WO1997030208A1 - Process for the treatment of chemical pulp - Google Patents
Process for the treatment of chemical pulp Download PDFInfo
- Publication number
- WO1997030208A1 WO1997030208A1 PCT/FI1997/000106 FI9700106W WO9730208A1 WO 1997030208 A1 WO1997030208 A1 WO 1997030208A1 FI 9700106 W FI9700106 W FI 9700106W WO 9730208 A1 WO9730208 A1 WO 9730208A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- bleaching
- pulp
- process according
- acid
- chelating
- Prior art date
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
- D21C9/16—Bleaching ; Apparatus therefor with per compounds
-
- 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
Definitions
- the invention relates to a process for the bleaching or de- lignification of pulp, wherein, before bleaching or delignifi- cation with an oxygen chemical, the pulp is pretreated with a chelating agent in order to eliminate the adverse effects of any heavy metals present in the pulp.
- ECF elementary chlorine free
- TCF total chlorine free
- Usable bleaching processes also include bleaching with peroxy compounds (such as peracetic acid, caron acid, or mixtures of peracids), a peroxide-enhanced oxygen step, and a peroxide-enhanced oxygen-alkali step.
- peroxy compounds such as peracetic acid, caron acid, or mixtures of peracids
- Such bleaching steps are most commonly preceded by the binding of heavy metals.
- the metals can be removed by an acid wash. This is often disadvantageous, since at least some of the sub ⁇ sequent bleaching steps are carried out in alkaline conditions. If heavy metals are removed at a low pH, it is necessary first to use an acid in order to reach a low pH and in the next step an alkali to neutralize the acid. Furthermore, the acid wash removes Mg and Ca ions, which are regarded as advantageous for bleaching. The acid wash may also reduce the strength of the pulp.
- Peroxy compounds such as peracetic acid and hydrogen peroxide are highly susceptible to the catalytic action of heavy metals.
- the applicant's WO application publications 95/35406, 95/35407 and 95/35408 describe transition-metal activated bleaching with peroxy compounds in acid conditions. The success of the bleaching presupposes the binding of heavy metals before the bleaching and/or during the bleaching.
- heavy metals are bound by using agents which chelate metal ions, for example poly- aminocarboxylic acids. These include in particular ethylene diamine tetra-acetic acid and its salts (EDTA) and diethylene triamine penta-acetic acid and its salts (DTPA).
- EDTA ethylene diamine tetra-acetic acid and its salts
- DTPA diethylene triamine penta-acetic acid and its salts
- the ions the most detrimental in terms of bleaching are manganese (Mn), iron (Fe) and copper (Cu).
- other heavy metals, such as chromium ions (Cr), etc. have a detrimental effect, both on the con ⁇ sumption of peroxy compounds and often on the bleaching result, by reducing, for example, the viscosity of the bleached pulp. Detrimental heavy metals originate in the pulp, the treatment waters and the pulp-treatment apparatus.
- Effective chelating agents are often poorly biodegradable, as is DTPA, or are completely non-biodegradable, as is EDTA.
- TCF bleaching has increased the use of the said chelating agents. Therefore interest has arisen in replacing poorly biodegradable chelating agents either in part or entire ⁇ ly with biodegradable chelating agents.
- the bio ⁇ degradable chelating agents be preferably phosphorus-free and also contain as small an amount of nitrogen as possible.
- Biodegradable complexing agents have been developed for deter ⁇ gent builders. They must at the same time have softening action on water, i.e. they must bind calcium ions and magnesium ions.
- One such sequestering agent is ethylenediamine disuccinic acid (EDDS). This compound has three stereoisomers.
- EP patent application 556 782 discloses the use of EDDS as an iron complexer in photography chemicals.
- Example 9 of the pub ⁇ lication mentions that the ferric salts of EDTA, DTPA and HEDTA are not biodegradable.
- the Fe 7 + salt of EDDS is biodegradable. The biodegradabilities of the compounds were tested in the example by a generally approved testing method
- Another known biodegradable complexing agent is 2,2'-imino ⁇ disuccinic acid (ISA).
- ISA 2,2'-imino ⁇ disuccinic acid
- the use of this compound in alkaline detergents is disclosed in EP patent application 509 382.
- the patent application mentions the use of 2,2'-iminodisuccinic acid as a stabilizer of peroxide compounds, in particular in alkaline detergent compositions which contain hydrogen peroxide and its derivatives.
- only perborate is used. Since perborate releases hydrogen peroxide only slowly, no far-reaching conclusions can be drawn from the examples of the patent regarding the stabilization of hydrogen peroxide in similar detergent compositions.
