Hydrophobic alginic acid particle group and method for producing same

Hydrophobic alginic acid particles obtained by hydrophobizing a polyvalent metal salt of alginic acid using at least one hydrophobizing agent, wherein

• the hydrophobic alginic acid particles comprise ion-crosslinked polyvalent metal ions,
• the at least one hydrophobizing agent is at least one selected from the group consisting of salts of carboxylic acids, salts of amino acids, salts of amino acid derivatives, salts of sulfate esters, salts of sulfonic acids, and salts of phosphate esters,
• the at least one hydrophobizing agent gives rise to ion exchange with at least some of the ion-crosslinked polyvalent metal ions, accompanied by chemical bonding with the at least one hydrophobizing agent,
• the particles have a water absorption per 100 g of particles and an oil absorption per 100 g of particles such that the water absorption is lower than the oil absorption, and
• letting SD1, SD2 and SD3 be the respective percent transmittances to 560 nm wavelength light of a dispersion prepared by dispersing the hydrophobic alginic acid particles in a 3 wt % aqueous solution of sodium chloride to a concentration of 0.1 wt % when 72 hours, 240 hours and 720 hours have elapsed following preparation, and letting WD1, WD2 and WD3 be the respective percent transmittances to 560 nm wavelength light of a dispersion prepared by dispersing the hydrophobic alginic acid particles in water to a concentration of 0.1 wt % when 72 hours, 240 hours and 720 hours have elapsed following preparation, at least one of the ratios WD1/SD1, WD2/SD2 and WD3/SD3 is 0.9 or less.