Cationic cross-linked starch for wet-end use in papermaking

• US 5,122,231 A
• Filed: 06/08/1990
• Issued: 06/16/1992
• Est. Priority Date: 06/08/1990
• Status: Expired due to Term

• Current Assignee: Cargill Incorporated
• Original Assignee: Cargill Incorporated
• Inventors: Anderson, Kevin R.
• Primary Examiner(s): Chin, Peter
• Application Number:
  US07/534,945
• Time in Patent Office: 739 Days
• Field of Search: 162/175, 162/183, 536/106
• US Class Current: 162/175
• CPC Class Codes: D21H 17/00 Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
• CPC Class Codes: D21H 17/29 cationic

Abstract

A new cationized subsequently cross-linked starch is described in connection with improved method of paper making in the wet-end system of a paper machine utilizing a Neutral or Alkaline furnish.

Claims

1. In a papermaking process having a pH of about 6 or greater, a method to increase starch loading capacity, the method comprising:

adding cationized cross-linked starch to a paper furnish of the process prior to the conversion of the furnish to a dry web wherein the starch is cationized to a degree of substitution on the hydroxyl groups of the starch between about 0.005 and about 0.050 and wherein after the cationization the starch is cross-linked to a hot paste viscosity in the range of from about 500 cps to about 3000 cps as measured on a Brookfield viscometer at about 95°

C. using a No. 21 spindle.

2. In a process as recited in claim 1 wherein the cationized cross-linked starch is added into a paper furnish is the process at a level sufficient to provide a Zeta potential of about zero in the furnish.

3. In a process as recited in claim 1 wherein the cationized cross-linked starch is added into a paper furnish in the process to at least about 20 pounds of starch per ton of fiber in the furnish.

4. In a process as recited in claims 1, 2 or 3 wherein the cationized cross-linked starch is cationized to a degree of substitution of between about 0.030 to about 0.040.

5. In a process as recited in claims 1, 2 or 3 wherein the starch is cross-linked with a cross-linker selected from the group consisting of a polyamine polyepoxide resin, 1,4 butanediol diglycidyl ether, phosphorousoxychloride, and mixtures thereof.

6. In a process as recited in claim 1, 2 or 3 wherein the starch is cationized by reacting it with a quaternary ammonium ion.

7. In a process as recited in claim 5 wherein the starch is cationized by reacting it with a quaternary ammonium ion.

8. In a papermaking process having a pH of about 6 or greater, a method to increase starch loading capacity, the method comprising:

adding cationized cross-linked starch to a paper furnish of the process in an amount effective for making Zeta potential of the furnish about zero and wherein the starch is cationized with monovalent cations and has a degree of substitution of monovalent cations on the hydroxyl groups of the starch between about 0.005 and about 0.050 and wherein after cationization the starch is cross-linked to a hot paste viscosity in the range of from about 500 cps to about 3000 cps as measured on a Brookfield viscometer at about 95°

C. using a No. 21 spindle.

9. In a process as recited in claim 8 wherein the cross-linked starch is loaded into the paper furnish in the process to at least about 20 pounds of starch per ton of fiber in the furnish.

10. In a process as recited in claims 8 or 9 wherein the cationized cross-linked starch is cationized to a degree of substitution of between about 0.030 to about 0.040.

11. In a process as recited in claims 8 or 9 wherein the starch is cross-linked with a cross-linker selected from the group consisting of a polyamine polyepoxide resin, 1, 4 butanediol diglycidyl ether, phosphorousoxychloride, and mixtures thereof.

12. In a process as recited in claim 10 the starch is cross-linked with a cross-linker selected from the group consisting of a polyamine polyepoxide resin, 1,4 butanediol diglycidyl ether, phosphorousoxychloride, and mixtures thereof.

13. In a process as recited in claims 8 or 9 wherein the starch is cationized by reacting it with a quaternary ammonium ion.

14. In a process as recited in claim 12 wherein the starch is cationized by reacting it with a quaternary ammonium ion.