How it is Made

This substance is categorized as a polymer — a molecule that consists of a series of repeating smaller units called monomers — based on its chemical structure. It is manufactured by combining two types of compounds, a diisocyanate and a diol, which are monomers, through a chemical reaction. This makes a basic material whose variations can be stretched, smashed or scratched and will remain fairly indestructible. Depending on the different diisocyanates and diol or polyol constituents, the resulting polyurethane might be in the form of a liquid, foam or solid. Each form has its own advantages and limitations.

Elastomers

Some polyurethane is categorized as an elastomer. It has elastic properties while maintaining some rigidity, which is beneficial for items such as the wheels of a dolly, which must absorb shock without compressing too much. Polyurethane can be extremely flexible when used as a foam insulator in construction or a foam cushion in upholstery. It can be deformed over and over and still maintain its original shape. In other words, it has what is called structural memory.

Thermoplastics

Other polyurethane is a thermoplastic that resembles other kinds of plastic, metal or fiberglass. Thermoplastics are rigid and smooth, with a sealed surface that is impermeable to water. These are used when strength and durability are important, such as in seats at an airport terminal or packaging crates on a truck. Some polymer thermoplastics are difficult to recycle, but they can be reused.

Many Other Uses

Polyurethane can be found in every room of the house and in practically every building. Since this material became popular during World War II, the polymer has protected, reinvented, joined or transported countless items. It seals surfaces such as wood, metal and paint to protect them from rot, corrosion or fading. As an adhesive, polyurethane resists moisture and heat, so it is ideal for use in the sun or underwater. It also insulateswalls, temperature-controlled vehicles and consumer coolers


ADVANTAGES TO POLYURETHANE


Abrasion resistant
Parts made of polyurethane will often outwear other materials by a margin of 5 to 50/one when severe abrasion is a factor. It has been proven to be vastly superior to rubber plastics and metal in many applications.


Oil and solvent resistant
Polyurethane has excellent resistance to oils, solvents, fats, greases and gasoline.

Load bearing capacity
Polyurethane has a higher load-bearing capacity than any conventional rubber. Because of this characteristic, it is an ideal material for load wheels, heavy duty couplings, metal-forming pads, shock pads, expansion joints and machine mounts.

Tear resistant
Tear-strength ranges between 500-100 Ibs./linear inch, which is far superior to rubbers. As a result, urethane is often used as drive belts, diaphragms, roll covers, cutting pads, gaskets and chute liners.

Weather resistant
Polyurethane has outstanding resistance to oxygen, ozone, sunlight and general weather conditions.

Excellent noise abatement properties
The hard urethanes are now being used as gears in products where engineers desire sound reduction. The soft urethanes are used to replace rubbers for improved sound/vibration dampening.

Flex-Life
Most formulations offer extremely high flex-life and can be expected to outlast other elastomer materials where this feature is an important requirement. Dust boots, bellows, diaphragms, belts, couplings and similar products are made from urethane for this reason.

Electrical properties
Polyurethane has excellent electrical insulating properties and is used successfully in many moulded wire and cable harness assemblies.

Heat and cold resistant
Continuous use above 225°F is not recommended nor is urethane recommended in hot water over 175°F. At low temperatures, polyurethane will remain flexible down to -90°F. A gradual stiffening will occur at 0°F, but will not become pronounced until much lower temperatures are obtained.

APPLICATIONS
Belts
Metal forming pads
Wear strips
Bumpers
Gears
Bellows
Machinery mounts
Cutting Surfaces
Sound-dampening pads
Chute and hopper liners
Prototype machined parts
Gaskets
Seals
Rollers
Roller covers
Sandblast curtains
Diaphragms