EP3404140B1 - Transfer or shoe press belt for a paper machine, use of the belt in a paper machine and method for producing the belt - Google Patents

Description

The invention relates to a transfer or shoe press belt for a paper machine and the use of a transfer or shoe press belt in such. Moreover, the invention relates to a method for producing a transfer or shoe press belt for a paper machine.

Modern paper machines are reaching ever higher speeds. The high speeds require that the paper web is at no point without support when passing through the press and dryer section of the paper machine. In the press section, a complete support of the paper web with the help of circulating press felts in most cases is not given. In order to guide the paper web even in the areas in which there is no support from the press felt - this is particularly true for the transition area to the dryer section - so-called transfer belts are used, the paper web by one or more presses of the press section together with the lead each associated press felt and lead after detachment of the press felt from the paper web to a point where the paper web is usually removed with the aid of a suction roll from the transfer belt and taken over by a circulating in the dryer section dryer. Examples of the guide of transfer belts in the press section of a paper machine are the FIGS. 1 to 3 the EP 0 576 115 A1 refer to.

In the further figures and the associated description of this document, a transfer belt is described, which has a fabric-formed carrier, which ensures the structural strength of the transfer belt. On the intended for the plant of the paper web flat side is a coating of a polymeric material, such as an acrylic or polyurethane resin, provided, in which the carrier fabric is partially embedded. On the other flat side can be pinned on the carrier, a fiber fleece.

In particular, in tissue paper machines, transfer and shoe press belts are also used, by means of which the paper to be produced is generally pressed against a drying cylinder, in particular a Yankee cylinder of the machine.

The EP 1 870 514 A2 discloses a conveyor belt for a paper machine comprising a carrier embedded in a building material, such as a polymeric material, and having structuring on the machine side due to grooves provided thereon.

From the EP 1 225 272 A1 goes out a shoe press belt, which paper side has a cover layer, which is first ground in the production and in which then grooves are introduced, whereby a structuring is obtained.

The EP 2 157 233 A1 discloses a shoe press belt for a paper machine, which is provided on the paper side with a cover layer into which grooves are introduced by means of a cutting tool and which is then polished with sandpaper.

The EP 1 085 125 A2 discloses a transfer belt which has on the paper side a high molecular weight elastic element in which microcapsules are embedded and which is ground so that cut microcapsules are obtained on the paper side and structuring results.

The EP 0 939 162 A2 discloses a shoe press belt having on paper side a polyurethane resin layer which is first polished to obtain a desired thickness and into which concave grooves are subsequently inserted.

The WO 99/31318 A1 discloses a papermaking belt having a backing and a structured cover layer with ridges and depressions on the paper side, wherein the structuring of the cover layer corresponds to a structuring of the woven fabric backing which is deposited therein.

The US 2006/234575 A1 discloses a belt for a papermaking machine having a backing coated with polymer resin on both sides with grooves on the paper side to provide relief and dimple patterning. The coating is applied by a thermal spray process.

The previously known transfer and shoe press belts have proven themselves in principle. However, there is still a need for improved transfer or shoe press belts. In particular, there is a need for tapes which can be produced with comparatively little effort, are at the same time characterized by a comparatively long service life and optimum operating characteristics and by means of which, in particular, also paper with an embossing, For example, embossed tissue paper can be obtained and / or that allows improved control of the water balance.

This object is achieved by a transfer or shoe press belt, suitable for use in a paper machine, with a paper side intended for supporting a paper or felt web and a side facing away from the paper side, and with a carrier, wherein the transfer or shoe press belt Furthermore, a structured cover layer arranged on the paper side of the support, which consists of a coating material comprising or consisting of at least one polymer, in particular polyurea and / or polyurethane, and at least on its side facing away from the support by a structured surface having a plurality of elevations and depressions characterized and ground on its side facing away from the carrier, wherein the structured top layer was obtained in particular by the coating material was applied by a spray or curtain application or extrusion process,
or furthermore comprises a structured cover layer arranged on the machine side of the support, which consists of a coating material comprising or consisting of at least one polymer, in particular polyurea and / or polyurethane and at least on its side facing away from the support by a structured surface with a plurality of elevations and Recesses, and is ground on its side facing away from the carrier, wherein the structured top layer was obtained in particular by the coating material was applied by a spray or curtain application or extrusion process,
or furthermore comprises a structured covering layer which is arranged on the machine side and on the paper side and which consists of a coating material comprising or consisting of at least one polymer, in particular polyurea and / or polyurethane, and at least on its side remote from the support by a structured surface having a multiplicity distinguished by elevations and depressions, and are ground on their side facing away from the carrier, wherein the paper-side and the machine-side structured cover layer in particular was obtained by applying the coating material by a spray or curtain application or extrusion process
wherein the paper-side and / or machine-side structured cover layer coating material is made of a reactive multi-component system having two or more elastomeric coating-producing components, and the paper-side and / or machine-side structured cover layer coating material is one is characterized by a viscosity of less than 3000 mPa s at a lying in the range of 20 ° C to 120 ° C, in particular 60 to 90 ° C processing temperature.

