Process for remoisturizing surface-postcrosslinked water-absorbing polymer particles

Patent metadata

Field	Value
Publication number	US-10066064-B2
Application number	US-201013498199-A
Country	US
Kind code	B2
Filing date	Oct 5, 2010
Priority date	Oct 9, 2009
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

A process for producing water-absorbing polymer particles, wherein surface postcrosslinked water-absorbing polymer particles are remoisturized and delivered pneumatically, and wherein the time between remoisturization and pneumatic delivery is less than one hour.

First claim

The invention claimed is:

1. A process for producing water-absorbing polymer particles by polymerizing a monomer solution or suspension comprising
at least one ethylenically unsaturated monomer which bears an acid group and may be at least partly neutralized,
at least one crosslinker,
at least one initiator,
optionally one or more ethylenically unsaturated monomer copolymerizable with the ethylenically unsaturated monomer which bears an acid group, and
optionally one or more water-soluble polymer,
then drying, grinding, classifying, and surface postcrosslinking optionally additionally using polyvalent metal cations at 130 to 210° C. to provide dried surface postcrosslinked polymer particles,
then remoisturizing the dried surface postcrosslinked polymer particles by adding an aqueous liquid to the particles,
then pneumatically delivering the remoisturized surface postcrosslinked polymer particles, and
optionally, classifying the remoisturized surface postcrosslinked polymer particles,
wherein a time between the remoisturization and the pneumatic delivery is less than one hour.

2. The process according to claim 1 , wherein the water-absorbing polymer particles are surface postcrosslinked by formation of covalent bonds.

3. The process according to claim 2 , wherein polyvalent metal cations have been used additionally in the surface postcrosslinking.

4. The process according to claim 1 , wherein the water-absorbing polymer particles supplied to the remoisturization have a temperature of 40 to 80° C.

5. The process according to claim 1 , wherein remoisturization is effected using an aqueous solution or an aqueous dispersion comprising an inorganic particulate substance, an inorganic colloidally dissolved substance, an organic polymer, a cationic polymer, and/or a salt of a polyvalent metal cation.

6. The process according to claim 1 , wherein the water-absorbing polymer particles supplied to the pneumatic delivery have a temperature of 40 to 80° C.

7. The process according to claim 1 , wherein an initial velocity in the pneumatic delivery corresponds to a Froude number of from 10 to 18.

8. The process according to claim 1 , wherein at least 95% by weight of the water-absorbing polymer particles have a particle size of at least 150 μm.

9. The process according to claim 1 , wherein at least 95% by weight of the water-absorbing polymer particles have a particle size of at most 600 μm.

10. The process according to claim 1 , wherein the water-absorbing polymer particles have a centrifuge retention capacity of at least 15 g/g.

11. The process according to claim 1 , wherein the time between the moisturization and the pneumatic delivery is less than 45 minutes.

12. The process according to claim 1 , wherein the time between the moisturization and the pneumatic delivery is less than 30 minutes.

13. The process according to claim 1 , wherein the time between the moisturization and the pneumatic delivery is less than 15 minutes.

Assignees

• Funk Ruediger
• Schroeder Juergen
• Pfeiffer Thomas
• Weismantel Matthias
• Basf Se

Inventors

• Funk Rüdiger
• Schröder Jürgen
• Pfeiffer Thomas
• Weismantel Matthias

Classifications

• B07B13/16

  Feed or discharge arrangements · CPC title

• A61L15/60

  Liquid-swellable gel-forming materials, e.g. super-absorbents · CPC title

• C08J2300/14

  Water soluble or water swellable polymers, e.g. aqueous gels · CPC title

• A61L2400/18

  Modification of implant surfaces in order to improve biocompatibility, cell growth, fixation of biomolecules, e.g. plasma treatment · CPC title

• A61L15/22

  containing macromolecular materials · CPC title