Process for bleaching organic peroxyacid cooked material with an alkaline solution of hydrogen peroxide
US4793898A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 17, 1986 |
| Grant date | Dec 27, 1988 |
| Priority date | — |
| Expiry date | Nov 17, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W10/10
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A lignocellulosic raw material is pulped with a cooking liquor containing organic peroxyacids, such as peroxyformic acid or peroxyacetic acid, and the defibered pulp is bleached with an alkaline solution containing hydrogen peroxide, the pH of which is at least 10 in the beginning of the treatment, and which is provided by adding to a sodium hydroxide solution, hydrogen peroxide in an amount which if calculated as a percent of the dry weight of the material coming to the treatment corresponds to from 0.20 to 0.80, preferably from 0.25 to 0.70 and most preferably from 0.45 to 0.65 times the kappa number of the pulp obtained from the previous stage of the process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.