DE102009010696A1 - Method for the production of magazine paper from fiber material suspension, comprises grinding lignocellulosic, bleached, high strength fiber material from wood or annual plants - Google Patents

Abstract

The method for the production of magazine paper from fiber material suspension, comprises grinding lignocellulosic, bleached, high strength fiber material from wood or annual plants with a power of 250 kWh/t. The material suspension consists of de-inked wastepaper and a portion of 5-50% of lignocellulosic, bleached, high strength fiber material from wood or annual plants that have a breaking length of 7.5 km at 15[deg] SR and a lignin content of 13% related to the fiber material for soft wood, in unground condition. The method for the production of magazine paper from fiber material suspension, comprises grinding lignocellulosic, bleached, high strength fiber material from wood or annual plants with a power of 250 kWh/t. The material suspension consists of de-inked wastepaper and a portion of 5-50% of lignocellulosic, bleached, high strength fiber material from wood or annual plants that have a breaking length of 7.5 km at 15[deg] SR and a lignin content of 13% related to the fiber material for soft wood, in unground condition or a breaking length of greater than 5.0 km at 20[deg] SR and a lignin content of 10% related to the fiber material for hardwood, in bleached condition, or a breaking length of greater than 4.0 km at 20[deg] SR and a lignin content of 10% related to the fiber material for annual plants in bleached condition. Another fiber material is formed by stone groundwood pulp, thermomechanical pulp, bleached chemi-thermo-mechanical pulp, chemithermo mechanical pulp and/or alkaline peroxide mechanical pulp. The breaking length is greater than 10 km for softwood-fiber-mass at 15[deg] SR, is greater than 5.5 km for hardwood fiber mass at 20[deg] SR or is greater than 5.5 km for annual plant-fiber mass at 20[deg] SR. The portion of high strength fiber material is 10-25% and the portion of the another fiber material is less than 15%. The portion of the de-inked wastepaper on total fiber material is greater than 80%. The high strength fiber material is produced from eucalyptus or aspen tree. The softwood-fiber mass is ground with a power of 250 kWh/t. The high strength fiber material in the softwood-fiber mass is ground with a power of 280 kWh/t. The ground, high strength fiber material in the softwood-fiber mass has a breaking length of 8.6 km at a grinding degree of 16[deg] SR. The ground, high strength fiber material in the hardwood-fiber mass has a breaking length of 6.5 at a grinding degree of 30[deg] SR. The high strength fiber material is bleached up to 80% white.

Description

The The invention relates to a method for producing magazine paper from a fiber suspension comprising substance.

at Magazine papers are LWC papers, d. H. Painted Printing papers with a relatively low coating weight and SC papers, d. H. supercalendered papers.

such Fibrous webs are currently becoming major from stone-ground fibers (SGW), TMP-pulp or from one Mixture made of SGW and DIP (deinked waste paper).

For high quality varieties is the proportion of relatively cheap DIP at about 50%. A desirable for cost reasons Increasing the DIP share fails due to the high quality requirements on these magazine papers, especially with regard to the optical and the surface properties.

The The object of the invention is therefore the production of cost-effective Magazine paper to allow the requirements to the surface properties, optical properties and strength at the lowest possible freeness.

According to the invention was the object achieved in that the stock suspension at least DIP and a proportion between 5 and 50% of lignocellulosic, bleached, contains high-strength fibrous material from wood or annual plants, in the unmilled state a tear length of more than 7.5 km at 15 ° SR and a lignin content of at least 13% related to the otro pulp for softwood bleached Condition or a breaking length of more than 5.0 km at 20 ° SR and a lignin content of at least 10% on the otro pulp for hardwood in the bleached state or a tearing length of more than 4.0 km at 20 ° SR and a lignin content of at least 10% based on the otro pulp for annual plants in the bleached state.

These high-strength fibers already show at one compared to previously used fibers much lower freeness high strength values. The fibrous material according to the invention is already at low degree of grinding and thus less expenditure of grinding energy able to build a good bond to adjacent fibers, so that a relatively small proportion of the high-strength pulp the required tear strength even at a high level of DIP can guarantee.

