A High Performance Millable Polyether Polyurethane Rubber
Millathane E34 is a high performance polyether millable urethane rubber which has been developed for applications requiring high abrasion resistance, low temperature flexibility, ozone resistance, oil and fuel resistance, outstanding hydrolytic stability and improved processing. Millathane E34 compounds also have high resilience (high rebound) characteristics.
Millathane E34 can be compounded and processed by the use of conventional rubber manufacturing equipment. Millathane E34 can be mixed on two roll mills or an internal mixer. Compounds can be calendered, extruded, or injection, transfer or compression molded to produce finished polyurethane parts.
Millathane E34 is typically vulcanized by the use of sulfur with thiazole accelerators and can also be vulcanized by organic peroxides such as dicumyl peroxide.
Millathane E34 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 or rotocured.
Millathane E34 compounds typically contain reinforcing fillers to achieve meet hardness and mechanical strength requirements, but gum compounds, with little or no fillers, have good properties. Reinforcing fillers like silica and small particle carbon black are easily incorporated into Millathane E34. It is sulfur or peroxide-curable, although the best properties are obtained with sulfur cures.
The best sulfur cure system is a combination of MBTS, MBT, Thanecure® ZM, and sulfur, with zinc stearate as an activator/process aid.
Any of the typical peroxides can be used for peroxide curing, including dicumyl peroxide and DBPH. Coagents, such as TMPTMA (SR-350, from Sartomer), are commonly used along with peroxides to modify hardness, processing and other properties.
TYPICAL POLYMER PROPERTIES
|Chemical type||Polyether polyurethane|
|Color||Pale amber to dark|
|Physical form||Solid bale or milled sheets|
|Solid bale:||38 lb (17.2 kg) carton|
|Premilled sheets*||50 lb. (22.7 kg) carton|
35 – 65 (50±10 typical)
|Storage stability||3 years when stored under dry and cool conditions|
TYPICAL COMPOUND PROPERTIES
|Hardness range||40 to 90 A|
|Tensile strength||Up to 5000+ psi, (35+ MPa)|
|Tear strength||Up to 400 lb/in (70 kN/m)|
|Heat aging 100º C (212º F)||Good|
|Hydrolysis resistance||Very Good|
|Oil & fuel resistance||Very Good|
|Low temperature||- 62º C brittle point|
TYPICAL END USES
|Printing rollers||Copier rollers|
|Drive Belts||Radar dome covers|
|Conveyor Belts||Footwear outsoles|
|Copier stops||Cable jackets|
|Aircraft fasteners||Dust covers|
Compounds based on Millathane E34 are typically vulcanized at temperatures of 150º - 175ºC, depending on the cure system used, with typical cure times of 5 to 20 minutes for compression molded lab sheets.
(See the Millathane Formulary for other compound examples)
|Process aid (Struktol WB222)||1.0|
|Cured Properties, press cure 12'/160ºC|
|Hardness, Shore A||62|
|100% Modulus, MPa||2.8|
|200% Modulus, MPa||6.4|
|300% Modulus, MPa||11.2|
|Tensile Strength, MPa||28.7|
|Elongation at break, %||525|
|Tear Die C, kN/m||38.3|
|Bashore Resilience, %||53|