• ein Träger bereitgestellt wird,
• und bei dem zusätzlich papierseitig des Trägers eine strukturierte Deckschicht aus einem wenigstens ein Polymer, insbesondere Polyharnstoff und/oder Polyurethan umfassenden oder hieraus bestehenden Beschichtungsmaterial hergestellt wird, die sich zumindest an
• ihrer von dem Träger abgewandten Seite durch eine strukturierte Oberfläche mit einer Vielzahl von Erhebungen und Vertiefungen auszeichnet, wobei die strukturierte Deckschicht insbesondere hergestellt wird, indem Beschichtungsmaterial durch ein Sprüh- oder Vorhang-Auftrags- oder Extrusions-Verfahren aufgebracht wird, und die strukturierte Deckschicht derart geschliffen wird, dass die Höhe der Erhebungen reduziert jedoch keine glatte Oberfläche erhalten wird,
• oder bei dem zusätzlich maschinenseitig des Trägers eine strukturierte Deckschicht aus einem wenigstens ein Polymer, insbesondere Polyharnstoff und/oder Polyurethan umfassenden oder hieraus bestehenden Beschichtungsmaterial hergestellt wird, die sich zumindest an ihrer von dem Träger abgewandten Seite durch eine strukturierte Oberfläche mit einer Vielzahl von Erhebungen und Vertiefungen auszeichnet, wobei die strukturierte Deckschicht insbesondere hergestellt wird, indem Beschichtungsmaterial durch ein Sprüh- oder Vorhang-Auftrags- oder Extrusions-Verfahren aufgebracht wird, und die strukturierte Deckschicht derart geschliffen wird, dass die Höhe der Erhebungen reduziert jedoch keine glatte Oberfläche erhalten wird,
• oder bei dem zusätzlich papier- und maschinenseitig des Trägers eine strukturierte Deckschicht aus einem wenigstens ein Polymer, insbesondere Polyharnstoff und/oder Polyurethan umfassenden oder hieraus bestehenden Beschichtungsmaterial hergestellt wird, die sich zumindest an ihrer von dem Träger abgewandten Seite durch eine strukturierte Oberfläche mit einer Vielzahl von Erhebungen und Vertiefungen auszeichnet, wobei die papier- und die maschinenseitige strukturierte Deckschicht insbesondere hergestellt wird, indem Beschichtungsmaterial durch ein Sprüh- oder Vorhang-Auftrags- oder Extrusions-Verfahren aufgebracht wird, und die papier- und die maschinenseitige strukturierte Deckschicht derart geschliffen wird, dass die Höhe der Erhebungen reduziert jedoch keine glatte Oberfläche erhalten wird,
  wobei zum Erhalt des Beschichtungsmaterials für die papierseitige und/oder maschinenseitige strukturierte Deckschicht ein reaktives Mehrkomponenten-System mit zwei oder mehr Komponenten zur Herstellung einer Elastomer-Beschichtung verwendet wird, und für die papierseitige und/oder maschinenseitige strukturierte Deckschicht ein Beschichtungsmaterial verwendet wird, das sich durch eine Viskosität von weniger als 3000 mPa s bei einer im Bereich von 20°C bis 120°C, insbesondere 60 bis 90°C liegenden Verarbeitungstemperatur auszeichnet.

In addition, the object is achieved by a method for producing a transfer or shoe press belt which is suitable for use in a paper machine and has a paper page intended for the support of a paper or felt web and a machine side facing away from the paper side, in particular a transfer according to the invention - or shoe press belt, in which

• a carrier is provided,
• and in which additionally on the paper side of the support a structured covering layer is produced from a coating material comprising or consisting of at least one polymer, in particular polyurea and / or polyurethane, which at least adjoins
• their side facing away from the carrier by a structured surface having a plurality of elevations and depressions, wherein the structured covering layer is in particular produced by coating material by a spray or curtain application or extrusion process is applied, and the structured cover layer is ground such that the height of the elevations is reduced but no smooth surface is obtained,
• or in which, in addition to the machine side of the carrier, a structured covering layer is produced from a coating material comprising or consisting of at least one polymer, in particular polyurea and / or polyurethane, which at least on its side facing away from the carrier by a structured surface with a plurality of elevations and Specializes in depressions, in particular, the structured cover layer is produced by applying coating material by a spray or curtain application or extrusion method, and the structured cover layer is ground such that the height of the projections is reduced but no smooth surface is obtained;
• or in which additionally a paper and machine side of the carrier, a structured cover layer of at least one polymer, in particular polyurea and / or polyurethane comprehensive or existing coating material is made, at least on its side facing away from the carrier by a structured surface having a plurality characterized by embossments and depressions, wherein the paper and the machine-side structured cover layer is in particular produced by applying coating material by a spray or curtain application or extrusion method, and the paper and the machine-side structured cover layer is ground in such a way, that the height of the elevations is reduced but no smooth surface is obtained,
  wherein, to obtain the coating material for the paper-side and / or machine-side structured cover layer, a reactive multicomponent system with two or more components is used to produce an elastomer coating, and a coating material is used for the paper-side and / or machine-side structured cover layer by a viscosity of less than 3000 mPa s at a temperature in the range of 20 ° C to 120 ° C, especially 60 to 90 ° C lying processing temperature.

It has been found that a transport or shoe press belt designed in the manner according to the invention has a paper and / or machine-side structured polymer, in particular polyurea and / or polyurethane coating with a surface structure having a multiplicity of elevations and depressions has, which is ground so that at least a portion of the elevations has planar top sides, which are at least substantially in one plane, on the one hand excellent for the production of embossed paper, especially tissue paper and on the other hand provides a way to control the water balance. The grinding is carried out according to the invention such that the elevations of Flattened structure on the top side, but the structure is not completely leveled, so that no consistently flat or consistently smooth surface without elevations and depressions is obtained.

In the presence of a paper-side textured cover layer, the flat top surfaces of the bumps due to grinding provide a good and generally sufficient contact surface for pressing the paper and, together with the areas lying between the flattened bumps facing these wells, have a surface topography of the transfer belt. which results in an embossing pattern of the paper produced with a paper machine equipped with the transfer belt according to the invention. A paper-side structuring can also serve to control the water balance, in particular in the event that a band designed according to the invention serves as a shoe press belt and the paper side is correspondingly brought into contact with a felt.

By means of a textured covering layer present on the machine side, the water balance can also be controlled, for example a "hydroplaning" can be prevented and water and impurities can be removed well. In addition, a machine-side polymer coating can provide protection in the area of the belt contact with the machine and thus ensure a long service life. In particular, in the case that a designed band according to the invention serves as a shoe press belt, a structured machine side can also serve to control the lubricating film between the shoe and the machine side of the belt.

Depending on the field of application, the strip according to the invention can have a structured cover layer only on the paper or only on the machine side or also on the paper side and the machine side. Is only one Provided a textured cover layer side, can of course be provided on the opposite side and a non-structured, so smooth cover layer of the same or from another coating material. In this case, both on the paper side a smooth and on the machine side a structured cover layer and on the paper side a structured and on the machine side a smooth cover layer can be provided. If several layers are present on one side, the top layer is to be understood as meaning, in particular, in each case the topmost layer.