By The bleaching treatment of the high-strength pulp improves the fiber properties, especially with regard to whiteness considerably. With the bleaching treatment but also increase the breaking lengths and thus the tear strength. The high-strength pulp is not only characterized by high tear lengths out. Rather, the strength level is high overall.

Of the Bleached, high-strength pulp improves because of its high bulk and the high whiteness the properties of one of the pulp suspension produced fibrous web such that a high, especially on 60% lying DIP content in the stock suspension for magazine papers is possible.

Of the Share of different pulp in the stock suspension refers here on their dry weight content of the entire pulp the suspension.

in the Interest of a high strength of the fibrous web can it from Be an advantage if the tear length for Softwood pulp at 15 ° SR greater than 9 km, preferably greater than 10 km, for Hardwood pulp at 20 ° SR larger as 5.5 and for annual plant pulp at 20 ° SR greater than 4.5 km, preferably larger than 5.0 km and in particular greater than 5.5 km is.

For Most magazine papers can be an optimal ratio between costs and web properties with a share of high-strength Achieve pulp between 10 and 25%.

In Dependence on the requirements of the fibrous web, but also the quality and the price of the available standing fibrous materials, it may be advantageous if in addition to DIP and the high-strength fiber other fibers in the stock suspension available.

there the other fibrous materials, in particular of SGW, TMP, APMP, BCTMP or CTMP pulps.

Around However, the cost advantage of using DIP in sufficient Way to be able to use and the properties of the fibrous web not significantly affect the proportion the other fibers less than 25%, preferably less than 15%, in particular less than 10%, and / or the proportion of the DIP at total pulp greater than 60%, preferably greater than 70% and in particular larger to be 80%.

Around can maximize the cost advantage of the DIP However, it would be beneficial if in addition to DIP and the high-strength pulp no other pulp is present in the pulp suspension.

In the interest of a high bulk and good optical properties of the high-strength pulp should this be made of fine hardwood, especially eucalyptus or quaking poplar.

to Optimization of tear strength, surface properties and the optical properties of the pulp suspension manufactured fibrous web should be the high-strength pulp with a Power of at least 100 kWh / t, preferably of at least 250 kWh / t, to be ground.

With The advantage should be the high-strength pulp in softwood fiber pulp with a capacity of at least 220 kWh / t, preferably of at least 280 kWh / t, to be ground.

in the The result was the milled, high-strength pulp in softwood fiber pulp a tearing length of at least 8.6 km at one Grinding degree of 16 ° SR and in hardwood pulp a breaking length of at least 6.5 at a freeness of 30 ° SR.

Of Further, the high-strength pulp should be warranted a sufficient whiteness of the fibrous web up to a Value of 72% ISO, preferably 75% and especially 80% white to be bleached.

following the invention should be closer to an embodiment be explained.

• – Herstellen einer Chemikalienlösung mit mehr als 5% Chemikalien (berechnet als NaOH) für Nadelholz oder mit mehr als 3,5% Chemikalien (berechnet als NaOH) für Laubholz oder mit mehr als 2,5% Chemikalien (berechnet als NaOH), jeweils bezogen auf die otro Menge des eingesetzten Holzes,
• – Mischen der Chemikalienlösung mit dem Holz bzw. Einjahrespflanzen in einem vorgegebenen Flottenverhältnis,
• – Erwärmen der Chemikalienlösung und des Holzes bzw. Einjahrespflanzen auf eine Temperatur über Raumtemperatur und anschließend entweder (1. Alternative)
• – Entfernen frei fließender Chemikalienlösung und
• – Aufschließen des Holzes bzw. Einjahrespflanzen in der Dampfphase oder (2. Alternative)
• – Aufschließen des Holzes bzw. Einjahrespflanzen in Gegenwart der Chemikalienlösung in flüssiger Phase und
• – Separieren der frei fließenden Chemikalienlösung und des Holzes bzw. der Einjahrespflanzen.

