Patent ID: 7321006

Claim:
A polycarboxylic acid-based polymer for an admixture for cement, which is characterized in that a lower molecular weight side area ratio P defined by the following steps (1) to (6) is 50 to 87%: (1) performing a measurement by gel permeation chromatography (GPC), and obtaining a GPC chart; (2) drawing a baseline in a GPC chart, expressing by Lh an intersection point between a higher molecular weight side of the GPC chart and a baseline, and expressing by Ln an intersection point between a lower molecular weight side of the GPC chart and a baseline; (3) expressing by Lp an intersection point between a line which passes through i) a peak Mp (when there are plural peaks, a peak on a lowest molecular weight side) of a GPC chart and is vertical to a baseline, and ii) the baseline; (4) expressing by Lm a middle point between Lp and Lh; (5) expressing by P0 an area under a curve on a lower molecular weight side between Ln and Lp, and expressing by Q0 an area under a curve on a higher molecular weight side between Lh and Lm; and (6) defining a lower molecular weight side area ratio P (%) as P=(P0×100)/(P0+Q0).