RU2573675C2 - Freeness of paper products - Google Patents

Abstract

FIELD: textiles, paper.

SUBSTANCE: invention relates to a method of processing the pulp suspension, comprising (i) a step of exposure to cellulose fibres of the aqueous solution of manganese catalyst of transition metal and hydrogen peroxide at a pH of 6-13, and (ii) grinding the pulp to achieve the value of Schopper-Riegler (SR) of 10-90° and recycling the resulting mass in a paper, cloth or cardboard, at that the manganese catalyst of transition metal is present in a concentration of 0.0001-1 kg/ton of absolutely dry pulp and hydrogen peroxide is present at a concentration of 0.1-100 kg/ton of absolutely dry pulp, manganese catalyst of transition metal is preliminary prepared from mononuclear Mn(II), Mn(III), Mn(IV), or binuclear Mn(II)Mn(II), Mn(II)Mn(III), Mn(III)Mn(III), Mn(III)Mn(IV) or Mn(IV)Mn(IV) and the ligand of the transition metal of the formula (I):

where:

; p=3; R is independently selected from hydrogen, C1-C6-alkyl, CH₂CH₂OH, CH₂COOH, and pyridin-2-ylmethyl; R1, R2, R3 and R4 are independently selected from H, C1-C4 alkyl, C1-C4-alkylhydroxy. The invention also relates to the use of aqueous solution of the said manganese catalyst to increase the freeness of the pulp fibres during grinding.

EFFECT: optimisation of the mass processing conditions with the catalyst and hydrogen peroxide to obtain a value of freeness (SR) of fabric made from the processed pulp, such that the energy required for mechanical mixing the mass is reduced.

25 cl, 3 tbl

Description

FIELD OF THE INVENTION

The present invention relates to a new method of processing paper pulp.

Prior art

Pulp for the production of paper, fabric, cardboard or products thereof can be obtained from cellulose of wood and other sources (for example, hemp, straw, cotton). In the vast majority of cases, the raw material is wood pulp, which can be raw material from coniferous and deciduous species. Softwood fibers are obtained from needle-bearing conifers, such as pine, spruce, alpine fir, Douglas spruce. Hardwood fibers are obtained from deciduous trees of various types, such as birch, eucalyptus and acacia. Wood pulp contains most of the original lignin, while in pulp most of the lignin is removed.

Among the notable differences between softwood (SW) and hardwood (HW) fibers are the length of individual cellulosic fibers, fiber roughness, and fiber stiffness / shrinkability.

Soft and hard wood must be subjected to certain mechanical processing (grinding) to turn the wood into a fibrous suspension used in the formation of paper web. The fibers in the cellulose suspension are machined to change the properties of the fibers. The cellulose suspension is processed into a product with an increased tensile strength / tensile strength, an increased Chopper-Riegler grinding degree (dryness), increased purity and improved paper / fabric manufacturing properties compared to the original cellulose suspension. An increase in the freeness of grinding results in a decrease in dehydration in the manufacture of paper / fabric, which increases the energy required to dry the paper, and this will slow down the speed of paper production. Too low a creep, on the other hand, gives paper / fabric that is not strong enough. Grinding is of great importance for the chemical and mechanical properties of cellulose. In addition to dehydration, it should also be noted that energy consumption during the grinding process is high.

A chemical process to modulate cellulosic fibers by treating the fibers with iron salts and hydrogen peroxide is disclosed in WO 2005/028744; treating softwood kraft pulp results in fiber properties resembling those of hardwood fiber.

WO 2004/022842 discloses a process with reduced energy consumption for grinding wood pulp after treatment with pectinase enzyme for the production of cellulose with a certain hardening.

EP 0458397 discloses the use of complexes of 1,4,7-trimethyl-1,4,7-triazacyclononane Mn (Me ₃ -TACN) as bleaching and oxidation catalysts and use in the process of bleaching textiles and pulp.

US 2001/0025695 A1, Patt et al., Discloses the use of ClO ₄ ^- and PF ₆ ^- salts of complexes of manganese 1,2-bis- (4,7, -dimethyl-1,4,7, -triazacyclonon-1-yl) -ethane (Me ₄ -DTNE) and Me ₃ -TACN, respectively, for delignification and bleaching of wood pulp. While the decrease in viscosity when using a manganese compound containing Me ₄ -DTNE is absent or slightly, the decrease in viscosity when using a manganese compound containing Me ₃ -TACN is much greater, it is known that cellulose with a lower viscosity gives paper with reduced strength ( (Pulp Bleaching, Principle and Practice (CWDence, DWReeve ed., Tappi, Atlanta, 1996).

WO 2007/125517 discloses the use of 1,2-bis- (4,7, -dimethyl-1,4,7, -triazacyclonon-1-yl) -ethane (Me ₄ -DTNE) and Me ₃ -TACN with buffer and complexing agents for bleaching cellulose substrates.

WO 2008/086937 discloses the use of 1,2, -bis- (4.7, -dimethyl-1,4,7, -triazacyclonon-1-yl) -ethane (Me ₄ -DTNE) and Me ₃ -TACN for bleaching cellulose substrates while maintaining a constant pH.

