SE501325C2 - Process for chlorine-free bleaching of pulp, wherein the pulp is acidified with acetic acid in the treatment with complexing agents - Google Patents
Process for chlorine-free bleaching of pulp, wherein the pulp is acidified with acetic acid in the treatment with complexing agentsInfo
- Publication number
- SE501325C2 SE501325C2 SE9300277A SE9300277A SE501325C2 SE 501325 C2 SE501325 C2 SE 501325C2 SE 9300277 A SE9300277 A SE 9300277A SE 9300277 A SE9300277 A SE 9300277A SE 501325 C2 SE501325 C2 SE 501325C2
- Authority
- SE
- Sweden
- Prior art keywords
- pulp
- peroxide
- acid
- acetic acid
- bleaching
- Prior art date
Links
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 title claims abstract description 42
- 238000004061 bleaching Methods 0.000 title claims abstract description 14
- 238000000034 method Methods 0.000 title claims abstract description 12
- 239000008139 complexing agent Substances 0.000 title claims description 8
- 150000002978 peroxides Chemical class 0.000 claims abstract description 11
- 150000004967 organic peroxy acids Chemical class 0.000 claims abstract description 6
- 239000002253 acid Substances 0.000 claims abstract description 4
- 238000004519 manufacturing process Methods 0.000 claims abstract description 3
- 229920001131 Pulp (paper) Polymers 0.000 claims abstract 3
- KFSLWBXXFJQRDL-UHFFFAOYSA-N Peracetic acid Chemical compound CC(=O)OO KFSLWBXXFJQRDL-UHFFFAOYSA-N 0.000 claims description 20
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 9
- 239000002535 acidifier Substances 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 239000012670 alkaline solution Substances 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- 150000004965 peroxy acids Chemical class 0.000 claims description 2
- CZPZWMPYEINMCF-UHFFFAOYSA-N propaneperoxoic acid Chemical compound CCC(=O)OO CZPZWMPYEINMCF-UHFFFAOYSA-N 0.000 claims description 2
- 239000002657 fibrous material Substances 0.000 claims 1
- 239000003352 sequestering agent Substances 0.000 abstract 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 abstract 1
- 229910052801 chlorine Inorganic materials 0.000 abstract 1
- 239000000460 chlorine Substances 0.000 abstract 1
- 239000000835 fiber Substances 0.000 abstract 1
- 239000000463 material Substances 0.000 abstract 1
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 2
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- VMHLLURERBWHNL-UHFFFAOYSA-M Sodium acetate Chemical compound [Na+].CC([O-])=O VMHLLURERBWHNL-UHFFFAOYSA-M 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- 239000007844 bleaching agent Substances 0.000 description 1
- 239000007853 buffer solution Substances 0.000 description 1
- 230000029087 digestion Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- ZDGGJQMSELMHLK-UHFFFAOYSA-N m-Trifluoromethylhippuric acid Chemical compound OC(=O)CNC(=O)C1=CC=CC(C(F)(F)F)=C1 ZDGGJQMSELMHLK-UHFFFAOYSA-N 0.000 description 1
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 1
- 235000019341 magnesium sulphate Nutrition 0.000 description 1
- 239000001632 sodium acetate Substances 0.000 description 1
- 235000017281 sodium acetate Nutrition 0.000 description 1
- 239000011122 softwood Substances 0.000 description 1
- 229910021653 sulphate ion Inorganic materials 0.000 description 1
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
- D21C9/16—Bleaching ; Apparatus therefor with per compounds
- D21C9/166—Bleaching ; Apparatus therefor with per compounds with peracids
-
- 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
- D21C9/1005—Pretreatment of the pulp, e.g. degassing the pulp
-
- 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
- D21C9/1026—Other features in bleaching processes
- D21C9/1042—Use of chelating agents
-
- 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
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Paper (AREA)
Abstract
Description
501 325 2 10 15 20 25 30 35 bara viskositets- och styrkeegenskaper och med en mark- nadsmässig ljushet av 87-90% ISO. 501 325 2 10 15 20 25 30 35 viscosity and strength properties and with a market brightness of 87-90% ISO.
