Aqueous dispersion of polyurethane

An aqueous dispersion of polyurethane, comprising a polyurethane polymer produced by a reaction of a reaction mixture comprising a polyurethane prepolymer A) and an isocyanate-reactive component B), wherein the polyurethane prepolymer A) is produced by a reaction of:

• A1) a polyisocyanate which has a functionality of not less than 2;
• and
• A2) a multifunctional polyether polyol which has a functionality of not less than 3 in an amount of 1% to 30% by weight, based on the amount of the reaction mixture as 100% by weight, the multifunctional polyether polyol having a number-average molecular weight of 1,800 g/mol to 12,000 g/mol, wherein the multifunctional polyether polyol is produced by a reaction of ethylene oxide and an initiator and has a star structure, and wherein the multifunctional polyether polyol has the following structure:
• wherein,
• m is 0 to 50;
• n is 1 to 50;
• m′ is not less than 3;
• X is one or more selected from the group consisting of propyl, isopropyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, styryl, methylstyryl and pinanyl.