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Appendix III
Appendix III
Chemical-Resistant Properties and Hardness Ranges of Both Natural and Synthetic Rubbers
Property
Natural Rubber
Butyl Rubber
EPDM Rubber
Chloroprene Rubber
Nitrile Rubber
Silicone Rubber
Chlorosulfonated Polyethylene Rubber
Hardness °A
40–100
40–90
40–90
30–90
45–100
40–80
40–80
Excellent
Good
Good
Very good
Excellent
Poor
Fair
Excellent Excellent
Excellent
Excellent
Excellent
Excellent
Abrasive resistance Room temperature aging
Good
Resistance to diffusion of gases
Fair
Excellent
Good
Excellent
Fair
Poor
Poor
Resistance to flexing
Excellent
Excellent
Good
Excellent
Fair
Poor
Poor
Resistance to petrochemicals and greases
Poor
Poor
Poor
Good
Excellent
Fair
Good
Resistance to vegetable oils
Good
Good
Good
Fair
Very good
Good
Good
Resistance to water and antifreezes
Good
Good
Very good
Fair
Good
Poor
Poor
Resistance to dilute acids
Good
Good
Good
Good
Fair
–
Good
Resistance to oxidizing agents
Poor
Fair
Fair
Poor
Poor
Poor
Very good
Continued
233
234
Appendix III
Chemical-Resistant Properties and Hardness Ranges of Both Natural and Synthetic Rubbers—Cont’d Natural Rubber
Butyl Rubber
EPDM Rubber
Chloroprene Rubber
Nitrile Rubber
Silicone Rubber
Chlorosulfonated Polyethylene Rubber
Resistance to alkalis
Fair
Fair
Fair
Good
Fair
–
Good
Processing characteristics
Excellent
Good
Good
Good
Good
–
Poor
Tear resistance
Excellent
Good
Good
Poor
Good
Property
Excellent Excellent
EPDM, Ethylene-propylene-diene-monomer. Note: Higher hardness of 100°A in natural rubber and nitrile rubber indicates that ebonite that can be made with approximately 50% of sulfur addition. • Ebonite cannot be made from butyl, EPDM, chloroprene, silicone, and chlorosulfonated polyethylene. • Silicone rubber has higher temperature resistance. • At room temperature natural rubber can be used for road tankers to handle 70% sulfuric acid. • Neoprene and chlorosulfonated polyethylene can handle pure and strong sodium hydroxide. • Chlorosulfonated polyethylene possesses superior resistance to oxidizing environments such as 90% sulfuric acid and 40% nitric acid at room temperature for short durations.
The chemistry, compounding, and vulcanization of all types of rubbers used for rubber lining applications are quite complex and information is not readily available to chemical engineers. The best practice is to discuss the chemical process with the rubber lining manufacturers and applicators to obtain a proper rubber selection for a given condition and the type of vulcanization, whether by autoclave, precured, open steam curing, hot water curing, or self-curing methods. For immersion testing or for testing the bond
strength of the lining, counter samples are to be lined as representative samples and cured along with the rubber-lined vessel. Although the inherent chemical resistance of the rubber chosen is quite suitable for the given duty conditions, often the bond or adhesion failure is the cause of lining failure. Therefore much care is taken while applying the lining especially at joints, seams, corners, and flanges.
Chemical-Resistant Properties and Hardness Ranges of Both Natural and Synthetic Rubbers
Property
Natural Rubber
Butyl Rubber
EPDM Rubber
Chloroprene Rubber
Nitrile Rubber
Silicone Rubber
Chlorosulfonated Polyethylene Rubber
Hardness °A
40–100
40–90
40–90
30–90
45–100
40–80
40–80
Excellent
Good
Good
Very good
Excellent
Poor
Fair
Excellent Excellent
Excellent
Excellent
Excellent
Excellent
Abrasive resistance Room temperature aging
Good
Resistance to diffusion of gases
Fair
Excellent
Good
Excellent
Fair
Poor
Poor
Resistance to flexing
Excellent
Excellent
Good
Excellent
Fair
Poor
Poor
Resistance to petrochemicals and greases
Poor
Poor
Poor
Good
Excellent
Fair
Good
Resistance to vegetable oils
Good
Good
Good
Fair
Very good
Good
Good
Resistance to water and antifreezes
Good
Good
Very good
Fair
Good
Poor
Poor
Resistance to dilute acids
Good
Good
Good
Good
Fair
–
Good
Resistance to oxidizing agents
Poor
Fair
Fair
Poor
Poor
Poor
Very good
Continued
233
234
Appendix III
Chemical-Resistant Properties and Hardness Ranges of Both Natural and Synthetic Rubbers—Cont’d Natural Rubber
Butyl Rubber
EPDM Rubber
Chloroprene Rubber
Nitrile Rubber
Silicone Rubber
Chlorosulfonated Polyethylene Rubber
Resistance to alkalis
Fair
Fair
Fair
Good
Fair
–
Good
Processing characteristics
Excellent
Good
Good
Good
Good
–
Poor
Tear resistance
Excellent
Good
Good
Poor
Good
Property
Excellent Excellent
EPDM, Ethylene-propylene-diene-monomer. Note: Higher hardness of 100°A in natural rubber and nitrile rubber indicates that ebonite that can be made with approximately 50% of sulfur addition. • Ebonite cannot be made from butyl, EPDM, chloroprene, silicone, and chlorosulfonated polyethylene. • Silicone rubber has higher temperature resistance. • At room temperature natural rubber can be used for road tankers to handle 70% sulfuric acid. • Neoprene and chlorosulfonated polyethylene can handle pure and strong sodium hydroxide. • Chlorosulfonated polyethylene possesses superior resistance to oxidizing environments such as 90% sulfuric acid and 40% nitric acid at room temperature for short durations.
The chemistry, compounding, and vulcanization of all types of rubbers used for rubber lining applications are quite complex and information is not readily available to chemical engineers. The best practice is to discuss the chemical process with the rubber lining manufacturers and applicators to obtain a proper rubber selection for a given condition and the type of vulcanization, whether by autoclave, precured, open steam curing, hot water curing, or self-curing methods. For immersion testing or for testing the bond
strength of the lining, counter samples are to be lined as representative samples and cured along with the rubber-lined vessel. Although the inherent chemical resistance of the rubber chosen is quite suitable for the given duty conditions, often the bond or adhesion failure is the cause of lining failure. Therefore much care is taken while applying the lining especially at joints, seams, corners, and flanges.