Dispersants

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(C2-4-alkyleneimine) or a moiety which contains said basic group;
• when Z is said polyvinylamine or poly(C2-4-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)nX—;
• when Z is a basic group selected from polyvinylamine or poly(C2-4-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.