Multiple components make up the rubber formula or recipe. The biggest component and determining factor is the base polymer. The base polymer might be Nitrile, Neoprene, EPDM or Natural Rubber for example. This determines many of the formula’s physical properties and is also the biggest cost driver within the formula. Continue reading
NATURAL RUBBER (NR) Natural Polyisoprene
Advantages: Outstanding resilience; high tensile strength; superior resistance to tear and abrasion; excellent rebound elasticity; good flexibility at low temperatures; excellent adhesion to fabric and metals.
Limitations: Poor resistance to heat, ozone, and sunlight; very little resistance to oil, gasoline, and hydrocarbon solvents. Continue reading
Written By: Tony Lukas, Chemist Molded Dimensions Inc
Polyurethane suppliers and processors are continually looking to develop new materials and applications to take advantage of the unique properties of urethane. One advantage that urethane has over rubber is much higher abrasion resistance. This has historically been particularly true as the hardness reaches Shore 80A and above. Although materials of softer hardness have long been available, the physical properties and abrasion resistance has not been a good as rubber in the 50A-70A range. New developments are allowing for both polyether and polyester based materials that are great improvements over currently available urethanes and even better than natural rubber and SBR. Typical applications for these types of materials would be in systems with heavy flow of particulate containing liquids or slurries. Continue reading
There are two types of abrasion – sliding and impingement. Sliding is the passing of an adjacent surface across the rubber surface. Impingement is wearing of the rubber exemplified by sand particles hitting the surface. Most wear in actual service occurs as a combination of both sliding and impingement.
When sliding, localized friction forces can impose high energy levels on the rubber. Abrasion and wear takes place when the rubber cannot withstand these forces.