Epoxidized linseed oil (ELO) is a bio-based functionalized oil obtained by epoxidizing the polyunsaturated double bonds in linseed oil with peroxy acids. It is characterized by a high epoxy value, low volatility, and good compatibility. Leveraging its renewable source and reactivity, ELO plays multiple roles in polymer modification, coatings, adhesives, and lubricant formulations, balancing performance and sustainability.
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PVC Stabilization and Plasticization: ELO is commonly used as a secondary plasticizer and heat stabilizer for PVC. The epoxy groups can capture HCl generated during thermal degradation, thereby improving heat resistance and resistance to light aging, while reducing the glass transition temperature of the material, enhancing flexibility and impact resistance. It is used in applications such as cable materials, hoses, flooring, and (subject to regulations) food contact seals.
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Rubber and Blend Compatibility: In rubbers such as SBR and NBR, ELO improves compounding processability and filler dispersion, and enhances weathering and oil resistance. Its polar functional groups can also act as compatibilizers, strengthening interfacial adhesion in immiscible blends such as PLA/rubber and starch/polyolefins, improving the balance of mechanical properties and toughness.
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Coatings, Inks, and UV Curing: ELO can act as a reactive diluent and crosslinking monomer in cationic/UV curing systems, improving coating adhesion, chemical resistance, and corrosion resistance, while helping to reduce VOCs. In inks, it also functions in pigment wetting and rheology control.
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Adhesives and Sealants: By curing with amines or anhydrides, ELO can form a bio-based epoxy network, used in woodworking adhesives, structural adhesives, and construction sealants, providing good flexibility and durable bonding, while reducing the environmental footprint of traditional solvent-based systems.
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Composites and Resin Matrices: ELO, as a green epoxy resin precursor, is suitable for natural fiber composites (such as flax fiber reinforced materials), achieving a high bio-based content and excellent interfacial bonding, balancing strength, toughness, and lightweighting.
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Lubrication and Metalworking Fluids: As an extreme pressure/anti-wear and antioxidant additive, ELO enhances the load-carrying capacity of lubricant films and improves biodegradability. It is necessary to pay attention to compatibility with base oils, control acidic impurities, and ensure storage stability.
Compared to the more common epoxidized soybean oil (ESBO), ELO typically has a higher epoxy value and stronger reactivity, giving better plasticization and crosslinking efficiency; however, its viscosity is higher, and long-term color stability and oxidation stability need to be guaranteed through formulation synergies (such as using it in combination with hindered phenols and phosphites). Overall, ELO, with its renewable source, multifunctional reactivity, and regulatory friendliness, has become an important choice in fields such as PVC modification, UV-cured coatings, green epoxy resins, and polymer blend compatibility.