In the production of the lignocellulosic pulp-containing pulp suspension according to the invention, it is essential that at least one suspension component of wood or annual plants with a lignin content of at least 15% for softwood and 12% for hardwood and 10% for annual plants, in each case based on the otro pulp with the following Steps is made:

• - Make a chemical solution with more than 5% chemicals (calculated as NaOH) for softwood or with more than 3.5% chemicals (calculated as NaOH) for hardwood or with more than 2.5% chemicals (calculated as NaOH), each purchased on the otro amount of wood used,
• Mixing the chemical solution with the wood or annual plants in a predetermined liquor ratio,
• - Heating the chemical solution and the wood or annual plants to a temperature above room temperature and then either (1st alternative)
• - Remove free-flowing chemical solution and
• - digesting the wood or annual plants in the vapor phase or (2nd alternative)
• - Harvesting the wood or annual plants in the presence of the chemical solution in the liquid phase and
• - Separating the free-flowing chemical solution and the wood or annual plants.

The The inventive method is based on that for the production of high-yield fibers, higher quantities of chemicals be used as usual. More than 5% chemicals for Softwoods are well above the usual Chemical quantities for technical pulp production, also more than 3.5% hardwood and 2.5% chemicals for annual plants. This high use of chemicals provides Fibers with good yield and excellent strength properties. So are for softwood at grinding degrees of only 12 ° SR Tear lengths of more than 8 km up to 15 ° SR, but also tear lengths of more than 9 km and more measured as 10 km. For hardwoods are added only 20 ° SR values of more than 5 km, but also breaking lengths measured more than 6 km and more than 7 km. This will be the desired high strength level achieved.

It is an extraordinary advantage of the invention View method that these strength values already at extremely low degrees of grinding are achieved, as previously for High yield pulps were not available. Fibers after the state of the art show at grindings of 12 ° SR to 15 ° SR for softwood pulps or 20 ° SR for hardwood an unacceptable level of strength. Known Fibers have so far been fibers at these low degrees of grinding which did not show sufficient binding power and the corresponding insufficient strength properties for an economical use of such fibers have bid.

When Annual plants are particularly suitable for bamboo, hemp, rice straw, Bagasse, wheat, miscanthus or similar

By contrast, the fibrous materials produced by the process of the invention have tear lengths of more than 8 km up to 11 km and tear strengths of more than 70 cN up to more than 110 cN, even at grinding degrees in the range of 12 ° SR to 15 ° SR, based on a Leaf weight of 100 g / m ² . These low freeness levels are also achieved with a low specific demand for grinding energy, which is less than 500 kWh / t pulp for softwood pulps, and for hardwood pulp the demand for grinding energy may even be less than 300 kWh / t pulp. The realization that the high level of strength is achieved even at low grinding degrees of 12 ° SR to 15 ° SR for softwood and 20 ° SR for hardwood and below, is an integral part of the invention.

These high strength values in combination with low grinding degrees are suitable for fibrous materials a lignin content of more than 15% for softwood pulps, more than 12% for hardwood pulps or more than 10% for annual plants not yet known. However, the high strength level can also be maintained for fibers with an even higher lignin content. The inventive method is also suitable for the production of softwood pulps with a lignin content of more than 18%, preferably more than 21%, advantageously more than 24% based on the otro fiber mass. Hardwood fibers with a lignin content of more than 14%, preferably more than 16%, more preferably more than 18% and annual plants with a lignin content of more than 10%, preferably more than 12%, in particular more than 19% can also with the lignin are prepared according to the invention and show a high level of strength.

The Composition of the chemical solution used for digestion Can in coordination with the aufzuschließende wood or the Annual plants and the desired pulp properties be determined. As a rule, only a sulphite component is used used. Alternatively or in addition, a sulfide component come on. A digestion with a sulfite component is through the presence of sulfide components is not disturbed. Technically is usually used sodium sulfite, but also the use of Ammonium or potassium sulfite or magnesium bisulfite is possible. In particular, when high amounts of sulfite can be used to dispense with the use of an alkaline component, because even without the addition of alkaline components, a high pH adjusts the digestion.

to PH adjustment and delignification support For example, an acidic and / or an alkaline component can be added. The alkaline component is usually sodium hydroxide (NaOH) used. But it is also possible to use carbonates, especially sodium carbonate. All information on chemical quantities the digestion process in this document, e.g. B. for the total use of chemicals or for the distribution of the sulfite component and the alkaline component, are calculated and indicated, unless otherwise stated as sodium hydroxide (NaOH).

