EP2567024A1

EP2567024A1 - Fibrous composition for paper and card production

Info

Publication number: EP2567024A1
Application number: EP11716963A
Authority: EP
Inventors: Christian Jehn-Rendu; Hans-Georg Lemaire; Oliver Koch; Tilo Habicher; Sylke Haremza; Markus Hoffmann
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2010-05-05
Filing date: 2011-05-04
Publication date: 2013-03-13
Also published as: WO2011138366A1; CN102869830A; CA2795834A1; BR112012027210A2

Abstract

The present invention relates to a novel fibrous composition for paper or card production, which contains an oxidized wastepaper stuff and/or an oxidized mechanical stuff into which 1 to 500 mmol of carboxyl groups per kg and 1 to 200 mmol of aldehyde groups per kg were introduced by oxidation. The invention also relates to paper and card based on such a fibrous composition and also to a process for producing such a paper or card. The invention also relates to the use of oxidized wastepaper stuff and/or oxidized mechanical stuff to improve the retention and drainage properties of a stuff suitable for the production of paper or card. The invention further relates to the use of oxidized wastepaper stuff and/or oxidized mechanical stuff to improve, i.e. enhance, the dry strength of paper and card.

Description

Fibrous Composition for Paper and Board Production Description The present invention relates to a novel pulp composition for papermaking or paperboard production which contains an oxidized waste paper pulp and / or an oxidized mechanical pulp. The invention also relates to paper and board based on such a pulp composition and to a method for producing such a paper or board. The invention also relates to the use of oxidized waste paper pulp and / or oxidized mechanical pulp to improve the retention and drainage properties of a pulp suitable for the manufacture of paper or board. The invention further relates to the use of oxidized waste paper pulp and / or oxidized mechanical pulp for improvement, i. H. Increasing the dry strength of paper and cardboard.

Many papers are today produced using waste paper pulp, ie a pulp obtained by recycling waste paper, or using mechanical pulp. Since the cost of waste paper pulp or of mechanical material is substantially lower than for fresh pulp, an increase in the proportion of waste paper pulp or of mechanical pulp in the paper pulp or paper pulp. Paperboard production used a great economic advantage for the paper manufacturer. Frequently, however, the quality of the waste paper pulp leaves much to be desired if the structure of the fibers is damaged in the recycling of paper and cardboard or in the mechanical pulping of wood, which leads to lower strength values in the paper. Therefore, the amount of waste paper pulp or mechanical pulp in the pulp used to make the paper or paperboard is limited. However, an increase in the content of waste paper pulp and / or mechanical pulp is desirable for the reasons mentioned above. It has been reported on various occasions to use a stock for papermaking in which the cellulose fibers have previously been subjected to oxidation.

Thus, WO 99/231 17 describes a process for the oxidation of cellulose fibers in paper stocks, in which a paper pulp with an oxidizing enzyme, for. As a laccase, oxidized in the presence of a mediator. As pulps, mechanical, chemical, chemo-mechanical and recycled substances are proposed. The process allegedly leads to improved flexibility, improved water retention capacity (WRV) and increased strength. EP 1077286 describes the use of an aldehyde-modified cellulose pulp for the production of paper. The aldehyde groups are incorporated into the cellulose pulp by chemical oxidation, e.g. B. with sodium hypochlorite in the presence of a Mediators, introduced. The thus modified cellulose pulp leads in particular to an improved wet tensile strength and to an increase of the ratio of wet to dry tensile strength. A similar situation is known from EP 1 106732, in which case additionally a hydroxyl-containing polymer is used.

WO 00/68500 also describes a process for producing paper having improved wet strength properties using an unbleached or semi-bleached pulp, a semi-pulp or a waste paper pulp which has been treated with a phenol oxidizing enzyme, for example a laccase in the presence of a mediator, e.g. , TEMPO (2,2,6,6-tetramethylpiperidinyloxyl).

WO 01/29309 likewise describes a process for the production of paper in which a pulp is used whose cellulose fibers have been previously treated with an oxidizing agent in the presence of a mediator. Again, the oxidation leads to an improvement in the wet strength properties of the paper.

Although the use of oxidized pulps is described in the prior art referred to herein, such oxidized pulps are not used in the paper industry. One reason for this may possibly be that the cellulose fibers are damaged by the oxidation in their structure, which leads to a deterioration of the dry strength properties of the paper, in particular the continuation / tearing work. The observed improvement in wet tensile strength, however, increases significantly compared to untreated fibers, z. B. up to ten times, compared to untreated fibers to. However, this is not desirable in many cases, as this significantly increases the energy consumption during the reprocessing of the paper.

A further problem in the production of paper or board is the often unsatisfactory retention properties of the pulp compositions used for paper or board production, in particular those pulp compositions with a high content of waste paper and / or mechanical or thermomechanical material, so that larger quantities must be used on retention aids. Often, the drainage properties of the compositions are unsatisfactory.

It is an object of the present invention to provide pulp compositions for papermaking which improve the disadvantages of the prior art. It has surprisingly been found that an oxidized pulp, in the conventional pulp selected by oxidation of at least one conventional pulp selected from waste paper pulp, mechanical pulp and mixtures thereof, has from 1 to 500 mmol of carboxyl groups and 1 to 200 mmol aldehyde groups per kg of conventional pulp, calculated oven-dry, the retention properties of pulp compositions or of aqueous pulp suspension for papermaking improved by, for example, an increase in the total retention FPR and / or an increase in ash retention, as for example by The "Britt Jar Test Method" TAPPI T-261 can be determined. This is especially true for paper and board, which is made of a pulp composition, which in addition to the oxidized pulp as component B and chemical pulp (= pulp) as component A and at least one other, conventional, chemical of the component A and the oxidized pulp B comprises different pulp C, the total amount of oxidized pulp and chemical pulp in the pulp composition being from 30 to 80% by weight of the total pulp in the pulp composition and the ingredients A, B and C at least 70% by weight, especially at least 80% Wt .-% and especially make up at least 90 wt .-% or 100 wt .-% of the total pulp in the pulp composition, wherein the amounts of the components A, B and C are each counted as oven-dry substance. Moreover, the use of such an oxidized pulp B leads to an improvement in the dry strength properties of paper or board, without there being a strong increase in the wet strength properties. In addition, it is found that the use of such oxidized fibers can improve the dewatering properties of the aqueous pulp suspension, ie the dewatering time is shortened in the papermaking, as z. B. according to ISO standard 5267 can be determined. Accordingly, the present invention relates to the use of an oxidized pulp B in which by oxidation of at least one conventional pulp selected from waste paper pulp, mechanical pulp and blends thereof 1 to 500 mmol, especially 5 to 200 mmol, especially 10 to 150 mmol carboxyl groups per kg of conventional pulp and from 1 to 200 mmol, in particular from 2 to 150 mmol and especially from 5 to 100 mmol aldehyde groups per kg of conventional pulp were used to improve the retention properties or to improve the drainage properties of the pulp compositions defined herein and below and / or to improve the dry strength properties, in particular dry tensile strength, tensile strength, tear propagation strength and bursting pressure of paper or board, particularly paper or board, using the fibrous material defined herein and hereinafter fassensetzungen is produced.

