EP0621915A1 - Bleaching of chemical pulp. - Google Patents

Bleaching of chemical pulp.

Info

Publication number
EP0621915A1
EP0621915A1 EP93902618A EP93902618A EP0621915A1 EP 0621915 A1 EP0621915 A1 EP 0621915A1 EP 93902618 A EP93902618 A EP 93902618A EP 93902618 A EP93902618 A EP 93902618A EP 0621915 A1 EP0621915 A1 EP 0621915A1
Authority
EP
European Patent Office
Prior art keywords
pulp
bleaching
complexing agent
consistency
peroxide
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP93902618A
Other languages
German (de)
French (fr)
Other versions
EP0621915B1 (en
Inventor
Lars-Ake Lindstroem
Lars Sjoedin
Solveig Norden
Marten Dahl
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Valmet AB
Original Assignee
Sunds Defibrator AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=20385065&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0621915(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Sunds Defibrator AB filed Critical Sunds Defibrator AB
Publication of EP0621915A1 publication Critical patent/EP0621915A1/en
Application granted granted Critical
Publication of EP0621915B1 publication Critical patent/EP0621915B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/147—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications
    • D21C9/153—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications with ozone
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/1057—Multistage, with compounds cited in more than one sub-group D21C9/10, D21C9/12, D21C9/16
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/147—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/16—Bleaching ; Apparatus therefor with per compounds
    • D21C9/163—Bleaching ; Apparatus therefor with per compounds with peroxides

Definitions

  • This invention relates to the bleaching of sulphate pulp without using bleaching agents containing chlorine.
  • the technique of bleaching chemical pulps is now developing rapidly, because the bleaching chemicals heretofore mainly used, CI 2 , ClO 2, and hypochl-orite, are feared to give rise to products being a risk for the environment and health.
  • Extended digestion with maintained pulp quality can be achieved by impregnating the chips with black liquor in the initial phase of the cook, as described in Finnish patent application 90 0663.
  • This method renders it possible to digest pulp down to a kappa number of about 10 and obtain strength properties equal to or better than with pulp digested to conventional level, kappa number 25-30. Combined with oxygen delignification, kappa numbers as low as 5-6 can be obtained for.further bleaching.
  • the present invention implies, that fully bleached pulp with a brightness above 83% ISO can be made without the use of chlorine-containing bleaching agents.
  • the pulp shall have a kappa number below 9.5. This can be achieved by conventional or extended digestion followed by O 2 -delignification, alternatively by conventional or extended digestion followed by O 2 - and O 3 -delignification.
  • the bleaching is initiated by a pretreatment step with complexing agent followed by treatment with hydroperoxide in alkaline environment in the presence of silicate or an organic complexing agent of the type phosphonic or carboxylic acid.
  • the pulp digested and delignified with oxygen and possibly ozone according to above shall have a kappa number below 9.5. This can be achieved by known methods of digestion and delignification.
  • the pulp shall thereafter be pretreated with complexing agent, for example EDTA or DTPA, at a pulp consistency of 1-15% for 1-60 minutes, preferably 5-30 minutes.
  • the temperature shall be 70-100°C, preferably 80-100°C, and the pH-value 5-7.
  • the pulp thus pretreated is washed and dewatered to a consistency of 18-4.0%, preferably 20-30%.
  • the pH-value is increased to alkaline level, and hydroperoxide is added together with silicate, for example sodium silicate, alternatively together with an organic complexing agent of the type phosphonic or carboxylic acid.
  • the dwell time of the pulp in this hydroperoxide step shall be 1/2 - 5 hours, preferably 1-4 hours, and the temperature 70-100°C, preferably 80-100°C.
  • the silicate charge shall be 2-30 kg/ton pulp, preferably 5-15 kg/ton pulp, expressed as SiO 2 .
  • the charge of the organic complexing agent shall be 0.5-5 kg/ton pulp.
  • Fig. 1 is a diagram, in which the brightness of the pulp is plotted as a function of the pulp consistency at the peroxide bleaching,partly at conventional peroxide bleaching and partly at bleaching according to the invention.
  • the starting pulp was oxygen-delignified coniferous wood sulphate pulp with kappa number 6.5 (10.5 after digestion).
  • Curve 1 showg. conventional peroxide bleaching, with a consumption of H 2 O 2 of 20 kg/ton pulp.
  • Curve 2 and, respectively, 3 refer to bleaching according to the invention with silicate addition and a consumption of H 2 O 2 of 20 and, respectively, 30 kg/ton pulp. It appears from the diagram how the brightness, after bleaching according to the invention and, respectively, after conventional bleaching, depends on the pulp consistency. At about 12% pulp consistency, the brightness obtained is" equal in both cases, but at increased pulp consistency in the peroxide step an increased brightness is obtained according to the invention, while conventional peroxide bleaching results in a deteriorated bright- ness.
  • a coniferous wood sulphate pulp with kappa number 13.3 (digested of Scandinavian fir/pine according to Finnish patent application 90 0663), oxygen delignified to kappa number 8.3 and ozone bleached in acid environment to kappa number 3.2, brightness 61% ISO, intrinsic viscosity 582 dm 3 /kg, was bleached according to the invention.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Detergent Compositions (AREA)

