WO2019219299A1

WO2019219299A1 - Method and device for producing a fibrous web

Info

Publication number: WO2019219299A1
Application number: PCT/EP2019/059007
Authority: WO
Inventors: Linus FRIEDRICH; Wolfgang Mannes; Benjamin Méndez-Gallon
Original assignee: Voith Patent Gmbh
Priority date: 2018-05-18
Filing date: 2019-04-10
Publication date: 2019-11-21

Abstract

The invention relates to a method for producing a surface-treated fibrous web (33), in particular a web of cardboard or packaging paper, at least comprising a material preparation stage (4), at least one headbox (24), a forming section (25) and a dry end (27) for a paper machine for forming the fibrous web (33), wherein a fiber-containing raw material (2), which at least partially contains waste paper with fillers and fines, in particular OCC, and/or paper waste (3) accumulated in the method for producing a fibrous web (33) is supplied to a dissolving device (11) of the material preparation stage (4), and at least one suspension flow (12) is formed in the dissolving device. The suspension flow is supplied to a washing stage (13) in order to separate the fillers and fines, thereby forming a filler/fine flow (14) and a fibrous material suspension flow (15). The fibrous material suspension flow (15), which has little filler and fine, is supplied to at least one headbox (24), and the filler/fine flow (14) is separated into a filler flow (18) and a fine flow (19) in a separating stage (17), said filler flow (18) being applied at least on one side onto the fibrous web (33) for the surface treatment of the fibrous web (33). The invention also relates to a device for carrying out the method.

Description

Method and device for producing a fibrous web

The invention relates to a method and a device for producing a surface-treated fibrous web, in particular a cardboard or packaging paper web.

These fibrous webs can be single-layered, multi-layered, multilayered or in a combination thereof. Thus, document W012041392 A1 describes the production of an at least three-ply fibrous web in a forming section of a paper machine. The Formierpartie comprises a plurality Langsiebeineinheiten each for forming a single layer of the fibrous web. These individual layers are zusammengegautscht to produce the multilayer fibrous web. The raw materials for the middle layer are usually cardboard waste (OCC, old corrugated container pulp), mixed waste paper, newspapers, paper scrap and others. For the supine position, deinked fabric, pulp, CTMP and also OCC and paper scrap are used.

Due to the increasing use of used paper and the increasing recycling rate, the proportion of fillers and fines in the raw materials from the recycling of fiber-containing products is increasing more and more. This leads to loss of strength in the papers produced, especially in cardboard and packaging papers. This disadvantage is offset by higher basis weights or by increased use of higher quality raw materials, such as pulps. This leads to higher production costs, in particular in the production of cardboard and packaging papers.

The object of the invention is therefore to propose a method and a device for producing surface-treated fibrous webs, in particular cardboard or packaging paper webs, with which it is possible on the one hand to reduce the manufacturing costs and on the other hand to maintain or increase the strength potential of the fibrous web. The object is solved by features of claim 1. The invention relates to a process for producing a surface-treated fibrous web, in particular a cardboard or packaging paper web, comprising at least a stock preparation, at least one headbox, a forming section and a dryer section for a paper machine for forming the fibrous web, wherein at least partially recycled paper with fillers and fines , in particular OCC, containing fiber-containing raw material and / or incurred in the process for producing a fibrous web paper pulp of a dissolver of the stock preparation and there at least one suspension stream (12) is formed and this a washing step for the separation of fillers and fines to form a filler Fine material stream and a pulp suspension stream is supplied and wherein the filler and feinstoffarme pulp suspension stream is fed to the at least one headbox and the filler Feinstof fstrom is separated in a separation stage in a filler stream and a fines flow and the filler stream is applied to the surface treatment of the fibrous web at least on one side of the fibrous web.

Further embodiments of the invention are set forth in the following description, in the subclaims and in the description of the figures.

The fillers contained in waste paper-based raw materials reduce the potential of the mechanical properties, in particular the strength potential, such as the breaking length, of the fibrous webs produced.

