In reactive modification of polyurethane, polyester, and epoxy resins, plus hydrophilic lubrication and mold release, formulators are often stuck because "blended silicone migrates, silanol-grafted silicone hydrolyzes back, and low-surface-energy siloxane segments are hard to embed permanently into the organic backbone". Ordinary methyl silicone oil physically mixed with organic resin has a narrow compatibility window and tends to oil off, turn tacky, and lose handle after storage or heating; conventional silanol-terminated polysiloxane often enters the network through Si–O–C when reacting with isocyanate, carboxyl, anhydride, or epoxy, and that linkage can retro-hydrolyze under humidity/heat, causing silicone bleed, coating haze, and softness decay; common polyether soft segments add flexibility but lack PDMS low surface energy, chain flexibility, and weathering. With waterborne PU synthetic leather, electronic epoxy encapsulation, and high-performance polyester coatings demanding "chemical embedding, low migration, hydrolysis resistance, hydrophilic lubrication", finding a "bis carbon-hydroxyl, Si–C anchored, low-viscosity dispersible, hydrophilic-lube/release capable" reactive silicone has become a key resin-modifier issue. Addressing this, Anhui IOTA Silicone Oil Co., Ltd. officially launches Carbinol Silicone Oil IOTA 28300. Characterized by "carbinol-terminated polydimethylsiloxane; α,ω-Bis(3-(2-hydroxyethoxy)propyl)polydimethylsiloxane; code IOTA 28300; colorless transparent oily liquid; density 0.972–0.982 g/cm³ at 25℃; hydroxyl value 1.60–2.00 mmol/g; viscosity 30–50 mm²/s at 25℃; volatiles ≤2.00% (typical properties not quality specifications); C–OH reacts with isocyanate, carboxyl, anhydride, epoxy to introduce polysiloxane via Si–C into organic polymers for PU/polyester/epoxy modification, better hydrolysis stability than Si–OH→Si–O–C; also hydrophilic lubricant/release; 25L/200L internally coated iron drum, 20kg/195kg net; room-temperature sealed 12 months from production; follow MSDS/label and PPE", backed by "bis carbon-hydroxyl high reactivity + Si–C anti-hydrolysis anchoring + PDMS low-energy flexible chain + low-viscosity homogeneous dispersion", it serves as the "coupling choice" for reactive resin modification, achieving the leap from "physically blended oil migrates, silanol hydrolyzes back in humidity" to "carbon-hydroxyl silicone bonding, permanent Si–C new coupling". System Positioning: Bis Carbinol Si–C Silicone vs. Silanol Silicone/Methyl Oil/Polyether IOTA 28300 belongs to α,ω-bis(3-(2-hydroxyethoxy)propyl) PDMS, distinct from silanol-terminated polysiloxane, non-functional methyl silicone oil, and ordinary polyether modifier. Silanol-terminated oil condenses/adds via Si–OH, often forming Si–O–C, which can retro-hydrolyze and self-condense under humidity/heat; non-functional methyl oil only lubricates physically without grafting or copolymerization and migrates long term; ordinary polyether softens and adds hydrophilicity but lacks PDMS low surface energy, flexibility, and weathering. IOTA 28300 hangs hydroxyls at the end of propoxy-ethoxy carbon chains connected to the siloxane backbone through Si–C; when reacting with isocyanate/carboxyl/anhydride/epoxy, the active ends are fixed by carbon–silicon bonds rather than moisture-sensitive Si–O–C, retaining bis primary-alcohol reactivity while reducing retro-hydrolysis after embedding. Molecular Architecture: PDMS Backbone + Bis Hydroxyethoxypropyl + Si–C Fixed Anchor The core design of IOTA 28300 comes from a bis-carbinol polysiloxane structure:

