Method for bleaching paper pulp with organic peracids followed by peroxide and sodium hydroxide
US6866749B2 · kind B2 · utility
34Cited by
3References
14Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 14, 2001 |
| Grant date | Mar 15, 2005 |
| Priority date | — |
| Expiry date | Sep 14, 2021 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C9/163
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The invention concerns a method for bleaching different types of paper pulp in two steps at atmospheric pressure and at a temperature not higher than 100 DEG C. The first step consists in contacting the unbleached paste with a mixture of paracetic acid and performic acid. The second step consists in treating the bleached pulp derived from the first step, with a solution of soda and hydrogen peroxide. The resulting pulps exhibit a high index of whiteness and a degree of polymerisation close to unbleached pulps. The method is environmentally safe and non-polluting.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.