| 摘要 |
<p>A hydrous gel polymer prepared by polymerizing a monomer component containing acrylic acid (or a salt thereof) is post-neutralized so that each polymer particle derived from a polymer prepared by neutralizing the hydrous gel polymer has an acceptable degree of neutralization. Thereafter, the polymer prepared by neutralizing the hydrous gel polymer is reacted with a cross-linking agent reactive with the functional groups contained in the polymer. The acceptable degree of neutralization refers to, for example, a degree of neutralization which is at most 20 mol % lower than the average degree of neutralization of the agglomerate of the polymer particles or a degree of neutralization which exceeds at least 55 mol % of the average degree of polymerization of the agglomerate of the polymer particles. The post-neutralization is conducted so that, among 200 particles of the polymer, the number of polymer particles having an unacceptable degree of neutralization outside the obove range of the acceptable degree of neutralization is 10 or less. The water-absorbent thus prepared has a high absorption ratio under ordinary or high pressure, is reduced in the water-solubles content as compared with the conventional water-absorbent, and causes no significant change in the pH of swollen gel.</p> |