Furthermore, the present invention relates to the use of an oxidized fiber B, in which by oxidation of at least one selected from paper pulp, mechanical material and mixtures thereof conventional pulp 1 to

500 mmol, in particular 5 to 200 mmol, especially 10 to 150 mmol of carboxyl groups per kg of conventional pulp and 1 to 200 mmol, in particular 2 to 150 mmol and especially 5 to 100 mmol aldehyde groups per kg of conventional pulp were introduced to improve the retention properties of aqueous pulp suspensions, in particular such pulp suspension, the fiber constituents as the fiber composition here and below contain.

Accordingly, the present invention relates to the use of an oxidized pulp B in which by oxidation of at least one conventional pulp selected from waste paper pulp, mechanical pulp and blends thereof 1 to 500 mmol, especially 5 to 200 mmol, especially 10 to 150 mmol carboxyl groups per kg of conventional pulp and 1 to 200 mmol, in particular 2 to 150 mmol and especially 5 to 100 mmol aldehyde groups per kg of conventional pulp, to improve the dewatering properties of aqueous pulp suspensions, in particular those pulp suspensions containing as fiber constituents the pulp composition shown here and below.

Another object of the invention is a pulp composition for paper or board production, comprising

a) at least one chemical pulp A and

b) at least one oxidized pulp B, in the conventional pulp selected by oxidation of at least one of conventional pulp, mechanical pulp and mixtures thereof 1 to 500 mmol, especially 5 to 200 mmol, especially 10 to 150 mmol carboxyl groups per kg of conventional pulp and 1 to 200 mmol, in particular 2 to 150 mmol and especially 5 to 100 mmol aldehyde groups per kg of conventional pulp were introduced, and c) at least one other, different from A and B, conventional pulp C;

wherein the total amount of the components A and B account for 30 to 80 wt .-% of the total pulp in the pulp composition and the ingredients A, B and C at least 70 wt .-%, in particular at least 80 wt .-% and especially at least 90 wt. % or 100% by weight of the total mass of pulp in the pulp composition, the stated amounts of constituents A, B and C each being calculated as oven-dry pulp.

The present invention furthermore relates to a paper stock which contains, as fiber constituents, a pulp composition as described herein, as well as papers or paperboard based on such a pulp composition. The use of an oxidized pulp B, as described here, allows, with the same dry strength properties, the proportion of waste paper pulp and / or mechanical pulp in the fiber pulp used for paper or board production. Increase composition at the expense of the more expensive chemical. In other words, a paper or board produced using a pulp composition according to the invention has, for the same proportion of chemical substance and the same proportion of waste paper and / or mechanical material (oxidized pulp B plus any conventional waste paper pulp present and / or or mechanical fabric) has better dry strength properties than a paper or paperboard made using a pulp composition containing only conventional waste paper pulp or mechanical pulp besides chemical pulp. In this way, it is possible to increase the total amount of waste paper and / or mechanical material (oxidized pulp B plus any existing conventional waste paper pulp and / or mechanical pulp) by at least 50%, in particular at least 90%, in the pulp composition without any loss have to accept in the dry strength properties. In addition, it is found that the wet strength properties are not or only slightly increased, that is, in an insignificant for a later retrieval height, which is advantageous in terms of any recycling of a paper or cardboard made from this pulp composition. Due to the better retention properties, it is also possible to increase the proportion of filler in the pulp suspension, based on the total amount of substance.

According to the invention, the pulp composition contains as ingredient A a chemical pulp, d. H. Pulp obtained by chemical pulping of a lignocellulosic material such as wood. These include, for example, sulfate pulp, sulfite pulp and / or soda pulps, wherein the pulp may be unbleached or bleached. Among the bleached pulps, chlorine-bleached or, in particular, low-chlorine or chlorine-free pulps, such as ECF pulp and TCF pulp, are used. Preference is given to unbleached pulp. Also suitable is pulp from annual crops, such as pulp based on rice, wheat, sugar cane (bark), bamboo or kenaf.

The chemical pulp is usually used only in small quantities. Already a few wt .-% of the component A, based on the total mass of material in the pulp composition, are usually sufficient to achieve the desired strengths. Typically, the level of chemical pulp in the fiber composition is in the range of 1 to 50 weight percent, often in the range of 2 to 30 weight percent, and more preferably in the range of 5 to 20 weight percent, based on total fabric weight in the pulp composition.

The amount of oxidized fibers B, namely oxidized waste paper pulp and / or oxidized mechanical pulp, is typically 10 to 79 wt .-%, often 20 to 68 wt .-% and in particular 30 to 55 wt .-%, based on total mass in the pulp composition. The amount of chemical pulp A and oxidized pulp B is according to the invention 20 to 80 wt .-%, often 30 to 70 wt .-% and in particular 40 to 60 wt .-%, based on the total mass of matter in the pulp composition.

