US 12,226,296 B2
Method for producing absorbent articles comprising water-absorbing resin
Carolin Michaela Borgmann, Eschborn (DE); Heike Opper, Bad Soden (DE); Arsen Arsenov Simonyan, Koenigstein (DE); Yoshiro Mitsukami, Himeji (JP); and Keisuke Kikuchi, Himeji (JP)
Assigned to The Procter & Gamble Company, Cincinnati, OH (US)
Filed by The Procter & Gamble Company, Cincinnati, OH (US)
Filed on Mar. 18, 2022, as Appl. No. 17/698,069.
Claims priority of application No. 2021-045197 (JP), filed on Mar. 18, 2021; and application No. 2021-206110 (JP), filed on Dec. 20, 2021.
Prior Publication US 2022/0296438 A1, Sep. 22, 2022
Int. Cl. A61F 13/53 (2006.01); A61F 13/00 (2024.01); C08F 2/10 (2006.01); C08F 6/06 (2006.01); C08F 20/06 (2006.01); C08J 3/24 (2006.01); A61F 13/15 (2006.01)
CPC A61F 13/53 (2013.01) [C08F 2/10 (2013.01); C08F 6/06 (2013.01); C08F 20/06 (2013.01); C08J 3/245 (2013.01); A61F 2013/15463 (2013.01); A61F 2013/530591 (2013.01); A61F 2013/530729 (2013.01); A61F 2013/530737 (2013.01)] 12 Claims
 
1. A method for producing an absorbent article comprising a surface-crosslinked particulate poly(meth)acrylic acid (salt)-based water-absorbing resin, said method comprising the steps of:
(i) preparing a (meth)acrylic acid (salt)-based aqueous monomer solution;
(ii) polymerizing the (meth)acrylic acid (salt)-based aqueous monomer solution;
(iii) carrying out gel-crushing of a crosslinked hydrogel polymer generated during or after the polymerization to obtain a particulate hydrogel;
(iv) drying the particulate hydrogel to obtain a dried polymer;
(v) pulverizing and/or classifying the dried polymer to obtain a particulate water-absorbing resin before surface-crosslinking;
(vi) surface-crosslinking the particulate water-absorbing resin before surface-crosslinking; and
(vii) incorporating the surface-crosslinked particulate water-absorbing resin in an absorbent article, wherein
in the step (i) and/or the step (ii), water-soluble polyalkylene glycol having a weight average molecular weight of not more than about 2000 is added to the aqueous monomer solution so that a total amount of the water-soluble polyalkylene glycol added in the step (i) and/or the step (ii) is about 0.01 mass % to about 1 mass % relative to a total mass of a monomer included in the aqueous monomer solution,
the crosslinked hydrogel polymer has a centrifuge retention capacity of not more than about 31 g/g and not less than about 20 g/g, and
the surface-crosslinked particulate poly(meth)acrylic acid (salt)-based water-absorbing resin obtained by said method satisfies (1) to (4) below:
(1) a centrifuge retention capacity (CRC) of not less than about 20 g/g and not more than about 35 g/g;
(2) an absorption against pressure (AAP), measured under a load of about 0.7 psi, of not less than about 25 g/g;
(3) a saline flow conductivity (SFC) of not less than about 15 (×about 10−7 cm3·sec/g); and
(4) a free swell rate (FSR) of not less than about 0.33 g/(g·s).