Patent ID: 6855752

Claim:
A modified acrylic polymer obtained by reacting (A) a poly(acrylic acid) with endgroups resulting from initiators and/or chain transfer agents that are inert for condensation reactions, said poly(acrylic acid) A-1 having a number average molecular weight of from 500 to 20,000 and (B) o molar parts of a monofunctional polyalkyleneglycol-monoalkylether B-1 HO—(A-O) r —(B—O—) s R 1 B-1 optionally (C) p molar parts of a monofunctional α-amino-polyalkylenglycol- -alkylether C-1 H 2 N—(A-O—) t (B—O—) u R 1 C-1 and optionally (D) molar parts of a primary or secondary amine D-1 wherein R represents a hydrogen atom or a methyl group, or a mixture thereof; M represents a hydrogen atom, a C 1 -C 5 alkyl group or an alkali metal, an alkaline earth metal or other two or three valent metal atoms, an ammonium or organic ammonium group, or a mixture thereof; each R 1 independently from each other is a C 1 -C 4 alkyl group ;A and B represent alkylene groups with 2-4 C-atoms, the mixture of (A-O) and (B-O) is formed by either random addition or block addition, and (A-O)±(B-O); R 2 and R 3 independently from each other represent a hydrogen atom, or an aliphatic, cycloaliphatic, araliphatic or aromatic group, or R 2 and R 3 together with the nitrogen atom to which they are bound form a morpholine or imidazole ring system, or another ring systems containing at least one further hetero atom; or R 2 and R 3 independently from each other represent oxyalkylene groups of the structure R 5 —(O—R 6 ) v , wherein R 5 represents a C 1 -C 4 alkyl group and O—R 6 represents an oxyalkylene group with 2 to 4 carbon atoms, whereby within the same structure R 5 —(O—R 6 ) v —, O—R 6 optionally represents more than one kind of oxyalkylene group, wherein the mixture may-be is formed by either random addition or block addition; wherein a molar ratio of a:o:p:q=1:(0.1-0.95):(0-0.6):(0-0.6), and wherein p+q<0.9, and o+p+q≦a; r, s, t, u and v independently represent integers from 0-250; r+s >1; t+u>1; in the presence of a catalyst at elevated temperatures wherein the degree of reaction is influenced by the ratio of A-1, B-1 and/or and optionally C-1 and optionally D-1 and the temperature, in which the reaction can be followed by decrease of the acid number over time, in which the reaction can be stopped at different reaction times resulting in polymers with different properties, said reaction is stopped I. at a high slope of decrease of the acid number over the time resulting in polymers with a high initial water reduction of >20% and a decreasing slump flow over time or II. at a medium slope of decrease of the acid number over time resulting in polymers with a high or medium initial water reduction of at least 10% and a constant slump flow over the time or III. at a slope of decrease or no decrease of the acid number over time resulting in polymers with a medium or low initial water reduction of at most 20% and an increasing slump flow over the time.