• PDMS Flexible Low-Energy Backbone： The central polydimethylsiloxane supplies low surface energy, low glass-transition tendency, flexible lubrication, and weathering resistance; once introduced into organic resins it reduces friction, improves slip, and buffers thermal stress, with exact reduction by resin type and addition ratio trial.
• Bis Terminal Primary Carbinol： Each end carries 3-(2-hydroxyethoxy)propyl with terminal primary –CH₂OH, more reactive toward isocyanate, carboxyl, anhydride, and epoxy than secondary/phenolic OH; hydroxyl value 1.60–2.00 mmol/g characterizes total bis-terminal hydroxyls and allows use as a macromolecular diol in PU chain extension or as an opening/esterification/amidation active end for polyester, epoxy, and anhydride systems.
• Si–C Anti-Hydrolysis Anchor： The active hydroxyls connect to the siloxane through propyl Si–C bonds; after reaction with organic groups the polysiloxane segment is welded into the main network via Si–C, giving lower retro-hydrolysis risk and less silicone migration than Si–OH→Si–O–C routes.
• Hydroxyethoxy Hydrophilic Tuning： The terminal oxyethylene imparts partial hydrophilicity and water-dispersible tendency, enabling hydrophilic lubrication and hydrophilic release interfaces rather than pure hydrophobic oil; exact hydrophilic level, dilution medium, and dry/wet slip by system trial.
• Low-Viscosity Dispersion： Viscosity 30–50 mm²/s at 25℃, density about 0.97–0.98 g/cm³, colorless transparent oily liquid, easy for manual or low-shear mixing into prepolymers, resin components, and solvent/water media; volatiles ≤2.00% reduce processing bubbles and odor, yet compatibility with any specific curing system still requires trial.

Performance Leap: From "Blended Migration" to "Si–C Copolymer New Coupling" Introducing IOTA 28300 brings improvements in reactive modification:

• Chemical Embedding, Low Migration： Bis C–OH bonds with resin functionalities and Si–C fixes the siloxane segment into the main chain/network; versus physical blending it reduces oil bleed, exudation, and surface tack-back; long-term slip and handle decay more slowly (actual humidity-cycle by end-product aging).
• Better Hydrolysis Stability： Compared with Si–OH→Si–O–C incorporation, Si–C anchoring has lower probability of retro-hydrolysis under humidity/heat, suiting moisture-sensitive, long-term-wet PU/epoxy/polyester parts; absolute non-hydrolysis is not claimed—run accelerated immersion/humid-heat evaluation per condition.
• Low Surface Energy Slip： The PDMS chain lowers surface energy and improves slip, anti-block, and release in coatings, elastomers, and adhesives; versus unmodified resin it reduces friction, but absolute coefficient is not supplied and not fabricated.
• Flexibility and Thermal-Stress Buffer： Silicone flexible segments absorb epoxy curing shrinkage stress and improve PU/polyester low-temperature flexibility; for brittle epoxy they reduce internal stress and microcracking, with exact toughening rate by formulation trial.
• Hydrophilic Lube/Release Dual Use： Terminal hydroxyethoxy gives hydrophilic tendency; used neat or diluted as hydrophilic lubrication and metal/plastic/rubber release; more water-process friendly than pure methyl oil, yet water-dilution ratio and emulsifier by processing medium.

Application Penetration: From PU Soft Segment to Epoxy Encapsulation IOTA 28300 covers three resin modifications plus two interface treatments:

• Polyurethane Modification： As macromolecular diol in prepolymer/chain extension; waterborne or solvent PU synthetic leather, coatings, and elastomers receive siloxane segments for softer slip, anti-tack, and weathering; with MDI/TDI/polyether polyols run small trials on reaction rate and storage stability first.
• Polyester Modification： Polycondensation with diacids/anhydrides or grafting onto carboxyl-terminated polyester to balance hardness/toughness and surface slip; food/medical polyester requires migration and regulatory trials, not assumed compliant.
• Epoxy Modification： Blend with epoxy/amine curing via hydroxyl participation or as flexible segmented copolymer to lower internal stress, add flexibility, and improve release; electronic encapsulation, coatings, and adhesives require extra screening for insulation, volume resistivity, and yellowing.
• Hydrophilic Lubrication： Metal working, fiber/film surfaces, and precision parts for temporary lubrication; cleaner and less dusty than pure oil, with extreme-pressure life and service duration by workload trial.
• Reactive Release： Plastic, rubber, and composite molds as inner hydrophilic silicone film; more chemically compatible and less migratory than external methyl oil, yet wash-free decision by post-molding process.

