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DESCRIPTION ISONEL 31-398 is a general-purpose, modified polyester varnish for conventional dip and bake application. Specially formulated for use in abbreviated baking cycles, it cures quickly to a clear, tough, semirigid film. ISONEL 31-398 provides excellent performance and economy in Class A (105 C) through Class H (180 C) design applications. ISONEL 31-398 is certified as meeting all requirements of military specification MIL-I-24092 for Grade CB, Composition I, Class 155. RECOMMENDED USES ISONEL 31-398 is designed for general-purpose application on transformers, stators and armatures. PHYSICAL PROPERTIES Viscosity at 77F(25 C) Zahn #2 (seconds) 95-135 Centipoises 275-370 Specific Gravity at 77F(25 C) 0.920-0.935 Solids Content, % 46-50 Flash Point (ASTM D 56-70, F/C) 85-29 Viscosity Reducer Xylol CURE CYCLE ISONEL 31-298 cures in one to two hours at 275-325F(135-163C), the actual cycle depending on oven efficiency and the weight and shape of the treated unit. CURED FILM PROPERTIES Electrical - Dielectric Strength (ASTM D 115) on copper Dry - 4150 Volts/Mil Wet - 3050 Volts/Mil Mechanical - Helical Coil Bond Strength (ASTM D 2519 on MW-35) 77F (25 C) - 45.0 Pounds (20.5kg) 302F (150 C) - 4.0 Pounds (1.8kg) -Weight Loss (ASTM D 2756-68) 48 hours at 392F (200 C) - 7.7% 98 hours at 392F (200 C) 10.6% U.L. 1446 THERMAL ENDURANCE (based on 20,000 hours intercept) Twisted Pair Helical Coil MW-16 220 180 MW-24# 155 180 MW-28 130 155 MW-30 180 200 MW-35 180 200 ISONEL 31-66 - ISONEL 31-398 in a "Rule 66" (nonphotochemically reactive) solvent system. ISONEL 31-66HF-ISONEL 31-398 in a high-flash point, "Rule 66" (nonphotochemically reacive) solvent system. ISONEL 31 Black-ISONEL 31-398 with a black pigment, particularly suited for exterior finishes.
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