Microsphere refers to a spherical microparticle between 1 and 1,000 microns (μm) in diameter. Also known as spheres, balls, beads or micro-balloons, microspheres are manufactured from a variety of raw materials. The most common types are solid and hollow glass or polymer microspheres, as well as ceramic. Each type is designed in different grades depending on the application and quality requirements. The quality of the microspheres ranges from monodispersed microspheres produced under tight specifications, to microsphere grades with variations in particle size and sphere uniformity.
Glass, polymer and ceramic microspheres are well-known in the cosmetics and personal care industry for advantages such as sensorial benefits and optical effects, among others. Their spherical shape and smooth surface create a low friction ball-bearing effect that gives formulations an elegant, silky feel. This ball-bearing effect promotes better blending on the skin and a more natural finish due to the enhanced slip, glide and omnidirectional spreadability, imparting a cream to powder texture. Outstanding roundness also provides lubrication during application, which enhances the tactile experience of a cosmetic product.
In addition to enhancing the feel and appearance of skin, the appropriate microspheres can minimize the appearance of fine lines and uneven skin tone. This is achieved due to microspheres’ ability to scatter light, an effect referred to as optical blurring or soft focus. Skin imperfections are visible due to high contrast. However, spherical particles have the capacity to optically reduce this contrast and hide imperfections on the skin surface by scattering or diffusing light. Since the microspheres optically blur lines and imperfections using light, the skin remains natural-looking.
Microspheres are also used as gentle exfoliators in facial scrubs. Round particles are known to be less irritating to the skin than irregularly shaped, abrasive exfoliants with sharp edges such as apricot kernels and walnut shells. The roundness and smoothness of microspheres therefore makes them gentle and effective exfoliating agents to remove dead cells without harming the skin. In addition, microspheres are commonly used as fillers/texture enhancers in pressed and loose powders, foundations, concealers, lipsticks, mascara, skin lotions and variety of other applications.
Colored Polyethylene Microspheres
A line of colored, solid polyethylene microspheres was recently developed via a proprietary process to produce polymer microspheres that are smooth, highly spherical, non-soluble in water and most solvents, and that withstand temperatures of up to 100°C. These spheres can be manufactured with specific gravities from 0.96 g/cc to 1.3 g/cc, which provides for optimal suspension in a solution. Solid polymer microspheres incorporate pigments and additives to achieve colorful fillers that serve multiple functions in a cosmetic formula by acting as colorant, opacifier and texture enhancer simultaneously.