IOTA Technical Guide: Bis C–OH Grafting, Si–C Avoid Humid Retro-Cleavage

• Dosage and Addition： Supplied hydroxyl value 1.60–2.00 mmol/g, viscosity 30–50 mm²/s; calculate bis-terminal hydroxyl contribution by target resin equivalents, then set IOTA 28300 mass ratio to resin/prepolymer. No recommended addition is supplied; do not adopt third-party 1–6% marketing values. Start with small gradients for filming/curing/storage, then scale.
• Reaction Hookup： In PU line, add with isocyanate prepolymer or post-chain-extension, monitor NCO/OH equivalence and gel time; in polyester line, esterify/condense with carboxyl/anhydride; in epoxy line, premix with epoxy then cure by amine/anhydride, or half-esterify with carboxylic/anhydride before cocure; catalysts, temperature, and vacuum by host formula.
• Hydrophilic Lube/Release Preparation： Neat oil can be applied directly; for water phase, pre-emulsify with minor co-solvent or high shear, then full-water dilute—terminal hydroxyethoxy gives only partial hydrophilicity, not full water solubility. No emulsifier or dilution ratio supplied, so none fabricated.
• ⚠️ Taboo： Store room-temperature sealed; avoid prolonged high heat that raises volatiles/oxidation and avoid long-term moisture ingress that contaminates the drum (C–OH is Si–C fixed, yet storage remains sealed and moisture-controlled); 25L/200L internally coated iron drum, reseal after use. Follow MSDS/label for gloves, goggles, and ventilation; run compatibility trials before blending with strong acid/base/oxidizer or unknown highly active curatives. Beyond 12 months from production, retest before use.
• Storage： 25L or 200L internally coated iron drum, 20kg or 195kg net; room-temperature sealed, 12 months from production date. Unlike IOTA 1318 (leather nonionic hydrophobic), IOTA 1325 (fabric cationic wash-durable), IOTA 2606 (fluoro-silicone anionic slick/anti-soil), IOTA 1302 (hydrogen nonionic breathable waterproof), IOTA 240 (high-temperature silicone emulsion), IOTA EMUL 872 (high-solid slightly anionic general release), IOTA 2615 (wig cationic soft-comb), IOTA 28300 is bis-carbinol Si–C reactive silicone—1318 for leather surface, 1325 for fabric wash durability, 2606 for coating slick/anti-soil, 1302 for fiber/building breathable hydrophobic, 240 for hot lube, 872 for multi-line release, 2615 for wig comb, 28300 for PU/polyester/epoxy covalent coupling and hydrophilic lube/release.

Industry Insight： The core value of reactive carbinol silicone lies in "bis primary hydroxyl for high reactivity, propyl Si–C for hydrolysis resistance, PDMS for low-energy flexibility, hydroxyethoxy for hydrophilic interface". IOTA 28300, with "carbinol-terminated PDMS, α,ω-Bis(3-(2-hydroxyethoxy)propyl)polydimethylsiloxane, colorless transparent oily, density 0.972–0.982 at 25℃, OH 1.60–2.00 mmol/g, viscosity 30–50 mm²/s, volatiles ≤2.00% (typical, non-quality), C–OH with NCO/COOH/anhydride/epoxy via Si–C, PU/polyester/epoxy modification, hydrophilic lube/release, 25/200L internally coated iron drum 20/195kg, room-temperature sealed 12 months", fills the bis-carbinol Si–C node between physical methyl-oil migration, silanol Si–O–C humid retro-cleavage, and polyether lacking siloxane low energy. For PU synthetic leather, polyester coating, epoxy encapsulation, and hydrophilic lube/release formulators, it upgrades along "methyl silicone physical blend → silanol Si–O–C graft → bis carbinol Si–C copolymer", reducing migration bleed and humid-hydrolysis risk while raising integrated premium of slip, flexibility, weathering, and anti-tack coupling.