The invention discloses a preparation method of
polycaprolactone. The preparation method comprises the following steps: adding a
solvent into a
raw material, hydrolyzing under an acidic or alkaline condition to form a 6-hydroxy hexanoate solution, removing water and the
solvent from the 6-hydroxy hexanoate solution in a
vacuum pressure environment at a temperature, carrying out 6-hydroxy hexanoate polycondensation at the same time, adjusting according to different molecular weights to obtain
polycaprolactone with a molecular weight greater than 60,000, cooling the
polymerization reaction materials, adding an acid to adjust the materials to be neutral, standing for layering, separating out and removing lower-layer water, washing an
oil phase with water, heating after the
oil phase is qualified, and performing vacuum
dehydration and
drying to obtain a
polycaprolactone finished product. According to the method, waste generated in the production and use process of numerous
caprolactone downstream products can be converted into degradable polycaprolactone products, the cost is low, recycling of the
caprolactone downstream waste is achieved,
environmental protection and
circular economy are facilitated, and the yield of polycaprolactone is increased.