As an acidic component, acids can be added in order to set the desired pH. However, preference is given to the addition of SO ₂ , if appropriate in aqueous solution. It is inexpensive and readily available, especially if the spent chemical solution z. B. based on sodium sulfite, after digestion is prepared for further use.

It is considered as an independent inventive achievement, the benefits of using a quinone component for the high yield digestion according to the invention to have recognized. Quinone components, especially anthraquinone, So far, in the production of pulps with minimal Lignin content used to end of the digestion an undesirable To prevent attack on the carbohydrates. By adding quinone components it becomes possible to continue the digestion of wood until the Continue nearly complete degradation of lignin. It has proven to be an unprecedented, unexpected property of quinone components proved that these are the speed of lignin degradation significantly increase in the production of high yield pulps. The duration of the digestion can z. B. in the production of softwood pulps by more than half, depending on the digestion conditions more than three quarters are shortened. This remarkable Effect is achieved with minimal use of quinone. Optimal is an employment of z. As anthraquinone, the between 0.005% and 0.5%. Use of anthraquinone of up to 1% also provides the desired effect. A use of more than 3% anthraquinone is mostly uneconomic.

Out one or more of the aforementioned chemicals, a chemical solution is prepared. Mostly an aqueous solution is used. As option can also be the use or addition of organic solvents be provided. Alcohol, especially methanol and ethanol especially effective chemical solutions when mixed with water for the production of high quality high yield pulps. The mixing ratio of water and alcohol can be for the respective raw material can be optimized in few attempts.

The for producing a pulp with a yield of at least 70% amount of chemicals to be used according to the invention is at least 5% for softwood, at least 3.5% for hardwood and at least 2.5% for annual plants, in each case based on the otro wooden or Annuals mass. The quality of the produced Pulp shows the best results in a chemical application from up to 15% for softwood to 10% for hardwood and up to 10% in annual plants. Preference is given between 9% and 11% chemicals related to the used otro wood Softwood, added. For hardwood is the Use of chemicals rather lower, preferably between 4% and 10%, more preferably between 6% and 9%, and annual plants between 3 and 10%.

As already explained above, the setting of a specific pH is by no means the case conducive. Only if z. B. special properties of the pulps (especially high whiteness, a certain ratio of breaking lengths and tear resistance) to be achieved with the digestion, it may be useful to add acid or an alkaline component before or during the digestion. According to an advantageous embodiment of the method according to the invention, regardless of the chosen use of chemicals as a whole, a ratio between an alkaline component and sulfur dioxide (SO ₂ ) can be adjusted within a wide range. SO ₂ is mentioned here as representative of the above-mentioned acidic component. So it can be used instead of SO ₂ and an acid. Since the possibly added quinone component is used only in minimal amounts, usually well below 1%, it is negligible for setting this ratio. A ratio of alkaline component: SO ₂ in a range of 5: 1 to 1.6: 1 is well suited to carry out the method according to the invention and to achieve fibers with high strength properties. A common, particularly suitable range is between 2: 1 and 1.6: 1. The adjustment of the proportionate components is dependent on the aufzuschließenden raw material and the respective selected process control (digestion temperature, digestion time, impregnation).

The inventive method can in a wide pH range can be performed. The relationship from alkaline component to acidic component or use an acidic or an alkaline component can be adjusted that at the beginning of the process, a pH between 6 and 11, preferably between 7 and 11, more preferably between 7.5 and 10 is set. The more alkaline pH's between 8 and 11, which for the method according to the invention is advantageous, also favor the effect of the quinone component. The inventive method is in terms of pH tolerant; There are few chemicals for pH adjustment required. This has a favorable effect on the cost of Chemicals off.

Without further addition of acid or alkaline component yourself, z. B. for softwood, at the end of the digestion pH between 5 and 9, usually between 6.5 and 9 in the free-flowing chemical solution and the dissolved therein organic components, the were liquefied by the digestion. To the solved ones Organic ingredients include mainly lignosulfonates.