US 2002/0066542 A1 describes complex compounds of a transition metal, in particular cobalt, with polydentate ligands and the use of such compounds in delignification and bleaching processes. Comparative experiments conducted with a complex of manganese, including Me ₃ -TACN, showed a noticeable loss of viscosity, while the other compounds described do not give significant changes in viscosity.

It was of interest to create a method that allows paper / fabric manufacturers to use a lower creep grinding process that produces pulp with the same strength properties that are typically achieved by mechanical means.

SUMMARY OF THE INVENTION

The authors found that treatment of cellulose fibers using a preformed transition metal complex with azacyclic molecules and hydrogen peroxide improves the effect of grinding these fibers. Processing may be performed before, during or after the grinding process, typically before or during the grinding process. Improved grinding properties can be observed in the form of increased tensile strength at the same cost of mechanical energy and the same Schopper-Riegler (SR) value.

In addition, despite the fact that in the pulp and paper industry it is believed that a significant reduction in the loss of viscosity of cellulose is undesirable in the manufacture of paper and that the use of manganese catalysts containing Me ₃ -TACN, gives a significant loss of viscosity according to various studies, especially It was surprising to discover that the use of such catalysts leads to an improvement in the effect of the grinding process on the properties of the fiber.

The present invention can be applied to chemical and mechanical pulp, including pulp for the production of paper, fabric or cardboard.

The authors found that energy consumption and the preparation time of a suspension of cellulose, which can then be processed into a web with improved creep, can be reduced by the action of a manganese catalyst along with hydrogen peroxide.

In a first aspect, the present invention provides a method for treating a cellulose suspension, comprising (i) a step of exposing the cellulose fibers to an aqueous solution of a manganese transition metal catalyst and hydrogen peroxide at pH 6-13; and (ii) grinding the cellulose to achieve a Shopper-Riegler (SR) value 10-90 ° and the resulting cellulose is processed into paper, fabric or cardboard, moreover, the manganese transition metal catalyst is present in a concentration of 0.0001-1 kg / t of absolutely dry cellulose and hydrogen peroxide is present in a concentration of 0.1-100 g / t of absolutely dry cellulose, a manganese transition metal catalyst is preliminarily prepared from mononuclear Mn (II), Mn (III), Mn (IV) or dual-core Mn (II) Mn (II), Mn (II) Mn (III), Mn (III) Mn (III), Mn (III) Mn (IV) or Mn (IV) Mn (IV) and a transition metal catalyst ligand based on a transition metal of formula (I):

,

,

;where: Q =

;

p is 3;

R is independently selected from hydrogen, C1-C6 alkyl, C ₂ OH, C ₁ COOH and pyridin-2-ylmethyl, or one of R is bonded to N of the other Q from the other ring by an ethylene bridge;

R1, R2, R3 and R4 are independently selected from H, C1-C4 alkyl, C1-C4 alkyl hydroxy.

In a second aspect, the invention relates to the use of an aqueous solution of a manganese transition metal catalyst and hydrogen peroxide at pH 6-13, in which a manganese transition metal catalyst of mononuclear Mn (II), Mn (III), Mn (IV) or a dual core Mn is preliminarily prepared. (II) Mn (II), Mn (II) Mn (III), Mn (III) Mn (III), Mn (III) Mn (IV) or Mn (IV) Mn (IV) and a ligand of the formula (I):

,

,

;where: Q =

;

p is 3;

R is independently selected from hydrogen, C1-C6 alkyl, C ₂ OH, C ₁ COOH and pyridin-2-ylmethyl, or one of R is bonded to N of the other Q from the other ring by an ethylene bridge;

R1, R2, R3 and R4 are independently selected from H, C1-C4 alkyl, C1-C4 alkyl hydroxy,

to increase the degree of fiber creepiness of the pulp in the milling process.

In accordance with specific embodiments of the first and second aspect of the invention, each R in the ligand of formula (I) is independently selected from hydrogen, C1-C6 alkyl, C ₂ OH, C ₁ COOH, and pyridin-2-ylmethyl. Particularly unexpected for these non-bridging ligands, in which R is not connected by an ethylene bridge to N of another Q from another ring, is that they are suitable for use in accordance with the method of the present invention, due to the discovery in the prior art of reducing the viscosity established by carrying out delignification reactions using transition metal catalysts including such ligands.

In a further aspect, the invention provides paper, fabric, or paperboard obtainable by a method in accordance with a first aspect of the invention, or use in accordance with a second aspect of the invention.

The creep value (SR) is determined by the standard definition of dryness by the Schoper-Riegler method NORM EN ISO 5267-1; the freeness value (SR) used in the invention is measured by this method.

The concentration of the catalyst and hydrogen peroxide will affect the time required for grinding the mass, depending on the ratio of the mass weight to the amount of active substance used. In this regard, to optimize the conditions, the variable concentrations of the active substance, temperature, pH and time can be changed.

The processing time of the mass with the catalyst and hydrogen peroxide is preferably from 1 minute to 4 hours, more preferably from 5 minutes to 3 hours, and most preferably from 10 minutes to 2 hours. In addition, the temperature of the process using the catalyst and hydrogen peroxide is preferably 30-95 ° C and more preferably 40-90 ° C. The pH of the process using a catalyst and hydrogen peroxide is preferably 8-12.

