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The use of 3M™ Glass Bubbles as sensitizers in explosive applications is well-established. Glass bubbles provide stable, strong, pre-manufactured voids that contribute to higher velocity of detonation (VOD) and consistent detonation performance. But these tiny spheres are used in vastly different ways in many different industries.
What is a glass bubble? 3M glass bubbles are manufactured through a multi-step process in which glass is formed at high temperature from soda-lime-borosilicate, milled to fine particle size, and then run through a high-temperature heat transfer process.
During this process the viscosity of the glass drops to a level at which surface tension causes the particle to form a perfect sphere. High temperature then causes a latent blowing agent in the glass to decompose to a gas, and the pressure of this gas causes the particle to expand from a small, solid sphere to a larger, hollow sphere. This trapped gas is at approximately one-third atmosphere, greatly contributing to the low density of 3M™ Glass Bubbles. |
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What do they do? In explosives, the low density glass bubbles help propogate the detonation wave allowing the reaction to continue.
In other applications, glass bubbles are valued for their extreme strength, low density and chemical inertness. They can offer products a variety of enhancements:
High filler loading
The lowest surface area to volume of any shape increases volume loading capacity.
Low viscosity
Acting like thousands of ball bearings, glass bubbles roll easily over one another.
Reduced dielectric constant
A natural insulator, they are especially useful in printed circuit boards.
Reduced warpage/shrinkage
In molded plastics, their high strength and spherical shape reduces warpage.
Machinability
The high strength of glass bubbles allows their use in injection molding.
Thermal insulation
Low thermal conductivity makes glass bubbles excellent insulators.
Buoyancy
Their low density and high strength is perfect for buoyancy applications at depth.
Weight reduction
Glass bubbles can be cost effective weight reducers in sealers, adhesives and molded plastic parts.
Low density fluids
In the oil and gas industry, glass bubbles are used to lower the density of drilling fluids and slurries.
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