Quick answer: sodium polyacrylate and polyacrylamide can both thicken water, and they are not the same purchase. Sodium Polyacrylate is the sodium salt of polyacrylic acid, CAS 9003-04-7, repeating unit (C3H3NaO2)n. Polyacrylamide is built from acrylamide. The monomer decides which COA you are allowed to accept, and which residual limit applies.
Disperse-then-hydrate, salt, and the diaper-grade fork are in Sodium Polyacrylate in Skincare Is a Water-Phase Thickener.
Different monomers, different COAs
Sodium polyacrylate on this page is acrylic acid neutralized as the sodium salt. It is sold here as a white to off-white powder that hydrates in water into a viscous solution or gel. Polyacrylamide is polymerized acrylamide. The names share “poly,” and both can look like white powders. They are not interchangeable INCI lines.
A lot labeled only “acrylate polymer,” “water thickener,” or “acrylic polymer” has not chosen between them. This site has no polyacrylamide product page. If the brief names polyacrylamide, that polymer needs its own INCI, its own supplier, and its own residual-monomer specification. It does not ship against a sodium polyacrylate order, and a sodium polyacrylate COA does not satisfy a polyacrylamide PO.
The 5 ppm figure stays with polyacrylamide
CIR’s amended conclusion, restated in the 2022 re-review memo, is that polyacrylamide is safe as used in cosmetics when the acrylamide monomer in the formulation is not greater than 5 ppm. The memo records the earlier wording as well: a 1991 review had spoken in terms of less than 0.01% acrylamide monomer in the polymer, and the 2005 amendment moved the practical cap to residual acrylamide in the formulation at or below 5 ppm. A later journal reaffirmation kept that conclusion. The 2022 memo also notes use-concentration surveys for polyacrylamide itself (maximum reported use on the order of a few percent). Those numerals describe polyacrylamide. They are not a test limit and not a use percent you copy onto sodium polyacrylate.
Ask the polyacrylamide COA for residual acrylamide if that is the polymer you bought. Ask the sodium polyacrylate COA for identity, CAS 9003-04-7, appearance, and the viscosity or hydration note you specified. Mixing the two questions is how a quote gets priced against the wrong drum.
Acrylamide/acrylate copolymers are a further family in CIR’s files, also discussed with residual-acrylamide controls. A copolymer INCI is not silent equivalence to either homopolymer. If the brief names a copolymer, match that INCI before you sample.
Potassium salt and carbomer are further forks
Potassium polyacrylate is the potassium salt of the same acid family, not this sodium salt. Swapping the cation changes the INCI. A search for sodium polyacrylate versus potassium polyacrylate is a salt choice, not a spelling variant.
Carbomer is another acrylic thickener. A search that pairs “sodium polyacrylate and carbomer” is an “and,” not proof that the powders match or that one can fill the other’s PO. This site has no page for potassium polyacrylate or for carbomer. Do not invent a URL. Write the INCI you actually need, and send the sodium salt inquiry only when the line is Sodium Polyacrylate.
How to choose on the RFQ
| Brief says | What to order |
|---|---|
| Sodium polyacrylate / CAS 9003-04-7 / cosmetic water-phase thickener | Sodium Polyacrylate (this page) |
| Polyacrylamide / residual acrylamide / 5 ppm | Polyacrylamide from a supplier who will report that monomer; not this sodium salt |
| Acrylamide/acrylate copolymer named | That copolymer INCI, not either homopolymer by default |
| Potassium polyacrylate | The potassium salt, not CAS 9003-04-7 |
| Carbomer, or “acrylate thickener” with no INCI | Ask for the INCI before sampling |
| Diaper crystals / superabsorbent spec | Confirm grade; do not assume this cosmetic powder |
What the documents must show before price means anything
Keep three checks on the same email thread: the INCI string Sodium Polyacrylate, CAS 9003-04-7, and a grade statement that this lot is the cosmetic thickener rather than a diaper superabsorbent or a polyacrylamide. If any of those three fails, the quote is pricing the wrong drum even when the salesperson says “same acrylic family.” Formula nicknames and “SAP” shorthand are not substitutes for the CAS line.
What to put in the quote or sample email
- Exact INCI: Sodium Polyacrylate, not “acrylic polymer”
- CAS 9003-04-7 on the COA
- Confirmation the lot is not polyacrylamide and not a potassium salt
- Cosmetic grade versus superabsorbent grade, in writing
- Viscosity or hydration expectation, plus whether your water phase contains salt
- Sample pack size, plus COA, SDS, and TDS
Documents for the sodium salt are on the product page. Send the inquiry only after the monomer and the CAS are locked. A clear sodium-polyacrylate line usually returns documents and a quote. A line that says only “polyacrylamide or sodium polyacrylate” usually returns a second round of clarification.