The Fleet ratio, so the ratio of the amount of otro wood or annual plants to the chemical solution, is set between 1: 1.5 and 1: 6. A liquor ratio is preferred from 1: 2 to 1: 4. In this area is a good and easy mix and impregnation of the material to be digested guaranteed. For softwood is a liquor ratio of 1: 3.5 is preferred. For wood chips with large Surface, the fleet ratio can also be clear higher, fast wetting and impregnation to enable. At the same time, the concentration of Chemical solution should be kept high enough to be circulated Liquid quantities do not become too big.

The Mixture or impregnation of wood or year-old pulp is preferably at elevated temperatures. A heating the wood chips and the chemical solution up to 110 ° C, preferably up to 120 ° C, more preferably up to to 130 ° C leads to a fast and even Digestion of the wood. For mixing or impregnating the wood chips is a period of up to 30 minutes, preferably up to 60 minutes, more preferably up to 90 minutes advantageous. The optimal period of time depends on other of the amount of chemicals, the liquor ratio, the selected temperature and the type of digestion (liquid or vapor phase).

Of the Digestion of mixed with the chemical solution or impregnated lignocellulosic material is preferably carried out at temperatures between 120 ° C and 190 ° C, preferably between 140 ° C and 180 ° C. For the most Woods are digestion temperatures between 150 ° C and 170 ° C set. Higher or lower Temperatures can be adjusted, but in this temperature range stand the energy expenditure for the heating up and the acceleration the digestion in an economic relationship to each other. Higher temperatures can also be negative affect the strength and whiteness of the pulp. The pressure generated by the high temperatures can by appropriate Design of the stove can be caught easily. Usually The duration of the heating is only a few minutes, usually up to 30 minutes, advantageously up to 10 minutes, in particular, when heated by steam. The duration of the heating up can up to 120 minutes, preferably up to 60 minutes, z. For example is digested in the liquid phase and the chemical solution to heat together with the chips.

The duration of the digestion is chosen especially depending on the desired pulp properties. The duration of the digestion can be shortened to up to 2 minutes, z. B. in the case of a vapor phase digestion of a hardwood with low lignin content. But it can also be up to 180 minutes, if z. B. the digestion temperature low and the natural lig nine content of the wood to be split is high. Even if the initial pH of the digestion is in the neutral range, a long digestion time may be required. Preferably, the digestion time is up to 90 minutes, especially in coniferous wood. Particularly preferably, the digestion time is up to 60 minutes, advantageously up to 30 minutes. A digestion time of up to 60 minutes is mainly considered for hardwoods.

at Annual plants, the digestion time is up to 90 minutes. The use of a quinone component, in particular anthraquinone, allows a reduction of the digestion time up to to 25% of the time required without the addition of anthraquinone. Will on the Use of quinone components dispensed with, lengthens for comparable digestion results, the digestion time for more than an hour, for example from 45 minutes to 180 minutes.

To an advantageous embodiment of the invention Procedure is the duration of digestion depending on set by the selected fleet ratio. The lower the fleet ratio, the shorter the process duration can be set.

The Production of high yield pulp with high chemical use from more than 5% for softwood, from more than 3.5% for Hardwood and at least 2.5% for annual plants appears initially uneconomical. But experiments have shown that only a part of the chemicals during the partial Digestion of the lignocellulosic material is consumed. The vast majority of chemicals are left unused discharged, either before digestion (vapor phase digestion) or after digestion (digestion in the liquid phase). The actual consumption of chemicals is below that in the Digestion solution amounts used.

Of the Chemical consumption is recorded as the amount of chemicals - related to the originally used amount of chemicals - after removing or separating the chemical solution as well if necessary, detecting chemical solution after defibering or in conjunction with a detection of the chemical solution is measured. The consumption of chemicals depends on the absolute amount of used for the digestion Chemicals, based on the otro wood mass to be broken up. The higher the use of digestion chemicals is to the lower is the direct sales of chemicals. At a mission of 27.5% chemicals based on otro wood pulp, for example only about 30% of the chemicals used consumed. When used However, 15% of chemicals related to otro wood will account for 60% of consumed chemicals, as demonstrated in laboratory experiments could be. The consumption of chemicals for the process according to the invention is according to a preferred embodiment of Process during digestion up to 80%, preferably up to 60%, more preferably up to 40%, advantageously up to 20%, particularly advantageous up to 10% of the use of chemicals at the beginning the digestion is used.