- DE patent application 4 216 363 discloses the use of ISA as a stabilizer of tensides. There is no mention of the use of a peroxide compound.
- EP patent application 513 948 mentions the use of the substance in detergents which are intended for hard surfaces and contain an organic solvent boiling at approx. 90 °C. There is no mention of the use of a peroxide compound.
- DE patent application 4 340 043 discloses the use of ISA as a bleaching agent in the bleaching of groundwood pulp.
- the purpose of ISA is the stabilization of hydrogen peroxide, and the examples show that at a pH of 10 it is a better stabilizer than DTPA.
- the object of the present invention is to eliminate the adverse effects of heavy metals in the bleaching and delignification of chemical pulp. It is also an object to obtain a biodegradable effective chelating agent which yields a good bleaching result.
- n 1-3 m is 0-3 p is 1-3
- R , R 2 3 and R 4 are H, Na, K, Ca or Mg
- R 5 and R 6 are H, CH 2 OH, CH 2 CH 2 OH or
- DTPA which is commonly used in the bleaching of pulp, chelates heavy metals best at a pH of approx. 5.
- Suitable pH values in the use of the compounds in accordance with the in ⁇ vention for the pretreatment of pulp are pH 4-8, preferably pH 5.0-7.5 and most preferably pH 6.5-7.5. If the compounds are also used in the actual bleaching or delignification step, the suitable pH values are respectively pH 4-8, preferably pH 4-6 and most preferably pH 4-5. Since chelating can be carried out at a higher pH value, the consumption of alkali in the sub ⁇ sequent step is not as high as when the chelating is carried out at a lower pH. This is a clear advantage over, for example,
- the process according to the invention can be used for all known chemical pulps. These include alkaline and neutral sul- fite pulps, soda pulps, sulfate pulps (kraft pulps) and oxygen- delignified (oxygen cooking) sulfate pulps. Furthermore, the process can be used in the bleaching of so-called organosolv pulps in which alcohols or organic acids have been used as the cooking solvent, for example Milox cooking in formic acid.
- the chelating process according to the invention may also be used when polysulfides or, for example, anthraquinone, have/has been used in sulfate cooking.
- the treatment can be carried out on pulp cooked from different fiber raw materials, such as softwood, hardwood or reed, straw or other raw material of vegetable origin.
- the chelating process according to the invention with compounds of Formula I is used as a pretreatment before bleaching or delignification with oxygen chemicals.
- Chelating agents according to Formula I such as EDDS and ISA, can also be used as a chelating agent in bleaching or delig ⁇ nification with oxygen chemicals.
- bleaching with peracetic acid bleaching with mixtures of peracids, bleaching with hydrogen peroxide, bleaching with mixtures of hydrogen peroxide and peracids, transition-metal catalyzed hydrogen peroxide bleaching within the acid pH range, developed by the applicant, alkaline peroxide bleaching, and combinations of all these, as well as oxygen delignification, peroxide-enhanced oxygen-alkali steps and pressurized peroxide steps and, in conjunction with these, optional treatments with enzymes, ozone or chlorine dioxide.
- the chelating process according to the invention can be used as a pretreatment for pulp bleaching or delignification in acid conditions and possibly also in the bleaching or delignifica ⁇ tion step itself.
- the pH control of an acid chelating step can be carried out using conventional mineral acids, such as sulfuric acid, sulfur dioxide or an aqueous solution thereof, carbon dioxide, or organic acids such as formic acid and acetic acid.
- mineral acids such as sulfuric acid, sulfur dioxide or an aqueous solution thereof, carbon dioxide, or organic acids such as formic acid and acetic acid.
- an especially suit ⁇ able chelating agent according to Formula I may be ethylenedi- amine-N,N' -disuccinic acid, its various isomers and its alkali metal salts, such as sodium and potassium salts, and its earth- alkali metal salts, such as calcium and magnesium salts. It is also possible to use ethylenediamine-N,N'-disuccinic acid to ⁇ gether with calcium sulfate and/or magnesium sulfate.
- Another particularly suitable chelating agent is 2,2'-iminodisuccinic acid, its various isomers and its alkali metal salts, such as sodium and potassium salts, and its earth-alkali metal salts, such as calcium and magnesium salts. It is also possible to use 2,2'-iminodisuccinic acid together with calcium sulfate and/or magnesium sulfate.
- Usable chelating agents also include N-(l,2-dicarboxyethyl)-N- (2-hydroxyethyl)aspartamic acid, its various isomers and its alkali metal salts and earth-alkali metal salts.
- the acid may also be used together with potassium sulfate or magnesium sulfate.
