Question

How to use OP-21 Octylphenol Ethoxylate? What is the recommended dosage?

Answer
2026-06-06 官方文档 OP-21辛基酚聚氧乙烯醚

OP-21 is a high HLB value non-ionic emulsifier in paste to solid form. It is recommended to pre-dissolve it in warm water or heat to melt before adding to the formulation system. The dosage typically ranges from 0.5% to 10% depending on the application scenario.

Detailed Description

OP-21 Octylphenol Ethoxylate (CAS: 9036-19-5) is a white to light yellow paste or solid at room temperature (melting point approx. 45~50°C), with an HLB value as high as 16. It is readily soluble in water and belongs to the strongly hydrophilic non-ionic surfactant type. Due to its paste/solid form, direct addition may result in slow dissolution and uneven dispersion; pre-treatment before use is recommended: heat OP-21 to above 50°C to melt it into a flowable liquid, or pre-disperse it with 50~60°C warm water to form a slurry or solution before adding to the main formulation system. During the mixing process, avoid prolonged high-speed shearing to prevent excessive foaming (this product is medium to low foaming), and after thorough mixing, check the stability of the system.

The cloud point of OP-21 is ≥100°C, indicating that it maintains excellent surface activity and solubility in high-temperature aqueous systems under normal pressure, making it suitable for high-temperature process conditions. As a non-ionic surfactant, it has good chemical stability in acids, alkalis, and hard water, and can be used in combination with anionic, cationic, and amphoteric surfactants without compatibility issues.

Technical Parameters

ParameterValue
HLB Value16
Active Content≥99%
AppearanceWhite to light yellow paste or solid
Melting PointApprox. 45~50°C
pH Value (1% aqueous solution)5.0~7.0
Cloud Point≥100°C
Critical Micelle Concentration (CMC)2.5×10⁻⁴ mol/L
Surface TensionApprox. 32 mN/m
Foaming CharacteristicsMedium to low foam
Penetration Power (1% aqueous solution)>180 s
Water SolubilityReadily soluble in water
Ionic TypeNon-ionic

Application Suggestions and Recommended Dosage

The following dosages are typical industrial references for various application fields (based on total formulation weight). The specific dosage should be optimized through experiments according to the actual system and process conditions:

Application FieldRecommended Dosage (wt%)RoleUsage Points
Textile Dyeing & Finishing (Scouring/Penetration)0.5~3.0Penetrating agent, Scouring agent, Leveling agentResistant to alkali and high temperature, suitable for desizing, scouring, bleaching and other pretreatment processes
Leather Processing (Degreasing/Fatting)0.5~2.0Degreasing aid, Fatting penetrating agentUsed in warm water systems to promote emulsification and removal of internal fat in leather
Paper/Waste Paper Deinking0.1~0.5Wetting dispersantStable under alkaline deinking conditions, accelerates ink detachment
Industrial & Household Detergents2.0~8.0Main active or co-activeGood emulsifying and removal effect on heavy grease, can be compounded with non-ionic/anionic surfactants
Pesticide EC/EW Formulations3.0~10.0EmulsifierHLB 16 suitable for O/W emulsions, often used in combination with low HLB emulsifiers
Paint/Ink Pigment Pastes0.5~3.0 (based on pigment)Pigment wetting dispersantHelps shorten grinding time, improves paste flowability
Emulsion Polymerization1.0~4.0 (based on monomer)Polymerization emulsifierEnsures stable dispersion of monomer droplets and latex particles
Metalworking Fluids/Degreasers1.0~5.0Emulsifying cleaning componentEnhances emulsification and cleaning ability for mineral oils and animal/vegetable oils

Note: The Guoli Chemical product database does not currently have official standard dosage data for each application scenario. The recommended dosages above are based on product characteristics such as HLB value and CMC value, as well as industry common practices. The optimal dosage in a specific formulation should be determined through experiments based on oil phase type, process conditions, and performance requirements.

Precautions

  • Pre-dissolution operation: The product is a paste/solid at room temperature (melting point 45~50°C). It is recommended to pre-dissolve in 50~60°C warm water or heat to melt before addition to ensure rapid dissolution and uniform dispersion.
  • Protective requirements: Wear protective gloves, goggles, and protective clothing during operation to avoid skin and eye contact. This product may cause skin irritation and serious eye irritation (GHS category 2/2A).
  • Environmental control: Contains octylphenol group, toxic to aquatic organisms and has endocrine-disrupting properties. Wastewater must be treated according to relevant regulations and must not be discharged directly into water bodies.
  • Storage conditions: Store in a cool, dry place, and keep under lock (P405). Keep away from children and unauthorized personnel. The product is hygroscopic; seal tightly after opening.
  • Formulation compatibility: OP-21 is a non-ionic surfactant with good compatibility with anionic, cationic, and amphoteric surfactants. Synergistic effects can be achieved in formulations.
  • Reproductive toxicity warning: Long-term or repeated exposure may cause damage to fertility or the unborn child (H361). Personnel should avoid prolonged high-dose exposure.