Those little beads are called SAP, short for superabsorbent polymer. When they’re dry, they sit as tiny beads mixed into the core of the diaper. When they get wet, they swell into a gel that holds the liquid in so it doesn’t leak back out. It’s what lets a diaper hold so much without being bulky. Change Diapers® use the world’s first and only biodegradable Super Absorbent core.
Why the beads are there
A diaper’s core has to do two things: take in liquid quickly, and keep it there. Fluff pulp, the soft, fibery part, handles the first part. It draws liquid in and spreads it around. The catch is that pulp can’t hold very much, and it gives liquid back when it’s squished, like every time your baby sits. To hold a normal potty break with pulp alone, a diaper would need to be much bulkier.
The beads take care of the second part. Each one holds many times its own weight and turns into a gel that stays put under pressure. Pulp spreads the liquid, and the beads hold it. That’s why almost every disposable diaper uses both, and why the core is such a big part of a diaper’s weight.
What conventional beads are made from
In most disposable diapers, the beads are made of sodium polyacrylate. It comes from acrylic acid, which comes from petroleum, and that’s the case whether a diaper is budget or premium. If the front of a pack says “plant-based” or “bamboo,” that usually means the top sheet or outer cover, not what’s inside the core. If you can’t find the beads named on the materials list, it’s worth asking the brand what they use and what it’s made from.
Beads or gel on your baby? Here’s why.
When a diaper is full and the core can’t hold any more, the gel can slip through the top sheet, usually around the legs. It can also happen if the top sheet tears, which is more likely when a diaper gets stretched over a wiggly little one or is a size too small.
Either way, the gel is coming from the core, not the layer that touches your baby’s skin. It’s your cue for a fresh diaper, and if you’re seeing it a lot, a good reason to double-check the size and fit. A materials list can’t guard against this happening, but it can tell you exactly what that gel is made of, and that’s something every parent deserves to know.
Core facts to look for
When you’re reading a diaper’s materials list, a few details can tell you a lot about the core. Here’s what to look for.
| What to look for | What a complete answer looks like |
|---|---|
| The polymer, named | The name of the superabsorbent polymer, not just "SAP" or "absorbent gel" |
| What the polymer is made from | Its starting material: petroleum, a plant source, or something else the maker names |
| The pulp, named | The fiber in the fluff pulp and how it was bleached (TCF, ECF or unbleached) |
| Share of the diaper by weight | A percentage for the pulp and a percentage for the polymer, listed separately |
| What holds the core together | The core wrap material and the adhesive used |
| Any test the maker publishes | The method, the lab that ran it and the date, with a statement of what was tested: the polymer, the pulp or the finished diaper |
Just because something isn’t listed doesn’t mean it’s bad, or that it’s not in there. If all you see is “absorbent core,” go ahead and ask the brand for the full picture.
A peek inside a Change diaper
Tucked inside the cotton is the world’s first and only biodegradable Super Absorbent core. It isn’t made from fossil fuels, and it has been independently tested by a certified third-party lab to biodegrade.
The absorbent core makes up about half of a Change diaper by weight, and it’s a mix of fluff pulp and our Super Absorbent core. Just like in any disposable, it pulls wetness in and away from your baby’s skin. What makes ours different is that our Super Absorbent core is made from polysaccharide, and it has the biodegradation testing to back it up. We’ll be sharing a summary of that lab test on our site soon, including the method, the lab, and the date, so you can read it the same way this article walks you through.
Our Super Absorbent core is just one part of the diaper, so it doesn’t mean a used diaper as a whole will break down in your household trash or home compost bin. That’s why we list every component, along with its share of the diaper by weight, on our materials page, so you can see how the Super Absorbent core fits in with everything around it.
See Change’s sizes and purchase options, or read the materials and fit FAQ.