Method for producing pseudopolyrotaxane aqueous dispersion
The present invention aims to provide an industrially advantageous method for producing an aqueous dispersion of pseudopolyrotaxane enabling to produce an aqueous dispersion of pseudopolyrotaxane having good fluidity and excellent dispersion stability of the pseudopolyrotaxane particles therein. The present invention relates to a method for producing an aqueous dispersion of pseudopolyrotaxane. The method includes: a mixing step of a dissolving polyethylene glycol and a cyclodextrin in an aqueous medium to prepare a mixed solution; and a cooling step of continuously or intermittently cooling the mixed solution in a state of flux to precipitate pseudopolyrotaxane particles. The pseudopolyrotaxane particles contain the polyethylene glycol which is included in the cavities of the cyclodextrin molecules in a skewered manner.
1. A method for producing an aqueous dispersion of pseudopolyrotaxane, the method comprising:
a mixing step of dissolving polyethylene glycol and cyclodextrin in an aqueous medium so as to prepare a mixed solution; and
a cooling step of continuously or intermittently cooling the mixed solution in a flux state without being left to stand so as to precipitate pseudopolyrotaxane particles,
wherein a weight ratio between polyethylene glycol and cyclodextrin is in a range from 1:3 to 1:5,
the pseudopolyrotaxane particles contain the polyethylene glycol that is included in the cavities of the cyclodextrin molecules in a skewered manner,
wherein an end-point temperature of the cooling in the cooling step is in a range from 5° C. to 20° C.,
a cooling speed in the cooling step is in a range from 0.01° C. to 30° C./min,
the cooling step of the continuously or intermittently cooling the mixed solution is preformed while continuously stirring the mixed solution with a stirring blade, and
a tip speed of the stirring blade used in the cooling step is in a range from 0.1 to 50 m/sec.
2. The method for producing the aqueous dispersion of pseudopolyrotaxane according to claim 1 ,
wherein the polyethylene glycol has a weight average molecular weight in a range from 1,000 to 500,000.
3. The method for producing the aqueous dispersion of pseudopolyrotaxane according to claim 1 ,
wherein the aqueous dispersion of pseudopolyrotaxane has a solid concentration in a range from 5 to 25% by weight.
4. The method for producing the aqueous dispersion of pseudopolyrotaxane according to claim 1 ,
wherein the particles in the aqueous dispersion of pseudopolyrotaxane have a volume average particle size in a range from 1 to 200 μm.