OP-4 (Octylphenol Polyoxyethylene (4) Ether) appears as a light yellow to yellow oily liquid (still liquid at <0°C). Its chemical structure is dominated by the lipophilic group (octylphenyl group), with only 4 EO units, resulting in limited hydrophilicity. It is soluble in oils and organic solvents but only dispersible in water (not water-soluble). This solubility characteristic determines that OP-4 is most suitable for use as an oil-phase additive, efficiently emulsifying a small amount of water to form a stable water-in-oil (W/O) system while imparting excellent wetting, penetration, and dispersion capabilities.
In practice, avoid adding OP-4 directly to the water phase in large quantities. The correct approach is to pre-dissolve or disperse it into the oily components, solvents, or liquid technical materials in the formulation. Mix thoroughly before emulsifying or diluting with the water phase. At room temperature, the viscosity of OP-4 is about 300 mPa·s (25°C), with acceptable fluidity. If the temperature is too low and viscosity increases, it can be heated to 30~40°C to aid flow, but avoid direct contact with open flames.
1. Pesticide Emulsifier
Used for formulating organophosphorus and pyrethroid emulsifiable concentrates (EC) or emulsion in water (EW). First, mix OP-4 according to the formulation amount (usually 5%~15% of the total formulation) with the pesticide technical material and organic solvent to form a transparent oil phase. Then slowly add water under stirring to allow self-emulsification into a stable emulsion. The low-foaming property of OP-4 is beneficial for field spraying operations.
2. Textile Dyeing and Printing Penetrant/Leveling Agent
Used as a penetration enhancer in fabric pretreatment (desizing, scouring, bleaching), with a recommended dosage of 0.5~3 g/L of working solution. Since it disperses in water, first stir it with a small amount of hot water (40~50°C) to form a coarse dispersion before adding to the treatment bath. Used as a leveling agent in high-temperature and high-pressure dyeing, with a dosage of 0.2~1 g/L, utilizing its low-foaming and dye uptake retarding properties to avoid color spots.
3. Industrial and Household Cleaners
Used for formulating metal parts degreasers and hard surface cleaners. As a key component in heavy-duty cleaning formulations, it is recommended to account for 5%~15% in the concentrated formula. When preparing, first mix OP-4 with other oil-soluble solvents and builders. Dilute with water to form a working solution before use. It has strong emulsifying and stripping ability for mineral oils and waxes, suitable for cleaning at temperatures from room temperature to 80°C.
4. Metalworking Fluids
Used as an emulsifying and lubricating component in cutting fluid and grinding fluid formulations. First dissolve other oil-based lubricants and rust inhibitors with OP-4 (recommended 5%~20% of the concentrate) to form a uniform oil phase. Then dilute with water to form a microemulsion or emulsion for use, significantly reducing processing friction and extending tool life.
5. Leather Degreasing Agent
Applied in the beamhouse stages such as liming and bating. Blend OP-4 with kerosene or other light mineral oils and nonionic surfactants, using 0.3%~1.0% of the pelt weight. Add directly to the drum for action, enabling deep penetration into leather fibers to effectively remove natural fats.
6. Petroleum Extraction and Processing
Used as an auxiliary emulsifier in heavy oil viscosity reduction or oil displacement systems. It is typically compounded with other surfactants, with a total dosage concentration of 0.05%~0.5% (depending on specific well conditions and crude oil properties) to adjust oil-water interfacial tension and improve heavy oil fluidity.
| Parameter Name | Specification Value | Impact on Usage |
|---|---|---|
| Ionic Type | Nonionic | Stable in acids, alkalis, and hard water; good compatibility with various auxiliaries |
| HLB Value | 8.8 | Strong lipophilicity, suitable for preparing W/O emulsions and as oil-based additives |
| Active Content | ≥99% | High purity, allowing reduced addition amount in formulations |
| Solubility | Soluble in oils and organic solvents, dispersible in water | Preferentially dissolve in oil phase; avoid direct large addition to water |
| 1% Aqueous Dispersion pH (25°C) | 5.0~7.0 | Neutral, mild to most substrates |
| Density (25°C) | 1.02~1.04 | Slightly denser than water, will settle and disperse in water |
| Cloud Point | None (insoluble in water) | Avoid heating in water for clarity; use solvent or oil for dilution |
| Foaming Property | Low foam | Particularly suitable for industrial high-pressure spraying, circulating cleaning, and dyeing processes |