Limitations Of PU Products

Limitations Of PU Products

The useful temperature range for polyurethanes is from around 30 degrees C to an upper limit of 70 to 80 degrees C. Above this upper limit ageubg processes set in and the operating life is curtailed.

In Most Dynamic applications we recommend staying at temperatures below 160°F (70°C ). The normal, high property working range is -40°F to 160 °F(-40°C to 70°C). At 160°F (70°C) the properties of the elastomer begin to show a decline. The bond between urethane and metal weakens considerably above 160°F (70°C).

Polyurethane rubber should not be used un dynamic applications above 200°F (93°C). When testedat 200°F (93°C) their properties are only half of those measured at 75°F (25°C) . They heat age well however, and the effect of high temperatures up to 250°F (120°C) for weeks on physical properties is almost completely reversible when tested again at 75°F(25°C) .

Intermittent exposures to higher temperatures upto 100 degrees C or 110 degrees C is acceptable but not recommended.

Polyurethanes have limited resistance to water. Continuous immersion in water above 50 degrees C can result in hydraulic breakdown and for this reason a maximum upper limit of around 70 degrees C under these conditions should apply. Again all aspects of the application must be considered and where instances of high wear and tear are involved, polyurethanes give a longer life at 60 degrees C in water than do other elastomers of better hydrolic stability.

Urethane exhibit high hysteresis and low thermal conductivity. They do not dissipate heat built up by a dynamic action quickly. Avoiding heat build-up in an elastmeric part is a paramount consideration in design. In practice, this is usually done by controlling the amplitude of the deflection.

Long term exposure to hot, humid environments should be avoided. Some urethanes are much more resistant than others to this environment.

Certain chemicals such as concentrated acids and polar solvents attack urethanes, and urethanes should not be put into continuous service in these environments.

Member Testimonials

ONGC – Oil and Natural Gas Corporation Limited

"ONGC - Oil and Natural Gas Corporation Limited" - Our complex drilling application where Shaft was eccentric and application was robust & muddy. Replacement was never easy. Mech Spares designed Oil seals resolved difficulty. This gave a complete joy to my maintenance team.
2014-06-08T07:48:57+00:00
“ONGC – Oil and Natural Gas Corporation Limited” – Our complex drilling application where Shaft was eccentric and application was robust & muddy. Replacement was never easy. Mech Spares designed Oil seals resolved difficulty. This gave a complete joy to my maintenance team.

Kuwait National Petroleum Company

"Mr Mohammed Al Duaigy" of (Kuwait National Petroleum Company) : We tried several diaphragms from renown worldwide Rubber manufacturing companies. We found Mech Spares technical know how and product to be of great durability and lasted 3 times more then anticipated. They have accurate understanding of there products.
2014-06-08T07:49:23+00:00
“Mr Mohammed Al Duaigy” of (Kuwait National Petroleum Company) : We tried several diaphragms from renown worldwide Rubber manufacturing companies. We found Mech Spares technical know how and product to be of great durability and lasted 3 times more then anticipated. They have accurate understanding of there products.

McCafferty BM Design Ltd, KENT United Kingdom

"McCafferty BM Design Ltd, KENT United Kingdom" - Most of the O rings manufacturing company suggested to use larger diameter and expensive elastomers. We learnt with Mech Spares that elastomer being weaker compare to metal and alloys and needs appropriate back up for high pressure or high vacuum applications. Further not necessary the most expensive elastomer is the best for all applications. We trust Mr Nilesh chodhari completely for all our O rings designing applications.
2014-06-08T07:50:26+00:00
“McCafferty BM Design Ltd, KENT United Kingdom” – Most of the O rings manufacturing company suggested to use larger diameter and expensive elastomers. We learnt with Mech Spares that elastomer being weaker compare to metal and alloys and needs appropriate back up for high pressure or high vacuum applications. Further not necessary the most expensive View Full →

Bhabha Atomic Research Centre ( BARC )

"Dr. A. Singh" of BARC: The electric Insulation mat manufactured by MECH SPARES as per IS 15624 tested at ERTL and found to withstand 40 Kv and still didn't tear. We have been using since 5 years and still didn't generate any fatigue. They arranged bulk delivery in short period.
2014-06-08T07:16:20+00:00
“Dr. A. Singh” of BARC: The electric Insulation mat manufactured by MECH SPARES as per IS 15624 tested at ERTL and found to withstand 40 Kv and still didn’t tear. We have been using since 5 years and still didn’t generate any fatigue. They arranged bulk delivery in short period.

Tata Steel

"Tata Steel" - One of our old machines started making loud noise and disturbed the entire village. We were compelled to stop the machines which lead to huge production loss. With the help of Mech Spares designed bellows in two part we could retain the lubrication and eliminate the noise.
2014-06-08T07:17:16+00:00
“Tata Steel” – One of our old machines started making loud noise and disturbed the entire village. We were compelled to stop the machines which lead to huge production loss. With the help of Mech Spares designed bellows in two part we could retain the lubrication and eliminate the noise.
View O Ring Reference Chart