Method for producing a solid with sufficiently low hygroscopicity which comprises glutamic acid-N,N-diacetic acid (GLDA) or a derivative thereof

A solid, comprising:

• (1) a core comprising at least one selected from the group consisting of glutamic acid-N,N-diacetic acid, a salt of glutamic acid-N,N-diacetic acid, and a derivative thereof;
• and
• (2) a coating comprising a compound of formula (I):
• wherein:
• R represents
• a C1- to C30-alkyl or C2- to C30-alkenyl, additionally substituted with up to 5 hydroxyl groups, formyl groups, C1- to C4-alkoxy groups, phenoxy groups or C1- to C4-alkoxycarbonyl groups, and optionally interrupted by up to 5 nonadjacent oxygen atoms,
• an alkoxylate group of the formula (Ia):
• —(CH2)k—O-(A1O)m-(A2O)n—Y (Ia),
• wherein
• A1 and A2, independently, represent 1,2-alkylene groups having 2 to 4 carbon atoms,
• Y represents hydrogen, C1- to C12-alkyl, phenyl or C1- to C4-alkoxycarbonyl,
• k represents the number 1, 2 or 3, and
• m and n, independently, represent a number from 0 to 50, such that a sum of m+n is at least 4,
• a phenylalkyl group having 1 to 20 carbon atoms in the alkyl,
• a five- or six-membered unsaturated or saturated heterocyclic ring having up to three heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur, optionally benzo-fused,
• such that all of the phenyl rings and heterocyclic rings specified in the meanings for R are optionally substituted with up to three C1- to C4-alkyl groups, hydroxyl groups, carboxyl groups, sulfo groups, C1- to C4-alkoxycarbonyl groups, or mixtures thereof, or
• a radical of for the formula (Ib):
• wherein A represents a C1- to C12-alkylene bridge or a chemical bond;
• and
• each M, independently, represents hydrogen, alkali metal, alkaline earth metal, ammonium or substituted ammonium, in corresponding stoichiometric amounts.