| (19) |
 |
|
(11) |
EP 0 206 560 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
20.07.1988 Bulletin 1988/29 |
| (43) |
Date of publication A2: |
|
30.12.1986 Bulletin 1986/52 |
| (22) |
Date of filing: 30.05.1986 |
|
|
| (84) |
Designated Contracting States: |
|
AT BE DE FR GB SE |
| (30) |
Priority: |
17.06.1985 CA 484110
|
| (71) |
Applicant: Pulp and Paper Research Institute of Canada |
|
() |
|
| (72) |
Inventors: |
|
- Liebergott, Norman
()
- Van Lierop, Barbara
()
|
|
| |
|
| (54) |
Alkaline-peroxide-oxygen treatment for unbleached and chlorinated chemical pulps |
(57) There are provided improvements relating to the delignification and/or the bleaching
of a chemical pulp wherein the cellulosic material is simultaneously treated with
an alkali compound, a peroxygen compound and an oxygen gas at partial pressure in
the presence of a viscosity protecting catalyst.