Method for producing water-absorbing polymer particles

• US 7,910,675 B2
• Filed: 08/10/2006
• Issued: 03/22/2011
• Est. Priority Date: 08/24/2005
• Status: Active Grant

• Current Assignee: BASF SE
• Original Assignee: BASF SE
• Inventors: Schröder, Jürgen, Funk, Rüdiger
• Primary Examiner(s): Wu; David
• Assistant Examiner(s): Nguyen; Vu A
• Application Number:
  US11/997,941
• Publication Number:
  US 20080227932A1
• Time in Patent Office: 1,685 Days
• Field of Search: 526/65, 526/317.1, 526/930
• US Class Current: 526/317.1
• CPC Class Codes: B01J 19/0006 Controlling or regulating processes controlling or regulating in general G05
• CPC Class Codes: B01J 19/22 in the form of endless belts
• CPC Class Codes: B01J 19/2445 placed in parallel
• CPC Class Codes: B01J 2219/00033 Continuous processes
• CPC Class Codes: B01J 2219/00038 Processes in parallel
• CPC Class Codes: C08F 2/01 characterised by special features of the polymerisation apparatus used
• CPC Class Codes: Y10S 526/93 Water swellable or hydrophilic

Abstract

A process for producing water-absorbing polymeric particles comprises conducting the polymerization in at least two parallel continuous polymerization reactors under substantially identical conditions and further processing the reaction products conjointly in at least one process step.

Claims

1. A process for producing water-absorbing polymeric particles, which comprises conducting a polymerization in at least two parallel continuous polymerization reactors under substantially identical conditions and further processing reaction products conjointly in at least one process step.

2. The process according to claim 1 wherein at least one of the parallel polymerization reactors is a belt reactor and/or a kneader.

3. The process according to claim 1 wherein the parallel polymerization reactors are exclusively belt reactors or kneaders.

4. The process according to claim 1 wherein the reaction products of the parallel polymerization reactors are conjointly subjected to a postcrosslinking step.

5. The process according to claim 1 wherein the reaction products of the parallel polymerization reactors are conjointly screened.

6. The process according to claim 1 wherein the reaction products of the parallel polymerization reactors are conjointly ground.

7. The process according to claim 1 wherein the reaction products of the parallel polymerization reactors are conjointly dried.

8. The process according to claim 7 wherein the dryer is a belt dryer.

9. The process according to claim 1 wherein the reaction products of the parallel polymerization reactors are conjointly stored before drying.

10. The process according to claim 1 wherein a monomer solution polymerized in the parallel polymerization reactors comprises acrylic acid and at least one crosslinker copolymerizable with acrylic acid.

11. The process according to claim 1 wherein the polymerization is carried out in the presence of less than 0.016% by weight, based on monomers, of a polymerization inhibitor.

12. The process according to claim 4 wherein the reaction products of the parallel polymerization reactors are conjointly screened.

13. The process according to claim 4 wherein the reaction products of the parallel polymerization reactors are conjointly ground.

14. The process according to claim 4 wherein the reaction products of the parallel polymerization reactors are conjointly dried.

15. The process according to claim 5 wherein the reaction products of the parallel copolymerization reactors are conjointly ground.

16. The process according to claim 5 wherein the reaction products of the parallel copolymerization reactors are conjointly dried.

17. The process according to claim 1 wherein the reaction products of the parallel polymerized reactors are processed conjointly in at least two of a surface crosslinking step, screening, grinding, drying, and storing.