US 7,321,006 B2
Admixture for cement
Toshio Hayashiya, Toyono-gun (Japan); Tomiyasu Ueta, Suita (Japan); Tsutomu Yuasa, Osaka (Japan); Tsuyoshi Hirata, Kobe (Japan); and Hiroshi Yamazaki, Sakai (Japan)
Assigned to Nippon Shokubai Co., Ltd., Osaka (Japan)
Filed on Dec. 31, 2004, as Appl. No. 11/26,995.
Claims priority of application No. 2004-000933 (JP), filed on Jan. 06, 2004; and application No. 2004-057996 (JP), filed on Mar. 02, 2004.
Prior Publication US 2005/0182162 A1, Aug. 18, 2005
Int. Cl. C04B 24/26 (2006.01)
U.S. Cl. 524—5  [524/4; 524/556; 524/558; 526/79; 526/240; 526/318.41] 14 Claims
 
1. 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).