Development of Alternate Silicone Potting Compounds. Vol. 3. Development of Substitute No. 1 for Dow Corning's Aerospace Sealant, DC 93-120

摘要

A substitute for DC 93-120 aerospace sealant can be formulated by blending Sylgard 184 with Sylgard 186 and accelerating the blend with accelerator XCF3-6559 to achieve our goals of an initial viscosity of 10 Pa.S at 25 exp 0 C and a gel time of 90 min at 25 exp 0 C. One lot of Sylgard 184 was evaluated with two lots of Sylgard 186 of slightly differing catalyzed viscosities and gel times. Three combinations of Sylgard 184, Sylgard 186, and accelerator were formulated and evaluated; these combinations met goals of viscosity, gel time, and extractables of less than 6 wt%. The two Sylgard 186's required slightly different amounts of Sylgard 184 to achieve a viscosity of 10 Pa.s.. The gel time was achieved with 5-6 parts of accelerator per 110 parts of blend. At 6 parts of accelerator, the difference in the cure rate of the two lots of Sylgard 186 became insignificant. (ERA citation 03:055539)