Sodium Lauroyl Isethionate CAS 7381-01-3

Introduction to Sodium Lauroyl Isethionate

Sodium Lauroyl Isethionate is a white to off-white powder or noodle, an anionic surfactant of the acyl isethionate family produced by esterifying lauric acid with isethionic acid and neutralising with sodium hydroxide. Commercial grades carry ≥85% active matter, the balance being mainly sodium isethionate with a small laurate soap fraction. The molecule pairs a C12 lauric chain with a sulfonated isethionate head, delivering effective cleansing together with a dense, creamy foam and good skin compatibility.

SLI lathers richly in both hard and soft water and leaves a soft, conditioned after-feel on skin. It is the core surfactant of syndet (soap-free) bars and gentle cleansers, and is used in facial cleansers, baby washes, body washes, shower gels, and shampoo bars. It works in neutral-pH formulas and combines with anionic, amphoteric, and non-ionic co-surfactants, emollients, and moisturisers, supporting sulfate-free and low-irritation formulation concepts.

Key Features of Sodium Lauroyl Isethionate

• Sulfate-free mild anionic. Low irritation potential suited to sensitive-skin and baby formulations; the CIR panel has assessed isethionate salts as safe in cosmetic practice.
• Rich, creamy lather. Builds a dense, cream-like foam in hard and soft water, giving syndet bars their characteristic velvety lather.
• Soft, conditioned after-feel. Deposits a light conditioned film that leaves skin soft and comfortable after rinsing, without a tight or stripped feel.
• Hard-water stability. Foam volume and cleansing performance hold in high-hardness water, and no insoluble soap scum forms on skin or surfaces.
• Broad formulation compatibility. Blends with anionic, amphoteric, and non-ionic surfactants, emollients, and electrolytes, and functions in neutral-pH, sulfate-free systems.
• Coconut-derived and biodegradable. Built from lauric acid and isethionic acid, supporting natural-origin and biodegradability claims.

Sodium Lauroyl Isethionate Chemical & Physical Properties

Applications of Sodium Lauroyl Isethionate

Syndet bars and soap-free cleansers: Used at 20–60% of the formula as the primary surfactant, combined with co-surfactants, emollients, and fillers. Delivers the dense creamy lather and soft after-feel that define premium syndet bars.

Facial cleansers and baby washes: Dosed at 5–15%. Low irritation potential and creamy foam suit sensitive-skin and baby formulations, leaving skin soft without a stripped feel.

Body washes and shower gels: Used at 3–10%, alone or with amphoteric co-surfactants. Builds rich, stable foam in hard and soft water and improves rinse-off feel.

Sulfate-free shampoos and shampoo bars: Used at 5–15%. Provides creamy lather and a conditioned after-feel in sulfate-free systems, supporting gentle daily-use hair care.

Gentle hand and industrial cleaners: Combined with co-surfactants in low-irritation hand cleaners and specialty cleansing products, delivering effective cleansing with a comfortable skin feel.

Storage & Safety Precautions for Sodium Lauroyl Isethionate

Storage conditions. Store in sealed, PE-lined kraft bags or fibre drums at 5–30 °C, in a dry warehouse. The powder is mildly hygroscopic and cakes above 70% RH; reseal opened bags immediately. Keep away from strong mineral acids and strong oxidisers.

Safety and PPE. GHS: Eye Irrit. 2 (H319). May cause eye irritation; avoid dust inhalation. Wear an N95 dust mask, safety glasses, and nitrile gloves during bag emptying. Spills: sweep up dry, then wash the floor with water—wet residue is slippery.

Transport classification. Non-DG. Not regulated under IMDG, IATA, or ADR. Ship as standard general cargo. Ensure container liners are intact to prevent moisture ingress during ocean freight.

Practitioner note: For incoming QC, verify active content by two-phase titration with a standardised cationic titrant, and check pH (5.5–7.5 at 10%) and loss on drying (≤2.0%). Powder grades generate dust during emptying—use local exhaust; noodle grades reduce dust and suit direct melt-in syndet bar processing.

Sodium Lauroyl Isethionate FAQ

Q: What is the difference between the powder and noodle grades of Sodium Lauroyl Isethionate (CAS 7381-01-3)?

A: Both carry the same ≥85% active content. Powder dissolves and disperses faster in liquid systems and suits dry-blend granulation; noodles generate less dust and melt directly into syndet bar mixes. Choose powder for liquid and granulated products, noodles for pressed syndet bars.

Q: Can SLI be used in sulfate-free and low-pH formulas?

A: Yes. SLI contains no sulfate group and performs at pH 5.5–7.5, the typical range of syndet bars and gentle cleansers. It blends with amphoteric and non-ionic co-surfactants to build complete sulfate-free systems.

Q: Why do my syndet bars turn soft or sticky after moulding?

A: Moisture uptake is the usual cause. Keep SLI and the finished bars in a dry environment below 60% RH, add hygroscopic-balancing fillers, and cool bars fully before wrapping. Verify the SLI loss on drying (≤2.0%) on arrival—wet raw material transfers moisture into the bar.