A structured paper and / or machine-side surface of the transfer belt is preferably provided by a patterning of a structured carrier penetrating into the paper or machine-side cover layer or by a structured intermediate layer arranged between carrier and paper-side cover layer and / or between carrier and machine-side cover layer , The structured cover layer provided on one or both sides adheres to the structure of the carrier or interlayer surface and forms it quasi alienated material-building.

Accordingly, according to a preferred embodiment of the tape according to the invention, it is provided that a paper-side structured cover layer is provided, and a structured intermediate layer arranged between the support and the paper-side structured cover layer is provided from a coating material comprising or consisting of at least one polymer, in particular polyurea and / or polyurethane is, which is characterized at least on its side facing away from the carrier by a structured surface having a plurality of elevations and depressions. Alternatively it can be provided that a structured surface layer on the machine side and a structured one arranged between the carrier and the machine-side structured cover layer Intermediate layer is provided from a coating material comprising or consisting of at least one polymer, in particular polyurea and / or polyurethane, which is distinguished at least on its side facing away from the carrier by a structured surface with a plurality of elevations and depressions. Again alternatively it can be provided that a paper and a machine-side structured cover layer is provided, and paper and / or machine side arranged between the support and the respective structured cover layer structured intermediate layer of at least one polymer, in particular polyurea and / or polyurethane comprehensive or existing coating material is provided, which is characterized at least on its side facing away from the carrier by a structured surface having a plurality of elevations and depressions.

In the method according to the invention can be provided analogously that a paper-side structured cover layer prepared and prior to their preparation on the provided carrier paper side, a structured intermediate layer of at least one polymer, especially polyurea and / or polyurethane comprehensive or existing coating material is made, at least on the paper side characterized by a structured surface having a plurality of elevations and depressions, or that a machine-side structured cover layer prepared and prior to their preparation on the provided carrier machine side a structured intermediate layer of a comprehensive at least one polymer, especially polyurea and / or polyurethane coating material or thereof is produced, which is characterized at least on the machine side by a structured surface having a plurality of elevations and depressions t, or that a paper- and a machine-side structured cover layer are produced and provided on the provided paper prior to the production of the paper-side structured cover layer Carrier paper-side, a structured intermediate layer of a at least one polymer, in particular polyurea and / or polyurethane comprising or consisting thereof coating material is produced, which is characterized at least on its side facing away from the carrier by a structured surface with a plurality of elevations and depressions, and / / or, prior to the production of the machine-side structured cover layer on the provided support, a structured intermediate layer is produced from a coating material comprising or consisting of at least one polymer, in particular polyurea and / or polyurethane, which is at least on its side remote from the support by a structured surface characterized by a variety of surveys and wells.

If a paper-side and a machine-side structured cover layer are present, a structured intermediate layer may be provided below or even below one.

In the following, further optional features are given, it being understood that these may apply both to embodiments of a tape according to the invention with, for example, only a single layer on one of the two sides, as well as to those having a plurality of layers. Furthermore, when multiple layers are provided, these features may be satisfied for only one, multiple, or even all layers.

The paper-side and / or the machine-side structured intermediate layer has been obtained, in particular, by applying the coating material to the carrier by a spray or pressure or curtain application or extrusion process. When curtain coating or curtain coating known curtain coating that is the coating material expedient manner applied in a state of suitable viscosity, in particular in the liquid state. If the coating material is sprayed on, this is done in particular flatly and / or using one or more suitable spray nozzles.

In a preferred embodiment of the band or method according to the invention, it is provided that the paper-side and / or the machine-side structured intermediate layer has been obtained or produced by paper side and / or machine side at a predetermined distance of particular 1 to 10 mm before or immediately on the Carrier arranged a carrier partially masking, preferably lattice-shaped masking and the coating material was applied to the partially hidden by the masking carrier by a spray or curtain application or extrusion process or is.

If a masking is used, provision can furthermore be made for the carrier and the masking arranged at the predetermined spacing in front of or directly on the carrier to be moved during spraying or curtain application or extrusion, the travel speed of the carrier and masking being at least substantially is equal to. By spaced, in particular "running" masking a somewhat "fuzzy" material application can be achieved and thus a coating pattern with "flowing" rather than "sharp" transitions can be obtained.

In particular, in that case that a masking paper and / or machine side is placed directly on the support, it can be provided that the removal of the masking takes place after sufficient solidification of the coating material. This can be ensured in particular be that coating material is not in the still liquid or soft state in areas in which such is not desirable.

As an alternative or in addition to using masking, it may be provided that the paper-side and / or the machine-side structured intermediate layer has been obtained by printing a predetermined pattern of the coating material as an intermediate layer on the carrier.

Both by printing a polymer pattern and the use of a masking can be obtained with little effort, a structured intermediate layer on the paper and / or the machine side, both approaches offer a high degree of flexibility, as far as the concrete form of the structure or patterning so that embossed paper with almost any embossing pattern can be obtained in a simple manner and / or a defined control of the water balance, for example, flexible different flow directions can be obtained.

It is clear that in the event that both a paper and a machine side, a structured intermediate layer is provided or manufactured, both can be prepared in the same manner, for example using a mask or both by printing, or even various of mentioned manufacturing process can be used.

If a structured intermediate layer is provided on the paper and / or machine side of the carrier, the paper and / or machine-side structured covering layer is produced in particular in such a way that the structured surface is deposited on the side of the structured intermediate layer facing away from the carrier in the structured covering layer. The invention Accordingly, in a preferred manner, the band is characterized in that the structured surface on the side of the paper-side and / or the machine-side structured cover layer facing away from the carrier is structured by the structured surface of the structured surface of the side facing away from the carrier Cover layer lying structured intermediate layer is given. This can be achieved in particular by a coating material which is characterized by a suitable viscosity, with uniform coating thickness in particular contactless - so for example by spray, curtain coating or extrusion process and not by a doctor blade or roller application - on the paper and / or machine side applied with the intermediate layer so that it follows the structure of the intermediate layer, escapes in particular the coating matrix, so to speak into the recesses of the intermediate layer. It has been found that polyureas are particularly suitable for obtaining, with uniform application, a cover layer whose structure resembles or resembles that of an underlying intermediate layer or else an underlying support.