The transition metal complex and hydrogen peroxide can be added in the normal bleaching step. In addition, the transition metal complex and hydrogen peroxide can be added before or during the grinding step, for example, to a mass that has already been bleached at one or more stages of delignification and bleaching, i.e. to chemical mass. The chemical mass thus treated can be delignified / bleached by contact with hydrogen peroxide and a transition metal catalyst, for example, in accordance with the present invention. Alternatively, the chemical mass can be prepared in a different way, for example, by non-catalytic bleaching of the mass, for example, using ozone, chlorine dioxide or non-catalytic bleaching with hydrogen peroxide.

Alternatively, the manganese catalyst together with hydrogen peroxide can be used in the bleaching step and again after the bleaching step, before or during the grinding step.

Often, a bleaching step is carried out to treat the mechanical and secondary pulp, for example, including the use of hydrogen peroxide. In such cases, a manganese transition metal catalyst, determined in accordance with the first and second aspects of the invention, may also be included. Sometimes a reductive bleaching stage with dithionite can be used to process the secondary mass (no manganese transition metal catalyst will be added at this bleaching stage). Alternatively, the manganese transition metal catalyst and hydrogen peroxide can be used to treat the mechanical mass and the secondary mass, in particular, before or during the mechanical grinding process, then it is bleached with hydrogen peroxide and / or dithionite.

Alternatively, the manganese catalyst together with hydrogen peroxide can be used both at the bleaching stage and again after the bleaching stage, before or during the grinding stage.

These features are discussed in more detail below. The washing step is usually, but not necessarily, between the addition of a transition metal catalyst and hydrogen peroxide and a grinding process (if the former is carried out to the latter). It should be noted that the amount of transition metal / hydrogen peroxide catalyst required per tonne of mass (absolutely dry) is essentially determined by molar ratios, but the representation of weight amounts is normal in industry. In this regard, the range of amounts of transition metal catalyst required per tonne of mass (absolutely dry) is 0.0001-1 kg per tonne of mass (absolutely dry), which is approximately equivalent to 0.1-1500 mmol / tonne of mass (absolutely dry) . In accordance with specific embodiments of the invention, the concentration of the transition metal catalyst is 0.0005-0.2 kg per tonne of mass (absolutely dry). The content of hydrogen peroxide (100%) per tonne of mass (absolutely dry) is 0.1-100 kg, more preferably 0.5-50 kg, most preferably 1-30 kg. For example, the content of hydrogen peroxide (100%) per tonne of mass (absolutely dry) can be 0.1-25 kg per tonne of mass (absolutely dry). It should be understood that each of the ranges of concentration of the transition metal catalyst described in the invention can be combined with each of the ranges of hydrogen peroxide content described in the invention. For example, according to some embodiments of the invention, the concentration of the transition metal catalyst is 0.0005-0.2 kg per tonne of mass (absolutely dry) and hydrogen peroxide (100%) per tonne of mass (absolutely dry) 0.1-25 kg.

The molar ratio of the transition metal catalyst: hydrogen peroxide is preferably 1: 100-1: 10000.

In view of the foregoing, it is common for a person skilled in the art to determine conditions by trial and error to obtain a sage value (SR) and apply conditions to obtain and optimize a mass with a desired sag value (SR) in the fabrication.

The implementation of the invention

The mass for the production of varietal paper or paperboard is fed into a paper machine, where a paper web is formed and water is removed from it by pressing and drying. Pressing the sheet removes water by extrusion. Felt is used to remove water from the water collection sheet. In the manufacture of paper manually use a sheet of blotting paper. The mass for the production of varietal fabric or kitchen towels is dehydrated and dried without pressing to maintain appropriate absorbent properties and roughness.

Drying involves the use of air and / or heat to remove water from a sheet of paper. Previously, in the manufacture of paper, drying was carried out by hanging sheets of paper as in a laundry. Currently, various forms of drying mechanisms are used. In a paper machine, the most common is a steam-heated tumble dryer. These dryers can be heated to temperatures above 200 ° F (93 ° C), using a long row of more than 40 drums. The heat they produce can easily dry the paper to less than 6% moisture.

There are certain methods for the production of paper napkins. Reference may be made to Paper and Board Grades, Book 18, chapter 4, by the Finnish Paper Engineers' Association and TAPPI (2000).

The authors found that treating a suspension of cellulose pulp with a manganese transition metal catalyst and hydrogen peroxide changes the degree of impact on the mass of the mechanical grinding process, by measuring the creep value (Shopper-Riegler - SR), to obtain a web made from the suspension of mass. Processing with a manganese catalyst can be carried out before mechanical grinding, during or after the mechanical grinding process. For example, and as discussed below, hydrogen catalyst / peroxide can be added to the pulp mixture or pulp tank after mechanical grinding, where the pulp can be stored until dehydration.

The relationship between tensile strength and creep is improved, i.e. either increased strength with the same creep value or the same strength with less creep. By monitoring the processing conditions, the optimum value of the final product is obtained. In addition, an increased volume can be achieved with the same grinding, which is especially important for paper for sanitary purposes.

We have found that treating the pulp suspension and controlling the concentration and time variables provides the optimum value of creep for different periods of time.

The term “absolutely dry mass” refers to a mass dried at a temperature of 100-105 ° C. to a constant weight. See TAPPI-test T240 OM-93 (1993).

