Trimethylsiloxysilicate (MQ Resin)

Trimethylsiloxysilicate (CAS 56275-01-5) is a silicone resin built from trimethylsiloxy (M) and silicate (Q) structural units — the material formulators know as MQ resin. It is a film former. Dissolved in a volatile silicone carrier and applied, its three-dimensional siloxane network dries down to a continuous, flexible film that anchors pigments and actives to the surface and resists water, sweat, and rub-off. That single property is why MQ resin sits at the core of nearly every long-wear, transfer-resistant, and water-resistant claim in modern personal care.

The performance comes from the structure. Linear silicone fluids spread and lubricate but do not set; the Q (silicate) units cross-link the M (trimethylsiloxy) chains into a rigid 3D cage, so an MQ resin behaves more like a hard silicone film than a fluid. Raise the resin fraction in a formula and the film gets harder, more durable, and more transfer-resistant — but also less flexible and tackier to handle. That trade-off between wear and feel is the lever formulators actually tune, which is why MQ resin almost always ships pre-dissolved at a defined solids level rather than as a raw flake you have to cut yourself.

Applications by sector

Long-wear color cosmetics

This is the anchor application. In foundations, lipsticks, eyeliners, and mascara, MQ resin lays down the transfer- and smudge-resistant film that lets a product survive a meal, a mask, or a workday. The resin locks pigment in place, so color stays on the face instead of migrating to a cup or a collar. It is oil-soluble and pairs cleanly with volatile silicones and isododecane, the carriers that flash off and leave the durable film behind. Loading is the dial: more resin buys wear and non-transfer, less keeps the finish comfortable and non-tacky.

Sun care

In sunscreens and after-sun, MQ resin is used to improve the water and wash-off resistance of the film that carries the UV filters. A more durable, rub- and rinse-resistant film helps the protective layer stay on skin through water and sweat exposure. We make no SPF or efficacy claim here — the resin is a film-forming aid; substantiation of any sun-protection performance is the formulator’s, validated by standard in-vitro/in-vivo testing.

Skin care

Beyond color, MQ resin shows up in primers, BB/CC creams, protective and barrier creams, and oil-control bases. The siloxane film is breathable and permeable rather than occlusive-sealed, which is what lets it deliver a smooth, non-greasy slip and a soft-focus or gloss finish while resisting sebum and perspiration. In mattifying and “long-wear base” products it helps hold the rest of the formula in place under oil and humidity.

Hair

In styling sprays, gels, and serums, the same film provides hold, shine, and humidity resistance — the film resists moisture pickup, so a set holds in damp conditions, and the silicone surface adds gloss and a smooth feel without heavy build-up. It also contributes body and volume in leave-on hair products.

Antiperspirant and deodorant

In sticks, soft-solids, and roll-ons, MQ resin is used as a film former to improve the wear and water/sweat resistance of the applied layer and to modify the deposit’s feel — the same durable-film mechanism, applied to a high-humidity, high-friction use.

Forms and grades

Although trimethylsiloxysilicate itself is a solid resin, formulators rarely buy it dry. It is most often supplied pre-dispersed as a solution in a volatile silicone carrier — commonly cyclopentasiloxane (D5) or another volatile/cyclomethicone — or in a non-volatile carrier such as dimethicone or caprylyl methicone when a longer-lasting emollient feel is wanted. The two specs that define a grade are the carrier and the resin (solids) percentage; the solution form is what flashes off cleanly and lays the film. Solid flake resin is also available where a formulator wants to dissolve it into a specific carrier in-house. We do not publish a fixed solids figure here because it is grade-dependent — specify your target carrier and solids, and the Certificate of Analysis (CoA) and SDS will confirm the as-supplied form.

Handling

The Safety Data Sheet for the specific grade governs all handling, storage, PPE, and disposal. Volatile-silicone-carried solutions carry the flammability and ventilation considerations of the carrier, so route handling decisions through the CoA and SDS for the exact material shipped rather than any general description on this page.

Bulk sourcing

RawSource sources trimethylsiloxysilicate (MQ resin) in bulk for cosmetic and personal-care manufacturers — solution-in-carrier or solid flake, in drums, totes, and IBCs. Tell us your target carrier (D5, dimethicone, isododecane, other), resin solids, and volume, and we will source to your spec and quote it. Request a quote.