- the chelating agent may be added in an amount of 0.1-5 kg, preferably 0.5-2 kg per metric ton of dry pulp.
- EDDS and ISA can be used to ⁇ gether with hydroxycarboxylic acids without the bleaching result being worsened.
- EDDS and ISA may in part be replaced with chelating agents which do not contain nitrogen, such as hydroxycarboxylic acids having the general formula II
- n 1-8, m is 0-2n, p is 0-n, q is 0-2,
- R- ⁇ is COOH
- R 2 is H, CH 2 OH or COOH.
- carboxylic acids, hydroxy ⁇ carboxylic acids, polyhydroxycarboxylic acids and hydroxypoly- carboxylic acids according to Formula II such as citric acid, tartaric acid, lactic acid, pimelic acid, glutamic acid, gluco- heptonic acid, ascorbic acid, glycolic acid, glutaric acid, adipic acid, succinic acid or alonic acid, can be used as replacement chelating agents.
- hydroxy acids can be used as chel ⁇ ating agents in bleaching.
- the said substances are quite poor binders of heavy metals, but bind well calcium and magnesium.
- citric acid has been used as a replacement for phos ⁇ phates in phosphate-free detergents and cleansing agents, in which the substances are required to bind calcium and mag ⁇ nesium.
- Especially the binding of magnesium should be dis ⁇ advantageous in terms of bleaching.
- CS stands for consistency
- PAA for a peracetic acid treatment
- mP for a olybdate-activated peroxide treatment
- O for an oxygen treat ⁇ ment
- P for an alkaline peroxide treatment
- chelat ⁇ ing step The doses in the tables are indicated in kilograms per metric ton of pulp (kg/tp).
- Na ⁇ DTPA stands for the pentasodium salt of DTPA
- Na ⁇ EDTA stands for the tetrasodium salt of EDTA
- H4EDDS stands for the acid form of EDDS.
- the pH used will determine how the chelating agents are dissociated, i.e. in which form they actually appear in the treatment.
- the H ⁇ EDDS (reaction mixture) mentioned in the table refers to experiments in which the chelating agent used was an unpurified reaction product directly from the process for the preparation of EDDS.
- Table 2 shows the results of washing experiments similar to those described in Example 1, when EDDS was diluted with cer ⁇ tain hydroxy acids.
- DTPA is usually dosed into a softwood pulp at a rate of approx. 2 kg/tp.
- Table 2 the effect of the DTPA dose on the chelating of metals was first investigated. Chelating was clearly less when the dose of EDDS was reduced from a rate of 2.0 kg/tp to a rate of 1.0 kg/tp or 0.5 kg/tp. In the previous series of experiments (Table 1) it was observed that when Na ⁇ EDDS was used at a rate of 1.5 kg/tp, chelating was as com ⁇ plete as when Na 5 DTPA was used at a rate of 2.0 kg/tp.
- the nitrogen load in the effluents from the chelating step can be reduced significantly, while the chelating of the metals is still sufficiently com ⁇ plete for bleaching.
- Na ⁇ DTPA stands for the pentasodium salt of DTPA
- Na ⁇ EDTA stands for the tetrasodium salt of EDTA
- ISA stands for the acid form of iminodisuccinic acid of ISA.
- pH used that determines how the chelating agents are is the pH used that determines how the chelating agents are dissociated, i.e. in which form they actually are present in the treatment.