Abstract

A method of bleaching sulphate pulp without using chlorine-containing bleaching agents. The sulphate pulp is oxygen delignified and can possibly also be ozone delignified to a kappa number below 9.5. Thereafter a pretreatment with complexing agent is carried out for 1-60 minutes, at which the pulp consistency is 1-15 %, the temperature 70-110 DEG C and pH 5-7. The pulp thus pretreated is washed and dewatered to a consistency of 18-40 %. Thereafter peroxide bleaching in alkaline environment takes place in the presence of silicate or an organic complexing agent of the type phosphonic or carboxylic acid.

Description

Bleaching of chemical pulp
This invention relates to the bleaching of sulphate pulp without using bleaching agents containing chlorine. The technique of bleaching chemical pulps is now developing rapidly, because the bleaching chemicals heretofore mainly used, CI2, ClO2, and hypochl-orite, are feared to give rise to products being a risk for the environment and health.
Until now, the discussions have been concentrated on the emissions of chlorinated organic substance to the recipient. The majority of the countries in the world have now established limit values for these emissions, which normally are measured as AOX (Adsorbable organic halogens). As a new trend, the customers require to an ever increasing degree paper with a low content of chlorinated organic substance.
Conventional bleaching with Cl2 disappears now more and more, and CI2 is replaced primarily by ClO2. Bleaching with CIO2 causes substantially lower AOX-emissions to the recipient, but the amount of chlorinated substance in the pulp is affected only insignificantly.
In recent years, the use of hydroperoxide at the bleaching of chemical pulps has increased considerably. Hydroperoxide can replace part of the chlorine chemicals.
In patent application SE 89 02058-0, a method is described at which the pulp is pretreated with complexing agent under neutral conditions. By this process, coniferous sulphate pulp can be bleached with peroxide-containing bleaching agents to 70-75% ISO at about 10% pulp consistency. In order to achieve fully bleached pulp qualities., with higher ISO-brightness (above 83% ISO), this process can be combined with final bleaching with CIO2. As a result, th-is final bleaching then yields emission of AOX from the bleach plant and chlorinated organic susbstance in the bleached pulp. Other known methods of reducing emissions of chlorinated organic substance to the recipient are to extend the delignification further in the closed part of the mill, i.e. in the digester house and/or oxygen step.
Extended digestion with maintained pulp quality can be achieved by impregnating the chips with black liquor in the initial phase of the cook, as described in Finnish patent application 90 0663. This method renders it possible to digest pulp down to a kappa number of about 10 and obtain strength properties equal to or better than with pulp digested to conventional level, kappa number 25-30. Combined with oxygen delignification, kappa numbers as low as 5-6 can be obtained for.further bleaching.
By combining conventional digestion, oxygen delignificat- ion and ozone bleaching in acid environment, kappa numbers lower than 10 can be obtained.
It has, however, not been possible to produce fully bleached pulp qualities without final bleaching with ClO2.
The present invention implies, that fully bleached pulp with a brightness above 83% ISO can be made without the use of chlorine-containing bleaching agents.
At the start of the bleaching, the pulp shall have a kappa number below 9.5. This can be achieved by conventional or extended digestion followed by O2-delignification, alternatively by conventional or extended digestion followed by O2- and O3-delignification. The bleaching is initiated by a pretreatment step with complexing agent followed by treatment with hydroperoxide in alkaline environment in the presence of silicate or an organic complexing agent of the type phosphonic or carboxylic acid. The characterizing features of the invention are apparent from the attached claims.
