Millathane® E40

Millathane E40 is a sulfur or peroxide curable polyether polyurethane rubber for the production of rollers, belts seals, gaskets, and other molded parts which require excellent abrasion resistance, low temperature performance, hydrolytic stability and high mechanical strength.

Processing

Millathane E40 is processed by techniques that are common to the rubber industry. Compounds can be mixed on an open mill or in an internal mixer. Millathane E40 has been designed not to crystallize at ambient temperatures, which allows mixing “right out of the box”. Due to the toughness of E40, a two-pass mix using an internal mixer is recommended. Very often a masterbatch can be mixed and followed by addition of curatives on a two-roll mill. Molded articles can be produced through compression, transfer or injection molding. Injection molding Millathane E40 provides very short cycle times, excellent flow and de-molding. Millathane E40 can be cured in steam autoclaves (protected from direct contact with the steam) and is suitable for large roller, hose or belting applications. Calendered sheets can be press-cured or rotational-cured.

Compounding

Compound design of Millathane E40 follows the typical pattern of formulating for oil resistant polymers. Reinforcing fillers like carbon black or fumed silica increase the mechanical strength. Sulfur cure is accomplished with the use of MBTS, MBT zinc stearate and Thanecure® ZM. A variety of dialkyl peroxides like dicumyl peroxide, t-butyl cumyl peroxide, 2, 5-dimethyl-2,5-di (t-butylperoxy) hexane etc. can be used as vulcanization chemicals. The use of co-agents like triallylcyanurate (TAC) results in a very high crosslinking density and improves the compression set. Adding various plasticizers and softeners, especially coumarone indene resins and TP-95 (DBEEA: Dibutoxyethoxyethyl adipate), improve processibility.

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
   *Bale wrap Strippable film (not meant to be incorporated into the compound)
Odor Faint, characteristic
Specific gravity 1.07
Mooney viscosity,
ML(1+4)/100°C)
35 – 55
Storage stability 3 years when stored under dry and cool conditions

TYPICAL COMPOUND PROPERTIES

Hardness range 45 to 90 A
Tensile strength Up to 4500+ psi, (31+ MPa)
Tear strength Up to 490 lb/in (86 kN/m)
Compression set Fair/Good
Heat aging Fair/Good (100ºC)
Ozone resistance Excellent
Hydrolysis resistance Very Good
Oil & fuel resistance Good/Very Good
Low temperature -48º C brittle point
Weathering Very good
Abrasion resistance Excellent
Resilience Up to 55%

Vulcanizates based on Millathane E40 offer a very good abrasion resistance, excellent low temperature properties, excellent hydrolytic stability, high mechanical strength and outstanding dynamic properties. Millathane E40 maintains its properties nearly unchanged over a wide range of temperatures and makes it a perfect choice for rollers seals, gaskets, CV-boots, dust covers, mounts and bearings for the automotive industry and for many other hydraulic or pneumatic applications. It is particularly suited for production of injection molded rollers for office machines due to its ability to bond to metal shafts.

Vulcanization Conditions

Compounds based on Millathane E40 can be vulcanized at temperatures between 140 - 165ºC, depending on the cure system and the thickness of the part.

Formulation Examples

(See the Millathane Formulary for other compound examples)

Millathane E40 100.0
Zinc Stearic 0.5
N330 Black 25.0
DBEEA (TP-95) 2.0
Struktol WB222 1.0
MBTS 4.0
MBT 2.0
Thanecure® ZM 1.0
Sulfur 1.5
Total 137.0
Press Cure 7'/160ºC
Durometer A 70
100% Modulus, psi (MPa) 455 (3.1)
300% Modulus, psi (MPa) 1670 (11.5)
Tensile Strength, psi (MPa) 3680 (25).4
Elongation, % 485
Tear Die C, lb/in (kN/m) 237 (41.5)
Tear Die B, lb/in (kN/m) 392 (68.6)
Resilience, % 43
DIN Abrasion, mm³ loss 66
Compression set, 22 hr/70ºC, % 37