The fillers are mineral substances, such as kaolin, titanium dioxide, calcium carbonate. The fines, on the other hand, comprise organic substances which have been formed, for example, from organic fiber material. To determine the mass fractions of fillers and fillers of a fiber suspension, a sample of the pulp suspension is fractionated in a Bauer McNett fractionator (standard: TAPPI T 233) and the D100 fraction (sieve set ASTM 100) is used for the determination. The determination of the mass of fillers in the D100 fraction can be determined by treating the DlO fraction in an annealing furnace and determining the mass of the so-called refractory residue according to DIN ISO 1762. The mass of the incineration residue, based on the total mass of the solids in the sample of the pulp suspension, gives the filler mass fraction in the pulp suspension. The fines fraction results from the difference between the total mass of the solids in the D100 fraction and the mass of the firing residue of the D100 fraction, based on the total mass of the solids in the sample of pulp suspension.

The method can be applied not only to the filler-containing raw material used, but also to the reuse of filler-containing paper broke from the dyeing process. Paper broke can occur, for example, during a paper tear in the paper machine during production or by the edge trim of the fibrous web. Since the filler separated by the process according to the invention is fed to the multilayer fibrous web, this paper broke inevitably also contains fillers and fines and can thus be reused in an advantageous manner.

By separating the fillers from the suspension stream, the filler content in the fibrous web produced at least partially from the remaining pulp suspension stream is reduced, which increases its strength. In practice, therefore, the negative consequences of increasing Füllstoffgehalte in waste paper or the recirculated paper broke can be compensated. Depending on how much filler is separated from the fibrous raw material, it is also possible higher Strengths than with today's usual methods to achieve. This, in turn, also makes it possible to reduce the use of high-grade fibrous materials or to reduce the basis weight of the fibrous web or, in the case of a multilayer fibrous web, to reduce the individual layers of the multilayer fibrous web. This significantly reduces the cost per tonne of paper. On the other hand, the method also makes it possible to produce one-layer or multi-layer and / or multi-layer fibrous webs for a more demanding use in terms of mechanical stress, without reducing the weight per unit area. Another advantage is that the separated filler does not have to be disposed of expensively, but can be used for the production of the fibrous web, without adversely affecting the quality of the multilayer fibrous web. This is achieved in that the filler separated off in the separation stage is applied in a suitable manner for surface treatment to at least one side of the fibrous web formed.

The fibrous web can basically be produced in various ways. It can be single-layered and single-layered, single-layered and multi-layered, multi-layered or multi-layered and multi-layered. On the one hand, a single layer can be produced in a multi-layered manner, for example, by a multi-layer headbox, which delivers several layers, each with differently composed pulp suspensions, to the former and these are dewatered together there. On the other hand, multi-layer fibrous webs can be made of several, zusammengegummten individual layers, wherein the individual layers were dewatered on different formers. It is also possible to produce a multilayer fibrous web from one or more individual layers with one or more multilayer individual layers.

In a practical case, the filler stream is applied to one side of the fibrous web, for example on the top or the bottom. It is also possible to apply the filler flow on both sides of the fibrous web, ie on the upper side and the lower side.

In particular, the paper broke obtained in the production of pigment-coated fibrous webs, in particular in the case of multilayer fibrous webs, can be worked up particularly advantageously by the method according to the invention. In this case, the fillers introduced by the pigment-containing coating are largely separated from the fibrous part of the paper broke after dissolution in the washing stage.

In an advantageous embodiment, the paper broke and the fiber-containing raw material can be dissolved in a common dissolving device.

It is also conceivable to dissolve the paper broke in a separate dissolving device.

Furthermore, it is possible that a common washing stage and / or a common separation stage are used for the preparation of the paper broke and the fibrous raw material.

In one possible embodiment, a separate washing stage and / or a separate separating stage are used in each case for the preparation of the paper broke and the fibrous raw material.

Furthermore, the paper broke can also be processed in a separate stock preparation by the novel process. This separate stock preparation can also be part of the constant part of stock preparation.

