Papermaking process with improved retention and maintained formation
US5571380A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 8, 1992 |
| Grant date | Nov 5, 1996 |
| Priority date | — |
| Expiry date | Jan 8, 2012 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21H21/10
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A process in which paper or paperboard is made by forming an aqueous cellulosic slurry, draining said slurry on a screen to form a sheet and drying said sheet, employs a cationic polymer as a substantially single component retention aid. The cationic polymer has a cationic charge density of at least about 3.2 equivalents of cationic nitrogen per kilogram of dry polymer. The cationic polymer also has an Intrinsic Viscosity of at least about 8 dl/g. The polymer is added to the slurry prior to sheet formation in an amount effective to provide at least about a 50 percent increase in retention without more than about a 10 percent decrease in formation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.