Hard-water-resistant soap with arylsulfobetaine as a lime soap dispersing agent

The invention provides a formula for a hard-water-resistant soap. The formula comprises the following components in percentages by mass: 0.1% to 30% of a dodecyl dimethyl benzylsulfobetaine ampholytic surfactant, 40% to 85% of fatty acid sodium, 0.1% to 20% of glycerol, 0.1% to 1.5% of an antioxidant and 0.1% to 2.0% of essence, with the balance being water or an inorganic filling material. According to the invention, by using the dodecyl dimethyl benzylsulfobetaine ampholytic surfactant as a lime soap dispersing agent, the crystal structure thereof enables the crystal type and molding of the soap body not to be affected; meanwhile, performances like hard-water resistance and wettability of ordinary fatty acid sodium soap are improved. The soap prepared according to the formula of the hard-water-resistant soap is free of unclean feeling or soapy feeling during washing and spray washing, and has no irritation sense and dryness sense after washing; and the hard-water-resistant performance of a laundry block soap prepared according to the formula for the hard-water-resistant soap can meet and exceed the requirements of the national standard (QB/T24872008) of a composite laundry soap.