Preferably, the separation in the washing step is carried out so that in the filler-fine material stream the filler mass fraction is equal to or more than 45%, preferably 50% to 70% and the fines mass fraction is less than or equal to 55%, in particular 30% to 50%. The filler mass fraction is calculated from the filler mass based on the total solids mass in the filler-fine material stream. This applies accordingly to the fine mass fraction.

In a practical case, the separation in the separation stage is carried out such that the filler mass fraction contains more than 50%, preferably more than 60%, more preferably more than 70%, in particular more than 80%, and less than 50% of the filler mass fraction in the filler stream. is.

The fines stream can again be fed to the dissolver or pulp suspension stream. A feed into the pulp suspending stream has the advantage, in particular at higher amounts of fines, that this counteracts the accumulation of fines in the dissolving device, thus avoiding an operational disturbance. A feed into the dissolution apparatus can be a cost-effective solution for small amounts of fines.

In some cases, it is advantageous if the filler stream is thickened. The thickening can be carried out by using a centrifugal field, in particular in a centrifuge. Here achieved fabric densities of over 50% are advantageous. It is also conceivable to carry out the thickening in a filtration process.

In an advantageous embodiment, the filler stream for jobs on the fibrous web of a coating application device, in particular a curtain applicator or a Sprühauftragswerk or a film applicator or a blade applicator supplied.

In one possible development, the filler stream is fed to a coating application device to form a precoat. the Pre-coat follows another coat applicator to apply a top coat. As a result, on the one hand, the line quality of the applied line is improved and, on the other hand, optical disadvantages of the fillers of the filler stream are compensated by the subsequent top line.

The precoat is preferably done with a curtain applicator or a spray applicator. Such so-called 1: 1 application processes have the advantage that the filler flow fed in this process is applied to the fibrous web 100% and not a part of it has to be recirculated.

The precoat can also be applied with a film applicator.

The subsequent top coat is carried out, for example, with a blade applicator or again with a commissioned work according to the 1: 1 application method.

Furthermore, it is also possible if the filler stream for jobs on the fibrous web of a glue application device, in particular a film applicator or a size press is supplied.

In one possible practical case, the filler stream is fed directly to an applicator.

In an advantageous development of the filler stream is mixed prior to the orders by an applicator on the fibrous web with at least one further stream to form a coating medium. The mixing can be carried out in a mixing device or in a treatment plant. The processing plant can be formed for example by the coating kitchen for the preparation of a coating color or a glue application medium. The filler stream is part of the Application medium. As a result, the possible negative influences of the fillers of the filler stream on the quality of the surface-treated fibrous web can be counteracted.

The at least one further material stream may comprise a starch solution or a starch solution with pigments. As a result, a pigmentation of the fibrous web can be achieved.

It is also conceivable if the at least one further material stream comprises one or more components from the following group: synthetic binders, such as, for example, styrene-butadiene-latex or acrylic latex; natural binders such as starch, casein; white pigments, which may be mineral or organic; Aid for adjusting the physical properties of the application medium.

The application medium can be used to apply a color stroke.

For example, the application medium containing white pigments can be used to produce a coating application for white-coated board and packaging papers, in particular WTTL (White Top Test Liners).

If the additional stream contains auxiliaries for adjusting the physical properties of the application medium, the following properties of the application medium can be influenced in order to achieve a good coating or glue application: color properties, low and high shear viscosity, water retention, pH, surface tension, stretchability, Lubricity and others.

The application medium can also be used to order a glue application. In a possible practical embodiment, the filler stream can be applied after the drying process in the dryer section and / or within the drying process of the dryer section. In the first case, an application device for applying the filler stream or the application medium is provided on the fibrous web after the dryer section. In the second case, the application device is arranged inside the dryer section. It is also possible if the dryer section includes a pre-dryer section and a post-dryer section. In this case, the application device is arranged between the pre-drying section and the after-dryer section.

However, it is also conceivable if the filler stream or the application medium is at least partially applied to the fibrous web in an offline coating machine.

In a possible further development, in addition to the raw material and / or the paper broke, pulp is added to the dissolving device.

