Sustained release grouting material with its preparation method and application

A method for preparing sustained-release grouting materials comprising the following steps:

• step 1:
• mixing bentonite, xanthan powder and water to obtain a bentonite wet material;
• step 2:
• adding a high super absorbent polymer (SAP) into the bentonite wet material to pelletize and obtain wet water swelling core particles;
• step 3:
• air drying the wet water swelling core particles at room temperature or oven drying below 60° C. to obtain dry water swelling core particles;
• step 4:
• adding and stirring deionized water in a mixture of water soluble starch, polyvinyl alcohol, and poloxamer, and then adding water soluble lubricants and plasticizers with stirring until completely dissolved to obtain a film forming solution;
• and
• step 5:
• placing the dry water swelling core particles in a coating machine, spraying the film forming solution onto the surface of the rolling dry water swelling core particles, inject hot air to evaporate the deionized water in the film forming solution, and forming a continuous release coating on the surface of the dry water swelling core particles;
• the coating thickness is controlled by adjusting the spraying time of the film forming solution, thereby producing grouting materials with different coating thicknesses;
• obtaining the sustained-release grouting materials after cooling.