This materials that absorb water (SAP) is generally a polymer electrolyte containing a hydrophilic group and a crosslinked structure. Before absorbing water, the polymer chains are entangled with each other and crosslinked with each other to form a network structure, thereby achieving overall fastening. When in contact with water, water molecules penetrate into the resin through capillary action and diffusion, and the ionizing groups on the chain are ionized in water. Due to the electrostatic repulsion between the same ions on the chain, the polymer chain stretches and swells. Due to the requirement of electrical neutrality, the counterions cannot migrate to the outside of the resin(instead of super absorbent polymer), and the difference in ion concentration between the solution inside and outside the resin forms the reverse osmotic pressure. Water further enters the SAP under the action of reverse osmotic pressure to form a hydrogel. At the same time, the cross-linked network structure and hydrogen bonding of the resin itself limit the infinite expansion of the gel.

After neutralizing acrylic acid or sodium acrylate with alkali, adding a pre-crosslinking agent and initiator to carry out the polymerization reaction. Then drying and crushing after obtaining the hydrogel, and crushing gel particles during the crushing process will also produce dispersion fine powder. Secondary granulation of the fine powder, adding fumed silica during the secondary granulation process and then granulating together with the crushed gel particles. The resulting granulated material is mixed with water and post-crosslinking agent surface treatment in the heat treatment liquid, that is, a highly absorbent polymer.