Buying SLMI (Sodium Lauroyl Methyl Isethionate): What Matters
Sodium lauroyl methyl isethionate (SLMI, CAS 928663-45-0) is a premium mild surfactant, and its price reflects that. Buying it well means confirming the identity and grade, checking the parameters that drive performance and appearance (active matter, colour, free fatty acid, odour), and matching the form to your process.
For the chemistry and applications behind these points, see our main article on sodium lauroyl methyl isethionate (SLMI, CAS 928663-45-0).
Step 1: Confirm the Identity and Grade
| Item | What to confirm |
|---|---|
| Substance | Sodium lauroyl methyl isethionate (SLMI) |
| CAS number | 928663-45-0 |
| Chain | Lauroyl (C12), distinguishing it from cocoyl SCI |
| Active matter | Typically 79% min |
Do not confuse SLMI with SCI (sodium cocoyl isethionate): both are acyl isethionates, but SCI uses a mixed cocoyl chain.
Step 2: Read the Specification
| Parameter | Why it matters | Typical value |
|---|---|---|
| Active matter | Dosing basis and cost per active unit | 79.0% min |
| Free fatty acid | Affects foam, feel and base odour | 7.0% max |
| pH (10% solution, 35 deg C) | Skin compatibility | 5.5 – 7.0 |
| Colour (5% in IPA/water) | Whiteness of bars and creams | 25 max |
| Water | Stability and dosing of a solid | 1.0% max |
Active matter, colour and free fatty acid are the three parameters that most affect the finished product; odour matters for fragrance-free and premium positioning.
Step 3: Match the Form to Your Process
- Chips / flakes. The standard form; dissolved with gentle heating in hot-process manufacturing.
- Powder / milled. For easier and faster dissolution.
- Pre-blended liquid. For cold-process formulation.
Step 4: Confirm Quality and Documentation
- Per-batch COA with measured values, not just limits.
- Irritation data (for example HET-CAM or patch testing) if you make mildness claims.
- SDS and, where relevant, cosmetic/regulatory statements.
- Batch history if your formula was validated against a specific colour or active level.
Supplier Checklist
- Identity. CAS 928663-45-0 and the lauroyl (C12) chain confirmed.
- Active matter. 79% min, consistent.
- Colour and odour. Low and consistent.
- Free fatty acid. Within limit.
- Form and packaging suited to your process (chips, powder or blend).
- Documentation. COA, SDS and irritation data for claims.
Common Buying Mistakes
- Confusing SLMI with SCI. Different chain and performance; confirm the CAS.
- Buying on active matter alone. Colour and odour decide whether a premium product performs visually and olfactorily.
- Ignoring free fatty acid. High residual fat can dull foam and add base odour.
- Skipping claims data. Mildness claims need supporting test data, which should come with the grade.
- Poor storage. SLMI is hygroscopic; poor storage affects dosing and shelf life.
How PolyBlueChem Can Help
PolyBlueChem can supply sodium lauroyl methyl isethionate (CAS 928663-45-0), with the documentation appropriate to your application. To request current specifications, a COA or a quotation, contact the PolyBlueChem team.
Frequently Asked Questions
What should I look for when buying SLMI?
Confirm the CAS (928663-45-0) and the lauroyl chain, check active matter, colour, free fatty acid and odour, choose the right form, and secure the COA, SDS and any irritation data.
How much active matter does SLMI contain?
Typically 79% min; dose the surfactant on an active-matter basis.
Is SLMI the same as sodium cocoyl isethionate?
No. SCI uses a mixed cocoyl (C12–C18) chain; SLMI uses a pure lauroyl (C12) chain.
What documents should come with a shipment?
At minimum an SDS and a per-batch COA; irritation test data where mildness claims are made.
How should SLMI be stored?
Sealed, cool and dry, protected from moisture and heat.