In addition to the aforementioned fibers of components A and B, the pulp composition contains as constituent C according to the invention at least one further conventional pulp, which is different from the pulps A and B. These fibers include in particular conventional waste paper and conventional wood pulp, such as wood pulp (= mechanical pulp), z. B. white ground or brown ground, thermomechanical pulp (thermomechanical pulp TMP), chemo-thermomechanical pulp (CTMP), semi-pulp, high yield pulp and refiner mechanical pulp (RMP). As component C, in addition to waste paper and mechanical material, d. H. Wood pulp, thermomechanical pulp (TMP) and refiner mechanical pulp (RMP) are preferred. Particularly preferred are waste paper pulp and mechanical pulp and mixtures thereof. Very particularly preferred component C is used paper pulp (recycled fibers) and fiber blends which consist of at least 30% by weight, in particular at least 50% by weight, based on the total mass of the constituents C, of recovered paper stock, preferably mixed with mechanical pulp ,

As a conventional waste paper material here is any paper into consideration, which was obtained from any type of used, printed or unprinted paper, in particular waste paper according to the list of varieties EN 643, the waste paper of the same or different quality may be such. B. Deinkingware DIP (1 .1 1), old newsprint (ONP), non-presorted office waste (MOW), pre-sorted office waste (SOW), (old) magazines / magazines (HOMP), colorful files (2.06 according to EN 643), used (paper) packaging (OCC) and / or mixed waste paper, including B. mixed bales (1 .02), Kaufhausaltpapier (1 .04), corrugated board Il (4.03), multi-pressure (3.10), white rotary waste (3.14 / 3.15) and white envelope chips (3.18.01) may include. The numbers in parentheses indicate the number assigned to EN 643, respectively. It may also be appropriate waste or packaging made of cardboard or paperboard, including composites of paper, cardboard or cardboard with other materials, such as plastic coatings or linings act. The essential aspect of the waste paper pulp used in accordance with the invention is that, in contrast to fresh fiber material which has hitherto not undergone any disruption or which has not yet been processed into paper or paperboard products, it is recycled waste paper material. One speaks here also of secondary fibers. Coated paper also includes coated broke, which in addition to fiber components also contains binders from the coating color. In the fiber compositions according to the invention, constituents B and C generally make up 50 to 99% by weight, frequently 60 to 98% by weight, in particular 70 to 98% by weight, in particular 70 to 95% by weight and especially 80% to 95 wt .-%, based on total mass in the pulp composition.

In the fibrous compositions of the invention, the total amount of components A, B and C is at least 70% by weight, often at least 80% by weight, especially at least 90% by weight, and especially at least 99 or 100% by weight, based on Total mass of material in the pulp composition. In addition, the pulp composition may contain up to 30% by weight, but often not more than 20 or 10% by weight or essentially no (<1% by weight) of other fiber constituents.

Here and below, the term total mass of matter means the dry mass of the fiber components (oven-dry, water content <1%) in the pulp composition.

As constituent B, the pulp composition contains at least one oxidized pulp selected from oxidized waste paper pulp, oxidized mechanical pulp and mixtures thereof. A mechanical material is understood to mean groundwood such as white or brown ground. This is a fiber mass based on the aforementioned substances, in which by an oxidation process 1 to 500 mmol, in particular 5 to 200 mmol, especially 10 to 150 mmol carboxyl groups per kg of conventional pulp and 0 to 200 mmol, in particular 2 to 150 mmol and especially 5 to 100 mmol aldehyde groups per kg of conventional pulp were introduced. These quantities relate to the amount of carboxyl groups or aldehyde groups introduced by the oxidation process and not to the total amount of carboxyl and aldehyde groups present in the waste paper pulp or in the mechanical pulp, which is generally higher, since conventional waste paper or paper pulp is also used a mechanical substance usually already contains aldehyde and / or carboxyl groups.

Preference is given to oxidized waste paper pulp and mixtures of oxidized waste paper pulp with oxidized mechanical pulp, in which the proportion of oxidised waste paper pulp is at least 30% by weight, in particular at least 50% by weight, based on the total mass of constituents B.

The amount of aldehyde and carboxyl groups introduced into the substance by oxidation can be determined by the expert in a manner known per se by determining the absolute content of aldehyde or carboxyl groups before and after oxidation. The absolute determination of the aldehyde and carboxyl groups is achieved by customary titration methods, as used in the prior art, for. In EP 1077286 or EP 1 106732, be written. The determination of the aldehyde groups is typically carried out by derivatization of the aldehyde with hydroxylammonium chloride and titration of the liberated hydrogen chloride with sodium hydroxide solution. The content of carboxyl groups is typically determined by titration with sodium hydroxide solution.

Oxidation of the conventional material is believed to produce additional aldehyde and carboxyl groups on the surfaces of the cellulose fibers contained in the waste paper pulp, i. H. in the cellulose and hemicellulose constituents of these fibers, are generated, e.g. By oxidation of the C6-OH group in the glucose units of the cellulosic and hemicellulose components of the cellulosic fibers. Furthermore, it is believed that the laccase preferred for the oxidation of the pulps leads to changes in the lignin content of the pulps. It is believed that these modifications of the pulp constituents in the waste paper pulp or mechanical or thermomechanical pulp, in combination with the virgin pulp contained in the pulp composition, improve the retention and drainage properties of the pulp composition and improve the dry strength properties of the pulp Pulp composition produced paper or cardboard lead. Furthermore, it has proved to be advantageous if the molar ratio of the carboxyl groups introduced by oxidation to the aldehyde groups introduced by oxidation is not below 0.8: 1, preferably not below 1: 1 and in particular not below 1.2: 1. This molar ratio is preferably in the range from 0.8: 1 to 10: 1, in particular in the range from 1: 1 to 8: 1 and especially in the range from 1, 2: 1 to 5: 1.

The oxidation of the conventional pulp can be carried out in a conventional manner. The amount of aldehyde groups and carboxyl groups introduced by oxidation can be controlled by those skilled in the art by choosing appropriate reaction conditions, reagent amounts, and by determining the necessary reaction conditions and reagent levels by routine experimentation.

As a conventional mechanical material, wood pulp such as white or brown sanding can be considered, which can be bleached or unbleached.