A further embodiment of the method according to the invention is characterized in that a carrier is provided which has a structured surface with a multiplicity of elevations and depressions on the paper and / or machine side, and in particular the paper side and / or the machine side structured cover layer directly on the carrier and the paper-side and / or the machine-side structured cover layer is produced in such a way that the structure of the paper- or machine-side surface of the support is reflected in the paper- or machine-side surface of the structured cover layer. A further embodiment of the tape according to the invention is characterized accordingly by the fact that the carrier paper and / or machine side a structured surface having a plurality of elevations and depressions, and in particular the paper side and / or the machine side structured cover layer is arranged directly on the carrier and the structured surface on the side facing away from the carrier side of the paper side and / or the machine side structured cover layer the paper or machine-side structured surface of the carrier which deposits in the structured covering layer is given. If no structured intermediate layer is provided on the paper and / or machine side, the paper and / or machine-side structured cover layer is produced directly on the support, in particular by applying coating material to the corresponding side of the support by means of a spray application or extrusion Method is applied to these.

A carrier with a structured surface may for example be in the form of a fabric, in particular a fabric with at least some coarser and preferably more prominent tissue threads. As for the transfer ribbon according to the invention particularly suitable tissue carrier with pronounced structure, in the DE 20 2013 104 888 U1 , the contents of which are hereby incorporated by reference, disclosed various embodiments of a fabric for a paper machine.

As an alternative to the carrier being given through a fabric or a fabric being provided as a carrier, it is also possible for a spiral link belt or a knitted fabric or a thread lay to be provided as a carrier. Depending on the nature of the carrier, coating material applied on the paper and / or machine side can enter or pass through the carrier completely.

In particular, in that case that the carrier has a surface structuring with elevations and depressions on at least one side, the provision of a structured intermediate layer can also be dispensed with and the tape according to the invention then in particular have only a paper-side coating and / or only a machine-side coating or in particular, only one can be produced in the context of the method according to the invention on one or both sides. However, this is not meant to be limiting. This means that a structured intermediate layer, ie more than one layer of a coating material comprising or consisting of at least one polymer, in particular polyurea and / or polyurethane, can also be provided on paper and / or machine side on a support which is not at least substantially smooth or be. Regardless of which type of support is used, in principle further layers, for example one or more smooth cover and / or intermediate layers of the same or of other materials may be provided both on paper and on the machine side.

In a development of the strip according to the invention, it is further provided that the paper-side and / or the machine-side structured cover layer is formed as a closed layer extending over the entire paper side or machine side of the tape and / or the paper-side and / or the machine-side structured intermediate layer is not a closed layer is formed but has interruptions. The method according to the invention can accordingly be distinguished by the fact that a closed paper-side and / or machine-side structured cover layer extending over the entire paper side of the transfer belt is produced and / or a paper-side and / or machine-side structured intermediate layer which is not closed but has interruptions is produced.

A paper-side and / or machine-side structured cover layer is closed in particular when a paper-side and / or machine-side structured intermediate layer has been intermittently produced, for example using masking and / or by printing the coating material according to a predetermined pattern, and an impermeable one Band should be obtained. The paper-side and / or machine-side structured intermediate layer then serves, in particular, the paper or machine-side structuring and the structured cover layer, which in particular lies directly above it, to close the tape while maintaining the structure.

The paper-side and / or machine-side structured cover layer and / or the paper-side and / or machine-side structured intermediate layer is impermeable to water in a further preferred embodiment, in the context of the method may be provided accordingly that a water-impermeable paper-side and / or machine-side textured cover layer and / or a waterproof paper-side and / or machine-side structured intermediate layer is produced.

As regards the coating material for the paper-side and / or machine-side structured covering layer and / or possibly existing paper-side and / or machine-side structured intermediate layer and / or further layers which may be present on the paper and / or machine side, such have proven to be particularly suitable produced from a reactive system for producing an elastomer coating, preferably a multicomponent system having two or more components, which in particular has a pot life of less than 30 Seconds, preferably less than 15 seconds, more preferably less than 10 seconds.

Reactive systems cure by cross-linking the reactive groups in the components. Under the pot life is to be understood that time within which the mixed starting materials are still flowable. In particular, the pot life according to DIN 16 945 is meant. Polyurea polymers, for example, are generally produced via a two-component system, one component, in particular an isocyanate, reacting with a polyfunctional amine or amine mixture as a further component to form polyurea.

By way of example, two-component systems for obtaining the coating material may be mentioned: isocyanate-containing prepolymer which reacts with polyamine to form polyurea or with polyalcohol (polyol) to give polyurethane. The coating material of the paper and / or machine-side structured cover layer is one which is characterized by a viscosity of less than 3000 mPas, preferably less than 1000 mPas, in a range of 20 ° C. to 120 ° C., especially 60 to 90 ° C lying processing temperature.

The coating material of the paper and / or machine-side structured intermediate layer and / or other layers present on the paper and / or machine side may in particular be one which is preferred by a viscosity of less than 3000 mPa s less than 1000 mPa s at a lying in the range of 20 ° C to 120 ° C, in particular 60 to 90 ° C processing temperature. A viscosity of the coating material in this area has proven to be particularly suitable, in particular for a spray or Curtain application. As far as the determination of viscosity is concerned, particular reference should be made to ISO 3219: 1993.

Polyurea is preferably processed at a temperature of 60 to 90 ° C and is characterized in this temperature range by a viscosity of less than 1000 mPa s.

The coating material of the paper-side and / or machine-side structured cover layer and / or the paper-side and / or machine-side structured intermediate layer and / or any further layers present comprises in particular polyurea and / or polyurethane and / or epoxy resin or consists thereof.

The layer thickness of the paper-side and / or machine-side structured cover layer and / or the paper-side and / or machine-side structured intermediate layer and / or any further layers present is in particular adjusted such that it lies in the range from 1 to 5 mm.