Sättet enligt uppfinningen kännetecknas av att vid be- handlingen med komplexbildaren surgöres massan med ättiksyra.The method according to the invention is characterized in that during the treatment with the complexing agent the pulp is acidified with acetic acid.
Den inkommande massan är företrädesvis framställd genom en uppslutningsprocess, som ger lågt kappatal, och där- efter underkastad en delignifiering med syrgas så att massan erhåller ett kappatal av omkring 12 eller därunder och en viskositet av minst omkring 1000 dm3/kg.The incoming pulp is preferably produced by a digestion process, which gives a low kappa number, and then subjected to a delignification with oxygen so that the pulp obtains a kappa number of about 12 or less and a viscosity of at least about 1000 dm3 / kg.
Som peroxid användes företrädesvis väteperoxid.As the peroxide, hydrogen peroxide is preferably used.
Det andra bleksteget, som följer efter det första peroxidsteget, utföres med permyrsyra, perättiksyra eller perpropionsyra, företrädesvis perättiksyra, eller en blandning av minst två av dessa.The second bleaching step, which follows the first peroxide step, is carried out with permyric acid, peracetic acid or perpropionic acid, preferably peracetic acid, or a mixture of at least two of these.
Enligt en lämplig utföringsform tillsättes ättiksyra i en sådan mängd att pH-värdet blir under 6, företrädesvis under 5.According to a suitable embodiment, acetic acid is added in such an amount that the pH value becomes below 6, preferably below 5.
Temperaturen i samtliga bleksteg bör vara 80°C eller där- över, företrädesvis 90°C.The temperature in all bleaching steps should be 80 ° C or above, preferably 90 ° C.
Varje peroxidsteg utföres lämpligen i alkalisk lösning.Each peroxide step is conveniently carried out in alkaline solution.
Persyrasteget utföres företrädesvis i sur lösning. Ättiksyra liksom perättiksyra eller andra lämpliga orga- niska persyror tillverkas företrädesvis on-site.The peracid step is preferably carried out in acidic solution. Acetic acid as well as peracetic acid or other suitable organic peracids are preferably produced on-site.
Massans konsistens under de olika behandlingsstegen är omkring 8-16%, företrädesvis 9-11%. 10 15 s 501 325 Följande exempel belyser uppfinningen ytterligare och visar dess oväntade resultat.The consistency of the pulp during the various treatment steps is about 8-16%, preferably 9-11%. 10 15 p. 501 325 The following examples further illustrate the invention and show its unexpected results.
Exempel Ett flertal försök utfördes på en sulfatmassa av barrved, som delignifierats med syrgas och tvättats. Den deligni- fierade massan hade ett kappatal av 12,1, ljushet 33,7% ISO och en viskositet av 1020 dma/kg. Den inmatades i bleklinjen med en konsistens av 10%, som upprätthölls under behandlingen med komplexbildaren EDTA och under alla blekstegen. I försöken 1 och 2 användes svavelsyra som surgörare i Q-steget, medan ättiksyra användes i för- söken 3 och 4 i enlighet med föreliggande uppfinning. 