As a conventional waste paper material for the oxidation of any paper pulp, which was obtained from any type of used, printed or unprinted paper, in particular waste paper according to the list of varieties EN 643, wherein the waste paper of the same or different quality may be such. B. Deinkingware (DIP) (1 .1 1), Old Newsprint (ONP), Non-Presorted Office Waste (MOW), Presorted Office Waste (SOW), (Old) Magazines / Magazines (HOMP), colorful files (2.06 according to EN 643), used (paper) packaging (OCC) and / or mixed waste paper, including z. B. mixed bales (1.02), Kaufhausaltpapier (1.04), corrugated board Il (4.03), multi-pressure (3.10), white rotary waste (3.14 / 3.15) and white envelope chips (3.18.01) may include. The numbers in parentheses indicate the number assigned to EN 643, respectively. It may also be equivalent waste or packaging of cardboard or paperboard, including paper, cardboard or paperboard composites with other materials, such as plastic coatings or liners. The essential aspect of the waste paper pulp used in accordance with the invention is that, in contrast to fresh fiber material which has hitherto not undergone any disruption or which has not yet been processed into paper or paperboard products, it is recycled waste paper material. One speaks here also of secondary fibers. The waste paper to be considered for oxidation also includes coated broke, which in addition to fiber components also contains binders from the coating color. For oxidation, both conventional chemical methods and enzymatic oxidation methods can be used. For the quality of the oxidized substance, it has proved to be advantageous if the oxidation is carried out enzymatically. This is presumably due to the fact that damage to the cellulose fibers by oxidative cleavage is minimized in this way.

For enzymatic oxidation, the conventional waste paper pulp is treated with atmospheric oxygen in the presence of an oxidase or with hydrogen peroxide in the presence of a suitable peroxidase. Oxidases such as catechol oxidase (EC 1 .10.3.1), laccases (EC 1 .10.3.2), bilirubin oxidases (EC 1.3.3.5) are preferred. Preferably, the oxidation-mediating enzyme is a laccase. Basically, all laccases are suitable. For example, the laccases may be of the strains Polyporus sp., In particular Polyporus pinsitus (also called Trametes villosa), Polyporus versicolor (= Trametes versicolor), Myceliophthora sp., For example M. thermophila, Rhizoctonia sp., In particular Rhizoctonia praticola or Rhizoctonia solani , from Scytotidium sp., in particular S. thermophilium, from Pyricularia sp., in particular Pyricularia oryzae or Coprinus sp. be derived as C. cinereus. The laccases may also be derived from fungi such as Collybia, Fomes, Lentinus, Pleurotus, Aspergillus, Neurospora, Podospora, Phlebia, for example P. radiata (see WO 92/01046), Coriolus sp., E.g. C. hirsitus (JP 2-238885), or Botrytis. Suitable laccases are known to the person skilled in the art and otherwise commercially available.

The amount of laccase is usually chosen so that its activity in the range of 0.1 to 14 000 U, in particular in the range of 0.5 to 1 000 U, and more preferably in the range of 1 to 400 U, each based on 1 g of oven-dried conventional substance. The enzyme activity can be determined in the usual way with the aid of the substrate syringaldazine (4,4 '- (azinobis (methanylyliden)) bis (2,6-dimethoxyphenol)). The rate of oxidation of syringaldazine to the corresponding quinone (4,4'-azobis (methanylylidene)) bis (2,6-dimethoxycyclohexa-2,5-diene-1-one) is determined by measuring the absorbance at 530 nm , 1 unit (U) corresponds to the turnover of 1 μΜοΙ syringaldazine per minute.

For oxidation, the paper pulp or the mechanical material is usually transferred into an aqueous suspension and mixed with the enzyme. By moving the suspension or by introducing oxygen, the amount of oxygen required for the oxidation is introduced. When using peroxidases for the oxidation of hydrogen peroxide is of course also added as an oxidizing agent.

Fresh water, but also process water, can be used as water for the preparation of the aqueous suspension of the waste paper pulp or mechanical pulp. The consistency in the aqueous suspension is typically in the range from 1 to 100 g / l, in particular in the range from 5 to 80 g / l and especially in the range from 10 to 50 g / l (in each case based on oven-dry paper stock or mechanical material) , The pH of the aqueous suspension depends in a manner known per se on the optimum pH for the particular enzyme and can be adjusted by adding acids or bases or buffers, in particular by adding sodium hydroxide solution, potassium hydroxide solution or a buffer such as potassium dihydrogen phosphate buffer and optionally controlled in the course of the oxidation by the addition of base. Typically, the pH of the aqueous recovered pulp suspension is in the range of 3 to 10, and more preferably in the range of 4 to 9.

The temperature at which the oxidation is carried out, of course, depends on the oxidant used. In the case of an enzymatic oxidation, the temperature preferably depends on the optimum temperature for the activity of the particular enzyme chosen. Typically, the temperature is in the range of 20 to 40 ^° C.

The oxidation time depends in a conventional manner on the type and amount of each selected oxidant and the other reaction conditions such as temperature and pH, in the case of enzymatic oxidation of activity and

Amount of enzyme used under the respective reaction conditions, from. The optimum reaction conditions for the oxidation can be determined by the person skilled in the art in the context of routine experiments. Typically, the oxidation time is in the range of 5 minutes to 24 hours, more preferably in the range of 10 minutes to 18 hours and more preferably in the range of 20 minutes to 12 hours. In a preferred embodiment of the invention, the oxidation of the conventional pulp takes place in the presence of at least one mediator compound, hereinafter also referred to as redox mediator. The function of the redox mediator is that the oxidizing agent does not react directly with the OH groups in the glucose units of the cellulose and hemicellulose components or with the lignin constituents, but first oxidizes the mediator, which in turn oxidizes the material contained in the conventional pulp (Hemi ) Cellulose fibers or lignin causes. The use of a mediator is particularly advantageous in the case of enzymatic oxidation.

Examples of suitable mediator compounds are in principle all compounds described in the prior art for this purpose, for example those described in US Pat

WO 00/68500, pages 8 and 9 described compounds, for example

Benzothiazoline compounds such as 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonate) (ABTS), 2- (p-aminophenyl) -6-methylbenzothiazole-7-sulfonic acid and 3-methyl-2-benzothiazolinone;

Naphthalene compounds, such as. 6-hydroxy-2-naphthalenecarboxylic acid, 7-methoxy-2-naphthol, 7-amino-2-naphthalenesulfonic acid, 5-amino-2-naphthalenesulfonic acid, 1, 5-diaminonaphthalene and 7-hydroxy-1,2-naphthimidazole;

Phenothiazine compounds such as 10-methylphenothiazine, 10-phenothiazinepropionic acid (PPT), N-hydroxysuccinimide-10-phenothiazine propionate, 10-ethyl-4-phenothiazinecarboxylic acid, 10-ethylphenothiazine, 10-propylphenothiazine, 10-isopropylphenothiazine, Methyl phenothiazine-1-ylpropionate, 10-phenylphenothiazine, 10-allyl-phenothiazine, 10- (3- (4-methyl-1-piperazinyl) -propyl) -phenothiazine, 10- (2-pyrrolidinomethyl) -phenothiazine, 10- (2 -Hydroxyethyl) phenothiazine, 2-acetyl-10-methylphenothiazine or 10- (3-hydroxypropyl) phenothiazine;