The object is also achieved by a device for carrying out the method according to claim 1 for Fierstellung a surface-treated fibrous web, in particular a cardboard or packaging paper web. The apparatus comprises at least one stock preparation, at least one head box, a forming section and a dryer section for a paper machine for forming the fibrous web. In addition, it comprises a dissolving device in the stock preparation for feeding at least partially waste paper with fillers and fines, in particular OCC, containing fiber-containing raw material and / or incurred in the Fierstellung a coated fibrous web paper broke, and to form at least one suspension stream, a washing step for the separation of Fillers and fines from the suspension stream to form a filler-fine material stream and a filler and feinstoffarmmen pulp suspension stream, wherein the Pulp suspension stream is guided in a conduit which is connected to the at least one headbox, a separation stage for separating the filler-fine material flow in a filler stream and a fine material flow and an applicator for at least one-sided orders of the filler flow to the fibrous web.

The application device can be designed as a coating application device and / or a glue application device.

The invention expressly extends to such embodiments, which are not given by combinations of features of explicit back references of the claims, whereby the disclosed features of the invention - as far as is technically feasible - can be combined with each other.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings.

Show it

Figure 1 shows an exemplary embodiment of a device and a

Stock preparation for carrying out the process according to the invention in a schematic representation;

Figure 2 shows an exemplary embodiment of a paper machine for carrying out the method according to the invention in a simplified representation;

1 shows an exemplary embodiment of a stock preparation for carrying out the method according to the invention for the production of cardboard and packaging papers in a schematic representation. The fiber-containing raw material 2, which contains at least partially filler-containing OCC (old corrugated container) is a dissolving device 1 1, for example, a pulper fed. Of the After the dissolution and separation of impurities resulting suspension stream 12 is fed to a treatment stage 5. This may comprise a plurality of purification stages known per se, such as, for example, a high-consistency cleaning stage, a HW cleaning stage (heavy-particle cleaning stage), or a slot sorting stage. Subsequently, the suspension stream 12 is fed to a washing stage 13 for the separation of the fillers and fines to form a filler-fine material stream 14 and a pulp suspension stream 15. The separation in the washing step is carried out such that in the filler fines stream 14 the filler mass fraction is equal to or more than 45%, preferably 50% to 70% and the fines mass fraction is less than or equal to 55%, in particular 30% to 50%. The washing stage 13 may be carried out by known scrubbers with the product name Variosplit or CompactWasher. The pulp suspension stream 15 is conducted to a further treatment stage 6 in which it is thickened and dehydrated and optionally dispersed and re-diluted and ground in a grinding stage 9. Subsequently, the pulp suspension stream 15 is preferably fed via a conventional constant part 8 to the at least one headbox 24 of the forming section 25 to form a fibrous web 33, which in this case is a single layer.

The resulting in the washing stage 13 filler fines stream 14 is separated in a separation stage 17 in a filler stream 18 and a fines stream 19. The separation in the separation stage 17 is carried out such that in the filler stream 18 the filler mass fraction is more than 70%, preferably more than 85% and in the fine material stream 19 the filler mass fraction is less than 50%. The fines stream 19 is then fed to the pulp suspension stream 15 preferably after the washing stage 13. In particular, with low filler contents of the raw material 2, the fine material flow 19 can also be guided back into the opening device 11. However, it is also possible to direct part of the fines flow 19 into the dissolving device 11 and the remaining part into the pulp suspension flow 15. The filler stream 18 is in a Centrifuge thickener 7 thickened and supplied as a coating medium directly to an applicator 23 of a paper machine for applying the filler flow 18 on at least one side of the fibrous web 33. Optionally, after thickening, the filler stream 18 may initially also be supplied to a mixing device 20 or a preparation plant before it is fed to an application device 23 of a paper machine for application of the application medium 22 containing the filler stream 18 to at least one side of the fibrous web 33. In this case, a further material flow 21 is added to the filler flow and a coating medium 22 is formed in the mixing device 20 or the treatment plant 20. The further stream 21 may be a starch solution, synthetic binders such as styrene-butadiene latex or acrylic latex; natural binders such as starch, casein; white pigments; Auxiliaries for adjusting the physical properties of the application medium include.