The features mentioned above for a structured covering layer, in particular the said materials, the said layer thickness and the water-impermeable nature, can of course also be used for the smooth covering layer in the case where a structured covering layer is provided on one side and a smooth covering layer on the other side. each alone or in combination - apply.

Another object of the invention is the use of a belt according to the invention as a press belt, in particular transfer or shoe press belt in a paper machine, in particular a tissue paper machine, preferably in such a way that guided through the paper machine paper or felt web in contact with the paper side of Bandes comes, and / or in particular in the production of embossed paper, preferably embossed tissue paper.

The transfer or shoe press belt according to the invention is also particularly well suited for use in a paper machine for the production of tissue paper, wherein the use preferably takes place in such a way that pressed the paper to be produced by means of the tape according to the invention against a drying cylinder, in particular a Yankee cylinder of the paper machine becomes.

Figur 1

eine erste Ausführungsform eines erfindungsgemäßen Transferoder Schuhpressenbandes in rein schematischer Schnittdarstellung,

Figuren 2 bis 5

die einzelnen Schritte bei der Durchführung einer Ausführungsform des erfindungsgemäßen Verfahrens zur Herstellung des Bandes aus Figur 1,

Figur 6

eine zweite Ausführungsform eines erfindungsgemäßen Transfer- oder Schuhpressenbandes in rein schematischer Schnittdarstellung, und

Figur 7

das Band aus Figur 6 vor dem Schleifen der Deckschicht.

In the drawing, the invention is illustrated by means of exemplary embodiments. Show it:

FIG. 1

a first embodiment of a transfer or shoe press belt according to the invention in a purely schematic sectional view,

FIGS. 2 to 5

the individual steps in carrying out an embodiment of the method according to the invention for the production of the tape FIG. 1 .

FIG. 6

a second embodiment of a transfer or shoe press belt according to the invention in a purely schematic sectional view, and

FIG. 7

the tape off FIG. 6 before sanding the topcoat.

The FIG. 1 shows a purely schematic sectional view of a section of a transfer or shoe press belt according to the invention, which is suitable for use in a paper machine for the production of embossed paper, in particular embossed tissue paper.

The transfer or shoe press belt has a specific for the edition of a paper web paper side 1, in the FIG. 1 facing upward, and a side facing away from the paper side 1 machine side 2 and comprises a present given by a spiral link belt carrier 3. The smooth machine side 2 of the carrier 3 forms the machine side 2 of the band. On the paper side of the carrier 3, a cover layer 4 of polyurea is provided, which is paper-characterized by a structured surface with a plurality of elevations 5 and depressions 6 and ground paper, so that all of the elevations 5 are characterized by a comparatively flat top. Between the cover layer 4 and the carrier 3, an intermediate layer 7 is further provided, which also consists of polyurea and paper side characterized by a structured surface with a plurality of elevations 5 and depressions 6. The intermediate layer 7 is particularly in the FIG. 4 recognizable, where the carrier 3 is shown with paper side disposed thereon intermediate layer 7, but still without top layer 4.

For the production of in the FIG. 1 illustrated transfer or shoe press belt according to the invention, the spiral link belt is provided as a carrier 3 in a first step and on this paper side a grid-shaped masking 8 is placed directly so that it is in contact with the carrier 3. The carrier 3 with paper side disposed thereon masking 8 is in the FIG. 2 shown.

In a next step, on the paper side partially covered by the masking 8 carrier 3, the intermediate layer 7 is prepared by a polyurea is sprayed onto the carrier 3 arranged thereon with masking 8 in the liquid state. For the preparation of the polyurea used in the illustrated embodiment, a two-component system for producing an elastomeric coating for Commitment. Specifically, an isocyanate-containing prepolymer is mixed with polyamine to react to form polyurea. The mixture takes place immediately before spraying onto the carrier 3, so that the coating material can still be applied to the carrier 3 within the pot life, ie before completion of the reaction and thus curing of the coating material. In the illustrated embodiment, the coating material is sprayed by means of one or more nozzles not shown in the figures. The mixture of the two components for the preparation of the polyurea takes place in the nozzle or the nozzles. The pot life of the coating material used in the present case is about ten seconds. The processing temperature is in the present case at about 70 ° C. At this temperature, the material used has a viscosity of less than 1000 mPa s. The carrier 3 with masking 8 arranged thereon is guided past the nozzle for coating with polyurea for producing the intermediate layer 7. Alternatively, the nozzle used can be moved by hand or by machine. The spraying of coating material takes place such that an intermediate layer 7 of constant thickness with a thickness of about 2 mm is obtained. The state after spraying the coating material is in FIG. 3 shown.

It should be noted that as an alternative to the illustrated embodiment, in which the masking 8 was placed directly on the paper side of the carrier 3, this can also be arranged at a predetermined distance of a few, for example 5 mm to the paper side of the carrier 3 and, if the carrier 3 is moved during the application of the coating material, in particular can "run along" with this, preferably at the same speed. Due to a distance between the masking 8 and the carrier 3, in particular in connection with an application of coating material by spraying, a rather "blurred Masking "and thus a coating pattern with quasi" flowing transitions "instead of clear boundary contours are obtained.

Furthermore, as an alternative to a spraying of the coating material, for example, a curtain application process can be used, so the two mixed components can be poured in the liquid state within the pot life curtain-like on the support 3 with arranged on it 8 masking. If curtain application is used, the carrier 3 is moved, in particular in a manner known per se, under the "curtain" formed from the coating material, in particular in a direction orthogonal to the plane formed by the curtain.

A structured intermediate layer 7 can furthermore furthermore be obtained alternatively by directly printing coating material on the paper side of the carrier in a defined application pattern, for example by means of material-constructing printing processes.

Following the spraying - or alternatively used application method - the masking 8 is removed, wherein the removal in the illustrated embodiment takes place after the curing of the coating material. The result, so the carrier 3 with intermediate view 7 produced thereon, is in the FIG. 4 shown.