Benzidine compounds, such as. Benzidine or 3,3'-dimethoxybenzidine;

Stilbene compounds such as 4-amino-4'-methoxystilbene, 4,4'-diaminostilbene-2,2'-disulfonic acid or iminostilbene;

Phenoxazine compounds such as 10-phenoxazine-propionic acid (POP), 10-methylphenoxazine, or 10- (2-hydroxyethyl) phenoxazine;

N- (4 (dimethylamino) benzylidene) -p-anisidine;

triphenylamine;

Biphenylamines such as N-benzylidene-4-biphenylamine or 4,4'-dimethoxy-N-methyldiphenylamine;

the phenol compounds described in WO 96/10079, such as acetosyringone, syringaldehyde, methylsyringate, syringic acid, ethylsyringate, propylsyringate, butylsyringate, hexylsyringate, octylsyringate, vanillic acid, NAH, HOBT, PPO and violoric acid;

furthermore the compounds described in WO 95/01426, pages 9 to 11 and in particular sterically hindered nitroxyl compounds or nitroxyl radicals, such as TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxy), and derivatives of TEMPO , such as acetamido-TEMPO, BI-TEMPO, 4-hydroxy-TEMPO, 4-methoxy-TEMPO, 4-benzyloxy- TEMPO, 4-amino-TEMPO, 4-acetylamino-TEMPO, 4-ethylcarbonylamino-TEMPO, 4-propylcarbonylamino-TEMPO, 4-isopropylcarbonylamino-TEMPO,

4-1-methylethylcarbonylamino-TEMPO, 2,2,6,6-tetramethyl-piperidine-1-oxy-4-y-oxalic acid methyl ester, 2,2-dimethyl-4-oxa-1 -aza-1-oxy-spiro [ 5.5] undecane, 4-acetoxy-TEMPO, 7,7-dimethyl-9-oxa-6-aza-6-oxy-spiro [4.5] decane, 7,7,9,9-tetramethyl-1, 4-dioxa- 8-aza-8-oxy-spiro [4.5] decane, 1-ethyl-3- (2,2,6,6-tetramethyl-piperidin-1-oxy-4-yl) urea, 1-isopropyl-3 ( 2,2,6,6-tetramethyl-piperidin-1 -oxy-4-yl) urea, 1-propyl-3- (2,2,6,6-tetramethyl-piperidin-1-oxy-4-yl) -urea , 1-Butyl-3- (2,2,6,6-tetramethylpiperidine-1-oxy-4-yl) urea, 1-iso-Butyl-3- (2,2,6,6-tetramethylpiperidine-1 -oxy-4-yl) urea, 1-phenyl-3- (2,2,6,6-tetramethyl-piperidin-1-oxy-4-yl) -urea, 1,1-diethyl-3- (2,2 , 6,6-tetramethylpiperidin-1 -oxy-4-yl) urea, 1-ethyl-3- (2,2,6,6-tetramethylpiperidine-1-oxy-4-yl) thiourea, 1, 1-Diisopropyl-3- (2,2,6,6-tetramethyl-piperidin-1-oxy-4-yl) -urea, (2,2,6,6-tetramethyl-piperidin-4-yl-4-oxy- ) carbamic acid ethyl ester, (2,2,6,6-tetramethyl-piperidin-4-y propyl 1- (4-oxy) -carbamate, isopropyl (2,2,6,6-tetramethylpiperidin-4-yl-4-oxy) carbamate, (2,2,6,6-tetramethylpiperidin-4-yl) 4-oxy) -carbamic acid butyl ester, (2,2,6,6-tetramethyl-piperidin-4-yl-4-oxy) -carbamic acid isobutyl ester, 7,7,9,9-tetramethyl-2-propyl-1, 3.8 -triaza-1-oxy-spiro [4.5.] decan-4-one, 7,7,9,9-tetramethyl-2-isopropyl-1,3,8-triaza-1-oxyspiro [4.5.] decane 4-one, 7,7,9,9-tetramethyl-2-ethyl-1,3,8-triaza-1-oxyspiro [4.5.] Decan-4-one, 7,7,9,9-tetramethyl-2 -butyl-1,3,8-triaza-1-oxyspiro [4.5.] decan-4-one, 4-acetylamino-2,2,6,6-tetramethyl-piperidine-1 -oxy-4-carboxylic acid, 4- Methyl acetylamino-2,2,6,6-tetramethylpiperidine-1-oxy-4-carboxylate, 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxy-4-carboxylate, 4-acetylamino 2,2,6,6-tetramethylpiperidine-1 -oxy-4-carboxylic acid isopropyl ester, propyl 4-acetylamino-2,2,6,6-tetramethyl-piperidine-1 -oxy-4-carboxylate, further 3,3,5 , 5-tetramethylmorpholine-1 -oxy (TEMMO), 3,4-dehydro-2 , 2,6,6-tetramethylpiperidinyl-1 -oxy, cyclic acetals of 2,2,6,6-tetramethyl-4-piperidone-1 -oxy, 2,2,5,5-tetramethylpyrolidinyl-1 -oxy and similar structures ,

Such sterically hindered nitroxyl compounds are preferred according to the invention.

If a mediator is used, the amount of mediator is generally 1 mg to 100 g, preferably 10 mg to 50 g and in particular 100 mg to 10 g, each based on 1 kg of oven-dry pulp. Preferably, the oxidation is carried out using a laccase as described above in combination with a sterically hindered nitroxyl compound.

In another embodiment, the oxidation occurs in the absence of a mediator compound.

For enzymatic oxidation using atmospheric oxygen, it is usually necessary to atmospheric oxygen in the aqueous suspension of the fibrous material to be oxidized contribute. This is usually achieved by moving the suspension, for example by stirring in suitable vessels, preferably vessels, which are provided with internals to improve the mixing. Optionally, it is also possible to inject atmospheric oxygen into the reaction mixture.

The oxidized pulp B obtainable in this way can be used for the production of a pulp composition according to the invention.

In addition to the abovementioned components A, B and C, the pulp composition may contain up to 10% by weight of further fiber constituents, based on the total fiber mass in the composition, eg. B. Returned Coated Committee.

