Spherical Porous Silica FAQ

By how much oil you need taken out of the formula, and how dry you can afford the finish to feel.

Low oil absorption (Kingsica S060 at 60, TR070SI at 70) suits formulas that already contain enough oil-absorbing filler and only need texture. Mid range (2028 / 3028 / 5028 / 1228 at 90–100) is the general-purpose zone for pressed and loose powder. High values (S151 at 150, S201 / S202 at 200, S300 / S302 at 300) are for oil control and for matte, and they take up a lot of binder along with the oil.

The mistake to avoid is picking the highest number available. High oil absorption also means higher binder demand and a tighter, drier feel, so the right value is the lowest one that meets your oil-control target.

Particle size is nearly the same; oil absorption is not. S201 is 7 µm at 200, S300 is 7 µm at 300. S202 is 5 µm at 200, S302 is 5 µm at 300.

So these pairs let you change oil absorption without changing particle size, which matters when you are tuning oil control and do not want the skin feel or the scattering behaviour to move at the same time. Going from 200 to 300 typically means more oil taken up, a drier finish, and more binder needed to keep the compact together.

If you are troubleshooting one variable at a time, stay within a pair. If you change size and oil absorption together, you will not be able to tell which one caused the result.

The fine, mid-absorption spherical grades — 2028 at 2 µm and 3028 at 3 µm — are the usual starting point, typically at 2–6%.

Soft-focus comes from the spherical shape and the pore-size distribution rather than from oil absorption, so a high-absorption grade is not automatically better at it. What the fine spherical grades do well is fill and blur without a heavy feel, because the spheres roll rather than stack.

Above roughly 6% you usually stop gaining blur and start losing coverage or slip, because the silica is displacing pigment and platy filler. If you need more blur than that, combine it with a platy soft-focus filler instead of increasing the silica.

The PC series — PC20 (20 µm), PC100 (100 µm), PC150 (150 µm) and PC200 (200 µm), at oil absorption 100–130.

For scrubs the particle size sets the sensation: 100–200 µm reads as a clearly perceptible scrub, while 20 µm is closer to a polishing feel and is easier to keep in suspension in a surfactant base. K15 at 150 µm and oil absorption 300 is used where you want the same size with much higher oil uptake, for example in a cleansing balm.

These are the same chemistry as the cosmetic grades, so from a documentation point of view there is no separate category to qualify.

Not necessarily. It means the powder takes up more oil in a beaker, which is a formulation property and only an indicator of what happens on skin.

On skin, oil control depends on how much powder is actually on the surface, how well it stays there, and whether the formula lets sebum reach it. A very high-absorption grade at low loading can control less oil than a mid grade at higher loading. It can also make the film feel tight, which users often read as dryness rather than control.

Use oil absorption as a starting filter and confirm the real effect in a wear test. That is also why the same oil-control brief can be met by several different grades.

Drop the oil absorption first, then the loading, then add back slip.

High-absorption silica removes part of the oil phase along with the sebum, so the film ends up under-plasticised. Moving from a 300 grade to a 200 or 150 grade at the same loading often fixes it without touching the rest of the formula. If you must keep the grade, reduce the loading and make up the oil control with a platy filler.

Slip is the second lever: a small addition of boron nitride or mica restores glide and offsets the dry, draggy feel without giving back the oil control.

Wet it out before it goes into the main batch, and keep the shear high enough while it disperses.

Spherical porous silica has a large internal pore volume, so it pulls binder and oil into the pores quickly and forms lumps that are hard to break down later. Adding it into a portion of the oil phase first, or under higher shear than the rest of the batch, usually resolves it. Adding it last into a low-shear batch is the most common cause.

If agglomeration appears only after storage rather than during making, the cause is usually insufficient wetting rather than the grade, and changing grade will not fix it.

COA per lot, TDS and SDS are the baseline. Beyond that, the requirement depends on the form and on how the customer's own product is classified.

Two questions come up most often. First, whether the material counts as a nanomaterial for the customer's market — that depends on the particle size distribution of the specific grade, so it has to be answered per grade against the definition in force, not per product family. Second, crystalline silica content, which customers ask about for inhalation and labelling reasons; amorphous grades are specified and reported separately from crystalline.

As with any regulatory answer, tell us the destination and the wording your customer uses, and we will tell you which parts we can support from the batch documents.

It can support the claim, but it is not a texture-for-texture swap.

Talc is platy and provides slip plus moderate oil absorption. Spherical silica provides oil absorption plus ball-bearing glide and soft-focus, and it does not give the same coverage or compact strength. In practice a talc-free formula uses silica for oil control and soft-focus, and mica or boron nitride for slip and structure, with a binder review afterwards.

The claim itself needs checking against the market's rules — some markets define talc-free and asbestos-free differently, and a substitution that is technically sound can still need a specific statement or test report.

Stocked standard grades move quickly at sample scale; the commercial quantity and lead time are quoted per grade and destination.

The wide grade range — OA from 60 to 300, size from 2 to 200 µm — means not every code is held at the same level, and a code that needs a production run is where timing is decided. If you have a launch date, include it with the sample request so the schedule is built around the grade you will actually use.

Samples go out first so you can confirm the grade in your own formula; the quote follows the confirmed grade rather than the catalogue number.