A High Performance Millable Polyurethane Rubber
(Formerly known as Vibrathane 5004)
Millathane 5004 is a peroxide curable polyester millable urethane rubber. It has excellent processing characteristics and can be injection molded easily. In addition to excellent abrasion resistance, Millathane 5004 has the highest stress strain values of all peroxide cured polyurethanes. The cured stock has excellent tear strength, excellent low temperature flexibility and resistance to oxygen, ozone, fuels and oils.
Millathane 5004 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 5004 compounds typically contain reinforcing fillers to 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 5004. Millathane 5004 is peroxide-curable only. Typical peroxides used include DiCup 40C and Varox DBPH-50. Carbodiimides can be added at 1-5 parts for improved hydrolysis resistance. A compound with 5 parts of polymeric carbodiimide (Millstab™ P) had excellent retention of properties after 1 year water exposure.
Vulcanizates based on Millathane 5004 can be produced in hardnesses ranging from 40 to 95 Shore A, and offer very good abrasion resistance, excellent oil resistance, good low temperature properties and good gas permeability.
Typical Polymer Properties
|Chemical type||Polyester polyurethane|
|Color||White to off-white|
|Physical form||Solid chunks or milled sheets|
|Solid chunks:||50 lb. (22.7 kg) carton|
|Premilled sheets**||50 lb. (22.7 kg) carton|
|*Bale wrap||Strippable film (not meant to be incorporated
into the compound)
|50 – 70|
|Storage stability||2 years when stored under dry and cool conditions|
TYPICAL COMPOUND PROPERTIES
|Hardness range||40 – 95 A|
|Tensile strength||Up to 5000 psi, (35 MPa)|
|Tear strength||Up to 450 lb/in (78 kN/m)|
|Hydrolysis resistance||Good/Very good (with hydrolysis stabilizers)|
|Oil & fuel resistance||Very Good/Excellent|
|Resilience||30 - 60%|
Compounds based on Millathane 5004 are vulcanized at temperatures of 150º - 175ºC, depending on the peroxide used, with typical cure times of 5 to 20 minutes for compression molded lab sheets. Injection and transfer molding are also being used commercially with Millathane 5004 compounds.
(See the Millathane Formulary for other compound examples)
|Polymeric carbodiimide (Millstab™ P)||2.0|
|Cured Properties, press cure 16'/160ºC|
|Hardness, Shore A||70|
|TSE100*, psi (MPa)||475||(3.3)|
|TSE200*, psi (MPa)||1090||(7.5)|
|TSE300*, psi (MPa)||1950||(13.4)|
|Tensile Strength, psi (MPa)||4100||(28.3)|
|Elongation at break, %||525|
|Tear Die C, lb/in (kN/m)||314||(55)|
*TSExxx=Tensile Stress at xxx% Elongation
|Bashore resilience, %||46|
|DIN Abrasion, mm³ loss||57|
|Compression set, 22 hr/70ºC, %||10|
|Compression set, 22 hr/100ºC, %||36|
|Compression set, 22 hr/125ºC, %||53|
|Oven Aging, 70 Hr/100ºC|
|Tensile strength, % change||+3|
|Elongation, % change||-5|
|IRM 903 Oil Aging, 70 Hr/100ºC|
|Tensile strength, % change||-30|
|Elongation, % change||-37|
|Volume change, %||2|
Vibrathane is a registered trademark of Chemtura Corp.