To prepare the pulp composition, the oxidized pulp B is mixed with chemical pulp A and optionally further, conventional pulp e.

In this case, the procedure is usually such that the aqueous suspension of the oxidized pulp B, as obtained after oxidation, with the pulp component A, preferably also in the form of an aqueous suspension, and optionally conventional pulp C, preferably also in Form of an aqueous suspension, mixed. Of course, it is also possible to suspend dry chemical pulp A and dry pulp C in an aqueous suspension of the oxidized pulp B. It is also possible to recover the oxidized pulp B in dry form and then to suspend it together with chemical pulp A and further pulp C in water and to process the resulting suspension further. Preferably, however, the oxidized pulp B will not be converted to a dry form, but will be mixed directly with the other constituents of the pulp composition in the form of the aqueous suspension obtained during the oxidation.

The present invention further relates to a process for producing a paper or cardboard comprising the following steps:

i) producing an aqueous pulp suspension containing as fiber constituents:

a) at least one chemical pulp A and

b) at least one oxidized pulp B as described herein, and c) at least one other conventional pulp C other than A and B as described herein;

comprising suspending the pulps in water and optionally adding conventional additives and fillers, and ii) dewatering the pulp suspension in a paper machine to form paper or cardboard,

the relative amount of fibers being such that the total amount of ingredients A and B is from 30 to 80% by weight of the total pulp in the pulp suspension and the total amount of ingredients A, B and C is at least 70% by weight. % of the total pulp in the pulp composition, each calculated as oven-dry substance. The relative amounts of the constituents A, B and C in the aqueous pulp suspension correspond to the relative amounts given for the pulp composition and are in particular in the ranges specified there as being preferred.

The provision of the oxidized pulp is carried out in the manner described above. In step i) of the process, an aqueous pulp suspension is then prepared, which contains the oxidized pulp, chemical pulp A and conventional pulp C, in particular the pulp specified as being preferred, in the amounts specified for the pulp composition. To this aqueous suspension then conventional additives and fillers, if required for the paper quality, given. Examples of customary additives are the additives customary in paper production for improving or modifying the paper properties, such as fillers, sizing agents, wet and dry strength agents, antiblocking agents, flame retardants, antistatic agents, water repellents, dyes and optical brighteners, and process chemicals, such as retention, flocculation and dehydrating agents, fixatives, slimicides, wetting agents, defoamers, biocides and the like.

Examples of conventional wet strength agents are the polyamides commonly used for this purpose, epichlorohydrin resins, melamine-formaldehyde resins and cationic glyoxylated polyacrylamides.

Examples of conventional dry strength agents are: native starches, starch derivatives, dextranes, cationized starch, cationic glyoxylated polyacrylamides, polyvinylamines, cationic, anionic or amphoteric polyacrylamides and mixtures thereof with inorganic dry strength agents.

Examples of sizing agents (mass and surface sizing agents) are resin glues, casein and comparable proteins, starch, polymer dispersions, reactive sizing agents, in particular alkyldiketenes and alkylsuccinic anhydrides. In addition, it is also possible to add to the aqueous pulp suspension customary fillers, insofar as these are not already introduced by the waste paper pulp. Examples of suitable fillers are, in particular, calcium carbonate, such as chalk, kaolin, titanium dioxide, gypsum, precipitated calcium carbonate, talc, silicates.

Examples of typical retention aids are aluminum sulfate and polyaluminum chlorite. Microparticle systems of high molecular weight polyacrylamides and bentonite or colloidal silica can also be used as retention aids. As retention agents it is also possible to use combinations of microparticle systems of high molecular weight polyacrylamides and bentonite or colloidal silica with an anionic organic polymer, in particular anionic, optionally crosslinked polyacrylamides. As retention agents based on microparticle systems of this type, it is known, for example, from EP 462365, WO 02/33171, WO 01/34908 or WO 01/34910. As a retention agent it is also possible to use partially hydrolyzed homopolymers of N-vinylformamide and partially hydrolyzed copolymers of N-vinylformamide with diallyldimethylammonium chloride, N, N-dimethylaminoethylacrylamide,

Use Ν, Ν-dimethylaminopropylacrylamide. Further retention aids are microparticle systems of high-molecular-weight polyvinylamines and anionic, cationic or amphoteric, crosslinked polyacrylamides, as are known, for example, from US 2003/0192664 A1. Examples of customary flocculants and dehydrating agents are polyethyleneimines, polyamines having molar masses of more than 50,000, polyamidoamines, which may optionally be prepared by grafting with ethyleneimine and subsequent crosslinking with z. B. Polyethylenglykol- dichlorohydrin ethers or are crosslinked with epichlorohydrin, polyether amines, polyvinyl imidazoles, polyvinyl imidazolines, polyvinyl tetrahydropyridines, Polydialkylaminoalkylvinyl-, Polydialkylaminoalkyl (meth) acrylates in protonated or quaternized form, polydiallyldialkylammonium halides, in particular polydiallyldiamethylammonium.

Examples of conventional fixing agents are: aluminum sulfate, polyaluminum chlorites, as well as the customary for this purpose cationic polymers, eg. Cationic polyacrylamides, polyethylenimines, polyvinylamines, polyimidazolines, polyimidazoles, polyamines, di-cyandiamide resins, poly-DADMAC, Mannich products and Hofmann products.

The type and amount of the process chemicals and the fillers depends in a manner known per se on the requirements of the paper machine and the desired paper type.

Subsequently, the pulp suspension is dewatered in a paper machine to form paper or cardboard. If appropriate, it is possible to dilute with water (so-called thin material) before introducing the pulp suspension. The addition of the process chemicals can be done both before dilution and after dilution. Subsequently, the pulp, which optionally also contains fillers, dewatered in the usual manner to form a sheet. The dewatering is typically carried out in a paper machine in which the usual paper forming steps are carried out, ie sheet forming in the wire section, compaction to remove the bulk of water in the press section, drying in the dryer section, calendering and calendering possibly supercalendering. Optionally, the dryer section may also comprise a size press in which the paper is treated with a low viscosity size liquor for surface hardening. Optionally, the paper machine may also comprise a coating unit in which the paper is coated with a coating color. An overview of the common processes for papermaking can be found in Roempp, Lexikon Chemie, 10th Edition, Thieme Verlag Stuttgart, 1998, pp. 31, 10 to 31, 15 and in Ulman's Encyclopedia of Industrial Chemistry, 5th Edition on CD-ROM (R. -PAT, Paper and Pulp, Wiley-VCH 1997).