- Chelating with a mixture of ISA and the sodium salt of citric acid was also successful, considering that the chelating was carried out at a pH of 7.7.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE69725558T DE69725558T2 (en) | 1996-02-19 | 1997-02-19 | METHOD FOR TREATING CHEMICAL CELLULAR |
AU17973/97A AU1797397A (en) | 1996-02-19 | 1997-02-19 | Process for the treatment of chemical pulp |
AT97903408T ATE252176T1 (en) | 1996-02-19 | 1997-02-19 | METHOD FOR TREATING CHEMICAL PULP |
EP97903408A EP0882151B1 (en) | 1996-02-19 | 1997-02-19 | Process for the treatment of chemical pulp |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI960756 | 1996-02-19 | ||
FI960756A FI115469B (en) | 1996-02-19 | 1996-02-19 | Process for the treatment of chemical cellulose material |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1997030208A1 true WO1997030208A1 (en) | 1997-08-21 |
Family
ID=8545485
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FI1997/000106 WO1997030208A1 (en) | 1996-02-19 | 1997-02-19 | Process for the treatment of chemical pulp |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0882151B1 (en) |
AT (1) | ATE252176T1 (en) |
AU (1) | AU1797397A (en) |
DE (1) | DE69725558T2 (en) |
FI (1) | FI115469B (en) |
WO (1) | WO1997030208A1 (en) |
Cited By (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1998004775A1 (en) * | 1996-07-26 | 1998-02-05 | Basf Aktiengesellschaft | Use of complexing agents for cellulose and wood bleaching, paper production and used paper deinking |
WO1999027178A1 (en) * | 1997-11-25 | 1999-06-03 | Amylum Belgium N.V. | Improvements to the bleaching process for chemical pulp and intermediate pulp dispersions |
WO1999046440A1 (en) * | 1998-03-10 | 1999-09-16 | Solvay (Societe Anonyme) | Method for bleaching paper pulp |
WO1999046441A1 (en) * | 1998-03-10 | 1999-09-16 | Solvay (Societe Anonyme) | Method for bleaching and/or delignification of paper pulp |
WO1999054544A1 (en) * | 1998-04-17 | 1999-10-28 | Alberta Research Council Inc. | Method of producing lignocellulosic pulp from non-woody species |
KR100260833B1 (en) * | 1997-12-27 | 2000-07-01 | 차동천 | Method of manufacturing high yield mechanical pulp |
WO2000073576A1 (en) * | 1999-06-01 | 2000-12-07 | Aga Aktiebolag | Bleaching of lignin and process for producing paper |
US6590120B1 (en) | 1998-03-09 | 2003-07-08 | Kemira Chemicals Oy | Methods for the preparation of an N-bis-[2-(1,2-dicarboxy-ethoxy)-ethyl]amine derivative and products of the methods and their uses |
GB2391011A (en) * | 2002-07-19 | 2004-01-28 | Crosmill Ltd | Bleaching cellulose suspensions |
WO2010084351A1 (en) * | 2009-01-26 | 2010-07-29 | Innospec Limited | Chelating agents and methods relating thereto |
WO2011059376A1 (en) * | 2009-11-11 | 2011-05-19 | Metso Paper, Inc. | Method of producing pulp from lignocellulosic material containing silica |
WO2014140852A3 (en) * | 2013-03-14 | 2015-01-08 | Gp Cellulose Gmbh | A method of making highly functional, low viscosity kraft fiber using an acidic bleaching sequence and a fiber made by the process |
WO2014140940A3 (en) * | 2013-03-15 | 2015-01-08 | Gp Cellulose Gmbh | A low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the same |
WO2015138335A1 (en) * | 2014-03-12 | 2015-09-17 | Gp Cellulose Gmbh | A low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the same |
US9511167B2 (en) | 2009-05-28 | 2016-12-06 | Gp Cellulose Gmbh | Modified cellulose from chemical kraft fiber and methods of making and using the same |
US9512237B2 (en) | 2009-05-28 | 2016-12-06 | Gp Cellulose Gmbh | Method for inhibiting the growth of microbes with a modified cellulose fiber |
US9512561B2 (en) | 2009-05-28 | 2016-12-06 | Gp Cellulose Gmbh | Modified cellulose from chemical kraft fiber and methods of making and using the same |
US9512563B2 (en) | 2009-05-28 | 2016-12-06 | Gp Cellulose Gmbh | Surface treated modified cellulose from chemical kraft fiber and methods of making and using same |
US10865519B2 (en) | 2016-11-16 | 2020-12-15 | Gp Cellulose Gmbh | Modified cellulose from chemical fiber and methods of making and using the same |
CZ309643B6 (en) * | 2021-07-21 | 2023-06-07 | Univerzita Pardubice | Magnesium salts of aspartic acid derivatives and their use as hydrogen peroxide stabilizers |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2288752B1 (en) | 2008-06-20 | 2014-03-12 | International Paper Company | Composition and recording sheet with improved optical properties |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