Of the Chemical consumption for producing a ton of pulp lies at about 6% to 14% sulphite and / or sulphide component and, if applicable, alkaline and / or acidic component and optionally quinone component based on otro pulp (deciduous and coniferous or annual plants). According to the invention, this amount of chemicals, to produce a pulp with the given properties. However, a uniform process result to ensure and possibly special, desired To get pulp properties, it may be useful prove higher levels of chemicals for digestion to use, for. As the above mentioned up to 30% chemicals based on otro wood or annual plant mass.

Of the Use of these chemicals at the beginning of the digestion shows advantageous effect, since the fibers obtained in this way previously unavailable properties, in particular high strength properties and have high degrees of whiteness. In particular, so far no Digestion methods available that have a broad pH spectrum from neutral to alkaline fiber with high Strengths generated. As economically attractive it turned out that the inventively produced Fibers with much lower energy consumption to specified Grinding degrees to grind are known as fibrous materials. In addition, develop the high strengths already at unusually low degrees of grinding from 12 ° SR to 15 ° SR for softwood and from 20 ° SR for hardwood.

Excess chemicals are present after mixing and impregnating the wood with the chemical solution or after digestion in the free flowing liquid. This excess is deducted before digestion (1st alternative) or after digestion (2nd alternative). According to an advantageous embodiment of the method, the composition of the removed chemical solution is detected and then adjusted to a predetermined composition for re-use for the production of fibers. The chemical solution that is removed before or after the decomposition of the wood or annual plants no longer has the original composition. At least part of the chemicals used for digestion is - as before standing described - penetrated into the aufzuschließende material and / or has been consumed in the digestion. The unused chemicals can easily be used again for the next digestion. However, it is proposed according to the invention to first determine the composition of the removed chemical solution and then the consumed proportions of z. As sulfite, alkaline component, quinone component or water or alcohol to supplement to restore the predetermined composition for the next digestion. This supplementary step is also called strengthening.

It is to be regarded as a significant advantage of this measure, that the chemical solution even more so when removing before digestion, but also when removed after digestion contains no or very few substances that are when reusing the starched chemical solution for the next digestion as disturbing prove. The inventive method that it turns off, in the impregnation an oversupply can provide digestion chemicals So despite the initially uneconomical appearing Procedure of high chemical use extremely work economically, because the removal or separation and Strengthening the chemical solution can be easy and be carried out inexpensively.

The inventive method is specifically controlled so that only as little as possible of the starting material used degraded or dissolved. The aim is to have a pulp to produce a lignin content of at least 15% based on the otro fiber mass, preferably a lignin content of at least 18%, more preferably 21%, advantageously at least 24%. For hardwood is sought a lignin content of at least 12% based on the otro fiber mass to reach, preferably of at least 14%, more preferably at least 16%, preferably at least 18%. In annual plants the preferred lignin content is between 10 and 28%, in particular between 12 and 26%.

The Yield of the method lies at least 70%, preferably more than 75%, advantageously at more than 80%, in each case based on the wood used. This yield correlates with the above lignin content of the pulp. The original one Lignin content of wood is specific to the species. The yield loss arises predominantly in the present process as a loss of lignin. In non-specific digestion the proportion of carbohydrates is significantly increased, for. B. because digestion chemicals are undesirable in themselves also bring cellulose or hemicelluloses into solution.

A Another advantageous measure is, after defibering and optionally grinding the lignocellulosic material remaining one Chemical solution to remove and re-use. In a preferred embodiment, this reuse can have two aspects include. On the one hand, this is degraded during the partial digestion or dissolved organic material, predominantly Lignin, further used. For example, it is burned by process energy to win. Or it is prepared to be used elsewhere. Second, the used and unused chemicals again prepared so that they for a renewed, partial digestion can be used by lignocellulosic material. This includes the treatment of used chemicals.