Grinding

Various types of equipment are often used for machining pulp. Many plants previously used grinding machines, including the Dutch threshing drum, but now they are largely replaced by conical and disk grinders that can work in a continuous process. There are cone shredders with a small angle (Jordan), medium angle (Conflo) and wide angle of sliding (Claflin). The group of disk shredders includes three types, single-disk, double-disk, multi-disk shredders.

Grinding can be carried out at low concentration (2-6%), medium concentration (10-20%) or high concentration (30-35%). Depending on the requirements for the final product, various optimal concentrations for processing can be selected. See Paper and Board Grades, Papermaking Part 1. Stock Preparation and Wet End, Book 18, chapter 4, by the Finnish Paper Engineers' Association and TAPPI (2000).

The processes can be carried out either in batch or continuous mode, the latter often being preferred for economic reasons and easier quality control.

In many cases, various types of wood pulp are mixed, for example, coniferous and deciduous cellulose. One of them or both can be ground separately. Often, a larger number of shredders are used sequentially to increase profit / energy consumption for mass processing.

Grinding can take place in the case of chemical pulp, mechanical and pulp pulp and all are the purpose of the present invention.

Depending on the application, grinding of various degrees can be performed. For the variety, the fabric and kitchen napkin are milled to a low degree to ensure good volume, softness, absorbency and whiteness. A low degree of grinding is advisable to achieve the above properties, but adversely affects the strength properties. Therefore, agents are often added to increase strength in the wet and / or dry state. Often after processing Shopper-Riegler values of 10-30 ° are obtained.

Key parameters for printing and writing paper are suitability for printing and operability of the machine. The paper should be clean and white, have the appropriate smoothness, compressibility, absorbency of the printing ink and sufficient strength for printing. Minimum opacity is another important feature. Thus, these types of paper require good grinding control to enhance the strength of the internal bonds and obtain the required level of smoothness and clearance for their end use. The bleached paperboard grades used to pack frozen foods and liquids and / or paper plates and cups require good stiffness and volume with proper smoothness and printability. Also, the internal bond of the fibers, paper bending resistance and dimensional stability are important factors. Therefore, sufficient grinding will also be necessary to obtain these properties (without too much reduction in volume and stiffness). For these applications, Shopper-Riegler 15-50 ° values are often required after grinding.

Thick paper requires significant grinding depending on the specific product requirements. Laying paper, glassine, and greaseproof paper require deep grinding to obtain the desired balance of strength and appearance. In particular, if the goal is to produce transparent paper, significant energy will be required for the grinding processes. High SR values such as 90 ° may be required.

Mechanical pulp often requires grinding to produce paper or paperboard materials with appropriate physical properties. When grinding wood pulp, Shopper-Riegler values of 20-80 ° are often achieved.

The degree of grinding can be controlled online. Power consumption is the most important parameter for determining the degree of grinding. There are control systems for online monitoring of the grinding process and adjusting energy consumption in accordance with the requirements. The probes monitor the chopper loading, temperature changes, flow rate / concentration, dehydration / dryness (SR), etc. Key process parameters include temperature, pH, concentration, additives, pre-treatment, productivity and energy consumption.

Treatment of cellulose fibers with manganese catalyst and hydrogen peroxide

The use of a manganese catalyst and hydrogen peroxide for treating cellulosic fibers can be performed at various stages of the fiber processing / papermaking process. It can take place before the mechanical grinding process, during the mechanical grinding process or after the mechanical grinding process, typically before or during the mechanical grinding process.

Typically, a pulp that has been bleached at one or more stages of delignification and bleaching, the chemical mass can be used for further processing to obtain fabric, paper or cardboard. However, lignin-containing pulp (wood pulp) or waste paper pulp can also be used in the framework of the present invention. In integrated plants, the wet slurry of the pulp is sent to a paper mill. When papermakers receive pulp from other plants, the pulp is first placed in a tank and crushed to obtain a diluted suspension of pulp, which can be processed further.

In paper mills, the chemical pulp is usually bleached with hydrogen peroxide and / or other bleaching processes using, for example, ozone or chlorine dioxide. The mechanical and waste mass is often bleached with hydrogen peroxide to increase the whiteness of the mass. During one or more of these bleaching stages, hydrogen peroxide together with a manganese catalyst can be used to produce cellulose, which can be processed by the grinding process. Manganese catalyst and hydrogen peroxide can be added during various stages in a paper mill.

In the mass mixer, chemicals are added to the mass, which is then mixed very thoroughly. In the framework of this invention, a catalyst and hydrogen peroxide can be added to the mass mixer to complete the processing of the mass. This can be done in a low concentration mixer (continuous mixers, tower mixers, dynamic or static mixers), a medium concentration mixer (pin mixers, high shear mixers) or a high concentration mixer, including a knider and disc type mixer. In a steam jet mixer, steam is added to the mass to increase the temperature of the mass. The catalyst and hydrogen peroxide can also be added to the mass in a steam jet mixer. (See Pulp Bleaching, Principle and Practice, C.W. Dence, D.W. Reeve ed., Tappi, Atlanta, 1996, infra.)

