Elastomer Comparison Guide

Rubber is classified by many physical properties but generally falls under two promary classifications: Dense or Sponge rubber. This section outlines properties that are necessary to consider when designing a seal or gasket product.

Choosing the right sponge product is important in proper seal and gasket design. Engineers must consider force in pounds per square inch required for proper closing, how the seal responds to being compressed over time or being compressed and released and even to what elements will the product be exposed. The below technical information will serve as a guide to comparing materials with their physical properties.

Comparison Guide to Elastomer Properties

Key: E=Excellent, VG=Very Good, G=Good, F=Fair, P=Poor

Natural Rubber
SBR
EPDM
Neoprene
Nitrile
Silicone
FKM
Chemical Name
 Polysoprene Styrene Butadiene Ethylene Propylene Chloroprene Acrylonitrile Butadiene Polysiloxane Fluorinated Hydrocarbon
Physical Properties
Specific Gravity
 0.93 0.94 0.86 1.23 1.00 0.95 to 1.20 1.40 to 1.95
Durometer, Range
 30-100 40-100 30-90 40-95 30-90 25-90 55-90
Tensile Strength
 E F-G VG VG VG F-G VG
Elongation
 VG-E G G G G VG-E F-G
Compression Set
 G G G F-G G G-E G-E
Heat Resistance
 F F-G VG-E F-G G E E
Resilience or Rebound
 E F-G G VG F-G G F
Impact Resistance
 E E G G F P-G E
Abrasion Resistance
 E G-E G-E G-E G-E P-F F-G
Tear Resistance
 E F F-G F-G F-G P-F F
Cut Growth
 E G G G G P-F P-F
Flame Resistance
 P P P G P F-G VG-E
Impermeability, Gas
 F F F-G F-G G F-G E
Weathering Resistance
 P-F F E VG F-G E E
Low Temperature Limit
 -10° to -50°F 0° to -50°F -20° to -60°F -10° to -50°F -10° to -30°F -65° to -100°F +10° to -40°F
High Temperature Limit
 170° to 225°F 170° to 225°F 300° to 350°F 225° 250° 400° to 550°F 400° to 450°F
Chemical Resistance Properties
Acid
 F-G F-G G G G F G
Alcohols
 G G F-G VG F-G G F-E
Aliphatic Hydrocarbon Solvents
 P P P G E P-F E
Alkali
 F F VG E VG P F-G
Animal & Vegetable Oils
 F F G G VG G E
Aromatic Hydrocarbon Solvents
 P P P P-F F-G P-F E
Oil & Gasoline
 P P P F-G G-E P-F E
Oxygenated Solvents
 G G vG P-F P F P
Water
 E G-E E G G-E G-E G

The range of properties that can be developed for any given polymer is limited by the material itself, and will vary within that range with compound formulation. All properties in a particular class are not found in a single compound. However, it is often possible to raise or lower some ratings to acceptable levels through creative compounding.