Furnish pretreatment to improve paper strength aid performance in papermaking
The invention is directed towards methods, compositions, and apparatus for increasing the strength of paper made out of a furnish having a large proportion of OCC. The method involves the following steps: 1) Providing a paper furnish having a large amount of OCC in it, 2) adding strength promoter to the furnish prior to adding a strength agent to the furnish, 3) adding a strength agent to the furnish, and 4) making a paper product from the furnish. This method allows cheap OCC material to be used in a papermaking process without the quality problems that the anionic trash in OCC typically causes. Thus paper products having low costs and high quality can be produced.
1. A method of increasing the strength of a paper product comprising:
a. adding a strength promoter to a furnish prior to adding a strength agent to the furnish, wherein the strength promoter comprises an acrylamide/diallyldimethylammonium chloride (“AcAm/DADMAC”) copolymer, the fibers in the furnish comprising at least 10% fibers sourced from old corrugated cardboard,
b. adding a strength agent to the furnish, the strength agent comprising glyoxylated polyacrylamide the dosage ratio of strength promoter relative to strength agent is between 0.1:3 and 0.1:6 wherein the strength agent is dosed relative to the furnish at a dosage of between 3-6 kg/ton, and
c. making a paper product using the furnish according to a papermaking process.
2. The method of claim 1 , wherein the strength promoter is added in an amount of from about 0.01 to about 3 lb/ton of the furnish.
3. The method of claim 1 , wherein the strength promoter has Reduced Specific Viscosity of from about 0.5 to about 15.
4. The method of claim 3 , wherein the strength promoter has Reduced Specific Viscosity of from about 1 to about 12.
5. The method of claim 4 , wherein the strength promoter has Reduced Specific Viscosity of from about 2 to about 8.
6. The method of claim 5 , wherein the strength promoter has Reduced Specific Viscosity of from about 3 to about 6.
7. The method of claim 1 , wherein the furnish further comprises fibers selected from the group consisting of recycled fibers, mechanic fibers, and combinations thereof.
8. The method of claim 1 , wherein the strength agent is a dry strength agent.
9. The method of claim 1 , wherein the strength agent further comprises a compound selected from the group consisting of starch, polyacrylamide, and combinations thereof.
10. The method of claim 1 wherein the fibers in the furnish consist essentially of fibers sourced from old corrugated cardboard.
11. The method of claim 1 , wherein the AcAm/DADMAC copolymer has a weight average molecular weight of from about 800,000 to about 3,000,000 daltons.
12. A method of increasing the strength of a paper product-comprising:
a. adding a strength promoter to a furnish prior to adding a strength agent to the furnish, wherein the strength promoter comprises an acrylamide/diallyldimethylammonium chloride (“AcAm/DADMAC”) copolymer, the fibers in the furnish comprising at least 10% fibers sourced from old corrugated cardboard,
b. adding a strength agent to the furnish, the strength agent comprising glyoxylated polyacrylamide the dosage ratio of strength promoter to strength agent is 0.1:6, the strength agent is dosed relative to the furnish at a dosage of between 3-6 kg/ton, and
c. making a paper product using the furnish according to a papermaking process.