After adding chemicals to bleach the pulp into the mixers, most of the pulp is bleached in the pulp bleaching tower, after which the pulp is washed. Since bleaching processes are usually slow (usually 2-4 hours), bleaching towers are usually large. However, sometimes tubes with less mass retention are also used, so that some bleaching or processing reactions take place. Since the processes are usually continuous, the mass slowly moves either up (tower with an upward flow), down (tower with a downward flow) or with their combination (tower with an upward-downward flow). In the framework of this invention, the treatment with the catalyst and hydrogen peroxide can be much shorter, which allows the use of relatively small treatment towers.

In a mass washer, the mass treated with chemicals at the previous stage of the processing process is usually washed. For example, acid chlorine dioxide is washed with a NaOH solution to remove lignin residues soluble in alkali and to obtain a mass ready for the next step. In the framework of this invention, manganese catalyst and hydrogen peroxide can be added to the (optional) mixer using their fast reaction kinetics to treat the mass of the catalyst.

The mass storage tower is designed to store mass for subsequent processing after a certain period of time. Typically, such storage towers can be found prior to processes that undergo pulp bleaching stages or after the final bleaching stage, for example, before being transported to a paper mill. The catalyst and hydrogen peroxide can be added together with the mass introduced into this tower for storage, providing a slow process of processing the mass.

The hydraulic diluent is used to dilute waste paper (ennobled pulp) and to add alkali and hydrogen peroxide to whiten the ennobled pulp. Manganese catalyst may be added to this hydraulic diluent to allow the catalyst to treat the treated pulp.

Also, manganese catalyst and hydrogen peroxide can be added to the pulp before the milling process in a paper mill, for example, in a pulp mill, a high density mass pool, a holding pool, a mixing basin or a mass pool to even out the mass concentration. A pulper and a mass pool with a high mass density are usually used to prepare dry raw materials, half mass and recycled paper in a condition suitable for pumping by adding water and then mixing with water. In a mixing basin, two or more different types of pulp, optionally ground, mixed and stored for further processing, for example, coniferous and deciduous cellulose. In the mass pool, to equalize the mass concentration, the wood pulp concentration is reduced to the desired level.

The mechanical mass is often processed in holding pools for processing deformed fibers (broken, twisted or woven). Typically, the mechanical mass is diluted to a concentration of 1-2%, heated to 70-90 ° C, stirred for at least 20 minutes, after which further processing is carried out. Mass pools for storing pulp, like the storage of pulp described above, are used for storing wood pulp. Also, the other above mentioned basins are often used for storing wood pulp and ensuring a constant flow of pulp processed in subsequent processes. Wood pulp can be shipped from a bleached pulp mill, or it can be produced locally (a plant using its own raw materials).

Alternatively, a catalyst / hydrogen peroxide can be added directly upstream of the chopper and will react with cellulose during the milling process. Due to the heat generated during milling, additional energy consumption to reduce the catalyst treatment effect will be reduced or absent. Various grinding equipment can be used, which includes grinding machines; Dutch threshing drums; cone shredders with a small angle, medium angle and wide angle of sliding; single-disc, double-disc, multi-disc. See Paper and Board Grades, Papermaking Part 1. Stock Preparation and Wet End, Book 18, chapter 4, by the Finnish Paper Engineers' Association and TAPPI (2000) and C.F. Baker, Tappi Journal, 78, 147, 1995.

Finally, the hydrogen catalyst / peroxide can be added after the mechanical grinding step, for example, in a metal pool (where various sources of wood pulp are mixed) or a mass pool for storing the mass. For example, wood pulp can be processed this way.

Alternatively, the manganese catalyst together with hydrogen peroxide can be used both at the bleaching stage and repeatedly after the bleaching stage, before or during the grinding stage.

Transition Metal Catalyst

The manganese transition metal catalyst used may be non-hygroscopic with counterions such as PF ₆ ^- or ClO ₄ ^- . However, for industrial substrates, it is preferred that the transition metal complex dissolves in water. Preferably, the preformed transition metal catalyst is in the form of a salt whose solubility in water is at least 30 g / L, for example at least 50 g / L at 20 ° C. Preferred salts are chloride, acetate, sulfate and nitrate. These salts are described in WO 2006/125517.

In accordance with certain embodiments of the invention, each R in the ligand of formula (I) is independently selected from hydrogen, C1-C6 alkyl, C ₂ OH, C ₁ COOH and pyridin-2-ylmethyl. In accordance with certain embodiments, R is independently selected from hydrogen, CH ₃ , C ₂ H ₅ , CH ₂ CH ₂ OH, and CH ₂ COOH.

R1, R2, R3 and R4 are preferably selected independently from H and Me.

In accordance with certain embodiments, R, R1, R2, R3, and R4 are independently selected from H and Me. Most preferably, the catalyst is derived from 1,4,7-trimethyl-1,4,7-triazacyclononane (Me ₃ -TACN).

The preformed salt metal transition metal catalyst is preferably a binuclear Mn (III) or Mn (IV) complex with at least one O ² bridge. According to some embodiments of the invention, the transition metal catalyst may be a salt, such as the salts described above, of the complex [Mn (IV) ₂ (µ-O) ₃ (Me ₃ TaCN) ₂ ] ²⁺ .

The amount of manganese catalysts used may vary depending on the application, but is usually 0.0005-0.2 kg / t absolutely dry weight (o.d.p.).