The pulp digested and delignified with oxygen and possibly ozone according to above shall have a kappa number below 9.5. This can be achieved by known methods of digestion and delignification. The pulp shall thereafter be pretreated with complexing agent, for example EDTA or DTPA, at a pulp consistency of 1-15% for 1-60 minutes, preferably 5-30 minutes. The temperature shall be 70-100°C, preferably 80-100°C, and the pH-value 5-7.
The pulp thus pretreated is washed and dewatered to a consistency of 18-4.0%, preferably 20-30%. The pH-value is increased to alkaline level, and hydroperoxide is added together with silicate, for example sodium silicate, alternatively together with an organic complexing agent of the type phosphonic or carboxylic acid. The dwell time of the pulp in this hydroperoxide step shall be 1/2 - 5 hours, preferably 1-4 hours, and the temperature 70-100°C, preferably 80-100°C. The silicate charge shall be 2-30 kg/ton pulp, preferably 5-15 kg/ton pulp, expressed as SiO2.
Alternatively, the charge of the organic complexing agent shall be 0.5-5 kg/ton pulp.
Fig. 1 is a diagram, in which the brightness of the pulp is plotted as a function of the pulp consistency at the peroxide bleaching,partly at conventional peroxide bleaching and partly at bleaching according to the invention.
The starting pulp was oxygen-delignified coniferous wood sulphate pulp with kappa number 6.5 (10.5 after digestion). Curve 1 showg. conventional peroxide bleaching, with a consumption of H2O2 of 20 kg/ton pulp. Curve 2 and, respectively, 3 refer to bleaching according to the invention with silicate addition and a consumption of H2O2 of 20 and, respectively, 30 kg/ton pulp. It appears from the diagram how the brightness, after bleaching according to the invention and, respectively, after conventional bleaching, depends on the pulp consistency. At about 12% pulp consistency, the brightness obtained is" equal in both cases, but at increased pulp consistency in the peroxide step an increased brightness is obtained according to the invention, while conventional peroxide bleaching results in a deteriorated bright- ness.
The following examples have the object to additionally elucidate the invention and its advantages.
Example 1
An oxygen-delignified coniferous wood sulphate pulp
(Scandinavian fir/pine) with kappa number 6.4 (10.5 after digestion according to above Finnish patent application 90 0663), brightness 43% ISO, intrinsic viscosity 605 dur/kg, was pretreated with complexing agent and peroxide bleached according to the invention.
Pretreatment
Pulp consistency % 5
Time min 15
Temperature °C 90
EDTA kg/ton 2
Final pH 6.1
Peroxide step
Pulp consistency % 25
Time min 240
Temperature °C 90
SiO2 kg/ton 10
H2O2 consumption kg/ton 13.5 32.0
Final pH 10.2 10.3
Brightness % ISO 79.6 84.2
Intrinsic viscosity dm3/kg 520 447 Example 2
A coniferous wood sulphate pulp with kappa number 13.3 (digested of Scandinavian fir/pine according to Finnish patent application 90 0663), oxygen delignified to kappa number 8.3 and ozone bleached in acid environment to kappa number 3.2, brightness 61% ISO, intrinsic viscosity 582 dm3/kg, was bleached according to the invention.
Pretreatment as in Example 1
Peroxide bleaching
Pulp consistency % 25
Time min 24.0
Temperature °C 90
SiO2 kg/ton 10
H2O2 consumption kg/ton 7.3 14.2 30.1
Final pH 8.9 9.5 10.1
Brightness % ISO 85.3 88.4 90.4
Intrinsic viscosity dm3/kg 536 498 420
Example 3
An oxygen delignified coniferous wood sulphate pulp
(digested of Pinus taeda according to Finnish patent application 90 0663) with kappa number 9.9, ozone bleached to kappa number 4.8, brightness 54.5% ISO, intrinsic viscosity 607 dm3/kg was pretreated and bleached according to the invention.
Pretreatment as in Example 1
Peroxide bleaching
Pulp consistency % 25
Time min 240
Temperature °C 90
SiO2 kg/ton 10
H2O2 consumption kg/ton 7.9 14.6 29.6
Final pH 10.2 10.4 10.6 Brightness % ISO 81.3 85.3 87.8
Intrinsic viscosity dm3/kg 570 534 459
Example 4
An oxygen delignified birch sulphate pulp with kappa number 9.0, brightness 59.4% ISO and intrinsic viscosity 996 dm3/kg was bleached according to the invention.
Pretreatment as in Example 1
Peroxide bleaching
Pulp consistency % 25
Time min 240
Temperature °C 90
SiO2 kg/ton 10
H2O2 consumption kg/ton 8.5 17.5 35
Final pH 10.2 10.4 10.5
Brightness % ISO 82.2 85.5 86.5
Intrinsic viscosity dm3/kg 903 975 822
The invention is not restricted to the embodiments set forth above , but can be varied within the scope of the invention idea.

