SODIUM LAYURL ETHER SULFATE (SLES)

 

What is SLES?

SLES stands for Sodium Laureth Sulfate. It is a common ingredient found in many personal care and cleaning products, such as shampoos, body washes, toothpaste, and household cleaners. SLES is a surfactant, which means it helps to create foam and lather, making it effective in removing dirt, oil, and grease from surfaces.

physical and chemical specifications

Physical Specifications:

Appearance: Clear to a slightly yellow viscous liquid.
Odor: Characteristic odor, typically mild.
Specific Gravity: Typically ranges from 1.015 to 1.035 g/mL.
Solubility: Soluble in water, miscible in ethanol and glycerol.
Viscosity: Generally has a viscosity ranging from 400 to 1500 mPa·s (at 25°C).

Chemical Specifications:

Chemical Name: Sodium Laureth Sulfate.
CAS Number: 68585-34-2.
Molecular Formula: C12H25NaO4S.
Active Ingredient: Typically contains 28-30% active ingredient, Sodium Laureth Sulfate.
pH: Typically ranges from 6.0 to 7.5 in a 1% aqueous solution.
Free Sulfuric Acid Content: Usually specified to be less than 1.5%.
Sodium Sulfate Content: Typically specified to be less than 1.5%.
Free Ethylene Oxide and 1,4-Dioxane Content: These impurities are usually controlled to low levels due to the manufacturing process.

Grades

• Standard Grade: This is the most commonly used grade of SLES and typically meets industry standards for purity and quality. It is suitable for use in a wide range of personal care and household cleaning products.
• High Purity Grade: This grade of SLES is characterized by higher purity levels, often achieved through additional refining processes. High-purity SLES may be preferred for certain applications where strict quality requirements are necessary, such as in pharmaceutical or industrial formulations.
• Low Irritation Grade: Some manufacturers offer SLES formulations specifically designed to minimize skin and eye irritation. These formulations may contain lower concentrations of impurities or additives aimed at reducing potential sensitivities.
• Ethoxylate Content Variations: SLES may also be available in different grades based on variations in the ethoxylate content. For example, SLES with higher degrees of ethoxylation may exhibit different foam characteristics or solubility properties compared to standard formulations.
• Custom Grades: Manufacturers may offer custom formulations of SLES tailored to specific customer requirements, such as variations in active ingredient concentration, viscosity, or other performance attributes.

SLES Application and usage

Personal Care Products:

• Shampoos
• Conditioners
• Body Washes
• Shower Gels
• Facial Cleansers
• Hand Soaps
• Bubble Baths
• Toothpaste
• Shaving Creams and Gels
• Moisturizers (in some formulations)
• Sunscreen Lotions (in some formulations)

Household Cleaning Products:

• Dishwashing Detergents
• Laundry Detergents (both liquid and powder)
• All-Purpose Cleaners
• Floor Cleaners
• Glass Cleaners
• Bathroom Cleaners
• Carpet Cleaners
• Oven Cleaners
• Metal Cleaners
• Furniture Polish

Industrial Applications:

• Metal Cleaning
• Textile Processing
• Leather Processing
• Paper Processing
• Paint and Coating Formulations
• Adhesive and Sealant Formulations
• Agricultural Formulations (e.g., pesticide emulsifiers)

Automotive Products:

• Car Wash Shampoos
• Engine Degreasers
• Wheel Cleaners
• Interior Cleaners

Medical and Pharmaceutical Applications:

• Some topical medications and ointments
• Some oral care products used in dental procedures

Cosmetic Products:

Makeup Removers
Makeup Brush Cleaners
Nail Polish Removers

Pet Care Products:

• Pet Shampoos
• Pet Conditioners
• Pet Wipes

Other Miscellaneous Applications:

• Firefighting Foams (used as a foaming agent)
• Water Treatment (used in some formulations)
• Agricultural Applications (e.g., in pesticide formulations)

Sodium Laureth Sulfate (SLES) is a highly versatile ingredient with excellent foaming and cleansing properties, making it suitable for a wide range of applications across various industries. However, it’s important to note that while SLES is widely used, some individuals may have sensitivities to it, and thus, manufacturers may offer alternative formulations in response to consumer preferences.

