Scotchlite™ Glass Bubbles
Glass bubbles incorporated into emulsion formulations as a sensitizing agent can improve blast
efficiency and relizbility. A broad range of densities and strengths are available to match a wide range
of slurry and emulsion requirements.
Industrial Explosives
For over twenty years 3M™ Glass Bubbles have been the density modifier of choice in bulk emulsion,
packaged emulsion, water gel and slurry explosives.
It’s the sensitizer, as studies have proven, that in large part determine the effectiveness of an explosive
charge, providing the internal voids crucial to efficient detonation. And that’s essentially all a 3M glass
bubble is: a spherical, strong, low density, pre-manufactured void.
By using 3M glass bubbles, explosive manufacturers often obtain an immediate increase in velocity of
detonation (VOD). The excellent fragmentation provided by high VOD can mean:
•
•
•
•
Reduced secondary blasting
Reduced energy consumption
More tons per hour processed
Lower cost per ton of rock moved
In addition, 3M™ Glass Bubbles offer stable, consistent performance over a wide timeframe:
•
•
•
•
•
Pre-manufactured voids mean highly consistent, repeatable performance
Rigid-walled, hollow spheres give explosives stability over time, temperature and pressure
Discrete particles allow easy addition and uniform distribution
Non-coalescing voids allow longer “sleep” time
Wide range of available sphere strengths minimizes dead pressing
Bulk Emulsion Explosives
Because dead pressing is not a major concern in bulk emulsion explosives, an extremely high-strength
glass bubble is typically not necessary. Instead, high VOD and stable, consistent performance can be
achieved with a more economical, lower density 3M™ Glass Bubble.
Packaged Emulsions
For the tightly-packed detonation patterns commonly utilized to blast through hard rock, dead pressing
is an important issue. 3M recommends using a glass bubble sensitizer strong enough to
survive a nearby detonation
Slurry Explosives
Because dead pressing is a major concern with slurry explosives, 3M recommends stronger 3M™
Glass Bubbles for use as sensitizers. These high performance bubbles provide some of the industry’s
highest VOD - directly contributing to a lower cost per ton of rock moved.
Water Gel Explosives
These high performance explosives require a high performance sensitizer. 3M™ Glass Bubbles provide
outstanding VOD for high fragmentation and are stable day-to-day, month-to-month. Recommended
bubbles have high strength to minimize dead pressing.
Inside Glass Bubbles
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.
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.