Patent ID: 7847049

Claim:
A method for producing a polyrotaxane comprising: an inclusion step in which carboxylated polyethylene glycol having a carboxyl group at each end and cyclodextrin molecules are mixed together, to obtain a pseudopolyrotaxane in which the carboxylated polyethylene glycol is included in the cavities of cyclodextrin molecules in a skewered manner; and a capping step in which capping groups each having a group that reacts with a carboxyl group are reacted with the pseudopolyrotaxane, to obtain a polyrotaxane having at each end a capping group, wherein the carboxylated polyethylene glycol is prepared by oxidation of polyethylene glycol with 2,2,6,6-tetramethyl-1-piperidinyl oxyradical (TEMPO); and the oxidation with TEMPO is conducted in a weakly basic system which is a mixed solution of sodium bromide and sodium hypochlorite in water.