EP 1790771 A1 20070530 - PULP BLEACHING PROCESSES
Title (en)
PULP BLEACHING PROCESSES
Title (de)
ZELLSTOFFBLEICHVERFAHREN
Title (fr)
MÉTHODE POUR BLANCHIR DE LA PÂTE
Publication
Application
Priority
- JP 2005010521 W 20050608
- JP 2004169367 A 20040608
- JP 2004289267 A 20040930
- JP 2005102615 A 20050331
- JP 2005102558 A 20050331
Abstract (en)
The present invention aims to further advance the acid treatment or irradiation technology for pulp to develop a bleaching process using smaller amounts of chlorine chemicals with higher efficiency as compared with conventional bleaching processes. It also aims to provide an excellent high brightness pulp having a low environmental impact and no discoloration as well as a paper containing it. The present invention provides a chlorine-free bleaching process with very high efficiency by irradiating a pulp washed after an acid treatment with UV light and/or visible light at a wavelength of 100 - 400 nm under alkaline conditions, preferably in a pH range of 10 - 13. The acid treatment can be performed under conditions of pH 1 - 6 and a temperature of 80°C or more. The irradiation treatment can be performed in the presence of at least one compound selected from the group consisting of reducing agents, peroxides, and hydrogen-donating organic compounds. The present invention also provides a high brightness chemical pulp having an ISO brightness of 88% or more and a brightness loss of 1.0% or less in a specific fading test.
IPC 8 full level
CPC (source: EP US)
D21C 9/1005 (2013.01 - EP US); D21C 9/1084 (2013.01 - EP US); D21C 9/16 (2013.01 - EP US)
Designated contracting state (EPC)
FI SE
DOCDB simple family (publication)
EP 1790771 A1 20070530; EP 1790771 A4 20121003; CA 2569848 A1 20051222; CA 2569848 C 20110510; US 2007246176 A1 20071025; WO 2005121442 A1 20051222
DOCDB simple family (application)
EP 05748560 A 20050608; CA 2569848 A 20050608; JP 2005010521 W 20050608; US 62896105 A 20050608