501 325 10 15 20 25 30 35 4 FQr§Ök 1-4 1. Tillsatser Bleksekvens 2. Betingelser PP P QPPQP 3. Resultat l 2 3 4 Qzâlšg 1. EDTA, kg/BDMT 2,0 2,0 HZSO4, kg/BDMT 6,2 - Ättiksyra, kg/BDMT - 15,0 2. Initial-pH 4,7 4,8 Tid, min 60 60 Temp., °C 70 70 1. H202, kg/BDMT 35 35 MgS04, kg/BDMT 3,0 3,0 NaOH, kg/BDMT 25 25 2. Tid, min 240 240 Temp,°C 90 90 Slut-pH 10,9 11,0 3. Förbr. H2O2, kg/BDMT 18 16 Kappatal 5,1 4,9 Viskositet, dmß/kg 910 911 Ljushet, % ISO 77,3 77,0 Eêzâiâg 1. Perättiksyra, räknat som total H2O2, kg/BDMT 20 30 20 30 2. pH, buffertlösning (natriumacetat) 4,3 4,3 4,3 4,3 Tid, min 240 240 240 240 Temp., °C 90 90 90 90 Forts. 10 15 20 25 30 35 5 501 325 1. Tillsatser Bleksekvens 2. Betingelser QPPaP _QEEaB 3. Resultat 1 2 3 4 3. Förbr. perättiksyra som H2O2, kg/BDMT 11,6 17,9 9,9 14,2 Kappatal 1,1 0,7 1,2 0,9 Viskositet, dmfi/kg 842 814 852 841 Ljushet, % ISO 84,4 87,4 84,4 86,8 1. H2O2, kg/BDMT 4,0 4,0 4,0 4,0 MgSO4, kg/BDMT 3,0 3,0 3,0 3,0 Na0H, kg/BDMT 7,0 7,0 7,0 7,0 2. Tid, min 180 180 180 180 Temp., °C 90 90 90 90 Slut-pH 10,3 10,4 10,6 10,5 3. Förbr. H2O2, kg/BDMT 1,5 1,3 0,9 1,1 Kappatal 0,8 0,5 1,1 0,7 Viskositet, dmß/kg 808 778 834 828 Ljushet, % ISO 88,1 89,3 87,8 89,2 Resultaten visar att de enligt exemplen 3 och 4 förbe- handlade och blekta massorna överraskande har signifikant förbättrade viskositeter, vilket i sin tur indikerar förbättrade styrkeegenskaper, i förhållande till de en- ligt exemplen 1 och 2 förbehandlade och blekta massorna.Examples Several experiments were carried out on a sulphate pulp of softwood, which was delignified with oxygen and washed. The delignified pulp had a kappa number of 12.1, brightness 33.7% ISO and a viscosity of 1020 dma / kg. It was fed into the bleach line with a consistency of 10%, which was maintained during the treatment with the complexing agent EDTA and during all the bleaching steps. In Runs 1 and 2, sulfuric acid was used as the acidifier in the Q step, while acetic acid was used in Runs 3 and 4 in accordance with the present invention. 501 325 10 15 20 25 30 35 4 FQr§Ök 1-4 1. Additives Bleaching sequence 2. Conditions PP P QPPQP 3. Result l 2 3 4 Qzâlšg 1. EDTA, kg / BDMT 2.0 2.0 HZSO4, kg / BDMT 6.2 - Acetic acid, kg / BDMT - 15.0 2. Initial pH 4.7 4.8 Time, min 60 60 Temp., ° C 70 70 1. H 2 O 2, kg / BDMT 35 35 MgSO 4, kg / BDMT 3.0 3.0 NaOH, kg / BDMT 25 25 2. Time, min 240 240 Temp, ° C 90 90 Final pH 10.9 11.0 3. Cons. H2O2, kg / BDMT 18 16 Capacity 5.1 4.9 Viscosity, dmß / kg 910 911 Brightness,% ISO 77.3 77.0 Eêzâiâg 1. Peracetic acid, calculated as total H2O2, kg / BDMT 20 30 20 30 2. pH, buffer solution (sodium acetate) 4.3 4.3 4.3 4.3 Time, min 240 240 240 240 Temp., ° C 90 90 90 90 Cont. 10 15 20 25 30 35 5 501 325 1. Additives Bleaching sequence 2. Conditions QPPaP _QEEaB 3. Results 1 2 3 4 3. Cons. peracetic acid as H2O2, kg / BDMT 11.6 17.9 9.9 14.2 Capacity 1.1 0.7 1.2 0.9 Viscosity, dm fi / kg 842 814 852 841 Brightness,% ISO 84.4 87, 4 84.4 86.8 1. H2O2, kg / BDMT 4.0 4.0 4.0 4.0 MgSO4, kg / BDMT 3.0 3.0 3.0 3.0 NaOH, kg / BDMT 7, 0 7.0 7.0 7.0 2. Time, min 180 180 180 180 Temp., ° C 90 90 90 90 Final pH 10.3 10.4 10.6 10.5 3. Cons. H2O2, kg / BDMT 1.5 1.3 0.9 1.1 Capacity 0.8 0.5 1.1 0.7 Viscosity, dmß / kg 808 778 834 828 Brightness,% ISO 88.1 89.3 87 The results show that the pulps pretreated and bleached according to Examples 3 and 4 surprisingly have significantly improved viscosities, which in turn indicates improved strength properties, compared to the pulps pretreated and bleached according to Examples 1 and 2.