The pulp composition according to the invention and the papermaking process according to the invention are suitable for the production of basically all types of paper which typically contain waste paper constituents, in particular

Writing papers, ie filled and fully sized papers with smoothed surfaces, typically having a basis weight in the range of 30 to 80 g / m ² and a filler content in the range of 5 to 30% by weight and whose surfaces are usually painted and containing a proportion of waste paper fibers (total amount of oxidized and unoxidized waste paper fibers) in the range of 10 to 99 wt .-%, based on the total amount of fiber constituents;

Print papers, ie papers which are uncoated or coated and suitable for printing, which typically have a basis weight in the range from 40 to 150 g / m ² and have a filler content of up to 20% by weight, can typically contain a proportion of recovered paper in the paper Range of 10 to 99 wt .-% (total amount of oxidized and unoxidized recycled paper fibers, based on the total amount of fibers); Newsprint papers, which typically have a basis weight in the range of 38 to 50 g / m ² and have a filler content in the range of up to 18% by weight, can typically have a recovered paper content in the range of 10 to 99% by weight. % (Total amount of oxidized and unoxidized recycled paper fibers, based on total fiber content);

Packaging papers, which typically have a basis weight in the range of 70 to 250 g / m ² and may have a filler content of up to 15 wt .-% which typically have a waste paper content in the range of 10 to 99 wt .-% (total amount of oxidized and unoxidized waste paper fibers, based on the total amount of fiber); Cardboard or solid board, which typically has a basis weight in the range from 250 to 1000 g / m ² and can have a filler content of up to 15% by weight, which typically has a waste paper content in the range from 10 to 99% by weight ( Total amount of oxidized and unoxidized recycled paper fibers, based on the total amount of fibers);

The following examples serve to illustrate the invention and are not intended to be limiting.

I. Feedstocks

1.1 Sample material: fiber materials

Waste paper made by Hoya (a mixture of used paper grades 1 .02 / 1 .04 / 4.01) and Sappemeer (fibers from paper grades 0012 to 0015) was used. I.2 Chemicals: TEMPO

TEMPO solid (CAS number: 2564-83-2, catalog number A12733) was obtained as free radical having a purity of 98% from Alfa Aesar GmbH, Karlsruhe, Germany. I.3 enzymes

The laccases used for the oxidation are given in Table 1, indicating the source of supply together with their respective activities.

Table 1 :

The activity of the laccases was determined in the manner described above by oxidation of the substrate syringaldazine to the corresponding quinone. II. Oxidation of waste paper pulp

The whipping took place in a pulper from Escher & Wyss. The capacity of the device is a maximum of 15 liters. Alternatively, Voith pulpers can be used.

In the pulper 500 g waste paper pulp and 12.5 liters of water are added to prepare a 4% suspension and pitched for 15 minutes. The recovered paper pulp suspension thus obtained was subjected to oxidation in a 15 liter bucket which may have baffles. The following components were placed in the bucket:

5.4 liters of the pitched waste paper pulp (216 g pulp dry weight), 0.6 liter of 1 M potassium dihydrogen phosphate buffer, pH 6, the desired amount of T. versicolor laccase and TEMPO. Leave the respective approach overnight, d. H. 14 to 16 h, at room temperature. The amounts of laccase and TEMPO and the reaction time can be varied to set certain oxidation levels or specific CHO to COOH ratios. Experiments 1 and 2 were carried out in 15 L buckets without baffles. The results of the oxidation are shown in Table 2.

Table 2

The data for COOH and CHO in Table 2 refer to the additionally produced by the oxidation CHO and COOH groups. III. Production of test sheets

The production of the test sheets was carried out with a Rapid Kothen leaf former. The following tests were carried out: dry tearing length, wet tearing length, further / tearing work (DIN 531 15) and water retention capacity (WRV) SCAN-C 62:00. The results are shown in Table 3. Table 3

Ref .: Reference value, Ox: oxidized sample, Rel .: relative to background, V: Comparative Example. Tables 2 and 3 show by way of example the results obtained with Sappemeer waste paper. Experiment 1 was carried out with stirring with 400 kU laccase and 10 g TEMPO per kg waste paper pulp in buckets without baffles. The oxidation increased the COOH content by 0.2% and the CHO content by 0.37%. The dry tear length was 105% of the background, the wet tear length was 169%, and the tear / tear work was 130%. Oxidation in Run 2 with 400 ku laccase and 50 g TEMPO per kg waste paper pulp in buckets without baffles gave increases of 0.51% COOH and 0.47% CHO. The values for dry-break length and tear / tear work were better with 121% and 139% than in test 1, the increase in wet-break length is still acceptable.

IV. Determination of drainage and retention properties:

In the following experiments, the properties of fibrous compositions according to the invention are compared with non-inventive fibrous compositions in which the oxidized waste paper pulp contained in the compositions according to the invention has been replaced by conventional waste paper pulp. The retention properties total retention and ash retention were compared using the Britt Jar test method Tappi T-261. In addition, the drainage time EWZ (according to ISO standard 5276) was determined.

The oxidized pulp used for these experiments was prepared by oxidation of conventional waste paper stock (Hoya) according to the procedure for Experiment 1, varying the amounts of laccase (Trametes versicolor, 250 U) and TEMPO in the manner indicated in Table 4:

Table 4

Try Laccase TEMPO COOH

CHO [mmol / kg] [wt%]> [wt%]> [mmol / kg]

3 2.0 0.00 96 28.7

4 2.0 0.05 100-200 ^* 28.9 Try Laccase TEMPO COOH

CHO [mmol / kg] [wt%]> [wt%]> [mmol / kg]

5 2.0 0.20 100-200 ^* 34.9

6 2.0 0.40 100-200 ^* 54.8

1) based on 1 kg waste paper pulp

^* Based on measured value inaccuracy, an estimated value based on the measured data Examples 1 to 4, Comparative Examples 1 to 3

In the following examples, a mixture of groundwood HS, pine sulphate pulp ZS and recycled paper pulp DIP or oxidized waste paper pulp DIP (E) from trials 3 to 6 (DIP (E3) to DIP (E6)) was used together with precipitated calcium carbonate (PCC) Diluted with a substance concentration of 0.5% and in the test apparatus with

Stirred at 1000 rpm. To this was added the fixing aid (polyethyleneimine, Catiofast SF, BASF SE) and dosed after 60 sec. the retention aid (polyvinylamine, polymin PR 8247, BASF SE). After 20 sec. a white water sample was taken to determine the total retention and the ash retention.

