Global Patent Index - EP 0797703 B1

EP 0797703 B1 2000-02-09 - PEROXIDE BLEACHING PROCESS FOR CELLULOSIC AND LIGNOCELLULOSIC MATERIAL

Title (en)

PEROXIDE BLEACHING PROCESS FOR CELLULOSIC AND LIGNOCELLULOSIC MATERIAL

Title (de)

VERFAHREN ZUM PEROXIDBLEICHEN VON CELLULOSISCHEN UND LIGNOCELLULOSISCHEN MATERIALEN

Title (fr)

PROCEDE DE BLANCHIMENT AU PEROXYDE DE SUBSTANCES CELLULOSIQUES ET LIGNOCELLULOSIQUES

Publication

EP 0797703 B1 (EN)

Application

EP 95926123 A

Priority

  • US 9508137 W
  • US 27353994 A

Abstract (en)

[origin: WO9601920A1] A method for bleaching cellulosic and lignocellulosic pulp using hydrogen peroxide as a bleaching reagent, utilizes a two-step reaction, viz. a short high temperature step at a pressure sufficient to suppress boiling and a longer atmospheric pressure reduced temperature step to consume a substantial portion of the hydrogen peroxide remaining after the short phase. The method includes the steps of introducing pulp (15), at a consistency of 10 %-18 %, to a mixer (100) in which the pulp is heated to a temperature above 100 DEG C; adding sufficient sodium hydroxide to bring the pulp to a pH of 8.5; adding sufficient hydrogen peroxide (36) to equal from about 0.5 %-5.0 %, by weight, of the pulp; passing the pulp through a pressurized reactor column (400) at a rate providing a reaction time in the column of between 1 and 30 minutes; and depositing the pulp in a reaction tower and allowing the reaction to proceed for 1-5 hours until a substantial portion of the residual hydrogen peroxide has been consumed. It may be desirable to introduce the pulp to a mixer and add alkali to reactivate residual hydrogen peroxide by bringing the pulp to a pH of at least 9 between bleaching steps.

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

D21C 9/16; D06L 3/02; D21C 9/10

IPC 8 full level (invention and additional information)

D21C 9/10 (2006.01); D21C 9/153 (2006.01); D21C 9/16 (2006.01)

CPC (invention and additional information)

D21C 9/1026 (2013.01); D21C 9/1057 (2013.01); D21C 9/163 (2013.01)

Designated contracting state (EPC)

AT DE ES PT SE

EPO simple patent family

WO 9601920 A1 19960125; AT 189716 T 20000215; BR 9508388 A 19980714; CA 2194880 A1 19960125; CN 1176673 A 19980318; DE 69515066 D1 20000316; DE 69515066 T2 20010419; DE 797703 T1 19980219; EP 0797703 A1 19971001; EP 0797703 B1 20000209; EP 0919661 A1 19990602; ES 2107399 T1 19971201; ES 2107399 T3 20000701; FI 970104 A0 19970110; FI 970104 A 19970310; JP 2787618 B2 19980820; JP H09508945 A 19970909; PT 797703 E 20000731; RU 2141016 C1 19991110; ZA 9505290 B 19961227

INPADOC legal status


2003-08-29 [REG PT MF4A] REVOCATION OF NATIONAL PROTECTION

- Effective date: 20030616

2003-06-11 [27W] REVOKED

- Effective date: 20030124

2003-04-16 [REG ES FD2A] ANNOUNCEMENT OF LAPSE IN SPAIN

- Effective date: 20030303

2003-02-04 [EUG] SE: EUROPEAN PATENT HAS LAPSED

2002-06-30 [PG25 SE] LAPSED IN A CONTRACTING STATE ANNOUNCED VIA POSTGRANT INFORM. FROM NAT. OFFICE TO EPO

- Ref Country Code: SE

- Free text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

- Effective date: 20020630

2002-04-29 [REG PT MM4A] ANNULMENT/LAPSE DUE TO NON-PAYMENT OF FEES, SEARCHED AND EXAMINED PATENT

- Free text: LAPSE DUE TO NON-PAYMENT OF FEES

- Effective date: 20011231

2002-04-03 [PG25 DE] LAPSED IN A CONTRACTING STATE ANNOUNCED VIA POSTGRANT INFORM. FROM NAT. OFFICE TO EPO

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2001-12-31 [PG25 PT] LAPSED IN A CONTRACTING STATE ANNOUNCED VIA POSTGRANT INFORM. FROM NAT. OFFICE TO EPO

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- Free text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

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2001-06-30 [PG25 ES] LAPSED IN A CONTRACTING STATE ANNOUNCED VIA POSTGRANT INFORM. FROM NAT. OFFICE TO EPO

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2001-06-29 [PG25 AT] LAPSED IN A CONTRACTING STATE ANNOUNCED VIA POSTGRANT INFORM. FROM NAT. OFFICE TO EPO

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- Free text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

- Effective date: 20010629

2001-05-31 [PGFP SE] POSTGRANT: ANNUAL FEES PAID TO NATIONAL OFFICE

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- Payment date: 20010531

- Year of fee payment: 7

2000-12-27 [26] OPPOSITION FILED

- Opponent name: KVAERNER PULPING TECHNOLOGIES AB

- Effective date: 20001102

2000-07-31 [REG PT SC4A] TRANSLATION IS AVAILABLE

- Free text: AVAILABILITY OF NATIONAL TRANSLATION

- Effective date: 20000508

2000-07-07 [EN] FR: TRANSLATION NOT FILED

2000-07-01 [REG ES FG2A] DEFINITIVE PROTECTION

- Document: ES 2107399 T3

2000-06-22 [PGFP ES] POSTGRANT: ANNUAL FEES PAID TO NATIONAL OFFICE

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2000-05-26 [PGFP DE] POSTGRANT: ANNUAL FEES PAID TO NATIONAL OFFICE

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2000-05-23 [PGFP AT] POSTGRANT: ANNUAL FEES PAID TO NATIONAL OFFICE

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2000-05-19 [PGFP PT] POSTGRANT: ANNUAL FEES PAID TO NATIONAL OFFICE

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2000-03-16 [REF] CORRESPONDS TO:

- Document: DE 69515066 20000316

2000-02-09 [AK] DESIGNATED CONTRACTING STATES:

- Kind Code of Ref Document: B1

- Designated State(s): AT DE ES PT SE

2000-02-09 [REF] CORRESPONDS TO:

- Document: AT 189716 T 20000215

1998-02-19 [DET] DE: TRANSLATION OF PATENT CLAIMS

1997-12-17 [17Q] FIRST EXAMINATION REPORT

- Effective date: 19971031

1997-12-15 [TCAT] AT: TRANSLATION OF PATENT CLAIMS FILED

1997-12-01 [REG ES BA2A] PROVISIONAL PROTECTION

- Document: ES 2107399 T1

1997-10-01 [17P] REQUEST FOR EXAMINATION FILED

- Effective date: 19970110

1997-10-01 [AK] DESIGNATED CONTRACTING STATES:

- Kind Code of Ref Document: A1

- Designated State(s): AT DE ES PT SE