Hydrogen peroxide

Hydrogen peroxide is used directly in the form of an aqueous solution or salts of acid, such as percarbonate, etc. However, for economic reasons, liquid hydrogen peroxide is preferred. The preferred amount of hydrogen peroxide used is: 0.1-100 kg / t absolutely dry weight (o.d.p.), more preferably 0.3-50 kg / t o.d.p. and most preferably 0.5-25 kg / t o.d.p.

The reagents are preferably used in an alkaline environment, optimally at pH 8-13, the alkalinity of which is preferably created by sodium hydroxide or sodium carbonate.

The temperature of the processing process is preferably 30-95 ° C. And more preferably 40-90 ° C.

The processing time of the catalysts and hydrogen peroxide is from 1 minute to 4 hours, more preferably from 5 minutes to 3 hours, and most preferably from 10 minutes to 2 hours.

Complexing agent

Many complexing agents are suitable for use in the present invention. Examples include aminophosphonates and carboxylates as complexing agents, for example, aminophosphonates and aminocarboxylate complexing agents. Suitable complexing agents include ethylene diamine tetra acetate (EDTA), polyphosphonates such as DequestTM and non-phosphate stabilizers such as EDDS (ethylenediamine di-succinic acid).

The complexing agent used in the treatment step with a manganese catalyst and hydrogen peroxide is preferably an aminocarboxylate complexing agent or mixtures thereof. The following are preferable examples of aminocarboxylate complexing agents: ethylenediaminetetraacetic acid (EDTA), N-hydroxyethylenediaminetetraacetic acid (HEDTA), iminodiuccinic acid (IDS), nitrilotriacetic acid (NTA), N-hydroxyethylaminodiacetic acid (DM) di-diacetic acid (di) acetic acid (MG) di-diacetic acid, di-diacetic acetic acid ethylenediamine di-succinic acid (EDDS) and alanine-N, N-diacetic acid. The most preferred aminocarboxylate complexing agent is diethylene triamine pentaacetic acid (DTPA).

Phosphonate complexing agents may also be used; the preferred phosphonate complexing agent is Dequest 2066 (sodium salt of diethylene triamine penta (methylene phosphonic acid).

It should be borne in mind that in case of use, complexing agents may be present in the form of a free acid or salt. For example, if the complexing agent is present in the form of a salt, it may be a salt of alkali metals, alkaline earth metals, ammonium or substituted ammonium. Typically, if present, the complexing agent is in the form of a free acid or in the form of a salt of sodium, potassium or magnesium. An example of a sodium salt of an aminocarboxylate complexing agent is diethylene triamine penta (methylenephosphonic acid) penta sodium salt, commercially available under the trademark Dequest 2066A.

The most preferred complexing agent concentration used in the method is 0.01-50 kg / ton absolute dry weight in a solution containing manganese catalyst and hydrogen peroxide, most preferably 0.03-20 kg / ton absolute dry weight.

experimental part

Experiment 1: Treatment of softwood pulp with hydrogen peroxide in the presence and absence of [Mn ₂ (µ-O) ₃ (Me ₃ TACN) ₂ ] (CH ₂ COO) ₂ at pH 11.0 (Me ₃ -TACN = 1.4, 7-trimethyl-1,4,7-triazacyclononan).

[Mn ₂ (µ-O) ₃ (Me ₃ TACN) ₂ ] (CH ₃ COO) ₂ (as a 3.5% aqueous solution) was prepared as described in (WO 2006/125517).

Softwood pulp with an initial ISO-optical brightness of 49.9 is processed as follows: in a polyethylene (PE) container containing 250 g of absolutely dry cellulose with a 10% concentration, add 10 kg / odtp H ₂ O ₂ (odtp = ton of absolutely dry cellulose - equal to 29.4 mmol H ₂ O ₂ ) and 7.2 kg / odtp NaOH (equal to 18 mmol NaOH). Depending on the experiments, add 0.04 kg / odtp [Mn ₂ (µ-O) ₃ (Me ₃ TACN ₂ ] (CH ₃ COO) ₂ (equal to 6.5 micromoles [Mn ₂ (µ-O) ₃ (Me ₃ TACN ₂ ] (CH ₃ COO) ₂ and 1.0 kg / odtp DTPA (pentasodium salt of diethylene triamine pentaacetic acid) - (ex Akzo Nobel; trade name Dissolvine D50, purity 50%). The initial pH value is 11.0 (at 20 ° FROM).

Note 1: This softwood pulp is delignified in the O ₂ delignification step and then partially bleached in the ClO ₂ step.

Note 2: In practice, cellulose is used, which contains 35.6% dry matter and 64.4% water (35.6% dry matter). Therefore, 702.3 g of “wet” cellulose is used in each experiment.

Note 3: All experiments are carried out at 10% concentration.

PE containers are placed in a pre-heated water bath (62.5 ° C) for 1 hour and shaken during bleaching. Then the cellulose mixture is filtered through a Buchner funnel and washed with a large amount of demineralized water. The flow rate of H ₂ O _{2 is} measured using the filtrate. The following analyzes are carried out on bleached pulp: Kappa number, brightness and intrinsic viscosity.

The experimental results are shown in table 1.