The stock preparation 4 described here for the use of fibrous raw material 2, which contains at least partially filler-containing OCC (old corrugated container), also applies to the case where the raw material 2 filler-containing paper broke 3 from the production of the surface-treated fibrous web 33 in the dissolving device 1 1 added becomes. The filler content in the paper broke 3 can be considerable, in particular in a coating of the fibrous web 33 in the production process with a pigment-containing coating color, as is the case for example with white-covered liners. It may therefore also be advantageous to provide a separate stock preparation for carrying out the method according to the invention for the processing of paper broke 3. The separate stock preparation can also be part of the constant part 8 of the stock preparation 4.

2 shows an exemplary embodiment of a paper machine for carrying out the method according to the invention in a simplified representation. It is a paper machine for producing a surface-treated cardboard or packaging paper web. The fiber suspension stream 15 is fed to the headbox 24 following the constant part 8 of the stock preparation 4. This can be designed as a single-layer or multi-layer headbox. In the case of a multi-layer headbox, one or more fiber suspensions of different composition are additionally fed, which are then dewatered in the forming section 25 and form a multi-layered and single-layer fibrous web 33. In this case, the fiber suspension stream 15 is fed to at least one layer. The invention can also be applied to the Fierstellung multi-layer fibrous webs 33. In this case, the forming section 25 comprises a plurality of headboxes and a plurality of dewatering screens on which the various layers of the fibrous web are formed. The individual layers are combined to form the fibrous web 33. The fiber suspension stream 15 is fed to at least one headbox. Following the forming section 25, the fibrous web 33 is further mechanically dehydrated in a press section 26 before it is thermally dried in the dryer section 27. In the present case, the drying section 27 comprises a pre-drying section 28 and a post-dryer section 29. Between pre-drying section 28 and after-drying section 29, an application device 23, which is designed as a film applicator 30, arranged for applying glue. The glue may comprise a starch solution both with and without pigments. The filler stream 18 can be added directly to the glue application device 30 or mixed before the orders by the applicator 23, 30 on the fibrous web 33 with at least one further stream 21 to form a coating medium 22, as described in Figure 1. The further stream 21 may be a starch solution. In the direction of production 32 after the dryer section 27, that is at the end or after the dryer section, a further application device 23 is provided, which is designed as a coating application device 31 for applying a paint stroke. The filler stream 18 can be added directly to the coating application device 31 or before the orders by the applicator 23, 31 on the fibrous web 33 with at least one further stream 21 to Forming a coating medium 22, as described in Figure 1, mixed. The mixing can be carried out in a mixing device 20 or also in a treatment plant 20. The processing plant 20 may be formed, for example, by the coating kitchen for the preparation of a coating color or a glue application medium. The filler stream 18 is part of the application medium. As a result, the possible negative influences of the fillers of the filler stream 18 on the quality of the surface-treated fibrous web 33 can be counteracted. In the present example, the filler stream 18 is both the

Glue applicator 30 and the coating application device 31 fed directly or indirectly via a mixing device 20. However, it is also possible, the filler flow 18 only between the pre-drying section 28 and the

Nachrockenpartie 29 on the fibrous web 33 abandon or only at the end or after the dryer section 27th

LIST OF REFERENCES

device

raw material

Securities Committee

Stock preparation

treatment stage

further treatment stage

thickening stage

constant part

grinding stage

dissolver

suspension stream

washing stage

Filler fines stream

Pulp suspension flow

separation stage

Füllstoffstrom

Fine material flow

Mixing device, treatment plant further material flow

application medium

applicator

headbox

forming section

press section

drying section

pre-dryer

Afterdryers

glue application

String applicator 32 production direction

33 fibrous web

Claims

claims

A process for producing a surface-treated fibrous web (33), in particular a cardboard or packaging paper web, comprising at least a stock preparation (4), at least one headbox (24), a forming section (25) and a dryer section (27) for a paper machine for forming the fibrous web (33), wherein

an at least partially recovered paper with fillers and fines,

in particular OCC, containing fibrous raw material (2) and / or in the process for producing a fibrous web (33) resulting paper broke (3) a dissolving device (11) of the stock preparation (4) fed there and at least one suspension stream (12) is formed and this one washing step (13) for the separation of fillers and

