Abrasion Resistance
Urethane will outperform rubber, plastic or metal by a margin of
5 to one in severe abrasion and
wear applications.
Adhesion
Urethane prepolymer formulations can be adhesively
bonded to most metals or virtually any other material, whether rigid
or flexible. Cast bonding systems can be designed to produce bonds
that are often stronger than the urethane itself.
Chemical Resistance
Urethane prepolymer formulations have excellent resistance
to most solvents, chemicals, aliphatic based oils, and greases.
Coloring
Color variation available upon request.
Dimensional Stability
Urethane prepolymer formulations
have excellent dimensional stability over a broad range of temperatures
and pressures. Urethane’s also have excellent elastomeric
memory. They can be stretched (even at high hardness) to substantial
elongations and return to their original dimensions.
Electrical Properties
Urethane prepolymer formulations offer a combination of electrical
properties, such as dielectric strength, dielectric constant, resistivity
and power factor. Urethane is an excellent insulating material.
Depending upon the formulation, its volume of resistivity is in
the range of 1010 to 1011 ohm-cm. With additives, urethane can also
be formulated to be electrically conductive.
Environmental Resistance
Urethane is substantially inert in the presence of ozone and oxygen.
It is more resistant than natural or synthetic rubber to sunlight
and general weather conditions.
Flex Properties
Urethane prepolymer formulations offer extremely high flex-life
and can be expected to outlast other elastomeric materials where
repeated flexing is an important requirement.
Friction Coefficients
Urethane can be formulated to offer various coefficients
of friction that will remain permanently in your compound. This
is usually not possible with other elastomers which may continue
to cure, harden, or soften over their usual life, with resultant
changes in the coefficient of friction.
Hardness
Urethane prepolymers can be formulated to cover a wide range
of hardness, from 20 Shore A durometer
(the hardness of a rubber band) to 75 Shore D durometer (the hardness
of bone).
Hydrolytic Stability
Polyether based urethane prepolymer formulations have superior hydrolytic
stability. They absorb practically no water (barely 0.3% to 1% by
weight) and are suitable for applications requiring immersion.
Impact Resistance
With even the hardest urethanes, you can achieve significantly better
impact resistance than plastics
and composites. While conventional plastic materials can become
brittle as they become harder, urethane retains elasticity and strength
over the complete range of hardness.
Load-Bearing Capacity
Compared to other elastomers of equal hardness, urethane prepolymer
formulations have a greater load-bearing capacity.
Machinability
Harder formulations can be drilled, tapped and machined like metal;
softer materials can be ground.
Resilience
Urethane prepolymers can be custom formulated to give hard polyurethanes
similar resiliency as much softer materials, making urethane an
excellent material for shock/vibration absorption.
Sound Dampening Properties
Urethane has superior sound dampening properties. Hard durometers
are being used in gears and other applications where sound reduction
is desired. Soft durometers are being used to replace rubber for
improved sound/vibration dampening.
Tear Strength
Urethane ranges between 250-1000 lbs/linear inch, which are far
superior to rubbers in all applications. As a result, urethane is
often used as drive belts, seals, diaphragms, roll covers, cutting
pads, gaskets, and chute liners.
Temperature Resistance
Urethane prepolymers can be formulated to operate dependably at
250°F and intermittently at 300°F. Urethane is not recommended
in hot water over 175°F. At low temperatures urethane will retain
a degree of elastomeric properties at -80°F. A gradual stiffening
will occur at 0°F but will not become pronounced until much
lower temperatures are obtained.
Tensile Strength
Urethane can be formulated with tensile
strengths to 8,000 psi while maintaining elastic characteristics.
Tooling Cost
As a liquid cast material, tooling costs are very low—significantly
less than making metal molds.
Toughness
Urethane is non-brittle even at higher hardness and resists fracture
during shock or impact loading.
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