Additives, especially inorganic solid particulates, have greatly contributed to the growth of the polymer industry. They render polymers with improved mechanical, physical, electrical, thermal and dimensional properties, depending on their geometry and chemistry. Glass bubbles are finely dispersed, free-flowing powders consisting of thin-walled (0.5-1.5µm) spherical glass particles with an average diameter of 15-65µm.

Glass bubbles were developed in the 1960s as an outgrowth from the manufacture of solid glass beads. They are commercially manufactured by melting a unique glass formula that contains a latent blowing agent causing the molten glass particles to expand into a hollow bubble. The resultant glass bubbles are chemically stable, water resistant and compatible with many materials used for indirect food contact applications. The material technology has evolved in recent years to produce bubbles with a high strength to density ratio which enables their use in demanding polymer processing operations.

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