I/EC
REPORTS
these new materials lies in the ability to check potted components visually in cases of their malfunctioning. Probes can be inserted for electrical tests. A faulty part can be dug out with a knife, replaced, and the hole filled with new material which cures to form an invisible repair. GE calls its new product LTV602 (specific gravity 0.995), and compares it in some respects to silicone rubbers which vulcanize at room temperature. But Dow Corning terms its Sylgard 182 (specific gravity 1.05) a flexible resin and definitely not a rubber. Both products, however, consist of twopart systems (solvent-free liquid silicone and liquid catalyst) which cure without fumes at temperatures ranging from 25° to 150° C , depending upon thermal sensitivity of the potted parts and volume of the compound being used. At room temperature, both materials cure in 3 days. For typical use, Dow Corning suggests a curing cycle of 4 hours at 65° C. for Sylgard 182 to give a tough, resilient, yet flexible product. At 150° C , cure occurs in 15 minutes. GE recommends 16 hours at 75° to 80° C. as a normal oven cure for LTV-602, noting that a few hours post cure will increase firmness and improve high temperature properties. In general, says GE, its product provides physical and electrical protection to potted components continuously at 150° C , for over 3000 hours at 175° C , or for 1000 hours or more at 200° C. Dow Coming's Sylgard 182, calling for 10 parts of curing agent per 100 parts resin, forms a light-strawcolored mixture (which becomes colorless during cure) with roomtemperature viscosity of 5000 cp. and a pot life of 6 hours. Only 0.25 part of the GE SRC-04 catalyst is needed for 100 parts of LTV-602, to give a mixture having viscosity of 800 to 1500 cp. and an 8-hour pot life at 25° C. Obviously, rockets and missiles form a prime market for this new type of material. But its intriguing characteristics should lead into a number of valuable industrial uses, and possibly consumer novelty applications as well. D.G.W.
Facts Worth Noting on QO* TETRAHYDROFURFURYL ALCOHOL QO
QO
T H F A * is a starting point for such compounds as pyridine, 4-hydroxyvaleraldehyde, lysine, 5-(2-tetrahydrofuryl) hydantoin, and glutaric acid. is an excellent solvent for resins, gums, dyes and THFA* complex organic compounds. Its high boiling point and complete miscibility with water are additional unique characteristics as a solvent.
Q O T H F A * is a driver for leather dyes producing deep penetration and fine leveling of spray or flame coats. Q O T H F A * ester if ies readily and is used in the production of high boiling plasticizers. If you too w o u l d like more information on the chemistry, physical properties a n d uses of Q O THFA, w r i t e f o r Bulletin 206-A.
The Quaker Qa\s (pmpany CHEMICALS
The Quaker Oats Company
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DIVISION
337S The Merchandise Mart, Cnicago 54, Illinois Room 537S, 120 Wall Street, New York 5, New York Room 437S, 48, S.E. Hawthorne Blvd., Portland 14, Oregon In t h e United Kingdom! Quaker Oats Ltd., Southall, England In Europe: Quaker Oats-Graanproducten N. V., Rotterdam, The Netherlands; Quaker Oats (France) S. A., 3, Rue Pillet-Will, Paris IX, France; A / S " O t a , " Copenhagen, S. Denmark In A u s t r a l i a : Swift & Company, Ltd., Sydney In Japan: F. Kanematsu & Company, Ltd., Tokyo Circle Nt. 23 on Readers' Service Card VOL.
53, NO. 4
•
APRIL 1961
39 A
