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Millathane® 66

A High Quality Millable Polyester Polyurethane Elastomer

See NEW publication TIPS V5-3 on Millathane 66 formulations for high heat resistance in the TIPs section (top right)! Millathane 66 is a peroxide curable urethane rubber for the production of oil, fuel and chemical resistant parts which require excellent low and high temperature performance and high mechanical strength. Compounds of Millathane 66 have excellent abrasion resistance. Millathane 66 Premilled contains 1.5 phr of a polycarbodiimide (Millstab™ P) as a stabilizer for improved hydrolysis resistance and heat aging properties.

For more information about Millathane® and Thanecure® products, please contact: Lynn Zylka at (727) 540-1358 or contact Lynn here.


Product Description

Chemical composition: Millable polyurethane based upon ester/MDI
Specific gravity: Approximately 1.19g/cc
Appearance: Clear to tan colored bales or, for pre-milled, white to tan colored milled sheets
Package: 45lbs/50lbs per box(Virgin/Premilled)
Storage stability 2 years when stored under dry and cool conditions

 

Processing

Millathane 66 is processed by techniques which are common to the rubber industry. Compounds can be mixed on an open mill or in an internal mixer. Very often, compounds can be mixed in one step including the vulcanization chemicals. Molded articles can be produced via compression, transfer or injection molding. In injection molding, Millathane 66 provides very short cycle times, excellent flow and de-molding and shows hardly any mold fouling. Due to the peroxide vulcanization and its chemical base, Millathane 66 cannot be cured in open steam and, for hose applications, can only be used as inner liners. Calendered sheets can be press or rotocured.

 

Compounding

Compound design of Millathane 66 follows the typical pattern of formulating peroxide-crosslinked rubber compounds: active fillers like carbon black or fumed silica increase the mechanical strength, a variety of dialkyl peroxides like dicumyl peroxide, t-butyl cumyl peroxide,2,5-dimethyl-2,5-di (t-butylperoxy) hexane {DBPH) etc. can be used as vulcanization chemicals (See TIPS V5-1 for a DBPH peroxide study in Millathane 66). The use of co-agents like methacrylates and TAC (triallyl cyanurate) results in a very high crosslinking density and improves the compression set. Millathane 66 Premilled contains 1.5 phr of an aromatic polycarbodiimide (Millstab™ P) for improved hydrolysis resistance and heat aging properties. In a few applications where severe water or humidity exposure is encountered, a total level of 2-5 phr Millstab™ P might be desirable.

 

Properties

Vulcanizates based on Millathane 66 offer very good heat resistance, excellent low temperature properties, low compression set, high mechanical strength and outstanding dynamic properties with high chemical resistance and low gas permeability. Compounds based upon Millathane 66 have very good abrasion resistance. Millathane 66 maintains its properties nearly unchanged over a wide range of temperatures which makes it a perfect choice for seals, gaskets, o-rings, membranes, CV-boots, dust covers, mounts and bearings for the automotive industry and for many other hydraulic or pneumatic applications. Millathane 66 is also widely used in the production of rollers and flippers for office machines and drive belts for audio and video equipment.

 

Vulcanization Conditions

Compounds based on Millathane 66 are vulcanized at temperatures of 140 - 180º C, depending on the peroxide, section of the part, etc. Injection molded parts with a wall thickness of less than 2mm can be vulcanized in approximately one minute at 170 - 180º C mold temperature.

 

Formulation Example

(See the Millathane Formulary for other compound examples)
Millathane 66100.0
Stearic Acid0.25
Aflux 542.0
N 550 Black20 .0
Varox DBPH-505.0
TAC0.5
Press Cure 20'/160°C
Hardness, Shore A66
100% Modulus, MPa3.8 (550 psi)
300% Modulus, MPa27.5 (3990 psi)
Tensile Strength, MPa33.1 (4800 psi)
Elongation at break, %350
Tear Die C, kN/m60 (343 lb/in)
Compression Set, %, 22h @ 100° C11
Bashore Resilience, %35
Brittle Point, °C-56

TIPs

Formulary

Millathane® 66 Compounds
Hardness, Shore A ID/Link Description
46 541

Non-Black – General Purpose

63 1668 Black, ASTM D2000 M*BG628 A14 B14 EO34
65 537

Black, semi-conductive

70 519

Yellow Molding Compound

80 1578

Black, Molding Compound

88 TIPS V5-3 Black Molding Compound, High Heat Resistance
94 1704

Non-Black Molding Compound