Water softener resin is primarily made from two key ingredients: polystyrene and divinylbenzene (DVB).
Here's a breakdown of the process:
-
Raw Materials: The process begins with polystyrene, a plastic material, and divinylbenzene (DVB), a clear yellow liquid that acts as a cross-linking agent. DVB bonds the polystyrene chains together.
-
Polymerization: Polystyrene and DVB undergo a suspension polymerization process. This involves suspending droplets of the raw materials in water.
-
Bead Formation: During polymerization, the materials react and solidify into small, spherical beads. The amount of DVB used determines the degree of cross-linking in the resin beads, which affects their strength and durability. More DVB leads to greater cross-linking.
-
Sulfonation (for Cation Resin): For cation exchange resin (the most common type in water softeners), the polystyrene beads are then sulfonated. This process involves treating the beads with sulfuric acid or another sulfonating agent. This adds negatively charged sulfonate groups to the resin beads. These groups attract positively charged ions (like calcium and magnesium) in the water.
-
Amination (for Anion Resin): For anion exchange resin (used for removing nitrates, sulfates, etc.), the beads undergo amination, where amine groups are attached to the resin.
-
Washing and Screening: The resin beads are thoroughly washed to remove any unreacted chemicals or byproducts. They are then screened to ensure a uniform size. Consistent bead size is important for efficient water softening.
-
Packaging: Finally, the finished resin beads are packaged and ready for use in water softening systems.
In summary, water softener resin is manufactured through a polymerization process using polystyrene and divinylbenzene to create beads, followed by sulfonation or amination (depending on the type of resin) to give them their ion-exchange properties.
