Patent ID: 11964032
Assignee: WANHUA CHEMICAL GROUP CO., LTD.
Field: Pharmaceuticals (Chemistry)
Classification: CPC A  C | IPC A  C

Claim 1:
2. The mask substrate composition according to claim 1, wherein (a) the aqueous polyurethane dispersion (a) is prepared according to a method comprising the following steps: mixing (a2) the polyester polyol and (a3) the low-molecular weight diol chain extender at 70-80° C., lowering the temperature of the resulting mixture to 45-60° C., and then adding (a1) the polyisocyanate for a prepolymerization reaction; cooling the resulting prepolymer to 30-45° C. when the theoretical NCO content is reached, and dissolving the prepolymer in an acetone solvent in which the usage amount of acetone is 100-150 wt % of the mass of the polyurethane in (a) the aqueous polyurethane dispersion OA; after mixing the prepolymer and the acetone solvent, adding (a4) the polyamine chain extender (a) and (a5) the polyamine chain extender (b), continuing the reaction at 35-45° C. for 15-30 min, adding water under shear and dispersion conditions in which the usage amount of water is 130-200 wt % of the mass of the polyurethane in (a) the aqueous polyurethane dispersion (a), adding an aqueous solution of (a6) the small-molecule monoamino end-capping agent for end-capping, removing the acetone under vacuum, and obtaining (a) the aqueous polyurethane dispersion (a); and
the total solids content of (a) the aqueous polyurethane dispersion (a) is 20-50 wt %; and the particle size is 100 nm-300 nm.