Calcination drives off the water of crystallisation and sinters the platelets, which raises whiteness, hardness and oil absorption. Hydrous kaolin stays softer and is used where you want a clay that disperses easily and does not dull the film.
In a pressed powder, calcined kaolin contributes press strength and mattness; hydrous kaolin contributes slip and a smoother feel. That is why calcined kaolin shows up in oil-control and long-wear formulas rather than in products where glide is the priority.
Our range here is calcined only — the two 5000 and GL03 series.
2 µm if you want maximum oil absorption and a matte finish; 3 µm if you want easier dispersion and a less dry feel.
The finer grade has more surface per gram, so it takes up more sebum and gives a flatter, more powdery finish — the effect people describe as 'matte' in a compact. It also raises viscosity in a slurry and is harder to wet out. The 3 µm grade trades a little of that mattness for noticeably easier processing.
A common compromise is to use the finer grade in the powder phase and the coarser one where you need the batch to move.
Because the calcination step creates a harder, more angular particle that interlocks under pressure instead of sliding past its neighbours.
Soft platy fillers such as talc and mica slide, which is what gives slip but also what lets a compact crumble. Calcined kaolin particles key into each other and hold the structure. In a talc-reduced compact, that is often the reason the formula still presses at all.
The practical limit is feel: above roughly 15% the compact starts to feel dry and chalky on application.
5–15% is the usual band. Below 5% you mostly get a mattifying effect with little structural contribution; above 15% the dryness becomes the dominant sensation.
At 8–12% you get both the oil absorption and a measurable improvement in press hardness without the formula reading as powdery. That is the band most oil-control pressed powders are built in.
In a loose powder the ceiling is higher because there is no press strength requirement — 20% is workable if the feel still reads smooth.
Up to a point, then it plateaus and starts to cost you comfort.
Oil absorption rises with loading, but once the powder is saturated the excess oil simply sits on top of the film, and the dry feel of a heavily loaded formula makes the wear experience worse even though the measured shine is lower. The useful range is where the powder is still able to take up oil — typically up to 12–15%.
If oil control is still short at that level, the answer is usually a different mechanism (a porous silica, a film former) rather than more kaolin.
Yes, and it is one of the easier substitutions — 20–40% of the talc is a reasonable starting point.
Both are platy aluminosilicates, so the texture translates without a big reformulation. What changes is that calcined kaolin absorbs more oil and presses harder, so you gain wear and oil control and lose some slip. Adding 2–3% of a spherical or a softer filler usually restores the glide.
Going beyond 40% starts to feel dry, and the whiteness of a calcined grade can shift the shade in a tinted product.
The specification holds whiteness within a defined band, but calcined kaolin is a natural-mineral product, so there is lot-to-lot variation inside that band.
For a tinted product, that matters more than the nominal number: a 1–2 point shift in whiteness in a low-pigment formula is visible. The practical answer is to qualify two or three lots against your own colorimetric standard before locking the formula, and to ask for the COA of the specific lot on each reorder.
If the shade is critical, a synthetic filler gives you a tighter window at a higher cost.
It is produced and tested against a tighter heavy-metal profile, which is what most market-specific cosmetic questionnaires actually ask about.
The base grade meets the general cosmetic specification. The GL series is held to the stricter limits that some markets and some customer SOPs apply, and it comes with the documentation to demonstrate it. That is the entire difference — the particle size and the performance are the same as the corresponding standard grade.
If your customer sends a heavy-metal questionnaire, ask for GL before you promise anything.
It wets out slowly but disperses cleanly once wetted — the difficulty is the initial wetting, not the breakdown.
In a dry powder blend it is simply blended. In a slurry or a cream it needs shear: a high-speed disperser at 1500–2500 rpm for 15–20 minutes is usually enough, and a bead mill gives a tighter particle size distribution if the finish matters. Adding it to the oil phase before the water phase reduces the lumping that happens when a fine calcined clay hits water directly.
If you see specks in the finished product, check for undispersed lumps rather than oversized particles — calcined clay forms them readily.
We reply within one business day with shipping arrangements and technical documents. Samples are free of charge; freight is collect or credited against your next order.
