Patent ID: 8772435

Claim:
A dispersant of formula 1: T-(A) m (B) n —X—Z-Q (0-p) Formula (1) including salts thereof wherein -(A) m (B) n — is the reaction product of at least one hydroxy carboxylic acid or lactone thereof and at least one amino carboxylic acid at 50 C to 250 C optionally in the presence of a esterification catalyst where m and n are as described below; T is hydrogen or a polymerisation terminating group; A is an oxyalkylene carbonyl residue of a hydroxy carboxylic acid or lactone thereof; B is derived from said amino carboxylic acid; X is a direct bond or a divalent linking group; Z is a basic group of 1000 to 200,000 g/mole number average molecular weight selected from polyvinylamine or poly(C 2-4 -alkyleneimine) or a moiety which contains said basic group; when Z is said polyvinylamine or poly(C 2-4 -alkyleneimine), Q is an oxygen atom of a N-oxide reaction product of amino or imino groups of Z reacted with oxygen or a peroxide, or a reaction product of said amino or imino groups reacted with dibasic acid or anhydride thereof; m and n are non-zero positive integers m+n is from 4 to 2000; (0-p) means from the value 0 to the value p; p represents the maximum available number of amino and/or imino groups in Z which does not carry the group T-(A) m (B) n X—; when Z is a basic group selected from polyvinylamine or poly(C 2-4 -alkyleneimine) or a moiety which contains said basic group there may be more than one group T-(A) m (B) n —X— attached to Z and said more than one group may be chemically the same or different.