OP-21 octylphenol polyoxyethylene ether (CAS number: 9036-19-5), also known as emulsifier OP-21, octylphenol polyoxyethylene (21) ether, polyoxyethylene (21) octyl phenyl ether, is a classic nonionic surfactant. Its appearance is a white to light yellow waxy paste, with extremely high active matter content and concentrated effective components, achieving excellent performance with a small dosage, thereby reducing overall formulation costs.
As a nonionic surfactant, OP-21 does not ionize in solution and exhibits excellent compatibility with anionic, cationic, and amphoteric surfactants, allowing flexible compounding. Its core properties include: outstanding emulsifying ability, forming fine and stable emulsions with various oil phases and organic solvents; excellent wetting and penetrating properties, significantly reducing liquid surface tension for rapid and uniform wetting and spreading; efficient dispersion and scouring ability, with good dispersion and suspension effects on solid particles; and strong tolerance, maintaining stable surface activity in acidic, alkaline, and hard water systems.
It is worth noting that the octylphenol group of OP-21 has endocrine-disrupting properties in the environment, making it a surfactant species that requires attention to its environmental impact. During use, safety operating procedures must be strictly followed, waste must be properly disposed of, and it must not be discharged into natural water bodies.
Used as an efficient penetrant, scouring agent, and leveling agent, effectively improving fabric pretreatment effects and dyeing uniformity, suitable for processing cotton, synthetic fibers, and their blends.
Applied in degreasing and fatliquoring processes, helping to remove natural grease from leather and promoting uniform penetration of fatliquoring agents, improving leather softness and finished hand feel.
Used as a wetting and dispersing agent in pulping and deinking of waste paper, accelerating ink detachment and dispersion, improving deinking efficiency, and enhancing the wetting properties of pulp fibers.
Core active component in formulating high-performance household and industrial cleaning products and hard surface cleaners, providing excellent detergency, emulsification, and wetting capabilities, with good removal effects on various oils and soils.
Serves as an efficient emulsifier in emulsifiable concentrate and emulsion concentrate formulations, ensuring rapid dispersion of active ingredients in water and formation of stable emulsions, improving spray adhesion and utilization rate.
Used as a wetting and dispersing agent for pigments and fillers, shortening grinding time, preventing pigment flocculation, and improving storage stability and color development of coatings and inks.
Acts as an emulsion stabilizer in polymerization processes, ensuring stable dispersion of monomer droplets and polymer latex particles, controlling particle size, and optimizing final emulsion performance.
Provides synergistic effects of lubrication, cleaning, and rust prevention, enhancing the cooling, lubrication, and cleaning properties of working fluids, while effectively removing mineral oils and animal/vegetable oils in metal degreasing formulations.
| Parameter Item | Parameter Value |
|---|---|
| Product Name | OP-21 octylphenol polyoxyethylene ether |
| CAS Number | 9036-19-5 |
| Ionic Type | Nonionic surfactant |
| Appearance | White to light yellow waxy paste |
| pH Value (1% aqueous solution, 25°C) | 6.0–8.0 |
| Flash Point (closed cup) | >150°C |
| HLB Value | Not available |
| Cloud Point | Not available |
| Hydroxyl Value | Not available |