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EP0509382A2 (en) * | 1991-04-17 | 1992-10-21 | Hampshire Chemical Corporation | Biodegradable bleach stabilizers for detergents |
WO1994003553A1 (en) * | 1992-08-01 | 1994-02-17 | The Procter & Gamble Company | Peroxy bleaching composition stabilized with ethylenediamine-n,n'-disuccinic acid |
WO1995014808A1 (en) * | 1993-11-24 | 1995-06-01 | Henkel Kommanditgesellschaft Auf Aktien | Use of nitrogen-containing complexing agents in the bleaching of wood pulp |
WO1996019557A2 (en) * | 1994-12-22 | 1996-06-27 | Basf Aktiengesellschaft | Use of hydroxyalkylaminocarboxylic acids as complexing agents |
-
1996
- 1996-02-19 FI FI960756A patent/FI115469B/en not_active IP Right Cessation
-
1997
- 1997-02-19 EP EP97903408A patent/EP0882151B1/en not_active Expired - Lifetime
- 1997-02-19 AT AT97903408T patent/ATE252176T1/en not_active IP Right Cessation
- 1997-02-19 WO PCT/FI1997/000106 patent/WO1997030208A1/en active IP Right Grant
- 1997-02-19 DE DE69725558T patent/DE69725558T2/en not_active Expired - Lifetime
- 1997-02-19 AU AU17973/97A patent/AU1797397A/en not_active Abandoned
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0509382A2 (en) * | 1991-04-17 | 1992-10-21 | Hampshire Chemical Corporation | Biodegradable bleach stabilizers for detergents |
WO1994003553A1 (en) * | 1992-08-01 | 1994-02-17 | The Procter & Gamble Company | Peroxy bleaching composition stabilized with ethylenediamine-n,n'-disuccinic acid |
WO1995014808A1 (en) * | 1993-11-24 | 1995-06-01 | Henkel Kommanditgesellschaft Auf Aktien | Use of nitrogen-containing complexing agents in the bleaching of wood pulp |
WO1996019557A2 (en) * | 1994-12-22 | 1996-06-27 | Basf Aktiengesellschaft | Use of hydroxyalkylaminocarboxylic acids as complexing agents |
Cited By (45)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1998004775A1 (en) * | 1996-07-26 | 1998-02-05 | Basf Aktiengesellschaft | Use of complexing agents for cellulose and wood bleaching, paper production and used paper deinking |
WO1999027178A1 (en) * | 1997-11-25 | 1999-06-03 | Amylum Belgium N.V. | Improvements to the bleaching process for chemical pulp and intermediate pulp dispersions |
KR100260833B1 (en) * | 1997-12-27 | 2000-07-01 | 차동천 | Method of manufacturing high yield mechanical pulp |
US6590120B1 (en) | 1998-03-09 | 2003-07-08 | Kemira Chemicals Oy | Methods for the preparation of an N-bis-[2-(1,2-dicarboxy-ethoxy)-ethyl]amine derivative and products of the methods and their uses |
BE1011784A3 (en) * | 1998-03-10 | 2000-01-11 | Solvay | Bleaching pulp process. |
BE1011785A3 (en) * | 1998-03-10 | 2000-01-11 | Solvay | Process for laundering and / or pasta delignification paper chemicals. |
WO1999046441A1 (en) * | 1998-03-10 | 1999-09-16 | Solvay (Societe Anonyme) | Method for bleaching and/or delignification of paper pulp |
WO1999046440A1 (en) * | 1998-03-10 | 1999-09-16 | Solvay (Societe Anonyme) | Method for bleaching paper pulp |
WO1999054544A1 (en) * | 1998-04-17 | 1999-10-28 | Alberta Research Council Inc. | Method of producing lignocellulosic pulp from non-woody species |
US6258207B1 (en) | 1998-04-17 | 2001-07-10 | Alberta Research Council Inc. | Alkaline peroxide mechanical pulping of non-woody species |
WO2000073576A1 (en) * | 1999-06-01 | 2000-12-07 | Aga Aktiebolag | Bleaching of lignin and process for producing paper |
US6679972B1 (en) | 1999-06-01 | 2004-01-20 | Aga Aktiebolag | Process for the bleaching of a pulp suspension by separating calcium from lignin |
GB2391011A (en) * | 2002-07-19 | 2004-01-28 | Crosmill Ltd | Bleaching cellulose suspensions |
US8801962B2 (en) | 2009-01-26 | 2014-08-12 | Innospec Limited | Chelating agents and methods relating thereto |
WO2010084351A1 (en) * | 2009-01-26 | 2010-07-29 | Innospec Limited | Chelating agents and methods relating thereto |
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CZ309643B6 (en) * | 2021-07-21 | 2023-06-07 | Univerzita Pardubice | Magnesium salts of aspartic acid derivatives and their use as hydrogen peroxide stabilizers |
Also Published As
Publication number | Publication date |
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DE69725558T2 (en) | 2004-08-05 |
EP0882151B1 (en) | 2003-10-15 |
FI115469B (en) | 2005-05-13 |
ATE252176T1 (en) | 2003-11-15 |
FI960756A0 (en) | 1996-02-19 |
FI960756A (en) | 1997-08-20 |
EP0882151A1 (en) | 1998-12-09 |
AU1797397A (en) | 1997-09-02 |
DE69725558D1 (en) | 2003-11-20 |
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