Sandpaper
Spring cleaning is often accompanied by a wealth of do-it-yourself projects using this ubiquitous abrasive.
Credit: iStock
Many consumer products owe their flawless finish to sandpaper. Technically referred to as a coated abrasive, sandpaper is used during the manufacturing of everything from aluminum baseball bats to orthopedic implants.
In the 13th century, the Chinese created some of the earliest forms of sandpaper by crushing seashells and bonding them to parchment paper using natural gums. By contrast, modern sandpaper production is a highly sophisticated process.
“From a layman’s perspective, you might think that you just sprinkle little rocks on a backing, but there’s a lot of science behind sandpaper,” says Stefan A. Babirad, technical director at 3M Abrasives Systems Division. To design sandpaper, researchers must consider the chemical properties of the abrasive material and the adhesive, which is then attached to a backing made of paper, cloth, or polymeric materials.
The abrasive can be a natural mineral such as garnet or emery or a synthetic material such as fused aluminum oxide or silicon carbide. Synthetic abrasives are much harder and tougher than natural minerals and have emerged in the 20th century as the material of choice for the industry, Babirad says.
Next come the adhesives. For most do-it-yourself sanding applications, adhesives can be animal-hide-derived glues, while stronger polymeric bonding agents such as urea formaldehyde, acrylic, and epoxy resins are used for more aggressive sanding. Phenolic resins are the adhesive heavyweight champions because they can withstand the high temperatures and frictional forces generated during heavy-duty industrial sanding.
Visit “What’s That Stuff” to read more about the chemistry of sandpaper.
Excerpted with permission, Chemical & Engineering News
Copyright © 2007 American Chemical Society