发明名称 |
Particulate water absorbing agent comprising crosslinked absorbent resin and having low residual monomer, water absorbing article and method for production of water absorbing agent |
摘要 |
An object of the present invention is to provide a water absorbing agent having a low amount of residual monomer, small variance of the amount of residual monomer among ranges of particle size distribution and favorable absorption properties, and being sanitary; an absorbing article; and a method for the production of a water absorbing agent. The water absorbing agent of the present invention has the amount of residual monomer of not higher than 500 ppm, and a residual monomer index of not greater than 0.30. The method for the production includes a first step of obtaining a hydrogel polymer by polymerizing an aqueous solution of a monomer including an unsaturated carboxylic acid and/or a salt thereof in the presence of a crosslinking agent; a second step of obtaining a water absorbent resin precursor which is in powder form and includes particles having a particle size of 300 to 850 μm and particles having a particle size of smaller than 300 μm as main components by drying said hydrogel polymer followed by pulverization and classification to adjust the particle size distribution, a third step of obtaining a water absorbent resin by heating a mixture of said water absorbent resin precursor and a surface crosslinking agent, which can form an ester bond around the surface of said water absorbent resin precursor, a fourth step of adding by spraying an aqueous solution that includes a sulfur-containing reducing agent to said water absorbent resin, and a fifth step of subjecting the mixture of the water absorbent resin and said aqueous solution to a heat treatment under an airflow of not lower than 40° C. but not higher than 120° C. |
申请公布号 |
US8182916(B2) |
申请公布日期 |
2012.05.22 |
申请号 |
US20060816200 |
申请日期 |
2006.02.10 |
申请人 |
KIMURA KAZUKI;FUJINO SHIN-ICHI;WADA KATSUYUKI;ISHIZAKI KUNIHIKO;NIPPON SHOKUBAI CO., LTD. |
发明人 |
KIMURA KAZUKI;FUJINO SHIN-ICHI;WADA KATSUYUKI;ISHIZAKI KUNIHIKO |
分类号 |
B32B5/16;C08F2/10;C08F8/34;C08J3/24 |
主分类号 |
B32B5/16 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|