In London's Natural History Museum, the Earth Galleries are supported by Rio Tinto, corporate parent of U.S. Borax. These halls celebrate the world's minerals heritage and the benefits it has brought. Early in the tour, before an escalator ride through Earth's geological history, a sharp-eyed visitor might pause to consider a prehistoric example of a modern-looking material. It is glass fiber, which in nature is a rare phenomenon but today is an everyday industrial product. Fiberglass is a fusion of a commonplace mineral, and one—boron—which is very scarce except in a very few places on Earth.
Origins of fiberglass: From goddess hair to e-glass
When strong winds blow across the surface of molten lava gushing out of volcanoes, gossamer-fine strands of clear glass can be formed to weave and tangle and catch in masses on the hillside. This is what ancient civilizations called goddess hair,
a handful of which is displayed in South Kensington, London. It bears an uncanny resemblance to modern manufactured fiberglass. One difference is that it probably contains no boron at all, unlike today's insulation or reinforcement fiberglass.
In the 1940s, a glass recipe was patented which, with a procession of derivatives, was to revolutionize industry, industrial manufacturing, consumer products, and indeed the whole of technology itself. The patent named the material e-glass.
It was a high-boron glass formulation from which fibers could be drawn that were long and continuous with good chemical and water resistance and of minimal electrical conductivity. Today, this fiberglass material is considered an intermediate product and is almost unnoticed by consumers. However, it is of pervading importance.
E-glass or fiberglass has thousands of end-use applications. It is particularly important as a highly effective and low-cost reinforcement of plastics, resins, and other materials which by themselves could not do the job intended. As such, it offers low weight, high corrosion resistance, great strength, and vast adaptability.
Today, the e-glass of that 1940s patent goes by several names:
- Continuous strand fiberglass
- Glass mat
- Glass fiber or glass composite
- Fiber reinforcement
- Textile fiberglass (TFG)
Basic TFG material from the fiberizing plant has considerable versatility. It can be spun into yarn, woven into fabrics and ribbons, made into rovings, or chopped and formed into mats.
Boric oxide: A non-sodium borate essential for non-conductive fiberglass
Most TFG—some four-fifths—produced around the world today is used in conjunction with plastics and resins. The other 20% is used by the construction industry for asphalt roof shingles, translucent roofing panels, and vinyl flooring tiles.
TFG fiber-reinforced plastics are used in thousands of applications, from marine uses—boat hulls, surfboards, and sailboards—to auto panels and parts and printed circuit boards. These diverse uses, perhaps oddly, share a need for reinforcement fibers that are low in sodium.
It really wouldn't do if your surfboard disintegrated on the crest of a wave. Nor would it be acceptable if the motherboard panel in your computer conducted electricity almost as well as the copper strips.
Ordinary glass—soda-lime silicate—contains sodium oxide which is important for melting the raw materials and lowering molten glass viscosity. Both functions are important to fiberizing, but soda in the fiber dissolves after continual immersion in water; it also weakens the fibers and makes them electrically conductive. Sodium oxide had to be replaced with an oxide that performs as well in the end application as it does during manufacture: Boric oxide (B2
The glass maker's choice of boric oxide feedstock is therefore limited to non- or low-sodium borates. Boric acid is the preferred raw material for many manufacturers as it meets all the criteria demanded. It is also more economical to transport and arrives furnace-ready, unlike unrefined minerals.
High-quality boric acid is refined from borate minerals by U.S. Borax facilities in Boron, California
, and Coudekerque, France
, locations that are well placed to serve the American, European, and international markets.
U.S. Borax-inspired logistics ensure also that borate demands from the manufacturing centers of the Pacific Rim, particularly for tightly-specified glass formulations, are well met by the ability to deliver the best borate for boards—both surf and circuit.
Boric Acid: Best for fiberglass
- High B2O3 content
- Furnace-ready borate
- Good consistency, regularity, and reliability
- Batch flexibility
- Low-pollutant impurities
- Low surface tension and high viscosity at low temperatures (1000ºC), facilitating raw materials melting