The EWZ dewatering time was determined according to ISO Standard 5276 using a Schopper-Riegler tester, by dewatering 1 liter of an aqueous slurry of the fiber composition to be tested with a consistency of 10 g / l in the apparatus and determining the time in seconds required for the Pass of 400 ml of filtrate were needed.

The starting materials and amounts as well as the results are summarized in Table 5:

Table 5

Example V1 V2 V3 1 2 3 4

HS [% by weight]> 50 50 50 50 50 50 50

DIP [wt%]> 40 40 40 40 (E3) 40 (E4) 40 (E5) 40 (E6)

ZS [wt .-%]> 10 10 10 10 10 10 10

PCC [wt%]> 50 50 50 50 50 50 50

Laccase [wt% @ ws] ² > 2.0 2.0 2.0 2.0

TEMPO [wt% @ ws] ² > 0.00 0.05 0.20 0.40

Polymin [wt% @ ws] ³ > 0.04 0.04 0.04 0.04 0.04 0.04

Catiofast [wt% @ ws] ³ > 0.10 0.10 0.10 0.10 0.10

EWZ 400 mL [sec] 53 20 18 17 18 17 16

Britt DJ - FPR [%] 43.3 62.1 64.6 66.8 67.0 67.7 68.2 Example V1 V2 V3 1 2 3 4

Ash- FPAR [%] 7.0 41.4 45.1 48.8 48.3 49.7 51.5

1) based on the total fiber mass

2) based on the fiber mass in the oxidation

3) based on the fiber suspension

Claims

claims:

A pulp composition for paper or board production, comprising a) at least one chemical pulp A and

b) at least one oxidized pulp B into which 1 to 500 mmol carboxyl groups and 1 to 200 mmol aldehyde groups per kg of conventional pulp have been introduced by oxidation of at least one conventional pulp selected from waste paper pulp, mechanical pulp and blends thereof, and

c) at least one further conventional pulp C other than A and B;

wherein the total amount of components A and B is from 30 to 80% by weight of the total pulp in the pulp composition, and ingredients A, B and C constitute at least 70%, especially at least 80% by weight of the total pulp in the pulp composition , each calculated as oven-dry substance.

A pulp composition according to claim 1, wherein the molar ratio of the introduced aldehyde groups to the introduced carboxyl groups in the oxidized pulp is not more than 1: 1.

A pulp composition according to any one of the preceding claims, comprising the oxidized pulp B and the pulp C in a total amount of from 70 to 98% by weight, based on the total weight of pulp in the pulp composition.

A pulp composition according to any one of the preceding claims, wherein the oxidized pulp constitutes at least 50% by weight, based on the total amount of oxidized pulp B and chemical pulp A.

A pulp composition according to any one of the preceding claims, wherein the oxidized pulp is selected from an oxidized waste paper pulp.

A pulp composition according to any one of the preceding claims, wherein the pulp C is selected from conventional mechanical and thermomechanical pulp and conventional waste paper pulp.

A pulp composition according to any one of the preceding claims, wherein the oxidized pulp is obtainable by oxidation of a conventional pulp with oxygen in the presence of a laccase.

The pulp composition of claim 7, wherein the oxidation is additionally carried out in the presence of a redox mediator.

The pulp composition of claim 8, wherein the redox mediator is a hindered amine oxide compound.

10. A pulp, wherein the fiber components are a pulp composition according to any one of claims 1 to 9. 1 1. Paper or board based on a pulp composition according to one of claims 1 to 9.

12. A method of making a paper or paperboard comprising

i) preparing an aqueous pulp suspension containing

a) at least one chemical pulp A and

b) at least one oxidized pulp B into which 1 to 500 mmol of carboxyl groups and 1 to 200 mmol of aldehyde groups per kg of conventional pulp have been introduced by oxidation of at least one conventional pulp selected from waste paper pulp, mechanical pulp and mixtures thereof, and c) at least one further, different conventional pulp C from A and B;

comprising suspending the pulps in water and optionally adding conventional additives and fillers, and

ii) dewatering the pulp suspension in a paper machine to form paper or cardboard,

wherein the relative amounts of the pulps are selected so that the total amount of the components A and B is from 30 to 80% by weight of the total pulp in the pulp suspension and the total amount of the components A, B and C is at least 70% by weight make up the entire pulp in the pulp composition, each calculated as oven-dry pulp.

13. The method of claim 12, wherein the molar ratio of the introduced aldehyde groups to the introduced carboxyl groups in the oxidized pulp is not more than 1: 1.

14. The method of claim 12 or 13, wherein the oxidized pulp B and the pulp C make up 70 to 98 wt .-% of the total mass of pulp in the pulp suspension, each counted as oven-dry material.

A method according to any of claims 12, 13 or 14, wherein the oxidized pulp constitutes at least 50% by weight, based on the total amount of oxidized pulp B and chemical pulp A in the pulp suspension. 16. The method according to any one of claims 12 to 15, wherein the oxidized pulp is selected from oxidized waste paper pulp.

17. The method according to any one of claims 12 to 16, wherein the pulp C is selected from conventional mechanical and thermomechanical pulp and conventional waste paper pulp.

18. The method of claim 12, wherein the paper is a writing or printing paper. 19. The method according to any one of claims 12 to 17, wherein the paper is a packaging paper.

20. The method according to any one of claims 12 to 17, wherein it is cardboard (solid board).

21. Use of an oxidized pulp B into which 1 to 500 mmol of carboxyl groups and 1 to 200 mmol of aldehyde groups per kg of conventional pulp have been introduced by oxidation of at least one conventional pulp selected from waste paper pulp, mechanical pulp and blends thereof to improve the retention properties of pulp compositions for the paper - or board production, which contain at least one chemical pulp and at least one further, selected from mechanical, chemomechanical and conventional waste paper pulp fabric. 22. Use according to claim 21, wherein the oxidized pulp is selected from oxidized waste paper pulp.