A practical guide to sodium laureth sulfate, why the active matter figure decides your cost per wash, how salt builds viscosity, and how it is supplied, from a US-based distributor.
SLES (sodium laureth sulfate, CAS 68891-38-3) is the workhorse anionic surfactant of personal care and household cleaning, giving high foam and strong detergency with a milder skin feel than sodium lauryl sulfate. It is supplied as a concentrated aqueous paste, typically 58–62% active. Stratus Chemical supplies technical grade in drums and totes across the United States.
| Property | Value |
|---|---|
| Product name | Sodium lauryl ether sulphate |
| INCI name | Sodium Laureth Sulfate |
| Synonyms | SLES, sodium lauryl ether sulfate, SLES 70, laureth sulfate sodium salt |
| CAS number | 68891-38-3 |
| EC number | 500-234-8 |
| Chemical formula | R-OCH2CH2OCH2CH2OSO3Na (R = C12–14) |
| Molecular weight | 427 g/mol |
| Appearance | Clear, white viscous liquid |
| Grades supplied | Technical; commercial active concentrations |
| Packaging | Drums, totes |
| Documentation | COA & SDS provided on request |
The figures below are representative of technical grade SLES. They are indicative rather than guaranteed: specifications vary by source and by lot, and the certificate of analysis for your material governs.
| Parameter | Unit | Standard specification |
|---|---|---|
| Physical appearance | — | Clear, white viscous liquid |
| Odor | — | Odorless |
| Active matter | % | 58 – 62 |
| Unsulphated alcohol | % | 1.5 max |
| Sodium sulphate (as Na2SO4) | % | 0.5 max |
| Sodium chloride (as NaCl) | % | 2.5 max |
| pH (3% aqueous solution) | — | 6.5 – 9.5 |
| Klett colour | — | 11 max |
SLES is sold as a concentrate, and the active matter percentage is the only number that makes two quotes comparable.
The rest of the drum is water. A 60% active product and a 70% active product are the same surfactant at different dilutions, so a lower price per ton on the weaker material can easily be a higher price per unit of surfactant delivered. Divide the quoted price by the active matter figure before comparing anything.
Freight follows the same logic. Shipping a 60% paste means paying to move 40% water, which matters over distance and is the reason concentrated grades exist despite being harder to handle.
The impurity lines on an SLES certificate are short, and each one corresponds to a specific failure in the finished product.
Unsulphated alcohol is fatty alcohol that never reacted. It contributes nothing to cleaning, can cloud a clear formulation, and carries an odour that becomes noticeable as it oxidises over shelf life.
Sodium chloride is the parameter formulators watch most closely, because salt is what builds viscosity in an SLES system. The relationship is not linear: viscosity climbs with added salt, peaks, and then falls again. If the incoming material varies in chloride from lot to lot, a fixed salt addition in the batch sheet will land at different points on that curve, and the product will thicken inconsistently. This is the most common cause of viscosity variation in a cleansing base.
Sodium sulphate is a by-product that adds no performance and, at higher levels, can cause haze or precipitation in cold storage. Klett colour is a straightforward appearance control for clear products.
The primary use. SLES delivers the dense, fast foam that consumers read as cleaning, at low cost and with good hard-water tolerance. It is almost always paired with an amphoteric co-surfactant such as cocamidopropyl betaine, which raises mildness and helps build viscosity.
Used for grease cutting and foam in hand dishwashing and in liquid laundry detergents, often alongside DDBSA / LABSA for cost-effective detergency.
SLES tolerates the alkaline conditions of many industrial cleaning formulations better than some alternatives, and is used as the primary foaming surfactant in a wide range of cleaners.
SLES appears in car care products, textile processing, emulsion polymerisation, and oilfield formulations.
| Surfactant | Where it wins | Trade-off |
|---|---|---|
| SLES | High foam, strong detergency, good hard-water tolerance, low cost | Anionic and can be irritating at high levels; needs a co-surfactant for mildness |
| SLS (sodium lauryl sulfate) | Higher foam and detergency still, cheaper per unit active | Noticeably harsher on skin; poorer hard-water tolerance |
| Cocamidopropyl betaine | Mild, boosts and stabilises foam, builds viscosity with SLES | Weak as a primary surfactant and more expensive; used as a partner |
| Alkyl polyglucosides | Very mild and plant-derived, good for sulfate-free claims | Lower foam and higher cost; usually needs reformulation of the whole base |
How to choose: SLES is the default primary surfactant for a cost-driven cleansing base and is hard to beat on foam per dollar. It is not used alone in modern formulations — pairing it with an amphoteric raises mildness and gives the salt-response needed to build viscosity. Where the product carries a sulfate-free claim, the whole base has to be rebuilt around glucosides or other alternatives, and that is a formulation project rather than a substitution.
Store SLES in closed original packaging in a cool, ventilated place, out of direct sunlight and away from freezing. It is a viscous paste that becomes very difficult to pump when cold, so heated storage or a warm dispensing area is worth planning for in winter.
Prolonged storage at elevated temperature can cause the material to darken and, over long periods, to hydrolyse, which reduces active content and can raise the free alcohol level. Do not hold it hot as a matter of routine.
SLES concentrate is irritating to skin and eyes; dilute solutions much less so. Use the eye protection and gloves specified in the Safety Data Sheet, and note that spills are extremely slippery and foam heavily when hosed down.
SLES is used as the primary anionic surfactant in shampoos, body washes, hand dishwashing liquids, liquid laundry detergents, and hard-surface cleaners, where it provides high foam and strong detergency at low cost. It is also used in car care products, textile processing, and emulsion polymerisation. Stratus Chemical supplies technical grade SLES in drums and totes across the United States.
The CAS number for SLES is 68891-38-3, corresponding to the C12-14 sodium laureth sulfate. Its EC number is 500-234-8 and its INCI name is Sodium Laureth Sulfate. Its molecular weight is approximately 427 g/mol and its formula is R-OCH2CH2OCH2CH2OSO3Na where R is C12-14.
The ether linkage. SLES is ethoxylated, meaning ethylene oxide units sit between the fatty alcohol and the sulfate group, while SLS has none. Those units make the molecule bulkier and less able to disrupt skin proteins, so SLES is noticeably milder than SLS while still foaming well. SLES also tolerates hard water better. SLS foams and cleans slightly more aggressively and costs less per unit active, which is why it persists in applications where skin contact is brief.
Because SLES is sold as a concentrate and the balance is water. A product at 60 percent active and one at 70 percent are the same surfactant at different dilutions, so a lower price per ton can still be a higher price per unit of surfactant delivered. Divide the quoted price by the active matter figure before comparing, and account for the freight cost of the water you are shipping.
Salt is what builds viscosity in an SLES system, but the relationship is not linear. Viscosity rises as sodium chloride is added, reaches a peak, and then falls again with further addition. This matters because incoming SLES already contains chloride, typically specified at 2.5 percent maximum. If that figure varies between lots, a fixed salt addition in the batch sheet lands at a different point on the curve each time and the product thickens inconsistently. It is the most common cause of viscosity variation in a cleansing base.
Store SLES in closed original packaging in a cool, ventilated place, out of direct sunlight and protected from freezing. It is a viscous paste that becomes very hard to pump when cold, so plan for heated storage or a warm dispensing area in winter. Avoid prolonged storage at elevated temperature, which darkens the product and over time hydrolyses it, reducing active content.
Stratus Chemical supplies SLES in drums and totes, in technical grade at commercial active concentrations, with a certificate of analysis and Safety Data Sheet provided on request. Tell us the active matter you are working to and the volume, and we will confirm pricing and availability within one business day.
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