Wide Hardness Range
Polyurethane offer a very wide hardness range in which items can be produced. They range from 35° Shore A to 80° Shore D. Please refer the following table:
Hardness Guide |
Hardness |
Shore Scale |
Description |
35 |
A |
Rubber Band |
50 |
A |
Inner Tubes |
60 |
A |
PVC Hose |
70 |
A |
Car Tyre Treads |
95 |
A |
Fork Lift Truck Tyre |
60 |
D |
Polyethylene Rigid Plastic |
80 |
D |
Nylon Rigid Plastic |
Abrasion Resistance
In applications where severe wear is a problem, polyurethane offer outstanding durability when compared with rubber, plastics or even metal. In many applications the unusual combination of properties has made it possible to design and fabricate products from polyurethane using less material than has been possible with other elastomers.
High Strength Properties
Working in rubber hardness, polyurethane have greater compression strength, tensile strength and tear strength than rubber. Working in plastic hardness, polyurethane have greater impact strength and bending strength.
Terrific Mechanical Properties
Polyurethane do well in common mechanical process, such as lathing, milling, grinding, drilling. Such great toughness combined with the many other outstanding properties associated with the high hardness polyurethanes, leads to many applications in engineering.
Good Resilience
Formulations are available in a very wide range of resilience. For very shock absorbing uses, low rebound compounds are usually used i.e. rebound value of 10-40%. For high frequency vibrations or where quick recovery is required, compounds in the 40-65% rebound value are used.
Low Temperature Resistance
Many polyurethane remain flexible at very low temperatures and possess outstanding resistance to thermal shock. The low temperature resistance of polyurethanes has led to many applications in Arctic conditions.
Water Resistance
Depending on type, polyurethane are very resistant to the swelling and deteriorating effects of water immersion and have excellent long-term stability in water up to 50°C. Continuous use in hot water over 80°C is not recommended.
Oxygen and Ozone Resistance
Products made from polyurethanes are highly resistant to degradation by atmospheric oxygen and ozone. This makes polyurethanes highly successful when employed around electrical equipment, without hardening and cracking often experienced with conventional elastomers and indeed many plastics.
Oil Grease and Chemical Resistance
Whilst many rubbers and plastics have excellent resistance to one or more specific solvents, oils or chemicals, the wide resistance of polyurethanes to chemical attack means that they can be used in a multitude of environments with the exception of strong solvents.
Radiation Resistance
Polyurethane are considered to have the best resistance to gamma ray radiation. They retain a high proportion of their original flexibility and toughness whilst exposed to gamma radiation.
Flame Resistance and Anti Static Property
Special compounds containing flame-retardants and antistatic agent can be formulated to meet several non-burning and anti static specifications. These two properties are especially suitable for mining industry.