Polymethylsilsesquioxane (PMSQ)

Polymethylsilsesquioxane (PMSQ) – Spherical Silicone Resin Powder for Soft-Focus and Matte Finish

Basic Information

• CAS Number: 68554-70-1

• Molecular Formula: [–Si(CH₃)O₁.₅–]ₙ

• Molecular Weight: 7,000–8,000 g/mol

• Appearance: White to off-white fine powder

• Particle Size: 4–10 µm (depending on grade)

• Melting Point: >999°C

• Solubility: Practically insoluble in water and organic solvents; dispersible in oils and silicones

• Storage: Store in a cool, dry place, protected from moisture and direct sunlight

Overview
Polymethylsilsesquioxane (PMSQ) is a three‑dimensional silicone resin polymer formed by the hydrolysis and condensation of methyltrimethoxysilane. It is supplied as a spherical micro‑powder with a highly crosslinked structure. This unique morphology provides exceptional sensory and functional benefits in cosmetic formulations, making it a popular choice for skin care, color cosmetics, and sun care products.

Physicochemical Properties

• Spherical particle shape: Provides smooth, lubricious feel and excellent flowability.

• Soft‑focus effect: Spherical particles scatter light, visually blurring fine lines, wrinkles, and imperfections.

• Sebum absorption: Porous structure absorbs excess oil, reducing shine and providing a matte finish.

• Water repellency: Hydrophobic surface provides water resistance and improves product durability.

• Film‑forming: Forms a lightweight, breathable film that locks in moisture and protects the skin.

• Texture enhancement: Improves spreadability, slip, and sensory feel, reducing tackiness and powder agglomeration.

• Pigment dispersion: Prevents pigment and powder clumping, improving color uniformity.

Applications

• Color cosmetics: Foundations, powders, primers, blushes, eyeshadows, and lip products – provides matte finish, soft‑focus effect, improved spreadability, and extended wear.

• Skin care: Moisturizers, sunscreens, and anti‑aging creams – adds silky feel, controls shine, and enhances skin appearance.

• Hair care: Dry shampoos and styling powders – absorbs oil and adds volume.

• Other: Used as an antiblocking agent and slip agent in coatings and polyolefin films.

Key Benefits

• Creates a soft‑focus, blurring effect for a more even skin appearance.

• Absorbs excess sebum and provides a long‑lasting matte finish.

• Imparts a silky, smooth, non‑greasy feel.

• Improves spreadability, pigment dispersion, and reduces powder agglomeration.

• Enhances water resistance and product durability.

• Lightweight, breathable, and non‑comedogenic – does not clog pores.

• Compatible with a wide range of cosmetic ingredients.

• Thermostable and chemically inert.

Recommended Use
Typical usage levels range from 1–10% of the formulation, depending on the desired texture, oil absorption, and matte effect. For optimal dispersion, incorporate into the oil or powder phase with moderate mixing. Can be combined with other powders, pigments, and film‑formers for tailored performance.

Safety and Handling

• Generally recognized as safe for use in cosmetics at recommended concentrations.

• Low irritation potential; well‑tolerated by skin.

• Avoid inhalation of dust – use appropriate personal protective equipment (gloves, dust mask, safety goggles).

• Store in a cool, dry place, away from direct sunlight and moisture.

• Shelf life: typically 24 months under recommended storage conditions.

Quality Assurance
Each batch is tested for particle size distribution, purity, and oil absorption capacity to ensure consistent performance.