Block polymers containing ester groups as defoamers for aqueous systems

A method of regulating the foaming of water-based systems with a tendency to foam, said method comprising adding to a water-based system with a tendency to foam a block copolymer containing ester groups, said block copolymer corresponding to the general formula (II):

• R.sup.1 (--O--R--CO).sub.a --(OCH.sub.2 CH.sub.2).sub.n --(O--OC--R).sub.b --OR.sup.2 (II)
• in which "n" is a number of 6 to 100, R is a linear or branched alkylene or alkenylene radical containing 2 to 18 carbon atoms, "a" is a number of 2 to 170, "b" is a number of 1 to 170 and R.sup.1 and R.sup.2 represent hydrogen.

A granular free-flowing foam regulating formulation comprising 0.5% by weight to 30% by weight of a block copolymer containing ester groups, said block copolymer corresponding to the general formula (I):

• A--(CH.sub.2 CH.sub.2 O).sub.n --B (I)
• in which n is an integer of 4 to 300, A is a hydroxycarboxylic acid residue and B is hydrogen, an alkyl or alkenyl radical containing 1 to 22 carbon atoms, a phenyl or benzyl radical or has the same meaning as A, said block copolymer being adsorbed onto 70% by weight to 99.5% by weight of a granular, substantially inorganic phosphate-free support material.

A granular free-flowing foam regulating formulation comprising 2% by weight to 12% by weight of a block copolymer containing ester groups, said block copolymer corresponding to the general formula (II):

• R.sup.1 (--O--R--CO).sub.a --(OCH.sub.2 CH.sub.2).sub.n --(O--OC--R).sub.b --OR.sup.2 (II)
• in which "n" is a number of 6 to 100, R is a linear or branched alkylene or alkenylene radical containing 2 to 18 carbon atoms, "a" is a number of 2 to 170, "b" is a number of 1 to 170 and R.sup.1 and R.sup.2 represent hydrogen, said block copolymer being adsorbed onto 88% by weight to 98% by weight of a granular, substantially inorganic phosphate-free support material.