Millathane® E34

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.

PROCESSING

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.

COMPOUNDING

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
Packaging
   Solid bale: 38 lb (17.2 kg) carton
   Premilled sheets* 50 lb. (22.7 kg) carton
Odor Faint, characteristic
Specific gravity 1.04
Mooney viscosity,
ML(1+4)/100°C)
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)
Compression set Good
Heat aging 100º C (212º F) Good
Ozone resistance Excellent
Hydrolysis resistance Very Good
Oil & fuel resistance Very Good
Low temperature - 62º C brittle point
Weathering Very good
Abrasion resistance Excellent
Resilience 40-60%

TYPICAL END USES

Printing rollers Copier rollers
Drive Belts Radar dome covers
Conveyor Belts Footwear outsoles
Copier stops Cable jackets
Aircraft fasteners Dust covers

VULCANIZATION CONDITIONS

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.

FORMULATION EXAMPLE

(See the Millathane Formulary for other compound examples)

Millathane E34 100.0
Zinc Stearate 0.5
N330 Black 25.0
DBEEA (TP-95) 5.0
Process aid (Struktol WB222) 1.0
MBTS 4.0
MBT 2.0
Thanecure® ZM 1.0
Sulfur 1.5
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