Abstract: A coated ?-sulfofatty acid alkyl ester salt particle group containing ?-sulfofatty acid alkyl ester salt particles (A) and a zeolite particle group-containing coating component (B) with which the particles (A) are coated, in which the zeolite particle group is a zeolite particle group (b1) having a mean particle size of equal to or greater than 0.8 ?m and less than 3.8 ?m.

Abstract: A coated ?-sulfofatty acid alkyl ester salt particle group containing ?-sulfofatty acid alkyl ester salt particles (A) and a zeolite particle group-containing coating component (B) with which the particles (A) are coated, in which the zeolite particle group is a zeolite particle group (b1) having a mean particle size of equal to or greater than 0.8 ?m and less than 3.8 ?m.

Abstract: The invention provides a fatty acid alkyl ester sulfonate metal salt mixture of (a) a fatty acid alkyl ester sulfonate metal salt having an endothermic peak area at 50 to 130° C. of less than 50% relative to the whole endothermic peak area at 0 to 130° C. as measured on a differential scanning calorimeter, and (b) a fatty acid alkyl ester sulfonate metal salt having an endothermic peak area at 50 to 130° C. of 50% or more relative to the whole endothermic peak area at 0 to 130° C. as measured on a differential scanning calorimeter, with a ratio of (a) to (b) by mass of 95/5 or less. The mixture of the invention is excellent in anti-caking properties.

Abstract: The invention provides a fatty acid alkyl ester sulfonate metal salt mixture of (a) a fatty acid alkyl ester sulfonate metal salt having an endothermic peak area at 50 to 130° C. of less than 50% relative to the whole endothermic peak area at 0 to 130° C. as measured on a differential scanning calorimeter, and (b) a fatty acid alkyl ester sulfonate metal salt having an endothermic peak area at 50 to 130° C. of 50% or more relative to the whole endothermic peak area at 0 to 130° C. as measured on a differential scanning calorimeter, with a ratio of (a) to (b) by mass of 95/5 or less. The mixture of the invention is excellent in anti-caking properties.

Abstract: The present invention relates to a method for producing an aqueous ?-SF salt solution that maintains fluidity and has superior production adaptability. The method includes dissolving a solid component (a) in the form of an ?-sulfo fatty acid alkyl ester salt and a component (b) in the form of an inorganic sodium salt and/or inorganic potassium salt in water, wherein component (a) is dissolved in water at a temperature of 50° C. or higher while maintaining the following condition (i) or (ii): (i): the concentration of component (a) is 35% by weight or less when the total concentration of sodium and potassium ions derived from component (b) is less than 0.55 mol/kg, or (ii) the concentration of component (a) is 55% by weight or less when the total concentration of sodium and potassium ions derived from component (b) is 0.55 mol/kg to less than 1.8 mol/kg.

Abstract: The present invention relates to a method for producing an aqueous ?-SF salt solution that maintains fluidity and has superior production adaptability. The method includes dissolving a solid component (a) in the form of an ?-sulfo fatty acid alkyl ester salt and a component (b) in the form of an inorganic sodium salt and/or inorganic potassium salt in water, wherein component (a) is dissolved in water at a temperature of 50° C. or higher while maintaining the following condition (i) or (ii): (i): the concentration of component (a) is 35% by weight or less when the total concentration of sodium and potassium ions derived from component (b) is less than 0.55 mol/kg, or (ii) the concentration of component (a) is 55% by weight or less when the total concentration of sodium and potassium ions derived from component (b) is 0.55 mol/kg to less than 1.8 mol/kg.

Abstract: A process for producing powder, flakes, or pellets containing ?-sulfo fatty acid alkylester salt in high concentrations, the process including: (1) a step of preparing a paste containing ?-sulfo fatty acid alkylester salt; (2) a step of aging the thus obtained paste; (3) a step of making the aged paste into flakes or pellets containing equal to or less than 10 wt % of water and then optionally crushing the resulting flakes or pellets into a powder having an average particle diameter of 100-1500 ?m; and (4) a step of aging The powder, flakes, or pellets.

Abstract: A process for producing powder, flakes, or pellets containing ?-sulfo fatty acid alkylester salt in high concentrations, the process including: (1) a step of preparing a paste containing ?-sulfo fatty acid alkylester salt by a series of reactions of sulfonating a fatty acid alkylester with a sulfonating gas by contact with each other, esterifying the sulfonated product with a lower alcohol, neutralizing the esterified product, and bleaching the neutralized product, to give a paste containing ?-sulfo fatty acid alkylester salt; (2) a step of aging the thus obtained paste; (3) a step of making the aged paste into flakes or pellets containing equal to or less than 10 wt % of water, or a step of making the aged paste into flakes or pellets containing equal to or less than 10 wt % of water and then crushing the resulting flakes or pellets into a powder having an average particle diameter of 100-1500 ?m; and (4) a step of aging the powder, flakes, or pellets.