. Heat resistance ≤100℃; avoid prolonged overheating causing activity decay. Centrifugal test at 3000 rpm × 15 min; avoid prolonged high-shear mixing that may cause demulsification.
• Storage: 50kg plastic drum or 200kg iron drum (or per customer request); store in a cool dry place, avoid direct sunlight; shelf life ≤1 year; transport as general goods. Unlike IOTA 2303 (5–40℃/6 months/non-hazardous), IOTA 1831 follows cool-dry, ≤1 year, general-goods transport guidelines.

Industry Insight: The core value of pulping defoamer lies not in "more silicone is better", but in "modified PDMS for rapid bubble breaking, special alkali-resistant emulsifier for alkaline stability, siloxane adduct for lignin targeting, centrifugal stability for pollution-free operation". IOTA 1831, with "modified PDMS + special alkali-resistant emulsifier + siloxane addition product; white microemulsion; nonionic; pH 7±1; active ≥10%; centrifugally stable; viscosity 500–1500 cSt; heat ≤100℃; 0.05–0.3 kg per ton air-dried pulp" hard parameters, fills the clean-pulp base link of domestic alkali-resistant composite defoamers in alkaline pulping, bamboo/bagasse pulp, and black-liquor washing lines. For papermaking auxiliary manufacturers, it upgrades pulp washing efficiency and paper formation premium along the path of "mineral oil defoamer → conventional silicone emulsion → modified PDMS alkali-resistant composite defoamer".