Vid lika satsningar av perättiksyra (Pa) i det andra bleksteget, 20 kg i exemplen 1 och 3 och 30 kg i exemplen 2 och 4, ger ättiksyra i stället för svavelsyra som sur- göringsmedel i Q-steget en viskositetsökning med 26 res- pektive 50 enheter.With equal batches of peracetic acid (Pa) in the second bleaching step, 20 kg in examples 1 and 3 and 30 kg in examples 2 and 4, acetic acid instead of sulfuric acid as acidifier in the Q step gives a viscosity increase of 26 50 units.
Såsom nämnts ovan tillverkas ättiksyra liksom perättik- syra eller andra lämpliga organiska persyror företrädes- vis on-site. Vid framställning av massa kan man således 501 325 ur svartluten utvinna bl.a. ättiksyra i en mängd upp till 50 kg per ton massa. Av den utvunna ättiksyran kan t.ex. perättiksyra framställas pà känt sätt. Sättet enligt upp- finningen kan följaktligen genomföras pá ett ekonomiskt 5 mycket fördelaktigt sätt.As mentioned above, acetic acid as well as peracetic acid or other suitable organic peracids are preferably produced on-site. In the production of pulp, 501,325 can thus be extracted from the black liquor, e.g. acetic acid in an amount up to 50 kg per tonne of pulp. Of the extracted acetic acid, e.g. peracetic acid is prepared in a known manner. The method according to the invention can consequently be carried out in an economically very advantageous manner.
Claims (8)
Priority Applications (10)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9300277A SE501325E (en) | 1993-01-29 | 1993-01-29 | Process for chlorine-free bleaching of pulp, wherein the pulp is acidified with acetic acid in the treatment with complexing agents |
| PCT/SE1994/000054 WO1994017239A1 (en) | 1993-01-29 | 1994-01-26 | Method for chlorine-free bleaching of pulp with acetic acid as acidifying agent |
| BR9406193A BR9406193A (en) | 1993-01-29 | 1994-01-26 | Process for bleaching pulp of cellulosic fiber material without the use of chlorine |
| AU59820/94A AU675291B2 (en) | 1993-01-29 | 1994-01-26 | Method for chlorine-free bleaching of pulp with acetic acid as acidifying agent |
| EP94905899A EP0681624A1 (en) | 1993-01-29 | 1994-01-26 | Method for chlorine-free bleaching of pulp with acetic acid as acidifying agent |
| CN 94191058 CN1117301A (en) | 1993-01-29 | 1994-01-26 | Method for chlorine-free bleaching of pulp with acetic acid as acidifying agent |
| CA 2154076 CA2154076A1 (en) | 1993-01-29 | 1994-01-26 | Method for chlorine-free bleaching of pulp with acetic acid as acidifying agent |
| JP6516930A JPH08505907A (en) | 1993-01-29 | 1994-01-26 | Chlorine-free bleaching method for pulp using acetic acid as acidifying agent |
| NO952935A NO305763B1 (en) | 1993-01-29 | 1995-07-24 | Process of chlorine-free bleaching of pulp using acetic acid as an acidifying agent |
| FI953589A FI111387B (en) | 1993-01-29 | 1995-07-27 | Method for chlorine-free bleaching of pulp with acetic acid as an acidifying agent |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9300277A SE501325E (en) | 1993-01-29 | 1993-01-29 | Process for chlorine-free bleaching of pulp, wherein the pulp is acidified with acetic acid in the treatment with complexing agents |
Publications (4)
| Publication Number | Publication Date |
|---|---|
| SE9300277D0 SE9300277D0 (en) | 1993-01-29 |
