	US 12,258,715 B2
	Method for applying starch to a paper or paperboard web
Kaj Backfolk, Villmanstrand (FI); Isto Heiskanen, Imatra (FI); and Johanna Lyytikainen, Lappeenranta (FI)
Assigned to Stora Enso OYJ, Helsinki (FI)
Appl. No. 17/610,860
Filed by Stora Enso OYJ, Helsinki (FI)
PCT Filed May 13, 2020, PCT No. PCT/IB2020/054505 § 371(c)(1), (2) Date Nov. 12, 2021, PCT Pub. No. WO2020/230035, PCT Pub. Date Nov. 19, 2020.
Claims priority of application No. 1950568-4 (SE), filed on May 14, 2019.
Prior Publication US 2022/0243401 A1, Aug. 4, 2022
Int. Cl. D21H 19/12 (2006.01); D21H 23/48 (2006.01); D21H 23/50 (2006.01); D21J 1/08 (2006.01)

CPC D21H 19/12 (2013.01) [D21H 23/48 (2013.01); D21H 23/50 (2013.01); D21J 1/08 (2013.01)]

15 Claims

1. A method for applying starch to a paper or paperboard web, the method comprising the steps of:

providing an aqueous suspension comprising starch particles and at least 1 wt %, based on a dry solid content of the aqueous suspension, of an amphiphilic polymer, wherein the starch particles are uncooked or partly uncooked starch, wherein the starch particles are not nanofibrillated or microfibrillated cellulose, and wherein the suspension contains less than 1% of a surfactant based on the dry solid content of the suspension,

creating a foam from the aqueous suspension, wherein a solid content of the foamed aqueous suspension is in a range of ≥15 wt % to ≥50 wt %, based on a total weight of 100 wt % of the foamed suspension; and

applying the foam to the paper or paperboard web.