XT-491
Product Information
General Information
XT-491 is a high tear, high tensile strength, tin catalyzed silicone designed to be used when casting polyurethane foam, polyester and epoxy parts. XT-491 is useful for applications where a flexible rubber with increased chemical resistance is required. When catalyzed with one of our library life extending catalysts (see supplemental products) and stored correctly, a longer life of the cured mold should be expected. Its high tear strength, elongation and tensile strength make it an excellent choice for any mold making application. It is also resistant to inhibition by most common mold making substrates, eliminating the need to use mold sealers.
Typical Properties
Uncatalyzed Compound
Color
Viscosity (cps) Mixing Ratio (B/A) Mixed Viscosity Working Time Cure Time
Shelf Life
Base: Off White Base: 50,000 - 70,000 By weight: 100 / 10 30,000 - 45,000
1 to 1.5 hours
16 - 18 hours
6 months
Activator: Blue Activator: 350-500
By volume: 100 / 11.1
Vulcanized (cured) Properties (7 days @ 70° F / 50% relative humidity)
Shore A Hardness (±3)
Tear Resistance (ASTM D624) Tensile Strength (ASTM D412) Elongation (ASTM D412) Service Temperature (° F) Shrinkage
Specific Gravity
Coverage (in3 / lb)
One day: 20 120 ± 10 ppi 525 ± 25 psi
300 ± 25 % -60 to 350
0.10 % 1.09 25.2
7 Days: 26
The information contained in this data sheet is, to our best knowledge, true and accurate, but all recommendations or suggestions are made without guarantee. Since the conditions of use are beyond our control, Silicones, Inc. disclaims any liability incurred in connection with the use of our products and information contained herein.