In a penultimate step, the cover layer 4 is applied to the carrier 3 with intermediate layer 7 produced thereon, wherein the same coating material is used and the application takes place again by spraying and also under the operating parameters mentioned above for the preparation of the intermediate layer 7, and wherein the only difference to the previous procedure is that this time no masking 8 is used. The spraying of coating material again in such a way that a cover layer 4 of constant thickness is obtained with a thickness of about 2 mm.

With regard to the production of the cover layer 4, it should also be noted that this does not have to be obtained by spraying coating material, but can also be obtained, for example, by curtain application or else extrusion.

The resulting state is in the FIG. 5 shown. For the sake of simplicity, the FIG. 5 - just like that FIG. 1 no dividing line between the cover layer 4 and the intermediate layer 7. However, the cross section of the cover layer 4 is based on the comparison of FIGS FIGS. 1 and 4 out.

As can also be seen from the figures, the structure of the intermediate layer 7 is reflected in the cover layer 4 applied thereto. In contrast to the intermediate layer 7, which does not represent the carrier 3 completely covering continuous layer, but, as in particular in FIG. 4 recognizable, has interruptions, the cover layer 4 produced without the use of a mask 8 is formed as a closed layer. The cover layer 4 of in FIG. 1 illustrated embodiment of a tape according to the invention is thus impermeable to water.

In a final step, the cover layer 4 is ground on the paper side, so that elevations 5 are obtained with a flat top, which provide a particularly suitable contact surface for the pressing operation of the paper to be produced.

Alternatively to the illustrated embodiment, in which the machine side of the belt is formed by the machine side 2 of the carrier 3, On the machine side 2 of the carrier 3, it is also possible to provide a machine-side, in particular structured, cover layer 4 and optionally a machine-side, in particular, structured intermediate layer 7 lying underneath it. A machine-side cover layer and machine-side interlayer can be made in complete analogy to a paper-side cover and interlayer, as described in detail above. If one or more machine-side layers are provided, they may consist of the same or a different material as the intermediate layer 7 and / or cover layer 4. Of course, it is also possible that only on the machine side 2 of the carrier 3, a cover layer 4 and possibly an intermediate layer 7 are provided.

In the FIGS. 6 and 7 is - also in a purely schematic sectional view of a portion - a second embodiment of a transfer or shoe press belt according to the invention shown. This also comprises a support 3, which, however, is given by a fabric. Both the paper and the machine side are characterized by a pronounced fabric structure, which in the FIGS. 6 and 7 is indicated schematically.

In contrast to the first embodiment of the FIGS. 1 to 5 The tape shown here has no intermediate layer 7 but only a covering layer 4 of polyurea, which is ground on the paper side.

While the FIG. 6 shows the second embodiment of the transfer or shoe press belt in the finished state, the can FIG. 7 the unpolished state can be taken.

The tape according to the second embodiment is produced by providing a fabric carrier 3 and on which the cover layer 4 is produced by using the same material as described above in connection with FIG described first embodiment for intermediate and top layer 4, is sprayed onto the paper side of the fabric carrier 3 without a masking 8 is thereby used.

The structured paper-side surface of the cover layer 4 is obtained in the second embodiment, characterized in that the fabric structure of the carrier 3 in the cover layer 4 - as in the FIGS. 6 and 7 recognizable - precipitate. The cover layer 4 adheres to the structure of the carrier surface and forms this quasi "alienated" material-building from.

The layer thickness of the cover layer 4 is also about 2 mm and this is formed as a continuous layer without interruptions, so that the cover layer 4 of the second embodiment is waterproof.

It should also be noted with regard to the second exemplary embodiment that, in addition to this, in addition to the paper side or else only on the machine side of the carrier 3, it is possible to provide a particularly structured cover layer 4 and optionally underlying intermediate layer 7.

Furthermore, it is also possible that both in the first and in the second embodiment, a smooth cover layer is provided on the machine side 2, or that the structured cover layer 4 is not provided on the paper-1 but the machine side 2 and on the paper side 1 is a smooth topcoat. The smooth cover layer can then consist of the same coating material as the structured and the same layer thickness and hardness, which is not to be understood as limiting, so also cover layers can be provided on opposite sides, not only by their surface texture but also other features differ.

The above-described embodiments of a transfer or shoe press belt according to the invention are used in particular in the press section of a paper machine in the region of the transition to the dryer section, where they are due to their structured paper-side surface of the production of embossed paper, in particular embossed tissue paper. The use can also be made such that the paper to be produced is pressed by means of the tape according to the invention against a drying cylinder, in particular a Yankee cylinder of the paper machine.

The strip according to the invention can be produced in a simple manner by carrying out the method according to the invention, whereby both using a masking 8 and during the production of the intermediate layer 7 by printing a very great flexibility, as regards the available structures of the transfer ribbon and thus produced embossed paper ,

Claims (17)