Fines to form a filler-Feinstoffstromes (14) and a pulp suspension stream (15) is supplied and wherein the filler and feinstoffarm pulp suspension stream (15) the at least one headbox (24) is fed and the filler-fine material stream (14) in a separation stage (17) into a filler stream (18) and a fines stream (19) is separated and the filler stream (18) for surface treatment of the fibrous web (33) is applied at least on one side of the fibrous web (33).

2. The method according to claim 1,

characterized in that

the separation in the washing stage (13) is carried out in such a way that in the filler fine material stream (14) the filler mass fraction is equal to or more than 45%, preferably 50% to 70% and the mass fraction is less than or equal to 55%, in particular 30% to 50% is.

3. The method according to claim 1 or 2,

characterized in that the separation in the separation stage (17) is carried out in such a way that

Filler stream (18) the filler mass fraction is more than 50%, preferably more than 60%, particularly preferably more than 70%, in particular more than 80% and in the fines stream (19) the filler mass fraction is less than 50%.

4. The method according to any one of the preceding claims,

characterized in that

the fines stream (19) of the dissolving device (11) or the

Pulp suspension stream (15) is supplied.

5. The method according to any one of the preceding claims,

characterized in that

the filler stream (18) is thickened.

6. The method according to any one of the preceding claims,

characterized in that

the filler stream (18) for application to the fibrous web (33) of a coating application device (31), in particular a curtain applicator or a spray applicator or a film applicator or a blade applicator, is supplied.

7. The method according to any one of the preceding claims,

characterized in that

the filler stream (18) for application to the fibrous web (33) of a glue application device (30), in particular a film applicator or a size press is supplied.

8. The method according to any one of the preceding claims,

characterized in that

the filler stream (18) before the jobs on the fibrous web (33) at least one further stream (21) to form a

Application medium (22) is mixed.

9. The method according to claim 8,

characterized in that

the at least one further stream (22) comprises a starch solution or a starch solution with pigments.

10. The method according to claim 8 or 9,

characterized in that

the at least one further stream (22) one or more

Components from the following group include: synthetic binders such as styrene butadiene latex or acrylic latex; natural binders such as starch, casein; white pigments; Aids to

Adjustment of the physical properties of the application medium.

1 1 .Method according to one of the preceding claims 8 to 10,

characterized in that

the application medium (22) is used to apply a color stroke.

12. The method according to claim 8 to 10,

characterized in that

the application medium (22) is used to apply a glue application.

13. The method according to any one of the preceding claims,

characterized in that

the filler stream (18) after the drying process in the dryer section (27) and / or within the drying process of the dryer section (27) is applied.

14. Device (1) for carrying out the method according to claim 1 for producing a surface-treated fibrous web (33), in particular a cardboard or packaging paper web, at least comprising a stock preparation (4), at least one headbox (24), a Formierpartie (25) and a drying section (27) for a paper machine for forming the fibrous web (33), a dissolving device (11) in the stock preparation (4) for feeding a fibrous containing at least partially recovered paper with fillers and fines, in particular OCC

Raw material (2) and / or in the production of a coated fibrous web (33) resulting paper broke (3) and to form at least one suspension stream (12), a washing stage (13) for the separation of fillers and fines from the suspension stream (12) Forming a filler-Feinstoffstromes (14) and a filler and feinstoffarmmen pulp suspension stream (15), wherein the pulp suspension stream (15) is guided in a conduit which is connected to the at least one headbox (24), a separation stage (17) for separation the filler-fine material stream (14) into a filler stream (18) and a fine material stream (19) and an applicator device (23) for at least one-sided applications of the filler stream (18) on the fibrous web (33).

15. Device according to claim 14,

characterized in that

the application device (33) is a coating application device (31) and / or a glue application device (30).