| SE9300277L SE9300277L (en) | 1994-07-30 |
| SE501325C2 true SE501325C2 (en) | 1995-01-16 |
| SE501325E SE501325E (en) | 1999-09-20 |
Family
ID=20388704
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| SE9300277A SE501325E (en) | 1993-01-29 | 1993-01-29 | Process for chlorine-free bleaching of pulp, wherein the pulp is acidified with acetic acid in the treatment with complexing agents |
Country Status (10)
| Country | Link |
|---|---|
| EP (1) | EP0681624A1 (en) |
| JP (1) | JPH08505907A (en) |
| CN (1) | CN1117301A (en) |
| AU (1) | AU675291B2 (en) |
| BR (1) | BR9406193A (en) |
| CA (1) | CA2154076A1 (en) |
| FI (1) | FI111387B (en) |
| NO (1) | NO305763B1 (en) |
| SE (1) | SE501325E (en) |
| WO (1) | WO1994017239A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1050642C (en) * | 1996-06-25 | 2000-03-22 | 华南理工大学 | Everyday production 30-150 ton high concentration paper pulp bleaching method by using hydrogen peroxide |
| CN103726382B (en) * | 2013-12-31 | 2016-08-17 | 安徽泾县千年古宣宣纸有限公司 | A kind of pure straw Chinese art paper and chloride-free bleaching production process thereof |
| EP3882380B1 (en) * | 2020-03-16 | 2022-04-27 | Re:NewCell AB | One stage method for acid metal removal and bleach |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2219505C3 (en) * | 1972-04-21 | 1974-10-17 | Deutsche Gold- Und Silber-Scheideanstalt Vormals Roessler, 6000 Frankfurt | Chlorine-free multi-stage bleaching of cellulose |
| DE2841013C2 (en) * | 1978-09-21 | 1984-06-07 | Degussa Ag, 6000 Frankfurt | Process for full bleaching of pulp |
| ES2038097T5 (en) * | 1989-06-06 | 2001-05-01 | Eka Chemicals Ab | PROCEDURE FOR WHITENING PAPER PASTES CONTAINING LIGNOCELLULOSE. |
| SE468355B (en) * | 1991-04-30 | 1992-12-21 | Eka Nobel Ab | CHEMISTRY OF CHEMICAL MASS THROUGH TREATMENT WITH COMPLEX PICTURES AND OZONE |
-
1993
- 1993-01-29 SE SE9300277A patent/SE501325E/en not_active IP Right Cessation
-
1994
- 1994-01-26 EP EP94905899A patent/EP0681624A1/en not_active Ceased
- 1994-01-26 JP JP6516930A patent/JPH08505907A/en active Pending
- 1994-01-26 WO PCT/SE1994/000054 patent/WO1994017239A1/en active IP Right Grant
- 1994-01-26 BR BR9406193A patent/BR9406193A/en not_active IP Right Cessation
- 1994-01-26 AU AU59820/94A patent/AU675291B2/en not_active Expired - Fee Related
- 1994-01-26 CN CN 94191058 patent/CN1117301A/en active Pending
- 1994-01-26 CA CA 2154076 patent/CA2154076A1/en not_active Abandoned
-
1995
- 1995-07-24 NO NO952935A patent/NO305763B1/en not_active IP Right Cessation
- 1995-07-27 FI FI953589A patent/FI111387B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| SE501325E (en) | 1999-09-20 |
| BR9406193A (en) | 1996-01-09 |
| CA2154076A1 (en) | 1994-08-04 |
| NO952935L (en) | 1995-09-13 |
| NO952935D0 (en) | 1995-07-24 |
| AU675291B2 (en) | 1997-01-30 |
| FI953589A (en) | 1995-07-27 |
| FI953589A0 (en) | 1995-07-27 |
| AU5982094A (en) | 1994-08-15 |
| NO305763B1 (en) | 1999-07-19 |
| EP0681624A1 (en) | 1995-11-15 |
| JPH08505907A (en) | 1996-06-25 |
| SE9300277D0 (en) | 1993-01-29 |
| CN1117301A (en) | 1996-02-21 |
| WO1994017239A1 (en) | 1994-08-04 |
| FI111387B (en) | 2003-07-15 |
| SE9300277L (en) | 1994-07-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| NUG | Patent has lapsed |