Water Resistant Rubber
Before we look at what types of rubber are compatible with water, let us first look at the different types of water and its use in certain industries. Many applications are designed around water such as irrigation, faucets, shower heads, filtration, underwater equipment. Most applications are sealing in or out municipal (tap) water or salt water, such as ocean equipment. Most rubbers are compatible with basic H2O. It’s what is put in the H20 that can react with rubber. For instance, chloramine treatment of municipal water has a serious affect on certain rubber materials. Chloramine resistant rubber material such as EPDM with a peroxide cure works well with chloramine treated water.
Chloramine Formation
Inorganic chloramines are formed during a reaction between dissolved chlorine and ammonia. There are three types of inorganic chloramines formed, monochloramines (NH2CL), dicloramines (NHCl2) and trichloramines (NCl3).
Monochloramines are formed when the water is alkaline with a pH of greater than 7, dichloramines are formed when the chlorine to ammonia-nitrogen is greater the 5:1 and the water has a pH between 4 and 7. According to the EPA (epa.gov/sites/production/files/2015-09/documents/q1.pdf) Dichloramines are formed when the ammonia concentrations are higher then 5:1 and trichloramines can form when the water is acidic with a pH level below 4.4 or the chlorine to ammonia-nitrogen weight ratio is greater the 7.6:1. Trichloamines can also form if the chlorine to ammonia-nitrogen weight ratio is increased to 15:1 with a pH level between 7 to 8. Trichloramines don’t usually form under normal municipal drinking water treatment but are most commonly found in and around swimming pools.
Industries