To a particularly preferred variant of the invention Procedure, the chemical solution used is extraordinary used efficiently. After pulping and possibly grinding, the pulp becomes Washed to the chemical solution as much as possible to displace by water. That in this washing or Displacement process resulting filtrate contains considerable amounts of chemical solution and organic material. According to the invention this Filtrate of the removed or separated chemical solution fed before the chemical solution strengthened and the next digestion is supplied. The in the filtrate contained chemicals and organic components do not disturb the digestion. As far as they still have a contribution for delignification during the next digestion their salary is recorded in the chemical solution and in determining the required for this digestion Chemical quantity considered. The further in the filtrate contained chemicals behave during the upcoming Digestion inert. They do not bother. The ones contained in the filtrate Organic components are also inert. you will be after the next digestion during the treatment of the chemical solution used further, either to generate process energy or on other way.

It is considered to be particularly advantageous that through this leadership Filtrate less fresh water and less chemicals for the digestion can be used. At the same time, it becomes a maximum detected dissolved organic material. Also this improved Use of the dissolved organic material improves the economy of the invention Process.

With regard to the bleaching of the high-strength pulp, in particular the FAS bleach is on the DE 10 2007 007 654 directed.

As a result, the high-strength pulp should have a whiteness of at least 75%.

Out a mixture of 10-20% of this high-strength pulp and 80-90% DIP based on the total dry weight Pulp can be mixed with water a pulp suspension prepare for the production of fibrous webs, in particular Magazine paper is very suitable.

The Disadvantages of DIP in terms of whiteness and tear resistance are compensated by the high-strength pulp, so that a high DIP share is possible. The result is significant cost savings.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - DE 102007007654 [0055]

Claims (17)

A process for the production of magazine paper from a fiber suspension comprising material, characterized in that the pulp suspension contains at least DIP and a proportion of between 5 and 50% of lignocellulosic, bleached, high-strength pulp of wood or annual plants, which in the unground state has a tearing length of more than 7 , 5 km at 15 ° SR and a lignin content of at least 13% in relation to the otro pulp for softwood in the bleached state or a breaking length of more than 5.0 km at 20 ° SR and a lignin content of at least 10% relative to the otro pulp for hardwood in bleached condition or having a tearing length of more than 4,0 km at 20 ° SR and a lignin content of at least 10% relative to the otro pulp for annual plants in the bleached state. Method according to claim 1, characterized in that that the breaking length for softwood fiber pulp at 15 ° SR greater than 9 km, preferably is greater than 10 km. Method according to claim 1 or 2, characterized that the breaking length for hardwood fiber pulp at 20 ° SR is greater than 5.5 km. Method according to one of the preceding claims, characterized in that the tear length for Annual plant pulp at 20 ° SR larger than 4.5 km, preferably greater than 5.0 km and especially greater than 5.5 km. Method according to one of the preceding claims, characterized in that the proportion of high-strength pulp between 10 and 25%. Method according to one of the preceding claims, characterized in that in addition to DIP and the high-strength pulp still other fibers are present in the stock suspension. Method according to Claim 6, characterized that the other fibers of SGW, TMP, BCTMP, CTMP, APMP pulps be formed. Method according to claim 6 or 7, characterized the proportion of other fibers is less than 25%, preferably is less than 15%. Method according to one of claims 6 to 8, characterized in that the proportion of DIP in the entire pulp greater than 60%, preferably larger than 70% and especially greater than 80%. Method according to one of claims 1 to 5, characterized in that in addition to DIP and the high-strength fiber no other pulp is present in the pulp suspension. Method according to one of the preceding claims, characterized in that the high-strength pulp of fine Hardwood, especially eucalyptus or aspen is produced. Method according to one of the preceding claims, characterized in that the high-strength fiber is ground. Method according to one of the preceding claims, characterized in that the high strength pulp with a Power of at least 100 kWh / t, preferably from above 250 kWh / t, is ground. Method according to one of claims 11 to 13, characterized in that the high-strength pulp in softwood fiber mass with a capacity of at least 220 kWh / t, preferably at least 280 kWh / t, is ground. Method according to one of claims 11 to 14, characterized in that the ground, high-strength pulp with softwood fiber mass a tear length of at least 8.6 km at a freeness of 16 ° SR has. Method according to one of claims 11 to 14, characterized in that the ground, high-strength pulp with hardwood pulp a tear length of at least 6.5 at a freeness of 30 ° SR has. Method according to one of the preceding claims, characterized in that the high-strength pulp to a Value of 72% ISO, preferably bleached by 80% whiteness becomes.