Claims

Claims
1. A method of bleaching sulphate pulp without using chlorine-containing bleaching agents, comprising oxygen delignification and possibly ozone delignification of the pulp to a kappa number below 9.5 and subsequent
peroxide bleaching, c h a r a c t e r i z e d i n
that the pulp directly after the delignification is
pretreated with complexing agent for 1-60 minutes,
the pulp consistency being 1-15%, the temperature 70-110°C and pH 5-7, and that the pulp thus pretreated is washed and dewatered to a consistency of 18-40% and thereafter peroxide bleached in alkaline environment in the presence of silicate or an organic. complexing agent of the type phosphonic or carboxylic acid.
2. A method as defined in claim 1, c h a r a c t e r i z e d i n that the peroxide bleaching is carried out for 1/2-5 hours at the temperature 70-110°C.
3. A method as defined in claim 1 or 2, c h a r a c te r i z e d i n that as complexing agent at the
pretreatment EDTA or DTPA is used.
4. A method as defined in any one of the preceding claims, c h a r a c t e r i z e d i n that at the peroxide bleaching silicate is added in an amount of
2-30 kg/ton pulp, expressed as SiO2.
5. A method as defined in any one of the claims 1-3, c h a r a c t e r i z e d i n that at the peroxide bleaching an organic complexing agent of the type phosphonic acid or carboxylic acid is added in an amount of
0.5-5 kg/ton pulp.
6. A method as defined in any one of the preceding claims, c h a r a c t e r i z e d i n that the
bleaching is carried out to a brightness exceeding 83% ISO.
EP93902618A 1992-01-21 1993-01-12 Bleaching of chemical pulp Expired - Lifetime EP0621915B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
SE9200152 1992-01-21
SE9200152A SE469842C (en) 1992-01-21 1992-01-21 Bleaching of chemical pulp with peroxide
PCT/SE1993/000012 WO1993014262A1 (en) 1992-01-21 1993-01-12 Bleaching of chemical pulp

Publications (2)

Publication Number Publication Date
EP0621915A1 true EP0621915A1 (en) 1994-11-02
EP0621915B1 EP0621915B1 (en) 1997-04-16

Family

ID=20385065

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93902618A Expired - Lifetime EP0621915B1 (en) 1992-01-21 1993-01-12 Bleaching of chemical pulp

Country Status (14)

Country Link
EP (1) EP0621915B1 (en)
JP (1) JPH07503042A (en)
AT (1) ATE151826T1 (en)
AU (1) AU653467B2 (en)
BR (1) BR9305761A (en)
CA (1) CA2124088A1 (en)
DE (1) DE69309893T2 (en)
ES (1) ES2102008T3 (en)
FI (1) FI943431A0 (en)
NO (1) NO942718L (en)
NZ (1) NZ246713A (en)
SE (1) SE469842C (en)
WO (1) WO1993014262A1 (en)
ZA (1) ZA93317B (en)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE1004674A3 (en) * 1991-03-11 1993-01-12 Interox Internat Sa Method of laundering of chemical pulp and application of the method of laundering pulp kraft.
BE1006056A3 (en) * 1992-07-06 1994-05-03 Solvay Interox Method of laundering of chemical pulp.
SE501253E8 (en) * 1993-06-08 1994-12-19 Chlorine-free bleaching of chemical pulp
SE9301960L (en) * 1993-06-08 1994-07-25 Kvaerner Pulping Tech Bleaching of chemical pulp with peroxide at overpressure
JPH09502229A (en) * 1993-09-02 1997-03-04 ユニオン キャンプ パテント ホールディング インコーポレイテッド Improved bleaching method for lignocellulosic pulp
BE1007757A3 (en) * 1993-11-10 1995-10-17 Solvay Interox Method of laundering of chemical pulp.
FR2719854B1 (en) * 1994-05-11 1996-06-21 Atochem Elf Sa Process for the preparation of delignified and bleached chemical paper pulps.
SE514697C2 (en) * 1994-08-31 2001-04-02 Valmet Fibertech Ab Elimination of metal ions in pulp bleaching