Table 1 Processing results of softwood pulp using [Mn ₂ (µ-O) ₃ (Me ₃ TACN) ₂ ] (CH ₃ COO) ₂ , [Mn ₂ (µ-O) ₃ (Me ₃ TACN) ₂ ] (CH ₃ COO) ₂ and DTPA and without [Mn ₂ (-O) ₃ (Me ₃ TACN) ₂ ] at an initial pH of 11.0 at 60 ° C for 60 minutes No. ° Sample Brightness (ISO%) Int. viscous (mg / g) Kappa # H ₂ O ₂ consumption (kg / odtp) U Unprocessed (raw) 49.9 764 8.33 P1 Idle experience (no catalyst, no DTPA) 67.4 753 4.27 7.5 P2 0.04 kg / odtp [Mn ₂ (µ-O) ₃ (Me ₃ TACN) ₂ ] (CH ₃ COO) ₂ and 1 kg / odtp DTPA 68.1 701 4.11 7.8 P3 0.04 kg / odtp [Mn ₂ (µ-O) ₃ (Me ₃ TACN) ₂ ] (CH ₃ COO) 2 66.8 698 4.17 9.6

The results are collected in Table 1 demonstrate that the addition of [Mn ₂ (μ-O) ₃ (Me ₃ TACN) _2] (CH ₃ COO) ₂ has some effect in bleaching and kappa value and a clear effect on the viscosity (degree of polymerization pulp) softwood pulp.

The treated mass is crushed (DIN EN ISO 5263-1, 2004-12), milled (PFI grinder) (ONORM EN ISO 5264-2, 2003-05) and tested for draining (Shopper-Riegler method, ONORM EN ISO 5267-1, 2000-10). Laboratory castings are prepared using the Rapid-Kothen method (ONORM EN ISO 5269-2, 2005-04) and conditioning of samples NC 23/50 is carried out (DIN EN 20187, 1993-11). The following tests are carried out using castings: grammar (DIN EN ISO 536; 1996-08), thickness, filling and density (DIN EN ISO 534; 2005-05), air permeability (Bendtsen, ISO 5636/3, 1992-09) , tensile strength, elongation at break, tensile strength, tensile strength index, TEA and modulus of elasticity (DIN EN ISO 1924-2,2009-05), internal bond of paper fibers (z-direction, TAPPI 541 OM-05; 2005) , tear resistance, paper tensile strength coefficient (ONORM EN 21974, 1994-09). The results are shown in the following tables.

table 2 The results of the grinding of the mass and dryability of bleached softwood pulp after processing in accordance with the conditions shown in table 1 P1: no catalyst, no DTPA P2: [Mn ₂ (µ-O) ₃ (Me ₃ TACN) ₂ ] (CH ₃ COO) ₂ and DTPA P3: [Mn ₂ (µ-O) ₃ (Me ₃ TACN) ₂ ] (CH ₃ COO) ₂ without DTPA Sample
Drainability P1
[SR] P2
[SR] P3
[SR] Broom grinding 14.0 13.8 14.0 PFI 2000 rpm 15.9 16,2 16.9 PFI 5000 rpm 24.1 24.3 23,2 PFI 7000 rpm s 32,7 32.8 32.9 PFI 9000 rpm 41.6 46.5 45.5

The results collected in Table 2 show that samples of the mass treated with catalyst and hydrogen peroxide have similar SR values up to 7000 rpm as a reference, while increased SR values are obtained when the mass is milled at 9000 rpm.

Table 3 Strength and tensile strength of paper castings prepared using a mass milled at 5000 rpm, as shown in table 2 Sample P1 5000 r P2 5000 r P3 5000 r Grammage [g / m ² ] 80.2 81.0 80.2 Thickness [microns] 111 112 113 Density [g / cm ³ ] 0.724 0.725 0.711 Filling [cm ³ / g] 1,380 1,380 1,407 Air Permeability (Bendtsen) [ml / min] 429 435 560 Pull force [N] 101 111 108 Elongation at break [%] 2.96 2.89 2.89 Tensile strength [kN / m] 6.74 7.42 7.21 Tensile strength index [Nm / g] 84.1 91.6 89.9 Tea [J / m ² ] 136 144 141 Elastic modulus [GPa] 6.33 6.92 6.76 Interlocking Paper Fibers [N / cm ² ] 82.6 81.5 84.1 Tear resistance [mn] 877 827 814 Tear Resistance Coefficient [MH.m ² / g] 10.9 10,2 10,2

The results collected in table 3 show that the mass samples treated with catalyst and hydrogen peroxide and then grinding at 5000 rpm in a PFI grinder exhibit increased tensile strengths, tensile energy consumption (TEA) and tensile strength index values, reduced tear resistance and tensile strength index, while other parameters are largely independent of processing using a catalyst and hydrogen peroxide (all relative to the sample without catalyst - P1). The tensile strength is improved slightly when using the catalyst in combination with DTPA.

