Natural, SBR and  Neoprene

May-Lin Silicone Products, Inc.
PO Box 335 • 955 Wooster Road West Barberton, Ohio 44203
Phone: 330-825-9019 • Fax: 330-825-6153

Natural Rubber is nature's contribution to the elastomer field. The bulk of natural rubber used for engineering applications is plantation rubber, smoked sheet and pale crepe. Natural polyisoprene offers an excellent balance of properties, resulting in outstanding performance in many demanding mechanical applications. Quality compounds of natural rubber meet a wide range of stiffness requirements.
The major advantages of natural rubber are high resilience, high tensile and tear properties and excellent resistance to cold flow. When compounded with carbon black, NR exhibits superb abrasion or wear resistance. The polymer has low
permanent set characteristics, good flexing qualities at low temperatures and can be bonded to a wide range of materials.
Natural rubber is widely used where many types of acids and bases, except those types that are highly oxidizing, are present.
When exposed to petroleum derivatives, ozone, sunlight and oxygen, natural rubber and its heat aging properties are inferior to many of today's synthetics,

SBR, a synthetic copolymer composed of styrene and butadiene, is used more often than any of the other
synthetics produced today. Many types of SBR rubber are available in oil extended and black masterbatch forms to serve specific applications.
Certain types of SBR offer improved wear resistance in tire treads while others provide better low temperature flexibility. SBR has similar residence to solvents and chemicals as natural rubber, and it can be successfully bonded to a wide range of materials.
When exposed to petroleum derivatives, the performance of this rubber is inferior to many other synthetics, and in some applications, the products heat aging characteristics are slightly deficient.

Neoprene is a polymer chloroprene and is available in many varieties including nonsulfur "W" and the more common sulfur modified"GN" types. Neoprene is known for its resistance to oil, gasoline, sunlight, ozone and oxidation: however, there are other polymers that have better resistance to these same elements. CR's most important advantage is its ability to combine these properties moderately into one all-purpose polymer.
Certain compounds of neoprene are flame resist and will not support combustion.
Resistance to corrosive action of chemicals is good, but is inferior to butyl. Hypalon, EP and florocarbons. Neoprene G types exhibit better resilience, tensile strength, tear resistance and dynamic properties: whereas neoprene W types are better for abrasion resistance and compression set properties.