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Tovex (also known as Trenchrite, Seismogel, and Seismopac) is a water-gel explosive composed of ammonium nitrate and methylammonium nitrate that has several advantages over traditional dynamite, including lower toxicity and safer manufacture, transport, and storage. It has thus almost entirely replaced dynamite. There are numerous versions ranging from shearing charges to aluminized common blasting agents. Tovex is used by 80% of international oil companies for seismic exploration. ==History== The Tovex family of products, sometimes generically called "water gels," were developed by the old Explosives Department at DuPont (E.I. du Pont de Nemours & Company, Inc.) in the mid-to-late 1960s when pelletized TNT was included in aqueous gels to create a slurry form of ANFO that displayed water-resistant properties in wet bore holes.〔E. I du Pont de Nemours & Company. Blasters' Handbook. Fifteenth Edition, 1966, p. 68.〕 TNT-sensitized water gels were commercially successful, but the TNT led to problems with oxygen balance: namely elevated amounts of combustion by-products such as carbon monoxide and nitrogen-dioxide complexes. Not only was TNT "dirty," it was also expensive. TNT was eliminated through the work of DuPont chemists Colin Dunglinson and William Lyerly and a team of others at DuPont's Potomac River Development Laboratory (PRDL) at Falling Waters, West Virginia, and at DuPont's Eastern Laboratories (EL) at Gibbstown, New Jersey. These chemists and engineers formulated a series of water gel-base products that replaced the TNT with methyl ammonium nitrate, also known as monomethylamine nitrate, or PR-M, (which stands for "Potomac River – monomethylamine nitrate"), creating the "Tovex Extra" product line. In late 1973, DuPont declared "the last days of dynamite" and switched to the new Tovex formula. The "Tovex" (that replaced nitroglycerin-based dynamite) had evolved into a cap-sensitive product. Even though it bore the same name as the earlier "Tovex," it was quite different from the precursors, which could only be initiated in large diameters (5 inches) with a one pound TNT booster. The new Tovex of the mid-to-late 1970s could be detonated in (critical) diameters much smaller than 5-inches by utilizing DuPont's Detaflex, thus making the new Tovex a realistic replacement for dynamite. Until then, only nitroglycerin-based explosives were commercially feasible for blasters who wanted cap-sensitive explosives that could be initiated with a #6 blasting cap in bore holes as small as 3/4 of an inch in diameter, sometimes less. The new Tovex satisfied that requirement. Atlas, Hercules, IRECO, Trojan-US Powder and several other explosives manufacturing firms of the era created emulsions, gels and slurries which accomplished the same end, but it was the DuPont patent of PR-M based explosives () that gave the DuPont Company a competitive edge. DuPont stopped producing nitroglycerine-based dynamite in 1976, replacing it with Tovex. In 1980, it sold its Tovex technology to Explosive Technology International (ETI), a Canadian company. One ETI licensee is Biafo Industries Limited, headquartered in Islamabad, Pakistan. As of this writing, explosives sold under DuPont's original "Tovex" trade name are distributed in Europe by Societe Suisse des Explosifs, Brigue, in Switzerland.〔Kohler, Josef and Rudolf Meyer, ''Explosives'', 4th edition, p. 377. ISBN 1-56081-266-4 (VCH Publishers).〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Tovex」の詳細全文を読む スポンサード リンク
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