A Transparent Millable Polyurethane Rubber
Millathane 97 is a polyether millable urethane rubber having excellent wear properties, a high coefficient of friction and very good UV stability. This polyurethane rubber is designed for applications in shoe soling, roll coverings and other applications where transparency in brightly colored or decorative products is required.
|Chemical Composition:||Synthetic rubber based on ether/aliphatic diisocyanate|
|Specific Gravity:||Approximately 1.02 g/cc|
|Mooney Viscosity:||40 to 80 ML 1+4 @ 100º C|
|Appearance:||Clear to slightly amber bales|
|Package:||38 pounds per box|
|Storage stability||3 years when stored under dry and cool conditions|
Millathane 97, like other millable urethanes, is processed by techniques which are common to the rubber industry. Compounds can be mixed on an open mill or in an internal mixer; molded articles can be produced via compression, transfer or injection molding; calendered sheets can be press cured or rotocured or vulcanized in steam or hot air autoclaves. See TIPS V3-1 (to the right) for Injection Molding of Millathane 97.
For a video of Millathane 97 mill mixing, go to the Millathane download page.
Millathane 97 is peroxide-curable only, and Varox/Lupersol 231 or DiCup R are generally used. Coagents such as SR231 (DEGDMA) and/or SR350 (TMPTMA) from Sartomer are commonlyused to improve cure rates and physical properties. They also improve processing because they are liquid materials.
Millathane 97 requires reinforcing fillers to achieve hardness and high mechanical strength. A reinforcing filler like fumed silica is typically used to achieve clear compounds, and is easily incorporated into Millathane 97. Antioxidants such as Irganox 1010, Anox 20 or Anox 1315 (from Ciba and Chemtura, respectively) should be added at 0.25-0.5 parts and UV stabilizers also used if products will be used outdoors. The combination of Anox 1315, Lowilite 62, and Tinuvin 328 (Chemtura and Ciba products) gives very good resistance to yellowing and resistance to ultraviolet (UV) light
Vulcanizates based on Millathane 97 can be produced in hardnesses ranging from 45 to 95 Shore A durometer, and offer exceptional clarity, outstanding abrasion resistance, good chemical resistance and an excellent hydrolysis resistance. Millathane 97 shows an improvement in low temperature flexibility and wet traction compared to previous grades of clear polyurethane rubber.
Compounds based on Millathane 97 are vulcanized at temperatures of 145º - 165º C, depending on the peroxide used, with typical curing times of compression molded lab sheets being 5 to 10 minutes.
(See the Millathane Formulary for other compound examples)
|Wacker HK-N20 fumed silica||30.00|
|Lupersol231 (or Varox 231)||0.40|
|Cure Time, minutes||10|
|Cure Temperature||150º C|
|Hardness, Shore A||70|
|100% Modulus, MPa (psi)||2.6 (377)|
|200% Modulus, MPa (psi)||5.7 (825)|
|300% Modulus, MPa (psi)||10.1 (1460)|
|Tensile Strength, MPa (psi)||26.1 (3780)|
|Elongation at break, %||490|