Paper making using hectorite and cationic starch

• US 5,071,512 A
• Filed: 06/24/1988
• Issued: 12/10/1991
• Est. Priority Date: 06/24/1988
• Status: Expired due to Fees

• Current Assignee: Delta Chemical Corporation (DPA Investments, Inc.)
• Original Assignee: Delta Chemical Corporation (DPA Investments, Inc.)
• Inventors: Bixler, Harris J., Peats, Stephen
• Primary Examiner(s): Chin, Peter
• Application Number:
  US07/211,550
• Time in Patent Office: 1,264 Days
• Field of Search: 162/175, 162/181.6, 162/181.5, 162/183
• US Class Current: 162/175
• CPC Class Codes: D21H 17/29 cationic
• CPC Class Codes: D21H 17/68 siliceous, e.g. clays
• CPC Class Codes: D21H 21/10 Retention agents or drainage improvers

Abstract

Addition of hectorite and a cationic starch to the furnish in a paper making operation improves the retention of filler material and the quality of the paper.

Claims

1. A paper making process wherein a collodial sol of a hectorite and a cationic starch having a degree of substitution of at least 0.003 are added separately to a furnish to form a binder consisting essentially of these two materials in said furnish, the weight ratio of starch to hectorite being in the range 0.25:

1 to 15;

1 said hectorite being added in an amount to result in its presence in an amount of at least 2 lbs/ton dry base sheet.

2. A paper making process according to claim 1, wherein said hectorite has a particle size in the range 100-500 nm thickness and 2,500-5,000 nm in width.

3. A paper making process according to claim 1, wherein said cationic starch has a degree of substitution in the range 0.04 to 0.046.

4. A paper making process according to claim 1, wherein said cationic starch is potato starch.

5. A paper making process according to claim 1, wherein said cationic starch and said hectorite is employed in a weight ratio of 1:

1 to 8;

1.

6. A paper making process according to claim 1, wherein said ratio is in the range 1.5:

1 to 6;

1.

7. A paper making process according to claim 1, wherein said hectorite is present in an amount of 2 to 60 lbs/ton dry base sheet.

8. A paper making process according to claim 1, wherein filler is employed in the furnish in an amount of from 100 to 500 lbs/ton dry base sheet.

9. A paper making process according to claim 8, wherein said filler is selected from kaolin, calcium carbonate, talc, titanium dioxide, barium sulfate and calcium sulfate.

10. A paper making process according to claim 1, wherein the furnish and binder are subjected to shear, no greater than 6,000 Pa after addition of the binder.

11. A paper making process according to claim 1, wherein said hectorite and said cationic starch are added to the furnish separately.

12. A paper making process according to claim 8 wherein filler is employed in the furnish in an amount of from 200-300 lbs/ton.

13. A paper making process according to claim 8 wherein the hectorite employed is synthetic or semi-synthetic.