Claims (25)

1. A method of treating a suspension of pulp, comprising (i) the step of exposing the cellulose fiber to an aqueous solution of a manganese transition metal catalyst and hydrogen peroxide at pH 6-13; and (ii) milling the pulp to achieve a Shopper-Riegler (SR) value of 10-90 ° and processing the resulting mass into paper, fabric or cardboard, moreover, the manganese transition metal catalyst is present in a concentration of 0.0001-1 kg / ton of absolutely dry cellulose and hydrogen peroxide is present in a concentration of 0.1-100 kg / ton of absolutely dry cellulose, The manganese transition metal catalyst from mononuclear Mn (II), Mn (III), Mn (IV) or the dual core Mn (II) Mn (II), Mn (II) Mn (III), Mn (III) Mn (III) is prepared , Mn (III) Mn (IV) or Mn (IV) Mn (IV) and a transition metal ligand of the formula (I):

Where:

;
p is 3;
R is independently selected from hydrogen, C1-C6 alkyl, CH ₂ CH ₂ OH, CH ₂ COOH and pyridin-2-ylmethyl;
R1, R2, R3 and R4 are independently selected from H, C1-C4 alkyl, C1-C4 alkyl hydroxy. 2. The method according to claim 1, in which the manganese transition metal catalyst is present in a concentration of 0.0005-0.2 kg / ton of absolutely dry cellulose and hydrogen peroxide is present in a concentration of 0.1-25 kg / ton of absolutely dry cellulose. 3. The method of claim 1, wherein R is independently selected from hydrogen, CH ₃ , C ₂ H ₅ , CH ₂ CH ₂ OH and CH ₂ COOH. 4. The method of claim 2, wherein R is independently selected from hydrogen, CH ₃ , C ₂ H ₅ , CH ₂ CH ₂ OH and CH ₂ COOH. 5. The method of claim 1, wherein R, R1, R2, R3, and R4 are independently selected from H and Me. 6. The method of claim 2, wherein R, R1, R2, R3, and R4 are independently selected from H and Me. 7. The method of claim 3, wherein R, R1, R2, R3, and R4 are independently selected from H and Me. 8. The method of claim 4, wherein R, R1, R2, R3, and R4 are independently selected from H and Me. 9. The method of claim 1, wherein the catalyst is prepared from 1,4,7-trimethyl-1,4,7-triazacyclononane (Me ₃ -TACN). 10. The method according to p. 2, in which the catalyst is obtained from 1,4,7-trimethyl-1,4,7-triazacyclononane (Me ₃ -TACN). 11. The method according to PP. 1-10, in which the process of grinding the mass is carried out until reaching a value of Shopper Riegler (SR) 10-30 ° for the production of paper towels. 12. The method according to PP. 1-10, in which the process of grinding the mass is carried out until reaching the value of Shopper Riegler (SR) 15-50 ° for the production of printing and writing paper. 13. The method according to PP. 1-10, in which the mass grinding process is carried out until the Shopper Riegler (SR) value of 50-90 ° is reached for the production of tracing paper. 14. The method according to PP. 1-10, in which the process of grinding the mechanical mass is carried out until the Shopper Riegler (SR) value of 20-80 ° is reached. 15. The method according to PP. 1-10, in which the catalyst and hydrogen peroxide are added to the mass in a device selected from: a hydraulic diluent; mass pool with high mass density; mass washers; mass pool exposure; a mass pool for leveling mass concentration; mental pool; chopper; pulp liquefaction tank; and a mass pool for storing mass. 16. The method according to p. 15, in which the chopper is selected from: grinding machines; Dutch threshing drums; low angle cone shredders; shredders with an average angle; wide-angle choppers; single plate shredders; double disc grinders; multi-disc shredders. 17. The method according to PP. 1-10, in which the catalyst and hydrogen peroxide are added to the mass during one of the bleaching stages for processing chemical, mechanical or waste paper. 18. The method according to p. 17, in which the catalyst and hydrogen peroxide are added to the mass in a device selected from a mass mixer; bleaching tower, pipes to hold the mass; mass washers; mass storage battery; steam jet mixer; and grinding machine. 19. The method according to PP. 1-10, in which the stage of bleaching the cellulose fiber is preliminarily carried out. 20. The method according to PP. 1-10, in which the solution containing the catalyst and hydrogen peroxide includes 0.01-50 kg / ton of absolutely dry cellulose of an organic complexing agent, the complexing agent selected from aminophosphonate complexing agent and carboxylate complexing agent. 21. The method according to p. 20, in which the complexing agent is selected from: sodium salt of diethylene triamine penta (methylenephosphonic acid), MGDA (methylglycine diacetate), GLDA (glutamic acid diacetate), IDS (iminodisuccinate), EDDS (ethylene diamindisuccinate), EDTA DETA (diethylene triamine pentaacetate). 22. The method according to PP. 1-10, in which the energy consumption during grinding is controlled and based on the threshold of energy consumption when processing the mass into paper, fabric or cardboard. 23. The use of an aqueous solution of a manganese transition metal catalyst and hydrogen peroxide at pH 6-13, in which the manganese transition metal catalyst is preliminarily formed from mononuclear Mn (II), Mn (III), Mn (IV) or a dual core Mn (II) Mn ( II), Mn (II) Mn (III), Mn (III) Mn (III), Mn (III) Mn (IV) or Mn (IV) Mn (IV) and a ligand of the formula (I):

Where:

;
p is 3;
R is independently selected from hydrogen, C1-C6 alkyl, CH ₂ CH ₂ OH and CH ₂ COOH. and pyridin-2-ylmethyl;
R1, R2, R3, and R4 are independently selected from H, C1-C4 alkyl, and C1-C4 alkylhydroxy to increase the sagacity of the cellulose fibers during the milling process. 24. The use according to claim 23, in which the application includes a method according to PP. 1-10. 25. Paper, fabric or cardboard, which are obtained by the method according to paragraphs. 1-10 or the use of claim 23.