1. Transfer or shoe press belt, suitable for use in a paper machine, with a paper side (1) intended for supporting a paper or felt web and a machine side (2) facing away from the paper side (1), and with a carrier (3), wherein the transfer or shoe press belt
   further comprises a structured cover layer (4) arranged on the paper side of the carrier (3), which consists of a coating material comprising or consisting of at least one polymer, in particular polyurea and/or polyurethane, and which is at least on its side facing away from the carrier (3) characterized by a structured surface having a plurality of elevations (5) and depressions (6), and is ground on its side facing away from the carrier (3),
   or further comprises a structured cover layer (4) arranged on the machine side of the carrier (3), which consists of a coating material comprising or consisting of at least one polymer, in particular polyurea and/or polyurethane, and which is at least on its side facing away from the carrier (3) characterized by a structured surface having a plurality of elevations (5) and depressions (6), and is ground on its side facing away from the carrier (3),
   or further comprises a structured cover layer (4) arranged on the machine side and on the paper side of the carrier (3), which consist of a coating material comprising or consisting of at least one polymer, in particular polyurea and/or polyurethane, and which are at least on their side facing away from the carrier (3) characterized by a structured surface having a plurality of elevations (5) and depressions (6), and are ground on their side facing away from the carrier (3),
   wherein the coating material of the paper side and/or the machine side structured cover layer (4) has been produced from a reactive multicomponent system with two or more components for producing an elastomer coating, and the coating material of the paper side and/or the machine side structured cover layer (4) is such that it is characterized by a viscosity of less than 3000 mPa s at a processing temperature in the range from 20°C to 120°C, in particular from 60°C to 90°C.
2. Belt according to claim 1, characterized in that
   a paper side structured cover layer (4) is provided, and a structured intermediate layer (7) from a coating material comprising or consisting of at least one polymer, in particular polyurea and/or polyurethane, which is arranged between the carrier (3) and the paper side structured cover layer (4) is provided, which is characterized at least on its side facing away from the carrier (3) by a structured surface having a plurality of elevations (5) and depressions (6),
   or a machine side structured cover layer (4) is provided, and a structured intermediate layer (7) from a coating material comprising or consisting of at least one polymer, in particular polyurea and/or polyurethane, which is arranged between the carrier (3) and the machine side structured cover layer (4) is provided, which is characterized at least on its side facing away from the carrier (3) by a structured surface having a plurality of elevations (5) and depressions (6),
   or a paper and a machine side structured cover layer (4) is provided, and on the paper and/or machine side a structured intermediate layer (7) from a coating material comprising or consisting of at least one polymer, in particular polyurea and/or polyurethane, which is arranged between the carrier (3) and the respective structured cover layer (4) is provided, which at least at its side facing away from the carrier (3) has a structured surface with a plurality of elevations (5) and depressions (6).
3. Belt according to claim 2, characterized in that the structured surface on the side of the paper side and/or the machine side structured cover layer (4) that faces away from the carrier (3) is given by a structured surface of the side facing away from the carrier (3) of an intermediate structured layer (7) being disposed below the cover layer (4) that penetrates into the respective structured cover layer (4).
4. Belt according to one of the preceding claims, characterized in that the carrier (3) is a spiral link belt or a woven fabric or a knitted fabric or a scrim and/or in that the carrier (3) has on the paper and/or machine side a structured surface with a plurality of elevations (5) and depressions (6), and in particular the paper side and/or the machine side structured cover layer (4) is arranged directly on the carrier (3), and the structured surface on the side of the paper side and/or the machine side structured cover layer (4) facing away from the carrier (3) is given by the paper or machine side structured surface of the carrier (3) penetrating into the structured cover layer (4).
5. Belt according to one of the preceding claims, characterized in that the paper side and/or the machine side structured cover layer (4) is formed as a closed layer extending over the entire paper side (1) or machine side (2) of the belt, and/or the paper side and/or machine side structured cover layer (4) is impermeable to water, and/or the paper side and/or machine side structured cover layer (4) is characterized by a hardness in the range from 40 Shore D to 80 Shore D and/or the layer thickness of the paper side and/or machine side structured cover layer (4) is in the range from 1 to 5 mm.
6. Belt according to any of claims 2 to 4, characterized in that the paper side and/or the machine side intermediate structured layer (7) is impermeable to water, and/or in that the paper side and/or the machine side intermediate structured layer (7) is characterized by a hardness in the range from 40 Shore D to 80 Shore D, and/or the paper side and/or the machine side intermediate structured layer (7) is not formed as a closed layer but has interruptions, and/or the layer thickness of the paper side and/or the machine side intermediate structured layer (7) is in the range from 1 to 5 mm.
7. Belt according to one of the preceding claims, characterized in that the coating material of the paper side and/or machine side structured cover layer (4) has been produced from a multicomponent system, which is characterized by a pot life of less than 30 seconds, preferably less than 15 seconds, more preferably less than 10 seconds, and/or in that the coating material of the paper side and/or the machine side structured cover layer (4) is characterized by a viscosity of less than 1000 mPa s at a processing temperature lying in the range of 20°C to 120°C, in particular 60 to 90°C.
8. Belt according to any of claims 2 to 7, characterized in that the coating material of the paper side and/or the machine side intermediate structured layer (7) has been produced from a reactive system for producing an elastomer coating, which is characterized by a pot life of less than 30 seconds, preferably less than 15 seconds, more preferably less than 10 seconds and/or in that the coating material of the paper side and/or the machine side intermediate structured layer (7) is characterized by a viscosity of less than 3000 mPa s, preferably less than 1000 mPa s at a processing temperature in the range from 20°C to 120°C, in particular from 60°C to 90° C.
9. Use of a belt according to any one of claims 1 to 8 as a press belt, in particular transfer or shoe press belt in a paper machine, in particular a tissue paper machine, preferably in such a way that a paper or felt web which is guided through the machine comes into contact with the paper side of the belt, and/or in particular in the production of embossed paper, preferably embossed tissue paper.
10. Method for producing a transfer or shoe press belt, which is suitable for use in a paper machine and has a paper side (1) intended for supporting a paper or felt web and a machine side (2) facing away from the paper side (1), in particular according to one of claims 1 to 8, in which

    - a carrier (3) is provided,

    - and in which additionally on the paper side of the carrier (3) a structured cover layer (4) consisting of a coating material comprising or consisting of at least one polymer, in particular polyurea and/or polyurethane, is produced, which is at least on its side facing away from the carrier (3) characterized by a structured surface having a plurality of elevations (5) and depressions (6), wherein the structured cover layer (4) in particular is produced by applying a coating material by a spray or curtain application or extrusion process, and grinding the structured cover layer (4) such that the height of the elevations (5) is reduced but no smooth surface is obtained,

    - or in which additionally on the machine side of the carrier (3) a structured cover layer (4) consisting of a coating material comprising or consisting of at least one polymer, in particular polyurea and/or polyurethane, is produced, which is at least on its side facing away from the carrier (3) characterized by a structured surface having a plurality of elevations (5) and depressions (6), wherein the structured cover layer (4) in particular is produced by applying a coating material by a spray or curtain application or extrusion process, and grinding the structured cover layer (4) such that the height of the elevations (5) is reduced but no smooth surface is obtained,