PRODUCTION PROCESS of SLES

• Ethoxylation: The process begins with the ethoxylation of either ethylene oxide (EO) or ethylene oxide and fatty alcohols derived from petroleum or palm oil. Ethoxylation involves reacting ethylene oxide with fatty alcohols under controlled conditions, typically with the presence of a catalyst such as potassium hydroxide or sodium hydroxide. This reaction produces a range of ethoxylated compounds, including ethoxylated fatty alcohols.
• Sulfation: The ethoxylated fatty alcohols are then sulfated to produce Sodium Laureth Sulfate (SLES). Sulfation is carried out by reacting the ethoxylated fatty alcohols with sulfur trioxide (SO3) or chlorosulfonic acid (HSO3Cl) in the presence of a suitable neutralizing agent, such as sodium hydroxide (NaOH) or sodium carbonate (Na2CO3). This reaction forms the sodium salt of the sulfate ester, which is SLES.
• Neutralization: After sulfation, the resulting SLES is typically in the form of a highly acidic solution. To make it suitable for use in consumer products, the SLES solution is neutralized to adjust its pH to the desired level. This is typically achieved by adding an alkaline substance such as sodium hydroxide (NaOH) or ammonium hydroxide (NH4OH) to the solution until the desired pH is reached.
• Concentration: The neutralized SLES solution may undergo concentration to increase its active ingredient content. This is typically achieved by removing water through processes such as evaporation or distillation until the desired concentration is reached.
• Quality Control: Throughout the production process, quality control measures are implemented to ensure that the SLES produced meets the required specifications and standards. This may involve testing the product for parameters such as active ingredient content, pH, viscosity, color, odor, and impurity levels.

Safety

• Personal Protective Equipment (PPE): Wear appropriate PPE such as gloves and safety goggles when handling concentrated SLES to prevent skin and eye contact.
• Avoid Inhalation: Avoid breathing in vapor or mist generated from SLES solutions. Ensure adequate ventilation in areas where SLES is handled.
• Dilution: When diluting concentrated SLES solutions, always add SLES to water, not water to SLES, to minimize splashing and potential skin or eye contact.
• Storage: Store SLES containers tightly closed in a cool, dry, well-ventilated area away from incompatible materials. Follow manufacturer recommendations for storage conditions.
• First Aid Measures: In case of skin contact, wash the affected area with water and remove contaminated clothing. In case of eye contact, rinse your eyes thoroughly with water for several minutes, holding your eyelids open. Seek medical attention if irritation persists.
• Spill Cleanup: In case of spills, contain the spill and absorb it with appropriate inert material. Dispose of waste according to local regulations.
• Handling Precautions: Avoid contact with incompatible materials such as strong acids, bases, and oxidizing agents. Follow good hygiene practices and wash hands thoroughly after handling SLES.
• Emergency Procedures: Know the location of emergency showers, eyewash stations, and spill control equipment. In case of emergencies, follow established procedures and seek medical attention if necessary.
• Labeling and Information: Ensure containers of SLES are properly labeled with hazard information and handling instructions. Educate personnel on the safe handling and storage of SLES.
• Regulatory Compliance: Familiarize yourself with relevant safety regulations and guidelines for handling chemicals, including SLES, in your jurisdiction.

 

In summary, Sodium Laureth Sulfate (SLES) is a versatile and widely used surfactant valued for its excellent cleansing and foaming properties in personal care, cosmetic, and household cleaning products. Its effectiveness, compatibility, and cost-effectiveness make it a staple ingredient in many formulations across various industries.

TECHNICAL DATA SHEET OF SODIUM LAURYL ETHER SULFATE (SLES)

Analysis Methods	Specification Limits
Molecular Weight (g/mol)	384
Sodium Lauryl Ether Sulfate %w/w	70±2
Non-Detergent Organic Matter %w/w	Max 2.5
Sodium Sulfate %w/w	Max 1.5
Color (10% in water) Hazen	Max 30
Dioxane (ppm)	Max 50
pH(5% in water)	7-9
Oxidizing Agents ppm (as H2O2)	0