Types

 

 How will your O-rings perform when under chemical attack?

vitonWhenever you purchase O-rings that require resistance to hydrocarbon fluids (fuel and engine oil), especially ULSD and BioDiesel (methyl Oleate), make sure they are Viton® fluroelastomers.
Independent studies have shown that Buna, Buna-N (Nitrile), Natural Rubber and Neoprene are rated from "Less than Satisfactory" to "Not Recommended" when used for today's diesel fuels due to elastomer swell and rapid material oxidation. 

Viton® is a registered trademark of Dupont Performance Elastomers


Selecting the Type of Viton® That Is Best For You

There are many types of Viton® to meet specific end-use and processing needs. This table shows how different types of Viton® compare in chemical resistance and mechanical properties.

Selecting the type that best meets your needs is important, but is not complicated. The general purpose types differ from the specialty types primarily in chemical resistance. In the specialty family, the choice is among four types that are tailored for superior fluid resistance, low-temperature performance or combinations of these properties but are only available in large quantities and high costs.

Relative Chemical Compatibility and Mechanical Properties of Viton® Fluoroelastomers
Viton®
General Use
Family Types
Viton®
Specialty
Family Types
Chemical Environment
A
B
F
GBL
GF
GLT
GFLT
ETP
Automotive and aviation fuels
1
1
1
1
1
1
1
1
Automotive fuels oxygenated with MEOH, ETOH, MTBE, etc.
4
2
1
2
1
4
1
1
ULS Diesel Fuels
2
1
1
1
1
1
1
1
Engine lubricating oil, SE and SF
2
1
1
1
1
1
1
1
Engine lubricating oil, SG and SH
3
2
2
1
1
2
1
1
Aliphatic hydrocarbon process fluids, chemicals
1
1
1
1
1
1
1
1
Aromatic hydrocarbon process fluids, chemicals
2
2
1
1
1
2
1
1
Aqueous fluids, steam mineral acids
3
2
2
1
1
1
1
1
Strong base, high pH, caustic, aminos
4
4
4
4
4
4
4
1-2
Low molecular weight carbonyls - 100% concentration (MTBB, MBK, MIBK, etc.)
4
4
4
4
4
4
4
1-2
Compression Set and Low-Temperature Performance
Resistance to compression set
1
2
2
2
3
2
2
2
Low-temperature flexibility
2
2
3
2
3
1
1
2

Key: 1 = Excellent 2 = Fair to Good 3 = Poor 4 = Not Recommended

Viton® is a registered trademark of DuPont Performance Elastomers

 

Elastomers and BioDiesel

 

How do other compounds hold up to biodiesel? You may want to read this study from the National BioDiesel Board before you put much faith in those Buna-N o-rings. Material Compatibility Study