METHOD FOR PREPARING A FLEXIBLE SUPERABSORBENT BINDER POLYMER COMPOSITION

• US 20070129517A1
• Filed: 11/17/2006
• Published: 06/07/2007
• Est. Priority Date: 12/02/2005
• Status: Active Grant

• Current Assignee: Evonik Superabsorber LLC, Stockhausen Incorporated
• Original Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Inventors: Smith, Scott, Ahmed, Iqbal, Lostocco, Michael, Bunyard, W., Soerens, Dave, Lang, Angela
• Granted Patent: US 7,335,713 B2
• Time in Patent Office: Days
• US Class Current: 526/317.100
• CPC Class Codes: C08F 220/06 Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
• CPC Class Codes: C08F 220/26 Esters containing oxygen in addition to the carboxy oxygen
• CPC Class Codes: C08F 230/085 the monomer being a polymerisable silane, e.g. (meth)acryloyloxy trialkoxy silanes or vinyl trialkoxysilanes

Abstract

A process of making the flexible superabsorbent binder polymer composition includes preparing a preneutralized monomer solution having at least about 40 mol % degree of neutralization, preparing a monomer solution including monoethylenically unsaturated monomers, one of which includes an alkyloxysilane functionality, preparing initiator system solutions and adding the solutions to the monomer solution, mixing the foregoing solutions into a polymerization solution, cooling the polymerization solution, and post neutralizing the polymer.

Claims

1. A process for making a flexible superabsorbent binder polymer composition comprising the steps of:

a) preparing a preneutralized monomer solution where the acidic monomer is at least partially neutralized;

b) adding a mixture of low molecular weight polyolefinic glycols having a molecular weight from about 200 to about 10,000, and an ethylenically unsaturated monomer containing a trialkoxysilane functional group to the preneutralized monomer solution;

c) preparing at least 2 initiator system solutions;

d) continuously adding the monomer solution of step b) during polymerization and the at least 2 initiator system solutions of step c) to water to form a mixture wherein the mixture reacts to form a polymer;

e) optionally adding the at least 2 initiator system solutions of step c) at an accelerated flow rate;

f) cooling the polymer; and

g) post-neutralizing the cooled polymer of step f) to increase the neutralization of the polymer to at least about 60 mol %.

2. The process to make the flexible superabsorbent binder polymer composition of claim 1 wherein the preneutralized monomer solution comprises acrylic acid.

3. The process to make the flexible superabsorbent binder polymer composition of claim 1 wherein the initiator system comprises an initiator selected from an oxidizing agent and a reducing agent.

4. The process to make the flexible superabsorbent binder polymer composition of claim 1 wherein the oxidizing agent is hydrogen peroxide and the reducing agent is sodium erythorbate.

5. The process to make the flexible superabsorbent binder polymer composition of claim 1 wherein the mole ratio of oxidizing agent to the reducing agent is from about 6:

1 to about 2;

1.

6. The process to make the flexible superabsorbent binder polymer composition of claim 1 wherein the polymerization solution is cooled in step g) to from about 20°

C. to about 40°

C.

7. The process to make the flexible superabsorbent binder polymer composition of claim 1 wherein the ethylenically unsaturated monomer containing a trialkoxysilane functional group is methacryloxypropyl trimethoxy silane (MEMO).

8. The process to make the flexible superabsorbent binder polymer composition of claim 1 wherein the low molecular weight polyolefinic glycols is a polyethylene glycol (PEG).

9. A flexible superabsorbent binder polymer composition of claim 1.

10. A process for making a flexible superabsorbent binder polymer composition comprising the steps of:

a) preparing a monomer solution where the acidic monomer is at least partially neutralized;

b) adding a chain transfer agent to the monomer solution;

c) adding a mixture of low molecular weight polyolefinic glycols having a molecular weight from about 200 to about 10,000, and an ethylenically unsaturated monomer containing a trialkoxysilane functional group to the monomer solution;

d) preparing at least 2 initiator system solutions and adding the initiator system solutions to the monomer solution wherein the mixture reacts to form a polymer;

e) cooling the polymer of step d); and

f) post-neutralizing the cooled polymer of step e) to increase the neutralization of the polymer to at least about 60 mol %.

wherein the mole ratio of oxidizing agent to the reducing agent is from about 6;

1 to about 2;

1.

11. The process to make the flexible superabsorbent binder polymer composition of claim 10 wherein the preneutralized monomer solution comprises acrylic acid.

12. The process to make the flexible superabsorbent binder polymer composition of claim 10 wherein the initiator system comprises an initiator selected from an oxidizing agent and a reducing agent.

13. The process to make the flexible superabsorbent binder polymer composition of claim 10 wherein the oxidizing agent is hydrogen peroxide and the reducing agent is sodium erythorbate.

14. The process to make the flexible superabsorbent binder polymer composition of claim 10 wherein the polymerization solution is cooled in step e) to from about 20°

C. to about 40°

C.

15. The process to make the flexible superabsorbent binder polymer composition of claim 10 wherein the ethylenically unsaturated monomer containing a trialkoxysilane functional group is methacryloxypropyl trimethoxy silane (MEMO).

16. The process to make the flexible superabsorbent binder polymer composition of claim 10 wherein the low molecular weight polyolefinic glycols is a polyethylene glycol (PEG).

17. A flexible superabsorbent binder polymer composition of claim 10.

18. A process for making a flexible superabsorbent binder polymer composition comprising the steps of:

a) preparing a preneutralized monomer solution, having at least about 40 mol % degree of neutralization comprising a chain transfer agent, and a mixture of low molecular weight polyolefinic glycols having a molecular weight from about 200 to about 10,000, and an ethylenically unsaturated monomer containing a trialkoxysilane functional group;

b) preparing at least 2 initiator system solutions;

c) continuously adding the monomer solution of step a) during polymerization and the at least 2 initiator system solutions of step b) to water to form a mixture wherein the mixture reacts to form a polymer;

d) adding the at least 2 initiator system solutions of step b) at an accelerated flow rate;

e) cooling the polymer of step d); and

f) post-neutralizing the cooled polymer of step e) to increase the neutralization of the polymer to at least about 60 mol %.

19. The process to make the flexible superabsorbent binder polymer composition of claim 18 wherein the preneutralized monomer solution comprises acrylic acid.

20. The process to make the flexible superabsorbent binder polymer composition of claim 18 wherein the initiator system comprises an initiator selected from an oxidizing agent and a reducing agent.

21. The process to make the flexible superabsorbent binder polymer composition of claim 18 wherein the oxidizing agent is hydrogen peroxide and the reducing agent is sodium erythorbate.

22. The process to make the flexible superabsorbent binder polymer composition of claim 18 wherein the mole ratio of oxidizing agent to the reducing agent is from about 6:

1 to about 2;

1.

23. The process to make the flexible superabsorbent binder polymer composition of claim 18 wherein the polymerization solution is cooled in step e) to from about 20°

C. to about 40°

C.

24. The process to make the flexible superabsorbent binder polymer composition of claim 18 wherein the ethylenically unsaturated monomer containing a trialkoxysilane functional group is methacryloxypropyl trimethoxy silane (MEMO).

25. The process to make the flexible superabsorbent binder polymer composition of claim 18 wherein the low molecular weight polyolefinic glycols is a polyethylene glycol (PEG).

26. A flexible superabsorbent binder polymer composition of claim 18.