17RU448-G_TDS.pdf

SILPAK RU-448
Performance Polyurethane Rubber
RU-448 A/B is a 45 shore A hardness, polyurethane RTV elastomer that cures to a rubber material with excellent
tear strength and abrasion resistance. It has a simple 1:1 mix ratio and low viscosity for easy processing.
Features
Excellent tear resistance and elongation Rapid mold cycle
e Easy to process
Applications
Applications include the following or any application where a flexible rubber part is required.
Concrete texture and stamp pads e Concrete form liners
e Rubber molds and parts e Prototype rubber parts
Physical and Handling Properties
Property Value
Color Yellow
Mix Ratio, by weight 1A: 1B
Initial Mixed Viscosity, cP 3,000
Hardness, Shore A 45
Gel Time, min 30
Demold Time, hr 16
Specific Gravity 1.02
Tensile Strength, psi 650
Elongation, % 800
Tear Resistance, pli 90
Values listed above are typical and not intended for use in specifications.
Proper Use and Safety
Read all instructions and safety data sheets prior to use. Consult safety data sheets for all recommended safety
precautions.
Master Preparation
Polyurethane RTVs will adhere to most surfaces. A proper mold release must be used on all surfaces. Silpak ER
2300 is recommended. Wood, plaster, stone, pottery, masonry or any porous surface must be sealed with lacquer
or clear shellac prior to applying release. PartAll Film #10 or shellac is suitable for sulfur and water-based clays.
Allow 24 hours to dry before preparing master with mold release. Plaster masters can release air when pouring
larger molds due to some heat generated. Venting the base of your master by drilling several % holes will release
the air downward to avoid air entrapment in the mold cavity. Polyurethane RTV cures to a flexible rubber at the
cure time noted above.
Silpak is a division of Polytek Development Corp. – www.silpak.com – 800.858.5990 – 55 Hilton Street, Easton, PA 18042