A brief description of Polyurethanes
POLYURETHANES are a class of synthetic elastomers with programmable properties. Polyurethanes are widely used in industry as effective substitutes for rubber — to manufacture parts for use in aggressive media and under large fluctuating loads and high temperatures. The operating temperature for most polyurethanes is between -60° and +80° C. They can tolerate a short-term increase in operating temperature to 120° C for up to 24 hours.
Polyurethanes are not very susceptible to aging, and they exhibit a low glass transition temperature and excellent environmental stability. Polyurethanes are resistant to abrasion, most organic solvents, ozone, ultraviolet rays and sea water.
As mentioned above, “polyurethane” is the name given to an entire class of synthetic substances. The undisputed advantage of polyurethanes is that their hardness (elasticity) can be programmed, meaning that it can vary greatly, depending on the ratio of the components used to manufacture a given polyurethane. Polyurethanes may consist of one, two or three components. The quality of the various polyurethanes, their properties, their application and thus their cost vary considerably.
The products we manufacture come in several degrees of hardness. Therefore, the polyurethane we use has a variety of properties, depending on its hardness, but its properties always surpass those of rubber.
COMPARISON of physical and mechanical properties of rubber and polyurethane
|Shore hardness (A scale)||65-75||40-98*|
|Tensile modulus 100%||12||29|
|Resiliency (elasticity) %||30||40|
|Breaking strength (kg / cm2)||115||312|
|Elongation at break (%)||300||540|
|Tear strength (method C), N / mm||20||58|
|Frost resistance coefficient for elastic recovery |
after compression, at -50 ° С
|Abrasion resistance (Scraper H22)||2||10|