Surfing Waves And Web On Borosilicate Glass
February 1998

In London's Natural History Museum the new Earth Galleries, which are supported by Rio Tinto, Borax's corporate parent, celebrate the world's - and so mankind'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 with maybe more than normal insight might pause to consider a prehistoric example of a most modern material. It is glass fiber: in nature, a rare phenomenon, but now an everyday industrial product, a fusion mainly of a commonplace mineral, and one, boron, which is very scarce except in a very few places on Earth.

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 'goddesses' hair', a handful of which is displayed in South Kensington, London. It bears an uncanny resemblance to modern, manufactured, fiberglass. One difference - it probably contains no boron at all, unlike today's insulation or reinforcement fiberglasses.

Fifty-five years ago a glass recipe was patented which, with a procession of derivatives, was to revolutionize industry, industrial manufacture and consumer products, and indeed the whole of technology itself. The patent dubbed it 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, as an 'intermediate' product it is almost unnoticed by consumers, but is of pervading importance.

With probably many thousands of end-use applications, it has but one overriding vocation: to be 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 1940's patent goes by several names: continuous strand fiberglass, glass mat, glass fiber or glass composite, fiber reinforcement, or textile fiberglass (TFG). The basic 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.

Most TFG - some four-fifths - produced around the world today is used in conjunction with plastics and resins. The other 20 percent is taken up by the construction industry for asphalt roof shingles and translucent roofing panels, and vinyl flooring tiles.

The fiber-reinforced plastics number many 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 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 are important to fiberizing, but soda in the fiber dissolves after continual immersion in water and weakens the fibers, and it also makes them electrically conductive. It had to be replaced with an oxide that performs as well in the making as it does in the use: boric oxide, B2O3.

The glass maker's choice of B2O3 feedstock is therefore limited to non- or low-sodium borates. Boric acid is the preferred raw material for many users as it meets all the criteria demanded. "Boron for boron" it is more economical to transport than unrefined minerals as well as being furnace-ready.

High-quality boric acid is refined from borate minerals by Borax facilities in California, U.S. and at Coudekerque, northern France, locations which are well placed to serve the American, European and international markets.

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 melting raw materials.