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8620222D0 (en) * 1986-08-20 1986-10-01 Abitibi Price Inc Peroxide bleaching
US4732650A (en) * 1986-09-15 1988-03-22 The Dow Chemical Company Bleaching of cellulosic pulps using hydrogen peroxide
DE69004492T3 (en) * 1989-06-06 2001-11-15 Eka Nobel Ab Process for bleaching pulps containing lignocellulose.
FI93866B (en) * 1990-02-09 1995-02-28 Sunds Defibrator Rauma Oy Method for preparing sulphate pulp

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9314262A1 *

Also Published As

Publication number Publication date
AU3412593A (en) 1993-08-03
ZA93317B (en) 1993-08-19
SE469842C (en) 1996-01-15
WO1993014262A1 (en) 1993-07-22
DE69309893D1 (en) 1997-05-22
NO942718D0 (en) 1994-07-20
FI943431A (en) 1994-07-20
DE69309893T2 (en) 1997-11-06
SE9200152D0 (en) 1992-01-21
SE9200152L (en) 1993-07-22
CA2124088A1 (en) 1993-07-22
NZ246713A (en) 1995-04-27
BR9305761A (en) 1997-01-28
ATE151826T1 (en) 1997-05-15
ES2102008T3 (en) 1997-07-16
FI943431A0 (en) 1994-07-20
EP0621915B1 (en) 1997-04-16
NO942718L (en) 1994-07-20
AU653467B2 (en) 1994-09-29
JPH07503042A (en) 1995-03-30
SE469842B (en) 1993-09-27

Similar Documents

Publication Publication Date Title
US5785812A (en) Process for treating oxygen delignified pulp using an organic peracid or salt, complexing agent and peroxide bleach sequence
US6258207B1 (en) Alkaline peroxide mechanical pulping of non-woody species
CA2067295C (en) Process for bleaching of lignocellulose-containing material
CA2067296C (en) Process for bleaching of lignocellulose-containing pulp
US6398908B1 (en) Process for acid bleaching of lignocellulose-containing pulp with a magnesium compound
US6007678A (en) Process for delignification of lignocellulose-containing pulp with an organic peracid or salts thereof
US8257550B2 (en) Method of bleaching a pulp
EP0621915B1 (en) Bleaching of chemical pulp
EP0789798B1 (en) Process for delignification and bleaching of chemical wood pulps
AU2003216028B2 (en) Process for bleaching lignocellulose-containing non-wood pulp
NZ577156A (en) Method for bleaching chemical paper pulps by final ozone treatment at high temperature
JPH0672385B2 (en) Bleaching method for lignocellulosic material
EP0670929B2 (en) Process for bleaching of lignocellulose-containing pulp
EP0702735B1 (en) Method of bleaching pulp without using chlorine chemicals
JP3697335B2 (en) Treatment of chemical pulp with acidic bleached white water

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19940514

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT DE ES FR PT SE

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: SUNDS DEFIBRATOR INDUSTRIES AKTIEBOLAG

17Q First examination report despatched

Effective date: 19950320

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE PATENT HAS BEEN GRANTED

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT DE ES FR PT SE

REF Corresponds to:

Ref document number: 151826

Country of ref document: AT

Date of ref document: 19970515

Kind code of ref document: T

REF Corresponds to:

Ref document number: 69309893

Country of ref document: DE

Date of ref document: 19970522

ET Fr: translation filed
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19970716

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2102008

Country of ref document: ES

Kind code of ref document: T3

REG Reference to a national code

Ref country code: PT

Ref legal event code: SC4A

Free format text: AVAILABILITY OF NATIONAL TRANSLATION

Effective date: 19970416

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19980114

Year of fee payment: 6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19980116

Year of fee payment: 6

PLBI Opposition filed

Free format text: ORIGINAL CODE: 0009260

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 19980119

Year of fee payment: 6

26 Opposition filed

Opponent name: KVAERNER PULPING TECHNOLOGIES AB

Effective date: 19980112

PLBG Opposition deemed not to have been filed

Free format text: ORIGINAL CODE: 0009274

26D Opposition deemed not to have been filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: PT

Payment date: 19990107

Year of fee payment: 7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

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

Effective date: 19990112

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 19990125

Year of fee payment: 7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

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

Effective date: 19990930

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

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

Effective date: 19991103

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

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

Effective date: 20000113

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: PT

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

Effective date: 20000731

REG Reference to a national code

Ref country code: PT

Ref legal event code: MM4A

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

Effective date: 20000731

REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20010910