3M™ Glass Bubbles K37 are lightweight hollow glass microspheres with a density of 0.37 g/cc and a crush strength of 3,000 psi. These general purpose spheres offer very good strength-to-density ratio and making them suitable for a variety of uses – coatings, adhesives, mastics, sealants and thermoset resin systems.
What are 3M™ Glass Bubbles?
The general purpose K Series glass bubbles are the most versatile and economical 3M™ Glass Bubbles. Our 3M™ Glass Bubbles K37 are engineered hollow glass spheres made from water-resistant and chemically-stable soda-lime borosilicate glass. Like all 3M glass bubbles, our K37 glass bubbles are water and oil resistant, providing better utility in underwater applications and creating more stable emulsion explosives. Additionally, they are non-combustible and non-porous, so they do not absorb resin; and their low alkalinity makes this product compatible with most resins while providing a stable viscosity and a long shelf life.
3M glass bubbles are a superior alternative to many conventional fillers and additives such as silicas, calcium carbonate, talc, clay and other materials used in demanding applications. Our low-density spheres are used in a wide range of industries to reduce part weight, may lower costs and enhance product properties – making them more reliable and affordable than many alternatives such as cenospheres and perlite.
The benefits don’t end there; although these hollow spheres have thin walls, they have an isostatic crush strength of 3,000 psi making them suitable for a number of applications. In addition to paints and coatings, these bubbles may be used for compounding, rubber and plastic applications. K37 bubbles have a fractional survival rate of 80% or more, at 3,000 psi for consistent performance and greater survivability. This is especially important in the production of plastic and rubber parts, so you can reduce the weight of finished parts without compromising the strength and mechanical integrity.
The unique spherical shape of these bubbles offers a number of additional benefits, including: higher filler loading, lower viscosity/improved flow and reduced shrinkage and warpage. Higher filler loading offers the potential for lower costs. Adding to this product’s versatility is its ability to be easily blended into compounds – making it adaptable to a variety of production processes including spraying, casting and molding.
Buoyancy Benefits and Applications
The ideal combination of high strength and low density has made 3M glass bubbles an industry-standard additive for syntactic foams used in buoyancy modules, buoys or buoyancy blocks for undersea vehicles. When 3M glass bubbles are formulated with resin, the resulting syntactic foam has a high strength-to-density ratio to provide maximum net buoyancy for a given depth rating. The bubbles also produce stable voids, which results in low thermal conductivity and low dielectric constant.