Global Patent Index - EP 1036237 A1

EP 1036237 A1 2000-09-20 - IMPROVEMENTS TO THE BLEACHING PROCESS FOR CHEMICAL PULP AND INTERMEDIATE PULP DISPERSIONS

Title (en)

IMPROVEMENTS TO THE BLEACHING PROCESS FOR CHEMICAL PULP AND INTERMEDIATE PULP DISPERSIONS

Title (de)

BLEICHVERFAHREN FÜR CHEMISCHE PULPE UND FÜR PULPENDISPERSIONEN IN FORM EINES ZWISCHENPRODUKTES

Title (fr)

PERFECTIONNEMENTS APPORTES AU PROCEDE DE BLANCHIMENT DE LA PATE CHIMIQUE ET DISPERSIONS INTERMEDIAIRES DE PATE

Publication

EP 1036237 A1 (EN)

Application

EP 97952831 A

Priority

EP 9706696 W

Abstract (en)

[origin: WO9927178A1] The invention relates to a process for bleaching chemical pulp, comprising a alkaline oxygen delignification step and a subsequent hydrogen peroxide bleaching step and involving removal of undesirable metal ions before and/or during the peroxide bleaching step by means of a chelating agent, wherein a polyamino disuccinic acid derivative, preferably ethylenediamine disuccinate (EDDS), is used as chelating agent at a pH value above 9.5, preferably at a pH value ranging from 10 to 11. The invention also relates to intermediate pulp dispersions containing a polyamino disuccinic acid derivative, preferably ethylenediamine disuccinate (EDDS), in a concentration of 0.01 to 2.5 % w/w on dry pulp substance and at a pH value above 9.5.

IPC 1-7 (main, further and additional classification)

D21C 9/10

IPC 8 full level (invention and additional information)

D21C 9/10 (2006.01)

CPC (invention and additional information)

D21C 9/1042 (2013.01)

Citation (search report)

See references of WO 9927178A1

Designated contracting state (EPC)

AT BE CH DE DK ES FI FR GB GR IE IT LI NL PT SE

EPO simple patent family

WO 9927178 A1 19990603; AU 5657098 A 19990615; CA 2310278 A1 19990603; EP 1036237 A1 20000920

INPADOC legal status


2002-05-15 [18R] REFUSED

- Effective date: 20011218

2000-12-13 [RAP1] TRANSFER OF RIGHTS OF AN EP PUBLISHED APPLICATION

- Owner name: AMYLUM EUROPE N.V.

2000-11-15 [17Q] FIRST EXAMINATION REPORT

- Effective date: 20000927

2000-09-20 [17P] REQUEST FOR EXAMINATION FILED

- Effective date: 20000417

2000-09-20 [AK] DESIGNATED CONTRACTING STATES:

- Kind Code of Ref Document: A1

- Designated State(s): AT BE CH DE DK ES FI FR GB GR IE IT LI NL PT SE