    - or in which additionally on the paper and on the machine side of the carrier (3) a structured cover layer (4) consisting of a coating material comprising or consisting of at least one polymer, in particular polyurea and/or polyurethane, is produced, which are at least on ittheir side facing away from the carrier (3) characterized by a structured surface having a plurality of elevations (5) and depressions (6), wherein the paper side and machine side structured cover layer (4) in particular is produced by applying a coating material by a spray or curtain application or extrusion process, and grinding the paper side and machine side structured cover layer (4) such that the height of the elevations (5) is reduced but no smooth surface is obtained,

    wherein a reactive multicomponent system having two or more components is used to produce an elastomer coating to obtain the coating material for the paper side and/or the machine side structured cover layer (4), and a coating material is used for the paper side and/or machine side structured cover layer (4), which coating material is characterized by a viscosity of less than 3000 mPa s at a processing temperature in the range from 20°C to 120°C, in particular from 60°C to 90°C.
11. Method according to claim 10, characterized in that
    a paper side structured cover layer (4) is produced and prior to its production on the paper side of the provided carrier (3) a structured intermediate layer (7) from a coating material comprising or consisting of at least one polymer, in particular polyurea and/or polyurethane, which at least on the paper side is characterized by a structured surface having a plurality of elevations (5) and depressions (6), is produced,
    or that a machine side structured cover layer (4) is produced and prior to its production on the machine side of the provided carrier (3) a structured intermediate layer (7) from a coating material comprising or consisting of at least one polymer, in particular polyurea and/or polyurethane, which at least on the machine side is characterized by a structured surface having a plurality of elevations (5) and depressions (6), is produced,
    or that a paper side and a machine side structured cover layer (4) is produced and prior to production of the paper sider structured cover layer (4) on the paper side of the provided carrier (3) a structured intermediate layer (7) from a coating material comprising or consisting of at least one polymer, in particular polyurea and/or polyurethane, which at least on its side facing away from the carrier (3) is characterized by a structured surface having a plurality of elevations (5) and depressions (6), is produced, and/or prior to production of the machine side structured cover layer (4) on the machine side of the provided carrier (3) a structured intermediate layer (7) from a coating material comprising or consisting of at least one polymer, in particular polyurea and/or polyurethane, which at least on its side facing away from the carrier (3) is characterized by a structured surface having a plurality of elevations (5) and depressions (6), is produced,
    wherein in particular the paper side and/or the machine side structured intermediate layer (7) is produced by applying the coating material to the carrier (3) by a spray or print or curtain application or extrusion process, and wherein in particular the paper side and/or the machine side structured intermediate layer (7) is produced by arranging on the paper side and/or the machine side at a predetermined distance of preferably 1 to 10 mm before or immediately on the carrier (3) a preferably lattice-shaped masking (8) partially covering the carrier (3) and applying the coating material to the carrier (3) being partially covered by the masking (8) by a spray or curtain application or extrusion process, wherein in particular the carrier and the masking being arranged at the predetermined distance in front of or directly on the carrier are moved during spraying or curtain application or extrusion, the travel speed of the carrier and masking being at least substantially the same, and/or the paper side and/or the machine side structured intermediate layer (7) is produced by printing a predetermined pattern of the coating material on the carrier (3) as an intermediate layer (7).
12. Method according to claim 10 or 11, characterized in that the paper and/or machine side structured cover layer (4) is produced such that the structured surface on the side of the structured intermediate layer (7) facing away from the carrier (3) penetrates into the structured cover layer (4).
13. Method according to one of claims 10 to 12, characterized in that a woven fabric or a spiral link belt or a knitted fabric or a scrim is provided as a carrier (3) and/or a carrier (3) is provided which has on the paper and/or machine side a structured surface with a plurality of elevations (5) and depressions (6), and in particular the paper side and/or the machine side structured cover layer (4) is produced directly on the carrier (3) and the paper side and/or the machine side structured cover layer (4) is produced in such a way that the structure of the paper or machine side surface of the carrier (3) penetrates into the paper or machine side surface of the structured cover layer (4).
14. Method according to one of claims 10 to 13, characterized in that the paper side and/or machine side structured cover layer (4) is produced as a closed layer (4) extending over the entire paper side (1) or machine side (2) of the belt, and/or the paper side and/or machine side structured cover layer (4) is produced as a layer (4) impermeable to water and/or the machine side structured cover layer (4) is produced as a layer (4) having a hardness in the range from 40 Shore D to 80 Shore D, and/or the paper side and/or machine side structured cover layer (4) is produced as a layer (4) having a layer thickness in the range from 1 to 5 mm.
15. Method according one of claims 11 to 14, characterized in that the paper side and/or machine side intermediate structured layer (7) is produced as a non-closed layer (7) having interruptions, and/or the paper side and/or machine side intermediate structured layer (7) is produced as a layer (7) impermeable to water, and/or the paper side and/or machine side intermediate structured layer (7) is produced as a layer (7) having a hardness in the range from 40 Shore D to 80 Shore D and/or the paper side and/or machine side intermediate structured layer (7) is produced as a layer (7) having a layer thickness in the range from 1 to 5 mm.
16. Method according one of claims 10 to 15, characterized in that a multicomponent system is used to produce the coating material for the paper side and/or machine side structured cover layer (4), which is characterized by a pot life of less than 30 seconds, preferably less than 15 seconds, more preferably less than 10 seconds and/or in that for the paper side and/or machine side structured cover layer (4) a coating material is used which is characterized by a viscosity of less than 1000 mPa s at a processing temperature in the range from 20°C to 120°C, in particular from 60°C to 90°c.
17. Method according one of claims 11 to 16, characterized in that a reactive system to produce an elastomer coating, preferably a multicomponent system having two or more components is used to obtain the coating material for the paper side and/or machine side intermediate structured layer (7), the system being characterized by a pot life of less than 30 seconds, preferably less than 15 seconds, more preferably of less than 10 seconds and/or in for the paper side and/or machine side intermediate structured layer (7) a coating material is used, which is characterized by a viscosity of less than 3000 mPa s, preferably less than 1000 mPa s at a processing temperature in the range from 20°C to 120°C, in particular from 60°C to 90°C.

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