Sodium polyacrylate (ACR) , also known as water lock, is a sodium salt of polyacrylic acid with the chemical formula [−CH2−CH(CO2Na)−]n and has broad applications in consumer products. Sodium polyacrylate is an anionic polyelectrolyte with negatively charged carboxylic groups in the main chain. Sodium polyacrylate is a chemical polymer made up of chains of acrylate compounds. It contains sodium, which gives it the ability to absorb large amounts of water. When dissolved in water, it forms a thick and transparent solution due to the ionic interactions of the molecules. Sodium polyacrylate has many favorable mechanical properties. Some of these advantages include good mechanical stability, high heat resistance, and strong hydration. It has been used as an additive for food products including bread, juice, and ice cream.