Choosing what Millathane® millable polyurethane grade you need, but not sure where to begin?  Let’s start by first discussing what Millathane is and how it is manufactured. Millathane is a reaction product of a diisocyanate with a polyol and a chain extender, and it is processed using standard rubber processing equipment. It can also be crosslinked using sulfur or peroxide cure systems. 

From there, Millathane is broken down further into TWO main categories or Grades, polyether-based or polyester-based. These millable polyurethane grades are determined by the type of polyol used. While both Polyether and Polyester Grades offer excellent abrasion resistance and strength properties, there are very distinct differences between the two. Polyether grades offer better resistance to water and humidity. Polyester grades offer better resistance to oil, fuel, and solvents.    

Choosing the best Millathane grade comes down to which compound properties are most important for your application. Is water or humidity resistance critical? A polyether grade is a better choice.  Are oil, solvent, and fuel resistance more important? Polyester is a better choice. Different Millathane grades within these two categories offer other unique properties, too. There are thousands of Millathane formulas, but the below list should guide you to the proper grade and get you on your way!

Polyester: Best Choice for Heat, Oil, and Compression Set Resistance

Millathane 66R
Oil, fuel, and chemical resistance, excellent low and high temp performance, mechanical strength
Uses: Seals, gaskets, O-rings, membranes, CV-boots, dust covers, bearings for the automotive industry, hydraulic or pneumatic applications, drive belts, rollers

Millathane 76
Excellent dampening and vibration control, excellent oil and fuel resistance, abrasion resistance
Uses: Automotive parts, O-rings, seals, gaskets, seals, diaphragms, bushings, test pads, suction cups, rubber-covered rollers, and solid tires

Millathane 5004
Low-temp flexibility, excellent oil, fuel and solvent resistance, high strength and abrasion resistance, resistance to gas permeability
Uses: Seals, gaskets, O-rings, suction cups, rollers, diaphragms, molded electrical parts, dust covers

Polyether: Best Choice for Water and Hydrolysis Resistance

Millathane 26
Meets FDA regulations for wet and dry food contact (21CFR 177.2600), hydrolysis resistance, good strength
Uses: Belting, rollers, seals, gaskets, lining, curtains, hoses

Millathane E40
Excellent abrasion resistance, low-temp performance, hydrolytic stability
Uses: Rollers, belts, seals, gaskets, military, aeronautical

Millathane 55
Low viscosity, high hardness, excellent water, abrasion, ozone resistance, hydrolytic stability
Uses: Rollers, belting, industrial wheels, seals, footwear

Millathane 97
Excellent wear properties, excellent transparency, high coefficient of friction, very good UV stability
Uses: Shoe soles, roll covers, or where transparent, brightly colored, or decorative products are desired

Millathane CM
Abrasion and water resistance, excellent low-temperature properties
Uses: Rollers, military, aircraft, belts, bushings, seals, rollers

Millathane E34
Outstanding hydrolytic stability, water and abrasion resistance, low-temp flexibility
Uses: Rollers, seals, footwear, belting, gaskets, industrial wheels

Download our Millathane Polymer Selector Guide for even more details including density and Mooney viscosity levels of the different grades presented above. You can find even more information including specific Millathane formulas and safety data on our website.