A high-performance silicone resin wax that provides durable film-forming properties and a sophisticated, non-tacky skin feel. It excels at improving the wear-time of sunscreens and color cosmetics while enhancing the structural integrity of stick formulations.
- INCI Name:
- C30-45 Alkyldimethylsilyl Polypropylsilsesquioxane
- Chemical/Scientific Name:
- Silsesquioxanes, C30-45-alkyldimethylsilyl Polypropyl
- Common Aliases:
- Alkyl-modified Silicone Resin Wax, C30-45 Resin Wax
| Category: | Texture Enhancers |
| Source Origin: | Synthetic |
| Comedogenic Rating: | 0 |
| Primary Industries: | Color Cosmetics, Sun Care, Skin Care |
| Solubility: | Oil, Isododecane, and Silicone Soluble |
At a Glance: Properties & Effects:
| Texture Enhancement: | |
| Formula Stability: | |
| Barrier Repair: | |
| Irritation Risk: | |
| Comedogenicity: |
- Primary Benefits:
- Extends the wear-time of makeup and sunscreens by creating a flexible, breathable film.
- Provides a matte to semi-matte finish, reducing the greasy feel often associated with organic sun filters.
- Improves the transfer resistance of lipsticks and foundations.
- Increases the melting point and stability of stick-based products.
- Potential Risks:
- Requires oil-based cleansers for efficient removal due to its substantive film-forming nature.
- Does not provide significant biological “active” benefits like antioxidants or peptides.
Biological Action & Cosmetic Profile:
Molecularly, this substance is a specialty silicone resin where the silsesquioxane “T-resin” structure is modified with long-chain (C30-45) alkyl groups. While traditional silicones like Dimethicone offer slip and lubrication, the polypropylsilsesquioxane backbone provides a rigid, three-dimensional structure. This lattice-like architecture allows the ingredient to act as a potent film-former that adheres closely to the skin’s topography without migrating into fine lines.
The incorporation of C30-45 alkyl chains transforms the resin into a wax-like material at room temperature, which melts upon skin contact. This phase transition allows for a smooth application followed by the setting of a durable, water-resistant barrier. Unlike linear silicones such as Cyclopentasiloxane, which may evaporate, this resin remains on the skin to lock in moisture and keep pigments or UV filters in a uniform distribution.
In color cosmetics, this ingredient serves as a “fixative.” It prevents the smudging of products by decreasing the mobility of the oil phase in an emulsion. By optimizing the rheology of the formula, it ensures that high concentrations of Iron Oxides or Titanium Dioxide remain evenly dispersed during wear, preventing the “caking” or “breaking” of foundations over several hours.
Broader Applications & Origins:
Originally developed to bridge the gap between hard silicone resins and soft waxes, this ingredient is a mainstay in “all-day wear” cosmetic claims. It is synthesized through the hydrolysis and condensation of organosilicon precursors. Beyond its sensory benefits, it is frequently utilized in high-SPF sunscreens to maintain a consistent protective film even during perspiration or light water exposure. Because it is highly compatible with organic oils and Isododecane, it is a versatile tool for formulators looking to create anhydrous (water-free) balms and sticks.
Routine Integration:
- Synergies:
- Volatile Solvents: Works exceptionally well with Isododecane to create quick-setting, transfer-proof lip colors.
- Mineral Pigments: Enhances the suspension and even application of Mica and oxides.
- Emollients: Combines with Caprylic Capric Triglyceride to balance film durability with skin softness.
- Conflicts:
- Water-Only Cleansing: Formulations high in this resin will not be removed effectively with water alone; a double cleanse involving an oil-based cleanser or micellar water is recommended.
Clinical Consensus & Safety:
The Cosmetic Ingredient Review (CIR) Expert Panel and the European CosIng database recognize C30-45 Alkyldimethylsilyl Polypropylsilsesquioxane as safe for use in cosmetic products. Due to its high molecular weight and large spatial structure, it cannot penetrate the stratum corneum, rendering it biologically inert and non-irritating. Clinical studies on similar silsesquioxanes show no evidence of sensitization or comedogenicity, making it suitable for sensitive and acne-prone skin types.
Is this ingredient a “plastic” or microplastic?
No, this is a silicone-based resin wax. While it provides film-forming properties similar to certain polymers, it does not fall under the typical regulatory definitions of microplastic beads used for exfoliation.
Will it clog my pores?
Despite its “wax” description, silicone resins are non-comedogenic. They form a breathable film that allows gas and water vapor exchange, preventing the “suffocating” effect on pores associated with some heavy natural waxes or Petrolatum.
Why is it in my long-wear lipstick?
It provides the structural “backbone” that keeps the lipstick from feathering into the skin around the mouth and ensures the color stays on your lips rather than transferring onto cups or clothing.